LIBRARY 
ANNEX 


ea shyaile oseay 


(a Create nel Rae wnt enertie 
» ies 
‘ ie ort it eaten 
ne ea is youth sunbathe 
ie ifr oat 
‘ deat hep eamie 
‘i ni i a paren bonRNTE 
STR are A WTR Nh CF peeaaartct ens zk 


' j “hg : a anhieanb ea bs beeaneard pasiemanyranys 
RM ae | i i i wy ase Saat og beg 5 tenet ras ies See Pareslin Dabepriedesons lr yabebnne (odes 


trad Lillo ; feb ei pen pisinuaer 
“ese Swe Gro ONE Sy ets Chie ia iat eotbrtal gap Miglin ert sea 
: iby inieey hipaa ean fi i Phi p 
id maelsonhidyt , ie leis inpaei ecb cake eral ent 
ue Heda los: ie CoP tet cme ies aod es aca ie Papa mee Aine 
P vega dished 6 Mein poor tei ib paris aan et nee aa 
. my 2 2 “a 
Wea terpedni oracn bat fo kale " és ) 
aha tensirsed beOskok 6 Waselicacensh 3 f isin 
Pie eitee Fan y - 
WM iy ee apne be peeled 
anes ; ii Add i Fi inet Edn nucedern 
. rere de 
Aen aM ae oor 


i ushnben weit iis “e 
mp 
‘ nie Na Oe atal eeh melts eetate eid tite rere he ec aagars 
SO MRC HCG as fab ral wrod tae ere ey 4 Eeoianiee rer vee 
fai OMe sO Vara a at Le ied ie Coat Aria Girls deasineen Sead tageaacee pattie ee 


CORNELL 
UNIVERSITY 
LIBRARY 


ENGINEERING LiBRARY 


eee 


- ee a yr - -£ 
i il 


“pn - 


Cornell University 


Library 


The original of this book is in 
the Cornell University Library. 


There are no known copyright restrictions in 
the United States on the use of the text. 


http:/Awww.archive.org/details/cu31924003939901 


THE GEOLOGY 


OF 


ING VY JAAS Er 


A REPORT COMPRISING THE RESULTS OF EXPLORATIONS ORDERED BY 
THE LEGISLATURE. 


C. H. HITCHCOCK, 


State GEoLocisT. 


J. H. HUNTINGTON, WARREN UPHAM, G. W. HAWES, 


ASSISTANTS. 


PART III. SURFACE GEOLOGY. 
PART IV. MINERALOGY AND LITHOLOGY. 
PART V. ECONOMIC GEOLOGY. 


CONCORD: 
EDWARD A. JENKS, STATE PRINTER. 
1878. 


Ae oe ey 
bl KRY 


TABLE OF CONTENTS. 


Chapter. 


“ce 
ae 


II. 


III. 


Part III. SurracE GEOLOGY. 
MODIFIED DRIFT IN NEW HAMPSHIRE. 
By WARREN UPHAM, 
GLACIAL DRIFT. 
By C. H. Hitcucock, : 
APPENDIX TO PARTS I AND II, 
INDEX TO PART III, 


Part IV. MINERALOGY AND LiTHoLoGy. By G. W. Hawes. 


INTRODUCTION, . . . . .. 
THE MINERALOGY OF NEW HAMPSHIRE, 
LITHOLOGY, 

INDEX TO PART IV, 

APPENDIX, 


Part V. Economic GEoLocy. By C. H. Hrrcucock. 
METALS AND THEIR ORES, 
BUILDING MATERIALS, ETC., 


NATURAL FERTILIZERS, 
INDEX TO PART V, 


Page. 


Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 


LIST OF ILLUSTRATIONS. 


ILLUSTRATIONS PRINTED WITH THE TEXT. 


PART I. 


1, Section in Canaan and Stewartstown, 
2, Section in Brunswick and Stratford, 
3, Section in Barnet and Monroe, 
4, Section in Newbury and North Haverhill, 
5, Section in Bradford and Piermont, . 
6, Folded layer of clay, Fairlee, Vt., 
7, Section in Norwich and Hanover, . 
8, Section in delta of Mink brook, Hanover, 
9, Section east from Ledyard bridge, Hanover, 
1o, Section in Hartland and Plainfield, . 
11, Sand dune, Lebanon, 3 3 
12, Profile of kame of Connecticut valley, 
13, Section in Springfield and Charlestown, . 
14, Folded clayey layers, North Charlestown, 
15, Section of river bank, Rockingham, Vt., 
16, Section in Vernon and Hinsdale, 
17, Section in Woodstock, 3 : 
18, Section in Bridgewater and New Hampton, 
19, Section in Concord, 
20, Section of kame, Robinson’s station, 
21, Section in Manchester, 3 
22, Section in Merrimack and Litchfield, 
23, Section in Nashua and Hudson, 


Page. 
21 


23 
28 
29 
32 
35 
37 
38 
39 
4o 
42 
45 
5I 
52 
52 
56 
7o 
73 
79 
87 
95 
98 
99 


vi 


LIST OF ILLUSTRATIONS. 


. 24, Section of a kame, Bennington, south side, 

. 25, Section of a kame, Bennington, north side, 

g. 26, Section of modified drift under till, Hancock, 

- 27, South end of Upper Beech pond, Wolfeborough, 
. 28, Section near Weirs, 

. 29, Section in Ashland, 

. 30, Section in Wolfeborough village, 

. 31, Map of Clay point, Alton, 


2, Section of Clay point, Alton, . 


. 33, Map of a small area in Alton, 

- 34, Section crossing Fig. 33, 

. 35, Map of a small area in Alton, 

. 36, Section crossing Fig. 35, 5 

. 37, Obliquely stratified sand, ebchenier, 

. 38, Section in clay, Rochester, , 

. 39, Section of plain at Willand pond, Sonieaeisnils 
ig. 40, Section of kame, Dover, 

. 41, Sand overlain by till, Dover, . 

. 42, Section along Silver street, Dover, ‘ 
. 43, Section along Silver street, Dover, farther east, 
. 44, Section along Silver street, Dover, farther east, 
. 45, Section in Portsmouth & Dover Railroad excavation, Dover, . 
g. 46, Section in kame south-east of Pine Hill cemetery, Dover, 

. 47, Section in sand near Wheelwright pond, Lee, i : 
. 48, Section on Boston & Maine Railroad near Newmarket Junction, 
. 49, Granite shattered by glacial action, Manchester, 
. 50, Embossed rocks on Mt. Monadnock, 

. 51, Lunoid furrow—section, . 

. 52, Lunoid furrow—ground plane, 

. 53, Moraine in Stratford, 

- 54, Section of Boar’s Head, % 

- 55, Vessel rock, Gilsum, 

. 56, Elephant rock, N ewport, 

. 57, Great rock, Wentworth, . 

. 58, Glaciated stone, Moultonborough, . 

- 59, Section in till, Portland, Me., 

. 60, Section in till, Lyndeborough, 

. 61, Section in glacial drift, Ashland, 

. 62, Lake rampart, Moultonborough, 

. 63, Section in gravel, Whitefield, 

. 64, Section of Bald mountain, 


Page. 
107 


107 
108 
128 
131 
132 
133 
134 
134 
135 
135 
135 
135 
153 
153 
157 
158 
159 
159 
159 
159 
160 
160 
162 
162 
179 
180 
182 
182 
218 
255 
267 
268 
270 
278 
279 
283 
291 
310 
311 
365 


LIST OF ILLUSTRATIONS. vii 


Part IV. 
Page. 
View of Moat Mountains and North Conway, ‘ : i : : . - 136 
ParT V. 
Figs. 1-6, Improvement in voltaic amalgamators for gold and silver,—Rae’s 
patent, . : : . r - . : ‘ g , 14-16 
Fig. 7, Map of the Warren mine, . ; . 3 a a ; ‘ 7 . 48 
Fig. 8, Section at the tin mine, Jackson, . . : : A : . . 67 


CHARTS IN THE ATLAS. 


Holland’s map of New Hampshire—/ac-szmle, reduced. 

Carrigain’s map of New Hampshire—/ac-simzle, half size. 

Two sheets of panoramic views taken from several of the White Mountain summits,— 
from free-hand sketches. 

One sheet of panoramic views from mountain summits, drawn by means of a camera. 

Six sheets, combining the topography, contour lines, and geology of New Hampshire, 
with portions of that of the adjoining territory on all sides. Fourteen geological 
sections are attached. The horizontal scale is two and a half miles to the inch; 
contour lines for every one hundred feet altitude, and for every fifty feet in parts 
of Coés and Cheshire counties. 

Five sheets illustrating the surface geology of New Hampshire. 

Geological map of the Ammonoosuc mining district. 


ILLUSTRATIONS NOT PRINTED WITH THE TEXT. 


HELIOTYPES FROM DRAWINGS. 


Part Ill. 
Page. 
Plate I, Maps showing the modified drift of Connecticut river, Nos. 1-4, . - 20 
Plate II, Maps showing the modified drift of Connecticut river, Nos. 5-8, . ay BA 
Plate III, Maps showing the modified drift of Connecticut river, Nos. 9-13, - 40 
Plate IV, Maps showing the modified drift of Pemigewasset and Merrimack river, 
Nos. 1-5, ‘ a: : 70 


Plate V, Maps showing the modified drift of Merrimack, Contoocook, and Ashue- 
lot rivers, . . . . : : . : ‘é : . - 96 


viii LIST OF ILLUSTRATIONS. 


Page. 
Plate VI, Map showing modified drift in eastern New Hampshire, . Hl - 146 
Plate VII, Maps of the Andover and Haverhill (Mass.) series of kames, . 168 
Map of eastern America, illustrating glacial dispersion, . 2 F & - 324 
Part IV. 
Frontispiece, Beryl from Grafton. 
Plates II-XII, inserted at end of text, and described upon page . ‘ ‘ - 242 
ParT V. 
Mineral lands along Gardner mountain, : . . . : : . - 36 


HELIOTYPES FROM NATURE. 


ParRT III. 


Frontispiece, Churchill rock, Nottingham. 
Mt. Washington boulder, Conway, ‘ ‘ y : - 3 2 - 176 
Glaciated stones, Hanover, . 260 
Chase rock, Nottingham, 3 E 5 r i : ‘ ‘ - 264 
Ballard rock, Nottingham, . F 5 3 : F F F - . 266 
Bartlett boulder and gravel cut at Crawford house, 
Boulder in sand, and ice-drift over sand, . p P i ‘ - 276 
Glacial and modified drift, North Conway, . 7 . : ; : - 284 
Lenticular drift hills, Goffstown, . F 3 ‘ ‘ : F ‘ ‘ . 288 


270 


PART III. 


SURFACE GEOLOGY. 


CHAPTER I. 


MODIFIED DRIFT IN NEW HAMPSHIRE. 


BY WARREN UPHAM. 


} a portion of geological history of which we have our principal 
record in the Modified Drift, begins with the departure of the 
great northern ice-sheet, and extends from that time to the present. 
The deposits included under this title are the water-worn and stratified 
gravel, sand, and clay or silt, which occur abundantly in almost every 
valley in the state. These river-lands comprise the intervals, which are 
annually overflowed at the high water of spring, and successive terraces 
which rise in steps upon the side of the valley, the highest often forming 
extensive plains. 

The origin and distribution of these materials present many interesting 
questions. When the term was first employed, it was the prevailing 
opinion that modified drift was gradually formed from the unmodified 
glacial drift by the ordinary action of rain and streams; and similar 
materials in small amount have been added by these causes, which are 
still at work. The boulder that is separated from the ledge by frost, and 
carried forward by the heaviest floods of a mountain torrent, is on its way 
to form a part successively of the coarse rounded gravel, sand, and silt, 
over which the river flows on its journey to the sea. It is evident, 
however, that the high terraces and wide plains bordering our rivers 
were formed by much greater floods than those of the present time, 
laden with vast quantities of alluvium. Both the materials and the water 
for sweeping them into the valleys appear to have been supplied by the 


4 SURFACE GEOLOGY. 


melting of an immense sheet of ice. These deposits thus had the same 
origin with the glacial drift; but they have been modified, being sepa- 
rated from the coarser portions, and further pulverized or rounded, and 
assorted in layers, by water. 


Tue GLAcIAL PERIOD. 


The indications of a glacial period abound in all northern countries 
whose geology has been explored; and in New Hampshire they are prob- 
ably as well shown as in any part of the world. Underlying the modi- 
fied drift we often find masses of earth and rocks mingled confusedly 
together, without stratification or any appearance of having been depos- 
ited in water. These are the glacial drift or z#//, Unlike the modified 
drift, till is distributed with no reference to lines of drainage, and fre- 
quently covers the slopes or lies at the summits of our highest hills and 
mountains. The boulders which it contains, or which lie upon its sur- 
face, are of all sizes up to ten feet, or rarely even twenty or thirty feet, in 
diameter; and in this state they have nearly all been transported south- 
ward from their native ledges. Where an outcrop of rock is so peculiar 
that its boulders cannot be confounded with those from other ledges, we 
may trace them southward or south-eastward, but not in other directions. 
They are abundant near their source, and diminish in numbers and size 
as we advance. The till of New Hampshire contains boulders which are 
thus known to have travelled a hundred miles. Wherever till occurs, it 
is also found that the ledges have been commonly worn to a rounded 
form; and, if the rock is sufficiently durable, it is covered with long par- 
allel scratches or s¢vig, which have the same direction with the dispersal 
of rocks in the till.) The same areas are also characterized by extensive 
deposits of modified drift. 

To explain these related facts was a most difficult task, which remained 
after nearly all other great questions in geology had been settled. The 
theory which has now been received by most who have studied this sub- 
ject was first brought out prominently by Agassiz in 1840, and was based 
upon his studies of the glaciers in the Alps. There fields and rivers of 
ice several hundred feet in depth are found descending from the regions 
of perpetual snow, their rate of motion being from one to five hundred 
feet, or even more in their steepest portions, in a year. Many angular 


MODIFIED DRIFT IN NEW HAMPSHIRE, 5 


blocks and fragments which fall from the bordering cliffs are carried along 
on the surface of the ice, or are contained in its mass with others torn 
from the rocks over which it moves, and under its vast weight these act 
as graving tools to round and striate the ledges beneath. The similar 
striation of all northern countries, and the formation of the till, are proba- 
bly due to a similar cause, namely, a moving ice-sheet which overspread 
the continents from the north. 

This continental glacier had accumulated sufficiently deep to cover 
every mountain summit in New Hampshire. That it overtopped Mount 
Washington is fully proved by recent discoveries of the state geologist.* 
Its thickness farther to the north was so much greater than in this lati- 
tude that its immense weight caused the ice to flow slowly outward. 
The direction of its current in New England was between south and 
south-east. Its terminal front in the United States coincided nearly with 
the course of the Missouri and Ohio rivers, passing into the ocean south 
of Long Island. Its greater extent east of the Missouri resulted from the 
increased snow-fall of this side of the continent. The termination of this 
ice-sheet in the Atlantic, south-east of New England, was probably like 
the great ice-wall bordering the Antarctic continent, along which Sir J. 
C. Ross sailed four hundred and fifty miles, finding only one point low 
enough to allow the upper surface of the ice to be seen from the mast- 
head. Here it was a smooth plain of snowy whiteness, extending as far 
as the eye could see. The Humboldt glacier, in Greenland, discovered 
by Dr. Kane, is sixty miles wide where it enters the sea, above which it 
rises in cliffs three hundred feet high. All icebergs have their origin 
from glaciers which thus extend into the ocean, being broken off, because 
of their lower specific gravity, by the uplifting power of the water. 

Cause of the Arctic Climate. The conditions which brought on the 
severe climate of this epoch have been the subject of much speculation 
and discussion. A theory which, with much probability, refers the ice- 
sheet to an astronomical cause, and claims to determine the date and 
duration of the glacial period, was proposed by James Croll in 1864, and 
has been advocated by James Geikie in his recent work on the Great Ice 
Age. The earth’s path about the sun is not exactly a circle, but is a 


* See Chapter II of this volume. 


6 SURFACE GEOLOGY. 


nearly circular ellipse, so that at one point of its orbit it is somewhat 
farther from the sun than at the opposite point. This eccentricity of the 
earth’s orbit is not constant, but increases and diminishes through long 
periods. During the past fifty thousand years it has been comparatively 
small, and will continue so for the same time to come. The last period 
of great eccentricity began about 240,000 years ago, and lasted 160,000 
years. During this time the winters which occurred farthest from the 
sun, or in aphelion, would be longer and colder than now. The sum- 
mer’s heat would be increased in the same proportion, but it is argued 
that its length would not suffice to melt the annual accumulation of snow. 
This would gain slowly in depth, and become solidified, till a large part of 
this hemisphere would be enveloped in ice. At the same time the oppo- 
site side of the globe would have a short, mild winter, and a long, cool 
summer. Owing to other astronomical causes, known as the precession 
of the equinoxes and motion of the line of apsides, these different climates 
would not be permanent for each hemisphere during the whole of this 
long period, but they would be several times changed, prevailing by turns 
on each side of the equator. In 21,000 years the hemisphere which at 
first had its winter at aphelion would have passed through a cycle, in 
which its place in winter would have traversed the entire orbit,—falling 
after half this time at perihelion, and finally arriving at its first position. 
This theory accordingly supposes that an ice-sheet was produced several 
.times about each pole, alternating with long intervals of genial tempera- 
ture, in which it disappeared. Stratified deposits of sand or clay contain- 
ing organic remains have been found in Europe, underlaid and overlaid 
by till, proving the existence of mild inter-glacial epochs. Equally certain 
proofs of these are rarely found in America. Thick beds of modified 
drift in the midst of till occur in New Hampshire, but they do not appear 
to prove a disappearance and return of the ice-sheet. 

If glacial epochs are produced by a great eccentricity of the earth’s 
orbit, we should also expect indications of ice-action in the older rocks, 
and probably many coarse conglomerates have been formed in this way. 
The remote date to which this theory assigns the last glacial period is not 
improbable, as the amount of erosion effected by Niagara river since the 
ice age, and other facts bearing on this question, indicate a similar lapse 
of time. This, however, seems but as yesterday when it is compared 


MODIFIED DRIFT IN NEW HAMPSHIRE. 7 


with the distant Eozoic and Paleozoic past, in which the rocky strata 
of New Hampshire were deposited beneath the sea and upheaved in 
crumpled folds to form our hills and mountains. 

The theory of Mr. Croll,* which supposes that during the long period 
of great eccentricity glacial and warm inter-glacial epochs succeeded 
each other in cycles of 21,000 years, does not seem to be sustained so 
fully as we should expect by evidence of such warm intervals, which he 
thinks even in arctic latitudes would be nearly free from ice and snow. 
A consideration of what we have to explain by the agency of ice, and of 
the mode in which these results are likely to have been produced, seems 
to point to a very long, continuous period of glacial action, with times of 
retreat and advance, but not apparently of complete departure and return 
of a continental ice-sheet. By other writers the glacial climate is be- 
lieved to have been principally caused by a different distribution and 
elevation of the land, attended with changes in the direction of oceanic 
currents. Even if a supposed combination of such conditions could be 
shown to be adequate to produce the ice-sheet, it seems more reasonable 
to attribute its origin to an astronomical cause, which we know to have 
existed, with a tendency to bring about these results. As very intense 
cold is not required for the accumulation and preservation of snow and 
ice, may not the continually cool climate, when winter occurred in peri- 
helion during the period of great eccentricity, have kept the ice-sheet 
which was already formed from being melted? The rare testimony of 
any retreat and subsequent advance of the ice during the glacial period 
in America, with the vast results which were accomplished in this time, 
favor this view. 

The motion of the ice, being produced by the pressure of its own 
weight, and extending immense distances over a comparatively level but 
very irregular surface, must have been exceedingly slow. The average 
yearly progress of the glaciers of the Alps is about three hundred feet. 
The continental glacier, which striated the northern United States and 
Canada, must have had a much less slope. If its upper surface de- 
scended only one foot in two hundred, which in this state is consid- 
ered a very moderate railroad grade, the ice would increase one mile in 


*Croll’s Climate and Time, Amer. ed., pp. 76-78, etc. 


8 SURFACE GEOLOGY. 


thickness for every two hundred miles that we advance towards the head 
of its outflow at the north. Over the highlands between the St. Law- 
rence valley and Hudson bay it would have been three or four miles 
in depth, and at the same time probably much deeper over Greenland. 
Even with this vast accumulation of ice we have so gentle a slope to 
produce its motion that we can scarcely suppose this progress, at least 
in its lower portion, which passed over the very uneven surface of the 
land, to have exceeded one twelfth that of the glaciers in the Alps. This 
would give us an advance of twenty-five feet yearly, requiring 21,000 
years to move one hundred miles. If these conclusions are any ap- 
proximation to the truth, the highest rate of motion which could be 
attained by the ice-sheet at its greatest depth, continuing through half 
of this time, would seem quite inadequate to plough up and remove 
the extensive and thick deposits of stratified gravel, sand, and clay 
which we now find in New Hampshire, so that scarcely any traces of 
them would remain. Similar deposits of modified drift would have been 
formed at each melting away of the ice; and their almost complete 
removal in the epochs during which this theory supposes the ice-sheet to 
prevail seems improbable, when we consider the slowness of its motion. 

The accumulation of the vast thickness of ice which must have existed 
at the north, probably amounting to twenty thousand feet, seems also to 
require a longer time than Mr. Croll’s theory allows. The average rain- 
fall of New England is about three and a half feet, three fifths of which 
are evaporated from the surface, while two fifths flow to the sea. This 
rain-fall exceeds that of the continent northward and westward. Proba- 
bly it was from a precipitation of snow and rain of no greater amount 
that the ice-sheet increased in thickness from year to year. Melting and 
evaporation must have removed a large portion of this; and an annual 
addition of two feet of ice seems to be too high an estimate. The forma- 
tion of the ice-sheet would thus occupy all the time through which it is 
supposed to act in any single glacial epoch. 

Another consideration which adds to the probability that the ice-sheet 
continued through the whole period of great eccentricity, being princi- 
pally formed in the successive epochs when the winters occurred near 
aphelion, but not disappearing when winters fell at perihelion, is found 
in the great elevation of these ice-fields which over the White Moun- 


MODIFIED DRIFT IN NEW HAMPSHIRE. 9 


tains reached nearly or perhaps quite to the line of perpetual snow, while 
farther northward they rose far above this line. The very low tempera- 
ture which this must cause would seem to make it improbable that the 
changed proportions of heat received from the sun, such as to produce, 
if no ice existed, a mild winter and a cool summer, could melt this vast 
mass of ice and bring a temperate climate in its place. It is certain that 
this or some other cause partially melted this ice at times, and that it 
afterwards advanced, covering the territory from which it had retreated; 
but the work which the ice-sheet accomplished, the length of time requi- 
site for its formation, and the low temperature of the altitude to which 
it reached, render it improbable that it was several times wholly melted 
away, alternating with warm inter-glacial periods. The view here taken 
is, that the glacial period was principally produced by the last great 
eccentricity of the earth’s orbit, the changed proportions of heat re- 
ceived from the sun in the different seasons of the year favoring the 
accumulation and preservation of vast sheets of ice, which existed in the 
northern and southern hemispheres at the same time. 

Formation and Distribution of Till, The till or coarse glacial drift 
was produced by the long-continued wearing and grinding of the ice 
sheet. As this slowly advanced, fragments were torn from the ledges, 
and a large part of these were sooner or later held in the bottom of the 
ice, and worn to small size by friction upon the surface over which it 
moved. The resulting mixture formed beneath the ice is variously called 
the ground moraine, boulder-clay, or Lower Ti//, It consists of smoothed 
and striated stones, with fine detritus, which is usually a gravelly clay 
of dark bluish color, being always clayey, dark, and very hard and com- 
pact. The characteristics of the lower till are due to the mode of its 
formation. Most of its pebbles and boulders are glaciated, having 
rounded edges and smoothly-worn sides, which often retain striz. These 
show that the finer material in which they occur has been produced by 
the slow grinding up of these stones under the ice. The dark and usu- 
ally bluish color is due to seclusion from air and water during its forma- 
tion, as pointed out by Torell, leaving its iron principally in the form of 
ferrous silicates or carbonates. Its compactness and hardness are due to 
compression under the great weight of ice. Because of this quality, the 


lower till is commonly known as “hardpan.” 
VOL, III, 2 


TO SURFACE GEOLOGY. 


While this deposit was thus accumulating beneath the ice, great 
amounts of material, coarse and fine, were swept away from _hill-slopes 
and mountain sides, and afterwards carried forward in the ice. When 
this melted, a large portion of the material which it contained fell loosely 
upon the surface, forming an unstratified deposit of gravelly earth and 
boulders, which may be called the Upper Tz//. There is almost always 
a definite line of separation, at a depth varying from two or three to fif- 
teen or twenty feet, between the upper and lower till. It will be seen 
that the upper member is the one usually exposed at the surface, and it 
is often the only one present where only a thin covering of till is found. 
Its characteristics are the larger size of its boulders, which are mostly 
angular and unworn, and commonly derived from less remote localities 
than the glaciated stones in the lower till; the yellowish or reddish color 
of its fine detritus, produced by the hydrated ferric oxide to which its 
iron has been changed by exposure to air and water; and the compara- 
tive looseness of its whole mass. This division of the till into two 
members, which is very well marked throughout New Hampshire, is 
also conspicuous in Sweden and other parts of Europe; and the peculiar 
features of each have been recently pointed out by Dr. Otto Torell, of 
Sweden,* in nearly the same terms here used. 

The distribution of the till in this state and in eastern Massachusetts 
is quite irregular. Sometimes no considerable accumulations of it are 
seen for several miles, and the ledges lie at or near the surface. Else- 
where the till occurs in large amount, covering the ledges which are 
scarcely exposed over some whole townships near the coast. Wherever 
it is found plentifully, it is to a large extent massed in peculiar oblong or 
sometimes nearly round hills, which usually have quite steep sides and 
gently sloping, rounded tops, presenting a very smooth and regular con- 
tour. These hills are of all sizes up to one third or one half mile long, 
with two thirds as great width; and their longest axis is most frequently 
north-west to south-east, coinciding nearly with the current of the ice- 
sheet. Their height varies from forty or fifty to two hundred feet. These 
accumulations of till are most abundant near the coast, where they some- 
times occupy nearly the whole territory for many miles, while adjoining 


* Proceedings of American A iation for the Ad: t of Science, vol. 25, 1876. 


MODIFIED DRIFT IN NEW HAMPSHIRE. II 


areas on each side may be nearly destitute of surface deposits, showing 
only naked, striated ledges. The peculiar distribution of the till, the dis- 
persal of boulders, the course of striz, and other topics connected with 
the unmodified glacial drift, will form the subject of the next chapter of 
this report. Having taken this brief view of the glacial period, we are 
now prepared to understand the origin of the modified drift. 


Tue CHAMPLAIN PERIOD. 


The departure of the ice-sheet was attended with a comparatively 
rapid deposition of the abundant materials which it contained. It is 
probable that its final melting took place mostly upon the surface, so 
that at the last great amounts of detritus were exposed to the washing 
of its innumerable streams. The finer portions of these materials would 
be commonly carried away; and the strong current of the rivers which 
would be formed near the terminal front of the ice-sheet could transport 
coarse gravel, or even boulders of considerable size. When the glacial 
river entered the open valley from which the ice had retreated, or in the 
lower part of its channel while still walled on both sides by ice, its 
current was slackened by the less rapid descent, causing the deposi- 
tion, first, of its coarsest gravel, and afterwards, in succession, of its finer 
gravel, sand, and fine silt or clay. The valleys were thus filled with ex- 
tensive and thick deposits of modified drift, which increased in depth in 
the same way that additions are now made to the bottom-land or interval 
of our large rivers by the annual floods of spring. ‘The portion of the 
material contained in the ice-sheet which escaped this erosion of its 
streams formed the upper till, The abundant deposition of drift, both 
stratified and unstratified, during the final melting of the ice-sheet, has 
been brought into due prominence by Prof. James D. Dana,* who de- 
nominates this the Champlain period, deriving the name from marine 
beds of this era, which occur on the borders of Lake Champlain. 

The retreat of the ice-sheet was towards the north-west and north; and 
wherever the natural drainage was in the same direction, it would be for a 
time obstructed by the ice, forming lakes in which the deposition of mod- 
ified drift would be much different from that which took place where the 


* American Fournal of Science, Third Series, vol. v, p. 198, and various papers in vol. «. 


12 ‘ SURFACE GEOLOGY. 


slope was to the south. In New Hampshire, the portion of the Contoo- 
cook valley which extends through Hillsborough county was thus occu- 
pied by a lake during a large part of the Champlain period. 

Kames. The oldest of our deposits of modified drift are long ridges or 
intermixed short ridges and mounds, composed of very coarse water-worn 
gravel, or of alternate layers of gravel and sand irregularly bedded, a sec- 
tion of which shows an arched or anticlinal stratification. Wherever the 
ordinary fine alluvium also occurs, it overlies, or in part covers, these 
deposits. Similar ridges of gravel have been often described by European 
geologists, under the various names of Kames in Scotland, Eskers in Ire- 
land, and Asar in Sweden. The first of these names will be adopted in 
this report. They have also been described by geologists in many por- 
tions of the northern United States. In New Hampshire, kames are of 
frequent occurrence, sometimes a single one extending in a very steep, 
narrow ridge for miles along the lowest portion of a valley, or elsewhere 
short and several parallel to each other, or in very irregular mounds and 
ridges, with hollows enclosing small ponds. Their position is generally 
along the middle or lowest part of the valleys, which are bordered by high 
ranges of hills; but in the south-east part of the state, in some parts of 
Maine, and in eastern Massachusetts, where there are only scattered hills 
with the valleys not much below the general level of the country, these 
ridges, of smaller size than in the great valleys, are found extending usu- 
ally north and south, without special regard to the present water-courses. 
In the valleys of our two largest rivers, the Connecticut and Merrimack, 
they extend long distances, but had heretofore escaped notice, owing to 
the large amount of levelly stratified alluvium, forming the conspicuous 
terraces and plains by which the underlying kames are often nearly 
concealed. Before this later alluvium was deposited, a kame had been 
formed in the Connecticut valley, which extended for many miles in a 
single continuous ridge, from one hundred to two hundred and fifty feet 
high, with steep sides; and in the Merrimack valley a continuous series 
of kames had been formed, consisting sometimes of a single ridge, and 
again of several parallel to each other. Another interesting series of 
kames extends from Saco river to Six-mile pond, and from Ossipee lake 
south-easterly along Pine river, and by Pine River and Balch ponds into 
Maine. The first description of any of these ridges in America appears 


MODIFIED DRIFT IN NEW HAMPSHIRE. 13 


to have been given by Dr. Edward Hitchcock in 1842,* respecting a 
series which is well shown in Lawrence and Andover, Mass. Short 
kames, and small areas occupied by a confusion of gravel ridges and 
mounds, but not connected with any extended series, are also frequently 
found. 

The origin of the kames has been a question much discussed by Euro- 
pean geologists, and the theory commonly accepted on both sides of the 
Atlantic was, that they were heaped up in these peculiar ridges and 
mounds through the agency of marine currents during a submergence of 
the land. Even if such ridges could be formed by this cause under any 
circumstances, it seemed impossible to account thus for the kames in the 
Connecticut and Merrimack valleys, which, being bordered on both sides 
by high hills, would have been long estuaries open to the sea only at their 
mouths, and therefore not affected by oceanic currents. From the posi- 
tion of these peculiar accumulations of gravel, which are overlaid by the 
horizontally stratified drift, the date of their formation is known to be 
between the period when the ice-sheet moved over the land and that 
closely following, in which this more recent modified drift was deposited 
in the open valley from the floods that were supplied by the melting ice. 
We are thus led to an explanation of the kames, which seems to be sup- 
ported by all the facts observed in New Hampshire, and which appears to 
apply, also, to the similar deposits which have been described in other 
parts of the United States and in Europe. During the melting of the 
ice-sheet it became moulded upon the surface, by this process of destruc- 
tion, into great basins and valleys; and at the last the avenues by which 
its melting waters escaped came gradually to coincide with the depres- 
sions of our present surface. These lowest and warmest portions of the 
land were first uncovered from the ice; and as the melted area slowly ex- 
tended into the continental glacier, its vast floods found their outlet at 
the head of the advancing valley. This often took place by a single 
channel, bordered by ice-walls, as was the case along the whole Connecti- 
cut kame; but in the Merrimack valley, and in eastern New Hampshire 
and Massachusetts, these glacial rivers also frequently had their mouth by 
numerous channels, which were separated by ridges of ice. In these 


*Tr tions of the A iation of American Geologists and Naturalists. 


\ 


14 SURFACE GEOLOGY. 


channels were deposited materials gathered by the streams from the 
melting glacier. By the low water of winter layers of sand would be 
formed, and by the strong currents of summer layers of gravel, often very 
coarse, which would be very irregularly bedded, here sand and there 
gravel accumulating, and without much order interstratified with each 
other. Sometimes the melting may have been so rapid that the entire 
section of a kame may show only the deposition of a single summer, 
which would then be very coarse gravel without layers of sand. When 
the bordering and separating ice-walls disappeared, these deposits re- 
mained in the long ridges of the kames, with steep slopes and irregularly 
arched stratification. Very irregular short ridges, mounds, and enclosed 
hollows resulted from deposition among irregular masses of ice. 

The glacial rivers which we have described appear to have flowed 
in channels upon the surface of the ice, and the formation of the kames 
took place at or near their mouths, extending along the valleys as fast as 
the ice-front retreated. Large angular boulders are sometimes, but not 
frequently, found in the kames, or upon their surface. They appear to 
have been transported by floating ice. Their rare occurrence forbids the 
supposition that these deposits were formed in channels beneath the ice- 
sheet, from which many such blocks would have fallen upon the kames. 

The necessity of referring the formation of the gravel ridges to glacial 
rivers became apparent during the exploration and study of our modified 
drift in 1875; and in August, 1876, this was announced in a paper “On 
the Origin of Kames or Eskers in New Hampshire.”* In the revised 
edition of Geikie’s Great Ice Age, published in London in the winter of 
1876-77, this distinguished glacialist retracts his former opinion that the 
kames were heaped up by marine currents, and attributes their formation 
to sub-glacial rivers.| This may be the true explanation in some cases, 
for such rivers probably existed through the glacial period; but more 
commonly it would appear, as already shown, that the kames were depos- 
ited at the final melting of the ice-sheet in channels formed upon the 
surface of the ice. 


% Proceedings of American Association for the Advancement of Science, vol. 25. 


+ Great Ice Age, second edition, revised, pp. 217, 239, 243, 469,478, etc. By page 414 it appears that this theory 
was first proposed by Mr. D. Hummel of the geological survey of Sweden, in 1874; and on page 415 allusion is 
made to a recent paper by Dr. N. O. Holst, also of Sweden, in which the kames have been explained in the 
same manner as in this chapter. 


MODIFIED DRIFT IN NEW HAMPSHIRE. 15 


Plains and Terraces. The extensive level plains and high terraces 
which border our rivers, constituting the most conspicuous and by far 
the largest portion of our modified drift, were also deposited in the 
Champlain period. The open valleys became gradually filled with great 
depths of horizontally stratified gravel, sand, and clay, which were brought 
down by the glacial rivers from the melting ice-sheet, or washed from 
the till after the ice had retreated, and which were deposited in the same 
way as by high floods at the present time. The departing ice-sheet was 
the principal source both of the vast amount of material and of water for 
transporting it into the valleys, which appear in most cases to have been 
filled to the level of the highest terraces or plains. The prevailing hori- 
zontal stratification of these deposits shows that they were spread. over 
large areas by the current of the floods which held them in suspension. 
The modified drift thus increased in depth in the principal valleys through 
a long period, which may have continued until the last of the ice at the 
head of the valley and of its tributaries had disappeared. 


Tue TERRACE PERIOD. 


During the recent or terrace period the rivers have been at work exca- 
vating deep and wide channels in this alluvium. The terraces mark 
heights at which in this work of erosion they have left portions of their 
successive flood-plains. As soon as the supply of material became insuf- 
ficient to fill the place of that excavated by the river, a deep channel was 
gradually formed in the broad flood-plain. The process was very slow, 
allowing the river to continue for a long time at nearly the same level, 
undermining and wearing away its bank on one side, and depositing the 
material on the opposite side, till a wide and nearly level lower flood-plain 
would be formed, bordered on both sides by steep terraces. When the 
current became turned to wear away the bank in the opposite direction, a 
large portion of this new flood-plain would be undermined and re-depos- 
ited at a lower level; but the direction of the current’s wear might be 
again reversed in season to leave a narrow strip, which would then form 
a lower terrace. In this way the Connecticut river, along the greater 
part of its course on the west border of New Hampshire, has excavated 
its ancient high flood-plain of the Champlain period to a depth of from 
one hundred and fifty to two hundred feet for a width varying from one 


16 SURFACE GEOLOGY. 


eighth mile to one mile, leaving numerous terraces at each side. The 
Merrimack and Saco valleys show similar erosion, and it may be seen 
upon a small scale on every river in the state. On our largest rivers we 
see the highest plain in some places, and the lower terraces very fre- 
quently, being now undermined by the wear of the current, forming steep 
bluffs and banks. It seems impossible to explain in any different way 
the cause of the slope, often nearly as steep as is possible for loose mate- 
rials, which forms the abrupt face or escarpment of level-topped and 
horizontally stratified terraces. The finer character of the materials 
which compose the lowest terraces and the interval, or present flood- 
plain, is due to this wearing away and re-deposition by the river, which 
have been many times repeated, till what may have been at first gravel 
becomes very fine sand or silt. By each removal it is made one degree 
finer, and is deposited at a lower level and farther down the stream. The 
end of its slow journey is the sea, where it will help to make the sedi- 
mentary rocks of this epoch. It has completed a great cycle of changes, 
ending where the upheaved and contorted ledges from which it was de- 
rived had their remote beginning. 

Deltas of Tributaries. Upon entering the large valleys, tributary 
streams of comparatively narrow channel and rapid descent frequently 
formed extensive deposits in the Champlain period, similar in material 
to the flood-plain of the main valley, but having a greater height. Some- 
times these de/tas, being partially undermined, form conspicuous terraces 
a hundred feet above the highest normal terrace, which is the remnant of 
the river’s continuous flood-plain. The deposition of the modified drift 
of the main river was usually but not always to the same level across the 
valley. The increased supply from tributaries was sometimes a tempo- 
rary barrier, damming up the waters of the main valley above; and the 
current could then deposit its sediment principally upon one side, making 
the highest normal terraces quite different in elevation. 

Dunes. Wind-blown banks of sand or dunes, apparently isolated on 
the hillsides, are occasionally found along the east side of Connecticut 
and Merrimack valleys and south-east of Ossipee lake, at heights vary- 
ing from the level of the highest terrace or plain to two hundred feet 
above it. These patches of sand are very conspicuous, because they are 
often destitute of vegetation, being blown in drifts by the wind. They 


MODIFIED DRIFT IN NEW HAMPSHIRE. 17 


vary in size, the largest sometimes covering an acre or more, with their 
thickest portions from ten to fifteen feet in depth. These dunes appear 
to have been swept up from the broad plains of the Champlain period, 
before forests had fully covered the land, by the strong north-west winds, 
which we may suppose prevailed the same then as now. That this is a 
true explanation of these high banks of sand appears to be proved by the 
fineness of their material, which contains only particles such as could be 
carried by the wind; by their frequent occurrence on the east side of the 
valleys, where they would be formed by the prevailing strong north-west 
winds, while they are not found on the opposite side; and by the train 
of sand-drifts usually grassed over, which may be traced down in a north- 
west direction from the banks of sand now blown by the wind to the 
normal modified drift. Since the clearing away of the forest, the upper 
portion of these trains of sand has sometimes been carried several hun- 
dred feet onward, and from thirty to fifty feet higher. The excavation 
of the old drifts has been six or seven feet in depth, as shown by great 
stumps, beneath which the sand has been swept away. These dunes are 
ridged, channelled, and heaped up by the wind in the same manner as 
the more extensive dunes of a sea-coast. 

Modified Drift overlaid by Till. About Winnipiseogee lake beds of 
stratified clay are often found underlaid and overlaid by till. The clay is 
free from pebbles, and well suited for brick-making. It varies from five 
or ten to thirty feet in thickness, and occurs at various heights from the 
level of the lake to three hundred feet above it. The overlying till is from 
two or three to ten or fifteen feet in thickness, wholly unstratified, and 
very coarse, containing numerous boulders, which may be five or six feet 
in diameter. These remarkable clay-beds probably accumulated during 
the departure of the ice-sheet, in spaces melted under the ice, between it 
and the lower till. 

Modified Drift near the Coast. About Dover, and southward near the 
sea-coast, thick deposits of modified drift, sometimes forming extensive 
plains, are found occupying areas of water-shed from one hundred to two 
hundred feet above the streams, which often flow in wide valleys that are 
nearly destitute of modified drift. Some of these, as the high plains of 
coarse gravel and sand about Willand and Barbadoes ponds, near Dover, 


seem to have been produced by the rapid deposition of materials brought 
VOL, Ill. 3 


18 SURFACE GEOLOGY. 


down from the ice-sheet by glacial rivers. At the time of their formation 
the adjoining valleys were probably still occupied by the unmelted ice. 
Nearer to the coast we_find in this situation beds of fine gravel, sand, or 
clay, sometimes enclosing marine shells and pine cones, and in several 
instances overlaid on their north-west side by coarse glacial drift or 
upper till a few feet in depth, giving evidence of a retreat and subsequent 
advance of the ice sheet. 

Submergence by the Sea. These marine deposits, which reach to about 
one hundred and fifty feet above the sea, afford the only certain proof 
found in our exploration of the modified drift in New Hampshire of any 
change in the relative heights of land and ocean. With the exception of 
the trunks, branches, and leaves of trees, which have been rarely found, 
all the rest of our modified drift is, so far as known, destitute of organic 
remains; and we have seen that the explanation of the thick deposits 
of the Champlain period, and of their present excavated and terraced 
condition, requires no submergence by the sea, nor change in the 
height and slope of the land. It seems quite probable that the sub- 
mergence in the glacial period, of which we have proof, amounting to 
fifty feet in southern New England, two hundred feet on the coast of 
Maine, and about five hundred feet in the valley of the St. Lawrence, was 
not caused by any downward and upward movement of the earth’s sur- 
face, but by the attraction of the immense masses of ice, which, as pointed 
out by Adhémar, would draw the ocean away from the equator towards 
the poles. The whole amount of water in the sea was diminished, but 
the accumulation of vast sheets of ice, several miles in thickness, would 
be sufficient to retain the ocean at its present height near their lower 
limits, while it would rise much higher than now about the poles, and at 
the equator would sink far below its present level. Such a rise of the 
sea, increasing in amount at high latitudes, is attested by the modified 
drift of both America and Europe; and coral islands afford proof of the 
corresponding depression of the ocean, succeeded by a gradual elevation 
to its present height, over large areas within the tropics. 

The two great continents appear to have existed, with somewhat the 
same outlines as now, from a very remote geological epoch. From the 
Silurian age to the glacial period we have no record that any part of New 
Hampshire was submerged beneath the ocean; and nearly all that we can 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. I9 


say of its history through this vast extent of time is, that it probably had 
for the most part a temperate climate, and witnessed the same slow suc- 
cession in its forms of vegetable and animal life of which the coal meas- 
ures and later rocks in other parts of the United States bear witness. 
This comparative stability through long ages makes it more probable that 
these recent changes in the relative heights of land and sea are due to 
the cause which we have explained rather than to movements of the land. 

The exploration of the modified drift in New Hampshire, under direc- 
tion of the state geologist, was principally made in 1875. In this work 
on the Connecticut and Merrimack rivers the author had the valuable 
assistance of William F. Flint, being thus enabled to map all the terraces 
of these rivers, and measure their heights by an engineers’ level. On the 
Connecticut, this was more conveniently done, and the expense lessened, 
by employing a boat, which was built by Mr. Flint, for the journey be- 
tween McIndoe’s Falls and Massachusetts line. The particular descrip- 
tion of the modified drift of the state will be taken up in the following 
order: Connecticut river, followed by such of its tributaries as have been 
examined; Merrimack river, followed by Contoocook river and Winnipi- 
seogee and Squam lakes; Androscoggin river; Saco river and basin of 
Ossipee lake; basin of Piscataqua river; and the sea-coast. 


Mopirizep Drirr ALONG CoNNECTICUT RIVER. 


The sources of Connecticut river, its hydrographic basin, its course 
and descent on the west side of New Hampshire, and its tributaries from 
this state, have been described in the first volume of this report.* The 
territory of Vermont extends to the west shore of this river, but in explor- 
ing its modified drift equal attention has been given to both sides. Only 
by this study of the whole valley could the history of these deposits be 
discovered, and the portion in this state be understood. A series of 
maps occupying three plates accompanies the following descriptions. 
The various terraces which border the river are there delineated, and 
their heights stated in feet above the sea. The extent and contour of 
the modified drift is thus shown along the whole valley. Throughout 
this distance the alluvial area is bounded on each side by high hills, 
which are only interrupted by the entrance of tributaries. 


* Vol. i, pp. 222-224, 299, 302-305, and 318, 


20 SURFACE GEOLOGY. 


Connecticut Lake to West Stewartstown. For the first four miles below 
Connecticut lake the river has a rapid descent, with a southerly course. 
It then bends to the west, and winds with a sluggish current through a 
narrow swamp three miles in length, which is the first alluvium seen on 
the river. Its lower end is at the mouth of Deadwater stream. One 
half mile farther down, at the outlet from Back lake, the road passes over 
a sand and gravel plain 30 feet above the river. This is material de- 
posited in the Champlain period by the tributary stream. Much of it has 
been excavated during the terrace period; and till extends to the river 
on the opposite side in a very gentle, regular slope. 

On Indian stream there is a large extent of low alluvial land, com- 
prising several valuable farms. This consists mainly of a wide interval, 
from 10 to 15 feet high, which is bordered on the east by a narrow 
lateral terrace from 30 to 40 feet above the river. In the next four 
miles scarcely anything but glacial drift and ledges is found. The 
scanty portions which may be called modified drift consist of very coarse, 
somewhat water-worn gravel, in terraces from 10 to 40 feet above the 
river, which has probably in many places cut its channel to this depth 
through the till, About the mouth of Bishop’s brook considerable low 
alluvium occurs, partly brought by the main river and partly by its 
tributary. Thence we have a narrow width of modified drift on the 
north side of the river to Hall’s stream, which is bordered by an inter- 
val from 5 to 10 feet, and two terraces, 20 and 35 feet, above the 
river. On the south side here, and on both sides for nearly two miles 
below, the river is closely bordered by hills, and no modified drift is seen. 

The portion of the river which we have now described extends south- 
westerly about eighteen miles from the mouth of Connecticut lake. The 
descent in this distance is 583 feet. High wooded hills border the valley, 
which is destitute of modified drift for half of the way. The largest allu- 
vial area is on Indian stream; and the highest terraces are from 30 to 40 
feet above the river. 

Upper Connecticut Valley. Below West Stewartstown the course of the 
river is southerly, having a descent in nearly fifty miles, to the head of 
Fifteen-miles falls in Dalton, of only 205 feet, one half of which takes 
place in nine miles between Columbia bridge and North Stratford. Along 
this whole distance the modified drift is continuous, and, including both 


a7 luce 4. 


rs lapation. : 

Bige f Glacial Drift vassreere0r 

rave oh , or Katmos, wren a f 

i A 

the Modified Drift of “Py: cogeep% Z Ki 

. ¢ R ; No Ne 7  perenth ale 235 
ONNECTICUT RIVER, __): Rectan A DES Saal 


Cc . s; Riv., 
ALE OF MILER « oA 7 | T T U R Canaan, ee 008 Rice 
Nos.1-4. 4 - j 

Naf, 


. Colebrook + 1026; » 1010 
Columbia. «012; + 992 


OM Str. Hollow « a - 858. 0 
ey é i NY wa eA Groveton * 901. ‘ 
Elias ws Northumberland Falls,552- 
. . at Eee) * Eee... Lancaster,Court Ho, B61; Riv, 635. 


J 


7 


a 
¥ 
OWN 


: 
EWARTST 


& Re - 
_— 1S) SecTiON, . frag, We 


This border ts the true meridian for all the 21aps enclosed. 
N 


i, 
aed 
o 
3 
2 a 
a é 
that 
wee 
0, 


| onl f s 
sey @ Hollow 
< aif 6 ial 
2/8 gh laa cee 7 
= fc e Ak , 8 me Fe Fenatham is; 
Qa Bake et en Q20% 1S i got 
3 865. v °o 
- a\$ g os: 4 2 
=o 3  % vhs of 
= 2 |S Sper Fa iy Nie : = 
(a) A= & z =a 8905; = PR. 
1 Rsssn.g ae Pe if “3 
SOG SS 4 oO /'365; [ 890.— al 
iN { Paes 
Ly a, aA Z 2 se Greve Ms 
Oe y . 
¥ a ay ' 
sien Ba Pe my oN Bow p 
i Be Ne ~ xy Re Le Pe 
hy S 3 
Gf : : ‘get 
eT ‘G, SSNS Ast: a 
ard 7 REB52. 
850 a = 223 Mt. Lyon 
2 850, if eta 


HELIOTY PE 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 21 


sides, is usually a half to a mile and a half wide. It is very simple, hav- 
ing two heights, and consists of the present flood-plain, bordered by 
remnants of that which filled the valley in the Champlain period. The 
former is about ten feet above low water, being annually overflowed by 
the floods of spring. This would be called dottom-land in the western 
United States. In New England it is commonly termed izéerval,; but 
along Connecticut river it is frequently known as meadow. On all our 
large rivers this lowest terrace has a firm and well-drained surface, much 
different from the marshy areas bordering small streams to which the 
name meadow is restricted in other parts of the state. It is the most 
valuable portion of these alluvial lands, having a more finely-pulverized 
and more fertile soil than that of the higher terraces. The ancient flood- 
plain is here represented by a lateral terrace, from 40 to 120 feet above 
the river, usually remaining at both sides, and in many places forming 
considerable plains. 

From West Stewartstown to Colebrook the only alluvium of impor- 
tance on the New Hampshire side is the interval; but small remnants of 
the upper terrace are found, especially where there is a tributary stream. 
On the Vermont side the upper terrace, composed of sand or fine gravel, 
is usually well shown, having a nearly constant but small elevation of 40 
to 60 feet above the river, with which it slopes. It appears that this 
formerly had possession of the whole valley, and that the channelling of 
the river has swept it away from the area now occupied by the interval 
or meadows. Portions of 


fe} 
3 3 8 ba 8 nw. 6 
it still remain, entirely sur- $2 88g FS E. 
Ww. 

rounded by the low flood- 1000 ft 

. ee ee eee ee wa eaden above sea. 
plain. Such a plateau may Fig. 1.—SECTION IN CANAAN AND STEWARTSTOWN. 
be seen in Canaan, nearly Length, # of a mile. 


opposite the south line of Stewartstown. The upper terrace and its 
isolated remnant have both a height of 40 feet above the river, while the 
lower level is only 15 feet in height. North-east from this in Stewarts- 
town a rivulet has effected a like result on a small scale in the meadow, 
cutting a channel wholly around a small area which still preserves the 
height of the rest of the meadow. 

Kames. At Colebrook we find an interesting gravel ridge or kame, 
portions of which remain north of the junction of Beaver brook and 


22 SURFACE GEOLOGY. 


Mohawk river, but most noticeably west of the village, extending nearly 
a mile parallel with the river. Its height is about 70 feet above the river, 
and 50 above the low alluvium on each side. Its material is the same 
as that of the long kame farther south in this valley, being principally 
coarse, water-worn gravel, with abundant pebbles six inches to one foot 
in diameter. This ridge was deposited in the glacial channel of the river 
which flowed from the ice-sheet at its final melting. 

We must refer to a similar cause the slightly modified drift in Leming- 
ton, just north-west from Colebrook bridge; in Columbia, the high gravel 
terrace north of Sims stream; thence for a mile southward the moraine- 
like, level-topped or irregular drift, slightly modified, at about 100 feet 
above the river; and the coarse drift ridge on the east side of the river a 
half mile above Columbia bridge. The last is a distinct ridge, one third 
of a mile long, parallel with the river, and from 50 to 75 feet above it, 
being from 25 to 50 feet above the adjoining lowland. This may have 
been a medial moraine. It contains many angular rock-fragments from 
two to three feet in size, and seems scarcely modified, appearing like por- 
tions of the kames along Merrimack river. 

Between Columbia bridge and North Stratford the descent is rapid and 
the terraces are irregular. At Columbia bridge the highest alluvial banks 
are 48 feet above the river; at North Stratford, 119. Where the river 
now descends 1o1 feet the stratified drift of the valley shows a slope 
of only 30 feet, or about three feet to a mile. After we pass this steep 
and narrow portion, and enter a wide valley again where the river is 
comparatively level, we find the upper terrace falling much more rapidly, 
or nine feet toa mile. At Groveton it has again descended to a height 
50 feet above the river. As we approach Fifteen-miles falls, the upper 
terrace slopes very slowly down to the lower, and they can scarcely be 
distinguished as separate heights below South Lancaster. The wide 
river-plain here rises gradually from 5 or 10 to perhaps 20 or 30 feet 
above the river. 

In Stratford and Brunswick both heights of the alluvium are well 
shown, the highway being on the upper terrace and the railroad on the 
meadow. The former is about 100 feet above the river, and at Bruns- 
wick Springs, and for much of the way through Stratford, is from one 
fourth to one third of a mile wide. At Stratford Hollow depot the rail- 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 23 


road has cut through a narrow spur of this terrace, which escaped erosion 
by water. Here the alluvium of the main valley has been excavated into 
secondary terraces 
by Bog brook. In 


R. 865. 


Moraine. 


880. 


fo] o) 
om a 
a rs) 


ie) 
ay 
a 


E. 

the south part of ™ Z pee 
a 50 ft. 

Stratford, and in ------- re. : Fe an secnaae above sea. 


Northumberland, Fig. 2.—SECTION IN BRUNSWICK AND STRATFORD. 
the meadow ox fins Length, § of a mile. 

terval occupies more space than the terrace, which has its greatest 
extent in the level, swampy plain west of Groveton Junction. In Maid- 
stone, for two miles north from Guildhall, low hills on the west side of 
the valley hem in extensive swamps, which have been scantily filled with 
alluvium of nearly the same height with the river terrace. 

Deltas. At Lancaster the upper terrace of Connecticut river is only 
15 or 20 feet above the interval. The only higher modified drift has 
been brought down by tributaries. Part of Lancaster village is built on 
one of these deltas, formed by Israel’s river on its south side, 50 feet above 
the terrace of the main valley. This delta sloped rapidly westward, and 
formerly occupied the whole area of the village; a portion of it, 20 feet 
lower than the former, remains at the cemetery opposite the court-house. 
Similar deposits also occur two miles south-west from Lancaster, and on 
John’s river. 

Between South Lancaster and Fifteen-miles falls the broad river-plain 
is unterraced. It seems probable that a lake existed here while the origi- 
nal high plain northward was being deposited. When this was channelled 
out by the river, so as to leave only terraces as we now see them, the 
materials excavated were sufficient to fill up the lake. It would be inter- 
esting to know the depth of the stratified drift in this basin; it is proba- 
bly deeper than the height of the highest modified drift northward above 
the river. 

Kame-like materials of small extent were noticed at North Stratford, 
forming the high bank on the east side of the railroad, one fourth mile 
south-east from the depot, and in Guildhall, about two miles north from 
Lancaster bridge. A remarkable moraine of granite boulders occurs in 
Stratford, covering a large area of hillside just above the upper terrace, 
one mile south from Beattie’s station. Two miles north-west from 


24 SURFACE GEOLOGY. 


Groveton a ridge of till, from 60 to 100 feet above the river, projects half 
a mile westerly into the valley, or half way across it, appearing like a ter- 
minal moraine. Horse-shoe pond, on the north-west side of this ridge, 
occupies a portion of a deserted river-channel. These ancient river-beds 
are frequently shown by such ponds, commonly called sloughs or moats, 
of which Baker’s pond, near Lancaster, is another example. We see the 
river now slowly changing its position by wearing away one or the other 
of its banks, and it has thus swept many times from side to side in exca- 
vating its valley between the bordering terraces. 

Fifteen-miles Falls. From the mouth of John’s river the Connecticut 
has a rapid descent for twenty miles, amounting to 370 feet, falling from 
830 to 460 feet above the sea. The bed of the river is a nearly continu- 
ous slope of coarse till, showing abundant boulders, but with scarcely any 
exposure of solid ledges. The only place where these were noticed in 
our exploration was at the “lower pitch,” or foot of these rapids, about 
a mile above the mouth of Passumpsic river. Here there is a precipitous 
fall of a few feet, and this is said to be the only point of abrupt descent. 
Tn other parts of its course the falls of the Connecticut are produced by 
ledges, and the channel, except at such falls, is composed of gravel, sand, 
or silt. Nowhere else below West Stewartstown, except at the falls of 
Northumberland and Columbia, and rarely, if at all, southward, does the 
river flow over the glacial drift or till. 

The noticeable features of the valley in this distance are, that it is deep 
and narrow, with sloping sides of till, and destitute of the level alluvial 
terraces and intervals which occupy a large width everywhere else along 
the river. Where any modified drift does occur, it is coarser than usual, 
being generally gravel, sometimes imperfectly rounded or water-worn, and 
its surface has commonly an irregular slope. The upper portion of these 
rapids is especially destitute even of such alluvial deposits, the highest 
that occur being from 60 to 75 feet above the stream. It is frequently 
evident that the source of these deposits is not the main river, but a trib- 
utary, as in the case of Niles stream in Concord, Vt., and on both sides 
at Upper Waterford. These deltas are greater in height, as well as in 
amount, than the scanty remnants of the alluvium of the main valley. 

On the lower portion of these rapids the modified drift appears in 
greater quantity and at a much increased height. Opposite Lower 


Plate U. 


This border rs the trae mertdian Hine for all the maps enclosed. 


7 


a 


ey 
E | 2a Be 


OPS 


SHOWING 


the Modified Drift of «3 %& ‘ 
4s Connecticut River. ; 


SCALE OF Mites. 


1 


Le 
Explanation. 
[Edge of Glacial Drift. oR 
Boundary between Terraces,-.-- 
par cae or Kames, woven 
Ancient River-beds, rumen 
Roads,with houses, + 
Higures denote height 
in feet above the sea. 


we 


HELIOTYPE 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 25 


Waterford we find irregular hillocks of sand, barren of vegetation, and 
drifted by the wind, the highest of which are about 200 feet above the 
river. Below this point the modified drift rises in irregular slopes to a 
height of 200 feet in several places, and its position shows it to have been 
principally deposited from currents of the main valley. As we approach 
the foot of the falls its coarse character is changed, and sand predomi- 
nates in the place of gravel. These deposits probably once filled this 
part of the valley nearly 200 feet above the present river, sloping in six 
miles between Lower Waterford and Passumpsic river from about 800 to 
650 feet above the sea. 

The course of the river along Fifteen-miles falls is S. 70° W., being 
turned much to the west from its general direction. This course is at 
right angles to the line of motion of the great ice-sheet; consequently 
this valley was sheltered from the direct grooving and rasping of the ice, 
and must be supposed to have furnished a lodgment for much of the 
ground-moraine or till that accumulated in its track, We have men- 
tioned that this material forms the river channel, nearly everywhere con- 
cealing the underlying rocks. It also forms the sides of the valley for 
most of the way, rising quite steeply from the river, and sometimes pre- 
senting a terraced appearance at a height much above the present chan- 
nel. These considerations lead to the conclusion that the river has 
excavated much of its present deep, narrow channel through this till 
since the disappearance of the ice, and since the deposition of its highest 
modified drift. 

The facts observed point to an order of events somewhat as follows: 
In the ice-age a great amount of till was caught by the transverse valley. 
At the melting of the ice modified drift was swept into the valley, mass- 
ing in the largest quantity at its lower end, and deltas were deposited by 
tributary streams. In some places the wind seems to have blown up 
sand-drifts to a position on the hillside above the normal height of modi- 
fied drift. As soon as the melting had receded to a few miles above the 
head of these falls, further deposition ceased, all the material supplied 
being retained in the upper valley. The river next began the work of 
excavation. Most of the modified drift was carried away, and considera- 
ble depths channelled out in the till. It does not appear certain that a 


great amount of till was removed from the head of the falls; at least, 
VOL. III. 4 


26 SURFACE GEOLOGY. 


nothing seen in the surface geology of the valley above would require 
such a barrier. The depth of till thus removed must have been variable, 
sometimes probably amounting to 100 feet; and more or less of this exca- 
vation seems to have taken place along the entire extent of these falls. 
The irregular surface left by the ice has been thus reduced to a chan- 
nel of nearly regular slope with no abrupt falls, cut through the till, 
which still covers the ancient bed in which the river flowed before the 
glacial period. 

Lower Connecticut Valley. The early pioneers retained the Indian 
name Cods, which they found applied to the fertile intervals of Lancaster 
and Haverhill. These were the Upper and Lower Cods, separated by 
the Fifteen-miles falls. By a similar division, the whole extent below 
these falls is here called the lower valley. This is comparatively level 
and straight, with a southerly course nearly the same as that of the upper 
valley. Ina direct distance of 118 miles from:the mouth of Passumpsic 
river to Massachusetts line, the river flows 137 miles, descending from 
460 to 180 feet above ‘the sea, or two feet to the mile. The principal 
falls in this distance are Beard’s falls at Barnet, 5 feet; McIndoe’s falls, 
10 feet; Dodge’s falls, three and a half miles south, 5 feet; at Woods- 
ville, about 10 feet; White River falls, 35 feet (see map, vol. i, p. 302); 
Sumner’s or Quechee falls, two miles below the mouth of Quechee river, 
5 feet; and Bellows falls, 49 feet,—making a total of 119 feet, and leav- 
ing an average descent, excluding falls, of 13 feet per mile. 

The modified drift of this lower valley is everywhere well developed, 
and occurs in extensive terraces of various heights, three or four often 
on each side, the upper one being usually from 150 to 200 feet above the 
river, while the lowest is the interval or meadow. The largest plains are 
expanses of the upper terrace, or of still higher tributary deltas. These 
areas are generally of a clayey, moist, productive soil, quite in contrast 
with the dry sandy plains of Merrimack river, Ossipee lake, and other 
parts of the state. The nearest resemblance to these barren “pine-plains” 
is found at Woodsville, in the high delta of Lower Ammonosuc river, on 
the north side of Black river in Springfield, Vt. and in the high, broad 
plain of Hinsdale. The latter is the only one of these areas which can 


be compared in size with the extensive plains of central and eastern New 
Hampshire. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 27 


The most extensive intervals or meadows are between Woodsville and 
Bradford, Vt., 12 miles long and one half to one mile wide, including the 
Lower Coés intervals of Newbury, Vt., Haverhill, and Piermont; and in 
Charlestown and Rockingham, Vt. 6 miles long and half a mile wide. 
But, in addition to these, smaller areas, up to a mile or more in length 
and a few rods to a half mile wide, are of common occurrence along the 
entire valley. These bottom-lands are very fertile, being composed of 
the finest silt, and enriched every year by a coating of mud from the 
turbid freshets of spring. Many of the lower terraces which are not 
overflowed are of the same material; but the higher terraces usually 
show some intermixed sand or fine gravel. 

These lateral terraces are less plainly continuous in extent and height 
than the intervals or the upper terrace. They are sometimes numerous, 
again wanting; seldom agreeing in height on opposite sides; usually 
showing a slight slope with the river, but not often more than one or two 
miles, and generally less than one mile in length, and succeeded by others 
higher or lower. An examination of them over long distances, however, 
sometimes shows a well-marked series, descending with the river, and 
recording a height at which, during the process of erosion, it remained 
nearly stationary for an unusual length of time, forming a broad and 
continuous flood-plain, now interrupted and mainly swept away by the 
further deepening of the channel. These terraces are almost always 
level-topped, and bounded at the face by a steep escarpment; and their 
appearance is sometimes very striking, and even grand, as they rise in 
gigantic steps on the side of the valley, shaped with a smoothness, 
order, and beauty which could not be surpassed by art. 

The greatest widths of modified drift that can be measured in this 
valley, on the west side of New Hampshire, are in Haverhill and 
Newbury, two miles, and in Hinsdale and Vernon, two and a half miles 
wide. The average width is fully one mile. The narrowest places are 
at Shaw’s mountain, near the south line of Bradford, Vt., and at Barber’s 
mountain, in Claremont, both of which occupy the middle of the valley, 
with narrow belts of alluvium on each side; at the west side of Rattle- 
snake‘hill, Charlestown; and at the south end of Wantastiquit mountain, 
below Brattleborough, Vt. We do not discover, however, at these places, 
or elsewhere, any evidence of former barriers, which could have made the 


28 SURFACE GEOLOGY. 


valley a series of lakes. The vast amounts of modified drift which accu- 
mulated in this valley do not appear to have filled ancient lake-basins, but 
to have been rapidly deposited from the immense floods supplied by the 
melting of the ice-sheet. These great deposits of modified drift, for which 
there appears no other adequate cause, should rank with the till, striz, 
and embossed ledges, as proof of a former continental glacier. 

The Passumpsic river must be considered as occupying the continua- 
tion of the lower Connecticut valley, but at its mouth it flows through a 
rocky gorge, which separates its numerous and high terraces from those 
of the Connecticut. Four or five terraces are shown here on the Monroe 
side, the highest 190 feet, and the lowest from 15 to 20 feet above the 


648. 


The Nine Islands. 


w 
w 
A=) 


R.R.490. 


ce} 
i} 
+ 


450 ft. 


Ne erat epee S foe ea ne masem. abovesca. 


Fig. 3.—SECTION IN BARNET AND MONROE, AT MoutH oF Pas- 

SUMPSIC RIVER. Length, 1 mile. 
river. The latter forms the Nine Islands, of which only one is above the 
reach of high water. This is a wooded island close to the Vermont side, 
and forms a north and south ridge 50 feet above the river, composed in 
part of kame-like gravel. Delta terraces from 50 to 60 feet above the 
highest in the main valley have been brought down by Stevens river, 
which falls 100 feet in Barnet village. Gleason’s islands, one mile below, 
like nearly all those found in the river southward, are alluvial interval. 
Several terraces appear at McIndoe’s falls, on the widest of which the 
village is situated, 50 feet above the river. The high terraces do not 
present a broad level top till we come to Monroe village, where we find 
two, 100 and 150 feet above the river, both of which are continuous a 
mile and a half, with regular southward slopes of ten and twelve feet. 
Occasional remnants of the highest of these are found on both sides 
through Bath and Ryegate; and the lower is well shown through these 
towns, agreeing closely in height on opposite sides of the river. On 
the east side it is continuous for eight miles, from one mile north of 
Monroe to the Narrows near Woodsville, sloping from 545 to 488 feet 
above the sea. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 29 


At Woodsville a great depth of material was brought into the valley 
by the Lower Ammonoosuc and Wells rivers. The former stream has 
cut its channel 200 feet deep through its delta, wide areas of which still 
remain on both sides. An old outlet of Wells river may be seen on its 
north side, one mile above its mouth, occupied at the close of the ice 
period until it cleared away a hundred feet or more of modified drift 
from the pre-glacial rocky bed in which it now flows. A well-marked 
kame occurs here, commencing in Bath half a mile north-west from the 
Narrows. It has been cut through by the river, and appears on the east 
side of the railroad at and above the junction, and again at the south-west 


side of Wells River depot, being more than a mile ae ee 

long. It is composed of coarse gravel and sand, bee ef 

anticlinally stratified, with varying height from & Pe. Pe 

80 to 150 feet above the river. It is well shown + ue @ 2, 

by cuttings, but otherwise might escape notice, as i 455- 

most of it is partially or wholly concealed by the 3 a 

ordinary alluvium. In position, material, and strat- z ae 

ification, this is like the long kame which extends : : 

in this valley from Lyme to Windsor; but in the §% : 

twenty-four miles from Wells River to Lyme no g , 

similar ridge is found. 4 * # 
From Wells river to Wait’s river, at Bradford, g 

the lowest terrace or interval is one half mile to g \ Z 

one mile in width; and the river sweeps in broad = 

curves from side to side between its bordering up- a 

per terraces. By the largest of these bends, called : e 

the Ox-bow, the river traverses two and a half S i ” 

miles to make one half mile of advance, by which . 

a beautiful expanse of interval is added to New- E 

bury. An old channel formerly left this and as Bs eis 

much more on its east side. This ancient course 3 i re 

extended from the north-west end of the Ox-bow e : - 

south-west to the railroad, which it followed to z5 m 

the brook that flows through Newbury village, by  %* 


which it passed east to its present channel. North Haverhill is situated 
on the highest normal terrace, 107 feet above the river and 27 feet higher 


30 SURFACE GEOLOGY, 


than the corresponding terrace opposite, on which Newbury is built. 
This difference may be partly due to the fact that here was one of the 
principal outlets of the melting ice-sheet that continued to cover Moosi- 
lauke and the high water-shed after it had withdrawn from the Con- 
necticut valley. East from North Haverhill, where there are now only 
insignificant brooks, we find an abundance of sand and coarse gravel 
which came from this source. It is disposed in irregular slopes, in some 
portions mounded or ridged, and rising in about one mile 250 feet, beyond 
which the same materials extend nearly level to French pond. Taking 
the road to Haverhill town-house, we pass a ridge of coarse gravel or 
slightly modified drift, which rises from 40 to 100 feet above the village. 
North-east from this there is a nearly level plain of fine alluvium, with 
beds of clay. A short distance farther east we come to a sand ridge, 
which extends about a half mile along the road, rising 80 feet by a gentle 
slope, and then abruptly 75 feet more, like the face of a terrace, to a level 
plain on which the town-house stands, 247 feet above North Haverhill 
and 752 feet above the sea. This plain, its western steep slope, and the 
first ridge below are all of sand, with none of the coarse gravel charac- 
teristic of kames. Similar deposits of fine material reach for a half mile 
on each side of this road, sometimes in level plains of small extent, but 
generally in varying slopes, by which they are continuous from the town- 
house to the upper terrace of the river. 

The remainder of the way to French pond is comparatively level, being 
at first a plain of stratified, coarse-grained sand, which extends north one 
half mile to the brook; thence, for a mile and a half farther, sand or 
coarse rounded gravel extends along the road and on its east side as far 
north as to French pond. Immediately about this pond the modifying 
action of water is not apparent, but the surface is composed of heaped 
and ridged morainic drift, over which the road passes. This material is, 
however, in the main, level; with irregular hollows and depressions of 
only ten to twenty feet. Its rock-fragments are angular, but small in size, 
seldom exceeding two feet. A coarse morainic ridge extends more than 
a mile on the east side of this level alluvial valley, with a height about 
125 feet above it, while on the west rises the precipitous face of Brier 
hill, Three miles south-east are the serrated mountains which extend 
north from Owl’s Head; and nine miles south-east is the high, massive 
ridge of Moosilauke. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 31 


By estimate, French pond is about 770 feet above the sea, and the 
water-shed on the road northward is from 40 to 50 feet higher. This 
hollow, bounded on both sides by high hills, seems to have been for a 
time the outlet of the melting ice at the north, before the way was opened 
westward for the Lower Ammonoosuc river. The glacier which covered 
the mountains at the south-east also contributed to these deposits of 
modified drift, as is shown by the high moraine mentioned, and by others 
three fourths of a mile south from the town-house, at the mouth of a gap 
in the first high range of hills. The highest of these last has been modi- 
fied by a current of water. It presents on the west side a steep escarp- 
ment of clear sand, reaching from 980 to 1020 feet above the sea. At 
the top this changes to gravel, which becomes coarse as we recede from 
the edge of the steep slope; next are large glaciated boulders, heaped 
together with no earth among them, which again present a steep face and 
somewhat level top 1050 feet above the sea. These rest at the east 
against the hillside. On the north-west nothing intervenes to the town- 
house and North Haverhill, 300 and 550 feet below, where we find the 
sand and clay which were brought down by these glacial streams. 

At Haverhill there are only scanty remains of modified drift above 
the interval, which is nearly a mile wide. The highest terrace, best 
shown on the Vermont side, is 80 feet above the river; enough of it is 
left on the east side to indicate that it was once continuous across the 
valley. Hall’s brook and Oliverian brook, which have their mouths here 
opposite to each other, have brought down large amounts of modified 
drift, which is deposited along the lower portion of their course. On the 
former this slopes in one mile to 125 feet above the upper terrace of the 
Connecticut. On the east side only slight vestiges of this terrace are 
found, and we have a direct rise of 220 feet from the interval to the mod- 
ified drift of Oliverian brook, which thus commences at a greater height 
than is reached in the first mile on Hall’s brook. In two miles this 
slopes upward 100 feet, or to 340 feet above the river, being well shown 
all the way, and at one place nearly a mile wide. These streams are both 
of large size, but the deposits along their course cannot be attributed 
to their ordinary action, any more than the modified drift east of North 
Haverhill is due to the brooks there. All these deposits are plainly of 
the same date and from one cause,—the melting of the ice-sheet. 


32 SURFACE GEOLOGY. 


The village of Haverhill is situated on a high, smoothly rounded, ter- 
race-like area of till. This slopes steeply towards the river, but very 
slightly to the north and north-east, and extends nearly level for half a 
mile south-east to the foot of Catamount hill, and for two miles south- 
ward along the Piermont road. A large proportion of the boulders in 
this till are glaciated, sometimes preserving distinct striz. The prevail- 
ing size is less than three feet; but rocks of five or six feet diameter, or 
even larger, also occur. These are found most rarely over the south part 
of this area in Piermont, where the abundant rounded or glaciated peb- 
bles exposed by the channels of streams present the appearance of coarse 
kame-like gravel. At about one fourth mile south- 
west from Haverhill village a gully recently made on 


E. 
400 ft 
above sea, 


a previously smooth slope, at a height about 175 feet 


above the river, and consequéntly much above its 
highest terrace, and 75 feet below the village, showed 
15 feet of modified drift resting on till. The surface 
was 3 feet of coarse gravel, which was succeeded by 


Length, 1$ miles. 


12 feet of interstratified fine gravel and sand, oblique- 
ly bedded. The stratification here sloped with the 
present surface, about 10 feet in 100, with the ob- 
liquely bedded portions steeper in the same direc- 
tion. Similar sections of overlying modified drift are 
shown in many places west and south from Haver- 
hill, but the north and east parts of this area consist 
only of till This is the ground-moraine of the ice- 
sheet, peculiarly massed here in very large amount, 


Piermont 
depot. 


resembling the massive rounded hills of the same 
material, which are abundant near the coast. On the 
opposite side of the river we find the extensive slope, 
which’ rises south from Hall’s brook, also composed 
of till with no outcropping ledges. 

In Piermont, opposite Bradford village, the modi- 
fied drift is divided by ledgy hills close to the river 
into two belts, the eastern of which has a height of 
478 feet above the sea, or about 90 above the river, where it departs 
from the main valley. This extends along Gully brook, sloping in two 


Fig. 5.—SECTION IN BRADFORD AND PIERMONT. 


Delta of 
Wait’s river. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 33 


miles to 460 feet, nearly representing in height the normal upper terrace 
of Connecticut river. We find this normal line shown on the Vermont 
side by a nearly constant height of this terrace, varying between 470 and 
460 feet for more than seven miles, from above Hall’s brook to the south 
line of Bradford. 

Delta of Watt's River. We thus exclude, on the north from Bradford 
village, the principal plain, which is from 10 to 15 feet above this upper 
terrace, being highest at its south end, and the still higher terrace of the 
fair-ground, and on the south the conspicuous remnants of the ancient 
delta of Wait’s river, which are more than 100 feet above the Con- 
necticut normal line. These terraces have all been deposited by Wait’s 
river, which seems to have first thrust its high delta into the main valley, 
whose strong currents undermined and removed a large portion, leaving 
the rest with a steep escarpment; afterwards most of this delta was chan- 
nelled out by its parent stream and carried down into the main valley, by 
which the terraces north of Bradford were formed ; and, lastly, it has also 
swept out a large amount of the upper Connecticut terrace east of the 
village. 

For a mile from the mouth of Wait’s river southward, the number of 
terraces is multiplied to five or six in ascending 75 feet from the river to 
the wide upper plain. These furnish the best examples seen on the Con- 
necticut of glacis terraces, sloping steeply towards the river and gently 
away from it in a wave-like series, with from 5 to 10 feet difference in the 
height of successive crests, 

Eastman’s brook is the source of the modified drift on which Piermont 
village is built. This delta rises in two thirds of a mile nearly 200 feet 
above our normal line. 

Delta of Facob’s Brook. We now encounter in Fairlee and Orford one 
of the most difficult problems presented on this river, in the abundant 
deposit of alluvial sand, which, between Sawyer’s mountain and Morey’s 
mountain, forms a high plateau, whose eastern edge overlooks the river, 
while its western slope descends towards Fairlee pond. The highest por- 
tion of this alluvium is 190 feet above the river and 155 feet above the 
pond. The highest normal terrace is well shown through these towns, 
varying from 75 to 55 feet above the river, or from 455 to 435 feet above 


the sea. This terrace appears in Fairlee, at its north line, south-west of 
VOL. Il. 5 


34 SURFACE GEOLOGY. 


Shaw’s mountain; next east below the plateau; southward from Fairlee 
village and pond; and at Ely station. In Orford it is wide north-west of 
Soapstone mountain, and the river road runs upon it south to Jacob’s 
brook; in the village it is the terrace at the east side of the street; and 
from near the mouth of Sawyer’s brook it averages one half mile wide for 
three miles south, leaving the river at the north line of Lyme, and extend- 
ing along Clay brook nearly level to within one mile of Post pond. All 
the modified drift above this regular terrace, embracing the plateau east 
of Fairlee pond, the high terrace in Orford, which begins at the south foot 
of Soapstone mountain, and the high remnants at each side of Jacob’s 
brook, must be referred to a common origin, being portions of an im- 
mense deposit brought down in the Champlain period by Jacob’s brook. 

This stream drains a large area west and north-west from Cuba and 
Smart’s mountains, flowing through Orfordville into the Connecticut by a 
north-west course. An uncommon abundance of fine material was sup- 
plied from the melting glacier over this area, and the northward flood 
which transported it was turned up the valley by the vertical wall of 
Morey’s mountain. For a time the accumulation was too great to be 
cleared away by the current of the main valley, which was filled by this 
deposit north to Soapstone and Sawyer’s mountains. A wide avenue was 
next cut through this barrier by the Connecticut, which did not complete 
till a later date the deposition of its own flood-plain, the remains of which 
we have called its highest normal terrace. 

A few measurements of this remarkable tributary deposit will indicate 
its extent and depth. It filled the valley for more than two miles north 
from Orford, averaging a mile in width. The ordinary height of the river 
here is 383 feet above the sea. The highest point of the plateau in Fair- 
lee, a mile and a half north from the mouth of Jacob’s brook, is 575 ; 
the lowest point where the current swept west across this plateau, one 
third of a mile south of the former, is 532; on the east side, a mile and 
a half north from the mouth of the brook, it is 530; and close at its 
north side, 565. Along its course we also find a large amount of modi- 
fied drift, rising in a mile and a half to 690, or more than 100 feet 
above the comparatively level barrier which it had thrown across the 
Connecticut valley. 

A peculiarly contorted band of clay (Fig. 6), in a layer of clayey sand, 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 35 


with regular strata of sand exposed for several feet both above and below, 
was seen on the north side of a cart-road which ascends the east bluff of 
the Fairlee plateau, opposite the house of William Childs. 

The shores of Fairlee pond are mostly rugged ledgy hills, and scarcely 
any alluvium has reached them, either from the plateau of Jacob's brook 
or from inflowing 
streams. This 
pond is 35 feet 
above the river, 


and is from 40 Fig. 6.—FoLDED LAYER OF CLAY IN HORIZONTALLY STRATI- 
to 45 feet in its FIED SAND, FAIRLEE, VT. Scale, 1 inch—=10 feet. 
greatest depth, the bottom being principally sand. It seems not to have 
been filled with alluvium, simply because it was not in the path of the 
current; and the steep escarpment of the plain bordering its south end 
is probably due to its undermining waves. Several glacis terraces were 
noted south-west of Ely station. 

In Thetford and Lyme we come to an abrupt change in the height of 
the upper terrace-plain. We have seen this line descend, in 33 miles 
between the mouth of Passumpsic river and the south line of Orford, 
from 650 to 440 feet above the sea, gradually declining from 190 to only 
60 feet above the river. At North Thetford this line of the highest ter- 
race suddenly rises to 525, and in a mile and a half farther south to 545 
feet. This formation is well shown through Thetford, with remnants in 
Lyme, and continues well developed and nearly level for twenty-five miles 
to Windsor, varying from 560 to 500 feet above the sea, and from 150 to 
220 feet above the river. It forms extensive terraces or plains on one 
or both sides along this whole distance, and is clearly the original flood- 
plain of the river. Frequent delta-terraces rise above it, sometimes 100 
feet higher, being more than 300 feet above the present river channel. 
It is a notable coincidence, that along this same distance we have a con- 
tinuous kame, occupying the centre of the valley, commonly rising some- 
what above the highest plain, but not seldom entirely covered by it. 
Superposition and conformable stratification show the fine material of 
the terrace-plain to have been deposited upon this kame or gravel ridge, 
which beforehand extended like a windrow along the empty valley. To 
the south from Windsor the highest terrace shows a somewhat regular 


36 SURFACE GEOLOGY, 


slope, descending with the river, and preserving a height about 150 feet 
above it. 

This high and continuous flood-plain, extending from Thetford to Mas- 
sachusetts line, seems to have been formed during a gradual and slow 
melting of the ice along this distance. It would appear that the greater 
part of the depth of ice, as far northward as to the Passumpsic river, had 
been melted in the last part of this time, sending down its floods laden 
with gravel to form the kame. A comparatively shallow mantle of ice 
remained, and when the melting advanced to the north from Thetford 
and Lyme this disappeared too rapidly to give time for the formation of 
a kame, or the deposition of a high flood-plain. 

At the north line of Thetford, near Ely station, the highest terrace is 
435 feet above the sea, or 55 feet above the river. This is the south end 
of the continuous descending slope from the mouth of Passumpsic river. 
The first intimation of change is a high terrace, which rises from 475 to 
545 feet in going from one mile north to one mile and a half south of 
North Thetford. Opposite to this place in Lyme the alluvium does not 
appear as usual in distinct terraces, but lies in a slope rising from 400 to 
450, and at one mile north to 490 feet. South from North Thetford the 
high plain averages one half mile wide for eight miles, extending half 
way through the town of Norwich. Along this distance in Lyme and 
Hanover only narrow terraces of corresponding height remain. 

Child’s pond, situated on the high plain one third of a mile north of 
East Thetford, is worthy of notice. No terrace occurs here below the 
plain, which has been so undermined as to slope from its top to the river 
at an angle of 45°, excepting only the width of the railroad bed built on 
its side near the bottom. Eighty-five feet back from the edge of this 
plain, with a road between, is the pond, occupying some two acres, 142 
feet above the river, and by our soundings 40 feet deep. Its range from 
high to low water is said to be one foot and a half, with outlet to the west, 
but no inlet; and its surface is only from two to five feet below the plain 
on its east and south-east sides against the river. The clayey character 
of this alluvium is shown by the impervious bank which holds in the 
pond. The circumstance that only so narrow a width intervenes between 
the pond and its edge is not specially remarkable, as this plain was origi- 
nally continuous across the valley, all its east portion having been exca- 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 37 


vated by the river. The question which we see no satisfactory way to 
answer is, How came the hollow which contains the pond to be formed 
or left vacant, when the material of the otherwise nearly level plain was 
deposited? Probably it marks the site of a mass of ice, broken from the 
glacier, brought down by the flood, and finally stranded at this spot. The 
principal objection to this hypothesis is the rapidity of deposition required. 

A large amount of modified drift has been brought down by Grant’s 
brook, forming the plain on which Lyme village is built. The common 
has a slope of fifteen feet, and in a short distance farther east the same 
deposit rises eighty feet more, to 635 feet above the sea, or go feet 
higher than the water-shed between the village and Post pond. 

Anctent River-bed. In Norwich occurs the most interesting example 
seen by us of a well-marked ancient river-bed high above its present 
level. This extends two miles from Pompanoosuc river, one third mile 
above its mouth, to the bend of Connecticut river a half mile south of 
Tilden pond, which lies in a depression of this old channel. Its highest 
point, from which there is a gradual descent both ways, is 520 feet above 
the sea, or 145 feet above the river. West and south-west from this point 
is a plain, from 30 to 40 feet higher; at the north-west the alluvium forms 
a delta-like slope with no level top. South-west from Tilden pond the 
original high plain has been excavated by springs and small streams to a 
very irregular surface of hillocks and ridges. On the east side of this 
ancient channel is the steep gravel kame, which for a while turned the 
Pompanoosuc river in this course, till a direct passage was cut through 
its ridge. 

Norwich village, 525 feet above the sea, is situated on a terrace-plain 
of Bloody brook, which extends three fourths of a mile above the village, 


Hanover Ag. Coll. Delta of 
common. farm, Mink Br. 


w Terrace of Bloody Br., os 
a 545- 500. 564. 


wn, ise] 
8 ~=- Norwich village, 52s. g g 


Fig. 7.—SECTION IN NORWICH AND HAROvER. “Length, 3 miles. sea, 


rising 30 feet. At one mile south the modified drift on the Vermont side 
is interrupted by a ledgy hill. 
Two miles north of Hanover the Connecticut river has cut through the 


38 SURFACE GEOLOGY. 


kame, and thence flows close on its west side to White River falls. 
Along this distance of four miles we find the high plain well developed 
in New Hampshire, averaging three fourths of a mile wide. Hanover 
common, 545 feet above the sea and 172 above the river, represents its 
greatest altitude. Westward, a gradual slope descends 30 feet in one 
third mile to the kame; one third mile east the farm of the agricultural 
et nan college is 45 feet lower than the 

150-259. common; and we have the same 

height one mile south, at the high- 
. est portion of the road to West 


Horizontally 
stratified sand. 


Gravel. 


Lebanon. Observatory hill, and 
others in Norwich and Lebanon, 


Fig. 8.—SEcTion In DeLTa oF Minx are examples of outcropping ledges 


7a Ga Hanover. Scale,tinch=20 and till, surrounded by alluvium. 
eet. ki 
The lower sand shows the usual stratification of the Half a mile south-east from Han- 


outer part of a delta, dipping towards the open y 
ies A current of water has eroded a is ses 5a delta 20 to 4° feet higher 
of this, bringing a bed of gravel, upon which rests § than the common has been brought 
a later deposit of sand. i ‘ 

down by Mink brook, which, west 


from this point, has also excavated a large amount from the plain. On 


the roads to Lyme and West Lebanon such erosion as this exposes a 
clayey stratum, noticeable in the spring by remaining muddy after all the 
rest of the road has become settled and dry. Two miles north of Hano- 
ver this stratum appears from 488 to 503 feet above the sea, most nota- 
bly at the height of 495; a mile and a half south, at the north side of the 
Vale of Tempe, its height is 482; on the south side, 479 to 482; a mile 
farther south, on the north side of Mink brook, it appears from 503 to 
480, being most marked at 485; on its south side it occurs at two points, 
with heights 470 and 478 to 483, the last being most prominent; and 
about a mile farther south, at the descent just before the turn-off to the 
falls, it is very noticeable, with about the same height. It also occurs in 
Vermont at a corresponding height, just below the top of the ascent be- 
tween the depot and Norwich village. This extensive and nearly level 
stratum shows that deposition took place gradually and at the same time 
over this whole area. 

In digging the first well at Hanover (near the residence of Prof. H. E. 
Parker) a large log was found in this alluvium 40 feet below the surface, 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 39 


but no prospect of water, which caused this site, selected for the buildings 
of Dartmouth college, to be abandoned, and led to their location farther east, 
upon coarse glacial drift. This log was at nearly the same level with the 
clayey stratum described, and adds to our knowledge of the conditions 
which prevailed at the time of its deposition. The glacial age had here 
been succeeded by a temperate climate, under which forests grew again 
upon the land; and floods, sent out freighted from the melting ice-sheet, 
which still remained farther north and on the highlands, brought down 
drift-wood to be buried with this alluvium. It was not till long after this 
that the river ceased its work of accumulation and began to cut its pres- 
ent channel. 

Veins of segregation in sand, attended in some instances by a slight 
displacement or fault, are well displayed at the present time by the fresh 


Depression, Kame. River. 


g Fault. Faults. 
Ww 


3 inches to x foot. 515. 373- 


Segregated veins 

in lower portion. 
oan 

375 ft. above sea. a ak a Ci ae nla 


Fig. 9.—SECTION ON SOUTH SIDE OF ROAD, EAST FROM LEDYARD BRIDGE, 
HANOVER. Length, about 700 feet. 


washing away of the bank, a portion of the high plain, on the south side 
of the road between Hanover and the depot. These veins abound for 200 
feet or so east from the kame, a good section of which is also shown here; 
they are in somewhat obliquely stratified sand, which inclines conformably 
where it overlies the side of the kame. 

Between Hanover and White River Junction the Connecticut descends 
40 feet, principally at White River falls (vol. i, pp. 302* and 319), situ- 
ated two miles above the mouth of White river, and three miles above 
that of Mascomy river. An illustration of the terraces on the west side 
of these falls, as seen from Colburn hill in Lebanon, appears in Dana’s 
Manual of Geology.+ The upper terrace is wide, with a height 525 feet 


* The survey for this map was made when the river was above its ordinary height, which is at Hanover 373 
and at White River Junction 333 feet above the sea. 


+ First edition, p. 548; second edition, p. 544. 


40 SURFACE GEOLOGY. 


above the sea, or 190 feet above the river at the foot of the falls. The 
middle terrace here rises in going south from 435 to 455 feet; and its 
material, well shown by a long railroad cut a sixth of a mile west of the 
upper falls, is mainly fine and coarse gravel, quite in contrast with the more 
common sand and clay. This difference in material is clearly explained, 
however, by a gap in the kame, which has been cut through and swept 
away by the river above the falls and on the northswest side of this ter- 
race, which has been formed from it. Tributary streams have also often 
brought down coarse gravel deposits, forming deltas or contributing to 
the normal high terrace-plain, which on this account is often difficult to 
be precisely distinguished. Mascomy river, in Lebanon, and Little 
Sugar river, at North Charlestown, especially, have brought in these 
coarse deposits in large amount, changing the character of all the modi- 
fied drift to a mile below their mouths. 

A quarter of a mile south-west from White River Junction we find an 
ancient bed of White river, similar in position and height, and formed 
and deserted under the same causes with that of Pompanoosuc river (p. 
37). This is a nearly level depression, 300 to 400 feet wide, 25 feet be- 
low the alluvial plain on the west, and 60 feet below the gravel ridge or 
kame on the east. Its height is 154 feet above the river on the north, or 
487 feet above the sea. It descends only three feet in going 1,000 feet 
to the south, where the high plain in which it was formed, and the ridge 
which was its eastern barrier, have both been washed away. 

Through Hartford and Hartland the upper terrace is well exhibited, of 
a normal height 525 to 500 feet above the sea, or nearly 200 feet above 


Hartland ro} 
g depot. Kame. g Bs 


”n 421. 550. 0) 


5 Lull’s ¢ 
& Delta. brook. & 


559. 


Fig. 10.—SECTION IN HARTLAND AND PLAINFIELD. Length, 14 miles. 


the river, and reaching one third to one mile back from it; but in several 
places this is broken by hills of ledge or till, isolated or extending across 
it nearly to the river. Its normal height is increased 40 to 80 feet by 


Plate Ill. 


% 


SHOWING 


the Modified Drift of 
GONNECTICUT RIVER. | 


——_—__ 
1 z 3 An 
SCALE of MILES. 


ee 


TASTIQUIT 
IM. yi 


or 3 
= WN 


This border is the true meridian for all the maps enclosed. 
i 


HELIOTYPE. 


‘MODIFIED DRIFT ALONG CONNECTICUT RIVER. 4! 


tributary alluvium for two miles south from Quechee river, and for one 
mile south from Lull’s brook. A level-topped delta, on both sides of the 
latter at its opening into the main valley just south of Hartland village, 
is 320 feet above the river, which is less than a mile distant. This high 
delta is terminated by a steep slope of from 25 to 40 feet, below which, at 
the south, there is no line of separation between the additions from this 
brook and the ordinary highest terrace; but the whole shows an irregular 
surface of smoothly rounded hills and hollows, formed by small streams. 
Similar erosion has taken place west of North Hartland. This cause has 
frequently destroyed the true shape of these high plains, originally level, 
and bounded by a steep escarpment; instead of which we now find slop- 
ing buttresses, ravines, and scattered knolls and ridges, in a confusion 
quite opposite to the beautiful system and regular form of the terraces. 

In Lebanon and Cornish steep hills of till or ledge come quite to the 
river at the lower descent of White River falls and opposite Windsor 
village; in Plainfield the hill comes near the river at Sumner’s falls, and 
opposite Hartland village the alluvium is thus reduced to a very narrow 
strip for a mile. No very broad development of modified drift occurs in 
either of these towns. Of the original high plain we find only scanty 
remnants; the intermediate terraces are present, but as usual of small 
width ; of the lowest terrace we have at the mouth of Mascomy river the 
largest expanse that occurs in the twenty-four miles along which the 
kame remains, but this comprises only about half a square mile, and it is 
mostly above the reach of high water. 

The readiness with which the fine, loose modified drift may be chan- 
nelled out by rivulets or springs is often shown by long, deep gullies 
extending from the edge of a terrace directly across some field, whose 
level surface was never before marked by any water-course or hollow. 
Such a gully, fifteen rods long, two to four rods wide, and fifty feet deep, 
has recently been made in a terrace 100 feet above the river, at a point 
two miles south of West Lebanon, on the east side of the river road, 
which was undermined and turned aside by it. 

Dunes. Near the south line of Lebanon, east of Sumner’s falls in 
Plainfield, and at several places in Cornish, we find banks of sand, or 
dunes, destitute of vegetation, and blown in drifts by the wind. These 


vary in height from a few feet to 100 feet above the highest terrace, from 
VOL. 1. 6 


42 SURFACE GEOLOGY. 


which they appear to have been carried up by the prevailing north-west. 
winds. Southward they are found in many places on the east side of this 
valley, but none were seen in Vermont. 

Deltas. A large amount of modified drift occurs on Blow-me-down 
brook. Three miles from its highest source, where the road crosses 


23 = ny Se See 
Brie PRers 2s . 
a y BS 
is Ey] e 
Sy | Hees 

so NR Earl 

Mice os ae i 
ere fee LES 


oS Serene ae! 
SS 8 ° 
Fig. 11.—SAND DUNE, NEAR THE SOUTH LINE OF LEBANON. 


Croydon mountain, it has formed the plain of Cornish Flat, 855 feet above 
the sea, and six miles lower that of Plainfield village, 520 feet above the 
sea, with an older deposit 30 feet higher, at the north end of the village. 
Two miles farther down, where this stream opens into the broad valley, it 
has formed a delta of irregular slope from 512 to 420 feet. These trib- 
utary deposits often throw light on the history of the modified drift of the 
main river. We have seen that the deltas north of the continuous kame, 
as of Wait’s river at Bradford, and Jacob’s brook at Orford, were deposited 
before the completion of the original flood-plain of the Connecticut; but 
the deltas of Quechee river and Lull’s brook appear to have been brought 
down at about the same time with this upper terrace, which is notably 
increased in height by them for a considerable distance; while the long 
sloping delta of Blow-me-down brook, covering a square mile and descend- 
ing to nearly 100 feet below the normal highest plain, seems to be of 
a date subsequent to its formation and partial removal by the river. A 
conspicuous dune at the east side of this delta, derived from it and from 
the original high plain, is 610 feet above the sea, or 100 feet higher than 
the deposits from which it was blown. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 43 


The Kame of Connecticut Valley. 


From Lyme to Windsor we find a continuous gravel ridge or kame, 
extending twenty-four miles along the middle and lowest portion of this 
valley, with its top from 100 to 250 feet above the river, or from 500 to 
600 feet above the sea. Its material is gravel and sand, in irregular, 
obliquely-bedded layers, always showing an inclined, and in most cases 
a distinctly anticlinal or arched, stratification. The sand is usually coarse 
and sharp, well suited for masons’ use. It occurs in layers of varying 
thickness up to one or two feet, but sometimes it is wholly wanting. The 
gravel, which always forms the principal part of the ridge, varies in coarse- 
ness, from layers with pebbles only one or two inches in diameter, to por- 
tions where the largest measure one and a half or two feet. The finer 
kinds prevail; and the channels of brooks cutting through the ridge fre- 
quently show no pebbles exceeding one foot in size. All the materials of 
this kame, and of its remnants along this valley, are plainly water-worn 
and stratified. 

Large and unworn boulders, which could not have been brought in the 
same way with the gravel and sand, occur very rarely upon or in the Con- 
necticut kame. Except at its south termination, the only instance of this 
discovered was three fourths of a mile south of Pompanoosuc river, at 
the point where the kame reaches its greatest height above the sea. Two 
angular boulders, each of five feet dimension, were found here at the top 
of the ridge, one lying on the surface, and the other partly imbedded. 
This place was covered with a thick growth of sapling white pines. Sev- 
eral miles at least of journey on foot along the top of this ridge, and the 
examination of many sections where the river or its tributaries have cut 
through it, failed to reveal other boulders of this kind. 

One or both sides of this kame are generally covered by the alluvium 
of the upper terrace, which plainly was of later deposition; but the top 
usually projects in a long, rounded ridge, 10 to 30 feet above the adjoin- 
ing highest plain. At one place, east of Hartland depot, this plain has 
been swept away from both sides, and the kame forms a conspicuous, 
steep ridge 125 feet in height. Wherever it is exposed, it is readily rec- 
ognized by the pebbles which strew its surface, and which are very rarely 
found in the ordinary modified drift of the valley. 


44 SURFACE GEOLOGY, 


The most important feature of this kame, if we compare it with others 
in New Hampshire, is, that along its entire extent it constitutes a single 
continuous ridge, which runs by a very direct course nearly in the middle 
of the valley, having no outlying spurs, branches, parallel ridges, or scat- 
tered hillocks of the same material associated with it. The kames in the 
Merrimack valley and in eastern New Hampshire also average much 
coarser, and more frequently contain angular boulders, while in some 
places they show a gradual transition from sand and water-worn gravel 
to unmodified moraines. 

This remarkable ridge shows the course of the glacial river by which 
the floods from the melting ice, laden with gravel, sand, and clay, found 
their way between ice-walls to the open valley below. All the material 
which was thus brought down was probably gathered from the melting 
surface of the ice-sheet; and the pebbles were rounded in being carried 
along by its streams. Near the mouth of the channel in which these 
waters flowed, a portion of their gravel and sand was deposited with the 
alternation of summer and winter. Elsewhere, kames may have been 
formed by rivers beneath the ice-sheet; and when many boulders are 
contained in them, or found on their surface, they seem to be most read- 
ily explained by supposing them dropped from a melting roof of ice. It 
is at least plain, that if any kames have been formed under the ice, they 
must contain many boulders derived from this source. In nearly all the 
kames of New Hampshire it seems more probable that the angular mate- 
rials and large boulders, which we find associated with these water-worn 
deposits, were brought by the same currents, frequently in floating masses 
of ice. Their infrequency here puts it beyond doubt that the kame of 
Connecticut valley was formed in an open ice-channel. It is probable 
that this did not extend at one time over the whole distance where we 
find the kame, but that it was gradually formed as the melting advanced 
northward, which was at so slow a pace that for a long time walls of ice 
enclosed the deposits of the glacial river. After these walls melted, the 
gravel and sand remained in a long, high ridge, which became nearly 
covered by the subsequent slow deposition of the high alluvial plain. 

When the river entered upon the work of excavating its present chan- 
nel in the alluvium, the kame was a barrier which confined erosion to the 
area on one of its sides and protected its opposite side; so that this ridge 


MODIFIED DRIFT ALONG CONNECTICUT RIVER, 45 


of gravel often forms the escarpment of a high plain, with the river flow- 
ing at its base. On this account we find the upper terrace occupying a 
greater width along the course of the kame than it averages elsewhere in 
this valley. 

In calling this kame continuous from Lyme to Windsor, it is not meant 
to imply that it is now entire, since it has been frequently cut through 
and considerable portions swept away by the main river and by tributary 


THETFORD. NORWICH. 
East é ia a Pompanoosuc 5 
Thetford. & 8 2 g 


river, 


HANOVER. 28 a] LEBANON. HARTFORD. 
Connecticut oo Ss © § oS § & Mink Connecticut White River 
river, RY BB ~~ & Br. river, falls. 


HARTFORD. LEBANON. HARTLAND. 
; Mascomy o Mouth of 


Ke) 
White river. S$ Conn.R. river. 


5. 


Plainfield. Cornish, © WINDSOR. 


Fig. 12.—PROFILE OF THE KAME OF CONNECTICUT VALLEY (24 miles; vertical 
scale, I inch=800 feet). 


The dotted line marks a height 300 feet above the sea, and the line next above represents the river. 


streams; but that so much of it remains as to make it certain that it 
originally formed an unbroken ridge. The portions now separated by 
gaps always lie in a continuous line. 

The first evidence that we find of this ridge is a coarse gravel deposit 
on the south side of a hill in Lyme, one mile north of the mouth of 
Grant’s brook. For about one mile south from this point it has been 
carried away by the river. It then commences about one third of a 
mile south-west of the railroad station in Thetford, and thence extends 
southward with the profile shown in Fig. 12. It is nearly straight four 
miles to the mouth of Pompanoosuc river, which has cut through it, but 


46 SURFACE GEOLOGY. 


was at first turned south by it, as shown by an ancient river-bed (p. 37): 
There is a slight bend in the kame at this point, but it continues with 
very nearly the same course eleven and a half miles farther to the south 
line of Lebanon, where it bends with the valley. It has no long gaps in 
the first half of this distance above White River falls. The Connecticut 
has formed for itself a more irregular course than this of the old glacial 
river, first flowing with the kame at a considerable but varying distance 
on its west side; then, about two miles south of Pompanoosuc river, it 
cuts through this ridge, which thence through Hanover and Lebanon 
forms its high east bank to these falls. Gaps have been made in Han- 
over at the Vale of Tempe, at Webster’s vale, at the road to the bridge, 
and by Mink brook. The second and third places are outlets of long 
gullies, which now have no running streams. 

At White River falls one mile of the kame has been removed by the 
river, giving coarse materials for terraces below (p. 40). It appears next 
in Hartford, where it is cut through by White river, south of which a 
good section of it is shown only a stone’s throw from the Junction depot. 
Next, about a mile and a half has been swept away by the Connecticut, 
across the area now occupied by the low terrace at the mouth of Mas- 
comy river. A remnant is found in the south part of Lebanon, but it is 
soon crossed again by the river, and then continues a mile on the west 
side from the north line of Hartland to the mouth of the Quechee river. 
From this point, for two miles to Sumner’s falls, it has been washed away 
by the Connecticut, which probably occupies nearly the former place of 
the kame. Thence it forms a high ridge close upon the west side of the 
river for nearly three miles to the mouth of Lull’s brook. Next a rem- 
nant appears on the east side, at the line between Plainfield and Cornish, 
south of which it is cut through by the Connecticut for the seventh and 
last time. A section of it is exposed here on the south-west side of the 
river and railroad, where the largest pebbles seen were a foot in diame- 
ter. Thence it is well shown for a third of a mile south, reaching some- 
what above the highest terrace, but with a natural gap 4o feet below its 
general level where it is crossed by the road. It terminates a short dis- 
tance farther south-west, resting upon the side of a ledgy hill, about one 
mile north-west from Windsor village. The portion south of the road 
has a few boulders on its surface, which takes the form of a terrace. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 47 


Probably a similar gravel ridge once existed along the valley south- 
ward, though now shown by only a few fragments; and it seems proper 
to add here whatever facts we have on this subject. Gravel, which is 
unmistakably that of the kame, was seen in the west part of Windsor 
village, exposed by excavation at a street corner some 500 to 600 feet 
north-west from the dam of Ascutney pond. Here all of the kame that 
was above the street has suffered erosion, and all else seen was fine allu- 
vium. On the east side of Ascutney pond we find a high, nearly level- 
topped area of kame-like gravel. This extends from north to south about 
three fourths of a mile, being one eighth of a mile wide, with a steep 
escarpment on each side. This seems to be a kame deposit, wider than 
usual, and resembling the high plains or broad ridges of the same origin 
about Dover and southward near the coast. The south end of this de- 
posit rests upon the north end of a ledgy hill. A mile and a half farther 
south we find distinct remains of the kame close upon the west side of 
the river road, extending about one mile with equal portions in Windsor 
and Weathersfield. This forms the east border of a high terrace, both 
kame and terrace being 150 to 170 feet above the river. The material 
of this kame is plainly shown by excavations made for repair of the road, 
and it is like that which uniformly prevails in the long range from Lyme 
to Windsor. Thus we find frequent gravel deposits which are probably 
remnants of a former kame along the first five miles south from the end 
of the undoubtedly continuous range. It is noticeable that here the 
kame was near the’ west side of the valley, with its continuity broken 
by hills. 

In the next eleven miles no indications of the kame were seen. It is 
then quite well shown for one mile in Charlestown, first appearing where 
the railroad cuts the high terrace south of Beaver meadow. This exposes 
a section of the underlying kame, and between Springfield station and 
the Cheshire bridge it forms a gravel hill, with a height in both places 
130 feet above the river, or 420 feet above the sea. Eight miles inter- 
vene before we find its next remnant, which is a pine-covered plateau, 
used as a picnic ground, in the north part of Bellows Falls village. This 
is 75 feet above the streets that surround it, 112 feet above the river at 
the head of the falls, and 395 feet above the sea. At its north end a 
section is exposed, which shows this to be a portion of a kame by its 


48 SURFACE GEOLOGY. 


material, which is the characteristic coarse gravel, and by its anticlinal 
stratification. The next fifteen miles afforded no evidence of the kame. 
We then find three remnants of it in six miles, and below these nothing 
in the following fifteen miles, or to the end of our journey, which extended 
through Northfield, Mass. The first of these remnants was near the 
south-west corner of Westmoreland, 158 feet above the river and 370 feet 
above the sea. The second was a short distance south-west from Dum- 
merston station, 215 feet above the river and 425 above the sea. The 
river has swept this away at its south end, and the railroad is here built 
across its terminal slope, which shows a fine anticlinal stratification. The 
most southern portion of the kame found remaining in this valley is at the 
north side of West river, lying on ledges between the railroad and the 
highway, where we have a well-defined gravel ridge 160 feet above the 
river and 360 feet above the sea. 

These peculiar deposits, similar in material and stratification with the 
kame that extends from Lyme to Windsor, were plainly once more exten- 
sive than now, and probably are portions of an originally continuous ridge. 
Long gaps have been washed away in the southern half of the range, from 
Lyme to Windsor; and farther south the river has left only scanty rem- 
nants of this oldest modified drift of its valley. 


Returning now to the later deposits, which have been shaped by the 
river into terraces, we will begin where we left them, at Cornish and 
Windsor. The original highest flood-plain of the river in these towns 
and through Claremont and Weathersfield seems to have sloped from 500 
to 450 feet above the sea. The river from Windsor to Bellows Falls, 26 
miles, has a very gentle descent from 304 to 283 feet above the sea. 
Hence it will be sufficient in this distance to state only heights above the 
sea, from which that above the river may be easily determined. 

The terraces of Windsor village are very interesting. That at the 
depot and railroad is 330 feet above the sea; of the post-office, 354; of 
the street leading west past the state prison, 382 to 397, rising 15 feet in 
going a half mile away from the river. The last remains now in the form 
of an isthmus, having been channelled out by the river on the north side 
of this street to a depth of 60 feet, and to the same amount on the south 
side by Mill brook. The highest terrace, increased by a tributary, is 
shown farther west. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 49. 


The railroad in Cornish and to within one mile of West Claremont, or 
for a distance of four miles, is built on one continuous terrace, from one 
sixth to one third of a mile wide, and sloping in this width some twenty 
feet towards the river. The west side of this terrace has a height of from 
360 to 350 feet. A terrace of corresponding height extends nearly the 
whole distance opposite to this on the Vermont side. A narrow belt of 
interval is found much of the way between these terraces and the river, 
but for the last mile, at the north corners of Claremont and Weathersfield, 
they are separated only by the channel. These are plainly the remains 
of a former flood-plain, intermediate between those of the Champlain 
period and of the present time. 

Several hills of ledge and till, entirely surrounded by modified drift, 
occur in this part of the valley. One of these, in Windsor, turns Mill 
brook north into Ascutney pond. Another occurs in Weathersfield, 
about one mile south of Ascutneyville. The largest of them is Barber’s 
mountain in Claremont, which occupies an area more than two miles long 
by one mile wide, and reaches an altitude of 950 feet above the sea. This 
has smooth slopes of till on the north and east, but presents abrupt ledges 
on the west and south. It stands directly in the line of the river’s course, 
so that as it is approached it seems at first to form a barrier across the 
valley. The Connecticut has always flowed by its present detour on the 
west side of this mountain. At its north end a remnant of the original 
high flood-plain is preserved, being 440 feet above the sea; and in Ver- 
mont this upper terrace is well shown for half a mile farther south. It is 
then wanting on the west side of the mountain and for more than a mile 
in Vermont, but reappears at its south end on both sides of the river, 
being continuous on the west side to the north line of Springfield. 
Scarcely any alluvium remains at the west foot of the mountain. A very 
narrow strip, however, extends for a mile along the river's edge, notable 
for its slope of twenty feet in this distance from 325 to 305 feet above 
the sea. The opposite terrace in Weathersfield, about 340 feet in height, 
extends more than two miles, with a nearly uniform width of one sixth of 
a mile, west of which rises a high steep hill. 

The high alluvium on the east side of Barber’s mountain is the product 
of Sugar river, and while it was being deposited the Connecticut flowed 


in its present course. This is shown by the height and configuration of 
VOL, II. 7 , 


50 SURFACE GEOLOGY. 


its surface, which tell its origin and mode of deposit. The railroad passes 
by this route, and the portion in which we are interested is from Sugar 
river to Claremont junction. East of the railroad Trisback hill rises 850 
feet above the sea. This obstacle turns back the course of Sugar river at a 
sharp angle, whence it flows by a long bend on the north side of the hill. 
The channel of Sugar river is cut 150 feet deep in its original plain, over 
which its highest floods at the end of glacial time poured into the Con- 
necticut valley by two routes, one as now north of Trisback hill and Bar- 
ber’s mountain, the other south of these towards Ashley’s ferry. The 
highest portion of this plain in Claremont village is 565 feet above the 
sea, or 40 feet higher than the river above the upper dam. It thence 
slopes to 530 feet at one third of a mile east of the junction, and is shown 
on the east and north sides of the river to West Claremont, sloping to 
540 feet. The deposits of modified drift which are cut by the railroad at 
Ellis’s bridge, a mile south of Sugar river, and again just north of the 
junction, being respectively 515 and 500 feet above the sea, are remnants 
of these plains. They were both brought down at this time by the floods 
of Sugar river, the former on the north side, the latter on the south side 
of Trisback hill. The space between these deposits is a swamp, from 30 
to 40 feet lower, showing that the supply was not sufficient for filling the 
whole area west of this hill. 

The descent of Sugar river at Claremont village is 125 feet, of which 
about 100 feet is used for water-power. Below the foot of these falls it 
descends 100 feet more before it joins the Connecticut at 300 feet above 
the sea. 

In Charlestown and Springfield the normal high flood-plain of Con- 
necticut river was probably about 450 feet above the sea, or 150 above 
the river; but it is here more obscured by higher tributary deposits and 
the terracing process of erosion than in any other portion of the valley. 
It appears to be shown in the broad, uneven terrace west of Calavant 
hill; probably in that over which the railroad passes south from North 
Charlestown station; in the first terrace east and south from Beaver 
meadow, but not in that of the fair-ground and road northward, which 
is the delta of Beaver brook; in the terrace east of the cemetery at the 
village of Charlestown; and in the highest terrace, two miles long, above 
South Charlestown. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. SI 


An interesting dune was noted on the north-west slope of Calavant 
hill, near the north line of Charlestown. Its height is 598 feet above the 


Calavane hill 
3 5 6 3 6 avant hill, 
2 8 Ss % S g 598. 


300 ft. 


fr nm me ee om a mae eee eee Hee above sea. 


Fig. 13.—SECTION IN SPRINGFIELD AND CHARLESTOWN NEAR THEIR NORTH 
Lines. Length, 1} miles. 
sea, or about 150 feet above the original plain from which it.was blown 
by the north-west winds, as indicated by the sand-drifts, now principally 
covered by grass, that were left in its path. 

South from Little Sugar river a high terrace of till, on which the road 
is built, extends a mile and a half to the east side of Rattlesnake hill. It 
is nearly level-topped, and of about the same height in its whole length, 
being 550 feet, sloping to 540 feet above the sea. This terrace is com- 
posed of till, apparently unstratified and scarcely modified, except so far 
as its terraced form may be due to water. This is the upper till, distin- 
guished by its comparatively loose and sandy character. The underlying 
member is exposed by the gully of a brook near the school-house, being 
a blue, very compact, stony clay. 

In Springfield the whole or a part of the modified drift, lying between 
320 and 350 feet above the sea, presents an irregularly sloping contour 
for four miles, from the north line of the town nearly to Skitchawaug 
mountain. 

In Rockingham, opposite the south part of Charlestown, we find two 
considerable areas, which appear to be remnants of the river’s highest 
plain. One of these, more than a mile long by two thirds of a mile wide, 
is in the north part of the town, bordering the river. The second is as 
long, but only one fourth mile wide, extending to the south from near 
the mouth of Williams river. 

Deltas. Three prominent deltas occur in these towns, the products of 
Little Sugar, Black, and Williams rivers, with heights respectively 530, 
520, and 500 feet above the sea. The greatest extent of these deposits 
now remaining is in each case on the north side of the stream. Only 


52 SURFACE GEOLOGY. 


the upper portion of the delta of Little Sugar river is of the height men- 
tioned. Its principal mass is 50 feet lower, being the terrace cut by the 
railroad one third mile north of the river. It is almost wholly composed 
of gravel, in which the largest pebbles are one foot in diameter. In the 


Fig. 14.—FoLpED CLAvEY LAYER IN HORIZONTALLY STRATIFIED 
GRAVEL, NORTH CHARLESTOWN. Scale, 1 inch—ro feet. 


midst of this gravel a stratum 14 to 3 feet thick, consisting of clay ‘in 
layers a third of an inch thick, interstratified with a clayey sand, was 
exposed for 75 feet on the west side of this cut. Along half this distance 
it was levelly stratified, but beyond was irregularly crumpled, as shown 
in Fig. 14, apparently by lateral pressure. 

The wide, high delta of Black river has been cut through by Button 
brook, and has been variously terraced both by this brook and by Black 
river. A considerable portion of its plain between these streams is cov- 
ered by heavy white pine woods. ‘This delta increases the height of the 
upper terrace for more than two milés southward. The delta of Williams 
river is less extensive than the preceding, and at the same time has léss 
thickness, as it has been partly protected from erosion by ledges, which 
in some places form its border. 

Two miles north from Williams river the west bank of the Connecticut 
exhibits an interesting section (Fig. 15) of synclinal strata of clay and 
~«vxes  sand eroded to a level top, and over- 

52, laid by levelly stratified sand. The 
{ synclinal deposit appears to be the 
lower part of that which once filled 

Fig. 15.—SECTION OF RIVER-BANK, ie a * saat oe 

-RockincHam, Vr. Se Vea teh the valley. After its upper portion 

“too feet. ‘had been carried away, the overlying 

sand was brought in by a tributary, and subsequently terraced by the 

river. The most noticeable feature of the modified drift north and south 

from here is the wide interval or meadow, which extends from Charles- 

town village to Bellows Falls, and lies partly on éach side, being several 
times crossed by the river. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 53 


From South Charlestown to Cold river the precipitous face of Kilburn 
peak or Fall mountain forms the eastern boundary of the modified drift. 
Opposite Bellows Falls this leaves scarcely room for the railroad and the 
highway between it and the river. The height of this mountain is about 
1,200 feet above the sea. The water-shed on‘its north-east side in Lang- 
don, between the brook which flows into the Connecticut at South 
Charlestown and one of the branches of Cold river, is a swamp one sixth 
of a mile wide, 458 feet above the sea, or 175 feet above the river. Mod- 
ified drift, mainly coarse, extends south from this water-shed to Cold 
river. It was formérly supposed that the modified drift was deposited at 
a time when the valleys were made a series of lakes by the existence of 
barriers since swept away, and the narrowest space at Bellows Falls was 
regarded as the probable site of such an obstruction. No evidence point- 
ing to this was seen by us here or in any other portion of the valley, 
except so far as deltas, the ridge of the kame, or other unusually high 
deposits of modified drift may have acted in this way for a short time. 
It is obvious that with any high barrier here the river would have found 
passage over the low water-shed. north-east of the mountain. 

At Bellows Falls the river descends 49 feet (from 283 to 234 feet above 
the sea), through a narrow, water-worn channel of rock. Distinct glacial 
striz are seen upon these ledges at the head of the falls. The original 
highest plain seems to be shown by the upper terrace, 425 feet above the 
sea, which extends one mile north from the falls on the east side. This 
is about 30 feet higher than the remnant of the kame (p. 47), around 
which the high plain has been wholly:swept away and -the principal ter- 
race of the village formed, from 325 to 320 feet-above the sea. This 
area of fine alluvitim extends a third of a mile west from the falls, and 
it is almost certain that somewhere beneath it is a rocky channel lower 
than the head of the falls, in which the river flowed before the glacial 
period. In excavating the modified drift which was afterwards deposited, 
‘the river has formed its present channel close upon the east side of its 
valley, passing over ledges which are probably-much higher than its pre- 
‘glacial. bed. 

‘Cold and Saxton’s rivers have brought down large amounts of modified 
drift 75 feet above the normal high plain. The proper delta of the 
former has been eroded so far as it occupied the main valley, but the 


54 SURFACE GEOLOGY. 


escarpments thus formed remain at the mouth of the valley of Cold river, 
from 100 to 200 feet high. Thence a wide plain is found on the south 
side of Cold river for one mile, and again one half mile farther east at 
Drewsville. The west part of this deposit is sand or fine gravel, but in 
the east portion coarse gravel prevails. 

On the south side of Saxton’s river a considerable part of its delta 
remains, and the upper terrace is increased in height by this cause for 
two miles south. The excavation of this delta by Saxton’s river has 
formed a most interestingly terraced basin, situated less than a mile south 
from Bellows Falls junction. On both sides of this river, and crossed 
by a road, is an interval about one fourth of a mile in diameter. Around 
this on all sides are ranged terraces, which rise in succession like the 
seats of an amphitheatre, the highest on the north-west being 220, and on 
the south 200 feet above the arena below. They do not, however, show 
a perfect regularity either in correspondence of height or in continuous 
extent, and no single section would embrace all of the eight distinct and 
separate terraces which we noted on each side of the river. 

At Walpole village the limits between alluvium and till are not so dis- 
tinct as usual. The highest terrace of the Connecticut appears to be 
shown here 395 feet above the sea, and it is nearly continuous south- 
ward through this town, descending to 360 feet at its south line, where 
numerous dunes occur 30 to 50 feet higher. Irregular terraces intervene 
between this highest level and the river. 

In Westminster, opposite Walpole village and for one or two miles 
north and south, the modified drift is wide, and lies in beautiful, broad 
terraces. That of the village is 90 feet above the river, or 315 above the 
sea; another, 50 feet lower, extends one mile northward to the bridge. 

Through Westmoreland and Chesterfield the upper terrace varies be- 
tween 400 and 350 feet above the sea, the former height being reached by 
deltas three fourths of a mile south-west from Westmoreland depot and 
at and below the mouth of Catsbane brook. The modified drift in these 
towns is generally very narrow; but bends in the river give it a width of 
two thirds of a mile at two places in Westmoreland, one of which is a 
mile and a half south-west from the depot, and the other the same dis- 
tance north from the south line of the town. At both these points dunes 
occur on the hillsides just above the terraces. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 5 


In Putney, Dummerston, and Brattleborough, opposite the foregoing, 
we find nearly the same normal limit of the modified drift, and increased 
height of that brought in by tributaries. A bend of the river at the 
north-east corner of Putney gives to that town a notable expanse of 
low terrace, covering three fourths of a square mile. Many of the ter- 
races in Dummerston, especially for two miles north from the depot, 
slope more than is common towards the river, and are less distinctly 
separated by the usual steep escarpment. An interesting remnant of the 
kame occurs a third of a mile south-west from the depot (p. 48). At the 
west side of this ridge is a hollow of 100 feet, beyond which is an exten- 
sive deposit of kame-like gravel, which has been protected from erosion 
by a border of ledges on its south-east side. This has about the same 
height with the top of the kame, and appears to be of similar origin. 

Two large streams—West river and Whetstone brook—join the Con- 
necticut in Brattleborough. The latter flows through the centre of the 
village, supplying valuable water-power. A large part of its delta remains 
in the high plain at the south and south-west. The height of this a mile 
west of the river is 425 feet above the sea; at the Catholic cemetery, 
409; at the fair-ground, about 400. Above the west part of this plain, 
however, a still higher delta, at 490 feet, has been formed by a small trib- 
utary of this brook. This is the highest deposit of modified drift found 
in this valley south of Bellows Falls. The height of Connecticut river 
here is 200 feet above the sea. In the north-west part of Brattleborough 
village there rises a ledgy hill, about 525 feet above the sea, below which 
on the west is a belt of alluvium, extending north from the delta of Whet- 
stone brook to the valley of West river. Its northward slope shows it to 
be a part of the delta deposit of this brook. In the village erosion has 
removed the delta, giving on the north three principal terraces, 290, 308, 
and 341, and on the south two, 300 and 369, feet above the sea. 

West river is situated one mile farther north, and is larger than Whet- 
stone brook ; but it is of less interest, because it forms an exception to 
a general rule, having apparently brought no delta into the Connecticut 
valley. It has, however, labored so abundantly in hollowing out its chan- 
nel, that its course is through a beautiful basin, somewhat like that on 
Saxton’s river, mainly overflowed at high water and bordered by terraces, 
On the north side of its mouth are the most southern remnants of the 


56. SURFACE GEOLOGY. 


kame (p. 48); and on the south side an interesting series of secondary 
terraces, left as bench-marks of its progress in excavating the basin. 

The view of New Hampshire from Brattleborough is similar to that 
from Bellows Falls. At both these places, the largest towns in Vermont 
on this river, its eastern shore is an abrupt mountain wall, against which 
no terraces or only scanty remnants are found. Wantastiquit or West 
River mountain extends nearly four miles, with about equal portions in 
Chesterfield and Hinsdale, and rises to an altitude about 1,200 feet above 
the sea. The lowest point of water-shed at the east, near the head of 
Catsbane brook, is by estimate 650 feet above the sea, or about 200 feet 
above the highest portion of the Hinsdale plain. 

South-east and south from this mountain is the most extensive plain 
on this river in New Hampshire or Vermont, being three miles long, 
with a width decreasing from two miles to two thirds of a mile. The 
road from Hinsdale to Brattleborough passes over the south end of this 
plain, Here its height is 350 feet above the sea, or 165 above the Con- 
necticut at the mouth of Ashuelot river. It is mainly composed of sand, 
nearly level, but with a slight slope to the west and south, being as usual 
towards the river and in the direction of its course, Its extremity, three 


: SPOS aa) pe ' 
& tgfe2agt Fe ¢ ge Tite 
mn aMS FQUresy a a * oy 500 


Fig. 16.—SECTION IN VERNON AND Hee, Leer, 3 miles. 
fourths of a mile south-west from this road, is twenty feet lower. North- 
ward, its west edge is about 340 and its east side probably as high as 380 
feet above the sea, Its northern portion changes to gravel, which be- 
comes coarse on the south-east side of Wantastiquit, containing pebbles 
one foot or sometimes a foot and a half in diameter. The position and 
slope of this plain show that it was not deposited wholly from currents of 
the main valley ; evidently a considerable portion was contributed from 
the melting of the ice-sheet east of Wantastiquit mountain. 

Extensive sand-drifts or dunes blown from this plain occur on the hills 
at its east side for a mile and a half north from Hinsdale village. The 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 57 


highest of these at present drifted by the wind are about 100 feet above 
the east edge of the plain, but large amounts of sand now grassed over 
extend 50 feet higher. 

Ashuelot river at Hinsdale, and for a mile east, is bordered by terraces 
but little higher than the plain. Slight remains of an older delta, about 
400 feet above the sea, appear at its opening into the main valley, espe- 
cially above the railroad east of its mouth. This stream, like Whetstone 
brook at Brattleboro’, has formed numerous and interesting terraces in 
the alluvium of the Connecticut during the excavation of its channel to 
join that river. 

In Vernon, a high delta of small extent occurs on the north side of 
Broad brook. An isolated plateau, 70 feet above the low terrace sur- 
rounding it, and plainly a remnant of the principal terraces north and 
south of this brook, is found on its south side close to the river. It has 
been cut through for the railroad. Another plateau, similar to this, but 
only 15 feet in height, is cut through by the Ashuelot Railroad, just north 
of South Vernon. For two miles north from Vernon village the modified 
drift averages one mile wide, and is very finely terraced ; a half mile west 
from this village it consists of an extensive delta, 410 feet above the sea. 
One of the most picturesque portions of this river, as seen in our boat 
journey, was at this place in the circuit around Cooper’s point, where 
the river is divided by islands, and frequent gneissic ledges are exposed 
along its shore. These islands, and others along the river, are in nearly 
all cases alluvial and within the reach of high water. For a half mile 
east from Vernon the current of the river, by reason of this bend, has 
been so directed against its south shore that scarcely any alluvium re- 
mains, instead of which we have an irregular slope of till and ledge. 

Opposite Northfield village we find a prominent delta-plain of gravel, 
390 to 375 feet above the sea; and the first brook north of this village has 
brought down kame-like gravel and irregular delta deposits of similar 
height. The normal highest plain of the Connecticut seems to be repre- 
sented by the west portion of the Hinsdale plain; by the irregularly 
sloping terrace, which extends two miles north from Vernon, with its 
upper edge 340 feet above the sea; by an extensive terrace one mile east 
of Vernon, at 330; probably by terraces north and south of South Ver- 


non, at 295 and 290; by irregular remains in the south part of Hinsdale, 
VOL. 1 8 


58 SURFACE GEOLOGY. 


at 350, expanding into a plain in the south-west corner of Winchester, 
with a slope from 325 to 310; and by the plains at and south from North- 
field village, about 300 feet above the sea, or 120 feet above the river. 

An examination of the southern maps of Connecticut river (p. 40) 
shows a second apparently connected series of terraces, which probably 
marks one of the principal flood-plains formed by the river during its 
work of erosion. It exhibits a similar slope with that of the highest 
plain, or of the present river with its bordering intervals. This series is 
most clearly continuous below the north line of Brattleboro’, but seems to 
be traceable from White River falls, where it appears in the terrace on 
the west, from 435 to 455 feet above the sea, formed from the under- 
mined kame. It occurs north and south from West Lebanon, at 430 
and 440; one mile south of Mascomy river, at 440; opposite to this, at 
from 430 to 410; at North Hartland and opposite, from 412 to 400; 
probably at Hartland depot, from 425 to 410; in the north-west cor- 
ner of Cornish, from 380 to 375 ; at Windsor post-office, 354; in the ter- 
race of the railroad for four miles southward, from 360 to 350; in the 
principal terrace opposite Barber’s mountain, from 340 to 335; east of 
Weathersfield Bow, from 350 to 340; in the north part of Charlestown 
and Springfield, small terraces, 350; south from Black river, 360; on the 
road from Cheshire bridge to Charlestown, 350; in several places to South 
Charlestown, from 345 to 340; in the narrow curved terrace on which the 
road runs, one to two miles north of Williams river, from 335 to 330; in 
the principal terrace of Bellows Falls, and that of the Sullivan county 
railroad for one mile north, from 325 to 320; between Cold river and 
Walpole, 330; along the railroad, one to two miles south from Walpole, 
from 315 to 308; at Westminster village, 315; in scanty terraces, for five 
miles south, from 315 to 300; at East Putney and opposite, from 300 to 
280; for eight miles southward, numerous terraces, sometimes irregularly 
sloping, from 310 to 290; in Brattleboro’, from the north line to West 
river, a broad level terrace, 290; in the village, 290 and 300; at the mouth 
of Broad brook, the same; in the wide terrace of the railroad north from 
Vernon, 290; probably at Cooper’s point, 274; opposite Ashuelot river, 
275; at South Vernon, 270; on the west side of the river in Northfield, 
from 264 to 260; and on the east in a continuous terrace, varying from 
270 to 260, extending from one mile south of Hinsdale to the limit of 
our map and survey, two miles south of Northfield village. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 


59 


It will be seen that this list embraces the most conspicuous terraces 


below the highest plains. 


The formation of the terraces has taken place 


by excavation of a vast deposit that filled the valley level with these upper 
plains; and it might happen that at some period in the deepening of the 
channel the river would hold nearly the same height for a longer time 


than usual, after which the deepening might go on rapidly again, leaving 


the broad flood-plain then formed to be shown only by remnants, as in 


this series. 


At the least, it cannot be doubted that this is the true ex- 


planation of its most notable portions, as for the eighteen miles through 


Brattleboro’ and southward, and for eight miles south from Windsor. 


RECAPITULATION OF MopiFizD Drirt oF ConneEcTiIcuT RIVER. 


Distances in 
miles from Conn. 


HEIGHTS IN FEET ABOVE THE SEA. 


lake. 
9 ny Lo A 
PLACES. g 4 z 8 33 
8 > zs , Ss. 23 2 Altitudes for reference, and 
3a Pd S 25 ga Bs lane remarks. 
Ze | Be BE we DES 
A Oo Oo q a 
Labrador brook, . 5-4 5.6 5 Fourth lake, 255r. 
About] . Third lake, 2038. 
Deadwater stream, . 755 8 1300] 8 | 10, S. Second lake, 1882. 
2 Connecticut lake, 1618. 
Outlet of Back lake, . 8 8.5 o | 10,N. ; 30] Red school-house at the ‘‘Hol- 
ee Above river. low,” 6 miles from Connecti- 
Indian stream, . 10.8 Il.4 o | 15,N. 30] cut lake, r4g5. 
; z Hall’s Stream bridge, 1098. 
1 mile to south-west, 11.8 12.4 Ee 40,W. W. Stewartstown bridge, 1053. 
Q ee dam, 1049. 
Bishop’s brook, . . . 14.3 15.2 15 Colebrook bridge, 1025. 
Columbia bridge, rorz. 
Hall’s stream, . . . 15-2 16.3 108s} 1120, N 1120) North Stratford station, 915. 
, Beattie’s (flag) station, 880, 
West Stewartstown and 1049- Stratford Hollow, 877. 
Canaan, ay a 1765 18.7) 1035] 1x00, W.| Leach str., 1100] Groveton junction, gor. 
7 Hay scales, Northumberland 
2miles south,. ... 19.5 2 1025, 1080} Falls, 865. 
- Lancaster court-house, 867. 
4 ne Bs ies’, ako 21.65 24 1017] 1060} es station, 862. 
Beaver br. and] Sumner house, Dalton, 898. 
Colebrook,. . . 24.5 27-5 Io0ro 1ogo|~ Mohawk river,| Upper Waterford bridge, 689. 
nel) i100. a hay set, 
Columbia bridge, 28,3 31.7 992] z040, W.| Sims str., 1090) 752. 
: : Railroad near the mouth of 
Rapids 7 miles below 990- 50-60 P; ic river, opposi 
Beaver brook, . - | 30-37 |33-5-42 89x cs riv’r piigh wooded ind, 490. 
arnet station, 467. 
North Stratford and Stevens River dam, 557. 
Bloomfield,. . . 37, 41 891] 1010, E. Barnet church, 602. 
oe McIndoe’s station, 488. 
1¥% miles south, . 38.5 42.6) 880] 980 W. a os church, 510. 
onroe store and P. O. 5 
3 Ss Cee 40 44.2 875 eos ee Ryegate station, 471. sens 
e aay E zooo W.| Wells River station, 443. 
5 42 46.5) 868 ‘e 2 WT Railroad bridge, Connecticut 
939% river, 455. ‘ 
6 mg 5 8 865| § 94°» Jace h ae 
43 47 5 930, W Woodsville station, 455. 
Stratford Holl i School-house, x mileS. E., 526. 
tratford Hollow, 45 51.5 858] 935, E. North Haverhill church, 506, 
2 i station, 508, 
1¥% miles south, . 46.5 54.2 856 920 Haverhill town-house, ae 
Morse’ i 
Groveton, . . . 49 58.5 854) g00 south, aa aa 


Newbury Station, 426. 


SURFACE GEOLOGY, 


Distances in 
miles from Conn’ HEIGHTS IN FEET ABOVE THE SEA. 
lake. 
PLACES 2 Fs 3 bg 23 
- = Ea 5 
8m Ba. 3. Peas 2 Altitudes for reference, and 
s2 ra O48 83 ge. remarks, 
ie ge a> ag 8a4 
Bho EB BG cr was 
a oO is) qm ise) 
Northumberland Falls 852- te 3 Haverhill sta.,C. & P. R., qr2. 
il i 6 { Bye) FPn *e court-house, 664. 
and sCulldhall, Be ‘j 865, E. | Gaskill br., 940 Bradford station, 4r0. ; 
1% miles west, 52.5 63.5 840 { goo, W. i Piermont sation, {39-4 sé 
_E. » 596. 
3 miles north of Lancas- (865, E. Shaw’s mountain, about 750, 
Ler ere. AS 53°5 65-5 838 870, Ww vee station ie sek near 
a reat awyer’s mountain, 449. 
Lancaster, . 56.5] 70 835 865} Jsrael’s riv., 910 Baise: oa , 
re 5 é 
South Lancaster and «« street, 422. 
Lunenburg, . 60.7 76.2 832 860 Morey mountalas about goo. 
rout airlee pond, 415-419. 
Mouth of John’s river, 63.2 79. 830) 850| John’s riv., 870 ay station, 439. 
ort! etford station, 402. 
First half of Fifteen- | { 63.3- | {79.1- New a ‘ 2 East Thetford station, 413. 
miles falls, . . . . es 90.5 674 8 saa a st., 70 ne ene - 
al yyme churc' . 
Upper Waterford, 43 90-5 674] 4 | so-6o[% €N. &S., x00 see pond, 430. F 
Ss ater-she etween do. and 
Lower Waterford, 77-3 93-5 643 se aren nes Deas 545. 
.R, bridge, Pomp. river, 4o9. 
Fifteen-miles falls, be- | {77.3- (ae 643- 8 150- Norwich station, 406, oie 
low Lower Waterford, | 1 82.3 98.87 465 << 200 = ss pie 530. 7 
: anover, College church, ys2. 
_-— Passumpsic river, 83.5] 100 460 650] White River Junction, 369. 
bape 5 iv., 6 R.R. bridge, Quechee riv., 370. 
Barnet, . 85.4] 102 452 . 618 tevens riv., 675!;North Hartland station 388. 
Railroad summit, x miles 
Monroe and McIndoe’s ig { 440- 588, E north of Hartland, 464. 
- 7 
a eae 7-6) 4s} 430 | Se, WW. wie em 
1% miles south. . . 89.1] 106.5 427 ee W sed le c, 620. 
2 Plainfield village, 520. 
4 a eee 91.6} 109.2 420] ee ie Windsor station, 331. 
535, W- ts Ain Railroad bridge, Connecticut 
Woodsville and Wells ass a un on 8° river, 352. ; 
iver, a 95-4] 113.7 407 { ar ti 2°,9-! Vermont state prison, 389. 
530 | el's Tiver- | Ascutney Pond dam, Be. 
North _eerall and gl {505 E 600-660. Ealpous crossing, south edge 
ewbury, , 100 120.5 39) { eee —752, E,| _of Cornish, 368. 
, 478, W. SPE Tate “| West Claremont station, 404. 
Haverhill and So, New- Ez Oliverian br.,| High bridge (railroad) over the 
bury, . r awa 103-3 125.2 392 { a Ww { 630-750. 4 Sugar river, qos. 
“ 2 "| § Wait’s  river,| Railroad summit, 4% mile north 
Bradford, 107.5] 130.8 389 i? 9 6 | 583-600, of Clarerfiont junction, 478. 
es , . 460 #> East. _ brook,| Claremont, junction, 473. 
eT oh 9076s WL se Soldiers" monument’ fot of 
1¥% miles north from the acob’s br., shaft, 567. 
mouth of Jacob’s br., 111.8 137 384 440) is Be 575, peer dara, Sugar river, 525. 
i acob’s brook,| Foot of falls, 400 
Orford and Fairlee, . 113.8] 139 383 { 138 FE { 560-690. ieee hill, about aa 
aa : arber’s mountain, about 950, 
Ely station, 116.2] 147.8 381 Bees ee 530, W.! No. Charlestown station, 16. 
435, W- Lowest point of railroad, in 
North Thetford, . 118.4) 144.5 379 525 W. Beaver meadow, 314. 
Grant’s brook Springfield station, 374. 
Lyme and East Thet- { 525- 6 »| Skitchawaug mt., about gso. 
OFS: ee ses’ ash cae oe 120 3] 146.5 378 545 535-635. ee hill, about 650. 
ak hill, 625. i 
North line of Hanover Charlestown station, 375. 
and Norwich, . - 123.6] 150 376 535, So. Charlestown station, 302. 
: $45- Fall mountain, about 1200, 
Pompanoosuc river, . 125.2] 51.6 375 { 4: 2 59°] Water-shed N’ E. of do., 458, 
55?] ¢ Mink br., 586: Bellows Falls junction, 304. 
. 64. Blood inard’s pond, 592. 
Hanover and Norwich, 129.8] 156.5 373 { 500- 545 Bre 585; ne R. R, br., Saxton’s saint 278. 
: if 520, 7 overnor’s br., 257. 
West Lebanon & White ao2,27 Cold River station, 259. : 
River Junction, 133-8! 160.6 333) 510, W. acne Yr. 550. Walpole stan, 277. 
uechee river estmoreland station, 512. 
North Hartland, . 138.31 165.6 323 oo! 550-650. | Westminster station, 264. 


MODIFIED DRIFT ALONG CONNECTICUT RIVER. 


+ 


61 


Distances in 
miles from Conn. 


HEIGHTS IN FEET ABOVE THE SEA. 


lake. 
o ov rh on 
PLACES. £. | 4 4 58 23 
8S 2 3 scan » Altitudes for reference, and 
3s os 25 gs ge. remarl 
os ae BS ag ag4 
Ee Zi Ba we was 
a ro iS) q q 
{ Lull’s brook, eres crossing, 258. 
69. 630-620, etc.| East Putney station, 295. 
aie a “te “a ar era ‘Mill a 5 R. R. bridge, Sackett’s br. , 262. 
Windsor, 146.3] 174.1 304 500] spedee pee Pape en 
West Claremont and As- { 475, E. {Suger Ee 3, 8 ye Salmon a 3238. 
cutneyville, . 151.3] 179.1 300] (455, W. Dummerston cake 262, 
Sug.r. R. R. over road, 1% miles S., 
Claremont (on Rs Sugar 525, { Sugar r. 271. 
Fivet) ns 400 560-500} R.R. bridge, West river, 244. 
at b h station, 228. 
Weathersfield Bow, . 155 183.8 296 Bes a Brattle OrOUs: Catole esne 
450, W. i Sugar r., ysaod: 
North Charlestown, 158 187-5 293 459) 475-530. Wantastiquit mt., et 1200. 
{Bos "2 529° | School- house, % *mile west of 
Springfield station, 162 19.5, 289 450| | Beav’rbr. 1500.) > “Fyinsdale village, 373: 
South Vernon junction, 26x. 
Charlestown, e 163. 193. 28 0} é ri 
r Ww! 3 7 93°4 7 459) { Wiliams oe ah railroad bridge, eo 
South Charlestown, . 167.4] 197.5] 284] 450, E 500, Northfield Willages aoe" 
Bellows Falls, 2 170.5] 201 ee 425, E. Bernardston station, 353- 
we N fs 165.8. Slope of the highest normal 
1 mile south, 171.5] 202 230] 416, W. id river, terrace. 
soars a | Be 
Walpole, 174 204.8 226 395) 3 ae 
Westminster, 3 175.2| 206.2 225 ee a Hall’ en a | a 
Westmoreland ong nase Slab-hol’w br.,] © 3 miles north 
Putney, . 181 213 218| } 35° 345-375. ae a ae 6 | 10. 
| 360) sate! Ss br.,| << N. Stratford; 15% 3. 
Putney, . 184 216.2 215 350 365-385. ns pe 12 9 
Kamelike,w tance, | 74] 
420-440. i a8 
Dummerston,. . . 187 219.8) 210 350] | Catsbane br.,| ,, nae ms ei a 
Whtsene br.,| { Woodsville, ©] 8 | 8 
*| «2 miles north of 
409-425. Orford, 16%] 5 
Brattleborough, 192 225.2 200) 341] ) Trib. to do.‘on| ,, EI 
; S., 490. Ps ly station, a 4%4| 0 
7 N. Thetford, in 
North line of Vernon, . 193.5] 226.7] 197 340] Broad br., 425. | ee ae 
ae Plain Sele * Windsor, near- 
" Ashuelot 43} ly level, 28 I 
Hinsdale and Vernon, . 198 232.5 187 340) welot riv. 5} cz Weath. Bow, . 9 5 
ae #50 “* S.Charlest’ wn, 12 ° 
410. i Westmoreland, 14 7 
os. E, “* Hinsdale, wil) x I 
South Vernon, . . 201.8} 236.7 180 { aoe WwW “ Northfield, 6 6 
7 | £360, — 375- 
Northfield, 204 239 177| 305, E. { 390, W. Total distance, | 189 403 


Mopirizep Drirt atonc Lower Ammonoosuc River. 


Interesting deposits of modified drift are found on the Lower Ammo- 
noosuc river. Its course through the wide basin at the south-west foot 


of Mount Washington, descending more than 1 


,000 feet in six miles from 


the base of the mountain railway to the Fabyan house, is almost continu- 
ously bordered by large amounts of water-worn gravel, and sand becomes 


abundant in the last two miles below the Upper falls. 


These deposits 


62 SURFACE GEOLOGY. 


appear to have been formed at the disappearance of the ice-sheet, princi- 
pally consisting of material contained in its mass and set free at its melt- 
ing. Their origin was like that of the finer alluvium of the lowland 
valleys; and their date was at the end of the long period in which nearly 
all our deposits of this kind were formed. 

Modified drift of similar character occurs upon the South Branch. At 
the Crawford house, where several mountain torrents fall into the valley 
and form this stream, a great depth of very coarse stratified detritus has 
been brought down. This superficial deposit forms the water-shed be- 
tween the Connecticut and the Saco, carrying it a third of a mile north- 
west from the rocky summit of the pass, which is at the gate of the 
Notch. 

A well marked series of kames, or ridges of very coarse gravel, extends 
along the South Branch from about a mile north of the Crawford house 
nearly to its mouth. It appears again on the north-east side of the Am- 
monoosuc, between the mouth of this branch and the Fabyan house. 
Here it forms a single steep, narrow ridge, from 30 to 4o feet high, 
around which the river passes in a long southward bend. This ridge is 
conspicuously seen from the railroads on the opposite side. The mound 
known as the “Giant’s grave,” which was levelled down for the site of the 
Fabyan house, was a similar ridge about 300 feet long. This was noticed 
by Sir Charles Lyell, in his journey through the White mountains, who 
says it presented “the same appearance as those mounds which are 
termed ‘osar’ in Sweden.”* Other deposits of the same kind lie between 
this place and the White Mountain house, at the north edge of the allu- 
vial area. This series of kames appears to have been formed by a glacial 
river, which was fed from the melting ice-fields of the Mt. Washington 
and Mt. Willey ranges. Similar kames, which were also formed by 
glacial streams tributary to the Ammonoosuc valley, are seen along the 
Cherry Mountain road south from its summit. 

That the ice of this area, near the end of the glacial period, moved west- 
erly down this valley, is shown by abundant morainic boulders, which 
have been transported from Mt. Deception to the Twin Mountain house, 
where the glacier seems to have paused after its retreat from the lowlands 
and the valley below. The kames which we have described mark its 


* Lyell’s Second Visit to the United States. 


MODIFIED DRIFT ALONG LOWER AMMONOOSUC RIVER. 63 


diminishing extent at a later date. At both these dates great amounts 
of alluvium were brought down by its streams, forming a wide interval 
between the Fabyan house and the Lower falls, which fills what must at 
first have been a deep lake basin, and spreading out at and below the 
Twin Mountain house in an extensive low plain. The height of the 
former is from 1,560 to 1,550, and of the latter from 1,375 to 1,350 feet 
above the sea. Considerable deposits of modified drift occur at other 
points along the upper portion of this valley. 

Below Littleton we find the alluvium continuous, and usually in large 
amount on one or both sides of the river to its mouth. This is a distance 
of nearly twenty miles, in which the river descends about 400 feet, having 
its mouth 407 feet above the sea. The highest terraces near Littleton 
are from 60 to 75 feet above the river, but scarcely any deposits occur for 
the first five miles above the low terrace, which is partly interval. Below 
North Lisbon both this and the high terrace, which sometimes widens 
into plains, are well shown. South-west from North Lisbon the high 
terrace is about 100 feet above the river; at Lisbon, about 125; at the 
east line of Bath, 150; at Bath village, 175; and one mile from its mouth, 
200 feet, or 220 on its south side and 225 on its north side above Con- 
necticut river. The slope of the ancient high flood-plain of the Lower 
Ammonoosuc was thus about 12 feet to a mile, descending but little more 
than half as much as the present river. The only kame observed in this 
lower part of its valley was a short ridge of gravel between the railroad 
and highway at the east line of Bath. 


Mopiriep DrirT AND WATER-worN Rocks AT ORANGE AND NEWEuURY 
SumnIts. 


The lowest point in New Hampshire, upon the water-shed which 
divides the Connecticut and Merrimack basins, is at the summit of the 
Northern Railroad in Orange. Two rock-cuts, each about 30 feet in 
depth and together a quarter of a mile in length, were here made for the 
passage of the railroad through ledges of gneiss. Both these excavations 
were at the lowest points over which water could flow between these val- 
leys. At the south excavation the top of the ledge on the east side 
shows in a distance of about fifty feet three water-worn cavities, 4, 6, and 
12 feet deep, in order from north to south, one half of each of which has 


64 SURFACE GEOLOGY. 


been blasted away. Still more remarkable evidences of water action, in 
the form of cylindrical pot-holes, similar to those at Amoskeag and Bel- 
lows falls, formerly existed here, but were destroyed in the work of rock- 
excavation. The most interesting of these was called “the well;” it was 
situated on the north ledge, and was described by Jackson as 11 feet 
deep, 4+ feet in diameter at the top and 2 feet at the bottom. It was 
originally filled with earth and round stones.* The height of the railroad 
here is 990 feet above the sea, being about 30 feet below the natural sum- 
mits of ledge which were thus water-worn. The south ledge was three 
or four feet lower than the north ledge; and on both the water-worn 
portion was at their highest points, and thence extended down their 
south-east slopes. 

When we consider the great amount of erosion which was effected 
during the ice age, it seems impossible that these pot-holes and evident 
marks of extensive water-wearing could have been preserved through 
this period, especially when we take also into account that any barrier, 
which had before existed to turn a stream across this place, must have 
-been removed by this erosion. It becomes necessary, then, to inquire 
how such water-wearing could be produced during the melting of the ice- 
sheet. 

The modified drift found on both sides of this summit shows us the 
probable answer to this question. Our examination extended from Graf- 
ton Centre to East Canaan. The stream which we follow northward 
nearly to Orange summit is the head of Smith’s river. The first two 
miles to near Tewksbury pond show considerable areas of low, levelly 
stratified alluvium. From the north limit of this material we find no 
modified drift of any consequence for about two miles, extending over the 
summit, all the valley being ledge or glacial drift. No kame-like depos- 
its were seen in this distance. On the north side of the north rock-cut 
a deposit of water-worn gravel lies against the ledge. At one fourth 
mile farther north-west we find a kame from 500 to 600 feet long and 
about 35 feet high, the top of which has nearly the same height with 
the top of the rock-cuts. Similar short kames, sometimes 1,000 feet 
long, generally single, and nearly in line with each other, extend thence 
for a mile along the south-west side of the railroad. This material is 


* Jackson’s Final Report on Geology of New Hampshire, pp. 113 and 114. 


ORANGE AND NEWBURY SUMMITS. 65 


mainly coarse, water-worn gravel, with the largest pebbles usually about 
one foot in diameter, sometimes interstratified with considerable sand. 
Deposits which are also apparently of kame-like origin, consisting of 
gravel and sand, border the hills on the south-west side of the valley 
to East Canaan. This distance of nearly three miles has but little de- 
scent, and to the north and west the country is nearly level for consider- 
able widths in the valley, and not much lower than Orange summit. 
These areas are swampy, or are covered with low deposits of sand, which 
is also seen in patches on the hillsides from 30 to 4o feet higher. 
Large areas of low modified drift, often swampy, border the Mascomy 
river for several miles to the west. The heights of these points, in feet 
above the sea, are as follows: Grafton Centre, 871; Tewksbury pond, 
904; Orange summit, 990; top of railroad cuts, natural surface, 1,020; 
East Canaan, 956. 

The Merrimack valley, lying nearer than the Connecticut valley to the 
coast and outer limit of the great ice-sheet, and not being sheltered by a 
continuous belt of highland, was the first to become free from ice. It 
seems probable that the melting in the Merrimack basin proceeded north- 
westerly to this summit, which became the outlet from the melting ice- 
sheet over the nearly level area beyond. A long period appears to have 
followed before the ice disappeared from the Connecticut valley and along 
its bordering range of highland, of which Croydon and Moose mountains 
are the culminating points, so as at length to give the basin of Mascomy 
river a lower outlet to the west. The kames indicate the north-westerly 
retreat of the stream that descended from the glacial slopes; and the 
wide-spread, low alluvial deposits of Canaan mark the extent of the 
ancient lake, from which a large river nearly destitute of alluvium poured 
over the ledges of Orange summit into the Merrimack basin. 

Newbury summit, on the Concord & Claremont Railroad, was probably 
in a similar way the outlet from the basin of Sunapee lake during a part 
of the Champlain period. The ledge beside the highway, 150 feet east 
from the rock-cut at this summit, shows a pot-hole 24 feet in diameter, 
and the same in depth. With the present drainage no stream could exist 
to perform this work, which tells of a time when the ice-sheet had melted 
on the south-east and from the basin of Sunapee lake, while it still filled 


the valley of Sugar river, causing an outflow here to the east over the 
VOL. III. 9 


66 SURFACE GEOLOGY. 


present water-shed. Along the half mile between this summit and the 
lake, kame-like banks of gravel and sand are found; but in general the 
shores of the lake are destitute of modified drift, being composed of till 
or ledge. The heights of these points, in feet above the sea, are as fol- 
lows: Sunapee lake, low to high water, 1,090 to 1,103; Newbury summit, 
1,130; top of railroad cut, 1,181; pot-hole, about 1,175; lowest point over 
which water could flow towards the Merrimack river, 400 feet south-west 
from the rock-cut, 1,161. It seems probable that when this pot-hole was 
formed, the lower avenue at the south-west was still filled with ice. 

Another pot-hole, 10 inches in diameter and 3 feet deep, the origin of 
which we cannot explain, occurs about 20 rods north of Newbury station, 
at the shore of Sunapee lake, halfway between high and low water. There 
is no rivulet or depression leading to the lake at this point. 

In Warwick, Mass., two miles north-east from the village, the drainage 
during part of the Champlain period was also over the present line of 
water-shed, which separates Ashuelot and Miller’s rivers.* The current 
here was from north to south, as shown by an area 40 feet square of in- 
disputably water-worn ledges, with numerous pot-holes, which are locally 
known as “Indian kettles.” This place is near the lowest point of the 
water-shed, which is a swamp perhaps 25 feet below these water-worn 
rocks. While the ‘pot-holes were being formed here, the lowest place 
over which water could have flowed was probably occupied by an un- 
melted portion of the ice-sheet, as at Newbury summit. 


LitTLe SuNAPEE Lake, NEw Lonpon. 


The peculiar form of this lake, as shown on the county map, led to an 
examination of its surface geology. It is a mile and a half long from 
east to west, and is divided into nearly equal parts by a kame-like tongue 
of land, which extends fully a half mile from north to south, leaving at 
the south shore only a shallow channel about 50 feet wide. It is princi- 
pally surrounded by gently sloping hills of ledge or till, but a narrow 
margin of alluvium, 10 feet in height, borders its north-east shore. The 
materials of the dividing peninsula are sand or gravel, with boulders at its 
south end. Its width is less than 100 feet and its height about six feet, 

where it is joined to the north shore. The central portion is about a 


* Jackson’s Final Report on Geology of New Hampshire, p. 282. 


MODIFIED DRIFI ON ASHUELOT RIVER. : 67 


sixth of a mile wide and 30 feet high, gently sloping from the middle to 
the shores. This is used as a picnic ground, and is covered by pitch and 
white pines and white birches, the characteristic trees of our sandy plains. 
The southern portion is most like our ordinary kames, being mainly nar- 
row, and in some places scarcely a rod wide. This peculiar accumulation 
of modified drift appears to be due to a depression formed here in the ice 
at its melting, into which these materials were carried by the glacial 
streams, Afterwards a hollow was left on each side at the disappearance 
of the ice. 


AsnuEeLot River IN KEENE AND SWANZEY. 


The principal valley of Cheshire county has its widest development in 
Keene and Swanzey, as shown on Plate V. When the ice melted here, 
this basin contained for a short time a body of water somewhat larger and 
probably deeper than Sunapee lake, which soon became filled by the allu- 
vium of floods which the retreating ice-sheet sent down by every tributary 
from north, east, and south. The city of Keene is built on the east, por- 
tion of these level deposits, which are here two and a half miles wide, 
and extend with nearly the same width two miles to the north and the 
same distance to the south. The Ashuelot river flows through this basin, 
lying near its east side above Keene, but crosses to its west side in the 
north part of Swanzey. Its west portion in Keene is drained by the last 
four miles of Ash Swamp brook. Three miles south from Keene the 
Ashuelot river finds an avenue westward, along which it is also bordered 
by low modified drift for several miles. The straight valley, however, 
continues to the south through Swanzey, being occupied by the South 
branch and Great brook, with an alluvial area which decreases from one 
mile to one third of a mile in width. We thus find here a valley ten 
miles long from north to south, filled with nearly level deposits which are 
but slightly higher than the streams, and bordered by steep and nearly 
continuous ranges of hills, which rise from 400 to 600 feet upon each 
side. This alluvium consists almost everywhere of sand or fine gravel, 
perhaps extensively underlaid by clay, which is worked for brick-making 
near the south edge of the city of Keene. Its height is from 10 to 4o 
feet above the river; and the whole plain was originally of the same 
height with the highest portions, which still occupy the greater part of 


68 SURFACE GEOLOGY. 


the alluvial area. These are generally separated from the lower interval 
by steep escarpments, which show that the difference in height is due to 
excavation by the river. 

The only kames found in this area were several small irregular ridges 
of coarse gravel at Woodland cemetery in Keene. The railroad cut north 
of the bridge at South Keene shows successive layers of coarse gravel 
and sand. These are 40 feet above the highest plains, being the delta 
deposits of the branch which here enters the valley. South from this 
station for one third of a mile we have irregular ridges 4o feet high at a 
short distance west of the railroad, resembling kames in form, but scarcely 
differing from common till. In the south part of Swanzey we find occa- 
sional terraces, which are sometimes of coarse gravel, from 60 to 70 feet 
above Great brook, showing that much material at first deposited here 
was afterwards channelled out by this stream and carried northward to 
the wide low plains. 


MopiFi—ep DriFT ALONG THE PEMIGEWASSET AND MERRIMACK RIVER. 


The river which drains the central portion of New Hampshire has a 
quite direct course slightly east of south. Its only departure in this 
state from the general direction is between the villages of New Hampton 
and Bristol, where it makes an offset of four miles to the west. This val- 
ley affords one of the few avenues for crossing the mountainous region. 
It begins in the deep gap of Franconia notch, between abrupt mountain 
walls, and it is at first closely enclosed by the high ranges which extend 
thence to the south. For twenty-five miles, or nearly to Plymouth, the 
valley is singularly straight, as is well seen from the summits of Lafay- 
ette and.Cannon mountains, which rise at either side of its source; or it 
forms a beautiful view from hills in Campton, with its fertile intervals and 
well tilled farms extending for several miles, beyond which, at the end of 
its long vista, are the serrated mountains cleft by the notch (vol. i, p. 551). 
Its entire length from Profile lake, Franconia, to Massachusetts line, is 
comparatively straight, forming a continuous line of depression, which is 
a principal feature in the topography of the state. The upper and lower 
portions of the river which occupies this valley are known by different 
names. For more than fifty miles from its source this river is called 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 69 


Pemigewasset, and the name Merrimack is applied to it only from the 
confluence of the Winnipiseogee at Franklin. * 

The modified drift of this valley in New Hampshire is illustrated by 
Plates IV and V; these maps, like those of the Connecticut valley, show 
the extent of the intervals, terraces, and plains on both sides of the river, 
with their heights above the sea, The Pemigewasset river has a develop- 
ment of alluvium usually one half to one mile wide, which is bordered by 
high hills or mountains, forming a deep valley similar to that of Connecti- 
cut river along our western boundary. The modified drift of the Merri- 
mack is usually one to two miles wide; its greatest development is in 
Concord, and in Litchfield and Merrimack, where it has a width of nearly 
four miles. The hills which border this part of the valley rise with com- 
paratively gentle slopes, and the lowest points of its eastern water-shed 
are only 350 to 650 feet above the sea, unlike the continuous belt of high- 
land which lies between this river and the Connecticut. After entering 
Massachusetts the Merrimack river turns east and north-east; and, with 
scanty deposits of modified drift, threads its way to the sea through a 
maze of hills which are composed of coarse glacial drift or till. Here the 
river has no connection with the principal questions in surface geology, 
which are quite different from those presented for study along its course 
in New Hampshire. 

On the Pemigewasset river we find modified drift first at J. Guernsey’s, 
in Lincoln, five miles from Profile lake. Thence for two and a half miles 
southward this consists of coarse gravel, much water-worn, extending one 
sixth to one third of a mile in width on the west side of the river. The 
mountains extend quite to the river along this distance on its east side. 
This modified drift has an irregularly smoothed surface, sometimes im- 
perfectly terraced, with its outer margin at the north from 15 to 20, and 
at the south about 40 feet above the river. Its pebbles are from six 
inches to a foot and a half in diameter, and sometimes larger. Boulders 
also occur here and there, from three or four to ten feet in size. 

A large plain of similar gravel occurs east of Pemigewasset river, on 
the north side of East Branch, having a height of from 30 to 40 feet 
above the river. Material for this plain was brought both from the north 


* The boundaries, area, and topographic features of the Merrimack basin are described in Vol. I 


PP. 205, 212, 
300, 306, etc. : (eae. 


79 SURFACE GEOLOGY. 


and east. Nearer to the river here we have a lower terrace only from 5 
to 10 feet above it. In the excavation of the gravel deposits, the river 
has sometimes left numerous and well marked terraces, though small in 
extent, and differing but little in height. This is well shown near Tut- 
tle’s, in Lincoln, where four distinct terraces are seen between the road 
and the river, with from 3 to 5 feet escarpments, the highest being about 
20 feet above the river. 

The height of terraces in this valley was determined by levelling only 
as far north as to the mouths of East Branch and Moosilauke brook, 
which enter the Pemigewasset, from opposite sides, at nearly the same 
point. The river here is 710 feet above the sea, or only 242 feet higher 
than at Plymouth, eighteen miles farther south. Profile lake, its source, 
nine miles to the north, is about 1,950 feet above the sea, by barometric 
measurement, showing a descent to this point of more than 1,200 feet.* 

The plains above the East Branch, not determined by the level, appear 
to be somewhat lower than the highest modified drift just south of this 
stream. This terrace has a height of 70 feet above the sea, and is ten 
feet higher on the west side. Thence for ten miles southward, or nearly 
to the south line of Thornton, the highest terrace of the river, commonly 
well shown on both sides, has a uniform continuous slope of 15 feet to 
the mile. This is nearly the same as the descent of the river, which 
has cut its way from 70 to 100 feet deep through its former wide, sloping 
flood-plain. These remnants, lying at corresponding heights on opposite 
sides of the river, and sloping with it in the regular lines of the upper 
terrace, are here very interesting, as seen extending for miles up and 
down the valley. Nowhere else in New Hampshire is the erosion of 
a the modified drift, by which it 
ed has been shaped in terraces, so 


710, 
765. 


w ° 
wn fad 
nw nw 


Pes r. clearly and convincingly display- 


o9€%---© above sea. 
Fig. 17.—SECTION IN WOODSTOCK, 14 MILES 
BELOW THE MOUTH oF East Brancu. that an original flood-plain, ten 
Length, 3 mile. 


ed. Here no doubt can remain 


miles long, has been terraced as 
we see it by the excavation of the river. For most of the way along 


*The errors which occur in Vol. I, pp. 288, 308, and 322, in stating the height of Pemigewasset river at the 
mouth of East Branch, and of other points in this vicinity, arose by computing barometic observations from 
Thornton, which, through some mistake, is given 600 feet too high by Prof. Guyot, among the usually very cor- 
rect altitudes published in his memoir on the ‘‘Appalachian Mountain System.’ 


Plate IV. 


PP & 


the Modified Drift of 


(>, PEMIGEWASSET An MERRIMACK 
i, RIVER. 


SCALE or MILES. 


This horder is the true meridian for all the mape enclosed. 


Dunes =700-825. 


HELIOTYPE 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 71 


this distance, which lies through Woodstock and Thornton, we have 
two principal terraces, the higher being that just described, and the 
lower being wholly or in part overflowed by spring floods; but small 
intervening terraces are also of frequent occurrence. 

All the modified drift of this valley, for the first seven miles to Wood- 
stock village, is made up of gravel of different degrees of coarseness. 
Southward, banks and terraces of sand begin to appear; but gravel still 
predominates for a long distance below. The stream here frequently 
occupies a broad, shallow channel, paved with pebbles of all sizes to two 
feet in diameter, with little admixture of fine gravel or sand, which can 
accumulate only in deep or sheltered places. 

Kames. In the south part of Thornton an interesting kame of coarse 
gravel is found on the west side of the river, between it and the highway. 
It extends north and south in a steep, sharp ridge about a fourth of a 
mile, and is less distinctly traceable for nearly a mile. Its top is go feet 
above the river, or 650 above the sea. Less than a mile farther south 
the road turns to the west around the steep face of a high plateau of 
kame-like gravel, which contains abundant pebbles up to a foot and a 
half in diameter. This deposit is of considerable extent, with its south- 
east portion nearly level, 660 feet above the sea, or about 100 above the 
river, but towards the north-west it has a broken surface, which in some 
places is 10 feet higher. It is from 30 to 40 feet higher than the normal 
upper terrace, which extends, with its regular slope of 15 feet in a mile, 
to this point, beyond which it also continues clearly traceable to the 
south. This higher plateau and the kame, which it resembles in mate- 
rial, date before the formation of the continuous high flood-plain. We 
must refer the latter to a time when the valley had become free from ice, 
while the former seem to belong to the period of its melting, owing their 
shape, in isolated plain and steep ridge, to the presence of ice-walls be- 
tween which they were deposited. 

In Campton the Pemigewasset receives two considerable tributaries 
from the east—Mad and Beebe rivers,—which drain basins on the north- 
west and south-east of the mountain range that culminates in Sandwich 
Dome. South from the latter stream the upper terrace, increased in 
height by alluvium from the tributary, forms a pine-covered plain a mile 
long and half a mile wide. These “pine plains,” appearing in a few 


72 SURFACE GEOLOGY. 


places on the Pemigewasset and commonly along the Merrimack, we find 
to be one of the characteristic features of this valley. The modified drift 
of Campton occurs principally in the upper terrace, which has a normal 
height of 620 to 575 feet above the sea, or about 70 feet above the river, 
and in the interval or present flood-plain. At Livermore falls, near the 
south line of this township, the river passes through a deep, rocky gorge, 
with a natural fall of 22 feet. The foot of the falls is 483 feet above the 
sea. 

In Plymouth and Holderness both the upper terrace and interval are 
finely shown; and the extent of the alluvial area, at one point a mile and 
a half wide, is greater than at any other place on Pemigewasset river. A 
beautiful interval extends for three miles below the mouth of Baker’s 
river; at the north, mainly on the east, and at the south, on the west side. 
The broad, high plain belongs to Holderness, being on the east side. 

Baker’s River. A wide area of modified drift also lies along Baker’s 
river below Rumney. For most of the way it is widest on the north side, 
reaching back at the widest place to Loon pond, a mile from the river. 
This likewise occurs in two heights, terrace-plain and interval, the former 
40 to 50 feet above the river. The railroad extends over this alluvium 
nearly six miles in a single straight line. 

The upper terrace, in Holderness, Ashland, and in the north part of 
Bridgewater, is 570 to 560 feet above the sea, or 100 above the river. 
Thence in six miles to New Hampton village it descends to 510 feet, or 
72 above the river. It is best shown along this whole distance on the 
east side. There is almost always one lower terrace, and sometime sev- 
eral; but we find only small areas that are overflowed south from the 
large interval of Plymouth. Deltas higher than the normal upper terrace 
occur at two places near the north line of Bristol, and at the villages of 
Ashland and New Hampton. Spectacle pond, in the edge of Meredith, 
probably has its outlet by a subterranean channel, which extends un- 
der gravel and sand a mile to the west, appearing near the east edge of 
New Hampton village in several springs. The largest of these supplies 
a stream of very cold water two or three feet wide and a foot deep. 
Gravel ridges or kames bordering the Pemigewasset were seen in Ash- 
land half a mile above the mouth of Squam river, and in Bridgewater at 
Eastman’s falls, four miles farther south. No other deposits of this kind 
were observed between the townships of Thornton and Franklin. 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 73 


Dunes in Merrimack Valley. 


In the north part of New Hampton, and in many places for thirty miles 
southward to the north line of Concord, we find numerous dunes or sand- 
drifts lying at various heights on the east side of the valley, up to 300 
feet above the highest terraces.. Near their beginning, two miles south 
of Ashland, these dunes appear in large amount, and reach their greatest 
height. Here the sand-drifts, one to five feet deep, are strewn in a path- 
way 10 to 20 rods wide, which extends a fourth of a mile along the hill- 
side, with. a north-west to south-east course, rising 300 feet above the 
ordinary modified drift, or to a height of about 825 feet above the sea. 
These dunes of the Merrimack valley, like those along Connecticut river, 
occur only on the east side, consist wholly of fine sand, and lie in trains 
which ascend from the highest terrace in a south-east direction along 
the hillside. All these characteristics indicate their origin, through trans- 
portation by the prevailing north-westerly winds from the plains below, 
probably at the period when these had their greatest extent, prior to their 
excavation by the river, and, we may presume, before the appearance of 
a forest. They are usually made conspicuous at the present time, by 
being blown in drifts which are so constantly changing that they give 
no foothold to vegetation; but when they occur at considerable heights, 
we generally find the lower portion of the series grassed over, making 
the upper drifts appear isolated on the hillside. This is the case at the 
locality described in New Hampton. The upper part of this series, ex- 
tending an eighth of a mile, is still in motion, and has been gullied and 
channelled by the wind often 3 to 6 feet deep over spaces 50 to 100 feet 


Dunes, 
825. 


fo) 
a) 
+ 
m% 


450 ft. 


* above 
Fig. 18.—SECTION IN BRIDGEWATER AND NEw Hampton. sea, 


Length, 1} miles. 


= 7 ome ene weenwen ae ows} 


long, and carried forward, probably some portions 300 feet ahead and 50 


feet higher, within fifty years. The whole train of sand-drifts at this 
VOL, III 10 


74 SURFACE GEOLOGY. 


place is equal, by estimate, to a mass 1,000 feet long, 50 wide, and 2 feet 
deep, thus containing 100,000 cubic feet, or 5,000 tons, which have been 
raised by the wind an average height of 150 feet. 

Another very good illustration of this transporting: power of the wind 
is found in Sanbornton, a mile south-east from Hill, on a hillside which 
reaches a height 400 feet above the river, or 700 above the sea. Here 
the ancient dunes, as in New Hampton, have been swept forward anew 
since the land was cleared. The sand from a hollow 150 feet long, 40 
wide, and 2 to 5 feet deep has been carried in long north-west to south- 
east drifts 200 to 400 feet farther, and 25 to 30 feet higher up the hill. 
The depth of recent excavation is shown by a large stump which has 
been thus undermined. The highest of these dunes have now reached 
the crest of the hill, covering the originally naked ledges; but they 
will not stop here, and at length may be found far beyond in the hollow 
on the east side of this first hill range. 

Through Franklin and Northfield these dunes are numerous, occurring 
from 100 to 300 feet above the upper terrace of the valley, having their 
greatest altitude, 700 feet above the sea, a mile and a half north of North- 
field depot. They are generally found, however, within 100 feet of the 
highest terrace: at such height they are well shown within a mile north 
and south from Franklin Falls, near Northfield depot, and in great abun- 
dance, extending more than a mile on the north and west sides of Hart 
hill, In the next five miles no dunes were observed, but they appear 
again at a similar elevation for a mile in the south part of Canterbury. 

The instances of dunes found southward along the Merrimack are soon 
enumerated. They have a height of 70 feet, by estimate, above the high- 
est terrace in Pembroke, on the west side of the village street, where they 
are covered with grass; they reach about the same height in London- 
derry, two miles south-east from Goff’s Falls, where they appear in large 
amount, forming irregular mounds and ridges; and at a few points in 
Litchfield and Hudson we find on the high plain, and scarcely raised 
above it, similar areas of barren, wind-blown sand. 


From New Hampton to Bristol the river flows westerly, almost at right 
angles with its general direction, descending by a nearly continuous slope 
86 feet in the four miles, which are the most rapid portion of its course 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 75 


south of the East Branch. The same rapids continue a mile or two be- 
low Bristol, so that the total descent in six miles from New Hampton 
bridge to the mouth of Smith’s river is 118 feet, or from 438 to 320 feet 
above the sea. The westerly course of the Pemigewasset here corre- 
sponds to that of Connecticut river along Fifteen-miles falls. These are 
the only considerable deviations of these rivers from their general direc- 
tion in the state; both portions are of rapid descent over till; they are 
alike bordered by sloping hills; and both differ from all the rest of these 
valleys in being well-nigh destitute of modified drift. Remnants of the 
original high flood-plain, now forming the normal upper terrace, traceable 
on both sides nearly all the way from the East Branch to Massachusetts 
line, appear to occur in the highest of two terraces at the mouth of Ten- 
mile brook; in a small, gently sloping plain about midway between New 
Hampton and Bristol; and in a similar area east of the highway a short 
distance north of Bristol. All these are on the north side of the river, 
and are from 510 to 500 feet above the sea. At several places along 
these rapids it appears probable that the channel has been cut through a 
considerable depth of till. 

Bristol village is built almost wholly on till or ledge. Below Main 
Street bridge the fall in Newfound river is 105 feet, and its total fall from 
Newfound lake is 238 feet, the lake being 590 feet above the sea. The 
usual display of terraces again commences opposite Bristol, and thence 
the alluvial area extends, with the river, unbroken through the state. 

At the mouth of Smith’s river the highest terrace, 460 feet above the 
sea, is wide for a mile to the north, and extends in a narrow strip for the 
same distance to the south. Thence southward to Franklin we find re- 
mains of the same, principally on the east side, from 480 to 440 feet above 
the sea. In the south part of Sanbornton they form an extensive plain, 
475 feet above the sea, probably slightly increased in height by the tribu- 
tary alluvium of Salmon brook, which has cut a channel along its south- 
east side. From this plain a wide terrace (from 475 to 440 feet) extends 
south on the east side to Franklin, where the normal upper terrace is 
again shown on both sides of the valley, forming on the west the high 
sandy plain, 445 feet above the sea, which extends a mile north-west to 
Webster lake. 

Lower terraces are numerous on both sides for a mile below Smith’s 


76 SURFACE GEOLOGY. 


river, the lowest being interval. West of Hill village an expanse three 
fourths of a mile long and a half mile wide is divided, by escarpments 15 
and 20 feet in height, into three distinct terraces, the highest of which is 
410 feet above the sea. A small terrace, 80 feet higher, is found on its 
west side. The highest terraces west of the river, well shown much of 
the way between Hill and Franklin, are from 40 to 60 feet below those 
on the east. This difference seems to be due to a deficiency in the 
amount of material supplied, the deposition being influenced by the cur- 
rent, and attaining its full height only on one side. 

Kames. A short gravel ridge, projecting five feet above the plain of 
which it forms the border, and containing pebbles six inches in diameter, 
was seen in the north part of Franklin, on the west side of the road at 
one mile south from Hill village. Another gravel ridge, about 20 rods 
long and 35 feet above the plain on the west edge of which it occurs, was 
seen in Sanbornton near the river, a mile and a quarter south-east from 
the last. Both these short ridges are of typical kame gravel; they lie 
nearly in the middle of the valley, and their heights are about the same, 
the northern being 385 and the southern 365 feet above the sea. It is 
not improbable that these are remnants of a formerly continuous kame. 

This coarse gravel was next observed at a railroad cut on Bristol 
Branch, one mile above Franklin depot; an excavation of it may be seen 
in Franklin village, just north of Webster brook, at the west side of the 
street; and it is again exposed in the same way a short distance south of 
the depot. It also forms a ridge, nearly covered by the fine alluvium of 
the upper terrace, on the east side of the river, one fourth of a mile above 
the bridge. Southward in this town kames were noted at two places on 
the west side. 

At Boscawen village portions of a well marked kame form the escarp- 
ment of the plain, which has about the same height, near the north end 
of the street and south from the road to the bridge. One mile farther 
south we find between the highway and the railroad a ridge several hun- 
dred feet long, the north part of which is composed of coarse water-worn 
gravel, while its southern portion seems to be unmodified till. 

The ancient highest flood-plain of the Merrimack from Franklin to 
Massachusetts line is everywhere well shown by the conspicuous upper 
terraces. Along much of the way these expand on one or both sides into 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 77 


wide, sandy “pine plains,” so called because their principal wood-growth 
consists of white or pitch pines. These are sometimes accompanied by a 
thick and tangled undergrowth of scrub oaks, which, with the pitch pine, 
flourish best on the barren plains. Their surface is very level, with a 
regular but very slight slope, which amounts to nearly the same as the 
descent of the river. In some places this may be finely seen, as at Con- 
cord, where a level set at the same height with the plain on the east side 
commands a view of its edge for three miles along the river, in which dis- 
tance it is seen to slope only a few feet, with no undulation to break its 
straight line. 

It is worthy of notice, that in this entire valley, including Pemigewas- 
set river, no important deltas are found. This is in remarkable contrast 
with the Connecticut valley, where the regular line of the river’s highest 
alluvium is hardly traceable, or is less readily seen much of the way, be- 
cause of the extensive higher deposits of tributary streams. In this valley 
such deposits have helped to fill extensive areas, as in Concord, for which 
it would seem that otherwise the supply must have been deficient, and 
sometimes they slightly increase the height of the upper terrace, but in 
no place do they form, as on the Connecticut, frequent and well marked 
terraces above this normal line. The Merrimack valley is wider than 
that of the Connecticut, giving room for its ample plains; and its sides 
slope more gently, forming lower ranges of hills. Its tributaries partake 
of the same character, and also have a less rapid descent than in the Con- 
necticut basin, allowing the deposition of large amounts of alluvium along 
their course, as on Baker’s, Contoocook, and Suncook rivers. The modi- 
fied drift of the Merrimack is rendered more simple, but not less instruc- 
tive, by being free from the confusion of associated tributary deposits. 

At Franklin the upper terrace is well shown upon both sides of the 
valley. It has considerable fall in a short distance here, being 445 and 
440 feet above the sea at the north side of Webster brook and Winnipi- 
seogee river, and descending in less than a mile to 430 and 420 feet at 
their south sides. The mouth of Winnipiseogee river is 269 feet above 
the sea, the Pemigewasset having descended nearly 30 feet in its last 
mile, so that the upper terrace here has a height 150 to 175 feet above 
the river. The highest alluvium for eight miles northward, extending 
through Sanbornton and including the large plain north of Salmon brook, 


78 SURFACE GEOLOGY. 


has an equal elevation above the river, which is greater than in any other 
portion of this valley. In the next nine miles below Franklin the upper 
terrace falls to a height of 125 feet above the river, which continues for 
more than 20 miles to the north part of Manchester, the highest terrace 
seeming to descend most rapidly near the present falls of the river, so 
that a nearly uniform height above the river is maintained. 

Opposite the Webster place, two and a half miles below Franklin, this 
high terrace presents a quite remarkable form. Its base is washed by 
the river, which here sweeps eastward, leaving a fertile low terrace of 
large extent on its west side. Ascending from the river to the east we 
have first the steep escarpment, more than 150 feet high, the top of which 
has nearly the normal height of the upper terrace; but this, without any 
level space as usual, is succeeded by a sloping surface of sand, which ex- 
tends to the road, and rises about 120 feet in less than a fourth of a mile, 
appearing in all except its slope like an ordinary terrace. Very high 
sand-dunes occur on the hill south-east, and it seems probable that this 
unusual slope, rising more than 100 feet above the normal height of this 
terrace, was heaped above it by the north-west wind, soon after the time 
of its deposition. A similar sloping surface of the upper terrace, but 
much less in amount, is also seen for a mile or more north and south, 
and at many other points along the river. Between one and two miles 
farther south we find the greatest profusion of dunes observed in New 
Hampshire, the highest of which, however, do not exceed 250 feet above 
the river. 

In Canterbury the upper terrace spreads out into plains, which are at 
some places a mile wide. The Boston, Concord & Montreal Railroad 
through the town is upon these high plains, while the Northern Railroad, 
in Boscawen and Concord, lies on the lowest terrace, being embanked 
much of the way to raise it above the high floods of spring. The plains of 
the south part of Canterbury, extending one mile into Concord, show an 
unusually rapid continuous slope, amounting to 80 feet in four miles, or 
from 130 to only 50 feet above the river, which is here 250 feet above 
the sea. The north end of this slope appears to be at the normal height, 
representing the level of the river at the time of deposition of these 
plains, while the terrace of Boscawen village, on the opposite side of the 
river, is 40 feet lower. The south end of this slope is about 70 feet 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 79 


below this normal line, which is here shown on the west side in the plains 
north and south of Fisherville. 

Boscawen village is built on the south end of a similarly sloping terrace 
three miles long, in which distance it falls 30 feet, and we find 30 feet 
more fall of the same terrace in less than a mile along the village street. 
The whole of this terrace is below the normal height, showing a defi- 
ciency of 15 feet at its beginning, and of 40 feet at the north end of Bos- 
cawen village. It appears as if the supply of alluvium was insufficient, 
and the direction of the current at first caused it = 
to be deposited in greatest amount at one side, 
without filling the valley. South of Boscawen the 


«‘Whale’s Back’’ 
Kame, 350. 


350. 


supply of material became still more inadequate, City of Concord. 


290. 


and the lower portion of the sloping plains east 
of the river was probably 60 feet below the surface 
of water, which was held back by the extensive 
plains of Concord, derived in large part from the 
Contoocook and Soucook valleys. 


R. R. 252. 


240. 


R. 227. 


240. 


weeer rede resee 


me Ae 


Although the plains in Concord were obviously 


¥ 


brought in from tributary sources, they belong to 
the ancient flood-plains of the Merrimack, since 


*GYOONOD NI NOILOTS—"61 “31 


they form a portion of the series of high terraces 
and plains which extends with a slightly varying 
but unbroken slope along this whole valley. Even 
if no modified drift were supplied, except from the 
upper part of the main valley, irregularities of 
slope, as in Boscawen and Canterbury, with in- 
creased height below, as in Concord, would still 
be produced by an irregular rate of retreat of the 
ice-sheet, allowing long and abundant deposition 
in some portions, but much less in other portions 
of the same valley. In this way we must explain 
the sudden and permanent increase in height of 
the upper terrace of Connecticut river at North Thetford (p. 36). Prob- 
ably this cause was combined with the aid of tributaries to produce the 
high plains in Concord and southward. 


Between Fisherville and West Concord these plains have a large 


an pers enenenane 


‘OSE ,,‘sureyd eC, 


*soqttu ¥€ ‘yysuaT 


“SOULS 


a Soucook river, 


“vas DAO(EMera awa weenvesss 


80 SURFACE GEOLOGY. 


extent, lying on the south side of Contoocook river. Their northern and 
western portions are 125 feet above the Merrimack river at the head of 
Sewall’s falls, but they become slightly lower at the south. The mouth 
of Contoocook river is 249 feet above the sea. Its descent through Fish- 
erville, in the last mile and a half of its course, exceeds 100 feet. By the 
Borough dam, at the head of these falls, this river is held level to Con- 
toocookville in Hopkinton, six miles in a direct line. Along this distance 
and beyond we find extensive alluvial areas at small elevation above the 
river, continuous with these plains in the Merrimack valley. A descrip- 
tion of the modified drift of Contoocook river will be hereafter presented. 

The most extensive plains in Concord, and indeed in this entire valley, 
lie on the east side of the Merrimack between it and the Soucook river. 
They extend along Merrimack river six miles, from above East Concord 
to the mouth of the Soucook. Their area of greatest width, which ex- 
ceeds two miles, is opposite the city, being known as the “Dark plains.” 
The channel which has been excavated by Soucook river is very crooked, 
lying at first along their east edge, but at three miles from its mouth 
deviating towards the middle of the plains, and again returning eastward 
and southward. This excavation is 50 to 125 feet in depth, with areas of 
low terrace at its bottom bordering the river. The greater part of this 
large expanse of plain is very level, with occasional gullies, but with 
scarcely any undulations rising above the general surface. Its slope, in 
nearly four miles from its north-west limit to opposite the south part of 
the city, is only 10 feet, with a height 130 to 120 feet above the river, or 
the same above the river as the plains north and south of Fisherville, 
their difference in absolute height being equal to the descent of the river 
at Sewall’s falls. Farther south the slope of the plain becomes more 
rapid, descending 50 to 75 feet in about two miles, the highest portions 
at the south end being about 100 feet above the mouth of Soucook river, 
which is 199 feet above the sea. The total descent of the Merrimack in 
Concord is thus 50 feet, of which 20 feet are at Sewall’s falls, four 
miles above the city, 5 feet at rapids a short distance above the mouth 
of Turkey river, and 20 feet at Garvin’s falls, three fourths of a mile 
below. 

In Boscawen and Canterbury, and through Concord, the lowest terrace 
for 12 miles occupies a wide area, of which a large part is overflowed by 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 81 


the high water of spring, forming the only extensive intervals on this 
river south of Plymouth. These are from a half mile to one mile wide, 
their fertility being in marked contrast with the barrenness of the 
“pine plains.” A fine view may be obtained in Canterbury and Concord 
from the edge of these plains, whose high bluffs descend abruptly a hun- 
dred feet, overlooking the level bottom-lands and the windings of the 
river for miles north and south. In other parts of its course the river is 
confined between terraces, which prevent an irregular route. Its mean- 
dering course here was signified by the aboriginal name Penacook, or 
crooked place, which was applied to the south part of this territory. 

Ancient river-beds are indicated at many places by shallow ponds, 
which lie in long and frequently curved depressions of the interval, often 
near the foot of the higher terraces, and but slightly elevated above the 
river. One of these is seen on the east side of the railroad, a mile south 
of Boscawen depot ; one lies on each side of the river just south of Sugar 
Ball bluff, near Concord; and others occur east of the south part of the 
city; but the largest and most interesting is Horseshoe pond, at the 
north end of the city, which is shaped like a crescent, being a half mile 
long, nearly as wide as the present channel, and six feet above the ordi- 
nary height of the river. This pond is crossed by the Northern Railroad. 
Its middle portion lies at the foot of a higher terrace, against which 
the river once swept its full current. The nearest point of the present 
channel is a half mile distant at the north, where the river bends and 
now directs its current against Sugar Ball bluff, a mile and a half north- 
east from Horseshoe pond. The date of these changes cannot be stated, 
except that it was before the first settlement here, 150 years ago. 


Recent Changes of Merrimack River in Concord. 


Dr. William Prescott, of Concord, in 1853 collected dates and measure- 
ments of many remarkable changes in the channel of Merrimack river 
which had taken place since a careful survey of this portion was first 
made in 1804.* From this record it appears that below Federal bridge, 


* Collections of N. H. Historical Society, vol. vii. At the time of publication of this volume, in 1863, a state- 
ment was added describing subsequent changes to that date. : 


In the same volume is also found a valuable address on “ The Valley of Merrimack,” by Joseph B, Walker, 
Esq., describing its physical features, and recounting its earlier and later history. ; 


VOL. UI. IT 


82 SURFACE GEOLOGY. 


near East Concord, the river has changed its entire width from south- 
west to north-east, and a third of a mile to the east it has changed more 
than its width in an opposite direction. On the east side of the “Fan” 
or broad interval opposite the north part of the city, the river flowed in 
1804 by a very circuitous route 460 rods, which was shortened to 150 
rods by great freshets in 1826, 1828, and 1831, which cut a direct course 
across two peninsulas then known as Sugar Ball point and Hale’s point. 
Ponds already mentioned occupy portions of the old channel. Ten years 
later, Dr. Prescott reported the rapid undermining of Sugar Ball bluff, 125 
feet high, of which the river had carried away, between 1853 and 1863, a 
mass 80 rods long and 40 rods wide. . This erosion is still going forward, 
being aided by springs near the foot of the bluff. At Davis’s bluff, about 
a mile south, a width of three rods was swept off in 1863 in three days. 
Erosion at this point has continued thirty years, requiring a dwelling near 
the edge of the bluff to be several times moved, and the road changed. 
The same undermining of the high plains by the river is also going on 
at several places north and south of Fisherville. One mile south-east 
from Boscawen bridge, the plain, 110 feet above the river, is fast wear- 
ing away, and portions of it 10 feet wide and 150 feet long had fallen 
in 1875 10, 20, and 40 feet, remaining nearly level, so that their sapling 
pines, 10 to 30 feet high, were still upright and growing on the side of 
the steep sand-bluff. These would be carried away, to be followed by 
new slides during the next high flood. One mile farther south, and at 
other points below Fisherville, a similar rapid erosion was observed. A 
quarter of a mile north-east from Fisherville bridge, a bluff, which has 
been so recently undermined that it is not yet grassed, is now separated 
from the river by a wide area which does not exceed five feet above the 
ordinary height of water. These recent incursions of the river upon the 
plains, and the rapid changes in its channel upon the intervals, washing 
away yearly from one bank and adding to the side opposite, leave no 
doubt that the river has flowed at the foot of the bluffs along their whole 
extent, occasionally making a deep excavation beyond its ordinary bounds, 
as on the east side south of Sugar Ball bluff; that the high plain once 
filled the whole valley; and that the river has swept many times from 
side to side over the space occupied by its lower terraces and interval. 
Important changes in the channel of the Merrimack have also been 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 83 


made artificially in Concord. One mile south of Fisherville depot the 
course of the river was formerly in a westerly curve, passing around 
Goodwin’s point, two thirds of a mile from its direct course. At the 
west end of this detour it was fast undermining a long line of bluff 125 
feet in height. When the Northern Railroad was built, in 1846, the river 
was turned, to avoid bridging, into a new channel, by which its course 
was made straight, being shortened fully a mile. Its old channel remains 
filled with water, except at its south-west bend, which is nearly silted 
across; and the erosion of the bluff at times of freshet is greatly dimin- 
ished. Farther south, at about three miles above the city, the river 
flowed in two channels, of which the west one was largest, enclosing 
Sewall’s island. The railroad was built across this island, reaching and 
leaving it by embankments instead of bridges, for which purpose the 
west channel was dammed, when the river is said by Dr. Prescott to 
have swept away, to widen its east channel, a width of 20 to 25 rods of 
its bordering interval for two thirds of a mile. 

Dr. Prescott mentions that, in cutting the new channel across the base 
of Goodwin’s point, “the workmen, at the depth of about 12 feet, struck 
upon a bed or stratum of vegetable matter, consisting of leaves, branches, 
and trunks of small trees, the latter from three to six inches in diameter, 
the form of which was perfect, and the bark distinct. This vegetable 
deposit was found embedded in a stratum of fine blue sand, which at first 
sight was mistaken for blue clay, and was from one to three inches in 
thickness. The trunks and large branches were recognized as belonging 
to the natural order coniferz.” He also describes, from an excavation 
at the gas-works in Concord, supposed “fragments of the roots, trunks, 
and branches of trees. They were found deposited in a stratum of fer- 
ruginous sand (composed of sand and oxide of iron); and in some in- 
stances the fragments of roots and branches of trees were completely 
incased in a firm coating or crust of the oxide of iron and sand from one 
eighth to one half an inch in thickness.” This was at a depth of ten feet. 
It appears probable that these were cylindrical concretions of oxide of 
iron, which often show concentric rings, almost exactly imitating the 
annual layers of wood. These were found abundantly in the excavation 
for laying the water-works main, in 1872, near the south line of the city 
farm, and may be occasionally met with in any alluvial sand. 


84. SURFACE GEOLOGY. 


Between West Concord and the city the upper terrace is from 10 to 30 
feet lower than on the east side of the river. The greater part of the 
city, and a large area southward to Turkey river, are slightly lower, being 
about 300 feet above the sea, or 75 above the river. In the west part of 
the city the modified drift, composed of sand or fine gravel, rises unter- 
raced into irregularly sloping hills, the highest of which, crossed by 
Church and School streets, are 367 feet above the sea, being higher than 
the plains of the east side. 


Kames in Merrimack Valley. 


Interesting kames are found at Concord, where they form the uneven 
east part of Blossom Hill cemetery, and extend south in a nearly continu- 
ous series, composed of irregular, short, low ridges and mounds, always 
with north to south trend, to the intersection of Franklin and High 
streets, and thence on the same course to Centre street. The south por- 
tion of this series is a single steep ridge, from 25 to 40 feet high, called 
“Whale’s Back,” which originally extended a quarter of a mile from near 
the corner of Centre and Pine streets to that of Warren and Liberty 
streets. The north half of this has been used by the city in making and 
repairing streets; for which this gravel, when screened to remove its 
coarse pebbles, forms an excellent surface, and ultimately the whole ridge 
will thus be removed. The material of “Whale’s Back” is mainly very 
coarse gravel, containing abundant pebbles up to one foot, while the larg- 
est reach two or three feet in diameter. These are always well rounded, 
having the characteristic water-worn form,—not that of glaciated boulders, 
which are distinguished by flattened, striated sides, with rounded corners 
and edges. This water-worn gravel lies in a steep, narrow ridge, a sec- 
tion of which usually shows an indistinct anticlinal bedding. The round- 
ed boulders, pebbles, and fine gravel are almost indiscriminately mingled 
through the whole mass, often with very scanty streaks of sand or other 
lines of stratification. 

This series of kames lies at the west margin of the wide alluvial area, 
resting upon till 100 to 125 feet above the river. Its extent is a mile and 
a half, having the same course with the valley. No kame-like deposits 
were discovered along the east side of the river in Concord, the whole 
mass of the plains being fine alluvium. Similar ridges were next found 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 85 


just below the mouth of Soucook river, exposed by railroad excavation on 
both sides of the Merrimack. The kame here cut through by this river 
is a portion of a series which extends twenty miles from Loudon to Man- 
chester. . 

In materials, arrangement, and stratification this principal line of kames 
in central New Hampshire is like the short series just described, but un- 
like the long single kame of the Connecticut valley. The greater part of 
these kames is of very coarse, water-worn gravel, with pebbles six inches 
to two feet in diameter, disposed in irregular ridges from 40 to 100 feet 
in height, of southerly trend parallel with the valley, a section of which 
usually shows an indistinct stratification. This, however, varies occasion- 
ally to coarse angular materials, mainly consisting of unworn rock-frag- 
ments up to four or five feet in size, with no evidence of water action. 
A mile south of the Pinnacle in Hooksett a gradual transition is seen 
from water-worn gravel to this morainic material, which continues about 
a sixth of a mile and then changes back to modified drift, the whole form- 
ing a continuous ridge. Other portions of these kames contain consider- 
able amounts of sand or fine gravel, alternating in irregular layers with 
the common coarse gravel, thus showing very well marked stratification, 
which is always inclined, being usually anticlinal or arched in the section 
of a ridge. 

This Merrimack series differs notably from that of the Connecticut in 
being frequently composed of several ridges, nearly parallel to each other, 
with long irregular hollows between them which sometimes contain ponds. 
About half is thus made up of two or more parallel ridges, while the other 
half, in separate portions of a mile or two each, consists of a single ridge. 
Upon the Soucook river these kames are repeatedly cut through by its 
present channel, as also near its mouth by the Merrimack, but in the 
fourteen miles farther south they lie wholly on the west side of the 
Merrimack, often near the edge of its alluvial area. 

The north end of this series has not been fully examined. Its first 
appearance noted is on Pine brook, half a mile west of Loudon village, 
where north-west to south-east ridges of coarse gravel occur. They were 
also seen on the south-west side of Soucook river, near the first bridge 
below this village; thence they probably occur near the river southward, 
but have not been explored for the next mile and a half, to near Richard- 


86 SURFACE GEOLOGY. 


son’s mill in Concord. Fora fourth of a mile north from this mill, and five 
and a half miles southward along the Soucook to its mouth, these ridges 
have been carefully traced, and are found well developed, rising 40 to 100 
feet above the river, and nearly continuous, sometimes single, and again 
two or three parallel and of equal height. These kames, for the first three 
miles, lie close to the river, almost wholly on its west side. The material 
is prevailingly very coarse, but for the most part plainly water-worn, with 
the largest pebbles or rounded boulders two or three feet in diameter, 
and it occurs in steep, narrow ridges 40 to 75 feet high. The river above 
Richardson’s mill is 307 feet above the sea; hence these kames do not 
exceed 400, and those west of Loudon are probably about 450 feet above 
the sea. 

At Clough’s mill, three miles above its mouth, the Soucook departs 
from its general course, crossing the line of kames, and turning with a 
right angle one mile to the west. Below this point the river does not 
follow, as before, the eastern border of the plain; but we find that the 
kames continue in a nearly straight course close to this east boundary. 
For a mile and a half from Clough’s mill the kame lies on the east side 
of the road. In the first half mile of this distance we find a single steep, 
narrow ridge of coarse, water-worn gravel, 20 to 40 feet above the adjoin- 
ing plain. Sections of this ridgé are exposed by the river at Clough’s 
mill, and by a cut across it for a new road at a short distance south. In 
the next mile we find the same coarse gravel, lying partly in the form of 
a ridge, but not so prominently, and partly in a somewhat irregular ter- 
race, 

One mile above the mouth of the Soucook, where it comes near the 
highway, a distinct gravel ridge occurs on its east side; and on its oppo- 
site side we have two parallel ridges, separated by a hollow, but with the 
top of the west one the same in height with the adjoining plain. The 
largest pebbles seen in this ridge were one foot in diameter. Thence 
for nearly a half mile no kames are found; but after passing the lowest 
bridge on this river they are well shown on its east side to the railroad 
near its mouth, forming a broad ridge of gravel, with pebbles up to a 
foot and a half in diameter. The direction of this ridge points to the 
continuation of the series on the opposite side of Merrimack river. 

A fine section of the kame has been exposed by excavation for the rail- 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 87 


road at the point where it reappears in Bow, one fourth of a mile north of 
Robinson’s station. Here the water-worn gravel, containing none but 
rounded pebbles, the largest of which are two or three feet in diameter, 
forms a well defined, anticlinally stratified ridge about 4o feet high, which 
is entirely overlaid by the later sand deposit of the ordinary terrace. 


Fig. 20.—SECTION OF KAME OVERLAID BY SAND, 4 MILE NORTH OF 
Rospinson’s STATION. Scale, 1 inch=60 feet. 


Thence the series extends for a mile in a single ridge, which is partially 
and at some points wholly covered by the fine alluvium. In the next 
mile we have two ridges nearly parallel, but somewhat irregular in course 
and in height. The intervening hollow contains a small pond. These 
ridges form the east border of wide plains, which have nearly the same 
height with the kames. The sand of the plains is shown to be the most 
recent deposit by its superposition. It appears that, after the gravel 
ridges had been formed, great amounts of sand were swept into the val- 
leys; but spaces nearly enclosed between parallel ridges were often pro- 
tected from this deposition. In the subsequent excavation of a large 
portion of this sand by the river, producing the lower terraces and its 
present channel, these coarse ridges have been a barrier protecting the 
plains on their west side. Opposite the mouth of Suncook river, the 
eastern of the two ridges lies on the south-east side of a small brook;— 
here we again found for a few hundred feet numerous angular rock-frag- 
ments, of dimensions from one to two and a half feet, while other por- 
tions, so far as seen, were of water-worn but often very coarse gravel. A 
short distance farther south the series is suddenly interrupted, and its 
direct course is occupied by a high, ledgy hill, An irregular high terrace 
of gravel and sand on its east and south-east sides may represent the 
kame. After a mile the series reappears in its characteristic ridges, and 
continues five miles quite irregularly and of varying material, but plainly 
one connected series to its next gap, which begins opposite Martin’s 
Ferry. 


88 SURFACE GEOLOGY. 


In Hooksett the kames are well shown for a mile north from Pinnacle 
pond. Several small ponds lie in the irregular hollows at the sides of 
these ridges. A well marked kame forms the east border of the high 
terrace west of Hooksett village and north-east from the Pinnacle, di- 
rectly east of which it could not be traced, but it reappears in a ridge 
on the south side of the road south-east of this quartz peak, thence turn- 
ing south-west towards the principal range of these kames, the direction 
of which seems to lie from north to south across Pinnacle pond. The 
locality of greatest irregularity in respect to shortness of ridges, inequality 
in height, variable course, and diverse material, found in this whole series, 
is the first half mile south from this pond. The scale of the map, how- 
ever, does not permit details to be shown. <A deep, winding hollow 
extends along the west side of the main ridge from within one fourth of 
a mile of the pond to a junction with the valley of a small brook nearly 
a mile south. A considerable portion of this hollow seems to be due to 
excavation; and for the next mile southward, where a single nearly 
straight ridge parallel with this brook constitutes all that we have of the 
series, the plain, which is 30 to 40 feet above the top of the ridge, has 
been so washed away that a wide hollow has been formed at both sides. 

Here the plain is sand or ordinary gravel, but the kame is mainly com- 
posed of the very coarse, water-worn gravel, which forms the principal 
portion of this series. This, however, is here found changing into coarse 
unmodified material, in which angular boulders, mostly of gneiss or gran- 
ite, two to five feet in their dimensions, occur almost as closely packed 
together as possible, with the gravel of the interspaces unmodified by the 
wearing of water. This forms a well defined narrow ridge, 25 to 40 feet 
high, which continues a sixth of a mile, or perhaps more, when it changes 
again to materials rounded and sorted by water, and wears the usual 
aspect of these kames. 

Next below this long single ridge the brook finds a passage to the 
river; and a very remarkable assemblage of kames, partly water-worn 
and partly angular, succeeds, covering an area half a mile long and one 
fourth of a mile wide, with short parallel or irregular ridges, most of 
which trend from north to south. These ridges are nearly level-topped, 
with intervening hollows at the north 30 to 40 feet deep. Near the mid- 
dle of the area a deep hollow runs transversely across the course of the 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 89 


kames from west to east. South from this the space between the ridges 
has been mainly filled with alluvium, forming a plain upon which the 
position of the kames is easily traced by their lines of coarse gravel. 
Occasional boulders, apparently brought by floating ice, lie on the sur- 
face of this plain. One of white quartz, six feet long, has thus travelled 
more than two miles from its parent ledge, which was probably the Pin- 
nacle. 

The course of the kames now turns eastward and then westward at 
the end of a mile, conforming to a bend in the valley. At the north this 
curve consists of a single low ridge, which is in large part composed of 
angular rocks up to one or two feet in size, lying between the road and 
the river. Where it turns to the south-west, opposite Martin’s Ferry, we 
have a broad gravel hill, in which also many of the stones are angular, 
while other portions are water-worn. Thence for two miles southward 
the kames have been wholly carried away by the river, which has its 
channel directly in the line of their course. 

On the east side of the river this series may be represented in the high 
plain one mile north of Martin’s Ferry, which has irregular ridges and 
hollows, and is composed of gravel with pebbles six inches to one foot 
in diameter; but a large area of similar gravel, extending thence to the 
north-east, seems to be clearly a tributary deposit. An undoubted rem- 
nant of the series occurs half a mile south from this station, in a coarse 
gravel deposit, showing oblique and irregular stratification, which has 
been excavated for railroad ballast. Occasional angular boulders, three 
to six feet in size, which must have been brought by floating ice, were 
noticed in the same terrace. 

In Manchester a fine display of these kames begins at the west side 
of the river road, a mile and a half above Amoskeag bridge, and their 
greatest development in the whole series is thence south-west to Piscata- 
quog river, where they cover an area two miles long by one fourth to 
half a mile wide, closely adhering to the west side of the widened valley. 
We find here as many ridges as can well occupy this space, all lying in 
the same course, which is that of the series, and having a comparatively 
uniform height. Some of them probably extend almost the entire length 
of this area, while others are short or broken by gaps. Their material is 


principally water-worn gravel, sometimes as fine as prevails in the Con- 
VOL. III, 12 


gO SURFACE GEOLOGY. 


necticut kame, and interstratified with sand, but more commonly very 
coarse, as is characteristic of this series. Other portions are unmodified, 
containing angular stones; and large boulders are occasionally found, 
Three long hollows, varying from 30 to 50 feet in depth, one being wholly 
enclosed, lie between these kames for a half mile at their north end, be- 
yond which the hollows have been filled with fine alluvium, producing 
a nearly level plain. Southward, many irregular long hollows are found, 
one of which contains a pond. An ancient channel, occupied by the 
whole or a part of the Merrimack when it first began to excavate its 
highest plain, extends along the south-east side of this area of kames. 
Rock Rimmon lies a quarter of a mile farther south-east, and the exten- 
sive plain around it is destitute of kames. 

This series makes almost a right angle where it is crossed by the Pis- 
cataquog river, nearly two miles above its mouth, and turns south-east 
for a mile, consisting of a single ridge of water-worn gravel, which lies 
near and parallel to the river. It is well exposed at this angle by excava- 
tion for the Manchester & North Weare Railroad a short distance west 
of its bridge. An exploration of the Piscataquog valley for two miles 
farther west showed high and low terraces of fine alluvium, but no kame- 
like deposits. The south-east course of the kame with this river would 
have led to the conclusion that its origin was from this tributary valley, 
had not the whole series been traced and found at other places as here 
closely following the west side of the Merrimack valley. 

Near Piscataquog village the course of the series turns to the south, 
crossing the New Boston road about an eighth of a mile east of the cem- 
etery. This road passes through a gap in the principal ridge, which both 
on the north and south is filled almost as compactly as possible with 
angular fragments of rock one or two feet in size. Through this gapa 
portion of the river formerly flowed, and its ancient channel extends a 
mile to the south, lying on the west side of the kame. South-east from 
this gap, and east of the coarse ridge of angular materials, we find a small 
plateau, which belongs to this series, and is composed of well-rounded 
gravel, the largest pebbles having a diameter of two feet. A thin cover- 
ing of sand forms the surface here, but excavations show the coarse 
gravel, which is prepared by screening for the manufacture of concrete 
pavement. This series terminates within a half mile to the south. After 


MODIFIED DRIFT ALONG MERRIMACK RIVER. g! 


being traced continuously six miles along Soucook river and fourteen 
miles along the west side of the Merrimack, it stops here, and similar de- 
posits were next found fourteen miles below in Hudson and Nashua. 

These kames at their beginning reach a height about 100 feet above 
the Soucook river, or 400 to 450 feet above the sea, and they continue 
at nearly the same height above the river to its mouth, where they are 
300 feet above the sea. Along the Merrimack they are 325 to 265 feet 
above the sea, or 100 to 125 above the river. The only point where a 
ridge is found much lower than this is at the eastern curve of the series, 
in the south part of Hooksett, where it is only about 50 feet above the 
river. The large area of kames in Manchester rises 100 feet above the 
head of Amoskeag falls; and the ridge and plateau south-west of Piscata- 
quog are 15 feet lower, being 142 feet above the foot of these falls, and 
265 feet above the sea. With an irregularity in height which is almost 
constantly changing within limits of twenty-five feet, we thus find these 
kames, as a series, preserving a comparatively uniform elevation above 
the present river, which is about the same as that reached by its ancient 
flood-plain. 

The origin of these remarkable ridges must be explained in a similar 
manner with that of the long single kame of Connecticut river. The 
date of their formation was at the melting of the great ice-sheet. The 
comparatively fine gravel and frequent layers of sand in the Connecticut 
kame attest a slow. melting of the ice, long water-wearing of its material, 
and deposition from a moderate or even gentle current. The Merrimack 
kames, as far north as to Loudon and Concord, indicate a much more 
rapid departure of the ice, which allowed less time for the formation of 
rounded gravel, and was attended by strong currents. A section of the 
Connecticut kame shows, by its alternation of coarse and fine materials, 
that successive summers and winters were occupied in its accumulation. 
The same appearance is often seen in the Merrimack series, but fre- 
quently a section of these kames is without very definite stratification ; 
and all its materials, which are then very coarse but commonly much 
water-worn, appear to have been deposited by a nearly uniform and very 
powerful current, like that of a single summer. 

The deep ice-channels in which the kames were accumulated seem to 
have been formed only at or near the mouths of the glacial rivers, not 


Q2 SURFACE GEOLOGY. 


extending far from the melting edge of the ice-sheet. In this lower por- 
tion of the Merrimack valley, and elsewhere in eastern New Hampshire 
and Massachusetts, the retreat of the glacier seems to have been so rapid 
that extensions of these kames were often entirely deposited in a single 
year. The ice-walls by which they were enclosed melted back about as 
fast as the formation of the channels and kames advanced. Though 
separate portions of these kames were thus probably wholly deposited 
in a single year, their annual progress was small; and the formation of 
the entire series, extending 20 miles, occupied a long period. 

The substitution of coarse angular materials, instead of the common 
water-worn gravel, seems to have taken place at times of very rapid melt- 
ing, whenever such materials happened to be set free from the ice in large 
amount near the mouth of the glacial rivers. They were then swept by 
the violent current into the place of the ordinarily water-worn kames. 
At the most notable of these localities, which occurs in Hooksett (p. 88), 
a medial moraine, or a similar train of materials which had become en- 
closed within the ice, seems to have been thus undermined by the glacial 
river, and left to appear as a portion of this series. 

It remains to add a few statements in regard to kames found farther 
southward in this valley. A fourth of a mile west from Reed’s Ferry 
we noted irregular ridges of partly angular and partly water-worn mate- 
rials, which enclose small ponds in their hollows. These kames appear 
to be isolated, not forming a portion of any series. After discontinuance 
for fourteen miles next below the long series which extends from Loudon 
to Manchester, we again find lines of kames in the main valley, upon both 
sides of the river and a mile apart, in Hudson and Nashua. They begin 
in Hudson, a short distance south-west of Otternic pond, and extend 
southward two miles. This series may be seen at the north side of the 
road leading east from Nashua bridge, near where the river road. turns 
off to the south. It is traceable from this point a half mile north- 
ward, consisting of two or more crooked ridges 20 to 30 feet in height. 
This material is considerably water-worn, the largest pebbles seen being 
a foot and a half in diameter. Following the river road southward, we 
find but.a single ridge, similar in height and material, but nearly straight, 
which lies for the first third of a mile on the east side of the road, and 
beyond on the west side, diverging from it towards the river. This ridge 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 93 


is 75 to 100 feet above the river, which is here 93 feet above the sea. 
The modified drift of the next half mile southward, extending to an ex- 
posure of the till, consists of a level gravel plain, 75 feet above the river, 
which contains pebbles up to one foot in diameter. This very coarse 
alluvium has a greater height than the finer deposits west of the river. 
It seems to be of earlier date than these plains, or even than the kames 
northward, and was probably formed in the same way with the latter, dif- 
fering only in its greater extent. 

In Nashua, excavations have been made in remnants of the kames on 
the north side of Canal street, and on the west side of the Nashua & 
Lowell Railroad, a quarter of a mile south from the Concord depot. A 
short series seems to extend from the latter point to the south-west, 
principally concealed by later deposits. A mile and a half farther south, 
near the city farm, we find another ridge which has been excavated for 
gravel at its north end. This extends south-easterly nearly continuous 
for a mile, and is from 20 to 40 feet high. The road lies parallel with it 
on its north-east side for four fifths of this distance, but at length turns 
to the south, crossing the kame and rising above the alluvial area, of 
which this ridge forms the border. The material of these ridges is 
water-worn but quite coarse, containing stones up to one and a half or 
two feet in diameter. These kames are probably to be regarded as por- 
tions of a series which was never connected. A mile southward it ap- 
pears again, here also at the west margin of the alluvium, between the 
highway and railroad, south of Little’s station. The highest of these 
kames in Nashua does not exceed 100 feet above the river. This series 
does not appear to extend into Massachusetts. 

Several other deposits of this kind were noticed at the west and north- 
west within the limits of our map. Fairmount heights, a coarse gravel 
plain on the north side of Nashua river, west of the city, is a deposit of 
similar origin with the kames. Near the west line of Nashua, ridges and 
mounds of this gravel occur on the south-east side of this river. Other 
kames, forming very coarse gravel ridges, were observed in the north 
part of Hollis near a school-house and saw-mill, on the south side of Pen- 
nichuck brook; and in Amherst, a third of a mile south from the railroad 
station. Similar deposits, most frequently of small extent, may be found 
in almost every town in New Hampshire. 


94 SURFACE GEOLOGY. 


The description of the ordinary alluvial terraces and plains of the Mer- 
rimack was interrupted at the mouth of Soucook river. Thence nearly to 
Manchester the average width of the alluvial area is about one mile. Its 
narrowest place is at Hooksett, where ledgy hills rise close to the river 
on both sides. The Pinnacle, a sharp peak of white quartz on the west, 
350 feet above the river, affords a very beautiful view of the valley north 
and south, including several villages. The most interesting portion of the 
alluvium is its highest terraces. These are from 100 to 125 feet above 
the river, and are usually well shown upon both sides. Their similarity 
in height on opposite sides and their very steep escarpments facing each 
other, as already frequently pointed out, indicate their formerly continuous 
extent. These upper terraces form wide plains in Bow, which have been 
partly eroded by Moore’s brook, and in- Hooksett, south of the Pinnacle 
and north from Martin’s ferry. The last of these areas extends back at 
-the north one mile from the river. ‘The greater part of its material is 
coarse gravel, and its origin seems to have been from the north-east at 
the time of the departure of the ice, differing from the ordinary fine allu- 
vium, which was slowly deposited from the floods of the main valley. 

Valuable beds of clay, extensively used for brick-making, occur in the 
highest terrace for four miles north from Hooksett, upon the east side. 
This clay appears to form a nearly continuous stratum, which has a thick- 
ness of from 20 to 30 feet, with its top about 100 feet above the river. 
It is overlaid by a few feet of sand. The upper part of this stratum con- 
sists of a hard and compact gray clay. At a depth of 10 to 15 feet this 
is usually separated, by a thin layer of sand one fourth of an inch to three 
inches thick, from the underlying d/we clay, which is soft and plastic when 
dug from the bank. A gradual transition from the gray to the blue clay 
is rarely seen. These divisions are nearly equal in amount, but in some 
of the brick-yards only the upper gray clay is exposed. Except the lower 
part of the blue clay, which is of inferior quality, both layers are well 
adapted for brick-making. Deposits of the same gray and blue clay, the 
latter always below the former, are frequently found in the south-east 
part of the state, near the coast, and along the Hudson river and Lake 
Champlain.* Two miles above the most northerly of these brick-yards, a 


* Natural History of New Vork, Mather's Geology of the First District, p. 128, etc.,and Hitchcock’s Geology 
of Vermont, pp. 157, 160, etc. 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 95 


similar stratum of clay about 25 feet thick, overlaid by 15 feet of sand, is 
worked near Bow Mills. A large alluvial area, including clay-beds, bor- 
ders Suncook river from one to two miles above its mouth. 

These deposits of clay were accumulated in very quiet water. The 
rivers which flowed from the melting ice-sheet appear to have brought 
down a greater depth of modified drift in the south part of Hooksett than 
was supplied along the distance in which the clay-beds occur. A consid- 
erable depth of nearly still water was thus held back in this part of the 
valley during the deposition of the extensive plains of Concord; and the 
same floods which deposited fine gravel and sand in Concord, carried for- 
ward clay to Pembroke and Hooksett. When this channel was nearly 
filled, and the river began to excavate the barrier below, the current be- 
came so rapid that a layer of sand was formed above the clay. 

No very extensive tracts of interval are found on the Merrimack south 
of Concord. The low terrace, lying slightly above the freshets, but hav- 
ing nearly the fertility of an interval, sometimes occupies large areas; 
but its average extent is much less than that of the high terraces or 
plains, which often come nearly to the river. From the mouth of the 
Soucook river to Hooksett the low terrace is well developed on the west 
side, averaging a quarter of a mile wide. On the east side it is narrow, 
but attains considerable width between Suncook and Hooksett, where it 
is interval. Southward to Manchester it is nowhere wide, but nearly all 
the way occupies a narrow margin on each side of the river. The Con- 
cord Railroad, along its entire length, is built on this terrace. 


7 5 Amoskeag ¢ 5 
3 
Kames. Pond. g & dam, 179. 8 8 


w, te E. 


150 ft. 
above sea. 


We seem mm eens we me ew 


Fig. 21.—SECTION IN MANCHESTER. Length, 2 miles. 


At Amoskeag falls the alluvium is two miles wide, and it averages 
thus for three miles, the city of Manchester lying at the middle of this 
distance on the east side. The largest part of this area consists of high 
sandy or gravelly plains, whose barrenness made this township, under its 
former name of Derryfield, proverbial for poverty. The Amoskeag falls 
were then utilized only as a fishing-place. The river here descends 56 
feet, from 179 to 123 feet above the sea; and its water-power has within 


96 SURFACE GEOLOGY. 


fifty years built up the largest city in the state. The plains on the west 
side are extensive, both north and south of Piscataquog river, descending 
from 280 to 265 feet above the sea. The upper edge of the alluvium in 
the north-east part of the city is from 260 to 265 feet above the sea. 
Elm street lies upon a terrace intermediate between the high plain and 
that of the depot. Wells upon this street show about 25 feet of common 
sand, in the lower part of which water is obtained by the shallower wells; 
then, 20 feet of quicksand, with no springs, beneath which is a thin layer 
of clay, lying on unmodified drift or till. The deeper wells find their 
springs between the clay and till. 

Piscataquog village also lies mainly upon an intermediate terrace, which 
extends a mile to the south, being occupied by the river road. The low- 
est terrace appears between this and the river; farther south it attains a 
large width, and is crossed by the river road at Bowman’s brook. The 
same terrace is also wide on the east side north of Goff’s Falls. 

About a mile south from the city of Manchester an extensive, ledgy 
hill, isolated in the alluvial area, lies between the Concord and the Man- 
chester & Lawrence railroads. The plain below this barrier to Goft’s Falls 
does not quite reach its normal height, being 210 feet above the sea, or 
100 above the river at the mouth of Cohas brook. In the north-western 
part of Londonderry it is slightly higher, and large quantities of its sand 
have been blown to the south-east 75 feet above it into irregular mounds 
and ridges upon the hillsides. Southward, the high plains are contin- 
uous and wide to Hudson. 

On the west side the plains are wanting most of the way for six miles 
from Bowman’s brook in Bedford to Reed’s Ferry. This side of the val- 
ley appears to have been specially subjected to the erosion of the river, 
which has in many portions removed nearly every trace of modified drift, 
leaving the till or ledge sloping to the present channel. The till is fre- 
quently exposed in the banks or bed of the river between Manchester 
and Nashua, and also sometimes appears on the surface of the extensive 
plains, showing that the modified drift has not so great a depth as in the 
widest portions of this valley northward. Nearly opposite Goff’s Falls, 
and on Sebbins brook at the south line of Bedford, the alluvium expands, 
forming three terraces, the highest in each case being go feet above the 
river. 


2 \ \ \ aC Con roocook— oh eee 
gi : 3 RIVER. 47.65 2 
7 2 s % -NoL— ¥ 207° Sekine . 
SHOWING % Noses oh é 
the Modified Drift of L\ Ve disiste rn = (Gl = 
Merrimack, ConToocook, ARN ER " bag A 
AnpAsHuetoT Rivers. ‘ TY. ee ok ' D 
04 4 is i 3 e ; e v is 
SCALE OF MILES. 7 < Fa i Aas fe \ 
as vi ‘S90 GN ar. \, x f ‘ 
lanation. = --7*~ le ag ER, KM, tb 
Edge of Glacial Drift, sovces -— ; we Jaro 
Be rhetween Terraces, —-—-\\. BF fii 2 ; e | 
Gravel ridges, or Kanes, mop = ‘ @ ooo - ite 
Ancient River beds, +-\-14-1+ \ 7 ON Sr Ac 
Roady with houses, ~~ . 2 Z wy ti 
Figures denote heights \e By. ae Sy 
mn feel above the sea. < RE ; cK 
ma iy, a 
At Z t @Ritey iS ERAN 
% A th, 5 MT. 910.\., 
g : 
S 2agN 7 Tee, INTOOCOOK- 
% SEN erat “RIVER 
Hy . LAT 4 -No2- 
of K a YL nme 
q Bio. § : 
g : 7; a Ai 
v # EP Aaa] aw & ul Fi, % 
3 e 4 i ! a e t. —, 
8 4 uf, ‘Boo. : - 218.3 Pt ee ; oe i 
; SA MW) jg f Ny Soe 
all VE Lee © eR NA z 
% stints Le? ‘ a @ \ 2 
anh 220 (\ {i : “ \ bs 3 ° 
: Th E Ay = 1 Ord; ol j Ms k 
3 20 TS wfen | ER aed i ei @ 
§ oT \\ 2 u W 
2 7 i [ene \ 
£ @ p XN I . [¢) 
© * > wy ‘200\ x 195. : : \ z 
220. > ys a amd ” i caer 
Sj We YY | L¢ 
B<] x rn ‘BR. Ja 1 
Ts eee eMICHUCK //c'ieh m0. Y. X \, oy | 
a => g » \. . \ 
- 1S ‘\ ‘ 
EH 190. R as A on Ag ies 
2 Seok LAI, ? , f E : 1 el 
vom FRON\ d 
NE \S10- 480 a . i ees WLS 
5 Lhe aa Sieh 
i yes \ a ge 
i 
é ! 
Be yy 180. iy ¥ tad ; 
K E\ ‘& IN i eo sy \) 9 & NY eae 
: Z SNE | Bot. \ fot 
ao NEw kee Molt) BEEP AT LO 
Ra x {eons ; as 5 | I : a Cat 
BS i 1 fe * , orth P| 
Ss , ° SH & 'P ‘ fe) 
cas : 
§ i Niederelt F Mag ceee 4 \ : 
‘ A = a s Tz. i eg 
Asuuezor Rivers] “i % MERRIMACK: : : yy 
. EN, of -RIVER>- ANON || ¢ Se C9 rs 
icinity of % c BL eae » 3 : x 
KEENE. g pe y [Nes dp , at ie 4 AON “Diines, 950) 
: oe i 


HELIOTYPE_ 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 97 


In Litchfield and Merrimack the high sandy plains have a larger devel- 
opment than in any other portion of this valley excepting Concord. On 
the east side we find the modified drift occupying almost the entire town- 
ship of Litchfield. An area from one fourth to three fourths of a mile 
wide next to the river is the low fertile terrace-—which is partly interval, 
as opposite the mouth of Souhegan river, but mostly lies somewhat above 
high water. East of this is the plain, about 100 feet above the river, co- 
inciding in its eastern boundary nearly with that of the township. Its 
greatest width is opposite Thornton’s Ferry, where it extends three miles 
back from the river. Its surface is in general very level ; a depression is 
partly occupied by Darrah, Halfmoon, and other ponds. This wide 
alluvial area becomes narrowed to two thirds of a mile after entering 
Hudson, but again expands about Otternic pond, which is surrounded by 
plains. Two miles farther south, below Nashua, this area is contracted 
to only one fourth of a mile at each side. 

The plains of Merrimack extend five miles southward from Reed’s 
Ferry, having the same height as on the east side, and extending back 
nearly two miles from the Merrimack at their widest portion, which is 
along Souhegan river to Burnap bridge. Below this the alluvial area 
averages a mile wide nearly to Pennichuck brook, on whose north side it 
is interrupted by till which extends almost to the river. More than half 
of this width is occupied by the plains, which are mostly very level, with 
scarcely any elevations above the general surface, but having occasional 
hollows that often enclose small ponds. A considerable portion of the 
plain at one mile south from Thornton’s Ferry has undergone erosion to 
the amount of 25 feet, now remaining 75 feet above the river, At the 
south-west part of this terrace clay deposits, which have been used for 
brick-making, occur near two small ponds. A single low terrace, one 
third of a mile wide, lies between the southern extension of these plains 
and the river. 

From Reed’s to Thornton’s Ferry, two terraces are well shown below 
the plains. The north part of Souhegan village, and the road farther 
south, lie upon the higher of these, which is about 60 feet above the 
river. A succession of five terraces was observed south of Naticook 
brook at Thornton’s Ferry. The river here is 100 feet above the sea, 


and the terraces are 20, 35, 50, 75, and 105 feet above the river, the first 
VOL. Ill, 13 


08 SURFACE GEOLOGY. 


being interval, and the last the high plain. They all extend southward 
beyond the village, except the second, which terminates a short distance 


125. Old 
channel. 


6 
° 
7 
% 


140. 


E. 


too ft. 
pre above 


Fig. 22.—SECTION IN MERRIMACK AND LITCHFIELD THROUGH THORNTON’s “~~ 
Ferry. Length, 34 miles. 


south-west of the depot. The third represents the immediate terrace 
which we noted as commencing at Reed’s Ferry. The lower terrace 
along this distance is now in large part above the reach of the annual 
floods; but its undulating surface, very noticeable along the railroad, 
shows that nearly every portion of its area has been at some time occu- 
pied by the constantly varying channel of the river. The crescent-shaped 
pond north of Naticook brook lies in an ancient river-bed; another an- 
cient channel, considerably above that of the present day, is crossed 
shortly after turning off from the main road in Litchfield to go to Thorn- 
ton’s Ferry. At the east landing of this ferry the bottom of the bank is 
a thick stratum of clay, which is overlaid by sand. 

Through Nashua we find the width of the alluvium narrowed, and till 
extending at several places almost to the river. An isolated area of till 
lies close to the railroad just south of Pennichuck brook. A former 
channel of this brook is plainly traceable here for a mile; it.is crossed by 
the railroad a short distance south of the bridge, and thence extends 
southward, forming a long, nearly straight hollow in the terrace between 
the railroad and the river. A short distance farther south a succession 
of four terraces appears, at heights of 30, 55, 65, and 95 feet above the 
river. The highest of these forms a plain, over which the road next to 
the river extends for a mile south from Pennichuck brook. A small peat- 
bog lies in a depression on the west part of this plain. Two thirds of a 
mile north of Nashua river a narrow area of till extends almost to the 
Merrimack. Much of the till of this section is quite different from that 
usually seen, as it contains very few large boulders: its coarser portions 
are mainly pebbles and chips of rock, not often exceeding one foot in size. 
The former were derived from the neighboring Lake gneiss at the north, 
and the latter from the compact mica schist and quartzite of the Mer- 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 99 


rimack group. The kames of Nashua and Hudson differ in the same 
way in respect to their material from those farther north. South of the 


roo ft. 
above sea. 


Fig. 23.—SECTION IN NASHUA AND HUDSON, 4% MILE 
NORTH FROM THE MOUTH OF NASHUA RIVER. 
Length, 2 miles. 


till mentioned three terraces occur. The middle one corresponds in 
height to the extensive plain of the south part of the city, whichis 150 
feet above the sea, or 57 feet above Merrimack river. This plain aver- 
ages two miles in width for three miles west from the Merrimack, to 
Mine falls on Nashua river. It lies mostly on the south side of this river, 
and also includes the last three miles of Salmon brook within its area. 
The water-power of Nashua is supplied by these streams, the utilized fall 
of Nashua river being 51 feet, and that of Salmon brook 57 feet. 

The origin of the material of this plain was partly from each of these 
streams and partly from the north-west, along the avenue followed by the 
Wilton Railroad. Salmon brook has considerable alluvial deposits along 
its whole course. Very interesting kames occur along this brook in Dun- 
stable and in Groton, Mass. They extend several miles, lying north and 
south, and are well seen from the Nashua, Acton & Boston Railroad. It 
appears that these were formed when this was one of the principal outlets 
from the melting ice-sheet. After the full disappearance of the ice the 
direction of drainage was changed, and a part of the deposits of this area 
has been carried back northward by this brook. 

Main street in Nashua, at the city hall and at the Worcester depot, has 
the same height with the dam at Mine falls (152 feet above the sea). 
The descent of the plain eastward in this distance is about 20 feet. 
Three miles farther south-west, upon the Nashua river in Hollis, we find 
plains 50 feet higher, or 70 feet above the river, which has a wide alluvial 
area on both sides to Massachusetts line. Kames, which were probably 
formed by waters flowing south from the melting ice, occur in Nashua 
just north of Hollis station, and on the east side of the railroad at the 
next crossing to the north; and others, previously mentioned, lie near the 
river, a mile farther north. One of the finest displays of kames to be 


JOO SURFACE GEOLOGY. 


found in Massachusetts is shown near the head of Nashua river, along 
the railroad between Fitchburg and South Ashburnham. These kames 
lie in north-west to south-east ridges parallel with the valley. When 
they were being formed we must suppose that the ice had gone from the 
lower east and north-east portions of the river’s course, and that the 
floods of water supplied from the melting ice-sheet at its source were 
then completing the deposition of these extensive plains at its mouth. 

At the same time floods were here poured into the Merrimack from 
the north-west, where no stream now exists. A continuous belt of allu- 
vium, upon which the Wilton Railroad is built, extends six miles from 
the Souhegan river in Amherst to the plains of the Nashua river. Its 
narrowest place, three miles from the city, is a third of a mile wide, 
while its widest portions, in the north-west corner of Nashua and south 
part of Amherst, are a mile and a half wide. These plains show a grad- 
ual descent from north-west to south-east, amounting to 75 feet in the six 
miles. They consist of levelly stratified sand and gravel, and in general 
have a very regular surface; but several ponds, often with no outlets, 
fill depressions upon their widest portions, as Stearns pond in Amherst, 
Pennichuck pond near South Merrimack, and Round pond in Nashua. 
Deposition probably took place very rapidly from floods which brought 
down the material from the melting ice-sheet. In some cases masses of 
ice may have remained where we now find these ponds, or they may be 
due to an unequal supply of material and varying currents. The waters 
of the Souhegan valley at this period found their way to the Merrimack 
by three routes. One was along the present course of this river, which, 
below its extensive plains in Amherst, is narrowly enclosed at two points 
by high land of till or ledges; a second, similar to the first, was along 
Pennichuck brook; while the third, which differs from the others in its 
ample. width and, direct course, brought the greater part of these floods 
to the same mouth with the Nashua river. In this way the flood-plains 
of the last route appear to have become slightly higher than along the 
present Souhegan river and Pennichuck brook, which therefore became 
the channels of drainage after the Champlain period. 

A half mile below the mouth of Salmon brook, hills approach nearly to 
the river, beyond which is a plain of similar height with that south of 
Nashua river. In the remaining three miles to Tyngsborough the allu- 


MODIFIED DRIFT ALONG MERRIMACK RIVER. IOI 


vial area on the west is narrow, consisting principally of the low terrace, 
which is about 25 feet above the river. Plains of considerable extent 
occur on the opposite side, 50 to 75 feet above the river. At Tyngsbor- 
ough the alluvium is wholly cut off on the west, and nearly so on the 
east, by hills of ledge or till. 

Five miles south of the state line, the Merrimack river turns to the 
east at North Chelmsford, and thence pursues a devious east and north- 
east course, at right angles to its valley in New Hampshire, about thirty- 
five miles to its mouth three miles east of Newburyport. South and 
south-east from its bend are extensive low alluvial plains. These were 
deposited by the floods from the melting ice-sheet in New Hampshire, 
which kept their course south-east to Massachusetts bay. These plains 
form the very low water-shed between Lowell and Boston, and are the 
continuation of the slowly descending ancient flood-plain, which we have 
traced in the upper terraces of Merrimack river through New Hampshire. 
When these extraordinary floods abated, the river found a lower channel, 
which had been mainly sheltered from the deposition of modified drift by 
its crookedness and closely bordering hills. 

The area here crossed by the river is remarkable for peculiar accumu- 
lations of till, which forms steep, smoothly rounded oblong hills 100 to 
200 feet in height. These are set almost as thickly as possible over an 
otherwise nearly level country. Their prevailing trend, especially north 
of the Merrimack, as in South Hampton and Kensington, is north-west 
to south-east, or approximately parallel to the motion of the ice-sheet, 
which must have heaped them up beneath its mass, and left them at its 
melting in their present form. The next chapter will contain a full de- 
scription of these hills, which occur occasionally in many portions of 
New Hampshire. 

At the mouth of Merrimack river a ridge of sand, 25 to 50 feet high 
and 10 to 40 rods wide, extends several miles both to north and south, 
facing the ocean. Its gentle east slope forms the beaches of Salisbury 
and Plum island. This portion of the sand brought down by the river 
has been swept back again by the waves, and lifted above their reach by 
the wind. Marshes a mile wide lie on the west side of this ridge. These 
recent deposits will be described, with those of the coast northward, in a 
later portion of this chapter. 


102 


SURFACE GEOLOGY. 


RECAPITULATION OF MopiFieD Drirr oF PEMIGEWASSET AND MEeErRI- 
MACK RIVER. 


Distances in 
miles from Pro- 


HEIGHTS IN FEET ABOVE THE SEA. 


file lake. 
» » ‘ 
PLACES. g = 3 
Ba 
oe Ey u i 3 4 Altitudes for reference, and remarks. 
O39 eS 3 a9 
Bo | 25 2 Be 
A Oo 4 q 
Mouth of East Branch, g.2 9-3 710] ad oe No Premanene tributary deltas occur in this 
valley. 
12. 12. 62 5| Profile lake, about 1950. 
Wosdstock, 5 4 7 a Woodstock town-house, 734; bridge, 649. 
68<. E West Thornton bridge, 596. 
West Thornton, 15.5 15.8 576 Ss Ww. Livermore Falls bridge, 561; dam, 511. 
690, W. Plymouth railroad station, 490. 
635, E ed Senons 562. 
i th, . 1765 17.8) 6: ? .7'| New Hampton bridge (centre), 462. 
aimiles south; a 7 pea 660, W.! Bristol station, 369; Main St. bridge B 
6 Be, 4 
sige ae 3 K 3°. | Newfound lake, 590. 
4 19+5 = 555 6 See Railroad bridge, Smith’s river, 336. 
aan = El ston, 335, ; Papi 33 
West Campton, . Be: 226% 0 { » .7'| Franklin sta,, 363.26; bridge (centre), 304. 
pen a a4 630, W. Jane of N. R.R. and Bristol Branch, 364. 
6 E ebster Place station, 295. 
3 miles south,. . 24.7 25.1 520 mics Ww. North Boscawen station, 290. 
» "'+| Boscawen station, 274. 
Fisherville, railroad bridge, 268. 
Livermore falls, . 26.3 26.8]! 505-483 600, E.| W. Concord sta., 353; E. Concord sta., 246. 
Concord station, 252.39; state house, 292. 
Param for city levels (called 0), 225.29. 
PI this 28,2 28.8 68 —570, E.| Top of city water-works dam, 412. 
pepe 4 Banreze Railroad bridge, Merrimack river, 247. 
560, E is 7 Sah river, 221, 
th line of Plymouth 1 2. 6 { 350 i uncook river, 243. 
South line of Plymouth, 3 3772 493 525, W-| Hooksett sta., 206; R.R. bridge south, 205. 
Martin’s Ferry station, 199 
Ashland, . .... 33 34.5 459 565| Amoskeag Falls dam, 179; flash-boards, 181. 
525, E.| Manchester station, 180.83. 
i 540, W.| Datum for city levels (called 0), 108.98. 
2 miles south, . se 35 36.5 450 Dunes, | Massabesic lake, 256. 
825, E.| Manchester & No. Weare R. R. bridge, 169, 
Goff’s Falls station and bridge, 146. 
New Hampton, 39 4r 438 520! Reed’s Ferry station, 137. 
Rautoad bridge, Souhegan river, 128. 
. o2, N. ornton’s Ferry station, 125. 
Bristol, 42.8 45-2 352 i E,| Railroad bridge, Pennichuck brook, 127. 
Pianos Pavien) Concord i autesd, 123. 
ais te Datum for city levels (called 0), 93.10. 
Mouth of Smith’s river, 44.8 47°5 320) 460, W.) Reservoir of SAN ied es a 2" 
Nashua & Rochester Railroad bridge, 126. 
: 480, E.| Pawtucket Falls dam, Lowell, 87. 
Hill, . . 48 Sr 3095 te W.| Essex Company’s dam, Lawrence, 39. 
. 466, E.| _ This river is affected by tide to Mitchell’s 
Mouth of Salmon br’k, | 51.5] 54-7]| 300] { 475-485) | falls, 234 miles above Haverhill, Mass. 
Along Contoocook River. 
: 440-420, E. 
Franklin, . . 54.6 58 || 295-269] ) 445-430, W.| Mouth of river, Fisherville, 249. 
430-550, E. Borough dam, about 355. 
430, N. W.| Mast Yard station, 374. 
Webster place, 57 60.7 260 Dunes, Contoocook station, 8933 
joo, E. Hives. above do., about 365. 
385, E. est Hopkinton station, 392. 
North Boscawen, 60 64 256 {ee W.| Henniker station, 439. 
River below Henniker, 389. 
6 68 neo) § 370-360, E.| Foot of Long fall, 433; head of do., 546. 
Boscawen, . - as “4 5211 340-310, W.| Hillsborough Bridge station, 574. 
e Beek and meee of falls in the river at Hills- 
3 i 340-320. q orough Bridge, 564-591. 
Fisherville, 66 TES 249 ee w. at Bennington, 606-676. 
ef orth Peterborough 714-724. 
«* Peterborou 27-734. 
West Concord, 69.5 75-5 229) 355-359] Peterborough station ve ai 
River at county line, about 875. 
350, E.| East Jaffrey station, T0532, 
Concord, . 7 79°5 237, 367, W.| 3 ponds in north part of Rindge, each 1114. 


MODIFIED DRIFT ALONG MERRIMACK RIVER. 103 


Distances in 
miles from Pro- HEIGHTS IN FEET ABOVE THE SEA. 
file lake. 
o vo ro 
PLACES. Z 4 8 
ae | & 
a o 5 “ % B Altitudes for reference, and remarks. 
Cie to 
A Oo 74 Bi 
Mouth of Soucook river, 76 3 85.3 199 { ea ao In the Lake District.* 
, , WwW. 
E Mouth of Wron tpibcoeee cay 269. 
305-315, -| Cross’s mill-pond (Win. river), 415. 
Suntooks a8 ~t 78.6 Be 198 325, W.| Tilton station, 458; Winnipiseogee Compa- 
E ny’s pond (Win. river), io; i: 
315-290, I.) East Tilton station, 499; Little bay, 473. 
HOOKSetE wap: 42a 89: pe | roz te { 325, W.| Sanbornton and Great bays, 490. , 
3 OF Round bay, Taconis sor ) 
in’. 312-29: -| Winnipiseogee lake (high water), 513. 
MarhnsiM erty ae Bans 94 to { 295, W.) Meredith Village station, 556. , 
80, E Wukawan lake and Long pond, 549. 
F 260, &./ New Hampton station 578. 
Sumiles RUE ene oe 96 ase as W.| R. R. summit2 ms. S. E. from Ashland, 679. 
Squam and Little Squam lakes, 569. 
Manchester, . . . . 89 99 179-123} (eee: He 
. 280-265, W.| Siope of the highest terrace in Merrimack 
Valley. 
» 2to, E, 
Goff’s Falls, . . . . 92-5] 102.6]| 119-110] oe Ww. as Fe per 
, 210, E.| From mouth of East Branch : 
Reed’s Ferry,. . . 96.5] 106.8 704 (ai. *w.| to south part of Thornton, . | 10 15 
«« Livermore falls, 7 4 
“ 
Thornton’s Ferry, . . 98.7] 109.2 100] ae oF afi oe oe = 73 
“Mouth of Smith’s river, . | 12 9 
« 
Mouth of Pennichuckbr., I0l.3 12 96] 190] ¢ North eee brook, $4 5 
fe se 
“* Hooksett, . . . | 20% 3 
“ 
Nashua,. . . r 104 114.7 93 180-170| «« Nore eae. cava: ee a 
“« Thornton’s Ferry,. . 6 2 
“ i 
Stateline, . . . 1. 108.3) 119 go 175-150) Stateline, s 9% 4 
Total distance, . . .| 99 6.2 


Mopir1rep Drirt aLonc Conroocook RIvErR. 


The modified drift of Contoocook river, mapped on Plate V (p. 96), has 
been explored for a distance of forty miles from the east line of Jaffrey to 
its mouth. This is the largest tributary in the state. It gives the best 
example found within our limits of a long valley descending from south 
to north. The upper twenty-five miles of the distance explored has a 
quite straight course a few degrees east of north. At Henniker the 
river turns eastward, and thence flows slightly east of north-east fifteen 
miles to its junction with the Merrimack at Fisherville. These distances 
measure the direct course of the valley, not the meandering channel of 
the river, which exceeds fifty miles. 

From the northward course of this valley, we should suppose that the 


* These heights were determined by levelling from Franklin station by Winnipiseogee lake to Ashland, and 
thence along Pemigewasset river to the point of beginning. By this complete circuit they were proved to be 
correct, as compared with the altitudes given in Vol. I, p. 258, and also here, for Franklin and Concord. 


104. SURFACE GEOLOGY. 


conditions which prevailed at the melting of the ice, and the modified 
drift then deposited, would differ from the common type. This expecta- 
tion was fully justified by exploration for thirty miles, along which dis- 
tance deposits were found different from any seen elsewhere in the state, 
together with frequent kames; and it is only after entering Hopkinton, 
and along the last ten miles of the river, that it is bordered by the ordi- 
nary level and continuous alluvial plains. 

We will first describe the modified drift of this valley in order, pro- 
ceeding from its source to its mouth, without intruding any theories; 
after which, we will seek an explanation of the facts observed. Several 
ponds in the north part of Rindge constitute the head waters of Contoo- 
cook river; and others in the same town are among the principal sources 
of Miller’s river. The water-shed on which these ponds lie is a compara- 
tively level plateau, partly covered by large amounts of coarse, water- 
worn gravel, and elevated 1,100 to 1,200 feet above the sea. 

At the line between Jaffrey and Peterborough, where our special exam- 
ination of the valley began, the river is about 875 feet above the sea. 
For the first mile the stream is bordered by coarse, water-worn gravel, 
containing pebbles one to two feet in diameter, interstratified in nearly 
equal proportion with sand. These deposits occur in ridges or irregular 
terraces, which reach a height of 150 feet above the river. They are 
well exposed by the excavations for the railroad, along which they ex- 
tend, decreasing in height at the north, to within a half mile of Noone’s 
mill, Thence northward to Peterborough village the principal deposits 
on the west side are sand, which slopes very irregularly from the river 
to the height of 100 feet at the distance of a quarter of a mile on the 
hillside. This was seen in some places to be stratified conformably to 
the surface, and it is scarcely anywhere distinctly terraced so as to show 
steep escarpments with a wide, level top. Boulders of various sizes, up 
to four or five feet in diameter, are frequently found embedded in this 
stratified sand. 

South-east from Noone’s mill we find an interesting assemblage of 
kames, in irregular ridges, which rise from 50 to 75 feet above the river. 
These are three or four in number, lying approximately north and south 
and parallel to each other. Their material is water-worn gravel, contain- 
ing pebbles up to a foot and a half in diameter. At one point a ridge 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 105 


turns abruptly from a northward to an eastward course, enclosing a pond 
in the triangular hollow between it and the adjoining ridge. A short dis- 
tance to the north is a hill, about 90 feet above the river, which appears 
to consist of till overlaid by a gravel deposit. This is surrounded by low 
alluvium. A little farther north the river flows at the eastern foot of a 
gravel ridge, which is about 40 feet in height. A boulder six feet in di- 
ameter was noticed in this ridge; but such blocks are very rare in these 
kames, and were nowhere seen in the high gravel deposits farther south. 

One mile east from Noone’s mill, sand dunes occur on the hillside at a 
height of about 200 feet above the river, covering some two acres, which 
are almost destitute of vegetation. 

The Contoocook, at the mouth of Nubanusit river in Peterborough 
village, is 734 feet above the sea. Here till and ledge rise steeply on 
the east side, which has no modified drift. Half a mile to the north a 
considerable width on this side is occupied by alluvial sand and fine 
gravel, which extend in irregular slopes to 100 feet above the river, rarely 
showing any steeply-terraced or level-topped surface. The most irregu- 
lar portion of this area is at the cemetery, which is diversified by kame- 
like mounds and ridges. As we approach North Peterborough the till 
and ledge again reach to the river. Along this distance on the west 
side, similar sand and gravel, in irregular slopes, thinly cover the hills to 
a height of 100 to 150 feet above the river. Occasional boulders are 
found enclosed in these deposits. 

At North Peterborough a broad, terrace-like ridge of sand extends half 
a mile on the north-west side of the river. This has steep slopes, but its 
top is nearly level, with a height about 100 feet above the river, being at 
the south 820 and at the north 810 feet above the sea. The valley here 
bends for a short distance to the east, so that to one following the river 
northward this ridge at first appears to lie as a barrier before it. With 
this huge sand-bank the high deposits of modified drift, which we have 
found bordering this river continuously for five miles, come to a sudden 
end. 

Half a mile eastward a small terrace, about 50 feet above the river, 
lies on its east side. Excepting this, we find in the next two miles only 
low alluvium, which averages a half mile in width, lying mostly on the 


east side of the river, with a height of 10 to 30 feet above it. Beyond 
VOL, III. 14 


106 SURFACE GEOLOGY. 


this we find the valley for the next six miles, extending nearly to An- 
trim, well-nigh destitute of any alluvial or terraced deposits; yet it has 
along most of the way an ample width with gently sloping sides, which 
are usually the conditions for the accumulation of extensive plains. In 
this distance, and for several miles farther north, the descent of the river 
is small, amounting to 123 feet in the sixteen miles between North Peter- 
borough and Hillsborough Bridge. More than half of this occurs at Ben- 
nington, where its fall is from 676 to 606 feet above the sea; for the rest, 
the average slope is about three feet to a mile. 

The only important deposits of modified drift seen along this river for 
six miles were kames, which appear on the east side near the north line 
of Peterborough, and are very well shown upon both sides of the valley 
at one mile south-east and south-west from Bennington. In the north 
edge of Peterborough these consist of sand or fine gravel, which lie in 
numerous mounds and ridges, in depths to 20 or 30 feet, upon a sloping 
hillside of till go to 100 feet above the river. These deposits are irregu- 
larly stratified, conformably in some places, and perhaps generally, to the 
underlying surface. They contain here and there embedded boulders, 
the largest of which observed was four feet in diameter. 

From a half mile to more than a mile south of Bennington, on both 
sides, we have large accumulations of kames. On the west they rise to 
about 140 feet above the river, and consist of sand in hillocks and north 
and south ridges, which are 50 to 75 feet in height, lying on till. In the 
sand, which is irregularly stratified as seen in many places, there also 
occur occasional boulders up to four feet in size. On the east side these 
ridges and banks are well shown along the road to Greenfield before 
coming to Whittemore pond. They are composed in large part of the 
‘coarse, water-worn gravel which is characteristic of the kames, inter- 
stratified with sand, and containing embedded boulders. These deposits 
reach a height fully 175 feet above the river, or 850 feet above the sea. 
Thence to the south-west similar deposits border the north and west 
sides of the hills to within a half mile of Pollard pond, being well shown 
on the east side of the Manchester & Keene Railroad, now being built, 
for one mile south from Bennington station. Here they form nearly 
level terrace-like banks of fine gravel or sand, 170 to 175 feet above the 
tiver, irregularly stratified and rarely containing boulders, 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 107 


At Bennington station the kames are very well displayed, forming 
long and narrow steep ridges. One of these has been here cut through 
for the railroad, and shows very instructive sections. Its base is 40 
feet above the river, and its height about 20 feet. Fig. 24 shows the 
simple transverse section at the south side of the cut; and Fig. 25 shows 
the section on the north side. 
The east portion of the last is 


E. Ww. ‘ 
directly transverse, but its west 
Sa a portion is a longitudinal section, 

ig, 24.— SOUTH SIDE extending farther north. 


Fig. 25.—NORTH SIDE. 
SECTIONS OF A Kame, BENNINGTON Station, M. & K. R. R. 
Scale, 25 feet to an inch. 


This kame showed the following succession of deposits, beginning at the top: 


1. Coarse yellow gravel, containing pebbles up to 8 inches in diameter ;—thickness, 
3 to 5 feet. 

2. Fine sand, whitish and yellowish ;—thickness, 3 to 5 feet. 

3. Coarse dark gravel, containing pebbles up to one foot in diameter ;—thickness, 
3 feet. 

4. Sand, same as No. 2, obscured at bottom by crumbling of the bank ;—thickness, 
4, perhaps 8, feet. 

A-A. Downfall of strata, with irregular, broken steep slope, against which lies an 
accumulation of sand. 

B. Depression of 2 feet, similar to the foregoing (not extending to south side). 

F. Fault, seen only on south side ;—dislocation of strata, 6 inches. 


Boulders up to seven feet in diameter are rarely found on the top of 
this kame; but none were observed embedded in it. It will be noticed 
that the alternate layers of gravel and sand preserve a nearly uniform 
thickness throughout the excavation. It should be added that the gravel 
usually contains no clear sand and the sand no gravel; and that these 
succeed each other by a sudden change, not by gradual transition. These 
sections appear to show the deposition of two years, the coarse gravel 
being brought from the melting ice-sheet by strong summer floods, and 


108 SURFACE GEOLOGY. 


the sand being deposited in autumn and spring. The line of downfall, 
A-A, appears to show where these materials at first rested against a wall 
of ice. When this melted, the strata suddenly fell as seen at these 
points. 

In Hancock, a mile and a half farther west, the first excavation for this 
railroad after crossing the highway shows sand and fine gravel under- 
lying till upon both sides of the cut. (Fig. 26.) This is on the south 
slope of a hill, at a height for the bottom of the cut of 28 feet above the 
river. The surface all around is composed of till and covered with 
boulders. The separation between the modified drift and till is not a 
definite line; but there is a gradual transition, occupying one or two 
feet, and the till has thin streaks of sand. No’ boulders were seen in 
the underlying deposit. 


Fig. 26.—SECTION OF MODIFIED DRIFT UNDER TILL, 
HANCOCK. 
Length of Section, 300 feet; height, 15 feet. 


1. The unmodified drift, or till, contains boulders of all sizes up to 8 or Io feet; its 
thickness is from 6 to Io feet. 

z. The modified drift is stratified in layers of varying thickness; sometimes con- 
torted, but mainly horizontal; consisting of sand (in strata from 2 to 5 feet thick) and 
fine gravel (with the largest pebbles 3 inches in diameter) ; thickness exposed, from 5 
to 7 feet, also extending below the excavation. 


The lack of alluvial deposits in the Contoocook valley is made up 
where we might least expect it, two miles farther east, at a height of 
nearly 200 feet above the river, and not in the pathway of any large 
stream. Following the stage road from Bennington to Greenfield, 
numerous kames were seen north-east from Pollard pond, principally 
forming north-west to south-east ridges, and composed of coarse gravel. 
The road next enters on a nearly level plain of sand and gravel, which 
extends about two miles to the south, being from one half mile to one 
mile wide. Its height is from 850 to 870 feet above the sea. Hog- 
back and Bridge ponds lie in depressions of this plain, with steeply 
sloping shores from 25 to 30 feet high. Pollard pond lies about 50 feet 
below the plain, of which with its outlet it forms the western boundary. 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 109 


The first of these ponds has its name from gravel ridges or kames. 
These are well shown between this and Pollard pond, extending in north- 
west to south-east ridges, not higher than the plain, but shown as ridges 
because of intervening hollows, These kames, with most of the plain 
northward, consist of coarse, rounded gravel, with the largest pebbles 
from a foot to a foot and a half in diameter. Southward, sand predomi- 
nates, but much kame-like gravel is also found. These materials are 
spread out comparatively level, but the excavation for the railroad shows 
that they have usually an oblique stratification, dipping mostly to the 
south-east. Greenfield village lies at the east edge of this alluvial area, 
which extends with its full width a half mile farther south. In this dis- 
tance we find, on the east side of the railroad, kames containing pebbles 
up to a foot and a half in diameter, and lying in north and south ridges 
20 to 30 feet higher than the plain. These continue along the railroad 
fully a mile to Cragin pond, forming a narrow belt, which is bordered by 
hills of ledge or till. Their southern portion is mainly of sand or fine 
gravel, and they terminate in a sand plain, which lies on the east side of 
this pond, 25 feet above it. 

A water-shed scarcely higher than this plain and lower than the kames, 
being 863 feet above the sea, separates Cragin pond from the head-stream 
of Stony brook, which the railroad follows to Wilton, descending more 
than 500 feet in nine miles. The modified drift of this valley consists 
of occasional terraces and kames, but presents no remarkable features, 
and is scanty in amount. 

No streams now exist, or can have existed with the present system of 
drainage, capable of forming the large alluvial plain of Greenfield. Ex- 
cepting north of Pollard pond, the hills which lie between it and the Con- 
toocook do not exceed the plain in height. Its extent along the outlet of 
Pollard pond is to the north-east corner of Peterborough, below which for 
two miles this stream is destitute of alluvium, as are also the low hills and 
even the valley of the Contoocook on the west. 

At Bennington the valley is closely bordered by hills, beyond which 
we again find the modified drift continuous to Hillsborough Bridge, a 
distance of nine miles. The Hillsborough & Peterborough Railroad, 
now being built, is here on the east side of the river, and from South 
Antrim northward lies on a low and partly swampy plain 15 to 20 feet 


IIo SURFACE GEOLOGY. 


in height and a fourth to a half mile wide. The old muster-ground of 
“Cork plain,” in Deering, is a part of this long terrace. On the west 
side the river has a similar but narrower alluvial margin, principally of 
meadow or interval, not exceeding 10 to 15 feet in height. At the north 
line of Antrim and Deering these deposits have their widest development 
upon both sides, covering a mile square. se 

Kames extend along the east side of this low alluvium from opposite 
South Antrim to the north line of Bennington. They are disposed in 
numerous mounds and ridges, which lie mostly north and south, attain- 
ing a height of 100 feet above the river, and occupying a third of a mile 
in width. Their material is sandy gravel, with the largest pebbles about 
one foot in diameter, but they contain, also, occasional angular boulders 
of sizes up to five or six feet. Near their north end the surface of ordi- 
nary till between these gravel ridges is strewn with massive boulders 
often ten feet in diameter. Kames are also found a half mile south-east 
from Hillsborough Bridge, in mounds 10 to 30 feet high. 

A very remarkable accumulation of sand and gravel is found on the 
east side of this valley in Deering, two and a half miles south from Hills- 
borough Bridge, at a height of more than 300 feet above the river. On 
its north-west side an abrupt spur of Hedgehog hill, probably 450 feet 
above the river, projects half-way across the valley; and the same range 
rises still higher on the south-east. The deposit lies upon the south- 
west slope of the intervening hollow, reaching to the height of land 
which separates the hills. It consists of sharp-grained sand, interstrati- 
fied with gravel, which contains pebbles up to six inches or nearly one 
foot in diameter. Four or five acres at the top are nearly level, and 
thence a long slope extends down nearly to the alluvial plain. The 
stratification of this sand and gravel is seen in gullies formed by rains 
or very small springs, which are making slow inroads upon the level 
area at the top, where the undisturbed strata are exposed, dipping to 
the south-west nearly at the same angle with the slope of the hill. No 
boulders were observed, either embedded or on the surface. This is the 
only high deposit of modified drift close to the river in this portion of its 
valley, and must be of different origin from our ordinary high terraces 
and plains; nor does any water-course exist by which it could be brought 
here. 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. III 


Other notable deposits of sand and gravel, to be hereafter described, 
occur at nearly the same level on both sides of this valley through Hills- 
borough county. They are usually two or three miles distant from the 
Contoocook river, but in most cases border some tributary stream. 

At Hillsborough Bridge the river is enclosed on both sides for a short 
distance by slopes of till. Below this place the alluvium forms low plains 
between the railroad and the river. The fall of the Contoocook at Hills- 
borough Bridge is 27 feet, its height at the head of this fall being 
591 feet above the sea. At the head of Long fall, near the line between 
Hillsborough and Henniker, it is 546 feet above the sea, and in the next 
two miles it descends 113 feet through a narrow valley destitute of modi- 
fied drift. 

In Henniker a small terrace 15 feet above the river is crossed by the 
railroad near the foot of Long fall. A wider terrace, 30 feet above the 
river, extends nearly a mile from the west village to the railroad bridge. 
These are both on the north-west side, and are the only deposits of mod- 
ified drift west of the principal village. At the east side of this village 
an interesting assemblage of kames is found, consisting of water-worn 
gravel, with the largest pebbles one to two feet in diameter, in three or 
four north and south ridges, 20 to 50 feet in height, nearly parallel with 
each other. They cover an area two thirds of a mile long and half as 
wide, and rise to a height of 100 to 125 feet above the river, which below 
the village is 390 feet above the sea. It will be seen that these ridges lie 
at right angles with the course of the valley, extending nearly across it, 
and causing the river to flow around them in a southward bend. East 
from the kames the river flows through intervals or low plains, 15 to 40 
feet in height, which extend, with an average width of two thirds of a 
mile, through the township. 

_ Two and a half miles east from Henniker village we find on the north 
side of the river, south-west from Whittaker pond, another group of 
kames lying in north and south ridges across the valley like the preced- 
ing, and reaching a height of 100 to 150 feet above the river. The mate- 
rial of these ridges is in part the usual water-worn gravel, but in some 
portions it contains principally angular fragments of rock one to three 
feet in dimensions. Whittaker pond is bordered on the south by a nearly 
level deposit of coarse rounded gravel, about 75 feet above the river, 


II2 SURFACE GEOLOGY. 


Half a mile south-west from these ridges, on the south side of the 
river, we find a remarkable kame, half a mile long, with a course a little 
to the east of south, composed of sandy gravel, with pebbles frequently 
six to eight inches, but not commonly exceeding one foot in diameter. 
This forms a steep ridge about 100 feet above the hollow which separates 
it from a high hill an eighth of a mile west, and 125 feet above the low 
alluvium, which extends two thirds of a mile wide on the east. A small 
pond lies in this alluvium at the foot of the kame. The next third of a 
mile south shows no ridge, but it is succeeded by a very interesting mo- 
raine, which forms a steep and narrow crescent-shaped ridge, fully half 
a mile long, lying in a similar position with the kame between the hills 
and the low alluvial area. Its course is to the south-east and east, with 
height descending from about 75 to less than 50 feet above the alluvium, 
and it is separated from the hills by a hollow nearly as deep. The crest 
of this moraine consists almost entirely of angular boulders of all sizes 
up to ten feet in diameter, which cover the surface and are piled as 
thickly as possible, with scarcely any space for finer material. On the 
sides, and along the top near the east end of the ridge, we find earth and 
boulders intermixed in the ordinary proportions of the coarse upper till. 
These blocks are principally of two kinds, derived from the Lake and 
porphyritic gneiss, which occupy the whole country for more than ten 
miles to the north. The New Hampshire Central Railroad, now discon- 
tinued, was built in the hollow on the south-west side of both kame and 
moraine. 

A noticeable feature of the Contoocook basin is, that its east and south- 
east water-shed is formed by high, irregular hills near the river, which 
has no large tributaries from this side. The lowest points of this 
water-shed usually exceed 400 feet above the river; but one or two 
miles south-east from this moraine the railroad found a line of depres- 
sion only 150 feet above the river, or 537 feet above the sea. On each 
side high hills border this pass, which connects the Contoocook valley 
with that of the north branch of the Piscataquog river. No extensive 
or remarkable deposits of modified drift were seen in a hasty journey 
along the latter valley. 

A third of a mile above West Hopkinton the Contoocook river flows 
between slopes of till 75 feet in height, and so.steep as to suggest that 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 113 


the channel here may have been formed by the erosion of the river. A 
third of a mile from this railroad station, several parallel kames are found 
extending nearly east and west between the highway and the outlet from 
Rolfe’s pond. These are composed of the usual water-worn gravel, with 
pebbles up to one foot in size, and form ridges and mounds 25 or 30 feet 
high and 60 feet above the river. 

In the remaining ten miles of its course the Contoocook is almost con- 
tinuously bordered by extensive low plains, seldom exceeding 30 feet 
above the river, with occasional areas of interval, but no kames were 
seen. On the south side of the river, below West Hopkinton, portions of 
these plains are 50 feet above the river; and on the north side the same 
height is reached by a delta-like deposit where the outlet from Clement 
pond enters the alluvial area. At Contoocookville the alluvium is in- 
terrupted by low areas of till or ledge, that upon the north side being 
quite low and scarcely higher than the plains, which seem at the edge of 
the village to extend across it. Thence eastward low sandy plains, from 
15 to 25 feet above the Contoocook, extend nearly level for eight miles to 
the Merrimack river. Their greatest expanse is in the north-east part of 
Hopkinton, the north-west corner of Concord, and the south edge of 
Webster, where they cover an area three miles long from north to south 
and nearly two miles wide. This at the north consists partly of swampy 
land, slightly depressed, and with no outlet for drainage. Warner and 
Blackwater rivers, which are tributary to the Contoocook in Hopkinton, 
are bordered by considerable alluvial deposits, the former in Warner and 
the latter in Salisbury. 

Three miles above its mouth the Contoocook is enclosed by hills with 
only a narrow alluvial margin. The proper continuity of its plain is here 
along the Concord & Claremont Railroad, with a hill between it and the 
river, east of which the plain is wide, lying principally on the south side 
of the Contoocook river, at a height of 125 feet above the Merrimack. 
Below Contoocookville the river has a height of about 355 feet above the 
sea nearly to Fisherville, where it descends rapidly to its mouth, which is 
249 feet above the sea. 

We will next consider the course of events in the Champlain period, of 


which these deposits of modified drift bear witness. 
VOL. UL 15 


II4 SURFACE GEOLOGY. 


Review and Conclusions. 

The continuousness in height of the plains of the Merrimack valley in 
Concord with those through which the last ten miles of the Contoocook 
flows, has been already noticed (p. 80). A comparison of this with the 
deficient height of the terraces of the Merrimack opposite to and for a 
few miles above the mouth of this river (pp. 78 and 79), leads to the 
conclusion that a large proportion of the modified drift of Concord was 
brought into the Merrimack valley by the Soucook and Contoocook 
rivers. The latter contributed to the plain of East Concord, and alone 
filled the large area between West Concord and Fisherville. 

The extensive plains of the Contoocook, in the north-west part of Con- 
cord and through Hopkinton, occupy two basins of unequal size, which 
we must suppose held lakes at the first retreat of the ice-sheet. These 
were filled, as the melting of the ice continued, by the alluvium of its 
floods. A large share was supplied by the tributaries from the north; 
and the kames near West Hopkinton were formed by a glacial river, 
which descended at the head of the valley. To this point the formation 
of modified drift seems to have proceeded quite in the ordinary way. 

In the east part of Henniker the first outlet from this valley was prob- 
ably to the south-east into the basin of Piscataquog river. The moraine 
and kame which extend along the old line of the New Hampshire Cen- 
tral Railroad, at the south-west side of the alluvial area of the Contoo- 
cook, indicate a considerable period in which the terminal front of the 
rock-bearing glacier remained nearly stationary, succeeded by a period 
of retreat northward, when a large river, laden with sand and gravel, 
descended from the melting ice-fields. At the time of formation of this 
kame a small lake, nearly as deep as to cover its top, lay between the 
front of the glacier and the outlet of its waters to the south. The glacial 
river, entering this deep and quiet lakelet, deposited more quickly than 
usual nearly its whole freight, both of gravel and sand. Somewhat later, 
but while the outlet was still to the south, the kames on the north side 
of the valley south-west from Whittaker pond were formed; and we may 
presume that this date was nearly the same with that of the kames of 
West Hopkinton, which show that the valley of the Contoocook below 
was clear from ice. Not long after this time the glacial barrier between 
these basins disappeared, and drainage took its present course. Whether 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. II5 


the kames at the east side of Henniker village were formed before or 
after this change, cannot perhaps be determined. Their position, trans- 
verse to the Contoocook, shows that they were formed by streams from 
the melting glacier on the north in the valleys of Amy and Warner 
brooks, while the rapid retreat of the ice to the west and south-west ap- 
pears to have been delayed by the high hills which closely border the 
river. It is not improbable that, when these waters first flowed towards 
the north-east down the Contoocook valley, a barrier of till near West 
Hopkinton, afterwards eroded by the river, held back a shallow lake 
which extended to the kames last mentioned. The deposition of the 
low alluvium of this area was going slowly forward during all the time 
occupied by this history. 

The melting of the vast ice-sheet over New England proceeded from 
the coast to the north-west and north, so that lakes were temporarily 
formed in valleys which drain northward. The avenues by which the 
waters escaped from the upper portion of the Contoocook basin, or 
that part above Long fall in the west part of Henniker, appear to have 
been three in number, as follows: Southward, over the water-shed at 
the head of the valley in Rindge; towards the south-east, through Green- 
field; and northward, along the course of the river. The length of this 
area is nearly thirty miles; and the outlet in Greenfield is about equally 
distant from its south and north ends. 

The conspicuous kames, which extend five miles along the Vermont 
& Massachusetts Railroad between South Ashburnham Junction and 
Westminster, show that a large area of the ice-fields on the north-west 
poured their waters along this course. These kames are less than 200 
feet below the plateau in Rindge, twelve miles distant, which forms the 
water-shed at the head of the Contoocook valley. Although the present 
drainage of the south part of Rindge and of Winchendon is into Miller’s 
river and the Connecticut, there is no considerable depression; and the 
separation between this basin and the head of the Nashua valley, in 
which these kames are found, is not so high as the water-shed in Rindge. 
This area has not been explored; but the deposits of modified drift in 
Rindge make it probable that the melting of the ice-sheet, while its out- 
let continued in this direction, proceeded beyond this divide, including a 
portion of the Contoocook basin. 


116 SURFACE GEOLOGY. 


The principal outlet from the part of this basin in Hillsborough county 
appears to have been through Greenfield south-easterly to Souhegan 
river. South from this pass the east border of the Contoocook valley 
is formed by Pack Monadnock, Temple, Kidder, and Barrett mountains, 
which extend in a continuous range through the west portions of Temple 
and New Ipswich. Northward this valley has a high eastern water-shed 
two to four miles from the river, with no deep depression till we reach 
the pass through which we have supposed a former outflow towards Pis- 
cataquog river. The culminating points of this water-shed are at its 
south and north ends, in Crotched mountain and Craney hill. 

When the melting of the ice-sheet had advanced so far as to open an 
avenue from this valley through Greenfield, we may suppose that large 
streams descended from the glacier to this point, by which the kames on 
the east side of the railroad south of the village, those between Hogback 
and Pollard ponds and along the road northward between Greenfield and 
Bennington, and those at Bennington station and for a mile north-west on 
both sides of Contoocook river, were in succession deposited. The fine 
alluvium of these streams was at first spread out in the level plain east of 
Cragin pond, while ice still remained over the area now occupied by this 
pond. A small lake was afterward formed by the melting of the ice on 
the north-west side of the pass. This lake received the finer drift brought 
down by the glacial rivers, producing the alluvial plain west and north- 
west from Greenfield. 

A channel appears next to have been formed farther to the north-west, 
skirting the hills upon the east side of the valley and walled on the west 
by ice. This became filled by the nearly level-topped and terrace-like 
gravel and sand seen on the east side of the Manchester & Keene Rail- 
road south from Bennington station, which seem to belong to the same 
date with the kames at this station and about Whittemore pond. The 
kames were probably formed in ice-channels which were narrow and 
somewhat higher than the former, with so rapid a descent that only 
coarse gravel was deposited in them by the summer floods, the sand be- 
ing carried onward to the quiet waters of the channel below, which was 
an arm of the lake. With the full melting of the ice, however, such of the 
kames as had been formed over the middle of the valley sank to its bot- 
tom, and are found at a lower level than the principal deposits of fine 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 117 


gravel and sand, which remain nearly at their original height upon the 
hillside. 

The kames which we find south-west from Bennington, and a large 
portion of those north of Whittemore pond, are principally composed cf 
sand and fine gravel. They were probably deposited at the mouth of 
the glacial streams where these entered the lake, nearly all the modified 
drift which was brought from the melting ice being thus accumulated in 
mounds, ridges, and terrace-like banks. The want of continuity in these 
deposits appears to be due to the irregular rate of melting and to the 
varying slopes assumed by the terminal front of the ice-sheet, the latter 
being determined by this rate and by the contour of the valley. 

The lack of stratified drift in the valley west from the Greenfield plain 
seems to show that the ice over this area, while it still confined the little 
lake on the east, had been melted nearly to this level, sending its alluvium 
to form this plain; and that the remainder disappeared from the valley 
without sufficient currents to form alluvial deposits. All the material 
which it still held was dropped as unstratified till, unless we except rare 
instances of kames like the isolated banks of sand seen on the hillside 
east of the river near the north line of Peterborough. 

The first deposit belonging to this period that we meet in going up the 
valley is the high level-topped sand north-west from North Peterborough. 
This and other terrace-like deposits extending to Peterborough appear to 
be of similar origin with those already noticed south of Bennington sta- 
tion. Kames of the common type, composed of coarse gravel and sand, 
occur one and two miles farther up the valley; and they are increased in 
amount as we approach the line between Peterborough and Jaffrey, ap- 
pearing to have come principally from Sharon on the south-east. We 
may suppose that these, as in Bennington, were deposited at the same 
date with the sand which partly filled the opening channel below. This 
was a branch of the lake, and the sand fell in irregular and thin deposits 
with stratification conforming to the sloping sides of the valley. The 
occasional boulders which we find embedded in the alluvial deposits of 
this lake appear to have been dropped by floating masses of ice broken 
from the glacier which bordered its shores. 

Going down the valley we find evidence that the glacial melting ad- 
vanced beyond Hillsborough Bridge, while its outlet continued to be 


118 SURFACE GEOLOGY. 


through Greenfield. The last blockade of the ice-shect in its retreat to 
the north may have been at Long fall, in the west part of Henniker, 
where the high hills leave a narrower space than usual for the passage 
of the river. The large proportion of sand in the kames of the north 
part of Bennington is what we should expect, if their deposition was at 
the mouth of glacial rivers where they entered the lake. The most im- 
portant testimony, however, is given by high deposits of sand and fine 
gravel, like that on Hedgehog hill in Deering. The widened lake now 
filled the whole valley; and these deltas, brought in by glacial rivers or 
tributary streams, mark its height and shore line, and enable us to gauge 
the floods which were supplied from the melting ice. 

The earliest of these lake-shore deposits are the plain of Greenfield 
and that of Hancock village. Both of these have the same height 
with the outlet, over which there as yet flowed only a shallow stream. 
When the lake had advanced north to Clinton village in Antrim, the 
depth of its outflow was probably 20 feet, as shown by a level-topped 
ridge of sand and fine gravel exposed on the north side of Great brook 
and the road, a quarter of a mile east from Hastings’s mill. This deposit 
extends a quarter of a mile to the north, and also occurs south of this 
stream, by which it was formed about at the level of the lake. High 
sand was also found three miles farther north, on the water-shed between 
Cochran brook and North Branch, at the south-west side of Riley moun- 
tain. This is two and a half miles due west from that on Hedgehog 
hill. Both these deposits are level-topped deltas of glacial streams that 
descended to the lake from the north, having the place of their inlet de- 
termined by the gap of the adjacent hills. Their heights are the same, 
and show that at the time of their formation 50 feet of water poured 
over the outlet in Greenfield. Somewhat later, when the lake reached 
its greatest extent and received its largest tribute from the more rapidly 
melting ice-sheet, the depth of water discharged was 80 feet, as shown 
by a delta-terrace half a mile south-west from Hillsborough Centre, and 
by plains which occur at the same height north-east of Hillsborough Up- 
per Village. All these deposits are level-topped, or nearly so; and their 
position is generally on steep hillsides, with no barrier, if the drainage 
had been the same as now, to prevent their being carried forward to the 
bottom of the valley. Other deltas similar to these might probably be 
found by a more thorough exploration of the ancient lake shore. 


MODIFIED DRIFT ALONG CONTOOCOOK RIVER. 


119 


Heights of the Outlet and Deltas of the Lake which filled the Contoocook 
Valley through Hillsborough County in the Champlain Period.* 


Cutlet of lake, 14 miles south-east from 
Greenfield, being the lowest point of 
water-shed between Contoocook and 
Souhegan rivers (2 feet lower than 
the railroad summit), $63. 

Cragin pond, 830. 

Greenfield station, 834. 

Pollard pond, 810. 

Delta cut by the railroad 4 mile north- 
west from Greenfield station, nearly 
the same in height with the fair- 
ground, 864. 


Delta at Hancock village, $62. 

Delta at Clinton village, Antrim, 883. 

Delta south-west of Riley mt., Antrim, 
912-915. 

Delta on Hedgehog hill, Deering, 905-920. 

Delta 4 mile south-west from Hillsborough 
Centre, 940. 

Delta north-east of Hillsborough Upper 
Village, 942. 

Kames at church and cemetery between 
Hillsborough Upper and Lower Vil- 
lages, 930. 


The depth of this lake was from 200 to 350 feet, as will be seen from the following: 


Heights along Contoocook [iver. 


Foot and head of fall at North Peter- 
borough, 714-724. 


Head of Long fall, near county line, 546. 

At Hillsborough Bridge, foot of falls, 564; 
lower dam, 576; upper dam, 591. Same at Peterborough, 727-734. 

At Bennington, foot of falls, 606; Paper- River at county line, about 875. 

mill pond, 635; Kimball’s dam, 645; 

King’s dam, 655; Whitney’s dam, 


668; Powder-mill dam, 676. 


At length the melting of the ice along the lower part of the valley at 
the north-east met the already open portion which extended through 
Hillsborough county, and the drainage of the basin took its present 


* The heights from Greenfield to Paper Mill Village inclusive, given in Vol. 1, p. 268, are too low, requiring 
the addition of 36 feet to agree with recent surveys of R. S. Howe for the Hillsborough*& Peterborough Railroad, 
and with those of Hon. J. A. Weston for the Manchester & Keene and Monadnock railroads, published in Vol. 
I, p. 271. The heights given above are derived from the profiles of these railroads, or from special survey. They 
are stated in feet above the sea. 


Our levelling to determine the height of deltas gave opportunity to note also the water-power of two tributaries 
of the Contoocook. 

Heights along Great Brook, Antrim. Mouth of brook, 600; Thompson’s mill-pond, 624; Goodell’s saw-mill 
pond, 641; Goodell’s next pond, 657; Poor’s saw-mill pond, 672; Goodell’s cutlery-shop pond, 703; Kelsey & 
Co.’s pond, 717; Baptist and Methodist churches, South Antrim, 719; road at foot of sand delta, Clinton vil- 
lage, 853; hay-scales platform at Clinton village, E. Z. Hastings’s house, and his mill-pond, each, 914; Gregg’s 
pond, according to an old survey, 1064. 

Heights along North Branch in Hillsborough and Antrim, Mouth of Branch, 592 ; mouth of Beard’s brook, 
near foundry, 600; Foundry mill-pond, 618; Young’s (formerly Dickey’s) mill-pond, 702; Tannery mill-pond, 
728; still water, 4% mile above Hillsborough Lower Village, 750. (The following heights of this stream in Antrim 
are from survey by G. C. Patten, in 1874.) Foot of rapids, }4 mile east of W. Curtis’s, 755; Curtis’s dam, 852; 
foot of falls at North Branch village, 862; Parkhurst’s dam, 902; at Boutwell’s bridge, 1 mile above this village 
985 ; proposed reservoir of 100 acres above do., 1025; J. Loveren’s dam, 1077; foot of falls below do., 1024. : 


120 SURFACE GEOLOGY. 


course to the north. The erosion of the high deposits in the south part 
of Peterborough and the tribute of streams near the source of the 
river now supplied the low alluvium which extends for two miles below 
North Peterborough. The kames in Bennington probably also suffered 
considerable erosion, which, with the important streams on the west, fur- 
nished the similar low alluvial deposits of Antrim, Deering, and Hills- 


borough. 


MopiFiep Drirt oF WINNIPISEOGEE AND SQuAM LAKEs. 


The beauty of Winnipiseogee lake is due to its multitude of irregularly 
grouped islands, to the three long bays or arms into which its north end 
is divided, and to the winding outlines of its shores. The water-shed 
which bounds its basin reaches no point more than seven miles distant 
from the lake.* It passes over Belknap, Cropple Crown, and Ossipee 
mountains, and Red hill, which rise from 1,500 to 1,900 feet above the 
lake; but its other highest points are hills of half this height or less, 
which descend steeply to the west and south shores but have more gen- 
tle slopes on the east and north. Somewhat farther distant, at the north, 
the view from Winnipiseogee embraces Chocorua, Paugus, Passaconaway, 
Whiteface, and Sandwich Dome, which form the southern front of the 
White Mountains; and from many parts Mt. Washington is also visible. 
To know this scenery fully, the lake must also be seen from the moun- 
tains and hills by which it is environed. The most magnificent of these 
views is that from Red hill, which overlooks both Winnipiseogee and 
Squam lakes. 

The depth of Winnipiseogee lake was measured by the Lake Company 
at the same time that the survey of its area was made. The deepest 
place found was a short distance off the east shore of Rattlesnake island, 
opposite to its southern and lowest peak. The depth at this spot was 
slightly more than 200 feet. Between Rattlesnake and Diamond islands 
it was 190 feet; in Alton bay, opposite Fort and Gerrish points, 100 
feet, and at three fourths of a mile from its south end, 80 feet; in the 
broad portions of the lake, between Rattlesnake and Cow islands, from 
100 to 150 feet; and between Cow island and Center Harbor, from 50 to 


* The topographic features of this district, and the areas of Winnipiseogee lake, its islands, and its hydrographic 
basin, are stated in Vol. I, pp. 203-205, 300, and 306-308. 


MODIFIED DRIFT OF THE LAKE DISTRICT. I2I 


75 feet. The pre-glacial outlets from this basin were along the present 
course of the Winnipiseogee river and south-east from Alton bay towards 
Cochecho river. Both of these old outlets are partly filled with till or 
modified drift; but it is certain that if these materials were wholly re- 
moved a large portion of the lake would remain, bordered by rock on all 
sides. 

The lowest points in the water-shed around Winnipiseogee lake, with 
their heights in feet above the lake, are the following: Summit on railroad 
between Meredith Village and Pemigewasset valley at Ashland, 166, ten 
feet below the natural surface; at two and a half miles north from Mere- 
dith Village, about 140, and at same distance north from Center Harbor, 
about 100, these points being the lowest between this and Squam lake; 
the “Varney pass,” between Moultonborough and the Bear Camp valley, 
about 150; summit on railroad between Wolfeborough and Salmon Falls 
valley, 164; between Smith’s pond and Cook’s pond, about 200; summit 
on railroad between Alton Bay and Cochecho valley, 72; and near Lily 
pond in Gilford, between the lake and Long bay, about 75 feet. The two 
last of these places show by their modified drift that they were formerly 
outlets of the lake. 

These lake basins lie upon the south side of the White Mountains, from 
which source we might expect a greater depth of ice to move southward 
and cover this area near the close of the glacial period than would at that 
time remain in other parts of the state to the east and west. The ice- 
sheet probably lay over Squam and Winnipiseogee lakes in a broad moun- 
tain-like ridge till after it was almost wholly melted away over the low- 
lands of York county, Maine, in the basin of Ossipee lake, and for some 
distance along the Bear Camp valley. The ice-current was thus changed 
in direction on this side, and the last striz marked on the ledges differ 
much from the prevailing course of about S. 40° E., being deflected 
towards the east or even to the north of east. This is shown by the fol- 
lowing observations, all of which are reduced to the true meridian.* 


* The magnetic needle has a declination of 12° to the west. (See map, vol. i, p. 154.) 


VOL. III. 16 


122 


SURFACE GEOLOGY. 


Courses of Stria about Winntpiseogee and Squam Lakes. 


On the North-East and East Side. 


Nearly all of these are deflected easterly from the prevailing course of the ice-sheet; 
probably because of its earlier melting in the basin of Ossipee lake. 


In Flolderness. 
Road over Squam mountain, S. 60° E. 
In Sandwich. 
At west line on road to Ashland, S. 80° E. 
Near north-east corner of Squam lake, N. 
85° E. 
At north foot of Red hill, N. 80° E. 
In Moultonborough. 
Near south-east town line, S. 55° E. 
In Tuftonborough. 
Near Melvin Village, S. 25° E. 
At Tuftonborough Corner, N. 70° E. 
Two miles south of last, N. 80° E. 


One half mile farther south, E. 
(The two last in Tuftonborough are on the 
hills west of Lower Beech pond.) 
Ln Wolfeborough. 
West side of Trask hill, S. 85° E. 
Summit of Trask hill, S. 50° E. 
One mile north-east from Wolfeborough 
Centre, S. 40° E., and E. 
Porcupine ledge, S. 60° E. 
Ln Brookfield. 
North corner of town, S. 55° E. 
Two miles south of last, S. 70° E. 
North side of Tumble-down Dick, S.75°E. 


On the West and South-West Side. 


These show the general direction of the ice-current, coinciding nearly with the longer 


axis of Winnipiseogee lake. 


Ashland village, S. 40° E. 
Center Harbor, commonly S. 40° E. 
In New Hampton. 
Above clay-bed, two miles south-east from 
Ashland, S. 35° E. 
Harper’s hill, S. 50° E. 
New Hampton centre, S. 40° E. 
New Hampton village, S. 50° E. 
In Meredith, 
Hill north-west from Meredith Village, S. 
40° E. 


Meredith Centre, S. 25° E. 
Highest hill, Meredith Neck, S. 40° E. 
Ln Gilford. 
North part, near lake, S. 35° E. 
Hill north-east from Lake Village, S. 35° E. 
North-east part, near lake, S. 4o° E. 
In Alton. 
Ridge west of Alton Bay, S. 40° E. 
Town line, east of Alton Bay, S 40° E. 


In New Durham, commonly S. 40° E. 


The departure of the ice-sheet along the Merrimack and Pemigewasset 
valley appears also to have proceeded somewhat more rapidly than upon 
the higher land on its east side, so that over Winnipiseogee and Squam 
lakes the drainage from the melting ice was outward both to the east and 
west. 


MODIFIED DRIFT OF THE LAKE DISTRICT. 123 


The noticeable feature in the surface geology of these lakes is the ab- 
sence of modified drift. Their shores are chiefly of coarse glacial drift 
or till, with occasional ledges. The neighboring basin of Ossipee lake, 
on the contrary, is characterized by very extensive and probably thick 
deposits of modified drift, presenting a remarkable contrast. These de- 
posits are also abundant in the Pemigewasset valley on the west. Their 
conspicuous absence from these intervening basins needs to be accounted 
for, and this seems to be due to different rates of progress in the depart- 
ure of the ice. The later continuance of the ice-sheet over these lakes 
turned all the drainage from the south side of the White Mountains into 
the Ossipee basin and Pemigewasset valley, and even caused the modi- 
fied drift, which was contained in this part of the ice, to be mostly car- 
ried away. Our explanation of the remarkable deflection of striz on the 
east border of these lakes is thus attested also by the modified drift, as 
by a separate and independent witness. 

In describing the modified drift of this area, we will proceed from the 
mouth of Winnipiseogee river to the Wiers, and thence northward, in- 
cluding Squam lake, and passing around Winnipiseogee. The extent of 
these deposits is shown on the general geological map in the atlas. The 
interesting beds of clay and rarely of sand, overlaid by till, which occur 
at numerous places about these lakes, constitute a peculiar class of modi- 
fied drift found nowhere else in the state. The localities of ordinary 
modified drift will be first described, and afterwards the instances of clay 
or sand overlaid by till. An explanation of the probable mode of forma- 
tion of these different deposits will then be stated. 

The mouth of Winnipiseogee river at Franklin is 269 feet above the 
sea. Its fall in the last two miles of its course is 146 feet, and its whole 
descent from the lake is 244 feet. (See p. 103.) The modified drift of 
the Merrimack valley is well shown on both sides at Franklin, its highest 
terrace being 150 to 175 feet above the river; but the Winnipiseogee, for 
the last mile and a half before entering this valley, is bordered only by 
till or ledge. The first area of modified drift that we find on this stream 
lies between Cross’s mill-pond and Tilton, extending about a mile along 
the river and as far to the south, where it lies principally on the west side 
of the railroad. This deposit of sand and gravel has a height 30 to so 


feet above the river, slightly exceeding the upper terraces of the Merri- 
mack at Franklin. 


124 SURFACE GEOLOGY. 


At Tilton, and for a mile above, the river has no modified drift. In the 
upper part of this distance the very steep slopes of till between which it 
flows indicate that a channel 50 feet deep may have been excavated in 
this material by the river. We next come to the largest area of modified 
drift found on this river. This extends nearly two miles along its north- 
west side, bordering Little bay nearly to East Tilton. A large part of 
this deposit was brought by the tributary which comes from Sanbornton 
Square. An interesting kame, forming a ridge of very coarse water- 
worn gravel, 30 to 40 feet high and a quarter of a mile long, lies on the 
west side of this stream at the margin of the modified drift. From its 
east side a plain of coarse gravel, 30 to 50 feet above the river, extends 
a third of a mile eastward, beyond which to Little bay the height is less, 
being 10 to 20 feet above the bay, and the material is finer gravel or sand. 
The edge of the high plain of coarse gravel is cut by the railroad; and 
the section shows the upper fifteen feet to consist of levelly stratified 
gravel, with its largest pebbles one foot or more in diameter, underlaid 
by several feet of sand, which is partly horizontal and partly oblique in 
stratification. The gravel is interstratified with the upper portion of the 
sand. This fine alluvium was probably brought by the large stream 
which comes in from Belmont, joining the Winnipiseogee from its oppo- 
site side at a short distance farther east. This tributary is bordered on 
the north by a wide sand plain, about 30 feet in height, which extends 
nearly two miles above its mouth. This was deposited in the Champlain 
period, since which time the stream has excavated a considerable portion 
of its plain, forming a wide meadow along its last mile. Previous to any 
erosion, this plain appears to have been continuous across the present 
channel of Winnipiseogee river; and we thus find a portion of it under- 
lying the coarse gravel which came from the opposite direction, being 
supplied abundantly at a little later date as the melting of the ice-sheet 
advanced to the north-west. 

The successive expansions of the Winnipiseogee river are called bays. 
In ascending the river they are met in the following order: 


Height 


Approximate area. above sea. 
Little bay, ‘ F : é 4 ‘4 ‘ . -5 square miles. 473 feet. 
Sanbornton bay, . 7 ‘ Fi 7 ‘ 1.0 ee 4go ‘“* 


Great bay (Winnisquam lake), 3 ‘ 5 : 5.0 “ 490 ‘“ 


ie 


MODIFIED DRIFT OF THE LAKE DISTRICT. 125 


Round bay, . é 5 .5 square miles. sor feet. 


Long bay (of same height with Winnipiseogee lake), 1.9 ef 513“ 


The east and north shores of Little bay and the south and west shores 
of Sanbornton bay north to Mohawk point, with the river between them, 
are destitute of modified drift; but it is found on the east shore of San- 
bornton bay, extending along the railroad from Ephraim’s cove to Winni- 
squam station at the bridge between this and Great bay. This deposit 
consists principally of gravel, much of it containing pebbles a foot in 
diameter, and it has a height of 10 or 20 feet above the bay. Its origin, 
and the cause of its accumulation along this margin of the bay, appear to 
be shown by the kame of coarse gravel, from 10 to 15 feet in height, 
which forms Mohawk point, and is connected with the east shore by a 
low bar of gravel and sand. On the west side of the bay, opposite Mo- 
hawk point and only a short distance from it, a higher bank of the same 
gravel occurs. These kames appear to have been formed in the channel 
of a glacial river, which came down from the north-west at a time when 
the ice covered the greater part of this bay. It had been melted away 
only along the east shore, which therefore received from this and other 
streams a border of modified drift. The sand plain, about 20 feet in 
height, which extends along the west side of the bay for a mile north 
from these kames, was brought down from the same direction after the 
ice had retreated from this area. 

The next deposit of modified drift that we find is the sand plain on 
which the south part of Laconia village is built. This is about one third 
of a mile square, and from 15 to 20 feet above Great bay. One half mile 
farther north a small deposit of gravel and sand is crossed by the railroad 
on the south-east side of Round bay. No modified drift was seen at 
Lake Village, and the hills rise steeply on each side. In digging for foun- 
dation for the dam and mills here, sand is said to have been found under 
sixteen feet of till, This sheltered situation has probably preserved a 
remnant of alluvium, which was deposited before the glacial period or dur- 
ing some temporary withdrawal of the ice. A half mile north-east from 
Lake Village we come to a sand plain, from 10 to 20 feet in height, which 
extends a half mile to the north and east. Before the ice-sheet was melt- 
ed away at the Wiers, the waters from the lake had their outlet at this 
place, passing over the low water-shed on the east near Lily pond. On 


126 SURFACE GEOLOGY. 


the north-west side of Long bay a small brook has brought down a deposit 
of sand and gravel which is crossed by the railroad. 

The mouth of Lake Winnipiseogee is a narrow channel called the Wiers, 
because of dams made here by the Indians for taking fish. No modi- 
fied drift of the ordinary kind occurs near this outlet or along the shore 
of the lake north-west to Meredith Village. A small kame-like deposit of 
coarse gravel and sand, 40 feet above the lake, occurs a short distance 
north-east from Meredith depot; and alluvial sand about 25 feet in height 
borders the brook which flows into the head of this bay and extends half 
a mile eastward along the lake shore. Wukawan lake and Long pond, 
which lie on the north-east side of the railroad above Meredith, are the 
same in height, being 36 feet above high water in Winnipiseogee lake. 
They are separated by a swampy area, but with this exception are sur- 
rounded on all sides by till or ledge. Another Long pond, one half mile 
east of Center Harbor and about 10 feet above the lake, has a small area 
of alluvial sand and clay at its outlet. 

The shores of Squam and Little Squam lakes, like those of Winnipi- 
seogee, are: almost wholly composed of till or ledge. The only modified 
drift seen in a journey by the roads along the east and south sides of 
Squam lake was at a point a mile and a half south-east from White Oak 
pond. This consists of kame-like gravel and sand, irregularly stratified, 
with occasional large boulders on the surface. A well defined kame, 15 
to 25 feet high, extends a fourth of a mile west from the bridge between 
these lakes along the north shore of Little Squam. This ridge contains 
frequent angular boulders up to three or four feet in diameter. Squam 
river above Ashland is bordered by low alluvium a few hundred feet 
wide. Its total descent is 110 feet, nearly all of which is utilized for 
water-power. 

At the head of Moultonborough bay we find swampy land along its 
east shore for a mile, and farther east an extensive deposit of sand, un- 
dulating and partly covered with pines, reaching a mile from the lake, 
with its highest portions 40 feet above it. The next modified drift is 
four miles to the south-east at Melvin village. Melvin river here brought 
down in the Champlain period a small plain of gravel and sand, which 
since that time has been partly excavated by the stream, and partly un- 
dermined and carried away by the lake, so that it now forms a terrace 20 


MODIFIED DRIFT OF THE LAKE DISTRICT. 127 


feet high. Another tributary to the lake a mile farther south-east is bor- 
dered by terraces of similar height near its mouth. On the north-east 
side of Twenty-mile bay, two miles south from Melvin village, a bold 
shore of coarse till, with many large boulders, is bordered by an old 
beach, about 300 feet long and 100 wide, which slopes from the water's 
edge to ten or twelve feet above high water. It is composed of fine 
stratified sand, which is clayey below a foot or two of the surface. No 
tributary occurs here, but a small stream at an eighth of a mile south- 
east has brought down considerable alluvial sand, none of which, how- 
ever, lies more than five feet above high water. 

Kames. Half a mile farther south we find a kame extending two 
thirds of a mile from north-west to south-east along the top of a hill 
about 100 feet above the lake. It does not form a definite ridge, and could 
hardly be distinguished from the till by its contour. Its materials are 
coarse and fine gravel and sand interstratified. Boulders are enclosed in 
many portions, but a well at Charles G. Edgerly’s, 30 feet deep, encoun- 
tered no boulders, being all the way through sand or fine gravel. Nine- 
teen-mile bay and brook are a half mile farther south. Here the road 
passes over the alluvium brought down by this brook, which, like that at 
the head of Twenty-mile bay, is only three or four feet above the lake. 
Nineteen-mile brook is bordered by considerable widths of low alluvium 
for two miles above its mouth, to where it is crossed by the road a mile 
and a half south from Mackerel Corner. From the brook to this village, 
and for a half mile farther north, kame-like deposits of limited amount are 
seen here and there at heights of 100 to 200 feet above the lake. East 
from this road interesting kames extend more than a mile along the 
north-east side of Nineteen-mile brook. These cover a width of a fourth 
of a mile, consisting of successive small plains from half an acre to two 
or three acres in extent, usually surrounded by hollows, and rising one 
after another from 30 or §0 to 100 feet above the stream, or fully 150 feet 
above the lake. These small level-topped deposits consist of sand and 
water-worn gravel, with the largest pebbles about one foot in diameter, 
Boulders are occasionally but not frequently enclosed. These kames 
begin about two miles south-east from that described between Twenty- 
mile and Nineteen-mile bays. These and the similar deposits which oc- 
casionally appear about Mackerel Corner probably had a common date 


128 SURFACE GEOLOGY, 


and cause. Advancing to the south-east we leave the modified drift, but 
cross a water-shed which is probably lower than the highest of these 
kames, and thence follow Hersey brook to Smith’s pond. A sandy plain, 
about 50 feet above the pond or 75 feet above the lake, is found on the 
west side of this brook near its mouth, covering about half a mile square. 
The shores of this pond, like those of the lake, are almost entirely till or 
ledge. 

Upper Beech pond, covering perhaps 150 acres and about 300 feet 
above Lake Winnipiseogee, is situated a mile and a half north-east from 
the kames last described. Its outlet is to Ossipee lake by Beech river, 
but only a very slight barrier at its south-west side prevents its flowing 
to Winnipiseogee lake by Nineteen-mile brook. This barrier consists of 
a kame, which in its north-west portion is a nearly 
level plain three or four acres in extent, but for 
several hundred feet south-east from this it is nar- 
rowed to a mere ridge. The gravel of the small 
plain is but slightly water-worn, the rock fragments 


itis, 2 Oeten Ewe being from a foot to a foot and a half in size. The 

UpreR BEECH Ponp, ridge consists of sand or finer gravel, in which 

WOLFEBOROUGH. fragments larger than six inches are uncommon. 

Seale; Tinch—t mile: THis whole deposit is bounded by steep slopes both 
against the pond and on the opposite side. The height of the plain is 
20 to 30 feet above the pond; that of the ridge declines to only ten feet, 
and at its east end to only three feet above the pond, while its south-west 
slope falls abruptly to 20 or 30 feet below it. Large springs fed from the 
pond issue at the bottom of this bank. Except at this point and its out- 
let, this pond is surrounded by high hills; and no other kame-like deposits 
occur on its shores or in the steeply sloping valley that descends towards 
the south-west from this barrier. 

The shores of the lake through Wolfeborough have no modified drift 
worthy of note. It is next met with in Alton, about a mile east from 
Fort point and the mouth of Alton bay. Proceeding eastward from the 
mouth of the bay, we soon come to a hill more than 200 feet high, and at 
its east side find an area of considerable width, which is only 50 to 60 
feet above the lake, and extends about two miles from north to south 


between the lake and the bay at Gerrish point. Where this area is 


MODIFIED DRIFT OF THE LAKE DISTRICT. 129 


crossed by the road to Fort point, it is a level, sandy plain, but south- 
ward it is partly occupied by a similar plain and partly by kames, which 
form mounds and ridges, extending from north to south, with the inter- 
vening hollows 20 to 30 feet deep. The material of the kames is water- 
worn gravel, containing pebbles up to one or two feet, and often enclosing 
boulders of all sizes up to six or eight feet in diameter. 

On the west shore of Alton bay, south-west from Gerrish point, we 
find kames and level-topped mounds of interstratified sand and gravel, 
with occasional large boulders enclosed or on the surface. These rise 
about 50 feet above the lake, and border its shore for nearly a half mile, 
extending southward from the mouth of the principal valley or opening 
among the hills on its west side. With these exceptions, till and ledge 
form the shores of this bay till we come to its end at the south extremity 
of the lake. 

From Alton Bay station a continuous area of modified drift, varying 
from one fourth of a mile to nearly two miles in width, extends towards 
the south-east along Merrymeeting river and across the low water-shed 
only 72 feet above the lake, which separates this basin from the head of 
the Cochecho valley. A kame, forming a well defined ridge 40 to 60 feet 
high, extends nearly a mile southward from the lake. It lies for the first 
third of a mile on the west side of the railroad, by which it is then crossed 
twice, thence continuing to the south close upon the west side of the 
river. It is mainly composed of coarse water-worn gravel, which con- 
tains rounded boulders up to two or three feet in diameter. It also con- 
tains occasional angular boulders of larger size, and in some.portions the 
ridge is made up almost wholly of such angular blocks one to four feet in 
diameter. Deposits of fine gravel and sand reach an equal height along 
this distance on the east side of the river. 

Alton village is situated about 60 feet above the lake on a level plain, 
the north part of which is coarse gravel full of pebbles three inches to 
one foot in diameter, while its south portion is finer gravel or sand. To 
the south-east the alluvium is nearly two miles wide, and consists of plains 
of sand or fine gravel, and low, marshy meadows. The former do not ex- 
ceed 60 to 70 feet above the lake, or about 30 to 40 above Merrymeeting 
river. No kames were seen between Alton and New Durham station; 


but a short distance from this station a kame 25 feet in height was seen 
VOL. Il. 17 


130 SURFACE GEOLOGY. 


on the west side of the railroad. The wide alluvial area here forms a 
water-shed; and half a mile farther south-east we come to a considera- 
ble stream, which is one of the principal sources of Cochecho river. The 
modified drift continues about a half mile farther, consisting of very coarse 
irregular kames on the west side of the stream, while on the east side is a 
plain of fine gravel or sand about 30 feet in height. The next four miles 
of this valley, extending nearly to Farmington, has a rapid descent, and 
is nearly destitute of modified drift. 

North-west from West Alton frequent kame-like deposits are found 
along the road for three fourths of a mile. These consist mainly of sand 
and gravel interstratified, with numerous boulders enclosed or on the 
surface, and are disposed in nearly level-topped, irregular terraces, with 
gently-sloping escarpments. Similar kame-like terraces occur in Gilford 
at two and three miles farther to the north-west. These all lie upon hill- 
sides of till or ledge, which border the lake, at a height of about 75 feet 
above it. Alluvial sand only 5 to 10 feet above the lake has been depos- 
ited by a small brook near the north-east corner of Gilford, and also by 
a stream which enters the lake below the last mentioned terrace, coming 
from the valley east of the Belknap range. 

Two miles farther west we come to a large alluvial area, which borders 
Gunstock river and Meadow brook, extending nearly a mile in width from 
the lake to Lily pond, thus forming the water-shed probably not more 
than 75 feet in height between the lake and Long bay. This modified 
drift is ‘gravel, sand, or fine silt, with a quite regular surface which slopes 
gently to the lake. A considerable tract of it is interval, being over- 
flowed by the freshets of Gunstock river. A continuous area of modi- 
fied drift appears to extend north from Lily pond to the lake at a point 
about one mile east of the Wiers. We here find, south from the bridge 
to Davis island, very well marked kames, which form north and south 
ridges 50 feet above the lake. They consist of water-worn gravel, with 
pebbles up to one foot in diameter, and enclose occasional boulders. A 
terrace of similar materials borders the hills on their west sides. 

All the ordinary modified drift which we found in our exploration of 
‘these lakes has now been mentioned. A more remarkable class of 
deposits, which has not been met with in other parts of the state, remains 
to be described. 


MODIFIED DRIFT OF THE LAKE DISTRICT. 131 


Modified Drift overlaid by Till. 


Numerous beds of clay, nearly horizontal in stratification, but overlaid 
and underlaid by coarse unstratified glacial drift or till, are found on hill- 
sides up to heights 200 or 300 feet above Winnipiseogee lake. Similar 
beds of sand appear on hills east of Alton bay. In describing these de- 
posits, we will begin at the Wiers, and proceed around the lake in the 
same order as before. 

The first of these clay beds overlaid by till is beside the railroad, a 
short distance north-west from Wiers station, where it is worked by A. 
Doe & Son for brick-making. This is blue clay, finely laminated and 
nearly horizontal, dipping perhaps 5° to the south-east. At one place 
where the excavation has reached the bottom of the clay, it is underlaid 


Winnipiseogee R.R.  Brick-yard, Till on the surface. A. Doe’s house. 
lake. A. Doe & Son. Clay. 


N.E. 2 Ss. W. 
= ay i . , 500 feet 

POTS Towne oo on re re nee tes we eee eces ene 500 fee 

Fig. 28.-SECTION NEAR WIERS. Distance, } mile; vertical scale, BEB: 


1 inch=400 feet. 


by four feet or more of quicksand. This is at a height of about 25 feet 
above the lake. The thickness of the clay is fully thirty feet, and it is 
exposed by an excavation about 100 feet square. The clay is directly 
overlaid by two to six feet of coarse till, which contains angular boulders 
up to six feet in diameter. This is upon a hillside which rises 100 feet 
higher, and appears on the surface to be wholly composed of till; but 
much of this is probably underlaid by a stratum of clay at no great depth. 
This clay comes to the surface at A. Doe’s house, about 150 feet above 
the lake, where a well 27 feet deep encountered no other material. The 
well filled with water from thin, sandy layers; but most of this clay did 
not show its lines of stratification plainly, and was inclined to break 
with a conchoidal fracture into small pieces. At both places the clay is 
free from stones or gravel, except that small boulders, usually less than a 
foot in diameter, are occasionally found embedded in it. 

In New Hampton, two miles south-east from Ashland, a large deposit 
of clay similar to that at the Wiers occurs on land of Oren Plaisted, lying 
on the east slope of a high hill. The drainage is into the Pemigewasset 


132 SURFACE GEOLOGY. 


river. The height of this clay is, by estimate, 350 feet above the river 
and nearly 250 feet above its highest terraces, or about 800 feet above 
the sea. A well at Mr. Plaisted’s house showed 15 feet of till underlaid 
by 18 feet of clay. A few rods farther north, at nearly the same height, 
the clay is covered by only one or two feet of till. About fifteen rods 
farther north-west, on the steep hillside and some 30 feet higher than 
the foregoing, a small excavation for brick-making shows a bed of clay 
ten feet thick, and probably extending deeper, overlaid by two feet of till. 
This clay is free from pebbles, but occasionally shows layers of sand half 
an inch thick. Its stratification is nearly level, but slightly anticlinal, 
dipping a few degrees at the north and south sides. 

Some light is probably thrown upon the origin of these deposits by a 
section (Fig. 29) which was observed by the roadside between Ashland 
and Little Squam lake. On the surface was coarse upper till, 3 feet deep, 
showing no marks of stratification, and 


Upper till, 3 feet. 

Pebbly stratified CONnSisting of sand and gravel mixed 
clay, 10 feet. . 

Lower till. with abundant angular boulders of all 

ECTION IN ASHLAND. sizes up to four feet in diameter. Next 


was a dark blue clay, 10 feet thick, plainly stratified, but not finely lami- 


nated, and containing many fragments of rock up to six inches in diame- 
ter. Next below, and separated from the former at a definite line, was 
the compact unstratified lower till, which is here dark and clayey, and 
contains many glaciated stones up to a foot and a half in diameter. 

South of Squam bridge the steep north slope of a hill which rises from 
the shore of Little Squam lake has a layer of clay, stratified and free 
from pebbles, which is overlaid by one to three feet of till. The clay is 
four or five feet deep, but how much deeper is not known, and it is said 
to extend from near the lake shore to a height 150 feet above it. 

On the east side of Squam lake the farm of John Wiggin, in Moulton- 
borough, has frequent deposits of clay similar to that last described. At 
about fifteen rods south-west from the house and about 100 feet above 
the lake, this was used for brick-making fifty years ago. The side of Red 
hill, which rises near at hand on the east, is said to have in many places, 
to a height 300 feet above the lake, a stratum of clay underlying one to 
three feet of coarse till. On the north side of this lake the clay on land 
of the Messrs. George, in the south-west corner of Sandwich, which was 


MODIFIED DRIFT OF THE LAKE DISTRICT. 133 


extensively worked for brick-making fifty years ago, appears from de- 
scription to belong in the same class with the foregoing. 

No deposits of this kind were heard of about the north end of Winni- 
piseogee lake from the Wiers to Melvin Village. The well of Mr. Stock- 
bridge, in the eastern part of this village, about 25 feet above the lake, 
showed 6 feet of till underlaid by 10 feet of clay, followed by 6 feet of 
water-worn gravel, which contained copious springs. Less than a mile 
to the south-east a well at J. Tate’s showed 8 feet of coarse till and then 
4 feet of clay, underlaid by coarse, water-worn gravel. Chas. H. Copp’s 
well, 400 feet farther south-east, showed 4 feet of coarse till, underlaid 


by 23 feet of fine, stratified blue clay, beneath which ro 
water came in abundantly from a thin layer of gravel a A 
which rested on aledge. The former is about 30 and = 8 iia 
the latter about 50 feet above the lake. One mile ii L 
farther south a similar deposit of clay, about 30 feet 8 g 4 =O 
above the lake, has been used for brick-making. It #2 fii A Ba. 
lies a short distance east from the school-house near * Z Psa: 
the head of Twenty-mile bay. On the south-west Zs el ' 3 
side of Black island, a mile distant from Melvin vil- = H 1a g 
lage, two or three acres, 10 to 15 feet above the lake, 8 S es, a 
have a thin layer of till, with many large boulders on =. =| ve 3 
the surface, underlaid by clay, stratified and free from é a | oe — 
pebbles, at least four or five feet in depth. = : ie 

At Wolfeborough, the hillside of till south-east = 8 1 2 
from the bridge has an underlying stratum of clay. % 7 1 E 
Wells at the Glendon house, about 25 feet above the e a 1 Coes i 
lake, show some 6 feet of till, then an equal depth of a 8 i ara a 
clay with till beneath. Near the Pavilion, about 50 © ie Lae 
feet above the lake, a well showed 8 feet of coarse z z 1 as i 
till, then 2 feet of ferruginous earth, then 12 feet of 2 ~ tea Wo 
clay free from stones, underlaid by the compact stony 3 & : ee E 
lower till. About thirty rods south-east from the last © By ee, B 
a well passed through 8 feet of till, and then through : J gee 

ose 


4 feet of clay, which was underlaid by till. About 
the same distance farther south-east a well at J. Hanson’s found this layer 
of clay only one foot thick, occurring 10 feet below the surface. The last 


134 SURFACE GEOLOGY. 


two places are only a few feet higher than that near the Pavilion. Nearly 
all that part of the village which lies south-east from the bridge is built 
on a thick mass of till, which encloses a continuous stratum of clay. 
North-east from the Pavilion a slope descends in about twenty-five rods 
to a small pond, which is tributary to the lake and of the same height. 
This slope has a surface of till, with numerous boulders; but excavations 
for brick-making show that the clay beneath has a thickness of fully 20 
feet, with its bottom resting on till only a few feet above the lake. The 
till on the surface is 1 to 8 feet deep. This clay is free from pebbles, and 
is finely laminated in its lower portion, while its upper part sometimes 
crumbles into small angular pieces. No deposits of clay appear to occur 
in the thinner till which covers the hillside north-west from the bridge. 
At Clay point in Alton, three miles south-west from Wolfeborough, 
the lake shore rises steeply from Io to 4o feet, and from the top of this 
escarpment the surface, which is coarse till, has a very gentle upward 
slope. The lower part of this bank consists of a stratum of clay which 
was worked forty years ago for brick-making. This was at the end of the 
point where there 
was at least fifteen 
Upper till. feet, and perhaps 


Clay, 15 feet or ; 
more. considerably more, 


Gravel, 2 feet. 


Lower till. of finely laminated 


blue clay free from 


Fig. 31. Fig. 32. 

Map AND SECTION OF CLay Point, ALron. Scale of map, pebbles, with its 

I inch=} mile. Contour lines are shown for each Io feet bottom nearly at 
above the lake. 


the level of the 
lake. It was underlaid by a stratum of coarse, water-worn gravel, con- 
taining iron-rust. This abrupt bank, which extends around the point 
fully a quarter of a mile, has resulted from the excavation of the clay 
by the waves of the lake. 

Near East Alton, two miles south-east from this point, a bed of 
gravelly and somewhat stony clay, at least seven feet in thickness, is 
overlaid by two or three feet of till at a height of about 200 feet above 
the lake. A mile anda half west from this place, clay of good quality, 
finely laminated and free from pebbles, occurs on the north and north- 
west side of a hill, at a height of 150 feet above the lake. Both these 


MODIFIED DRIFT OF THE LAKE DISTRICT. 135 


deposits have been used for brick-making, and the latter has been exca- 
vated at two places an eighth of a mile apart. It is overlaid by about two 
feet of till, and a well showed the thickness of clay to be 13 feet, under 
which was a water-bearing layer of gravel. 

From this clay-bed a valley about 4o feet in depth descends to the 
south at the west base of the hill, which on this side is ledge. The bot- 


coe tom and the steep west side of 
Leet is Clay:beds. the valley are composed only of 
ae Bie modified drift, being fine silt or 
he Lines of section, and; while only till with many 
fig a." ™ large angular boulders up to 10 

Upper till. Sand. “Ledge. 


“ 
Mewes eww en eee eee 
Fig. 33.—MApP OF A SMALL AREA IN ALTON, _ Fig. 34.—SECTION CROSSING FIG. 33- 
TWO MILES SOUTH FROM CLAY POINT. Horizontal scale, 1 inch—} mile; ver- 
Scale, 1 inch=3 mile. Contour lines are tical scale, 1 inch—=400 feet. The 
shown for each 10 feet, the highest being dotted line at the base represents 
200 feet above the lake. the level of the lake. 


feet in size forms the top of its west bank and the irregular surface, 
which thence descends westerly to the alluvial area previously described 
on page a The contour of this locality is shown in Fig. 33; and Fig. 

: . 34 shows the apparent position of the sand 
underlying the very coarse till. Less than 
a mile farther south a similar valley is seen 
from the highway on its east side a short 
distance north of M. Adams’s house. The 
contour and probable section at this place 
are shown in Figs. 35 and 36. Here it 

Upper till. Sand. Upper till. 


Fig. 35.—Mapr OF A SMALL AREA w. comic ee E. 


IN ALTON, THREE MILES SOUTH 
FROM CLay Port. peers as Os SiS uta roe eee ne, 
Scale, 1 inch=3 mile. Contour Fic. 36.—SECTION CROSSING FIG. 3 Ge 
lines are shown for each 10 feet, | Horizontal scale, 1 inch—} mile; vertical scale, 


the lowest being 50 and the I inch= 400 feet. The dotted ine at the base 
highest 200 feet above the lake. fepresents the level of the lake. 


136 SURFACE GEOLOGY. 


appears that a thick deposit of sand underlies a thin surface of till upon 
a hillside between the heights of 100 and 200 feet above the lake. These 
localities have become noticeable because a great depth of sand has been 
excavated by rivulets. Probably thinner deposits of sand exist in many 
places underlying till, but not having an economical value like the clay, 
they have escaped notice. : 

At the north-west ends of Rattlesnake and Davis islands deposits of 
clay are found similar to that of Clay point, and in former times it has 
been excavated at both these places for brick-making. The same abrupt 
bank from 20 to 30 feet high forms the shore, and the surface of coarse 
till slopes gently upward from its top. The underlying clay-beds are free 
from pebbles and plainly stratified. 


Review and Conclusions. 


These numerous examples make it probable that many other similar 
deposits exist about these lakes, since their presence is not usually indi- 
cated on the surface. In considering the question of their origin, we 
notice that these beds of stratified clay and sand are uniformly overlaid 
by a comparatively thin covering of unstratified glacial drift, which in 
every instance is probably wholly made up of the loose, sandy, and very 
coarse material which we have called upper till. It is remarkable that 
no similar deposits are found on the hillsides without this thin covering 
of till, The examples found, however, do not lie in the pathway of any 
stream which could be supposed to bring the modified drift, or to exca- 
vate and carry it away if any had been left on the surface; instead of this 
they occur on the rounded slopes of hills at all heights from the lake 
shore to 200 or 300 feet above it. If any clay beds had been left in such 
situations without a covering of till, they would remain to the present 
time, and would be worked in preference-to others for brick-making. It 
is also remarkable that these deposits frequently extend in a stratum of 
varying thickness over a considerable area of hillside, sometimes appear- 
ing to be continuous upon a slope which rises 100 feet or more in vertical 
height. In all cases, however, where the stratification has been seen, it 
is approximately horizontal and not conformable to the slope. 

The section observed near Squam river in Ashland (p. 132) indicates 
the probable position and mode of formation of these deposits of clay 


MODIFIED DRIFT OF THE LAKE DISTRICT. 137 


and sand. They appear to lie between the two members of the coarse 
glacial drift, which we have denominated upper and lower till. In other 
portions of the state these are distinct from each other, and in a few 
instances they have been found to be separated by a thin layer of gravel 
or sand; but generally they are divided at a definite line, with no inter- 
vening stratum of modified drift, This section in Ashland shows that 
between the lower and upper till a depth of ten feet of stony stratified 
clay was deposited; and this seems to have taken place beneath the edge 
of the ice-sheet shortly before the completion of its melting, which con- 
tributed the three feet of upper till lying on the surface. 

The ice-sheet probably remained in a high mountain-like mass over 
these lakes after it had disappeared on each side from the basin of Ossi- 
pee lake and from the lower part of the Pemigewasset valley. As the 
melting continued, the drainage over this area was frequently obstructed 
because the ice-sheet retreated from the lines of water-shed towards the 
middle of these hydrographic basins. The water seems then to have 
melted large open spaces beneath the ice near its margin, in which beds 
of clay and sand were deposited. This would occur at the various heights 
and in the situations where these beds are found, and the till which over- 
lies them is shown by its material to be that which was contained in the 
ice-sheet and fell upon the surface when its melting was completed. We 
thus see how these deposits came to be spread over the slopes of the 
hills, thinly covered by large boulders and till. The frequent accumula- 
tion of such deposits in other parts of the state was prevented by un- 
obstructed drainage from the melting ice. This modified drift overlaid 
by till does not therefore appear to bear testimony to a warm inter-glacial 
period, or even to any retreat and subsequent advance of the ice. 

The course of the rivers which flowed from the melting ice-sheet over 
this area can still be pointed out. The extensive deposits of modified 
drift in New Durham and Alton mark a long continued outflow to the 
Cochecho valley. When the terminal front of the ice had retreated to a 
point a short distance north-west from Alton village, it seems to have re- 
mained nearly stationary during the deposition of the plain on which this 
village is built. At the same time the kame which lies between this 
point and Alton Bay was formed in an ice-walled channel. During the 


recent or terrace period portions of these deposits have been excavated 
VOL, Il. 18 


138 SURFACE GEOLOGY. 


by Merrymeeting river. The kames on the west side of Alton bay, a 
mile and a half farther north, were formed at a later date, while the outlet 
was in this direction. When the ice-sheet had retreated nearly to the 
mouth of this bay, the outlet from its melting over the lake at the north 
was along the low area a mile east of Fort point. As.the melting of the 
ice advanced towards the north-west, the kame-like terraces near West 
Alton, and those in the north-east part of Gilford, were probably depos- 
ited at the mouths of glacial rivers. Their height is that which the lake 
held when its outlet was to the Cochecho valley. The series of kames in 
Tuftonborough and Wolfeborough (p. 127) was probably formed at nearly 
the same time by a glacial river from the north-west, after the ice had 
disappeared from the south end of the lake and from the basin of Smith’s 
pond. The kames between Davis island and Lily pond indicate that the 
drainage from the ice-sheet was by this avenue before it was melted at 
the present outlet a mile farther west. A kame on the north side of Little 
Squam lake marks the outflow from the melting ice-sheet over that basin. 

The other deposits of modified drift about these lakes have been 
brought down by short streams, and are scanty in amount because the 
principal drainage of this area in the Champlain period was outward on 
all sides. They appear to have been formed in the same way that deltas 
are spread out nearly level at the mouths of tributary streams, often at an 
elevation much above the floods in the main valley. The height of the 
lakes during this deposition may therefore have been the same as now. 
If they had ever stood for any long period at a greater height, the hill- 
sides of till would be marked by a line like that of the present shore. 
This is mostly composed of till, which presents a wall of boulders four or 
five feet high, its finer portion having been washed away by the waves. 


MopiFieED DriFT ALONG MAGALLOWAY AND ANDROSCOGGIN RIVERS. 


Mr, J. H. Huntington has kindly supplied information in regard to the 
modified drift of the Magalloway and the upper portion of Androscoggin 
river. He has also mapped the alluvial areas along the Upper Ammo- 
noosuc river. The general geological map in the atlas shows the extent 
of these deposits in New Hampshire, so far as definite boundaries can be 
drawn.* 


* The Androscoggin river system is noticed in Vol. I, on pp. 224-226, 301, 309-311, and 322. 


MODIFIED DRIFT ALONG MAGALLOWAY RIVER. 139 


The level tracts on Magalloway river are described as especially re- 
markable for the occurrence of sloughs or small ponds, which are almost 
invariably found at a short distance on one or the other side of the 
stream. The river-banks are everywhere low, and the wooded plains, 
extending in places one half mile from the river, with a height rising 
from 10 to 25 feet above it, consist of gravel, which is not often so coarse 
as to have pebbles a foot in diameter. These are the characteristic feat- 
ures of this river for most of its length, both above and below Parma- 
chena lake. The only exceptions are the three or four miles just below 
this lake, and about two and a half miles, called Escahos falls, next above 
Wilson’s Mills, where only the glacial drift is present, over which the 
river descends in rapids obstructed by boulders. Along the greater por- 
tion of its course the descent is very slight, and the crooked stream winds 
slowly from side to side along its gravel plain. There seem to be no 
kames on either this or the upper part of Androscoggin river. 

The fine alluvium brought down by the Magalloway has filled up a 
considerable area about the mouth of Umbagog lake, forming an exten- 
sive bog at the border of the lake, and reaching a height of ro to 15 feet 
along the lower part of this river's course and on the Androscoggin to 
Errol dam. There are no rapids below Wilson’s Mills, and the Magallo- 
way is navigated as far as to Wentworth’s Location by a steamboat from 
the lake. On other sides this lake has mainly hilly and rocky shores. 
Its height is 1256 feet above the sea. 

Clear stream, along nearly its whole course from Dixville notch to 
Androscoggin river, is bordered by low sandy plains. 

The modified drift of the Androscoggin above Dummer, along the dis- 
tance which has no road, is described as consisting of tracts of swamp, or 
of stratified gravel and silt in some places one half mile in width, having 
a height of 10 to 25 feet. These are along level portions of the river, 
which alternate with rapids where the glacial drift, or till, extends in gen- 
tle slopes to the stream. 

The exploration of the Androscoggin river, with special reference to its 
modified drift, extended nearly to the east line of Dummer. Below this 
point the river flows south-westerly four miles to Pontoocook falls, and in 
this distance is bordered on the north-west side by considerable areas of 
alluvium from 20 to 30 feet above the river, extending from one half to 


140 SURFACE GEOLOGY. 


three fourths of a mile wide on Newell’s brook, and on the stream which 
is the outlet of Dummer ponds. These tracts consist mainly of sand or 
fine silt, and are very level and in many portions swampy. On the south- 
east side the river is bordered by a narrow margin of modified drift, 
beyond which the hills rise from 100 to 200 feet above the stream, 

Pontoocook falls extend about a mile from the most western point 
reached by the river, which here flows between hills of till or ledge. 
Near the foot of these falls is Pontoocook bay, which is an expansion of 
the river containing several islands. This is bordered by sandy terraces ; 
and thence southward for ten miles, extending through Milan and nearly 
to Berlin falls, the modified drift is continuous, being usually one eighth 
to one third of a mile wide upon both sides of the river. This consists 
of sand or gravel, which is not often very coarse. About half of its 
whole width is interval, being from 5 to 15 feet above the ordinary 
height of the river; and all above this is irregular in contour, with no 
well defined terraces, the modified drift reaching in irregular slopes about 
40 feet above the river. The Androscoggin along this distance is nearly 
level, having a height of about 1,050 feet above the sea; and the hills on 
each side are of moderate height and gentle slopes. 

At Berlin Falls the precipitous front of Mt. Forest rises close at hand 
on the west, and the river here enters the White Mountain area, Along 
the rest of its course in New Hampshire, and for some distance in Maine, 
the valley is closely bordered by high and abrupt mountains. From the 
head of Berlin falls the river descends nearly 200 feet in the first mile, 
and its current is rapid to the east boundary of the state, which it crosses 
at a height of 690 feet above the sea. For the first five miles of this dis- 
tance the course continues to the south towards the highest of the White 
Mountains; but at Gorham the river turns at a right angle, arid after flow- 
ing nine miles to the east it enters Maine. The very rapid portion of the 
river at Berlin Falls is destitute of any modified drift, and the channel is 
principally ledge. Below these falls the modified drift through Gorham 
and Shelburne is continuous on one or both sides, though often narrow, 
and it is nowhere more than a mile between the steep mountain walls 
which enclose the valley. 

Through Gorham, the terraces which border the Androscoggin are 10 
to 50 feet in height, and they are best shown on the west and south sides 


MODIFIED DRIFT ALONG ANDROSCOGGIN RIVER. I4!I 


of the river. They consist almost wholly of gravel, which is often very 
coarse, and in the highest terrace is sometimes but slightly water-worn, 
and scarcely distinguishable from till. At the sharp bend of the river, a 
mile north-west from Gorham village, three terraces occur on the east 
side, 10, 20, and 40 feet in height. The latter appears to represent the 
ancient continuous flood-plain at the close of the Champlain period. The 
village of Gorham is built on a lower terrace, 25 feet in height, which 
extends nearly level for a mile between Moose and Peabody rivers. Re- 
mains of the ancient flood-plain form terraces of coarse gravel, from 20 to 
30 feet higher, which occur on the north side of the Androscoggin oppo- 
site the mouth of Moose river, on the south side of the railroad in the 
west part of the village, and on Academy hill, which is an isolated rem- 
nant that escaped erosion because partly protected by ledges. 

Peabody river, for a mile before entering this valley, is bordered by 
steep banks of extremely coarse modified drift, or perhaps till, from 40 to 
100 feet high. The space between these banks was formerly filled with 
similar material, which has been excavated by the stream during the 
recent or terrace period. 

In Shelburne the modified drift occurs principally at two heights. The 
upper terraces are the remnants of the river’s flood-plain in the Cham- 
plain period. They are from 50 to 60 feet above the river, with a nearly 
level surface, and bordered by steep escarpments. Their material is 
usually gravel, which is frequently very coarse, but in some places it is 
mainly sand. A mile and a half east from Shelburne village, several 
small ponds occur in hollows upon this terrace plain. The lower terrace 
is interval, being only from 5 to 15 feet above the ordinary height of the 
river. 

It is a noticeable feature of the intervals of this part of the Andros- 
coggin and of the upper portion of Saco river, that they are often com- 
posed of a substratum of coarse gravel, containing pebbles one foot or 
more in diameter, above which is a layer of fine silt three to six feet 
thick forming the surface. The coarse gravel is like that which often 
forms the river’s bed in the vicinity of the mountains; and these sections, 
which are exposed in the banks now being undermined by the river, show 
that it formerly had its channel in nearly the same place as now but at 
a greater height, having flowed upon the surface of the layer of gravel, 


142 SURFACE GEOLOGY. 


Since that time the river has been changing its course, and the overlying 
fine silt has been deposited from its floods upon the deserted river-bed. 


MopiFflep Drirr ALONG Saco RIVER AND IN THE BASIN OF OSSIPEE 
LAKE. 


The areas which are occupied by modified drift in this part of the state 
are delineated on the general geological map in the atlas; and a special 
map on Plate VI shows the extensive plains about Ossipee lake.* 

The south-eastern part of the White Mountain district is drained by 
the Saco, which has its farthest sources in Saco pond and Mt. Washing- 
ton river. The water-shed at the Crawford house, which divides this 
from the Lower Ammonoosuc river, is formed by a deposit of very coarse 
modified drift (p. 62), which was swept down into this mountain pass in 
the Champlain period. Its height is 1,900 feet above the sea; and Saco 
pond, which fills a depression in this deposit, is 20 feet lower. The small 
stream which issues from this pond passes through the White Mountain 
Notch, falling 600 feet in the first three miles, and nearly as much more 
in the next nine miles. Along this distance it flows between lofty moun- 
tains, whose sides are often precipitous walls of rock. A fine view of 
this part of its valley is afforded from the top of Mt. Willard. Far above 
rise the rugged heights of Webster and Willey, almost vertical in their 
upper part, but below bending in graceful, regular curves, composed of 
materials which have fallen from each side and form an apparently 
smoothed hollow for the highway and river. The principal superficial 
deposits along this steep portion of the river are such rocky débris which 
has crumbled from the mountains, or the equally coarse unstratified till. 
In the bed of the stream these materials have become water-worn, but 
only limited deposits of gravel and sand are found. It is worthy of note, 
that in constructing the Portland & Ogdensburg Railroad the excavations 
yielded an abundance of sandy gravel suitable for ballast. To make a 
gradual ascent, this road is built along the side of the valley; and some 
of these excavations were two or three hundred feet above the stream. 

At the west line of Bartlett the Saco is 745 feet above the sea. In the 
next eight miles to the mouth of Ellis river, it descends about 30 feet to 


* This river system is described in Vol. I, on pp. 302, 311, and 312. 


MODIFIED DRIFT ALONG SACO RIVER. 143 


the mile, flowing over modified drift. This consists of gravel and sand, 
and above the Rocky Branch these occupy an area one fourth to one half 
a mile wide, which lies mostly on the south side of the river, forming a 
nearly continuous interval 10 to 15 feet in height, which slopes with the 
stream, and irregular terraces which reach 25 feet higher. 

From the Glen station in Bartlett to Conway Corner the alluvial area 
averages fully a mile in width, lying in nearly equal amount on each side 
of the river. The greater portion of this is interval, from 10 to 20 feet 
in height, which is often seen to be composed of coarse gravel overlaid 
by fine silt, as on Androscoggin river. The flood-plain of the Champlain 
period is shown in the higher terraces of sand or fine gravel, 40 to 60 
feet above the river, which are nearly continuous on both sides. North 
Conway is built on a wide portion of the east terrace. The form of these 
terraces, with their surface level but usually narrow and bounded by steep 
escarpments, and their correspondence in height on opposite sides of the 
valley, make it easy to understand that a wide plain once reached across 
the intervening area. 

Along Seavey’s falls, which extend about a mile east from Conway 
Corner, the Saco is bordered on both sides by slopes of till and ledge. 
The modified drift of the highest terrace, however, is continuous between 
Pine and Rattlesnake hills, and thence extends two miles to the east on 
the north side of the river; and on the south it reaches from Conway 
Centre to the north-east side of Walker’s pond, and thence is nearly con- 
tinuous, though narrow, eastward to Maine line. East from the outlet of 
Walker’s pond, the interval between this terrace and the river on the 
south is not wide, but on the north it extends one half to one mile from 
the river, rising with a gentle slope to a height about 25 feet above it. 
On this side, the most elevated part of the alluvial area, as at Conway 
Street, is only a few feet above the reach of high water. The ancient 
flood-plain, which was from 40 to 50 feet above the present river, as 
shown by its terrace on the south, may have extended over this whole 
area, It would then appear that the river here began its excavation on 
the north side, and has been gradually cutting its channel deeper and 
deeper as it has slowly moved across this area southward. Remnants of 
the former high flood-plain are thus found at a nearly constant height 
above the river for fourteen miles, sloping in this distance more than 100 


144 SURFACE GEOLOGY. 


feet. The height of Saco river at the state line is about 400 feet above 
the sea. 


Kames between Saco River and Six-Mile Pond. 


Along the Portsmouth, Great F alls & Conway Railroad a very remark- 
able series of kames extends six miles, from near Conway to Madison 
station. The railroad survey shows that the water-shed here is very low. 
It is 516 feet above the sea, being only 70 feet above the Saco river at 
Conway, and only 60 feet above Six-mile pond (also called Silver lake). 
This low avenue is one half mile to one mile wide, extending nearly from 
north to south; it is bordered on both sides by hills from 300 to 500 feet 
higher, those on the west side rising in almost perpendicular cliffs. The 
kame begins at Pequawket pond, a mile south-west from Conway Corner 
and Saco river. A ridge 4o feet high forms the west shore of this pond, 
and is thence nearly continuous for about three miles southward, lying 
on the east side of the railroad and Pequawket brook, which drains the 
part of this low valley that is tributary to the Saco. This kame is nearly 
straight, and for the most part consists of a steep narrow ridge 40 to 75 
feet high, being composed of interstratified sand and coarse gravel, with 
occasional large boulders. A quarter of a mile south-west from Pequaw- 
ket pond the top of this kame becomes 200 to 300 feet wide, and is level 
like a terrace. An excavation shows that the stratification here is nearly 
horizontal in the interior of the deposit, which is sand or fine gravel, but 
it is abruptly inclined on its west side, conformably with the slope of the 
kame. Low, swampy areas and occasional small ponds lie on the west 
side of this kame, and are interspersed farther to the south among irreg- 
ular ridges and mounds. These unfilled depressions prove that very lit- 
tle erosion has been effected by the present streams; and that these 
deposits of modified drift owe their form to deposition in the channel of 
glacial rivers, while the ice remained unmelted on each side. 

The southern part of this series of kames lies principally on the west 
side of the railroad, covering an area a third of a mile wide, and bounded 
on the west by the precipitous face of Pine and Hedgehog hills. Along 
the lowest part of the valley, near the railroad, the ridges consist mainly 
of gravel with little clear sand, and are much coarser than in the north 
part of the series; but their pebbles are plainly rounded, and of such 


MODIFIED DRIFT IN OSSIPEE BASIN. 145 


size as could be transported by strong currents of water. These kames 
are from 25 to 50 feet high, and extend in crooked north and south ridges 
which are frequently traceable a quarter or a half mile. Large angular 
boulders are occasionally found embedded in these water-worn deposits. 
In going westward we find these boulders more numerous; and the 
ridges, which become shorter and more irregular, are composed partly 
or wholly of angular materials. Near the foot of the hills these ridges 
reach about 100 feet above the railroad, and present the very irregular 
contour of typical kames, having steep sides and narrow tops, and enclos- 
ing bowl-shaped hollows; but they consist entirely of angular débris with 
no water-worn deposits, and in many places their surface is composed 
only of boulders with no earth to fill the interspaces. Between these 
moraines and the true kames seen along the railroad there is a gradual 
transition, the intervening ridges being partly morainic and partly kame- 
like in material. 

A considerable area of low alluvium, without ridges, lies east of Madison 
station, separating this long series of kames from others of coarse water- 
worn gravel, which occur on the north-east shore of Six-mile pond. Near 
the head of this pond a similar ridge forms a small crescent-shaped 
island, concave towards the north. ; 


Plains in the Basin of Ossipee Lake. 


On the north-west side of Six-mile pond no distinct kames were seen, 
but deposits of very coarse water-worn gravel, with the largest pebbles 
one or even two feet in diameter, rise from 25 to 50 feet in irregular 
slopes. The level plains begin about three fourths of a mile south from 
Madison station, and the material in the next three miles gradually 
changes to very fine gravel or sand, so that the railroad cuts at the south 
end of this distance rarely show pebbles an inch in diameter. These 
plains occupy a large area in the south-west corner of Madison and the 
east part of Tamworth, and extend south along Six-mile brook, which 
separates Freedom and Ossipee, to the north-west side of Ossipee lake. 
(Plate VI.) Their soil is barren, its natural woody growth being scrub 
oaks and pitch pines. Their height at the north is about 4o feet above 
Six-mile pond, which is 456 feet above the sea; thence they have a 


slight southward slope of 15 or 20 feet in a mile, descending nearly to 
VOL. III. 19 


146 SURFACE GEOLOGY. 


the level of Ossipee lake, which is 408 feet above the sea. In their west- 
ern portion they are from 40 to 50 feet above Bear Camp river, which 
along its last six miles flows through fertile intervals. These cover areas 
from which the river has excavated the higher plain. The upper part of 
this river is also frequently bordered by intervals and terraces. 

The shores of Ossipee lake are mostly low; and it appears that this 
area remains unfilled because sufficient material has not been supplied by 
inflowing streams. We cannot thus explain the unfilled hollows of Six- 
mile pond, and of Elliot and White ponds in Tamworth; for the level 
plain adjoining them is from 25 to 40 feet in height, and descends steeply 
to their shores. Probably masses of ice filled these depressions while 
the bordering plains were being deposited. 

Till extends in a gentle slope to the margin of Ossipee lake along a 
distance of about a half mile on its north-east side. Barren pine-plains 
reach thence for three miles to the east. These are divided by the irreg- 
ular chain of Danforth ponds, which have the same height with the lake. 
At Danforth bridge these plains are nearly level, and have a height of 
35 feet above the ponds, to which they descend in steep escarpments., 
Their material is mainly sand or fine gravel; but coarse gravel, con- 
taining pebbles from six inches to one foot in diameter, is occasionally 
found, and appears to belong to kames which have been nearly buried 
beneath the fine alluvium. 

Ossipee river, the outlet of this lake, flows over till at Effingham falls, 
and along its last mile before entering Maine. In the intervening three 
miles it is bordered by low modified drift, which extends to Swasey pond 
in Freedom, and forms an extensive tamarack swamp in the north-east 
corner of Effingham. 

On the west and south sides of Ossipee lake the modified drift is one 
half mile to a mile and a half wide. Its highest portion is a delta-plain on 
the north side of Lovell’s river, 40 feet above the lake. Elsewhere it is 
low, being swampy in many places, and rises only 15 to 25 feet above the 
lake, towards which it slopes. 

These nearly level areas are bounded by hills and mountains, which 
rise steeply from the edge of the plains. The supply of modified drift 
was very abundant here, and fills three fourths of the natural lake-basin 
which is thus enclosed. 


ips enclosed. 


| Modified Drift 


This horder: is the true meridian for all the ma, 


Ke Pe 
EasTERN N.H. 


Zz 


IN 


Explanation. 
Bdge of Glacial Drift, ges 
Boundary hetween Terraces,----- i 
Gravel ridges, or Kames, wn | 
Ancient River-beds, +)... 
Roads with houses, -.——— 
Figures denote hei 


, infect above the sea. Ossicte 


— or — 


Green Mr. 
Ossipee Lake. \ 
febRioie ls 


'.NGHAM 


eH Dune, 550. 
<a — 


Salmon Falls 


———AND 


: Ss Cochecho Rivers. 


HELIOTYPE. 


MODIFIED DRIFT ALONG PINE RIVER. 147 


A conspicuous dune, blown 125 feet above the low plains, occurs two 
miles south-east from Ossipee lake on the west foot-slope of Green moun- 
tain. A track of sand-drifts, now grassed over, reaches up to this from 
the north-west; and an old pine stump, standing where it originally 
grew, shows that since the clearing of the country a portion of the dune 
seven feet in depth has been swept from beneath it by the winds, being 
carried to the south-east and somewhat higher up the hillside. 


Kames along Pine River. 


South-east from Ossipee lake a continuous belt of modified drift ex- 
tends along the entire course of Pine river, forms the water-shed between 
Pine River pond and Balch pond, and thence continues eastward along 
Little Ossipee river in Maine. These ponds are about 20 and 40 feet 
respectively below the lowest point of the water-shed, which is about 550 
feet above the sea, or 140 above Ossipee lake, 12 miles distant. The 
width of the modified drift here is fully a mile, and it is not much nar- 
rower at any point. It occupies a comparatively straight valley, which is 
commonly bordered by high hills at each side. An exception to this is 
found in the south part of Effingham, where level sandy plains about 500 
feet above the sea extend nearly continuous from Pine river to Prov- 
ince pond. Other level plains occur, as south-east of Duncan lake, be- 
tween North Wakefield and the mouth of Pine River pond, and east of 
East Wakefield depot ; but the greater part of this modified drift has an 
uneven surface, presenting small hollows, ridges, and mounds; and prom- 
inent kames, in ridges from 75 to 125 feet above the river, extend along 
the middle of the valley. 

This series of kames or gravel ridges borders Pine river south-east from 
Ossipee Centre, but it is not well shown at the bridge in Effingham. Two 
miles farther south, where there were formerly a bridge and mills, it con- 
sists of a single narrow ridge, 100 feet above the river which flows at its 
foot on the east, and 30 feet above the plains which extend a mile south- 
west to Duncan lake. One mile southward this principal kame of the 
series is said to lie between White and Black ponds. Opposite Ossipee 
Corner the river crosses the line of this ridge, a half mile of which has 
been swept away. It next appears east from the mouth of Poland brook, 
and extends in a single ridge a mile to the south, with a height 50 to 75 


148 SURFACE GEOLOGY. 


feet above the low modified drift on each side, or about 100 feet above 
the river. It is then cut through by the river, but only a short gap is 
made; and it continues thence unbroken for more than a mile to the 
south-east, forming a nearly straight ridge 75 to 125 feet high on the 
west side of the river. On its east side the modified drift is narrow; and 
the road passes over a hill which affords a fine view of this kame, and 
others of less height which extend parallel with it, and fill nearly the 
whole valley for two miles below Pine River pond. At the mouth of 
this pond the principal kame seen was just north-east of the bridge, with 
a height 40 feet above the river. Kames of the same or less height occur 
along the shores of this pond, and form its islands. The water-shed be- 
tween Pine River and Balch ponds is an area of kames, its lowest point 
being a hollow between high parallel ridges; and the same series con- 
tinues south-east along the sides of Balch pond. 

The material of these ridges is almost wholly water-worn, wherever it 
has been observed. It consists principally of gravel, which contains peb- 
bles or rounded boulders up to two or three feet in diameter. Layers of 
sand are sometimes interstratified with this gravel; and angular boulders 
up to five or six feet in diameter are occasionally found. The more level 
areas of modified drift in this valley are also mostly gravel, with the larg- 
est pebbles frequently six inches to one foot in diameter. 

The height of this series of kames where it is first met with, one to 
two miles above the mouth of Pine river, is about 40 feet above the lake, 
or 450 above the sea. At the water-shed between Pine River and Balch 
ponds it is about 600 feet above the sea. From this point the kames 
descend both to the south-east and north-west with the valleys, their 
slope along Pine river being 15 feet to a mile. 

The accompanying plains along the lower part of Pine river are only 
10 to 25 feet in height. At North Wakefield they are 60 feet above the 
river and pond; at East Wakefield depot they reach their greatest height, 
being 675 feet above the sea, or more than 100 feet above the lowest de- 
pression of the water-shed. The same belt of modified drift continues 
into Maine, forming extensive low plains in Acton and Shapleigh, with a 
height about 500 feet above the sea. 


MODIFIED DRIFT ALONG PINE RIVER. 149 


Review and Conclusions. 


From the modified drift of Pine river, Ossipee lake, and Saco river, we 
learn the history of this part of New Hampshire in the Champlain period. 
After the ice-sheet had retreated from the coast, it seems for a long time 
to have still covered the Ossipee Lake basin, and the valley of Pine River 
and Balch ponds. The kames of this valley were deposited during this 
time in the channel of a glacial river, which carried forward its finer 
gravel and sand to form the plains that extend south-east from Balch 
pond. The coarse material and irregular surface of nearly all the modi- 
fied drift along the upper part of Pine river indicate that masses of ice 
still remained at the time of its deposition. 

After this, the ice-sheet disappeared from the broad low basin of Ossi- 
pee lake, and again for a long time had its terminal front at the border of 
the low area from which it had retreated. Its moraines fill the west and 
higher side of the narrow valley between Madison and Conway. These 
gradually change as we come to the centre of the valley to ordinary 
water-worn kames. This appears to have been the first outlet from the 
melting of the ice-sheet over the Saco valley and the south-east side of 
the White Mountains; and the material brought down was spread out to 
form the extensive sand and gravel plains about Ossipee lake and Six- 
mile pond. The comparatively small amount of levelly stratified drift 
associated -with the kames in Madison and Conway makes it probable 
that the present outlet by Saco river was opened before the ice here had 
wholly disappeared, so that the later alluvium was carried by this river 
into Maine. 


MopiFiep DRIFT IN THE BAsIN oF PiscaTAQuA RIVER. 


Under this title are embraced nearly all our observations in Strafford 
and Rockingham counties. The streams which drain this district are 
united before reaching the ocean in Great bay and Piscataqua river.* 
Salmon Falls and Cochecho rivers are the largest of these, and have 
been the most thoroughly explored. Wide plains extend between these 
rivers in Rochester. Very interesting kames and kame-like plains occur 


* The topographic features of this basin are described in Vol. I, pp. 213-215, 302, and 313. 


150 SURFACE GEOLOGY. 


about Dover, and are found frequently southward through the state. 
Isinglass, Bellamy, Oyster, and Lamprey rivers are known to be bor- 
dered in many places by intervals and low terraces and plains, but their 
modified drift has not been specially explored. 

The valley of Exeter river contains large areas of modified drift. One 
of these diverges from this river at the south-east corner of Fremont, and 
extends to the south through Kingston, Newton, and Plaistow to Haver- 
hill, Mass. This belt of modified drift reaches nearly fifteen miles, and 
is continuous from the Exeter to the Merrimack river. Along most of 
this distance it forms extensive plains. Several ponds in Kingston, which 
lie in depressions of these plains, are the sources of Powow river. 

In Newington and Portsmouth a kame-like plain of gravel and sand is 
the highest land between Great bay and the Piscataqua river; but their 
shores, with the islands of this river below Portsmouth, are almost every- 
where gently-sloping hills of till or ledge. 

Marine shells and other organic remains have been found in the lower 
portions of this valley, showing that the ocean stood at a higher level 
when the modified drift in which they occur was deposited. The more 
particular description of this district will be taken up in the same order 
as in the foregoing summary. 

Salmon Falls River. The source of this stream is East pond, which 
lies partly in Wakefield and partly in Acton, Me. It has an area of 
nearly three square miles, and a height about 500 feet above the sea, 
below which it can be drawn 18 feet, to supply the mills at Great Falls 
and Salmon Falls. This river and the Piscataqua form a part of the 
eastern boundary of New Hampshire. The descent below East pond is 
shown by the following heights, which are in feet above the sea: Horn 
pond, 479; at Milton Mills (fall), 440 to 416; at Milton Three Ponds 
dam, 412 to 400; above East Rochester, about 200; at Great Falls, 166 
to 90; at Salmon Falls, 65 to 25; at South Berwick, 20 to tide-water. 
Salmon Falls and Cochecho rivers, along their lower three miles, and the 
Piscataqua river, which is the name applied below their junction, are af- 
fected by the tide, and flow with a strong current alternately towards and 
from the sea. 

The north-west side of East pond is bordered by a low and partly 
swampy area of modified drift, which reaches a quarter to a half mile 


MODIFIED DRIFT IN PISCATAQUA BASIN. 151 


in width, enclosing Round pond. Except on this side, its shores are till 
or ledge. No examination has been made between this pond and Milton 
Mills. In the two miles from this village to Branch river, the modified 
drift rises in irregular slopes to a height of 20 or 30 feet. 

Along Branch river the modified drift is well shown, forming swampy 
areas and terraces of sand or gravel 20 to 40 feet in height. Kames 
were noted in Wakefield a quarter of a mile west from Wolfeborough 
Junction, and at several other points southward to Union village. At 
one half mile to two miles south from this station they are finely dis- 
played along the railroad, mostly on its west side. They are composed 
of coarse water-worn gravel, in ridges 25 to 40 feet high, with their trend 
generally north and south. These kames descend with the valley from 
about 575 to 475 feet above the sea. 

The valley of Salmon Falls river in Milton contains three natural 
ponds, through two of which the river flows. The two south-west ponds 
lie near the east foot of Teneriffe mountain. They are bordered by 
kames on their west and south sidés; and low, sandy plains extend be- 
tween them and the North-east pond. They are all flowed to the same 
height by the dam at Milton Three Ponds village, which has been re- 
cently raised a few feet, overflowing a large meadow above North-east 
pond, and holding the river level six miles, or to within a half mile of 
Milton Mills. Below this dam the river descends about 200 feet in the 
next three miles, its channel lying between ledges or steep slopes of till. 

The next modified drift is in the north part of Rochester (Plate VI, 
p. 146), where for a distance of two miles it occupies the entire area a 
mile and a half wide between Salmon Falls and Cochecho rivers, This 
tract is crossed by the Portsmouth, Great Falls & Conway Railroad. It 
consists of sandy plains, 25 to 40 feet above the river, or of extensive 
swamps and peat-bogs. The latter were scantily filled with modified 
drift, while it was more abundantly supplied on all sides, preventing 
drainage. Salmon Falls river here turns to the south-east. A straight 
course would carry it southward across this area, bringing it to a junc- 
tion with the Cochecho at Rochester. In the Champlain period the 
highest floods of these rivers were united here, and nearly all the modi- 
fied drift which they brought down was deposited in these plains. 

At East Rochester a narrow belt of alluvium, from 20 to 30 feet high, 


I§2 SURFACE GEOLOGY. 


borders the river. In the north part of Somersworth, sand and ordinary 
gravel extend from the river to the railroad and Cole’s pond. These de- 
posits lie in irregular slopes, nowhere presenting the usual level terraces. 
Thence very coarse kame-like gravel, spread out in level plains, extends 
southward, and forms the water-shed west of this river to Willand pond. 
In the next four miles to Salmon Falls, east of these kame-like plains, 
the valley of the river consists of till or ledge. 

Below Salmon Falls the river has excavated its channel between prom- 
inent terraces, upon which the villages of South Berwick and Rollinsford 
are built. Their height is nearly the same at both sides, being about 80 
feet above the river, or 100 feet above the sea. The same terrace-plain 
extends west to Rollinsford junction, where its height is 115 feet above 
the sea. The last mile and a half of this river is bordered on both sides 
by level plains about 4o feet in height. On the west these are a half 
mile wide, terminating in Rollinsford point. 

Cochecho River. The water-shed between Winnipiseogee lake and this 
river is composed of modified drift (p. 130), which is very scanty or want- 
ing along the next four miles to Farmington. Three streams, which are 
the head waters of this river, have here brought down large amounts of 
gravel and sand, forming the low and partly level area west of Farming- 
ton village. Below this place the modified drift, lying principally in 
kames, or irregular mounds and ridges, is continuous on both sides of 
the river, being one half to three fourths of a mile wide for five miles, 
beyond which it expands into the extensive plains of Rochester. These 
mounds and ridges rise from 20 to 30 feet above the intervening hollows, 
reaching a height about 50 feet above the river. Their material is coarse, 
water-worn gravel, with occasional layers of sand; and sections usually 
show an anticlinal or arched stratification. A half mile east of Farm- 
ington these kames enclose numerous bowl-shaped depressions, some of 
which contain small ponds. This part of the Cochecho valley is bordered 
on both sides by hills, which rise 300 to 400 feet above the river. 

Two and a half miles above Rochester the area of modified drift widens 
on the east, reaching to Salmon Falls river (Plate VI, p. 146). Thence 
level, sandy plains, in many places underlaid by clay, extend along the 
Cochecho eight miles. The coarse kame-like gravel continues on the 
west side of the river nearly to Rochester; but the wide plains at this 


MODIFIED DRIFT IN PISCATAQUA BASIN. 153 


place consist wholly of fine alluvium, and no coarse deposits were seen 
farther south. Below Gonic these plains extend a mile wide to a distance 
of two miles west from the Cochecho, and, excepting isolated hills, they 
occupy the whole area between this and the Isinglass river. 

The height of these plains at Rochester is 226 feet, and at Gonic 200 
feet above the sea, being at each place about 30 feet above the river. 
Southward, the stream falls more rapidly than the plains, lying 75 feet 
below them in the south part of Rochester. 

These deposits terminate near the mouth of Isinglass river; and the 
next four miles of the Cochecho valley are destitute of modified drift, 
which next occurs a fourth of a mile above the city of Dover. The river 
has here cut through the ridge of a kame which extends from the kame- 
like plain of Willand pond to that of Pine Hill cemetery. These were de- 
posited by glacial streams, while the ice-sheet still remained unmelted on 
both sides. After the ice had disappeared, Cochecho river brought down 
the alluvial plain, composed of clay overlain by sand, on which the north 
part of the city is built. The south part of this plain has been exca~- 
vated by the river, leaving the rest in the form of a terrace. Its height 
is 70 feet above tide-water, which extends to its foot at Dover landing. 
East of the city the river is again bordered by slopes of till or ledge. 


Fig. 37.—OBLIQUELY STRATI- Fig. 38.—SECTION IN CLAY, RocH- 
FIED SAND, ROCHESTER. 


‘ Scal arnt ESTER. 
ete, Taner StOEeS Scale, 1 inch=10 feet. 


Beds of clay are worked for brick-making a half mile south from the 
Rochester depot, on the east side of the railroad, and a half mile farther 
south on the west side of Cochecho river. At the former brick-yard the 
clay is overlain by 5 to 8 feet of sand, which occurs principally in layers 
separated by nearly level lines, as shown in Fig. 37, but obliquely lami- 
nated with varying southward dip. About 15 feet of clay is exposed 
here, the upper part being gray, and most of the lower part dlue, defi- 
nitely separated from each other. The section shown in Fig. 38 was 

VOL, III. 20 


154 SURFACE GEOLOGY. 


observed near the south end of this brick-yard. A mass of uniformly 
blue clay occupies a wedge-shaped space in the midst of gray clay. No 
difference, except that of color, could be seen; and the lines of stratifica- 
tion are plainly continuous through both. 

At the second brick-yard 3 feet of sand overlies 15 feet of clay, which 
rests on a ledge. The upper part of this bed is compact gray clay, in- 
clined to break into small fragments, the sides of which are stained with 
iron-rust; its lower portion is tenacious, and bluish gray in color. 

Near Gonic the stratum is worked at four places, all on the east side 
of the river. Here the surface is 1 to 4 feet of sand. Next follows 10 
to 15 feet of gray clay; this changes abruptly to blue clay, which is sev- 
eral feet thick, and extends below the excavations. 

The brick-yard at Dover landing shows the following deposits, sepa- 
rated by definite lines: Sand at the top, 8 feet; gray clay, 12 feet; blue 
clay, 15 feet. A brick-yard beside the Piscataqua river, half a mile north 
from Dover point, shows 30 feet of clay,—its upper portion gray and its 
lower portion blue. The brick-yards on the south-west side of this point 
expose only the gray clay, which is about 15 feet thick, overlain by 2 or 3 
feet of sand. We find here the features which usually mark the gray 
clay. Near the top it is free from sand, and is hard and compact, not 
showing its stratification, but breaking into small angular pieces, which 
are separated by films of iron-rust. In its lower part it shows lines of 
stratification, and sometimes contains sandy layers. Through the whole 
deposit pebbles up to six inches or one foot in diameter are rarely found. 
A well at one of these yards showed the bottom of this gray clay inter- 
stratified with sand and gravel, beneath which was blue clay. 

The brick-yards along the Boston & Maine Railroad are similar to the 
foregoing. Half-way between the stations of Exeter and East Kingston 
beds of clay are found in kame-like banks, 20 to 30 feet in height, at both 
sides of the railroad. The top of these deposits is a few feet of sand or 
fine gravel, irregularly bedded as if laid down by strong and conflicting 
currents. The clay is nearly level in its stratification, and has a depth of 
about 20 feet. It is principally gray, but changes gradually near the bot- 
tom into blue clay. Another brick-yard of the same kind is found a mile 
farther south. These seem to be isolated deposits, having been formed 
like the kames in hollows of the melting ice-sheet. They lie on the till, 


MODIFIED DRIFT IN PISCATAQUA BASIN. 155 


and can hardly be supposed to be remnants of any formerly level deposit. 
The beds of clay near Dover point may be of similar origin. 

The clay worked at Plaistow is alluvial, and was deposited in the quiet 
water, held back by a barrier of kames. The order here is as follows: 
sand at the top, 5 to 10 feet; gray clay, about 10 feet ; gradual transition 
from gray to blue clay, 3 feet; blue clay, 5 to 10 feet, underlain by sand. 

Beds of gray and blue clay are also found in the high terraces of Mer- 
rimack river, and in the valley of Hudson river and Lake Champlain (see 
pp. 94 and gs). In Vermont, where they contain marine shells, they 
were called by C. H. Hitchcock Champlain clays, from which this name 
has been applied to the period in which the ice-sheet disappeared. 

The height of these deposits of clay in Hooksett and Pembroke is 
about 300 feet above the sea; in Rochester, about 200; at Dover Land- 
ing and Point, 20 to 50; and in East Kingston and Plaistow, about 100. 

The wide distribution and unvarying order of the gray and blue clay 
suggest that they have some special meaning, which it may be important 
to understand for the right interpretation of our other records in surface 
geology. To what conditions and causes do these clays owe their differ- 
ence in color?* Without being able to explain this, we have presented 
our observations as fully and plainly as possible. 

Kames and Kame-like Plains about Dover and southward. Near the 
coast from Dover to Newburyport are frequently found massive kame- 
like deposits, consisting of high plains or broadly rounded ridges of gravel 
and sand, which often form water-sheds between wide valleys 100 to 200 
feet below. The absence in these valleys of the terraces which mark 
erosion through modified drift, shows that they were never filled with the 
same materials, and that these remarkable plains and ridges were depos- 
ited in their present isolated position, with wide areas of lower land at 
each side. How this took place we can only explain by referring the 


* These clays were the most finely pulverized portion of the abraded material contained in the ice-sheet. Their 
iron, which is always present in such quantity as to give the burnt bricks a red color, was in the same state of 
combination as in the rocks before pulverization, principally in ferrous sulphides, silicates, and carbonates. This 
is its condition in the dark and often blue clayey paste of the lower till. Has the underlying blue clay been washed 
from the ice-sheet by glacial rivers, transported many miles, and deposited, without the separation and further 
oxidation of its iron, which would give the clay a gray, brown, or reddish color? and have these changes been 
partially effected in the overlying gray clay? Or, did these changes take place quite fully before deposition, to 
be followed by deoxidation through the agency of organic matter, as has been shown by Dawson to be true of the 
mud now being deposited in the Gulf of St. Lawrence? In either case, the conditions which produced difference 
in color between the lower and upper portions of the clay remain to be explained. The anomalous section 
shown in Fig. 38 adds to the difficulty of this question. 


156 SURFACE GEOLOGY. 


formation of these deposits to the same causes which produced the 
kames. The ice-sheet still remained unmelted upon each side at the time 
of their deposition, filling the valleys and wide areas of low land, over 
which this gravel and sand must otherwise have been spread by the cur- 
rent of the floods on which they were brought. 

The most extensive of these plains occur about Willand and Barbadoes 
ponds, near Dover, and in Newington and the north-west part of Ports- 
mouth. Broadly rounded deposits of the same class occur frequently in 
this district ; and southward, along the sea-coast, they form the elevations 
on which the villages of Rye, North Hampton, and Hampton are built. A 
very interesting ridge of this kind extends from north-west to south-east 
through Newburyport. 

Willand pond* is situated principally in Somersworth, two and a half 
miles from the city hall in Dover. Its area is 84 acres, and its height 
above low tide in the Cochecho is 192 feet, as determined by survey of 
Hon. James A. Weston and Joseph B. Sawyer, made in 1871, in reference 
to supplying the city of Dover with water.| Their report says of this 
pond: 

“It has no visible inlet worthy of consideration, and at ordinary 
stages it has no visible outlet. The ordinary annual high-water mark 
was about two feet above its surface at the time the survey was made. 
It appears that when the pond reaches this height, the surplus water, if 
any there be, runs off through a piece of low, wet, bushy ground (called a 
heath), of some I0 to I5 acres in extent, which lies on the northern bor- 
der of the pond—the water finally escaping through a slight artificial 
channel or ditch into a brook, which is tributary to the Salmon Falls 
river. 

“On all other sides the pond is bounded by a dry, gravelly plain, which 
is from 12 to 17 feet above low water, and which extends from a quarter 
to a half mile from the pond. This plain is bounded in most directions 
by lower plains and valleys having a retentive clayey soil, which, being 
lower than the surface of the pond, contribute nothing to its waters. 


* The plain about this pond, and the kame which extends thence to the south, are shown on Plate VI, p. 146. 

+ Other heights in Dover, measured in this survey, are the following, stated in feet above low tide in Cochecho 
river: Lower step of front door of city hall, 45; do. of American House, 73; summit on Franklin st., near Dr. 
Horne’s, 86; corner of Locust and Silver sts., 98; first floor of Belknap school-house, 123; threshold of tool-house 
at Pine Hill cemetery, 152; highest point on Garrison hill, 297. 


MODIFIED DRIFT IN PISCATAQUA BASIN. 157 


“On the contrary, there are several large springs on the borders of the 
lower plains, which are supplied from the body of sand constituting the 
plain above, and probably in some instances from the pond itself. On 
the side next the city the springs are about 41 feet lower than the pond, 
and are of such size that they supply the water for the Cochecho Aque- 
duct Co. It is probable that these springs are subterranean outlets for 
the water of the pond, and undoubtedly these and all the others drain 
some portions of the sandy plain surrounding the pond. = * 

“How extensive the area is which furnishes water to the pond we have 
no reliable means of determining, because the water-courses and divides 
are hidden beneath the surface. It may be stated in a general way that 
the wells sunk into this plain indicate that the water-table rises towards 
the north and west, and falls towards the south and east.” 

In 1876 a water-pipe was laid from this pond to Dover, for which a 
ditch was dug 25 feet deep for a quarter of a mile through the bordering 
plain. This ditch (Fig. 39) showed 
the plain to consist of interstrati- 
fied gravel and sand, the former pre- 


dominating, and containing abundant 


Fig. 39.—SECTION OF PLAIN AT WIL- 


LAND POND, SOMERSWORTH. 
a half in diameter. The whole ap- Depth, 25 feet. 


pebbles, of all sizes up to a foot and 


pearance is kame-like, but the materials are nearly level in stratification. 
The layers of sand were from a few inches to two feet in thickness, but 
were short, not being apparently continuous over large areas. At some 
points only the coarse gravel was found, with no clear sand. No boulders 
were seen on the surface or in the excavation. 

This plain about Willand pond is the highest land between Salmon 
Falls and Cochecho rivers, the descent to which is over uneven areas of 
ledge or till, The shores of the pond on all sides rise steeply to the level 
of the plain. Much of this escarpment appears to have resulted from the 
undermining action of waves. In other portions the gravel and sand were 
deposited with this slope, which, near the point where water is taken for 
the city of Dover, continues to a depth of 60 feet below the surface of the 
pond at ten rods from its shore. At that time the hollow which is now 
filled by the pond, and the wide valleys to the east and west, appear to 
have been occupied by portions of the departing ice-sheet. 


158 SURFACE GEOLOGY. 


On the south this plain descends 25 to 50 feet in an escarpment, below 
which the edge of the gravel and sand is overlain by a peculiar clayey 
stratum, which extends with an undulating or nearly level surface south- 
easterly to Garrison hill, and is also well shown south-west from Dover, 
between the city and Bellamy river. Its margin reaches 125 to 150 feet 
above the sea, and is marked by numerous springs. This deposit resem- 
bles the gray clay of the brick-yards in its color; its usually obscure 
stratification, which is, however, sometimes distinctly shown; its occa- 
sional division into small fragments, stained with iron-rust; and its con- 
taining infrequent pebbles from two or three inches to a foot in diameter, 
Except these isolated pebbles it is wholly a fine, clayey silt. On any 
exposed bank it is marked by many little channels, which have been 
formed by the rains, and are preserved through dry weather by the hard- 
ening of the surface. 

The kame-like gravel of Willand pond extends three miles northward, 
to Cole’s pond and the alluvial area of Salmon Falls river, near the east 
corner of Rochester. Southward it is narrowed to an ordinary kame, 
which is cut through by Cochecho river a quarter of a mile above the city 
of Dover. A very instructive section of it is shown by a railroad cut on 
the north side of this river (Fig. 40). The kame consists of gravel and 


Fig. 40.—SECTION OF KaME ON DOVER & WINNIPISEOGEE RAILROAD, 4 MILE NORTH- 
WEST FROM DOVER STATION. Length, 300 feet; height, 40 feet. 


The base of the section is about 40 feet above Cochecho river, or 75 feet above the 


sea. 
a, a, gray clay; b, fine sand; c, c, coarse gravel containing pebbles from 6 inches 


to 14 feet in diameter; d, d, fine gravel. 

sand, and is overlain on both sides by the widely spread gray clay. Nu- 
merous angular boulders, 2 to 5 feet in diameter, had been stranded on 
the north-west side of the kame before the deposition of the clay. An 
excavation between this section and the river exposed a boulder 8 feet in 
its greatest diameter and weighing 16 tons, with another two thirds as 
large, which were embedded in the kame. 


MODIFIED DRIFT IN PISCATAQUA BASIN. 159 


In the west part of the city this kame consists almost wholly of sand, 
and extends in a broad 


etery, being in some 

Fig. 41.—SAND OVERLAIN By TILL, FourTH STREET, 
WEST OF COCHECHO RIVER, DOVER. 

Length of section, 250 feet; height, 30 feet; base of but more frequently by 

section is about 75 feet above the sea. 


places overlain by till, 


gray clay. On the south 
side of Fourth street an excavation (Fig. 41) shows it to be horizontal 
in stratification, except at its sides, where it is obliquely bedded, con- 
formably to its slope. Here its west side is overlain by the unstratified 
upper till, in which are numerous angular boulders 2 to 4 feet in diameter. 
This till also forms a layer two feet thick over the top of the sand, con- 
taining frequent rock-fragments of smaller size. Another section, show- 
ing 15 feet of irregularly bedded sand, overlain by a similar deposit of 
upper till, was observed a quarter of a mile farther south, at a height of 
about 140 feet above the sea. At these points it seems probable that the 
sand was deposited in an open glacial channel, bordered by overhanging 
walls of ice, from which the upper till fell upon the side and was partly 
strewn upon the surface of the kame. 

A ditch for laying water-pipe on Silver street showed this sand deposit 
overlain by gray clay (Figs. 42, 43, and 44). The junction of the sand 


Ridges of till overlain by sand, which is overlain by gray clay. 


Fig. 42.—SECTION ALONG SILVER STREET, SOUTH OF RIDING PARK, DOVER. 
200 feet long; 6 to 9 feet deep. 


and clay was by a gradual transi- Gray Clay overlying. sand. 


tion, occupying one or two feet, 
and three or four feet of the clay 


Fig. 43.—Same, 300 feet east of last; 100 feet 
next above was plainly stratified. long; 8 to 10 feet deep. 


The rest of the clay was very 
compact, with no evident lamina- 


tion, breaking into iron-stained, 


Gray clay overlying sand, which overlies till. 


angular pieces, and contained oc- Fig. 44.—Same, 500 feet farther east; 100 feet 
casional pebbles. In the midst pO ERE Pe oe ECHL SE 


of this clay (Fig. 43) a horizontal sandy layer was very distinctly shown 


160 SURFACE GEOLOGY. 


for a distance of 150 feet. Near its east ‘end, iron-stained gravel and sev- 
eral stones a foot in diameter were found between the clay and the west 
edge of the underlying sand. 

Eastward, these deposits lie in a kame-like ridge, a section of which 
(Fig. 45) shows one side of it to be wholly gray clay, while the other side 


Gray clay, its lower portion Silver street, ‘i 
i Uistingtly stented, bridge over R. R. Sand overlain by gray clay. 


8 eS SSS 


Fig. 45.—EXCAVATION FOR THE PORTSMOUTH & DOVER RAILROAD, 1000 
FEET EAST FROM FIG. 44. 


Length, about 500 feet; depth, 20 feet; top of section is about 100 feet 
above the sea. 

is mainly sand; but their junction is concealed by the abutments of a 
bridge. The outer edge of the sand, however, is overlain by similar clay. 
Pine Hill cemetery, a half mile farther south-east, is a level plain of 
horizontally stratified sand, 150 feet above the sea., It is bounded on the 
north and west by escarpments, which descend steeply 30 feet. The dep- 
osition of this sand appears to have been confined here by walls of ice. 
On the south-east are ledgy hills which are somewhat higher, in whose 
hollows are low mounds or ridges of gravel and sand, one of which was 
observed to contain masses of till, one to three feet thick, full of angular 
boulders up to two feet in diameter (Fig. 46). These materials probably 
fell from the glacier upon the margin of 


ice at its foot, and when this was broken 
up, they were floated away on rafts, which 


; at length melted, dropping their freight 
Big. 46—“Secti0n N 4 FAME to be thus embedded in modified drift 
CEMETERY, DOVER. The pebbles which we have mentioned as 
Scale, 1 inch=1o feet. . occurring here and there in the gray clay, 
were distributed in the same manner. This clay and its pebbles were 
deposited at a later date, following the withdrawal of the ice-sheet by 
which the earlier gravel and sand were confined in these kame-like plains. 
The sea in this period stood at a higher level than now; and the 
clay was probably a marine deposit brought down from the melting ice- 
sheet at the north-west. It is well shown in Dover, Madbury, Durham, 


and Newington, forming the surface of much of these towns, but not 


MODIFIED DRIFT IN PISCATAQUA BASIN, 161 


observed at a greater height than about 150 feet above the sea. On the 
borders of Great bay and Piscataqua river it seems not to exceed a height 
of 50 feet. A well near the Boston & Maine Railroad, about a mile west 
from Dover, passed through 20 feet of this compact, pebbly gray clay, 
below which was a water-bearing stratum of sand. A neighboring well 
showed Io feet of similar gray clay; then 2 inches of clear sand; beyond 
which this clay continued 16 feet lower, and was underlain by 14 feet of 
mud, apparently containing sticks and leaves, and lying upon ledge. 

At the county farm, three miles north-west from Dover, and about 
150 feet above the sea, a well showed 50 feet of this clay; which con- 
tained sandy layers, but otherwise was obscured in its stratification. 
Stones were frequently found, the largest of them weighing about 100 
pounds. Below this was a stratum of gravel and sand, which seemed 
“like the bed of a stream,” and yielded an abundance of water. This 
deposit lies upon till, which is exposed at forty rods to the north. On 
the west side of Cochecho river, at a bridge slightly farther distant to 
the north-west, is a kame that probably marks the mouth of the glacial 
river by which this marine delta was formed.* 

Barbadoes pond, crossed by the line between Dover and Madbury, is 
surrounded by an elevated plain of gravel and sand,f about 175 feet above 
the sea, of the same kame-like origin with that about Willand pond. This 
plain is bounded by an escarpment 10 to 40 feet high. At its foot on the 
south-east are springs which supply the west part of the city of Dover. 

Southward we find other extensive deposits of the same origin. On 
the south side of Bellamy river, for a mile and a half east from Madbury 
station, is a broad ridge of coarse water-worn gravel and sand of about 
the same height with the plain at Barbadoes pond, and 50 feet higher 
than the adjoining land, on any side. One mile south from Sawyer’s 
mills in Dover, and in the same line with the foregoing, is a similar ridge 
two thirds of a mile long and about 150 feet above the sea. The ridge, 
about 125 feet in height, between Bellamy and Piscataqua rivers at one 
to two miles north from Dover point, is shown by wells to be the same 


* A recent journey has brought to our notice an alluvial plain on the west side of the Cochecho, opposite to 
and lower than this delta. It was probably flaviatile, belonging to a later date when the ocean held a lower level. 
The rounded delta and the imperceptibly sloping plain show the contrast between deposition in deep and quiet 
water, as of a lake or arm of the sea, and that which takes place from the shallow floods of rivers. 

+ The extent of this deposit, and of others described at the south-east, may be seen on Plate VI 


VOL, III, 21 


> P. 146, 


162 SURFACE GEOLOGY. 


interstratified gravel and sand. In this class, also, are, a ridge noted at 
the west line of Durham, half a mile south-west from Oyster river; the 
deposit, shown in Fig. 47, 

cut by the Nashua & Roch- S- 


ester Railroad at the divide _. 
Fig. 47.—SECTION IN SAND NEAR WHEELWRIGHT 
between Oyster and Lam- Ponp, LEE. 


prey rivers; the gravel plain Height, 30 feet. Base of section is about 150 feet 
of Lee Hill village, 190 feet above: SNe Bems 
above the sea; and the plain of nearly the same height, two miles west 
from Newmarket, on the road to Wadley’s Falls, composed of coarse 
gravel at the west, but of clear sand to a depth of 30 feet in its eastern 
portion. 

One of these deposits near Newmarket Junction, composed mainly of 
sand with no rocks embedded in it, has its surface strewn with angular 


Fig. 48.—SEcTION oN Boston & MAINE RAILROAD, } MILE 
NORTH OF NEWMARKET JUNCTION. 


Length, about 600 feet; height, 35 feet. Base of section is 
about 50 feet above the sea. 


boulders, the largest of which are 10 feet in their greatest diameter, weigh- 
ing 30 or 40 tons. The sand was deposited in the channel of a glacial 
river. When the ice on both sides and beneath it melted, this fell to the 
bottom of the shallow sea, which probably stood 150 feet above its pres- 
ent height. The boulders were then dropped on its surface by blocks or 
rafts of floating ice. 

The academy in Greenland is built on a broadly rounded, kame-like 
ridge of gravel, which at a short distance to the south-west becomes a 
nearly level plain 40 or 50 rods wide, but still farther to the south-west 
is narrowed to a typical kame. The length of this deposit is a half mile. 
Its height is nearly 100 feet above the sea. 

At a school-house half a mile south from the academy, we rise to a 
plain about 125 feet above the sea, which extends a mile to the south and 
south-east, descending with a gentle slope 25 to 40 feet in that distance. 
This plain forms the highest land between Winnicut river and Berry’s 


MODIFIED DRIFT IN PISCATAQUA BASIN. 163 


brook. Its north-west portion is quite thickly strewn with boulders, the 
largest of which are 5 or 6 feet in diameter; and over nearly its whole 
extent these have been sufficiently abundant for walling the fields. Four 
wells, however, between the school-house and the Eastern depot, varying 
from 20 to 30 feet in depth, passed all the way through stratified gravel, 
sand, and blue clay. In three of these wells the upper portion was fine 
gravel or sand. One of them, a half mile south-east, and a cistern a 
quarter of a mile south from the school-house, showed at the top 10 feet 
of very coarse but water-worn gravel, which was underlain by clear sand. 

Two thirds of a mile farther east, beyond the railroad and Berry's 
brook, a well at the house of L. & F. A. Berry (county map) encountered 
10 feet of coarse gravel, below which were interstratified fine gravel, 
sand, and blue clay, extending 16 feet to ledge. Mussel shells which 
still retained their purple color, but were easily broken in pieces, were 
found in this well eighteen feet below the surface. Three fourths of a 
mile south from the school-house, a well at N. Norton’s (county map) 
passed through 40 feet of coarse gravel containing pebbles up to 5 or 10 
inches in diameter, with layers of sand. Ata depth of about 25 feet in 
this well several white pine cones were found, and about 5 feet lower 
numerous mussel shells, both being well preserved and distinct. The 
two last wells are one and a quarter miles apart, each being at the surface 
about 100 feet above the sea. 

The very thin covering of till and frequent scattered boulders which 
lie on the north-west portion of this plain, were probably in large part 
distributed by floating ice; but this appears to have taken place at a time 
when the ice-sheet paused in its retreat, and once more overspread areas 
from which it had withdrawn, Evidence of a reddvance of the ice-sheet 
was also afforded by a well in Stratham, a third of a mile east of Barker's 
hill. Here the surface was 5 feet of upper till, which also extended fully 
twenty rods on every side, containing boulders up to 6 or 8 feet in diam- 
eter, underlain by 21 feet of sand and fine gravel, the bottom of which 
was not reached. A hill in the north-west corner of North Hampton, 
which rises 75 to 100 feet above the lowland by which it is entirely sur- 
rounded, or about 150 feet above the sea, is covered to the top on its: 
north side with very coarse glacial drift,.containing abundant angular 
boulders of all sizes up to 10 feet in diameter; yet this hill is shown by 


164 SURFACE GEOLOGY. 


wells to be principally composed of modified drift, a large part of which 
is clay.* On its south side the surface is gravel, with few boulders, none 
of which exceed 4 or 5 feet in diameter. 

The last of these kame-like deposits which remains to be described 
within the limits of Piscataqua basin, is the extensive plain of Newington 
and the north-west part of Portsmouth. This is three miles long from 
north to south, and for most of this distance averages a mile in width, 
forming a plateau 60 to 100 feet above Great bay and Piscataqua river 
on each side. Outcropping ledges and scattered boulders are seen in 
many places upon its surface; but numerous wells show only modified 
drift to depths of 30 or 40 feet, being first coarse gravel, 3 to ro feet in 
thickness, succeeded below by interstratified fine gravel and sand. The 
entire western edge of this deposit is a gently sloping escarpment, which 
descends Io to 30 feet. On the north and east it rests mainly on ledges, 
but at one place falls in an abrupt slope more than 50 feet. A section 
at its base in the north part of Newington showed sand overlain by gray 
clay, as at Dover. Southward, near the Concord & Portsmouth Railroad, 
its surface is sand, obliquely stratified. Between this and the Eastern 
Railroad it is changed to a broad ridge, 25 to 30 feet high, composed 
mostly of pebbles six inches to a foot in diameter, packed as compactly 
as possible with no layers of sand. This gravel is finely exposed in an 
excavation, from which it is teamed two miles for repairing streets in 
Portsmouth. The deposit terminates south-east from the Eastern Rail- 
road in a small plain of horizontally stratified sand. 

Exeter River and the Plains at Kingston and southward. The prin- 
cipal part of Exeter village, and several square miles bordering Exeter 


* The following are sections of wells upon this hill, noted in order from north-west to south-east : 

1. A well dug three years ago at C. C. Barton’s, about 30 feet below the top of the hill, showed till on the sur- 
face, 4 feet; gray clay, plainly stratified and sandy in some layers, but containing occasional pebbles seldom 
more than 6 inches in diameter, 38 feet; clear sand, with water, 1 foot; blue clay, 9 feet, extending lower ;—total 
depth, 52 feet. 

2. The former well here, about 150 feet distant to the south-west and nearly the same in height, was through 
till, 4 feet; gray clay, as in new well, 4 feet; sand and fine gravel, 15 feet; gray clay, 27 feet;—total depth, 50 
feet. The last eight feet were bored, and at the bottom the auger “ fell,’’ and a powerful flow of water came up. 

3. At A. Wiggin’s, near the top of the hill, a well 52 feet deep through unknown material becomes dry in sum- 
mer, and was recently bored 12 feet lower through sand without striking ledge ;—total depth, 64 feet. 

4. At E. F. Wiggin’s, perhaps 30 feet below the last place, the order was till containing boulders up to 500 pounds 
in weight, with layers of gravel and sand, 20 feet; interstratified fine gravel, sand, and clay, 20 feet; very com- 
pact gray clay, nearly free from rock fragments, 16 feet, underlain by quicksand with abundant water ;—total 
depth, 56 feet. 

5. A well dug two years ago at T. E. Marston’s, about 20 feet lower than the last, passed through coarse water- 
worn gravel, with the largest stones 1} feet in diameter, 8 feet; sand and fine gravel, 10 feet; gray clay, stratified 
and containing layers of sand, 20 feet ;—total depth, 38 feet. 


MODIFIED DRIFT IN PISCATAQUA BASIN. 165 


river on the south and extending into Kensington, are alluvial sand and 
gray clay, 30 to 60 feet above the sea. 

A map on Plate VI (p. 146) shows the belt of plains which extends 
south from this river to the Merrimack at Haverhill, Mass. At the 
north line of Kingston their height is about the same as that of Spruce 
swamp in the east part of Fremont, which is shown by the survey for 
the Nashua & Rochester Railroad to be 160 feet above the sea, or about 
30 feet above Exeter river. Half of the township of Kingston is occu- 
pied by these sandy plains, which slope to a height of 125 feet above the 
sea at its south line. Numerous ponds, which are the sources of Powow 
river, mark where portions of the ice-sheet remained unmelted while 
the deposition of modified drift went on rapidly at each side. A large 
area of kames is indicated on the map in the northern part of Plaistow. 
Their southern portion consists of the ordinary water-worn gravel in 
short, steep ridges and mounds. At the north and north-west, these pass 
gradually into very coarse morainic débris, coritaining angular blocks of 
all sizes up to 10 feet in diameter, much of which is accumulated in low 
ridges like those of the kames. In Plaistow the plains continue their 
slope to about go feet above the sea. In Haverhill a large portion of the 
original deposit has been excavated by Little river; and its south end 
has been partly undermined by the Merrimack, on whose north side it 
forms a conspicuous terrace west of the railroad bridge. 

Fossils. Although it seems probable that the sea stood about 150 feet 
higher than now during the deposition of most of the modified drift in 
this basin, only very scanty relics of the life of this period have been 
found. A whale’s vertebra, now in the museum of Dartmouth college, 
was discovered in Somersworth in 1843 by the caving in of a gravel bank, 
but no other bones were found. Several wells in the village of South 
Berwick show marine remains at a depth of about 30 feet in a stratum 
of fetid mud, which resembles that of the tide-flats, and frequently ren- 
ders the water unfit for use, at least through a part of the year. The 
humerus, radius, and ulna of a seal, and shells of Mucula Portlandica 
(see foot-note on next page), are mentioned by Jackson from wells at this 
place, which are about 100 feet above the sea, the fossiliferous stratum 
having a height of about 70 feet. The surface here was three feet of 
_ sand, the whole depth below which was clay, the upper portion gray and 


166 SURFACE GEOLOGY. 


the lower blue. A third of a mile to the south, near the landing, two 
wells at about 50 feet above the sea show 20 feet of gray and 10 feet of 
blue clay, succeeded by a layer of fetid mud with numerous clam and 
mussel shells 30 feet below the surface, or only 20 feet above the sea, 
Casts of clam and mussel shells were found in a brick-yard worked 
twenty years ago on the shores of Bellamy river, a half mile north-west 
from Dover point. They also occur in the brick-clay of Eliot on the east 
side of the Piscataqua. 

Shells* of Saxicava rugosa, Mytilus edulis, Sanguinolaria, and Astarte 
castanea were found at several places in Kittery within 30 feet above the 
sea by Mr. John L. Hayes. He also discovered Mucula Portlandica* and 
Sanguinolaria* in Portsmouth near Wibird’s hill. The shells at this place 
were 15 feet below the surface and 30 feet above high tide, in blue plas- 
tic clay. Mussel shells are reported at two localities in Greenland (p. 
163); but farther to the south no fossils appear to have been discovered 
within the limits of this state, although there is considerable modified 
drift which was probably deposited beneath the sea. The shells found 
in Portsmouth and South Berwick show that an arctic climate prevailed 
during the deposition of the beds in which they occur; but the presence 


* Jackson’s Final Report on Geology of New Hampshire, pp. 94, 121, and 281. 

The shells here mentioned are all species now living. One of them is confined to arctic seas; of the rest, all 
but one are circumpolar, extending south to our latitude, while one has its northern limit at Nova Scotia, and is 
most abundant southward. Their synonyms and range, fossil and living, are as follows : 

Nucula Portlandica, Hitchcock; Leda truncata, Brown; Leda arctica and Portlandia glasialis, Gray ; 
Yoldia arctica, Sars (but not of Méller and Mérch). This shell gives its name to the Leda clay of Canada. Fos- 
sil in New Hampshire, Maine, New Brunswick, Province of Quebec, Labrador, Norway, and Scotland. Ports- 
mouth, N. H., is the most southern locality at which it has been found. Now living only in arctic seas; found 
at Spitzbergen in depths from five to thirty fathoms. 

Saxtcava rugosa, Linn.; S. arctica, Deshays. Variable, having been described under five genera and fifteen 
species. This shell gives its name to the Saxicava sand of Canada. Fossil from New England to Labrador and 
in Europe; var. distorta, Say, is found in the Miocene of Maryland. Now living in arctic seas, and abundant 
southward to Cape Cod, and less common to Georgia; also extending south to the same latitude on the Pacific 
coast of America and in Europe. It occurs from low-water mark to a depth of fifty fathoms. 

Mytilus edulis, Linn. Common mussel. Fossil from New England to Greenland and in Europe. Now living 
in arctic seas, extending south in the Atlantic to North Carolina and the Mediterranean sea, in the Pacific to 
China and San Francisco. Littoral to fifty fathoms. 

Sanguinolarvia (obsolete); Macoma, Leach. Two species of this genus, Macoma Grenlandica, Beck(M. /ra- 
gilis, Adams), and Macoma sabulosa, Mirch (Mf. calcarea, Adams), are common as fossils from New England to 
Labrador and Greenland, and the latter also in Europe. Both are now living on our coast from the Arctic ocean 
to Long Island; the latter is also found in northern Europe, and extends south on the coast of Asia to Japan. 

Astarte castanea, Say. Fossil at Nantucket and Point Shirley, Mass., and at Kittery, Me. Now living from 
New Jersey to Nova Scotia; common as far north as Massachusetts bay. Abundant in Provincetown harbor at 
low-water mark, but more frequently occurring at depths from five to fifteen fathoms. 

Mya arenaria, Linn. Long clam; the common clam of our coast north from Cape Cod. (Venus mercenaria, 
the round clam, or quahog, is the common species south from New York.) Fossil from South Carolina to Green- 
land, in Europe, and in the Miocene of Virginia. Now living from the Arctic ocean to South Carolina,—very 
abundant as far south as New Jersey; also extending south to France and China. Between high and low tide, 
and thence to forty fathoms. 


ANDOVER AND HAVERHILL SERIES OF KAMES. 167 


of Astarte castanea at Kittery is proof that the ocean became as warm 


as now before it sank to its present level. 


KaMEs IN THE SoutH Part oF RocxincHaM CounTy anp IN Nortu- 
Drees 
EASTERN MASSACHUSETTS. 


This district contains very interesting and instructive series of kames, 
which differ from those described along the Connecticut and Merrimack 
rivers, and in the basin of Ossipee lake. It will be remembered that 
those series lie along the middle and lowest portion of valleys. The 
series of kames now to be considered do not follow the present water- 
courses, but run directly across the Merrimack and other rivers, which 
here have no well marked valleys, being not much lower than the hollows 
between the hills on either side. Occupying these hollows or lying 
against the side of the hills, the kames extend long distances in a some- 
what devious, but for the whole series, quite straight course, which is 
about half-way between south and south-east. 

Rev. George F. Wright, of Andover, Mass., has given much attention 
to the surface geology of this district, and has kindly supplied the follow- 
ing description of these kames: * 


A formation of gravel, known at Andover as ‘Indian Ridge,” has long been familiar 
to the citizens, and has been remarked upon frequently by tourists and geologists. We 
could not improve the description of the main features of similar formations given 
by Dr. Edward Hitchcock in 1842. He writes,—‘‘ Our moraines form ridges and hills 
of almost every possible shape. It is not common to find straight ridges for a consid- 
erable distance. But the most common and most remarkable aspect assumed by these 
elevations is that of a collection of tortuous ridges and rounded and even conical hills, 
with corresponding depressions between them. These depressions are ,not valleys 
which might have been produced by running water, but mere holes, not unfrequently 
occupied by a pond.” 

By reference to Map 1, Plate IV, the characteristics of this formation may easily be 
apprehended. At the flax mills near Andover depot, a dam raises the Shawshin river 
14 feet. Measuring from the river-bed below the dam, the ascent to the peat-bog, o, 
at the base of the east ridge, is 41 feet. Taking this bog as a level, the heights of the 
successive ridges,—East ridge, Indian, and West,—at the points a, 4, and eu, are 41 feet, 
49 feet, and 71 feet. The point c, however, is in a characteristic depression of the 


* For some further particulars and facts bearing on the origin of these series of kames, see a paper by Rev. Mr. 
Wright in Proceedings of the Boston Society of Natural History, vol. xix, pp. 47-63. 


+ Transactions of the Association of American Geologists and Naturalists. 


168 SURFACE GEOLOGY. 


ridge. On either side of it, north and south, prominences project 20 feet higher, mak- 
ing them 91 feet above the base assumed at 9, and 132 feet above the river, or 182 feet 
above the sea. 

Branches not adequately indicated on the map run off at various points and form 
enclosed basins, which have no outlet except as channels have been cut through the 
loose material of the ridges, either by natural or artificial means. Quite an extensive 
body of water was included, till long after the settlement of the town, in an enclosure 
between 4 and ¢. It has been drained, partly by a channel of its own formation and 
partly by artificial means, and is now occupied by a muck swamp, which is 20 or 30 
feet deep. A trigonometrical section of the west ridge, near the point c, gives the 
height above this swamp 61 feet, with a base of 250 feet. The rate of descent from 
the apex at this point to the base is therefore one foot in two. 

A few rods east of the point o there are irregular remnants of ridges of the same 
general character with the others, running south-east across the Shawshin river and 
Boston & Maine Railroad. East of this railroad it is apparently pushed into a great 
number of irregular prominences enclosing numerous bowl-shaped basins, one of which, 
of oblong shape and about fifteen feet deep, is at the very summit, the rim of which 
rises to a height of about 100 feet above the river. A mile south, at Pomp’s pond, and 
partially connected by intervening ridges, is a similar cluster of rounded hills and en- 
closed basins, surmounted by a sharp peak of still greater height. 

We should also observe that clusters, or ganglions, of such irregular ridges, encircling 
bowl-like reservoirs and rising into sharp peaks, occur at frequent intervals along the 
whole belt of the formation we are describing. Frequently, as a ridge is suddenly 
pushed up into a pinnacle, it will put out a spur, returning to itself and forming a 
closed basin at or near its top. 

These ridges are ordinarily composed of sand, gravel, and pebbles, the latter from a 
few inches to two or three feet through, sometimes irregularly stratified, the coarse 
material being as likely to abound near the top as at the bottom; at other times, Io or 
15 feet or more in thickness will give no signs of stratification whatever. The top of 
the ridge is usually just wide enough for a foot-path; and pebbles a foot or two in 
diameter dot its course at frequent intervals. Usually, also, the base of the ridge is 
partially hid by subsequent accumulation of stratified sand and fine gravel, or by peat- 
bogs. 

Another point of importance is, that the fragments of rock in the ridges are nearly 
all somewhat rounded and apparently water-worn, though it is evident that they have 
not all been subjected to the same amount of attrition. I have searched in vain among 
the débris of the formation for scratched stones, though striated stones are found in 
abundance near the surface in the immediate vicinity. Furthermore, the pebbles are 
not of local origin. Merrimack slate abounds, as does a porphyritic gneiss, whose po- 
sition is well determined in central New Hampshire. In Topsfield, a portion of the 
pebbles are clearly from ledges only a few miles to the north-west. 

The formation does not lie ata uniform altitude above the sea, but rises over hills 


Plate VII. 


laps of the 


ANDOVER AND HAVERHILL 


Stansetsen 


SERIES OF KAMES. 
By Rev. Georce F, Wricut. 


R 
Maty, 


s 
ay, 2 
ae 
PATA ie 
Sie SS 


west 
ih 


Pl a 


= 
2. °/ WILMINGTON. 


oe,’ 
4 ve 
Pad ee 


a ‘ly i ‘ 2, / 


Miles. 


Taz 


1 


Ww 


A 


k 
\ 
y 
? 
0 
x 


TEWwKSBUAY af 
Ae \ / 
ILMINST OH = 


5 


SALEM ¢ 
‘a. Lied 


Ny. PEABODY = 
bs Be A 
= act P 


f 


EN 


Nt 


OWN 


ya) : 


HELIOTYPE 


ANDOVER AND HAVERHILL SERIES OF KAMES. 169 


and descends into river valleys in a certain apparent independence of the natural con- 
figuration of the country. The land, however, though undulating and somewhat 
broken, nowhere in this part of Massachusetts rises more than 300 or 400 feet above 
tide-water ; and even these heights are reached only by peculiar accumulations of un- 
modified drift or till, which here forms massive rounded hills. The gravel ridges 
plainly belong to the superficial deposit, since they everywhere overlie the ground- 
moraine or till. They rest upon the flanks of these hills at Lawrence near the reser- 
voir; at Ballard Vale, on Pole hill; at Wakefield, near the rattan works; in the north- 
east part of Middleton; and on the north bank of the Merrimack in Haverhill, opposite 
to and a little below Groveland. 

Sometimes the ridges disappear in a sandy plain, in which case, however, there are 
usually bowl-shaped depressions in the plain along the line of general direction. This 
is noticeable east of Ballard Vale. These depressions are frequent in Kingston, N. H., 
near Great pond. But the most remarkable instance is near the cemetery in Marple- 
head, a half mile south-east from the lead mills in Salem. Here is a cluster of depres- 
sions within a depression. The outer rim has a north-to-south diameter of 605 feet, 
and an east-to-west diameter of 735 feet. A hollow at the south side descends to the 
tide-level, with a depth of 60 feet and an east-to-west diameter at the top of 360 feet. 
A similar though shallower hollow occurs at the north-west side. Numerous minor 
depressions intervene. The material of these circular ridges is partly of local origin, 
and partly not. Plant them upon higher ground, and they would be called the reticu- 
lated portion of akame. Many lakelets are but these depressions full of water. 

These ridges have been found in two well defined series, as shown in Map 3, Plate 
VII. The westernmost or Andover series may be represented in Rockingham county 
by kames observed near the Manchester & Lawrence Railroad, north-west from Wil- 
son’s crossing in Londonderry, near West Derry station, and at a point a mile and a 
half farther south on the west side of the railroad; also near Goss pond in the south- 
east part of Londonderry, where there are bowl-shaped depressions, and thence south- 
ward to West Windham station on the Nashua & Rochester Railroad; also near a 
granite quarry a half mile west from Salem Depot. 

In Massachusetts this series extends through Methuen, Lawrence, Andover, North 
Reading, Reading, Lynnfield, Wakefield, and Melrose, terminating near the south end 
of Prospect hill in Malden. It is continuous from Messer’s crossing and Mystic pond 
in Methuen to the pumping-station of the Lawrence water-works, being well shown on 
the hillside south-east of the reservoir. On the low land near Spicket river these 
ridges show stratification ; but higher up, as north-west of the Catholic cemetery, they 
are for the most part unstratified. Bowl-shaped depressions abound. 

This series is finely developed near Andover, as shown in Maps 1 and 2, forming the 
banks of Pomp’s, Foster’s, and Martin’s ponds. Numerous sections of these ridges 
show the central portion unstratified, the pebbles of large size being in and resting on 
the clay, loam, and unwashed sand; but sometimes we find stratified material under 


an unstratified mass, or pockets of partly stratified material in the unstratified. 
VOL. III, 22 


170 SURFACE GEOLOGY. 


In North Reading and Reading this series winds its way through extensive swamps, 
intersected by Ipswich river; in Wakefield much of its material has been removed by 
human agencies; in Melrose it is characterized by a plain with depressions. Its length 
in Massachusetts is about twenty-five miles. 

The Haverhill series of kames is nearly parallel with the preceding, and about seven 
miles distant. It appears in the north-east part of Auburn, near Eaton’s mills; in 
Chester, near Asa Wilson’s; in Sandown, with extensive sandy plains and numerous 
ponds; and in East Hampstead, where the ridges are well defined, extending to the 
west side of Mt. Misery at the north line of Plaistow. A mile south-east from Mt. 
Misery the kames occupy a large area, and are thence continuous through Plaistow and 
the east part of Haverhill. They are well shown in Haverhill, near the old Whittier 
house; near the East Parish church; and near Burns’s mill. At the Whittier house 
they seem to have been composed of coarse pebbles in contact with each other, sind 
hayjng subsequently sifted into the interstices. 

In Groveland they are partly covered with alluvium north of the depot. Rock pond 
in Georgetown is bordered by a spur of this series, and divisions of it extend south 
from both sides of Bald Pate hill. Wood pond and Four-mile pond in Boxford, Pritch- 
ard’s pond in Ipswich and Topsfield, and Muddy pond, Cedar pond, and Wenham 
lake in Wenham and Beverly, are surrounded by these deposits, which extend nearly 
to Beverly Cove. This series is not less than forty miles in extent. 

Between the southern portions of these series of kames an intermediate one appears 
in Map 3, running from Topsfield with some interruptions to the depressions, or ‘‘dun- 
geons,” which we have described in Marblehead. Near Danversport these kames are 
stratified, but farther north two or three fresh sections show no stratification. 

Kames also occur in a series still farther to the east, though perhaps less closely con- 
nected with one another than the foregoing. They are well developed in the west part 
of Spruce swamp in Fremont, where one of these ridges is occupied by a road. Kames 
and bowl-shaped depressions border Great and Country ponds in Kingston. In the 
east part of Newton and the south-west corner of South Hampton a large area is cov- 
ered by reticulated ridges, 20 to 60 feet in height, and containing boulders 2 to 4 feet 
in diameter. The Jong arm of Kimball pond in Amesbury is bordered on its north- 
east side by the continuation of this series, which is here a single ridge of ordinary 
gravel 20 to 40 feet high. 


MopiFieD Drirr ALONG THE SEA-CoastT. 


The oldest and most prominent deposits of modified drift near our 
coast are kame-like hills, elevated plains, and broad ridges, composed of 
gravel, sand, and clay, the description of which is here continued from 
page 164. The gently-sloping hill on which Rye village is situated, 
nearly 100 feet above the sea, is mainly stratified gravel from 25 to 40 


MODIFIED DRIFT ALONG THE SEA-COAST. 171 


feet in depth. It is coarse for the first ten feet, with the largest pebbles 
a foot in diameter; below, it is fine, but has little clear sand.* Breakfast 
hill, about 150 feet above the sea, and the plain about 50 feet lower, which 
extends southward to the first railroad crossing in North Hampton, are 
composed of coarse gravel and sand. Thence similar deposits, 100 to 
125 feet above the sea, extend in nearly level plains south-west to North 
Hampton village, forming the water-shed between Winnicut river and 
the ocean. They are bounded in many places by escarpments which 
descend steeply 25 to 50 feet; and a hollow, about an acre in extent and 
50 feet deep, is half filled by Knowles pond. This formation continues 
southward with nearly the same height to Hampton village, where it ter- 
minates, falling in gentle slopes towards the sea. 

Nine miles farther south, part of the city of Newburyport is built on a 
broadly rounded ridge of gravel and sand, which, like the foregoing de- 
posits, probably had a similar origin with the narrow and steep ridges of 
the kames, having been bounded by portions of the melting ice-sheet. 
The series of kames noticed by Rev. Mr. Wright in Newton and Ames- 
bury may be continuous south-east to the Newburyport ridge. So far 
as traced, this deposit appears first in the south part of Amesbury. It 
has been cut through by Merrimack river, and on its opposite side rises 
to a height of about 150 feet in Moulton’s hill. A quarter of a mile 
farther to the south-east it is depressed to 75 feet, and shows the sharp 
ridges and knolls of typical kames. From this point it extends, with a 
nearly uniform height of about 100 feet, along High street to the middle 
of the city, and thence continues on the south-west side of this street to 
the Upper Green. Here it is interrupted for a little distance, beyond 
which it lies on the north-east side of this street, extending to within a 
half mile of Old Town hill. It is thus at least six miles long. No other 
high deposits of modified drift are found in this vicinity; and wide areas 


* The ch of these deposits will be seen from the following sections of wells, 1 to 1% miles south-west 
from Rye village, on the water-shed south of Berry’s brook, and about 100 feet above the sea; 

2. At J. Philbrick’s (county map), said to be the deepest well in Rye, coarse gravel, 25 feet; sandy, gray clay, 
very compact, free from pebbles, 28 feet ;—total depth, 53 feet. The only rock found in the clay was an angular 
block weighing about 200 pounds, 40 feet below the surface. 

z. Near L. Brown’s, coarse gravel, 8 feet; sand, 8 inches; coarse gravel, 6 ‘feet; very coarse gravel, ro feet, 
much of it composed of rounded rocks of nearly uniform size, about a foot in diameter, with scarcely any earth, 
so that ‘‘one could look down among the pebbles ;”’ ordinary gravel, with layers of sand, 20 feet, resting on 
ledge ;—total depth, 45 feet. 

3. At R. Shapley’s, coarse gravel, ro feet ; fine white sand, rs feet, resting on till or ledge. Several other wells 
in this neighborbood, 30 to 4o feet in depth, encountered nothing but stratified gravel, sand, or clay. 


172 SURFACE GEOLOGY. 


of lowland lie on both sides. Excavations in the north-west part of the 
city show the ridge there to be composed mainly of water-worn gravel, 
with the largest pebbles about a foot in diameter. A railroad cut, known 
as March’s hill, two miles farther south-east, has only occasional layers 
of gravel, with the largest pebbles six inches in diameter, very irregu- 
larly stratified with sand, which is here four fifths of the whole deposit. 
The depth of modified drift forming the ridge is shown by wells to be 
from 50 to 90 feet. 

Portions of Seabrook and Salisbury are sandy plains, 25 to 50 feet 
above the sea. These are probably marine beds, deposited in a consider- 
able depth of water, but they are not known to contain organic remains. 

The most recent deposits of modified drift are the beaches and salt 
marshes bordering the ocean. Along much of our coast, at a distance 
varying from a quarter of a mile to one mile or more beyond the natural 
shore of hard land,—that is, of ledge, till, or ordinary modified drift,—we 
find a beach-ridge of quartzose sand, which becomes gravel or shingle 
near rocky shores. This ridge of loose material has been heaped up by 
the waves nearly to the highest point reached by them at high tide dur- 
ing storms; and when it is composed of sand, the wind piles it still 
higher in irregular hills, mounds, and ridges, which are constantly chang- 
ing inform. The beach-ridge of Plum island, at the mouth of Merrimack 
river, is thus blown into dunes 50 feet high. On the side away from the 
sea, this formation slopes somewhat steeply to the solid bottom, 10 to 40 
feet below the sea-level; towards the sea, it often slopes away very gently, 
with a wide area of hard sand between the lines of high and low tide. 
For a quarter of a mile out from these beaches the water is shallow, and 
the waves break upon shifting banks of sand. 

The area from the beach to where the land rises above the reach of 
the sea is usually occupied by salt marsh, which has a level surface two 
or three feet below the highest tides. This is composed of fine, clayey 
mud, brought in and deposited by the tide, which cuts channels for its 
flow and ebb. None of our forest trees can endure salt water; and the 
marshes are left to a rank growth of the grasses and sedges peculiar to 
the sea-coast. On the south side of Long Island, and thence southward, 
the beach is frequently divided from the shore by extensive sounds or 
shallow bays, which are partly filled with salt marsh. 


MODIFIED DRIFT ALONG THE SEA-COAST. 173 


The shores of Rye and North Hampton are principally till or ledge, 
with frequent beaches and marshes of small extent. About forty rods 
south from the United States life-saving station and cable station, near 
Straw’s Point, the stumps of a submerged forest are exposed at low tide 
on the north end of Jenness’s beach. In July, 1877, more than seventy- 
five stumps could be counted here, the largest of them two feet in diame- 
ter and three feet high. Numerous specimens of the wood then obtained 
seemed to be all alike, and are pronounced by Mr. William F. Flint to 
be white cedar (Cupressus thyoides), Other stumps farther out projected 
above the water, and they are said to extend out to a depth five feet be- 
low the lowest tide, They have not been so well exposed for several 
years before this, and in 1874, when the cable was laid, they were not 
seen, being covered with sand. The most probable explanation here is 
that given by Mr. John L. Hayes,* who supposes that the forest grew at 
a higher level on the surface of a peaty swamp, which was protected 
from the sea by a beach. The beach has since been driven inland, and 
the mud of the swamp has been washed away; but the trees were inter- 
laced by their roots, and all sank together, so that they are now covered 
by the sea. Stumps occur in salt marshes near the head of Sagamore 
creek, on Little river, and in Hampton, probably where swamps have 
become more compact and settled within reach of the tide. If any 
change in the relative height of land and sea is now going forward on 
our coast, it would appear to be a very slow submergence of the land, 
not amounting to a foot in a hundred years, 

Little and Great Boar’s Head are bluffs of till, about 50 feet in height, 
which are being undermined by the waves. South from the latter point, 
a beach-ridge extends 15 miles, broken only by Hampton and Merrimack 
rivers, and bordered all the way on the west by a salt marsh, which aver- 
ages a mile in width. The beaches of Hampton, Salisbury, and Plum 
island are on its east side. A large part of these deposits was probably 
carried out to sea by the Merrimack river, and then turned back by 
waves and tide. 

It has been shown that the sea stood in the Champlain period 150 feet 


* Letter in Jackson’s Final Report on Geology of New Hampshire, pp. 280 and 281. A valuable essay was 
published by Mr. Hayes in the Boston Fournal of Natural History, vol. iv, 1844, on the ‘ Probable Influence 
of Icebergs upon Drift.” : 


174 SURFACE GEOLOGY. 


higher than now, from which level it sank to its present height, or lower; 
but no well marked beach-ridges have been discovered inland. 


REVIEW OF THE CHAMPLAIN AND TERRACE PERiops In New Hamp- 
SHIRE. 


The Champlain period embraces the time occupied by the final melt- 
ing of the great ice-sheet. At first its nearly level surface of pure ice 
lay above our highest mountain summits. As the melting advanced, it 
was moulded into basins and valleys, which, near the terminal front of 
the ice, coincided nearly with the contour of the land. At last the sur- 
face of the ice became covered with the abraded material which had been 
contained in its mass. A large part of this material was washed away 
by its streams, to be deposited in the modified forms of kames,* kame- 

, like plains, and valley drift. Through the whole of every summer during 


/> *Since writing the first part of this chapter, I have learned that, as early as in 1872, Prof. N. H. Winchell, state 
geologist of Minnesota, had been led by his observations of kames in Ohio and Minnesota to an opinion respect- 
ing their formation similar to that presented in pp. 12-14, which, when first announced in August, 1876, was sup- 
posed to be entirely new. (See citations below, under Ohio and Minnesota.) 

For the benefit of those who may be interested in this subject, and may wish to see descriptions of these depos- 
its elsewhere, we append the following list of authors who have treated, more or less fully, of kames: 

Canada. Principal J. W. Dawson, Notes on the Post-Pliocene Geology of Canada, 1872, pp. 26, 40, 107, and 
112; Acadian Geology, 1868, pp. 82 and 324. Geological Survey of Canada; Report of Progress for 1870-71, 
P- 349 (Robert Bell); do. for 1875-76, pp. 262 (G. M. Dawson) and 340 (Robert Bell). 

Maine. Prof. C. H. Hitchcock, Agriculture and Geology of Maine, 1861, pp. 271-274; do., 1862, pp. 388-391. 
Prof. L. Agassiz, Atlantic Monthly, vol. xix, February, 1867, pp. 213-215. 

New Hampshire. Dr. Edward Hitchcock, 77 tions of the A. jation of American Geologists and 
Naturalists, 1840-42, p. 198, Plate viii; also, Swithsonian Contributions, vol. ix, 1857, pp. 36 and 45. Warren 
Upham, Proceedings of American A iation for Adi t of Science, vol. xxv, 1876, pp. 216-225. 

Vermont. Prof. C. H. Hitchcock, in Geology of Vermont, vol. 7, 1861, pp. 95, 102, 150-152, and 190. 

Massachusetts. Dr, Edward Hitchcock, Geology of Massachusetts, 1841, pp. 356 (Figs. 62 and 65) and 366- 
370; Tr tions of the A jation of American Geologists and Naturalists, 1840-42, pp. 190-203, and Plates 
viii and ix; and Smithsonian Contributions, vol. ix, 1857, p. 44 (lowest paragraph). Rev. George F. Wright, 
Proceedings of Boston Society of Natural History, vol. xix, 1876, pp. 47-63. = 

Connecticut. Prof. James D. Dana, 77 tions of the Cc ticut Academy of Arts and Sciences, vol. ii, 
1870, pp. 70 and 71. 

New York. Geology of New York, Second District, E. Emmons, 1842, pp. 186, 323, 333, and 364; do., Third 
District, L. Vanuxem, 1842, p. 247. In this and other states bordering the great lakes, ridges of sand and gravel 
are found, which must be distinguished from the kames, being apparently ancient beach-ridges, formed when these 
lakes were held at higher levels during the Champlain period. Their present outlet through the St. Lawrence 
valley was obstructed by the ice-sheet, which seems here to have retreated from south-west to north-east. 

Ohio. Dr. J. S. Newberry, Geology of Ohio, vol. i, 1874, pp. 7, and 41-46. Prof. N. H. Winchell, Proceed- 
ings of American Association for Advancement of Science, vol. xxi, 1872, p. 165. 

Michigan. E. Desor, in Foster and Whitney’s Report on Geology of Lake Superior, 1850, pp. 196 and 205; 
do., part it, 1851, p. 258. 

Minnesota. Prof. N. H. Winchell, Geology of Minnesota, First Annual Report (for 1872) p. 62, etc. ; Report 
Jor 1873, p. 194, etc. 

Jreland. G.H. Kinahan, Geological Magazine, new series, vol. i, 1864, pp. 34, 89, and 189 ; do., Decade it, 
vol. iz, 1875, pp. 86 and 87. 

Scotland. James Geikie, Great Ice Age, 1874, American edition, pp. 209-237; do., second edition, revised ; 
London: 1877, pp. 210-252, 

Sweden. James Geikie, Great Ice Age, 1874, American edition, pp. 357-367; do., second edition, revised, pp. 
407-416. 


REVIEW OF THE CHAMPLAIN AND TERRACE PERIODS. 175 


the Champlain period, our rivers were swollen as we see them now in 
the floods of spring, but they were laden with far greater amounts of 
alluvium. The valleys were thus gradually filled with modified drift, 
which took the same slope with the descending current. In some in- 
stances (pp. 65, and 116-119) there is evidence that the ice-sheet in its 
departure was for some time a barrier, holding back lakes where there 
are now empty valleys, sloping to the north or west. If the principal 
lines of drainage throughout the state had been in these directions, such 
lakes must have been frequently formed during the retreat of the ice 
towards the north-west. With these exceptions, the deposition of our 
valley drift appears to have taken place in the same manner that addi- 
tions are made to bottom-lands by high floods at the present day. 

The modified drift, though extensive, constitutes only a part of the 
material which was contained in the ice-sheet. Probably more escaped 
erosion than was carried away by the glacial streams. When the ice 
was wholly melted, the part remaining fell upon the striated ledges and 
ground-moraine, being the loose upper till, with numerous angular boul- 
ders, which forms the surface generally throughout the state. Outcrop- 
ping ledges, however, are frequent ; and both the kames and valley drift 
rest upon the upper till. 

The modified drift deposits show that the ice retreated slowly, and 
with varying rates of progress (pp. 36, 39, 121, 122, and 149). Evidence 
of its reddvance has been found in only a few places, near the coast (pp. 
163 and 164). The ice-sheet appears to have continued uninterruptedly 
through a very long period (pp. 7-9). Doubtless it resisted the influence 
of the warmer climate and changed conditions before which it disap- 
peared, continuing late like the snow in spring. Its departure at the 
last was correspondingly rapid; and the hardier forms of vegetable and 
animal life were soon established near its retreating margin. 

During the recent or terrace period the work of deposition by the 
streams has not been equal to that of erosion, and they have excavated 
deep and wide channels in the Champlain deposits (pp. 15 and 16). In 
this process terraces have been formed, sloping with the stream. Neither 
the deposition nor terracing of the modified drift requires any submer- 
gence, as by lakes or the sea. These deposits have the form which they 
must naturally take, in being rapidly brought into the valley by floods, 


176 


SURFACE GEOLOGY. 


and in afterwards being partly excavated by the rivers in the process of 


deepening their channels. 
A table is added, showing the formations which have been described 


in this chapter, arranged in the order of their deposition, beginning with 


the oldest. 


GLacIAL AND CHAMPLAIN Deposirs IN New Hampsuire. (DrirFt, 
QuATERNARY, PosT-PLIOCENE, PLEISTOCENE.) 
FORMATIONS, AND THEIR SoH ONCE. peace: 


DISTRIBUTION. 


Lower till, p. 9, deposited during 
the glacial period, pp. 4-11; found 
throughout the state, p. 4; often ac- 
cumulated within 25 miles from the 
coast, and rarely farther inland, in 
massive, oblong, rounded hills, 50 to 
200 feet high, pp. ro and rox. 


Till; ground-moraine; glacial, 
unmodified, or unstratified drift; 
boulder-clay ; hardpan. 


Characterized, p. 9, by its glaciated 
stones, its dark and usually bluish 
color, and its compactness and hard- 
ness. Formed, pp. 5 and g, by long 
continued wearing and grinding, be- 
neath the moving ice-sheet ; overly- 
ing rounded and striated ledges, pp. 
4and 5, 


intercalated clay and sand, 
pp. 6, 17, and 18; about Winni- 
piseogee and Squam lakes, fre- 
quent, varying in thickness up 
to 30 feet, pp. 131-137; else- 
wrPrSy rare, pp. 108, 163, and 
164. 


The hypothesis of Mr. Jas. Croll, 
that an ice-sheet was accumulated 
and melted away several times dur- 
ing the glacial period, is considered 
In pp. 5-9. 


In the Lake district, deposited 
where drainage was obstructed, in 
hollows melted under the margin of 
the departing ice-sheet, p.137. Near 
the sea-coast, the Champlain period 
was interrupted by a readvance of the 


ice, p. 163. 


Upper till, p. 10, found 
throughout the state, p. 4; thick- 
ness, usually less than ro feet, 
but varying up to 20 feet or more. 


By many writers not distinguish- 
ed from lower till, both being in- 
cluded as till, glacial drift, or boul- 
der-clay. 


Characterized, p. 10, by its large 
angular boulders, its yellowish or red- 
dish color, and the comparative loose- 
ness of its whole mass. Contained, 
with the modified drift, in the ice- 
ehects and deposited when this melt- 
ea. 


Kames, p. 12, found through- 
out the state, the extent of series 
varying up to 25 miles or more, 
and the height of ridges varying 
up to 250 feet. 


Merrimack series, pp. 84-93. 
Ossipee series, pp. 144-149. 
Andover, Mass., series, pp. 


167-170. 
Haverhill, Mass., series, p. 
170. 


Connecticut series, pp. 43-48. . 


Gravel ridges; horsebacks; mo- 
raine terraces; eskers, in Ireland; 
asar,in Sweden. A list of authors 
upon this subject is given in the 
foot-note on p. 174. 


Deposited, pp. 13 and 14, by gla- 
cial eee at the final melting of the 
ice-sheet, in channels formed upon 
the surface of the ice. When the 
bordering ice-walls and its separating 
ridges and masses disappeared, the 
gravel and sand remained in long, 
steep ridges, or in irregular short 
ridges and mounds, enclosing bowl- 
shaped depressions. 


Kame-like plains and broad 
ridges, pp. 17, 18,155, and 156; 
found near the coast, about Do- 
ver, and southward to Newbury- 
port, varying in thickness up to 
roo feet, pp. 155-164, 170 and 
171. 


Nore, The valley drift, kame- 
like plains and broad ridges, kames, 
and intercalated clay and sand, are 
all embraced under the title »zodz- 
fied drift, which is defined at the 
top of p. 4. 


Kame-like, in having been deposit- 
ed, pp. 155 and 156, while the adja- 
cent valleys and lowland were still 
occupied by portions of the depart- 
ing ice-sheet. 


Valley drift (gravel, sand, blue 
and gray clay, sand), p. 15; in 
valleys throughout the state. A 
large part of these beds has 
been excavated by the rivers 
during the recent or terrace pe- 
riod, pp. 15, 16, 21, 27, and 82. 
The highest terraces are rem- 
nants of flood-plains which were 
annually overflowed at the end 


DEPOSITED DURING THE CHAMPLAIN PERIOD, p. 11. 


ing in height up to 200 feet above 
| the present streams. 


| of the Champlain period, vary-- 


The blue and gray clay, pp. 94, 

» 153-155, and 158-rx6r, are proba- 
biy equivalent to the Champlain 
clay in Vermont, the Leda clay in 
Canada, and the Erie clay in the 
basin of the great lakes. 


Deltas, above the highest normal 
"terrace, pp. 16, 29-31, 33, etc. 

Dunes, blown upward from the 
valley drift, pp. 17, 41, 73, and 147. 


See note in the next space above. 


Brought down by glacial rivers from 
the melting ice-sheet, filling the val- 
leys generally to the level of their 
highest terraces. This deposition 
and the subsequent formation of ter- 
races required no submergence nor 
change in the height and slope of the 
land, pp. 15, 16, and 18. The height 
of the sea in the Champlain period 
was about 150 feet above its present 
level, as shown by marine shells, pp. 
18, 165, and 166. 


fea 
uf 
Q 
eS) 
[2] 
a 
ra 
Qo 
rd 
° 
> 
= 
Ga 
x 
ss 
= 
a 
os 
z= 


CHAPTER II. 


GLACIAL DRIFT. 


PE usin has been already made to the former existence of an 
immense thickness of ice over the whole of New Hampshire, as 
well as the entire northern portion of our continent. This ice-sheet is 
supposed to have been the natural accumulation of frozen moisture from 
the atmosphere, requiring thousands of years’ time for its gathering 
together. Like the similar glacial masses upon both poles of the earth, 
this one must have been slowly moving towards the equator, especially 
near the melting edge. A formal proof of our statement is unnecessary, . 
since the phenomena presented to us universally over the state speak for 
themselves ; and it will be difficult for any one to read an account of the 
striation and embossment of the ledges, about to be described, without 
believing in the existence of this sheet. As the subject is one of great 
interest, and sound generalizations can be drawn only from observations 
taken in every part of the state, much attention has been devoted to the 
collection of facts during the whole time of our survey. Such of these 
as are especially important will be named: hundreds of them will not 
be mentioned. Many facts belong to a class, and we need therefore 
describe with particularity only one example of them. Should the want 
of time and space prevent a full discussion of the causes inducing the 
cold climate, the method of transportation, the chronological date of the 
period, and other related topics, the reader will find an excellent sum- 


mary of conclusions of this nature in the preceding chapter. Treatises 
VOL. Ill. 23 


178 SURFACE GEOLOGY. 


have been written by several geologists upon these subjects, which can 
be consulted by those desiring further information. It is obvious that 
our first duty is, to state whatever facts have been observed, and then 
discuss the general bearings of the subject, if an opportunity is pre- 
sented. It may be premised, however, that the glacial theory of the 
origin of the cold and of the dispersion of the materials seems to explain 
all the phenomena better than the older view of the agency of icebergs. 

Any complete discussion of the phenomena must relate partly to the 
effects produced upon the ledges by the ice-movement, and partly to a 
description of the materials transported, their position, shape, size, 
amount, etc. We will first speak of the action upon the ledges. The 
ledges have been broken, rounded, or embossed, planed down, smoothed, 
and striated. The formation of pot-holes took place after the ice began 
to melt. 


Fracturep LEpDGEs. 


Since the Helderberg period, the rocks of New England had been 
subjected to sub-aerial decomposition, whereby they were softened and 
rendered friable to great depths, often as low as the water level, or as 
much as a hundred feet. The change was mostly chemical, consisting 
of the removal of the alkalies, and the disappearance of lime and magne- 
sia, by solution, the residue being clayey. Hence the ledges were in 
excellent condition for removal by the ice-sheet. Enormous quantities 
would be easily rubbed off, and then assorted by water. Besides the 
decomposed rocks, the ice removed perhaps as great a mass of the solid 
portions, which now constitute boulders and the pebbles of the till. Still, 
this ice action does. not represent all the erosion that has taken place in 
our state, as may be proved by calculations of the mass that has been 
removed from the ledges to fill up gaps in the strata. It has been gen- 
erally estimated that this amounts to as much as the average height of 
the land above the sea, or 1,200 feet in New Hampshire. The condition 
of the surface in the Southern states, in Brazil, and in certain sheltered 
spots in Minnesota and Massachusetts, as described by Hunt, Hartt, 
White, and others, illustrates the nature of the land surface with us, be- 
fore the ice acted upon it. 

In the earlier New England reports, several cases of ledges fractured 


GLACIAL DRIFT. 179 


by the drift have been described. Clay slate is very readily broken ; and 
the simplest cases of fracture are those noticed in that rock, as in the 
quarries at Guilford and Northfield, Vt. Sometimes the fractures have 
been produced by the expansive force of freezing. Water, penetrating 
the seams, freezes, and thus, by expansion, wedges apart considerable 
masses. These, if on a precipice, fall to the base, and accumulate in 
large amount. Nearly every precipice in the state exhibits more or less 
of this work. It will be seen, also, in the flumes about the White Moun- 
tains, and has been described in Volume I], page 158. 

The frontispiece of Volume I exhibits the condition of the ledges in 
a certain stage of decomposition, between the upper limit of trees and 
the snow line. Doubtless many square miles of surface were thus cov- 
vered by angular blocks before the ice-movement commenced. 

The most striking evidence of the action of ice breaking ledges is 
where the stone has been fractured by a lateral thrust. These are com- 
monly seen about large quarries. A single example will suffice for many 
that have been observed. Fig. 49 is 
a sketch of this phenomenon at the 


4 


Amoskeag granite quarry in Manches- 
ter. It is upon the north-west slope “. —__—_——______ ] 
of a hill, in a position where it could 

be struck by the ice descending the FIG. 49. 
Merrimack valley. The surface is smoothed and striated. For eight 
or ten feet in depth the granite is broken into irregular pieces, so that it 
cannot be used for underpinning. Beneath these pieces, the stone is 
sound at least to the depth of thirty feet, or as far as the excavation has 
proceeded. One can readily see the line between the broken and sound 
stone upon the east side of the quarry. That the fracture was occasioned 
by the ice-movement is proved by the fact of the smoothness of the sur- 
face fragments. The pieces can be taken out and matched together 
again, just like a pavement. Had they been fragments prior to the ice- 
action, they would have been moved away by it. The same phenome- 
non occurs, though less noticeably, at Bodwell’s quarry, close by. If 
the ice had reappeared in the Merrimack valley, these broken frag- 
ments would have been removed, and a new smoothed and striated sur- 
_ face would have been planed upon the solid granite. 


180 SURFACE GEOLOGY. 


There is teason to believe that examples similar to the above exist by 
the hundred. They are not usually visible, except where excavations 
have been made. 


PLANISHING AND EMBOSSMENT. 


Should the earth be entirely removed from the ledges, the majority of 
them, save where subsequent erosion has obliterated the marks, would 
show upon their exposed sides a planing down and rounding. These 
ledges are not planed down fiat, like a floor, but are rounded, retaining 
essentially their original forms. It is a common sight, when travelling 
along the deeper valleys, to observe, above the line of the modified drift, 
numerous rounded, dome-shaped ledges. A close scrutiny will disclose 
the fact that these have been worn the most upon the northern side, 
while the southern escarpment may be rough and uneven. Hence it is 
obvious from which direction the force proceeded which planed down the 
ledges. The sides most worn are those which have been struck. We 
often speak of the struck or s¢oss and the dee sides of these rounded ledges. 

The embossed ledges are often grouped in considerable numbers, 
looking as if there were an assemblage of haystacks closely crowded 
together. Precisely similar phenonena occur in the glaciated region of 


FG. 50.—EMBOSSED Rocks ON Mt. MONADNOCK. 


the Alps, where De Saussure applied to them the name of voches mou- 
tonnes. An example of them, as seen in New Hampshire, is given in 


GLACIAL DRIFT. 181 


Fig. 50. This represents an area of about five rods square on the south- 
west side of Mt. Monadnock. Here they occur near the summit of the 
mountain, not along the sides of a valley. 


There are many examples of embossment in the state as good as these. I have 
noted a few of them: The top of Mt. Kearsarge; about the Lake of the Clouds, be- 
tween Mts. Washington and Monroe, though the action of the frost is injuring their 
perfection; along the Pemigewasset valley in Woodstock; Baker’s River valley, in the 
west part of Plymouth and the east part of Rumney,—also higher up, less perfectly ; 
along the Northern Railroad, between Orange summit and Grafton Centre; Sanborn- 
ton, west of Cawley’s pond. The Huronian and Cambrian slates of the Connecticut 
valley abound in fine examples of these rock domes. Others are specified in the 
column of remarks about strie, further along. The narrow belt of rock in which the 
principal mica quarries are located, between Groton and Keene, is noticeable for the 
very fine embossment of the ledges all over its course. Granitic and calcareous rocks 
decompose readily; but the general form of the embossment will remain after the 
markings have been obliterated, so that a practical eye will recognize the fact of their 
glaciation. 


STRIATION. 


By far the most important effect of the ice-movement is the striation. 
All these domes and the worn sides of ledges exhibit lines more or less 
distinct, or passing into grooves which have been produced by hard rock 
fragments frozen into the bottom of the ice-sheet. As the mass moved 
along, these fragments acted as chisels or gouges, deeply scratching 
the ledges. It is obvious that the grooving instrument must have been 
harder than the rock affected; hence pieces of soft rocks, like limestone, 
would not leave any mark of their passage. These markings are often 
obliterated by disintegration, and it is difficult to find their direction, 
Several expedients may be resorted to: First, search for veins or pro- 
jections of tough materials, upon which faint lines may possibly be 
found. These harder substances show the action, because they have 
successfully resisted disintegration. Again: it may be necessary to wet 
these projections, or the whole surface of a smoothed rock, in order to 
discover the direction of the striz. Sometimes deep grooves may be 
found, which will indicate the course as well as scratches. 

These markings vary from the finest scratches visible to deep furrows. 
They may be straight or curved, the latter where the abrading chip 


182 SURFACE GEOLOGY. 


‘turned to one side, and was speedily crushed. Again: pieces of the rock 
may be chipped off, as if the chiselling fragment was not held down 
firmly to the ledge, but had a jarring motion. Then there are the 

Lunorp Furrows. lunoid furrows. Vose describes them upon the 


Green hills in Conway. Some seen on their north- 


~~ NLA ern slope have axes running about S. 40°-48° E, 
Fig. 51. 


and are from one to four inches in diameter, A 
section of one is given in Fig. 51. It appears that 
the steep side, A, is always on the up-hill end of 
the furrow. Four others were noted at the south 
end of these same hills, upon a horizontal surface 
near the summit. They are figured in Fig, 52, are 

FIG. 52. 11 inches long, 7 wide, and 4 deep, their direction 
being that of the dotted line, N. W. and S. E. These axes indicate the 
course of the ice-movement. 


The origin of the lunoid furrow is given as follows by Dr. A. S. Packard, Jr., who 
observed several of them on a hill near Goodrich falls in Bartlett, with the course S. 
17° W., also on Mt. Baldface:* ‘It is known that the glacier is in constant motion, 
advancing a few inches in summer, and then contracting in winter. Now imagine a 
stone frozen into the ice, and thus acting as a gouge. Pushed onward, and then with- 
drawn by the powerful hand of the ice-king, it soon wears this peculiar shaped hole, 
then turns out of the rut, and catches again in some inequality of the rock, and makes 
another lunoid furrow, or, perhaps, a series of four orfive, often very regular in form, 
though the distance between them may vary.” 


The striz in New Hampshire vary considerably in their direction. 
Before discussing the reasons for this variation, it will be proper to pre- 
sent a list of all the observations of their occurrence that have been 
recorded. They are all my own, except the few that are otherwise noted. 
I have carefully reduced the compass to true courses. I hope to present 
in the atlas a map showing these marks laid down with great care in con- 
nection with the relief features of the ground. A very few observations 
may be added for the adjoining territory, or what is included in our gen- 
eral map. 


* American Naturalist, vol. i, p. 265. 


CourRsESs 


GLACIAL DRIFT. 


183 


oF Stri@ in New HaAmpsuHIRE. . 


LOCALITY. 


REMARKS. 


Pittsburg,—mouth of Indian stream.. 


Stewartstown,—mouth of B shop br. 
Clarksville,—M. Perry’s. 


Colebrook —J. S. Chase’s...... 


Littleton,—Mann’s hill........ 


Haverhill,—Woodsville.. 


Newbury, Vt. ,—village.... 


Milan,—west 


Lisbon,—near Mink pond.. 


i mile S. E. from Back lake 
Outlet of Connecticut lake. 


. Brainerd’s ...eceesssveaneces 
South hill... .ccaccecsseassscecs 


S. W. corner, top of hill. 
J.Gethercole’s, “  .. 
J. Keyser’s..... 


Young’s—east part....seeeeesens 


Dixville,—top of Dixville mountain.. 
Dalton,—near Sumner house. 


Copper mine.,....... da oeeen 
R. Miller’s.... 


Top of hill, do........- 
G. Lang’s.. 
Top of Gardner’ $ mountain. 
Way’s copper mine ..... 
Top of Gardner’s mountain. 


Lyman,—No. 1 shaft, Paddock mine. 


Land of Martin and Swett....+.: 
Near do......-.000- oie 
Hill back of Steery’s “house. atte 
Dr. Brown’s barn........ a: wien 
Near Bedell’s house........ 
Near Bath line south from Dow! ‘s, 
Hill opposite J. Williams’s... 


“ 
Huronian........ 
Mica schist 
Huronian.. 
Clay slate 


Lisbon group 
Lyman group.. 
‘ 


Lisbon group i 
“ 
a one 
Gr ones 
Lyman group.... 
Conglomerate.... 


North of S. B. Bey Bacinecins we cBbiat 


North of Young’s pond 
Moulton hill 
Dan. Miner’s ...........5 orrey) 
S. W. part of Parker & Young’s. 
Stakes 17 P. to R. (vol. ii, p. 296). 
Near R-6.. 


A. Annis’s.. a sisie wisieieigradeleseie 
R. Moore’s, south of ‘Cow brook. 
Ridge between Cow and Parker 
brooks........ sees 
Near Dalton..... 
Farr hill, near fossils. 
Milliken’s saw-mill... 
East of G. Wheeler’s—hill . 
A. P. Hubbard’s........ 
West side Fitch hill.. 


Soapstone Bed eis csaccasisersiciowiclers 
¥Y% mile N. W. from limestone... 


eer tas —near P. McLary’s.... 
Ridge west of Mt. Pleasant..... 


art . 
Hodgdon hill...... 


Near poor house ( (further east).. 
Sugar hill, near Quimby’s......, 


-| Clay slate... 


-| Conway group... 


“ 
Huronian.... 


“ 


Clay slate... 
Huronian... 
“ 


aaa 


Gneiss « aie 


Quartz rock.. 
Huronian.. 
ii3 


Cois schists. ses 


wn 


AnMnnMMNN nw, 


_ 
a) 


nan 


aS 
OO OGY FOS 


Lal 
Nu wh |» Sma 
50 OS 


Srp eh Sehere Sh 


° 
on vn 
i) 
oN 


“I 


a 


til 


Numerous embossed ledges. 


Very distinct. J. H. Huntington. 


“ “ 


Grooves. 


Local glacier. 
Very distinct. 


J. H. Huntington. 


ta ao 


J. H. Huntington. 


Striz abundant in North Monroe. 


Finely embossed ledges. 


Deep grooves. 


Running up hill. 


Down small valley. Different from the 
usual direction in the neighborhood. 


Diagonally up hill. 


Numerous and fine. 


On vertical wall. 


Up hill, athwart valley of Smith brook. 
Top of hill. 


These striz cross the Conn. valley. 


The second set only a few stragglers. 


Numerous. G. W. Hawes. 


Very distinct. J. H. Hunti 
Magnificent, 2 acs 


J. H. Huntington. 


184 


SURFACE GEOLOGY. 


Courses of Strie—Continued. 


LOCALITY. ROCK | goes | REMARKS. 
Hill-top east of Bronson hill..... Gneiss .......005 S. 59° W. 
Hill south of Atwood mine......| Huronian........]  S. 8° W, 
Between Streeter pond and 
Lisbon.....ccccsececeseseeeee| Clay slate........} 5.80 W 
Jesseman’s.ecseseseceeeuees sonst LAMESLONG ci c0a-ee See a Two different localities, the same course, 
Bem sue: Fe part, fee of hill. Gneiss.... Ss. 3° Ww. 
outh slope of Mt. Agassiz.....+ eee: Sug? Wi N. W. slope A; 
C. Kenney’s and Quimby’s......] Gneiss...........] 5. 28° E. striated er abundantly 
Line of Bm., near iron works....] Gneiss... S$. 3° W. | Struck side very evident. 
re Agassiz—top deste . a S. 8° W. 
way up from toll-house. . ame S. 12° E, hill. 
é Elan toons sigr@eceieseinre . ce S. 28° W. Yen 
To: BIGREIN Siew damnonniesnncs ‘i ce oi S. 4° W. 
Landaff, eh hil above J. Clough’s. Quartzite..... eee] S230 W. 
Bath, —I. Cool OY Sh invetesniar ojereiersjorsieceisieie Lyman group.... GS 
Top of Gardner mountain -++| Huronian ... S. 12° E. 
West side..........66- «6 S. 3° W. } very fine. 
Franconia,—R. Wallace’s Gneiss . S. 8° W. 


White Mountains,—ridge 
Mt. Madison.. 
Mt. Adams, wes 


Lake oie Clouds... .ee-seseees 


Between Pleasant and earn 
Between Pleasant and Clinton.. 
Near top of Clinton, north side.. 
Clinton, south peak. 
South end of Mt. Webster 
| Top of Mt. Webster 
Mt. Washington carrlage-r "d, low. 
erend.. 


PrestpENTIAL RANGE. 


2 miles up... 


2¥% miles Ses 
5 miles up.. 
Glen house * 
Do. £ mile south is 
Head of Tuckerman’s ravine... 
Gorham,—about village............. 
Shelburne,—hill 150 ft, above R. R.. 
Extreme north point oa curve.. 
Clement’s brook.... 
Near Maine line.. 
White Mountains 
Mt. Lafayette, above Eagle pai, 
Bald mountain 
es Heid alee t 


rie eee ee 
Mt. Willey, top? 
Hart’s mountain. 


&e way from top 


to saddle between Pequawket 
and Bartlett mountain, 2500 
feet high 
The “ Notch,’ ’—south side Mt. 
‘Willard and near railroad 
On railroad south side of Willey 
brook .....seseees eiselaielciea ese 
Top of Mt. Willard. ............ 
West side Sandwich notch near 


Montalban....... 


ce 


Ff caceeveesens 


Montalban... 
“¢ wee 


“ 


Porph. gneiss.... 


Granite........+- 


EOP. vercecneses 


Gneiss....eeeeeee 


Lake gneiss...... . 


S.3 
Ss. 22° E. and 

“| §. 52° BE. 

S. 30° E. 


: $.47°-52° E. 


S. 50° E. 


8.4 


a 50 E, 
Ss. APE. and 
"| S. 60° W. 


S. 42° E. 
S. 2° E. 


Southerly. 
S. 23° E. 


S. 70° E. 


Rock struck on north-west side. 


According to W. G. Nowell. 


Smoothing distinct; strize obscure. 
Intersecting. 
Very distinct. 


Rock face; 200 by 40 feet exposed. 
N.E. clearly the side exposed. 

Well defined example of the same on 
vertical walls. 

Upon an easterly dipping slope of 30°. 

Tngesenting: wall surface freshly uncov- 
ere! 


Modern strize made by falling stones. 
Stoss side points up valley. © 


Many large boulders above lakes. 
Large boulder of B’m gneiss on top. 


Wall. 
Down hill. 
C. T. Jackson. 


Intersecting. G. L. Vose. 


Down valley. 


Down valley; seen both sides of track. 


GLACIAL DRIFT. 


185 


Courses of Strie—Continued. 


TRUE 
LOCALITIES. ROCK. COURSE. REMARKS. 
Saco valley, below Bemis’s......] Gneiss.......++++ seveaseeeeseee| Wall; down valley; recently excavated 
by railroad. 
Duck Pond stream.............+ ESS sce apeltargiels S. 18° E, Wall inclined 45° W. 
Ossipee mountain—Mt. Whitti- 
€T—tOp..ss eee 


Same—east side.. 
Bartlett,—N. E. part.. 


Hill adjoining Goodrich falls.... 
Jackson,—last house next Carter 


NOtCh veseocuiwi esis wees 
Thorn mountain—top. shat 
Mt. Baldface—top ......--+.+.++ 
Thorn mountain, depression on 

north side 


Benton,—Mt. Moosilauke—top. 
20 rods east of summit 
Mt. Moosilauke, 94 

Warren,—back of Me 

end of turnpike 
Berry brook.. 


way up.....- 
rrill’s, lower 


1 mile south of Kelley pond. coat 
North of I. H. Kelley’s......... 


Wentworth,—near village....... sedis 
Rumney,—West Rumney, north side 
OL AT VERE. ci:fspavasejeraereies valsiaiesniavasace 

Hill south-west of village....... 
Tower COW iiss iss vicjeieve:ciesesesainneiisie 


Baker’s River valley............ 
r mile east of village. c 
Up hill towards Groton. 


. Kelley’s ..... enone 
E.. Blodgett! xcssinissesoin sietevceaiaveterers 
Plymouth,—west line...........0.05 


Village—W. edge R. Easter .... 
South side Plymouth mountain, 
¥% mile east of Hebron line.... 
Line of Hebron and Plymouth. 
Top of Wolf hill....... 
¥ mile south of village....,..... 
Hebron,—summit near line of Ply- 
mouth 


North end 
West 


West part 
Summit between Groton 


and 


(Mt. Pemigewasset, Lincoln. 
North Woodstock. 


South part.. 
Thornton... 
ec 


top of moun 
Russell pond...... 

S. W. from H. Fifield’s 
Near M. Sargent’s.. 
“« H.K. ill... 


PEMIGRWASSET VALLEY. 


Iderness,—Mt. Prospect—summit, 
ee W. side. 


24 


Ho 
VOL, III. 


Granite.. 


“ 


Montalban. 
te 


Granite 


Slates issevernareevion 
Mica schist. . 
«e 


Mica schist...... 
Mica schist 


ce 


Andalusite schist. 
Montalban .. 


Ferrug. gneiss... < 


Montalban ...... 
ee oe 


“ce 


Porph. gneiss... 
Montalban ...... 


Craplte ss 

‘orph. gn 

Gneiss oe 
€ 


Porph. gneiss.. 2 
Montalban ...... 


Porph. gneiss. we 


“ 


S. 47° E. 
S.329-S. 37°E. 


s 


iS. 


ANANPNNNNNNNH A nnannn nun 


w 


. 53° E. 
17° W. 


A. S. Packard, Jr. 
A few cross valley, S. 33° and S, 83°E., 
curving around a ledge. 
A.S. Packard, Jr. 
ee 


G. L. Vose. 

Down valley. 

Local or slide. (?) 

Down tributary of Baker’s river—local. 
Down valley. 


Grooves down the valley. 
Down valley; rather obscure. 


Wall 5 feet high. 
Very distinct. J. H. Huntington. 
Corresponding to bend of valley. 


Wall. 

On wall 40 feet high ; hill opposite high 
and precipitous. 

Down hill across valley. 


Partly on wall. 


Acres of embossed ledges at north base 
of Kimball hill. 


J. H. Huntington. 


J. H. Huntington. 
On vertical wall, with valley. 
Magnificent embossment of mountains. 


Faces Pemigewasset river. 


} W. Upham. 


186 


SURFACE GEOLOGY. 


Courses of Strie—Continued. 


TRUE 
LOCALITIES. ROCK. | COURSE. REMARKS. 

Shepard’s hill ...ssesseceeeerees Porph. gneiss.... S. 62° E. 

Squam mountain—top.. , aieiais 
Ashland, —near depot........- OO gag Bator Ss. 425 E. 

Village turn to lake, hill rons Ferrug. schist....} 8. 326 E. : 
Waterville slide....... Labradorite... vere INES 325, WwW. Perhaps made in 1869. 
Sandwich,—W. of vil. J. Gneiss .. «| N. 7° E. 

M. Bean’s. ee N. 83° E. , 

West line. ar S. 82° E. Down a valley depression. 

N. E. corn ae N. 85° E. 

North foot of Red. full esos elas aioe Sienite.... N. 80° E. 

S. Dinsmore’s. -| Gneiss.. : eae & 83°F. 

At notch.,.. ell, ABS ssie . - 60° EB. Two places, W, Upham. 

4 mile north pear SE pond. OE aloivie aiaiois East. W. Upham. 
Moultonborough,—near town 
line. . femervert 8 S. 55° E. 

H. Smith’s. oo $.57° E. 

Red hill, nea: su Ke S. 62° E, 

D. Vickery’ Se ae S.72°E. Obscure. 

Center Harbor,—w 
Mrs. Sutton’s. S. 72° E 
Middle of townsh: S. 42° E. 


Common all through 
Near M. Wade’s, promontory of 
Squam lake . 

‘West of Bear pon 

Tuftonborough,—'‘‘ Co 

Near Melvin hill... 
Below Melvin village . 

2 miles south of ‘‘ Corn 

¥% mile south of last... 

Welleherin h,—west side 

16.3 M. Garland’s). 

re of Trask Hilbvaceacs 

1 mile N. E. of Wolfeborough 
Centre (E. of L. Shotridge’s Bie 

Porcupine ledge.. 


Trask 


. Tibbetts’s.......e.seeeee 
RH. Piper’ 's, north side of sae 
Delight .. Soe 
Tumble-down Dick... 1.0022 0071 


Nowh corner of town.. 
2 miles south of last... 
Perkins’s....... weet 
. F. Stoddard’s ......... oerels 
Top of Moose mountains 
200 feet lower.. 
Wakefield,—L. C. Perry 
"South of SAnDOERte 55 junction. 
Top of hill near J.'Copp’s....... 
North of S. ‘Cook’s—high | land.. 
Three Tibbetts’ houses 


Near East pond.......... seteiets 
Ossipee,—East of Leighton’s corner. 
ill south of I. L. Sanders’s . 
Freedom,— Small hill west of village. 
W6ods’s veseseceeceeseucees 


Madison. —J..L. Frost’s, near village. 


R. Brown’s, north of village..... 

x mile west of Silver lake........ 

Gline mountain (road over)...... 
Eaton,—hill, north-east corner....... 
Tamworth, —Chatham hill, near top. 
South of Chocorua house........ 
Top first rise towards Mt. Cho- 

corua...... 

Top of second do. CRC TP EY 

Side of Mt. Chocorua.......0.65 


Meredith Neck,—Rollins hill..,,.... 


Advent church on Neck......... 
2ms. N. of M. village—summit.. 

East of Long pond..........0065 
East line, next Center Harbo 
Centre—hill to the south. 
Village..... wieiwiaiziareterstorare 


“ 


n 
zc} 
° 
ss 
R 
ica] 


Two last on hills west of Lower Beech 


Rather obscure. 


Towards village of Freedom. 


Excellent ; broad floors. 


G. L. Vose. 


“ 


C. T. Jackson. 
ae Fe is one large embossment 30 feet 
long, ro feet high, and zo feet wide. 


5° less easterly 50 ft. below the summit. 


GLACIAL DRIFT. 187 


Courses of Strie—Continued. 


TRUE 
LOCALITIES, | ROCK. COURSE. REMARKS. 


New Hampton,—N. W. Part, lag 


deposit........... sevseeeeeees| Andalusite schist.| §. 37° E. 
Harper’ shill. Porph. gneiss:...] S.52° E. Plain, and running up hill. 
Centre .. e S.42° E. ‘Abundant ; embossed ledges numerous. 
Edge, ne S. 52° FE. . 
Beyond.... S$. 379 E. Course with valley. 
West edge of N. Hiv lag e $.57° E. 
North side Burleigh mountai S. 32° E. Down valley; many emb. ledges here. 
North side ne ie hill.. S. 37° E. of oi ef 
§. 27° E. 
about g 27° E. 
wrens] Stone EK, 
Porph. gneiss....} S.35°E 


Ferrug. schist....] §.37° E. 


is -{: S. 42° E, 
Bill bin of L. Gove’s.. Mica Schist.. . 
Gilmanton line.. 
Top of Mt. Gunstock .. 
Marks’s island, Winn. Take... 
Sanbornton,—Back of Sanbort’n Sq., 

1 mile to the north-west....... 
North part—T. B. French’s 
Ridge in north part..... 
Further south .. 
GUE sserecssnietesiarnininiotarasce 
Road west of Hopk nson hi 
1 mile north ae 


TU] Si gg08 


Trap dyke... a 


A single scratch. 
Gneiss ..... 


Two places. W. Upham. 


Gilmanton,—hotel .... - 
South-east from hotel . 


TP BIW S vaissciesisparacecaiere . 
North-west part of town .. 
C. A. Hackett’s ........ ate 
East part, top of hill 
Tannery, south edge of town.. 
North-east part........, 
Hall’s hill, south-east Part. 
2 miles east of Peaked hill... 
Tilton,—near village........ 
Alton —east line.. 
J. Varney’ 5. 
iu Morrison’ 's; west of. lake 
Straw?s e-cceeatcn's . 
w. ai S. Nute’s, top ‘of dge. 
H. Hunt’s, north-east part.. 
New Durham, —B. F. Sawyer’s ‘and. 
. Burnham's, see setececcees 


Grooves. 


W. Upham. 


Also a few straggling to S.; all up hill. 


est part veces te 
Brook in east part ue 
oR ee See ne 
AY. “ 
“Ridge” sees ‘ Reece 
Church on ridge and m. west. oe . W. Upham. 
Barnstead,—S. W. oe seoeeess] Gneiss 2... 
Clark’s corner .. a ca wists 
Strafford,—Corner. Mica schist...... : Obscure. 
s. Young’ S. = ff i : 
Ridge north. fe 
op of ridge, north-west ] te we 
South of D.. Marsh’s Par 8 
North end of Bow lake «| Gneiss . 
1 mile north ss 


2or 3 miles north- erst in Paul 
Tasker’s pasture.. 

North-west corner. 

East of Isinglass river. 


Quartz.......... 
Mica schist, 
‘ 


G. W. Foss’s. 

A. « 

¥ mile s. Ww. from south corner. 9 Two places. W. Upham. 
Fis atiiciseh rest side Fes mt. ot . 

oO Gtis'ss soe seseennn mains i 


188 


SURFACE GEOLOGY. 


¥% m. S. from Canterbury centre. 


Courses of Strie—Continued. 3 
LOCALITIES. | ROCK. | EGOuGE. REMARKS. 

Milton,—top of Teneriffe mountain..] Mica schist...... Ss. 42° E. Grooves seen 50 feet long. 

N. Oberts’S..-csccrsenscece *e aeitaasg 
Rochester,—north-west from village. Andalusite SCHIS EA) 3.00% sjecers sisuerdiors Abundant; not measured. 

2miles south...cccescceesceeees S. 24° E 

J. F. Young’s ... Mica: schist seosel S.27 E 
Barrington, —Wheeler F S. 429 E 
Rollinsford,—E. S. Clement’s ee S$.12° E 
Durham,—W. P. Sherburne’s... . S. 37° E 

West of J. W.E. Thompson’ s. S. 52° E 

North-west part .......- agenaniyaroNas $.57° E 
Lee,—school-house No. 1. S. 42° E. 
Northwood ,—centre ..........20-00+ S.37° E 

Top of Saddleback mountain.... Sh sieartiers S. 32° E Grooves. 
Pittsfield,—Catamount hill—top..... Mica schist...... S. 42° E 
Chichester,—r1 mile south-east from 

Kelley?s corner. cs seis missle | nioeriereiaioiarainre sisters 20° E. W. Upham. 

Deerfield,—hill-top near J. Chase’s.. Merrim’ ck schist. 40° E 

Middle part... cc... cece see cnes Gneiss ....... aii ee 

North side of Pawtuckaway..... FE is , 2° E, 
Epsom,—east line ..........205 5 BE mreux ‘ 36° E. 
Canterbury,—south edge Montalban . : 16° E. 

Further north.. 6 ‘ : 20° E 

Soapstone quarry spe raiets Soapstone.. z 26° E 

tmile N. E. from North Concord |........ . 

EAE OIL sagan sien cisdordeapsscfecercinseoierns . 15° E. W, Upham 


Ym. N. of Crane Neck pond.. 
4 m. N. W. from Shaker Village. 


POOUNNNNNNONHH NAH nH 
“ 


Franklin,—west part of village....... 17° E. 
. George’ S asncuyeseye eee aes 32° E. 
North of village. e 27° BE. 
Near-Hill 5.00. cwvar 42° E. 
Near north-east edge . 22° E. 
South-west corner ......... 42° E, 
z mile north-east from falls. 15° E. 
Hill,—near church..... 2 22° E. 
Andover,—near centre.. " 62° E, 
POtte BA CE ris sicregaiavasesore ersrapayatarers 67° E. 
Top of hill south of centre village. 38° E. 
Near J. Farnum’s—high hill .... S.57° E. 
Salisbury,—S. part, top Bean’s hill..| Porph. gneiss....| S$. 22° E. 
South village syn cacsseuneeagas Montalban......] S.129 E. 
J. S. Morrill’s...... ee peterson S.15° E. 
Boscawen,—near village SE ecanssena S.27° E. 
Back of Fisherville.. SS. eolitenays 8.17° E. 
Kearsarge mountain,—top Dhessenciesciatevans Andalusite chic S. 46°-51° E. 
Top of clearing, north-west side. 36° 
Above Winslow house........4 ee gs 
‘At “ cot “ ‘ 
mile north of Winslow hous: iss S.41° E. 
orth side oe S. 76° E. 
caayoeierndesevae ea ee S. 46° E. 
South side o: se S. 719 E. 
Toll-gate of turnpike ss S. 51° E. 
West side, in Sutton ee S.11° E. 
Ragged mountain, Andover, top es S. 23° E. 
a S. 36° E 
“ce oe 
S.56°E 
Monadnock mountain. 
East edge of Jaffrey...........+ S. 11° E. 
A AERC EY ays unscascyseo six sesvety novel avaravanasdxstalaheietesat ce 
im Baker’s S. W. corner of Jaf- 
Andalusite gro’p.|  S.31° E. 
wae ee S. 46° E 
Fast and south-east sides o eB: ae S. 219° E 
pourh east side, local sliding .. te S$. 56° E 
ave aaa Asi ESE Te ge S. 219 E 
South: west of top..... : 68 8.519 E 
Somewhat lower down. AG S. 61° E 
Still lower..........2005 ce S. 51° E. 
New London,—near south line... Gneiss ......-... S.31° E 
George’s ‘mills......-2.0... ageiescie cl aepeees -| 8. 46° E. 
° 
Sutton,--south part.........eeee cues Porph. gneiss.... 8. 2 a and 
Mills.. wi . £6 


Nelson hill |. 
Newbury,—E. Nelson’s. 


Bends with Merrimack valley. 
Down a valley. 


W. Upham. 


Also south-east on a wall, and down hill 
to the south. 


Remarkably fine. 
All the way up the mountain. 


Also S. 75° E., or perhaps N. 75° W.; 
local. 


Slope to south. 


GLACIAL DRIFT. 


Courses of Strie—Continued. 


LOCALITY. ROCK. | eouue | : REMARKS. 
Bradford,—Baptist church .......... Porph. gneiss....| S. 25° E. 
North-east corner... MEISS: .ie:cieelors, as a W. Upham. 
Joppa? ves-caslsssiece Wewaeeeeitags ore S. 25° and S.| C. T. Jackson. 
20° E, 
Warner,—south side of Mink hills...| Porph. gneiss S. 269 E. 
South of Levi Bartlett’s... Gneiss ..... S. 21° E. 
Concord,—south foot of Horse h Montalban . Sooo i 
Mast Yard........2-0-0008 ot X S. 119 E, 
South of Rattlesnake hill Granite... S. 21° E. 
Phenix quarry.. Ie S.11° E. 
¥% mile north of Snow’: Ss ; pond. S$.17° E W. Upham 
Loudon,—x mile N. E. from village. |. e S$.15° E “ 
mile south-east from ‘‘Ridge’’. S. 25° E Gh 
orth-east Corner... ....eeeeveee oe § 40° E, Ge 
Hopkinton,—east part . “Ferrug. schist. . 10° E, 
Henniker,—village... Gneiss......6..-| S.21° E. 
Dunbarton y—Wedge—hill- to Lake gneiss sateen S. 21° E. 
School-house east of imball 
pond and further east—high.. Mone Pat ceaseless e 
S. H. Woodbury’s ......... 0005 iataveie S. 10° E. | W. Upham. 
Bow,—school-house, south corner.... ee S. 38° E. 
§.H. & J. H. Bartlett’s........ “ S. 21° E. 
Ths W'S! cscieisrescicene €£ S. 38° E. A downward slope. 
Hooksett,—near village.. Gneiss.. S, 26° E, 
Back from village Caen S. 189 E. 
Campbell’s hill.. lag Scspararnnsins Quartzite. S. 21° E. 
14 miles west Merrimack S. Pt..| Gneiss.... ff 
Manchester line, E. sige of river. se S. 169 E. 
Rowe’s old station. ef S. 41° E. 
Manchester,—fair ground .. fe S. 26° E. 
South-east part ie S$. 15° E 
Methodist church, Hallsville.. ere, S. 16° E. 
Amoskeag quarry... ... aieiatalarelenae Granite... ss 
local . Mica schist. N. 40° W. 
Same neighborhood... Gneiss ... S. 41° E. 
Bridge, Hanover street crossing. Be as 5S. 26° E. 
Outlet of Massabesic lake....... S. 21° E 
Candia,—top of hill, west part, J. 
METSON’S. 04. sssecensecen cece S. 31° E. 
Store, H. M. Eaton’s.. S. 26° E. 
East line ..,....50. S. 36° E. 
S. 21° E 
Ss. 28° a 
S S. 41° E. z 
Flint hill Quartzite... S. 36° E. Rene 
North of, at B. Dearborn’s. Mica schist. S. 31° E. 
South part...... rn ee ‘ S. 51° E. 
North of village... ee S. 31° E. 
Hill west of Flint.. iM S. 41° E. 
W. Titcomb’s....... ce S. 26° E. 
Epping,—D. Kennard’s . « S. 28° E. 
North line........... ce S. 219 E. 
A. Randlett’s . «6 S. 31° E. 
East of H. Bly’ S. ee S. 31° E 
Nottingham ............... ee a i S. 31° E 
West side of square, same hill.. of S. 56° E ’ 
¥% mile north-west from square. es S$. 20° E. W. Upham. 
cy mile south-east from square.. oF S. 20° E sf 
East of hotel.....cscceseeee a€ ar ee x| Intersecting. 
Fremont,—B. Poor’ Ss. Gneiss.. s° 31° E. 
Sanborn’s. “ S. 36° E. 
Exeter,—south-west of v lage Merrima’kschist.| S. 52° E This is usually covered by water. 
E. C. Sanborn’s Sienite.......... S. 24° E 
Stratham,—near B. Howe’s. Merrima’k schist. |S. 27° x 47° E.| Intersecting. 
Greenland »—North of church. . ee S. 27° E. 
Portsmouth y—powder magazine - «e S. 12° E. 
¥ mile west of Newcastle bridge” 
(south end of town) .........-. “ S. 37° E 
School-house, N. part of houses 
& mile from depot) taneiaysavareians 6 S. 32° E. 
Rye,—Sagamore house. : ss S. 52°F At ocean level. 
South of Sagamore river. . “se S.35° E 
Cnc part. 7 a “i: : 4 ee S. 42° E 
Seabrook,—north part of village. £8 S. 52° E. 5 
Newton -N. Gould? 3. a ay ae ee Same seen obscurely near post-office. 
‘Atkinson, —D. Noyes "s se S. 42° BE, 
South Kingston, hy, Collins’s... 221! Granite..........) S, 229° E 
VOL. II. 25 


190 SURFACE GEOLOGY. 
Courses of Strie—Continued. 
TRUE 
LOCALITIES. ROCK. | COURSE. REMARKS. 
Danville,—Wm. Bagley’s....... Merrima’k schist.] S. 32° E. 
Hampstead ,—J. E. Emerson’s.. “e S. 47° E 
Salem ,—village.....seeeeeeeee Gneiss.. eataayat _ 8.220 7 
Granite quarry «229x 729 Intersecting ; the first th t 
School-house. OO. si spasands S. 32° E. direction” eC eR ESS eae 
Derry, north part. Mica schist. S. 22° E. 
Below hotel . . S. 24° E. 
South part... ie S. 229 E. 
Chester,—W. S. True’s..... aS S. 51° E. 
H. Hazeltine’s, aul teP Gneiss .... S. 31° E. 
C. Chase’s......... Mica schist.. S. 29° E. Abundant. 
Auburn,—west of village... Gneiss .... S. 26° E. 
AL Siar, Seca Mica schist.. S. 21° E 
Pelham ,—near west line .s..ssseec0s Gneiss.... S. 21° E. 
Londonderry,—Mammoth road, N. : 
Mica schist.. S. 21° x 41° E.| Intersecting. 
ee . 21° E, 
ee S. 11° E. 
Hudson,—Mrs. Barrett’s, east part..| Gneiss .......... So Eee Intersecting. 
Nashua,—Merrimack river bridge. .-| Merrima’k schist.| S Te E 
Reservoir ..... cee ceeeeeee “ 
Merrimack ,—Souhegan village. . 
Amherst.. eee 
eccier G.B. Biasactis. 
part, near aisdell’ 
New Boston........- W. Upham. 


Coa enter ee acne 


Near Leach’s. 
Francestown,—north-west part 
Weare,—top of Mt. Misery.... 

so feet down east side.. 

‘Two places at south base of do.. 

Hodgdon’s soapstone quarry.. 

2% mile south-east of So. Weare 


church—A, L. Hadley’s 
Deering ,—north-west part...... 
West of village............. 


(eu alan eee north line.. 

Antrim,—west part .. 
Peterborough......... 
J. Mace’s, 3 miles east of village. 
ate: —near ‘‘ hard’? celts 
5 ona cited -east corner é 
West Wilton......... 
Temple,—top of jennie 
North of hotel.. 
Mason,—north-east corner 
‘West of centre....... 
Centre village . 
New Ipswich 
South end of Kidder mountain . 
Barrett Mountain range, near Ww. 
pies 

W. Young’ 
1 mile east ei Wilder village. 
Sharon 
Nelson,—Y{ mile south “of Munson- 


Sullivan ,—sou 
Marlborough,—% mile west of Pot- 
tersville....-+++- 

D. Field’s, 2 ie east of depot. 
Troy,—village.. 
Generally .. 
Surry,—Bald hill... 
Gilsum,—near village........05 
Marlow, 33 miles north ef mallsees 
mile south of dors 

Stodé ard,—west line.. 
Near. village... 
East line 

1 mile west of village nee 

1¥% miles west of Centre 

1 mile south of last. 
South-west corner... 


eeeelee 


“ 
“ce 


Gneiss ... 
« 


S. 21° E. 


‘|S. 18°-25° E, 


S.23° E, 
S. 21° E. 


Intersecting; the first course the most 
common. 
W. Upham. 


Fine example; moved up hill in North 
Branch valley. 

W. Upham. 

Both wall and floor surfaces striated. 


Polished smooth. 


C. T. Jackson. 


Ww. Upham. 


Ww. Upham. 


GLACIAL DRIFT, 


Courses of Strie—Continued. 


Igl 


TRUE 
LOCALITIES. | ROCK. COURSE. REMARKS. 
Harrisville ...... 0.000% «| Gneiss ..........| S.28° E. 
Dublin,—generally ..........s0200e+ Porph. gneiss....] S.27° E. C. T. Jackson. 
x mile N.W, of Monadnock lake.|.......0.5- Sraiaiovere S. 50° E. W. Upham, 
Y% mile south-east of W. uh 
ing’s..... ule latnraviove/isYo\ ele elnia'alusel| fatevavaroierererers ounVo¥oie +++] S. 50°-69° E. ee 
Keene,—north edge..........se0005 © S.15° E. 
Hill west of Village-—West Mibiis-ccoore’s S.20° E. 
West Keene, top of hill—Con- 
necticut river water-shed... S.15° E 
Chesterfield,—Bear hill...... on S. 10° W 
x mile south of Factory village «. S. 10° E. W. Upham, 
1 mile east of Centre ........... S. 209 W ce 
North of T. A. Stoddard’s.....-) 0! sees S. 10° W <e 
Winchester,—4 miles N. N. W. from «S 
Villa gets iceeeverntetaisveecerstets +eese+| Porph, gneiss.... S. 5° E. 
Westmoreland,— Hill” village. Mica schist...... 5° W. $s 
% mile east of E, W. depot.. Gneiss ..........| 5. 10° E. Se 
Walpole,—% mile couitliceact of S. 
HE Nos 23s neci celiaiescs ecayeises: S.15° E. oe 
2 miles east of ‘villag. Cannon S.15° W. ne 
Alstead,—z mile north or E. Alstead. «-| S, 10° E. fe 
Hinsdale and neighborhood .......+. Gneiss 2201001 S. 10° W. F 
Dep otiig sisisisieccaraivinsercsvrwsaiereioiers «e+! Micaschist...... s it x 8.) Intersecting. 
North-west base of Stony mt. Mica schist. S.2°E C. T. Jackson. 
Richmond ,—east part ... Gneiss . S. 25° E 
Soapstone bed........sseeeee a South 
Fitzwilliam,—z mile east of village..| G i «| S.20° E 
Quarry hill, south of depot... Granite. »| S. 10° E Up hill. 
Rindge,—East Rindge... .... cc. cece [esee sees cece soos]! S. 75° E W. Upham. 
Washington,—north part... Porph. gneiss. .|S. 21° x 41° E.| Intersecting. 
Lovell’s mountain—top.,... aeeel §, 36° EB, End of ledge embossed. 
x mile south of Miller pond. Gneiss . aseniatscarsiaia|’ (Sy G00 Es, . Upham. 
South of Ashuelot pond. siete ita se an 
West BEY Syacaicisrists Porph ‘gneiss. $. 25° E ee 
Lempster,—Lempster mount’ rae Mica schist......] S. 41° E. Uncommonly fine. 
West side do...... ee eeeaiee S. 21° E. 
Acworth, ,—village . . a oie S.8° E The same 1 mile west. 
Charlestown,—village. Cos oi South 


East part.....seccsssseccee 
Near north-west Acworth.. 
Unity,—south of Neal mine.. 


East Unity. 
Claremont,—aquedu 
of Bible hill.. 

Top of Bible hill. 


Below top....scccecsseccesseece 


Most common about village...... 
xr mile suterash from Clare- 
mont village. . 

4 mile north do. 
Barber mountain, 


ee 
side, near J. Woodell’s . 
Barber mountain—top 
A. Brown’s, W. Clark’s, and 
south of N. Stone’s 
S. Nott’s.... 


L. Farnsworth’s.. 


West of C. Dean’s... 

Cornish,—west flank of Croydon 

mountain—Hilliard’s.... 

4 miles south-west from ‘‘Flat’’.. 
Goshen,—south part...... icin 

ate ve aoe ea of Croydon 


pon 

1 mile east of do.. 
Springfield,—Mud pond fe 
Je Currier’s—ridge.. alasataiarnninareieneie 


eae 


Huronian.... 
«e 


Mica schist...... 


W. Upham. 
Ww. Upham. 


Noticed more fully in text, 


WwW. Upham. 


.| Intersecting, and irregular below. 


.| Intersecting; first cut by second. 


W. Upham. 


Boulders in a line, S. 40° E. 
W. Upham. 


“ 
Ta 
“ 


Very fine. 
Numerous. 


192 


SURFACE GEOLOGY. 


Courses of Strie—Continued. 


Mica quarry—Ruggles’s 


LOCALITIES. ROCK. SaUnee REMARKS. 
Ridge. Sieaiareys wiles casting Gneiss .......- «| S.29° EL 
1% miles north-west of West 
Springfield...... iat aera de aio ahs S. 6° E. 
Station pond ee fis sesso oe 37° E. 
South line next eereee 's mill....| Andalusite schist 31° E. 
SA, Melvin’ Si s.siajsse:dieie:sisiereisjele:biaie:s|) MAMENSS 2 os gjaiajere: d:aicys 26° E, Top. of hill near, S. 20° E., on quartz 
Grafton,.......+00.. W ielecehs es 25° KE. veins beautifully smooth, 
21° E, 


Miners’ house—Ruggles’s. 
Hill north..........06 
Outlet of Tewsbury pond. 
North end of do...... 
Melvin’s mica quarry. 
Grafton,—school-house No. 3. 
C. Prescott’s—hill-top.... 
Hill west of Prescott’s. . 
V. W. Powell’s, west side 
Near top of Alger hill... .. 
Giles’s pinnacle, west side 


Orange,—summit........... 
Between school- ‘house No. 1 ‘and 
church . Siete aft Sete ate aierets 
Andrews’s mill...... Seve 


Hoyt hill, south of quarry. . 
mica quarry, N. ‘side. 
Top of Shad hill.. wy, 
seas e mile west of Orange : sum- 
Hill eee ‘of East Canaan. 
North-east of ae Ss poms 
Sawyer’s hill.. 
South edge.. 
North line..... 


ake.. 
‘West side of ridge, near W. Tine. 
Lily ponds .i30.2 sic scessiesisie iiaaeiesaia 


West of do., % mile.. 


South-west base of tious hill. 
East hill, east side 
Lebanon,—east edge of village.. 
West of East Lebanon...... 
West of B. Melee ee , 


School-house by O. S. 
Between A, Freeman’s and H. 
Grant’s . 
Hanover,—near SH! » Hayes’: S hill. 
West part of do 
North part of do.. 
Hill south from S. Hayes’ 'S 
Near town line to south.. : 
A knob west....seeseeeeee . 
Copper mine, ‘ Rudsborough’”. an 
Mink brook, near Held. conglom- 
erate.. 
Enfield side 
near school-house.....- 
W. K. Covell, hill-top, N. part. c 
Observatory Bill... see ees 
Moose mountain........ 
Lyme,—below I. P. Holt’ s, “down 
valley from East Lyme to 
Canaan. 
A. Blood’: s, “down ‘valley from 
East Lyme to Canaan....... c 
West of I, F. Clark’s... % 
L. Conant’ Ss, east’ Batts ats 
West of S. Ames’s.., 
Orford »—top of Mt. Cuba: 
West SIGs. cierseanes 
Top of Sunday mount: 
Few rods on south slope. ‘ 
Cheese factory.. 
Bass Loar top, 


Gneiss .. 
« 


Granite.. 
Gneiss .. aed 
Mica schist... 


Andalusite schist. 
“ce 


Lake gneiss.. 


Cois slates... 
Quartzite.. 


. Mica schist. . 
Gneiss .... 
« 


“ 


“ce 
“ec 


“ce 
steeee 
ee 


wn 
1a) 


Se ee Ss. 
Quartzite.. 21°R 
Slate.... S.51° E 

Se 8. 

ee S. x 21° E, 

Co hiteiayers Ss. 
Mica schist...... Ss. 
Cois slate........] S. 7° EB 
Clay slate.. Ss. 

Se 8.31° E 

oars Ss. 

“ ee 
Quartzite........]S. & S. 219 E, 
Mica schist.. » S$. 9° W. 
Slates.....cseeeee]! S. 51° E. 
Gneiss ..........| S.19° E. 
Mica schist......] S.11° E. 
Hornblende sch’t. Ss. 

Seg se aeeeerceee] §, 38° E. 
Gneiss..........]) S. 32° E 

CS asics oiaierartinys S. 26° E. 

fs S. 26° E, 

ee S.21° E, 
oieie dare S. 11° E. 
Quartzite. S. 289 E, 
Staurolite schist.| S.37° E. 
Mica schist...... S. 11° W. 

sages S. 3° W. 
ba a6 S. 2° KE. 
Me seceee{ S$. 8° W, 
re eseseel S. 14° E, 


"O 
1 
U9 
a 
ro) 
ical 


a 
fo) 
om 
» 
=] 
a 


[ae Poe ala fine embossment; val- 


ley movement. 


Observed in two places. 


Transversely up hill. 
Grooves. 
Abundant. 


Striz visible for 50 feet and furrows. 
Very fine, 


Intersecting. 


Up hill, and east side of rocky valley. 


On ledges close by course is S. 7° E. 


Intersecting. 


Abundant. 


Embossed ledges 40 feet long. 
Latter on lee side of first ; do not inter- 
sect, 


Unusual ; local (?). 


Obscure. 
J. H. Huntington. 


Abundant, 


Very fine. 


GLACIAL DRIFT. 193 


Courses of Strie—Continued. 


' TRUE KS, 
LOCALITIES, | ROCK. COURSE. REMARKS 
Bridgewater. . sseeeee| Montalban...... S. 329 E. Down valley. 
Dorchester,—south part. Gneiss .... -| §. 12° E 
Wright’s hotel ....... Be Bs i E. 
2 miles south of village., Se aiepaies -| S.179 E. 
Piermont,—east part...... Hornb. schist....} 5.429 E. 
¥y% mile west......-... aad si S. 24° E. 
est part, near Conn. river..... Huronian 7 -15e E. , 
xz mile east of village............| Mica schist...... S. ae x 5.| Intersecting. 
Near whetstone quarry .. ae S.19° E. On large hill. 
East part of town..... eo S. 20° E. , 
North of Tarlton pond. Gneiss ...... S. 18° W. Near foot of Webster Slide mountain. 
Peaked Hill range to south. -| Micaschist......| S, 16° E, 
Cross hill... ..... keneyegoFaforetete sees] Quartzite........ S. 42° E. C. T. Jackson. 


Str_# in STATES conTIGUous TO NEw HampsuirE. 


. TRUE 
LOCALITIES. ROCK. COURSE. REMARKS. 
VERMONT. 
Norwich, Vt.,—east of school-house 
. o. 2, and also below Dut- 
ton’s, a mile distant........... Clay slate... S. 26° E. Down a valley tributary to Conn. 
“ DD. H. Bragg’s, Distict No. 2... ee F Ss. Normal course again, west of the local 
; one above. 
Gregg’s hill........-.045 Calc. micaschist.| S. 8° E. Numerous. 
Weathersfield,—near Con Huronian........ S.49 W. 
South of do.......eeeeeee Slate... s. 
Opposite North Charlestown....} “ ....., 
Warren,—Summit to Roxbury......| Huronian.. Intersecting. 
Near do........ OO semen Senn * 
Sherburne.......eeeeceee ve seneceeee! Gneiss .... Down hill. 
Windsor,—top of Mt. Ascutney .....| Sienite.. 
¥% way down..... evenee aes Ss 3 
At dam near village. Mica schist.. S. 30° E. The common direction. 
erent “ «6, a N. 70° E. | Unusual direction, and local. 
Bradford,—south-east corner........| Huronian.. Ss. 
Peacham,—rz mile west of “‘Corner’’.| Granite... S. 13° E. 
Canaan ,—z miles west of Conn. river.} Mica schist......| S 34° E 
OxssERVATIONS TAKEN BY GEOLOGI- 
CAL SuRVEY. 
Waterbury,—east part. Fonietiveaiw| Spee By 
Stowe,—central parts Se as « S. 35° EB 
Elmore...... ce S,24°-38° E. 
Woodbury.......00e+ ce -|S.12°-S.42° E.| The observations taken in these several 
Barnet and Waterford. se S. 7°-12° E. towns were abundant, and I have giv- 
West Concord.... BG S. 22° FE. en the extremes, it being unnecessary 
East Concord. * seeeal S.2° Rh, to present all the details of locality 
Kirby....... Slate vsissarccnsscies S.20° E. and variability. 
Lunenburg... Huronian.......| 5 3 ESS 
D 2 re 
Guildhall. «saw S.7° E. 
Granby ... Mica schist... S, 13°-33° E. 
Victory ... eG ete S$. 23° E 
Maidstone. Mica schist.. S. 239-419 E. 
Canaan ... ee wea S. 130-259 E 
Sheffield..... Calc. mica sc! S.4° & 
Glover ...... ee S.7° E. 
Greensborough.. q 
Craftsbury.. S. 
aovell 0 
Wolcott... wa R i 
Boe Bask. 2 ; uns up Lamoille valley, 
Morristown ......6. 
Johnson ee s go-go E. | Up Lamoille vall 
Ce ee + 42 « ey. 
Wee sd satetevetaistoherebelsteraye alsreretetaraiate avags ch | gsie S, 8° W. Normal, course. me 


194 


SURFACE GEOLOGY. 


Courses of Strie—Continued. 


LOCALITIES. | ROCK. an REMARKS. 
Mansfield mountain.........--++ sees] Gneiss ...5-+2+6-/5. 22° E. and 
Jay peak ...cccceecssncncssecnee re 
Camel’s Hump 
POY eihsaliciei ovatarsieioiesdiaua’siece 
Salem .......cecceseerer 
Brownington .....-ssseeeeee 
Brighton .....eseeeeceeevees 
Randolph ..... 
Roxbury 
Newbury 
Bradford 
Fairlee. .. Clay slate 
Thetford... Mica schist. S.12° E. 
Chester.... neiss -| 5. 42° E. 
Rockingham........cseeeeee Clay slate. «+| S, 20-119 E, 
Putney....... Sf oe ++] S. 100-29 W 
Dummerston......+ iP. 3 «| _ S.10° E 
Brattleborough ......+-+++0+ re S. 10°-18° E 
Vernon...... Seren eee. ae S. 49-229 E 
Guilford... cece cece cece ceeeeeeceees BED" saraicjataiece S. 109-159 E, 
QUEBEC 
Aukland ....sseeeeeeee s mena +++.| Argillac, schist..] S. 24° E. . 
Gould... Micaischist..... S$ Ger. | J. H. Huntington. 
Newport .. Cale. micaschist.} S.34° E 
oe Sena i Huronian .,.....] S. 
ULtON .. eae 5S: Ss. 

Sutton Flats. ad S. W. E. Logan. 
Orford....... cesses eeeescenee oe Ss. ‘i 
Brome,—Canada mine ae 

East Canada mine as 

Jerry Davis’ Siminisenesigaeree cies we Se 
Potton,—top of ridge south of “Owl's 

ead is as sfetasnsn cesses Dieta ait sf 
Maing. 
Portland,—north-west from custom- 
OUSONiseKs aaa tet ee gpa sani S. 23° E. Very fine. 

Portland hospital..... : S. 3° E. 
SAC Osco sayoiesa sisssel ois crolsieupialesoneiaud. onoiscece Cambrian | S. 16° E. 
Lebanon post-office.....+-ese00 Andalusite schist.|S. 479-529 E. 

East of Lord’s....cseeer cece cere ee .47° E, Very fine. 
Springvale (Sanford) .. Mica schist..... «| S.42° E. 
Denmark village...........-++ seaeee| Gneiss . 


1m. north of Pinhook, pene iets 
Bridgeton, north-west ” of village.. 
Standish, yailroad lake station 
Top of Mt. Pleasant 
West side, near top 
Androscoggin valley, north part of 
t. Ephraim ete 
Church in Gilead, north side........ 
Base of Tumbledown-Dick........ aie 
East line of Gilead. z 
oo hill, Beth 
New: ote 
Falls near : Poplar 
Just above do. 
East line of Grafton . 
Grafton notch—highest point. . 
Upton,—D. C. na Seven 
O. H. Abbott’s.. 
Near East B. hill. 
Opposite Dartmouth College grant.. <i 
Andover N. soon n’r Dunn’s notch. 
A. Pratt’s. 
South line... 
N.S. Lufkin’s . 
pO We Shove, sie. encicreretverMaieisleinss alt 
Rangely ,—top of Bald mountain 


Bethel, —opposite Hanover........ i 


Near Songo pond.....eseeeseeee 
Lovell,—No. 4 Corners.. a 
Fryeburg,—Near Mt. Tom.. 


ee 
“ 


Gneiss ... 
Montalban . 
te 


Granite.......--+ 
Gneiss .......... 
Mica got Been 
“oe : 
Granite 
Gneiss . 
« 

ee 


Granite 


Androscoggin Valley marks more fully 
described in text. 


Down Bear River valley. 


Valley movement down the Magallo- 
way. 


Valley movement. 


Curving with valley. 
J Bish nccon a 


GLACIAL DRIFT. 195 


Courses of Strie—Continued, 


LOCALITIES. | ROCK. | Gane, REMARKS. 
Broomfield,—M. McLucas’s.....-..| Granite... S. 18° W. 
Hiram,—north west of Spectacle 
ond.. Gneiss ....--60-. S.12° E. 
Cornish, 
lage. Montalban. S. 22° E 
Standish,—west edge SE rsyapaarenls Ss. 


Limington,—W,. Chick 
of hill 5 
F. Strout’s, top of hi 
Limerick village ........ceeeeeeeeeee 
Alfred,—¥% mile north of N. Alfred, . 
J. Roberts’s.... seeeseeee isaienaihes 
South Berwick..........-..+.. sijavaneda ave 
Danville junction, G. T. R.........+ 
Saco slate quarry.......eceeeeen ones 


Cape Elizabeth,—T. Seavey’s....... 


Several examples of this acai di- 
rection occur for 14 mile. 


On wall—well shown. 


i] S. 8° W. course the most common. 


Bdge 208 « iereccsteraawsrsieceie esiwlareananns. 
Peak’s id. —Evergreen landing .... 
Bast Sides sic iisscresg steaeis ceases 


Cape Elizabeth,—Rail schist locality. 
Deering,—hospital......--.esseeeeee 


MAasSACHUSETTS. 

Northfield,—very near New Hamp...| Micaschist......] S. 8° W. 
New Salem,—top of hill .........++5 Gneiss .........-] 5S. 12° W. 
South Royalston.........ceeeeee eens OS caxaveratai evens S. 10? E. 
Salisbury,—Eastern Railroad cross- 

ing north of village...........+ Sienite ........ weil) Sp rO 
Bernardston,—top of West mountain.| Slate..........+ S. 5° a Ss. 

10' 

Newbury,—several places...........] Sienite....,..005 S. E. According to Massachusetts report. 


Remarks, The table contains everything needful for explanation, save where more 
than one set of striz is mentioned. When two or more sets occur in immediate con- 
tiguity, not crossing each other, the fact is indicated by the use of the conjunction azd; 
when two or more intersect each other, the letter x is employed, and the fact is usually 
stated in the column of remarks. 

The embossment of certain ledges in Pittsburg and Shelburne is peculiar, in that 
the lower part of the rock below the smoothed surface is rough. The ice may not have 
struck the lower part of the ledge; or, in some cases, the subsequent disintegration 
may have removed the lower part, leaving it as rough as the lee side. The Pittsburg 
examples may be eight or ten feet high, with a roughness of three feet, partly to be 
accounted for by the easy removal of rock on account of the presence of easterly dip- 
ping jointed planes. The Shelburne example is more striking. It is about a mile 
below the station. The ledge is about 30 feet high and 75 long, and the roughness 
below the striated part as much as 6 feet. The irregularities upon the lee side begin 
at the very top of the eminence. The end struck is 4o feet wide, tapering to a blunt 
point, where the smoothed appearance disappears; and the inclination of the stoss 
slope towards the north-west is about 50°. 

Wall and floor surfaces are alluded to. This is because some writers insist that the 
former method of sculpture is never seen with iceberg action, being produced only by 
a glacier. As noted above, this species of moulding is very common. 


196 SURFACE GEOLOGY. 


The striz about Bible hill in Claremont need further mention. This hill rises about 
350 feet above the plain of the village at its northern base. What is supposed to be 
the normal direction is about S.12° W., which occurs commonly west of the summit of 
the hill for two or three miles, reaching beyond the Connecticut. North of the village, 
it is S. 15° E.; among the houses, S. 41° E.; and on the east side of the hill, S. 23°-25° 
E., in a valley leading to Unity. On the south slope of Green mountain, east of the 
village, are intersections of the almost east course with that of about S. 12° E. On 
the westerly side of the top of Bible hill the most common course is S. 6° E. with S. 
25° E. This is half a mile east from Brown's, Clark’s, and Stone’s, where the westerly 
course has been noted. We now proceed three fourths of a mile north-east to the 
‘¢Flat Top,” a spur of the hill, with scarcely any depression between. At the com- 
mencement, where the north-east slope begins, are striz S. 57° E. pointing back to 
Little Ascutney, and crossing others S.1° W. Next are some S. 46° E., pointing to 
Ascutney, apparently marked on the lee side of strie pointing S. 1° W. to S. 1° E. 
Another ledge has striz S. 46° E. crossed by others S. 1° E.; then S. 16° E. crossed 
by S. 41° E. and S. 51° E., the middle one the most common. Another ledge shows, 
in a narrow compass, the courses S. 21°, 36° 41°, and 57° E. Where the courses are so 
numerous, there is a marked tendency to irregularity; the striae do not preserve their 
parallelism. A change of ten or fifteen degrees in direction will occur in a distance 
of less than a yard. Flat Top hill shows more of the irregularities than the highest 
summit to the south-west. Near the aqueduct, at the base of Flat Top, the course is 
S.17° E. The impression was acquired at our visit that the south-east course cut 
those running southerly. 

This is the most remarkable mingling of strie I have ever met with. It is obvious 
that the field was crossed by the ice proceeding south-east and south, or from Ascutney, 
and down the Connecticut. The first were also occasionally deflected still more to the 
east by the large valley of Sugar river leading easterly to Sunapee lake. Some of the 
intermediate courses might have been caused by the meeting of the two masses of ice 
struggling to advance in different directions. Boulders from Mt. Ascutney are com- 
mon to the north-east and east of Bible hill. The locality needs further exploration. 

A few other interesting localities will be mentioned next before we attempt to draw 
the legitimate conclusions authorized by the list of stria. 


Mr. Monapnock. 


This mountain possesses a conical shape, rising about 2,000 feet from 
a comparatively level country, the elevation of the plain being 1,000 feet 
above the sea. Its composition causes the striz and embossment to be 
well preserved, while its isolated position illustrates one peculiarity of 
the drift-action. My father first described it in the Proceedings of the 
American Association of Geologists and Naturalists, in 1842, in the geol- 


GLACIAL DRIFT. 197 


ogy of Massachusetts, and in his text-book. He says of it,—“ From top 
to bottom it has been scarified on its northern and western sides. On 
its lower parts, especially on the south-west side, the striae run about N. 
W. and S. E., by the magnetic needle, as they do in the country around 
the mountain; but, when we approach its top, the course changes to N. 
10° W. and S. 10° E. Other strize are seen here on steeper slopes, both 
northern and southern, than I have found elsewhere.” 

The observations given in the table were mostly taken in 1871. It 
would appear that the common direction in the vicinity of Monadnock 
is about S. 12° E., the towns north showing a few degrees additional of 
easting, while the mountain itself, from the lake to the south-west corner 
of Jaffrey, about eight miles, exhibits, on its north-west flank and southern 
edge, the south-east course. After looking over the whole area, one sees 
that the ice coming from the north and west of north struck the moun- 
tain and clung to it closely, so much so as to run much more easterly on 
the south edge than elsewhere. Over the region to the south-east all 
trace of this easting is lost, the striz in Jaffrey running S. 11° E., much 
like those of Troy and Marlborough. I have not explored the east side 
of the mountain; it is mostly covered by trees. Hence it is impossible 
to decide upon the value of Mr. Wheelock’s theory, from present explora- 
tions. I understand his view to be, that Monadnock was an island in a 
sea full of icebergs, which struck equally strong upon both the north-west 
and south-east sides. There is certainly a dearth of striated ledges upon 
the south-east side, while even the earth has been largely removed from 
the north-west flank, so mighty has been the planishment of the rock. 
The striz on the south-east side should all point south-westerly, if the 
summit were an island scarified on both sides by icebergs. Mr. Whee- 
lock’s paper is a very valuable one; and that part which relates to strize 
is herewith reproduced. 


Strie on Mt. Monadnock.* Waving, in the last three years, spent many days in 
studying the striz upon Mt. Monadnock, the writer is unwilling that the results of his 
observations should be lost for want of record, especially as they seem to have an im- 
portant bearing upon unsettled questions of surface geology. This mountain is pecul- 
iarly favorable to such study. Its long spurs radiating from a central elevation, though 


* American Naturalist, vol, vii, 1873. 


VOL. 111. 26 


198 SURFACE GEOLOGY. 


less regular than the points of a star, yet present to four points of the compass 
long ranges of bare rocks, which have recorded the markings of the ice-period, with all 
their variations of direction, and furnish a lesson not to be found, perhaps, in any other 
locality. To understand fully the meaning of the evidence herein detailed, it is neces- 
sary to have a clear idea of the relative bearing and position of these radiating ridges 
or spurs. 

For the sake of clearness of description, we will suppose the principal ridge, which 
runs N. 25° E., to be straight, and to be four miles long. This ridge was an uplift, 
sloping towards the west, and presenting its broken and precipitous face towards the 
east. Itis like a dam set obliquely across the current of the northern drift, and its 
serrated edge rises from 1,500 to 2,000 feet above the surrounding country, growing 
higher from each end to its central parts. If we suppose a section of this range near 
the centre to be pushed some fifty rods further west, and elevated to the height of 3,280 
feet, we shall have the summit of Monadnock. A short spur projects west of the sum- 
mit about a mile, and divides into two branches. These we will call the west and 
north-west spurs. The two ends of the dam we will call the north and south spurs; 
these, with the western spur and its north-west fork, complete the outline of the moun- 
tain, making four radii. 

Numerous observations of the direction of drift striz made in the adjoining towns 
show very general uniformity. They have a range of not more than 15°, varying 15° 
west of north to north and south. On the summit of Monadnock the direction varies 
within the same limits. Only one set of strize was noted there as 5° east of north. So, 
too, following along the north-east spur, there is no change in the striz so long as the 
altitude remains the same. The crest is all naked rock for two and a half or three 
miles, and frequent observations can be made. Just as fast as the ridge falls off in 
height, the stria gain a more westerly direction, becoming 15°, 20°, and 25° west of 
north; where the rocky ridge terminates and is succeeded by open pastures, 30°, and 
in many places 40°, were noted as common. Appearances indicated a local deflection 
of a current around the northern end of this long dam. 

Although a special expedition was made to what was called the north-west spur, the 
lower portion of it was so much covered with drift that few exposed places could be 
found. Some five or six, however, and all that were noted, showed strie N. 25° E. 
All the higher portions of the ridge were striated like the summit and the ridge before 
described. 

Another day’s expedition was made to the west spur. Standing on the crest of this 
lofty ridge, and looking towards the south, the view is unobstructed to the horizon. 
The striz all along this ridge are innumerable, and all north and south. There is no 
opposing ridge near, to lead one to expect south of this a change in the stria. On the 
contrary, there is every facility for the drift current after passing this ridge to continue 
on ina straight course. The southern spur is a mile or more off on our left, and pre- 
sents a high opposing barrier towards the south-east, but none towards the south. Why 
should the drift current, after passing this ridge, suddenly turn towards the east and 


GLACIAL DRIFT. 199 


climb the steep and lofty barrier of the south spur? Nevertheless, there are indications 
of just such a change as this. 

If we place one foot of a pair of imaginary compasses on the summit of Mt. Monad- 
nock, and with the other strike a curve from the west spur to the south spur, we shall 
hardly have made a more complete change of direction from one spur to the other than 
is indicated by the striae in the short space of a mile and a half. It is difficult to pass 
over all parts of the valley between these two spurs, the upper portion of it being ex- 
tremely craggy or uneven. It is better to go down to the open pastures at the base of 
the mountain. Beginning at the foot of the western spur, and skirting the base of the 
mountain towards the east, the first thing to excite attention is the immense number of 
boulders. They exceed in multitude any other deposit about the mountain, but form 
no part of its talus, which does not fall on this side. They seem to be in some way 
connected with the change of the drift current, which began at this place, and with the 
position of the ridge, under the lee side of which they lie. Passing through these boul- 
ders, which continue for half a mile or more, we come to the first bare ledges. These 
are marked with striae N. 20° W. These are soon succeeded by others, 30°, 40°, and 
50° west of north. They may not all occur in regular order. On some ledges there 
are two or three sets of striz of different angles. Proceeding a mile and a half, we 
arrive at the easterly slope of the south spur, near the Mountain house. The road to 
this house was built north and south on sloping ground; and for half a mile the fresh 
surface of the rock was in many places exposed to view. It is everywhere scratched 
and polished. These scratches vary from 50° to 60°, and 70° west of north. Climb- 
ing the slope of the ridge, everywhere the exposed prominences of rock are embossed 
in the same direction. Arriving at the crest of the ridge, it is everywhere serrated 
and uneven. 

On this height we again overlook the whole country. Here, on the narrow crest of 
the ridge, the striz are very generally N. 40° or 45° W. In one place an angular 
trough, perhaps 20 feet long and 6 feet deep, runs across the crest. In this are long, 
continuous striz due east and west. They appear to be exceptional, and suggest the 
idea that this shallow trough had been able to control and change the direction of the 
striating force. Standing on this ridge, and looking towards the east, we see that the 
mountain on this side is very precipitous, and that probably there are no striz on its 
broken surface. Higher up the mountain, within a thousand feet of the summit, the 
strie are 35° and 30° west of north; lower down, at the extremity of the south spur, 
the end of the long dam, they vary from 40° to 25° west of north. What kind of striz 
should we expect to find under the lee of this four-mile breakwater? Another expedi- 
tion and another day were required to answer this question. The country east of the 
four-mile ridge is mostly wooded and difficult to traverse. The rock is mostly covered 
by drift. Beginning at the south end, and travelling north, no striz were found until 
two thirds of the distance had been passed over. Curiosity was at last gratified by 
finding large, flat surfaces of naked rock, scored all over with long parallel lines much 
better preserved than those on less wooded and more exposed parts of the mountain. 


200 SURFACE GEOLOGY. 


It would be difficult to decide what was their prevailing direction. Multitudes ran due 
east and west; some few, north and south; some, N. 10° W.; some, N. 10° E.; many, 
N. 70° and 80° W.; many, N. 70° and 80° E. No theory of mountain slides could 
explain this remarkable scratching: the situation seemed to forbid such an explanation. 
These observations were made on many different ledges, but all of them within half a 
mile of each other, and within a mile of the north end of the ridge. When a rapid 
stream, with a current of three miles an hour, passes a rock in its bed, water will flow 
around the rock and meet on its lower side. Do not these irregular striz indicate a 
changeable and eddying current inconsistent with the motion of a glacier? 


Mrs. KEARSARGE AND RAGGED. 


Mts. Kearsarge and Ragged rise abruptly from a comparatively level 
country, like Monadnock, but, being situated near each other, not quite 
six miles apart, the conditions gave rise to a different motion of the ice. 
Ragged is not so completely isolated as Kearsarge, being connected with 
mountains in the north part of Andover. Sutton, Salisbury, and Hill 
have the average direction for striae of about S. 12° E., while in Warner 
there are several degrees more of easting. The parts of Wilmot and 
New London next to Kearsarge do not show striated ledges. Starting 
from Warner, on the south, the table shows the change from S, 20° E. to 
as high as S. 76° E,, it being nearly south-east on the summit. On fol- 
lowing down the north side, the easting falls off to S. 36° E. at the Wins- 
low house, but reaches N. 67° E. in the valley by Potter Place. Similar 
figures continue all the way to the top of Ragged mountain from the 
southern base. At the last house,—1,100 feet (450 feet above Potter 
Place),—the striz run S, 71° E.; at 1,340 feet elevation, S. 31° E.; at 
1,650 feet, S. 46° E.; at 1,775 feet, S. 23° E.; the same for 200 feet fur- 
ther; at 2,000 feet, S. 36° E.; at 2,100 feet, S. 23° E.and S.51° E. Here 
the embossed ledges are numerous, while the striz are much worn. The 
S. 50° E. course appears higher up, but not on the summit or at the sig- 
nal, 2,256 feet, where the direction S. 23° E. is to be seen. We have, 
therefore, two well marked directions, very much as on Monadnock, the 
S. 23° E. course appearing by itself on the summit, while the south-east 
lines show themselves all the way down the south slope. 

Considerations will be presented soon, showing that there was some- 
what of a local or valley movement of ice down the Blackwater river. It 
may be that the greater eastings of the striae about Potter Place are 


GLACIAL DRIFT. 201 


due to other causes than the mere influence of the two mountains, so that 
we cannot strongly insist that the easterly movement of the stria from 
Hill to Warner is entirely due to the presence of the two mountains. 
The only feature where this case is unlike Monadnock, is the easting at 
the base of the mountain, which we see may have been produced by an 
independent movement. 

Other Mountains similarly Striated. Of other mountains similarly 
situated, some exhibit the same kind of ice-action. Mt. Gunstock has 
S. 62° E. strize on top, and the S. 32°-35° E. course on the east side, bor- 
dering Lake Winnipiseogee. Mt. Lovell in Washington shows the direc- 
tion S. 36° E. on the summit, while it is commonly S., 21° E. in the north 
part of the town, though crossed by a set running S. 41° E. Lempster 
mountain summit shows the direction S. 41° E., and it is S. 21° E. on the 
west side. On Mt. Cuba we find S. 28° E. and S. 37” E,, while it is com- 
monly west of south in Orford on the west, and S, 22° E. in Wentworth. 
Moose mountain in Hanover shows S. 38° E. on its summit, while the 
course is south on the western side, and S. 19° E. on the Enfield side. 
There is a south-east course in the middle and south-east part of Hano- 
ver, which may have some connection with these movements on the ele- 
vated summits. Sunapee mountain would be expected to agree with its 
neighbors, but no observations of striz have been made there. Mt. As- 
cutney, just out of the state, exhibits phenomena worthy of mention here. 
This has the same altitude with Mt. Monadnock, while the land about it 
is more uneven, averaging less than around the Cheshire peak. Owing 
to the rapid disintegration of the rock, strize are scarce, and perhaps the 
few examples discovered should not be taken as truthfully representing 
the general courses. The very summit showed a due south course. About 
300 feet lower down, on the north-east side of the mountain, following 
the Windsor path, are striz running due east, or N. 80° E. They rest 
upon a wall inclined 70° N., and point down the mountain towards the 
south part of Cornish. Others in the neighborhood run S. 20° W. About 
two thirds of the way down are other distinct strie running S. 10° E,; 
and no others were seen on the mountain proper. On reaching the dam 
over Mill brook, west of Windsor village, the course S. 30° E. is seen, 
and a few N. 70° E., a very unusual direction, supposed to have been 
the result of some local disturbance. In Weathersfield and Claremont, 


202 SURFACE GEOLOGY. 


along the river, the usual course is west of south. Observations west of 
Ascutney are wanting. It appears, therefore, that the observations are 
not ample enough to say positively, though it is probable, that the stria- 
tion of Ascutney is like that of Monadnock. 

Mt. Pleasant, in Denmark, Me., may also be mentioned as allied to 
Monadnock. South of the mountain the course is S. 12° E.; east, it is 
S. 20° E.; north, it is S. 8° E,, while one observation in Fryeburg, to the 
west, reaches S. 32° E. On the summit the strie run S. 41° E. On the 
north-west side, following down the path, good examples occur of the 
course S. 31°-33° E. Lower down are others less satisfactory, running 
S. 52° E. Not far from the Half-way house are some seemingly local, 
running west down the hill. 

Certain other elevations in the state, with topographical surroundings 
like Monadnock, show little difference in the direction on the summit 
and the neighboring plain. Such are the Moose mountains in Brookfield 
and Middleton, Teneriffe in Milton, New Durham ridge, Catamount hill 
in Pittsfield, Blue hills in Strafford, Saddleback in Northwood, Temple 
mountain, Barrett mountain in New Ipswich, etc. Crotched mountain in 
Francestown, Ossipee in Carroll county, and Pawtuckaway in Notting- 
ham, have not been studied, while Green mountain, Effingham, is too 
thoroughly disintegrated to preserve any markings. 


PREDOMINANT CouRSES OF STRLA. 


The Vermont geological report states that the striae may be classed in 
three divisions,—those pointing to the south-west, south, and south-east, 
the first being the least common. The south-west course is much more 
infrequent in New Hampshire, while the south-east direction is more 
prevalent than in Vermont. A sketch map in Volume I (p. 542) shows 
the general relations of these three kinds of movement for both states. 
Many of the striz are so disposed that they may be believed to be the 
result of valley movements. In our researches we have constantly asked, 
How much do topographical features influence the course of the striae? 
The replies forced upon us insist that a portion of the directions is due 
to topographical features, while others—the majority—pursue a fixed 
course, in total disregard for all obstacles. The first we have styled val- 
ley movements. A part of these are distinguishable from the others 


GLACIAL DRIFT, 203 


where the course of the valley corresponds with that of the neighboring 
striae. 

The south-east courses commonly occur upon the most elevated moun- 
tains, both in New Hampshire and Vermont. The whole Green Moun- 
tain range, and the loftier Presidential line of White Mountain summits, 
show this direction of marking. Scarcely any other course is known in 
Coos county, and it is common all through the Lake and Coast districts, 
including Essex county, Mass., and all the mountains of the Monadnock 
type. On comparing these courses over so much of New England with 
the customary south-east course of the valley of the St. Lawrence, one 
perceives a very striking contrast, and has the difficult problem of the 
course of the south-east current set sharply before him. How could the 
ice-sheet climb the highest New England mountains from the low St. 
Lawrence valley, and then press onward to the sea? I will not attempt 
the answer at present, but offer, in the first place, our reasons in full for 
believing the ice current passed over the summit of Mt. Washington. 


EvipENcEs oF GuacraL ACTION uPpoN Mr. WASHINGTON. 


As this is the highest summit in the whole glaciated area of North 
America, geologists have been greatly interested in examining its sides, 
to note how far the ice-marks could be found. The most important visit 
in that regard was that of my father in 1841, and the observations then 
made universally accepted. Most other geologists have visited the moun- 
tain, but have had no occasion to publish anything about the phenomena. 
My father, in 1841, became greatly interested in drift phenomena, and 
visited the White Mountains for the purpose of determining the limits of 
the ice-action. He came from Conway through the Notch, passing up 
the Crawford bridle-path. “Along the whole course of the valley,” he 
says, “I noticed rather fewer of the phenomena of drift than in most of 
the mountain valleys of New England.” After describing the route of 
the path, he says,— 


All the peaks which I ascended are made up of broken fragments of this slate, which 
have been entirely removed from their original position by frost, and form sometimes 
a coating of loose angular blocks several feet thick. This is particularly the case upon 
the summit of Mt. Washington, and downward about 1,000 feet [see frontispiece, vol. 
i]; but in all the valleys between these peaks more or less of the rocks appear in place, 


204 SURFACE GEOLOGY. 


and here I discovered many examples of embossed rocks. They are, as we might 
expect, much less distinct than in many other places less exposed to decomposing 
agencies, and I should probably have passed by them without recognition, had I not 
previously examined many other more distinct examples. So far as Mt. Clinton has 
been uncovered, it seems one huge boss more or less rounded. As we begin to ascend 
Mt. Pleasant, the embossed rocks are quite distinct; and here, too, are boulders most 
evidently transported. Here, too, I discovered strie# running N. 30° W., S. 30° E., 
corresponding essentially with the general course of stria on the mountains of New 
Hampshire and Massachusetts. * * Near the south foot of Mt. Franklin is another 
example of the embossed rocks with boulders. * * Finally, at the south foot of Mt. 
Washington, near a small pond called Lake of the Clouds, is a third example of the 
Roches moutonnes. Itis less distinct than at the other localities, as the rock here is 
more broken up by frost; still itis impossible for a practised eye not to recognize 
them. And it ought to be stated that here it is the north-west exposure of the rocks 
that has been most powerfully acted upon, proving conclusively that the force was ex- 
erted from that direction. * * Can there be any reasonable doubt that the rocks on 
the summits of all these peaks were once abraded by the same agency, and that, were 
they in place, they would still exhibit traces of it? 

Conclusions. In the first place, the same glacio-aqueous agency that has operated in 
a south-easterly direction over the northern parts of the continent, at the lowest and at 
intermediary levels, has acted in the same manner and in the same direction upon the 
summits of the White Mountains. * * Hence, thirdly, we have no reason to sup- 
pose that the White Mountains have ever been a centre from which boulders have been 
dispersed ; and no evidence has been discovered on the sides of the mountain of the 


former existence of glaciers. * * * * * * 


But as no ice-marks were discovered on the highest summit, my father 
and others could not affirm what they seemed to have believed, that the 
glacier did move over the summit. Every geological text-book in the 
land has followed the leading of the facts just stated; and it has seemed 
an established dictum, that no ice marks could occur above about five 
thousand feet. 

In 1870 I traversed Mt. Washington, following the usual paths, and 
discovered small transported stones of a nature foreign to the moun- 
tain, at an altitude of 5,800 feet. The locality was at the then upper 
tank of the railway. Not much search was made, as it seemed prepos- 
terous to question the conclusions of my predecessors, though my note- 
book stated that the ledges above these pebbles exhibit the usual appear- 
ance of embossment produced by glacial agency, the force having come 
from a north-westerly direction, but no strize were seen upon them. In 


GLACIAL DRIFT. 205 


the years following scarcely any thought was bestowed upon the subject ; 
and it was almost by accident that, in 1875, I found decisive evidence to 
prove the passage of the glacial sheet over the summit of Mt. Washing- 
ton. Very shortly afterwards the story of the discovery was communi- 
cated to the public, as follows, at the Detroit meeting of the American 
Association for the Advancement of Science: 


The first suggestion of this novel proposition came to me the last day of July, 1875, 
from an examination of the somewhat rounded stones of small size lying along the car- 
riage-road upon the north-east side of the mountain, about two hundred and fifty feet 
below the summit. I stumbled upon two boulders of granitic gneiss foreign to the 
mountain, one nearly ten and the other six inches long. This raised the altitude at 
which transported materials existed to above 6,000 feet. Observation showed that 
these boulders came invariably from the earth underlying the conspicuous angular dé- 
bris common all over the peak above the line of trees. In repairing the road, the 
workmen usually dug beneath the surface blocks before obtaining a material suitable 
for their purposes, and there always seemed to be a plenty of it. This earth proves to 
be the ordinary ground moraine of modern glacialists, full of the worn angular and 
roundish stones, which have been fashioned peculiarly by being shoved along. Large 
boulders are not common in it, though abundant elsewhere. These stones are usually 
of the same mica schist and gneissic rocks that compose the adjacent ledges; and this 
kind of ledge extends to Israel river, five or six miles distant from the top of Mt. Wash- 
ington in a north-westerly direction. Were these deposits situated in the lowlands, 
they would be pronounced at first sight by any one to be the common drift heaps of 
the neighborhood. I did not discover satisfactory evidences of striation upon the few 
stones picked up near the two boulders of granite just mentioned, but they possess the 
characteristic shapes of those that are covered with scratches elsewhere. Some are 
pointed at both ends, being either flattened or round along the middle. Others are 
squarish or trapezoidal, with rounded corners. Many resemble perfectly the shapes 
figured by Geikie in his recent work on Zhe Great Jce Age; and, in fact, they are 
of the constantly occurring forms familiar to all glacialists. The rock is quite soft, and 
that fact may explain the absence of striation. 

The question naturally arose, as I lifted up these stones, Are these the shapes result- 
ing from the cleavage of ledges by frost? No, it could not be; some agency of trans- 
portation other than the falling down a slope has worn off the edges, smoothed their 
surfaces, and mixed them with earth. The glacial ice must have transported them, 
though they cannot have travelled more than five or six miles, or the limit of the extent 
of this kind of rock. If this were so, then the whole of Mt. Washington was covered 
by the glacier ice. Thus I reasoned with myself, and began to look further. Remem- 
bering that these glaciated stones came from below the surface, I sought for localities 
where the lower earth had been excavated. The first case examined was the founda- 

VOL, Ill. 27 


206 SURFACE GEOLOGY. 


tion of the Mt. Washington hotel. In laying the foundation of this edifice,—nearly 
two hundred feet long,—the angular débris was first taken up and placed in the cellar 
walls. When this had been used up, the workmen reached the same moraine mass 
which occurs below, along the carriage-road. Some of the earth was sandy, and went 
into the composition of the mortar used on the walls. There was scarcely any ledge 
requiring removal. I examined such of the stones as remained in the cellar as well as 
possible with a dim lantern, and found everything in agreement with the character of 
the materials seen two hundred and fifty feet lower along the carriage-road. The stones 
assumed the ordinary glaciated shapes, but I did not discover any material foreign to 
the mountain. One of the quartz fragments seemed to show traces of smoothing or 
incipient striation. . 

Next, I examined the excavations made for the road between the house and stables, 
and obtained several small boulders, four or five inches long, corresponding in mineral 
structure with the ledges in Randolph and Jefferson, twelve or fifteen miles away. The 
general color of the rock is so like that of the mountain that one would not perceive 
the difference between them without close inspection. The mica is arranged differently 
in it; the white parts are more abundant, though in fine grains, and the rock is evi- 
dently the same with the upper member of what I call the ‘‘Bethlehem gneiss” in the 
New Hampshire reports. The highest point at which stones of foreign origin were ob- 
tainable may be twenty or twenty-five feet below the very pinnacle of the mountain. 
Hence it is fair to conclude that every part has been covered by the glacial ice. , The 
glaciated stones, composed of the same material with that of the mountain, are com- 
mon all along this road to the stables; and elsewhere in excavations over the summit. 

Being unexpectedly called away, I had not time to search carefully for striae upon 
the ledges. Just beyond the signal station dwelling I found a flat ledge sloping a little 
north-westerly but precipitous on the south-east. Atmospheric agencies have marred 
the surface so much that no striz are visible, even if they ever existed. I had pro- 
posed to scrutinize every harder projection of quartz with a lens, as this course some- 
times reveals striation where other inspection is unavailing. Were this ledge situated 
near the Lake of the Clouds, where embossment is common, I should point it out 
unhesitatingly as an example of ice-sculpture, though much degraded by weathering. 
The shape agrees with that of thousands of glaciated ledges in other parts of the state. 
Other ledges on the mountain further north resemble this one. Inasmuch as the trans- 
portation of materials is clearly proved by the presence of the Jefferson rock upon the 
summit a few rods away, it will not be unreasonable to believe that this apparent em- 
bossment is real. The altitude of the ledge is the same with that of the site of the 
travelled stones. 

The disposition of the large blocks upon the summit is noteworthy. Several acres 
of surface are covered by them far away from visible ledges. As you approach a ledge, 
it is easy to see what fragments have been separated by frost action, as the projections 
match the indentations; and a very few feet of distance represent the extreme amount 
of removal, save on a steep slope. Since the surface covered by the large angular 


GLACIAL DRIFT. 207 


blocks is quite extensive and comparatively level, it is fair to conclude that the trans- 
portation has been affected by the glacier and not by frost. The latter agency, how- 
ever, has very industriously operated upon both ledges and boulders in post-glacial 
times, so that the shattered ledges, their fragments, and the fractured boulders form a 
continuous field of angular débris over the whole upper cone of the mountain. 

From these facts, the following conclusions seem legitimate: 

1. The glacial ice completely covered and passed over the summit of Mt. Washing- 
ton in a south-easterly direction. 

2. It brought along a large amount of moraine rubbish and glaciated stones, which 
were disposed in various hollows and convenient locations about the mountain, in the 
same way that the ground moraine is distributed in the lowlands. 

3. Subsequently an immense number of large blocks of stone, taken from the north- 
ern slope of the mountains, were transported to the summit (as well as beyond), and 
left overlying the finer earth débris of a previous transport. 

4. Frost and gravity have been acting upon the boulders thus transported and the 
ledges, so that every large block has been split up into smaller ones; and this angular 
débris entirely conceals from view the previously formed moraine, and the summit is 
apparently destitute of soil. 


After the announcement of this discovery, it was objected by some 
that these transported foreign stones might have been brought by team- 
sters or by the railroad. It was said to be a common custom for the 
men to place canvas over articles in their vehicles for protection, and to 
fasten down the cloth by stones. On reaching the summit, the stones 
would be thrown away, and perhaps the glaciated bits might be some of 
the fragments thus transported. The boulders I found were not over 
two pounds in weight. These would hardly be sufficient to hold canvas 
down in a wagon in the teeth of the formidable winds often blowing at 
the summit. Still, I thought it best to search further in localities not 
reached by débris. About fifty feet below the summit, midway between 
the railway and carriage-road, I soon found a rounded block of light gray 
Bethlehem gneiss weighing ninety-one pounds, evidently the rock that is 
common about Jefferson, but very different from the material composing 
the mountain. It lay beneath other fragments of stone, partly embedded 
in earth, and showed patches of the common yellow lichen of the summit 
growing upon it, older than the date of the building of either road. TI 
therefore concluded that no human agency ever brought this heavy stone 
and planted lichens upon it; nor is it probable the ones first discovered 
reached the summit except as borne by ice. Hence the proof of the 


208 SURFACE GEOLOGY. 


presence of glaciated foreign transported boulders upon the summit of 
Mt. Washington is indisputable. These consist of two different mem- 
bers of the Bethlehem group, together with a trap rock of unknown 
origin. The larger boulder is preserved in the state museum at Hanover. 

Further examination of the smoothed ledge west of the signal office 
confirms the impression of ice-action mentioned above. Faint markings 
indicate the course of S. 43° E., while the smoothing is very obvious to 
the touch, and is best seen where some of the ledge had been recently 
exposed, and especially upon a finer-grained stratum than usually oc- 
curs. The weather roughens every exposed surface in a very short time, 
so that this smoothness cannot be expected to continue a great while. 
This example was shown to Mr. E. Lewis, Jr., of Brooklyn, N. Y., a geolo- 
gist familiar with glacial phenomena, who agreed with me as to its nature 
and origin. The course of the strize and dispersion of the boulders both 
indicate the movement of the ice to have been from the north-west to 
the south-east, a direction in unison with corresponding phenomena 
upon the neighboring summits. It is therefore clear that the ice moved 
south-easterly from the St. Lawrence valley towards and over the high- 
est ranges and peaks of New England (6,291 feet), in the direction of the 
Atlantic ocean. Our discoveries may increase the difficulty of explaining 
glacial phenomena in New Hampshire; but it is better to meet the truth, 
though formidable, than to adopt errors. All speculations, claiming that 
Mt. Washington rose above the ice, or constituted the central peak from 
which local glaciers radiated in the height of the glacial period, are false. 
It will be shown soon, however, that local glaciers occupied the flanks of 
the White Mountains during the decline of the ice period. This does 
not interfere with the fact of the earlier mightier movements. 


Directions WEsT oF SOUTH. 


A few examples of a current west of south have been observed. The 
first of importance occurs upon the east side of Mt. Washington, pass- 
ing from Gorham up the Peabody valley to the Glen house, thence to 
the height of land and down the Ellis valley past Jackson. The course 
is S. 15° W. near the Glen house; S. 3° W., half a mile south; and per- 
haps a little east of south into Jackson. The valley must have been 
filled certainly as high as the Half-way house on the carriage-road, where 


GLACIAL DRIFT. 209 


the course is S. 8° W. Perhaps the most natural way to explain this 
case is, to say that ice from the north entered the mouth of the valley 
at Gorham, and, being powerfully urged onwards, followed up the Pea- 
body river, because that lay in the direction of least resistance. Whether 
this action was coeval with the motion on Mt. Washington, is doubtful ; 
most likely the intensity of that force had somewhat abated before this 
culminated. The valley is on the lee side of the mountains, and might 
possibly have been moving at the same time with that on the summits 
without inteference. Dr. Packard has cited this valley movement as an 
illustration of a local glacier passing northerly down the Peabody river 
to join the Androscoggin.* In this he is followed by Vose.t The latter 
thus states the case: 


The Peabody river rises upon the eastern slopes of Madison, Adams, Jefferson, Clay, 
and Washington, and upon the western slopes of the opposite range of the Carter 
mountains,—the Imp and Mt. Moriah, and flows about N. N. E. to Gorham, where it 
joins the Androscoggin. The surface geology of this valley is exceedingly interesting. 
It has been carefully studied by Dr. Packard, and, from the arrangement of its 
terraces and the other forms of the unconsolidated material, he concluded that a large 
glacier once occupied this valley, extending as far down as toGorham. His conclusion 
is somewhat confirmed by the following facts: About 150 yards north of the Glen 
house, just south of a large boulder upon the west side of the road, the surface has 
been cut open, and has exposed a portion of a ledge, perhaps a dozen feet in length 
and a yard wide, on which, at right angles to the contorted lamination of the rock, 
faint lines, or, rather, furrows, are seen, running N. 35° E. or S. 35° W. This ledge 
was covered several feet deep by the material of the terrace in front of the Glen house. 
Just across the valley from the hotel, where the carriage-road commences to ascend, 
the upper part of the large exposure on the right hand is well polished and furrowed in 
a south-west direction. Half a mile further up the road, furrows upon the right side, 
close to the road, are seen running S. 40° W. or N. 40° E.; and, again, a short dis- 
tance above the path leading to Tuckerman’s Ravine, upon a surface somewhat inclined 
towards the road, may be seen lines running S. 30° W. or N. 30° E. Many more 
traces would doubtless be found in this neighborhood, if sought for with care, as the 
few recorded were noted without stepping out of the common road. 


These and other examples given in the table have been carefully ex- 
amined; but I am satisfied the force proceeded up instead of down the 
valley. If the facts about stoss and lee sides of ledges declare truth, 


* American Naturalist, vol. i, p. 267. 
F I'd, vol. ii, p. 287. 


210 SURFACE GEOLOGY. 


there can be little doubt as to the south-west direction. Some of the 
examples given require scrutiny to decide which is the stoss and which 
the lee side, but all present the same appearances. Perhaps the most 
satisfactory cases are recently exposed by a clearing midway between 
the Glen house and the saw-mill, not seen by either Packard or Vose, 
The rounding on the north sides of the domes here is very conspicuous, 
while the south sides are rough and uneven, though not so much so as 
in the most perfect examples of stoss and lee action. At the lower end 
of the carriage-road the smoothing occupies a broad face of rock 200 feet 
long and 40 wide, with the north-east end the most worn. Two miles 
up this road the markings are on a vertical wall exhibiting a well defined 
example of the north-east force. A short distance south from the Glen 
house, where a tributary enters from the south-east, the greatest amount 
of wearing appears at the angle of the fork, and not upon its sides. 
All these cases show clearly that the principal force, or that making the 
striz and producing the embossment, proceeded west of south, and not 
northerly. There may have been a later current down the valley in the 
decline of the period, but this did not have strength enough to score 
the ledges. This later current explains the origin of the immense thick- 
ness of stratified deposits near the mouth of the Peabody river, called 
moraines by Packard and Vose. They are relics of the ancient flood 
plain, produced by the glacial river after the ice had been melted, cer- 
tainly as far up as the Glen house. These terraces are very conspicuous 
as far south as the mouth of Miss Barnes’s brook, and show differences 
in coloration like those between the upper and lower till. Mr. Upham 
agrees with me in this view (see p. 141), without any conference or sug- 
gestion whatever from me. 

The next examples of the movement west of south occur on the west 
side of the Presidential range, and seem to connect with the Connecticut 
Valley movement. It has not been observed in Carroll, probably be- 
cause of the scarcity of ledges. Observations are also wanting for 
Whitefield. Bethlehem abounds with them. The north-west slope of 
the Mt. Agassiz eminence has been powerfully struck and smoothed by 
it. This current passed over the summit of Mt. Agassiz, and followed 
some portions of its southern slope. From here southerly the current 
is merged with that of the Connecticut Valley movement. That seems 


GLACIAL DRIFT. 211 


to commence with the Passumpsic. The great westerly bend of this 
valley below Dalton, and the sudden fall of the land, may have prevented 
the ice of the upper Cods flats from descending to Barnet. Certain strize 
in West Littleton, near Milliken’s saw-mill, cross the Connecticut, and 
ascend Gardner mountain in preference to following around the lowland. 
Our numerous observations in Littleton, Lyman, and Monroe show that 
the prevailing course was a little west of south, conforming both to the 
longer axis of the Gardner range and the Connecticut valley. The whole 
area of this westerly course may be readily referred to the Connecticut 
Valley movement, of which more will be said beyond. 

Another area, showing a course west of south, is in the Lake District. 
We have on the south slope of Pequawket, S. 6° W. (misprinted in the 
table); Madison, S. 7° and 12° W., besides S. and S. 2° E.; Brownfield, 
Me., S. 18° W.; Eaton, S. 3° E. This area is essentially a valley sloping 
southerly; but there are no indications of this direction in its continua- 
tion in Ossipee or Wakefield, nor in the broad opening to the south- 
west between the Chocorua and Ossipee mountains. The striz point 
south-east in both these localities. Hence the reason for this course 
in the Lake District is not obvious. Probably extensive explorations in 
Maine will be required for the solution of this problem. 

Those nearer the coast might be referred possibly to iceberg agency, 
or to some connection with the ocean. They are at Cape Elizabeth, 
close to salt water, S. 8° W.; at Limington, Me., S. 33° W., numerous 
and well marked for half a mile’s distance, seen in crossing a hill; at 
Danville Junction, Me., a little west of south; and at Bow lake in Straf- 
ford, S. 31° and 58° W. The usual direction in this neighborhood is 
fairly at right angles with these. Is it possible that these are scanty 
relics of a once abundant south-west glaciation? Some of the lenticular 
hills, about to be described, are arranged in a line suggestive of a con- 
nection with a south-westerly current, much more extensive than is indi-. 
cated by the striz. The course of S. 59° W. in Sutton cannot easily be 
classed with either of the foregoing. 

We cannot properly appreciate the importance of this movement 
without reference to other observed examples obtained outside of New 
Hampshire. In Maine they are S. 8° W. at Saco, and about the same at 
Rockport. In Vermont they are S. 50° W. at Halfax centre; S. 28° W. 


212 SURFACE GEOLOGY. 


at Marlborough. In Massachusetts they are S. 20° W. on the summit 
of Mt. Pocumtuc, 1,888 feet above the sea; S. 50° W. at Granville, 1,240 
feet. In Connecticut, according to Prof. Dana, there are stria proceed- 
ing S. 30° W. oh Mt. Carmel, and S. 33° W. half a mile west of Alling- 
town on the Milford turnpike, a few miles west of New Haven. 


Soutu-East DirEcTION. 


The south-east course is well-nigh universal. All over Cods county 
and about the White Mountains there is scarcely any variation from it 
upon the high ground. It is the most common in the lower part of Car- 
roll, Strafford, east part of Merrimack, east part of Rockingham, and on 
the isolated mountains of the Monadnock type everywhere. In Belknap 
and the west part of Rockingham the course averages a little less east- 
erly than south-east. The Winnipiseogee Lake neighborhood is much 
the same. In all the regions showing a west of south course are many 
cases of this south-east grooving. About Madison we have noted S. 22° 
E. The Strafford hills indicate S. 35°-78° E. In the Connecticut val- 
ley numerous examples are given. We find in Lancaster, S. 23° E.; at 
Haverhill, S. 21° E at Newbury, Vt. S. 23° E.; at East Lisbon, S. 28° 
E.; in Bethlehem, S. 28° E.; in Piermont, S. 42° E.; in Lyme, as high as 
S. 31° E.; in Hanover, S. 38° and 51° E.; in Lebanon, S. 51° E,; in En- 
field, S. 16°-61" E., but most commonly about S. 22° E. A full descrip- 
tion has been given already of the remarkable eastings in Claremont. 
At Unity the course S. 51° E. occurs, and S. 61° E. at Hinsdale. Along 
the Connecticut-Merrimack water-shed the direction is commonly be- 
tween S. 20° and 40° E. These south-east courses in this valley must 
not be confounded with those conforming to the direction of its contour, 
about to be mentioned. 

The universality of a south-east course among the strize shows that 
this was the most common direction taken by the ice in its southerly 
movement. All other directions are exceptional, and probably produced 
subsequently by an action differently directed. 


VALLEY MoveEMENTS. 


To this class I refer all those examples of striation where the ice 
seems to have followed the topographical contour of the country, includ- 


GLACIAL DRIFT. 213 


ing all the local glaciers. In most glaciated countries it has been found 
practicable to refer all the ice-action to this class of movement; but in 
New Hampshire the most characteristic phenomena have resulted from 
a motion made in total disregard of all topographical obstacles or allure- 
ments. On the supposition that ice moves up hill only when forced by a 
flow starting from an eminence higher than what is being surmounted, 
we must believe that, to the north of the St. Lawrence valley, the land 
was elevated several thousand feet higher than at present. This is Prof. 
Dana's view. It must be adopted, unless we can show that reasons 
exist why the ice can move up hills higher than the source of the flow. 

The most important valley movements in New Hampshire are those 
in the Connecticut, Merrimack, Blackwater, Baker’s river and Winni- 
piseogee lake, the Androscoggin, Saco, and others. I will describe each 
in turn. 

Connecticut Glacier. None are better marked than this. It starts with 
the Passumpsic and the Lower Ammonoosuc valleys, and, below Haver- 
hill, occupies commonly the width of two townships, one on each side of 
the river, into Massachusetts. It continues across Massachusetts, with 
a course a little west of south, as has been described in my father’s pub- 
lications. On both sides the course is east of south. It follows, there- 
fore, that this movement must have been entirely independent of all 
others. As it conforms to the valley, while here and there a few rem- 
nants of the south-east course remain as relics, its existence was proba- 
bly subsequent to-the other, and in the decline of the period. By observ- 
ing the present heights of the striated ledges, we can determine the min- 
imum thickness of this glacier. It covered Mt. Agassiz in Bethlehem, 
the higher parts of Lisbon and Landaff, the Gardner mountains, or over 
2,000 feet of altitude. Lower down the valley it attained the height 
of 1,100 feet at the Haverhill soapstone ledge; 1,400 feet near Tarlton 
pond in Piermont and Warren; 1,500 feet upon Sunday mountain in Or- 
ford; 1,600 feet in the south-east part of Hanover; and it may have 
reached the summit of Mt. Ascutney, or over 3,000 feet. South of this 
mountain, none of the recorded observations exceed 1,000 feet,—most 
fall below it. On Bear hill, Hinsdale, they stand at 700 feet. In Mas- 
sachusetts we found one example, at New Salem, on the east rim of the 


valley, certainly as much as 1,200 feet high. Similar marks have been 
VOL. III. 28 


214 SURFACE GEOLOGY. 


found at the same height over the Holyoke range, or upon Mt. Tom. 
Allowing for the elevation of the river bed, this glacier must have ex- 
ceeded 1500 feet in thickness in the Ammonoosuc valley, and probably 
2800 feet at Windsor. From Prof. Dana’s paper,” it is obvious that the 
ice continued a little west of south to New Haven, Conn., thus following 
the depression of the valley to Long Island sound. The breadth of the 
area showing strize conforming to the river’s course is greater in Massa- 
chusetts and Connecticut than in New Hampshire and Vermont, as might 
be expected where the valley itself is broader. So far as can be conject- 
ured, the heights are less in the more southern states; and it is bounded 
by the east of south course on both sides as sharply as further north. 

It would be repeating observations uselessly to print again the numer- 
ous statements about the course of the strize along this valley given in 
our table. That may be consulted to understand how fully the river 
towns abound with groovings following the general course of the valley. 

Prof. Dana argues that the Connecticut valley ice moved towards the 
sea at the same time that the great ice movement was in progress south- 
easterly upon both sides, and explains it as the necessary result of a nat- 
ural law. “It moves just as thick pitch poured over a sloping surface, 
in which there are a few large groovings, would move, the mass follow- 
ing the general surface, and the portions in the grooves nearly or quite 
the course of the grooves. The thickness of the ice that followed the 
course of the valley was at least 2,000 feet.’ Three considerations are 
presented in favor of this view :—first, in Massachusetts and Connecticut 
only the course with the valley has been observed; second, if the glacier 
were local, 2,000 or 3,000 feet thick, the southerly scratches ought to be 
found further west than they now are; third, there is more easting in 
the course north of Massachusetts, as if produced by some part of the 
general movement. I think it much better to believe the Connecticut 
Valley movement was confined exactly to the limits where its evidences 
are found, and to say that the south-east courses found here and there 
within it are the relics of an earlier and grander glaciation. In fact, 
when different parts of the same ledge, as in Hinsdale, show the courses 
S, 10° E. and S. 60° E., no amount of argument can convince one that the 
ice moved in both these directions at the same time. It is impossible. 


* Am. Four. Science, iii, vol. 2, p. 233. 


GLACIAL DRIFT. 215 


The phenomena agree best with the theory that the south-east course 
originally covered both the valley and the adjacent borders for scores of 
miles, but that, after the ice ceased to be furnished abundantly from the 
St. Lawrence, the residue followed its natural way down the several river 
depressions to the sea, and, being of considerable thickness, was able to 
leave abundant evidences of its passage. 

Prof, J. D. Dana was the first to insist upon the existence of a Con- 
necticut glacier separate from the general mass of drift. My father was 
the first of American geologists to point out the fact in any publication 
of the existence of local glaciers radiating from high ridges.* He was 
led to this conclusion from a comparison of the ancient glacial drift in 
Wales and Switzerland with the drift generally, and with the local exam- 
ples seen by him in western Massachusetts and Vermont. As the 
common phenomena of the drift seemed to him best explicable upon the 
iceberg theory, his ready recognition of the real glacial markings in the 
Westfield and Deerfield River valleys shows how ready he was to accept 
truth, even against his judgment of the proper interpretation of the 
phenomena of nature. His suggestion of a movement down the Con- 
necticut valley is not to be regarded as a claim that he understood the 
whole depression to be scored like the few examples he had seen.t The 
fact established clearly by him was, that the Hoosac and Green Moun- 
tains supported the mer de glace in the last part of the ice period, from 
which local glaciers flowed down, both towards the Connecticut on the 
east, and to the Champlain valley on the west. We can now extend this 
deduction eastwardly, and say that there was a Connecticut Valley gla- 
cier in the latter part of the ice period, with branches both from the 
west and the east. 

The branch glaciers on the west that have been described are these: 
Upon Westfield river, with its tributaries, especially Little river ; Deer- 
field river, both in Massachusetts and Vermont; West river, joining the 


* Report Geology of Massachusetts, 1853. Smithsonian Contributions, vol. ix. 


+ The following is the passage referred to (Smithsonian Contributions, vol. ix, p. 136): On examination, I did 
find, on the west side of the Connecticut valley, that what I called drift striz, instead of running north and aide 
as they usually do, turn southerly south of South Hampton as much, in some places, as S. 65° W. I Saspected 
at first, either that these markings were produced by the [Westfield] glacier, after it reached the Connecticut val- 
ley, or that the supposed glacier scratches were the result of drift agency operating up hill. But when I found 
that the stoss of the glacier striz was the west side, and that of the drift strize was the north-east, both these su 
positions were shown to be untenable ; aud I accounted for the south-west direction of the drift striz by he 


expansion to the right of the Connecticut valley south of South Hampton. I think this the ri i 
i e right i 
of the facts, but I could wish to give them further examination. i i 


216 SURFACE GEOLOGY. 


Connecticut just above Brattleborough ; Saxton’s river; Black river in 
Ludlow and Cavendish ; Otta Quechee river; White river. Those far- 
ther north have not been particularly explored. On the east side, the 
branches of this glacier are not well marked. This may be explained 
partly from lack of attention directed to their discovery, but chiefly be- 
cause the east side of the basin is very narrow. There is not sufficient 
room for the glaciers to form, and to make much sign of their existence. 
In Massachusetts, Miller’s and the tributaries of the Chicopee river might 
furnish some indications of the former presence of the ice. In New 
Hampshire, the Ashuelot is the first valley where we could search for 
these relics. They may be expected in Winchester, where the river 
changes its course to pass between hills, and in the towns of Surry and 
Gilsum. It will be singular if these localities do not afford strize or other 
indications of the tributary ice-sheets. We have no observations for Cold 
river; and all that has been noted in the Sugar River valley indicates 
the passage of the ice up instead of down the stream. The marks of 
the older south-east current were so pronounced that any action of a 
force in the opposite direction might be unnoticed. The Mascomy val- 
ley is rather short; and ledges between Enfield and Hartford, Vt., are 
rare. There is a moraine-like accumulation of till about a quarter of a 
mile below the outlet of the lake, whose origin may be explained either 
by supposing it to be the frontal rubbish of a local glacier, or the filling 
up of the valley by the south-east current from Hayes hill. The exist- 
ence of the projecting hill is very marked ; and it is spoken of by the resi- 
dents of East Lebanon as a former barrier to the progress of the water, so 
that the lake must once have had a much greater extension, leaving its 
shore marks forty or fifty feet above the present level of the water in 
beaches of sand. Excavations in this barrier show both the lower and 
upper till with great distinctness. Next come Mink brook, Hanover; 
Great brook, Lyme; Jacob’s brook, Orford; Bean’s and Eastman’s brooks, 
Piermont,—none of which afford marked glacial features, that is, we have 
not noted any. On the north branch of Jacob’s brook, between S. H. 
Sargent’s and the water, are many large blocks of Bethlehem gneiss, the 
rock which is in place a mile higher up, and not at the place of crossing. 
I did not follow down the stream to search further for these boulders. 
But the evidence is clear of the transportation of rocks down the stream 


GLACIAL DRIFT. 217 


in a westerly direction; and this may indicate what sort of phenomena 
should be looked for, in the other westerly descending valleys mentioned, 
to satisfy us of the existence of tributary glaciers. No pains have been 
taken to observe this class of facts. Oliverian brook in Haverhill may be 
expected to show some signs of a local glacier descending the west flank 
of Moosilauke. On page 30, considerations are presented to show that 
unusually abundant gravel and sand deposits in Haverhill must have 
been derived from such a source as this local glacier would be. We have 
also a barrier-like ridge of till lying across the Oliverian valley suggestive 
of a former terminal moraine. There are many boulders of Bethlehem 
and porphyritic gneiss in the Oliverian valley, seemingly of eastern origin. 
If not from the Moosilauke pile, they must have been brought down by 
the main Connecticut Valley ice. The numerous marks between Haver- 
hill and Carroll may be regarded as made by one branch of the Con- 
necticut glacier. These are very abundant, and satisfactorily illustrate 
the local movement. Those down the Passumpsic valley are less com- 
mon and convincing. 

Above the Ammonoosuc district the Connecticut Valley movement 
seems to have been interrupted in consequence of the presence of the 
Gardner Mountain barrier. The markings in this part of the valley do 
not conform to the topography, and must therefore be regarded as made 
by the older movement. The map (PI. II) illustrates the nature of the 
ground over this space. Above Lancaster there are well marked signs 
of a local glacier, probably the last movement in the region, separate 
from and later than that just described. Its existence is manifested by 
moraines and not by striae, and may be classed with the Bethlehem gla- 
cier, to be described presently in the words of the late Prof. Agassiz. 

Midway between Stratford Hollow and North Stratford is a pile of 
granite boulders so conspicuous as to arrest the attention of the most 
careless, They occupy several acres of ground, and seem to form a ter- 
minal moraine. It is represented in Fig. 53. The exact location is indi- 
cated by the word Moraine on Pl. I; and a section crossing the valley is 
shown in Fig. 2. Mr. Clough’s stereoscopic view of the same is entitled 
“New Hampshire Cow Pasture.” The name indicates the use to which 
the field is put, while the abundance of boulders seems to have discouraged 
the owner from attempting to make a stone wall of the material. A 


218 SURFACE GEOLOGY. 


dozen walls would so slightly exhaust the supply that none of the boul- 
ders would be missed. The largest boulder represented weighs about 
1,300 tons. On looking across the valley, similar boulders, but less abun- 
dant, can be seen on the Vermont side. I suppose they extend beneath 
the intervening meadow the whole distance, and therefore present us 


Fig. 53. MORAINE IN STRATFORD. 


with an admirable example of a terminal or frontal moraine. The mate- 
rial corresponds closely with the granite quarried a few miles up the 
Nulhegan river by the side of the Grand Trunk Railroad. The ice there 
seems to have descended the Nulhegan river before joining the frozen 
stream of the Upper Connecticut. Pl. I shows a projection of glacial 
drift into the valley, at Horseshoe pond, in Northumberland. This 
promontory is suggestive of other terminal moraines farther to the south. 
Ido not recall their nature, so as to say definitely whether the resem- 
blance is only accidental. It might be added, that the drift hills on 
Israel’s river approach each other closely, just above Lancaster village, 
in the manner of a frontal moraine. 

The Merrimack Movement. The limits of this particular ice mass 
would be naturally the east and west water-sheds, while the northern 


GLACIAL DRIFT. 219 


boundary does not extend beyond New Hampton on the main stream, 
passing instead to Newfound lake. The movement north of New Hamp- 
ton belongs to another area quite distinct. It is thus like the Connecti- 
cut glaciers, divided by a barrier above Monroe. As thus limited, the 
Merrimack glacier is with difficulty separated from the general south- 
easterly movement. The country is almost flat below Concord, so that 
there is little opportunity for a local glacier to exist for want of inclina- 
tion; and the western sloping valleys on the east side rarely show any 
marks pointing westerly. From Winnipiseogee lake to Franklin the de- 
scent is sufficiently great to induce motion, 225 feet in fifteen miles, but 
the ledges are covered, and no topographical feature suggests glaciation. 
Any special striation or embossment in the lower part of the Suncook 
and Soucook rivers would be concealed by the immense piles of alluvium 
of later origin. The upper Souhegan valleys are better adapted to show 
these evidences; and no situation could be better than that of the upper 
Contoocook for exhibiting traces of the glacial action distinct from that 
of the general drift. Warner river valley is much like the Souhegan. 
Three of the more northern tributaries of the Merrimack show good 
evidences of the valley movement,—Smith’s, Blackwater, and the Pemi- 
gewasset rivers. I will describe these first. 

Smith's River. This stream rises at Orange summit, follows the 
Northern railroad through Grafton and Danbury, and thence turns east- 
erly between Alexandria and Hill. The course of the valley usually 
corresponds with that of the general movement, but the phenomena of 
embossment are like those of local glaciers. In the Orange summit 
notch, the course is S. 36° E., a few more degrees easterly than is com- 
mon in Canaan and the north part of Orange. It is the same at the 
north end of Tewkesbury pond, but 5° less at the outlet. The rock 
for several miles about is admirably adapted to exhibit striation and 
embossment, and the phenomena at the outlet of the pond where 
the railroad passes can hardly be excelled for perfection in any part of 
the state. Any one familiar with glacial phenomena would instantly 
recognize them while passing in a train. At the mica quarries on the 
west side of Grafton valley, the course is about the same; also, at a 
school-house between the two Grafton stations. We should expect 
somewhat more easting at this point, as the course of the valley has 


220 SURFACE GEOLOGY. 


commenced to change. Two tributary valleys from the north, Mill and 
Whittier brooks, may show striation coursing more southerly ; but these, 
and all the rest of the Smith’s brook region, have not been specially 
examined with the object of noting the glaciation. The lower part of 
Smith’s river changes its course so much that if a mass of ice followed it, 
the variation in the direction of the striz would be very observable. 
Between Alexandria and Hill there has been considerable excavation 
since the ice period, so that the markings may be looked for away from 
the stream. We have good reason to expect to find evidence of local 
action all along Smith’s river, provided the ledges are not too much cov- 
ered up. 

Blackwater Valley, The map of local glaciers in Volume I represents 
the movement of the ice as continuous from Grafton and Danbury along 
the railroad, to connect with that in Andover along the Blackwater. I 
have separated them now, because it seems more natural for the ice to 
flow down Smith’s river to join the Pemigewasset, than to cross the Dan- 
bury water-shed, where the necessary rise is not far from a hundred feet. 
The course in the south part of Grafton, on the highlands, is such that 
the continental sheet points directly to Andover, or to the valley between 
Mts. Ragged and Kearsarge. It is not therefore certain that the ice go- 
ing down the Blackwater, whose marks remain, should be classed with 
the later movements. But it is certain that the course was modified by 
the valley, so that it belongs to the category of those motions whose 
course did not proceed in defiance of elevations and depressions of the 
surface. Several ledges at Potter Place and Andover show that the 
course was much more easterly than the very east directions upon Kear- 
sarge and Ragged [see page 200]. It has 20° more easting than on 
Kearsarge, and 40° more than upon Ragged. This course would natu- 
rally turn at Andover Centre, and proceed southerly through Salisbury, 
if it continues to conform to the valley, and not climb the hill at East 
Andover like the railroad. Such facts as are reported confirm this view. 
The East Andover ridge is occupied by drift, perhaps lenticular mo- 
raines; and the striae in West Franklin run S, 32° E., and therefore 
belong to a different movement. The top of a hill west of the Black- 
water, on the south town line, shows the course S. 38° E., and on its 
south slope are strize running down hill towards Salisbury. And in this 


GLACIAL DRIFT. 221 


last named town the courses are S, 12°, 15°, and 22° E,, the greatest 
easting being in the valley on Bean’s hill, near the south boundary line. 
The courses in Webster would not vary essentially from those in Salis- 
bury. 

The Pemigewasset below Ashland. Local glaciation probably reaches 
from the mouth of this stream at Franklin all the way to Newfound lake 
and up Cockermouth brook in Hebron and Groton. At the outlet of 
Webster lake the course is S. 32° E., which may represent the normal 
direction to the west of the Pemigewasset. North of Franklin village 
the direction is S. 27° E. This continues uniform for three miles; and 
the grooves and embossment are remarkably well developed near J. W. 
Simonds’s. At this point there is a conspicuous bend in the course of 
the valley; and the strize are observed to change their direction to con- 
form with the topography. At S. Pike’s, a mile beyond Simonds’s, the 
strie point S. 42° E. From here to Hill the valley broadens, and the 
ledges are covered by sand. At the east side of the river, in the north- 
east edge of Franklin, the course is S. 22° E. down the valley, and the 
accompanying embossments are admirable. This locality is opposite to 
the first named examples below the prominent bend in the river. 

On the Sanbornton side of the valley, between Hill and Bristol, there 
are ledges which have their stoss sides marked from the north, and they 
probably present other illustrations of the local action. Our table con- 
tains several observations of south-east strie down the valley of Cocker- 
mouth brook in Groton. The east side of the lake shows other striae, 
however, pointing up hill, and therefore having no connection with the 
local glacier. 

There are examples of a local sliding in New Hampton and Bridge- 
water. These are all connected with the Pemigewasset movement, and 
are mentioned in the tabular list. 

The Lower Merrimack. Several points may be made about the lower 
Merrimack movement. The general direction of the valley is S. 15° E., 
so that strize varying ten degrees from this on either side may be regarded 
as belonging to this special glacier. From Franklin to Massachusetts we 
have, in order, S. 15°-27° E.; Canterbury, 15°-40°; Boscawen, 17°-27°; 
Concord, 9°-11°-21°; Hooksett, 16°-26°; Manchester, 15°-26°; London- 


derry, 11°-21°; Souhegan village, 16°; Nashua, 11°; and in Hudson an 
VOL. WI. 29 


222 SURFACE GEOLOGY. 


interesting case of intersection, S. 3°x 21° x 36° E. On the east rim of 
the basin are higher figures. Belmont, 32’-42°; Gilmanton, 32°-52°; 
Loudon, 40°; Pittsfield, 42°; Deerfield, 40°; Northwood, 32°-37°; east 
part of Hooksett, 41°; ridge east of Manchester (quarries), 40°; Candia, 
21°-41°; Londonderry, 41°. It would seem as if these observations 
might be interpreted as indicating a difference between the direction of 
the forces down the valley and over the eastern rim. There are a few 
strongly marked south-east courses on the west rim, as through Wash- 
ington and Springfield, that are between 20° and 30°. Hence there is 
not that definiteness of demarcation between the rims and the valley 
courses that we found in the Connecticut. The three courses in Hud- 
son may perhaps be regarded as typical of as many different movements. 
The unusual direction of S. 72° E. in Deerfield, on the north side of Mt. 
Pawtuckaway, may have been due to the presence of the mountain mass. 

There is one example of striz sliding N. 40° W. on the east side of the 
valley. It is at the Amoskeag granite quarry in Manchester. Its exist- 
ence would not be known save for the removal of the earth for quarrying. 
Who knows how many more such cases may exist under these loose 
materials, sufficient to make sure the presence of the glacier in the 
Merrimack valley! 

In the Contoocook valley we find no evidence from striz to suggest 
the northward motion of the ice. Unusual accumulations of till at Hills- 
borough Bridge and in the west edge of Henniker are suggestive of ter- 
minal moraines pushed forward by such a movement. The striz in An- 
trim follow the course of the valley, but may have gone southerly. The 
North Branch valley, in the same town, is deep and narrow, and hence 
well fitted for the passage of a glacier. We find marks indicating that 
it was crossed by the main ice-sheet without regard to the depression. 

Our final conclusion, from all the facts, must be, that the Merrimack 
movement was largely a topographical modification of the course of the 
main ice-sheet. As occasional remnants of the genuine south-east cur- 
rent occur, it may be proper to say that the modification would naturally 
take place in the interval of time between the predominance of the south- 
east current and the local glaciers. And in the latter period the Mer- 
rimack ice became still more restricted, and feebly imitated the local 
action elsewhere. 


GLACIAL DRIFT. 223 


Baker's River and Winnipiseogee Movement. This is an interesting 
example of a movement seemingly both local and hardly separable from 
the action of the continental sheet. It starts with a south valley in Ben- 
ton, curves to the east with Baker’s River valley in Rumney, extends 
nearly due east over Squam lake and Sandwich, and then enters the val- 
ley of Winnipiseogee lake, merging into the normal south-east course 
after leaving this hydrographic basin. Allusion has been already made 
to the latter part of its course (p. 121 ef seg.). The movement down the 
upper Pemigewasset may be regarded as a branch of this. 

On the summit of Moosilauke the striz run S. 22° E., a course less 
easterly than is common over the high mountains of the state. This 
corresponds with the direction through Warren and Wentworth, save a 
few local tributaries in Warren mentioned in the table. The easting 
seems greater than the proper course of the valley; but a correspond- 
ence was noted between the direction of the strize and of the depression 
when the observation was recorded. The numerous observations in 
Rumney indicate a gradual bending of the scratches in complete agree- 
ment with the change in the course of the valley. On the south side, 
the south-east course does not reach the top of the rim, as the directions 
in Groton on the ridge between Baker's river and Cockermouth brook 
are S, 22° and 32° E. The glacier was certainly 500 feet thick, and prob- 
ably not much more at this point. In the west part of Plymouth and the 
south-east corner of Rumney are remarkably fine examples of striation 
and embossment of the ledges. I hardly think a finer place could be 
found for a photographic representation of these phenomena than of the 
east base of Hawks mountain in Rumney. A spur of the hill projects 
into the valley, which was struck powerfully by the ice as it descended, 
beautifully embossing the schists and scoring the domes with striz. One 
ledge has numerous large blocks of stone on top, some measuring as much 
as 20 feet long, 10 wide, and 8 high. Further west the mural striated 
surfaces are common, as between A. Kelley’s and J. Davis’s houses. 
On the north side of the valley two elevated ranges come close to the 
river,—Rattlesnake and Stinson mountains,—which are precipitous for 
two hundred feet. On these steep sides striz are often visible, though 
much of the rock containing them has fallen to the base of the hill. 
Wolf hill in Plymouth, a solitary bunch of granite in the midst of a low 


224 SURFACE GEOLOGY. 


country, has been passed over by this glacier as if it were of no con- 
sequence. 

The Pemigewasset valley turns to the south below Plymouth; but the 
strize continue on in the direction observed in Rumney, just as if the ice 
could not stop after it began to slide. The smallest easting in Holder- 
ness is S. 37° E,, on top of Mt. Prospect; the ridge of Squam mountain 
shows S. 62° E.; and there are others equally pronounced. Sandwich, 
however, shows the greatest amount of easting. At several places it 
travelled a little north of east, and the east course is frequent. The 
movement did not continue further east into Tamworth on the north 
side of the Ossipee mountains, since the marks there are quite southerly, 
though Chatham hill shows the course S. 42° E. The mass seems 
rather to have gone south-easterly to the lake through Moultonborough, 
and over Red hill, S. 62° E. On reaching Winnipiseogee lake the strize 
on the east side average a more easterly course than on the west side in 
the towns of Meredith, Gilford, and Alton. The occurrence of the Moose 
mountains directly in the path of the Winnipiseogee ice suggests whether 
the course was not changed on account of this obstacle in its way. It 
is a fact, that the course on the summit of these mountains is that of the 
longer axis of the lake, while there is a much greater easting to the north- 
east. The strize at Tuftonborough Corner run N. 68° E., as if crowded 
closely upon the flank of the Ossipee mountains. Nearly all the obser- 
vations in Tuftonborough, Wolfeborough, Brookfield, and Wakefield run 
between south-east and east. Mr. W. Upham explains this condition of 
things, by supposing the ice of the Ossipee basin melted earlier than that 
over Winnipiseogee, and hence the ice from the latter area moved towards 
the vacancy left on the east side. If most of the ice were forced to pass 
out between Ossipee and Moose mountains, a part of it might emerge 
through Alton. The striz there have a much less easting than on the 
other side of Moose. 

Thus it would appear that the topography of the country between 
Warren and Wakefield, along the valley of Baker’s river and Winnipi- 
seogee lake, determined somewhat the direction of the motion of the 
ice, whether it be regarded as a part of the continental sheet or a local 
movement. 

Upper Pemigewasset Movement. The observations of the striae in the 


GLACIAL DRIFT. 225 


upper Pemigewasset valley are grouped together in the table (p. 185). 
The valley runs southerly, and the striz mostly conform to it; at the 
very entrance, high up, we have the course S. 8° W., above the Eagle 
lakes on Mt. Lafayette. On the summit of Bald mountain, in the Fran- 
conia Notch, the course is S. 2° E., with a large boulder of Bethlehem 
gneiss on its summit. The same force went over Mt. Profile, leaving 
many boulders of the same kind. It appears from these circumstances 
that a large body of ice entered the valley from above, which must have 
been a portion of the larger and older sheet. This and the later local 
masses scored the vertical east side of Mt. Pemigewasset, with the course 
S. 12° E., working southerly. Other examples occur through Lincoln 
and Woodstock, following the valley. Were the forests cleared upon 
both sides of the stream, many other interesting examples would be 
found. At North Woodstock, the hills upon the west side display a 
magnificent embossment on a large scale, as worthy of photographic 
reproduction as those in Rumney. There seems to be more easting in 
lower Woodstock and Thornton than is needful to conform to the valley. 
This may be explained partly by the fact of local turns in the course, 
not obvious, except on the ground. On the rim of the valley to the 
south-east is the course S. 70° E., which may have influenced some- 
what the direction of the ice lower down, yet is sufficiently different to 
satisfy us that the marks in the valley were not produced by the same 
movement. Through Campton the scratches essentially follow the val- 
ley. A single case is reported from Mad river, high up, of a descent 
N. 32° W., or down one of its tributaries. This will be an example of 
the local movement, or possibly the result of a recent slide, described 
in Volume I. Below Campton, the Pemigewasset glacier joined the ice 
movement down Baker’s river, and went with that over to Lake Winni- 
piseogee. 

Androscoggin Movement. Should a glacier start from the Rangely 
lakes and follow down the whole Androscoggin river, the course would 
be to the south-west, then south, and then a turn to the east as far as 
Bethel, in Maine. We have evidence of a strong south-east current over 
Rangely lake, and in Upton on the east side of Umbagog lake,—a move- 
ment not of a local character. Down the Magalloway river, close by the 
College Grant, there was a well defined valley movement, S. 4° E,, 


226 SURFACE GEOLOGY. 


towards Umbagog lake. There is a pretty lateral moraine of granite 
blocks at the uppermost landing of the steamboat in Wentworth’s Loca- 
tion, resting upon Huronian schists. The rocks for several miles up the 
Magalloway are finely embossed. The numerous striz in Errol, S. 73° 
E., have no connection with the Androscoggin, and we have no further 
observations from this valley till we reach Gorham. The rocks here are 
much weathered, but have the aspect of ledges struck from above, with a 
few south-east striz. According to Vose, the striz upon the top of Mt. 
Hayes, directly opposite the opening of the Peabody valley, run S. 40° E,, 
or nearly at right angles to the direction up the river towards the Glen 
house. The Androscoggin valley, with its low, broad terraces, is very 
different from the high sand-banks near the mouth of its Peabody tribu- 
tary, suggesting the origin of the former under very unlike circumstances. 
The utter absence of all material transported down the Peabody at Gor- 
ham would indicate its removal by the powerful current of the Andros- 
coggin, for certainly such deposits could not fail to have been brought, 
and seemingly at a later date than the existence of the Androscoggin 
glacial river. These facts suggest either extensive freshets in post-gla- 
cial times, or the longer continuance of the Androscoggin glacier. The 
valley below Gorham village, for two miles or more, consists chiefly of 
rubbish from the sides, moved by the rains and frost, not in the terrace 
form. No particular signs of glacial action are seen before reaching the 
middle part of Shelburne, near the most northerly course of the river. 
Here, at the height of 150 feet above the railroad, upon a projecting 
ridge, are grooves pointing down the valley, S. 88°, N. 88° E. The east 
side is a rough cliff, never touched by ice action. At the extreme north 
point of the hill, the course is S. 63° E. On this lee side of the dome 
are many rough granite blocks, each from five to twenty feet in length. 
They have been transported only a short distance, and are properly a 
moraine caught behind the projecting ledge. These markings are those 
of a well defined local glacier. 

On reaching Clement’s brook are other fine embossments, with striz 
S. 73° E. The former have been described upon page 195. Local mo- 
raines appear upon the projecting side of these ledges. Similar emboss- 
ments occur on the north side of the river, opposite Clement’s brook. 
About a mile below Clement’s brook, opposite the first house with a con- 


GLACIAL DRIFT. 227 


spicuous tower, is a rough ledge, protecting moraine material. A simi- 
lar ledge further east has the west side rounded by ice. Near the state 
line is an outcrop of white gneiss, scored S. 58° E.,, and an enormous 
quantity of boulders, torn off the light colored ledges, follow for a short 
distance, These several examples of blocks torn from the ledges, but 
not carried far, illustrate the beginnings of glacial transportation. 

For about half a mile into Maine, in the town of Gilead, glacial marks 
are wanting. In the middle of the valley is a long rocky hill athwart its 

‘ course, behind which moraine material is gathered. At the north foot of 
Mt. Ephraim are strize S. 65° E., where the road and railroad draw close 
together. 

Grooving is well shown here. Above Mt. Ephraim the rounding looks 
as if it had been produced by a mass of ice coming down Ingalls river 
from the north. On the east side of Wild river the rocks have been well 
planed and embossed by the force down the Androscoggin. No explo- 
rations have been made up this tributary to ascertain whether ice-marks 
from the south-west may not exist there. At Gilead station, just north 
of the railroad and ten miles from Bethel, are furrows upon polished 
quartz running S. 40° E. A mile further east, where the road bends 
around a mountain spur, are strize S. 80° E. On the west side of Peaked 
hill, where the high land crowds closely upon the river, about 300 feet 
above the water, is a large, steeply inclined, magnificently polished sur- 
face, very plainly seen from the road below, a mile and a half distant, 
with faint lines and well defined furrows, S. 55°-60° E. The emboss- 
ment and planishment show even better from the north side of the river. 
On this north side, by the bridge at Gilead station and at the mouth of 
Peabody brook, are grooves following the course of the valley, and also 
large rough blocks removed only a short distance. At a church, the 
markings occur almost at the water's edge, with the direction S. 75° E. 
On the precipitous south side of Tumble-down Dick are many examples 
of strize on vertical surfaces; but the greatest force of the ice struck the 
ledges on the south side. At the base of the precipice, where floor sur- 
faces are exposed, are grooved areas 150 feet long, thoroughly planed down 
the whole distance. It would be difficult to find more beautiful examples 
of ice-sculpture in New Hampshire. The strie run S. 85° E. Near 
White brook are other strize and bosses, with rough south-east lee sides. 


228 SURFACE GEOLOGY. 


At the east line of Gilead, on the north side, the striz run S. 60° E. No 
further marks were seen on the north side of the river from this point to 
Bethel hill. Ledges are scarce, and covered by drift. 

The observations mentioned above, between Peaked hill and Gilead, 
on the south side of the river, are taken from Prof. Vose’s account of 
this interesting glacier.* I will quote his own words for the facts be- 
tween Peaked hill and Bethel. His course was up the valley from Bethel. 


Where glacial furrows are found upon the tops of the Bethel hills, they run nearly 
north and south. Proceeding up the valley towards Gorham upon the south bank, at 
a point about two and a half miles above Bethel, before we really enter the close valley, 
and perhaps one hundred feet above the river, a small exposure of rock is seen directly 
in the common road, being about six feet square, with a long, gently sloping polished 
surface towards the north, and a steep and rough face towards the south. The furrows 
upon the smooth northern surface run north and south; and the hills, upon the sum- 
mits of which the furrows run north and south, lie exactly north of this rock upon the 
opposite side of the river. This furrowing had evidently no connection with the An- 
droscoggin, as the grooves point almost directly across it. Continuing up the valley 
just above Pleasant river, five miles above Bethel, about a quarter of a mile south of 
the road and perhaps two hundred feet above the river, the rocks are well polished; 
and, from faint lines upon masses of quartz, the direction of the ice is seen to have 
been S. 50° E. Six miles above Bethel, where the river, railway, and road draw closely 
together and sweep around the base of Peaked hill, there is a steep ledge, about twenty 
feet high, close to the track, which is polished and furrowed, both upon the nearly ver- 
tical face towards the river, and also upon a narrow horizontal shelf part way up on the 
ledge. The lines upon the horizontal shelf run S. 20° E., the vertical face standing S. 
25°-30° E. Itis necessary, however, to be guarded in drawing conclusions from gla- 
cial traces left upon vertical or steeply inclined surfaces, as the movement of ice, jam- 
ming through a narrow passage, may be locally disturbed, so as to give a direction to 
the furrows quite different from that of the general movement of the glacier. This was 
most likely the case at the point referred to, as the furrows on the opposite side of 
the hill—z. ¢., the south side—ran S. 80° E., thus according much more nearly with 
the traces, both above and below this point, than the furrows upon the steep face tow- 
ards the river do. The ice would seem to have passed around both sides of this hill; 
and we can readily conceive that this might be, since the depression in the rear, south 
of the elevation, is quite low. Indeed, in the fine view from Sunset Rock in Bethel, 
Peaked hill seems to rise in a very isolated manner from the middle of the valley, which 
makes it a very prominent feature in that magnificent picture. 


* American Naturalist, vol. ii, p. 284. 


GLACIAL DRIFT. 229 


There are no indications of the passage of this glacier below Bethel, 
so far as I had time to search for them. I did not follow down the An- 
droscoggin on the south side, and the north side only to Bear river, 
though I crossed it at Rumford Point. I found evidences of local action 
down Bear river, in Grafton and Newry, and upon Ellis river in Andover 
and Rumford, as well marked as those along the Blackwater in Andover, 
N.H. On the east town line of Bethel, the striz run S. 4° E., and S. 24° 
E. On Paradise hill, south of the village, the course is S.23° E. These all 
correspond to the common course of the drift in this part of the state. 

Saco Valley. A few points of interest manifest themselves through 
the valley of the White Mountain Notch, which may be regarded as a 
local movement. The mountain east, Webster, shows the course S. 
30°-37° E. On the west, Tom, S. 57° E., Field, S. 50° E., Willey, S. 
42° E., corresponding well with the usual south-east course on the high- 
est summits. Mt. Willard, which is really the head of the valley, shows 
distinct strize, more abundant on the slate towards Field, running S. 23° 
E. In the very Notch, by the railroad, the course is S. 20° E. Under 
the Butterwort flume, close by the railroad, at a small house, are glacial 
lines on a mural surface running with the valley ; and on the south side 
of Mt. Willard the course S. 15° E. was measured. On the railroad, by 
the Willey brook, the stria may be seen from the train on both sides, 
and is thought to be southerly, as it certainly occurs parallel to the valley. 
Other markings down the valley directed more easterly, occur upon the 
north side of Frankenstein cliff. Below Bemis a mural surface shows 
similar scratches over a limited area. No other markings have been 
seen. Mt. Washington river shows an immense cliff of rudely stratified 
material near its mouth, comparable with the similar deposit on Peabody 
river produced by the melting of a local glacier. The immense amount 
of boulders and coarse moraine material just below Sawyer’s Rock sug- 
gests detritus brought down by a local glacier. The tributary Duck 
Pond stream, west of Bemis, shows strize upon a mural surface, pointing 
S. 18° E., which may have been connected with the Saco glacier. The 
nature of the rocks, readily disintegrating, and their obscurement by 
débris and forests, render it difficult to accumulate many facts about drift 
phenomena in it; but enough has been seen to indicate the probability 


of the existence in it of an ancient local glacier. 
VOL, III, 30 


230 SURFACE GEOLOGY. 


Tue Latest GLACIERS. 


Having now described the various phases of glacial motion in the state, 
referring all our observations of direction to their various classes, it may 
be proper to introduce a related topic, upon which much might be offered. 
I will content myself with the briefest mention possible. 

The examination of various isolated hills in the south part of the state 
indicates that, as the closing up of glacial action, there has probably been 
a sliding on all sides from the summit, not sufficient to score ledges, but 
enough to push boulders to the base. It is common to find a dome- 
shaped hill, of not necessarily large dimensions, nearly encircled by a 
ring of boulders: The explanation of their presence, as suggested by a 
friend, is, that the ice moved from the summit down the various sides pre- 
cisely like the radiation of local glaciers from lofty mountain ranges. 
The materials transported are what have once been acted upon by the 
ordinary glacial agency. Attention has not been called to this redrrange- 
ment by other authors, as there is nothing striking about it to suggest 
anything different from accumulations brought in the ordinary way. 
This action is akin to that of the local glacier, and where the hills are 
large would be classed with them. 

I had commenced a careful study of this class of hills, when the singu- 
larity of the presence and arrangement of the lenticular moraines began 
to be developed, and led me to devote what time remained to that more 
important subject. I have therefore no well digested facts to present 
upon the later phenomena. I will only point out a few examples of them. 
To properly set forth this subject would require a thorough topographi- 
cal survey, wherein elevations of ten feet would be indicated, as well as 
the character of the surface in all its variations of ledge, peat, meadow, 
forest, cleared and cultivated fields, rocky pastures, etc. 

After beginning to look at our hills in the light of this suggestion, I 
have been surprised to discover how frequent the examples are. Such as 
can be readily recalled will be enumerated. One particular must first be 
specified, wherein these phenomena are scarcely distinguishable from 
others of equal importance. They are like lateral moraines. -In fact, it 
is conceivable that the rubbish sliding down the side of a valley may fall 
upon the edge of a moving glacier, and be pushed along afterwards so as 


GLACIAL DRIFT. 231 


to constitute a true moraine. The observer will call a particular example 
a lateral moraine, or one derived by the later sliding, according to his 
prepossession. For example: in Moultonborough, between Long and 
Round ponds, is a long drift ridge in the middle of the valley parallel 
with Red hill. This may be called the local frontal moraine, sliding 
from the whole western slope of Red hill, or else a lateral moraine of 
ice from the north pushing towards Lake Winnipiseogee. I think this 
example, as it lies fairly in the middle of the valley, is properly a case of 
sliding from Red hill; but Prof. Agassiz refers to this, or one like it, in 
a paper cited a few pages ahead, as a lateral moraine. At the south- 
west end of Red hill, this same moraine changes its direction, conform- 
ing to the slope of the hill. Other illustrations are in the Wildcat valley 
of Jackson, which seem to be the lateral moraines of the ice filling the 
whole valley. 


Near the town lines of Moultonborough and Tuftonborough, next Ossipee mountain, 
are several ridges, mostly gravelly, that seem to have been turned up by ice sliding down 
the elevation. By Mrs. Brian’s they are large and conspicuous, with a south-east course. 
Further south, they begin to trend a little more southerly than is required for perfect 
parallelism with the mountain, and often are a mile long. Near G. Hartford’s in Moul- 
tonborough is a small ridge of drift parallel with the mountain. In the south-east corner 
of Sandwich are quite extensive ridges of till parallel with the Ossipee mountains, and 
having a course about north-east and south-west. On the east side of the same moun- 
tains, from Moultonville nearly to West Ossipee station, is a nearly continuous fringe 
of large, angular blocks of porphyritic granite, such as occurs at the east part of the 
elevation, underlying the granitic breccias. These probably underlie the broad sand 
plain of the Bear Camp river. Green mountain in Effingham is an isolated elevation; 
and I thought at first these granitic blocks at the base of Ossipee came from it, having 
been transported northerly. Rock of similar character occurs on Green mountain, but 
it does not seem to have been carried so far to the north. There are many large blocks 
of granite close by Ossipee pond, at the cross-roads about three miles north-west from 
Green mountain, which probably came from the Ossipee mountains, moving east or 
south-east. The largest one seen is 21 feet long, from 7 to 14 high, and 16 wide. 
Green mountain has a great thickness of hard, compressed till upon its northern flank, 
extending more than half-way up. At its base are some small ridges turned up paralle] 
to the mountain, with the steep slope against the mountain, as would naturally be the 
case if their origin were what is here indicated. The till has usually a smooth surface, 
the loose blocks having been removed from it by the sliding. Some of the striated 
blocks, as at James S. Smith’s, have been deposited in stratified sand. A boulder of 
Ossipee granite over the sand near here is 12 feet in diameter. The thick deposit of 
till is wanting on the south side. 


232 SURFACE GEOLOGY. 


Between Greenfield and Bennington are rows of boulders on the south-west side of 
a large lenticular hill. 

Crotched mountain in Francestown and Bennington may be taken as a good example 
to illustrate the presence or absence of this class of deposits. An attempt to makea 
thorough examination of this elevation was frustrated; but evidences of the moraines 
were seen on the south-west side, consisting of many large, rough blocks and ridges 
on the north-east side of Whittemore pond. Similar blocks occur on the road nearest 
the mountain on its south side. The north-east slope of this elevation is smoothed, as 
if there had been a sliding over the till; but I have not seen the nature of the ground 
at the very base. As it appears uncultivated when seen from a distance, it is probable 
that so much rubbish has been pushed into it from Crotched as to make the land diffi- 
cult of tillage. 

The north side of the New Durham and Brookfield Moose mountain is thickly strown 
with large boulders of granite and schist, obscuring the ledges. 

Various evidences of local sliding appear in the city of Manchester. One is at the 
corner above Brook street. Three layers appear in an excavation, the two lowest ap- 
parently resembling the upper and lower till. The uppermost—of a lighter color—may 
have slid down the hill about the time of the termination of ice action. It is a material 
that runs like porridge when wet. Other similar cases have been removed in grading 
for new streets. The north-west side of Company hill for over a mile shows many mo- 
raine-like windrows parallel with the ridge. These contain more or less boulders, and 
are properly referable to this latest action. Perhaps these moraines should have some 
connection with the north-west course across the rock near the Amoskeag granite 
quarry. On the south-east side of this hill, back of the granite quarries, as we pass 
the pest-house on Bridge street, is another local moraine. Bald hill, near the east line 
of the city limits, furnishes other illustrations, there being two north and south lines of 
moraines upon its east side. On the south slope of this hill are numerous blocks of 
granitic gneiss, situated in a north and south course, reaching nearly to the railroad. 
One of them is 20 feet square. These seem to have been derived from Bald hill. Other 
lines of moraines occur at the south-east base of the Reservoir hill, where the frag- 
ments are angular. 

In Grafton are high hills extending from Prescott’s easterly along the Springfield line. 
A brook flows easterly along their base, turning at an acute angle by a small pond, and 
entering Smith’s river at Grafton station. Within this acute angle are piles of drift 
parallel with the easterly hills south. These may be the rubbish sliding down from the 
south across the brook. 

In Chester, two hills near each other seem to have crowded this loose detritus into 
the valley between. First is the gneiss hill in the north part of the town; and we find 
a line of blocks on its south-east side from Wm. S. True’s round to near North pond, a 
distance of two or three miles. There may have been additions to the moraines from 
the smooth hill south, upon which Chester village is situated. 

In Deerfield, the direct road from Candia to the Centre across a long ridge in the 


GLACIAL DRIFT. 233 


south part of Deerfield descends to a large branch of the Lamprey river, and then rises 
much towards the Centre. On both sides of this stream are lines of moraines parallel 
with the brook, and also with the valley. These are excellent illustrations of this class 
of moraines. How far these moraines would extend along the valley, can be known 
only by further search. Our traverse is simply one section across them. Other exam- 
ples occur in crossing the parallel tributary one mile south from the Centre. 

The hill north of Pawtuckaway pond in Nottingham, on the road nearest to and 
around the mountain, shows lines of moraines parallel to the hill south-west from 
Quincy pond. Some of the blocks are 12 or 15 feet in length. 

In the north part of Fremont is a round hill less than 200 feet above the plain, around 
which are local moraines, especially upon the north-west side. There is a large field 
“of big blocks near the Baptist church on the east side. The east and west road in the 
north parts of Fremont and Brentwood lies over numerous drift ridges and moraines 
essentially parallel with the stream and the higher land to the south. These may not 
be local. 

In Kensington, the lenticular hills in the north-west part of the town show good 
illustrations of the local moraines in the form of many rough blocks and small mounds 
on the north-east side near M. Hobbs’s. Some of the blocks are 20 feet long. This 
example is of a large moraine deposit by the oldest drift, serving for the centre of 
dispersion of blocks at the close of glacial work. 

South of the railroad at Raymond for two miles, chiefly east from the village, are 
many moraines of all sizes, referred to local action, in case the high land to the north 
is regarded as the locality from which they have come. They are as conspicuous as 
most moraines left by the older drift. 


The foregoing are sufficiently numerous to call attention to the subject 
of these late movements of earth analogous to glaciers. In this same 
connection, I desire to describe certain other glacial phenomena of more 
consequence, but which usually do not prove themselves by any strize or 
embossment. They are better examples of ice action than what has just 
been described, but like them, move down valleys and hillsides, smooth- 
ing the ancient hill, and pushing along boulders. It is the action of gla- 
ciers upon material that had already been moved by the continental ice, 
and which belong to a later period still than the valley movements and 
local glaciers. All these glacial movements are described here before 
speaking of the boulders and moraines, so that the subject of glaciers 
may be treated as a unity. This class of facts was first brought out by 
the late Prof. L. Agassiz, who spent much time in their study about 
Bethlehem. I had the pleasure of seeing the phenomena he describes, 
under his guidance, and can testify to the fidelity of his statements. He 


234 SURFACE GEOLOGY. 


communicated to me many other speculations concerning the existence 
of glaciers in the neighborhood, some that I could not indorse; but it is 
very gratifying to see that he published only what would stand the test 
of the most rigid scrutiny. It is to be regretted that he was unable to 
make other further publications, as intimated in the following paper. I 
subsequently searched the mountains, and other parts of the state, for 
facts confirmatory of Agassiz’s views, both as to the special case de- 
scribed and to the further development of similar classes of facts in other 
localities. These facts I will present after reproducing the original paper 
referred to. I find evidence ofa local glaciation in the White Moun-s 
tains, not in the style of sculpture and moraine advocated by Packard 
and Vose, but in the peculiar form of evidence first suggested by Agassiz. 
It required a genius like his to point out the proper method of investi- 
gation. 


Twenty-three years ago, when I first visited the White Mountains, in the summer of 
1847, I noticed unmistakable evidences of the former existence of local glaciers. They 
were the more clear and impressive to me because I was then fresh from my investiga- 
tions of the glaciers in Switzerland. And yet, beyond the mere statement of the fact 
that such glaciers once existed here, I have never published a detailed account of my 
observations, for the simple reason that I could not then find any limit or any definite 
relation between the northern drift and the phenomena indicative of local White 
Mountain glaciers; nor have I ever been able since to revisit the region for more care- 
ful examination. This year, a prolonged stay among these hills has enabled me to 
study this difficult problem more closely, and I am now prepared to show that the drift, 
so-called, has the same general characteristics on the northern and southern sides of 
the White Mountains. Whatever, therefore, may have been the number of its higher 
peaks which, at any given time during the glacial period, rose above the great ice 
sheet which then covered the country, this mountain range offered no obstacle to the 
southward movement and progress of the northern ice fields. To the north of the 
White Mountains, as well as to the south, the northern drift consists of a paste more or 
less clayey or sandy, containing abraded fragments of a great variety of rocks, so im- 
pacted into the minutely comminuted materials as to indicate neither stratification nor 
arrangement or sorting, determined by the form, size, or weight of these fragments. 
Large boulders and pebbles of all sizes are found in it throughout its thickness, and 
these coarser materials have evidently been ground together with the clay and sand 
under great pressure, beneath heavy masses of ice, for they have all the characteristic 
marks so unmistakable now to those who are familiar with glacial action,—scratches, 
grooves, furrows, etc. These marks are rectilinear, but they cross each other at vari- 
ous angles, thus showing by the change in their direction that the fragments on which 


GLACIAL DRIFT. 235 


they occur, though held for a time in one and the same position while these straight 
lines were engraved upon their surface, nevertheless changed that position more or less 
frequently. A few flatter fragments with more angular outlines show only one kind of 
scratches, having evidently been held for a longer time in the same position. This 
drift, however it may vary in its mineralogical components in different localities, ex- 
hibits everywhere the same characteristic treatment over the whole country, from the 
shores of the Atlantic to the Rocky Mountains, and beyond. In the White Mountain 
region it has the same mineralogical character north and south of the range, and rests 
everywhere upon the well known rvoches moutonnées,—in one word, upon the planed, 
grooved, polished, and scratched surfaces of the rocks underlying it. 

Observation has taught us that materials such as those described above, so com- 
bined, exhibiting the same characters in their surfaces, and having the same diversity 
of composition and absence of all sorting or regular arrangement, occur now at the 
bottom of the great glaciers of our time, and nowhere else, being found between the 
ice and the rocks over which it moves,—the result, in fact, of the grinding action of ad- 
vancing glaciers. On account of their unvarying position, I have called these deposits 
‘‘ground moraines,” because they are always resting upon the rocky floor of the coun- 
try, between it and the under surface of the ice. Our typical unaltered so-called 
northern drift is synonymous with the ground moraines of the present day, differing 
only in its greater extension. It is in facta ground moraine spreading over the great- 
est part of the continent. All its characteristics, identical in every detail with those of 
the deposits underlying the present glaciers, show that it can only have been formed 
under a moving body of ice, held between it and the underlying mass of rock. The 
great ice sheet of the glacial period which fashioned the drift must therefore have been 
coéxtensive with the distribution of the latter. It is very important to distinguish this 
drift from the moraines formed under other circumstances, and from the so-called 
erratics and perched blocks. Moraines, as commonly understood, that is, lateral and 
frontal moraines, consisting of loose materials collected along the sides and at the 
terminus of a glacier, always indicate, and, where undisturbed, actually define the mar- 
gins of a moving mass of ice; whereas, the so-called median moraines formed along the 
line of junction of the glaciers are carried upon the back or upper surface of the ice, 
and always consist of angular materials, the shape and arrangement of which are de- 
termined by their mode of accumulation. Just as among the glaciers of the present 
day we discriminate between ground moraines, lateral, frontal, and median moraines, 
so must we also distinguish between the same phenomena in past times. The glacial 
period had also its ground moraines, its lateral, its frontal, and its median moraines, 
its erratics and perched boulders. But the huge ground moraine of the earlier ice 
time stretched continuously, like the ice sheet under which it was formed, over the 
whole country, from the arctics to the Southern states, and from the Atlantic to the 
Rocky Mountains. I do not speak of the western slope of the continent, because I 
have not examined it personally. The great angular erratics of that period were scat- 
tered irregularly over the country, as the few large boulders are scattered on the upper 


236 SURFACE GEOLOGY. 


surface of a glacier now. It is the contact of the more limited phenomena of the local 
glaciers which succeeded this all-embracing winter (their lateral, frontal, median, and 
limited ground moraines and their erratics), with the more wide-spread and general 
features of the drift that I have been able to trace in the White Mountains this summer. 
The limits of this paper will not allow me to do more than record the general facts, but 
I hope to give them hereafter more in detail, and with fuller illustrations. The most 
difficult part of the investigation is the tracing of the erratics to their origin; it is far 
more intricate than the identification of the origin of ordinary drift, or of continuous 
moraines, because the solution of the problem can only be reached under favorable 
circumstances, where boulders of the same kind of rock can be followed from distance 
to distance, to the ledge zz sztw from which they were detached. Now, in the neigh- 
borhood of the White Mountains, we find, beside the typical or northern drift, large 
erratic boulders, as well as lateral, frontal, and median moraines. A careful examina- 
tion of these shows beyond a doubt that they came from the White Mountains, and 
not from the northern regions, since they overlie the typical drift which they have only 
here and there removed and modified. A short description of the facts will leave no 
doubt upon this point. 

The finest lateral moraines in these regions may be seen along the hillsides flanking 
the bed of the south branch of the Ammonoosuc, north of the village of Franconia. 
The best median moraines are to the east of Picket hill* and Round hill. These lat- 
ter moraines were formed by the confluence of the glaciers which occupied the depres- 
sion between Haystack and Mt. Lafayette, and that which descended from the northern 
face of Lafayette itself. These longitudinal moraines are particularly interesting as 
connecting the erratic boulders on the north side of the Franconia range with that 
mountain mass, and showing that they are not northern boulders transported south- 
ward, but boulders from a southern range transported northward. But by far the most 
significant facts showing the great extent of the local glaciers of the White Mountain 
range, as well as the most accessible and easily recognized, even by travellers not very 
familiar with glacial phenomena, are the terminal moraines to the north of Bethlehem 
village, between it and the northern bend of the Ammonoosuc river. The lane start- 
ing from Bethlehem street, following the cemetery for a short distance, and hence 
trending northward, cuts sixteen terminal moraines in a tract of about two miles. 
Some of these moraines are as distinct as any I know in Switzerland. They show un- 
mistakably by their form that they were produced by the pressure of a glacier moving 
from south, northward. This is indicated by their abrupt southward slope, facing, 
that is, toward the Franconia range, while their northern face has a much gentler de- 
scent. The steeper slope of a moraine is always resting against the glacier, while the 
outer side is comparatively little inclined. The form of these moraines, therefore, as 
well as their position, shows that they have come down the Franconia mountains. A 
few details concerning their location may not be out of place, in order that any visitor 


* Since called Mt. Agassiz.—C. H. H. 


GLACIAL DRIFT. 237 


interested in the facts may readily find them without a guide. The ground to the north 
of Bethlehem slopes gently northward, and is not wooded for about half a mile from 
the street. Following the lane above mentioned, the first moraine reached skirts the 
edge of the wood, and is near the houses of Mr. Phillips; there are four others more 
or less distinct before reaching a little trout brook called ‘‘ Barrett's brook.” The lane 
descends more rapidly towards the brook than before, and where the descent begins to 
be steep the eye commands the space between the brook and a higher ground on which 
stands a house owned by Henry McCulloch. Over that interval six very fine moraines 
may be counted, one of which is perhaps the finest specimen of a terminal moraine I 
have ever seen. Beyond McCulloch’s there are five more, not quite as distinct. The 
ground beyond the termination of the glacier of the Rhone in Switzerland is celebrated 
for its many distinct concentric terminal moraines ; but here we have a field over which, 
within the same area, a larger number of such moraines may be seen, and I believe 
that a pilgrimage to this spot would convert many a skeptic to the true faith concern- 
ing the transportation of erratic boulders, especially if he has seen the glacier of the 
Rhone, and can compare the phenomena of the two localities. 

The Littleton road from Bethlehem, and the roads to Franconia Notch from both 
these towns, frequently intersect terminal moraines. Those familiar with the topog- 
raphy of the Franconia range, and its relation to Picket hill and the slope of Bethle- 
hem, will at once perceive that the glacier which deposited the front moraine to the 
north of Bethlehem village must have filled the valley of Franconia to and above the 
level of the saddle of Picket hill, making it at least fifteen hundred feet thick, if. not 
more; thicker, in short, than any of the present glaciers of Switzerland. It will be 
observed, also, that as soon as the northern portion of that glacier had retreated to the 
wall which encircles the Franconia valley on the north, the glacier occupying hence- 
forth a more protected valley within the ranges must have made a halt, and accumu- 
lated at this point, that is, south and west of the saddle of Picket hill, a very large 
terminal moraine. This moraine actually exists to the present day, and is one of the 
most characteristic features of the distribution of erratics in these regions. From the 
moment the glacier was reduced to the level of Franconia bottom, it must suddenly have 
vanished entirely from the whole valley ; and thus it happens that no other large termi- 
nal moraines are seen between that just mentioned and the higher range of Franconia. 

Moraines similar to those observed on the northern side of the White Mountains 
exist also on their southern side in the vicinity of Center Harbor. Lateral moraines 
may be traced at the foot of Red hill, a little above Long pond; also, along Squam 
lake. Median moraines are very distinct near Center Harbor hotel. Terminal mo- 
raines are also numerous near Center Harbor, and in the neighborhood of Meredith. 
At the southern end of Red hill the lateral moraines trend westward, and show their 
connection with the terminal moraines. These facts, taken in their relation with those 
enumerated above, show that there were local glaciers on the southern as well as the 
northern slopes of the White Mountain ranges, moving in opposite directions,—those 
on the northern slope moving northward, and those on the southern slope moving 

VOL. III 31 


238 SURFACE GEOLOGY. 


southward. I have seen no evidence thus far of these northern glaciers extending be- 
yond the range of hills which separates the Ammonoosuc river from the Connecticut 
river valley west of Lancaster, nor have I traced the southern glaciers beyond Lake 
Winnipiseogee. Traces of an eastern glacier moving westward may be seen near the 
Twin Mountain house; but I have not examined that region with sufficient care to give 
minute particulars. 

All these moraines and traces of local glaciers overlie the typical or northern drift, 
so-called, wherever the latter has not been swept away by the local glaciers themselves ; 
thus showing that the great ice sheet was anterior to the local glaciers, and not formed 
by a spreading of preéxisting glaciers. At least, wherever I have recognized traces of 
circumscribed glaciers in regions where they no longer exist, it has always appeared to 
me that the minor areas covered by ice were remnants of a waning sheet of greater ex- 
tent. If the glacial period set in by the enlargement of limited glaciers already formed 
and gradually spreading more and more widely, as Lyell and the geologists of his 
school suppose, the facts which would justify such a view are still to be made known. 
I have not seen a trace of them anywhere. On the contrary, throughout the ranges of 
the Alps, in the Black Forest, the Vosges, as well as in the British islands, in Scot- 
land, Wales, and Ireland, I have everywhere satisfied myself that the more extensive 
the glaciated areas indicated by polished surfaces and moraines, in any given locality, 
the older they are when compared with glacial phenomena circumscribed within nar- 
rower limits. 

It therefore follows from the facts enumerated above, as well as from a general con- 
sideration of the subject, that the local glaciers of the White Mountains are of more 
recent date than the great ice sheet which fashioned the typical drift. On another 
occasion, I hope to show that the action of the local glaciers of the White Mountains 
began to be circumscribed within the areas they covered, after the typical drift had, in 
consequence of the melting of the northern ice sheet, been laid bare in the Middle 
states, in Massachusetts and Connecticut, after even the southern portions of Vermont, 
New Hampshire, and Maine had been freed, and when the White Mountains, the Adi- 
rondacks, and the Katahdin range were the only ice clad peaks in this part of the con- 
tinent. 

When in their turn the glaciers of the White Mountain region began to melt away, 
the freshets occasioned by the sudden large accumulation of water remodelled many of 
these moraines, and carried off the minute materials they contained to deposit them 
lower down in the shape of river terraces. I have recently satisfied myself, by a care- 
ful examination, that all the river terraces of the Connecticut river valley and its tribu- 
taries, as well as those of the Merrimack and its tributaries, are deposits formed by the 
floods descending from the melting glaciers. What President Hitchcock has described 
as sea-beaches and ocean bottoms near the White Mountain and Franconia Notches, 
as well as in the Connecticut river valley and along the Merrimack, have all the same 
origin. The ocean never was in contact with these deposits, which nowhere contain 
any trace of marine organic remains.—American Naturalist, vol. iv, p. 550. 


GLACIAL DRIFT. 239 


LocaL GLACIERS IN THE WHITE MOUNTAINS. 


I will now present whatever additional facts may be known respecting 
the existence of former glaciers radiating from the White Mountain high- 
lands. We have seen that my father and Prof. Agassiz agreed as to the 
nature of the glacial markings upon the mountains,—that they belonged 
to the older and continental sheet, a south-east movement proceeding up 
hill whenever obstacles made it necessary. The markings described by 
Packard and Vose, claimed to have been the result of local glaciation in 
the Peabody valley, have been shown to belong to the older movement. 
The others mentioned by Packard in Jackson are properly local, and will 
be described presently. 

In order to prove that glaciers have radiated in all directions from the 
White Mountains, it is necessary to find evidences of northerly or north- 
west motion. Evidences of valley movements towards the south-east can 
easily be referred to the general south-east movement, modified slightly 
by the topography. If nothing else could be found, the doctrine of the 
existence of local glaciers would depend upon unreliable evidence. The 
researches of Agassiz about Bethlehem were the first in this direction in 
New Hampshire. He found evidence of a movement opposite to that of 
the general drift. Hence this must have been different from the com- 
mon drift, and, taken in connection with the other features described, it 
was found to have been local, and existed in the decline of the ice period 
after the continental sheet had mostly disappeared. The action was 
rarely sufficiently energetic to score the ledges. Agassiz does not rely 
upon that class of evidence in maintaining his position. The ice of this 
Franconia-Bethlehem movement has passed over ledges, but has not 
smoothed or striated them. The boulders which went southerly in obe- 
dience to the south-east movement were simply pushed back towards 
their source ; and we find very few cases of their protrusion beyond their 
starting-point. I will first add whatever observations I can in elucidation 
of this specific example, and then describe the other observed facts seen 
nearer the mountains. 

The starting-point of this glacier was in the prominent valley back of 
Eagle Cliff, on the north-west flank of Mt. Lafayette. This was visited 
by my father in 1851, and a sketch of the phenomena seen described 


240 SURFACE GEOLOGY. 


soon afterwards.* It appears that in 1850 a powerful rain soaked the 
débris in this valley so that it slid a considerable distance downwards, 
and left deposits analogous to moraines, but did not materially engrave 


the ledges. 


At the head of the slide we saw a mass of naked gneiss rock many rods wide, mostly 
denuded of soil, and much of it also of several layers of the rock, which had slid down- 
wards, and were strown along the sides of the ravine for at least two miles. This naked 
surface, at its upper part, had a slope of about 38°. Lower down, however, it was 
much less, for the most part, and at its termination the descent was slight. * * * 
It was just such an example as I had long wished to find. An enormous mass of detri- 
tus, probably from ten to twenty feet thick, and in some places two or three rods wide, 
composed of irregular fragments of all sizes, from twenty feet in diameter down to 
sand, had been driven forward over a rocky surface two miles long. What, now, was 
the effect upon the rocky floor? Did it score and striate the floor, as was done by the 
drift agency, as some suppose would be done by the crowding forward of detritus by 
the power of water? I found it was not so. The rock in place was smoothed but not 
striated, except in a few places, perhaps in the slightest manner. The fundamental 
rock passed over is gneiss, but it is traversed occasionally by veins of granite, and 
towards the upper part by dykes of trap several rods wide. They are such rocks as in 
various places retain distinct markings of the drift action. The beds of detritus pro- 
duced along this slide are so closely like those of glacial origin that we may call them 
moraines. They are larger and more distinct than I have seen on any other slide. All 
along the borders of the ravine are ridges of blocks, gravel, and sand, sometimes 
twenty feet high, lying in as much confusion as is possible, and making it difficult and 
even dangerous to go into or out of the ravine over the loose and crumbling ridges. 
At the lower end of the slide is a large terminal moraine, by which the river has been 
forced to seek a new channel. This terminal moraine is, in fact, double; that is, an 
old moraine lies in advance of that produced by the slide of 1850, the blocks of the 
two being easily distinguished by the appearance of recent or more ancient erosion. 
In short, the appearances along this gulf are almost precisely what they would be if a 
glacier in one of the valleys of the Alps should melt away. And when examining it, I 
had no doubt that the slide was produced by the advance of a mass of ice; yet I no- 
ticed that, in some places, the lateral moraine was driven in among the trees without 
affecting them. In some places near the bed of the slide I noticed the stumps of trees, 
perhaps six inches in diameter, that had been broken off by the descending mass. 


This valley was regarded by Agassiz as the source of that glacier. In 
confirmation of it, boulders of Franconia breccia like the ledge compos- 
ing Eagle cliff, have been found near J. McDonald’s, in Franconia, at 


* Am. Your. Science, ii, vol. xiv, p. 73. 


GLACIAL DRIFT. 24! 


the end of a road on the direct line between the cliff and Bethlehem 
street. The distance of their transportation is about two miles, and no 
locality of this rock is known to exist nearer McDonald’s than Eagle 
cliff. Many of these blocks are four feet in length. The ledge near 
here does not show any ice marks from the local glacier, but there are 
appearances upon it of the usual south-west movement of the neighbor- 
hood (page 211). North of McDonald’s, towards Gale river, the surface 
of the drift is smooth and nearly flat. This is to be explained by the 
passage of the ice over it, as in Bethlehem. Near the western edge of 
this flat expanse is a moraine running N. 27° W., about 20 feet high 
and 40 rods long. It is thought to have been connected with this Beth- 
lehem glacier, as a medial or lateral moraine. The hill slopes rapidly 
just west of the moraine,.and has many quite large boulders scattered 
over it. 

Between Bethlehem street and Littleton is a Baptist church, near 
which I observed boulders 15 feet long, 10 wide, and 10 high, whose 
source is estimated to be from 300 to 500 feet to the south up hill. Their 
transportation down this slope I ascribe to the same local glacier. 

There are numerous moraines commencing a few rods east of Littleton 
railroad station, probably put in their present position by ice of this or a 
related glacier. The eastern slope of the hill between Bethlehem street 
and station is thickly strewn with large boulders, of material similar to 
the nearest ledges. Their position is suggestive of transportation down 
the Ammonoosuc from the east. As similar rocks occur as far as the 
Twin Mountain house, it is not unlikely that the Ammonoosuc glacier 
brought them there; but further study is required to demonstrate the 
proposition. 

Ammonoosuc Glacier. We have a few facts in regard to the move- 
ment of rocks down the Ammonoosuc valley, probably caused by a local 
glacier. The ice transported boulders far below Bethlehem station, so 
that abundant proof exists of the existence of a glacier close by the 
gneissic blocks just mentioned, on the east slope of the Bethlehem hill. 
The source of this movement was in the large valley occupied by Con- 
cord granite, between Fabyan’s and the Presidential range. Many large 
blocks of a coarser-grained granite than ordinary lie upon the slope of 
Mt. Deception, just opposite the Fabyan house, and along the turnpike 


242 SURFACE GEOLOGY. 


for a mile easterly. These have not travelled far, having been derived 
from the south base of Mt. Deception. One piece is 22 feet long, 14 
high, and 10 thick. Those 6 feet in length are common. The frag- 
ments are too far removed from the mountain to have accumulated 
merely by gravity. A similar moraine is cut by the railroad just below 
the White Mountain house at the head of the falls in the Ammonoosuc, 

The recent clearings disclose a sharp, conical moraine south of the Mt. 
Pleasant house, perhaps 20 feet high, and very different in character from 
the neighboring mounds of esker and river gravel. The many large 
granite blocks, where the railroad approaches near the Ammonoosuc 
river, above Mt. Pleasant and near the upper falls, are also like a local 
moraine. 

In the fields east of the Twin Mountain house there are hundreds of 
boulders of Mt. Deception granite, often 12 feet in length. The under- 
lying rocks, for the four or five miles distance between the Twin Moun- 
tain house and Fabyan’s, are of very different material. Hence this is 
an example of materials transported westerly a distance of four miles. 
This cannot have been done by water,—the blocks are too large. A 
local glacier sliding over the more ancient drift must have been the agent 
of transportation. This lateral moraine east of the Twin Mountain house 
is quite conspicuous, and the most readily accessible of any examples 
known. It may be seen from the train, a short distance east of the 
station. 

Just west of Rounsevel & Colburn’s saw-mill, midway between the 
Twin and White Mountain houses, I found a large block of granite, in 
1871, nearly 12 feet in diameter, and about square, closely resembling a 
handsome variety of granite occuring on Mt. Willey, and further south. 
A second smaller one exists in the neighborhood. I have never found 
this particular kind of granite north of the Notch in ledges, and as it 
occurs with the Conway granite near Mt. Willey, it is probable that these 
blocks descended the New Zealand valley, starting from the west side of 
the same mountain. Other boulders, seemingly from the south, are a 
few of Chocorua granite near the Crawford house, in which Prof. Dana 
discovered grains of chrysolite. I know of no ledge to the north of their 
present situation from which they could have been derived, while similar 
ledges abound farther south. 


GLACIAL DRIFT. 243 


Examples of transported boulders of Albany granite are more decisive 
of a glacial movement down the stream. From the mouth of New Zea- 
land river nearly to Bethlehem station are numerous blocks of this gran- 
ite, six feet in length. This rock is in place on the New Zealand river, 
but not on the Ammonoosuc. Hence the fragments must have moved 
down the stream (also Little river, in Carroll), and being too large for 
water transportation, require the agency of a glacier. Rude strie, sup- 
posed to have been made at this period, occur near the Wing road in the 
river. The boulders are found as far south as North Lisbon. I obtained 
a specimen there weighing about eight pounds. No search has been 
made for them lower down. Their location in the river, and angular 
shape, indicate transportation by a local glacier. About half a mile 
above Bethlehem station the valley is almost closed by a large hill of 
till, with some stratified layers on the outside. This eminence resem- 
bles a moraine. 

On Little river, about four miles above its mouth, is a slide worthy of 
mention. For a distance of 50 rods the ledges are bare, where they have 
been exposed by the sliding, commencing at a point and expanding to 20 
rods width. At the base of the hill are 10 rods space as long as the 
width of the slide, full of fallen trees with their trunks mostly arranged 
in convex order, opposite the direction of transportation. No other feat- 
ures of local motion were apparent in the Little River valleys, largely 
because a dense forest prevents them from being seen, or else the power 
exerted in this slide was not sufficient to score the exposed ledges. It 
is probable that the Bethlehem and Ammonoosuc glaciers united and 
flowed down the latter stream several miles below their junction. 

River Moraines. In the Saco valley the tributary streams have 
brought down immense masses of large boulders that would be called 
moraines elsewhere. They cross the main valley like terminal moraines, 
The larger the tributary the more important the deposit. They are par- 
ticularly conspicuous at the mouths of Bemis and Davis brooks, Nancy 
and Sawyer’s rivers. The latter deposit has been cut through bya rail- 
road excavation. This is the most conspicuous example. On descend- 
ing the valley by the carriage-road, we approach a broad expanse of the 
terrace where are one or two farms, and also the turning off of the branch 
railroad to Livermore. The highway ascends a sort of terrace, and the 


244 SURFACE GEOLOGY. 


railroad cuts into it, rising somewhat. At the excavation, the nature of 
the material is well shown, consisting of smooth boulders, from pebbles 
to boulders two and three feet in diameter. The bed of the river shows 
similar detritus. The stream is so violent in high water that these boul- 
ders are pushed downwards, and as the force of the current abates the 
detritus accumulates by the sides. The amount brought down is so 
great that it rises higher than the meadow, and thus we have a deposit 
analogous to that of the levee near the mouth of the Mississippi. The 
tributary stream causes this very coarse deposit to form a ridge reaching 
nearly across the Saco valley, and at right angles to it. Hence it simu- 
lates the terminal moraine of a glacier, and might easily be mistaken for 
one, if the connection between its presence with the tributary were not 
noticed. 

Below Sawyer’s rock this coarse material exists in such amount that it 

is difficult to decide whether it should be called a glacial or a river mo- 
raine. The rubbish has accumulated in the eddy behind the ledge, and 
can be called by either name. It must be 50 feet thick, and cover half a 
square mile of surface. It seems to have been excavated at Stillings’s 
*old hotel stand by Albany brook from the south, and the moraine be- 
tween this stream and Upper Bartlett station is of large size. The rail- 
road cuts through a similar bank on the north side of the Saco, about 
opposite the mouth of Stony brook in Hart’s Location. 

I have already mentioned a few examples of striae on the ledges in the 
valley of Saco river and its tributary, Duck pond, which are referable to a 
local glacier. Through most of Bartlett the land is flat, as if all the rub- 
bish that usually occurs in the form of terraces had been washed out. 
The soil is sufficiently good to enable farmers to cultivate it extensively. 
For a mile and a half along Burbank and Cow brooks, there is a ridge of 
coarse material comparable with a lateral moraine. It is where detritus 
would be naturally deposited, as the river begins to bend northwardly. 
Where the Saco runs northerly to meet Rocky branch is another mo- 
raine pile, at the angle formed by the meeting of these two streams. 
Below this point the valley widens into the broad gravelly meadows of 
Lower Bartlett and Conway, which have been previously described 
(p. 143). Dr. Bemis points out at the base of Mt. Crawford a granite 
block, as much as 12 feet in cubical dimensions, now in the middle of 


GLACIAL DRIFT. 245 


the meadow. This came from the cliff 500 feet above the plain a few 
years since, and after striking the meadow bounded a distance of 10 rods 
to the spot where it now lies. A series of moraines occurs at the saw- 
mill on Rocky branch, and for half a mile above. 

Ellis River Glaciers. A recent visit to the main Ellis river and the 
Wildcat Branch in Jackson enables us to describe the markings left by 
the ice in its descent. Dr. Packard has called attention to them in a 
paper cited above. He gives scarcely any details, and relies upon the 
course of the striae, mainly, for the proof of the existence of the local 
glaciers. These have been credited to him in the table of strie. One 
remark is of importance: “Riding up the Conway valley, up through 
Bartlett to Jackson, we observe moraines innumerable rising high up the 
sides of the valley, and, covered with boulders, revealed more distinctly 
in all the cleared lands. Above these moraines rise rounded and em- 
bossed rocks, while the evenly terraced valley shows that the river, then 
a series of broad lakes, redrranged and re-sorted the compressed mate- 
rials composing the mounds left by the melting glacier into finely, evenly 
stratified fresh water deposits.” I noted some of these moraines in Bart- 
lett, or the edge of Conway, in the woods south of the Interval station. 
Mr. Bigelow’s fine summer residence is upon one of these moraines ; and 
the blocks are quite numerous among the pine trees further south. The 
striz S. 60° W., observed by Vose on the south side of Mt. Pequawket, 
must have been made by a branch from the east. After reaching the 
Ellis valley, there is a proper moraine of a local glacier just below Good- 
rich falls. In the edge of Jackson is a ridge in the middle of the valley, 
about an eighth of a mile long, with many large boulders upon its sur- 
face. Small cuts in it show the presence of some boulder clay. This 
reaches nearly to the bridge across the Ellis river, shortly below the en- 
trance of the Wildcat Branch, and in a proper medial moraine. On 
reaching the village of Jackson, the valley divides; and I will first refer 
to the glacial traces seen on the main stream. There are large moraines 
upon both sides of the valley north and south of a large boarding-house, 
perhaps an eighth of a mile west of the falls. Those south are at the 
base of Cobb’s hill, and are less important than those on the other side. 
About two miles up the valley are lateral moraines. About opposite the 


mouth of Miles brook the ledges show striae running down stream, and 
VOL. Ill. 32 


246 SURFACE GEOLOGY. 


have been abundantly rounded, producing the phenomena of emboss- 
ment. Better examples occur higher up. The last notable example of 
the same is to be seen close by N. H. Cook’s, or the last farm-house in 
Jackson. There is here somewhat of an expanse, while above the de- 
scent is greater, and no intervals can be seen. A careful examination 
of this valley will disclose many more facts, both in the settled and for- 
est portions. On reaching the height of land in Pinkham Notch, we 
approach the Peabody valley, and find marks of a movement up the val- 
ley towards Ellis river. The ice travelled a little west of south, north of 
the water-shed, but east of south in the Ellis valley. It is difficult to say 
that the movement in the Ellis valley was disconnected with that in the 
Peabody. It is likely that, in the earlier glacial times, the course was 
first west and then east of south, while in the decline of the period the 
ice ceased to flow from the Peabody into the Ellis valley. There may 
have been a local northerly movement in the Peabody valley, also, as 
suggested by the enormous terrace, in the south part of Gorham (p. 210). 

The marks upon the Wildcat Branch have been more carefully exam- 
ined, although the scoring of ledges is less common than on the main 
stream. At the top of Jackson falls are many moraines supposed to be 
terminal, and of the last valley movement. An exatiihation of their com- 
position shows them to be a miscellaneous accumulation of ferruginous 
earth and rough stones of granite and schist. There has been no ar- 
rangement of the different sorts by aqueous deposition; it is an unstrati- 
fied pile. Its red color arises from the extreme oxidation and hydration 
of the mass. The material corresponds closely with that of the upper 
till of the older drift, which we shall describe more fully presently. The 
origin of the two deposits is believed to be the same. These moraines 
cross the valley, and are about 140 feet above the bridge between the 
hotels. The next set of terminals jut out into the valley half a mile be- 
yond, and probably once stretched across it. Near J. Gale’s is another set, 
215 feet above the bridge. On the west side of the valley, large, rough 
blocks of stone are common, while the east is smooth. A fourth moraine 
appears at the two Elkins’s houses, a mile and a quarter from the bridge. 
The fifth example is near D. Gray’s, shortly before coming to the road 
leading towards Black mountain. These moraines are lateral, and there 
is a slight depression between them and the hill west. There are many 


GLACIAL DRIFT, 247 


rough blocks near the road on the east side of the valley, on the south 
flank of Black mountain, which are to be regarded as lateral moraines, 
opposite to those mentioned at Gray’s, but higher up. 

A sixth set of moraines crosses the valley at a new saw-mill near Mrs. 
E. Gray’s, two and a quarter miles north of the bridge, and 255 feet 
higher. Above this point the valley keeps the same contour as far as 
Johnson’s mill, 150 feet higher, and more than a mile distant. No well 
marked local phenomena display themselves here, nor higher up, along 
the carriage-road. Possibly a search in the wooded tract adjacent to the 
stream might reveal something interesting above Johnson’s. A cut in 
the drift here shows it to belong to the lower till. Opposite L. Went- 
worth’s, nearly a mile above Johnson’s, is an esker, or kame, 1,000 feet 
long, which may have originated during the melting of this glacier, and 
is thus one of its evidences. On reaching Grant’s (Breck, on map) the 
present road ceases, but the valley might be followed further to the 
north-west. Here are striae quite varied in direction. The face of the 
rock is smoothed in the direction of the valley a trifle west of south, 
crossed by faint irregular lines S. 33° and S. 83° E. These would be 
explained by calling the smoothing the direction of the ice down the 
valley, and the strize caused by a local tributary sliding from the western 
flank. The top of the ledge, where there is freedom from local currents, 
displays the course S. 44° E,, the normal direction of the ancient drift, 
pointing nearly to Mt. Washington. The Wildcat shows other interest- 
ing phenomena of local action further north, but I have not been able 
to examine them. I will add notices of them from Nowell and Sweetser. 
The slide described by the first properly belongs to one of the tributaries 
of the Peabody river glacier. 


W. G. Nowell has given estimates of the position and dimensions of a slide upon the 
west side of Carter Dome, Vol. I, Apfalachia, p. 83. 1 condense his account. The 
date was the same with that described upon the west side of Tripyramid. Mr. Thomp- 
son, the proprietor of the Glen house, lost his life in this freshet, while managing 
affairs at his saw-mill. The top of the ‘‘ hopper,” where the sliding commenced, is 
1200 metres from the summit. It descended N.N. W. 300 metres, dropping 110 me- 
tres ; then fell 140 metres in a course of 400 metres due north; next moved 500 metres 
W.N. W., descending 110 metres, and continues only 100 metres further. For the 
principal part of the last 700 metres the ledge is perfectly bare from 30 to 60 metres in 
breadth, and has piled up at its base about twenty square acres of rubbish that had 


248 SURFACE GEOLOGY. 


come down the mountain. The greatest angle of descent, 42°, occurs in the upper and 
lower of the four sections, and the least angle of 18° is in the third section from the 
top. The minimum widths of the four sections are 10, 15, 20, and 30 metres; the 
maximum 15, 20, 30, and 90 metres. The minimum depths of the excavation were 15, 
10, 5, and 3 metres; the maximum 18, 15, 10, and 10 metres. 

Mr. Sweetser, in his guide-book, speaks ofa line of boulders in the Carter Notch 
which may have had some connection with glacial action. At the south entrance of 
the Notch is a lofty line of immense boulders, piled on each other in inextricable confu- 
sion, and affording some of the most remarkable rock scenery in the mountains. They 
are rugged and deeply pitted, like the rocks on the cone of Mt. Washington, and 
may have been derived from the crests of the adjacent peaks. One or two of these 
boulders are near seventy feet long each. 


Returning to Jackson, we find a tributary of the Wildcat coming from 
the north-east, and uniting with it about a mile above the falls, which 
ought to show a few glacial traces. I found nothing very characteristic, 
unless it were a few boulders of a peculiar porphyritic granite. I think 
these must have been derived from the north, as nothing like them is 
known in ledges west of Mt. Baldface, or “Peaked,” a summit so called 
by Packard, and not named upon our map. The striz upon these moun- 
tains do not point towards Jackson, as they belong to the older set. Mr. 
Packard says,—“On the summit [of Baldface, where the striz run S. 
23°-28° E.] rest several angular boulders of a peculiar porphyritic sienite, 
containing curious oblong crystals of albitic feldspar. Our guide to their 
and, by 
investigation, he found the rock zz szt# upon that eminence. The por- 
phyritic boulders found by me did not come from the mountains men- 
tioned by Packard, as the rubbish derived from them would have gone 
down the east branch of the Saco, joining the main stream in Lower 
Bartlett. Further search will develop evidences of the existence of this 
glacier in the east branch. Packard speaks of staurolite mica schist 
boulders on the north flank of Mt. Pequawket, saying “they must have 
been borne down on the back of the glacier from Mt. Washington.” 
This is hardly probable, since the rock occurs on both the north and 
south sides of Pequawket, and the boulders are even more abundant on 
the south side of the mountain. Jackson Falls village is situated in a 
hopper-shaped depression considerably open on the west side. Pickett, 
Thorn, and Tin mountains constitute the north and east rims, Black and 


” 


source—the trusty ice grooves—points to Peaked mountain; 


GLACIAL DRIFT. 249 


Eagle the north and west sides, while Copp’s hill on the west very nearly 
completes the circle, with rifts for the entrance of the ice from Wildcat 
and Ellis rivers. On nearly every side the material low down consists 
of an immense thickness of till, cut deeply by small streams. This de- 
posit gives an evenness of slope to the hills about Jackson that is uncom- 
mon among the mountains. It is believed that the till is mainly of 
ancient glacial origin brought from the north-west, and that the latest 
ice movement smoothed it over and left many large blocks of stone and 
small moraines. The north slope of Pickett hill shows several examples 
of what appear to be local moraines. Packard speaks of a block of 
many tons’ weight upon a hill near Goodrich falls brought in this way 
only a few rods. In the neighborhood are striz pointing S. 17° W., as 
if connected with the valley movement just mentioned down the tribu- 
tary of the Wildcat river.* 

Pot-holes. In northern New England there are many examples of pot- 
holes worn in ledges far away from existing streams. These are believed 
to have been formed by currents of water derived from the melting ice- 
sheet, passing down the crevasses of the glacier. Those on the summit 
between different valleys were formerly referred to the agency of one of 
the rivers pouring over the divide into the other depression. Many of 
our examples are so situated that such a theory would not explain them. 
I append a list of the principal pot-holes that have come to my notice: 


One 4 feet deep on top of Swett’s mountain, Gilmanton. 

One of large size in Wentworth. It is on the south-west side of Carr’s mountain, 
from 300 to 500 feet above Baker’s river. 

In the ‘‘ Flume,” Dixville, I saw one, 4 feet in diameter and 7 feet deep, in the pro- 
cess of formation. 

On a ledge exposed for 200 feet, near its south end, a conical one, 2 feet in diameter 
at the top, and about 2 feet deep. It is 125 feet above the river at East Weare, and in 
the edge of Dunbarton. It is called ‘‘ Indian mortar” by the people living in the neigh- 
borhood. 

The same name is applied to a pot-hole near the top of Beech hill in New Hampton, 
about 600 feet above the valley of Lake Wukawan. It is situated on the south-western 
peak, not quite so high as the other, and perhaps 15 rods south of and 4o feet lower 
than the highest point. There are no other evidences of water action on the ledges of 


* IT have assumed that Packard’s observations were not corrected for the variation of the compass, 


as he does 
not say anything about it. 


250 SURFACE GEOLOGY. 


porphyritic gneiss than this, and they fall off precipitously for 200 feet. The mortar is 
24 feet from the edge of the rock. It is not perfect, as a notch is gone on the south 
side, so that the cavity is shaped like a pitcher with the nose broken off. The width 
across the top is 1 foot 3 inches; depth, on the north side, 23 feet; depth below the 
notch on the south side, 14 feet. The bottom is rounded, and it is frequently filled 
with water. 

Mr. Upham has described the pot-holes of the Orange and Newbury summits, and 
Warwick, Mass., on pages 63-66. 

At Amoskeag falls, Manchester, on the Merrimack, are several pot-holes; one of 
them is 12 feet in diameter and 25 deep. 

The ‘‘ Purgatory,” on the line of Lyndeborough and Mont Vernon, shows other pot- 
holes. The stream—ro feet wide—winds spirally through a narrow chasm, and then 
falls 15 or 20 feet into a large pool. Both the spiral course and the pool are to be 
classed with pot-holes, and there are several small examples above the main cataract. 
A cave below is thought to have originated from ordinary disintegration through 
freezing. 

Local Movements tn Vermont. Besides the tributaries of the Con- 
necticut glacier already mentioned, I will speak briefly of the other val- 
ley movements occurring in the area of our map. There has been an 
easterly movement up the valleys of the Lamoille, Missisco, and Winoos- 
ki, perfectly distinct from the general south-east progress of the conti- 
nental sheet. It seems to have been a modification of the south-east 
current, caused by the contour of the country, and in no sense a local 
glacier. They are to be compared with the movement of the ice up the 
valley of the Peabody river (p. 208). 

I found excellent local glacier phenomena in the valley of Lincoln 
brook, a tributary of Mad river in Warren. In Plainfield, boulders of 
granite seem to have been transported north-westerly to the main village 
from Harris and Goshen gores. Other cases are probably Trout brook 
in Montgomery, and near Lake Memphremagog from the west. 


Lake BAsInNs. 


One of the evidences of glacial action is seen in the hollowing out of 
basins in the solid rock, which are now occupied by lakes or ponds of 
fresh water. If one travels around the border of certain lakes, he will 
discover that it is everywhere rock-bound. In considering the possible 
methods of excavation of such a basin, some cannot be accounted for 
except by glacial action. We should consider, first, whether it might be 


GLACIAL DRIFT. 251 


a synclinal basin; second, whether it might result from the removal of a 
soluble mineral like limestone. Running water excavates rocks only 
where a descending current can act; hence it could never remove any- 
thing from beneath its level. Ordinary lake ice cannot excavate beyond 
a few inches below water level. Nor could the ocean, if it were present, 
excavate any deeper. There is no other agent left for us to employ, 
except the glacier. When this starts, having a strong force to urge it 
onwards, it will plough out rocks in its descent, and then move up hill. 
This sort of denudation is fitted to excavate lake basins. 

There are numerous examples of these basins excavated out of the 
rock for lakes and ponds in our state. I purposed to make a catalogue 
of them, to be presented here, specifying all whose outlet flowed over 
ledges, and those where till or modified drift constitute the barrier. I 
found, on studying the subject, that a barrier of lower till would keep in 
the water as well as a ledge, so that the enumeration of ponds kept in by 
barriers of rock or till made little practical difference as to the stability 
of the water. Furthermore, a lake may be essentially kept in by a rock 
barrier, while the drift spreads an additional obstacle to the flowage out- 
wards; and, as scarcely any examples could be found of ponds kept in 
by barriers of loose materials, it may not be necessary to present a for- 
mal catalogue of the nature of outlets, citing, instead, a few familiar 
examples. 

Geological treatises make mention of Runaway pond in Glover, Vt., 
where a sandy barrier led to the sudden outrush of the water, after an 
attempt made to increase the size of the outlet by excavation. Similar 
floods have occurred recently by the removal of artificial dams, as in the 
well-known Mill River disaster near Northampton, Mass. We have a 
record of a similar flood on the Mascomy river, occasioned by the burst- 
ing of the original barrier of the lake at East Lebanon. The loose ma- 
terial was not abundant, so that little damage resulted. The Northern 
Railroad company have since renewed the barrier with better material, 
It is an interesting circumstance to recall the ancient barrier of till about 
a quarter of a mile below the present outlet (p. 216), whose removal in 
pre-historic times may have caused a great freshet. In Warren, the 
signs of the bursting of a barrier in ancient times are very distinct. A 
gravel ridge like a kame crossed the valley of Black brook, damming the 


252 SURFACE GEOLOGY. 


stream and producing a pond. What circumstances destroyed this bar- 
rier are not known, but the former existence of the pond attracts univer- 
sal belief. Another case is in the edge of Lyman below Young’s pond. 
A new road follows the stream above the saw-mill, and the gravel hills 
on both sides for a quarter of a mile look as if they had been cut apart 
within the memory of the inhabitants. An old shore line, marking the 
former height of the pond, is still quite conspicuous. As one passes the 
south end of Station pond in Springfield, he is at a loss to see why the 
water does not immediately make an opening for itself towards New 
London. Upper Beech pond in Wolfeborough is an example of an exist- 
ing pond kept in by a deposit of loose gravel (p. 128). There are many 
instances of ponds in gravel plains kept in by loose materials when the 
amount of water is not sufficient to lead to a sudden removal of the bar- 
rier. Such are indicated on the general map by the absence of any outlet. 

Our largest lake,—Winnipiseogee,—must be a rock basin, although no 
ledges appear at its outlet (p. 121). The land falls off abruptly for about 
1400 feet at the Weirs, in slopes say 600 feet long on the north-west, and 
800 on the south-east of the middle of the channel, the amount of the fall 
being nearly 80 feet. As one looks at this from the east it resembles a 
gorge excavated by running water, and it would not be strange if the 
till had once been continuous across the present outlet. In that case 
the outlet would have been from Alton bay towards the Cochecho river. 
The present channel has been deepened about a yard by the Lake com- 
pany. About 25 feet of till has been removed by erosion at the outlet 
of Newfound lake. 

The majority of our ponds have ledges at their outlets. Those who 
are interested in the subject can ascertain whether a given example has 
been excavated from the ledges by observing the nature of the outlet. 
It is very often the case that no ledge is visible about a pond, save where 
the water discharges itself. If any dams are constructed upon loose 
gravel or sand, it will be well for those interested in the integrity of the 
works to examine them from time to time. 


DISPERSION OF BOULDERS. 


The second part of our subject relates to the removal of fragments of 
stone from their original ledges, and to any peculiarities that may be 


GLACIAL DRIFT. on3 


observed in their position, shape, size, distance and direction of trans- 
portation, etc., including the various kinds of moraines. The striation is 
believed to correspond in direction with the course taken by the frag- 
ments in their travels. The stones usually proceed in right lines from 
their sources, at first in large rough blocks, then showing more abrasion 
and less size, till they have been reduced to pebbles or coarse gravel, 
and finally no traces can be seen of them. 

This method of dispersion shows miners how to search for veins of 
valuable ores. If blocks of copper or lead ore show themselves tempt- 
ingly, the country may be searched in the direction of the drift common 
to the neighborhood, usually visible on ledges near by in striz. Let the 
country be carefully explored in the direction whence the stones have 
proceeded, and when no more can be found, the soil may be removed, 
and the veins will show themselves. This method of search, both for 
veins and beds of rock, has been constantly employed in the conduct of 
the geological survey, and the principle has never been found incorrect. 
The existence of many peculiar ledges would never have been discovered 
had not attention been first drawn to certain singular boulders. 

If we were to take up the drift deposits one by one, or town by town, 
and specify what kind of boulders occurred, and what seem to have been 
their sources, much labor would be required, and the details would not 
be interesting. When the geology of the state is perfectly understood, 
those conversant with it will be able to say whence every stone found 
anywhere within our limits has been derived. The general law of the 
‘dispersion of the fragments may be thus stated: the boulders have been 
transported in the direction in which the ice of the glacier period moved, 
as indicated by stria. By consulting our table of striz, where nearly 
every town is represented, those seeking to learn the origin of interesting 
stones in their neighborhood may learn the probable point of compass in 
which to travel to find the source of their specimens. I will endeavor to 
state presently any exceptions to the above rule known to exist. 

‘The teachers of the institute at New Hampton have interested their 
classes in this subject, and the young people have left behind monuments 
to themselves in the form of large boulders transported by the drift, 
found in their neighborhood, and presenting some strange or unique 


feature. I noticed a large block of the handsome porphyritic gneiss 
VOL. HI. 33 


254 SURFACE GEOLOGY. 


found in the east part of the town, and two boulders of andalusite schist, 
with coarse and fine crystals, one of them apparently from Carr’s moun- 
tain. These specimens ornament the grounds of the institute, while 
other minerals are exhibited under glass. 

In order to give some idea of the distribution of boulders in the state, 
I will select a few examples, and describe carefully the kinds of rock 
found, their size, probable origin, and distance of transportation. In the 
same connection, other interesting features illustrating the general sub- 
ject may be mentioned incidentally. Some generalizations may follow 
the description of localities. 


Boar’s Heap. 


In the middle of Hampton Beach, a mound of drift about 1300 feet 
long and 45 feet high, rises very conspicuously to view. It is the well 
known Great Boar's Head, visited every summer by thousands of people 
for the enjoyment of sea air and bathing. Though small, it may be re- 
garded as a true lenticular moraine, isolated from all visible connection 
with any other mass of till, by a distance of nearly two miles between the 
nearest points. It has been exposed to the wearing action of the sea 
from time immemorial, and consequently has lost a considerable portion 
of its mass. The clayey portion of the till is washed out, leaving the 
stones, and consequently the former size and shape of the mound is 
clearly indicated at low tide by the remnants. From the extreme point 
of the cliff these boulders extend south-east for 400 feet. Their northern 
limit is about a quarter of a mile north of the Boar’s Head hotel; opposite 
the middle of the cliff the boulders are continuous 120 feet to the fucus 
growth, and a single stone projects out of the water as far again. If the 
hill were restored to its original dimensions, it would probably be 1800 
feet in length by 350 in width, with a course about N. 35° W. It was 
steepest on the south side. Mr. S. H. Dumas, the proprietor of the hotel, 
thinks there has been no wearing away of the hill of any consequence 
for many years. The landing-place for boats on the south side has been 
constructed as it is now for the past forty years. If a new one were 
desired, no change of position would be required; so that the erosion 
on that side has been very inconsiderable. The present slight curve in 
the beach north of the hotel he remembers to have been straight once. 


GLACIAL DRIFT. 255 


Mr. Joseph Dow, of Hampton, says a measurement of the bluff in 1875 
showed that a length of one rod at the point had disappeared since 1826; 
and his impression is that a prominent stone, called Gunning Roék, near 
the end of the boulders, is farther removed from the bluff now than it 
was forty years since. 

A view of this bluff from either side near the end shows finely the 
distinction insisted upon in this report between the lower and upper till. 
The sides of the bluff meet 


Upper till. 
at the end, making a sharp on 
edge, which dips towards the 
east at an angle of 60°. Fig. ome 

wer fill. 


54 is copied from a photo- 2 
graph, which shows the line Fig. 54.—SECTION OF Boar’s HEAD. 
between these divisions as plainly as in nature. The upper part has 
been broken away near its end, but its depth is nearly uniform over 
the whole plain, about ten feet, or a little less, at the end. This has its 
usual reddish-yellow in distinction from the bluish cast of the lower till. 
It is ferruginous, comparatively loose in texture, and contains rough 
stones, rarely any that have been striated, and the material is chiefly 
the slates found in place two or three miles distant. Being easily 
crushed, the upper till contains an unusual proportion of earth. Its 
resemblance to the upper till of Portland, Me. is obvious. The lower 
thirty-five feet of till is composed of very compact, gritty earth, slightly 
clayey, containing numerous smoothed and striated boulders, from grains 
of sand to fifteen feet in length. Many of the stones are in the condi- 
tion of unstable equilibrium. The uncovering of the boulders by wash- 
ing enables us to learn their nature, and refer them to their probable 
source. A careful description of the different kinds observed here 
will illustrate the origin and dispersion of all the boulders along the 
sea-shore. The most abundant rock is sienite, boulders 12 and 15 feet 
in length occurring occasionally. Those 6 feet long are common. They 
are all glaciated, but many have been smoothed since falling out of the 
bank by the waves. It is gray with a considerable sprinkling of white. 
I will group the boulders according to size. Of those about six feet in 
length are sienite, gneiss, trap, Pawtuckaway sienite, granite with blue 
feldspar, such as occurs in ledges at Frost’s Point in Rye, crumpled 


2 56 SURFACE GEOLOGY, 


gneiss of the Manchester and Deerfield range. We found the following 
in pieces from three to four feet long: Sienite of Exeter, the most abun- 
dant as usual, and twelve different varieties ; well defined gneiss, flinty 
slate, ferruginous mica schist, porphyritic gneiss (some blocks like that 
of East Concord, others like the New Hampton rock, the feldspar very 
abundant in double crystals), breccia of flint or indurated slates, sienite with 
black patches, dolerite, gneisses like the Laurentian, green augite rock, 
Concord gneiss, porphyritic gneiss with large garnets, saccharoid quartz, 
gabbro like that of Gilford, sienite with feldspar— perhaps labradorite 
and fine gray granite. The following were found of less dimensions than 
three feet, down to pebbles: Montalban schist with blotchy mica, trap of 
various textures, granite like that of Barre, Vt. clay slate, andalusite 
mica slate, jaspery quartz, slates like those of Portland, Me., fine-grained 
reddish whetstone slate, Manchester gneiss, greenish sienite with por- 
phyritic like parallel spots of gray quartzite, argillo-mica schist, reddish 
porphyritic rock or sienite, gray garnet rock, Albany granite, red por- 
phyry, white breciated quartz porphyry, and Tripyramid sienite or dio- 
rite; also, reddish weathering limestone, such as occurs in eastern 
Maine. 

The most conspicuous and abundant of these materials came from the 
sienite range extending between Dover and Exeter, and travelled from 
nine to fifteen miles. A few of this class may have originated in a range 
three miles nearer. Many of the slates came from the ledges inside of 
the sienite. No andalusite slate is known to exist within twenty-five 
miles. The Manchester gneisses have travelled certainly twenty miles ; 
the others may have come from either a greater or a less distance. I know 
of no porphyritic gneisses, like those occurring here, nearer than forty-five 
miles in a north-west direction, while ledges sixty miles distant agree 
with them exactly. The gabbro found at Gilford is in boulders, so that 
I cannot certainly refer to their source. I find nothing that seems to 
have come from a greater distance than the Tripyramid sienite, at 77 
miles. The porphyries may have come from greater or less distances, 
possibly from the Ossipee mountains. Others of the pieces are like 
rocks further north, but I cannot claim anything but the minimum dis- 
tances. I do not specify many other distances that might be mentioned. 

I have assumed the north-west to be the proper direction of dispersion, 


GLACIAL DRIFT. 257 


and nearly all the boulders seem to have come from that direction. The 
schists like those at Portland, Me., cannot be indisputably proved to have 
come from that quarter; but if there were evidence of a south-west cur- 
rent, I should refer to that locality for their origin. The most difficult 
fragment to explain is the piece of limestone about a foot through, found 
at the eastern edge of the cliff. It is drab colored, weathering reddish, 
and tarnishes quickly after exposure. There is nothing like it in New 
Hampshire, nor in western Maine. It is like some limestones from the 
vicinity of Machias, 190 miles distant north-east in an air line, or New 
Brunswick, much farther. I inquired whether ballast from schooners 
might not have been thrown out upon the beach; but those who have 
lived here for many years thought the stone could not have been brought. 
in that way. Our conclusion is, that the stone came from the bank, more 
likely the upper than the lower division, and that its original source was 
towards the north-east. We need, however, confirmatory observations 
before throwing down the gauntlet in favor of this proposition. 


Dover. 


The locality examined is the excavation in the kame half a mile north-- 
west from the post-office, made by the Dover & Winnipiseogee Railroad, 
figured and described upon page 158. The previous example was in till; 
this is in material derived from the modification of the upper till, and the 
stones have travelled somewhat further than to their place of deposit 
from the glacier. The largest stone I have seen in any gravel deposit 
in the state occurs here, weighing sixteen tons. There are others two 
thirds the size of this, all of mica schist, with rough edges, showing only 
a short carriage. It is the rock of the neighborhood, and consequently 
the most abundantly represented among the pebbles. Others are fine- 
grained granites, Montalban schists, Concord granite, trap rocks, White 
Mountain porphyry, red porphyry (like that occurring upon Mt. Lowell), 
Albany granite, Tripyramid diorite, sienite (like that on Red hil), sienite 
with two kinds of feldspar, and the granite of Hart’s Location, such as 
has. been quarried on Sawyer’s river. Probably ten per cent. of these 
stones came from the White Mountains, some of which can be shown to 
have been carried more than sixty-five miles. Perhaps most of them 
might have been derived from the Ossipee group, within forty miles, 


25 8 SURFACE GEOLOGY. 


Supposing the course of the strize about S. 20° E., the Concord granite 
would have come from Farmington, 15 miles distant; the sienite from 
Gunstock, from 25 to 35 miles; the Montalban rocks about the same 
distance, or a little more. 


MANCHESTER. 


The city authorities have made numerous cuttings on various kinds of 
material within their limits, which can afford the most abundant informa- 
tion respecting the different kinds of material present in the drift. I 
searched for rocks transported a great distance rather than for the entire 
variety, so that my list is small. On Wilson’s hill, at Lowell street, exca- 
vations have been made to the depth of from 12 to 15 feet, the finer 
sandy and gravelly portions separated by screens and carted away, leav- 
ing the stones and boulders, none of which exceed two or three feet in 
diameter. The excavation shows several features concerning the nature 
of the till better than anything seen elsewhere, and deserves to be shown 
in photographic illustrations. The examination was made before our 
decision to distinguish between the lower and upper till. The excava- 
tion probably exhibits both kinds of till, the upper a coarse, yellow gravel, 
from two to three feet thick. The surface of the hill is smooth, with 
scarcely any large boulders visible. There is a layer several inches thick 
of a sand overlying the gravel. Roots of pine trees have penetrated the 
earth to the depth of six feet. The lower till here contains many glaci- 
ated stones, including those that have come from the greatest distances. 
The material resembles clay, but, when pulverized between the thumb 
and fingers, is seen to be gritty, composed of siliceous rather than alumi- 
nous particles. This remark is applicable to very much of the drift de- 
posits of southern New Hampshire, and explains our preference for the 
name 72//, adopted in this report for these accumulations, rather than 
boulder clay. The till here presents a laminated appearance, with hori- 
zontal partings, and iron oxide in the seams, evidently derived from water 
soaking down from the soil above. This laminated aspect is very com- 
mon in the lower till, and is believed to result from the enormous pres- 
sure exerted by the presence of the ice-sheet. Two thousand or three 
thousand feet thickness of ice are adequate to induce these cleavage 
planes in the moist and slightly plastic earth. They cannot have come 


GLACIAL DRIFT. 259 


from deposition, as there has been no sorting of the material. Possibly 
some authors have mistaken these lines for stratification. 

An uncommon feature is the presence of cracks and cavities, or what 
seem like such openings, one or two inches wide, filled with the upper 
gravel. Some masses of the lower till are entirely encompassed by 
them, so that in a section they appear like imbedded, irregular patches. 
The till occupies most of the area, the gravel occurring mainly in the 
veins. The section suggests the possibility of ice occupying the present 
position of the veins at first, and the subsequent infiltration of gravel 
after the melting of the frozen material. There are cases on record of 
large fragments of boulder clay transported by ice as if they were rocks, 
There might have been disturbances in the till, and the interspaces sub- 
sequently filled with gravel. This gravel does not show any cleavage 
structure like that of the lower till. 

The larger of the boulders here are of granite, such as occurs within 
two miles. Those next in size are of the Manchester or Hooksett quartz, 
and mica schists of Andover and Franklin. Stones four inches long are 
composed of the Albany granite, and there are also two kinds of White 
Mountain porphyry. Similar White Mountain boulders occur in a rail- 
road cut very near Massabesic lake, in a compact, elongated moraine, 
different from anything else in the vicinity. 

The greatest distance of carriage indicated by these boulders is 68 
miles. The mica schists travelled about 35 miles. The great bulk of 
the stones on Wilson’s hill has come, therefore, from 35 miles and less. 

A pebble of White Mountain porphyry has been shown to me by a 
resident of Nashua, who found it near his home. This must have 
travelled as much as 86 miles. 


Concorp. 


An examination of the Concord kame showed many stones 8 to 10 and 
12 inches in diameter, more than three fourths consisting of the Con- 
cord granite and associated rocks. I found, also, white quartz, ferrugi- 
nous schists, porphyritic gneiss, trap, blue quartzite, hornblende schist, 
gneiss, and a possible example of Huronian schist from the Connecticut 
valley. Careful search failed to discover any rocks from the White 
Mountains. This indicates that the locality is too far west to receive 


260 SURFACE GEOLOGY. 


contributions from the mountains. It suggests the probability of the 
transportation of those at Manchester and Nashua by the local Merri- 
mack glacier. The ice from the White Mountains would meet the tribu- 
tary glaciers from the west, and be compelled to slide upon the east side 
of the valley exclusively. Hence, whatever boulders came from the 
White Mountains would be found upon the East Concord or Manchester 
side of the valley. 

As the continental glacial sheet moved to the south-east, it follows 
that whatever White Mountain blocks are found in the lower till of the 
Merrimack basin must have been transported by a valley movement, un- 
less the natural radial divergence from the mountains could have spread 
as far west as Manchester. 


HANOVER AND VICINITY. 


Passing over to the Connecticut valley, boulders of a different class 
present themselves to view, or those derived from Vermont. We also 
find a large proportion of them brought by the south-east current, 
although the strize close by run west of south. This confirms our pre- 
vious suggestions of the existence of both movements in this valley. 

About two miles north of Dartmouth college the kame furnishes the 
following pebbles, the largest 10 inches in diameter: Barre granite, 
Bethlehem gneiss—both varieties, Huronian diorite, quartz schists with 
decayed layers, calciferous mica schist—several varieties, clay slates, 
hornblende schist, jaspery quartz, quartzite, decayed limestone. Else- 
where this ridge furnishes handsome pieces of red jasper, thought to 
have been derived from ledges west of the Green Mountains, a distance 
of 70 miles. The Barre granite has been carried 32 miles. The Bethle- 
hem gneisses are in place one mile east of this kame for four miles, but 
they more probably came from Haverhill, 40 miles distant, unless trans- 
ported down from the Jacob’s brook glacier in Orford, on the east side of 
the valley. These pieces travelled on the Connecticut glacier. The 
various Huronian and the calciferous schists, and the slates, mostly came 
from the north-west, involving from a few rods to several miles of car- 
riage. 

Further east are heavy deposits of till composed of long travelled and 
much glaciated stones. Three of them are represented in the accompa” 


Missing Page 


GLACIAL DRIFT. 261 


nying heliotype. The two upper figures show the opposite sides of the 
same pebble—nearly of the natural size—of a mica slate, not of remote 
origin. On one side the striz run at a small angle with the longer axis 
of the pebble. On the reverse side the lines are irregularly disposed. 
The lower left-hand view shows an argillaceous schist, derived from 
ledges five or six miles distant, of oblong shape, three inches long, and 
the striae on both sides are approximately parallel to the longer axis. 
The whole surface on every side has been glaciated, some of the depres- 
‘sions being deeper than the others. The other view is of a Huronian 
schist, derivable from ledges three to twenty miles away, 12 inches long, 
7 wide, and 3 thick. The upper end has been partially encrusted with 
carbonate of lime of more recent origin than the striz. The opposite 
flat sides are scratched parallel to each other, and the longer axis of the 
stone. The ends are rough. This represents the shape and peculiarity 
of the striation of a majority of glaciated boulders. 

The following varieties of material have been found in company with 
these heliotyped boulders upon the north side of Mink brook, about a 
mile east of the brick church at Mill Village: Hornblende schist, dia- 
base, blue and gray quartzite, clay slate, serpentine, red quartz, red sand- 
stone, and gneiss. The cliff is 4o feet high, the upper ten feet of upper 
till containing limestone. 

These boulders must have been brought by the south-east current, 
some of them 65 or 70 miles. I think there is a notable absence of the 
Bethlehem gneiss among them. In the north part of the town the drift is 
very thick on the northern slopes. On following Mink brook to its source, 
in the south-east corner of the town, other similar ground-moraines occur. 
The same are more abundant south of Hayes hill in the edge of Leba- 
non. A tributary of the Mascomy has cut through this deposit, produc- 
ing by erosion terraces of till. The surfaces of all these moraines are 
smooth, indicating the sliding of a glacier over them. Between Prospect 
and Corey hills is a smooth depression rising gradually to the curved 
water-shed between the stream flowing west and Mink brook. Scarcely 
any boulders occur on this basin; but after beginning the descent to Mill 
Village, coarse moraines and large rough boulders, twelve and fifteen feet 
through, abound. It would seem that the glacier broke off the fragments 


from the ledges of the smooth area, carried them to the brink of the 
VOL, Ill, 34 


262 SURFACE GEOLOGY. 


declivity, pushed them over, and left them on the lee side of the hill. 
The contrast between the smooth fields south of Prospect hill and the 
rough pastures towards Mill Village is very strongly marked. On the 
hill north-east from Colburn’s, in the edge of Lebanon, is another enor- 
mous accumulation of large gneissic blocks. On the College grounds, to 
the west of Culver hall, the surface was formerly covered by numerous 
large blocks of hornblende schist, sometimes ten feet across, derived 
from the adjacent ledges, and transported southerly by the Connecticut 
glacier. Excavations showed that some of them occupied an unstable 
position; if the earth were removed from their sides, they would topple 
over. It is a characteristic of till, that many of the boulders are so situ- 
ated, and it bears witness to their method of removal. Had they fallen 
from an iceberg, they would rest with the centre of gravity 2 equelibrio. 
Now they are kept in a forced position, such as would result from the 
shoving along of a pile of débris, or such action as arises from the move- 
ment of a glacier. Underneath this clayey coarse drift the material is 
gravelly and less compact, derived from the gneissic rather than the 
slaty rocks of the neighborhood. 

Quechee Railroad Cut. Between Hartford and Quechee villages the 
Woodstock Railroad has cut deeply into the lower till, affording the hand- 
somest exhibition of the two varieties of till yet displayed in this region. 
The cut is 40 feet deep, three fourths of it being the lower member, very 
compact, full of small-sized glaciated stones cemented together by thick 
boulder clay. Every stone is striated. There are great numbers of the 
Burlington red sandstone, and many beautiful green serpentines. The 
most common are of gray quartzite. One was composed of a fossil coral. 
The red stones have travelled the greatest distance, from over the Green 
Mountains, about sixty miles. Concerning these and the similar ones at 
Hanover, it is to be remarked that they were raised over an acclivity of 
3,000 feet altitude as well as transported a great distance. The upper 
ten feet of this cut is a typical locality for the upper till. There is the 
distinctively reddish-brown color, loose consistency, rough blocks com- 
mon with an occasional striated one, and very many of the siliceous lime- 
stones of the neighborhood. None of the latter were observed in the 


lower till. 


GLACIAL DRIFT. 263 


Bou.tprers From Mr. ASCUTNEY. 


If different ice-currents have struck the ledges, and transported frag- 
ments in several directions, we shall expect to find the boulders quite far 
apart at a considerable distance from the source. As an illustration of 
this wide spread of materials starting from a small area, I will mention 
what is known about boulders starting from Mt. Ascutney, as their min- 
eral character is peculiar, and not likely to be mistaken. In Claremont 
they are very abundant, about eight miles and a half distant, and the 
direction south-east. In Surry, on the west side of Thompson brook, in 
the north-west part of the town, Butler’s rock, a boulder 20 feet long, 20 
feet wide, and 12 feet high, came from Ascutney. The distance of trans- 
portation is 27 miles in the course S. 10° E. In Keene—west part—is a 
striated Ascutney boulder five feet in diameter, S. 8° E., and 35 miles 
distant from its source. G. A. Wheelock informs me of the existence of 
similar blocks at the west base of Monadnock, S. 20° E., and 42 miles; 
also one in Mr. Newton’s garden in West Swanzey; 20 in Keene, the 
largest on Samuel Towns’s farm; three in Surry; several in Alstead ; 
very many at Paper Mill; and Dr. Prouty found one in Langdon, two in 
Gilsum, and one in Sullivan. Others are on Mr. Gilbert’s farm in Wal- 
pole, two in Westmoreland, and one at Ashuelot. This last is nearly due 
south, and 45 miles distant. Another is at R. C. Fisher’s in Hinsdale. 
The only other example in mind is in the north-east corner of Bernards- 
ton, a small stone 50 miles distant from Mt. Ascutney, and S. 4° W. in 
direction. 

If lines were drawn from Ascutney to all these points they would cor- 
respond to radii. If the Claremont stones continue south-east, which 
seems likely, any occurring at the south state line in Pelham would be 
85 miles distant, and 36 east of the Bernardston example. In this in- 
stance it is easy to account for the wide spread of the stones by the 
south-east current for some, and the Connecticut valley movement for 
the others. It is a question worthy of investigation, whether all boulders 
have a radial dispersion like these from Ascutney. The facts of this 
dispersion ought to be gathered in greater abundance, and compared 
with those obtained elsewhere. 


264. SURFACE GEOLOGY. 


BouLpERLESS AREAS. 


In New Hampshire no considerable regions are devoid of boulders, 
except areas of sand where the stones are concealed by deposits of later 
‘age. The nearest approach to a boulderless area is in the limestone 
regions of Cornish and Colebrook. In eastern Vermont the absence of 
boulders over the same formation is very conspicuous, as may be seen 
in passing up Wait’s river and the east branch of White river. The 
boulders of the underlying rock decompose readily, and it is believed 
that though once as common as the average of granite blocks in New 
Hampshire, they have been disintegrated by atmospheric agencies, leav- 
ing very few signs of glacial work. Occasionally lines of granite boul- 
ders occur in this calciferous area, enough to show that the glacier did 
not slight it. Such boulders would furnish excellent studies of the radial 
dispersion of fragments, as their distribution could be easily made out. 

On the contrary, some kinds of rock seem almost incapable of decom- 
position, and leave the fields profusely strewn with them, The porphy- 
ritic gneiss and the Exeter sienite areas are remarkable for the great 
amount of rough blocks of their own kind scattered over them. They 
are mostly those that have just started on their travels. Between Dover 
and Exeter the loose fragments of sienite scattered over the area occu- 
pied by this rock are numberless, and commence abruptly on the north- 
west side. One knows that he has reached the sienite rock by the 
numerous blocks of it seen long before a ledge can be found, it may be. 
I suppose their abundance is to be explained by their difficult decompo- 
sition. 


LarGE BouLDERS. 


Although our state is noted for the great abundance of boulders 
strewn over its surface, it is only quite recently that I have seen boul- 
ders in our limits larger than any of which mention has been made in 
the writings of American geologists. They were brought to our notice 
by His Excellency Governor Prescott. Regret had been expressed to 
him that no boulder had been found in the state equal in size to those 
known to exist in the neighboring states. As if he felt the credit of the 
state impaired by the imputation, he immediately searched the neighbor- 


GLACIAL DRIFT. 265 


hood of Pawtuckaway mountain, and found a very formidable array of 
giant fragments superior to anything else described elsewhere. The 
celebrated Pierre-a-bot of the Jura contains about 40,000 cubic feet, 
weighing 3,000 tons; the Green Mountain Giant of Whitingham, Ver- 
mont, has the same cubical contents; the one formerly existing at Fall 
River, Mass., now destroyed, is estimated to have weighed 5,400 tons. 
The Churchill rock of Nottingham, shown in a heliotype at the begin- 
ning of this chapter, measures 62 feet long by 40 wide, and is estimated 
at 40 feet high. Making liberal allowances for irregularities in its 
dimensions, it contains over 75,000 cubic feet, weighs 6,000 tons, and 
is therefore nearly double the size of the Jurassic and Vermont exam- 
ples. Bingham’s rock at Smuggler’s notch in Vermont is larger, but is 
so connected with a ledge as not to be properly esteemed an erratic. 
The Swiss example has been transported much farther than either of 
the New England boulders. 

Churchill rock is on the south side of north Pawtuckaway. It lies in 
a valley not shown on our map by contours, starting at the middle of the 
Deerfield and Nottingham line where it passes over this peak, and point- 
ing east to Round pond, made a part of Pawtuckaway pond upon the 
county map. This valley is half a mile long, and displays a very remark- 
able lot of large boulders and moraines. The commencement of the 
valley is a narrow notch in the sienite of the mountain, full 200 feet deep 
and narrow. The boulders seem to have been detached from the cliffs on 
either side of the notch, and then transported by the ice, perhaps, or local 
glacier, eastwardly. Within a few rods of the starting-point are several 
large blocks, worthy of special measurement anywhere except in their 
company. About an eighth of a mile down, too far to allow of their 
accumulation by gravity, are six large boulders close together, each one 
averaging 30,000-35,000 cubic feet. A little beyond them is Chase 
rock, 40 feet long, 40 feet high, and 30 feet wide. About a quarter of a 
mile or a little less from the starting-point is Churchill rock, and close 
by it two others, one estimated as equal to 30 feet in each direction,— 
27,000 cubic feet,—and the other ten feet longer, with the same breadth 
and height, or 36,000 cubit feet. On climbing the mountain north of 
Churchill rock, some large blocks are seen, which have been severed 
from connection with the ledge; one of them 50 feet long, slab-like in 


266 SURFACE GEOLOGY, 


form, rests slanting against the hill-side, so as to make a natural shed for 
the cattle. 

Churchill rock received its name sixty years since, from the circum- 
stance that a lunatic of that name escaped from his keepers, and was 
discovered on top of this boulder. It will be seen that the rock is 
divided by a crevice, originally a joint, providing a space usually a few 
inches in width. Mr. Churchill must have crawled up through this nar- 
row opening, doing, like other persons in his condition, what seems 
almost impossible. It was found necessary to fell a tree upon the rock 
to insure for the man a safe descent. The base of the stone is below 
the feet of Gov. Prescott, as represented in the heliotype, who stands 
the lowest down of the four persons seen in front. The top is midway 
of a pine tree with a trunk nearly two feet in diameter, and was thought, 
by some on the ground, to be 80 feet high. ; 

Chase rock is well shown in another heliotype, with a profile view upon 
its summit of Erastus H. Chase, the proprietor of all these large boul- 
ders. Fifty years had elapsed since he climbed the boulder before. He 
took great enjoyment when a lad in climbing this rock. It is much more 
narrow when viewed from either end. 

On passing nearly to Round pond, almost three quarters of a mile 
from the Pawtuckaway notch, we reach Ballad rock, so named from a 
preacher who used one of the projections for a pulpit in the early history 
of the town. A heliotype sketch of this is presented, showing two or 
three of the constituent boulders of this moraine, for it is a terminal pile 
of rubbish. It may have collected behind a ledge, though it is not always 
easy to separate ledges from boulders in this vicinity. The largest stone 
is 60 feet long and 40 feet wide, and ovoid in shape. The moraine itself 
is 150 feet wide and over 100 feet high. Five or six of the large boul- 
ders in it are readily discernible to the visitor. The view is somewhat 
defective, because of the difficulty of obtaining a good light in the forest 
late in the afternoon. This moraine is really more remarkable than the 
single large boulders, because it is composed of several pieces, each as 
large as Chase, if not Churchill rock. The ridge extends to the pond, 
and its base is crossed by the road. 

We find, therefore, in this short distance of three quarters of a mile, 
certainly a dozen boulders, each exceeding 25,000 cubic feet in dimen- 


GLACIAL DRIFT. 267 


sions. Their position requires the invocation of glacial action to ac- 
count for their removal from the pinnacle or cliff from which they seem 
to have come. We could not have expected anything less than such a 
royal discovery, when the chief executive of the commonwealth set him- 
self to search for something worthy of mention. 

Vessel Rock. In Gilsum a large boulder (Fig. 55), called Vessel Rock, 
from its fancied resemblance to a ship, has long attracted attention. Dr. 


pad gig ee 
cae a ‘Ee > 


ee Deed 


Fig. 55.—VESSEL Rock, GILsum. 


Jackson described it in his report, and thinks it came from a coarse gran- 
ite ledge fifteen rods distant, according to G. A. Wheelock. The rock 
itself measures 46 feet in length, 24 wide, and 26 high, containing over 
28,000 cubic feet. A piece was split from it by frost in 1817, measuring 
33 feet long and 10 wide. The whole stone before splitting was said by 
Jackson to include 32,000 cubic feet, and to weigh 2,286 tons. Other 
large fragments of the same rock occur to the west and south. The 
building shown in the figure is a school-house. It is about a mile and a 
half south-west from the village. 

Elephant Rock. This boulder is situated in Newport, within a few 
feet of the summit of Pike hill, fully 1,500 feet above the level of the 
sea. It is composed of graphic granite. Its length is about 29 feet, 
and its height not far from 23 feet. The rock is represented in F ig. 56. 

Dr. Jackson says, in his report (p. 100)—“Some immense blocks of 
granite occur in Northumberland, on the estate of Mr. Mills Olcott, of 


268 SURFACE GEOLOGY. 


Hanover. One of them has the following dimensions: 30 feet long, 18 
feet high, 27 feet wide, and contains 4,580 cubic feet. The other is 32 
feet long, 6 feet high, 9 feet wide, and contains 1,152 cubic feet. Itisa 
light-colored granite, of excellent quality for building. These blocks of 


Fig. 56.—ELEPHANT Rock, NEWport. 


granite are different from any rocks found in place in the immediate 
vicinity. The nearest granite ledge is one mile north of it, but is of a 
different kind. The original bed must be some distance to the north- 
ward.” 

Conway Boulders. Prof. E. J. Houston describes a large boulder, near 
the house of E. S. Stokes, North Conway, in much detail in the Fournal 
of the Franklin Institute, Volume LXII, 1871. He calls it the Pequaw- 
ket boulder. It is of coarse granite, with a preponderance of feldspar, 
considerable quartz, and very little mica. The general form is that of a 
parallelopiped, one of whose longer sides is partly buried. The length 
is 52 feet 6 inches; greatest breadth, 21 feet; greatest height, 33 feet 2 
inches; and it is estimated to weigh 2,300 tons. Several large fragments 
surround the mass, seemingly once connected with it. One is 31 feet 3 
inches long, 15 broad, and 21 high. On the south-east side is another 
piece 31 feet 7 inches long, 15 feet 3 inches broad, and 11 feet 7 inches 
high. Several spruces and beeches conceal the boulder from the road. 


GLACIAL DRIFT. 269 


A moraine runs up the hill, N. 80° E. from the boulder, containing many 
large blocks. About 600 or 800 feet higher they average 12 by 13 by 
15 feet. A few hundred feet below the Pequawket is another mass 31 
by 18 by 21 feet. 

There is another one called the Washington Boulder, represented in a 
heliotype. It is about a mile north-east from Conway centre, near Pine 
hill. Its dimensions may be expressed by about 30 feet high, 40 long, 
and 25 high. It is one of the notable objects of Conway, and is com- 
posed of the granite for which the town is famous. It cannot be shown 
to have travelled far. . 

Bartlett Boulder. This is not so noted for its size as position. It has 
the typical shape of glaciated stones,—15 feet long, 12 feet wide, 10 feet 
high,—and rests upon four smaller blocks. The entire assemblage rests 
on stratified sand: hence it was moved to its present position at the time 
of the melting of the ice. It is represented in a heliotype. 

Ordination Rock, This is in Tamworth, west of the centre village, 
and has a flat top, reached by artificial steps, and is surmounted by a 
monument. It is 30 feet long, 30 feet wide, 12 high, and composed of 
Conway granite. It came from the north or north-east. 

Flume Boulder. The photograph of the boulder suspended over the 
Lincoln flume, Volume 2, page 157, illustrates far better than words how 
this fragment happened to be caught, and now serves the useful purpose 
of keeping the walls of the chasm apart, and of affording amusement to 
thousands of summer visitors. No further description is needed above 
that already given. 

Waterville. Several large boulders must be added to the list of 
attractions for this locality. Near Greeley’s are some 8 feet high, of 
the celebrated ossipyte. Near Mad river are large granite blocks. The 
largest is just above the mouth of Greeley’s Branch, or at the Swasey- 
town falls, 43 feet long, 25 wide, and 20 high. One lower down is 33 
feet long, 27 wide, and 25 high. They are of Conway granite. 


OTHER Larce BoutpeErs. 


On crossing from Moultonville, in Ossipee, to the sources of Lovell’s river, we ob- 
serve a fragment of Conway granite near the height of land, 30 feet long, 27 feet wide, 
18 feet high at the south end, and ro feet high at the northend. There are no ledges 

VOL. IIT. 35 


270 SURFACE GEOLOGY. 


near by, so that it has very likely been brought here from the valley north, and trans- 
ported up hill, 200 feet of vertical height. 

In Hanover, upon the west flank of Moose mountain, east of E. Wright’s, is a boul- 
der of hornblende schist 22 feet long, 12 wide, 16 high, from which a considerable 
piece has been separated by frost. It may have travelled less than a mile. A boulder 
of Vermont granite, perhaps half the size of the foregoing, is said to have been taken 
from the top of Moose mountain and made into monuments for the cemetery. On 
Gen. Jackman’s farm in Bath, there was, a few years since, a line of large Huronian 
boulders averaging 12 feet through, arranged like a lateral moraine. The first cucum- 
bers seen in Bath were raised upon the top of one of them. Near Jones pond in Ray- 
mond is a boulder of twisted gneiss 30 feet long, 25 feet wide, 22 feet high at one end, 
tapering to 8 at the other. In this neighborhood, Raymond, Epping, Nottingham, 


AW 


SN 
S 


Fig. 57.—GREAT Rock IN WENTWORTH. 


similar large boulders are frequent. Those derived from Pawtuckaway are quite no- 
ticeable for twenty miles to the south-east. Several large ones are located upon Gov- 
ernor Prescott’s farm. South of the station at Raymond is a boulder of white quartz, 
transported several hundred feet, 48 feet long, 39 wide, 24 high (30 feet at one end), 
with two pine trees on top, one 16 inches in diameter near the base. This compares 
favorably in size with some of the Nottingham examples. Near Brackett’s station in 
Stratham are two sienite boulders, each averaging twenty feet in three directions, that 
have come two or three miles. Near Bronson’s house in Landaff are boulders of 
conglomerate 30 feet in each of the three dimensions. They probably came from 
some undiscovered layer not far distant. 


GLACIAL DRIFT. 271 


Fig. 57 represents Great Rock in Wentworth, with Mt. Carr in the distance. Two 
persons seated upon the summit illustrate the size of the boulder. 

In the west part of Fremont are a great many boulders, each from 12 to 15 feet long. 
The same is true of many other portions of Rockingham county, as near Windham 
junction, on Clyde hill, where mention is made of one weighing 500 tons. 


RockING-STONES. 


‘When large boulders are left on ledges they may be so evenly bal- 
anced that a slight effort only is needed to make them oscillate. Such 
cases as have fallen under my notice are the following : 

On Shirley hill, Goffstown, just east of Uncanoonuc, there are two. 
One of them is 8 feet high and 42 feet in circumference. The dimen- 
sions of the other are not stated. With them is a third large stone. 

Governor Prescott speaks of a rocking-stone upon Mt. Pawtuckaway. 
Seneca A. Ladd, of Meredith village, informs me of the existence near 
his residence of a small rocking-stone. 

Up Corey hill in Hanover, half a mile east of Dartmouth college, is 
a rocking-stone 12 feet long, 10 feet wide, 54 thick, containing about 480 
cubic feet. Its of Bethlehem gneiss, and has been transported only a 
short distance. 

On a high hill, about a mile west of Newport village, is a rocking-stone 
weighing not far from 25 tons. It is about 9 feet high, egg-shaped, and 
stands upon its larger end. 

Upon Russell Clifford brook in Warren there is said to be another, of 
these stones, with a tree growing on the top. 

Boulders on top of high mountains. Those on Mt. Washington have 
been mentioned; see page 208. On top of Dixville mountain is a boul- 
der of hornblende rock 5 feet long. Has travelled several miles. Can- 
non mountain shows a porphyritic gneiss block 4 feet in all directions, 
which may have come from Bald mountain, about two miles distant, and 
been elevated 1650 feet. Mt. Kearsarge exhibits a great many boulders 
of the same material, 5 feet long, that have been elevated more than 
those on Cannon. Granite boulders are common on the top of Moosi- 
lauke; also, Bethlehem gneiss, Lisbon Huronian, Montalban mica schist, 
Cos quartzites, besides the common rocks of the mountain. Of these, 
the Montalban may have come from the north, Essex county, Vt., forty 
miles away; the Huronian not necessarily more than twelve miles; 


272 SURFACE GEOLOGY. 


the quartzites a less distance. The origin of the Bethlehem gneiss is 
not clear ;—if from west of north, it may have come from the north part 
of Haverhill, very near. If the current west of south brought any ma- 
terial to the summit, the boulders would naturally have come from Beth- 
lehem, less than twenty miles away. Upon Mt. Lafayette are many 
boulders of the darker variety of Bethlehem gneiss, derivable either from 
the east or west of north. A fine-grained granite, Huronian hornblende, 
and gneiss occur about fifty rods below the top. Forty feet below the 
top, on the south side, is a boulder of porphyritic gneiss. None of them 
are necessarily great travellers, say twelve or fifteen miles from the 
north or north-west. The Sugar Hill staurolite is found at the Eagle 
lakes, indicating six miles travel to the south-east. This is different 
from the strize on the mountain, which runs west of south. Both forces 
must have operated here. At the first tank on the Mt. Washington Rail- 
way, say 3,000 feet altitude, are stones of Essex county, Vt., pargasite 
and delicate staurolite; at least, no other localities of these minerals are 
known, a distance of twenty-eight miles north-west. At the third tank, 
5,800 feet, are pebbles of Lancaster or Huronian rocks, that have come 
nearly twenty miles. Near the top of Mt. Madison are handsome gran- 
ite boulders, of such material as occurs a few miles northerly. On Red 
hill, Moultonborough, are fine-grained granite, probably from Waterville, 
black mica schist like that of the Cods group, trap, hornblende, Montal- 
ban and Lake gneisses, all in place near by, except the second, which is 
unknown short of forty-five miles to the north-west. Mt. Mote shows 
slate from the upper Saco valley. From Mt. Chocorua I obtained a spark- 
ling mica schist, which may have come either from the north-west or 
the north-east. Lovell’s mountain in Washington shows mica schist and 
gneiss boulders, which cannot be definitely located. On top of Mt. Ascut- 
ney are argillaceous schist and Huronian diorite pebbles, the first from 
the north, the second probably, not necessarily, from the same quarter. 

On the top of the north Twin mountain are boulders of Bethlehem 
gneiss from the north-west, ten to fifteen miles. The slide on the north 
side has many Huronian fragments, that have come about twenty miles. 
Cherry mountain summit shows Bethlehem gneisses from Jefferson, the 
next town. There are boulders of porphyritic gneiss on top of Mt. 
Gunstock. 


GLACIAL DRIFT. 273 


MiscELLANEOUS ITEMS. 


A few other facts concerning the dispersion of drift and other glacial 
phenomena are worthy of preservation, although it is not possible to 
state them systematically. I have placed several hundred specimens 
of boulders found in various parts of the state in the Hanover museum, 
properly catalogued, so that it may be consulted by those who wish to 
verify the statements of this report, or obtain hints of facts not alluded 
to in it. Many of the specimens represented strange information at 
the time of the collection, not now valuable except as illustrating the 
fact of dispersion. Others are from noted boulders, or collected upon 
the tops of mountains, or represent the supposed underlying rock in 
the absence of ledges. 


On the west slope of Gardner’s mountain, near Hunt’s, are boulders of the Craftsbury 
concretionary granite (petrified butternuts), with ordinary granite and hornblende rock 
from Vermont. , 

In West Littleton are two houses (Wheeler), and others in Lancaster, built of the 
Vermont granite brought to New Hampshire by glaciers. 

Mt. Carmel in Pittsburg, as seen from Dixville mountain and Mt. Washington, pre- 
sents a good example of a large eminence rounded on the north-west by the ice striking 
it, and rough on the lee side where the force of the ice had abated. 

Between North Lisbon and Streeter pond a mass of till more than 100 feet thick has 
been cut through by the south branch of the Ammonoosuc, and fine sections are ex- 
posed upon it. Ledges are scarce near the river. 

Rocks full of segregated veins weather unequally, often affording curious shapes. It 
is quite common to see these stones placed in conspicuous positions upon walls or in 
dooryards by the farmers, who take pride in their exhibition. The siliceous limestone 
of the mica schist, the finer-grained sienites, and the segregated veined variety of 
(Lake) gneiss afford the best examples of this erosion. I recall examples in Bath 
and Center Harbor, resembling piano-stools and mushrooms. 

The importance of soapstone has led to noting the position of boulders of it in cer- 
tain parts of the state. Those in Pelham, Keene, and at Island pond in Hampstead, 
have not been referred to their source. The original bed is yet to be discovered. In 
New Boston, by the school-house west of S. Dodge’s, are several large boulders, dis- 
tant about four miles in the direction S. 20° E. from the bed on Mt. Misery, Weare, 
their probable source. The same occur in Weare, at the south foot of Mt. Misery. 

Serpentine boulders are common but not abundant in Keene. One in Walpole 
weighs about 350 pounds. 

The numerous gneissic boulders in West Epping led to the discovery of a small area 
of this formation in the Lamprey river. 


274 SURFACE GEOLOGY. 


There is an enormous quantity of porphyritic gneiss boulders about the village of 
Northfield, Mass. Until otherwise proved, they may be supposed to have been trans- 
ported from the area of this ancient gneiss in Winchester by the Connecticut valley 
glacier. It is also interesting to note the derivation of the Triassic conglomerate. The 
largest constituent is an oval-shaped piece of granite. Several are two feet long; the 
rest are smaller. Twenty-nine specimens represent these pebbles in the museum. They 
all came originally from the formations to the north-east and north,—none from the 
west side of the Connecticut. The most abundant are the Montalban schists and gran- 
ites. Others are the Vernon gneiss, hornblende schist, Cods schists and granites, and 
several varieties of quartz from veins. 

Boulders of sienite occur at Freedom village, whose origin is unknown. Ona high 
hill in Eaton are boulders of black quartz porphyry, probably from Albany, twelve miles 
north-west. At the east line of Madison are samples of Albany granite and fine-grained 
sienite from the same region. At the outlet of Newichwannock lake are black porphy- 
ries from the Ossipee mountains to the west, presumably. 

In Center Harbor, between Squam and Winnipiseogee lakes, also further south, are 
many large pebbles of Huronian and Cods rocks. Assuming them to have come down 
Baker's river, they have travelled 40 miles. With them are pieces of the Calciferous 
mica schist limestone, seen also on Mark’s island and in Grafton. These two travelled 
at least 50 miles. 

At the sea-shore on Cape Elizabeth river are numerous glaciated pebbles of a por- 
phyry like that of Mt. Pleasant in Bridgeton, or Burnt Meadow mountain in Brown- 
field, about 40 miles north-west. 

At Littleton, west of the village and near Echo lake, Franconia, are pebbles of anda- 
lusite mica slate, with acicular crystals, like a rock in Granby and Victory, Vt. The 
course would have been only a few degrees east of south. 

Handsome porphyritic gneiss occurs on the east line of Effingham. Its source is not 
clear, whether from the small Albany and Chocorua range, or from the north-east in 
Maine. The same rock in Haverhill probably travelled west of south from the Wing 
Road neighborhood. 

A piece of clay slate in Lyndeborough, if from the north-west, travelled 42 miles. 
Mr. O. E. Randall has shown me pebbles of red sandstones, like that of the Potsdam 
west of the Green Mountains, picked up in Chesterfield. These are like those men- 
tioned as occurring commonly about Hanover, page 260,—the distance probably 
greater—75 or 80 miles. 

About two miles up Imp brook in Bean’s Purchase, almost under the very counte- 
nance of the Imp, are loose blocks 50 to 60 feet long. Between Mts. Pleasant and 
Franklin are many granitic boulders, brought up from the Ammonoosuc valley beneath, 
Io feet square. Jasper pebbles are common about Connecticut Jake and Stewartstown. 
They probably came from Canada. The same occur upon Mormon hill in the north- 
east corner of Lyman. There is in the lower part of Hinsdale village a boulder about 
as large as an old-fashioned school-house, of which the traveller will see many in the 


GLACIAL DRIFT. 275 


hill towns. There is a multitude of large boulders in Franconia opposite the Valley 
house. They cover acres of land, some of them being 20 feet long. On top of Flume 
mountain is a boulder 25 feet long, 15 wide, and 12 high. Near Fifield’s house in 
Thornton, on the east side of the Pemigewasset, is a boulder averaging 30 feet in each 
of the three dimensions. At the south part of Rattlesnake hill, Concord, is an uncom- 
mon amount of boulders of granite, whose dispersion must have been due to the ice. 
Near Gilmanton Iron Works, I found boulders of quartzite precisely like that of the 
Cots group from Moose mountain, Hanover, to Cuba, etc., 6 by 3 by 3 feet. The dis- 
tance from here to the Cuba range, north-west, is nearly 50 miles. We have preserved 
samples of glaciated stones taken from the drift overlying the inter-glacial clay at the 
Weirs and in New Hampton. A block at Weirs is 6 feet square. On the Isles of 
Shoals are boulders that have come from the main land. On the south part of Cho- 
corua are granite boulders 4 feet long, and bits of porphyritic gneiss 18 inches across. 
On the west side of Kimball hill, in the edge of Whitefield, are boulders like the Beth- 
lehem gneiss, perhaps brought there by the glacier described by Agassiz. There is 
also a moraine of the Ammonoosuc glacier, not mentioned above, below Bethlehem 
Hollow. In North Lisbon are bits of Albany granite, 5 inches in diameter, brought 
down by the glacier. 

In Brookfield are numerous boulders of a siliceous limestone, such as crop out ina 
single ledge in Wakefield, and abundantly in Newfield, Maine. These boulders are 
very numerous in Newfield, and they occur on Copp’s Hill, Wakefield. Observations 
do not demonstrate the absence of ledges of this limestone in our state, but the ques- 
tion is raised whether these blocks have not been transported in a south-west direction. 
There is a probability that, when studied carefully, a south-west distribution of boulders 
will be indicated for Oxford and Carroll counties. 


Boulders in Sand. The Portland & Ogdensburg Railway has made 
considerable excavation in the surface deposits between the Notch and 
Fabyan’s, which illustrates the nature of the till and modified drift. At 
the Crawford house is the first excavation, 1,320 feet long and 20 feet 
deep at the middle, made through one of the river moraines described 
on a previous page. The material came down Cascade brook from the 
west., It is entirely stratified, though the materials are coarse, as is 
shown in our heliotype illustration of it. The swell of land crowned by 
the Crawford house is made by this gravel deposit meeting the till of the 
east side of the valley. 

After proceeding 864 feet beyond the gravel cut, there are excavations, 
mostly on the upper side of the track in an ice drift, extending for 408 
feet, where the nearest point to the Saw-mill pond is reached; then there 
is another small cut through the same material for 216 feet. After this 


276 SURFACE GEOLOGY. 


is a fill of 120 feet. Then follows the cut figured in our heliotype, with 
the title /ce-drift over sand printed on a railroad tie. It is a compact, 
unstratified mass of rubbish, the stones consisting mainly of the Mont- 
alban granites and schists common in the neighborhood, overlying layers 
of sand, as shown in the illustration. The material appears to conform 
to the surface of the ground, being just as thick in the depression as over 
the elevations. This earth is evidently some form of ice accumulation; 
it is not water-worn gravel, nor does it correspond to either of the tills. 
It approaches nearer to the coarse gravel at the Crawford house than to 
any other class of deposits known in the state, but is unlike that, in the 
common absence of stratification and the angularity of the fragments. 
Its association with the sand about to be described may intimate the 
presence of a mass of ice in the neighborhood in the time of local gla- 
ciation. 

The rest of the cut just entered into extends for 336 feet. It is com- 
posed of sand, with some large stones in it, underlying the angular drift, 
as seen in the illustration. The strata dip southerly underneath the ice 
drift, and at the north end of the cut they dip northerly to correspond 
with the depression of the surface, 120 feet wide, crossed by the railroad 
upon an embankment. Next is another cut in the sand 264 feet long, 
showing boulders in it, and depressions to correspond with the surface 
of the ground. After an embankment 528 feet Jong, succeeds another 
cut in the sand of 384 feet length. From a point in this excavation, 
about 4,300 feet north of the Crawford station, was taken the heliotype 
illustration entitled Boulder in sand. The fragment may be six feet 
through, composed of bright granite as fresh as if uncovered yesterday, 
and of the same character with the adjacent ledges. Horizontal strata 
of sand underlie it, while the layers are slightly irregular about it, as 
would naturally result from the varying velocity of the current striking 
against the stone. The layers above are regular, and conformable with 
those beneath. This is therefore a clear case of a mass of stone too large 
to have been pushed by the current of water, nevertheless brought to 
this spot by some agent and dropped as readily as if it were a grain of 
sand. There must have been water deep enough to float ice carrying 
this stone upon it; and owing to a change in the equilibrium of the berg 
at this point, the granite fell to the bottom, and lies in a condition of 


GLACIAL DRIFT. 277 


repose, not unstable like the rocks in the lower till. There may be 
twenty other examples of large stones of similar origin in the 1,200 feet 
of excavation passed through north of the ice drift mentioned. The con- 
ditions involved by the facts seem to be the presence of thick masses of 
ice upon the sides of Mt. Tom sliding down like glaciers, and carrying 
detritus, together with the existence of very much water,—possibly a 
glacial lake almost as high as the Crawford house,—into which the bergs 
loaded with stone floated, after being dissevered from their source, and 
dropped their burdens. The waters continuing to flow, layers of sand 
and other débris covered up the dropped fragments until the supply 
ceased. As these deposits are situated upon the surface of the ground, 
they belong to the close of the ice period, and must have been formed 
by local glaciation. If the railroad be followed to Fabyan’s, three or four 
miles further, there will be seen a constant repetition of phenomena sim- 
ilar to those just described. The same is true of the excavations in the 
White Mountains Railroad below the White Mountain house, and be- 
tween Fabyan’s and Ammonoosuc. A cut through “Winding hill,” near 
the “Base” on the latter route, shows coarse boulders, probably glaciated 
at the bottom, capped by stratified layers somewhat ferruginous, suggest- 
ing the lower and upper tills of other parts of the state. 

The sand deposits east of Fabyan’s have large stones resting upon 
them, obviously brought there at the same time and in a similar manner 
with those just described. The valley of the South Branch also exhibits 
fine examples of kames, which seem to have been contemporaneous with 
the sand, and produced by the same glacial currents. 

Other examples of boulders lying in or upon sand have been mentioned, 
upon pages 89, 105, 107, 117, 162-163, etc. Notable instances are also 
just below the Glen house, the Bartlett boulder, at North Lisbon on the 
new Franconia road, and east of Rock Rimmon in Manchester. 


SHAPES oF GLACIATED BOULDERS. 


By far the most common shape of glaciated boulders is that of a 
rounded trapezoidal prism, whose longer sides do not vary much from 
parallelism to each other. One such is figured in the heliotype showing 
boulders from Hanover. In this the ends are rather sharper than is 


common. Perhaps half the thoroughly glaciated stones have such a 
VOL. III. 36 


278 SURFACE GEOLOGY. 


shape. Of these the four longer sides are usually striated parallel to 
each other. 

My attention was called to this as a typical shape by examination of 
certain large striated boulders. In 1856, a boulder of red sandstone was 
exhumed in Amherst, Mass., 6¢ feet long, 54 broad, 2% thick, having 
striz upon the four longer sides parallel to each other.* This was de- 
scribed as something unusual. I found in Quebec, a few years later, 
similarly striated boulders somewhat larger; and in the glacier de 
Bossons in Chamouni, at the foot of Mt. Blanc, I noticed the same trape- 
zoidal figures in a very large stone, 40 by 27 by 12 feet in its dimensions. 
It was striated on the same four sides as the others, and had the ends 
rough. It lay just below the ice, with its longer axis parallel to the 
course of the glacier. Since that time I have always observed the shape 
of glaciated stones, and think the majority have the same form with 
these that I have mentioned. Originally rough, and possibly somewhat 
rectangular, they have been both ground down and striated by the slid- 
ing over them of the glacial rasp, or have been themselves fastened into 
the foot of the ice, and ground over other stones and rocks. After miles 
of scouring, the largest boulders might be worn symmetrically to the size 
of pebbles. On scrutinizing the shapes of stones in the till, one can fre- 
quently find various stages of this process preserved. In Derry and 
Salem I noticed a large number 
of flat stones, of which only one 
side had been smoothed. Let the 
circumstances be changed so that 
these boulders be turned over, and 
.the present upper rough side will 

Fig. 58.—GLACIATED STONE, Moutton- be glaciated, and the whole be- 

amet come symmetrical. A few have 

several faces upon them, as if they had been fastened in the paste several 

times. Fig. 58 shows a glaciated stone in Moultonborough, striated in 

the usual way, and also by a second set (0) across the preceding. It is 

30 inches long, 14 thick, composed of trap, and lies by the roadside upon 
a mass of till. 

A more interesting case has been partially preserved in the Hanover 


* American Fournal of Science, ii, vol. xxii, p. 397. 


GLACIAL DRIFT. 279 


museum. About two miles north of Norwich village, Vt., on the road to 
Copperas hill, is a hill thirty feet high, of lower till with innumerable 
glaciated stones cemented by boulder clay. One of a micaceous argillite 
may weigh 1500 pounds, perhaps five feet in length, of the typical trap- 
ezoidal shape, except it is narrower than usual. The longer axis points a 
little east of south, as the stone lies in the bank. The under surface and 
the sides are striated parallel to the longer axis, but the upper surface 
bears very plain marks at right angles to those beneath. I was able to 
preserve only a piece of this boulder, showing the upper surface and the 
beginning of the lower striz at right angles to them. The boulder 
proved larger than was expected, so that I could not transport it entire 
to Culver Hall. 

A common variation in shape is the elongated narrow one, a prolate 
spheroid. Geikie, in his work on the Great Ice Age, figures four striated 
stones from Scotland, three of which clearly possess the typical shape I 
have mentioned, while the fourth is blunt at one end and pointed at the 
other,—a form also seen with us. These stones show the same features 
the world over. Argillaceous boulders best preserve the glaciation. 


SurFracE Deposits AT PorRTLAND, ME. 


The relations of the two varieties of till to the Champlain gravels are 
not exhibited in any outcrops yet discovered in New Hampshire. A 
familiarity of long standing with the fossiliferous clays and the drift of 


Fig. 59.—SECTION IN TILL, PORTLAND. 
a. Upper till; b. Fossiliferous Champlain beds; c. Lower till. 


Portland, Me., led me to think the question of relative position well 
shown there; and upon examination I discovered that the fossiliferous 
beds occupied a place midway between the two kinds of till. Numerous 
excavations have made the sections in the till and sands perfectly satis- 


280 SURFACE GEOLOGY. 


factory, so that the mutual relations of the three deposits, as displayed 
in Fig. 59, may be regarded as fixed beyond controversy. The massive 
beds overlie the lower till, and are covered by the upper till. These 
facts indicate the deposition, first, of the ferrous glaciated till; second, 
its submergence to at least 100 feet below the present level; third, the 
reddvance of the ice-sheet so as to cover the Champlain beds; fourth, 
the melting of the ice, and the falling down of the débris held in suspen- 
sion in it. The formation of the upper till does not necessitate a sub- 
mergence, as I have insisted in previous publications. That these posi- 
tions may seem well sustained, I will state the most important facts 
observed about Portland. 

The city is situated upon a promontory, or, practically, an island, with 
a north-east trend parallel to the coast. The island has two elevations, 
150 and 160 feet above tide water, and at the remoter ends the extreme 
edges slope very sharply to the water's edge. The eastern elevation is 
Munjoy’s, and the western Bramhall hill, and between the land sinks to 
60 feet along the lowest ridge. These two hills consist of the two kinds 
of till; and each is environed by the Champlain deposits, which cover 
most of the lower area in the middle. These attain an elevation of about 
100 feet; and the ocean must have stood a few feet higher, unless the 
character of the fossils in the lower clays—pelagic forms—necessitated 
a submergence of 300 feet. In that case, Munjoy’s and Bramhall hills 
would have been deeply buried by the waters. 

Munjoy’s hill has been excavated in a multitude of places, showing an 
upper till, from 3 to 10 feet thick, as clearly defined and distinct from the 
lower deposit as at Boar's Head. Boulders from 3 to 4 feet in diameter 
occur upon the surface, and are of the gneissic, granitic, and schistose 
rocks common from four to ten miles to the north-west. Fig. 59 repre- 
sents a cutting between North and Washington streets, and may be 
taken as a sample of excavations on that side of the ridge. Along North 
street for half a mile is a continuous exposure of the two kinds of till. 
Upon both sides is a cut 25 feet deep. The larger stones are all under 
or at the surface, but they are not striated. The lower deposit is com- 
pact, the stones of small size, and all glaciated and transported a greater 
distance than those above. I found pebbles of the White Mountain por- 
phyries and sienites among them, indicating a carriage of 50 miles. The 


GLACIAL DRIFT. 281 


other hill in the west part of the city is broader, and no excavations of 
consequence are visible. The surface deposit is altogether that of the 
upper till, and identical with that on Munjoy’s. The coarseness of this 
deposit has led to its reference to the usual glacier drift by many geol- 
ogists; but I think its proper place is now found by a reference to the 
upper till, A few have regarded the fossiliferous deposits as of Tertiary 
age, because the upper till overlies them. It is very easy to see how 
such a mistake could be made, if the distinction between the upper and 
lower tills is overlooked. 

An examination of the Champlain deposits shows they do not occur 
upon the tops of these hills, but encircle them, and in strata dipping 
quaquaversally outwards. Fig. 59 is chosen from a locality where Mr. 
C. B. Fuller found mussel shells lying in a position analogous to that 
assumed by the living animals, The siphon-holes above them still re- 
mained, where sand had silted into them from above. Such specimens 
could not have been transported by waves. A list of all the known 
fossiliferous localities is the following: 


Along east side of Munjoy’s hill for 400 yards between Eastern promenade and the 
Grand Trunk Railway. 

Portland Company’s works, St. Lawrence street. 

Adams street. 

Between Fore street and the custom-house. 

Cove on Washington street opposite north end of race-course. 

From this point to Fox street. 

Between Washington and North streets. 

In an old pit on Congress street above Mountfort street. 

Almost anywhere north of Congress street between Alder and Anderson streets. 

Congress street north of reservoir. 

Old slide next canal, described by Prof. E. S. Morse. 

For 200 yards at the foot of Emery street. 

Knightsville,—nodules containing shells, fish, etc.; very abundantly in Deering, 
Woodstock, Cape Elizabeth, and islands in Casco bay. 


A list of the fossils found about this city by Mr. Fuller embraces 5 
vertebrates, 31 crustacea, 2 annulosa, 55 mollusca, 2 echinoderms, and 26 
foraminifera,—121 species in all. Undoubtedly every one of these creat- 
ures lived at the same time in the New Hampshire waters, only a few 
miles distant, where the facilities for their preservation did not exist. 


282 SURFACE GEOLOGY. 


These animals were not exactly the same with those now living on our 
coast, corresponding better with those living farther north. The best 
writers name three different groups for the eastern American coast. 
The arctic fauna is at present confined to the limits of North Greenland, 
and about the pole at the isotherm of 0° C. This is succeeded by the 
Labrador or Syrtensian fauna, extending now as far south as to the mouth 
of the Bay of Fundy. Our present New England or Acadian fauna ex- 
tends from the southern limit of the Syrtensian to Cape Cod, and also 
appears in several places above the lower limit of the latter. The lower 
British Provinces exhibit one or the other of these faunas according to 
the presence of the polar current or the influence of the Gulf stream. 

The fauna of Portland in the Champlain period corresponded to the 
Syrtensian, or the colder one. It seems to have extended as far south 
as Gloucester or Cape Ann. The northern limit of the Acadian fauna 
during the same period was near Point Shirley, Winthrop, Mass. Thus 
the glacial cold was sufficient to bring the boreal life two and a half de- 
grees farther south than it is found at the present day. 

A list of all the Champlain fossils known to occur in New Hampshire 
has been given upon page 165. The whale’s vertebra, cited from Som- 
ersworth, must be eliminated from the list. An inquiry into its authen- 
ticity has indicated that the specimen did not come from the locality 
specified upon the label. 


Tue Grounp Moraine. 


The common masses of drift scattered over the state are known typi- 
cally as ground moraine, such as is accumulated beneath glacial ice. 
The Scotch word for the material is z2//, which is adopted in this report 
to signify the ordinary unstratified glacial accumulations. For reasons 
derived from the Manchester exposures, this term is preferred to a com- 
mon one of boulder clay. The sub-divisions of it have been defined 
upon page 9. We accept the theory there stated, that the lower till is 
the proper ground moraine, and the upper ferruginous division is derived 
from the melting of the ice-sheet. 

Recent studies reveal the existence of curious lenticular-shaped 
mounds of till, some of quite large dimensions. These proved so inter- 
esting that Mr. Upham was asked to devote a season in studying them. 


GLACIAL DRIFT. 283 


He will shortly present the results of this examination, and color upon 
the map of Surface Geology their geographical positions. No feature 
of our drift moraines is so striking as this, and it is singular that pre- 
vious authors have almost universally overlooked or misunderstood it. 

The question has been put to us, As New Hampshire has not been 
submerged since the Helderberg period, and there may have been other 
periods of cold besides the one called par excellence the glacial drift, why 
do we not find moraine accumulations of the earlier ones? I think we 
have abundant evidence of a Triassic glacier in Massachusetts, formed 
of materials partly derived from New Hampshire. The stones of the 
Mt. Mettawampe conglomerate are too coarse to have been moved by 
water alone, and the stones have a glaciated appearance. As there 
seem to be no rocks in our state analogous to the Triassic conglomer- 
ates, we may say, with assurance, that if any glaciation occurred previous 
to the post-tertiary, it could not have antedated the New Red Sandstone. 
It seems probable that Tertiary glaciated beds would be characterized by 
features quickly discernible, and not easily confounded with anything 
else earlier or later. 

But certain beds are brought to our notice, which seem to antedate 
the lower till. The best known is represented in Fig.60. A railroad 
cut in South Lyndeborough, 


two miles west of the station, 
exhibits three layers in the till. 


The top is the familiar loose 
ferruginous earth, such as uni- 


Fig. 60.—SECTION IN TILL, LYNDEBOROUGH. 


versally covers the ground- a. Upper till; b. Lower till; c. Hardpan. 
moraine. Next, 4, is a good 

example of the lower till, full of glaciated pebbles, porphyritic and granitic 
gneisses, mica schist, etc., 5 feet, and in one case 6 feet long. The lam- 
inated appearance arising from compression is clearly defined. Beneath 
this is a coarser mass, reaching to the bottom of the cut, so very com- 
pact that a pick had no effect when struck into it by the workmen; only 
gunpowder or a stronger explosive could excavate it, and it was neces- 
sary that the holes should be bored horizontally near the surface to be- 
come effectual in removing the earth. There is nothing visible in the 
earth itself different from the lower till above it, save that the compo- 


284 SURFACE GEOLOGY. 


nents average coarser. This hardpan is certainly prior in age to the 
lower till; but that circumstance may not compel us to call it Tertiary. 
If length of time is requisite for the induration of till, this hardpan should 
be much older than the common moraine. There is nothing of signifi- 
cance in the shape of this earth heap. It is not as conspicuous as a 
small lenticular hill. After the access of air to the lower deposit, its 
great induration disappears. When it is well exposed to rain, water 
mixes with it, making a compound that will flow readily down a slope. 

A case similar to this is in Pittsfield, midway between Webster's nal 
and the village. The railroad excavators had the same experiences that 
have been narrated for Lyndeborough. Gov. Prescott informs me that 
similar experiences befell persons endeavoring to excavate the earth for 
a well near his residence in Epping; and recently I found the same 
story told of drift in Amherst, Mass., and Hartford, Conn. The exam- 
ples may multiply, and eventually furnish us the answer to our question 
as to the peculiarities of their origin. 


Drirt in Nortu Conway. 


As an example of the aspect of the difference between the ordinary 
till and the modified drift, I would refer to the accompanying heliotype, 
illustrative of these two deposits in North Conway where the road 
crosses Artists’ Falls brook, near the Macmillan hotel. To render the 
sand more distinct, a faint brown color is employed to show its limits. 
It is about 10 feet thick, forming about one fifth part of the exposure. 
There are boulders in the till here about a yard in diameter. The sand 
of North Conway is usually widespread, but very thin. Quite a large 
mass of it, as long as a small lenticular moraine, occurs just to the south 
of the stream opposite the hotel. This is the position from which the 
fine view of Mt. Pequawket, employed for the frontispiece of Volume I], 
was taken. 


Priant Revics oF THE GLaciaAL Periop. Full descriptions of the Hudson’s Bay and Greenland floras 
now existing in the White Mountains have been presented in Volume I, pp. 392 and 568. No better argument 
to show that an arctic climate once existed in New Hampshire than the presence of these plants, as well as the 
corresponding insects described in the same volume, Chapter XII, can be adduced. They also imply the cor- 
rectness of the glacial instead of the iceberg theory of the drift, and also that the cold conditions spread them- 
selves gradually over the continent, disappearing slowly also. 


GLACIAL DRIFT. 285 


Tue DISTRIBUTION OF THE TILL. 


By Warren Uruam. 


Before the glacial period, the rocks of New Hampshire had been 
through long ages subjected to the ordinary disintegrating agencies of 
rain and frost. The loose material derived from this source was doubt- 
less spread with considerable evenness over the surface, collecting to the 
greatest depth in valleys, while on ridges or hill-tops it would be thin or 
entirely washed away. Except where it had been transported by streams 
and consequently formed stratified deposits, the only fragments of rock 
held in this mass would be from underlying or adjoining rocks. 

Through this time temperate or tropical climates generally prevailed; 
but it also seems probable, if the causes of the glacial period have been 
rightly made to depend upon great eccentricity in the earth’s orbit, that 
these genial conditions were at times interrupted by prolonged cold and 
the accumulation of slowly-moving ice-fields similar to the immense gla- 
ciers of Greenland and antarctic lands. Scarcely any hint, however, has 
been obtained in a full survey of our territory respecting these events, 
all records of which appear to have been erased by the last great ice- 
sheet, which pushed from the north and north-west straight forward over 
all the hills and mountains of New England, terminating beyond our 
coast-line. The beds which had been derived from long-continued de- 
composition of the ledges or gathered by previous glacial action, together 
with the thick fluviatile deposits that probably occupied the valleys, were 
ploughed up by this ice-sheet, and thoroughly kneaded with each other. 
Very large amounts of detritus were also added from erosion of the rock- 
surface. Fragments of all sizes and in great profusion were loosened 
and wrenched away, while the ledges were everywhere worn and striated 
by boulders and pebbles which were rolled and dragged along under the 
vast weight of ice, breaking up and grinding themselves and the under- 
lying rock into gravel, sand, and even the finest clay. 

At the end of the glacial period, the material which had been thus 
gathered, mingled and swept along by the moving ice, was left in three 
different classes of deposits, namely, modified drift, upper till, and lower 
till. The first and second of these appear to have been held in the body 


of the ice-sheet, principally in its lower portion. At its final melting, it 
VOL, III, 37 


286 SURFACE GEOLOGY. 


has been shown that the modified drift was swept into the valleys, while 
the upper till, which escaped this erosion, fell loosely upon the surface, 
forming an unstratified, confused mass of boulders, gravel, and sand. 

The characteristics of this upper division of the unmodified glacial 
drift are,—the large size of its boulders, which are usually abundant, be- 
ing often from five to ten, and sometimes twenty or thirty feet in diame- 
ter; the angular form of these blocks, as also of smaller fragments, which 
have seldom been worn or rounded except by the weather; the occur- 
rence of much of its iron in the form of sesquioxide, giving a yellowish 
or reddish color; and the comparative looseness of the whole deposit. 
Its thickness is quite variable, being commonly one to five feet, but 
sometimes reaching to twenty feet or more. This upper till generally 
forms the surface throughout the state, the only exceptions being tracts 
of valley or lowland, where it is covered by beds of modified drift, and 
frequent small areas, varying from a few square rods to several acres, or 
sometimes, especially upon mountains, perhaps hundreds of acres in ex- 
tent, where scarcely any superficial material rests upon the ledges. 

The lower till is distinguished by its smaller rock-fragments, which are 
commonly less than two feet in diameter, and often consist of pebbles 
not exceeding half this size, though occasionally it also contains large 
boulders; by the glaciated form of many of these stones, which are fre- 
quently marked with striz; by the usually clayey detritus, in which they 
are held; by its darker and frequently bluish color, due to the imperfectly 
oxidized state of its iron; and by its very hard and compact structure 
without stratification, boulders, pebbles, sand, and clay being indiscrim- 
inately mixed, but at the same time showing traces of lamination, or per- 
haps cleavage, in planes parallel to the surface, usually noticeable wher- 
ever a section has been for a short time exposed to the weather. All 
these features indicate that this division of the drift was accumulated 
beneath the ice as its ground-moraine. Rough and angular boulders, 
pushed along under the glacial sheet, were worn to small size, having 
their sides planed off and striated; and in the same manner gravel .and 
sand were pulverized to clay. Secluded from air and water, the iron 
remained in the protoxide combinations which it had in the solid rocks. 
Analyses of upper and lower till from Alton, by Mr. Hawes, show the 
following percentages : 


GLACIAL DRIFT. 287 


Upper till. Lower till. 
Iron protoxide, . : i - s : 1.42 1.75 
Iron sesquioxide, . é ‘ : 3 : i 1.56 0.006 


These samples were taken within a foot of each other, close to the line 
of contact of the two deposits. The hardness of the lower till, which 
requires it to be loosened by a pick before it can be shovelled, mak- 
ing its excavation cost two to four times as much as that of the upper 
till, appears to have resulted from the immense pressure of the ice. The 
imperfect lamination, which has been commonly observed in exposures 
of the lower till in New Hampshire, may be due to the same cause, but 
more probably to its accumulation by a gradual increase of depth. It 
seems to show that the ice in its passage added new material to the sur- 
face of its ground-moraine, which generally lay undisturbed below. 

The distribution of the lower till is quite irregular, being much less 
uniform than that of the upper till, It occurs in all parts of the state, 
but is often wanting, and probably does not occupy more than half of its 
area. It is most commonly spread in flattened sheets, which may be 
nearly level, or inclined upon the flanks of hills or mountains. In the 
northern part of the state and among the White Mountains, the unmod- 
ified glacial drift often forms the slopes or rests upon the tops of the 
highest ridges. Its distribution seems to have no reference to the alti- 
tude or configuration of the land. The summits on the highland boun- 
dary between New Hampshire and the province of Quebec, as near Lake 
Magalloway and Mt. Prospect, near Third lake, are described by Mr. 
Huntington as principally covered with till. The same is true of the 
top of Moosilauke, 4811 feet above the sea. Strize show that the ice- 
sheet moved over these elevations from lower areas at the north-west, 
where a large part of its drift was probably collected, to be carried for- 
ward and deposited at a higher level. The summit of Mt. Washington 
is covered by débris (described on p. 205), which seems to correspond to 
the upper and lower divisions of the till. 

Lenticular Hills. In the south part of the state, the glacial drift is 
probably not more abundant than among the mountains, but becomes 
more interesting because of its accumulation in massive, rounded hills, 
principally composed of lower till, which form the most prominent eleva- 
tions near our coast, in Essex county, Mass., and southward to Boston.* 


* These remarkable deposits of glacial drift have been described in the Proceedings of the Boston Soctety of 


288 SURFACE GEOLOGY. 


A special exploration has shown that these hills are also finely developed, 
being more numerous but somewhat less massive, in Merrimack, Hills- 
borough, and Cheshire counties, and in many parts of central Massachu- 
setts. They vary in size from a few hundred feet to a third or a half 
mile in length, with usually about half or two thirds as great width. 
Their height, corresponding to their area, varies from forty or fifty feet 
to one hundred and fifty or two hundred feet. But whatever may be the 
size of these hills, they are singularly alike in outline and form, usually 
having steep sides, with gently-sloping, rounded tops, and presenting a 
very smooth and regular contour. From this resemblance in shape to 
an elliptical convex lens, Prof. Hitchcock has called them /enticular hills, 
to distinguish these deposits of glacial drift from its broadly flattened or 
undulating sheets, which are common throughout the state. 

The lenticular hills have a well defined trend, which shows a very 
notable parallelism with the striation of the rocks. Next to the coast it 
is prevailingly north-west to south-east, while farther inland it has very 
few exceptions from a nearly north and south course. In addition to the 
occurrence of the glacial drift in lenticular hills, it is frequently amassed 
in slopes of similar lenticular form. These have their position almost 
invariably upon either the south or north side of the ledgy hills against 
which they rest, showing a considerable deflection towards the south- 
east and north-west in the east part of the state. It cannot be doubted 
that the trend of the lenticular hills, and the direction taken by these 
slopes, have been determined by the glacial current, which produced the 
striae with which they are parallel. 

Slopes of till accumulated on the lee side of projecting ledges have 
been described by European glacialists, the hill and the detritus sheltered 
behind it being commonly known as “crag and tail.’ The greater por- 
tion of these slopes which have been noted in New Hampshire are shel- 
tered in this way; but about a third of them lie upon the northern side, 
which was exposed to the ice-current. In rare cases these slopes have 
gathered upon both north and south sides alike, blending together and 
assuming the form of a lenticular hill of glacial drift, but having expos- 
ures of ledge at the top. In many true lenticular hills outcrops of solid 


Natural History by Prof. N. S. Shaler (vol. xiii, pp. 196-203), and by Prof. C. H. Hitchcock (vol. xix, pp. 
63-67). They seem to resemble the “ drums”’ or ‘‘ sowbacks”’ of the till in Scotland, mentioned in Geikie’s 
Great Ice Age. 


GLACIAL DRIFT. 289 


rock occur near their base, and evidently form a pedestal capped by a 
rounded mass of till fifty to one hundred feet in depth. 

These hills of glacial drift may be recognized by their smoothed sur- 
faces, overspread, indeed, with the large boulders which are common in 
the upper till, but moulded in gracefully curved outlines unbroken by 
jutting ledges, which give to all our other hills a more or less angular 
and abruptly undulating surface. Our elevations of rock are commonly 
in irregular groups or ridges, with outlying spurs, and, except in the 
south-east part of the state, they are far more massive and prominent 
than the lenticular hills. These accumulations of till are further distin- 
guished by their fertile soil, well adapted for pasturage or cultivation, 
which frequently makes them the most valuable land in the districts 
where they occur. On this account, they have almost invariably been 
cleared, while the more rugged, ledgy hills remain covered with woods, 

During exploration for mapping the lenticular hills, notes were also 
taken of sections in the glacial drift, shown by excavations for building 
and repairing roads, or for wells. These observations are presented in 
the following table, which shows depths of upper till varying from one 
to seventeen feet, resting, in all but five instances, directly upon the lower 
till, their separation being a definite line. It will be seen that thin lay- 
ers of sand are occasionally found in both these deposits, appearing to 
be most frequent in the lower till, where they are sometimes inclined or 
nearly vertical. In most cases where thick beds of gravel, sand, or clay 
occur in the glacial drift, their position is between the upper and lower 
till. A few examples appear in the annexed table, and others are de- 
scribed on pages 108, 131, 137, 159, and 163 of this volume. It will be 
seen, also, from this table, that thick stratified deposits are sometimes 
found in or beneath the lower till. Wells in this compact boulder-clay, 
which is usually impervious to water, often encounter springs issuing 
from these beds or from thin seams or layers of sand, which therefore 
must extend a considerable distance. In most of the sections noted, the 
base of the boulder-clay was not reached. Nearly half of these sections 
are upon lenticular hills or slopes, which are thus shown to consist of a 
thin stratum of upper till at the surface, while the larger central portion 
is a massive accumulation of ground-moraine or lower till. 


290 SURFACE GEOLOGY. 
SEcTIONS OF THE GLACIAL DrirT In NEw HaAmpsuire. 
Thickness in feet. 
LOCALITIES. Upper | Lower REMARKS. 
Till. Till 
Ashland,—2 miles east of village .......- 4 25 a. Three wells, nearly alike in mate- 
Sandwich, —Notch road...see.-seeveee 2 3 rial, about 60 feet above the base of the 
Lenticular slope at south town line. . 3 27 slope. The lower till was here underlain 
Moultonborough,—several places........++++ 2 3-5 by dark gray, loose gravel, “‘like that of 
Tuftonborough, —Fernald’s hill, lenticular a stream,’’ extending 5 feet (not pene- 
slope; resting against ledge at south- trated). "The atgest pebbles of this grav- 
FAS Tes elastase cpster iva vena forohs ba paiesasenn daa dorene 3 10-15, a. | el were 3 or 4 inches in diameter. 
Wolfeborough, —lenticular slope, 2 miles N. 
of village gaps Stoney Soojerstc eas olen AeA tose -aseSe 2-4 20-30 4. Two wells, Lower till underlain 
Near Cotton Valley station....... 4 10 by a water-bearing stratum of sand or 
Ossipee,—Fogg’s ridge, lenticular hill. } 17 fine gravel. 
Alton,—¥% mile west of Alton Bay.. 2 3 Je c. Specimens analyzed. 
Gilmanton, —several places........- I-2 10 
Sanbornton, —west of Hopkinson hill . 2 3 
Tilton,—2 miles north of village........ 2 5 
Rochester,—top of Haven hill, lenticular . 3 37 
At Walter S. Hussey’s, on south slope 
of a lenticular lillsnsc-wenscveas cinaes oie 3 20 
At J. E. Chesley’s, % mile south- east 
from last, on north slope of a lenticu- 
Var hillhso-seisssrerra as etisaveae arene 5 bey 
Strafford ,—2 miles south-east of Bow lake.. % 3 
Pittsfield, —Tilton hill, lenticular slope, rest- 
ing againt ledge at south-east ......... 1-2 20 
Loudon,—1 mile east of Hot Hole pond...... 3 5 |a@. 
Lenticular slope x mile south-west of 
Clough spon dis acscarsesneiniocarndereniiciesiceceotorive sch 5 15 ad. Very irregular in contour. 
Canterbury,—¥ mile east of centre. rt a 
rt mile Souths west of centre...... 2-5 to | a. 
Concord,—r mile north of East Concord. ‘ 2 8 
Road to St. Paul’s School. 2 3 
South-west side of Rattlesnake hill . 1% 3 
Hopkinton,—lenticular slopes on south side 
of Beech hill, at A. P. Ober’s...... 4 36 | e. e. Lower till contains occasional lay= 
C. H. & H. Merrill’s.. 1% 18 | e. | ers of sand a few inches thick. 
fs AG Ss. Johnson’ Shafiaicsspainate 2 32 
In south-west part of town......-....0.. I-2 5 
Warner,—Pumpkin hill, lenticular in form, 
with small exposure of ledge at top . 2 20 
Andover,—at west town line..............-. 2 3 J. Lower till underlain by a water- 
New London,—at Institution, upon a broad bearing stratum of gravel. 
lenticular hill.............006 ‘ 2 43 17 g. Lower till showed two or three 
¥% mile south-east from last . er 1% 26 | g. | seams of sand, 1-5 inches wide; it is un- 
Washington,—hillside south-east of i, en derlain by a softer clayey stratum, 1 foot 
pond.. 2 18 thick, resting on ledge. 
Sullivan, Harr 
DIACES sei sinareslon-eeaiens Seatac aN 14-3 5 
Swanley 17 miles south of Wilson’s pond. 2h 3 
New Ipswich,—north-west part........-..4- 1% 5 
ee north-east of village, at north | _ 
foot of 2 lenticular hill.............66 1% 4 | A. A’. Lower till underlain by 5 feet of 
Greenfield,—% mile east of Cragin pond, on stratified sand, which continues below 
ees ar ak resting against ledge the excavation. 
AEMOTED 6 :csenivvevenrsininersseioutanver nea wanranas 2% 20 
¥y mile farther east, at “north-west foot of is 
Lyndeborough mountain. ........-...5 1% 26 z. Lower till contains occasional lay- 
Bennington,—east part, on south end of a ers of sand, 1-2 inches thick. 
lenticular hill....esccceaccceee seuss 5 i% 20 | 2. Fr : 
Wilton,—north-west part, at county farm. 1% 15 : ._ Upper till contains layers of sand, 
¥% mile north-east of East Wilton : 12 ro | 7. | 3-6 inches thick. 
¥ mile west of East Wilton..........005 15 Jesssveccee| Ae 
New Boston, at S. Dodge’s, on south slope k. Upper till contains layers of sand, 
of a lenticular hill ..... ued ecdadh heatsrecea 6 10 Z. | and is underlain by ro feet of stratified 
Beard’s hill, lenticular, on its south slope. 5 15 clayey sand, which extends below the ex- 
¥y% mile east of last........ wieisialnrenys 2 4 cavation. 
¥, mile north of village, on east side ofa. 
lenticular hill............. 3 17 | wt. 2. Two wells. The upper and lower 
Cochran’s hill, lenticular, on its north” till were here separated by a stratum, 5 
SLO PC arereiaiais ox\esreranvre anomie ateiane 2 35 feet in thickness, of very compact ferru- 
At the south-east foot of Wason hill...... 9 6 ginous earth, free from pebbles. The 
Amherst ,—lenticular Mass upon Chestnut lower till contains occasional thin layers 
hill, % mile east of O. Carter’s........ 6 15 of sand. 
Goffstown, —on south slope of a jentiaules: 
hill, 2 miles north-west atom Centre.. 4 1B | 2. m, A nearly vertical seam of ferrugi- 
x mile north of TAS bnce center crane 2 3 nous sand, 1-1% feet wide and ro feet 
Stratham,—top of lenticular hill, 1 mile west long, was exposed i in this lower till. 
of Rollins hill. .ccccccccccecuvcueuuces 3 40 


GLACIAL DRIFT. 


291 


Kingston,—lenticular mass, on south-west z. Two or three seams of sand, in- 
Sidesof Great hil a venaGcaeindocmavasieniawints 5 25 clined 45°, 3-6 inches wide and several 
East Kingston,—lenticular mass, on south- feet long, occur in the lower till, which is 
east side of Great hill................ 3 60 underlain by a stratum of black clayey 
Kensington,—Moulton ridge, lenticular hill, sand 1 foot or more in thickness. 
At LOD avs iecessresasarsinsiaraeoveroinvetonagiaie wean a aire 10 30 o. Upper and lower till separated by 
priile south Of 1460 occu ourwew yp civesaxs 17 5 a layer of sand 4 inches thick. 
Top of lenticular hill, south of Muddy i 
PONG sa vacscerais-viorarerscenersienste aeieienein Sees 5 15 p-. Upper and lower till separated by 
North-west slope of same hill........... 13 15 | %. | 6 inches of waterworn gravel. 
South Hampton,—north-west village......... 6 10 


The average thickness of the upper till, obtained by taking the mean 
of these observations, is three feet and nine inches. If we subtract one 


tenth of this, due allowance will probably be made for areas that are 


» 


Fig. 61.—SECTION OF GLACIAL DRIFT, TWO MILES EAST OF ASHLAND, 
illustrating the usual mode of occurrence of the upper and lower till 
throughout the state. 

Thickness of the upper till, 4 feet; of the lower till, 25 feet. The most 
abundant boulders in the former were porphyritic gneiss; in the latter, 
Montalban. 


destitute of this deposit, leaving three and one third feet, which would 
thus appear to be approximately the mean depth of the upper till, if it 
were spread in a sheet of uniform thickness over the entire state. 

The lower till, however, does not appear to have any development 
upon half of this territory, being accumulated in patches, sheets, and 
lenticular masses, while over adjoining areas of equal extent the ledges 
are exposed or covered only by the upper till. Very few of these sec- 
tions show the whole thickness of the lower till; and its depth in the 
lenticular hills affords no basis from which to judge of its other deposits. 
It is impossible, therefore, to arrive at an estimate, as before, from this 
table. If we still wish to form some conclusion respecting the entire 
mass of the ground-moraine, it will be well first to consider the lenticu- 
lar hills and slopes, of which about eight hundred and sixty have been 


292 SURFACE GEOLOGY. 


noted in southern New Hampshire. The portions of these which con- 
sist of lower till may average equal to a depth for each of fifty feet upon 
an area of one tenth of a square mile. This indicates that the lower till, 
accumulated in such masses, would form a layer perhaps six inches thick, 
if evenly spread over the whole state. These hills and slopes are only 
found, however, upon small portions of this area, and for the districts of 
their greatest abundance in Cheshire and Hillsborough counties, as in 
portions of Walpole, Chesterfield, Dublin, Jaffrey, Rindge, New Ipswich, 
Temple, Wilton, New Boston, and Goffstown, would probably yield con- 
tinuous sheets five to ten feet in thickness; while in Kensington and 
South Hampton, which represent their greater development near the 
coast, they may be equivalent to a uniform depth of thirty or forty feet. 
The average thickness of the lower till in flattened deposits, found 
throughout the state, can only be conjectured. It varies in depth from 
a few feet, as is most common, to twenty, thirty, or perhaps sometimes 
fifty feet. Our impression of its aggregate amount, including the lentic- 
ular hills and slopes, is nearly the same as the estimate derived from 
the foregoing table for the upper till. The modified drift, described in 
the first chapter of this volume, must also be nearly the same in its total 
mass. 

The whole depth of the drift in New Hampshire, if uniformly dis- 
tributed, would therefore be something like ten feet, of which nearly 
equal portions occur in each of its three divisions of modified drift, upper 
till, and lower till or ground-moraine, In this connection, we must bear 
in mind that a considerable part of the drift gathered by the ice-sheet 
from our territory was carried beyond our coast-line and deposited in 
submarine banks. 

The distribution of the till has been carefully noted throughout that 
part of the state which lies south of Grafton county and the White 
Mountains. Its most interesting deposits are the lenticular hills and 
slopes. These have been represented in the atlas, on the map that shows 
the courses of striz. It will be seen that their longer axes agree in 
direction with these tracings of the ice-current. The same map also 
shows lines of contour, with which the irregular distribution of the len- 
ticular hills may be readily compared. It would be expected that their 
abundance or absence must be determined, or at least influenced, by the 


GLACIAL DRIFT. 293 


very irregular outlines of the surface; but we have been unable to dis- 
cover this relation or dependence, if any exists. In the northern por- 
tion of the area explored, the till is common in patches and extended 
sheets, but forms only few and scattered lenticular hills or slopes. Far- 
ther south, these remarkable accumulations occur quite abundantly upon 
three belts of our territory, one of which extends through the west part 
of Cheshire county; another, from Goffstown and Weare south-west to 
New Ipswich and Rindge; and the third, through eastern Rockingham 
county. The general features of these lenticular deposits of till, which 
have been already given, apply to them in all parts of the state where 
they have been found, and also in north-eastern and central Massachu- 
setts, leaving little that needs to be particularly mentioned, except the 
localities of their most conspicuous or noteworthy occurrence. 


Sullivan County. The glacial drift does not form many prominently rounded masses 
in this part of the state. A lenticular slope of till, resting against higher ledges at the 
north, was observed two miles west of Meriden on the north side of Blow-me-down 
brook. Even such deposits are rare in most of the towns of this county. Southward, 
lenticular accumulations of till were noted on both sides of Sugar river one to two miles 
east of Claremont. The first of these on the north side of the river falls off abruptly 
at its south-east end, having evidently been undermined by this stream, which now 
flows thirty rods distant, separated by a low flood-plain. No lenticular masses were 
seen in Newport, but considerable till is spread out in flattened sheets. For fully a 
mile in the west part of this town, beginning a little below Kelleyville, such a deposit 
has been undermined by Sugar river, and forms a continuous bluff on its north side 75 
to 100 feet high. The slope southward from Acworth centre to Cold river, amounting 
to about 500 feet in two miles, is principally covered with till, much of which is massed 
in rounded hummocks with several lenticular hills near the bottom. At the northward 
bend of the river, a half mile west of South Acworth, it forms a bluff roo feet high 
The ascent on the south side of the valley towards Alstead is also marked by frequent 
patches of till.* 

Cheshire County. In the west and south-east parts of Cheshire county the lenticular 
hills are finely developed, but they are almost entirely wanting over an intervening area 
which averages ten miles in width. At East Alstead, and fora mile to the north and 
east, the surface is mostly till, which occurs in broad swells, resembling lenticular ac- 
cumulations. Well marked examples of ‘‘crag and tail” occur one mile north-east and 
a mile and a half east-north-east from this village, the latter example being in the edge 
of Marlow. Many fine lenticular hills occur in the south part of Walpole, scattered 
among more prominent hills of ledge. Ata mile and a half south-east from the village, 
the road which leads north from school-house No. 4 climbs a rounded slope of till nearly 

VOL, 111. 38 


204. SURFACE GEOLOGY, 


200 feetin height. From its top two prominent hills of this class are seen within a third 
of a mile on the west. Another fine example was noted about a mile south from these; 
two more occur a mile west from the last; and several were seen in the south-east part 
of the town, one lying a short distance north-west from school-house No. 13, and others 
within a mile to the west and south. : 

The valley of Thompson brook, in the south-west corner of Alstead and north part 
of Surry, is bordered by large deposits of till, which at several places have a well defined 
lenticular form. These hills are also well shown along the Ashuelot valley in Gilsum. 
In Westmoreland they are numerous along the route of the Cheshire Railroad, occur- 
ring close north of East Westmoreland depot, at one mile west and south-west, and for 
one mile to the south. No typical lenticular hills were noticed near Westmoreland 
village, but similar masses of till rest against a ledgy hill one mile south-west; and at 
a mile and a half south a broad sheet of it forms the north slope of Pistareen mountain. 
These hills are very finely shown in Chesterfield, as many as fifty distinct lenticular 
accumulations being noted. They abound from Factory village west to Connecticut 
river, being especially numerous and massive within a circuit of one mile about Ches- 
terfield centre. Only inconspicuous examples occur in Hinsdale; but Winchester has 
about a dozen well defined and prominent lenticular hills within four miles north from 
Ashuelot and Winchester villages. These constitute an isolated group, surrounded on 
all sides for three or four miles by irregular ledgy hills with no considerable accumula- 
tions of till. In each of these towns, other areas adjoining those which we have de- 
scribed are destitute of these deposits. 

The central portion of this county, which has only very rare lenticular hills, comprises 
the towns of Marlow, Stoddard, Sullivan, Roxbury, Keene, Swanzey, Troy, Richmond, 
and Fitzwilliam. In Nelson, these hills are found near the village. -Several good ex- 
amples, 50 to 75 or 100 feet deep, occur within a half mile to the south-east and within 
a mile and a half to the west. In Harrisville and Marlborough a few lenticular hills 
are noted; but the greater part of these towns shows no trace of them. 

Their best display in this county is at the south-east, in Dublin, Jaffrey, and Rindge. 
On the north side of Monadnock mountain they are finely developed, four very promi- 
nent examples occurring about two miles north-west from Monadnock lake, which is 
also bordered by small but typical lenticular hills on its north-west side. Their trend 
here is uniformly from north-west to south-east, or nearly so, while in other parts of 
this county it is almost always approximately from north to south. This divergence of 
45° from the usual course was due to deflection of the ice-current, for the striz of this 
vicinity show the same eastward deviation. Between Dublin village and Thorndike 
pond numerous lenticular accumulations occur; but many of them are not true hills, since 
they rest against ledges at the north. The east half of Jaffrey and nearly the entire 
township of Rindge are well filled with the lenticular hills, which vary from 50 to 150 
feet in depth, but scarcely any of them have received special names. Their fertility 
has caused them to be cleared, and their smoothed fields of pasturage or mowing con- 
trast notably with the ledgy hills of similar height but very irregular outlines, which 
abound in the next fifteen miles to the west. 


GLACIAL DRIFT. 295 


Carroll County. The lenticular accumulations of till which have been observed east 
of Lake Winnipiseogee lie most frequently on the north-west side of hills, which was 
struck by the full force of the ice-current. The hill upon which Sandwich Lower Cor- 
ner is built may serve as an example. The north side of this hill is a smooth lenticu- 
lar slope of till, but ledge appears at its top and on its south side. Fernald’s hill in 
Tuftonborough, a mile east of Melvin Village, also has a very regular north and north- 
west slope of till. A bed of stratified gravel and sand occurs in the lower till of this 
deposit, as shown by wells at Mr. Calvin Fernald’s, described on page 290. The high- 
est point of this hill is ledge, which forms all its south-east side, being in many places 
precipitous. A similar mass of lower till, with modified drift beneath or enclosed in 
it, lies on the north-west side of a hill two miles north-east of Wolfeborough village. 
Pray hill, north of Pine River pond in Wakefield, has a fine north-west slope of till, 
while its south-east slope is ledge. Fogg’s Ridge, one mile south of Pocket hill in 
Ossipee, is the only true lenticular hill seen in Carroll county. This is a typical exam- 
ple, showing no ledges for roo feet below its highest point. Its whole north-west and 
north slopes appear to be composed of till; on the south and south-east, ledges form 
the base of the hill, extending half way to its top. Its trend, like that of the slopes 
of till, is approximately north-west to south-east. 

Belknap County. The till south and west of Lake Winnipiseogee is sometimes ac- 
cumulated deeply on the north-west slopes of hills, as in Carroll county, but more 
commonly it is massed on the south-east or sheltered side. Prospect hill in Alton, and 
Ayers hill in the edge of Barnstead, four miles farther west, are fine examples of ‘‘ crag 
and tail,” the till lying only upon their south-east sides, having, in the first case, a very 
straight slope, and in the latter a rounded, lenticular form. Similar masses of till rest 
upon the south and south-east sides of Hall’s hill, one mile north-east of Gilmanton 
Iron Works. Several small lenticular hills occur near Half Moon pond, which is 
crossed by the line between Alton and Barnstead; others were noted five miles farther 
south, near Clark’s corner; and a fine example lies three fourths of a mile south-east of 
Lower Gilmanton. Far the greater part of these townships, however, are destitute of 
any such deposits ; and in the remainder of the county, towards the north-west, lentic- 
ular hills and slopes are still more rare. 

Merrimack County. The lenticular accumulations of till are well shown in several 
of the towns of this county. They are most numerous from Pittsfield westward to the 
Merrimack river. Farther west, typical hills of this class are very rare; but we occa- 
sionally find massive lenticular slopes, or broad, flattened swells, of till. The north, 
west, and south-east portions of this county have scarcely any examples of these de- 
posits. 

In Pittsfield, the north-west slope of Tilton hill, two miles east of the village, con- 
sists of three rounded masses of till, but ledges form its top and east side. Much 
glacial drift is accumulated west of the Suncook in this town and the north part of 
Chichester, forming lenticular hills, of which Perkins’s, Prospect, Jenness, Leavitt, and 
Brown’s hills are good examples. Two of these hills occur in Loudon north of Rollins 


296 SURFACE GEOLOGY. 


pond; three more west of Crooked pond, near a saw-mill; and four were noted near 
together south-east of Clough pond. Others are scattered here’ and there through these 
towns and the south half of Canterbury. The most elevated of these bunches of till 
lie on the north-east slope of Garvin's hill in Chichester, near its top, and similarly on 
Oak hill in Loudon, both of which are principally ledge. Fora third of a mile next 
above Webster's mills in Chichester, the Suncook river has cut its channel fully 75 feet 
deep through an accumulation of till, which appears to have rested against a ledgy hill 
on the south-east. This till forms bluffs that rise very steeply from the river on its 
north-west side. The finest development of lenticular hills seen in this county is in 
Concord, north-east of Snow pond, where a group of seven or eight is included within 
half a mile square. Ata mile and a half to the north-west, another example with a 
double summit is crossed by the north line of this township. 

West of the Merrimack river, Horse hill in the north-west corner of Concord, and 
several smaller rounded masses at its south-east foot; Beech hill, at the east line of 
Hopkinton, at least on its slopes both to the north and south; the massive north slope 
of Putney hill, well seen from Contoocookville; Gage’s hill, one mile west of Hopkin- 
ton village; several small accumulations in Dunbarton; and Gove’s hill, north of 
Gove’s pond in Henniker, belong to this class. In Webster, till forms deep accumu- 
lations sloping to the north, at Corser Hill village; west of Long pond; and on the 
north side of Little’s hill. Glitten’s hill in this town, and Pumpkin and Burnt hills in 
Warner, are very massive hills of typical lenticular form. They have outcropping 
ledges at their tops, while their slopes on all sides are composed of till. In Salisbury 
till forms the south-east slope of Lovering’s hill, and the gentle swells upon which the 
south and central villages are built. In Andover it is prominently massed in south- 
ward slopes west of Highland lake. Its most notable accumulation in the west part of 
this county is at New London village, where it forms a broad rounded swell nearly a 
mile long. The trend of these deposits in Merrimack county is generally north-west 
to south-east, varying in Canterbury, the west part of Loudon, the north-east part of 
Concord, and in Dunbarton to a course more nearly north and south. 

fiillsborough County. The north-west and south-east portions of this county are 
nearly or quite destitute of any lenticular masses of glacial drift. They are, however, 
sprinkled very abundantly over a central area ten to fifteen miles wide, which extends 
across the county from north-east to south-west, being connected beyond its limits 
with the conspicuous development of these hills already described in Dublin, Jaffrey, 
and Rindge. 

Beginning at the north-east, we find a very remarkable group of lenticular hills, 
about twenty in number, north of the principal village in Goffstown. Two prominent 
examples occur a mile east from these, but no others were observed in this whole town- 
ship. Five miles to the west these hills are again well displayed in the south part of 
Weare. The massive south-east slope of Dearborn’s hill, and the top of Chevy’s hill, 
which lies north-west of Clinton Grove, are also till. In the latter case it forms a 
rounded mass crowning a high ledgy hill, while scarcely any other lenticular accumula- 


GLACIAL DRIFT. 297 


tions are to be seen for miles around. Several of these hills and slopes occur in Deer- 
ing, the most massive being on the east side of Wolf hill, and a southward slope from 
the hill-top west of Chase pond. 

Three or four prominent lenticular hills were found in the edge of Bennington and 
north-west corner of Francestown, at the north side of Crotched mountain. Others 
lie in the east part of Francestown, north of Haunted pond. New Boston, except at 
its east side, is well dotted with lenticular hills, of which Beard’s, Clark’s, and Cochran 
hills, one close north of Mr. Solomon Dodge’s house, two or three others within a mile 
to the north-west, one north of the first saw-mill below the village, others north and 
south-west of Cochran pond, a mile south of the village, and one less than a mile 
north-east of Joe English hill, are typical examples. Bedford has a few of these hills, 
the finest of which, a mile north-east of the village, is well seen from Manchester. In 
Amherst the south slope of Walnut hill is till, which also forms three lenticular hills 
one to two miles north-west, and several rounded masses on the south side and near 
the top of Chestnut hill. Prospect hill in Mont Vernon, and several southward slopes 
south and south-west of the village, belong in the same class. 

These hills are absent from the west part of Mont Vernon, most of Lyndeborough, 
and the middle of Francestown; but in the east part of Greenfield they are finely de- 
veloped. Two miles north-east of Russell’s crossing, till lies in rounded masses on the 
north-west slope of Lyndeborough mountain. It also forms a smooth area of several 
acres near its south-west summit, and is spread in extensive sheets on its south-east 
side. 

In Wilton, Temple, Greenville, and New Ipswich, the lenticular hills are abundant. 
Fine examples occur in the edge of Milford, two thirds of a mile east of Wilton depot; 
upon Perham hill, in the north-east corner of Wilton; a mile to the north-west in the 
edge of Lyndeborough; several in the north-west and others in the south-west part of 
Wilton; four within one mile north-east of Temple village, known as Follett, Walton, 
Howard, and Wilson hills; Nobby hill in Mason, one mile south of the village; Bel- 
lows and Campbell hills in Greenville, and another north-east of the depot; Jefts hill 
in New Ipswich, one mile west of Greenville, with others close south-west and one 
half to one and a half miles north-west; several one mile south and south-west of New 
Ipswich village ; and three on the west side of Barrett mountain. 

A few hills of this class are found in Peterborough, being most numerous about 
Cunningham pond; also in Sharon, which has near its south-west corner one of the 
finest examples seen in New Hampshire. The trend of these hills and slopes through- 
out this county is almost invariably towards the south, or ten to twenty degrees east of 
soutn. 

Strafford County. No lenticular hills or slopes were found in the north part of this 
county. Rounded masses of till occur at several places on the south-east side of the 
Blue hills, south-east of Merrill’s corner, and in prominent ridges near Strafford corner 
and centre. In Rochester five lenticular hills were noted, the finest of them being 
Hayes hill, now owned by Walter S. Hussey. This rises with a very regularly rounded 


298 SURFACE GEOLOGY. 


outline 150 feet above the lowland or valleys which surround it on every side. Another 
of similar height, but less typical in form, lies one mile south-east, near Gonic village. 
Two of these in Rochester occur east of the Cochecho, being Haven hill crossed by 
the road to Great Falls, and Gonic hill a half mile south. The former is less steep and 
prominent than usual, but was shown by a well at its top to be composed of glacial 
drift at least forty feet deep. 

Green hill in Barrington is principally till in three lenticular masses, but ledge occurs 
at its north-west summit. Dover has two prominent lenticular hills, neither of them 
typical in form. Long hill represents one extreme, being more elongated than usual, 
with the nearly north-west to south-east trend which prevails in this county ; and Gar- 
rison hill, which rises steeply about 150 feet, is at the opposite extreme, being nearly 
round. Farther south, the only lenticular accumulation of till seen in this county is 
Wednesday hill in Lee. This is a good example of these hills, rising 75 feet above the 
land on all sides. Its nearest neighbors of the same class are Bald and Grapevine hills 
in Newmarket, five miles distant. 

The towns of Maine which border this county on the south-east similarly contain 
scattered lenticular hills, of which Butler's hill, close east of South Berwick, and Third 
and Frost hills in Eliot, are very fine and prominent examples. 

Rockingham County. Deerfield is the only town in the western half of this county 
which shows frequent lenticular deposits of till. They were noted at about one mile 
from Deerfield centre towards the north-east, north-west, west, and south-west. Ata 
mile and a half towards the south-east are two fine hills of this kind, with the north 
summit of Mt. Pawtuckaway one mile farther east. Southward through this part of the 
county lenticular hills are very rare, the only examples discovered being Waterman's 
hill in the north part of Derry, a small one a fourth of a mile north-east of West Hamp- 
stead, one close north-east of Salem depot, and Spicket hill, east of Salem village. The 
last is very massive, and is associated on the east with the extraordinary development 
of these hills through the north part of Essex county, Mass. The only other lenticular 
hills observed west of the Boston & Maine Railroad in Rockingham county are Red 
Oak hill in Epping, the top of which is till, with its whole south-east slope; Dimond 
hill, and several others in the east part of this town; Grapevine and Bald hills in the 
south-west corner of Newmarket, the latter a very fine example, 150 feet in height; 
Deer hill in Brentwood, one mile north-west of Marshall’s corner, also typical, about 
1oo feet in height; Beech hill in Exeter; and the several rounded masses of Great hill 
at the north-east corner of Kingston. 

In Newington, Portsmouth, Rye, and a width of four or five miles next to the ocean 
southward, these hills are entirely absent, if we except the single instance of Great 
Boar’s Head, described on page 254. Stratham has a few fine examples, as Stratham, 
Barker’s, Bunker, and Rollins hills. Three occur within one mile east of Exeter vil- 
lage, and others one to two miles farther south-east. In the five miles next to Massa- 
chusetts line, these deposits of glacial drift are very numerous and massive, being more 
conspicuous than anywhere else in New Hampshire. They are 100 to 200 feet high, 


GLACIAL DRIFT. 299 


and are the only prominent hills in this region. Nearly all of them have received 
names, including Sweet and Brandy Brow hills, one and two miles east of Plaistow ; 
Morse or Falls hill in East Kingston, and Buzzell, Martin, and Hog hills, crossed by 
the east line of this township; Moulton Ridge, Hoosac, Round, Gove, Conner, Ward’s, 
Horse, and New Found hills in Kensington; Cock and Great hills in Hampton Falls ; 
and Indian Ground, Chair, Sawyer’s, Aspen, and Bugsmouth hills in South Hampton. 

The longer axis of most of these hills noted in the west part of Rockingham county 
trends to the south-south-east; in Epping, Newmarket, and Brentwood, to the south- 
east; while those last described have almost invariably an east-south-east course. In 
Kensington and South Hampton, besides this trend of separate hills, we may detect 
their succession in two series which extend from north-west to south-east. One of 
these embraces, in order, Buzzell’s hill, Moulton Ridge, Hoosac, Gove, Conner, Ward's, 
and Horse hills; the other consists of Martin, Hog, Indian Ground, and Chair hills. 
The two last named are double lenticular masses, the higher portion of each being at 
the north-west. 

Lenticular Hills in Massachusetts. These remarkable accumulations of till are very 
abundant and conspicuous over the greater part of Essex county, Mass. The principal 
exceptions to this are the east part of Salisbury; Newburyport; an area several miles 
wide extending thence to the south-west; Cape Ann, eastward from Essex river; and 
the vicinity of Salem. Prominent lenticular hills in this county are Grape, Beech, 
Butts, Monday, and Powow hills in Salisbury, the last of which is perhaps their finest 
type found in all our exploration; Whittier’s and Pond hills in Amesbury; Bear and 
Red Oak hills in Merrimac; Great, Golden, Silver’s, West Meadow, and Scotland 
hills in Haverhill; Bear hill in Methuen; Reservoir hill in Lawrence; Prospect hill in 
Andover ; Gage’s hill and others about Great pond in North Andover; Hazeltine and 
Dead hills in Bradford; Bald Pate hill in Georgetown; Long, Pipe Stave, Archelaus, 
llsley’s, and Crane Neck hills in West Newbury; the Old Town hills in Newbury; Ox 
Pasture, Hundslow, and Prospect hills in Rowley; and Turkey, Bartholomew, Turner’s, 
Scott’s, Town, Heartbreak, Plover, Sagamore, and Castle hills in Ipswich. Nearly all 
of these come within the limits of the map of these deposits, presented in the atlas of 
this report. Others occur farther south in this county. 

Lenticular deposits of till are also very conspicuous in the vicinity of Boston. They 
form many of the islands in the harbor, and the numerous prominent hills that occur 
in the city and for five miles to the north and west, in the towns of Winthrop, Revere, 
Chelsea, Everett, Malden, Medford, Somerville, Cambridge, Watertown, Brighton, 
Newton, and Brookline. 

The trend of these hills in Essex county is prevailingly towards the south-east; but 
some of them vary from this to nearly north and south, while others have their longer 
axis from west to east. Perhaps one fourth of them, however, are nearly round, hay- 
ing no well marked trend. This form is rarely seen in New Hampshire. About Bos- 
ton their course is quite uniformly from north-west to south-east. 


In the north part of Middlesex county lenticular hills of glacial drift are rare, but are 


300 SURFACE GEOLOGY. 


represented by a few fine examples, as Fort hill in Lowell, on the east side of Concord 
river; Forest hill at the south-east edge of Dunstable, with another close north-east; 
and Blanchard’s hill, with two others at the north-east, situated near the north line of 
Dunstable, west of Salmon brook. They are wanting in Pepperell and Townsend ; but 
a prominent one is crossed by the east line of Ashby north of Lock’s brook, and they 
are quite numerous in the next ten miles to the west. 

In Groton and Ayer, lenticular hills are well shown along the east side of the Worces- 
ter & Nashua Railroad. Thence to the south-west they are rarely seen till we reach 
Worcester, where they are again abundant, especially for three or four miles north and 
west of the city, varying from 50 to nearly 200 feet in height. Reservoir or Chandler’s 
hill, Newton, Prospect, and McFarland’s hills are good examples. 

Westward from Ayer along the Fitchburg Railroad, they occur at Shirley station, in 
the south part of Lunenburg, and prominently north and north-west of Leominster. At 
Fitchburg, and for several miles to the west and north-west, all the hills are ledgy with 
no important accumulations of till. Their notable abundance in New Ipswich and 
Rindge continues into Ashby and the north part of Ashburnham; but the next five 
miles to the south and south-west showed very few lenticular hills. 

In Gardner, they again become numerous and prominent, Cowee’s and Parker's hills 
being very conspicuous examples. From their tops as many as twenty of these hills 
are visible, mostly within two or three miles. Parker's hill is separated by a hollow of 
about 40 feet from a contiguous lenticular hill that rises at about twenty-five rods north- 
east to a nearly equal height. At the bottom of this depression, which is 100 feet above 
the foot of the hill in each direction, a former water-course, fifteen to thirty feet wide 
and four or five feet deep, filled with boulders from among which all the earth has been 
swept away, extends from north-west to south-east twenty rods or more. Its explana- 
tion seems to be, that while the ice-sheet was melting over this area, portions remain- 
ing at the north-west side of the hill turned a stream through this gap. 

On Plate xviii of the second volume of this report, Prof. Hitchcock has shown the 
position of prominent lenticular hills in Bernardston and the north part of Gill. He 
also reports their occurrence in the north part of Montague; in Amherst, where Mt. 
Pleasant, other hills at the north and north-east, and the College hill are examples, also 
the hills in the south part of the town, called Castor and Pollux; in South Hadley, 
Prospect hill near the Seminary being of this class; and in the west edge of Granby. 

The trend of these hills in the north part of Middlesex county is between south and 
south-east; about Worcester, Gardner, and Amherst, it is nearly north and south ; 
while in Bernardston and Gill it is commonly a little to the west of south. Probably 
lenticular hills cccur at many other localities in this state, which has been specially 
explored for this report only in its north-east portion shown upon our map. 

Cape Cod and Long Island. A hasty journey has been taken upon Cape Cod and 
Long Island, with a hope that some examination of the drift deposits near their south- 
ern limit might lead to a better understanding of the various questions suggested by 
exploration in New Hampshire. The description of Plymouth and Barnstable coun- 


GLACIAL DRIFT. 301 


ties in the geological report of Massachusetts, and of Long Island in that of New York, 
seemed to indicate that these areas would show lenticular hills; but no accumulations 
like those which we have been describing under this name were seen. 

The greater part of southern Plymouth county was found to be covered with modi- 
fied drift. Much of this is spread in level plains, which in Middleborough have many 
shallow depressions that are occupied by swamps. In the west part of Plymouth the 
only hollows which break the plains are of small area with steep sides, containing 
ponds. These are so numerous that this township is said to have a pond for each day 
in the year. About Plymouth village the modified drift forms kamie-like hillocks and 
small plains, which are separated by very irregular hollows and valleys. The tops of 
these deposits have a nearly uniform height which varies from 100 to 125 feet above 
the sea. 

In the east part of Plymouth a massive ridge, known as Manomet or Rocky hill, ex- 
tends three or four miles from north to south, having a continuous height 300 to 400 
feet above the sea. Abundant angular boulders of all sizes up to twenty feet in diam- 
eter strew its surface, which seems to have no ledges, but to consist entirely of the 
very coarse glacial drift that we have called upper till. At the north end of this range 
the sea has undermined its base, forming a steep slope sixty feet in height. A section 
here showed twenty feet of upper till, yellowish, with abundant large and small boul- 
ders, nearly all of them angular, underlain by lower till, dark bluish gray, with small 
glaciated stones, exposed for twenty feet vertically but concealed below. The bed 
of boulders which forms the shore at this point came mostly from the upper stratum; 
their sharp corners and edges have since been worn away by the waves. This ridge 
is bordered on both sides by kame-like or nearly level areas of modified drift. 

Southward, a broken range of lower hills, composed of the same coarse till, continues 
through Plymouth, Sandwich, and Falmouth. Thence it bends to the south-west, 
forming the chain of the Elizabeth islands. The highest elevations of this series of 
hills in Sandwich are about 300 feet, and in Falmouth and upon Naushon and the 
islands farther west, nearly 200 feet above the sea. Its length, from Manomet hill to 
the end of the Elizabeth islands, is forty-five miles. 

Railroad cuttings thirty feet deep in these deposits, one mile north of Falmouth 
village and Wood’s Hole, show only the upper till. All of Naushon island consists of 
the same material upon the surface, namely, mingled boulders, gravel, and sand, wholly 
unstratified. The boulders are often so abundant as to cover all the ground, and are 
of all sizes up to ten, or even twenty or thirty, feet in diameter. They are almost inva- 
riably angular, except as they have been rounded by exposure to the weather, none of 
them, so far as observed, being glaciated or water-worn. Cliffs forty or fifty feet high, 
which are being undermined by the sea south-west from Tarpaulin cove, appear to be 
composed entirely of this coarse upper till; but on the north-east end of the island a 
well sixty-seven feet deep passed through this deposit, and“its last twenty-two feet 
were in very hard lower till, dark gray in color, with glaciated pebbles. 


The contour of this island, as also of many localities throughout the whole series of 
VOL. Ill. 39 


302 SURFACE GEOLOGY. 


these hills, is very irregular, consisting of hills, ridges, and rounds, with bowl-shaped 
hollows which frequently contain ponds. This feature has led some to regard these 
deposits as similar to kames.* Their material, however, is very different from that of 
the kames, which consist principally of stratifiéd water-worn gravel, rarely containing 
any large or angular boulders, but frequently intermixed with layers of sand. 

The conclusion of Mr. Clarence King, that this island, which he examined, forms 
part of a terminal moraine of the continental ice-sheet, seems to explain the accumula- 
tion of the till in this remarkable series of hills. The border of the ice-sheet probably 
remained almost stationary through a long period, in which the materials that it con- 
tained were being continually brought forward and deposited at this line of its melting. 
In many places these would be pushed into very irregular heaps and ridges by retreats 
and advances of the ice-margin. At the same time we should also expect that thick 
beds of ground-moraine would be gathered beneath the ice near its termination. The 
withdrawal of the glacial sheet would then leave these deposits as upper and lower till, 
one overlying the other, in a long but broken and undulating series of hills. 

This terminal moraine does not, however, mark the farthest limit reached by the 
glacial sheet, which at one time extended six or seven miles beyond the Elizabeth 
islands, as shown by the prominent range of drift hills, which forms the north-west 
part of Martha’s Vineyard. The origin of Cape Cod also seems to have depended upon 
this greater extension of the ice-sheet. Its terminal front appears to have continued 
from Martha’s Vineyard north-easterly across Barnstable, thence to the east and north 
along the inner shore of the cape to Truro, which it probably crossed, extending on- 
ward to the north-east. This seems to be the outmost line at which we can assert the 
former presence of the continental ice-sheet. 

Cape Cod, east from Sandwich, consists almost entirely of modified drift. Through 
Barnstable this is disposed in kame-like ridges, knolls, and small plains, separated by 
crooked and bowl-shaped depressions. The material here is gravel and sand, often 
obliquely bedded, with frequent boulders which appear to have been dropped upon 
these stratified deposits from floating ice. From Barnstable to South Wellfleet the 
surface is mainly level, consisting of plains of fine gravel or sand, and boulders are 
rarely seen. These plains vary in height from 25 to 75 feet above the sea. From 
South Wellfleet to High Head in the north part of Truro, the contour on the west side 
of the cape is again in very irregular kames, which are composed of gravel and sand 
with only rare boulders. These deposits, like those in Barnstable, rise to a height 100 
to 150 feet above the sea. The east side of the cape is here a nearly continuous bluff 
of this height, horizontally stratified, being evidently a remnant of a nearly level plain, 
the east part of which has been washed away by the sea. Thick beds of clay have 
been exposed ata few points. At the Clay Pounds, near Highland light, the section 
is sand at the top, about 4o feet; finely laminated blue clay, also about 4o feet; then 


* Proceedings of the Boston Society of Natural History, vol. xix, pp. 59-63; and American Naturalist, 
vol. xi, pp. 674-680. 


GLACIAL DRIFT. 303 


sand, with occasional layers of gravel containing pebbles up to six inches in diameter, 
exposed for 20 feet, and probably extending as much farther to the sea-level. 

The accumulation of these thick deposits of modified drift, occupying an area more 
than forty miles long, with an average breadth of five miles, remote from any large 
river, and bordered on each side by the sea, seems capable of explanation only by sup- 
posing the material to have been held in an ice-sheet, which extended to the line that 
we have indicated, covering the Vineyard sound, Cape Cod and Massachusetts bays, 
and thence reaching to the north-east over a large part of the Gulf of Maine. When 
the return of a warmer climate drove back the front of these ice-fields to the long ter- 
minal moraine of the Elizabeth islands, Falmouth, Sandwich, and Plymouth, the rivers 
which flowed from their melting surface were principally discharged at two points, those 
at the south-west converging towards Barnstable, while those which descended from 
the glacial sheet over Massachusetts bay had their mouth in Wellfleet and Truro. The 
bordering walls and irregular masses and ridges of ice, which beset these rivers at their 
points of escape from the ice-sheet, caused their deposits over these areas to be massed 
in kames. The ocean at this period stood 150 feet or more above its present height; 
and the part of the burden of these glacial rivers, which was carried beyond their 
mouths, was spread by marine currents in nearly level plains, bordering the front of the 
ice-sheet. The true terminal moraine of till, formed by the ice at this bound of its 
greatest extent, is covered by the sea or by these beds of modified drift. 

The north end of these Champlain deposits is at High Head. The whole of Proy- 
incetown consists of sea-sand, with no pebbles. This sand has come from the erosion 
by the sea of the east shore of the cape; has been swept north and west to its present 
place in the lee of this breakwater ; lifted by the waves into beach-ridges ; and further 
raised by the wind into hills a hundred feet in height. 

On Long Island the farthest limit attained by the ice-sheet is probably indicated by 
a series of drift hills, which is commonly known as the «backbone of the island.” 
These hills are well exposed along the south shore for about ten miles west from Mon- 
tauk point, forming cliffs from 20 to 140 feet high. Westward, they extend through the 
north part of East Hampton, and from Sag Harbor south-west to the Shinnecock hills 
and Canoe place. Thence they continue in a nearly west course, including Osborn’s 
hill, a few miles south-west of Riverhead ; Terry’s hill, south of Manor ; Holman’s hill, 
north of Yaphank; the Coram, Seldon, and Bald hills; Mount Pleasant, west of Ron- 
konkoma lake; Pine hill; the Commac, Dix, and West hills; Spring, Wheatly, and 
Harbor hills, the last of which, near Roslyn, is the highest point on this island. Far- 
ther west, this series of hills trends a little more to the south, passing near Lakeville, 
and close north of Creedmoor, Jamaica, and East New York. Thence it nearly co- 
incides with the south-east boundary of Brooklyn, and reaches to the Narrows, forming 
the sites of Cypress Hill cemetery, Ridgewood reservoir, and the cemetery of the Ever- 
greens, of the highest portions of Prospect park and Greenwood cemetery, and of Fort 
Hamilton. 


The length of this range from Montauk point to the Narrows is about 115 miles. It 


304. SURFACE GEOLOGY. 


is interrupted at Neapeague beach and marsh, 12 miles west of Montauk point; between 
Manor and Yaphank; and at Syosset. West from Roslyn it is very plainly recognized 
as a continuous, irregularly undulating ridge. The heights of prominent hills in this 
series are as follows:* Montauk point, 85 feet above the sea; Fort Pond hill, five miles 
to the west, 194; Neapeague hill, 135; Amagansett hill, 161; Shinnecock hill, 140; 
Osborn’s hill, 293; Ruland’s hill, south of Coram, 340; Jane’s hill, the highest of the 
West hills, 354; Layton’s or Wheatly hill, 380; Westbury hill, 260; Harbor hill, 384; 
John M. Clark’s hill, near Manhasset, 326; Smith’s hill, 332; Prospect hill in Brook- 
lyn, 194. 

In the east and middle portions of the island the majority of these hills are composed 
of modified drift, being gravel and sand, distinctly stratified, and containing few or rare 
boulders. Osborn’s, Ruland’s, Jane’s, and Harbor hills are of this kind. They appear 
to be immense kame-like deposits, formed at the terminal front of the glacial sheet. 
As at Cape Cod, when this was obliged to retreat, its melting took place over a very 
wide extent of its surface; and the rivers thus formed were heavily freighted with 
gravel, sand, and clay, which had been contained in the ice. A large portion of this 
gravel and sand would be heaped at the mouths of these streams,—that is, at the 
points where they left these ice-fields and entered the lower open area beyond. 

The part of Long Island south of these hills consists of nearly level plains of fine 
gravel and sand five to ten miles in width, and extending a hundred miles in length. 
The height of their north portion at the foot of the hills varies from 50 to 150 feet 
above the sea. These deposits, like the levelly stratified drift of Cape Cod, appear to 
have been brought by the glacial rivers which formed the kame-like hills. The ocean 
rolled its waves above the surface of these plains, spreading the material which it thus 
received over a wide area to the south. 

Near the west end of Long Island this range of hills is composed entirely of unstrati- 
fied glacial drift, full of boulders, having all the characteristics of the upper till. It is 
well exhibited in the south-east part of Brooklyn by many excavations, as for cellars 
and streets. This is the true terminal moraine of the ice-sheet. Its continuation east- 
ward is for the most part covered by the later kame-like gravel and sand. Westward, 
this terminal moraine, principally composed of coarse, unstratified drift like the upper 
till, heaped in irregular hills and ridges, begins on the opposite side of the Narrows at 
Forts Tompkins and Wadsworth, crosses Staten island, and enters New Jersey} at 
Perth Amboy; it bends thence to the north-west and north, passing near Plainfield, 
Morristown, and Dover; next it runs west and south of west by Hackettstown to the 
Delaware river a little above Easton. 

The boundary of the ice-sheet at its period of greatest extent appears to be thus 


* From articles on the geology of Long Island, by Mr. Elias Lewis, Jr., of Brooklyn, in American Fournal f 
Science and Arts, third series, vol. xiii, pp. 235 and 236; and in Popular Science Monthly, vol. x, pp. 434-446. 
The greater part of these heights were determined by the United States Coast Survey. 

+The course of these hills at the most southern limit reached by glacial action in New Jersey is from the 
annual report for 1877, of Prof. George H. Cook, the state geologist. He says,—‘‘ The whole line of this mo- 
raine is remarkably plain and well defined.’’ 


GLACIAL DRIFT. 305 


plainly marked for a distance of three hundred miles, reaching from Truro, near the 
end of Cape Cod, through Barnstable, the north-west part of Martha’s Vineyard, Block 
Island, Montauk Point, the centre of Long Island, the south-east part of Staten Island, 
and northern New Jersey. Careful exploration will probably discover a similar series 
of hills, composed of unstratified upper till or of modified drift, at the border of the 
glaciated area through Pennsylvania, Ohio, and states farther west. 

A later terminal moraine seems to be indicated by the line of drift hills which forms 
the north shore of Long Island through the greater part of Brookhaven, Riverhead and 
Southold. Its extension to the east appears to be through Plumb and Fisher’s islands, 
and the southern edge of Rhode Island; thence to the Elizabeth islands, and from 
them northward to Manomet hill. At this line the ice-sheet made a long halt in its 
retreat. No similar series of drift deposits has been noticed farther north in New 
England, over which the melting of the ice-fields seems in general to have been with- 
out sufficient pauses for the formation of definite terminal moraines. 


It remains for us to inquire what was the origin, or mode of accumula- 
tion, of the lenticular hills and slopes of till which have been found to be 
abundant and prominent in many parts of southern New Hampshire. We 
have seen that in Cheshire, Hillsborough, and Rockingham counties these 
lenticular masses are scattered here and there, and in some places quite 
thickly, upon three areas which vary from five to twenty miles in width, 
and extend twenty-five or thirty miles from north to south, or from north- 
east to south-west. The greater part of the most eastern of these areas 
lies beyond the state line in Essex county, Mass. These tracts are sepa- 
rated by others of equal or greater width, upon which scarcely any len- 
ticular hills are found. This territorial division in three groups does not 
appear to have been caused by differences in the adjacent stratified rocks; 
it more probably resulted in some unexplained way from movements of 
the ice-sheet. It is the only indication of system which we have discov- 
ered in the distribution of these hills. Whether they occur rarely or very 
abundantly, they are alike irregularly scattered without any apparent 
order or connection, nowhere forming well defined series, like those of 
the terminal moraines of Plymouth and Barnstable counties in Massa- 
chusetts, and of Long Island and New Jersey. 

In Sullivan, Carroll, Belknap, Merrimack, and Strafford counties, len- 
ticular accumulations of till are sprinkled more sparingly, with no traces 
of system, being numerous in some localities, but generally rare or ab- 
sent. With this diminution in numbers northward, the relative propor- 


306 SURFACE GEOLOGY. 


tion of lenticular slopes of glacial drift resting against ledgy hills is 
increased. Carroll county is especially remarkable for the frequent oc- 
currence of these slopes on the north-west side of hills, directly facing 
the powerful current of the ice. 

Nearly the whole of New Hampshire presents a very uneven surface, 
consisting of broken and irregularly grouped hills and mountains. The 
distribution of the lenticular hills does not seem, however, to depend 
upon these features. They are very finely developed on the lowland near 
the coast, but not less so in Dublin, Jaffrey, and Rindge, upon the height 
of land between Merrimack and Connecticut rivers. Beside the coast 
they are spread over an area which would otherwise be nearly level ; at 
many places inland they are equally abundant among high, irregular hills. 
They seem as likely to be found upon one side as another of any moun- 
tain or prominent hill-range. The altitude at which they occur varies 
from the level of the sea to 1,500 feet above it. By reference to a map 
in the atlas, the relation of the lenticular hills to contour lines and strize 
will be readily seen. 

The most noticeable feature of these remarkable deposits is their 
smoothed oval form with a definite trend or longer axis, which lies 
almost invariably in the same direction with the striae. Thus their 
position is the one which opposed the least resistance to the glacial 
current, and is that which would be assumed by accumulations formed 
beneath the moving ice-sheet. Deflection in the trend of these hills 
at any locality from their prevailing course over adjacent areas is usually 
accompanied by deflected striz. An instance of this occurs in Dublin 
on the north side of Monadnock mountain, where both lenticular hills 
and striz point thirty or forty degrees more than usual to the east of 
south. A similar deviation of the striae has been noted at Andover and 
Potter Place, on the north side of Mt. Kearsarge, but no lenticular hills 
occur there. It would appear that any isolated mountain like these, 
while enveloped in the ice-sheet, might cause only slight variation in its 
current, which must overcome as great resistance in turning aside as in 
passing upward without changing its course; but near the end of the 
glacial period, when such barriers were reached by the retreating termi- 
nal front of the ice, its current from the north would no longer be 
pushed upward by the continuous glacial sheet, so as to pass over the 


GLACIAL DRIFT. 307 


mountain, but would be deflected toward the vacant area at the south- 
east. It seems probable, therefore, that the hills mentioned were 
moulded with their unusual trend during the decline and departure of 
the ice-sheet, Such deflection of the lenticular hills is uncommon, their 
trend being nearly uniform over large areas, gradually changing from a 
south-east course in Carroll, Strafford, and Rockingham counties, to a 
nearly south course in the west part of the state. 

The till of Scotland is described by Mr. James Geikie,* as massed in 
ridges which seem to be somewhat like our lenticular hills, but more 
prolonged and less prominent. His opinion that these accumulations of 
the Scottish till were formed beneath the ice-sheet, seems to be true also 
of the lenticular hills and slopes of New England. The reasons which 
lead us to this conclusion are the distance of these deposits from the 
end or outside limit of the ice-sheet, as it probably existed through the 
greater part of the glacial period; their difference from the hills and 
ridges of the terminal moraines there formed; the trend of the lenticu- 
lar accumulations ; their composition principally of lower till; the occur- 
rence in this till of level sandy layers; the similarity of the lenticular 
hills to slopes which rest against ledgy hills, either upon the side which 
was sheltered from the ice-current or upon that which was fully exposed 
to it; and the obscure lamination, which may be commonly observed in 
sections of the lower till, whether in lenticular masses or in flattened 
sheets. 

Below a thin covering of upper till, the material of which the inner 
portion of these hills and slopes is formed is the dark and compact lower 
till, which has been described on pages g and 286. It has been shown 
that the character of this deposit can be explained only by supposing it 
to be the ground-moraine accumulated beneath the moving ice-sheet. 
The small proportion of its iron that has become fully oxidized, and the 


* In the Lowlands the effect produced by the varying direction and unequal pressure of the ice-sheet is 
visible in the peculiar outline assumed by the till. Sometimes it forms a confused aggregate of softly swell- 
ing mounds and hummocks; in other places it gives rise to a series of long smoothly-rounded banks or ‘ drums’ 
and ‘sowbacks,’ which run parallel to the direction taken by the ice. This peculiar configuration of the till, 
although doubtless modified to some extent by rain and streams, yet was no doubt assumed under the ice-sheet.’? 
—The Great Ice Age, American edition, p. 88; second edition, revised, p. 76. 

This explanation is quite different from that advanced by Prof. N.S. Shaler, respecting the lenticular hills of 
eastern M. h ts, in the Pr dings of the Boston Society of Natural History, vol. xiii, pp. 196-203. 
He supposed these hills in the vicinity of Boston to be remnants spared by the fluviatile and tidal erosion of a 
once continuous sheet of drift, which had been contained in a glacier that descended the Charles River valley 
and was deposited at its melting. 


308 SURFACE GEOLOGY. 


very fine clayey detritus in which its glaciated pebbles and boulders are 
embedded, indicate that this portion of the drift has been mostly derived 
by erosion from the rocks, and pulverized under the grinding action of 
the ice-current. 

The level layers of gravel, sand, or clay that are occasionally found in 
this lower till appear to have been formed by streams, which in summer 
found their way through crevasses to the bottom of the ice. These 
seams and beds of modified drift in the till frequently occur upon len- 
ticular hills and slopes, where they could not have been deposited by 
ordinary streams, if the ice-sheet was withdrawn. The usually horizon- 
tal position and considerable extent of these beds show that after their 
formation they lay undisturbed, while the ground-moraine continued to 
be deposited above them. Where similar seams or beds are nearly ver- 
tical, inclined, or contorted, as they are more rarely observed, it shows 
that a large mass of the lower till was lifted up before the ice-current, 
and pushed forward with its included layers of modified drift. 

The accumulation of these hills and slopes seems to have been by slow 
and long continued addition of material to their surface, the mass remain- 
ing nearly stationary from the beginning of its deposition. Obviously 
this was the case with the lenticular slopes gathered behind the shelter 
of higher ledgy hills, or upon their opposite sides. Except in their loca- 
tion, these slopes are like the lenticular hill, which seem to contain no 
ledge, being simply heaps of the ground-moraine 50 to 200 feet in height. 
This resemblance suggests that both hills and slopes alike increased 
slowly in extent and depth without much change in place, new material 
being lodged upon their surface from the ice-sheet which swept over 
them. 

The obscure lamination or cleavage, which is one of the characteristic 
features of the lower till, was probably produced by this mode of its ac- 
cumulation. In this deposit from the ice-sheet, it corresponds to the 
stratification of sediments from water, but it is less distinct; and the fine 
detritus in which it appears contains glaciated pebbles and boulders in- 
discriminately mixed through its whole mass. This structure was at first 
thought to be a true cleavage, caused by the pressure of the glacial 
sheet. If we take this explanation, it still proves, like the hardness and 
compactness which also mark the lower till, that this deposit was not 


GLACIAL DRIFT. 309 


ploughed up by the enormous pressure of the ice passing over it. How 
could this force permit the ground-moraine to be heaped in the steeply- 
projecting lenticular hills? Instead of this we should expect it to be 
left only in flattened sheets or behind sheltering ledges. The probable 
answer seems to be, that the finely pulverized detritus and glaciated 
stones in the bottom of the ice-sheet had a tendency to lodge upon the 
surface of any deposit of the same material, When such banks of the 
lower till became prominent obstacles to the ice-current, its levelling’ 
force was less powerful than this tendency of adhesion, which continually 
gathered new material, building up these massive rounded hills. At 
the melting of the overlying ice-sheet, the surface of hills and valleys, 
ground-moraine and ledges, were alike covered by the nearly continuous 
mantle of the upper till. Ww. U. 


NOTE UPON LENTICULAR HILLs, By C. H. HITCHCOCK. 


Thorough search for these moraines has been made in all parts of the state south of 
the White Mountains, not including Grafton county. Not many more will be added 
by future observations. I do not think any occur in Grafton county. In Canaan, long 
drift covered hills south of the centre bear some resemblance to them. A trip through 
eastern Vermont revealed facts of interest. In Orange two hills in the south-west 
corner resemble lenticulars, and, as seen from a distance, there appear to be genuine 
examples on the north-west side of the church. In Peacham and Danville, num- 
erous rounded hills resembling these moraines may be seen from elevated positions. 
Some that I examined proved to be composed of limestone, weathered roundish; so 
it seems probable that all the others are similarly constituted. One not familiar with 
the behavior of this rock, when acted upon by atmospheric agencies, might call all 
these mounds lenticular hills. Large drift hills are known to occur in Bethlehem and 
Whitefield. Another trip to the localities would be requisite to enable me to pro- 
nounce upon their existence in these towns or elsewhere in Coos county. It seems 
probable that the great drift hill just west of Chocorua pond in Tamworth should be 
of this character. The heliotype illustration of some of these hills in Goffstown ad- 
mirably represents their general character. All the hills in the view are true lenticular 
ground-moraines, with no ledges inthem. They are simply piles of earth and stones 
accumulated beneath the ice-sheet, and afterwards covered by the upper till. The 
information contained in Mr. Upham’s description of these hills is one of the most 
valuable contributions to science obtained during our whole survey of the state. 

VOL. III, 40 


310 SURFACE GEOLOGY. 


LakE RAMPARTS. 


Under this name I have described in earlier state reports ridges of 
boulders and coarse gravel bordering certain portions of shallow ponds. 
They occur where the water is not deep, and there is a considerable 
exposure of shoal bottom strown with boulders. As the water freezes in 
the winter the ice encloses these stones, and by virtue of expansion 
moves them nearer the shore. The amount of pushing in a single sea- 
son would be small; but the work would be resumed every winter, and 
in the course of ages the fragments would reach the shore, and perhaps 
be crowded inland. Farmers who build fences on the edges of a wide 
ditch often find them bent or prostrated in the spring for a similar rea- 
son; the expansion of the water in freezing has pushed them over. 

Several instances of these ridges have been observed in New Hamp- 
shire. The best known is on the Vaughan shore in Moultonborough, in 
the north-east part of Lake Winnipiseogee. We find there a ridge one 
eighth of a mile long, opposite a broad expanse of shallow water about 
four feet in height. Passing easterly 125 feet, the ground is low and 
swampy, and another similar ridge about fifteen feet high is encountered, 
fronting a low terrace. It is very likely this ridge represents an older 
rampart, made when the lake stood at a higher level. The shore and 
the ridges are covered by shrubs and trees. A pine had been cut re- 
cently from the smaller rampart, whose trunk has a diameter of twenty- 
eight inches. From this I obtained a section for the museum, and 
counted 122 rings of growth upon it. As this had been cut twenty-five 
years Bee to my visit (1871), it is obvious that certainly a century 
has elapsed since the formation of the rampart. I saw 
a tree still standing upon this ridge twenty-seven inches 
A few years since, in the case of the town 
SES of Gilford v. The Winnipi- 
1 seogee Lake Company, it 


in diameter. 


was found expedient to use 

Fig. 62.—LaKE RAMPART, MOULTONBOROUGH. tn facts shown by this ram- 
part with the trees upon it, to prove that there had been no unusual 
flowage of the lake for the past hundred years. The whole court ad- 
journed to visit the locality. Fig. 62 shows the two ramparts with a tree 


GLACIAL DRIFT. 311 


standing upon the first. Another example may be seen at the south 
end of Long island. It is possible that Steamboat island and its cul- 
mination south in a ridge in shallow water is to be regarded as one of 


these ramparts. 
Sea WALLS. 


A variety of the sea-beach action is indicated by the term sea walls, 
which I suggested for them in 1861.* It is along embankment of smooth 
boulders, without sand or gravel, lying just behind the beaches. When 
the more powerful storms prevail off the coast, stones up to two feet 
in diameter are carried a distance of hundreds of feet, and deposited just 
back of the beaches. Sometimes they are fifteen feet in height. I have. 
noticed them in Rye. 


DisTURBANCES IN MopIFIED DRIFT. 


A few examples of curvature in layers of gravel and sand have been 
noticed. One of them is represented in Fig. 63. It is seen on the east 


Fig. 63.—SECTION IN GRAVEL, WHITEFIELD. 


side of John’s river, in Whitefield, just east of the depot. Coarse gravel 
occupies the centre and lowest part of the arch, and there is another 


mass of it upon the steep slope to the left. The bank was exposed for 
about fifteen feet. 


* Preliminary Report Geology of Maine, p. 270. 


312 SURFACE GEOLOGY. 


Another style of disturbance is indicated in faults, some of which have 
been referred to upon page 39. Many of them can be regarded as the 
result of local sliding. One more difficult to explain may be seen be- 
tween Mink brook and the village of Hanover upon the West Lebanon 
road. The first bank next the brook, below Mr. Benton’s house, dips 10° 
northerly. Near the base of the principal hill, north of Benton’s, the 
dip is southerly at the same angle. Near the top the stratification is 
horizontal. The section along the road shows the loamy sand to have 
a synclinal structure, or, rather, there are two faulted segments dipping 
towards each other. Other highly inclined masses of alluvium occur 
close by the railroad depot in Norwich, at the north edge of the great 
plain two miles from Dartmouth college on the Lyme road, and near the 
mouth of Grant brook in Lyme, where the angle of inclination amounts 
to thirty degrees. It seems likely that the forces disturbing these ter- 
races were analogous to the elevating agencies that displayed their power 
in the earlier periods of geological time. Earthquakes of greater severity 
than are now common in the state might have been adequate to produce 
the results. The facts are given to draw the attention of other and future 
observers to the subject, as they may find more important illustrations of 
a continental force, or else discover satisfactory evidence that the dis- 
turbances have been entirely due to gravity. 


Ick AccCUMULATIONS. 


Occasionally the conditions are favorable for the continuation of ice 
unmelted through the entire summer. The best known example is in 
Tuckerman’s ravine, described in Volume I, page 623. Here it is ex- 
posed to the sun and air, continuing very long because of an immense 
accumulation. In other cases the ice is preserved in caverns, or in the 
midst of large fragments of rock, as in Lyman, Effingham, and Plymouth. 

In Lyman, about half a mile west of Parker hill, ice accummulates 
beneath large stone fragments at the base of a cliff. I found no ice there 
September 4, 1870, though the air issuing from the side was very cold, 
indicating its existence. The people in the neighborhood often obtain 
ice from this locality in the summer. In a journal published in Concord 
in 1823, it is related by Caleb Emery, of Lyman, that in 1816, a mem- 
orable cold summer, he saw a well frozen over solid, eight feet from the 


GLACIAL DRIFT. 313 


surface, in June. The ice had to be cut to enable the draught of water. 
In July, he found a mass of ice floating in this well as large as a wash- 
tub. 

In Plymouth, there is said to be an ice-cave in the west part of the 
town, where ice can be obtained every summer as late as the month of 
August. 

Upon the north slope of Green mountain in Effingham I found large 
masses of ice in the latter part of August, 1875. Near the edge of a 
precipice enormous blocks have been separated from the ledges, making 
large passages like caves, where different fragments rest upon each other 
like arches. On descending twenty feet I found ice, and then followed 
along forty feet to a much larger opening. This ice-cellar is well known 
to the people living in the neighborhood. 

A study of similar ice-masses elsewhere shows the existence of cur- 
rents of air, downward in the summer and upward in the winter, which 
evaporate the water, and, by the accompanying removal of heat, induce 
cold sufficient to freeze water and to preserve the ice thus formed. The 
principle has been made use of in warm countries to produce ice artifi- 
cially in merchantable quantities. 


BEAVER Dams. 


Several bogs in the state owe their existence to the former presence 
of the dams made by beaver. This animal is now entirely extinct, owing 
to the advance of clearings and the removal of the forests. It is not 
uncommon to find sticks that have been gnawed by these creatures. 
One such example is in Plainfield, where they occur underneath pine 
trees more than a foot in diameter. It is plain that here a bog was 
filled up by the natural accumulation of sediment in the beaver pond, 
and the land became dry enough for pines to grow. The name of 
“beaver meadow” is frequently heard throughout the state, and indi- 
cates the prevalence of bogs reclaimed by animal agency. One of the 
largest of these lies between Mts. Misery and Odiorne, in Weare, on the 
land of Hon. Moses Hodgdon, nearly a mile in length. It is-used for 
grass, and in wet seasons is often flooded with water. Logs occur quite 
deep down, in a soft mud in which poles can be thrust for several feet. 


314 SURFACE GEOLOGY. 


Nortu AMERICA IN THE IcE PERIOD. 


Candid geologists admit that no part of their knowledge is so obscure 
as that of the cause of glacial cold. Various theories have been sug- 
gested to account for it, but none of them command universal accept- 
ance. Before it can be properly answered, we shall find it necessary 
to consider somewhat the conditions of glacial envelopment, the dimen- 
sions of the areas occupied by the ice, and the directions in which move- 
ment has been effected. In such a study we shall find it necessary to 
look far beyond the confines of New England, for the movements in this 
comparatively limited area are unlike those occupying the greater part 
of the continental ice-sheet. Some of the difficulties we have expe- 
rienced in generalizing our observations result from the smallness of 
our field of study. I will therefore present upon a small map of the 
north-east portion of our continent a delineation of the areas occupied 
by the ice in its period of maximum development, with arrows to indi- 
cate the principal directions of movements. An examination of this 
map, with a brief description of the principal features of glaciation may 
furnish the means for satisfactory generalizations respecting the origin, 
extent, movements, and duration of the ice-sheet. 

The Alps of southern Europe furnish the most accessible example of 
glaciers in action, with indications of greater extent in the ice-period. 
The higher portions of the range are occupied by immense fields of 
snow, which are the source of the numerous glaciers pushing out from it 
on every side, both towards Switzerland and France on the north, and 
towards Italy upon the south. These glaciers may be said to radiate 
from a central line of dispersion. In the Alpine district the accessible 
glaciers behave like streams of water, occupying only the bottoms of the 
valleys, and descending to the lower levels apparently in obedience to 
the laws of gravity. A study of the former extent of these glaciers indi- 
cates their former extension across the valley of Switzerland to the Jura 
mountains. The Rhone glacier moved over the great valley to the Jura 
mountains, occupying an area 50 miles wide, 150 long, and 2,000 feet 
deep. Lateral, medial, terminal, and ground moraines occur in connec- 
tion with all these glaciers, Large boulders have been transported from 
Mt. Blanc to the Jura. 


GLACIAL DRIFT. 315 


An example more nearly analogous to our own is afforded by the former 
extension of the Scandinavian glaciers. Erdmann’s map represents striae 
pushing northerly into the Arctic ocean ; south-easterly, in the promon- 
tory between the gulfs of Finland and Bothnia; south-east and south, 
varying west of south, also, in the lower part of Sweden; west, north- 
west, and south-west, in Norway towards the Atlantic ocean. Croll sup- 
plements this map, by showing the continuation of the southerly course 
into Prussia; a bending of the direction to conform with the Baltic sea, 
passing over Denmark to both the south and north of England. Scot- 
land and England are made to send off additional ice-currents; and the 
western edge of the ice-sheet reaches to west longitude 14°, or as far as 
the seaward limit of comparatively shallow water. This area is certainly 
1,700 miles wide, and 1,500 from north to south. This will compare 
favorably in size with our American glaciated area. The latest author- 
ities show that the phenomena are all explicable by the existence of a 
principal central ridge of dispersion in Scandinavia and subordinate ones 
in Great Britain; also, that there is no evidence of the flow of ice from 
the polar regions into northern Europe. There exists, therefore, a close 
analogy between the glacial conditions of Scandinavia and North Amer- 
ica ;—and if the former can be explained upon the theory of a centre of 
dispersion, so can the latter. 

Before considering the location of the American centre of dispersion, 
it will be well to recall the glacial conditions existing at the present time 
in Greenland, since they will illustrate the state of things in New Eng- 
land during the period of the greatest cold. We discover there how the 
ice can move up hill, and how the ground moraine can be formed. 


GLACIERS IN GREENLAND. 


Greenland was discovered by Gunnibiorn in 872, In 983, Eric the 
Red, banished from Iceland, established a colony near the south end of 
Greenland, imposing upon it the name it now bears. The settlement 
prospered; and indications of civilization left behind by these Norsemen 
exist as far north as Upernavik (latitude 72° 50’), or as far north as the 
stoutest ships of modern times can sail without encountering serious 
risk, The population increased sufficiently to require the services of a 
bishop; and a list of seventeen of them, from 1126 to 1406, has been 


316 SURFACE GEOLOGY. 


preserved. A change of political relations led to the destruction of the . 
commerce between Greenland and Scandinavia, and, followed by attacks 
of pirates, and the Skraellings or Esquimaux, led to the complete exter- 
mination of the Norse colony. The history of the last man has been 
preserved in Icelandic annals, whose death occurred early in the fifteenth 
century. Europe has been in doubt respecting the fate of this colony 
ever since, it having been claimed very recently that it was established 
on the eastern coast, and that the descendants of the original settlers 
might still be found there, shut off from the rest of the world by ice 
that had increased in amount since the last ship had communicated 
with them. The name Zas¢ Greenland has led to confusion, since it 
might be interpreted to signify the coast looking towards Iceland instead 
. of Baffin’s bay. The most southern of the settlements upon the south- 
west coast was east of the others, and hence the use of the term East 
Greenland. The ruins of ancient churches and monuments found on 
the south-west coast clearly confirm the truth of the Icelandic sagas. 
The island is almost continental in dimensions (perhaps consisting of 
an archipelago), being over 1,200 miles long and 400 broad, as far as 
from Boston to the mouth of the Rio Grande, or to Utah. The interior 
is covered by a field of ice, never entirely traversed by any human being. 
From three points attempts have been made to learn something of its 
nature. In 1830, Keilsen went 80 miles inland from Holsteinberg (lati- 
tude 67°), reaching the edge of the ice-sheet, which could not be climbed. 
Nordenskiold, in 1870, went in 30 miles, reaching the altitude of 2,200 
feet. He observed that the ice rose gradually towards the interior. The 
outer edge is a high wall. Once entered upon the broad surface of the 
ice, it is like travelling upon the sea, away from all sight of land. From 
North Greenland Dr. Hayes penetrated to a distance of 70 miles. It 
was a day’s journey to the wall from the sea. The second day was spent 
in climbing to the table-land; the third day allowed a progress of thirty 
miles, the angle of ascent falling from 6° to 2°. On the fourth day an 
ascent of 5,000 feet was reached, not the highest point,—but the weather 
became too inclement to permit a longer stay. The view was that of a 
frozen Sahara, immeasurable to the human eye. 
It is probable that Greenland slopes westerly in general, thus placing 
the highest ice-ridge near the eastern border; for there are very few ice- 


GLACIAL DRIFT. 317 


bergs off theyeastern coast, such as would be seen if the glaciers dis- 
charged themselves as they do upon the western side. At the rate of 
increase indicated by the observations of Hayes, the height of land may 
be averaged at 5,000 feet, and the thickness of ice above it as 10,000 feet. 
This flows mainly into Baffin’s bay, Smith’s sound, and the other waters 
to the west. A northward transportation is indicated at Polaris bay, 
where Dr. Bessel found numerous granitic rocks containing peculiar 
garnets, such as abound in South Greenland, resting upon Silurian lime- 
stones. On the western side are no less than thirteen well marked gla- 
ciers discharging their bergs into the sea, as far north as Upernavik, 
about 73° north latitude. The largest ones occur further north, some of 
them being 3,000 feet thick. The bergs derived from them are of this 
thickness, as measured by Hayes. The Humboldt glacier enters Smith’s 
sound with a width of 60 miles, the ice-cliffs, from 50 to 300 feet high, 
extending 2,000 feet deep in some places. The adjacent rock-cliffs are 
500 to 1,000 feet high. 

The derivation of icebergs from glaciers is well proved. The glacier 
pushes down the fidrds into the sea, till the buoyancy of the ice, lifted up 
by the waters, causes it to separate in large blocks which float out to sea, 
urged onwards by the land motion, and afterwards by the oceanic cur- 
rents. Baffin’s bay and Davis straits are filled with these bergs, which 
float southerly till the warmer air and water of the lower latitudes dis- 
solve them. It is uncommon to see them as far south as 40° north lati- 
tude. The romantic history of Tyson’s party illustrates the long con- 
tinuance of floating ice. This party consisted of nineteen persons, and 
they floated southwards 1,800 miles in six months’ time, before they were 
rescued,—October 16 to May 1. 

These bergs often carry earth and rocks in immense amount. Scoresby 
saw some carrying from 50 to 100,000 tons of material. Every Arctic 
traveller describes them. This rubbish falls to the bottom as fast as the 
bergs melt or topple over. It has been suggested that much of the 
Great Banks of Newfoundland has been accumulated from the leavings 
of icebergs. 

Greenland may be compared to a broad platter slightly inclined west- 
erly, with occasional chinks in the sides through which the ice discharges 


itself, as if it were a viscous body. We might say the ice accumulates 
VOL. III. 41 


318 SURFACE GEOLOGY. 


in immense amount till it makes a conical pile like a heap of grain upon 
a floor. When additions are made to the grain upon one side, a motion 
is induced, and more of the kernels will flow down on that side than 
were added, because of cohesion. If the floor be slightly inclined, the 
flow of grain would be greatly facilitated. In a similar manner we may 
believe the flow of ice down certain valleys will carry with it other parts 
of the ice sheet, even where much of it is dragged over hills. This rise 
would always be less than the amount of descent from the top of the ice 
accumulation. With the ice would be carried the blocks of stone im- 
bedded in it through the pressure of the weight of the overlying mass. 
Except near the coast, none of the Greenland ice would show boulders 
upon the surface, because, unlike the Alpine mer de glace, the mountains 
are entirely covered, and no moraines could be accumulated by the fall- 
ing down of fragments from the hillsides. The moraines of Greenland 
are therefore different from the ordinary heaps displayed on the sides, 
tops, and ends of Swiss glaciers; they must accumulate mainly beneath 
the ice-sheet, and not be visible so long as the ice remains unmelted. 
The finer parts and the favorably situated blocks would, however, be car- 
ried along with the glacier to some extent, to be distributed eventually 
as submarine deposits, or to become a species of residual moraine after 
the melting. 

Further peculiarities of distribution appear in connection with the sub- 
glacial streams. From the ends of the glaciers issue muddy torrents 
derived from the melting of the ice. Immense supplies of heat pene- 
trate the ice from the sun’s rays, which must give rise to very much 
water, seen also in the numerous surface lakes and streams. As all 
water seeks the lowest levels attainable, these currents will find a place 
at the bottom of the ice-sheet, and wear away the rocks and ground- 
moraines already accumulated into the sea. Hence will arise banks of 
earth or clay more or less continuous from the ice cliff to the point 
where the current ceases to transport material. In these banks would 
be found remains of such marine animals as lived in the vicinity. These 
deposits remind us of the fossiliferous clays along the coast of New Eng- 
land, sometimes attaining an altitude of 150 feet. Boulders would occur 
in this clay, brought by bergs, so that it might be styled boulder clay. 
This deposit is analogous to that called the Champlain clays. 


GLACIAL DRIFT. 319 


Evidence has been often stated showing that the south end of Green- 
land, for a space of 600 miles, is sinking, and the north end rising. 
Tyson and Bessel speak of marine shells found 1700-2000 feet above 
the sea level near Polaris bay. If there were shoal water between 
Greenland and Labrador, the glaciers would push across to the main land 
of the American continent. 


Tue AMERICAN CENTRE OF DISPERSION. 


It seems probable from the latest grouping of facts that some part of 
the Labrador peninsula may be considered as the centre from which the 
ice west and south-west from Greenland has radiated. Greenland may 
be regarded as an area by itself, never confluent necessarily with the 
Labrador or principal American ice-sheet. The various facts in support 
of this view will now be stated. 

The greatest amount of glaciated territory indicates a south-westward 
course. This is seen over the highlands between Hudson’s bay and the 
St. Lawrence valley, the valley itself, western New York, Ohio, and so 
on to the extreme west edge of the drift. It is very prominent from the 
Lake of the Woods and Lake Superior, near the national boundary to 
the Rocky Mountains. In New England the dominant course is south- 
easterly, with both south and west of south directions. The same is 
true of New Brunswick and Nova Scotia. Accounts differ for New- 
foundland. J. F. Campbell’s observations indicate greater variation, 
possibly a radiation in every direction. Murray’s observations are said 
to show a south-westerly course, but a recorded observation from him is 
about S. 30° E. On the east coast of Labrador the map shows several 
fiords, as if there had been an ice-sheet upon the upper part of the 
peninsula moving north-east and east. Hind finds glacial markings on 
the Moisie river, and notes a remarkable absence of boulders up to 1,000 
feet in height. He does not state in what direction the ice moved. Prof. 
O. M. Lieber’s sketches in the coast survey report do not suggest uni- 
versal, but local glaciation, as if the ice came from the peninsula itself, 
not from Greenland. Packard describes glacial markings in the Hamil- 
ial inlet fisrd running to the north-east. On the southern shore, Packard 
thinks the movement was to the south-east, towards N. ewfoundland. 

Farther north, the Meta incognita just north of Hudson’s straits shows 


320 SURFACE GEOLOGY. 


an extensive mer de glace with glaciers moving southerly, and, most 
likely, northerly also. McClintock describes boulders at Leopold har- 
bor (North Somerset), and at Graham Moore bay (Bathurst island), 
which have been transported 100 and 190 miles north-east and north- 
west. West of Hudson’s bay, all explorers describe glaciated conditions, 
but give scarcely any data to enable us to learn the direction of the move- 
ment. In Franklin’s first voyage (1819-22), loose stones are described, 
whose “angular forms” militate against their having travelled great dis- 
tances. In his second voyage are quite a number of notices, implying 
transportation in a westerly direction. 

There is a marked difference in the distances to which boulders have 
been transported by the south-west and south-east currents. The latter, 
as indicated heretofore, are not known to have travelled as much as 100 
miles. The average distance may not exceed 12 to 15 miles, and there 
are no boulders in New Hampshire that have come from the north side 
of the St. Lawrence, nor from great distances in Maine on the north- 
east. In Ohio many have come from more than 100 miles. Boulders of 
native copper in Iowa and Wisconsin have travelled from 300 to 465 
miles. The greatest transportation in the north-west region has been 
that of boulders from the Lake of the Woods, 7oo miles towards the 
Rocky Mountains, upon British territory. Transportation upon ice-floes 
or bergs has been greater, as from Canada West to Baton Rouge, La. ; 
but the others were mostly ice-carried. The greater south-west trans- 
portation seems to be connected with topographical features, viz., the 
continuation of this St. Lawrence valley to the south-west and south. 

The distance of observed continuous south-westerly striation from the 
Laurentian highlands to the base of the Rocky Mountains is about 1500 
miles. From central Greenland to the same place it exceeds 2500 miles. 
We have the means for determining approximately the thickness of the 
ice-sheet requisite to cause a flowage. It would require an average 
slope of about one half of a degree to make the ice move reasonably 
fast. This is forty-six feet to the mile, or one foot rise in every 115 
feet of distance, or one mile for every 115. These data would necessi- 
tate an ice-cap 13 miles high if the centre of dispersion were in Labra- 
dor, or 22 miles for the whole distance to central Greenland. Making 
use simply of what would be required to move the ice over New Eng- 


GLACIAL DRIFT. 321 


land, we find that 800 miles represents the distance to central Labrador, 
requiring a cap 7 miles higher than Mt. Washington, or over 8 miles thick 
in all. If the movement came from Greenland, the distance is estimated 
at 2,000 miles, and the elevation of the ice-cap at 17 miles above Mt. 
Washington Prof. Dana, from somewhat different data, obtains smaller 
results. Assuming the starting-point to have been on the height of land 
between the St. Lawrence and Hudson’s bay, and the descent at 15 feet 
per mile, the sheet must have been at least 13,000 feet thick above the 
land to carry it over Mt. Washington. These figures sound less formid- 
able, but the slope does not seem adequate to have produced the results. 
Prof. Torell, of Sweden, read a paper before the American Association 
for the Advancement of Science, in 1876, advocating the source of the 
American drift to have been in Greenland. He writes thus: * 


It has been the opinion of many distinguished American geologists that the source 
of the eastern ice fields is to be sought in the Canadian highlands. Against this opin- 
ion several important reasons may be urged. First: in the portions of Canada in 
which the glaciers in question are supposed to have originated we have reason to be- 
lieve that the rocks are rounded and scratched, phenomena everywhere recognized as 
glacial,—but I think in no case characterizing rocks known to have been covered with 
perpetual snow. Again: the elevation and extent of the highest portions of Canada 
are hardly sufficient to account for the requisite accumulation of snow and ice. And 
finally, so far as I have learned, there is not found upon the rocks of the northern 
slope of Canada, nor yet in boulders moved by glacial force, any satisfactory evidence 
that there had been a northward as well as southward movement of glaciers from the 
highlands of Canada. If, therefore, the phenomena of the northern and eastern 
United States, usually supposed to be glacial, are indeed such, and if there is not suffi- 
cient reason for assuming the Canadian highlands to have been the source of the 
glaciers which produced these phenomena, then the source of them must be sought for 
elsewhere. 

I think it will be conceded by all geologists who have studied the glacial phenom- 
ena of these regions, that both the character of the erratics and the direction of the 
scratches upon the rocks show that this source must lie to the north-east. Following 
the line of the glacial movement across Baffin’s bay and Davis straits to Greenland, 
we find the largest body of land in the northern hemisphere covered by ice and snow 
to a depth of not less than 2000 feet, and at this moment sending down its icebergs as 
far as the middle Atlantic. From the sixtieth degree of latitude to above the eightieth, 
this vast area of land is known to be ice-covered, and from the scarcity of the icebergs 
upon the eastern compared with the western coast of that land, it may be concluded 


* American Yournal of Science, iii, vol. xiii, p. 78. 


322 SURFACE GEOLOGY. 


that the general slope of the land is to the south-west, and in exact direction of the 
glacial markings of what is known to have been the course of the transported boulders 
in north-western America. Moreover, if we bear in mind the certainty that during the 
glacial period the glaciers moving from the height of Greenland towards the sea could 
not have formed detached icebergs as now, but must have for the time blocked up all 
avenues except the one of easiest escape for the immense accumulations of ice, we 
may easily assume this avenue was south-westward across British America and the 
north-eastern part of the United States. 


Prof. Dana accepts this theory, saying that “we [self and Torell] agree 
in all essential points.” A few suggestions have occurred to me, to the 
effect that the Greenland theory is untenable. (1) Accepting the notion 
that the ice moves as Croll proposes, on the molecular theory, there must 
be a piling up of ice to an enormous thickness, as much as twenty-two 
miles, to account for a motion from Greenland to the extreme south- 
west known limit of the ice-sheet. (2) The bridging of Davis straits 
seems very difficult to explain. The water is deep, and the straits or bay 
(Baffin’s) wide, sufficiently so, it would seem, to discharge all the glacial 
products poured into it from either side. (3) Good instances of a north- 
ward transportation have been mentioned, the best known being north- 
ward from Hudson’s bay. The great lack of observations of such a 
nature everywhere to the north of the Laurentian water-shed renders 
affirmation of their presence or absence valueless. Some have said that, 
on account of the cold, there would be little motion northerly. (4) The 
Labrador peninsula seems to me to offer a good situation for the accum- 
ulation of an ice-cap large enough to account for all the phenomena. The 
fidrds on the east indicate north-east movements of the ice; and three 
other courses have been mentioned, so that we find good evidence of 
motion in four directions from the central table land. Supposing this a 
centre, Greenland would have been a second, of equal or greater height, 
and the two would discharge their surplusage into the Atlantic. A cap 
of thirteen miles would be required for the thickness of this ice, if there 
were a flow from it to the western edges of the plains. (5) The growth 
of Greenland and the neighboring parts of the continent suggests the 
origin of the great basins, as of Baffin’s bay, in Eozoic times, and a prob- 
able submergence ever since. The Hudson’s Bay depression is similar 
(see Fig. 1, Vol. II). The Miocene deposits of Baffin’s bay were made 


— 


tz 
\ 


NN poabady 


‘ er N 


ATX, BES) Berhudede 
Wie Wd le) 


OF EASTERN 


ORTH AMERICK: 


South Limit of the Ice-Sheet. 


Z Course of Motion » » >» » 


Driftless Area af Wisconsin. 


=e 


THe HEWIOTYPE PRINTINGCO. 220 DEVONSHIRE Sr. Bost 


GLACIAL DRIFT. 323 


in the earlier formed basin, but did not fill it up. There was rather more 
subsidence, showing that the tendency in modern times has been to 
enlarge rather than restrict the size of the bay. 

(6) The coldest part of the continent lies to the west and north of 
Hudson’s bay. A comparison of meteorological tables given in various 
arctic expeditions indicates a greater average degree of cold in the west— 
say at Fort Reliance in Rupert’s Land—than very far north. No greater 
degree of cold has been observed, but a lower average is reported for 
Greenland. For example: the lowest temperature indicated during the 
whole of one winter on the Hausa, which drifted along the entire east 
coast, was only —11° F. On the contrary, the average temperature for 
the four winter months,—December, January, February, and March,— 
for 1833-34, at Fort Reliance, as reported by Capt. Back, was —13°.9. 
For the winter ensuing, the average temperature for the same months 
was —21°.8. The Mackenzie valley, and the regions to the north-east, 
are noticed in meteorological treatises as remarkable for their cold. Be- 
ing so very cold, the continental parts west and south-west from Green- 
land would be favorable for the preservation of ice in the summer, and 
thus for its accumulation in enormous sheets as time progressed. 


Map or Nortu AMERICA. 


I have prepared a small map of the northern part of the continent to 
illustrate the dispersal of the drift. Observations will be found recorded 
there, indicating the directions of the movements in all the states and 
provinces so far as known. Reference to it will save much time in 
description. There is also represented the southern limit of the ice- 
sheet, the driftless area of the north-west, and the boundaries of the 
territory occupied by the Champlain deposits, termed the “Orange 
sand,” by Prof. Hilgard. All the geological reports of the several states, 
provinces, and territories, besides other volumes too numerous to be 
cited here, have been consulted for the preparation of this map, and it is 
believed to represent accurately the existing information respecting the 
dispersal of the drift. Where several courses have been described in a 
limited territory, only the predominant one can be given because of the 
smallness of the scale. Nor is the Rocky Mountain area delineated, 
since that belongs to a different centre of dispersion. 


324 SURFACE GEOLOGY. 


The facts seem to bear out the theory presented above of radial dis- 
persion from the Labrador peninsula in all directions except west and 
north-west. Observations are wanting for that part of British America. 
There seem to have been three centres of dispersion for our continent 
when the ice possessed its maximum development: Greenland, Labra- 
dor, and the Rocky Mountains. There seems, also, to have been a move- 
ment of icebergs up the St. Lawrence valley, possibly coeval with the 
Orange sand deposit. 


CAUSE OF THE GLacIAL Comp. 


Various theories have been proposed to account for the reason of the 
very severe climate of the glacial period. First, was the view that 
earthquake-paroxysmal waves passed southerly over both continents. 
Second, came the iceberg theory, involving a submergence of over 6000 
feet to explain all the phenomena. Third, the extreme glacial theory 
received much favor, where an elevation of the land was relied upon to 
produce the cold. If the land were extensively elevated, extreme cold 
would result, both because of increased cold in mountainous regions, and 
the deflection southerly of the warm oceanic currents. Both the iceberg 
and extreme glacial theories involve more extensive earth-movements 
than have appeared before in geological history, and hence do not fully 
commend themselves to general acceptance. There is no objection to 
the adoption of a modified glacial theory, such as has been advocated by 
A. S. Packard, Jr., where only 600 feet of elevation is called for to ex- 
plain the phenomena.* Prof. Dana, in the last edition of his Manual, 
seems to accept a modification of the enormous elevation—sooo feet— 
advocated in the first edition, though he does not say how great an up- 
rising of the land is called for. 

The less extreme our theories, and the less the variation from existing 
conditions required by our suppositions, the nearer will be their approxi- 
mation to truth. The following conditions probably existed, and by 
their combination brought about the extreme cold. 1. Elevation of land 
in the northern part of the continent for a few hundred feet, accom- 
panied by the necessary partial withdrawal of the warm oceanic currents 
in both the Atlantic and Pacific oceans. 2. Coincidence of longer 


* Memoirs Boston Society of Natural History, vol. i, p. 260. 


GLACIAL DRIFT. 325 


winters than summers, induced by precession of the equinoxes, with a 
period of great eccentricity of the earth’s orbit. This might have been 
cited as a fourth theory of glacial cold, and has been abundantly pre- 
sented earlier in the volume, page 5, ef seg. The coincidence of these 
astronomical and physical conditions would be fully adequate to produce 
the intense cold. 3. Some authors add the existence of conditions 
favorable to the abundant precipitation of moisture in northern regions. 
Certain collateral conditions seem to have been connected with these, as, 
4. The greatest accumulation of frozen moisture seems to have been 
‘about Labrador and Hudson’s bay, whence it pushed outwardly in all 
directions, but mainly southerly, because that was the direction of least 
resistance. 5. The accumulation of several miles thickness of ice seem 
necessary in order to understand how motion could be induced. The 
land about Labrador is not so high as the mountains of New Hampshire, 
and we cannot reasonably assume such an enormous elevation of it as 
would be required to cause the flow over New England, or to the plains 
of Dakota. 6. The adoption of Croll’s Molecular theory of ice-motion, 
or something similar to it, seems necessary. 7. The New England 
south-east movement probably resulted from the overflow of the St. 
Lawrence basin. The ice must have accumulated sufficiently to over- 
flow the St. Lawrence-Connecticut water-shed before it could have 
moved over the White Mountains. 8. How extensive the earlier south- 
west movement over much of New England may have been is not yet 
determined. Only scanty traces of it remain. 


INTER-GLACIAL Deposits. 


Messrs. Geikie and Croll insist upon the existence of warm periods in 
the midst of the long glacial winter sufficient entirely to melt the ice, 
and give rise to a succession of cold eons, alternating with the warm 
ones. Mr. Upham has already referred to the untenability of this posi- 
tion, page 7, and has described phenomena similar to those called inter- 
glacial by the Scotch authors (pp. 108, 131-137, 163, 164, 176, 290). It 
seems very clear that there are no phenomena in New Hampshire re- 
quiring us to accept the view of a succession of ice-periods. When the 
ice had once formed, it must have continued to rest upon the land 

VOL. III. 42 


326 SURFACE GEOLOGY, 


until the removal of the eccentricity of the orbit restored the warmer 
conditions. 

Two suggestions respecting the probable origin of all the inter-glacial 
deposits found in New Hampshire will not be out of place. 1. An ex- 
planation of Prof. Torell, of Sweden, is adequate to account for the 
example underneath the lenticular hill in New Ipswich,* and any other 
stratified beds in similar position. He represents that as the glacier 
commenced to exist and to move extensively, there must accumulate in 
favorable localities many stratified glacial deposits, so that a geological 
section of the edge of the ice would present (a) pre-glacial beds; (d) 
stratified glacial deposits; (c) a ground moraine; (d) the ice with its 
terminal moraine. Hence the advancing glacier may often cover strati- 
fied sandy deposits not of inter-glacial origin, 2. Our sections indicate 
that the stratified beds commonly occur between the lower and upper 
tills, as in Figs. 29, 32, 34, and 36. The Champlain fossils occupy the 
same position in the Portland section (Fig. 59). Assuming the correct- 
ness of our views regarding the origin of the two tills, all the inter- 
glacial phenomena are beautifully explained. It is not to be presumed 
that no variations in the position of the edge of the ice-sheet existed. 
The outer limit must have varied very much from time to time, just as 
it does at the present day in existing glaciers. When the ice retreated 
a few thousand feet, its melting would give rise to currents transport- 
ing sand. A change in temperature, or other conditions causing a re- 
advance of the ice-sheet, would cause the stratified beds to be covered 
again, and the mass might even push a short distance over marine 
deposits at the ocean border. But no ground moraine made its appear- 
ance with this reddvance. No deposits were left behind except the 
débris contained in the ice itself, or upon its surface; and this fell to 
the ground during the melting process, and now remains as the upper 
till. This distinction between the tills has been lately recognized by 
English and Scotch authors. It also appears that the British inter-gla- 
cial beds occupy the same position with ours between the two kinds of 
till,t so that probably our explanation of the New Hampshire beds would 


* This is situated just south-west of Jeft’s hill. By the side of the road an excavation shows about five feet of 
sand beneath the glacial drift, probably the lower till. The total thickness of the sand is not seen. In the over- 
lying drift I observed a boulder of porphyritic gneiss four feet in length. Between this point and New Ipswich 
village the road cuts through a sand containing boulders, which is also probably underneath the glaciated till. 


Tt ‘ The till or bouldereclay that rests above these intercalated beds usually differs from the stony clay which 


GLACIAL DRIFT. 327 


fit the corresponding cases in Europe. In such case the name “inter- 
glacial” would still be applicable to them, although not in precisely the 
same sense in which the term is now understood. The preposition 
inter would signify a place between the two tills. These do not prop- 
erly represent two glacial periods: they are different accumulations pro- 
duced by a single ice-sheet, with a varying outer edge. 


LENGTH OF THE GLACIAL PERIOD. 


I desire to call attention to another feature of glacial history that has 
been overlooked. Granting that the cold period commenced 240,000 
years ago, as determined by the orbital changes, it does not follow that 
it terminated 80,000 years since, when the extreme eccentricity disap- 
peared. The conditions would have been analogous to the state of 
things observed every year in our climate. The extremest cold of win- 
‘ter does not occur at the shortest day, but fully six weeks later, while 
the snow may continue till the first of May, though usually disappearing 
by the middle of April, so the great glacial winter would not have termi- 
nated with the end of the cycle. The prodigious quantities of ice and 
snow covering the northern latitudes would not have allowed the return 
of spring for many thousand years. If we were authorized to compare 
directly the annual duration of winter after the shortest day with this 
glacial period, it would be possible to fix the date of the disappearance of 
the ice. About one fourth part of our year elapses between the winter 
solstice and the vernal equinox. A fourth part of the long glacial winter 
would be 40,000 years. This would bring the close of the glacial, or, 
better, the Champlain period, to an epoch 40,000 years ago. If there is 
any variation from this estimate, it appears as if the subsequent period 
would have been shorter rather than longer, because of the enormous 
quantity of ice to be melted. 

The description of the events occurring in the Champlain period, such 
as the deposition of the kames and terraces, shows that the time of melt- 
ing need not have been greatly prolonged. The kames, being laid down 


immediately underlies them in being less hard and tough. It is often sandier and more frequently contains very 
large blocks and boulders, while at the same time its included stones and boulders are not so universally well 
smoothed and striated—or, to express it otherwise, angular unpolished stones and boulders are more common in 
the upper than in the lower mass of till. Again, I may note that the intercalated beds often thin out so as to 


allew the upper and lower deposits of boulder-clay to come together.””—Geikie’s Great Ice Age, second edition, 
revised, p. 19. 


328 SURFACE GEOLOGY. 


in ice-walled ravines, could not have taken many years for their accumu- 
lation; and if the higher terraces are remnants of the immediately suc- 
ceeding freshets, there is no reason to believe them long continued. Fol- 
lowing out the analogy of seasons as already commenced, this should be 
compared with the spring freshets. These require very little time for 
their rise, culmination, and termination, while they may occur at succes- 
sively later and later points of time, as you pass from the mouth to the 
source of the streams flowing southerly. 

The time when man was introduced is connected with the figures as- 
signed for the termination of the glacial period. There seems no like- 
lihood that our ancestors would have found the conditions of life favorable 
to their existence among the glaciers, so that they would not have emi- 
grated here from warmer latitudes before the Champlain period. No 
certain evidence of man earlier than the Champlain period has yet been 
discovered in any part of the world. Hence there is little reason to be- 
lieve he was introduced more than 40,000 years ago.* 

Recent Scotch authors insist upon a greater antiquity for man than 
this, because his implements have been found in the inter-glacial beds, 
thus carrying him back at least 100,000 years. The observations stated 
above intimate the unreliability of the theory respecting the great antiq- 
uity of these inter-glacial beds. Those in New Hampshire can all be 
accounted for without assuming the intercalation of warm periods into 
the glacial age. It would be ungracious to assume that our phenomena 
should be taken as the standard of measure for those elsewhere; but as 
very few other writers have perceived the distinction between the lower 
and upper till, we desire to be informed whether their inter-glacial beds 
cannot be referred to a place between the two kinds of drift, before ac- 
cepting the Scotch conclusions. The use of astronomical calculations 
in the determination of the duration and definite place of the glacial 
period is of great importance, and if thoroughly proven will form a basis 
for the establishment of a geological chronology, not merely for the latter 
part of the Cenozoic, but of all time, even to the era of the Eozoén or 
the simpler denizens of the Eophytic period. 

Mr. Upham has prepared some brief statements respecting the relative 


* This is given as the remotest possible date for the introduction of man. Other evidence might be pre- 
sented illustrating the fact that very exaggerated notions of the great age of man prevail at the present day; 
but the subject has no connection with phenomena discovered in New Hampshire, and is therefore omitted. 


GLACIAL DRIFT. 329 


heights of land and sea during the glacial and Champlain periods. They 
are the result of much reflection upon his part, and are worthy of careful 
consideration. 


CHANGES IN THE RELATIVE HeIcHTs or LAND AND SEA DURING THE 
GLACIAL AND CHAMPLAIN PERIODS. 


By Warren UrHam. 


Evidence has been found of the accumulation of immense ice-sheets, 
probably in the same epoch, over the north part of America, Europe, and 
Asia, also in New Zealand and the south part of South America. This 
‘points to some cosmical cause for the glacial period, like that assigned by 
Croll, rather than to the causes appealed to by Lyell and Dana, namely, 
elevations of the earth’s crust. It would be a very improbable coinci- 
dence that such extensive regions surrounding both poles should be thus 
elevated in the same period; but these would obviously be the parts of 
the globe to be covered by ice if its origin was due to eccentricity of the 
earth’s orbit. There seem to be reasons (pp. 7-9), however, to discredit 
the conclusion of Croll, that the ice-sheets were alternately wholly melted 
away in each hemisphere once in every 21,000 years; instead of which 
it seems probable that the ice-mantle existed upon both hemispheres at 
the same time. 

The effect of this extraordinary accumulation of ice about the poles 
would be to take away a large amount of water from the ocean, and, fur- 
thermore, to draw the sea, by gravitation, away from the equator, leaving 
the sea-level lower than now within the tropics, but at the same time 
causing it to rise even higher than now near the lower limit of the ice- 
sheets, and much higher than now near the poles. Marine shells in the 
modified drift show that the sea thus rose 150 to 200 feet above its pres- 
ent height in the latitude of New York city; 500 feet in the valley of the 
St. Lawrence; and 1,000 to 2,000 feet in arctic regions. Everywhere in 
high latitudes, both in the northern and southern hemispheres, we have 
proof of such a submergence of the land when the drift was accumulated, 
increasing in amount the nearer we go to the poles. On the other hand, 
the coral islands of the tropics are witnesses of a depression of the sea, 
amounting to 3,000 feet or perhaps much more at the equator, while dif- 
ferent proof shows that at the mouths of the Mississippi, Ganges, and 


330 SURFACE GEOLOGY. 


Po rivers it was at least 400 feet. If we reflect upon the widespread 
changes of sea-level that marked the glacial period, occurring only where 
they would be produced by taking water from the sea to form the ice- 
sheets, and by gravitation through their influence, and if we compare 
these recent simultaneous changes with the general stability of the con- 
tinents, it seems reasonable to attribute them to movements of the sea 
rather than of the land. 

In North America the southern edge of the ice-sheet varied from 38° 
to perhaps 50° north latitude. Nearly all of the continent north of this 
line, with portions of the sea next to the coast, the archipelago farther 
north, and much of the Arctic ocean, Hudson’s and Baffin’s bays, and 
Greenland, were probably covered by ice in the glacial period. This 
would be about one twenty-fourth part of the whole area of the globe. 
In the eastern hemisphere, Europe and Asia were apparently overspread 
by ice as far south, on the average, as to 50° north latitude. The North 
and Baltic seas, and a considerable part of the Arctic ocean, are to be 
added, making an area, as before, equal to about one twenty-fourth part 
of the earth. The glacial sheets of the antarctic continent and adjacent 
ocean, with Patagonia and its sea-border, were probably equal to each of 
the foregoing, so that in all about one eighth of the earth’s surface was 
covered by ice. If a slope of one half of a degree is needed to cause 
the motion of these sheets of ice, an estimate of four miles for their aver- 
age depth does not seem to be too great. The removal of the water thus 
taken from the sea and stored up in accumulations of ice would lower 
the surface of the ocean more than a half mile. 

The effect of the ice-caps to draw the sea towards the poles remains 
to be considered. Because the ice was limited to high latitudes, its influ- 
ence to raise the ocean over these areas would be much greater than if 
the same amount of ice had been spread in a thin covering, reaching, with 
gradually decreasing depth, to the equator. It may therefore be near the 
truth, to consider the effect in gravitation over glaciated regions to be 
the same as would result from an increase of the polar diameter by twelve 
miles of ice. This would be massed, as we have seen, in the proportion 
of two to one about the north and south poles, the greater part being 
accumulated in the northern hemisphere; still, the effect upon the sea- 
level would be nearly alike about both poles, in the same way that the 


GLACIAL DRIFT. 331 


moon produces two tides, one on the side next to it, and the other ex- 
actly opposite on the earth’s surface. Now the specific gravity of ice, 
compared with that of the earth as a whole, is about as one to six, 
Therefore the ocean would be raised one mile at each pole, or nearly 
a half mile above its present height. At the same time, because all 
the ice was massed in high latitudes, it seems probable that everywhere 
within the tropics the sea would fall, through the influence of gravita- 
tion, below the depression of a half mile, which resulted from the removal 
of water to form ice. 

These glacial sheets, when at their greatest extent and depth, caused: 
the sea to rise 200 feet higher than now at Long Island, as shown by ma- 
rine shells. At a somewhat later date, when the ice-front was retreating, 
the sea stood on the coast of New Hampshire and Maine 150 to 225 feet 
above its present level. Probably at this time so much of the ice north- 
ward had disappeared that this height does not correspond to that of 
200 feet at Long Island; for we have evidence (in the sub-marine chan- 
nel of Hudson river) that after the ice began to retreat, the sea-level at 
New York was depressed till it was at one time 600 feet or more below 
its present height. When the sea was elevated 200 feet upon the coast 
of Maine, or perhaps later, it stood 500 feet higher than now in the vicin- 
ity of Montreal and along the St. Lawrence valley. This somewhat 
greater height than we might expect seems to have resulted from prox- 
imity to vast depths of ice resting upon the highlands of Canada and 
Labrador. Near the middle of the Champlain period, when the ice-sheet 
over the northern United States and the south part of British America 
had principally melted away, but while immense ice-fields still lay farther 
to the north, the amount of water restored to the ocean would not proba- 
bly raise it more than half of the whole amount that it had been de- 
pressed. At this time the tendency from gravitation to raise the sea- 
level at the latitude of New York would be small, and no longer suffi- 
cient, as when the ice-sheet had its greatest extent, to counterbalance 
the depression, so that the sea might stand 600 feet or more lower than 
now at New York, while the Hudson must form a channel now covered 
by the sea. 

The testimony on this subject, which we have from Long Island and 
the submarine channel of Hudson river, may be summed up as follows: 


332 SURFACE GEOLOGY. 


When the ice-sheet over New York and southern New England melted, 
the sea stood, at least for part of this time, about 200 feet higher than 
now.* At this time the extensive plains of modified drift, forming the 
south side of Long Island and the submarine plateau that extends fully 
fifty miles south and south-west to the New Jersey shore, were deposited, 
being spread nearly level by the waves and currents of the sinking ocean. 
The valley of the Hudson river was also filled with modified drift to a 
height at Albany of 330 feet above the sea. The submarine channel 
proves that after this the sea-level was depressed at least 600 feet lower 
than now, while immense floods pouring down the Hudson valley exca- 
vated these deposits below our present sea-level from Albany southward. 
This channel at Haverstraw bay and the Tappan Zee is two to five miles 
wide. Its south-east portion with the areas on each side is now covered 
by the sea, but it is plainly traceable by soundings for more than a hun- 
dred miles south-east from New York bay. This channel must have 
been excavated, as we have shown, after the melting of the ice-sheet 
over southern New England and New York, for otherwise it would have 
been filled with the modified drift which forms submarine plains on each 
side. 

Although the deposition of modified drift seems to have ended in this 
region before the sea was thus depressed and this channel of the Hud- 
son was formed, it still appears that very immense floods were discharged 
here. The ice had probably retreated from the most of New York state, 
and mainly from the basin of the great lakes, but still obstructed the St. 
Lawrence valley, turning a large part of the floods of this basin into the 
Mohawk and Hudson. This submarine channel thus appears to belong 
to the same epoch in which the beach-ridges about the great lakes were 
being formed. 

At the east edge of the sketch map? representing this former ex- 
tension of Hudson river, may be seen (south-south-east from Montauk 
point) the similar channel of Connecticut river in the same period, less 
notable than that of the Hudson, because the latter discharged vastly 
greater floods. A difficult point in our surface geology, which was be- 
fore unexplained, is made clear by this depression of the ocean below its 


* A bed of marine shells at this height in the modified drift of Long Island is described by Mr. Elias Lewis, Jr., 
in Popular Science Monthly, vol. x, p. 440. 
+ Dana’s Manual of Geology, p. 441; new edition, p. 422; and Popular Science Monthly, vol. x, p. 444. 


GLACIAL DRIFT, 333 


present level, following the departure of our part of the ice-sheet. In 
the first chapter of this volume it was shown that very large amounts of 
modified drift were excavated by the rivers in deepening their channels. 
Taking Connecticut and Merrimack rivers as examples, it seemed inex- 
plicable, if the ocean from being 150 feet higher than now simply fell to 
its present level, to account for the disappearance of all the modified 
drift eroded between the upper terraces of these valleys. This explana- 
tion of the Hudson submarine channel is made more worthy of our 
belief because it also solves this difficulty. If the ocean was thus de- 
pressed, the modified drift excavated would be carried by the descending 
streams beyond our coast-line. W. U. 


ORIGIN OF THE BLUE AND Gray CLays. 


In the first chapter (pp. 94, 153-155, and 158-161), Mr. Upham has 
brought together various facts respecting the distribution of the blue 
and gray clays overlying the till) He finds that the former invariably 
underlies the latter. This is true throughout New England, but not in 
the Western States, where alternations of the two kinds have been ob- 
served. The reason of this invariable order in the east has never been 
given satisfactorily. In order to contribute to the solution of this prob- 
lem, I requested Mr. Upham to select for analysis typical specimens of 
the two tills and clays. Mr. G. W. Hawes presents the following as the 
result of their chemical examination. Only the iron percentages were 


determined: 
Upper till. Lower till. Gray clay. Blue clay. 
Iron protoxide, 3 ‘ ‘ 1.42 1.75 2.75 3-17 
Iron sesquioxide, . , ‘ 1.56 0.006 4.15 2.53 


The tills came from Alton, the clays from Dover. The facts indicated 
are,—the proportionate increase of the sesquioxide of iron in the upper 
over the lower till, and in the gray over the blue clay; also, the clays 
contain more iron than the till. These facts are sufficient to explain the 
difference in color. They agree with the theory already propounded for 
the origin of the two tills,—that the first resulted as a ground-moraine 
from the pulverization of the rocks, and the second from the dropping 
VOL. I. 43 


334 SURFACE GEOLOGY. 


down of all the materials in the ice-sheet at the time of melting. The 
upper deposit would be loosely aggregated and more highly oxidized 
than the lower beds, because the opportunities for the addition of oxygen 
were more favorable. 

The very first question suggested by the position of the analyses is, 
whether the gray clay has not been derived from the upper and the blue 
from the lower till. The two classes of deposits agree in their chemical 
character, color, and superposition. I will advocate the affirmative an- 
swer to this question, and state how the conditions would favor such a 
derivation. 

The blue clay is not continuous throughout the Connecticut and Mer- 
rimack valleys, but occurs in definite and limited areas, as has been set 
forth in Chapter I. Its origin may be conceived to be like that of similar 
clays near the mouths of glaciers. The water gathering from the various 
sub-glacial rills gathers the fine clayey material pulverized by the motion 
of the ice, and transports it to some lake or place of comparative quiet, 
and the sediment is deposited as a blue clay. In Hooksett and Pem- 
broke is a mass of clay four miles or more long. Suppose that the gla- 
cier were still unmelted above Franklin, the pulverization of the rocks 
on the upper Pemigewasset would furnish an abundant supply of clay, 
which might have been transported to Hooksett before the current 
slacked sufficiently to allow the turbid water to settle. In this way the 
blue clay might have been formed, and it would have been derived alto- 
gether from the lower till, Subsequently, we may suppose, the ice be- 
gan to melt more rapidly, and the detrital residue, or upper till, would 
be subjected to carriage. The first result would be the soiling of the 
streams with the more oxidized clay, and there would be formed the gray 
deposit over the blue. In the continuation of the process, the streams 
would become still larger, and the material brought down would be sand 
covering the gray clay; or the gray clay may be conceived to be the re- 
sult of the washing of the upper terrace deposits. The finest particles 
in the case of a washing would be the first to show themselves low down 
the valley; and the material exposed is essentially the upper till. 

This view explains how the formation of clay may be connected di- 
rectly with the ice. The ice nearest the edge of the sheet, or on the 
ocean border, first melted, producing the upper till and a massive clay. 


GLACIAL DRIFT. 335 


The next stage of the process would naturally be the deposition of blue 
clay, derived from the ice twenty or fifty miles away, and resting upon 
either of the tills where the glacier had once been present. When all 
the clays and sands had been supplied to the second area, the scene of 
action was transferred to a locality still nearer the ice, and so on till the 
whole had disappeared. Throughout the valley the clays overlie the 
till, although the stratified beds low down may have existed while the 
lower ground-moraine was forming among the mountains. The order of 
the conditions and of the deposits was strictly uniform, although at the 
present time it is difficult to realize that a clay at Newburyport should 
have been formed earlier than the same material at Hooksett. Some 
have imagined that no clay was formed till after the entire disappearance 
of the ice. In that case, we could not have had two kinds of clay. The 
waters washing away cliffs would mix together the protoxide and sesqui- 
oxide débris, and the resultant deposit would be unlike either of the beds 
now situated beneath the many brick-yards. 

This view is in agreement with previously expressed suggestions about 
the rapidity of the accumulations of modified drift. The principal work 
of depositing the modified drift belongs to the epoch of the melting of 
the ice; and, following the analogy of spring freshets, the time must 
have been comparatively short, whether as compared with the antecedent 
glacial or the subsequent alluvial period. 

Mr. Hawes expressed different views about the origin of these clays 
when the analyses were returned. I subjoin extracts from his letters: 


My interpretation of those analyses was something as follows: Finding only cron 
protoxide in the lower till, I thought the analyses indicated that, at the time of its de- 
position, the whole till contained iron only in the lower state of oxidation; that, being 
formed beneath the glacier by the grinding and pulverization of the rocks, it had no 
opportunities to oxidize. The upper till is lighter in color on account of the oxidation 
of its iron by the subsequent action of the atmosphere and percolating waters, which 
action has proceeded only to a certain depth. In being washed down into the valleys, 
a portion of the iron was oxidized,—and hence the Jower clays contain iron oxide; and 
after the clays were deposited, the external agencies of air and water, acting on them 
as on the till, oxidized more iron in the superficial portion, making them again lighter 
in color than the lower clays. Thus the two colors of the till and of the clay are both 
referable to one cause,—the action of external agencies that have been in operation 
since the time of the deposition of these deposits, and are still in progress, driving the 


336 SURFACE GEOLOGY. 


dividing line deeper down. The fact of the presence of more iron in the clay than in 
the till is readily supposable, since iron is quite likely to be concentrated with the finest 
materials in the lowlands, leaving coarse pebbles behind. This, I think, answers all 
your questions, as I had understood the matter; but you will be the best judge as to 


the correctness of the suppositions. 
The second letter is as follows: 


In reference to the questions you propose in your last letter, you understand that I 
ain unfamiliar with the field facts and the geological relationships involved, and so am 
not very able in my opinion. As I understand you, your opinion is, that the lower till 
was made from the clay derived from the grinding of the rocks by the lower surface of 
the glacier, and the upper till from the rubbish in and on the glacier, which was depos- 
ited on the melting of the glacier; and that subsequently the lower blue clay was de- 
rived from the lower till, and the upper gray clay from the upper till, by transportation 
by water; and you put the questions, ‘‘ Could the lower blue clay have been derived 
from the lower till by deposition in water?” and ‘Could such material be transported 
without oxidizing the iron?” It does not seem to me that the lower clays could be 
derived from lower till, for if the washing took place after the deposition of the till, the 
strata of the till would be inverted in the clay beds, and the upper till would make the 
lower clay, since it would be the first to be transported by erosion. I do not think that 
material could be transported without any oxidation of ferrous compounds; but as the 
lower blue clay contains ferric oxide, this is not necessarily supposed. I incline to my 
former opinion of the production of an upper gray layer, in both cases, by those pro- 
cesses of oxidation,—by the external agencies that are everywhere going on in the 
rocks as well as soils. If, now, as is believed, the end of the glacial period was accom- 
panied by great floods, and the latter end of the melting was rapid, the material in and 
through the glacier would not be deposited on the ground on top of the lower till, but 
would be washed away, and concentrated in the gravel beds. Clays in some cases may 
have resulted from the deposition of the finer portions, assorted by the rapidity of cur- 
rents; but the material is usually coarse that rests on and in glaciers, and composed of 
broken fragments. The fine clay is that which is ground and pulverized by the lower 
surface grinding the underlying rocks. If, then, the till on the disappearance of the 
glacier was a substance uniform in composition from top to bottom, and of the same 
nature as the present Jower till, then, by the action of running water, material from 
this bed might be transported to form clay beds without further oxidation of the iron 
than is shown by the difference between the lower till and lower blue clay. If the beds 
of both till and clay, as first deposited, were of the same nature.as the lower beds at 
present, atmospheric and aqueous agencies would in time produce the differences in 


both now seen. 


In speculating upon this subject, I was at first troubled by the some- 
what similar origin of the upper till and blue clay, both in connection 


GLACIAL DRIFT. 337 


with water. Why should the former be so much and the latter so little 
oxidized? Relief came by examining the analyses. The blue clay con- 
tains more sesquioxide than the lower till, just as would be expected from 
the nature of the deposit. Furthermore, all blue protoxide clays have 
- come from deposition in water ;—hence there is nothing abnormal in be- 
lieving in the origin of the lower clay from the older till. 


OrvER oF EVENTS. 


The following list of occurrences expresses our most récent opinions 
respecting the order of events occurring in New Hampshire in the Gla- 
cial, Champlain, and subsequent periods : 

1. The country was covered presumably with forests of late Tertiary 
type, partly exhibited to us by the nearest fossils, yet of Eocene age, in 
Brandon, Vt. The beech, bass-wood, buckeye, Aristolochia, peperage, 
and cinnamon have been found there, with some others allied to the 
conifere. The change of climate induced by the change of land, com- 
bined with astronomical causes, would destroy most of these plants, and 
render the region sterile. Then the ice commenced to spread over New 
England, with alternate meltings of limited extent, so as to give rise to 
beds of sand and gravel. 

2. The ice accumulated in the St. Lawrence valley so as to flow over 
New England, possibly preceded by a south-west current. The whole 
country would have been covered by a sheet of ice, thousands of feet in 
thickness,—probably 7,000 or 8,000 feet in the lower part of the state, 
flowing south-east towards the ocean. This was the period of the forma- 
tion of the lower till, and of the great terminal moraines of lower New 
England. The broad sandy plains of Cape Cod and Long Island mark 
the beginning of the Champlain period. 

3. The melting of the ice has progressed steadily until no more ice is 
supplied from the St. Lawrence valley. New Hampshire is now covered 
by local glaciers, pushing down the Connecticut, the Merrimack, and 
other streams. The lower fossiliferous deposits of the coast are coeval 
with these glaciers. Variable seasons cause temporary advances and 
retreats of the ice, and thus allow of conditions favorable to the produc- 
tion of the inter-glacial beds. 

4. The thermal influences prevailing, the ice is driven back to the 


338 SURFACE GEOLOGY. 


mountains ; the débris which it contained forms the upper till; the 
kames show themselves, deposited between walls of ice ; and the valleys 
are filled with plains of modified drift, including the blue and gray clays. 

5. The terraces are produced by excavations of the last formed de- 
posits; vegetation and animal life return; the horse and wild boar, whose 
remains have been found with us, flourished. 

6. A warmer period followed, as illustrated by the presence of the 
rhododendron, cedar, and other plants upon the land; the quahog and 
oyster in the ocean, and the introduction of the American aborigines. 

7. A somewhat colder climate, only a few hundted years back from 
the present date, ensued; New Hampshire was colonized by Europeans; 
and the present type of civilization has abolished the forest and exter- 
minated the larger forms of animal life. 


NoTEs ON THE SuRFACE GEOLOGY oF Coés County. 
By J. H. Hunrincron. 


Fluvial Deposits. These frequently have the appearances, as far as outline is 
concerned, of ordinary river terraces; but an examination of the material of which 
they are composed shows that they have an entirely different origin. In these the ma- 
terial is very coarse ; and we often find boulders 8 or ro inches in diameter. Usually 
they are not very extensive, and they are found only at the mouths of very rapid 
streams. The most extensive deposit of this is in Pittsburg, near the mouth of the 
stream which is the outlet of Back lake. Was all this coarse material, which occupies 
an area of many acres, brought down by the present stream? Mr. David Blanchard, 
who is well acquainted with the outline of the country, thinks that Perry stream once 
had its outlet here. The theory is very plausible, and there is little doubt but that such 
was the case. The barrier of rocks where the road crosses this stream, when it was a 

' few feet higher than it is now, would have turned Perry stream into Back lake; thence 
it would have followed the course of the present outlet of that lake. Most of the drift 
that has been brought down by Indian and Hall’s streams is of the same coarse mate- 
rial. Another deposit of this character is in the town of Stark along Nash stream. 
Almost every stream that comes down from high lands or mountains has brought down 
immense quantities of this kind of material, but nowhere to the extent that has been 
done in the localities just mentioned. How was this deposit formed? The present 
amount of water could not, even at times of the highest floods, have brought down this 
material and deposited it as we now find it. The resource to which we are led to explain 
this phenomena is this: At the time of the final retreat of the glaciers, just before they 
disappeared entirely, they were confined to the deep ravines of the high lands and the 
mountains. The melting of the glacier and the snow, with copious rains, for the moist- 


GLACIAL DRIFT. 339 


ure-laden currents coming in contact with these fields of ice would have been suddenly 
condensed,—all these would have had a tendency to produce floods that are now un- 
known. 

Kames. The best examples of kames seen in Cots county are those which were 
formed as the glacier retreated from the valley of the Connecticut, in Columbia and 
Colebrook, and nowhere are they more striking than at Colebrook village. These are 
interesting, from the fact they show that for years the great glacier that filled the valley 
of the Connecticut here had its terminus. The fact that these gravel ridges do not ap- 
pear above Colebrook shows that the change of climate was such as to cause the glacier 
to disappear rapidly when it receded above that point. The expansion of the valley 
at the village and just above, and its contracted limits below, were also causes that may 
have produced this phenomenon. 

Erratics, There are very few but that have noticed, scattered through the fields, 
boulders unlike those of the rocks in the immediate vicinity. These boulders we call 
erratics or wanderers, because they have come from some distant place. Throughout 
northern New Hampshire, on account of the extensive tracts of forests, the study of all 
phenomena of drift is pursued under the most unfavorable circumstances, since in the 
forests there are no excavations, except that done by water along the streams. The 
boulders as well as the ledges are much more commonly covered with earth, or, at 
least, they are overgrown with moss, which has to be removed before we can tell 
anything about the rocks. To study thoroughly the geography of a country covered 
with forests, would, under most circumstances, be an endless task, although the area 
might be quite limited. On account of the fragile nature of many of the rocks in the 
extreme northern part of the state, boulders are not so numerous as in some other 
sections ; and the absence of granite boulders is especially noticeable. North of Con- 
necticut lake I do not remember to have seen but one granite boulder in all that 
area, and that was three or four miles east of Third lake. On Indian stream, eight or 
ten miles from its mouth, there were several boulders of conglomerate, and just north, 
three of brecciated iron ore. In Colebrook, near Mr. L. Dinsmore’s, there is a con- 
glomerate which is quite attractive even in hand specimens. None of these just men- 
tioned were found in place, and where they came from is a matter of conjecture; but 
it is altogether probable that they came from Quebec province. Most of the boulders 
found in New Hampshire as far south as Columbia are derived from the hard bands in 
the argillaceous schist, or they come from the band of hornblende rock extending from 
Colebrook to the boundary. Everywhere south-east of this band, as far as Maine and 
even beyond the Magalloway, boulders of this rock are seen. As the rock is unlike 
any other, they are noticeable wherever they may be found; and they show that the 
general direction of the drift was considerably east of south. 

In Stratford, just north of Little Bog brook, there is quite a remarkable collection of 
granitic boulders, both on account of the number and the limited area where they are 
found ; besides, they must have come from Vermont, as granitic rocks of this kind are 
not found in New Hampshire. 


340 SURFACE GEOLOGY. 


In Errol, along the road to Upton, Me., we find an abundance of boulders of gran- 
itoid gneiss, which probably came from the vicinity of Wentworth pond. In Milan, 
particularly in the vicinity of Mr. Moses Hodgdon’s, we find boulders of sienite that 
must have come from Mill mountain in Stark, or from the hill immediately north; con- 
sequently the drift here could not have been more than fifteen or twenty degrees south 
of east. There are two remarkable collections of boulders in the south part of Bean’s 
Purchase, though they are derived, evidently, from ledges near where they are found. 
One of these is found a mile south from the summit of the Carter notch. The boulders 
are piled up so that they form a barrier across the valley, which is perhaps fifty feet 
higher than the depression towards the notch, in which there are two small ponds that 
have no visible outlet; but the water finds its way by an underground passage through 
the barrier, and where it issues from the rocks it forms quite a large stream. Above 
the barrier there are also many large boulders that have fallen down from the sides of 
the notch. Everywhere the boulders are angular, and their detachment from the ledges 
must have been quite recent. 

Another remarkable collection of boulders is on the east branch of the Saco, a few 
miles east of the last mentioned. Here the rock is a gneissoid granite. The boulders 
are of immense size, and are scattered over an area of half a mile in width. They are 
everywhere covered with moss; and this supports a growth of firs, which are from eight 
to ten feetin height. Travelling is extremely difficult, both on account of the trees 
and the size of boulders. After a heavy rain, far down among the rocks streams of 
water flow, the existence of which would not be suspected if they could not be heard. 

Lake Margins. The effect of the expansion of ice on our lakes, although noticeable 
in many places, is nowhere so marked as on the margin of Connecticut lake. At low 
water the rocks can be seen piled up in a wall-like structure, which on the south shore 
has a height of three or four feet, in places almost vertical. These rocks have been 
pushed a little year by year until they reached their present position, and were beyond 
the reach of ice-pressure. As the lake is now several feet above its natural level, a 
dam having been built at the outlet, if kept thus this wall will in time be removed to a 
higher level. 


APPENDIX TO PARTS I AND II. 


APPENDIX A. 


DISTANT POINTS VISIBLE FROM MT. WASHINGTON.* 


By W. H. Prckerinc. 


F an observer were to go up four particular peaks in the White Mountains he 
could see all the distant points visible from any of the other summits, together 
with a good many more not visible from them. These four peaks are Washington, 
Moosilauke, Passaconnaway, and Lafayette. I name them in the order of the extent 
of the distant views obtained from them alone. Now, looking at the subject the other 
way, no matter from what distant point the White Mountains are seen, one of these 
four points must always be the most conspicuous object in view, provided no near hills 
intervene. By means of the following formule the distance visible from any mountain 
may be readily calculated, and also the elevation a mountain must have in order to see 
acertain distance: d=4,/ h, h—=4d?, where d=distance in miles, and 4= eleva- 
tion in feet. They may also be used to calculate mountain profiles as seen from dis- 
tant points. In this connection I may add that there is a slight inaccuracy in the 
Guide Book relating to Chocorua. It says,—‘‘It is the noblest peak in all the view 
from Washington, and lifts its white pyramidal ledges far into the sky, flanked by bare 
supporting ridges.” This must be a rhetorical hyperbole, for it is not at all true. 
And far from lifting its pyramidal ledges into the sky, it does not even come up to the 
level of the horizon by 420 feet. 

For some time there has been a question whether Katahdin was visible from Wash- 
ington or not. It is 163 miles distant, and would be the most distant point from which 
ithe White Mountains could be seen. According to calculation, 3500 feet of it should 
be visible if the land between were on the level of the sea. Now the horizon line as 
seen from Mt. Washington passes five or ten miles south-west of Moosehead lake. 
Moosehead lake has an elevation of 1023 feet above the sea. Now, allowing the land 


* Read before the Appalachian Mountain Club, October 11, 1876. 


344 APPENDIX TO PARTS I AND II. 


five or ten miles below it, measured on the river, to have an elevation of 1500 feet, 
Katahdin would still rise 1170 feet, and it would require an elevation of 2300 feet to 
hide it. Moreover, on remarkably clear wintry days, a very distant mountain has been 
seen in about the right direction, with a very peaked summit, which coincides with the 
descriptions of Katahdin. I should add, however, that as seen from Moosehead lake, 
which is in much the same direction, Katahdin does not present this appearance. It is 
claimed by some that Katahdin is visible from Kiarsarge ; and there is a distant moun- 
tain visible from there on rare occasions, which I have seen once, but which is not in 
the right place. And, moreover, if there was an elevation between them of 390 feet 
above the sea, and near Mt. Blue, Katahdin would be hidden. Now, as all the 
country near Mt. Blue has an elevation of something over 1000 feet, it seems rather 
improbable that Katahdin should ever be seen. As to seeing it from Osceola, as 
some claim, one would have to look something like 100 feet below the sea horizon to 
see it. 

The following is a list of some of the more interesting distant points to be seen from 
Mt. Washington, many of them being visible only on rare occasions: 

Mt. Belceil: distance 135 miles, position north 45° west, and nearly over Prospect 
hill, Lancaster. It is quite a high mountain near Montreal, and is said to be visible. 

Lake Memphremagog: distance 70 miles, position north 40° west, and over Jefferson 
hill. It requires a very clear day, as distant water is difficult to distinguish. 

Mt. Carmel: distance 65 miles, position north 10° east, and just over Mt. Adams. 
It is very near the northern boundary of Maine, and is readily recognized by the steep 
slope on the eastern side. It is said that a very fine view may be obtained from it. 

Mt. Bigelow: distance 70 miles, position north 35° east, and nearly over Mt. Hayes. 
It appears as three rounded hills. Just to the south of it, and far beyond, is a moun- 
tain with a very sharp apex, which is sometimes called Katahdin, but this is a mis- 
take. 

Mt. Abraham: distance 65 miles, position north 40° east, and somewhat to the right 
of Mt. Hayes. A long serrated ridge, also sometimes called Katahdin. 

Mt. Katahdin: distance 103 miles, position north 45° east, and about half way be- 
tween Mt. Hayes and Mt. Moriah. It is said to appear rising over a nearer saddle- 
shaped mountain, and to be recognized by its sharp peak, the sharpest in all the view 
from Washington. If visible at all in summer, it would be far the faintest object in 
sight in that direction. 

Mt. Blue: distance 57 miles, position north 57° east, and half way between Surprise 
and Moriah. It is quite a conspicuous pyramidal peak, and is near Farmington, Maine. 
It is used as a Coast Survey station. 

Portland: distance 65 miles, position south 51° east, and over the northern summit 
of Doublehead. It appears as a low white hill, with a long light-blue line beyond it. 
With a telescope the hill resolves itself into a mass of closely packed white houses, 
and the blue line is seen to be thickly studded with sails. The ocean, however, is not 
as often seen as some more distant objects in other directions, partly on account of the 


DISTANT POINTS VISIBLE FROM MT. WASHINGTON. 345 


difficulty of distinguishing distant water, and partly because the atmosphere in this 
direction seems generally to be somewhat thicker than elsewhere. 

Lake Sebago: distance 43 miles, position south 48° east, and over Mt. Gemini. It 
is 14 miles long, and about 11 wide. 

Mt. Agamenticus: distance 80 miles, position south 24° east. A flat rounded hill 
of considerable height in the southern part of Maine, and forms a conspicuous land- 
mark for sailors. 

Isles of Shoals: distance 97 miles, position south 22° east. They are very difficult 
to see, and are situated on the horizon just to the right of Agamenticus. 

Mt. Wachusett: distance 126.5 miles, position south 13° west, and just to the right 
of Whiteface, if it is visible. 

Mt. Monadnock: distance 104.5 miles, position south 22° west, and a little to the 
right of Sandwich Dome. A very regular rounded summit. 

Mt. Kearsarge: distance 70 miles, position south 24° west, and half way between 
Sandwich Dome and Carrigain. 

Mt. Uncanoonuc: distance 92 miles, position south 9° west, and half way between 
Mts. Crawford and Passaconnaway. Twin summits near Manchester. 

Mt. Ascutney: distance 85 miles, position south 45° west. Situated in Windsor, 
Vermont, close to the Connecticut river. 

Killington Peaks: distance 91 miles, position south 59° west, and between Mts. 
Liberty and Blue. Twin peaked summits near Rutland, Vermont. 

Camel’s Hump: distance 80 miles, position north 87° west, and just over Bethlehem 
street. It is a striking looking mountain, shaped like a truncated cone, with very steep 
sides. Readily visible at sunset on a clear day. 

Mt. Whiteface: distance 130 miles, position north 86° west. It is just barely visi- 
ble, hardly rising above the right hand slope of Camel’s Hump. This is one of the 
highest of the Adirondacks, rising to a height of 4900 feet. Two lower peaks are seen 
just to the right, and three more some distance to the left. These however have not 
yet been identified, but if Mt. Marcy and any of the other higher summits are visible, 
they should appear about 7° to the south of Whiteface, and nearly over the Fabyan 
house. 

Mt. Mansfield: distance 78 miles, position north 78° west, and between the Twin 
Mountain house and Mt. Deception. It is the highest of the Green Mountains, being 
4300 feet high, and appears as a long ridge bearing a fancied resemblance to a human 
face. 


346 APPENDIX TO PARTS I AND Il. 


APPENDIX B. 


ALTITUDES, Contour LinEs, AND RatsED Maps. 


During all our explorations of the state for the study of its geology and the collection 
of rock-specimens, frequent barometric measurements have been also obtained, and the 
prominent topographic features of the country have been carefully noted. Only a small 
portion of all the heights thus measured appear in Volume I (pp. 210, 211, and 242, 
chap. x, and pp. 304-314), the altitudes there given being those of mountains, villages, 
ponds, or other points of special interest. Since the publication of that volume, many 
additional barometric observations have been made. 

The information thus gathered respecting the configuration of the state, although 
incomplete because it has been impossible to make a detailed examination of our entire 
territory, yet seemed worth preservation, and sufficient to justify an attempt to present 
contour lines on the new map accompanying this report. Numerous series of altitudes, 
accurately determined by surveys for railroads, or by levelling done specially for the 
geological survey, have formed a basis to which the barometric measurements have 
been referred. According to these observed heights, and others estimated for adjacent 
hills and valleys, lines of contour for each one hundred feet above the sea were first 
drawn on the county maps of large scale, which had been used in our explorations, and 
thence were transferred to the draft of the new map. ‘These lines have been engraved 
separately from the rest of the map, so that they may be printed in a color different from 
that of the streams, roads, boundary-lines, names, etc. They are thus easily distin- 
guished from all other lines, but are required to be printed separately, so that they are 
liable to slight misplacement, sometimes making streams and contour lines disagree in 
their positions. These contours not only show the place, shape, and height of separate 
mountains and hills, but permit a comparison of their heights above the sea and in rela- 
tion to each other throughout the whole state. For convenience in such comparison, 
the lines of 500, 1,000, 1,500 feet, etc., above the sea are dotted, and their heights fre- 
quently marked, while the other lines are continuous and unmarked. 

The eastern part of Rockingham county, and the portion of Essex county, Mass., 
which comes within the limit of our map, being occupied more or less fully by the re- 
markable lenticular hills of glacial drift, have received special attention. Contour lines 
are shown upon these areas for each 50 feet, those marking heights 100, 200, and 300 
feet above the sea being continuous lines, while those intermediate are dotted. The 
Ammonoosuc mining district has been surveyed by Mr. John N. McClintock, whose 
map with contour lines for each 10 feet is presented in Part V of this report. Besides 
these, the White Mountain district has perhaps been as well represented as any other 
portion of the state; but many of the smaller peaks, ridges, spurs, and ravines remain 
to be explored and mapped in this region. It is hoped that our efforts to show the 


ALTITUDES, CONTOUR LINES, AND RAISED MAPS. 347 


form of the surface of New Hampshire by these lines will serve to call the attention of 
our people to the value of such work, and ultimately lead to a detailed topographic sur- 
vey and map. 

"The same information respecting the altitude and contour of the whole state, which 
is shown by these lines on the maps in the atlas of this report, has been otherwise and 
more noticeably displayed by a model or raised map of New Hampshire, the original of 
which has been placed in the vestibule of the state-house at Concord. The museum of 
Dartmouth college has a copy moulded from this, and others might be easily made. It 
will be seen, however, that the construction of the first model, to show all our principal 
mountains, hills, and valleys, involves a large amount of painstaking labor. This re- 
lief has a scale of one inch to a mile in distance horizontally, and of one inch to 1,000 
feet in height, making it about fifteen feet long, with Mt. Washington a little more than 
six inches high. The elevation is five times too great, as compared with the extent,— 
this exaggeration being necessary to give any prominence to the numerous hills less 
than 1,000 feet in height. 

A map on the horizontal scale of the proposed model was first drawn, by enlargement 
from the draft of the new state map, with contour lines for each 500 feet above the sea. 
Tracings of these lines were then made and transferred to boards of pine or basswood 
half an inch in thickness, corresponding on the scale of height to 500 feet. The boards 
were then sawed to the irregular form of the successive contours. Upon each set of 
boards, the line next above that followed in sawing was also drawn, and showed the 
exact position to be occupied in placing them one upon another to build up the high- 
lands and mountains. The projecting upper edges of the layers of board were then 
bevelled to a continuous slope, or cut into the hills and valleys required by intermediate 
lines of contour. The surface is painted, showing township lines, streams and ponds, 
railroads, etc., with their names, and those of villages and mountains. 

In the study of the modified drift, a large amount of levelling has been done, princi- 
pally along Connecticut and Merrimack rivers. The heights of all the terraces in both 
these valleys north of the Massachusetts line have been accurately determined, and are 
shown on Plates I-VI of this volume. Heights of these rivers and of localities near 
them were also determined, and are given, with the elevation of the highest terraces, 
on pages 39, 59-61, and 102 and 103. The most important corrections from altitudes 
along these rivers, published in Volume I, are in regard to the height of a portion of 
Connecticut river, which at Brattleborough is 200, at the mouth of Ashuelot river, 185, 
and at Massachusetts line, 180 feet above the sea (corrected from Vol. I, pp. 304 and 
319) ; and the height of Pemigewasset river at the mouth of the east branch, which is 
710 feet above the sea (corrected in this volume, p. 70, from Vol. I, pp. 288, 308, and 
322). The height of Winnipiseogee lake obtained by levelling (pp. 103 and 125) sug- 
gests the possible need of a still more important correction to be applied to nearly all 
the connected series of altitudes determined by railroad surveys in the western and 
northern parts of the state, published in Chapter X of Volume I. These altitudes 
may be said to be reckoned from Concord depot as a starting-point, which appears 


348 APPENDIX TO PARTS I AND II. 


upon good evidence to be 16 feet higher than was formerly supposed (see Vol. I, pp. 
250-252). Referred to this datum, however, the height of Winnipiseogee lake appears 
to be 11 feet above that obtained by the survey for the Portsmouth, Great Falls & Con 
way Railroad (Vol. I, p. 265). One of these determinations of the level of the lake 
must be incorrect. Heights along Contoocook river and on streams in Antrim, with 
corrections to be made in Volume I, page 268, are stated in this volume on pages 102 
and 119; heights along Salmon Falls river, on page 150; and in Dover, on page 156. 
Mr. George L. Whitehouse, of Farmington, informs us that the height given in Volume 
I, page 264, for the summit between Alton and Farmington, refers to the highest point 
of the railroad, while the greatest depth that would have to be cut through to turn Win- 
nipiseogee lake into Cochecho river is only 28 feet, which calls for a correction on page 
129 of this volume. 

To the tables of altitudes previously published, we append a few additional observa- 
tions, principally in the mountain region: 


HeicutTs 1n THE Wuitz Mountain District. 
From barometric measurement in 1876 and 1877 by Prof. F. W. Clarke: 


On the Mt. Washington Range. Mt. Starr King (Prof. C. R. Cross), 3925 


Nelson crag, north of Huntington’s ra- Mt. Adams house, 1648 
vine, j ; 5615 Boy mountain, 2278 
South wall of this ravine, 5432 Randolph hill, 1518 
Lion’s Head, north of Tuckerman’s ra- Jefferson Mills bridge, 1022 
vine, 5016 Bridge at Stag hollow, 1380 
Boott’s spur, é 5524 Israel’s River bridge, Cherry os 
Foot of Mt. Adams path, 1430 tain road, 1085 
Camp of Appalachian Mountain Club, Owl’s Head, spur of Cherry mount., 3302 


Mt. Adams, 3307. Farmhouse at the foot of Owl’s Head 
First bald ledges on this path, 4342 path, 1442 
Cliff at head of King’s ravine, 5125 Bray hill, 5 1637 
Summit of Mt. Adams (Guyot), . 5794. Mt. Prospect, Lancaster, 2062 
Samuel Adams peak, nearly 4 mile Mt. Pleasant, ae 1896 

west, 5554 Road between these, . 1447 
John Quincy Rance peak, % mile Farmhouse at the foot of path up > Mt. 

north, 5384 Prospect, 1310 


Nowell’s peak, a little more than 4 
mile north-west, 


Summit of road from Jefferson to the 


5313 Twin Mountain house, 1676 


Star lake, between Adams and Madi- 
son, 4890 
Heights near Fefferson. 


Starr King house, 1437 


Lunenburg heights, Vt. (Prof. C. R. 
Cross), 1618 


Heights in Bethlehem and Whitefield. 
Sinclair house, . 1459 


ALTITUDES, CONTOUR LINES, AND RAISED MAPS. 


Maplewood house, 
Dodge’s, Whitefield, 1279 
Fiske’s, tie : 1250 
On road from Whitefield to Bethlehem: 

Railroad crossing, 


1489 


1109 


Ammonoosuc bridge, IlIg 


1305 
Summit of stage-road by Mt. Agassiz, 1840 
« upper stage-road from Beth- 

lehem to Franconia, 1913 
Wallace hill, Bethlehem, 2124 


Summit of road, 


Heights near Franconia. 
Summit of road between Littleton and 


Franconia, ‘ 1360 
Bridge, Franconia Iron Works, . g20 
Lafayette house, 999° 
Franconia house, 1054 
Profile farmhouse, 1302 
Bald mountain, . 2310 


Notch on Lafayette path by Eagle cliff, 2990 
Clearing between Profile and Flume 
houses, 1772 
2750 
1895 
1351 
from a recent 


Moran or Lonesome lake, . 
Summit of Sugar hill, Lisbon, 
Sugar Hill post-office, 
Ossipee Mountain, 
barometric measurement of Prof. C. 
R. Cross, is found to have a height 
of 2950 feet, instead of that given in 
Volume I, page 280. An eastern 
peak of this mountain is, by the 
same authority, 2774. 


VOL. III. 45 


349 


HEIGHTS IN CHESHIRE COUNTY. 
In Section II, Volume I, page 284, 
correct the height of bridges in 
Swanzey by subtracting 550 feet. 
From levelling by George W. Sturte- 
vant, of Keene: 
Goose pond, Keene, source of city 


water-works, ; 638 
From levelling by J. J. Holbrook, of 
Keene: 
Beech Hill reservoir, 595 
Summit of Beech hill, 1060 
Also from Mr. Holbrook’s levelling, 
Troy station being taken as 1002 
(Vol. I, p. 259): 
Troy school-house No. 3, lowest 
step, 4 1166 
Jaffrey school- Regie No. 12, thresh- 
old, 1231 
John Mann’s house, 1488 
Monadnock Mountain house, . 2072 


Summit of Monadnock mountain, 3169 
(Compare with Vol. I, p. 279). 
From levelling by A. P. Little, of 
Keene: 
Swanzey, Sawyer’s crossing, R. R. 


bridge, : 485 
West Swanzey, oa 4953 ae 

uelot river above dam, 461; be- 

low dam, 454 


350 APPENDIX TO PARTS I AND II. 


APPENDIX ¢. 


APPENDIX TO THE CATALOGUE OF THE PLANTS OF NEW HAMPSHIRE, 


The number of plants known to grow without cultivation within the limits of the state 
has been somewhat increased since the publication of Volume I. These additions to 
the catalogue of that volume (pp. 395-414), together with those found in its appendix, 
are here presented, marked with letters and signs which are there used and explained, 
indicating distribution, relative abundance, and introduced species. 

A paper on the ‘Distribution of Plants in New Hampshire and Vermont,” by Will- 
iam F. Flint, occurs in the American Naturalist, Volume XI, pages 89-95. The flora 
of the White Mountains has been described by Edward Tuckerman, in T. Starr King’s 
White Fills, pages 230-241; and by J. H. Huntington in Appalachia, Volume I, pages 


100-106. 
POPPY FAMILY. Poterium Canadense. Burnet. . oo 
Papaver Rheas. Corn Poppy. Near the coast. 
Hanover. Pyrus arbutifolia; var. erythrocarpa. 


MUSTARD FAMILY. var. melanocarpa. 


Dentaria maxima. SAXIFRAGE FAMILY. 


Near Bedell’s bridge, Haverhill. Mitella nuda. 
Arabis perfoliata. : ; Hanover. 
Fields ae Connecticut river. PAT RCREC, RARER. 
Be sf calegeee Aneetiartaiver near Proserpinaca palustris. Mermaid- 
White River Junction. weed. 
PINK FAMILY. LOOSESTRIFE FAMILY. 
Cerastium vulgatum. Lythrum Hyssopifolia. . . ay 
Spergularia media. . ‘i Fi « PARSLEY FAMILY. 
VINE FAMILY. Ligusticum Levisticum. Lovage. 


Around old dwellings. 


Vitis cordifolia; var. riparia. ae : 
Zizia integerrima. 


MILKWORT FAMILY. 
HONEYSUCKLE FAMILY. 


Polygala cruciata. F F 


Near the coast. Lonicera parviflora. 


Connecticut valley. 

PULSE FAMILY. 
Colutea arborescens. COMOSINE FAMILY. 
Growing together at Eupatorium teucrifolium. 


tea" — Sumner’s” Falls, E. pubescens. 
Haingeld. Sericocarpus solidagineus. 


Vicia tetrasperma. aN, 
2 Aster tenuifolius. 


ROSE FAMILY. 
A. carneus. 


Prumus maritima. Beach Plum. 4 * , 
Near the coast; also on the upper A. Nove-Angliz. 
terrace west of Amoskeag falls. Solidago stricta. 


APPENDIX TO THE CATALOGUE OF PLANTS. 


S. patula. 

Ambrosia trifida. 

Bidens bipinnata. 

Anthemis arvensis. Corn Chamomile. 
Artemisia vulgaris. Mugwort. 


Onopordon acanthium. Scotch Thistle. 


Cynthia Virginica. 
HEATH FAMILY. 


Leucothoé racemosa. . 
Near the coast. 


Chimaphila maculata. 
Seabrook. 


Pterospora Andromedea. Pine-drops. 
Hanover. 


BLADDERWORT FAMILY. 


Utricularia purpurea. 
Winchester. 


U. resupinata. 
Pinguicula vulgaris. 
Mt. Willard. 
BROOM-RAPE FAMILY. 
Aphyllon uniflorum. Cancer-root. 
FIGWORT FAMILY. 


Veronica peregrina. 
Fields in Connecticut valley south 
of Bellows Falls. 


Gerardia purpurea. 
Near the coast. 


G. maritima. 


MINT FAMILY. 


Monarda fistulosa. Wild Bergamot. 
Rockingham county. 


Galeopsis Ladanum. 
Hanover to Hinsdale; rare. 


GENTIAN FAMILY. 


Gentiana quinqueflora. 
Hanover. 


Bartonia tenella. 
DOGBANE FAMILY. 
Apocynum cannabinum ; var. hyperici- 
folium. 
AMARANTH FAMILY. 
Amarantus hypochondriacus. 
A. shinosus. 


BUCKWHEAT FAMILY. 
Rumex salicifolius. White Dock. 2 
R. maritimus. Golden Dock. 


OAK FAMILY. 


Quercus bicolor. Swamp White Oak. 
Low’r Merrimack valley and Rock- 
ingham county. 


Q. Primus; var. humilis. Dwarf Chin- 
quapin Oak. 
Same range as the last. 
WILLOW FAMILY. 


Salix tristis. 
Lower Merrimack valley. 


S. nigra; var. falcata. 
PINE FAMILY. 


Cupressus thyoides. White Cedar. 
Manchester, and near the coast. 


ARUM FAMILY. 


Peltandra Virginica. Arrow Arum. 
Walker’s pond, Conway. 


DUCKWEED FAMILY. 
Lemna polyrrhiza. 


CAT-TAIL FAMILY. 
Sparganium simplex; var. androcla- 
dum. 
ORCHIS FAMILY. 


Spiranthes Romanzoviana. 
Bogs ; New Hampton. 


Pogonia pendula. 
Winchester. 


IRIS FAMILY. 
Iris Virginica. 
Near the coast. 
RUSH FAMILY. 
Juncus militaris. 


SEDGE FAMILY. 
Eleocharis pygmza. 
Scirpus polyphyllus. 
S. lineatus. 
Rhynchospora capillacea. 
Carex siccata. 
C. Emmonsii. 
C. Kneiskernii. 


C. polymorpha. 


351 


352 APPENDIX TO 


C. Houghtonii. 
Franconia. 


GRASS FAMILY. 


Calamagrostis Nuttalliana. 
Hampton. 
Spartina cynosuroides. 


Poa cesia. 
Summit of Mt. Willard. 


Bromus Kalmii. 


Hierochloa borealis. 
Hanover and Amherst. 


PARTS I AND IL 


Panicum virgatum. . A ‘ g * 


Near the coast. 


P. pauciflorum. 


HORSETAIL FAMILY. 


Equisetum scirpoides. 
Along Connecticut river. 


CLUB-MOSS FAMILY. 
Isoetes echinospora; var. Braunii. 
I. riparia. 


CATALOGUE OF THE Mosszs AND LiIvERWoRTS oF NEw Hampsnuire. 


The nomenclature is that of Sullivant’s Musee and Hepatice, from which the 
species found upon the White Mountains (designated by M) are compiled. The 
others have been collected in the vicinity of Hanover by William F. Flint and Ed- 
ward Hyde, or in the south-west part of the state by Charles C. Frost, the distin- 


guished cryptogamic botanist, of Brattleborough, Vt. 


star (*). 


MOSSES. 


Sphagnum cymbifolium. . ‘ gh 

S. Lescurii. 

S. sedoides. 
Ethan’s pond. 

S. squarrosum. 

S. acutifolium. 

S. cuspidatum. . ‘ . , a 

Andreea rupestris. : 5‘ ‘i 7 

A. crassinervia. . 

Phascum serratum. 

P. cuspidatum. 

P. Sullivantii. 

Gymnostomum curvirostrum. . o 

G. rupestris. 

Weisia viridula. . ‘ ‘ i 

Rhabdoweisia fugax. . 

Arctoa fulvella. 

Dicranodontium longirostre. 

Trematodon longicollis. . . 2 


Dicranum gracilescens; var tenellum. M 
* 


ZE x 
RY RY AY fy 


D. varium. . 
D. rufescens. . : re 4 oe 


Commonness is indicated by a 


.subulatum. . ‘ 
. heteromallum. ‘ - . ‘ 
. Blyttii. 

. Starkii. . 

. flagellare. 

. interruptum. 
. longifolium. 
. scoparium; var. pallidum. . aad 
. undulatum. 


emo momemomomemomem©) 


. Drummondii. 
Ceratodon purpureus. s ‘  * 
Leucobryum glaucum. : . oe 
L. minus. 

Fissidens minutulus. 

. bryoides. 

. osmundiodes. ‘ , ' ae 
. subbasilaris. 

. taxifolius. 

. adiantoides. . ‘ ‘ weeks 
Conomitrium Julianum. 

Trichostomun pallidum. 

Barbula unguiculata. 

B. czspitosa. 


APPENDIX TO CATALOGUE OF PLANTS. 


B. convoluta. 

B. mucronifolia. . 
Pottia truncata. 
Tetraphis pellucida. 


Tetrodontium repandum. 
Near the Glen house. 


Encalypta ciliata. 
Hanover. 


Zygodon Lapponicus. 
Z. Mougeotii. 
Drummondia clavellata. 


Orthotrichum obtusifolium. 


. Strangulatum. 
. Canadense. 

. Ludwigii. 

. Hutchinsiz. 

. crispum. 


© .©O:- OC OO: 0 


. Bruchii. 
Ptychomitrium incurvum. 
Schistidium apocarpum. 
S. confertum, var. 
Grimmia Olneyi. 

G. Pennsylvanica. 

G. Donniana. 
Racomitrium aciculare. 
R. lanuginosum. 

R. fasciculare. 


R. ellipticum, Br. and Sch. 


R. canescens. 
Hedwigia ciliata. 
Diphyscium foliosum. . 
Atrichum undulatum. 
A. angustatum. . 

A. crispum. 
Pogonatum brevicaule. 
P. urnigerum. 

P. capillare. 

P. alpinum. 
Polytrichum commune. 
P. formosum. 

P. juniperinum. . 

P. piliferum. 


*S 58 


Aulacomnion heterostichum. 


A. palustre. 

A. turgidum. 
Bryum pyriforme. 
. crudum. 

. nutans. 

. cucullatum. 
roseum. . és 
. Wahlenbergii. 
. argenteum. 

. pseudo-triquetrum. 
. alpinum. 

. bimum. . 

. capillare. 


DH ndndddonoonooos 


. cespiticium. 

Mnium affine. 

M. hornum. 

. Stellare. 

. cCinclidioides, Hedw. 
. punctatum. 


M 

M 

M 

M. Drummondii. 
M. rostratum. 
M. cuspidatum. . 

M. spinulosum. . 
Meesia uliginosa. 
Bartramia ithyphylla. . 
B. Oederi. 

B. pomiformis. 

B. fontana. 
Conostomum boreale. . 


Funaria hygrometrica. 
yer 


Physcomitrium pyriforme. . 


Tetraplodon angustatus. 
Fontinalis antipyretica. 
F. Eatonii, Sulliv. 

F. disticha. 


353 


es 


* 


Saco river in White Mountain Notch. 


F. Lescurii. 

F. Frostii, Sulliv. 

F. Dalecarlica. 
Dichelyma falcatum. . 
D. capillaceum. . 


« & 


354 APPENDIX TO PARTS I AND II. 


Leucodon julaceus. 

Leptodon trichomitrium. 
Anomodon viticulosus. 

A. tristis. 

Leskea obscura. . 

L. rostrata. 

L. nervosa. 

Clasmatodon parvulus. 
Thelia hirtella. 

T. asprella. - 
Anacamptodon splachnoides. 
Palaisza intricata. . 
Homalothecium subcapillatum. 
Platygyrium repens. 


Pterigynandrum filiforme, Hedw. 


Cylindrothecium cladorrhizans. 
C. seductrix. 

Neckera pennata. 

N. bifida, James. 

White Mountain Notch. 
Omalia Jamesiana. 
Climacium Americanum. 
Hypnum tamariscinum. 

. delicatulum. . 
scitum. . 

. abietinum. 

. paludosum. 

. triquetrum. 

. brevirostre. 
splendens. 
umbratum. 
Oakesii. 

. Alleghaniense. 
. Strigosum. 

. serratulum. 
rusciforme. 
recurvans. 
demissum. 

. cylindricarpum. 
eugyrium. 


. palustre, L. 


* 


* 
Toot ertaeeg 


* 


pe pS hE BB Bt mt mt mt mt ont ot 


* 


* * * Xx 


* 


* 


*s 


* * * 


* 


. ochraceum. 

+» montanum. 

. cuspidatum. . 
. Schreberi. 

. cordifolium. . 
. stramineum. . 
. uncinatum. 

. fluitans. 

. aduncum. 


Ethan’s pond. 


Crista-Castrensis. . 
. cupressiforme. 


imponens. 
reptile. . 
curvifolium. . 
Haldanianum. 
nemorosum. 
pratense. 
salebrosum. 
letum. . 
rutabulum. 
plumosum. 
populeum. 
reflexum. 
Starkii. . 


. Nove-Anglie. 
. Stellatum. 
. polymorphum. 


hispidulum. 
dimorphum. 
Ellis river. 


. subtile. 


adnatum. 
serpens. 
radicale. 


. orthocladon. . 
. riparium. 

. Lescurii. 

. denticulatum. 
. Muhlenbeckii. 
. sylvaticum. 


se 8 


* eS x & 


* #£ # K® * 


SB * « & * 


* 


* 


* 


APPENDIX TO CATALOGUE OF PLANTS. 


H. elegans. , 


LIVERWORTS. 
Riccia natans. 
R. fluitans. 
Anthoceros punctatus. 
A. levis. a 2 
Marchantia polymorpha. 
Fegatella conica. 


Reboulia hemispherica. . 


Fimbriaria tenella. 
Mentzgeria furcata. 
Aneura palmata. 

A. multifida. 

Pellia epiphylla. 

Blasia pusilla. 
Chiloscyphus polyanthos. 
Lophocolea bidentata. 
Sphagneecetis communis. 
Jungermannia trichophylla. 
. setacea. . ‘ 2 

. connivens. 

. curvifolia. 

. bicuspidata. 

. divaricata. 


ey ye ey 


. setiformis. 


._M 


a 


* * 


* * 


* 


* 


Ss * 


J. barbata. . 

. intermedia. 
. Schraderi. 

. Taylori. 

. crenulata. 


ey ey ey 


- exsecta. . 

Scapania nemorosa. 
Plagiochila spinulosa. 

P. asplenioides. . 

P. porelloides. . ‘ 
Sarcoscyphus Ehrharti. 
Gymnomitrium concinnatum. 
Frullania Grayana. 

F. Tamarisci. . ‘ g 
F. Virginica. 

F. Eboracensis. . 

Lejeunia cucullata. 
Madotheca platyphylla. 
Radula complanata. 
Ptilidium ciliare. 
Trichocolea Tomentella. 
Mastigobryum trilobatum. . 
Lepidozia reptans. 
Calypogeia Trichomanis. 


APPENDIX D. 


THE RELATION OF GEOLOGY TO DISEASE, 


By G. W. Hawes. 


355 


Mr. J. T. Gardner, in his address before the American Public Health Association at 
Boston,* has drawn attention to the intimate connection between geology and health. 


He indicates that controlling causes of some of our most fatal diseases are to be found 


in local structural and lithological conditions, which are of even greater weight than 


the condition of the air. In some regions above the palisades of the Hudson malarial 


diseases are very prevalent. This region is underlaid by dense basaltic rocks, through 


* Boston, October 6, 1876. 


356 APPENDIX TO PARTS I AND II. 


which water cannot percolate, but is accumulated in basins beneath the surface, there 
to become stagnant and breed disease in a high region which has pure clear air and ap- 
parently all the conditions for the best of health. Many cases are cited; among which 
is one of interest to us, as it shows that considerations of this kind are worthy of closest 
attention in New Hampshire. The case is derived from the study of the geological 
conditions in the town of Greenland, N. H., and is quoted from an article by Dr. Henry 
J. Bowditch on ‘‘ Consumption in New England, and locality one of its chief causes.” 

Dr. Bowditch thinks that the most powerful agent in promoting the disease called con- 
sumption is the soil moisture which results from the structure of the country and the 
character of its soil and underlying rocks. In Greenland there are three distinct varieties 
of soil:—1. A high and dry sandy plain. 2. A middle fertile and rather moist portion. 
3. Extensive low marshes. Between these three portions the inhabitants, 715 in num- 
ber, were about evenly divided; and yet, in a given length of time, there were three 
deaths by consumption on the sandy plains, five in the middle moist region, and ten in 
the lowlands, or three times as many in the wet as in the dry region. But in a town 
in Maine the conditions were exactly reversed: the lowlands were of porous gravel, 
while the highlands were clayey and impervious to moisture. Here, ina given length 
of time, the number of deaths was two times larger on the Aigh/ands than on the low- 
lands. 

These cases indicate that the character of the rocks, and their mode of arrangement, 
are important elements in the control of health or disease, and that the character of 
our rocks and the mode of arrangement, which have been described at such length in 
these volumes, have an important influence on the duration of human life. They indi- 
cate that the crystalline condition, the schistose or compact structure, the geological 
arrangement of rocks, and all those characters of rocks and soils which facilitate or 
impede drainage, are powerful influences in determining local conditions for health, 
and that, therefore, the lithology and geological structure of their special region should 
bea study of each member of the medical profession. 


APPR ILE Be. 


NOTE ON SOME POINTS IN THE GEOLOGY OF STODDARD AND MARLOW, 
CHESHIRE COUNTY, N. H. 


By SANBoRN TENNEY. 


The prevailing rocks in this region are gneissoid and mica slate. Their strike is 
north-easterly, being north 30°-40° east by the needle, and they dip easterly at a high 
angle, in many places 60° or more. In some places, as near Stone pond, in Marlow, 


GEOLOGY OF STODDARD AND MARLOW. 357 


the bedding is exceedingly well defined, so that the effect is very beautiful, especially 
as dark and light colors alternate more or less with one another. 

The whole region gives the most ample evidence that it was once subjected to long 
continued glacial action. The rocks are planed down and grooved, and boulders in 
many places almost cover the ground over areas miles in extent. Probably there are 
but few places, if indeed there are any in our country, where the boulders are more 
numerous than in this part of New Hampshire. Between Hancock and Marlow, inclu- 
sive, the boulders are, in a great majority of cases, porphyritic granite. In the vicinity 
of South Stoddard, some of the boulders are of enormous size. One boulder, not far 
from the road, and on the right hand in going from the ‘‘ Box tavern” to Stoddard 
village, is about fifty paces in circumference, and probably contains 40,000 cubic feet 
of rock. Many others in the vicinity approximate this in size. Another of very great 
size is found about half a mile from the village of Marlow, in a southerly direction, and 
just east of the Ashuelot river. 

Rocking-stones are not uncommon in this region. Two beautiful examples of this 
kind are found in Marlow, not far from a place in the Ashuelot river well known as the 
‘‘Bend.” Several of these stones are found on a hill westerly from the Abbot pond, 
which is on the right hand of the main road leading from Stoddard to Marlow. But I 
hasten to say that not one of these last will now ‘‘rock,” for they have been tipped 
and wedged up by stones, put in by the farmers, as I learned, under the impression 
that the flocks and herds might be injured by them. I believe that an ox, or some 
other creature of the farm, did get caught by the tipping of one of these boulders, and 
this fact led to the wedging of them so that they could not rock. We examined them, 
and satisfied ourselves that they would rock again as soon as these props or wedges 
were removed. 

The drift striz in Marlow are nearly due north and south, varying only slightly from 
a due northerly and southerly course, as the needle points. The effect produced by 
the planing down of the highly inclined slate near Stone pond is very interesting and 
beautiful. Not a projecting point is left, and the bare, clean, and smoothly planed 
edges of the dark- and light-colored layers of the gneissoid rocks present a very strik- 
ing and beautiful appearance to the eye of the geologist. 

Very near the outlet of Stone pond are very beautiful examples of granite dykes in 
the gneissoid rocks, some crossing others, and thus showing that they were formed at 
different times. Northerly from Stone pond, at a distance of a mile or less, is Trout 
pond, interesting from the fact of its being nearly surrounded by high hills of drift. 
One large moraine is, as it were, cut off by the pond; the moraine continues for a 
considerable distance northerly and southerly, interrupted only by this pond. How 
this pond was formed in the line of this moraine, is an interesting question. Was the 
pond there before the moraine? If so, why was it not filled by the drift material? Is 
it not probable that the age of the pond dates from the glacial period, and that there 
was a vast accumulation of ice just where this pond is to-day? 

VOL. 111. 46 


358 APPENDIX TO PARTS I AND IL 


APPENDIX F. 


GEOLOGY OF THE REGION ABOUT THE HEAD WatTERS oF THE ANDROS- 
coGcGIn River, Me. 


By J. H. Hunrineron. 


If we examine a map, and look at the western part of New Hampshire, we see that 
Hall’s stream, one of the principal branches of the Connecticut river, has a part of its 
branches in the province of Quebec; then eastward, all the streams as far as the St. 
John’s in Maine have their waters wholly in the states. Of the streams included in 
this area, Indian, Perry’s, the Connecticut, the Magalloway, the Cupsuptic, the Kenne- 
bago, Dead river, and Moose river, I have followed from their sources to their conflu- 
ences with other waters; and, besides this, I have traversed much of the intervening 
country. As a continuous forest extends along the north-western border of Maine, 
geological work is slow and extremely laborious. The topography of the country is 
somewhat peculiar. The boundary itself is a mountainous ridge, rising from 2,500 to 
3,000 feet above the sea, and it is extremely irregular in outline. The streams from 
Hall’s to Dead river have a course almost due south; then to the north-east the streams 
at first all begin their courses by flowing northerly and north-easterly. The glaciation 
of the continent, and the trend of the strata of the rocks, have given in part, at least, 
this peculiar feature to the streams of this region, though there is no doubt but that 
the great depression of the St. Lawrence valley is the primal cause. 

The area of country to which this paper relates more specifically borders on the Cup- 
suptic and Kennebago rivers. Both of these streams rise on the boundary. On the 
first, three fourths of a mile from the boundary, the beavers, by building a dam, have 
formed quite a little lake. This is 600 feet below the highest point of the ridge. For 
five miles in a direct line the stream is sluggish, and is frequently interrupted by beaver 
dams ; then for half a mile it cuts a deep gorge through an argillaceous schist, and has 
a fall of some thirty feet; then for six or seven miles it has very much the same char- 
acter that it has above the gorge; then for nearly a mile it rushes along in a series of 
wild cascades, while here and there it plunges down into great eddies, when it rests 
only to leap again over the rocky strata below. The falls passed, it assumes again its 
sluggish character, which it retains until it flows into Cupsuptic lake. The entire length 
of the stream in a direct line is about 13 miles. The Kennebago is quite a different 
river. On the boundary rise numerous streams, which widen into lakelets, and then 
flow southward until they unite in No. 4 R. 3. Then the descent is quite gradual until 
after it passes Kennebago lake,—then there are extensive falls; thence for the most 
part the descent is gradual for the rest of its course. There are some things about the 
topography that are quite noticeable. From a point a mile south of the outlet of Ken- 
nebago lake a range of mountains begins, which runs north-west, and extends to the 


HEAD WATERS OF THE ANDROSCOGGIN. 359 


Cupsuptic. On the Kennebago, the rock is fissile slate; on the Cupsuptic, the rock is 
an argillaceous schist; but the summit, at least of the north-west peak, is granite. 
From the point where the streams unite in No. 4 R. 3, a range of mountains on the 
west side of the Kennebago runs north-west; and on the east side of the river a range 
runs north-east. Between these ranges are the streams mentioned above as widening 
into lakelets. 

The area about the lakes was briefly mentioned by Prof. C. H. Hitchcock in the re- 
port of the scientific survey of Maine for 1862. 

The conglomerate found at the outlet of Rangeley lake has been described by Prof. 
Geo. L. Vose. Some notes on the geology of the area north-east of Kennebago river 
were presented at the Portland meeting of the American Association for the Advance- 
ment of Science. The rocks found on the west of the Cupsuptic have been described 
by me at some length in the report of the geological survey of New Hampshire (Vol. 
II). As I understand the rocks, the following formations are represented : 


I. STRATIFIED GROUPS. 


Gneiss. 
; 

Gneiss containing limestone. 
lL 


LauRENTIAN. 


White Mountain gneisses and schists. 
Mica schists with staurolite. 

Chloritic and whitish argillitic mica schists. 
Sandstone schists. 

Diabase. 


Huronran, 
eu 


Diorite with serpentine. 
Argillitic mica schist with staurolite. 
Rangeley conglomerates. 


Wrinkled argillaceous schists with hard micaceous bands. 
; Slaty conglomerates. 


Pauzozoic. 


Calcareous sandstones with fossils. 


(Glacial drift. 
| Media drift, including kames, etc. 


Cenozoic. 


II. Eruptive Rocks. 


Granite (Conway). 
Diorite. 
Felsite. 


Gneiss. The area of gneiss is very small, and it was seen only on the boundary on 
the head waters of the north-west branches of the Kennebago river. It is a fine-grained 


360 APPENDIX TO PARTS I AND IL. 


rock, and the outcrops were so few that the dip could not be well determined. Asan 
intrusive granite and a fine-grained diorite were the only rocks seen in the vicinity, its 
stratigraphical relations have not been satisfactorily determined; but its resemblance 
to the Laurentian gneiss in the vicinity of the chain of lakes to the north-east makes it 
altogether probable that it is a part of the Upper Laurentian. 

Gneiss with Limestone. Approaching the lake region from the east at the village of 
Phillips, we find an intrusive granite that is somewhat coarser than the common Con- 
cord granite. It extends a mile east of the village. On Sandy river, where the road 
crosses the river for the first time above Phillips, we find the intrusive character of the 
rock clearly seen, as here great masses of schist have been caught in it; and elsewhere 
the granite appears only as veinstones in the schist. About two miles above the village, 
on the north side of the river, there is a fine-grained micaceous gneiss that has inter- 
calated beds of a dark limestone: this at some time has been burned for lime. The 
whole breadth of country occupied by this gneiss does not here exceed a mile. The 
stratum is very irregular in strike, and has an inclination of 30° to 50°. 

fluronian—White Mountain Gneisses and Schists. These rocks, which belong to 
the Montalban series of the New Hampshire geological survey, are found north-west of 
the outlet of Moosetocmaguntic lake. The strata here have nearly an east and west 
strike, and are vertical; but this is probably due to a great mass of intrusive granite 
between this and the river that joins the lakes on the south. The lithological charac- 
ter of the rock is similar in every respect to the rocks found in the vicinity of Mt. Wash- 
ington, and it is probably a continuation northward of the rocks so extensively devel- 
oped along the Androscoggin river in Gorham, N. H., and eastward. This is near the 
northern limit of these rocks in the area we have studied. 

Mica Schists with Staurolite. South of Moosetocmaguntic lake, in townships D and 
E, and extensively developed in the town of Byron, is a series of rocks consisting of 
fine-grained, thick-bedded mica schists that carry staurolite. These schists, wherever 
observations were made, have a dip almost directly north; and the inclination does not 
usually exceed 45°, especially northward. From the south, they follow directly on the 
White Mountain gneisses. 

Chloritic and Whitish Argillitie Mica Schists. North of the rocks last mentioned, 
and east of the White Mountain gneisses, near the northern part of Moosetocmaguntic 
lake, and extending east beyond the outlet of Rangeley, there is a series of rocks con- 
sisting chiefly of chlorite and whitish argillitic schists. They are noticeable on account 
of their unconformability with the rocks east and south, and the abundance of quartz 
which they contain, and which lies in the line of the stratification. This rock forms 
ledges at Frye’s Camp, at Houghton’s Camp, and on the ridge immediately south of 
the Mountain View house at the outlet of Rangeley lake. 

Bald mountain, an isolated peak between Rangeley and Moosetocmaguntic lakes, al- 
though chiefly granite south of the ridge just mentioned, has upon its top a great mass 
of this schist, which was caught in the granite. Indian Rock, at the mouth of Kenne- 
bago river, and famed in the annals of fishermen, is a wonderfully contorted argillite, 


HEAD WATERS OF THE ANDROSCOGGIN. 361 


and may possibly belong to a different series of rocks. The hill immediately north of 
Cupsuptic lake is a light gray argillitic schist. The strata are nearly everywhere verti- 
cal, and the strike is N. 40° E. Northward along the river there is no outcrop of rocks 
for several miles; but at the falls of the Cupsuptic a rock similar to the last is found. 
It differs from it in being of a darker color, somewhat more siliceous, and weathering 
with a pitted surface near where it comes in contact with an intrusive granite. Having 
seen a similar change elsewhere in the same kind of rock, under the same circum- 
stances, it is more than probable that the granite was in some measure the cause of 
the change. 

Sandstone Schist. Three miles north of Kennebago lake, on the Kennebago river, 
we find a sandstone schist. Although it often resembles a mica schist, yet nearly every- 
where there is no doubt as to the character of the rock; and in some localities the frag- 
ments of which it is composed are a quarter of an inch in diameter, and very distinct, 
especially on the weathered surface of the rock. Elsewhere it has been greatly changed ; 
and in some localities we find crystals of feldspar that have been produced since the 
sedimentation of the rock. This sandstone extends northerly some eight miles along 
the Kennebago river. On the mountain ridge north of Kennebago lake, where the 
sandstone first appears, the strata are nearly vertical, and the strike is N. 70° E.; but 
along the river the strike is more northerly. South of this great area of rock we have 
red and light gray argillites, and on the north we have diorite with serpentine. This 
sandstone schist is the rock on the boundary at the head waters of the Cupsuptic 
river, and it extends at least three miles southward along that stream; and the same 
rock outcrops on the Magalloway at Little Boys’ falls north of Parmachena lake,—so 
that the area of this rock is exceedingly irregular in outline. 

North-west of Kennebago lake, and extending south below the falls on the Kenne- 
bago river, there is an area of light gray, dark purple, and red argillites. The strata 
are vertical where observations have been taken; and there are sudden changes from 
one variety to the other. These argillites are probably the finer sediments derived from 
the great mass of material from which the sandstone schists were formed. 

Diabase and Diorite with Serpentine. Diabase occupies an area on the Kennebago 
river. The most northern outcrop is abouta mile from its mouth, and it extends a 
mile and a half northward along the river, and eastward towards Quimby pond. It is 
not altogether certain that this is a metamorphic rock. If only the southern outcrop 
had been seen, and the rock had been studied only in the field, we could have reached 
no other conclusion than that it was intrusive, yet other outcrops strongly indicate that 
the rock is metamorphic. At the head of one of the north-west branches of the Ken- 
nebago, which rises near the point where the boundary extends farthest southward, 
there is a fine-grained greenish rock, which would probably be distinguished as mela- 
phyre by the German geologists. The area is limited here; but there are extensive out- 
crops on the boundary of New Hampshire, the summit of Mt. Carmel being composed 
of similar rock. The metamorphic diorite is one of the most interesting rocks found 
in this section of Maine. It outcrops on the Kennebago about twelve miles north of 


362 APPENDIX TO PARTS I AND II. 


Kennebago lake. Very few ledges are seen. The boulders, however, are large and 
numerous. But what is most important, it is undoubtedly the rock the metamor- 
phism of which has produced the serpentine, which is also abundant here. The boul- 
ders of serpentine are first found in great numbers about ten miles north of Kennebago 
lake. They are enormous in size, sometimes 30 or 4o feet in length; and with these 
are boulders of diorite of nearly the same dimensions; but where the ledges appear, 
the diorite evidently passes into serpentine. 

Argillitic Mica Schist with Staurolite. West of the gneiss containing limestone, in 
Phillips, we have a mica schist which, westward in Madrid, becomes quite argillaceous, 
and then again, in the south-west corner of Madrid and in Sandy River Plantation, 
and west as far as Rangeley lake, this rock has more the characteristics of a typical 
mica schist. The strata are everywhere vertical, or nearly so; and often there are 
beautiful crystals of staurolite. One of the finest outcrops with these crystals is ata 
school-house north of Sandy river, three and a half miles west of Madrid village. In the 
river, below the dam at Madrid village, there is a fine-grained, thickly-bedded mica 
schist, which contains concretionary nodules of granite from three inches to a foot in 
length, and from two to eight inches in width. In the larger ones the proportional 
width is much less than in the smaller ones, Five rods below the dam, the fissile ad- 
dalusite schist has essentially the same strike and dip as the compact mica schist above. 
North-west of Madrid village there is a large area of ferruginous schists that probably 
belong to a different series of rocks from those we are considering. In the west part 
of Sandy River Plantation, and in the east part of Rangeley, we have mica schist with 
staurolite. This schist is extensively developed on Saddle-back stream, which flows 
near the Greenvale house. Following up this stream, we find, for nearly half a mile, 
both the schist and the conglomerate; and there is such an intermingling of the two, 
that, unless there have been great changes in the rocks since they were uplifted to 
their present position, they must belong to the same series of rocks. When the stream 
turns and comes more from the east, we leave the conglomerate. Above, a deep gorge 
has been cut in the schist along the strike. On the hill south-east of the Greenvale 
house, where the steep ascent begins, there is a mica schist with staurolite, and the dip 
is S. 20° E. 82°. There is a conglomerate included in this, and unconformable with 
it. On the face of the cliff it was not more than 120 feet in width, but it becomes wider 
as we ascend the hill. It dips N. 30° W. 75°, and stands on the upturned edges of the 
staurolite schist: so it is clear that we have two bands of conglomerate. Just south of 
the inlet of the lake, the schist and conglomerate have the same relations that they do 
on Saddle-back stream. This schist is more extensively developed in this section of 
Maine than any other rock, for, with some of the White Mountain gneisses and schists, 
it occupies the whole country to the north-east as far as Dead river in Flagstaff. 

Rangeley Conglomerate. This conglomerate has given rise to much discussion, on 
account of the flattening and distortion of some of the pebbles of which it is composed, 
but its stratigraphical relations have received very little attention. This conglomerate 
is confined to a limited area, extending N. 30° E. and S. 30° W. from the inlet of 


HEAD WATERS OF THE ANDROSCOGGIN. 363 


Rangeley lake. It is not far from a mile in width, but it becomes narrower northward, 
and in the middle of Dallas Plantation it is only a few rods in width. In the stream 
near the Greenvale house there seems to be, on the weathered surfaces, a marked dif- 
ference between the staurolite schist and the conglomerate ; but, breaking the conglom- 
erate, every portion of it, except where there are actually pebbles, resembles in all re- 
spects the schist: even the staurolite is not wanting. Going across the stratification, 
we find places where there is an abundance of pebbles, and then they are wanting alto- 
gether, or have been so changed that they are not apparent. There are fine outcrops 
of conglomerate three quarters of a mile from Greenwich on the road to Rangeley, and 
at Moxey ledge, near the inlet of the lake. Some of the fragments at the former local- 
ity are a foot in diameter. The conglomerate on its north-west border, both north and 
south of the lake, passes gradually into a rock, which without a lens cannot be distin- 
guished from common gneiss. Looking at this conglomerate now, as a whole, it has 
the appearance of having been formed from fragments derived from a rock which is now 
the argillitic mica schist with staurolite, before great metamorphic changes had taken 
place. The re-formed sediments, which are now the cementing material of the conglom- 
erate, were so little assorted, that in the subsequent changes, in which both the con- 
glomerate and the schist were involved, this material and the schist became essentially 
the same kind of rock. 


PaLeozoic. 


Wrinkled Argillaceous Schist with hard Micaceous Bands. West of the conglom- 
erate there is a broad area of rock, consisting chiefly of wrinkled argillaceous schists 
and a few hard micaceous bands. They are found on the hills south of Rangeley lake, 
and, north of the lake from where the conglomerate ends, it extends nearly to the out- 
let. In the east part of Rangeley it is limited northward near Gulf pond by an intru- 
sive diorite, but, west, it extends about three miles north of Quimby pond. This band 
of rocks has one characteristic in common with some of the paleozoic rocks in New 
Hampshire: the veins of quartz by which it is penetrated, as well as those in the rocks 
immediately adjoining it, have a decidedly fetid odor. There is a band of this schist 
in the hill south-east of Greenvale: so it either extends around the Rangeley conglom- 
erate, or there is here a repetition of the band to the west. The conglomerate men- 
tioned as being found on this hill seems to be associated with this schist, rather than 
with the staurolite schist. 

Lower Helderberg and Oriskany. There is quite a large area in the vicinity of Ken- 
nebago lake that most probably belongs to the Lower Helderberg and Oriskany. From 
their fossils, we are sure that some of the rocks belong to these groups. The area of 
Lower Helderberg and Oriskany in the vicinity of Parlin pond has been known for many 
years, and its limits on the south-west have been pretty clearly defined. The area in 
Flagstaff was pointed out for the first time by me at the Portland meeting of the Asso- 
ciation for the Advancement of Science; and this now adds another to the many areas 
of these rocks already discovered. 


364 APPENDIX TO PARTS I AND II. 


Slates. There is a band of argillaceous rocks that are unlike, in their physical char- 
acteristics, any we have described, which is found on both sides of Kennebago lake. 
The most southern outcrop seen is on Spotted mountain, south of John’s pond; the 
most northern, on Kennebago East mountain. The rock is generally thick-bedded. 
Sometimes it has the appearance of an argillaceous sandstone, and it is sometimes a 
little micaceous; and often the finest and most purely argillaceous bands pass sud- 
denly into a-slate conglomerate. The argillaceous rock on the ridge between John’s 
pond and the south end of Kennebago lake breaks up into fragments more like shale 
than slate. The strike of this rock is N. 40° W. 

Slate Conglomerate. The transition of the slate into conglomerate is so sudden that 
we do not suspect its presence until we see the boulders or ledges where the change 
occurs. Boulders of slate conglomerate are abundant on the southern shores of Ken- 
nebago lake, and outcrop in the vicinity of Flatiron pond. 

Calcareous Sandstone with Fossils. Several years ago Mr. H. P. Dill found boulders 
of fossiliferous rocks along the river in Phillips; hence it has long been known that 
fossiliferous bands existed somewhere in this section. The rock seen in the vicinity of 
Kennebago lake is not the same as the boulders of Phillips, though further exploration 
may show that they are found here; but it seems more probable that the ledges from 
whence the Phillips boulders are derived are in some other locality, since the Phillips 
boulders are a pure sandstone, with fossils of Lower Helderberg types, while here the 
rock is a calcareous sandstone, with some fossils that are found with the Oriskany in 
the vicinity of Parlin pond. The change, however, does not appear to be any greater 
than it is between Parlin pond and Moose river. It has long been known that the line 
of demarcation between the Lower Helderberg and Oriskany in Maine is not so well 
defined as it is in New York. At Kennebago lake the number of species is quite lim- 
ited, and they can scarcely be distinguished except upon the weathered edges of the 
rocks where some of them are well brought out. 

The fossiliferous rocks here are probably limited to the area north of Spotted moun- 
tain between Flatiron pond and the bridle-path. 

Glacial Drift. The study of drift in a region entirely covered by forests is more dif- 
ficult, even, than the study of the ledges. In the vicinity of Rangeley lake, however, 
where there are farms, the absence of stratified drift is generally very noticeable. The 
most common boulders in the country about the east end of Rangeley lake are diorite ; 
and these are derived chiefly from the numerous dykes in the west part of the town of 
Rangeley. There are very few boulders except of diorite on the bridle-path to Kenne- 
bago until we get within three miles of the lake, when we have those of slate conglom- 
erate, calcareous sandstone, fossiliferous, and a few granite boulders. 

About ten miles north of Kennebago lake, particularly on the west side of the river, 
we find a remarkable collection of boulders. They consist of sandstone schist, serpen- 
tine, and chlorite, with a few granite boulders; but as we go northward, the granite 
boulders increase, and soon they begin to predominate, and the others disappear alto- 
gether. Some of these boulders are of enormous size, and are probably derived from 


HEAD WATERS OF THE ANDROSCOGGIN. 365 


ledges in their immediate vicinity. There is another great collection of boulders on 
the Cupsuptic river below the gorge already referred to; and these are derived from 
the granite ridges on either side of the stream,—for, soon after we pass the granite 
ridges, these boulders disappear. Elsewhere no great collections of boulders were ob- 
served. 

The drift striz on Bald mountain, between Moosetocmaguntic and Rangeley lakes, 
are S. 55° E.; near Rangeley, on the south side and near the inlet, S. 35° E.; and on 
the high land south-east of Dodge pond, S. 65° E. The stria here are in the direction 
of Saddle-back mountain. 

Modified Drift, Kames, etc. A few gravel ridges in the west part of Dallas Planta- 
tion were the only gravel deposits resembling kames that were seen in the vicinity of 
Rangeley lake. On the lower part of the Kennebago river there are some well marked 
kames; and their absence was also noted on the river till we get about ten miles north 
of Kennebago lake, where there are some well marked ridges, but these do not extend 
more than two miles. On Cupsuptic river there is an almost entire absence of kames, 
as in the other regions we traversed; but on the lower part of the Cupsuptic, for six or 
eight miles, there are sand and gravel plains extending some distance from the river. 
These sand plains are characteristic, also, of the Magalloway; but, so far as our ob- 
servation goes, they are wanting on the Kennebago. 


Eruptive Rocks. 


Granite. On the north-west branch of the Kennebago river, near its source, there 
is a band of granite probably two miles wide. It is a typical variety, consisting of 
quartz, feldspar, and mica in more nearly equal proportions than we often find them. 


Fig. 64.—BaLpD MOUNTAIN. 


a, the lake; 4, schist on the border of the lake; c, granite; ¢, granite,—a narrow band near the top of the 
mountain; e, schist on the summit of the mountain. 
There are, however, two kinds of feldspar, the triclinic being more abundant than it 
is commonly found in the coarser varieties of the New England granites. On the 
Cupsuptic river, in No. 4, R. 4, we find a similar kind of granite, which extends north 
and south nearly through the entire range. South-west, in No. 5, R.1 and 2, there 
VOL. Ill. 47 


366 APPENDIX TO PARTS I AND II, 


are large areas of granite; but its greatest development we find on Observatory and 
Aziscohos mountains, and there is quite an extensive outcrop in No. 4, R. 1, on the 
south-west side of a hill north-west of the upper dam. The top of Bald mountain, 
between Rangeley and Moosetocmaguntic lakes, except its very summit, is composed 
of this same coarse granite. The way in which the schist is caught shows better the 
intrusive character of the Conway granite than any other example we have seen. 
Fig: 64 shows clearly this feature. To the left, on the border of the lake, we have 
the schist with an easterly dip; and as we ascend the mountain the granite suddenly 
appears, and extends almost to the very summit, which is crowned with the same 
kind of schist as that at the base; but in it is a well defined band of granite, about 
six feet wide, cutting it so sharply that the dip, which is westerly, is essentially the 
same as that of the mass on either side. South-east of Moosetocmaguntic lake, in 
township D on the head waters of Swift river, there is a band of granite, but it is a 
finer variety than those found northward. 

Diorite. ‘The most extensive outcrop of intrusive diorite found in New England has 
its southern limit near Gull pond, and outcrops are found for more than four miles to 
the north. South-east of Kennebago lake it forms a sharp mountain ridge, which rises 
more than 600 feet above the lake. The rock is generally a mica diorite, and it often 
contains garnets. On the southern limit of this diorite are fragments of schist; and it 
probably also penetrates the Paleozoic strata in the vicinity of Kennebago lake. There 
are many dykes of diorite in Rangeley immediately north of the lake, and the rock re- 
sembles the great outcrop northward, except that there is more hornblende and fewer 
garnets. 

Felsite. The summit of the diorite ridge south-east of Kennebago lake is chiefly a 
compact feldspar ; and one variety contains a few garnets and alittle mica. This forms 
great cliffs near the summit of the ridge. 


APPENDIX G, 


THE ATLANTIC SYSTEM OF MOUNTAINS. 


Want of time will prevent us from preparing a chapter upon the elevation of moun- 
tains and the occurrence of earthquakes, as promised in the preface to Volume I. In 
its stead, I will describe in greater detail the suggestion made upon page 6, Volume II, 
in regard to the distinctive features of the Atlantic system of mountains. I hardly 
need say there is a world-wide difference between the views of the age of mountains 
expressed in these reports, and those entertained by the metamorphic school of geolo- 
gists. For this reason, it is important to set forth the correct history of the whole 


THE ATLANTIC SYSTEM OF MOUNTAINS. 367 


Atlantic range, in the hope that the public will see that the name Appalachian ought 
never to be applied to any of the New Hampshire mountains. 

The Atlantic system of mountains includes the high lands bordering the Atlantic 
ocean between Newfoundland and Alabama, bounded westerly by a depression readily 
traceable from the St. Lawrence and Hudson valleys to East Tennessee and northern 
Alabama. It may naturally be divided into three sections,—northern, middle, and 
southern, each entirely encircled by low land, if not the level of the sea. 

The northern section is confined to Newfoundland, entirely surrounded by water. 
The culminating point is about 2,000 feet. The Nova Scotia elevation may be regarded 
as a branch. 

The middle section, with a Green Mountain branch, is nearly encircled by tide-water, 
having the St. Lawrence gulf and river opposite a great portion, thence following the 
Champlain depression to the Hudson, the highest divide being 150 feet above the sea. 
From Albany to New York, and thence around to the starting-point, it is all tide-water. 
The culminating point is Mt. Washington, 6,293 feet. 

The southern section is the longest and highest, reaching 6,700 feet in western North 
Carolina. The eastern boundary is washed by the sea; and the western is the great 
valley between the Hudson and Alabama. 

The course of the Great Appalachian valley may be traced minutely thus: From the 
St. Lawrence to Lake Champlain is a rise of 90 feet. Sixty feet more brings us to the 
highest point in the depression between Lake Champlain and the Hudson river. The 
valley leaves the Hudson west of the Highlands, strikes across through northern New 
Jersey to the Kittatinny in Pennsylvania, 10 to 18 miles wide, and from 200 to 600 
feet high. There is then a descent to the Potomac, and an elevation to the head of 
the Shenandoah. Continuing southerly, this valley rises to 2,595 feet at the highest 
part, near the sources of the Holston river. Following the great valley of Virginia, the 
altitude is 2,741 feet near the south line of the state, 898 at Knoxville, and 675 feet at 
Chattanooga. The highest part of this valley in Virginia does not correspond in lati- 
tude with the culmination of the mountains, as that point is reached in western North 
Carolina. This valley is regarded as the western boundary of the Atlantic system, and 
the eastern limit of the Appalachian ranges. 

A section from East Virginia to Cincinnati crosses five different types of orographic 
structure. First, is the Atlantic plain, nearly 150 miles wide. No mountains exist in 
it. The elevations are those made by streams cutting into the Cretaceous and Tertiary 
horizontal deposits, which when protracted display crenulated edges. Second, are the 
elevations of the Atlantic system known as the Blue Ridge, with obtusely pointed sum- 
mits. Third, is the valley of the Shenandoah. Fourth, are the long, narrow Appala- 
chian ridges or the Alleghany Mountains. Fifth, is the elevated plateau, called collec- 
tively the Cumberland-Alleghany-Catskill plateau, with a quaquaversal arborescent 
drainage. The Hudson river, with its Mohawk tributary and the Susquehanna river, 
cut across all these five types of orographic structure. 

Most authors call the Atlantic and Appalachian systems by this latter name only. I 


368 APPENDIX TO PARTS I AND II. 


shall endeavor to show, from a study of their contours, their geological structure and 
composition, their separation by a great valley, and their identity with the Alps and 
Jura of Europe, that they are sufficiently diverse to be known by different names. 

Distinctive Atlantic Features. These mountains occur as short, sharp ridges par- 
allel to one another in echelon arrangement. Their summit lines are irregular, and 
their peaks obtusely pointed. The culminating points are higher than those of their 
neighbors, reaching 6,300 in the middle and 6,700 feet in the southern sections. The 
rocks are ancient gneiss of Eozoic age, Laurentian, Montalban, and Huronian, with 
commonly inverted dips. The periods of elevation were mostly pre-Silurian. On the 
west side of the Green Mountains of Vermont and the Blue Ridge in Virginia, a portion 
of the earth-masses included with other systems consists of Silurian sediments standing 
at high angles. These are so involved with the gneiss as to indicate an elevation in 
Middle Silurian times. 

Distinctive Appalachian Features. Contrasting with the Atlantic elevations, the 
Appalachian ones occur in interminably long and narrow ridges, having level summits 
curving in the form of loops in the north, and terminating in pairs of straight ridges 
cut off short by faults in the south. Occasional gaps in them allow of the passage of 
roads. The elevation is usually 1,000 feet. The variation is from 800 to 2,500 feet; 
and in the Peaks of Otter in Virginia 4,000 feet is reached, in the neighborhood of the 
greatest elevation of the boundary valley. The rocks are altogether sedimentary, con- 
sisting of sandstones, shales, and a few limestones. They are curved, making the 
normal and symmetrical folds like a series of ocean waves. None of the dips are in- 
verted. They are Paleozoic exclusively ; and pebbles of the sandstone have often been 
derived from the breaking down of the crystalline schists of the Atlantic rocks to the 
east. The period of the elevation was at the close of Carboniferous time. 

Connected with this is the great plateau, commencing in Alabama and Tennessee, or 
the Cumberland tableland, with a mean elevation of 2,000 feet, and a width of 30 to 40 
miles. This is 3,000 feet high in Pennsylvania. It occupies a considerable breadth in 
central and southern New York, 2,000-2,600 feet high, and, highest of all in the Cats- 
kills, 3,800 feet. Here it terminates. It differs from the Appalachian mountains only 
in the smallness of the foldings, since in the coal plateau of Pennsylvania six basins, 
with the anticlinal arches between them, are described, and the same axes are pro- 
longed northwardly into New York. 

The Appalachians are divided along the Kenawha river in Virginia by a north-west- 
south-east fault, coinciding nearly with the highest part of the great valley. The Ke- 
nawha is the only one of the rivers flowing into the Mississippi valley that reaches and 
crosses the great valley. This break was produced bya great strain upon the crust, 
evidenced in the fall of the land northerly. It will be noted that the Atlantic moun- 
tains start with the culmination in North Carolina, and in northern Virginia divide, the 
one branch becoming the South Mountains in Pennsylvania, and the other sinks to the 
sea-level near Philadelphia. The low mountains of Staten Island indicate its place near 
New York. They rise into the White Mountains of New Hampshire beyond New York. 


THE ATLANTIC SYSTEM OF MOUNTAINS. 369 


Then there was a sag along Hudson river, which may indicate the course of another 
break at the lowest part of the mountains just as the other fault shows itself along the 
Kanawha where the ge-anticlinal ridge is manifest. 

Concerning the great valley, Lesley remarks that there is ‘‘an unbroken rim of Que- 
bec and Laurentian from Georgia to the extreme eastern end of Canada, contrasted 
strongly with the plateau of the coal, commencing in Alabama and cut off square by 
the Hudson, the open valley of the Lower Silurians everywhere keeping the two systems 
apart.” 

In Europe, physical geographers refer the Alps and Jura mountains to different sys- 
tems, characterized by features similar to those just indicated between the two portions 
of eastern America. The Alps correspond to the Atlantic, the Jura to the Appalachian, 
and the valley of Switzerland, prolonged into Bavaria and Moravia, to the great Appa- 
lachian valley. A section from Italy to the Rhine valley would be very much like the 
one in our country from eastern Virginia across to Cincinnati. 

The Alps are composed of crystalline rocks centrally, with Carboniferous, Mesozoic, 
and Cenozoic groups corresponding to each other upon both sides. The structure is 
fan-shaped, but explained by supposing it to have been an anticlinal arch like a loop 
overhead, long since broken down and removed by denudation. The newer groups are 
arranged in close synclinal troughs, the older nearest the central crystallines, and con 
sequently sometimes resting upon the newer ones by a species of inversion. The rocks 
of the Jura are largely Mesozoic, and are the best known exhibitions of the particular 
belts called for that reason the Jurassic. The Alps and Jura of America are there- 
fore very much like their prototypes in Europe, in all essential particulars. 

Authors have variously compared the American with the Swiss mountains. Guyot* 
says that the western portion is like the Jura,—adding that ‘there is one feature which 
distinguishes it [the Appalachian] from the Jura: it is the well-marked division into 
two longitudinal zones of elevation,” or the ones distinguished above as Atlantic and 
Appalachian. The same author includes the Adirondack mountains with the Appa- 
lachians. J. D. Whitney+ speaks of the Cordilleras (Pacific highlands) as like the Alps, 
and the Appalachian (Atlantic highlands leaving out Adirondacks) as like the Jura. 
The attempts of these distinguished authors to correlate our mountains with the Alps 
and the Jura, strengthens our conviction of the propriety of using special names for 
-the chains corresponding to them so perfectly as do the two divisions mentioned south 
of the St. Lawrence. 

That the name Appalachian is commonly used to include both these systems, is 
undeniable. My suggestion is, that we adopt an improved terminology, at least in 
geological treatises. Two or three considerations may be noted. 1. The desire for 
a single name to express the mountains along the eastern slope of the continent has 
led to the undue extension of the name Appalachian. But it should be remembered 
that, if it is used appropriately, it must include the Adirondacks and Labrador moun- 


* Amer. Your. Science, ii, xxxi, p. 166. tT Walker's Physical Atlas. 
VOL. Ill. 48 


370 APPENDIX TO PARTS I AND II. 


tains also, for in the study of geography we are not to be confined to the limits of the 
United States. So far as appropriateness is concerned, we may as well include the Lab- 
rador as the White Mountains under the name Appalachian,—in fact, we must. Guyot, 
in his Physical Geography (1873), has perceived this difficulty in terms, and uses the 
name Atlantic highlands to include all the elevated region adjoining the eastern coast, 
and places the Adirondacks with the Appalachians, calling attention to the plain east 
of them. Harper's School Geography follows Guyot in using the terms Atlantic and Pa- 
cific highlands for the mountainous regions on the two sides of the continent. 2. The 
merging of these two systems under one name has been facilitated also by false theo- 
retical notions. The advocates of the metamorphism of New England rocks legiti- 
mately assume the Atlantic to be of the same age with the Appalachians. If their 
doctrines were correct, this conclusion would follow. 3. The suggestion of the use of 
the term Atlantic for the eastern portion of this mountainous district is intended to be 
for geologists, not geographers. The eastern border will then have its Laurentian, 
Atlantic, and Appalachian systems of mountains formed in three separate sets of peri- 
ods, the Eozoic, early and late Paleozoic. There will be further sub-divisions of these 
three systems developed as the subject is further studied. 


History oF THE ATLANTIC MouNTAIN SYSTEM. 


The place of this system of elevation will be further appreciated after a brief sketch 
of the several important features of the physical history of the belt of land east of the 
Appalachian valley from Newfoundland to Alabama. 

1. The original sediments of this area, now converted into rocks, were deposited in 
a basin of Laurentian rocks, the Adirondacks on the west, and near the coast an 
eastern line of similar age. The breadth of the eastern rim was greater at the south 
than in the north. 

2. Precisely how far our porphyritic gneiss, Bethlehem and Lake Winnipiseogee 
groups are coeval with the Laurentian, is not certain; but it is clear that the Montalban 
rocks followed them, and that the first epoch of elevation occurred after their deposi- 
tion. The first decided evidence of disturbance is afforded by the Franconia breccia. 

3. The whole Huronian period next intervened. New Hampshire does not afford 
any evidence of elevation where the Montalban and Huronian rocks meet. The next 
upheavals were in connection with the disturbances accompanying the formation and 
intrusion of the Pemigewasset granites of Conway, Albany, and Chocorua, and the 
porphyry. This was evidently the epoch of greatest disturbance known in the White 
Mountains. It is to be compared with the elevation of the Green Mountains, where 
the Cambro-silurian formations have been folded and faulted. 

4. There seems to have been, next, a submergence giving rise to the Gulf of St. Law- 
rence and to the Appalachian valley, unless this movement was connected with the 
Green Mountain elevation. 

5. There was also a time of depression all over northern New England, to allow of 
the accumulation of Helderberg limestones. This was followed by,— 


. THE ATLANTIC SYSTEM OF MOUNTAINS. 371 


6. The last important elevation known in the White Mountains. The forces caused 
the Helderberg strata to be put into vertical and inverted positions. We have no evi- 
dence illustrative of the Appalachian revolution in the Atlantic district, unless it may 
possibly be represented by the smaller curvatures in the andalusite slates along the 
Mt. Washington carriage-road. Horizontal Devonian sandstones, resting upon inclined 
Helderberg strata along the eastern edge of the Atlantic district in Maine, fully con- 
firm us in the belief that the Appalachian revolution, at the close of the Carboniferous 
period, was principally confined to the formations west of the great valley. 

7. The changes in Mesozoic and Cenozoic times have diminished the size of the 
Atlantic mountains, so that they are scarcely recognizable between Connecticut and 
Virginia. The deposition of the Triassic sandstones would seem to have required a 
depression below the present level. Although no marine fossils occur in them, we 
-must believe the basins to have had oceanic connections. 

8. There must have been an elevation following the Triassic period sufficiently great 
to furnish the barriers for the Lower Cretaceous lake extending from eastern Long 
‘Island through New Jersey and a part of Pennsylvania. The former extension of the 
Hudson river channel 80 miles out to sea may have had some connection with the exit 
of the water from this Cretaceous lake. 

g. A later depression is indicated by the presence of shallow water, Ico miles or so 
in width, between New Jersey and the Great Banks of Newfoundland. (See Pl. I, 
Vol. II.) 

to. There must be added the changes of level described in the glacial and Champlain 
periods. Authors are not agreed as to their extent, while the current of opinion and the 
progress of discovery constantly tend to diminish their magnitude. 

This review of the history of the Atlantic chain enables us to realize its magnitude, 


although the northern and middle sections are now partially submerged beneath the 
ocean. 


APPENDIA. HH. 


THE GEOLOGICAL MAP. 


Not until the last moment has the geological map in the six atlas-sheets been com- 
pleted. There are some small changes upon it from the statements of the text of Vol- 
ume II, which are in all cases improvements. The north-west sheet shows for. Quebec 
the elaborate subdivisions of the Huronian (Quebec), delineated by Sir. W. E. Logan, 
not yet published in the report of the Canadian geological survey, and kindly furnished 
us by A. R. C. Selwyn, the present director. From some familiarity with the country 
south, I have endeavored to carry the same classification into Vermont. I must except 


372 APPENDIX TO PARTS I AND Il, 


the Green Mountain gneiss, which Logan considered to be a metamorphic variety of 
the Sillery formation, overlying the Lauzon. As shown in my sections in the Vermont 
geological report (1861), this group everywhere underlies the Huronian, and is there- 
fore older. With this exception, I find no fault with Logan’s representation of the for- 
mations, but differ from him in placing the Lauzon below instead of above the Levis. 
Had I occasion to map the ground de novo, I should probably not use any of these 
terms. The limits of these groups have been stated upon page 463, Volume II. 

I have elsewhere pointed out the anticlinal structure of the Green Mountains. This 
fact authorizes the deduction that the formations upon both its flanks are of more mod- 
ern age, and that the Green Mountain gneiss is essentially Montalban, and underneath 
the Huronian. Essex county, Vt., is represented very differently from the delineations 
of the state geological map. 

The additions to the Maine part of our sheets are entirely original contributions from 
our survey. Want of space prevents a description of the details south from the Andros- 
coggin lakes. 

I regret much not to have had sufficient time to incorporate all the observations of 
the position of strata throughout the state upon the map by appropriate symbols. The 
necessity of having every part of the work completed by a specified date has not given 
us sufficient time to perform this task. The conclusions to be derived from such delin- 
eations have been approximately presented in Pl. XXVI, Volume II. 

The maps were executed by Julius Bien, of New York, and are not surpassed, for 
excellence of finish in the coloring or engraving, by any similar work heretofore issued 
in the United States. 


APPENDIX Lf. 


PANORAMIC VIEWS. 


- Allusion has been made in Volume I to a number of panoramic views taken from 
several of the White Mountain summits, by G. F. Morse, of Portland, Me. Owing toa 
change in the size of the Atlas, it was found necessary to re-draw these hand sketches, 
and they are all sketched upon two of the large sheets. Upon the first appear pano- 
ramas from Mt. Washington and Tremont, covering the entire horizon, divided into two 
parts by the points of compass. The upper begins at the west, and terminates at the 
east, the eye looking northerly. The lower view commences where the first leaves off, 
the eye being directed southerly. The same remarks apply to the panoramic views 
from Mts. Carrigain and Chocorua upon the second sheet. Both sheets also contain 
several other profile views, covering only a small part of the circuit, being designed to 
present the aspect of important or interesting ranges. 

Another sheet has been prepared in a different style, by J. Rayner Edmands, with 


DESCRIPTION OF A CAMERA USED IN SKETCHING, 373 


the help of a camera. This is like a photograph, reproducing nature exactly. A com- 
parison of the two styles of profiles will suggest many interesting remarks. 

The view from Monadnock is inserted by request, as it completely verifies the cor- 
rectness of the scout Willard’s report in 1725. He ‘‘saw Pigwackett lying one point 
from sd mountain and Cusagee mountain and Winnipesockey laying north East of sd 
Wannadnock.” The mountains now called Pequawket, Kearsarge, and Gunstock may 
be seen in precisely the positions given by Willard. This fact indicates the correctness 
of the common application of the names Pequawket and Kearsarge. Within the past 
two years the people of North Conway and Bartlett are beginning to write the name of 
their mountain Kearsarge instead of Kiarsarge. 


APPENDIX J. 


DESCRIPTION OF A SHEET OF PROFILES TAKEN WITH A TOPOGRAPHICAL 
CAMERA. 


By J. Rayner Epmanps. 


The topographical camera is a portable instrument, a modification of the old camera 
obscura, by the aid of which one may draw the forms of objects as seen from the point 
occupied, covering a large horizontal angle without distortion or variation of scale. A 
description of it will be found in Appalachia, Volume I, page 169. 

In the summer of 1876, the writer, with the first instrument of the kind, visited several 
White Mountain summits, to test its performance, hardly expecting at first to obtain 
material of permanent value. When, therefore, the results proved worthy of publica- 
tion, it became a matter of regret that they were so fragmentary in their nature; for no 
view had been drawn throughout the whole circle, and vacant foregrounds or hazy back- 
grounds rendered much of the work unavailable. During the following summer a few 
additional drawings were made; but, owing to unforeseen circumstances, the omissions 
of the year before were not generally supplied. It is also to be regretted that copies 
of the camera drawings have not been carried, for revision, to the points at which they 
were made. In presenting the profiles shown upon the accompanying plate in the Atlas, 
the writer is conscious that much remains undone which would materially improve their 
appearance, since he has rigidly adhered to the rule of showing nothing which does 
not appear on the original drawings, except that a few conspicuous omissions are sup- 
plied in dotted lines. 

The accuracy with which the relative positions of objects can be drawn has been 
established by measurements upon independent profiles of the same subject, and also 
by comparison with the readings of a telescopic instrument. In some cases, haze or 
insufficient illumination may have caused the omission of lines or parts of lines; in 
some cases, subordinate lines may have been given undue prominence in making or 
copying the drawing; but in general the forms may be relied upon in considerable 


374 APPENDIX TO PARTS I AND II, 


detail. No satisfactory means was originally devised, as a part of the instrument, for 
accurately locating the horizon upon the paper; but fortunately several of the points, 
at which the fullest or most interesting profiles were drawn, were also occupied by Prof. 
E. C. Pickering with the micrometer level, thus supplying the missing data without re- 
sort to extended calculations. 

With the exception of that from Monadnock, the profiles are published on a scale of 
about five millimeters to the degree; but the scale attached to each is intended to com- 
pensate for unavoidable variations. To measure horizontal angles with the greatest 
attainable accuracy, use an ordinary metric scale; but in addition to the desired angle, 
measure with it the angular distance upon the attached scale between two graduations 
nearly under the two points. The difference between the nominal angular distance on 
the attached scale and its measured angular distance, as given by the scale used, should 
be applied, with the proper sign, as a correction to the angle measured upon the profile. 
Horizontal angles may be conveniently measured to tenths of a degree. For readiness 
of identification, thé zero of the attached scale is made to coincide as nearly as may be 
with the south, so that its readings shall give directly the geodetic azimuth. The pro- 
file from Monadnock is on a scale of about one centimeter to the degree, or twice that 
of the others; but for the part of the view to the right of Belknap, the data are want- 
ing for giving the precise scale. Also, the position of the horizon is not so well known 
for the second lines of profile from Monadnock and Starr King, as for the others. On 
the other hand, the distant view from Monadnock, extending between the Franconia and 
Ossipee ranges, has received more careful treatment than anything else upon the sheet. 

Any identified point not on the sky-line may be found on the profile by means of its 
vertical position, given before the name. For this purpose, mark off from the zero of 
a short paper scale the distance between the horizon and the bottom of the profile, this 
distance being shown at either end of the sheet. Then, if this mark be placed any- 
where upon the bottom line (the scale running in the direction of verticals), the zero 
will indicate the level of the occupied point; and the vertical position of the point 
sought may be read directly upon the scale. 

For indicating minor points, and also those whose names are ambiguous or little 
known, it has been found expedient to use the notation adopted by the Appalachian 
Mountain Club, and described in Appalachia, Volume I, page 7. This consists of a 
capital letter followed by two numbers. The capital letter indicates one of twenty-six 
sections into which the state of New Hampshire has been divided; the number before 
the period indicates a certain mountain in the section; and the figure after the period 
indicates a special summit of the mountain, as indicated upon the maps of the club,— 
that is, different summits of the same mountain differ only in the last figure of the 
designation. 

Distances, when given, are expressed in kilometres, the number being enclosed in 
brackets. One kilometre is a trifle less than five eighths of a mile. 

Conspicuous unidentified points are arbitrarily lettered, for convenience in defining 
future identifications. 


375 


PRELIMINARY RESULTS OF TRIANGULATION. 


ro60€ zo €S 
, $h66z S*go x1S€ $S'2S PS IL €€-2S ge fb Pee eee nance ween enn eneener esas een aeeee sees CUB AIDICD 
gzEgt Erov rE 
66zr€ gtzz obz gf'1r €x zl goes gz ep renee tenes ee ene er ee eeeeeecsnsoesereseees see ODAOID 
bgSolb of LS bof 
S-oogeg €r 6€ € w6zr gt 2 66:zr gr ty sesceees suoyZulyseAA “TA 
6- abr £:6z oF ggz sasmoy ureUNOWW, YI4ON 
9° £6 Lge g€ ozz gzob So 1Z £6'6r go +P aSuesivay Mou “(€S -1Sg1—ejodno ‘asnoy 3omenbag) 
€Sz6€ jz gs bz 
S-6€6Sz i go ssé obLo go aL Lz LE Go €% SSR WEG eG seas ** pleppois 
€-€zzSz go Sz ggz 
L-€Sohr S€ er €& 6g'Ze iS rh Eb'gS zz EP “ureqUNOY] YINOG eZivsivay ou (aBies1e2y) 
L+6go9h €€ fr + 
L¥g6x €€ oS gz r6gh z& x L6:Lb Ez €b ace ceca secede (1101 | 
g'fbrbz bE zr 96 
z6gzle onuooursuy), gr gh z z6'6r FE rh fo'rb Ex fb aids SieHRENOT GS RISE ISSIR ERNE AieEy eens SNES OS OA BOSONS 
z-olsle “yooupeuoyy oz er Sz be i 
S*6LbLE onuoouesuy) gz gr zbr to S€ z2€ fo-bo 2S xh 6z'vo Sr fh i giSicin diosa: rain! w dTGiaieie oisiaiens.sieisiazs)sisisie aisieisteigielnereie seg re Moy 
E-rbbbs “yooupeuoyy zo gz fz gf SE 1S 
Czbeca **onuoouesul) 1 ar b6 os Fore] tle o£ 9% zs 7A LS*2S 6¢ oP Sih einin eta dialed aie’ ainieit Cereal e aiiena!eis.8se:9ieia-aeieieisie SST IIOIZ) 
grobolz “yooupeuo py £€ Sz g6z g& LE gir : 
g* bgbre £o gt ce $s gz Srz €S°Sb gh 5dA 1z"go Sh oz eveneeensceeenens cece nerteececess (VOTIVE IO) UOSEIAL 
o S*16L6b broS Eo Lge Se Le Lor 
L+06692 S*g€ ox ore g'1S 6r gor €z'6b gf of ze-fr 6S ab Leb eee eeweneener esse seeeeenteeees ess STBOUS JO SO]ST 
zr Esese brE gt bbz LSE +E t9 
g'acgeh groo of +2 Stor Sx Sz gStoS 12 OxZ rzszxt Lo € eee eee . ACMEYOTIMET 
LghShy ofr 62 zl vgs Lo 22 
9° 9ghh6 E‘oz fb 6€ 6'So fr 61z 6r-0€ go zh 19'6E 1S 2b *yooupeuoyy 
1°z6619 6°61 bh or 6°61 SE o6r 
9° 99942 g'gS zr of gtEr gf bbz Egegr SE xZ bogs gS cb peenereeeeeeeee sees onuoouBouy) 
z*zo06Eg s+ ses snoquauesy | 9'6b oo 27 girS z€ oof 
S+rgg1 : ‘queseatg “IT | E'Ex go gf grok Eb Liz oLtor zz iL g6'zo rf fb oa ASSESS TG Ee GIRO eee te? aS OISUNS) 
S*zLg6g "queses[g ‘JJ | S'60 br ESE ree 6r E€Lr ggreé rb of grsez €xr fb sha ttorropy fsnopuauesy 
ane ee eet ae eneees Strasse eeeeetee|eeseeeeeceersssreeselacseesesensesesssees| Q6'0Z 6h OL €S°SE 10 +h wee “oy “Gueseeyd “3 
“ so “ut 8 “ #0 “ a) 
*si9}9W—I9UeISI, ‘NOILVLIS OL |HLIOAWIZV MOVva “HLOWIZV “ACNLIONOT “EQ NLILVT “NOILVLS dO ANVN 


‘wonendwos Yayo B jo JURM OJ ‘paystumny oq JUasedd ye JOUULD sjoa{qo AreNNI19} JO JoquInuU o81Y] v JO suOTIsOd oY L 


“yuasaid ye opeut 


aq ued uoleyndwoo yeuy ou ‘aouanbasuoo ur ‘pue ‘ajaduooUT st YOM Pley oy) yey} UOSeaI oY} J0y ‘Areururpesd AyessoooU ase s}Nser aL 


‘AHAUNS ISVOD "S ‘() HHL AO INSANZINIURANG ‘NOSUBILVG ‘q “D ‘LdvD Ad CHHSINYAT 


‘9 -1481—SaIHSAWVH MAN dO ALVIS AHL dO NOILVINONVINL AUVILYAL GNV AUVANOOUS AO SLTINSAY AMVNIWITHad 


“HM XIGQNUddV 


APPENDIX TO PARTS I AND II. 


376 


gforr ein **yoadsorg begh Lgz S*go gor 
6g1ZE se * 2DBzIIIY AA zgz €2& gZE fbr S+zS Lo 1L ris 6€ €F “Ty ysery, 
obotz oe “axBusayE Y Ligh gSz roo" LL 5 
6Szor eR pror giz bzz of sp fdr xf zZof or fF “yunourezeZ 
éeces gar ite gr 26 L € 
‘1S ile ‘6r zi ‘or gi 1 S*€x ox b+ +++ Ayovayoiy—uojsur 5 

prgre 3-45 goz 20 6z e : ? SEE I 
S1zgb €+x1 6bz FE 69 g6s Sz iL Sho gz bb sees se teeeee “Sury ueig 
glg6b g rE Sr zbe gfe ‘ 
ogoze E-gh 16x g:rS oz gf €S x2 ger ve tr cto agung 
€LSgz bbr Sor 1°00 =Sgz 
zolgb I'rIr ob girs 612 fo ze aL t'60 29 €F ren eeeeee teeeeemoy{o9 
rrb6z zo zl g'goh 182 
zhotr 6°€S Shr €-1b See Gf 6r 2l Iz tL $b . Stree ereeesrrepy 
1612 6*zS 411 L-Lr 162 r 
6£256 €°6€ gfx Zgo giz 6°SS gh zl Phe 1 bb teens Snr eres 
gllzh zfo £6 rSz cle PIPUSUETAL 
beh begs Gee €9£ Soz atte Bh “60. 6x tb sy Haat iabagyevaecnreny oda ance pieoeeee 
oes 60h of Loo Sz 2 HS PED 
SoLLL LSS 604 L-Lr gz €-er 9S zl Lex Lo +b HS Se near renee Slat ate sae ee re ae ony 
6bExL 4 *saqnd zroz $9 zeLp fhe - 
gbos ve + uopsory r'SS Sor Erof Sez bebr 6h al €+or gf ep aicieiiie Sasori neta sahil Bar Tae 
zSLor Bo *ueSipses g°gr Zr Leer L61 ali 
z6Lor am reyes 6z gor IZ 9gz LoS £0 aL eos Lr & SAGAS AGS RSET Hb Oe UR eINLeRITT RRR So Sadteung: 
boobr a ‘aSpay preg Ebo Fhe €€x +9 
gbrge oe gle ggr Sof g S‘rb Sb xL g°Sh iz $b Sisson ISA Sai AN SiRR Sinai eiieisieai her Oe Se oOME- OE 
6r00€ g°fo gba S°Lxr gir 
L6€xz bbz bez z2ze bP Eo'rh gf 12 EgZE 60 tb HERG SERS S SAO MRee Br Ae Sa eaten te aides eho oa gS KepaeT 
61rbz zLr bz 6°Sz bb , 

6SSE €'g0 9gz bz gor Cri ve pea 1z'0o0 iS ty SSisieMbi ion piece cebedayhiststacsinininntssane: Seteiaidiateiertrarsiaisieteiets Soper aay 
ee axneyIsoopy Iv gSr Se gc 3 JOU A 
oobby reese saqns, +S bg 9S + LEEE gS 3Z zr‘Zx Lx +b rice RGR IGT eTaal MESSRS: a8 aetna e ah aR pape 
obozr “yy Aroveasrasq¢Q, 6:Sz Sz 6rE $2 
ogzSh vere soSresivay €-6€ 6br Sle 62€ gS'6z go aL 16:20 +h Eb " Se Shiaaieattabs SIRE Salen alveertanerene seg ee 
zzlor sree Try AToyeasasqQ, who ofr S*10 of€ 
SSE wee ve+e* saopsol S*rb zor 1°9€ ape zi:Lo iz 2L LS 6x Lb &b eee ee eee ee er sccnhgyity 
r6L1€ ty AroyeasosqO gilo Sz 6°00 Soz i 
Szz6r + **uopfoid grr gl Z'zo -gSs gf*go Le aL ge-sh oz fb ae SESS, +++ aunosy 
6Sozb gi'fo 6gr zlo 6 

€1L1z 6'60 Sze 6:41 Sb L6-bS 6h xL gores 10 +b * ‘ayNeLISOOPT 
zSo6z zZo— gb b6r gzz 5 

6ESz gs Lor ess Lbe Sg-Lo Lr 2Z wS'gr 2b EP ecsieis) **(aZa]]oo ynowjseq AveU) [[Iy A107 eAIVS 
seer €:So or begh 6gz i oe Pee a @ HOS a0 
zgSLbr 6r 661 rile 61 Eb-ge 10 2b 6S:Lo €S Eb ‘ REINS Se US See SGT ED 
Sich + [Ty ueeg £€€ clr Gro 2SE 

Egogr presses ee esgSiesreayy $:#S fos $'bo tz gS9S gf 1 sberh gb fh sases sie Sa ialeneiih letatel a acaneietaitin ees Mane ania eo ue 

“i as) “ so “ so ji dG 
*S19}9UI—SIUeISIT ‘NOILVIS OL |'HIOWIZV MOVvd “HLOWIZV “ACOLIONOT “ACNLILVT “NOILVLS 40 FNVN 


‘panutzuoI—uorjzujnsuviay fo Sqynsay havuruiaatg 


INDEX TO PART IL, 


Page. 

Acadian fauna, . 282 
Accumulation of ice-sheet, 3 177, 337 
es of lower till, 287, 308 
Adhémar’s theory, . 18 


Agassiz, Mt. . i 210, 213, 236 
“Prof L. , theory of continent- 
al ice-sheet, 4; on kames, 174; on 
local glaciers, 231, in Bethlehem, 


234-238; on origin of modified 
drift, . 238 

Altitude of ice-sheet, 9 3203 ‘along 

rivers—see Heights. 

Alton bay, 129 

Ammonoosuc river—Lower, 29, 61- 
63, 213, 241; Upper, ; 138 
Amoskeag falls, 64, 95, 250 
a granite quarry, 179, 232 
Analyses of till and clays, 287, 333 
Ancient river-beds, 24, 29, 37, 40, 81, 
: 90, 98 


Andover, Mass., series of kames, 167-170 


Androscoggin a 138-141; valley 

glacier, 226-229 
Antarctic continent, ice- -covered, 5, 330 
Arctic fauna, : ‘ ‘i . 282 
Asar (kames), @. ‘ 12, 62 
Ascutney mountain, striz, "201; boul- 

ders from, 196, 263; boulders on, 272 
Ashuelot river, c 5 57, 67 
Astarte castanea, 166, 167 


Astronomical cause of glacial period, 5-9 


325; an 337 
Atlantic system of mountains, . 366 
‘* Backbone” of Long Island, 303 
Baffin’s bay, ; s 317; 322 
Baker’s river, . 72, 181, 223 
Balch pond, 148 
Ballard rock, ‘ 266 

VOL. III 49 


Page. 
Banks of Newfoundland, . 317 
Barbadoes pond, 17, 161 


Barber’s mountain, . 49 
Barriers of ice forming lakes, I 1, 65, 


II5-I1g, 175, 332; of modified 
drift, 53, 79, 251; of till, 216, 251 
Bartlett boulder, 269, 270 


‘* Bays” in lake district, 124 
Beach, ancient, of Winnipiseogee 

lake, 127, 138 
Beach - ridges, Ior, 172-174, 311; 

about the great lakes, 174, 332 
Bear Camp river, . 121, 146 
Beaver dams, « 313 
Beech pond, ‘Upper | 128, 252 
Bellows Falls, » 47, 53, 64 
Berlin Falls, ‘ . 140 
Bessel, Dr. Emil . 317, 319 
Bible hill, Claremont, - 196 


Black river, delta, A F 52 
Blackwater river, 113; valley glacier, 220 
Blue clay, 94, 131, 153-155, 158-161 


333-337 
Bluffs of modified drift, 36, 82, etc. ; 


of till, 293, 296 
Boar’s Head, « 173, 254-257 
Bottom-land, 21; see Zuterval. 

Boulder clay, . 9, 176, 258 
Boulderless areas, . 264 


Boulders, dispersal, 4, 237, 252-275, 
320, 339; carried by local glaciers 
of White Mountains, 239-249 ; gla- 
ciated, 9, 205, 260, 277-279, 286; 
angular, 10, 286, 301; unstable, 
262, 277; rocking, 271, 3573; rare 
or abundant, 264; large, 264-271 ; 
floated, 117, 158, 160, 162, 276, 
320; specimens, 273, 279; in and 
upon kames, 14, 43, 46, 107, 127, 


378 


Page. 
129, 148, 158, 162, 257; morainic, 
Stratford, 23, 217; Twin Moun- 
tain house, 62, 242; in sand and 
clay, 89, 104, 117, 276; from Mt. 
Ascutney, 196, 263; on "Mt. Wash- 
ington, 204, 207, 272; at Boar’s 
Head, 255; in Manchester, 259; 
in Hanover, 261, ane like ; in 
Hartford, Vt., + 262 
Branch river, Milton, 151 
Breakfast hill, Rye, 171 
Butler’s rock, Surry, 263 
Camera used in sketching, : 373 
Canadian highlands, 321, 331 
Cape Cod, 282, 300-303, 337 
Carter Dome, slide, : . 247 
‘© Notch,. : ‘ . 248, 340 
Cause of arctic climate, . . 5, 324 
Champlain period, 11-15, 155, 174, 
327, 331, 337; deposits, table, 176; 
lake, 94; clay, 155, 176 


Changes of Merrimack river, recent, 81 


a sea-level, 18, 173, 329-333 
Channels, deserted, 24, 29, 37, 40, 


81, 98; pre- glacial, 26, 53 
Chase rock, 264-266 
Cherry mountain, . : . 272 
Childs pond, Thetford, Vt., : . 36 
Churchill rock, 265 


Clay deposits about Winnipiseogee 
lake, 17, 131-137; near Hooksett, 
94, 3343; in Rochester, Dover, Ex. 
eter, and Plaistow, 153-155; gray 
and blue clays, 94, 153-155, 158— 

161, 333-337 


Clay point, Alton, 134 

‘* Pounds, Truro, Mass., 302 
Clear stream, . : : - 139 
Cleavage in till, . 258, 308 
Climate, glacial 5-9, 285, 323, 337 
Clouds, Lake of . 81, 204 


Coast district, 

Cochecho river, 
Coldest part of continent, : 
Compression of lower till under ice- 


170, 203, 2I1, 287, 306 
130, 151-154 
22 


sheet, 9s pe 
Concretions, 
Conglomerate, Triassic 274, oe 
Connecticut, striz, . 212, 214 


ng lake, 340; river, modi- 
fied drift, 19-61, 333; upper val- 
ley, 20-24; lower valley, 26; del- 
tas, 23, 29, 33, 42, 52, 54, 57, 59- 
61; dunes, 41, 51, 54, 56; kames, 
21, 29, 35, 43-48; recapitulation, 
59-61; valley glacier, 213-218 
Continental i ice—see /ce-sheet; stabil- 
ity of the continents, 18, 330 
Contoocook nee a glacial 
lake, 12, 115-119 


INDEX TO PART III, 


Page. 
Contorted strata, ‘ 35, 52, 311 
Cooper’s point, Hinsdale, ; - 57 
Coos, Upper and Lower . F - 26 


Coral islands, Proving depression of 


the sea, 18, 329 
Courses of striz, 122, 183, 202, 208 
212, 214 


‘Crag and tail,” i 
Cragin pond, Greenfield, 
Crawford house, 62, 142, 27 Be 
Croll’s theory of glacial period, 5-9, 
325-327, 329 ; of glacial motion, 322, 325 
Crotched mountain, : ; 232 


288, 293, 2 


Cuba mountain, strie, . 201 

Currents, oceanic, considered as 
cause of glacial parle, Ts 324} of 
kames, . 13 


Dana, Prof. James D. 11, 174, 212, 213 


214, 321, are a0 32 
‘* Dark plains,” seiasues 80 


Davis island, I 30, 136 
Dawson, Principal J. Ww. 155, 174 
Deception, Mt. 242 


Decomposition of ledges, : 
Deficiency of modified drift, . s 79 
Deflected striz, 121, 212, 214, 224, 306 
Deltas, 16, 23, 29, 33, 38, 4l, 52, 54, 
575 59-61, 72, 77, 79; Of glacial 
lake in Contoocook valley, 110, 118, 119 
Deposition, fluviatile 1 ae me 175; 


lacustrine, 161 
Depression of sea, . + 329-333 
Depth of drift, 292; of Winnipiseo- 

gee lake, . 120 
Dispersion of boulders, i 252-275; 

centres of, for ice-sheet, 319-324 
Distances along Connecticut river, 

59-61 ; along Merrimack river, 102 


Distances travelled by boulders, 256, 259 
261-263, 274, 320 

Distribution of till, . 9, 285-309 
Disturbances in modified drift, a 52, 311 
Dover point, . . 161 
Drift deposits, table of, 176; “three 
divisions, 285; total depth, 292 ; 


map, . 323 
Driftless area of Wisconsin, « 323 
“Drums” of till, 288, 307 
Dunes, 16; in Connecticut valley, 41, 

42, 51, 54, 56; in Merrimack val- 

ley, 73, 74, 78; in Peterborough, 

105; south-east of Ossipee lake, . 147 
East pond, 150 
Eccentricity of the earth’s orbit, con- 
Edmands, J. Rayner F 372 

sidered as cause of glacial period, 

6-9, 325 
Elephant rock, . 267 


INDEX TO 


Page. 
Elevation of land, as cause of glacial 
period, 7, 213, 324, 329, 3373 ap- 
parent, due to changes of sea-level, 18 
329-333 
» 301 
: ! © 245 
4, 178, 180, 195, 204 
206, 219, 223, 225, 227 


Elizabeth islands, 
Ellis river glaciers, . 
Embossed ledges, 


Ephraim mountain, Me., 227 
Equinoxes, precession of 6 
Erie clay, : : e : - 176 
Erosion by ice-sheet, 5, 8, 178, 285, 

308; by rivers, 15, 38, 52, 59, 7o, 

82, 124, 143, 333; by the sea, 303; 

by rivulets, producing irregular 

outlines, 41; total in state, includ- 

ing pre-glacial, 178 
Eskers (kames), 12 
Exeter river, . ‘ : 150, 164 

“« sienite boulders, . 264 
Exploration of modified drift, . 19 
Fairlee pond, . 35 
Fall mountain, : ; , > 63 
Falls, Fifteen-miles, 24-26; below 

do., 26, 39; on Sugar river, 50; 

Bellows, 53; Livermore, 72; near 

Bristol, 74; in Franklin, 77, 123; 

in Concord, 80; Amoskeag, 95, 

250; in Nashua, 99; on Contoo- 

cook river, 102, 106, 111; in An- 

trim, 119; on Androscoggin river, 

140; on Salmon Falls river, 150 
Faults in modified drift, . ‘ 39, 107 
Faunas, . " - 282, 284, 338 
Fifteen-Miles falls, . 24-26 


19, 173, 350, 352 

117, 158, 160, 162 

276, 320 
Flood-plain, present—see /ntervals; 
of Champlain period—see Plains; 


Flint, William F. 
Floated boulders, 


intermediate, ‘ : ‘ 49, 58 
Floods of the Champlain period, 3, 328 
Flumes of White Mountains, . Fe 
Flume boulder, 269; mountain, » 278 
Fluvial deposits, 243, 338 
Folded layers of clay, 35, 52 


Formation of till, . F 5 Q, 285 
Fossils, 18, 38, 83, 163, 165-167, 281, 282 


326, 337 
Fractured ledges, 2 - 178 
Franklin, Sir John . - 320 
French pond, Haverhill, . i 30 
Frost, fracturing ledges, 179; action 
on Mt. Washington, + 207 
Fuller,C. B. . F . 281 
Furrows—see Strzg; lunoid, 182 
Gaps in Connecticut kame, 46 


PART III, 379 
Page. 
Geikie, on cause of glacial period, 

5; on kames, 14,174; on glaciated 

stones, 205, 279; on ‘‘drums,” 288, 

307; on till and intercalated beds, 326 
Geodetic positions determined by U. 

S. Coast Survey, . . . - 375 
Geological map, j : 2 371 
Giant’s grave, . : 3 : @ 162 
Glacial drift, 9, 10, 176, 286, Chap- 

ter II; sections, 290; depth, 292; 

map, . 323 


Glacial periods, indications of, 4, 28, 
285; cause, 5, 314, 324; date and 
length, 6, 327; order of events, 
337. See lce-sheet. 

Glacial periods, indications of for- 
mer. : 6, 274, 283, 285 

Glacial rivers, 11-14, 44, 303; sub- 
glacial, é ‘ . 308, 318 

Glaciated stones, 9, 205, 260, 277-279, 286 

Glaciers, local, 212, 215, 236, 239, 

337; latest, 230-249; in Bethle- 
hem (Agassiz), 234; in the White 
Mountains, 239; in Vermont, 250; 
in Greenland, 5, 315; in the Alps, 
4, 7, 314; in Scandinavia and 


Scotland (ice-sheets), . 315 
Glacis terraces, 33, 35 
Glen house, 3 ‘ 209, 210 
Gravel ridges—see Kames. 

Gravitation, causing marine submer- 

gence, . . s 18, 329-333 
Gray clay, 94, 153-155, 158-161 

333-337 
Great rock, Wentworth, . 271 
Green Mountains, striz, . 203 
Green Mountain Giant, 265 


: - 5, 8, 315-324 
9, 176, 205, 235, 282 
287, 292, 308, 318 


Greenland, 
Ground-moraine, 


Gullies in modified drift, Al, 46 
Gunstock mountain, striz, 201; boul- 

ders, 272; river, . é . 130 
Hall’s stream, . . » 20, 338 
Hardpan (lower till), 9, 176, 283 
Haverhill, Mass., series of kames, 170 


Hawes, George W. . 286, —336 
Hayes, Dr. I.J., 316; John L, ee oe 
Heights along Connecticut river, 59- 

61; along Merrimack river, 102; 

at Orange and Newbury summits, 

65; in the lake district, 103, 121; 

along Contoocook river, etc., 119; 

in Dover, 156; on Long Island, 
304; relative heights of land and 
sea, . . e 7 - — 18, 329 
Highest normal terraces, 16, 61, 103 
Hills enclosed by modified drift, 38, 

49, 96; of glacial drift, 287-309; 


of modified drift, 304. 


380 
Page. 
Hitchcock, C. H., chapter by, 177; 
on kames, ae Champlain clays, 155 
Hitchcock, Dr. E., on kames, 13, 
167, 1743 Mens mountain, 
197; Mt. Washington, 203; local 
glaciers, ‘ - 215, 240 
Holst, Dr. N. O., of Sweden, . = 4 
Horsebacks, - 176 
Horseshoe pond, Concord, : . 81 
Houston, Prof. E. J., é 268 
Hudson river, 94, 332; submarine 
channel, Z é 331-333 
Humboldt glacier, 5, 317 


Hummel, D., of Seg! : . 4 
Huntington, J. H. 138; on Cods 
county, 338; on Geology of Head- 


waters of ‘Androscoggin river, 358 


Ice accumulations, . 
Iceberg theory, 


« 312 
178, 195, 197, 215, 
238, 262, 284, 324 
Icebergs, origin of . ; E 5, 317 
Ice-sheet, formation of, 7, 8,177; ex- 
tent and thickness in America, 5, 
301-305, 320, 323, 330; in Europe, 
315, 330; effect in gravitation, 18, 
329-3333 motion, 5, 7, 177, 202, 
207, 208, 212, 285; retreat, 11, 65, 
92, 115, 121, 137, 149, 163, 174, 
175, 238, 305, 327, 337; reidvance, 
18, 163, 326; centres of dispersion, 
315, 319-324; ground-moraine, 9, 
235, 282, 287, 308; contained ma- 
terial, 10, 11, 15, 175, 292; termi- 
nal moraine, . + 301-305, 337 
Indian “ kettles,” 66; ‘‘ mortars,” 249 
«« Ridge, Andover, Mass., 167 
“* stream, - 20, 338 
Intercalated beds, 6, 17, 108, 125, 131, 137 
159, 163, 279, 289, 308, 337 
Inter-glacial periods, 6-9, 325-327 
Intersecting striz, 195, 196, 200 
ne 3 Il, 16; on Connecticut 
river, 21, 27, 29, 41, 52; below 
eben ane 63; on Pemigewas- 
set and Merrimack river, 72, 81, 
95; on Saco river, . 141, 143 
Iron, in lower till, 9, 286, 307; in 
upper till, ro, 286; in gray and 
blue clays, ‘ 3 33-3 37 
Isles of Shoals, , 275 
Isolated plateaus of modified drift, 21, 57 
Israel’s river, . : : = 23, 218 


Jackson, Dr. C. T. 64, 166, 173, 267 
Jacob’s brook, delta, 33, 42; boulders, 216 


Kames, defined, 12; synonyms, 12, 
176; origin of, 13, 14, 44, 91, 1743 


INDEX TO PART III. 


Page. 
sections, 14, 39, 43, 87, 107, 158, 
160, 172; boulders in and upon, 
14, 43, 46, 107, 127, 129, 148, 158 ; 
changing into moraines, 85, 88, 92, 
145; “authors who have treated of, 
174;—in Colebrook, 21, 339; at 
Wells River, 29; Connecticut 
series from Lyme to Windsor, 35, 
&c., 43-46; southward, 47, 48; 
near Fabyan house, 62, 277; near 
Orange summit, 64; at Little Sun- 
apee lake, 66; in Thornton, 71; 
in Franklin and Boscawen, 76; in 
Concord, 84, 259; Merrimack se- 
ries from Loudon to Manchester, 
85-92 ; in Hudson, 92; in Nashua, 
93; on Salmon brook, in Mass., 
99; in Peterborough, 104, 117; in 
Bennington, 106, Ilo, 116; in 
Henniker, 111, 114; near South 
Ashburnham, Mass., Io0, 115; in 
Tilton, &c., 124, 125; about Win- 
nipiseogee lake, 127-130, 138; 
Ossipee series, near Six-mile pond 
and along Pine river, 144-149; 
near Union Village, 151; near 
Farmington, 152; near Dover, 158- 
162, 257; Andover, Mass., series, 
167-170; Haverhill, Mass., se- 
ries, 170; in Newburyport, Mass., 
I7I1; on Cape Cod, 
Kame-like plains about Dover and 
southward, 17, 155-164, Mee 
at Plymouth, Mass., 


302 


301 


Kane, Dr. E. K. 5 
Kearsarge mountain, 181, 200, 220, 271 
Kilbura peak, . : : : » 53 
King, Clarence , 302 
Labrador, outflow of ice-sheet from, 
319-325; fauna, . ‘ 282 
Lafayette mountain, e 272 
Lake basins, 250-252 ; ramparts, 310; 
margins, 138, 340 
Lake district, 120-138, 203, 211, 224, 295 
Lake ridges, . » 174, 332 
Lakes held by ice-barriers, Ir, 65, 
115-r1g; lakes silted full, 23, 63, 67 


Lamination of the lower till, 2 58, a 308 


Laurentian highlands, 8, 320 
Leda clay, 166, 176 
Leda truncata, 166 


Ledges, rounded or embossed, 4, 
180, 195, 219, 2233 fractured, ae 
striated, ‘ 

Lee side, 

Lenticular hills of glacial acte, 10, 
69, 101, 176, 233, 254, 282, 287- 
309; origin, 307-309; slopes, 288, se 

308 


181 
180 


INDEX TO PART III. 


Page. 
Levelling, 19; heights determined 

Ves « 59-61, 102, 103, 119, 156 
Lewis, Elias, Jr., : . 208 
Limestone areas, 
hills, . : P 
Little Squam lake, . 

Little Sugar river, 
Little Sunapee lake, 


boulderless, 264; 

. 2 . 309 
126, 132, 138 
40, 51 
. 66 


Livermore falls, c «92 
Local glaciers, 212, 215, 230-250, 337 
Log in modified drift, . ; - 38 


Long Island, 172, 303-305, 331-333, 337 
Lovell’s mountain, striz, 201; boul- 


ders, . : ‘ 7 ‘ = 272 
Lower Ammonoosuc river, 29, 61-63, 
213; valley glacier, 5 . 241 
Lower till, defined, 9, 176, 258, 282, 
286; sections, 290; distribution, 
287; accumulation, 308; at Boar’s 
Head, 255; Hartford, Vt., 262; 
Portland, Me., 279; Lyndebor- 
ough, 283; lenticular hills, . 287-309 
Lull’s brook, delta, . 4I, 42 
Lunoid furrows, . 182 
Lyell, Sir Charles 62, 329 
Lyndeborough mountain, 207 
Macoma, ~ . 166 
Maine striz, 194, 211, 227, 229 
Magalloway river, 4 138, 225 
Magnetic variation, s . 121 
(Nearly all the bearings recorded 
in this report are referred to the 
true meridian.) 
Man, antiquity of . ‘ ‘ 328 
Manomet hill, : 3 F 301 
Maps of Connecticut river, 20, 24, 
40; of Pemigewasset and Merri- 
mack, Contoocook and Ashuelot 
rivers, 70, 96; of modified drift in 
eastern N. H., 146; of Andover 
and Haverhill series of kames, 
168 ; glacial map of North America, 323 


Marine shells, 18, 163, 165-167, 281, 
319; submergence, 18, I60, 165, 175 


238, 283, 319, 329 
Marshes, 3 ; - 101, 172 
Martha's Vineyard, . 5 . 302 
Mascomy lake, 216, 251; river, 40, 4I- 


Massachusetts, till in eastern, 10, 
299: strie, 195, 212, 213; local 


glaciers, 215; lenticular hills, 293 
299-301 

Masses of till in modified drift, 160 
McClintock, Capt. F. L., 320 


Meadow, é “i , 21 
Melting of ice-sheet, 10, II, 115, 121 
137, 149, 163, 174, 238, 303, 327 

331, 337 

Mer de glace, . 215, 318 


VOL, III 50 


381 


Page. 

Merrimack river, modified drift, 68- 

103, 333; kames, 71, 76, 84-93; 

dunes, 73; recent changes, 81; 
recapitulation, 102; valley glacier, 
218-222 
Merrymeeting river, 129, 137 
Mink brook, delta, . 38 
Moats or sloughs, . ‘ i 7 
Modified drift (Chapter I), defined, 
3,4; origin, 3, 11, 174, 238, 285, 
303 ; erosion of, 333; proof of ice- 
age, 28; contorted, 35, 52, 311; 
overlain by till, 17, 108, 125, 131, 
137, 159, 163, 276, 279, 290, 326; 


24 


hills and plains of, on Long Island, 304 
Mohawk point, ‘ - : . 125 
Molecular theory (Croll), @ 322,325 
Monadnock mountain, embossed 

ledges, 180; striz, a . 196 
Moose mountain, Hanover, . . 201 


Moosilauke mountain, 217, 223, 271, 287 

Moraine, ground, 9, 235, 282, 287, 
308, 318; in lenticular hills, 10, 
101, 254, 287-309; of boulders in 
Stratford, 23, 217, 339; in Haver- 
hill, 30, 31; at Twin Mountain 
house, 62, 242; in Littleton, 241; 
in Henniker, 112, 114; below Mas- 
comy lake, 216; west of Red hill, 
231; on Rocky Branch and Ellis 
river, 245; on Wildcat brook, 246- 
249; of boulders, in Nottingham, 
266; North Conway, 269; in the 
Alps, 314; kames changing into, 
85, 88, 92, 145; terminal, 218, 
235, 236, 246; lateral, 236; me- 
dian, 235, 245; river, 243 ;—ter- 
minal, of continental ice-sheet, 
301-305, 337; latest, from local 


sliding of ice, . + 230-233 
Mountain summits, boulders on, 204-208 
271 

Mt. Pequawket, é : - = 3 
Mussel shells, fossil, 163, 166, 281 
Mya arenaria, : - 166 
Mytilus edulis, 166 
Naushon island, . é ‘ 301 
New Jersey, terminal moraine, 304 
Newberry, Dr. J. S., 174 
Newburyport ridge, 171 


Newfound lake, 75, 221, 252 


Niagara river, erosion since ice-age, 6 
Nine Islands, . . 7 x BB 
Nineteen-mile brook, 127, 138 
Nordenskiold, : . ‘ + 316 
Normal terrace, highest, 16, 61, 103 
North Branch, Antrim, . IIg, 222 
Northern Railroad summit 63, 181, 219 
Nowell, W. G., . - 247 
Nulhegan river, 218 


382 INDEX TO 
Page. 
Oliverian brook, 31, 217 


Orange sand, a : 323 
Orange summit, 63-65, 181, 219 
Order of glacial events, 337 
Ordination rock, 269 


Ossipee lake, 121, 123, 146, 149) 231; 

mountain, 231; river, . 14 
Ossipee series of kames, . 144-149 
Ox-bow at Haverhill, « 29 
Packard, A. S., Jr., 182, 209, 210, 234, 
ais aa 319, 324 


Panoramic views, 372 
Passumpsic river, 28, 213 
Patterson, Capt. C. P. « 375 
Pawtuckaway mountain, . 222, 265 
Peabody river, 141, 209, 226, 246 
Peat-bogs, 98, 151, 167 


Pebbles in gray clay, 154, ee, 160; 
in kame at Dover, 257; in kame at 
Concord, 259; in kame at Hanover, 

Pemigewasset river, 68 ; valley glacier, 

221, 

Pennichuck brook, 

Pequawket rae and ‘brook, 144 3 boul- 


der, . 268 
Pierre-a-bot, 265 
Pine cones, ‘fossil, ‘ 18, 163 
Pine plains, 26, 71,77. 81, 145 
Pine river and pond, - 147-149 
Pinnacle, Hooksett, - 94 
Piscataqua river, 149-166 
Piscataquog river, . ‘ 90, 96, 114 
Plains of modified drift, 15 ; on Con- 

necticut river, 21, 26, 35, 56; on 

Lower Ammonoosuc river, 63; on 

Ashuelot river at Keene, 67; on 

Pemigewasset and Merrimack riv- 

er, 69, 72, 78, 80, 94, 95, 97: 993 

at Greenfield, 108, 116; on Con- 

toocook river, 109, 113, 114; on 

Saco river, 143; about Ossipee 

lake, 145, 149; in Rochester, 151; 

in Kingston and southward, 165; 

on Cape Cod, 302; on Long Is- 

land, 304; kame-like plains about 

Dover and southward, Ws aes 
Planished ledges, . 180 
Pleasant mountain, Me., . 202 
Pleistocene deposits, 176 
Plum island, Newbalypers, 101, 172, 173 
Polaris bay, . , 317, 319 
Polished ledges, - 227 
Pompanoosuc river, 37,45 
Ponds, - 252, 301 
Porphyritic gneiss, boulders, 264, 271, 272 

274, 291 
Portland & Odgensburgh Railroad, 142 
275-277 


Portsmouth, Great Falls & Conway 
Railroad, 2 144, 151 


PART EI, 


Page. 
Post-Pliocene deposits, 
Pot-holes, 3 
Powow river, . 


é - 176 
64-66, 178, 249 


‘ 150, 165 

Precession of equinoxes, . : 6 
Pre-glacial channels, 26, $3 
Prescott, Hon. B. F. . . - 264 

et Dr. William, on recent 

changes of Merrimack river, 81 
Profile of the Connecticut kame, 45 
Purgatory falls, 250 
Quaternary deposits, 176 
Quebec province, striz, . 194 
Quechee river, delta, 4I, 42 
te railroad cut, 262 
Ragged mountain, strie, 200, 220 
Ramparts of lakes, . 310 
Rangeley lakes, 225 
Rattlesnake island, 120, 136 


Recapitulation of modified drift of 
Connecticut river, 59-61; of Mer- 
rimack river, 102; of Chapter I, 

Recent or terrace periods, 

338 


Red hill, . . 120, 132, 231, 237, 272 
Relative heights of land and sea, . 18 
32 
Remnants of the Connecticut mee 
; : ; 47, 48 
Review of modified drift along Con- 
toocook river, 114-120; of the lake 
district, 136-138 ; of Saco river and 
Ossipee basin, 149; of the Cham- 
plain and Terrace periods, ° 
Rivers upon the ice-sheet, 11, 303, 
304; deposition of kames, 13; sub- 
glacial, 14, 44, 308, 318 
River-beds, ancient, 24, 29, 37; 40, 81 
99; 9 
180, 204, 235 
I2I, 250-252 
at” 357 
5 


176 
15, 175, 333 


174 


Roches moutonnes, 
Rock-basins, 
Rocking-stones, ; 
Ross, Sir J. C., antarctic ice, . 
Rounded ledges, 4, iB, ci 219, 223 
Runaway ponds, 251 


Saco river, 142-144, 149, 243 val- 


ley glacier, 229 
.Salmon brook, Nashua, 99 
s¢ Falls river, . 150 
Sawyer, Joseph B., . 156 
Saxicava rugosa, 166 
ts sand, 166, 176 
Saxton’s river, . 54 
Scandinavian ice, . 315 
Scotland, till, 307, 326; ice- -sheet, 315 


Scratched ledges and boulders—see 
Stria. 
Sea, changes of level, 18, 160, 165, 


173, 238, 283, 319, 329-333 


INDEX TO 


Page. 

Sea-coast, modified drift near, 17, 170-174 
“« walls, . 2 311 
Seal, fossil - . 165 
Sections, Connecticut valley, 21, 23, 
28, 29, 321 37, 39s 40, 51, 52, 50; 
Merrimack valley, 70, 73, 79. 95; 
98, 99; of modified drift under 
till, 108, 131, 132-135, 159; of 
gray and blue clay, 153, 158-160; 

of kames, 87, 107, 158,160; near 
Dover, 157-162 ; of till, 108, 13I- 
137, 755» 2855 290 


Segregated veins in sand, 39 
Serpentine boulders, 273 
Sewall’s falls, 80; island, - 83 
Shaler, Prof. N.S. 3 . 288, 307 
Shawshin river, ‘ - 167, 168 
Shells, 18, 163, 165-167, 281 
Shoals, Isles of P : . 295 
Six-mile pond (Silver lake), 144, 146 


Slides of land, 3 -- 240, 247, 312 
Slope of ice-sheet, 7; 320; of highest 
terraces, 5 61, 63, 103, 143 
Slopes of till, 249, 288, 306, 303 
Sloughs or moats, 2 24 
Smith’s river glacier, ‘ » 219 
Snow-fall, building up ice- “sheet, 5 8, 325 
“line of perpetual . 9 


Soapstone boulders, 273 
Soucook river, 86 
Souhegan river, 100, 116 


South, south-east, ‘and south-west 
courses of strize, 202, 208, 210, 212, 
214, 319, 320, 323, 
Spectacle pond, Meredith, : 


Spruce swamp, Fremont, 165, ie 
Squam lake, 126, 132; river, 126 
Stability of the continents, 18 
Station pond, Springfield, 252 


18, 174, 208, 319 
sg 332, 337 
. 180 


St. Lawrence valley, 


Stoss side, . 
Stratification, horizontal . 


. a-5' 
Striz, 4, 181-203, 212, 285, 288, San 
about Winnipiseogee lake, 122, 
224; on Monadnock, 197; on 
walls of ledge, 195, 223, 227, 229; 
intersecting, - 195, 195, 200 
Striated boulders, g, 260, 278, 286 


Stumps covered by the sea, « 173 
Sub-glacial rivers, 14, 44, 308, 318 
Submarine channel of Hudson river, 
329-331 
18, 160, 165, 238 
283, 319, 329-3 
Sugar Ball bluff, Concord, a ind o 
“¢ river, 49, 50, 216, he 
Sunapee lake, . 66 
Sweden, lower and upper “till i in, 10; 
ice- sheet, 2 3 é 
Sweetser, M. F., 


Submergence by sea, 


315 
248 


- Terrace periods, 


383 


PART III. 
Page. 
Synonyms, 176 
Syrtensian fauna, 282 
Table of Connecticut terraces, 59-61 ; 
of Merrimack terraces, 102; of gla- 
cial and Champlain deposits, 176; 
of strie, 183-195; of sections in 
glacial drift, : + 290 
“Tail, crag and” 288, 293, 295 


Terminal front of ice-sheet, 
moraines, 


5, 11; 
+ 301-305, 337 
15, 175, 333, 338 
Terraces, 3, 15, 21, 27, 58, 82, 175, 
338; highest normal terrace, 16; 
slope and height of, on Connecti- 
cut river, 59-61; do., on Merri- 
mack river, 102; delta terraces, 
16, 23, 29, 33, 42, 52, 54; 57, 59- 
61, 102; glacis terraces, 33, 35; 
for the lowest terraces, see /xterval. 
Theory of continental ice-sheet (Ag- 
assiz), 4, 177, 320, 3373; of cause 
of arctic climate (Croll), 5-9, 325; 
of marine submergence due to 
gravitation (Adhémar), 18, 329- 
333; iceberg, 178, 195, 197, 215, 
238, 284, 324 
Till, 4, 258, 282, 286; formation 
and distribution, 9, 10, 235, 285- 
309; division, Io, 216, 255, 262, 
279-282, 289, 301; sections, 290; 
overlying modified drift, 17, 108, 
125, 131, 137, 159, 163, 270, 289, 
290, 308, 326; erosion through, 
26; masses of, in modified drift, 
160; lenticular hills, 10, 101, 254, 
287-309 ; slopes, 249, 287, 295, 
306, 308. See, also, Lower ti] 
and Upger till. 


Torell, Dr. Otto + 9, 10, 321, 326 


TOWNS, INDEX TO: 


Acworth, 4 293 
Albany, . 272, 275 
Alexandria, 220 
Allenstown, 70, 94 
Alstead, ; é 263, 293, 294 
Alton, 121, 128, 134, 137, 224, 286, 295 
Amherst, ‘ 93, 9, 100, 297 

Ke Mass., 300 
Andover, 200, 220, 296, 306 

eS Mass., -_ 167, 299 
Antrim, . 3 96, 110, 118, I1g, 222 
Ashby, Mass., ‘ 300 


Ashburnham, Mass., 
Ashland, 


we a) 126, 13: a 
Auburn, . : oe 


170 


384 
Page. 

Barnet, Vt., ‘ 5 abe 26, 28 
Barnstable, Mass., . 3 302 
Barnstead, 295 
Barrington, 298 
Bartlett, i 143, 244, 269 
Bath, . 24, 28, 63, 270 
Bean’s Purchase, 247, 274, 340 
Bedford, 70, 96, 297 
Bellows Falls, Vt., . 26, 47, 53 
Belmont, . 124, 222 
Bennington, 96, 106, 116, 232, 297 
Benton, 5 ae 271, 287 
Berlin, - 140 
Bernardston, Mass., ing 263, 300 
Bethel, Me., =, 228 
Bethlehem, 210, 233- 238, 24I, 309 
Bloomfield, Vt., 3 : 
Boscawen, « 765 76, 79; oe 
Bow, » 70, 87, 94 
Bradford, Vt., 2 « 24, 27, 33 
Brattleborough, Vt., » 40, 55, 56 
Brentwood, ‘ 146, 233, 298 
Bridgewater, 70, 72 
Bristol, 70,75 
Brookfield, 122, 202, 224, 232, 275 
Brunswick, Vt., . 20, 22 
Campton, 70;, 72, 22 
Canaan, . 64, 219, a 
Canaan, Vt., é 20, 21 
Candia, . . 222 
Canterbury, « 70; “a4, 78, 221 
Carroll, s ‘ - 242 
Center Harbor, 121, 126, 274 
Charlestown, . is 40, 47, 50 
Chelmsford, Mass., . . IOL 
Chester, . ‘ 170, 232 
Chesterfield, "40, 54, 274, 294 
Chichester, » 295, 296 
Claremont, 40, 48, 50, 196, 263, 293 
Clarkesville, ‘A 
Colebrook, “20, 21, 264, ne 
Columbia, 3 20, 22 
Concord, 69, 70, 79-84, 114, 221, 259 

275, 296 
Conway, . 143. 149, 181, 268, 284 
Cornish, . 40, 42, 48, 264 
Danbury, ¥ : s * 220 
Dalton, . ‘ ‘ - 24 
Deerfield, 221, 222, 233, 298 
Deering, . aes 110, 118, 297 
Derry, . 298 
Dixville, . 271 


Dover, 17, 146, 154, 155- 161, 257, ce 333 


Dublin, 197, 294, 306 
Dummer, : . 139 
Dummerston, Vt., . 40, 48, 55 
Dunbarton, 249, 296 


East Kingston, 146, 154, 299 


INDEX TO PART III. 


Page. 

Effingham, 148 hs 202, 231, 313 
Eliot, Me., 166, 298 
Enfield, . 212 
Epping, 270, 273, 284, 298 
Errol, 139, 226, 340 
Exeter, 154, 164, 298 
Fairlee, Vt., . 24, 33 
Farmington, 130, 152, 297 
Fisherville, i 80, 82 
Fitzwilliam, . - 204 
Francestown, . 232, 297 
Franconia, "68, 70, 225, 274 
Franklin, 69, 70, 74, 76, 123, 221 
Freedom, 146, 274 
Fremont, é 165, 170, 233, 271 
Fryeburg, Me., 143, 202 
Gardner, Mass., 300 
Gilead, Me., ‘ , «= 229 
Gilford, 121, 130, 138, 272 
Gilmanton, 222, 275, 295 
Gilsum, 216, 263, 267, 294. 
Goffstown, 271, 288, 296 
Gorham, . 141, 208, 226 
Grafton, . « QY9;232 
Greenfield, 96, 108, 116, 297 
Greenland, 162, 356 
Greenville, 297 
Groton, . 2 223 
Groton, Mass., ‘ 300 
Groveton, 5 , ‘ 5 ~ 22 
Guildhall, Vt., 20, 23 
Guilford, Vt., 179 
Hampstead, + 273, 208 
Hampton, 171, 173, 254 
Hampton Falls, . 299 
Hancock, - 96, 108 
Hanover, 24, 38, 46, 201, 212, 260, 270 
271, 312 

Harrisville, . 204 
Hartford, Vt., . "40, 46, 262 
Hartland, Vt., : 40, 46 


Haverhill, - 24, 27, 29, 212, 217 
Haverhill, Mass., 165, 170, 299 
Henniker, 96 III, 114, 296 
Hill, é ‘ 70, 76 
Hillsborough, - . 96, 111, 118 
Hinsdale, 26, 40, 56, ae 214, 263 
274, 294 
Holderness, ‘ 70, 72, 224 
Hooksett, 4 70% "88, 94, 221, 334 
Hopkinton, 96, 113, 114, 296 
Hudson, . - 74, 92, 96, 221 
Jackson, . 208, 245-249 
Jaffrey, 104, 197, 294 
Jefferson, . 206, 207 
Keene, 67, 96, 263, 273 


INDEX TO 

Page. 

Kensington, + 233, 299 
Kingston, : 146, 165, 298 
Kittery, Me., . i . 166 
Laconia, . . 125 
Lake Village, . 125 
Lancaster, ‘20, 23, 212, 218, 273 
Langdon, e 53, 263 
Lawrence, Mass., . . 169, 299 
Lebanon, nae aes 212, 216, 251, 261 
Lee, 162, 298 
Lempster, - 201 
Lincoln, . 69, 70, 225, 269, 275 
Lisbon, . « 635273 
Litchfield, 69, 74, 96, 97 
Littleton, 24, 63, 211, 273 
Londonderry, . - 70, 74, 96, 221 
Loudon, . F - 85, 222, 295 
Lunenburg, Vt., 2 ‘ 20, 24 
Lyman, ‘ 211, 252, 274, 312 
Lyme, .  -. 24, 35, 37, 43, 212, 312 
Lyndeborough, 250, 274, 283, 297 
Madbury, . 146, 161 
Madison, F 14, 146, 149, 212, 274 
_Maidstone, Vt., 3 20, 23 
Manchester, 70, 89, 95; 179, 221, 232 
250, 258 

Marlborough, 4 294 
Marlow, . 293, 356 
Mason, . , . . 297 
MclIndoe’s Falls, Vt, ‘ - 24, 26, 28 
Meredith, P 72, 121, 126, 271 
Merrimack, . eas 92, 96, oy 221 
Methuen, Mass. a 169, 299 
Milan, 140, 340 
Milford, 207 
Milton, 150, 151 
Monroe, . 24, 28, 211, 273 
Mont Vernon, . F : 250, 297 
Moultonborough, . 121, 126, 132, 224 
231, 310 

Nashua, . 93; hae 99, 221, 259 
Nelson, - 294 
Newbury, : : - 65 
Newbury, Vt., + 24, 27, 29, 212 
Newbury, Mass., + 299 
Newburyport, Mass., or, 171, 299 
Newington, 150, 164, 298 
Newmarket, . 162, 298 
Newport, 267, 271, 203 
Newton, . - 146,170 
New Boston, 3 + 273, 297 
New Durham, . 129, 137, 202, 232 
New Hampton, 70, 72, 73, 75, 122, 131 
ea 249, 253 

New Ipswich, 116, 202, 297 
New London, . 66, 296 


Northfield, 


79, 74 
Northfield, Mass., 


40, 57, 274 


PART III. 


Northumberland, 
Northwood, 
North Hampton, 
Norwich, Vt., 
Nottingham, 


Orange, 
Orford, 
Ossipee, . 


Pelham, . 
Pembroke, 
Peterborough, . 
Piermont, 
Pittsburg, 
Pittsfield, 
Plainfield, 
Plaistow, 
Plymouth, 
Plymouth, Mass., 
Portland, Me., 
Portsmouth, 


Provincetown, Mass., 


Putney, Vt., 


Raymond, 
Rindge, . 
Rockingham, Vt., 
Rochester, 
Rollinsford, 
Roxbury, 
Rumney, 

Rye, é 
Ryegate, Vt., 


Salem, 
Salisbury, 
Salisbury, Mass., 
Sanbornton, 
Sandown, 
Sandwich, 
Seabrook, 
Sharon, . 
Shelburne, 
Somersworth, . 


South Berwick, Me., - 


South Hampton, 


South Newmarket, 


Springfield, . 
Springfield, Vt., 
Stewartstown, . 
Stoddard, 
Strafford, 
Stratham, 
Stratford, 
Sullivan, . 
Sunapee, 
Surry, 
Swanzey, 


Tamworth, 


385 


Page. 

20, 23, 218, 267 
. 222 
162, 171, 173 
24, 371 279, 312 
233, 264-267 


63, 181, 219 
24, 33, 201, 213, 216 
146, 211, 231, 269, 295 


+ 273 
70, 74, 86, 95, 334 

96, 104, 117, 297 

» 24, 27, 32, 212 

20, 195, 273, 338 

202, 221, 284, 295 

49, 42, 293, 313 

146, 155, 165, 170, 299 
Py te 1s 223, 313 

. 301 

. 279-282 
Bay Ae) 298 
+ 303 

40, 55 


150, 


« 233,270 
104, 115, 294 
» 27, 40, 50 

151, 153, 297 
146, 152 

- 204 

72, 181, 223 
173, 298, 311 
24, 28 


146, I 50, 


170, 


: 298 
113, 200, 220, 296 
ol, 172, 173, 299 

: TSS TAS hs 221 

: . 170 

122, 132, 295 
. - 172 
+ 297 

195, 226 

150, 282 

165, 298 

170, 299 

- 162 


141, 
146, 
152, 


‘4 », 222;:253 
' - 26, 40, 50 
e 20, 21, 274 
294, 356 

202, 211, 297 
162, 270, 298 
20, 22, 217, 339 
. - 263 

a Z 66 

216, 263, 294 

67 , 96, 6 


145, 146, 224, 269, 309 


386 


Temple, . . 
Thetford, Vt., 
Thornton, 
Tilton, 

Troy, i 
Truro, Mass., . 
Tuftonborough, 


Tyngsborough, Mass., 


Vernon, Vt., 


Wakefield, 
Walpole, 
Warner, . 
Warren, . 
Warwick, Mass. a 
Washington, 
Waterford, Vt., 
Waterville, 
Weare, . 
Weathersfield, Vt., 
Webster, 
Wentworth, 


Westminster, Vt., 


Westmoreland, 
Whitefield, 
Wilton, 
Winchester, 
Windsor, Vt., . 
Wolfeborough, 


Woodstock, 
Woodsville, 


INDEX TO 


Page. 


116, 202, 297 

. 24, 35 

ae 71, 225 

. 124 

294 

x (302 

122, 127, 133, 138 
224, 295 

96, Ior 


+ 27, 40, 57 


147, 150, 211, 224, 275, 295 


40, 54, 263, 293 
96, 113, 200, 296 
213, 223, 251, 271 
: é = OG 


201, 222 


273, 296, 313 


"40, 48, 263, 294 
. 275, 309, 311 


40, 216, 263, 204 
35, 40, 43, 48, 201 
121, 128, 133, 138 

224, 295 
70, 181, 225 
26, 29 


Triassic conglomerate, 274, 283 
Tributary deltas—see Deltas. 

Trisback bill, . 50 
Twin mountain, 2 272 
Tyson, six months on ice ‘floes, + 319 
Umbagog lake, , 139, 225 
Unmodified drift, . 3, 176 
Unstable boulders in till, 262, 277 


Upham, Warren, chapter by, 3; on 
distribution of the till, 285; on 


changes of sea-level, 
Upper Beech pond, . F 
Upper till, defined, 10, 11, 176, 282, 


329 
128, 252 


286, 290; extent and depth, 286; 
at Boar’s Head, 255; Hartford, 


Vt., 262; Portiand, Me., 


2793 


Lyndeborough, 283; forming ter- 
minal moraines, 301-305; cover- 
ing lenticular hills, 309; over Cham- 


PART III. 


Page. 
plain beds, . : ‘ 2 « 326 


Valley drift, II, 15, 175, 176 
‘* movements, glacial, 209, 212-229 
Veins in sand, z : 2 . 39 
Vermont strie, 193, 194, 202, 211; 
local glaciers, 216, 250; boulders, 


265; hills, . » 309 
Vertical seams of modified drift, 290, 308 
Vessel rock, Gilsum, ‘ 3 . 267 
Vose, George L., 182, 209, 210, 226 

228, 234 


Wait’s river, - 33, 42, 264 
Walls, strize on, 195, 223, 2298 sea, 311 


Wantastiquit mountain, . 56 
Warner river, . . 3 «= 413 
Washington boulder, 176, 269 
“ Mt., covered by the ice- 
sheet, 5, 203-208 ; boulders, 2 272 
Weirs, 125, 126, 131, 138, 252, 275 
Wells in Manchester, 96; near Mel- 


vin Village, 133; in Wolfebor- 
ough, 133; in Greenland, 163; in 
North Hampton, 164; in South 
Berwick, Me., 165; in Rye, 171; 


in Tuftonborough, etc., » - 290 
Wells river, . aes i 29 
West river, 55; mountain, : . 56 
Weston, Hon. James A. . 2 156 
“«“«Whale’s oe Concord, 84, 259 
Wheelock, G. A., striae on Monad- 

nock, . 197-200 
Whetstone brook, delta, . . 55, 57 


White Mountains, 121, 149, 203, 212, 
234, 287; local glaciers, 238, 239- 


249; flora, . . 284 
White Mountain Notch, 62, 142, 229, 238 
‘© river, ancient bed, . 40 
«© River falls, . és a 39, 46 
Whittaker pond, Henniker, III, 114 
Wildcat brook, ‘ ‘ . 246-249 
Willand pond, F é . 17, 156 
Williams river, delta, . ~ §2 


Winchell, Prof. N. H., on kames, . 174 
Winnipiseogee lake, modified drift, 
17, 103, 120-1383; 252, 310; strie, 

122, 224 

Winnipiseogee river, : - 77, 123 

Wright, Rev. George F., on kames, 

167-170 

Wukawan lake, . 126 


Young’s pond, Lyman, . : . 252 


“USAR MON TIT ‘puesuyp FT 


“NOLAVYD WOH TAYE aE 


L AL id 


Al DavVd 


PART IV. 


MINERALOGY AND LITHOLOGY. 


BY GEORGE W. HAWES, 


INSTRUCTOR IN MINERALOGY IN THE SHEFFIELD SCIENTIFIC SCHOOL OF YALE COLLEGE, 


THE MINERALOGY AND LITHOLOGY OF NEW HAMPSHIRE. 


INTRODUCTION. 


EW HAMPSHIRE is widely celebrated for its rocks and minerals. 
We read much in literature of its granite hills and its rocky peaks. 
Literary men and artists have, however, generally been satisfied to call 
the material of every mountain cliff, every boulder, the walls of every 
ravine, simply rock or granite; but, if one has stopped occasionally to 
notice the individual appearance of the rocks, and the many and mani- 
fest differences in them; has sometimes noticed in them the mineral 
crystals, often of rare beauty; or has searched among them for sub- 
stances of value,—he will certainly observe that in New Hampshire a 
wonderful diversity of minerals and rocks is found. Here are minerals 
of both economic and scientific interest, and rocks most widely different 
in composition and mode of formation; and it is the object of this report 
so to describe and classify the mineral productions of the state, that 
those who interest themselves in such studies may know and be able to 
identify the minerals and rocks by which they are surrounded. 
Mineralogy and lithology are economic sciences. A knowledge of the 
first enables one to detect the valuable products which can be extracted 
from the crust of the earth: a knowledge of the latter enables one to tell 
the value of rocks for building purposes, and the other uses to which they 
are applied ;—and although the manifest utility of these studies has always 
given them zest, yet it is hoped that many people, in this state so full of 
minerals, will be interested in reading the more purely scientific parts of 
this essay, in which the attempt is made to show, by simple means, the 


4 MINERALOGY AND LITHOLOGY. 


composition, mode of origin, and instructive peculiarities of our rocks 
and minerals. 

A rock is a mineral aggregate. It is a mass that is composed either of 
one mineral, or of a mixture of several. Hence, in studying the materials 
of the earth’s crust, we must begin with mineralogy ; and when we are 
familiar with the simple minerals, we can then study their aggregations, 
which form simple or complex rocks. In this work, therefore, the min- 
erals that have been found in the state will first be enumerated, and their 
noticeable peculiarities will be pointed out. The second part will be 
devoted to a description of the rocks. 

Minerals are often attractive and beautiful as specimens. Natural 
crystals and gems are admired by all. Rocks are generally admired as 
forming masses; but rocks are also beautiful when we study them with 
searching care,—when their minutest structure is brought into view by 
the aid of the microscope. Moreover, most instructive results are obtained 
by this method of study. Other portions of this geological report have 
treated of the age of our minerals and rocks, of their distribution and 
relations to one another, and of the structure of the country which results 
from the method of their arrangement. In this part, the results of labo- 
ratory work are given; and the methods of physical and chemical miner- 
alogy are introduced as a supplement to the work in the field. Micro- 
scopic work has been made prominent, since by this method of study 
such weighty results have been obtained by foreign laborers, that is has 
now become indispensable in the prosecution of geological work. The 
author’s aim has been to apply the newer methods of study to our old 
rocks; to try to show the value of those methods, and how many inter- 
esting things can be observed with their aid. He hopes that the many 
observations new to our section of country, and the variations here fur- 
nished on the observations made elsewhere, will be considered of value. 
He wishes to apologize for the incompleteness of the work, and the injus- 
tice done a grand series of rocks. Where the labors of a lifetime could 
not exhaust the observations that might be made, the work of a very 
short time, on limited material, can do but little more than draw the 
attention of students to this field of study. 

The author does not wish to enter on this work without paying his 
tribute to the German lithologists who have developed the methods that 


INTRODUCTION. 5 


he has employed, and so many of whose observations he has repeated. 
He hopes only to have added some facts of value from our country to 
the general store. 

I wish to thank Prof. Hitchcock for the opportunities and facilities that 
he has given to me for the prosecution of these studies. The people of 
the state are much indebted to Prof. George J. Brush, of New Haven, 
who has so kindly allowed his instruments and books, as well as all the 
resources of the scientific school, to be freely used for the benefit of the 
survey. I wish to render my personal thanks to my instructors,—Pro- 
fessors Brush and Dana, of New Haven, and Prof. A. von Lasaulx, of 
Breslau. The friendliness that these gentlemen have shown the writer 
made his studies peculiarly pleasant. 

In the pages that follow, I think all the things that are referred to and 
not explained will be found in Prof. Dana’s Mineralogy. I have, how- 
ever, been requested, by the chief of the survey, to elucidate my refer- 
ences to microscopic mineralogy, in order to make the work clearly intel- 
ligible to all. This will explain the introduction of so much elementary 
material upon this subject. 


MetTuops or Stupy. 


In the study of our minerals and rocks, only simple means and appli- 
ances have been employed. Many most complicated instruments, and all 
the appliances of large laboratories, are often employed in such studies ; 
but the means and instruments to which references are made in this 
work are within the reach of all. 

It is unnecessary to say anything about the chemical study. Refer- 
ences are sometimes made to the common blow-pipe tests. All the in- 
struments and reactions that are mentioned will be found described in 
any work on the blow-pipe.* In regard to the physical study it is also 
almost unnecessary to speak, since we have excellent treatises upon 
physical mineralogy; and the new work by Mr. E. S. Dana contains 
a very clear and concise statement of all those optical principles that 
are employed in investigating minerals. It is only because the applica- 


* See a treatise upon the blow-pipe, by Prof. Geo. J. Brush, published by Wiley & Son, New York. 
+A Text-Book of Mineralogy, E.5. Dana. Wiley & Son. 


6 MINERALOGY AND LITHOLOGY. 


tion of these principles is somewhat different when they are used in 
microscopic study,—and that, although a number of treatises have been 
written upon microscopic mineralogy, they are none of them written 
in English,—that a short description is here given of the methods of 
preparing specimens for examination, and of a microscope for examining 
them; to which is added a short statement in regard to what is to be 
observed, and of those points in which microscopic examination differs 
from the ordinary optical examination of minerals. 

When minerals occur in isolated crystals or masses, or when as con- 
stituents of rocks they are in grains or crystals of some size, all their 
physical properties are easily observed, and they can be subjected 
to chemical examination; but when minerals occur in complex, fine- 
grained aggregations, intimately intermingled, as they do in many rocks, 
none of the physical properties of the minerals can be observed, neither 
can they be isolated for blow-pipe examination. Hence, when a rock 
is fine-grained or compact in its structure, and the individual crys- 
tals are either invisible or unrecognizable, if we would study their 
nature, means must be devised to separate and identify them. To 
accomplish this result, many methods have been devised. A rock is 
sometimes pulverized, and any magnetic constituent that it contains Is 
withdrawn with a magnet. Sometimes in the powder a heavy constitu- 
ent is separated by virtue of its superior specific gravity; sometimes the 
ready solubility of a mineral in acid allows of its separation from the 
more insoluble constituents. These and other properties of minerals 
have often been taken advantage of to effect their separation ; but the 
most effective method of discovering the nature and composition of com- 
pact rocks is, to make very thin sections of them, and examine the sec- 
tions with a microscope, aided by certain contrivances for modifying the 
light. This is referred to at the outset, because this method is not 
merely employed in rock study, but it is now an essential feature of the 
study of minerals. By its help, the purity or impurity of minerals is es- 
tablished, as well as the nature and character of their impurities. More- 
over, the optical properties of many minerals can be most readily studied 
microscopically ; and the many other useful applications of this method 
are constantly increasing. As the method of preparing these sections 
of minerals and rocks for observation is not described in books that 


INTRODUCTION. 7 


are easily accessible to all, it will be here detailed; and it will be seen 
that, although the cutting of them is often thought to be difficult, it is in 
reality quite easy, and, with a little patience, can be done with no appa- 
ratus ;—therefore this beautiful way of studying rocks and minerals is 
within the reach of all who have access to a microscope. 


With a small hammer knock off from the mineral or stone to be examined a fragment 
nearly an inch in diameter, and as flat and thin as possible. Place some coarse emery 
(No. 60) upon a flat iron plate; moisten it with water, and then grind a flat surface 
upon one side of the fragment of stone. When a surface covering the whole extent 
of the piece has been obtained, grind it further upon another plate with fine emery 
(No. 120), and finally make the surface still smoother by grinding it with emery dust 
upon a glass plate; then wash and dry it. Take a piece of glass an inch and a half 
square and an eighth of an inch thick, and place in the middle of it a large drop of 
Canada balsam ; heat it gently over the smokeless flame of a lamp or a Bunsen burner, 
taking care that it does not inflame and become blackened by separated carbon. The 
balsam must be heated till so much of its volatile constituent is driven out, that, when 
cool, it will be so hard that an impression can be made in it with the thumb-nail with 
much difficulty. If heated less, it will yield to the subsequent pressure; if heated 
more, it will be brittle, and break. When the balsam has been sufficiently heated, 
allow it to cool until it begins to get gummy about the outside edges, then quickly 
scrape it up into a pile in the middle, and place the dry ground surface of the stone 
directly upon it, and press it down as firmly as possible against the glass, so that the 
surface of the stone and the glass may be as nearly in contact as possible. Then allow 
it to cool. No bubbles of air should be included between the stone and glass; and, if 
any of considerable size are seen, the operation should be repeated. Now, holding 
the stone against the iron plate by means of the glass, with coarse emery grind it until 
it is quite thin, so thin that you fear that the coarse emery will rend it; then grind it 
still thinner with fine emery, and then with emery dust upon a glass plate grind it as 
thin as possible, the rule being, that one should be able to read the type of a news- 
paper through the section. Sometimes, to attain this end with very opaque stones, the 
size of the fragment will be much diminished, and close watch must be kept upon it 
during the final grinding, else it might disappear before one expected it. The section 
is now made and ready to mount. 

The most convenient size of a glass slide to mount mineral sections on is 50 m. m. 
long and 28 m. m. wide. The long glass slides that are commonly used are very incon- 
venient to revolve upon the table of the microscope. In the middle of such a slide 
place some Canada balsam, and heat it till it begins to smoke. Having washed and 
dried the section, place a small drop of Canada balsam upon it, and heat it till it is 
loosened from the glass; then place on it a very thin glass cover, and with the point 
of a knife gently push the specimen and glass cover along together over the edge on to 


8 MINERALOGY AND LITHOLOGY. 


the warm balsam on the clean side; then, by pressing it down and working it back 
and forth with the knife-point, the specimen can be got into good position, and all the 
bubbles of air can be removed from between the two glasses. When the glass is cold, 
the superfluous balsam is removed as far as possible with a heated knife-blade, and the 
balsam that remains is washed away with alcohol, which dissolves it; and the section, 
on being wiped dry with a clean cloth, is ready for examination.* Fig. 1 represents 
the natural size of a finished section of one of our diabase rocks. 

The microscope that has been used in this work is one which was described by Rosen- 
busch.f The essential features of a microscope for the examination of mineral sec- 
tions, beyond -those required for ordinary microscopic work, are,—Nicol prisms, so 
arranged and attached to the instrument that the plane of vibration of the light which 
passes through them can be determined, and some arrangement by which a section of 
a mineral can be brought into position in the field of the microscope in any desired 
relationship to these planes. In the microscope mentioned, this is effected by con- 
structing a graduated circle on the mounting of each Nicol, and by placing a hair cross 
in the ocular. The tube and ocular of the instrument are not revolvable; and the 
adjustment for focusing is a vertical motion of one tube that slides up and down 
within another, but does not revolve within it; and if the zero of the graduated circle 
on the Nicol below the stage and the zero of the other that is placed over the ocular 
are both placed at the lines drawn upon the instrument for that purpose, the Nicols are 
crossed, and the two arms of the hair cross in the ocular correspond to the planes of 
vibration of the Nicol prisms. If now any section is brought into the field of the 
microscope, the relationship which the edges or cleavage lines of a crystal bear to the 
plane of vibration of the light which illumines it is shown by their relationship to the 
fixed hair lines in the ocular. In the excellent, inexpensive instrument that I have 
mentioned, a number of beautiful devices are introduced for the sake of making accu- 
rate work possible. A basal section of clacite can be placed on the ocular under the 
upper Nicol, or a quartz plate can be placed in the tube directly over the objective, 
either of which arrangements makes an excellent stauroscope of the instrument. To 
the applications of these, reference will presently be made. I have now mentioned 
the really essential arrangements that can, with a little trouble, be placed upon any 
microscope. 

Examination of Sectzons.{ The first point that will be noticed on examining a sec- 
tion of a mineral is its purity or impurity; and very often a mineral that is apparently 


# Those who enter extensively into the study of rocks usually use somewhat more expensive apparatus. A 
lathe which rotates a plate for grinding, and a disc for sawing, are commonly employed. It may also be men- 
tioned that some persons make a business of preparing such sections, and, with their experience, can make sec- 
tions in any given direction, through crystals or rocks, and can fulfil any specifications that may be made. Mr, 
L. Stadmuller, of New Haven, is one who prepares such sections; and Mr. Alexis Julien, of the Columbia Col- 
lege School of Mines, makes most satisfactory preparations. 


+ Yahrbuch fur Minereralogie, Geologie, und Palaeontologie, 1876, p. 504. 


{For a complete and systematic treatise on microscopic mineralogy, see Mikroskopische Physiographie der 
petrographische wichtigen Mineralien, von H. Rosenbusch. Stuttgart, 1873. See, also, Die Mikroskopische 
Beschaffenheit der Mineralien und Gestine, von Dr. Ferdinand Zirkel. Leipsig, 1873. 


INTRODUCTION. 9 


homogeneous will be seen to be so filled with matters foreign to its substance as to 
make a marked proportion of its mass. For example: at Hanover the schists are filled 
with pretty, perfectly crystallized red garnets. A section shows that these garnets en- 
close enough quartz, in little colorless grains, to make one third of their mass. Numer- 
ous other cases will be described in this work. The minute crystals, that commonly 
exist as impurities in other minerals, and which are so small that it is impossible to 
determine the name of the species to which they belong, are called crystallites. The 
nature of many of these crystals is suspected but not known. Zirkel divides them 
into bellonites, which are colorless, and trichites, which are black,—terms that have 
little use in the study of such minerals and rocks as ours. The microscopic crystals 
which exist as impurities, but which possess either form, optical characters, or other 
properties by which they can be determined, are called microlites. 

The cavities that minerals contain and the contents of them have been studied by 
many investigators. The microscope shows that crystals, either isolated or imbedded 
in rocks, are often filled with minute cavities, which contain fluids or crystals, or both. 
As the presence, and the nature of the contents, of these cavities give important indi- 
cations of the origin and former conditions of the crystals and the rocks in which they 
are found, they are worthy of careful attention. Our rocks furnish some remarkable 
examples of inclusions of this nature. Cavities containing water, and often salt crys- 
tals, and others containing liquid carbonic acid, are to be described. I have seen no 
rock which is so filled with cavities containing the latter fluid as one which has been 
found in the progress of this study; and sections showing this interesting inclusion 
may hence become readily accessible to all. : 

Crystalline Outlines. The first thing that will be noticed when unknown minerals, 
as they occur in rocks, are microscopically examined with reference to their determina- 
tion, is the outline of the sections of the crystals. Where crystals are cut at hap- 
hazard, as they usually are when scattered through a rock, it must be borne in mind 
that very variously formed sections can be cut from the same crystal. For example: a 
square, a rhomb, a triangle, or a hexagon can be cut from a dodecahedron. Yet, as 
the crystalline forms of imbedded minerals are commonly simple, and not subject to 
very much variation, the examination of the various sections of the same mineral that 
are commonly obtained in the same preparation, often enables one to form some judg- 
ment in reference to the form of its crystallization. Crystals are, however, often much 
distorted when found in the narrow confines of rocks; and hence very odd and striking 
outlines are met with, which are hard to refer to a crystalline form, and though plainly 
crystalline, as shown by their other physical properties, minerals have often no defined 
outline whatever, but exist as grains or irregular masses; hence experience and judg- 
ment are necessary in drawing conclusions from crystalline outlines. They are, how- 
ever, very helpful; and sometimes it is desirable to measure the angles of a crystal. 
In the microscope referred to, the stage is revolvable; the tube of the instrument is 
capable of being exactly centered, so that the revolution of the stage does not move 
the centre of the field of view; and then, by means of the spider lines in the micro- 

VOL. IV. 2 


10 MINERALOGY AND LITHOLOGY. 


scope, any angle of a crystal section can be measured by bringing first one and then 
the other side of the angle in coincidence with the one of the lines. The angle of 
revolution is read off upon the graduated circle that is made upon the outer edge of 
the disc-formed stage. Angles can be rudely measured by a Leeson’s goniometer, or 
by projecting the image on a sheet of paper, with a camera, and drawing it, and meas- 
uring the angle with an ordinary arc of a circle. 

Cleavage. One of the most valuable aids in determining a species is the cleavage 
that minerals show in sections. Minerals that possess characteristic cleavage always 
show it; for, if it does not exist in microscopic lines originally, it is certain to be de- 
veloped by the process of grinding. For example: hornblende and augite are easily 
distinguished by their cleavage; for, as the cleavages of hornblende parallel to the 
faces of the prism cross one another at 124°, the corresponding cleavages in augite 
cross one another at a right angle. It is plain that augite might be so cut as to givea 
section with an obtuse cleavage angle; but, as there are commonly some sections that 
show the relationship of the section to the form of the crystal, and as there is much 
difference in the ease and perfection of the cleavage of the two minerals, this feature is 
very valuable. In other cases, such as in the micas, the observation of the perfect 
cleavage is equivalent to a determination. Its almost entire absence, as in the case 
of olivine, is well-nigh as valuable for the identification of a species. 

Optical Properties. When a beam of light passes from a lighter into a denser me- 
dium, it is broken or refracted, but, when it enters a non-crystalline body in which the 
particles are arranged about no definite lines, it proceeds on its course with no further 
modification than an alteration of direction. Such bodies are called single refracting 
bodies ; but crystalline bodies, being formed and held together by certain forces that 
have acted in certain definite directions, allow the light to pass through them, accord- 
ing to certain laws which are dependent on the structure of the crystal. These laws 
are very simply applied in the examination of microscopic sections; and by their aid 
the determination of the crystalline system to which a substance belongs is made easy. 
The optical principles, as applied to the examination of sections of minerals of the 
different systems, as seen under the microscope, are as follows: 

Amorphous Bodies. It has been stated, that for examination of sections, it is neces- 
sary to have a Nicol prism above and one below the stage, so arranged that the planes 
of vibration of the polarized rays that pass through them can be fixed in any given direc- 
tion. Suppose the planes of these two prisms to stand at right angles to one another, 
and to correspond with the spider lines in the ocular of the microscope: the light which 
passes through the lower Nicol will be reduced to a plane, and this plane will correspond 
with that plane in the upper Nicol in which light is totally reflected in passing through 
it. Hence, on looking into the microscope when thus arranged, the field of the micro- 
scope will be dark, since the light which passes through the first Nicol is cut off by the 
second. If, now, the section of any amorphous substance be introduced into the field 
of the microscope, it having no structural arrangement, cannot modify the plane of the 
light, and consequently the field of the microscope will remain dark. If, now, the 


INTRODUCTION. II 


4 


upper Nicol or analyzer be turned about 90°, the field of the microscope will become 
light, because the light passing through the lower Nicol or polarizer passes through 
the analyzer, also, under the same conditions. If now, again, the amorphous section 
is introduced, the field will be still light. In general, place the Nicols as we will, the 
light will not be modified by placing an amorphous substance between them. More- 
over, an amorphous substance shows no definite cleavage lines, or no crystalline out- 
line. In New Hampshire we live in a region of old crystalline rocks; and hence, with 
some rare exceptions, we have but little to deal with amorphous substances. 

Isometric Crystals. Isometric crystals being developed symmetrically in each of 
their three directions, the elasticity of the ether is the same in all directions; and 
hence, in isometric crystals, light passes in all directions and planes with equal ease, 
and this gives to them the same optical character as amorphous substances. Isometric 
bodies in their sections can, however, commonly be recognized as crystals, since they 
generally possess either a definite polygonal outline or cleavage lines. These bodies, 
which possess simply the power of single refraction, are called isotropic. 

Tetragonal and Hexagonal Crystals. The case becomes quite different when any 
other body except those mentioned is placed between the Nicol prisms. Tetragonal 
and hexagonal crystals are not symmetrical in all directions; and hence the elasticity 
of the ether is different in different directions. It is either greater or less in the plane 
of the vertical axis than it is in the plane of the lateral axes; and, if a beam of light 
passes through a section of one of these crystals, which is cut parallel to the vertical 
axis, its vibrations will, in passing through the crystal, take place in these planes of 
elasticity ; and, as the elasticity is greater in one direction than the other, that part of the 
ray, the vibrations of which take place in the plane of greater elasticity, will be retarded 
less than those that take place in the plane of least elasticity, which is at right angles 
to the first; hence the ray of light will emerge from the crystal having all its vibrations 
reduced to two planes, and one of these sets of vibrations will be in advance of the 
other by a certain amount, depending upon the nature of the substance and the thick- 
ness of the section. In other words, the crystal in this direction is double refracting ; 
and the law may here be stated, that the light, by its entrance into any double refract- 
ing section, is divided into two rays, each of which is polarized. The planes of vi- 
bration of these rays are at right angles to one another; and these planes corre- 
spond to the directions of the greatest and least elasticity of the ether in the section. 
Let us now suppose such a section to be introduced into the field of the microscope 
while the Nicol prisms are crossed. If we place it so that the vertical axis of the crystal 
is parallel to the plane of vibration of the light as it issues from the lower Nicol, the 
light will pass through the crystal without further modification, since the plane of 
greatest or least elasticity in the crystal section corresponds with the plane of vibration 
of the light; and, as the light meets the crystal in one of the two planes in which it 
can pass, the crystal does not alter it, and it is therefore, as before, cut off by the upper 
Nicol, and the field remains dark. If, now, we revolve the table of the microscope a little, 
so that the principal axis of the crystal does not correspond with the plane of vibration 


12 MINERALOGY AND LITHOLOGY. 


of the lower Nicol (as shown by the relationship of its edge or cleavage to the hair lines 
in the ocular), then the light to pass through will be divided into two sets of vibrations, 
one of which will correspond with the axis of greatest elasticity, and the other with the 
axis of least elasticity, their directions in this case being parallel and perpendicular to 
the principal axis. One of these sets of vibration is retarded more than the other; 
and now these two sets of vibrations, on being again reduced to one plane by the Nicol 
above the ocular, are in condition to interfere with one another, which they do, pro- 
ducing color. If we continue the revolution of the table till we have turned it go°, 
then the other axis of elasticity corresponds with the plane of vibration of the light, and 
the field of the microscope becomes again dark; hence such a section, on being revolved 
completely around between crossed Nicol prisms, will be alternately light and dark four 
successive times, and it will be dark each time that an elasticity axis corresponds with 
the plane of vibration of the light, which, in this case, means whenever a crystallo- 
graphic axis corresponds with the plane of vibration of the light in either Nicol. 

The case is different if the section is cut perpendicular to the vertical axis. In 
the ordinary microscope the light reaches the eye in parallel rays; and hence, if 
such a cut is placed in the field of the microscope, the light passes through it parallel 
to the vertical axis. Now, as the lateral axes of tetragonal and hexagonal crystals are 
equal, the crystal is built symmetrically about this axis, and the elasticity in all direc- 
tions in this plane is equal; and hence in this direction a section of a mineral of 
either of these systems acts as an isotrope. It is dark between crossed Nicols, and 
light between parallel Nicols; and revolving it in a horizontal plane between the Nicols 
produces no effect; hence the direction through these crystals parallel to the vertical 
axis is called the optic axis; and, as there is but one direction in these crystals that 
has such peculiarities, these crystals are called uniaxial. 

If a basal section of a mineral of these sections is examined with converging light, 
as is well known, the light no longer passes through the crystal parallel to its optic 
axis, except in the centre of the field of view, but the rays pass through it more and 
more obliquely, according to the distance from the centre. Between crossed Nicols 
this results in the production of a series of colored rings and a black cross traversing it. 
In the Rosenbusch microscope the analyzer is placed above the ocular; and if now we 
take out the ocular and then replace the analyzer, of course the light that reaches the 
eye will be convergent. The field of view will be made small; but, in a basal section 
of an uniaxial crystal, the ring system and the cross will be seen very plainly, and, 
although the picture is small, it is very distinct. By the use of the microscope in this 
way, almost all the effects can be produced that are seen in instruments especially 
adapted for examination with convergent light; and, although Mr. Rosenbusch does 
not refer to it, the clearness and accuracy of the image, as seen in his microscope, 
I consider one of its features. By the use of higher powers, the light is rendered 
more convergent, and the ring system can be seen in quite thin sections, while 
with the lower power the optical properties of the plates that are commonly made for 
optical examination can be very nicely studied. Again: by the use of a quarter undula- 


INTRODUCTION. 13 


tion mica plate, the positive or negative character of uniaxial and biaxial crystals can be 
easily determined. This is an advantage for those who, on account of limited means, 
can possess but little apparatus; for, where, with a little trouble, an instrument can be 
so easily arranged, which will serve as a microscope, a stauroscope, and for the exami- 
nation with parallel and convergent polarized light, but little more is needed for optical 
study. Itis of course understood that crystals must have some size, in order to be 
thus studied. The optical properties of the minutest crystals can often be seen in the 
+ microscope; but when the ocular is removed, its magifying power is destroyed. 

The peculiarities of the hexagonal and tetragonal systems may then be summed up - 
to be, that all sections, except basal, when revolved in a horizontal plane on the stage 
of the microscope, the Nicols being crossed, are alternately dark and colored, being 
dark when the vertical axis corresponds with the plane of vibration of either Nicol, 
while basal sections are dark in all positions between the crossed Nicol prisms, save 
when examined by convergent light, when they exhibit a ring system traversed by a 
black cross. The tetragonal and hexagonal systems are distinguished from each other 
by the outline of the basal sections: tetragonal crystals having four or eight sides, 
while hexagonal crystals have some multiple of three as the number of their sides. 

-Orthorhombic Crystals. As the dimensions of orthorhombic crystals are different in 
all three directions, so the elasticity of the ether is different in each direction; yet 
orthorhombic crystals are so built that the axes of elasticity, and consequently the 
planes of vibration of the light as it passes through them, correspond with the crys- 
tallographic axes ; that crystallographic axis, in the direction of which the elasticity of 
the ether is greatest, is the direction of the axis of greatest elasticity; another corre- 
sponds to the direction of least elasticity ; and a third corresponds to the direction of 
mean elasticity. Hence the light, as it enters the section of an orthorhombic crystal 
cut in any direction, is broken and doubly refracted, and passes through the section in 
two sets of vibrations at right angles to one another, corresponding to the directions 
of greatest and least elasticity of the section; and these directions correspond with 
the directions which the crystallographic axes take through the section. 

If, now, any section of an orthorhombic crystal be brought into the field of the micro- 
scope between crossed Nicol prisms, whenever the direction of a crystallographic axis, 
as shown by the side of the prism or determined by the cleavage, is brought to corre- 
spond with the plane of vibration of the light, the section will remain dark, but will be 
colored when revolved away from this position, becoming dark again when it has been 
revolved go°. 

It is to be noted, however, that there are two directions through every crystal, with 
three different axes of elasticity, in which the two sets of vibrations, taking place at 
right angles to one another, have equal intensity. These directions lie in the plane of 
the greatest and least elasticity, and are called the optic axes; and, as there are two 
such directions, such crystals are called biaxial. If, now, a section be cut perpen- 
dicular to one of these axes, it is plain that, in parallel light, it will appear like an 
isotropic body. No interference of light will take place when it is placed between 


14 MINERALOGY AND LITHOLOGY. 


Nicol prisms, and consequently no colors will be seen. However, if such a section is 
examined between crossed Nicols in convergent light, as in the case of the uniaxial 
crystal, the optic axis will be surrounded by a series of colored rings; but in this case 
the ring system will be intersected by one black bar, and not by a cross, and when the 
crystal is revolved, this bar, instead of remaining stationary, as does the cross of uni- 
axial crystals, revolves, but in the opposite direction to that in which the section is 
revolved. 

The properties of orthorhombic crystals, when microscopically examined, are, then, . 
these: Any section is dark between crossed Nicols, when the direction of a crystal- 
lographic axis corresponds with the plane of vibration of the light, as indicated by the 
hair lines in the ocular. In every other position the sections are colored, with the 
exception of sections cut perpendicular to an optic axis, which act as if isotropic. Such 
a section can, however, be distinguished from an amorphous or isometric body, because 
it will be colored when the ocular of the microscope is removed in order to render the 
light convergent, and it willbe distinguished from an uniaxial section, because the field 
will be traversed by a black bar that revolves as the stage revolves, and not by a sta- 
tionary black cross. It may be remarked, that, when examining thin sections, the bar 
may be seen when the section is so thin that the rings have disappeared, for the number 
of rings that surround an optic axis depends on the thickness of the plate; and the plate 
may be made so thin that one ring may spread over the whole field, and then the field 
will be more or less light, but will still be crossed by a distinguishable bar. 

Monoclinic Crystals. Monoclinic crystals have three axes of elasticity at right angles 
to one another, but they differ from orthorhombic crystals in that, with one excep- 
tion, these axes do not correspond with the crystallographic axes. One of them 
always corresponds with the orthodiagonal; hence, sections in some directions through 
a monoclinic crystal follow the laws laid down for orthorhombic crystals, and others 
not. Sections parallel to the base, or the orthopinnacoid, or any other sections in 
this zone, will be dark between crossed Nicols when the crystallographic axes, indi- 
cated by crystalline edges or cleavage, correspond to the plane of vibration of the light 
that illumines them ; but all other sections will not be dark under these conditions, and 
must be revolved a certain number of degrees before they become dark, and this angle 
through which they must be revolved corresponds to the angle that the axes of elas- 
ticity make with the crystallographic axes in the given section. The measurement of 
this angle is often serviceable. For example: suppose we have sections of augite and 
hornblende cut parallel to the clinopinnacoid; when placed between crossed Nicols, 
with the vertical axis indicated by the cleavage placed parallel to the plane of the 
lower or upper Nicol, the sections will be colored, proving them to belong to an inclined 
system. In order to make them black, the augite must be revolved 39° and the horn- 
blende 15°. 

As the alternations of light and darkness furnish but an inexact method of measure- 
ment, its delicacy can be much increased by laying a calcite plate, cut perpendicular to 
the vertical axis, between the ocular and the analyzer; thus the interference figure of 


INTRODUCTION. 15 


such a plate in converging light is seen in the field; and when a crystal section is laid 
in the field of the microscope in such a position as to disturb the light, the black cross 
and rings are distorted, and do not reach their perfection again till an elasticity axis in 
the crystal corresponds with the plane of vibration of the light. This method of meas- 
uring the angle between crystallographic axes and elasticity axes is accurate, but it 
demands that the crystals have such dimensions as that the black cross can be seen 
upon them. For the study of long, narrow, and small minerals, Mr. Rosenbusch’s 
microscope has a quartz plate cut perpendicularly to the vertical axis, which can be 
inserted directly over the objective. The Nicols being crossed, the field will now be 
brilliantly colored, on account of the revolution of the light by the quartz plate. Any 
desired color can be obtained by revolving the analyzer; but the color selected will be 
modified if a section is introduced in such a way as to disturb the light. Suppose the 
quartz plate to be introduced, and the analyzer to be turned till we obtain a delicate 
violet color; then, if the section of a mineral is introduced into the field of the micro- 
scope, it will appear differently colored at all but at the exact point, whem-one of its 
axes of elasticity corresponds with the plane of vibration of the light, when it will 
be violet. The amount that the section must be turned from this point until the 
crystallographic axis corresponds with one of the hair lines in the ocular, will be the 
angle between the crystallographic and elasticity axes. 

The same holds true in monoclinic crystals cut perpendicularly to an optic axis, that 
was said in regard to orthorhombic crystals, save that these axes bear different rela- 
tionship to the axes of the crystal. As most microscopic observations are made with 
parallel light, the position of these axes is of less consequence in such study. The 
principal point is the position of the axes of elasticity. 

All the principles that have been stated will become plain on consulting PI. 2, Fig. 2, 
which represents two sections of augite from our trap rocks, as they appear in the field 
of the microscope in the positions to be dark between crossed Nicol prisms. Fig. 2a is 
cut parallel to the clinopinnacoid, and is bounded by the edges of the base and ortho- 
pinnacoids. If this section is placed with the vertical axis parallel to the plane of 
vibration of the light, the section will be colored, showing that an axis of elasticity 
does not correspond with the vertical axis,—hence the crystal belongs to an inclined 
system; but, on turning the section about in a horizontal plane 39°, it becomes dark. 
Now, according to Des Cloizeaux, the optic axes of augite lie in the plane of the clino- 
pinnacoid; they make an angle of 59° with one another, and their bissectrix, which is 
the axis of least elasticity in the crystal, makes an angle of 39° with the vertical axis ; 
hence, by revolving this section 39°, we have brought one of the axes of elasticity to 
correspond with the plane of vibration of the lower Nicol, and therefore the light is 
not broken, and the field remains dark. If, now, from this point we revolve the sec- 
tion, it will again be colored; but, when it has been turned 90°, it will again be dark, 
because the optical normal, or the axis of greatest elasticity in a crystal of augite, cor- 
responds with the plane of vibration of the light. If, however, we have a section 
parallel to the orthopinnacoid, this section will contain the orthodiagonal and the 


16 MINERALOGY AND LITHOLOGY. 


vertical axis at right angles to one another ; and, as the orthodiagonal is an axis of elas- 
ticity, in this position the crystallographic axes fall together with the axes of elasticity, 
and, on bringing these directions to correspond with the hair lines in the ocular, the 
section will be dark between crossed Nicols, as would a section of an orthorhombic 
mineral cut parallel to any pinnacoid. This relation is shown by Fig. 24, which rep- 
resents a section of augite cut parallel to the orthopinnacoid. On examining Fig. a, 
we see that one of the optic axes cuts the face of the orthopinnacoid at nearly a right 
angle. If, then, while examining section 4, we remove the ocular and replace the 
analyzer, thus producing convergent light, we shall see this optic axis, not in the centre 
of the field, for it does not pierce the face ata right angle, but we shall see it off on 
the side, as represented inc. The rings will be traversed by a black bar, which will 
revolve in the opposite direction to that in which we revolve the section. These three 
figures will make plain all that has been said in regard to the microscopic examination 
of crystals with polarized light. 

Sections of monoclinic crystals differ, therefore, from those of orthorhombic crystals, 
in that some sections (those that contain the orthodiagonal) will be dark between 
crossed Nicols when a crystallographic axis is parallel to the plane of vibration of the 
light, while the others will not. 

Triclinic Crystals. The light also passes through triclinic crystals parallel to three 
axes of elasticity, which are at right angles to one another; but in no case does 
one of these axes correspond with a crystallographic axis. Therefore no section of 
a triclinic mineral is dark between crossed Nicols when a crystallographic axis falls 
together with the plane of vibration of the light, but all become dark when revolved 
from this position a certain number of degrees, dependent on the mineral and the rela- 
tion of the section to the axes of the crystal. This uniform behavior of triclinic crys- 
tals serves well for their identification. 

Absorption and Pleochroism. Dependent upon the difference in the elasticity of the 
ether in different directions, through uniaxial and biaxial crystals, are the phenomena 
of absorption and pleochroism. For example: the rays of light passing through a 
beryl vibrating parallel to the vertical axis may have some vibrations absorbed, 
which will give to the emergent light a certain color, as, for example, blue, while 
that vibrating at right angles to the prism may have no rays absorbed, and thus 
emerge white. Again: the light, as it emerges from a section of a biaxial crystal, may 
be of three different colors or degrees of intensity, according as it vibrates parallel to 
one or the other of the three axes of elasticity. Therefore it is plain that sections of 
the same mineral may be quite different in color, depending upon their relation to the 
axes. For example: the hornblende in the schists of the Connecticut valley transmits 
light of three different colors. The color of any given section will therefore depend 
upon the resultant of the two sets of vibrations that pass through the section. If, 
now, we insert the polarizer without the analyzer, we can fix the plane of vibration of 
the light in any desired relationship to the crystal, and see what colored light is trans- 
mitted parallel toa given axis. In the case of this hornblende, we find that the light 


INTRODUCTION. 17 


vibrating parallel to the prism, emerges blue; that parallel to the orthodiagonal, green ; 
and that parallel to the clinodiagonal, yellow; hence, with the polarizer on the micro- 
scope in a section that contains several crystals, a crystal may have either one of 
these three colors, according to which axis corresponds with the plane of vibration of 
the light. For example, a basal section may be either yellow or green, and a prismatic 
section may be either blue, green, or yellow; and each one may be made to assume 
another color by revolving the section on the stage. If, now, we remove the analyzer, 
and observe with ordinary light, the basal sections will be greenish yellow, the result- 
ant of the two sets of vibrations parallel to the lateral axes, and the prismatic sections 
bluish green in the plane of the orthodiagonal, or green in the plane of the clinodiag- 
onal, the latter color being made by a union of the blue and yellow vibrations. This 
may be seen illustrated on Pl. 7, Fig. 2. 

The term pleochroism is reserved for the effect produced where certain colored rays 
are absorbed, as a beam of white light passes through a crystal, producing different 
colored emergent rays. An isometric crystal can possess no pleochroism. An uniaxial 
crystal may transmit two differently colored sets of vibrations, and can hence be di- 
chroic; a biaxial crystal may transmit three different colors, and hence may be trichroic. 

The term absorption, however, is reserved for that effect where much more light is. 
absorbed in one plane than in the other, producing, not a change in color, buta marked 
difference in the intensity of the light. This effect can also be best observed in the 
microscope when the polarizer and not the analyzer is affixed. Itis plain that a min- 
eral may exhibit both pleochroism and absorption at the same time, and that, with 
exactness, pleochroism is but a phase of absorption. 

All these principles are very concisely stated by Mr. Rosenbusch in the following 


form: 


I. The substance shows like optical properties throughout, or, if there are differences, 
the different parts are separated from one another by straight lines (twins).—A HoMmo- 
GENEOUS SUBSTANCE. 

1. All sections of the same substance, in all positions between crossed Nicols, 
appear dark. By revolving them on the stage of the microscope the light is not 
modified, and the interference figure of a calcite plate is not distorted.—Iso- 
TROPE. 

1*, The substance shows no traces of crystalline structure, neither in outline 
nor cleavage.—Amorphous. 

1>, The substance does show evidences of crystallization.—/sometric. 

2. All the sections, in all positions in a horizontal plane between crossed Nicols, 
are not dark, and may modify the calcite interference figure.—ANISOTROPE. 

28, The more or less regular quadratic sections behave like isotropic sections. — 
Tetragonal. Uniaxal. 

2». The hexagonal sections behave like isotropic sections.—Hexagonal. Uni- 
axial. 


VOL. IV. 3 


18 MINERALOGY AND LITHOLOGY. 


2°. No sections behave as if isotropic, but all of them become dark, and no 
longer distort the calcite figure when a crystallographic axis falls together with 
the plane of vibration of the light —Orthorhombic. Biaxial. 
24. For two of the crystallographic axes, this is no longer true.—Monoclinic. Bi- 
axial. 
2°, For none of the axes is this true.—Zrzclinzc. Biaxial. 
Il. Different parts of the substance act differently. In no position is the whole sec- 
tion dark between crossed Nicols; and the different parts bear no determinate relation- 
ship to one another.—AN AGGREGATE. 


Circular Polarization. Quartz is one of the commonest minerals that come under 
microscopic examination. A basal section of quartz, as is well known, possesses the 
property of circular polarization. Now, in microscopic sections, quartz is generally 
cut so thin that the revolution of the light is too little to be recognized, hence quartz 
behaves, in thin sections, like any other hexagonal substance. It is to be observed, 
however, that sometimes it is not necessary to make very thin sections, and, in such 
preparations, basal sections of quartz will not be entirely dark between crossed Nicols, 
though they will not show the succession of the prismatic colors. 


Of course it will be understood that the preceding pages contain no 
complete presentation of the principles involved in microscopic study. 
Enough only has been said to make the figures accompanying this report 
intelligible, and to draw the attention of those interested in the subject 
to the principles in accordance with which a microscope must be modi- 
fied, in order to do satisfactory study upon minerals and rocks; modifica- 
tion which, with little trouble, can be made upon any instrument, though 
perhaps not with the accurate working of those instruments that are 
made expressly for use in this now most important and fruitful study. 
It will be borne in mind, too, that the determination of minerals is not 
the only application of microscopic study, for most weighty conclusions 
have been drawn from the arrangement of minerals with reference to 
one another in rocks, and to the presence or absence of certain charac- 
ters and ingredients, for the recognition of which any microscope will 
suffice. 

The student of this department of mineralogy will find an extensive 
literature, and, as it is mostly foreign, he will therefore find in this coun- 
try a broad field for new investigation, where he will constantly be meet- 
ing with new beauties and interesting facts. 


CHAPTER I. 


THE MINERALOGY OF NEW HAMPSHIRE. 


s asai are in New Hampshire some minerals of economic impor- 
tance. There have here been found many minerals of great scien- 
tific interest, which have been studied both at home and abroad, and 
which have given to our state a world-wide reputation among men of 
science. In this chapter it is proposed to enumerate the mineral species 
that have been found in this state; to describe the peculiarities that they 
possess; and to give the results of whatever labor that has been done 
upon them. 

But little systematic work has heretofore been done upon our minerals, 
The final report of Dr. C. T. Jackson, the former state geologist, which 
was rendered to the legislature in 1844, contains what was known up to 
that time in regard to them. The labors of this geologist were largely 
devoted to the study of our mineral resources; and he was the first to 
call attention to many minerals and mineral localities which were for- 
merly unknown. Though the sanguine anticipations of that gentleman 
in reference to the mining wealth of New Hampshire have scarcely been 
realized, his labors are of no less value to us. 

The location of Dartmouth college in this state has done much for the 
development of our knowledge of our minerals. There have been in the 
past, as at present, gentlemen connected with this institution who have 
searched with great care through our rocks for minerals of new intérest. 
The labors of the present survey have added many names to our list of 


20 MINERALOGY AND LITHOLOGY. 


minerals and mineral localities, and, it is hoped, also something in regard 
to our knowledge of them. 

The minerals will be arranged in the same order as is adopted in 
Dana’s Mineralogy. This arrangement, which is based on the chemical 
composition of the species, is most convenient for a work of this kind. 
By this arrangement the different ores of the same metal, and: minerals 
allied together by the uses to which they are applied, are often separated 
from one another; but the chapter by Prof. Hitchcock, on economic geol- 
ogy, treats of the minerals from an economic standpoint. 

As this chapter on mineralogy is followed by a short treatise on our 
rocks, the properties and peculiarities of minerals as rock constituents 
are referred to under the proper heads. The microscopic characters of 
these minerals receive attention, since these characters are now of the 
most importance in the study of lithology. Thus, incidentally to the 
description of our minerals, an introduction to our lithology will be 
obtained. 

In the consideration of these minerals, it has not been considered nec- 
essary to encumber the report with descriptions of their ordinary physical 
and chemical properties, which can be found in any text-book; and there- 
fore, as a rule, nothing more than the formula of a mineral is given before 
proceeding to the mention of its individual characters as occurring in our 
state. The following species of minerals have been identified, and are 
referred to in the following order: 


Native Elements. 13. Sphalerite. 

1. Gold. 14. Chalcocite. 
2. Silver. 15. Pyrrhotite. 
3. Copper. 16. Pyrite. 
4. Iron. 17. Marcasite. 
5. Arsenic. 18. Chalcopyrite. 
6. Sulphur. Ig. Arsenopyrite. 
7. Graphite. 20. Tetrahedrite. 

Sulphides. fluoride. 
8. Stibnite. 21. Fluorite. 
9. Molybdenite. Oxides. 
1o. Argentite. 22. Water. 
11. Galenite. 23. Melaconite. 


12. Bornite. 24. Corundum. 


. Hematite. 

. Menaccanite. 
. Spinel. 

. Magnetite. 

. Chromite. 

. Chrysoberyl. 
. Cassiterite. 

. Rutile. 

. Pyrolusite. 

. Limonite. 

. Psilomelane, Wad. 
. Molybdite. 

. Quartz. 

. Opal. 


Anhydrous Stlicates. 


. Hypersthene. 
. Pyroxene. 

. Rhodonite. 

. Spodumene. 

. Anthophyllite. 
. Amphibole. 

. Beryl. 

. Chrysolite. 

. Garnet. 

. Zircon. 

. Vesuvianite. 

. Epidote. 

. Zoisite. 

. Iolite. 

. Chlorophyllite. 
. Biotite. 

. Lepidomelane. 
. Muscovite. 

. Anorthite. 

. Labradorite. 

. Andesite. 

. Oligoclase. 

. Albite. 

. Orthoclase. 


MINERALOGY. 


63. 
64. 
65. 
66. 
67. 
68. 
69. 


70. 
71. 
72s 
73- 
74. 
75+ 
76. 
77° 
78. 
79: 
80. 


81. 


82. 
83. 
84. 


85. 


86. 
87. 
88. 


89. 
go. 
gl. 
92. 
93- 
94. 
95- 


Microcline. 
Tourmaline. 
Andalusite. 
Fibrolite. 
Cyanite. 
Sphene. 
Staurolite. 

Hydrous Silicates. 
Prehnite. 
Analcite. 
Talc. 
Serpentine. 
Kaolin, clay. 
Pinite. 
Margarodite, sericite. 
Ripidolite. 
Penninite. 
Prochlorite. 


Delessite, Diabantite, Viridite. 


Columbate. 
Columbite. 

Phosphates. 
Apatite. 
Triphylite. 
Autunite. 

Tungstate. 
Wolframite. 

Sulphates. 
Barite. 
Melanterite. 
Kalinite. 

Carbonates. 
Calcite. 
Dolomite. 
Ankerite. 
Siderite, spherosiderite. 
Rhodochrosite. 
Malachite, 
Azurite. 


21 


22 MINERALOGY AND LITHOLOGY. 


1. Gop. 


Gold is a metal which, though widely distributed in New Hampshire, 
is not very often to be seen, since it has generally been found to exist in 
very minute scales or combined in sulphurets. The knowledge of the 
probability of its presence has led to the most careful search, and to its 
detection long ago in Canaan and Lisbon. From Canaan Dr. Jackson 
first obtained two recognizable spangles of gold by carefully washing 
2,000 grains of the quartz powder. It is also found, by assaying, in the 
pyrites of the same place. The most promising gold assay that I have 
seen, is one made by myself upon an arsenical ore from Crook & Brown’s 
mine in Lyman. The assay yielded 20 ounces of silver and 2.5 ounces of 
gold to the ton. Several other so-called gold ores were assayed at the 
same time, but with negative results, so far as proving them to be ores 
workable for gold. The appearance of these ores was certainly such as 
to excite suspicion of the presence of gold, and to make them well worthy 
of assay; but when such promising appearances are really so deceptive, 
all owners of such property cannot be too careful in the investment of 
means for working the claims. The assay mentioned shows the possi- 
bility of the discovery of workable deposits in our state. Productive gold 
mines have been operated at points on our coast from Canada to Georgia; 
but the history of gold mining in our section shows the necessity for 
much caution. 

Beside the gold contained in veins, the alluvial deposits over the whole 
course of the Connecticut river are liable to contain a little gold. Prof. 
Hitchcock has obtained it by washing the deposits at Hanover, and Mr. 
Huntington found it on the northern boundary of the state. At Pope’s 
mine, which is over the boundary in Canada, pieces have been found that 
weighed two grains. The region, however, that has excited the most 
attention, is the so-called Ammonoosuc gold field. This field was first 
reported on by Prof. Wurtz.* It contains gold not only in the alluvium, 
but also in the quartz veins in the rock. In Lyman specimens are found 
in which the gold is sprinkled through the quartz in grains that are visible 
to the naked eye, and in these veins it was first discovered. It is com- 
monly accompanied in the quartz veins by ankerite and galena. Lisbon, 


* Am. Your, Mining, Sept. 12, 1868. 


MINERALOGY. 23 


Littleton, and Enfield are other localities where gold is found. The 
whole subject of the explorations for gold and its distribution over the 
state is elsewhere given in detail by Prof. Hitchcock. It is evident, 
however, from what has been said, that gold is distributed and is liable 
to be found all over the western area of the state. 

Gold will flatten out when hammered, and will not dissolve or change 
color in nitric acid. These two simple properties of malleability and 
insolubility are very well known, even by those who forgetfully allow 
themselves to be deceived by yellow sulphurets and shining mica. It 
may be mentioned that the analysis of New Hampshire gold, which was 
made at the United States mint, shows that it is exceptionally pure, con- 
taining but one half of one per cent. of silver. Gold so pure is rarely 
found. 


2. SILVER. 


Native silver has been reported as found in New Hampshire, but still 
the occurrence of this mineral is not without doubt. Filaments of silver 
were found in an iron ore which occurs on West River mountain, and 
thus this place was put upon record as a locality of native silver ; but it 
has been questioned whether the silver was really native.* A piece of 
native silver, three or four inches in diameter, was found on a stone wall 
near Portsmouth, and this, too, was publicly reported. It may be stated, 
however, that the occurrence of native silver in this state has not been 
demonstrated. 


3. CoPpPER. 


Native copper is often found in connection with eruptive rocks, At 
Jackson in this state, on Eastman’s hill, while blasting for tin ore, some 
native copper was blown out by Jackson. It occurs at the junction of 
an eruptive mass of sienite with the slaty country rock. It was found 
in connection with other copper ores. Native copper, in dendritic forms 
between layers of the rock, has been observed by Prof. C. H. Hitchcock 
in Lyman and in Orford. 


4. Iron. 


The existence of native iron on the earth, save in the meteoric masses 


* Am. Four. Science, i, vol. 3, p. 74. 


24 MINERALOGY AND LITHOLOGY. 


which have fallen from above, has been often affirmed and often doubted. 
The subject has, however, received new interest from its proved presence 
in basaltic rocks, and from the discussion in regard to the origin of the 
numerous immense masses of iron which have been found in Greenland. 
My attention was called to this subject by observing a bright particle 
which was embedded in the midst of a grain of magnetite in a thin sec- 
tion of the chrysolitic gabbro from Mt. Washington. This particle pos- 
sessed a lustre so resembling metallic iron, that I tested it with a solution 
of sulphate of copper, and found that, like metallic iron, it became cov- 
ered with a film of copper, which proved it to be iron. On testing nu- 
merous other specimens, I was but twice able to repeat the observation ; 
hence, though no very great weight can be attached to the experiment, 
it may be said to exist in these rocks, and, if the undecomposed trap 
rocks from Waterville, or from the Mt. Washington river, are pulverized, 
the magnetic constituents withdrawn by a magnet, and these constituents 
treated with a solution of sulphate of copper, on examining with the 
microscope, occasionally one will see bits of reduced copper, which is 
evidence of the presence of metallic iron. The efficacy of this reaction 
has been doubted ; but my observation of grains of iron, though minute, 
is sufficient to call the attention of those who may study these rocks in 
the future to the possibility of finding it in more abundance, and under 
such circumstances that conclusions can be safely drawn from its occur- 
rence. 

No meteoric iron has, so far as I know, been found in this state. I 
might mention that a supposed meteorite, which was found in Concord, 
has been considered important from the circumstance that it contained 
no iron, this absence rendering it unique among meteorites. This stone 
was described by Prof. B. Silliman, Jr., in 1847,* and was shown to con- 
sist of tersilicate of magnesia and silicate of soda; but although the cir- 
cumstances of its fall seem to be well authenticated, it is but fair to state 
that in the cabinet of Yale college, where the specimen is preserved, it is 
put among the doubtful specimens. The reason of this doubt is, that its 
very peculiar composition, and its slaggy, artificial look, are thought to 
weigh seriously against its celestial origin. 


* Am. Four. Science, ii, vol. 4, p. 353- 


MINERALOGY. 25 


5. ARSENIC. 


Though ores of arsenic are common, native arsenic is a rare mineral 
in the United States, and almost its only localities are in New Hamp- 
shire. It has been observed by Jackson on the estate of Francis Kim- 
ball, in the town of Haverhill, and also at the tin mine in Jackson. In 

_ both these places it occurs in thin layers in a dark blue mica schist, asso- 
ciated with iron and arsenical pyrites. 

Native arsenic is volatile at a low temperature, and, when volatilized, 
gives forth its disagreeable but characteristic ordor of garlic. Dr. Jack- 
son, in describing its occurrence at Haverhill, states that on hot days 
it is somewhat volatilized by the heat of the sun striking upon the rocks 
where it is found, so that on such days the odor of arsenic is perceptible 
when one is near the locality. The garlic odor is evolved when the ore 
is struck with the hammer; but other arsenic minerals are like it in this 
respect. ¢ 


6. SULPHUR. 


Native sulphur occurs sparingly in some places, and results from the 
decomposition of iron pyrites. Pyrites, by exposure, is oxidized to iron 
sulphate, and this process is sometimes attended by the separation of sul- 
phur. It is in connection with pyrite and sulphate of iron that it is 
found. Thus associated, it has been observed in the iron ore beds at 
Brentwood. It has also been found in Chester in small quantities in a 
bed of tremolite, into which position it was probably conveyed by a pro- 
cess of sublimation. 


7. GRAPHITE. 


Graphite or plumbago is widely distributed through our rocks, as it is 
all over New England. Sometimes it forms large deposits; and some- 
times, in the form of scales, it is an ingredient of the rocks, at times 
forming a considerable proportion of their composition, and at times a 
mere microscopic impurity. In the towns of Nelson and Goshen it has 
been mined, although the quality is not of the best. 

Large specimens are found at Bristol. In Chester, it is found in veins 
in the mica slate. On the north side of Monadnock mountain, nodules 


with a coarse texture are found. At Sutton much is found, and of good 
VOL. III. 4 


26 MINERALOGY AND LITHOLOGY. 


quality. Other localities are Barrington, Bedford, Troy, Walpole, Wash- 
ington, Hillsborough, Campbell mountain, Keene, Wentworth, Swanzey, 
Andover, and Orford. 

This mineral possesses no peculiarities of note in this state. It is 
essentially pure carbon; it is opaque in the thinnest microscopic sections 
of the rocks which contain it. Caution must be exercised not to con- 
found the molybdenite, of which we have an abundance, with the graph- 
ite. They both soil the fingers, and leave a mark on paper. They are 
both infusible; but molybdenite, when heated before the blow-pipe, im- 
parts a characteristic green color to the flame, while graphite imparts 
none. 

The presence of graphite in the oldest rocks is regarded by many 
geologists as affording evidence of the existence of some form of life, 
either vegetable or animal, in those remote ages when the rocks were 
accumulated in which no fossils at present are to be found, since, by vital 
forces, free carbon is readily separated from its oxidized condition, and it 
is difficult to obtain it by other methods. The stages of transition of 
vegetable matter to coal, and finally to graphite, are well understood ; 
and the presence of animal remains, in considerable variety at some 
points in the Connecticut valley, renders it not at all improbable that sea 
weeds and other low forms of vegetable life may have had a great devel- 
opment in those previous ages in which the old schists were accumulated 
in which graphite is now so abundant. 


8. STIBNITE [Shy, S,]. 


This important ore of antimony has not been found in deposits of any 
economic importance in this part of the country. It has been obtained 
from Cornish and Lyme, though neither place should be recorded as a 
locality for the species, since no one is able to find it at present. Dr. 
Jackson assayed the specimens that he obtained from citizens in Cornish, 
and found they were very rich in silver, which was suspected to be due to 
an admixture of argentite. The specimens also contained copper pyrites. 
Prof. O. P. Hubbard found crystallized specimens in loose blocks of 
quartz in the town of Lyme, and though he supposed it to be in place 
near by, he was unable to find it. Hence it may be stated that there is 
evidence of the existence of this mineral, and a possibility of the discov- 


MINERALOGY. 27 


ery of localities. It is best recognized by heating a bit in an open glass 
tube, when it will be seen to fuse without difficulty, and to emit white 
fumes, which condense as an amorphous sublimate, while fumes of sul- 
phurous acid emerge from the end of the tube, recognizable by their 
reaction on litmus paper, and by their smell. 


g. MotyBvENITE [Mo, 8,]. 


This mineral, though not elsewhere common, has been found in abun- 
dance in this state. At Westmoreland there is a large vein of the massive 
mineral occurring in the crystalline rock, from which large amounts have 
been taken, and which has furnished specimens for every mineral cabinet 
in the country. At Landaff and Franconia it is often found in beautiful 
tabular hexagonal crystals, but ordinarily it is in a more massive condition. 
Fine crystals are found at Whitefield, Lyme, New London, and Alstead. 
Other localities are Orford, Newport, Warren, Jackson, Effingham, and 
Grafton. 

This mineral, when first found, was by some confounded with graphite, 
and, as graphite, the attempt was made to utilize it; but the crucibles 
that were made of it fell to pieces in the process of baking. Its lustre 
and streak are somewhat different from graphite, but it is easiest recog- 
nized by the green flame that it imparts to the blow-pipe flame. Molyb- 
dic acid is sometimes found associated with it as a decomposition product. 
This acid, which is a very valuable chemical reagent, is made by roasting 
molybdenite. 


ro. ARGENTITE [Agg, S]. 


A silver mineral once found at Cornish by Jackson was suspected to 
be argentite, but it was not proved. As silver sulphide exists in our 
galenas, it may possibly be found. 


11. GALENITE [Pb, S]. 


Galena is a very common mineral in New Hampshire. It occurs in 
small beds and veins, and though it has never been found in such large 
quantities as to make it a profitable lead ore, yet the uniform presence in 
it of varying amounts of silver has always made it a mineral of great 
interest, and numerous attempts have been made to mine it. It is well to 


28 MINERALOGY AND LITHOLOGY. 


bear in mind that no marked success has ever yet attended these opera- 
tions. The galenas that are found in these highly crystalline regions are 
often quite rich in silver; and, as rich ores have been found in this 
state, the zeal in searching for them has always been active. The trouble 
has never been that the ores were poor, but that the amount of ore 
was small and its extraction difficult; hence there are many places, as, 
for example, Shelburne, Warren, and Madison, where the surface indica- 
tions were flattering, and extensive operations were begun, but where 
the money expended was lost, and the workings long since abandoned. 
All over New England such abandoned mines are to be found. These 
facts should be remembered by those who are tempted to place great 
expectations upon every new discovery of silver-bearing ore, for experi- 
ence teaches that the success of silver mining in New Hampshire is so 
doubtful that no money should be expended in working veins, unless it 
is done under the advice of skilled and experienced scientific men. 

As localities where galena may be found, may be mentioned, in par- 
ticular, Madison, Shelburne, Warren, Enfield, Haverhill, Lebanon, Bath, 
Orford, near White pond in Tamworth, Meredith, Surry, Orange, Wood- 
stock, Rumney, Lyman, Lisbon, Dalton, Pittsfield, Loudon, Ellsworth, 
Alton, Connecticut lake, and Gardner mountain; and it may be stated 
to be common in small quantities scattered through the rocks in general. 

Galena can be recognized by its bright cubic cleavage planes, though 
at times it becomes nearly massive and intimately mingled with other 
sulphides, and at times it is merely seen as shining particles in the rocks. 
The following is an analysis of galena from Warren, by Jackson: 


Lead, a : : z zi ‘ ‘ ; a aes ‘ 83.48 
Silver, . 5 : , ‘ . ‘ " z i .20 
Sulphur, . 3 : : 3 : : ‘ 3 , - - 16.32 

100.00 


The ore of which this was a sample would yield 58 ounces of silver to 
the ton. Such an ore, under favorable circumstances, can be profitably 
worked. The galena from Madison was assayed by Mr. C. A. Seeley, 
and from that he obtained 94 ounces to the ton, a quite favorable result, 
so far as the quality of the ore is concerned. Assays of the ore that has 
been extracted from the Newburyport mine have been reported as much 


MINERALOGY. 29 


higher, and others much lower than this. Galena from Monroe, Conn., 
yielded Mr. P. Collier 874 ounces of silver to the ton. Thus these ores 
vary much in their value, and, though widely distributed, it may be quite 
safely affirmed that New England will never add any very great amount 
to the world’s production of silver. 


12. BorniTE [Cug, Fe, Ss]. 


This sulphide of copper occurs sparingly associated with other copper 
ores in this state. At Jackson it is found associated with the copper py- 
rites and the tin oxide. Large specimens of it are obtained from a metal- 
lic vein in Dalton; and at Shelburne it is associated with copper and 
zinc ores. At Littleton it is found in what is called the White Mountain 
mine, associated with chalcopyrite. It has not been found in crystals, 
but is generally in a massive condition, mixed with the yellow copper 
pyrites, from which it is easily distinguished by its color, which, on a 
fresh fracture, is between copper-red and brown; but, where it has been 
exposed, it is always tarnished to a purple color, on account of which it 
is called purple copper, or variegated copper ore. 


13. SPHALERITE [Zn, S]. 


There are some large deposits of sphalerite or zinc blende in New 
Hampshire, although thus far they have not proved themselves to be of 
economic value. At Warren there is a large vein of black blende. 
Blende, when pure zinc sulphide, is nearly colorless, but it usually con- 
tains some iron, which replaces a portion of the zinc, and the black color 
of this blende at Warren results from the presence of much iron. There 
is also a deposit of this black variety of blende in Shelburne, and another 
in Lyman, while at Madison there is a large vein of a much lighter col- 
ored blende, which, as might be supposed, contains very much less iron. 
Haverhill, Rumney, Monroe, and Croydon are other localities of note; 
and this is a mineral that one is constantly meeting in small quantities, 
in veins and crevices of the rocks, recognizable by its resinous lustre, 
though this property, usually so characteristic, is not easily seen in the 
black ferruginous varieties that are so common with us. In them, this 
resinous appearance is best seen on the spot, where a piece is struck 


30 MINERALOGY AND LITHOLOGY. 


with a hammer, or in the partially pulverized mineral. It has been pre- 
dicted that, at some future time, these deposits can be profitably worked. 

Some specimens of zinc blende from New Hampshire have been an- 
alyzed by Dr. Jackson, who obtained the following results : 


Madison. Lyman. Warren. Shelburne. 
Sulphur, A 2 i 33.22 33.40 26.60 32.60 
Zinc, ‘ : : : 63.62 55.60 62.50 52.00 
Tron, P ‘ F , 3.10 8.40 9.60 10.00 
Cadmium, ‘ ‘5 . .06 2.30 1.30 3.20 
Manganese, . . 5 Wasi ARE tae 1.30 

100.00 99-70 100.00 99-10 


The blende from Madison was yellow, while, owing to the amount of 
iron present, the others were all nearly black. All the analyses, save the 
one of the blende from Warren, correspond very nearly with the correct 
formula (Zn, Fe) S. In the analysis of the Warren blende, the amount 
of sulphur is too small, and this indicates some alteration of the mineral. 
The uniform presence of cadmium is very noticeable; and the Lyman 
and Shelburne blendes would be considered as very rich in this metal. 

The blende in New Hampshire is not often found in good crystals, but 
in its massive condition it usually shows on fractured faces the charac- 
teristic dodecahedral cleavage. 


14. CHaLcociTE [Cug, S]. 


This sulphide of copper is not common. At some places it accompa- 
nies other copper minerals, though in small quantities. At Oxford it 
occurs associated with the green carbonate of copper and with copper 
pyrites. It is not in crystals, but in noncrystalline masses and grains, 
recognizable by their dark gray color on a fresh fracture, and by the 
malleable copper globule, which is obtained by heating the mineral on a 
piece of charcoal with the blow-pipe. 


15. PyRRHOTITE [Fe;, S,]. 


This mineral is found in some places in veins forming large deposits, 
and it is also scattered all over the state as a constituent of the rocks. It 
has not been found in crystalline form, but it occurs in bronze colored 
masses, associated with other kinds of pyrites, from which it is distin- 


MINERALOGY. 31 


guished by its lustre, and the property of being attracted by the magnet 
in small particles, whence it is called magnetic pyrites. A large deposit 
of pyrrhotite occurs at Croydon, where there is a vein of the sulphurets 
of iron and zinc, having a width of several feet, two feet of the thickness 
of which is occupied by a very solid, compact pure pyrrhotite, and nearly 
two feet more by a less compact variety. It is also found in considera- 
ble quantity in Enfield, Orford, Haverhill, East Hanover, Lyman, Graf- 
ton, and at Mt. Misery. Small deposits are found almost everywhere. At 
Copperas hill, in Vermont, it is utilized in the manufacture of copperas. 
Dr. Jackson mentions that the Franconia Iron Company attempted to 
work the magnetic iron ore of Landaff, but that they failed to extract 
good iron on account of the large amount of magnetic pyrites that the 
ore contained, for sulphur in iron ore is very deleterious. 

When pyrrhotite is present in a section of a rock prepared for micro- 
scopic examination, it can be detected by shutting off the light which is 
transmitted through the section from below, and examining it by the 
light reflected from the surface of the section. Pyrrhotite, being a me- 
tallic mineral, will then appear bright in the dark field of the microscope, 
and can be recognized by its bronze color. Sometimes a little micro- 
scopic grain in our dioritic rocks will be partly pyrite, partly pyrrhotite, 
and partly magnetite; and their lustres are brought into sharp contrast 
in the field of the microscope. 

Sulphide of iron is commonly a very deleterious ingredient of building 
stones ; but the magnetic pyrites does not decompose so readily as ordi- 
nary pyrites. I have seen some gneiss from our state, in buildings, and 
though the stone was sprinkled with particles of magnetic pyrites, it had 
not become stained by long exposure to the weather. 

Pyrrhotite, in certain localities, contains such a percentage of nickel 
and cobalt that it forms a valuable ore of these metals. I have exam- 
ined some of the pyrrhotites of the state, and, although by a careful test 
nickel was detected in them, I have as yet seen none that would be con- 
sidered as an ore of that metal. 


16. PyriTE [Fe, §,]. 


Iron pyrites is another mineral that is very common, both in masses 
and as a constituent of the rocks. It forms a large proportion of the 


32 MINERALOGY AND LITHOLOGY. 


material of some metallic veins, as, for example, at Croydon mountain. 
Shelburne, Unity, Warren, Haverhill, Red hill in Moultonborough, Rich- 
mond, Lebanon, Lyme, Lyman, Gardner mountain, and Monroe may be 
mentioned as places where it is to be obtained in abundance, while hun- 
dreds of square miles of the state are covered with pyritiferous rocks, 
and it is common everywhere in little veins. It is often found in crys- 
tals, the prevailing forms being, as usual, the cube with the planes of the 
pentagonal dodecahedron. The crystals are often much distorted by the 
oscillation between these two forms. 

Pyrites is a very common ingredient in rocks ; and, as its presence is 
very deleterious in stones that are to be used for building purposes, a 
careful examination of them is advisable, as, if pyrites be present, it de- 
composes on exposure, and stains the stone. When present in consider- 
able amount, it can be recognized with the naked eye, since its brassy 
yellow metallic lustre makes it conspicuous; and the minutest particles 
of it can be recognized in microscopic sections by turning away the light 
from below the stage of the instrument, when the pyrites, with its bright 
yellow reflection, is very evident. In the slates and greenstones of the 
Connecticut valley, it is often found in the most minute microscopic and 


still perfect cubes. 
17. MarcasiTE [Fe, Sy]. 


This, the dimorphous form of iron bisulphide, has been found at 
Haverhill, associated with ordinary iron pyrites and the various other 
sulphurets that occur there. Marcasite is orthorhombic, has a lower 
specific gravity than pyrite, and, on account of its lighter yellow color, 
is called white iron pyrites. The Haverhill mineral is found in fibrous 
radiated masses. The crystalline form is not evident, but it is plainly 
prismatic. It decomposes more readily than common iron pyrites; and 
the outside of the fibrous masses is often changed into the hydrous oxide 
of iron. All these characters make it easy to distinguish, though its 
chemical reactions are like those of pyrites. 


18. CyaLcoryriTe [Cu, Fe, S,]. 


Chalcopyrite is widely distributed over the state in varying amounts, 
but never in such quantity as to make workable deposits, although open- 


MINERALOGY. 33 


ings have been made with the hope of profit in view. Chalcopyrite is 
found associated with other sulphurets in metallic veins, and also in little 
deposits on the walls of dykes, and in the surrounding rocks. It is usu- 
ally massive, but at times it shows evidences of crystallization ; and at 
Copperas hill, across the Connecticut in Strafford, very pretty crystals, 
formed by the twinning of two tetrahedrons, are found. As localities for 
copper pyrites that are noteworthy, may be mentioned Bath, Franconia 
(in gneiss rock), Madison, Haverhill, Warren (on Davis’s farm), Lyme (east 
of the east village), Jackson, Shelburne, Unity, Westmoreland, Littleton 
(with bornite in White Mountain mine), Connecticut lake, Croydon, Plain- 
field, Orford, Gardner mountain, and Monroe. 

A number of specimens of chalcopyrite from New Hampshire were 
analyzed by Dr. Jackson,* but, as most of the analyses are of impure 
specimens, which were selected as ores, they possess no value for a 
report on mineralogy. It is sufficient to say that Dr. Jackson found, by 
his analyses, a number of ores sufficiently rich to be profitably worked. 
Analyses of ores of copper from New England are, however, not at all 
conclusive as to the value of mines. The following is Dr. Jackson’s 
analysis of chalcopyrite taken from H. Lang’s estate in Bath. The an- 
alysis agrees very well with the formula, and indicates quite pure copper 
pyrites : 


Copper, .- : a ‘ ‘ : zi - . ‘ ‘i i 32.5 
Iron, . . = . . 5 . % é : . . : 33- 
Sulphur, . : : a - ‘ . - ‘ . ‘ 31.2 
Silica, : ; es se : fete oe : 3.2 
99-9 


When occurring as a microscopic impurity in the rock, chalcopyrite is 
recognized by the lustre, which is given to the light reflected from its 
surface. Its deeper yellow color distinguishes it from iron pyrites. It 
is not often met with in rock study. 


19. ARSENOPYRITE [Fe As S]. 


Arsenopyrite or mispickel is not an uncommon mineral in our state. 


* Geology of New Hanipshire, 1844, p. 215. 
VOL. IV. 5 


34 MINERALOGY AND LITHOLOGY. 


It is found massive, and also in beautiful crystals, that are well known 
to all mineralogists. 

The ordinary massive variety occurs abundantly. The quartzite and 
schists along the Connecticut river are often full of it, and it is sometimes 
an associate of the ores that have been proved to be auriferous. In these 
localities crystals of the ordinary form are also found. Large masses of 
the ‘non-crystalline variety are found at Jackson. Francestown, Haver- 
hill, Lebanon, Weare, Groton, Lisbon, Lyman, Middleton, and Alton are 
localities of note for this mineral. It is abundant in Rockingham county. 
The mineral, when crystallized, is commonly found in forms resembling 
Fig. 1 on Pl. 3. 

Arsenopyrite is orthorhombic in crystallization. The crystals that are 
found at Franconia are very remarkable for their form and for their per- 
fection. Some of them are represented on Pl. 3. The figures are taken 
from Dana’s Mineralogy. Figs. 1 and 1 4 represent the ordinary crystals 
as there found, while 1 4 is an exceptional variety, both in form and compo- 
sition. It was analyzed in 1833 by A. A. Hayes,* who, on account of the 
cobalt that it contained, considered it to be a new mineral, and named it 
danaite, in honor of Prof. J. F. Dana, who made known the locality, and 
who first detected the presence of cobalt in the mineral; but it having 
been shown that cobalt is at times present in varying amounts in arsen- 
opyrite, where it replaces a portion of the iron, Prof. J. D. Dana, in his 
Mineralogy, considers it to be merely a variety of that mineral, which is 
very evidently the case. The following is the analysis of the Franconia 
danaite, as made by Mr. Hayes: 


Arsenic, . 3 : ; 3 5 5 3 ‘ F . a 41.44 
Sulphur, . : . A 3 . A . . ‘ A 17.84 
Iron, - z 2 5 s 5 5 : ‘ . ; : 32.94 
Cobalt, . - . 5 . - - F ‘ é 5 6.45 

98.67 


These rare crystals are found isolated in the gneiss rocks, associated 
with chalcopyrite, and are highly prized by mineralogists and crystallog- 
raphers. 


* Am. Four. Science, vol. s, xxiv, p. 386. 


MINERALOGY. 35 


20. TETRAHEDRITE [Cu, Sb, S,]. 


This mineral, elsewhere so important, is very rare in New Hampshire. 
It has been found in Cornish, associated with stibnite; but the place 
from which the specimens were obtained is now unknown. 


21. FruoritE [Ca Fi,]. 


There are several noteworthy occurrences of fluor spar in our state. At 
the Notch it is found in beautiful sea-green octahedrons, of the size of 
hickory nuts and of perfect form. It occurs in the quartz veins. In the 
more exposed portions of these veins octahedral cavities are found, from 
which the fluor spar has been dissolved, and often these cavities are par- 
tially refilled with quartz, thus showing the process of the formation of 
pseudomorphs by replacement; for, if the process of filling had been 
complete, we should have octahedrons of quartz just like those that come 
from Cornwall. These green octahedrons are found on Mts. Crawford 
and Webster, at Bemis brook, and, indeed, all along the White Mountain 
Notch. Fluor spar forms a vein of considerable size at Westmoreland, 
from which crystals weighing several pounds have been obtained. The 
color is light green, and the crystals are cubic. It is also found at the 
tin mine in Jackson, where crystals of various colors—green, white, and 
purple—are found. A pretty purple variety is found associated with 
albite at Grafton, and also at Newbury. 

Fluor spar, when treated with sulphuric acid, is decomposed with the 
generation of fluor-hydric acid; but if a crystal with bright faces is placed 
in the cold acid for a short time, and then is removed, washed, and exam- 
ined with the microscope, it will be seen that it is not uniformly eaten by 
the acid, but that its surface is covered with little depressions bounded 
by crystallographic faces, which bear a definite relationship to the out- 
lines of the crystal, and are supposed to indicate certain structural lines 
according to which the crystals are built. If, now, one of these green 
octahedral crystals from the Notch is broken so as to obtain a fine 
bright cleavage surface, and is then submitted to the action of sulphuric 
acid, it is etched by the cold acid with the greatest ease, much quicker 


36 MINERALOGY AND LITHOLOGY. 


than any other crystals that I have ever tried ; and, when examined with 
the microscope, its surface is seen to be covered with depressions, one of 
which, with its relationship to the octahedral face, is shown in PI. 3, Fig. 
7a. These etch figures on fluor spar are considered by H. Baumhauer* 
as being made by the faces of a tetragonal trisoctahedron, because, if the 
cubic faces of fluor spar are etched, four-sided pyramidal depressions, 
first observed by Wyrouboff, are found on them, the sides of which are 
parallel to the combination edge of the cube and octahedron, and which 
can consequently also be explained by referring them to the same figure. 
These same figures were obtained by A. von Lasaulx,} in his studies on 
Silesian fluorite, and referred to the same crystalline form. Both these 
gentlemen also obtained more complicated figures, which were referred 
by them to the combination of the same figure, with a trigonal trisocta- 
hedron. 

These simple etch figures on the octahedral faces can with equal pro- 
priety be referred to the faces of a cube, since they bear the proper 
relationship to the octahedron; and to this form I refer the figures ob- 
tained on our octahedrons, for the following reasons. Although they are 
not capable of measurement, the faces look as though they stood at right 
angles to one another. Some of the larger and more isolated depressions 
possess more facets, One of these depressions is represented in Fig. 70. 
This figure, somewhat different from any obtained by Baumhauer, corre- 
sponds to the combination of a cube and dodecahedron. Now, octahe- 
drons of fluor spar are found in a great many places that need no etching 
to bring out this structure. Octahedrons are found that are entirely 
made up of little cubes, and these cubes possess at times the dodecahe- 
dral modification. Hence I think it may be inferred that there are struct- 
ural directions in these perfect, smooth octahedrons at the Notch which 
are parallel to the faces of a cube and dodecahedron, just as there are in 
those common cases, which are made so evident by the more predom- 
inating influence of the last named figures over the octahedron. 

These crystals, when heated, phosphoresce with a very beautiful violet 
light ; they also, under the influence of heat, decrepitate violently at a 
comparatively low temperature. Possibly this may be due to the fact 


* Neues Jahrbuch fiir Min, 1876, p, 605. 
| Zeitschrift fiir Krystallographie, vol. 1, p. 360. 


MINERALOGY. 37 


that they are filled with innumerable cavities containing water. Whena 
thin cleavage piece is examined under the microscope, these cavities are 
seen in immense numbers and of every conceivable form, two of the 
larger of which are represented in Fig. 7c and @. These cavities always 
contain a bubble, which is not diminished in size by heating, which 
indicates that the fluid is water. The presence of these cavities, contain- 
ing water and a certain amount of empty space represented by the bub- 
ble, is regarded as evidence that minerals containing them were formed 
at elevated temperatures and pressures, since, in minerals suitable for 
experiment, the bubbles disappear when the minerals are heated to a 
certain temperature, showing that the bubble is an empty space formed 
by the contraction of the fluid after the formation of the crystal. 

Fluor spar also occurs as a microscopic ingredient of some of our gran- 
ites and sienites, as for example, on Chocorua mountain. It is recog- 
nized in thin sections of the rocks by its very perfect octahedral cleavage, 
and by revolving the section in a horizontal plane between the crossed 
Nicol prisms, when it remains in every position uniformly dark. 


22. WaTER [H, O]. 


Some of the purest waters in the world run in the streams and come 
up in springs in New Hampshire. Pure spring waters are not common; 
but in the northern part of the state, some of the springs that come 
through the slate rocks are well-nigh pure, and a large amount of water 
when evaporated, leaves an inconsiderable residue. The spring waters 
in the Dixville Notch are most remarkably pure. The reason is, that the 
slates in these regions are composed almost exclusively of insoluble con- 
stituents. There are, however, a large number of mineral springs in 
various parts of the state, common in which are chalybeate waters. The 
springs of this kind, at Amherst, Charlestown, Pittsfield, and Unity, are 
best known. When occurring near beds of pyrites, these springs contain 
both sulphur and iron, evidently obtained from the decomposition of that 
mineral. Near Mt. Pleasant, just over the boundary in Maine, there is a 
spring of this nature. 


23. MeraconiTE [Cu O]. 


This mineral has been formed in some places by the decomposition of 


38 MINERALOGY AND LITHOLOGY. 


copper pyrites. At Orford, where the copper ores are decomposed at 
the surface, some green carbonate of copper has been formed, and also 
some black oxide. As there observed, it is an earthy, black substance, 
easily reduced on charcoal with the blow-pipe to metallic copper. It is a 
mineral of little importance to us. 


24. CorunpuM [Al], O,]. 


When this substance is impure, from the presence of oxide of iron, it 
is called emery. It is stated, in the old lists of mineral localities, that 
emery has been found at Lancaster and Lyman. The present survey 
has not detected it, and is not able to verify the statement. 


25; HEMATITE [Fe O,]. 


There are large deposits of this oxide of iron in some parts of the 
state, and in some places the effort has been made to extract it. Of the 
most mineralogical interest, the ore, as it occurs at Piermont, may be 
mentioned. There it is found in a micaceous form, made of a mass of 
the brightest scales. This ore has been analyzed by Jackson, with the 
following result: 


Tron sesquioxide, é ‘ 7 : . é ‘ . “ E 93-5 
Titanic acid, . - F f A ; . ‘ ‘ . . 3.8 
Impurities, . d 5 . . 3 < : F : : 27 

100.0 


A part of the iron ore in the beds at Bartlett and Jackson is hematite. 
Franconia, Lisbon, and Rindge are other localities; while in insignificant 
amounts it is found in many other places, and, as a microscopic ingre- 
dient, it is scattered through all our bedded rocks. 

It is most natural to find this oxide of iron so widely spread in our old 
crystalline rocks; for, as has been often shown, beds of iron ore are in 
general accumulated by the agency of water, which brings together de- 
posits of the hydrous iron sesquioxide, as can be seen in certain boggy 
places where similar deposits are being formed to-day; and, when beds 
have been subjected to such heat as we may suppose has operated in the 
crystallization of our granitic rocks, the water has been driven out, trans- 
forming them into hematite; when, at the same time, some reducing 


MINERALOGY. : 39 


agent acts upon the deposits, magnetite is produced, or sulphuretted 
hydrogen may, under the same circumstances, convert them in part into 
pyrites. These three minerals are very often associated together in 
our state. 

The presence of quite a percentage of titanium, in some of the large 
deposits of hematite, discourages the hope of their utilization. 

Hematite, as an ingredient of the rocks, is recognized by the circum- 
stance that in quite thin sections it is not opaque, but transmits light of 
a blood-red color. Sometimes in the older rocks it is seen in very mi- 
nute hexagonal scales, so thin as to be quite transparent, and of a fine 
red color. 


26. MenaccaniTE [(Fe, Ti)? O7]. 


This is a very common mineral, and in almost all the localities that 
have been given for iron ores some of it is to be found. Besides these 
places, it is found at Littleton, at Wilton in micaceous crystals on quartz, 
at Orford, and at Franconia in noticeable specimens. 

The proportion between the titanium and the iron varies greatly in 
this mineral. At times, half its weight is titanic oxide; and, again, we 
have hematites, in which only a small proportion of the iron is replaced 
by titanium. Thus, the Unity iron ore contains 6.8 per cent., and the 
Piermont ore contains 3.8 per cent. of titanic acid (Jackson). As titanium 
is such a common ingredient in our ores, any magnetite or hematite ores 
that are found in the state should be examined for titanium before any 
estimate is placed on their value or money expended in their extraction, 
since the presence of this element is very deleterious. 

Titanic iron is well-nigh universally distributed through the rocks of 
the state, almost every rock analysis that has been made showing some 
titanium. When the rocks contain magnetic iron, the analyses usu- 
ally indicate that it is somewhat titanic. The green slates, diorites, etc., 
that occupy the Connecticut valley, uniformly contain titanic iron. For 
example: the diorite at Littleton contains 7.53 per cent. of titanic acid, 
while it contains but 16 per cent. of iron, a part of which belongs to the 
hornblende ; therefore it is evident that the iron oxide is a highly titanic 
menaccanite. 


This mineral, as seen with the microscope, in thin sections of a rock 


40 ze MINERALOGY AND LITHOLOGY. 


is always opaque. It very rarely appears crystallized, but is generally 
in bits and patches of very irregular and indeterminate outline. It is 
often seen in staff-like, club-shaped, and other elongated forms, and often 
in indented and diffuse forms, which, although not sufficient to distin- 
guish it from magnetic iron, are certainly quite characteristic of titanic 
iron. When crystallized, it is hexagonal; and in some of our rocks 
hexagonal and rhomboidal plates are found which are suspected to be 
of titanic iron. 

Although menaccanite is difficult to dissolve in acids, yet it undergoes 
a peculiar kind of decomposition in the rocks, which is quite character- 
istic of it. This decomposition is very often seen in microscopic study 
of basic rocks. Its beginning is shown in grains that have a gray, trans- 
lucent edge. Then, again, this gray substance traverses the black grain 
in straight lines, following the cleavage or planes of composition; then, 
but a faint skeleton of black mineral is seen traversing the white decom- 
position product; and, finally, every trace of the titanic iron has disap- 
peared, leaving a gray, translucent mass, which by reflected light is 
white, and which possesses a structure dependent on the mode of its de- 
composition. The white product resulting has been determined by Prof. 
A. von Lasaulx to be a compound of titanic acid and lime resembling 
perofskite [Ca Ti Os]. It is supposed that the lime of the hornblende 
or feldspars reacts on the titanic iron, producing the titanate of lime; 
and sometimes, when silica also takes part in the decomposition, sphene 
may be produced. Where the iron goes to is not explained, but it 
is likely that it enters into the composition of the ferruginous chlorites, 
which are so usual in these basic rocks where this mineral is most 
common. 

The forms that the decomposition product takes, are most remark- 
able; and in our New Hampshire diorites are some more strange 
than have been seen elsewhere. When the decomposition goes on 
regularly from the circumference till it reaches the centre, the re- 
sult is a mere irregular patch of translucent material, but when it fol- 
lows the cleavage or lamination the forms are quite fantastic; and at 
times these forms possess such a very strange similarity to organisms, 
that they have deceived observers into the belief that they were the fos- 
silized remnants of microscopic forms of life that existed in the original 


MINERALOGY. 41 


sediments.* Fig. 5 on Pl. 2 represents one of the most remarkable. It 
is drawn from a section of a diorite from Connecticut lake. It appears 
in the microscope as composed of a dark gray, translucent substance 
traversed by lines of greater transparency; and nothing could resemble 
more closely the structure of a coral, or of a fragment of some rhizopod. 
By reflected light the whole appears white, traversed by faintest black 
lines. Fig. 6, though less organic in appearance, is fully as remarkable 
as a decomposition product of titanic iron. It represents a form found 
abundantly in the diorite of Hanover. Persons are naturally interested 
in finding organisms in old rocks; and besides the cautionary value that 
may be attached to these figures, they are illustrative of a method of 
decomposition, which, in our greenstones, is characteristic of the titanic 


iron. 
27. SPINEL [Mg Al, O,]. 


The mineral spinel has been found in pretty little bright red octahe- 
dral crystals in a limestone rock on Saddleback mountain. 


28. MAGNETITE [Fe; Oy]. 


This ore is found in deposits of such magnitude that efforts have 
been made to mine it. It is widely distributed in smaller amounts. At 
the Franconia iron mine, in Lisbon, there is a vein from 5 to 8 feet thick 
in the gneiss rock, which was worked for some time. Fine dodecahedral 
crystals are found there. The ore is compact, fine grained, and of a 
bluish gray color. Jackson’s analysis is as follows: 


Iron proto-sesquioxide, . é F : 3 a é ‘ d 96.20 
Titanic acid, . é é F F 5 : é ‘ : ‘i 1.50 
Silica, ‘ e . . < ‘ s : ‘i * . A 2.30 

100.00 


When the vein was worked, several other minerals in fine crystallized 
condition were obtained from the mine, and it was an often-visited local- 
ity. Garnet, epidote, and hornblende were found in crystals remarkable 
for their beauty. Magnetite occurs in large beds in Unity; but in this 


* See Hawes, American Yournal of Science, iii, vol. xii, p. 134. The other gentlemen who have seen these 
specimens, and have published opinions in reference to them, are very excusable, on the ground that they saw but 
single specimens, and are not professed experts in microscopic mineralogy. The author has paid some attention 
to the subject, under competent instruction, since the paper referred to was published, 


VOL. 1. 6 


42 MINERALOGY AND LITHOLOGY. 


ore there is a considerable percentage of titanic acid. Large amounts 
of magnetite are associated with the hematite at Bartlett. At Swanzey 
large crystalline masses are found in a granite vein. In Amherst, fine 
crystals having the planes of a cube and octahedron occur; and rhombic 
dodecahedral crystals are also found. The crystals at this place are 
sometimes two inches in diameter. At Winchester there is a large vein 
that was once worked ; it is contaminated with pyrites. Other localities 
are Berlin, Piermont, Jackson (on Thorn mountain), Lebanon, Benton, 
and Easton, besides many smaller deposits unnecessary to mention. 
There are, moreover, many localities in the state, on approaching which 
the magnetic needle is very strongly deflected; and the presence of large 
bodies of ore is suspected but not proved. 

Native lodestones are found on Gunstock mountain in Gilford. 

Magnetite is one of the most commonly occurring minerals in rocks of 
all kinds, and offers some interesting features for microscopic study. In 
almost all our rocks it is present either as an essential or an accessory 
ingredient. Even in the thinnest sections of the rocks it is perfectly 
opaque, but it is evident that, could it be made thin enough, it would be 
translucent, since in our mica quarries at Alstead it has been found in 
such thin films, between the layers of mica, as to be plainly transparent. 
These films have been shown by Prof. Brush to be magnetite.* When 
the light from below the stage is shut off, the surface of a section of 
magnetite has a bluish metallic lustre by reflected light. As a con- 
stituent of the rocks, it is often in wholly irregular grains, and, again, it 
is often in minute crystals of perfect form. In our trap rocks it is quite 
generally crystallized ; and the little crystals are often grouped together 
in various ways, sometimes forming quite complicated figures. The 
magnetite in sections of these rocks is seen in little squares or triangles, 
which are sections of octahedrons; and in more complicated right-angled 
forms, which result from the compounding of its isometric crystals. On 
Pl. 2 are represented some of the groups of crystals as seen in the rocks. 
Figs. 4 and 4@ are from a section of the diabase at Bemis brook; 44 and 
4c, from the same rock at the Lincoln Flume; and 4d is a more delicate 
form, which is drawn from a section of the porphyritic diabase of Con- 


* See Dana’s Mineralogy, p. 150. 
+ See Pl. iii, in Zrkel’s Basaltgesteine. 


MINERALOGY. 43 


cord, Vt. All these forms are, however, quite common, and are often 
observed in the trap rocks. The delicate arborescent forms like the last 
appear, with high magnifying power, to be composed of crystals; but the 
form of the crystals is disguised by the presence of myriads of minute 
translucent crystals that have attached themselves to them. 

These skeletons of magnetite, so regularly formed, indicate that the 
magnetite was the first mineral to form in these rocks, since such delicate 
yet determinate forms could only develop in a quite plastic mass. Some- 
times hexagonal sections are found, which may be sections of dodecahe- 
drons ; but in such cases it is not easy to decide whether it is magnetite 
or titanic iron. It may be stated, however, that magnetite is more often 
crystallized than titanic iron, and is usually easy to recognize by its form ; 
and when without definite form it is more often in compact grains, and 
does not show the peculiar decomposition to which titanic iron is subject. 

At times, particles of magnetite are grouped in regular forms not de- 
pendent on its own crystallization, but on that of some other mineral. 
For example: in sections of some of our diorites we see that the horn- 
blende has been well-nigh entirely decomposed, and though possessing 
still its original form, it is now composed of an aggregate of three or four 
other minerals, among which magnetite is at times predominant. When 
magnetite has thus resulted from the decomposition of a ferruginous min- 
eral, like hornblende, the individual particles are often grouped together in 
forms resulting from the outline or the cleavage of the hornblende. Fig. 
3 on Pl. 2 is drawn from a section of the eruptive diorite from near the 
Profile house. This section is cut parallel to the base of the original 
hornblende crystal; and the magnetite is arranged along lines parallel 
to its cleavage. In other crystals the magnetite surrounds the edge, in 
a regular line, and is irregularly scattered through the interior. Some- 
times, again, a row of magnetite grains surrounds the outside boundary 
of an apparently intact crystal. The figure given is, however, sufficient 
to illustrate this subject. A high magnifying power does not show that 
these particles are crystalline. 

Magnetic iron decomposes with difficulty; but its grains in rocks are 
often seen surrounded by a yellow ring of the hydrous sesquioxide of 
iron. 


The beds of magnetite, such as exist in our state, are supposed to result 


44 MINERALOGY AND LITHOLOGY, 


from the combined action of heat, resulting from metamorphic action, 
and some reducing agent. This action has converted beds of hydrous 
iron sesquioxide, which were accumulated by the action of water, into the 
magnetic oxide. 


29. CHROMITE [Fe Cr, O,]. 


Chromic iron has been found in several places in Vermont. In New 
Hampshire, a small amount has been found in the soil of Dublin. It is 
most often found associated with serpentine rocks, of which we have 
none that is readily accessible. 


30. CurysoBeryL [Be Al, O,]. 


This rare mineral has been found in a narrow vein, which was opened 
in making the deep cut through the granite rocks at Orange summit.* 
The form of the crystals was compound, like that of the crystals from 
Haddam in Connecticut, which are well known; but none were found 
with terminal planes to the crystals, and all were more or less imperfect. 


31. CassIrERITE [Sn OJ]. 


Dr. Jackson, thinking that circumstances were favorable for the discov- 
ery of tin mines, made a most careful search for this mineral in our state, 
and at last succeeded in finding it; since which discovery much time and 
money have been expended in the hope of turning the discovery to prac- 
tical advantage, but thus far with no success. 

It was first discovered in 1841, in the town of Jackson. It occurs in 
little veins at the junction of a dyke with the schistose rocks. Large 
excavations have been made with the idea in view of extracting the ore, 
but no quantities sufficient to yield metal of consequence were met with. 
This was the first discovery of tin ore in the United States. 

Cassiterite, as found at Jackson, is sometimes crystalline and sometimes 
massive. Fig. 6 on Pl. 3 represents one of the crystals. The figure was 
drawn by Mr. J. E. Teschemacher for Dr. Jackson. It is a twin crystal, 
the twinning plane being parallel to the plane of a pyramid of the second 
order. It is much enlarged, for the best crystals are very small. I have 
seen no perfect crystals from there; but those that I have found appear 


* Prof. O, P. Hubbard, American Yournal of Science, ii, vol. xi, p. 424. 


MINERALOGY. 45 


to be twins, like the one figured. The cassiterite at Jackson is dark col- 
ored and opaque, except in the thinnest fragments. The veins are from 
half an inch to several inches wide, but they are mostly filled with arsen- 
opyrite, chalcopyrite, and other minerals. The veins are in mica schist. 
Tinstone has also been found in the town of Lyme, but in much smaller 


amount than at Jackson. 
32. Rutite [Ti O,]. 


Rutile has been found at several places in our state. A red, massive 
variety occurs at Merrimack, on the Souhegan stream; and a considera- 
ble amount has there been extracted for economic purposes. Crystals 
have been obtained from the soapstone quarries at Richmond, where 
many other interesting minerals have been observed. In the rocks ac- 
companying the limestone at Orford, crystals have been found; also, at 
the same place, quartz crystals are obtained, which contain acicular crys- 
tals of rutile. Such quartz crystals were first found in Orford by Dr. 
Horsford ; but masses and crystals of quartz, penetrated through and 
through by delicate rutile crystals, have been found at several localities. 
Handsome specimens have been found near Hanover and at Cornish. In 
the last named place, a large, smooth, round pebble of quartz, as large as 
a man’s head and filled with little needles of rutile, was found a long 
time ago, and was broken up and distributed among mineralogists. 
Rounded pebbles of quartz, with needles of rutile, have been found in 
the river-bed at Lebanon. These loose pieces may all have been brought 
from Orford, which lies to the north. The little crystals penetrating the 
quartz vary from a delicate straw color, when very small, to jet black 
when larger. Some of the finer specimens are cut as jewels. Lyme, 
Merrimack, Richmond, and Warren are other localities for rutile. 

The microscope reveals the presence of rutile as a frequent constituent 
of our granites and schists. It is most often seen in very minute needles 
piercing the quartz, thus forming microscopic specimens of the same na- 
ture as the macroscopic ones. These needles are often very long; and 
frequently those that appear short will, on changing the focus of the 
instrument a trifle, be found to go on to surprising lengths. -They are 
often straight and often curved, and almost always in clear quartz. Some- 
times, with the hand on the thumb-screw, in order to be able to focus 


46 MINERALOGY AND LITHOLOGY. 


deeper into the specimen, a needle can be followed in its curving course 
through a distance two or three times the width of the field. 

The most interesting microscopic occurrence that I have observed is 
in the actinolite schist of Pittsburg. The rock is a compound of actino- 
lite and quartz, in which the quartz is penetrated by the delicate black 
needles, to which I have already referred, while the actinolite contains 
much larger and more perfect yellowish-red crystals of rutile, which show 
very well the tetragonal, crystalline form of the species. The crystals 
are apparently eight-sided; and some of them possess the geniculations 
so characteristic of the species. The crystals lie scattered about indefi- 
nitely in the actinolite ; and, as all the large crystals are in that mineral, 
it may be assumed that the circumstances for the formation of crystals 
of rutile were more favorable in that mineral, or at the time that it was 
made, than in the case of the quartz. Fig. 1 on Pl. 4 represents a much 
magnified section of this rock, in which the condition of the rutile, both 
in the actinolite and in the quartz, is shown. 


33. PyrotusiTE [Mn O,]. 


This ore of manganese is found at Winchester and Hinsdale, associ- 
ated with the manganese silicate that occurs there. At Northwood, 
tuberous and mammillary specimens have been found in the granite. It 
is not an abundant mineral, but as a black incrustation, soiling the fin- 
gers when touched, it is quite widely distributed. It is not found crys- 
tallized in the state. 


34. Limonire [H, Fe, Og]. 


Under this head, besides the pure mineral, the deposits of bog ore 
will be noticed. In several places these bog ores have been extracted 
for reduction; and it is reported that excellent iron has been made from 
them. In Lancaster, bog iron ore was found constituting the hardpan of 
a meadow, and was easily extracted. In Bedford, Amherst, and Merri- 
mack are deposits that have been worked. In Bath, a swamp deposit 
was found beneath three feet of mud, and was easily broken up and 
drawn out. In Madison, Dr. Jackson discovered a deposit in the bottom 
of Six-mile pond. It is found in the low lands of Grafton and Lebanon, 


MINERALOGY. 47 


where it has been deposited by sluggish streams. On Black mountain 
in Haverhill there is a deposit of the compact botryoidal limonite. Bar- 
rington, Gilmanton, Kingston, Mason, Lyndeborough, New Boston, Ches- 
terfield, Nottingham, West River mountain, Orange, Pembroke, Salisbury, 
Jaffrey, Moultonborough, Orford, Surry, and Plainfield are other towns 
where deposits of the hydrous iron oxide are found. As may be inferred, 
it is generally distributed all over the state, either as the compact, dark 
mineral limonite, or forming ochrey beds of a foot or more in thickness, 
and again, as a mere ferruginous deposit in the gravel, where it cements 
the pebbles together. 

The mode of origin of limonite has been treated of by many writers. 
The beds in this section of the country were shown by Percival* to have 
resulted from the transportation and redeposition of the iron from decay- 
ing pyritiferous rocks. Other writers have followed, showing the same 
to be true of the other deposits that occur along the Atlantic coast. The 
exact source of the iron can generally be ascertained by studying the 
rocks of the region. The method of transportation has also received 
much attention; for, as the sesquioxide of iron is insoluble, if it were 
transported in solution it must have been in some other condition- 
There are many chalybeate springs in our state, several of which are 
found near by the deposits of bog iron, and which show that here as 
elsewhere the iron has in part been transported in the state of carbonate. 
Sometimes by oxidation pyrites is converted into a sulphate of iron, and 
thus transported, and, again, it is transported as a salt of an organic acid, 
as suggested by Berzelius, and verified for our ores by Jackson, + who 
analyzed these ores, and found varying amounts of organic acids in them. 
Hunt, in the ochre of Pointe du Lac in Canada, found fifteen per cent. of 
humic acid; and Jackson’s analyses show varying amounts from none to 
eighteen per cent. of vegetable matter, which he refers to organic acids; 
but what proportion of this resulted from the vegetation of the swamps 
in which the ores were deposited is not with certainty determined. Iron 
transported in any of these ways is liable to be deposited as the hydrous 
sesquioxide, as soon as it is subjected to oxidation, though a portion of it 
may remain as carbonate; and more or less of the carbonate of iron 


* Rep. Geol. Conn., p. 132. 
+ Geology of New Hampshire, Dr. C. T. Jackson, 1844 


48 MINERALOGY AND LITHOLOGY. 


exists in most of the bog ores of iron, as is proved by treating them with 
hydrochloric acid. In some of our bogs this ore can be seen in process 
of formation. A sluggish stream, flowing perhaps from a chalybeate 
spring, runs into a marshy spot, and the top of the water is seen covered 
with an iridescent slime,—a result of the oxidation of the iron in solution 
to the insoluble sesquioxide,—while the bottom is covered with a yellow 
deposit of sesquioxide of iron. 

Limonite is a common constituent of rocks. Sometimes it exists as 
an original constituent, as where it forms the cementing material of con- 
glomerates; or, again, it results from the hydration of other oxides of 
iron, under which circumstances it appears as a yellow, semi-transparent 
substance surrounding an opaque, unaltered core, if the decomposition 
is incomplete. 

I would refer to a number of analyses of hydrous iron ores in Jack- 
son’s report; but, as they have no mineralogical significance, they are 


not reproduced here. 
35. PSILOMELANE, Wap. 


Impure, hydrous manganese oxides. Wad is found in many of the 
deposits of bog iron ore. Sometimes it is sufficiently compact and pure 
to be called psilomelane, but most of it is very impure, being much con- 
taminated with iron oxides, organic matter, and other impurities. It is 
recognized as a manganese oxide by its black color, and its manganese 
reactions before the blow-pipe. Psilomelane is fonnd at Winchester, 
with the other manganese minerals. 


36. Motyzspire [Mo 03]. 


This mineral is a result of the oxidation of the sulphuret of molyb- 
denum or molybdenite, and occurs in connection with it. It is found in 
the cavities of the veins of molybdenite in Westmoreland in considera- 
ble amount, and less abundantly with the other deposits in Landaff and 
Franconia. As it occurs in our state, it is an earthy, yellow mineral, 
filling cavities or incrusting the sulphuret. 

This mineral is easily recognized by heating it with the blow-pipe upon 
a piece of charcoal, when it is volatilized, coating the coal with a white 
sublimate, which, when touched for an instant with the reducing flame, 
is changed to a beautiful blue color. 


MINERALOGY. 49 


The molybdite of Westmoreland contains six tenths of one per cent. 
of oxide of uranium,* which makes the mineral from this locality remark- 
able, and which gives to it a deeper yellow color than is common in spec- 


imens of molybdite. 
37. QuARTZ [Si O,]. 


This mineral, which forms the larger part of the crust of the earth, 
is of particular importance in those parts of it that are occupied by 
old crystalline rocks like New Hampshire. 

Common transparent, glassy quartz forms a large proportion of our 
rocks, and is, moreover, found in the most grand and beautiful crystalli- 
zations. On Moose mountain some very fine and large crystal masses 
have been found. A group of these crystals in the Dartmouth College 
cabinet weighs 147% pounds. It contains forty-eight crystals, four of 
which are from five to five and a half inches in diameter. Fine, large, 
clear crystals are also found at Benton, Littleton, Bartlett, Hanover, War- 
ren, Westmoreland, the White Mountain Notch, and Raymond. 

The crystals in some localities have a smoky tint. Smoky quartz is 
found at Bartlett, Cornish, and the Notch. The Cornish specimens are 
penetrated with rutile; and the presence of-titanic acid is supposed by 
some to impart the smoky color to this variety of quartz. 

Quartz of a delicate rose color, called rose quartz, occurs in mica 
schist rocks in the White Mountains, at Acworth, Raymond, Andover 
(on Ragged mountain), and Keene. It is quite abundant on Mt. Wash- 
ington; and much of it is annually carried away by tourists. 

Amethyst or purple quartz is found at Surry, Mt. Crawford, Waterville, 
and Westmoreland,—at the latter place in fine crystals. Moreover, some 
fine, large crystals have been ploughed out of the soil in Amherst. Some 
of these were three inches in diameter and eight inches long. Fine, 
rolled pieces are found at Hampton Falls. Quartz with a purplish tint 
is common. 

Among other occurrences of note may be mentioned beautiful green 
crystals, colored by epidote, at Franconia and Enfield; fine red and yel- 
low crystals, colored by oxide of iron, at Francestown, Gilmanton, and 


%* Jackson. Geology of New Hampshire, p. 230. 
VOL. IV.. 7 


50 MINERALOGY AND LITHOLOGY. 


Hanover; jasper, also, at the same places; quartz, penetrated through 
and through with tourmaline needles, at Sullivan and on Moose moun- 
tain, besides numberless occurrences of local interest. 

The white translucent variety of quartz is found in large beds at Al- 
stead, Hancock, Bedford, Amherst, and Lyndeborough ; and Prof. Hitch- 
cock has traced a system of veins of it which extend for more than fifty 
miles through the gneissoid rocks. At times, a kind of quartz filled with 
cavities, making what is called buhrstone, is found in veins. This kind 
of quartz occurs at Littleton. 

At Grafton a very large, interesting crystal has been found, which is 
in the collection of the survey. It consists of a huge crystal a foot long 
and eight inches in diameter, but which is entirely made of little crystals 
with their planes all parallel to the planes of the large crystal. This 
complex form of a quartz crystal is not uncommon, but such large, fine 
specimens are rarely seen. 

The. microscopic characters of quartz are so fully illustrated in the 
lithological part of this report as to need little explanation here. It may 
be briefly stated, however, that basal sections of quartz differ from other 
hexagonal minerals, in that a beam of light passing through them par- 
allel to the vertical axis is rotated to a certain degree; and hence quartz 
between crossed Nicols exhibits the phenomenon of circular polariza- 
tion. The amount of rotation of the light depends upon the thickness 
of the plate; and also the different colors of the spectrum are rotated to 
a different degree. Hence, if a plate of quartz thus cut, and of some 
thickness, is inserted between crossed Nicol prisms, the plate will not be 
dark, as in the case of ordinary hexagonal minerals; and neither will the 
plate be dark, whatever be the position of the Nicols with reference to 
one another; but as the upper Nicol prism is revolved it will meet the 
different colors of the spectrum in succession, and the amount that it 
must be turned to intercept all the colors from red to violet will depend 
on the thickness of the plate; and whether the polarizer must be turned 
to the right or the left, in order to intercept the colors in the order of 
their arrangement, beginning at the red end of the spectrum and pro- 
ceeding towards the violet, determines whether the crystal is right- or 
left-handed. If, now, the section of quartz be cut very thin, it is plain 
that the revolution of the light may be so small as to be imperceptible, 


€ 


MINERALOGY. 51 


and then, between crossed Nicolls, it will not show colors, but will approach 
towards the behavior of other hexagonal minerals. If the section be a 
little thicker,—of the thickness of ordinary rock sections,—the light will 
not be rotated to such a degree as to separate the prismatic colors so 
widely from one another as that one can see that the mineral exercises 
circular polarization; but still the section will not be entirely dark be- 
tween crossed Nicols, and will not become so on rotating it in its plane. 
Sections cut at all varying from the basal plane polarize the light, giving 
the most brilliant interference colors. 

It may therefore be said that, in microscopic sections of rocks that are 
of the proper thinness, quartz, although optically peculiar, does not differ 
essentially from ordinary hexagonal minerals, and that its colors in polar- 
ized light are peculiarly brilliant. Other microscopic characters are the 
uniformity of these interference colors over its whole surface, except at 
the edge of its crystals or grains. The edges are differently colored, on 
account of the varying thickness at these points. The almost uniform 
presence in it of little cavities filled with fluid, and containing bubbles 
and often little crystals, is noticeable. These cavities are often hex- 
agonal. Figures of them will be found in the plates. 

As quartz was, as a rule, the last mineral to crystallize in our rocks, it 
is more often in rounded or irregular grains than almost any other min- 
eral. As it is very difficult to decompose, it is ordinarily clear and trans- 
parent in thin sections, while the minerals that surround it are more or 
less decomposed. It possesses no cleavage, and when in large particles 
is usually traversed by irregular fractures. In a fine-grained mixture of 
quartz and orthoclase, the two minerals are not easily distinguished from. 
one another, as they both give brilliant colors in polarized light, and the 
cleavage and other properties of the feldspar cannot be recognized. In 
such cases, in examining sections of our old rocks, the presence of the 
two minerals together is best recognized in the microscope by shutting 
off the light from below, and examining by reflected light, when the 
quartz, which is clear and undecomposed, appears black, while the feld- 
spar usually appears as a white, opaque, snowy. substance, this effect 
being produced by its impurities, minute fissures, and partial decomposi- 
tion. 


52 MINERALOGY AND LITHOLOGY, 


38. OPAL. 


An amorphous and usually hydrous form of silica. 

This substance exists in large quantities in New Hampshire, in the 
condition of infusorial earth, or mountain meal, as it is often called. In 
trade it is called tripolite. The deposits of this substance are large, 
especially in the northern part of the state; and it is in that condition 
of purity that makes it the best polishing powder. The following is my 
analysis of a specimen from Lake Umbagog: 


Silica, . : F : : : : A a a ‘ ‘i 80.53 
Alumina, ‘i . z ‘ . . , c a . ‘ 5.89 
Iron sesquioxide, . : é é ‘ z - zi : F 1.03 
Lime, % : : - ‘i F ‘ e “ . . ‘ +35 
Water, . e : . , ‘ ‘ 5 - ‘ é ‘ II.05 
Organic matters, . : a: . . : . F 7 . -98 

99-83 


The analysis indicates that this substance is essentially hydrated 
silica. It is found forming layers in the muddy bottoms of ponds, and 
in bogs as a sub-peat deposit, and often it exists in such a state of purity 
as to be white and soft when dry, and thus it often attracts attention. 

These infusorial earths were first investigated by the Count Ehren- 
berg, and he found them to be nearly entirely made up of the siliceous 
remains of diatoms and infusorial animalcule, which, although of such 
minute size, possessed forms of great beauty. From a large bed of this 
earth near Richmond, Va., over one hundred species of these microscopic 
organisms have been obtained and described by Ehrenberg and Bailey. 
The New Hampshire deposits are, however, all fresh water deposits, and, 
in common with such deposits all over New England, they are entirely 
composed of diatoms, and contain no foraminiferal forms. Specimens 
from our state have been investigated by nearly every one who has inter- 
ested himself in the study of infusoria, but no better idea can anywhere be 
obtained of the appearance of these deposits under the microscope, and 
of their average composition, than by an examination of the figure which 
was drawn long ago by Ehrenberg, from a specimen of such an earth from 
our state. His work is not now easily accessible, and therefore I repro- 
duce the figure here. Fig. 6, on Pl. 4, represents the field of Ehrenberg’s 


MINERALOGY. - 53 


microscope, as it appeared occupied with a sample of New Hampshire 
infusorial earth.* The species represented are as follows : 


Polygastern. Fig. 17. Himantidium arcus. 
Fig. 1. Chaetophila Saxipara. 18. ee gracile. 
1" , Discoplea Coscinodiscus. ge Navicule a oxy: 
2s zo. ‘  dilitata. 
3. Eunotia icosodon. 21.  “  Jineolata. 
4. “© monodon. 2z. ‘  Legumen. 
5 “*  octonaria. 23. Pinnularia Semen. 
6. «¢  quatuordenaria. 24. “ viridis. 
7 ‘« septenaria. 25. Stauroneis Phcenicenteron. 
Oo 20: { Tabellaria trinodis 
9 ‘*  tredenaria. 27. : 
Io. ‘*  triodon. 28. Trachelomonas? levis. 
Il. a & 29. a pyrum. 
12. ‘¢  undenaria. Phytolitharien. 
13. Fragilaria constricta. 30. Lithodontium furcatum. 
14. Gallionella distans. 31. Spongolithis aspera. 
15. Gomphonema gracile. Soft parts of Plants. 
16. “ truncatum. 32. Pollen Pini. 


These organisms are excessively minute, and a cubic inch of this earth 
contains many millions of individuals. 

Dr. A. M. Edwards has studied these earths, and in Vol. I of this geo- 
logical report will be found a lengthy treatise on the diatomaceze in 
general, with illustrative plates.} The small figures here reproduced 
are sufficient, however, to show those interested in the subject from a 
mineralogical stand-point, the nature and composition of these interesting 
deposits. 

This substance is also of considerable economic value. It is burned 
till it is white, whereby the water and organic matters are removed, and 
it then constitutes the best kind of polishing powder ; for, although they 
are quite hard, the grains are so extremely minute that they scarcely 
feel gritty between the teeth, and consequently the substance is emi- 


Aw ela’ + . : 
maison lee lena Sa Set aes ieee, Shae earth te soluble in caustic 


X. Also, Monatsbericht der Berliner Akad. der Wissenschaften, 
cz 


t Mr. H. L. Smith, of Geneva, N. Y., has also examined these earths, 


s : and is prepared to furni F 
series, embracing all the different species, properly mounted for microscopi Prep rnish a typical 


ic study, 


54 MINERALOGY AND LITHOLOGY. 


potash or soda, making a silicate, which is called soluble glass. This 
substance is a valuable cement. Wood, when coated with it, is fire- 
proof; and eggs, after being dipped in it, will remain fresh. It is, be- 
side, a great purifying agent, and nothing else put in the water will 
give that pure whiteness to linen that can be obtained by the use 
of this substance. There are many deposits in this state, which are too 
small to be of commercial value, but which might be much more gener- 
ally utilized by the people of the neighborhood. The substance has 
been latterly employed as the basis of dynamite.* It is a bad conductor 
of heat, and serves as a good protection for boilers and steam-pipes. 
A detailed list of localities for this substance in this state is given in the 
report above alluded to, by Dr. Edwards. 

These deposits are still being accumulated. If the material at the 
bottom of any stagnant pool of long standing is carefully examined with 
the aid of the microscope, these minute plants will be found in immense 
numbers. 

Dr. Jackson obtained seven and one half per cent. of phosphates of 
lime and magnesia from a specimen from Hooksett.{ Any such material 
would make an excellent fertilizer for fields near at hand. I have myself 
seen no such phosphatic infusorial earth, and attribute the presence of 
such an amount as indicated by Dr. Jackson’s analysis to some acci- 
dental cause. i 

39. HyprersTHENE [(Mg, Fe) Si O,]. 


This mineral is distinguished from other minerals related in compo- 
sition to pyroxene by its orthorhombic crystallization. It occurs in the 
gabbro of Waterville. It is a constituent not often visible to the naked 
eye, but is easily recognized by its optical properties observable in micro- 
scopic sections, and by the: circumstance that it possesses the same 
peculiar interpositions that make it so noticeable elsewhere. 

The most remarkable occurrences of hypersthene in America are at 
St. Paul’s. island, Labrador, and at one or two points in Canada. As 
there observed, it has a deep brown color, and easy cleavage parallel to 
the brachypinnacoid, and. the microscopic sections show that, inlaid in 


* See Ann. Rep., G. H. Cook, State Geologist of N. J., 1874. 
+ Geology of New Hampshire. Hitchcock. Vol. I, p. 502. 
t Geology of New Hampshire. Jackson, p. 185. 


MINERALOGY. 55 


planes parallel to this plane, are immense numbers of little brown scales 
or rhombic plates. The true nature of these scales has not been deter- 
mined, but they have been suspected to be brookite by some—a conclu- 
sion doubted by others. It is only known that they impart the metallic 
copper color to hypersthene, and that they are inlaid in the determined 
plane in three directions, one of which is nearly parallel to the vertical 
axis, one at right angles to it, and one making an angle of about 30° 
with it. 

Turning now to our hypersthene, it may be noticed that in thin sec- 
tions it is much lighter in color than that occurring elsewhere, and, indeed, 
it is nearly colorless in thin sections. It occurs in irregular fragments 
and grains in the rock, giving no sign of external crystal faces; but when 
in a microscopic examination of a thin section, the vertical axis, as indi- 
cated by the cleavage, is brought parallel to the plane of vibration of 
either one of the crossed Nicol prisms, the section is dark, and does not 
disturb the interference figure of a calcite plate put on the ocular under 
the upper Nicol prism. Hence, it is orthorhombic. The interpositions 
are like those in the St. Paul’s Island hypersthene. It contains magne- 
tite in irregular fragments irregularly distributed, and brown scales much 
darker in color, however, than those in most hypersthene, and which are 
symmetrically arranged. The larger part are nearly parallel to the ver- 
tical axis, but not exactly, for, as was observed by Kosman, the plane of 
the interpositions builds an angle of 7° 45’ with the cleavage plane. 
The second part are inlaid, with their long edges making an angle of 
about 30° with the cleavage lines, and a few scales are apparently inlaid 
at right angles to the first. A peculiarity of this hypersthene is the 
large number of interpositions making the oblique angle to the vertical 
axis. Fig. 2,on Pl. 4, represents the appearance of the hypersthene in 
the Waterville rock, and the mode of arrangement of its characteristic 
interposition. It is not abundant, but it is very conspicuous in some 
sections of the rock, and is very easily distinguished from the pyroxene, 
olivine, etc., with which it is associated. 


40. Prroxene [R Si O,]. 


R standing for Ca, Mg, Fe, or Mn. 
Pyroxene is found at some localities in fine large crystals, and it is 


56 MINERALOGY AND LITHOLOGY. 


also a prominent ingredient in some of our most interesting rocks. In 
the town of Amherst, fine and much sought specimens, containing pyr- 
oxene, vesuvianite, and cinnamon garnets, associated together, are found 
in the limestone. Fine crystals are also found at Warren; and at Haver- 
hill there is a locality where beautiful green crystals of pyroxene are 
found associated, as at Amherst, with cinnamon garnets. 

Pyroxene is one of the most important minerals that plays a part as a 
rock constituent. It is most common in basic rocks, though it also en- 
ters at times as an essential into the more acidic rocks, as, for example, 
the augite sienites. Hence, the study of the mineral as a rock ingredient 
is most important in our state; and its constant recurrence in various 
forms renders this study interesting. 

In our rocks, augite occurs both in crystals and grains. When 
of sufficient size to be macroscopically examined, it is either black or 
dark in color, and the cleavage surfaces that it shows are at right angles 
to one another, so that it is without great difficulty distinguished from 
hornblende ; and when it sinks to smaller proportions, the microscope 
determines it with certainty. At times it is well crystallized in the 
rocks, as, for example, in the olivine diabase of Campton Falls. The 
outlines that are obtained in cutting a section of a rock where the augite 
is crystalline are such as would be obtained by cutting a crystal 
of the most ordinary and common form, for the rare and complicated 
forms that are found on free crystals do not occur on ingrown crystals. 
Fig. 3, on Pl. 4, is drawn from a section of the Campton Falls rock as 
an illustration, and a common augite crystal is introduced into the 
figure for comparison. It is seen that sections parallel to the base 
(section a) willbe eight-sided, those parallel to the orthopinnacoid (6) 
will be six-sided, while those parallel to the clinopinnacoid (c) will be 
four-sided, and modified and distorted figures will be obtained in oblique 
directions, but which can usually be identified. The cleavage is parallel 
to the faces of the prism 7; hence the basal sections show a right- 
angled cleavage, which is sometimes nearly perfect, as in this case, but 
more often it is interrupted, though it can almost always be recognized. 
The mineral being monoclinic, those sections that contain the ortho- 
diagonal (sections 4 and a) will be dark between crossed Nicols, when — 
a side of the prism is parallel to the plane of vibration of the light, while 


MINERALOGY. 57 


all other sections will show a variation from this deportment, and if a 
clinodiagonal section (c) is examined it will be found that if the vertical 
axis is placed parallel to the plane of a Nicol prism, the section must be 
revolved 39° (or the complement of this angle in the other direction) in 
order to reach the point where the section will be dark between crossed 
Nicols, and not distort a calcite interference cross; thus showing that 
an elasticity axis makes this angle with the vertical crystallographic 
axis. 

Augite is more often in grains, showing no crystalline faces, and then 
its cleavage serves to distinguish it from other minerals with which it is 
liable to be confounded; and it is to be noted that the mineral is not 
markedly dichroic, and hence when revolved with simply the polarizer on 
the microscope, no marked variation in color is seen, as it comes into 
different positions with reference to the light; but when revolved be- 
tween crossed Nicols, the interference colors that are obtained. are very 
brilliant. 

Pyroxene is sometimes foliated, the laminz being parallel to the ortho- 
pinnacoid. Pyroxene of this structure characterizes the rock gabbro. 

The alterations that augite undergoes, as developed by microscopic 
study, are quite interesting. The most evident one in our rocks is the 
alteration of augite into hornblende, of which examples are common. This 
change is merely a molecular one, since the two minerals have the same 
composition ; but it becomes very evident by the alteration of cleavage, 
and all other physical characters. Sometimes the change is complete, 
giving us hornblende in augitic forms; and sometimes it is partial, when 
we have hornblende with a core of augite. This change was first noted 
by Gustav Rose, who named the hornblendic product uralite, and the 
rocks containing it uralite porphyry, &c. The resulting uralite has 
usually a fibrous structure. I have never seen so pretty an illustration 
of this kind of change as is furnished by the augite sienite of Jackson, 
in our state. Here the augite is not altered into a fibrous green uralitic 
mass, but into fine, compact brown hornblende, which contains, as a rule, 
a core of augite. The cleavages of the two minerals also bear a definite 
relationship to one another. If we lay out the lateral axes of a crystal of 
augite (see Pl. 7, Fig. 1) and connect their ends, we shall havea nearly 


square figure, which is the base of the prism of augite, and the sides of 
VOL. Iv. 8 


58 MINERALOGY AND LITHOLOGY. 


which are parallel to the ordinary cleavages of that mineral. If, now, we 
double the length of the orthodiagonal, and connect the ends with the 
ends of the same clinodiagonal, we obtain the base of the hornblende 
prism to the sides of which the ordinary cleavage of hornblende is par- 
allel. Now, in these altering grains of augite in this sienite from Jack- 
son, the cleavages of these two minerals bear the ‘exact relationship to 
one another that these two figures do when thus constructed, as is shown 
in Pl. 7, Fig.1. This is a basal section, and the cleavage of the outside 
hornblende is seen to be parallel to the outside figure of the accompany- 
ing diagram, while the inside augite exhibits a cleavage parallel to the 
inner part of the little diagram. The hornblende is strongly dichroic, 
as is shown by the yellow bit above, which is cut parallel to the prism, 
while the augite is not dichroic. This case of alteration furnishes a most 
instructive illustration of the relationship that exists between these two 
minerals, 

Another kind of change has been effected by that slow weathering 
that has converted the pyroxene into a green hydrous mineral. Pyrox- 
ene is very subject to this kind of alteration. This green product is 
known to be a kind of chlorite, and viridite is a name that has been pro- 
posed for it when its nature is unknown. This is a convenient word to 
apply to the green unknown results of decomposition ; but several persons 
have attempted to determine the nature of this viridite, which plays SO 
important a role in basic rocks, and Dr. K. L. Th. Liebe determined it 
to be a kind of chlorite, with the composition of an unisilicate, a con- 
clusion confirmed by an analysis made by myself on pure material gath- 
ered from diabase. Now, the change from the calcareous bisilicate 
pyroxene to the magnesian unisilicate chlorite involves the separation 
of a definite amount of lime and silica, and hence, as a rule where this 
decomposition has taken place, we find lime carbonate and silica as asso- 
ciations of the green chlorite. Other kinds of decomposition take place, 
resulting in the production of epidote and various hydrous silicates; and 
sometimes augite crystals are decomposed into a heterogeneous mixture 
with the mere outline preserved. 


41. RuHoponiTE [Mn Si O3]. 


Rhodonite is abundant in some localities in the south-western part of - 


MINERALOGY. 59 


the state. It forms beds in the gneissoid rocks. It is found sometimes 
of the rose color characteristic of the pure, unaltered mineral, but usually 
of various shades of brown, the color being dependent upon the degree 
of oxidation or decomposition. A bed of it is situated on the top of 
Stony mountain near Winchester, and another on a hill a mile south-east 
of Hinsdale. The latter bed is seven feet thick, and quite extensive. 
Smaller deposits are found at other points in these same neighborhoods. 

This mineral is subject to easy alteration, for the lower oxide of man- 
ganese is unstable, and has a constant tendency to oxidation. This 
change results in the production of a brown or black silicate of man- 
ganese sesquioxide, which is called marceline. On the exterior of the 
mineral the silica is sometimes removed, leaving a coating of manganese 
oxide, or pyrolusite, and when water containing carbonic acid acts upon 
the mineral, a carbonate of manganese is formed which is rhodochrosite. 
Products resulting from one or all of these methods of decomposition are 
common at the localities mentioned, as at all other localities of this ore. 
Such products have been often analyzed, and names have been given to 
them, but the decomposition is not usually so complete as to produce 
a perfectly homogeneous product, and hence they are usually mixtures 
of minerals. 

The following is an analysis, by Dr. Jackson, of this mineral from 
Winchester : 


Silica, ‘ ‘ a 5 e : ‘ . * : ‘ : 26.4 
Tron oxide, ‘ 5 ‘i C : - : 7 ‘ « ‘ 4. 
Manganese oxide, . . 7 F F : F F ‘ : 68. 
Loss, . i . : . < ‘ é % é 7 1.6 
100.0 


Pure rhodonite is composed of 45.9 of silica, and 54.1 of manganese pro- 
toxide. Comparing this with Jackson’s analysis, we see that he analyzed 
a decomposition product. His analysis is just like many others that have 
been made upon such products, and proves it to be the variety marceline, 
in which the manganese exists for the most part in the state of sesqui- 
oxide. 

Rhodonite, when crystallized, is isomorphous with pyroxene; but our 
mineral is massive. It fuses easily, and imparts a deep violet color to a 
borax bead, the color becoming red-brown when the bead is cold. 


e 
60 MINERALOGY AND LITHOLOGY. 


42. SPODUMENE [3 Li? Si O?-1.4 AP Si O°}. 


This is another silicate isomorphous with pyroxene. It is found in 
good crystals at Winchester. Its crystals are white in color, and usually 
flattened by the wide development of the orthopinnacoid. The ingredi- 
ent that characterizes this mineral is its lithia. The crystals resemble 
those from Huntington, Mass., which Prof. Brush found to contain more 
than five per cent. of that oxide. The mineral is easily recognized by 
its large, tabular crystals, its easy cleavage parallel to the orthopinnacoid, 
and the carmine color that it imparts to the blow-pipe flame. 


43. ANTHOPHYLLITE [(Mg, Fe) Si O,]. 


This mineral occurs in a talcose rock at Richmond. It is character- 
ized by its fibrous structure, its brown color, and its infusibility before 
the blow-pipe. It is the orthorhombic species of the hornblende group, 
and hence may be distinguished in a thin section by the circumstance 
that it is dark between crossed Nicol prisms when its fibres are parallel 
to the plane of vibration of the light; but it has no significance in our 
petrography, although Brooks has found it as a common constituent of 
rocks about Lake Superior, which occur in formations lithologically 
related to some of ours. 


44. AMPHIBOLE [R Si O,]. 


R standing usually for Ca Mg and Fe. It also often contains alumina 
and alkali. . 

Amphibole here, as elsewhere, is one of the commonest minerals. 
Fine crystalline specimens are found. It is a very common ingredient 
of the rocks, and forms rock masses by itself. 

The common dark colored variety, which is usually called hornblende, 
has been found abundantly in superb crystals at the Franconia mines in 
Lisbon. Long-bladed crystals are also found there, and at Warren. 
Hornblende is found in fine crystals at Exeter, Hanover, Winnipiseogee 
lake (on Red hill), and Moultonborough. 

Actinolite is the lighter green variety that usually occurs in smaller, 
longer crystals. ‘It is found at Unity and Lisbon, and is common in 
unremarkable occurrences. 


MINERALOGY. 61 


Tremolite is the white variety containing no iron. It is noticeable at 
Bedford (near the Devil’s Den, abundant), Gilmanton, and Warren. 

When this variety of amphibole crystallizes in fine capillary form, 
it is called asbestus. This variety is found at Franconia in masses or 
sheets which are from one to two inches thick, and composed of the 
finest interwoven fibres. This is called mountain leather. It is notice- 
able, also, on Monadnock mountain. A fibrous, dark colored variety, 
resembling fossil wood, is found at Lebanon. 

-Hornblende is a most important mineral as an ingredient of the 
rocks. In combination with feldspar, it forms our sienites, and with 
a triclinic feldspar or with quartz, it forms that wide expanse of 
diorites and amphibolites that occupies so much of the Connecticut 
valley. It is also a prominent ingredient of the eruptive rocks. It 
is common in works on lithology to divide it into two kinds,—basaltic 
and common hornblende. Basaltic hornblende is that very deep colored 
ferruginous hornblende that occurs in the basic eruptive rocks. The 
sections must be made thin, in order to make it transparent. It is usu- 
ally deep brown, and strongly dichroic. Such is the hornblende of the 
eruptive diorites at Campton falls, Dixville Notch, etc. The common 
hornblende is lighter in color, contains less iron, is more often green, and 
is not in such compact crystals, being very often in fibrous masses or 
crystals made up of numerous others. It is more or less dichroic, accord- 
ing to the depth of its color. Such varieties as actinolite, which in thin 
sections become white, of course are not dichroic, 

Hornblende is most easily recognized by its cleavage, which is so 
perfect, parallel to the sides of its first prism, that all basal sections 
appear divided up into rhombs with an obtuse angle of 124°. This 
characteristic serves for the determination of hornblende in all cases, 
save in those in which it exists in aggregations of minute crystals too 
small to exhibit cleavage, as it often does. 

The pleochroism of hornblende is so remarkable that it aids in its 
determination. Hornblende is monoclinic, and hence it is possible that 
the light traversing the crystal parallel to its three varying planes of 
elasticity may be differently colored, and this is markedly the case with 
this mineral. This is illustrated in Pl. 7, Fig. 2, which is drawn from 
the hornblende schist of Cornish. The plane of vibration of the light 


62 MINERALOGY AND LITHOLOGY. 


determined by the lower Nicol, which alone is on the microscope, is 
indicated by the arrow, and it is seen that, when the light passes through 
a basal section parallel to the orthodiagonal axis, the crystal is green, 
and, through a like section parallel to the clinodiagonal, it is bright yel- 
low, while a prismatic section, with the vertical axis parallel to the plane 
of vibration of the light, is blue. With ordinary light, the predominant 
color of these crystals is green, only varying in shade because blue and 
yellow make green, and green and yellow make green, as do also green 
and blue. In this figure it will be noticed that the crystals are not 
terminated, while the prismatic faces are well developed. This is quite 
characteristic of ordinary hornblende in the rocks. The basaltic horn- 
blende shows a very strong absorption of the light, rather than a marked 
pleochroism. The characteristics given distinguish hornblende very well 
from augite, which is not pleochroic, is right-angled in its cleavage, and 
very different in crystalline outline. 

When a section of hornblende is revolved between crossed Nicol 
prisms, the interference colors are not bright, especially in the basaltic 
varieties. Bright colors are obtained, however, with the lighter colored 
kinds. As with augite, sections containing the orthodiagonal axis are 
dark between crossed Nicols when a crystallographic axis falls with the 
plane of vibration to the light. With other sections, this is not true; 
and a section cut parallel to the clinopinnacoid, and placed with the ver- 
tical axis parallel to the plane of vibration of the light, must be revolved 
15° before it becomes dark, showing that one elasticity axis makes an 
angle of 15° with the crystallographic vertical axis. 

It has been shown that augite and hornblende are frequently associ- 
ated together in our rocks as a result of alteration; but it is also true 
that at times they are associated together in the same rock, apparently 
both being simultaneous formations. 

It has been pointed out, first by G. Rose, that these two minerals are 
referable to the same fundamental form; that is, if the prismatic planes 
of pyroxene making an angle of 87°.5 are called I, then the plane i-2 will 
correspond to the I of hornblende. In other words, the orthodiagonal of 
the hornblende crystal has twice the length of that of pyroxene. This 
makes the two minerals isomorphous in form; but since the minerals 
have different cleavages and habits of crystallization, they must still. be 


MINERALOGY. 63 


considered as dimorphous. Now it is well known that there is no variety 
of pyroxene of which there is not a corresponding variety of hornblende ; 
and so it may be inferred that only difference in condition is necessary 
to make one or the other species out of the same components. But 
where we see, as in the case of our diorites, both minerals made in 
a place where the conditions were necessarily the same, it is plain that 
the chemical conditions have also influence, and that the species are not 
strictly dimorphous, but different chemical compounds. This cannot be 
proved in the case of our rocks, since they are fine in texture and the 
materials inseparable; but as the point is of interest, I have looked about 
for materials which can be substituted. At Edenville, N. Y., there is an 
association of pyroxene and hornblende apparently analogous. At this 
place cavities in the rocks are filled with crystalline masses of the two 
species placed upon one another in all kinds of ways,—hornblende upon 
pyroxene, and vice versa, sometimes in large crystals, and again in small. 
The crystals take the commonest forms of the two species, and present: 
no peculiarities of note. A study of these specimens brings one to the 
same conclusion as does the study of our rocks. The minerals being so 
intimately associated, the conditions under which they were formed must 
have been the same; and hence it must be inferred that some chemical 
differences have determined the crystallization. Material was carefully 
selected, and analyses were made, to test this point, with the following 
results : 


Hornblende. Pyroxene. 
Silica, 42.97 51.05 
Alumina, ‘ , - : ‘ a 3 3 : II.90 2.02 
Iron sesquioxide, . 5 3 P . . i i 3.08 1.30 
Iron protoxide, . e ‘ 4 i F : ‘ 13.84 12.18 
Manganese protoxide, . : : , - 3 5 48 12 
Lime, “ ‘i 11.63 22.07 
Magnesia, 2 e a 3 é 3 : . 11.49 10.02 
Potash, . 2 E ‘ é . : : 5 . .88 sine 
Soda, . 2.73 oie apay 
Ignition, -38 +34 


—_—___ 


99.38 99.10 
These analyses show that there is a marked difference in the composition 
of the associated pyroxene and hornblende ; and indicate that the pres- 


64 MINERALOGY AND LITHOLOGY. 


ence of alumina favors the formation of hornblende, although the differ- 
ence in these two analyses in other respects is very wide,—the large 
percentage of lime in the pyroxene being marked; and it is known that 
pyroxene much more uniformly possesses a larger percentage of lime 
than does hornblende. The presence of alkali in the hornblende is also 
noticeable. Hence we see that when these minerals are associated, 
analysis shows them to be different chemical compounds. 

The occurrence of associated pyroxene and hornblende in the cavities 
of the lava at Vesuvius has been described by Vom Rath.* He has 
shown that these minerals have been deposited in these cavities by a pro- 
cess of sublimation, and hence, both were formed under the same condi- 
tions. His analyses were necessarily imperfect, since the very small 
amount of material that he possessed did not allow of the determination 
of all the ingredients; yet the same distinctions between his analyses 
of pyroxene and hornblende are prominent,—a larger percentage of 
alumina, a smaller of lime, and the presence of alkali in the hornblende. 

Moreover, some of our igneous rocks contain pyroxene, and others 
hornblende, and some both. Now, since these rocks form well defined 
dykes, and possess those characters which make it perfectly evident that 
they reached the surface in a molten condition, it might be inferred that 
the minerals in them were formed under essentially the same conditions. 
At Dixville Notch the traps are in part diorites, which contain horn- 
blende in such large and well formed crystals that the separation of pure 
material for analysis is easy. Now this compared with my analysis of 
pyroxene, picked from the triassic trap of the Connecticut valley,f gives 
us the results that follow: 


Hornblende. Pyroxene. 


Dixville Notch diorite. New Haven trap. 
Silica, . ‘ : ‘ ‘ a 40.79 50.71 
Alumina, 3 3 ‘ - ‘ 17.36 3.55 
Tron sesquioxide, . . a . 3-83 esas 
Iron protoxide, . r - - 15.04 15.30 
Manganese protoxide, . : ‘ +30 81 
Lime, . . ‘ : . : 10.83 13.35 
Magnesia, . ‘ A ‘ é 6.97 13.63 


* Pogg. Annalen Erganzung, Bd. vi, p. 229.” 
}t American Fournal of Science, iii, vol. ix, p. 187. 


MINERALOGY, 65 


Alkali (by difference), . .  . 417 1.48 
Ignition, . . e . . “71 1.17 
100.00 100.00 


Here, again, the same results are evident, the preponderance of alumina 
in the hornblende being the most striking difference. 

But in the case of the pyroxene at Edenville, and also in some of our 
igneous and metamorphic rocks, the pyroxene has changed its cleavage 
and optical properties, and become hornblende. The minerals have not 
become hydrated, or the iron oxidized, as in ordinary decomposition ; but 
a change has been effected without any alteration of composition, form- 
ing the mineral which was called by Rose uralite, which is pyroxene 
having the inner structure and optical properties of hornblende. In 
this case it is evident that pyroxene and hornblende are dimorphous 
forms of the same composition; that is, the molecules of the original 
pyroxene, under the subsequent influences, have rearranged themselves. - 
Tschermak has noticed that crystals of pyroxene with crumpled ends 
are the ones most liable to this kind of alteration. This is the case with 
the Edenville crystals, but whether it be a result or a cause of the altef- 
ation is not plain. 

From these analyses, it appears that any given composition capable of 
forming pyroxene, may, under different circumstances, form hornblende, 
and hence the two minerals are dimorphous forms of the same material ; 
but that under uniform conditions, chemical composition will atten 
what species shall be formed, and alumina is an important agent in this 
determination. 

Now, in the decomposition of rocks and the redeposition of sediments, 
the lime that is held in their composition is most apt to be dissolved and 
carried away in solution, and thus we-obtain those immense beds of lime- 
stones, whereby the sediments are left more aluminous ; and so in meta- 
morphic rocks there is a much greater tendency to the formation of 
hornblende; and our stratified basic rocks are mostly diorites and amphib- 
olites, while the amount of metamorphic pyroxenic rocks is small. As 
confirmation of this, see the following analysis of hornblende from the 
diorite of Littleton: 

VOL. Iv, 9 


66 MINERALOGY AND LITHOLOGY. 


Silica, . . : ; : : . : 3 : : + 49.03 
Alumina, . F . . es F 3 : . . 5 e 13.72 
Iron protoxide, * : . . . o : ‘ 9.84 
Manganese protoxide, . 5 és . ‘ ‘ ‘i a . 40 
Lime, és . . ‘ : 5 : , : ‘ Fi 11.22 
Magnesia, é “ 5 2 ‘ ‘ F 3 e a 11.96 
Soda, . ¥ ‘ . ‘ i é 3 é 3 . 2.40 
Water, qi p ‘ 5 c ‘ < : ‘ . 90 

99-47 


This is the variety of hornblende that is called pargasite, and which 
oft-repeated analyses have shown to be the common hornblende of green 
diorites, in all localities. This hornblende, the analysis of which is given, 
is a foliated variety, and by some is supposed to be a mixture of horn- 
blende and pyroxene. In our rocks, at least, it is all hornblende, and its 
aluminous nature is what I wish to call attention to in this connection. 

Hornblende is subject to decomposition, perhaps not so readily as 
augite, but yet in an analogous way. In the rocks it is liable to be hydra- 
ted, and to be changed into chlorite, and sometimes it breaks up into a 
variety of products at once ; and although the external form remains, mi- 
croscopic sections show that it is composed within of the most heterogen- 
eous mixture. Fig. 3, on Pl. 7, represents such a crystal drawn from a 
section of the diorite which forms a dyke near the Profile house, Franconia. 
It has the form of a quite perfect crystal of hornblende, but now it is com- 
posed of magnetite, biotite, and calcite, with remnants of hornblende. In 
many of the crystals in this rock the alteration has been complete. I am 
inclined to think as Zirkel does, in his consideration of analogous augite 
crystals, that the biotite was an enclosure, as calcite encloses sand, for 
crystals, apparently undecomposed, are often penetrated by it; but the 
magnetite and calcite are products of decomposition. 


45. Beryy [Be; Al, Sig Ors]. 


The largest beryls of the world are found in New Hampshire ; indeed, 
our beryls are cited in every text-book to illustrate to what proportions 
crystals can grow under favoring circumstances. Grafton and Acworth 
are the most celebrated localities for great beryls. It is a hexagonal 
mineral, and some of the large crystals have very perfect hexagonal forms, 
though they lack the lustre and transparency possessed by the small 


MINERALOGY. 67 


crystals from the same localities. The form and dimensions of two of 
these large crystals from Grafton are shown in Figs. 4 and 5 on Pl. 3, which 
represent the outlines of the bases and the dimensions in inches. The 
measurements were made by Prof. O. P. Hubbard,* who attempted their 
extraction, in which effort one was destroyed. The other one has since 
been broken up and scattered abroad. These crystals are among the 
largest that any species of mineral has ever afforded, and it is sad that 
the best specimens should have been destroyed. Their form is as regular 
as hexagonal crystals of smaller size will average. The crystal, the base 
of which is represented in Fig. 4, was originally six and a quarter feet long. 
These beryls, when of this enormous size, are apt to have subordinate 
planes, as is shown at @ in the drawing. The crystal from which Fig. 5 
is drawn, weighed over two and a half tons. One beryl extracted from 
the Acworth quarries is four feet long, and two and a half feet in diame- 
ter. The one that is preserved in the rooms of the Boston Society of 
Natural History is represented in the frontispiece, with a scale below it 
representing its dimensions in feet. 

These large crystals are of a pale green color, and many of them have 
been extracted, and are exhibited as great curiosities in the museums of 
the world. Some very large crystals still remain in the quarries, where 
they can be seen; but their extraction is a matter of considerable expense, 
since much rock must be moved in order to obtain them, and, moreover, 
it is very hard to get them out whole, since the material of which beryl 
is composed is very brittle, and filled with rifts, and a jar is sufficient to 
break them when they are not well supported. The large crystals have 
always been securely hooped before any attempt was made to move them. 
Prof. Hitchcock has obtained one for the state museum, weighing half 
a ton. 

Smaller but much more perfect and beautiful crystals are found in the 
quarries from which these large beryls are obtained, and also in other 
localities. They are usually terminated by a smooth basal plane, but 
often have in addition the planes of an hexagonal pyramid. Canaan, 
Wilmot, Springfield, Danbury, the islands of Lake Winnipiseogee, the 
northern part of Rumney, Chatham (in the stream near the path to Bald- 
face), Campton, New Ipswich, Sullivan, Plymouth, Wilmot, New London, 


* Hubbard, Am. ¥. Sei., ii, vol. xiii, p. 264. 


68 MINERALOGY AND LITHOLOGY. 


Millsfield, Groton, and Warren, are localities. They are found at many 
places in the White Mountains, and less noticeable crystals occur else-< 
where. The crystals obtained from the places mentioned are fine, the pre- 
dominant color being green; but yellow and blue crystals are also common. 
The larger crystals are filled with impurities that make them cloudy, or 
even white and opaque like feldspar; but often crystals are obtained which 
are so clear, and of such a fine color, that they have been cut into gems 
of rare beauty. The green color that predominates has been shown by 
analysis to be due to a trace of chromium, which, when present in greater 
amount, gives the green color to the emerald. Clear crystals, when found 
in the quarry, are difficult to extract without producing flaws in them, 
and hence the stones from which the most beautiful jewels have been 
cut, have been dug up from the neighboring soil, where they were depos- 
ited by being washed out from the decomposing granite. There is a 
theory among the people, that by lying a long time in the soil they ac- 
quire a heightened brilliancy. The rare beauty of these specimens is 
rather to be attributed to the fact that they have not been subjected to 
the jars produced by sledges and powder. 

The beryls are found in granitic veins. These veins are easily recog- 
nized by the very large crystals of quartz, feldspar, and mica, which are 
the constituents of ordinary granites; and the general presence of beryls 
in them is interesting, as substantiating the theory of their formation. 
These granitic minerals occupy large fissures, and it is thought that 
water, which had filtered through the surrounding rocks,.and which, un- 
der a high pressure, and at a high temperature, had become saturated 
with their soluble constituents, deposited these great crystals of the va- 
rious minerals in these fissures, until they were finally filled with this 
extremely coarse granitic mixture. In this way, the rarer elements, such 
as glucinum, which exist in such minute amounts in the surrounding 
rocks, became concentrated in these veins, forming the beryls that are so 
common theré. These veins are worked at various points, in order to 
obtain the great crystals of mica, which are very valuable. 

Some beryls from New Hampshire have been analyzed. The analyses 
are both made upon specimens from Acworth. The first is by Prof. C. 
A. Joy.* The second is by M. B. Williams: + 


* Am. ¥. Sci., ii, vol. xxxvi, p. 91. + Geology N. H.,C. T. Jackson, p. 182. 


MINERALOGY. 69 


I. II. 
Silica, . . F 3 : 4 ; : 68.84 68.35 
Alumina, yi - . : ‘ . 7 16.47 17.60 
Glucina, . é c $ 4 . 3 13.40 14.00 
Iron oxide, . 5 ‘ . 5 5 1.70 trace. 
Chromium oxide, . ‘ - : é - trace. 
100.41 99-95 


The analysis by Prof. Joy is the result of an extended series of experi- 
ments which were made with the view of finding the best methods to 
analyze this species, and to obtain glucina in a state of purity in order 
to study its properties and its salts. 

The fracture of beryl is vitreous. It sometimes shows a basal cleav- 
age, and this cleavage is very marked and perfect on the very large 
specimens. 

A thin section of one of the large beryls from Grafton shows that the 
crystal is filled with microscopic impurities. Its appearance under the 
microscope is represented in Fig. 4 on Pl. 4. There are amorphous sub- 
stances that have filtered into the cracks; and there are crystalline sub- 
stances. These latter are all prismatic, and are arranged with an edge of 
the prism parallel to the long axis of the beryl. The minerals are those 
that are common in the granite veins. There are little black tourma- 
lines, and scales of black mica. Beside these there are minute particles 
that polarize the light like quartz, and numerous cavities that are filled 
with water, each one containing a bubble of air. These cavities are 
generally wholly irregular, but others have a perfect hexagonal outline, 
with the long axis and the sides parallel to those of the large crystal. 
Like the other cavities, they contain a fluid and a bubble. Most of these 
cavities probably contain water; but one that I examined apparently 
contained two fluids, and the bubble disappeared at a temperature of 30° 
centigrade. It therefore contained liquid carbonic acid, which has been 
shown by Sorby and others to be common in beryls. 

The expansive force of liquid carbonic acid at 0°, C. is 36 atmospheres, 
and increases one atmosphere for every added degree of temperature. 
If, as is likely, the temperature was an elevated one under which these 
minerals were formed, the pressure must have been immense. 


7O MINERALOGY AND LITHOLOGY. 


46. CurysoLiTEe (OxIvine) [(Mg, Fe), Si Oy]. 


This mineral is a prominent ingredient of some of our igneous rocks. 
It was first noticed as an ingredient of the trap at Campton falls by 
Prof. O. P. Hubbard,* who also found it forming masses of some size 
in a very coarsely crystalline diabase, which is found in boulders (the 
original locality for which is not known) at Thetford, Vt. It was ident- 
ified in the gabbro from Waterville + by Mr. E.S. Dana. When visible to 
the eye in the rocks it has a vitreous lustre, and a greenish yellow color. 
The easy decomposition to which it is subject makes it conspicuous; 
and rocks like our gabbros, which, when broken, show the clearest and 
freshest grains of chrysolite on a fresh fracture, are externally covered 
with iron-stained pits, from which the chrysolite has rotted away. It has 
been found, also, in granite boulders near the Crawford house. 

The following is an analysis of the chrysolite from the Waterville 
rock, by Mr. Dana. 


Silica, . 5 3 ‘ ‘ 5 és . ; . 7 - 38.85 
Alumina, . ‘ ‘ 7 F ‘ ‘ F 2 F @ : trace. 
Iron protoxide, , 3 i ; , P . . . : 28.07 
Manganese protoxide, . . ‘ . ‘ E a . 1.24 
Lime, . 7 ‘ . F e . - 7 . ‘i 1.43 
Magnesia, : ‘ : ‘ ; we t% ‘ 2 - 30.62 

100.21 


The analysis shows this to be the variety of chrysolite which com- 
monly occurs in rocks, and which is usually called olivine. It contains 
an unusually large amount of iron,—as remarked by Mr. Dana, the pro- 
portion between the iron and magnesia being as 1:2. Hence the 
formula for this olivine is 


ies ot 


When present in sections of rocks prepared for microscopic study, 
chrysolite is easily recognized. When crystalized, its sections are either 
six- or eight-sided, the figures being the sections of the most common 
form of the crystals of this species. This form is made by a combina- 
tion of two prisms and a macro- and brachydome. In the rocks that I 
have examined, the sections at right angles to the vertical axis appear 


* Am, Four. Science, i, vol. xxxiv, p. r10. + Id., iii, vol. iii, p. 48. 


MINERALOGY, TI 


quite imperfect, indicating a poor development of the prismatic planes, 
while the sections parallel to the vertical axis show beautiful six-sided 
forms, being combinations of the edges of a prism and dome. The ap- 
pearance of the olivine in the olivine diabase of Campton falls is repre- 
sented in Fig. 4 on Pl. 7. Beside these crystalline outlines, the micro- 
scopic peculiarities of olivine are very characteristic. As a rule, its 
cleavage is wholly irregular, though cases are not wanting in our rocks 
where it gives evidence of a very perfect cleavage parallel to the plane 
of the macropinnacoid. The crystals are dark between crossed Nicol 
prisms when a prismatic edge or a cleavage, when evident, is parallel with 
the plane of vibration of the light. The interference figures produced by 
olivine, when revolved between crossed Nicol prisms, are very brilliant. 

The decomposition of olivine is very characteristic. As before stated, 
it decomposes with great ease; and almost always, in microscopic sections, 
decomposition products of one kind or another are found about the fract- 
ures or cleavages, which have admitted the reagents that act upon it. 
In the olivine of our gabbros, alteration has not progressed far; but in 
the diabases the alteration is almost complete. For example: in the crys- 
tals figured from Campton falls, the material about the cracks is a differ- 
ent substance from the olivine, and is of a light yellow color. By its 
action on the light, it is recognized as serpentine, the common product 
that results from the hydration of olivine. This shades off into a greenish 
yellow fibrous serpentine, while only the centres of the larger crystals are 
still intact. All these different products are brought into the strongest 
relief by the aid of polarized light. Many crystals have been observed 
and described by Zirkel and others, that are entirely altered into serpen- 
tine; and the well known crystals from Snarum, in Norway, afford excel- 
lent macroscopic illustration of this change of olivine into serpentine, 
which the microscope finds so common. 


47. Garnet [R; R Si, Ou]. 


R, in our species, standing for lime, protoxide of iron, and manganese; 
R for alumina and sesquioxide of iron. 

Garnet is a common mineral in our metamorphic rocks. It is found 
usually in very perfect crystals, the forms being the dodecahedron and 
the tetragonal trisoctahedron or trapezohedron, and, again, it is found in 


72 MINERALOGY AND LITHOLOGY. 


large masses, which are destitute of any crystalline form. We possess 
quite a variety of garnets, the prominent varieties being the red iron 
alumina garnet called almandite; the manganese iron alumina garnet 
“called spessartite; the lime alumina garnet called cinnamon garnet or 
grossularite; and the lime iron garnet called andradite. 

The red almandine garnet is common in the hornblendic rocks of the 
Connecticut valley, and also in the gneiss and mica schists all over the 
state. Sometimes, as at Hanover, the crystals are nearly clear, and 
resemble the stones from which the gems are cut, but more commonly 
they are only translucent. They vary in size from microscopic grains to 
crystals an inch in diameter. They are commonly dodecahedral, though 
the edges are often replaced by small planes of the trapezohedron. They 
are found in the most perfect forms in chlorite rocks; but small and very 
perfect crystals are found in the greatest profusion in some of the horn- 
blende rocks. This variety of garnet is found in a chlorite rock at Haver- 
hill, in large crystals 14 inches in diameter. Newington, Lisbon, Unity, 
Orford, Dorchester, Dalton, and Windham are localities for it, and it is 
common in some of the mica schists and granitic rocks of the moun- 
tains, though the crystals are not so often perfect. Sometimes fine crys- 
tals are dug from the soil where they have been deposited after the disin- 
tegration of the rocks; and from this source the finest pieces for cutting 
have been obtained. This variety of garnet is common in the great 
granite veins like those at Acworth and Grafton. Clear and beautiful 
little crystals, and large imperfect ones, are abundant. Very large and 
perfect crystals have been found in the granite veins at Winchester. 
They are trapezohedral in form, but have the planes of the rhombic 
dodecahedron, 

Spessartite—the silicate of manganese, iron, and alumina—is most 
common in the mica schist rocks. Its crystals are usually larger. It 
commonly crystallizes in trapezohedrons, though the planes of the dodec- 
ahedron are often seen. A great many of them have been obtained by 
mineralogists from the mica schist at Springfield, where they are very 
abundant, and very perfect in their crystallization. 

Andradite—the lime iron garnet—is very dark in its color, being .deep 
blood-red, and often nearly black. It has been identified by W. Fisher * 


= American Journal of Science, ii, vol. ix, p. 84. 


MINERALOGY. 73 


as occurring at Franconia, Massive garnet in large pieces is found here, 
in the geodic cavities of which beautiful blood-red crystals are found asso- 
ciated with calcite and magnetic iron. The following is an analysis, by 
Fisher, of a nearly black specimen from this locality : 


Silica, F 38.85 
Iron sesquioxide, . ; : - ‘ ‘ , ‘i : : 28.15 
Lime, E 5 é 5 ‘ . 3 - . . . 32.00 

99-00 


The analysis shows, as he remarks, that it is a pure iron lime garnet, 
remarkably simple in composition, the analysis of which corresponds 
very exactly with the formula. 

The most beautiful garnets that have been found in New Hampshire 
are perhaps the cinnamon or alumina lime garnets which are found 
associated with green pyroxene at Warren and at Amherst. They are 
of a cinnamon-brown color; and the ones at Warren are very perfect in 
their form. The Amherst crystals reach a very large size, some of them 
being three or four inches in diameter; but when so large they do not 
often have perfect and smooth crystalline faces. These crystals are 
found in the limestone, and also in the crystalline rocks, at their surfaces 
of contact with the limestone. They are mostly simple dodecahedrons, 
They are associated with pyroxene and vesuvianite, which are other lime 
and alumina minerals. Dr. Jackson, in describing these rocks, has fol- 
lowed some others in thinking that the occurrence of these lime silicates 
at the junction of the limestone with the siliceous rocks, or primary rocks, 
as they were termed, is sufficient evidence to prove that all these rocks 
were of igneous origin, since the siliceous rocks on eruption would 
inevitably generate such silicates of lime and alumina as garnet and 
vesuvianite, on coming into contact with the limestones. But this is 
not a weighty argument. Garnet and vesuvianite are minerals which, 
although unaffected by acids in fine powder, are decomposed by hydro- 
chloric acid with ease if they are ignited before treatment, and the solu- 
tion, if evaporated, will gelatinize. This shows that some chemical 
change is effected by heating a garnet, and therefore a garnet would 
not be likely to be formed at a high temperature; and, as is well known, 


it is not often found as a constituent of igneous rocks, save as a product 
VOL. Iv. 10 


74. MINERALOGY AND LITHOLOGY. 


of their decomposition. It is very probable, however, that by metamor- 
phic and other agencies garnets might be formed, as they so often are, 
on the junction of siliceous rocks and limestones; but it is on account 
of the proximity of the chemical elements which by reaction on one 
another may form garnets, and is not any proof of the igneous condi- 
tion of either mass. 

Garnet is often present as a microscopic constituent of our rocks. It 
seems likely to exist anywhere, save in the basic eruptive rocks. When 
present in microscopic preparations it is recognized by its optical deport- 
ment, since, owing to its single refraction, its sections, in whatever direc- 
tion they are cut, are dark in all positions between crossed Nicols. In 
the schists the garnets are usually crystalline; and then their sections are 
commonly six- or eight-sided, being sections of dodecahedrons, but often 
they are nearly round. In the granites, on the contrary, the garnets 
frequently have no crystalline outline, but have a most irregular and 
eccentric structure, and look like melted bits of glass. Garnet has no 
cleavage, and its sections are usually traversed by rifts, which go in all 
directions. 

Some beautiful specimens of garnets, all mounted and in readiness for 
microscopic study, are found in our granitic veins. These are garnets 
which, having crystallized between plates of mica, are flattened out, and, 
instead of appearing as natural crystals, look like thin flat discs fastened 
in the mica. They form very pretty objects, and are thin enough to be 
studied with the microscope. Lasaulx* mentions one of these garnets 
which was all penetrated by little crystalline needles of tourmaline. 
Other microscopic impurities, such as quartz, magnetite, and epidote, are 
often present in garnets, and sometimes a garnet will have cavities in it 
of crystalline form. 

The garnets that occur in the hornblende schist at Hanover are very 
interesting as a microscopic study. They are well crystallized in perfect 
dodecahedrons, and to all appearance are perfectly pure, many of them 
being quite clear, and of a beautiful wine color; but when a thin section 
is cut through one of these, it is seen to be filled with grains of quartz, 
which in many cases constitutes at least one third of the whole. Fig. 5 


« Elemente der Petrographie, Dr. A. Von Lasaulx, p. 80. 


MINERALOGY. 75 


on Pl. 4 is drawn from one of these garnets, and shows it as it appears 
when magnified twenty diameters. When this section is examined be- 
tween crossed Nicols, the garnet becomes black, but the quartz springs 
out into brilliant colors. The garnet does not enclose any of the horn- 
blende of the rock, but it does sometimes enclose a piece of magnetite. 
This seems to be a remarkable case of impurity, which reminds one of 
the Fontainebleau limestone, which is carbonate of lime, the crystals of 
which sometimes contain half their weight of sand. In our garnets, 
however, the quartz, being transparent, does not become evident until a 
thin section is made; and no Better illustration than this can be found, to 
show the value and necessity of microscopic work in connection with 
mineral determination, since experience shows that analyses made on 
apparently pure material may be worthless, on account of the presence 
of weighty impurities. 

Garnets are common in the clay slates of the Connecticut valley. In 
them a very pretty process of pseudomorphism can be seen in progress, 
which is represented in Fig. 5 on Pl. 7. Here a garnet perfect in out- 
line is slowly changing into chlorite. The chlorite in this specimen is 
arranged concentrically about the garnet in foliated masses. In other 
specimens that I have seen, from other localities, the foliz of chlorite 
were arranged radially. Prof. R. Pumpelly* has described and figured 
garnets from the Lake Superior region that were almost entirely changed 
into chlorite. The garnets in these slates also contain some quartz, but 
not as much as the Hanover crystals. 


48. Zrrcon [Zr Si Ox]. 


This mineral is found as a microscopic constituent of some of our 
granites and sienites, but I am not aware of its occurrence in macro- 
scopic crystals. Zircons in the granite are not very common, but the 
crystals, though very minute, are often perfect in form. Fig. 1 on Pl. 5 
represents some crystals of zircon in the Fitzwilliam granite. They are 
highly magnified. As is seen, some of the crystals show the perfect 
quadratic base, and others show the prism. Again: some of the crystals 
are rounded, and yet approximate to the form of zircon. The dark min- 
eral on the sides ‘of the figure is biotite. The zircons are bedded in 


* American Fournal of Science, iii, vol. x, p. 17. 


76 MINERALOGY AND LITHOLOGY. 


quartz. Some of these little crystals exist in the sienite at Sandwich, 
and are there very perfect in form. 


49. VESUVIANITE (IpocrasE) [Cag Al, Si, Ong]. 


Large and fine crystals of vesuvianite have been found at Amherst, 
and also at Warren. These crystals occur on the surfaces of contact of 
the limestones and siliceous schists that are there associated. One of 
the crystals from Amherst is represented in Fig. 2 on Pl.3. It is taken 


from the second edition of Dana’s Mineralogy. 
e 


50. Eprpote [H? Ca‘ (Al, Fe”)? Si® O*]. 


We have epidote both in isolated crystals and in our rocks. It is 
found at Lisbon in light yellow acicular crystals, and in larger, finer forms. 
Very pretty twin crystals, and also a massive variety, are found there. It 
occurs at Warren, associated with quartz and pyrites. It fills a vein in 
Jackson, from which immense crystals have been taken, some of which 
were eight inches in diameter and of a fine green color (Jackson). Smaller 
but better crystals, and also twins, are more common. It is found at 
Bedford, Gilmanton, Hanover, Portsmouth (radiated acicular crystals in 
hornblende), Exeter (very beautiful groups of radiating crystals), and 
Benton (in boulders). 

As a rock constituent, epidote is preéminently characteristic as a 
decomposition product in certain basic rocks. It is found in seams and 
cracks in the metamorphic diorites that are so common in the Connecti- 
cut valley, and is an almost constant microscopic ingredient of the rocks 
themselves. The same is true of some of our eruptive rocks. In micro- 
scopic sections it is trichroic; but the colors are often so faint as to 
render the recognition of this difficult. It may be said, however, that it 
is usually yellow in color, and, when revolved between crossed Nicols, the 
colors obtained are perhaps more brilliant than those shown by any other 
mineral. 

Where the rocks contain the most basic feldspars, and where this feld- 
spar is dull by decomposition, there epidote is most often found. In our 
light green feldspathic diorites, epidote seems to be the mineral most 
commonly found in and about the triclinic feldspar as a product of its 
decay. At times, this process of alteration has proceeded so far that 


MINERALOGY. 77 


nearly all traces of the triclinic feldspar has disappeared, and a green 
rock, with nearly the composition of epidosite, is the result. Examples 
of this are to be found in Cornish and Stewartstown, where all stages 
of the progress of alteration can be seen. In the eruptive diabases, 
epidote, resulting from alteration, often fills amygdaloidal cavities. Pro- 
ducts that result thus from decay rarely possess any definite crystalline 
outlines in the rocks; and this is the case with epidote, which commonly 
exists in very minute grains, or aggregates of grains. 


51. Zois1TE [H? Ca’ Al’ Sif OF] 


Zoisite differs from epidote in containing but little or no iron. It 
has been found in ash gray, much compressed, and deeply striated crys- 
tals at Westmoreland. It has also been found at Hanover, Franconia, 
and Lisbon. 

52. IotirE [Mg’ (Fe’, Al’)? Si O¥]. 


Very fine specimens of this beautiful mineral are found at Richmond. 
It occurs in the quartz rock and mica schist. Its color is blue, but its 
dichroism is very marked,—one species being blue when the light passes 
in the direction of the vertical axis, and brownish-violet when it passes 
at right angles thereto, the two colors obtained parallel to the two lateral 
axes being not markedly different. This mineral was found in opening 
a soapstone quarry. Iolite is also found in Unity and Croydon. This 
mineral alters with the greatest ease, the first result being the hydration 
af the mineral, then the separation of the prism by planes parallel to its 
base, and, finally, the production of a hydrous silicate, which varies much 
in composition. 

Tolites from Richmond and Unity have been analyzed by Dr. Jackson, 
with the following results : 


Richmond. Unity. 
Silica, . r 3 5 3 - - - 5 48.00 48.15 
Alumina, ; - . 3 F ‘ ‘ ‘ 35. 32.50 
Iron protoxide, 3 : 7 : F : , 6. 7.92 
Magnesia, % , . : ‘ 3 5 10. 10.14 
Manganese protoxide, . é a ‘i 5 : I. -28 
Water, . 5 : ‘ 7 : : . fe  ahewg -50 


100.00 99-49 


78 MINERALOGY AND LITHOLOGY. 


These analyses agree closely with the formula given. The iolite is 
usually found in large, flat pieces, with no crystalline planes except the 
base. Crystals with prismatic faces are not rare, but they are commonly 
much decomposed. 


53. CHLOROPHYLLITE. 


Tolite, as already stated, is a mineral that is very easily altered, and 
many of its decomposition products have been analyzed, and given dis- 
tinctive names. When Dr. Jackson made his geological survey of this 
state, he discovered at Unity (where iolite, also, is found) a hydrated 
silicate, to which, on analysis, he gave the name of chlorophyllite. This 
substance was also analyzed by Rammelsberg, who places it along with 
several other like substances in a supplement to iolite. Dana classes 
all these substances together under the name of fahlunite, a species 
belonging with the hydrous silicates. The following are the analyses of 
chlorophyllite from Unity: 


Jackson,* Rammelsberg.t 

Silica, . ‘ , . i ‘ ‘ 5 ‘ 45.20 46.31 
Alumina, . a ; : . i ; . 27.60 25.17 
Iron sesquioxide, . : : z 5 . ; 9-17 10.99 
Manganese protoxide, . . 5 : 5 ‘ 4.08 tr: 
Magnesia, ; F : : : 5 . : 9.60 10.91 
Lime, . J - . . ‘ j ‘ ey Gaseesueys 58 
Water, . a Fi : ‘ 2 : . . 3.60 6.70 

99.25 100.66 


Rammelsberg remarks that his analysis gives, on calculation, a quantiva- 
lent ratio, which is that of a definite hydrate of the species iolite, or a 
species with the same formula as iolite, plus three or four molecules 
of water. As Jackson's analysis, when compared with Rammelsberg’s, 
shows wide variations, chlorophyllite must be regarded as a product 
resulting from the decomposition of iolite. 


Mica. 


Mica in our state is an important mineral from an economic stand- 
point, and a very interesting mineral from a scientific. We have some 


* Rep. Geol. N. H., 1844. + Rammelsberg’s Min. Chem., 1875, p. 653. 


MINERALOGY, 79 


of the finest mica quarries on the continent, and much mica of the best 
quality is extracted from them. Mica is, moreover, a most common and 
interesting rock constituent. 

We have four species of mica,—biotite and lepidomelane (black micas), 
which are uniaxial, and muscovite and lepidolite (white micas), which 
are biaxial. These micas often occur together; but when their crystals 
are in contact, there is usually some simple relationship between the 
axes of the two crystals. It may be stated in general, before describing 
the species, that all these micas have the same prismatic angle. Biotite 
and lepidomelane are hexagonal and uniaxial, and have a prismatic angle 
of 120°; and muscovite and lepidolite are biaxial and orthorhombic, but 
have the same prismatic angle of 120°. The color of our granites, as well 
as of many of our schists, is largely due to the kind of mica they contain. 
Granites that contain the white biaxial micas are light colored, while the 
black micas make the granite dark colored, and the darkness is propor- 
tional to the quantity. Some granites are nearly black, on account of 
the large amount of black mica they possess. 


54. Brorire [K, (Fe, Mg)’ Al* Si? Ox]. 


Black magnesia iron mica. 

This mica varies very much in color, according to the proportion of 
iron that it contains. It is usually nearly black. It is of no economic 
value; but as has been already stated, it makes dark-colored granites, 
which, by some, are more admired than are the white granites. The 
mica in granite is generally in very small scales; but in the great gran- 
itic veins that occur at Grafton, Alstead, Acworth, etc., all the ordinary 
constituents of granite are found in very large crystals, and among them 
are interesting specimens of biotite. The biotite of these veins is very 
rich in iron, and is black by reflected light, though thin flakes of it are 
brown by transmitted light. I analyzed a specimen of it at one time 
from a granite vein in Middletown, Conn.,* and found it to be an uni- 
silicate, containing 35.61 per cent. of silica, 20.03 of alumina, 21.85 of 
iron protoxide, 5.23 of magnesia, and 9.69 of potash, with quite a list of 
accessory elements, among which were lithia, fluorine, and titanic acid ; 
and, as the physical appearance of the micas in all our granite veins is 


* American Yournal of Science, iii, vol xi, p. 432. 


80 MINERALOGY AND LITHOLOGY. 


exactly the same, it may be assumed that this is the composition of our 
black mica. 

Biotite is hexagonal. In our quarries imperfect crystals are sometimes 
found, though pieces with an irregular outline are most abundant. It 
is quite common to find it united by the edges of its laminze with mus- 
covite or white mica; as if the muscovite, after reaching a certain size, 
had gone on increasing itself with the substance of biotite. Moreover, 
when the two species have thus grown together, it is found that their 
prismatic faces are parallel to one another. Although we do not often 
have the prismatic faces to study, still we have the means for finding 
their directions. When one takes a tolerably thin piece of mica, and 
strikes it quickly with a sharp point, lines of cleavage are developed 
about the hole made by the point; and thus a figure is produced called 
a strike figure (schlag figur). Now Reusch has shown * that this cleav- 
age in hexagonal mica is parallel to the sides of the prism, and that in 
orthorhombic micas it is parallel to the rhombic prism and the shorter 
of the lateral axes. Therefore the strike figure is exactly the same in the 
orthorhombic mica that it is in hexagonal, and in each case is composed 
of three cleavages, which cross one another at an angle of 60°. If, now, 
we strike with a pointed instrument upon a piece of this mica, which 
is composed of the two species, near the line upon which they are united, 
we shall produce these cleavage lines, which will run from one species 
into the other without interruption, and without any change of direction. 
This shows that there is some simple relationship between the positions 
of the crystalline planes of the two species; and, if we draw lines to 
represent the faces of the crystals parallel to these lines of cleavage, we 
shall obtain the correct positions of the crystals, and see their relationship 
to one another. Fig. 2 on Pl. 9 represents one of these pieces of mica 
with two of the strike figures,—one on the black mica and one on the 
white; andthe lines are seen to run without interruption from one into 
the other species. The faces of the crystals are drawn parallel to these 
lines, and the relationship of the two crystals is shown. 

Biotite is easily determined by the aid of the microscope. All sec- 
tions, save those parallel to the basal cleavage, are very strongly dichroic ; 


* Monatsbericht der Konigl. Akad. Wissensch. Zu Berlin, 1868, p. 428, and 1869, p. 84. 


MINERALOGY, 81 


hence those that show the very evident basal cleavage, when revolved on 
the stage of the microscope with only the lower Nicol fixed upon the 
instrument, are light yellow when the vertical axis of the crystal is parallel 
to the plane of vibration of the light, and very dark brown or black when 
the cleavage, which corresponds to the lateral axes, is parallel to this 
plane. Sections that show no cleavage are basal sections, and, as basal 
sections of hexagonal minerals do not possess double refraction, they 
show no dichroism. It is possible to confound biotite with basaltic 
hornblende, since their colors and dichroism are much alike, though 
the cleavage of mica is different. Between crossed Nicol prisms all 
sections of biotite will be black when the cleavage corresponds with 
the plane of vibration of either Nicol, since the cleavage corresponds 
with an axis of elasticity. With hornblende this is not the case, and in 
the larger number of its sections the point of maximum darkness will 
be obtained when the cleavage makes a certain though not great angle 
with the plane of the light. 

Biotite is constantly met with in our rocks, and in many cases it re- 
quires no microscope to detect it; but in many other cases it is only 
microscopic. 

Biotite is fusible before the blow-pipe; but the ease with which it fuses 
depends upon the amount of iron that it contains. Our black biotites in 
the feldspar quarries are very rich in iron, and hence fuse without much 
difficulty to magnetic globules. Some specimens impart the bright crim- 
son color that is characteristic of lithia. There was one per cent. of 
lithia in the biotite from Middletown that I analyzed. Some of the bio- 
tite in the granites contains lithia; and the lithia-bearing varieties seem 
to be much more easily fusible than those which contain none. 

If an ordinary cleavage piece of biotite, sufficiently thin to be translu- 
cent, is put on the stage of the microscope, the ocular removed, and the 
two Nicol prisms placed at right angles to one another, the field will be 
traversed by a black cross, the arms of which do not alter their positions 
on revolving the stage. The mica is thus easily seen to be uniaxial. 


55. LEPIDOMELANE. 


From an examination of the analysis of biotite that precedes, it is 


easy to see how readily a mineral so composed would alter. Such 
VOL. IV. II 


82 MINERALOGY AND LITHOLOGY. 


highly ferruginous minerals, when the iron is present in the state of 
protoxide, are very subject to oxidation. A number of such micas have 
been analyzed, and they show no essential difference from such a biotite 
as that last described, save that they contain a large proportion of iron 
sesquioxide, and are black and opaque, and more or less brittle. The 
optical properties, when they can be made out, are identical with those of 
biotite. These micas, containing sesquioxide of iron in the place of 
protoxide, are called lepidomelane. Many specimens of mica which 
are found in the granite quarries and rocks of New Hampshire would 
be referred to this species. It is distinguished from pure biotite by its 
opacity, its lack of elasticity, and its black shiny lustre. It fuses before 
the blow-pipe to a magnetic globule, and is easily decomposed by acids. 
In the microscope it has the same optical properties as biotite, and it is 
common in some of our granitic rocks. Prof. J. P. Cooke* describes 
a variety from Cape Ann, which has been named annite, which differs 
from what is considered typical lepidomelane in containing a less pro- 
portion of iron sesquioxide, and a greater of protoxide. We have, in some 
of our granites, micas which exactly answer to this in physical proper- 
ties; a granite from Farmington contains mica like this, which gives 
the reaction for lithia that is obtained from annite. Prof. Cooke, thinking 
this to be owing to an impurity, deducts the percentage of lithia ob- 
tained ; but as my analysis shows that lithia exists in pure biotite, I 
think that our micas that I have examined, and which give a lithia reac- 
tion, doubtless contain it in their composition. 

The optical properties of lepidomelane under the microscope are 
identical with those of biotite. It is quite likely that a large proportion of 
the black mica in our rocks might be referred to this species; but in 
lithology no distinction between lepidomelane and biotite is recognized, 
and all the black dichroic micas are called biotite. 


56. MuscovitE [K? Al? Si? O%]. 


Muscovite, or common mica, is one of our most valuable minerals. 
Besides its universal distribution over the state as a rock constituent, 
large amounts of it are extracted from the granitic veins, where valuable 
plates, sometimes a yard across, are found. Grafton, Alstead, Acworth, 


* Am. Your. Science, ii, vol. xliii, p. 22. 


MINERALOGY. 83 


and Springfield, are towns where large granitic veins have been worked 
with profit for the mica, and the Grafton mica mines are still in very 
successful operation. Alexandria, Orange, and Groton are other local- 
ities. Much further reference to these occurrences of mica will be found 
in the chapter on economic geology. 

Muscovite is orthorhombic, and the angle of its prism is 120°. The 
crystals appear sometimes nearly hexagonal, on account of the develop- 
ment of the brachy-pinnacoid. In Wilmot, large crystals, six inches in 
diameter, are found, which by the combination indicated appear nearly 
hexagonal. Gilmanton, New London, and Hinsdale, beside the mica 
quarries already mentioned, furnish fine crystalline varieties of musco- 
vite. This mica is usually colorless, or smoke color in thicker plates ; 
but green and yellow muscovite is found at Bedford, rose-colored at Wal- 
pole, green, white, and brown at Piermont, and green at Unity. All 
shades of yellow result from alteration, and an opaque gold color is 
often the last product of change. 

The association of minerals with muscovite in our granitic veins is very 
interesting. Its union with biotite according to a definite rule has been 
already mentioned under that species. The simplest case of that asso- 
ciation is where plates of black and white mica are united by their edges, 
as illustrated in Fig.9g on Pl.2. The cleavages developed by a blow with 
a sharp point are parallel in the two species, and, as shown by Reusch, 
these cleavages are parallel to the prismatic faces of the two species. 
The sides of the hexagon on the biotite may therefore be drawn, but 
the prism of muscovite might be drawn with its long axis in three 
different directions. If now we remove the ocular from the microscope, 
on looking through the biotite with the Nicol prisms crossed, the strictly 
uniaxial character of the mica will be seen by the clear black cross, the 
arms of which cross one another in the centre of the field. (Biotite is 
not always so strictly uniaxial.) Muscovite is orthorhombic, and the 
vertical axis is the acute bissectrix; and in our crystals the plane of the 
axes appears always to be that of the macrodiagonal. If now, with the 
ocular removed, we look at the muscovite, we see its two optic axes, and 
the direction of the line connecting them is the longer diagonal of the 
rhomb. These observations are represented in the figure; @ and J are 
the cleavages produced by blows, and the appearances of the optic axes 


84 MINERALOGY AND LITHOLOGY. 


of the two micas, as they appear between crossed Nicols without the 
ocular, is also shown. These data give us the position of the crystals, 
which are seen to be connected by their prismatic edges. 

In addition to that union of plates by a simple edge, there are also 
found specimens in the mica quarries where plates of muscovite partially 
or wholly surround a crystal of biotite; and here the same symmetry in 
the arrangement of the prismatic planes is made evident by a determina- 
tion of the positions of the planes of the muscovite. This was investi- 
gated by Gustav Rose,* and Fig. 9 on Pl. 3 is the one drawn by him 
from a specimen from Alstead in our state. In this figure, a represents 
the direction of the cleavage induced by a blow with a sharp point, and 
é represents the direction of the plane of the optic axes, and the relation- 
ship of the two figures is thereby easily identified. 

Every one who has seen the mica as it comes from these quarries must 
have noticed how it is traversed at times by a straight crack, and that on 
breaking it in two, this straight cleavage crack is filled with a multitude 
of little fibres which are parallel to the direction of the line. At times 
these natural divisions spoil a fine large sheet of mica, and at times a 
piece of mica is divided by these divisions into a number of long strips. 
Now Reusch and Bauer, who have studied the little cracks produced by 
striking mica, have demonstrated that in muscovite a sharp blow with a 
hard point develops a cleavage parallel to the sides of the prism and to 
the shorter diagonal, as already shown; but it was also found that by 
pressure with a rounded point a little six-rayed star could be formed, the 
arms of which were cleavages not parallel to the sides of the prism, but 
at right angles to them. If, now, we take one of our sheets of mica with 
a straight edge produced by natural division, and strike upon it with a 
sharp point near the edge, we shall find that this edge is never parallel 
to any of the little cleavage lines, but always stands at right angles to 
one of them, and hence corresponds with one of the cleavages that can 
be induced in the mica by pressure. This is illustrated in Fig. 10 on Pl. 
3. Ata, a cleavage induced by a sharp blow is shown, which indicates 
the direction of prismatic planes; and at 4, a cleavage induced by pres- 
sure is shown, and the natural edges of this strip of mica stand at right 
angles to a blow cleavage, and parallel to a pressure cleavage; and hence 


* Monatsbericht der Konigl. Akad. der Wissenschaften, Berlin, April, 1869, p. 339. 


MINERALOGY. 85 


we can conclude that these divisions in this mica are cleavages that were 
produced in it by pressure resulting from some dislocating agency after 
the mica was formed. The fibres that lie in these cleavages are only 
much smaller cleavage strips. 

Beside enclosures of a different species of mica, other minerals are 
found between or attached to plates of mica, and these minerals have all 
the peculiarity of being flattened out into discs, ribbons, or net-works,— 
forms induced on them by the crystallization of the mica. For example: 
garnets are found in the mica, which, instead of being ordinary dodeca- 
hedrons or trapezohedrons, are flattened discs; and when the mica is 
scaled away till it is of the same thickness as the garnet, it forms a nat- 
ural setting around the crystal, which, with its fine wine color, looks very 
pretty in its yellow mica surroundings. Flattened crystals of tourmaline 
are very common. The crystals are often so thin by reason of this flat- 
tening, that they are quite transparent, and the effects of polarized light 
can be observed by using two of them. The minute crystals that are 
best seen with the aid of the microscope are the most perfect, and must 
be extremely thin. Two little crystals, that by chance cross one another 
at right angles, are shown in Fig. 10 on Pl. 2 as they were found in a piece 
of mica from Grafton. Nature has here prepared for us the experiment 
which is tried by every one in the beginning of the study of optics,—to 
show the beautiful principle of polarized light. Other minerals are also 
found. Magnetite, so thin as to be translucent; quartz, in little net-works 
of flat crystals; feldspar, in thin, white plates; and beryls flattened into 
ribbons are not uncommon. 

Muscovite is easily recognized in microscopic sections of the rocks by 
its white color and its ready cleavage, which, in all but basal sections, is 
very plainly evident in the straight lines which traverse it in but one 
direction. Its sections are always black between crossed Nicols when 
its cleavage is parallel to the plane of vibration of the light; and all its 
sections, whether basal or not, are four times dark in a complete revolu- 
tion between the crossed Nicols. It has hence all the properties of an 
orthorhombic erystal. It commonly is found in rocks in irregular bits 
destitute of crystalline outline; but in the granites it does make efforts 
to crystallize, as is often macroscopically evident. In the Roxbury gran- 
ite, the microscope detects the most innumerable, very minute, yet most 


86 MINERALOGY AND LITHOLOGY. 


perfect crystals. This granite contains both muscovite and biotite in 
comparatively large scales, with no crystalline form; but some of the 
grains of quartz are filled with the finest little muscovite crystals. A 
section of this rock is represented in Fig. 2 on Pl. 5. On changing the 
focus, many more of these crystals are brought into view. The large 
mineral above is muscovite, and the black one on the right is biotite. 


FELDSPAR. 


In a state like ours, which is covered by crystalline rocks, feldspar is, 
next to quartz, the predominant mineral. All the feldspars of litholog- 
ical importance are well represented, the species being,— 


Anorthite, Ca Al? Si2 O8. 

Labradorite (Ca Na), Al? Si O19, 

Andesite (Ca Na2), Al? Sit O12, 

Oligoclase (Ca Na? K2), Al? Sid O14, 

Albite, Na? Al? Sis O18, 

Orthoclase, K2 Al2 Sis 018, 

Microcline, 

It is useless to give localities for specimens of the species; and hence 
the space will be given to a discussion of those properties that are of the 
most importance in the approaching study of the rocks. The feldspars 
are all triclinic, with the exception of orthoclase, which is monoclinic, 
and hence easily distinguished from the others by its optical properties. 
Microcline, though not very evidently monoclinic in external form, is very 
plainly so in its inner structure, as will be shown. These two species 
stand isolated from the others, which are triclinic, and which all in com- 
mon are subjected to a peculiar method of twinning. This twinning is not 
the simple revolution of one part of a crystal about the other, but is what 
is called polysynthetic twinning, which consists in the repetition of this 
process so many times that a small crystal may consist of many hundred 
laminz, each one of which is revolved 180° from the position occupied 
by the neighboring one. To make the effect of this twinning plain, Fig. 
8 on Pl. 3 is introduced. Let the figure represent a section of a feldspar 
crystal cut parallel to the plane of the macro-pinnacoid, and suppose that 
an axis of elasticity makes some given angle with the vertical axis; then, 
if this section is placed between crossed Nicol prisms, it will be colored, 


MINERALOGY. 87 


except when the elasticity axis corresponds with the plane of vibration 
of the light, which is when the vertical axis makes a certain angle with 
this plane. But, suppose the crystal to be divided up into the laminz 
I, 2, 3, and No: 2 revolved 180° about an axis at right angles to the edge 
zz, and then No. 3 revolved in the same way about No. 2, bringing it into 
its original position again, as illustrated in Fig. 8a. It is plain that the 
effect of this, if often repeated, would be in the first place to cover the 
base O with striations running parallel to the edge of the brachy-pinna- 
coid, and to bring the axes of elasticity into such positions that, when 
they corresponded with the plane of vibration of the light in one set of 
the laminz, they would not in the other set in which they occupy the 
reversed position; and that in two consecutive lamine the axes of elas- 
ticity would make double the angle with one another that they do with 
the vertical axis of the crystal; and hence in polarized light the consec- 
utive laminze would be differently colored, and the section would appear 
banded. 

The extent to which the twinning may go on is illustrated in Fig. 6 
on Pl. 7, which is drawn from a basal section of a crystal of oligoclase 
from the Antrim granite. This section is so placed in the figure that 
one set of laminz is dark, which, in a basal section of oligoclase, happens 
when the plane of the laminze makes an angle of from three to four de- 
grees with the plane of the vibration of the light. A millimetre is placed 
in the figure for comparison, and it is seen that there are forty repetitions 
of the twinning in one millimetre, or over a thousand to one inch. The 
yellow crystal to the right is orthoclase. All triclinic feldspars have 
a basal cleavage; and, as the striation is there plainly shown, they 
are sometimes called striated feldspars. In polarized light, the effect of 
twinning would be seen in all sections save those parallel to the brachy- 
pinnacoid, which is the plane of the laminz. As the basal cleavage of 
feldspar is so easy, sections large enough for microscopic examinations 
are easily obtained from sizable crystals without labor; and mineralo- 
gists are thankful to Des Cloizeaux* for giving the position which the 
axes of elasticity bear to the brachy-diagonal axis of the crystals in 
basal sections of the different feldspars, and which furnishes a most 
ready way for their determination. 


* Des Cloizeaux Annales de Chemie et de Physique, 5th series, vol. iv, 1875, and vol. ix, 1876. 


88 MINERALOGY AND LITHOLOGY. 


It is of course plain that a basal cleavage piece of orthoclase, if put on 
the stage of the microscope between crossed Nicol prisms, would be 
dark when the straight edge formed by the meeting of the brachy-diag- 
onal and the basal cleavages was parallel to the plane of vibration of the 
light, since it is monoclinic. If a section of any other feldspar is obtained 
in the same way, and put between the crossed Nicols, it will appear as if 
made up of a series of bands parallel to the edge of the brachy-pinna- 
coid; and when these bands or this edge is placed parallel to the plane 
of vibration of the light, none of the bands will be dark, since no crys- 
tallographic and elasticity axes coincide in triclinic crystals; but, on 
turning a certain number of degrees to one side, a part of them will be 
dark, and, on turning the same, or nearly the same, to the other side, the 
rest will be dark, while the first become again brightly colored. The 
amount of the revolution necessary to produce these results varies with 
the different species, and furnishes the most ready way to discriminate 
between them. That is the angle that an elasticity axis makes with the 
brachy-diagonal can be determined, or the angle that the section must be 
revolved from the position, when one set of bands is dark, till the others 
become dark, (which would be just twice as much as the first angle, and 
is the angle between the elasticity axes in two parts of a twinned crystal) 
may be determined. These angles for the different species of feldspar, 
as fixed by Des Cloizeaux, are as follows: 


Angle between the Angle between the 
brachy-diagonal and elasticity axes in two 
elasticity axes. consecutive bands. 

Oliogoclase, : : ’ : r 2-4 4-8 
Labradorite, ‘ ; : : 5-7 10-14 
Albite, ‘ P a ‘ P ‘ 365-4 7-8 
Anorthite, . . ‘i 4 . . 27-37 54-74 
Microcline, c é 7 ‘ 5 15. 30. 


Fig. 6 on Pl. 7 may be taken as an illustration. It is drawn from a 
basal section of oligoclase from Antrim. In oligoclase a plane of elastic- 
ity cuts the base, making an angle of 3° with the brachydiagonal, and 
hence when these striz are placed parallel with the hair line indicating 
the plane of vibration of the light none of the striz are dark, but when 
the section is revolved three degrees one set of bands becomes black, 
while the other takes a higher color. If now the section be revolved 


MINERALOGY. 89 


from this position six degrees in the other direction, the other set will 
be dark and the first set bright colored. Hence this is oligoclase, since 
the elasticity and brachy-diagonal axes make an angle of 3° with one 
another in a basal section. Now since these angles are small, and the 
necessity of very close measurements is evident, the mere alternations 
of light and darkness furnish a rather crude method of measurement. 
It is plain that the calcite plate put between the ocular and upper Nicol 
would be of no assistance since the alternations of crystals in different 
positions would distort the interference cross of calcite, no matter how 
the crystal might be placed; hence the quartz plate which Mr. Rosen- 
busch places over the objective in the tube of the microscope, is here of 
the greatest value. This quartz plate produces circular polarization, and 
rotates the planes of vibration of the different colors to different degrees ; 
hence, by turning the upper Nicol we can intercept any given color that 
we desire. The violet color is thought by most workers to be the most 
delicate. If now we have the lower Nicol in its primary position with 
the plané of the light corresponding with one of the hair lines in the 
ocular, and the upper Nicol so placed as that the field of the microscope 
is a delicate violet, on interposing a section of a triclinic feldspar, one set 
of the bands of the feldspar will be of this violet color, when an elas- 
ticity axis in them corresponds with the plane of the vibration of the 
light, while the very slightest variation in the position will modify this 
color. Hence this microscopic method of measurement is very accurate, 
and gives a means with small basal cleavage splinters to determine the 
species of the feldspar. This method has been extensively used in the 
study on the composition of our rocks. 

It has been advanced as a theory that orthoclase, albite, and anorthite 
are the three well defined feldspars, and that all others may be derived 
from them by supposing them to be composed of a mixture of a certain 
definite number of molecules of these admitted species. These interme- 
diate species,—labradorite, andesite, and oligoclase,—have been classed 
together under the common term plagioclase, and the individual members 
of the group considered as subspecies. This is the theory advanced by 
Hunt and Tschermak, and which Des Cloizeaux’s determinations are 
regarded as disproving. It seems to be that careful measurements can 


with certainty determine to which species a feldspar, of which a basal 
VOL, Iv. 12 


gO MINERALOGY AND LITHOLOGY. 


section can be obtained, should be referred; and thus the species pos- 
sess sufficiently distinctive properties. But in fine-grained aggregates, 
where the nature of a feldspar can be only approximately determined, 
and where the difference between these kinds of feldspars is of no litho- 
logical importance, plagioclase is a good general term for use, and it has 
become so rooted in lithology that it is liable to maintain ‘its foothold, 
though perhaps in this modified sense. It seems that species of feldspar 
may grade into one another as other minerals do, where no theory is con- 
sidered necessary to account for it; so, as referring to a subgroup of the 
triclinic feldspars, it must be granted that the word plagioclase is con- 
venient, and in this sense it will be used. The three kinds of plagioclase 
will be treated of as distinct species whenever the composition of a feld- 
spar is known with certainty, and plagioclase will refer to imperfect or 
approximate determinations. The question, whether these three mem- 
bers of the plagioclase group should be merged into one mineralogical 
species, is of little practical importance, so long as the subject is so well 
understood as at present. 


57. ANORTHITE [Ca Al? Si? O*}. 


This kind of feldspar is a constituent of some of our diabase rocks and 
greenstones. It is contained in some of the calcareous diorites in the 
Connecticut valley, but the most notable specimens are found in the 
diabase at East Hanover. There a rock occurs that is filled with large 
crystals of this species. They are dull on their surfaces, but they pos- 
sess quite a number of planes, the prominent ones being the base, the 
domes 2%, 21, and the prismatic faces I and ii; and some edges are 
rounded off as if an effort were made to form other planes. These crys- 
tals are often an inch in length and breadth. Some are flat, and others, 
by a greater development of the prismatic planes, are thick and short. 
The rock is so full of them that it is an anorthite porphyry. 

These crystals are no less interesting because they have undergone an 
almost complete alteration. Before referring to this, it will be well to 
recall that anorthite is commonly subject to the polysynthetic twinning, 
which makes its base striated, and its sections, in polarized light, banded. 
A basal section, when placed between crossed Nicols, with its bands par- 
allel to the plane of vibration of the light, must be revolved through a 


MINERALOGY. gI 


much larger angle than any other feldspar, the angle for anorthite being 
from 27° to 37°, through which it must be turned in order to produce 
in either of its sets of laminze a maximum of darkness. 

If, now, a section of one of these fine anorthite crystals is cut, nothing 
of the kind is to be seen. The section placed between crossed Nicols 
appears made up of the most immense number of minute particles; the 
field is uniformly light; and, on revolving the section, no effect whatever 
is produced, and no point of maximum darkness is obtained. In other 
words, these crystals possess aggregate polarization, and are no longer 
feldspar; but the large crystal is made now of an immense number of 
little ones lying in every possible direction. I analyzed this feldspar pro- 
duct, with the following result : 


Anorthite. Typical 

Hanover. anorthite. 
Silica, . 5 ‘ ‘ ‘ ‘ 5 52.52 43.10 
Alumina, . % j 2 . ‘i é 30.05 36.90 
Iron sesquioxide, . A : : : 1.10 sesa 
Lime, ‘ ‘ ‘ F - 3 2.20 20. 
Magnesia, : é . . e F +30 
Potash, . é 2 5 é Fi . Ys S a ee 
Soda, ‘ A . é , ‘ js BG, a cape 
Water, . : : 3 ‘ F ‘ 207 i ai 

99-72 100.00 


Here is seen the progress of a change, which may result in the conver- 
sion of a basic into an acidic rock. Lime is removed, alkali is gained; 
and, while other minerals decompose, losing all their bases, and leaving 
residues of silica, here we see how this most basic feldspar is approach- 
ing to that composition, which, with the addition of some silica and a 
recrystallization, can form the orthoclase of our granites. 

Now, smaller crystals of this same feldspar in the rock are not so en- 
tirely decomposed ; and as the case is instructive, and the decomposition 
so prettily seen in progress, I add a drawing of a section of one of the 
crystals, which is seen in Fig. 3 on Pl. 5. The outside of the crystal is 
entirely altered into an aggregate, while within the fresh material shows 
the bands characteristic of triclinic feldspars. On revolving this section 
between crossed Nicols, the feldspar within shows alternations of color 
and darkness, and its optical properties can be determined, while the 


Q2 MINERALOGY AND LITHOLOGY. 


oustide of the crystal is always colored, and no optical property can be 
recognized, save those of an aggregate of minute needles. 

What the product of this decomposition is, is of minor interest. The 
change has resulted in the production of a substance of a higher specific 
gravity, the gravity of the specimen analyzed being 2.96, while that of 
anorthite is 2.75. It is the substance called saussurite. Hunt found this 
saussurite in some Swiss rocks to approach, in composition and gravity, 
to zoisite. It may be that this saussurite is one mineral or more, and it 
may vary in composition according to the degree of the change. A 
number of other names have been given to this product by different 
analysts. Saussurite is the best known term among lithologists, to whom 
the subject is of the most interest. 

Anorthite is often associated with labradorite in our basic rocks. 
When this is the case, the anorthite is usually in large crystals or grains, 
while the labradorite crystals are very small. The reason is, that the 
anorthite is much less fusible, and hence in rocks cooled from igneous 
fusion, the anorthite would crystallize first, and ‘would have an opportu- 
nity to form larger crystals in the still plastic mass. 


58. LasraporitE [ (Ca, Na?) AP Si? O"}. 


This is a feldspar of much importance in our state, for it is an ingre- 
dient of the larger part of our basic rocks. Its study is therefore one 
chiefly of lithological interest. 

On Mill mountain in Stark, very large masses of an apparently pure 
labradorite occur. It is an aggregate of crystals, but the microscopic 
sections bring to light such an amount of biotite and hornblende as to 
show that the rock is allied to the diorites. This is the most pure 
labradorite that we find. The rock is like one which occurs at Eden- 
ville, N. Y., and is allied to some of Hunt’s norites. 

Labradorite is subject to polysynthetic twinning. In basal sections, 
as already explained, it can be distinguished from other species, since 
a plane of elasticity cuts the base, making an angle of from five to seven 
degrees with the twinning plane. 

In the labradorite from Stark, the angle is five degrees to one side and 
six to the other, making eleven degrees between the point when one set 
of laminze is dark, and when the other set becomes dark. 


MINERALOGY. 93 


But triclinic feldspars, and labradorite in particular, are subject to 
another system of twinning. In this case the base is the common face, 
and the axis of revolution is a line lying in the base and at right angles 
to the edge between the brachy-pinnacoid and the base. The twinning is 
repeated, as in the first case. This produces striations on the brachy- 
pinnacoid, and bandings of color in sections cut parallel to that face, and 
which are parallel to the edge between that face and the base. If, now, 
a section be cut parallel to the macro-pinnacoid, between crossed Nicols, 
both these systems of twinning will be seen at once; and in the Stark 
labradorite this is often the case, as well as in all the labradorites that 
are to be spoken of. This double system of twinning is shown in Fig. 4 
on Pl. 5. Wide bands are shown which represent the laminze parallel to 
the brachy-pinnacoid, and in the laminz @ and 4 are seen cross bands 
that are parallel with the base, and which make nearly a right angle with 
the plane of the other bands (the inclination of the base on the brachy- 
pinnacoid being 93°), and hence in two consecutive bands these striae 
make a very obtuse angle with one another (174°). In feldspars that are 
more finely striated this inclination of the laminze to one another is not 
plain, and the same cross band seems to run through several lamina, 
giving a netted appearance to the crystals. 

The labradorite of the gabbros possesses peculiarities. It was first 
shown that the feldspar of the gabbros at Waterville and Mt. Washing- 
ton river is labradorite by Mr. Dana and Mr. Hunt, who analyzed that 
which is found at Waterville, while that found on Mt. Washington was 
analyzed by Mr. B. T. Blanpied, of Hanover. These analyses are as 


follows : 
Waterville (Dana*). Mt. Washington (Blanpiedf). 

Silica, . js ‘ a ‘ : 51.03 51.50 
Alumina, 5 - : : ° 26.20 25.90 
Iron sesquioxide, . 2 z a 4.96 5.00 
Lime, . 5 . ‘ ‘i - 14.16 14.29 
Soda, . 3 é 5 F - 3-44 2.95 
Potash, . é 2 : 3 ‘ -58 50 

100.37 100.14 


This feldspart is dark in color, and is covered with fine striations. 


* Am. ¥. Sc#., iii, vol. iii, p. 49. + Hitchcook's Ann. Rep. Geology N. H., 1871, p. 27. 
{This same feldspar was also analyzed by Dr. Hunt, with a result essentially the same. I have selected 
Dana’s analysis because it was first published. Hunt obtained SiO2 50.30, Al203 23.10, Fe203 4.23, MgO 2 95 
+95» 


94 MINERALOGY AND LITHOLOGY. 


The quantivalent ratio, in Mr. Dana’s analysis of the protoxides, sesqui- 
oxides, and silica, is as I: 3: 5.5, which indicates a trifle less silica than 
typical labradorite, the result being a little irregular, as remarked by 
Mr. Dana, on account of the presence of microscopic grains of a titanic 
magnetite, which with the greatest care could not be all separated. A 
glance at this labradorite in a thin section indicates the impossibility 
of obtaining pure material for analysis. The analysis of Mr. Blanpied 
agrees very closely with that of Mr. Dana, both showing a labradorite 
rich in lime, and containing the same impurities, as is confirmed by my 
microscopic sections. 

The microscope indicates in this feldspar a system of twinning like 
the labradorite of our other rocks, but the regularity and parallelism of 
the bandings are markedly absent. The feldspar is fresh and undecom- 
posed, and the bands receive the highest color in polarized light; but the 
individual striations are very narrow and often irregular, on account of 
the complex nature of the grain. The appearance of the feldspar is seen 
in Fig. 1 on Pl. 10. Among the microscopic impurities of this feldspar 
are olivine, biotite, and magnetite, but more interesting than these are 
the microscopic black needles that are represented in Fig. 5 on Pl. 5. 
The presence of these crystallites is very characteristic of the feldspars 
of gabbros; and they have been investigated by many observers, notably 
by Schrauf,* who studied the feldspar of gabbros from Labrador. He finds 
little plates, the nature of which he is unable to determine, inlaid in two 
planes parallel to the edge between the macro- and brachy-pinnacoids, 
but which are not planes occurring on labradorite crystals. The reflec- 
tions from these plates produce the aventurine effect of labradorite. 
These plates are not present in our feldspar, and hence it is not aven- 
turine; but the needles are sometimes present in multitudes, and most 
abundant in the centres of crystals. They are usually found inlaid par- 
allel to the basal and prismatic cleavages; but in our gabbro, it appears as 
though their arrangement were quite complex. This section in polarized 


CaO 14.07, soda and potash, 2.65—99.30. (Hitchcock's Ann. Rep., 1871, p. 27.) The quantivalent ratio of this 
analysis is as 1: 2.2: 4.6. This, which is a wide variation from labradorite, is explained by Dr. Hunt by the 
presence of biotite which he recognized, and it is true that the rock contains some biotite; but there is none of 
the rock which, under the microscope, is not seen to contain much chrysolite as an essential ingredient, and this, 
it seems to me from microscopic investigation, must be the main cause of the variation, since its presence would 
account for the variation very exactly, while the biotite is but sparingly present. 


* Wien, Akad., Ber., 1x, 996. 


MINERALOGY. 95 


light shows no bandings, and is consequently parallel to the brachy- 
pinnacoid, while a cleavage line indicates the direction of the base; 
hence we know the position of the crystal section. As is usual, it is 
plain from the figure that the most of these needles are parallel to the 
vertical axis, since they make an angle of 112° with the cleavage. Parallel 
to the base there are only a few, but those that lie in this direction are 
all notably very long. Both of these sets of needles are in the plane of 
the section or brachy-pinnacoid. There are, then, two more sets, making 
with one another a little more than a right angle, which is nearly 
bisected by the vertical. These needles are also numerous, but they do 
not lie in the plane of the section, but pass very obliquely through it, 
and hence lie in the plane of some octahedral faces, the angles of which 
cannot be ascertained on account of the obliquity. The needles are 
referred to augite by Schrauf. These structural directions indicate an 
interior development of these irregular grains, according to quite a com- 
plex crystalline form. 

The labradorite is often crystallized in the diabases, giving to them a 
pretty porphyritic character. These crystals are often quite noticeable, 
both from their form and the beauty of their sections. The feldspar 
of a somewhat decomposed gabbro from Waterville was analyzed by Mr. 
E. S. Dana,* with the following result : 


Silica, . ‘ 5 2 . 5 . ‘i : : . . 52.25 
Alumina, . ‘ F . 7 : z . : : ‘i : 27.51 
Tron sesquioxide, ‘ ° . 3 : ‘ ‘ 1.08 
Lime, . A ‘ . : . ‘i s . c ‘ 13.22 
Magnesia, a : 5 A . ‘ : . . 7 ° -99 
Soda, : F 3 . F . i : é ‘ - : 3-68 
Potash, . ‘ 3 . 3 a - ‘i . ‘5 5 2.18 

100.91 


The accession of potash and all the other characteristics of change are 
here seen, but only in an incipient form. A point of interest is remarked 
by Mr. Dana, that the New Hampshire labradorites are remarkable for 
their high percentages of lime. 


* Am, F¥. Sci., iii, vol. iii, p. 50. 


06 MINERALOGY AND LITHOLOGY. 


59. AnpEsITE [(Ca, Na’) Al’ Sit 0”). 


This is the feldspar intermediate in composition between labradorite 
and oligoclase. The necessity of its recognition as a species is question- 
able, since, chemically considered, the lines of its division from the two 
species mentioned are indistinct, and, optically, it cannot be distinguished 
from oligoclase. 

A feldspar occurs in the Dixville Notch, which is very noticeable on 
account of its very clear, glassy lustre, and its perfectly undecomposed 
appearance. It is found in the diorite, which by its decay has formed 
a bed through which a stream runs, and forms the Twin cascade,— 
one of our most beautiful falls. It gives the rock a remarkable appear- 
ance, for it is found in rounded pieces as large as walnuts, and the rock, 
when broken open, exhibiting these large, round, glassy spots, and large, 
black hornblende crystals, is quite striking in appearance. It would 
make a beautiful stone, if polished. This feldspar has a cleavage in two 
directions, as usual, though it often shows conchoidal fractures like quartz, 
which are deceptive. The crystals are twinned, but the separate laminze 
are broad, and there is, consequently, not such a fine striation as is com- 
mon in these species. My analysis of this feldspar from Dixville is as 


follows : 

Silica, . : : : ‘ - ‘ ‘ i ; x 2 56.24 
Alumina, . : 3 : : ‘ ‘ ‘ F 5 5 i 26.95 
Tron sesquioxide, . : é A A : : . ‘ é tr. 

Lime, ‘ * ‘ ‘ , ‘ ‘ ‘ i - és i 9-37 
Soda, ‘ : . ‘ e ‘ : 2 ‘ ‘ : ‘ 4-93 
Potash, . 5 F t : F : 3 F ‘ 5 ‘ 1.25 
Water, . 5 ‘i e . ‘ . - s 1.15 


99-89 

This analysis gives as a quantivalent ratio, 1:3:7, which shows it to be 
one of those varieties intermediate in composition between labradorite 
and oligoclase, and may be called andesite. A basal cleavage piece 
shows that an elasticity axis makes an angle of four degrees with the 
edge of the brachy-pinnacoid, which is an angle to which oligoclase some- 
times reaches. Its sections show that it is pierced with a few large 
apatite needles, not enough, however, to influence the analysis. 


MINERALOGY. 97 


This mineral shows very well the greater power which a pure, glassy 
feldspar possesses to resist decomposition, for it shows not the slightest 
change either in pieces or under the microscope. 


60. Oxicociasz [(Ca Na? K*) Al? Si® O"]. 


This, again, is an important and frequently occurring feldspar in our 
rocks. At Orange summit, specimens suitable for the cabinet are found, 
but its chief interest is lithological. The feldspars thus far considered 
are characteristic of basic rocks; but oligoclase being of a more acidic 
character, is often found with orthoclase in such rocks as granite, sienite, 
hornblende schist, and the like, and is more widely disseminated than 
was suspected before the microscope was brought to aid rock analysis. 
In thin sections of these rocks it is very easily distinguished from its 
associate orthoclase by its triclinic character, and its banded structure 
produced by twinning, which is so evident in polarized light. Some- 
times this mixture of orthoclase and oligoclase is macroscopically 
apparent, when the rock is coarse-grained in texture; for in such cases 
the feldspars are often of different shades of color, and the oligoclase 
can be distinguished by its greater tendency to alteration, which 
causes cleavage surfaces, where exposed, to appear duller than do those 
of the orthoclase; and though cases exactly the reverse have been 
observed by Zirkel and Rosenbusch, it may be regarded as the general 
rule. It may also be distinguished by the striations, which are some- 
times apparent, and which are superficially developed, sometimes by 
weathering, when they cannot be seen on fresh surfaces of rock. Their 
presence may be regarded as conclusive of the triclinic character of the 
feldspar, though their absence is not equally so. 

In sections of the rock the bands of color produced by a twinning 
are often extremely narrow, and the absence of superficial striation on 
oligoclase is perhaps often due to the extreme fineness of the lines. 
In Fig. 6 on Pl. 7, a basal section of a grain of oligoclase from the 
Antrim granite is shown. The bands of color are very thin, there being 
here a thousand to an inch, and they are also of extreme regularity, as is 
quite usual in the oligoclase of granites. The section is so placed in the 
drawing as that one set of laminze are dark, and the lamin make an 


angle of 3° with the spider line in the ocular. It must be turned 6° in 
VOL. IV. 13 


98 MINERALOGY AND LITHOLOGY. 


the other direction to make the other set dark. The yellow mineral to 
the right, without bands of color, is orthoclase. 


61. AuBiTE [Na? Al’ Sif O*}]. 


This feldspar is found in the great granite veins such as exist in Graf- 
ton, Acworth, Alstead, etc.; and in mining for mica very large amounts 
of it are extracted and thrown away. It occurs in tabular, white crystals 
belonging to the variety called clevelandite. It is whiter than the ortho- 
clase with which it is associated. It is often crystalline; and in places 
where the veins are cavernous, fine bright crystals of the ordinary form 
are found. The crystals are twinned according to the rule for triclinic 
feldspars. The optical properties of sections have already been given. 

Our albite from Alstead* was analyzed by Prof. J. D. Whitney, with 
the following. result : 


Silica, . F 5 - ‘ 5 3 ‘ ‘ 3 3 3 70.83 
Alumina, . 3 F 2 c 2 é ‘ e ' - , 21.20 
Soda and impurities, F ‘ ‘ a 4 s . ‘ . 7.97 

100.00 


Albite is not an important mineral in our crystalline rocks. G. Rose 
stated that albite was never present as a constituent of rocks. This has 
been shown to be otherwise. It does exist in small amounts in some of 
our granites, where it is associated with orthoclase and characterized 
by an excessively fine striation. 


62. OrtTHocLAsE [ K? Al Si’ OF]. 


This, the most common feldspar, is monoclinic. Its basal and brachy- 
diagonal cleavages make a right angle with one another, and basal sec- 
tions are consequently black between crossed Nicol prisms when the 
sharp edge formed by these two cleavages is parallel or perpendicular 
to the plane of vibration of the light. It is subject to twinning; but 
one crystal is rarely composed of more than two parts,—hence in the 
rocks it is never confounded with any other species of feldspar. 

The orthoclase of the most mineralogical interest is found in the mica 
quarries at Acworth, Grafton, etc., where very large crystals from eight 


* Geology of New Hampshire, Dr. C. T. Jackson, p. 178. 


MINERALOGY. ~ ‘ 99 


to ten inches in diameter are not uncommon. .The forms of the crys- 
tals are simple. They are rarely perfect, but their great size makes them 
interesting. The feldspar of these quarries is not economized, though 
similar veins in Connecticut, where the mica is of a poor and unmarket- 
able quality, are worked for the orthoclase alone. The feldspar is valu- 
able for the manufacture of porcelain. 

In our granitic rocks orthoclase forms crystals of considerable size, 
producing porphyritic rocks. In these cases the crystals are very com- 
monly twins, recognizable macroscopically as such by the different 
reflections of light from the two sides of the crystal, the cleavage faces 
of which are differently inclined. Crystals of orthoclase, freely devel- 
oped in cavities, are twinned according to one of four different methods; 
but ingrown crystals, with which we have mostly to deal, are almost 
always what are called Carlsbad twins. These twins are formed as if 
the crystal were divided in two by a plane parallel to the clino-pinna- 
coid, and then one half revolved 180° about an axis perpendicular to the 
ortho-pinnacoid, and the two parts united together again, or grown into 
one another. The clino-pinnacoid, by the large development of which 
ingrown crystals are commonly flattened, is therefore the composition 
face, but not the twinning plane. Examples of ingrown Baveno twins, 
though uncommon, are not unknown; and a crystal of this nature is 
represented in Fig. 4 on Pl. 10, and is described under the head of 
quartz porphyry. 

Orthoclase in granites, sienites, porphyries, etc., is white, flesh-colored, 
or red. In our oldest gneisses, its crystals are flattened and rounded, 
and surrounded by black mica, which gives them the appearance of eyes, 
from which these gneisses have gained the name of augen gneiss. The 
appearance of the porphyries is much modified by the color and lustre 
of the feldspar. They are light in color when it is white and opaque; it 
sometimes makes them red, and when the feldspar is colorless and trans- 
parent they are nearly black. The latter is the character of some of the 
porphyries about Albany, and these rocks, when held in a proper posi- 
tion, exhibit a beautiful play of colors that proceeds from the feldspar. 
This play of colors is most characteristic of labradorite; but in our state 
there is no labradorite that exhibits such a beautiful opalescence as this 
orthoclase. This rock, if polished, would make a most beautiful orna- 


I0Oo MINERALOGY AND LITHOLOGY. 


mental stone. These colors in orthoclase have been shown by Reusch 
to be due to a cleavage of extreme delicacy parallel to the plane of the 
clino-diagonal, producing interference colors like those of thin films. 

It is to be regretted that the various analyses that have been made on 
New Hampshire orthoclase have been unaccompanied by optical micro- 
scopic work, since triclinic feldspars are so often thus seen to be asso- 
ciated with it. Enough has been done to show, however, that our ortho- 
clase usually has a part of its potash replaced by soda. Jackson found 
this so in the orthoclase from the granite veins, which may be assumed 
to be pure. As typical of many analyses of the orthoclase of our rocks, 
the following by C. A. Seely, of a specimen from Bartlett, is selected: 


Silica, ‘j < : 3 : : : F ‘ ‘ 5 . 66.06 
Alumina, ‘ - f 3 ‘ 5 : ‘ , 3 20.04 
Tron oxide, F - 5 . ‘ A Re 5 3 : trace. 
Lime, - s . : is . - s Fi 2 7 2.08 
Soda, . : 4 3 é - . ‘ a ° : ‘ 7.28 
Potash, . . F . é tan . . fi ‘ : 5.47 

100.93 


Typical orthoclase contains silica, 64.6, alumina, 18.5, potash, 16.9. 
The analysis indicates the large replacement of the potash; and all the 
analyses that have been made show the same thing. Des Cloizeaux 
regards such analyses as indicating the existence of a soda feldspar 
isomorphous with orthoclase. 

In thin sections, orthoclase is commonly seen as grains which show 
more or less of an effort at crystallization. It is a fact of lithological 
importance that the fusible feldspar formed its crystals in these common 
acidic rocks before the infusible quartz did. At times these crystals are 
quite perfectly developed, and then they have the quadratic, rhombic, 
and hexagonal forms that would be expected from common crystals of 
orthoclase. In old rocks like ours, orthoclase usually appears more or 
less impure on account of the minute particles of foreign substances, and 
pores, and cleavage planes that exist in it. It often contains mineral 
enclosures, such as little. scales of mica, particles of hornblende, etc., 
but the rare occurrence of the cavities containing fluids, which are so 
uniformly present in the quartz, is very noticeable. Cavities often exist 
in it, but they are commonly empty, as is shown by their sharply defined 


MINERALOGY. 101 


outline. When examined with polarized light, twin crystals are most 
easily recognized, since the two parts are very differently colored, and 
stand sharply separated from one another. 

The microscopic study of the granites reveals some peculiarities of 
interest, one of which may be noticed here. Often a grain of feldspar is 
found which consists of laminze, or parts arranged at nearly right angles to 
one another. This subject has been discussed by many writers. Zirkel 
has shown that this effect is sometimes produced by the alternations of 
pure and impure orthoclase. Again: this is the characteristic structure 
of microcline which occurs interlaminated with orthoclase, as shown by 
Des Cloizeaux, and which will be considered beyond; moreover, it is a 
well known fact that orthoclase and albite are sometimes interlami- 
nated in this way. It is to such an interlamination that I now refer. 
Occasionally in the Concord granite, crystals of orthoclase are found 
which are quite impure and ingrown with them. They are very pure white 
crystals, which are arranged in two directions at right angles to one 
another, as shown in Fig. 6 on Pl. 5, and which in polarized light show the 
finest striations and the characters of albite. These crystals are arranged 
parallel and perpendicular to the clino-diagonal, since the optical deport- 
ment indicates that this section is nearly basal. I introduce this pretty 
cage so that such a kind of interpenetration may not be confounded with 
what follows. Rosenbusch has observed some effects of this kind. 

Another kind of interlamination of orthoclase is not uncommon in our 
rocks, which is illustrated in Fig. 1 on Pl. 8. This figure represents 
a crystal of orthoclase as it is commonly seen in the sections of granite 
from Chocorua mountain, when polarized light is employed. Each crystal 
is composed of a great number of irregular laminz, all having a com- 
mon direction, and which are invisible in ordinary light. The reason 
of this is, that the elasticity axes have a different position in one set 
of laminz than they do in the other, and the two sets, therefore, do 
not become dark between crossed Nicols at the same point ; but between 
the position in which one set of lamina becomes dark, and in which the 
other set becomes dark, there are a few degrees of difference. This 
causes the lamina to assume different colors in any position between 
the Nicols. This variability of the axes in monoclinic crystals is not at 
all uncommon. 


102 MINERALOGY AND LITHOLOGY. 


63. MicrociinE [K’ Al Sif QO”). 


Microcline is a feldspar of the same composition as orthoclase, but 
differs from it in being triclinic. Its position as a species has been fixed 
by Des Cloizeaux. The difference in the angle of its planes that deter- 
mines it to be triclinic is very slight, for the angle between the base and 
the clinopinnacoid varies but 16’ from a right angle,—a result obtained 
as the mean of many measurements. This difference is of course imper- 
ceptible to an ordinary observer; but the optical distinctions are so 
marked that its determination becomes very easy. As already explained, 
a basal section of orthoclase is black between crossed Nicols when the 
edge of the clino-pinnacoid is parallel to the plane of vibration of the 
light. If, now, a section of microcline is placed in the same position, it 
will be brightly colored, and will not be dark until it is revolved 15° from 
this position. This indicates that a plane of elasticity normal to the 
plane of the lateral axes cuts the base, making an angle with an axis,—a 
property of triclinic crystals. 

Microcline is most commonly green, forming what is called Amazon 
stone. At the Notch very pretty crystals of green orthoclase occur, and 
also a more massive variety. I have examined this feldspar, and, as might 
be anticipated, it proves to be microcline. As is the case with microcline 
in general, it possesses a complicated structure induced by twinning, 
which takes places in planes parallel and perpendicular to the clino-pinna- 
coid, and accompanied with this twinning there is also an interlamina- 
tion of orthoclase in the same planes. Therefore a basal section of our 
Amazon stone, when examined in polarized light, appears as made up of 
innumerable laminz running at right angles to one another. Its appear- 
ance between crossed Nicols is illustrated in Fig. 2 on Pl. 8, which is drawn 
from a section of this Notch microcline. It is placed in the figure in such 
a position that the edge of the brachy-pinnacoid is parallel to the plane 
of vibration of the light, as indicated by the lines. Now, in this position 
the orthoclase will be black like the field to the left, and it is plainly seen 
in bands of various lengths and breadths, while the larger part, being 
microcline, is highly colored, and one part of it becomes dark on turn- 
ing 15° to the right, and the rest, on turning the same amount to the left. 

Now in sections of our granites and gneisses, crystals with this struct- 


MINERALOGY, 103 


ure are not uncommon, and it is often possible to prove them to be micro- 
cline mixed with orthoclase. It is probable that they are always par- 
tially microcline. The Roxbury and Troy granites furnish examples in 
which quite large grains exist, which can be demonstrated to be micro- 
cline. Des Cloizeaux shows that albite is also commonly interlaminated in 
smaller or greater amounts, recognizable by the small angle at which, in 
albite, the extinction of light takes place between crossed Nicols. The 
green color of these crystals has been supposed to be due to the presence 
of a trace of copper, of protoxide of iron, and of organic matter. Analysis 
detects no copper, but a little heat destroys the color, which supports 
the idea that it is due to a minute amount of some organic substance. 


64. TouRMALINE [(K,? Na,’ H*) (Mg, Fe)? (Al,? B’)? Sit O”*'7]. 


Tourmaline is a very common mineral, and also offers some peculiar- 
ities in our state. It is hexagonal, and is found in three-sided prisms, 
which by the multiplication of prismatic faces, become sometimes nearly 
cylindrical. When well crystallized it is usually terminated by the three 
planes of the rhombohedron — ¢ R, or by a combination of this with other 
rhombohedrons. It is generally black; but light brown crystals are 
also found, which are more highly prized on account of their rarity, The 
great granitic veins are the most noteworthy localities, though tourma- 
lines are scattered through all the old schists, and are common in some 
granites. 

At Springfield very large crystals are found, which are quite unique 
from the extraordinary development of the basal plane. Fig. 3 on Pl. 3 
is drawn from one of them. The crystals, which are short and thick, and 
possess the planes represented in the figure, sometimes reach the great 
size of five inches in diameter, still maintaining their perfection and 
habit. They occur in the granitic veins. 

The best brown tourmalines are found at Orford, where they have crys- 
tallized in a bed of steatite, and often are of a large size. Crystals six 
inches long and two in diameter have been found, but more often it 
occurs in radiating masses of imperfect form. Brown tourmaline, in a 
‘massive condition, is found at Warren. 

Blue and green tourmaline, called indicolite, is found at Hinsdale, and 
also abundantly in a granite near Winchester. 


104 MINERALOGY AND LITHOLOGY. 


As localities that are of note for black tourmaline, may be noted Graf- 
ton (small, stellated forms of great beauty, and single fine crystals ; com- 
municated by Mr. A. Brown), Sullivan, Unity, Newington, Barrington, 
Bedford, Moosilauke mountain, Hinsdale, Chichester, Goshen, Lyme, 
Moultonborough, Saddleback mountain, White Mountain Notch (very 
large), Monadnock mountain, Surry, and Mt. Kearsarge. Pretty speci- 
mens, formed by needles of black tourmaline piercing white quartz, have 
been found at Hanover, Gilmanton, and Haverhill. A mineral, thought 
to be the kind of hornblende called bentonite, which is found at Leba- 
non, has been shown by Pisani of Paris to be bladed tourmaline. 

The finest tourmalines that are taken from the granitic veins, occur 
in quartz; but the mineral is also found associated with the feldspar and 
mica. When in the mica the crystals are usually flattened out into 
blades, and these blades are often so thin that they are translucent, and 
can be used as polarizers (see p. 85). I think that good specimens for 
the making of a polariscope could be obtained from Grafton. 

The difference of color in tourmalines is much dependent on the 
percentage of iron they contain, which is quite variable. The black 
tourmalines contain much iron, and the brown tourmalines, little. The 
composition of our tourmalines is well illustrated by the two following 
analyses made by Rammelsberg.* The first one is of brown tourmaline 
from Orford, and the second is of the black tourmaline from Unity: 


Silica, . a é 4 : : : a 38.33 36.29 
Boric acid, . 3 a ‘ 5 a 3 5 9.86 9.04 
Alumina, § 4 Fi 5 9 7 a : 33-15 30.44 
Iron protoxide, ‘ ‘ r - : 2.88 13.23 
Magnesia, : é 2 . F ‘ 3 ‘ 10.89 6.32 
Lime, . . . ‘ : x z 5 77. 1.02 
Soda and potash, . : . ‘ : : ; 1.52 1.94 
Water, . . 5 a 3 3 ‘ 3 2.81 1.72 

100,21 100.00 


These analyses agree with the formula given above; and the great dif- 
ference in the amounts of iron contained in the brown and black varieties 
will be noticed. The blue and green varieties, like those at Hinsdale, 


* Handbuch der Mineral Chemie, 1875, p. 541. 


MINERALOGY. 105 


usually contain some lithia, and are referred by Rammelsberg to a sec- 
ond division of the species. They contain no iron, and have a different 
general formula, the difference being mainly produced by a higher 
percentage of alumina. 

Beside the localities mentioned, tourmalines are abundant in many of 
our rocks in such quantities as to excite interest, though cabinet speci- 
mens are not common. For example: all through the White Mountains 
little tourmalines are seen here and there scattered through the schists. 
Sometimes they are very abundant, and of considerable size, and some- 
times they are very small and sparsely disseminated. 

The power which tourmalines possess to polarize light depends simply 
on the circumstance that the light only passes through the crystal par- 
allel to the vertical axis, the vibrations at right angles thereto being 
absorbed. This gives a most ready means for recognizing tourmalines 
in rock sections, since those sections which are cut parallel to the prism, 
when placed under the microscope with only the lower Nicol on the 
instrument, are light colored when the longer axis of the crystal is par- 
allel to the plane of vibration of the light, and almost black when placed 
at right angles to it. Basal sections must therefore be nearly opaque, 
and do not change on being revolved. Biotite, hornblende, and other 
dichroic minerals possess perfect cleavages, while tourmaline has none. 
Microscopic tourmalines are often seen in our rocks. 


65. ANDALUSITE [AI Si O*]. 


This silicate is very often found in our rocks. It crystallizes in square 
prisms of the orthorhombic system, which vary in size from microscopic 
bits to crystals an inch square. Their surfaces are never smooth, and 
their edges are usually rounded. At times, crystals or portions of crys- 
tals are pure, and possess a vitreous lustre ; but, on the other hand, 
andalusite is more common, which presents itself as a mere hard, irreg- 
ular spot in the rock, which becomes prominent on account of its greater 
ability to withstand the weather. Moreover, the centres and surfaces of 
the prisms often differ in their power of withstanding decay; and hence 
crystals are often found which have become hollow cylinders, a result of 
the rotting out of the centre. Again: both surface and centre resist 


while the rest gives way, and we then obtain a hollow cylinder with a 
VOL. IV. 14 


106 MINERALOGY AND LITHOLOGY. 


core. The crystals are ordinarily gray in their color, The White Moun- 
tain Notch, Boar’s Head (near Rye, in boulders), Charlestown, Troy, 
Rochester, Farmington, Mt. Kearsarge, Mt. Pequawket, Mt. Monadnock, 
and Andover, are a few localities where good crystals are found. 

The variety of andalusite called chiastolite is abundant in our state, 
and many rocks are beautified by the very pretty figures with which 
this mineral dots them. Sections across the ends of these crystals show 
crosses, squares, etc., due to the regular arrangement of impurities, which 
produce the black figures on a white ground, with which all are familiar. 
The microscope shows that these black portions are made by little black 
scales enclosed in the pure material, and, as a little heating destroys 
them, they are supposed to be coaly, bituminous matters. Chiastolite 
abounds on some parts of Mt. Washington, in Walpole, Albany, Alstead, 
Langdon, and Rye, and poorer specimens are found in many other places. 
Chiastolite is always found in argillitic rocks. 

If we obtain sections of crystals of andalusite we might suppose that 
they would exhibit the characters of an orthorhombic crystal, but this 
they rarely do. On revolving them between crossed Nicol prisms, no 
point of maximum darkness is found, but the field remains light all 
the time, and shows only the effects of aggregate polarization. This of 
course indicates an alteration of the crystal; and we have the material 
for observing its progress and result. Even the hardest and apparently 
most unaltered crystals under the microscope show alterations, as indi- 
cated by the multitudes of minute crystals which radiate from the cleav- 
ages. These cleavages are parallel to the faces of the primary prism, 
which has an angle of almost go°. These secondary crystals are made 
visible by polarized light, and cause the section to assume a most beau- 
tiful appearance when thus examined. Fig. 1 on PI. 6 represents a basal 
section of such a crystal, in which this incipient alteration is shown. It 
is of course impossible to indentify the mineral species into which the 
andalusite is here turning; but last summer Prof. Brush brought some 
andalusite crystals from New Preston, Conn., which he allowed me to 
cut. The inner structure of these crystals is illustrated in Fig. 2 on Pl, 
6. Here it is evident that a complete alteration of the crystalline ar- 
rangement has taken place, for the section figured is a basal one. None 
of these.crystals are dark between crossed Nicols when parallel with the 


MINERALOGY. 107 


plane of vibration of the light, which indicates that they are probably 
triclinic. The specific gravity of andalusite is 3.1, while the specific 
gravity of these altered crystals is 3.56, as proved by several determina- 
tions by Prof. Brush. My analysis of these crystals was as follows: 
Silica, 37.90, alumina, 62.12, water, .go— 100.92. Now all these charac- 
ters belong to cyanite, and demonstrate that a tendency exists in an- 
dalusite to alter the arrangement of its particles from the form of anda- 
lusite into the triclinic cyanite, which has a higher specific gravity, but 
the same chemical composition. The natural outer angles of these 
crystals are often much distorted by this change, and on examining a 
number of crystals wide variations were found in those angles that 
should be uniform. A still further process of alteration converts anda- 
lusite into mica, kaolin, etc., making it opaque and lustreless. There- 
fore the microscopic study of andalusite becomes a study of aggregates 
of other minerals. 


66. Fiprouite [Al Si 0%]. 


This mineral is the same in composition as andalusite, and differs from 
it only in the greater angle of its prism and the smaller angle of its optic 
axes, neither of which is a consideration with which we can deal, since 
it is only found in fibres in the schistose rocks. That it really has some 
specific difference is evident from the circumstance that it does not de- 
compose as does andalusite, but, although in small crystals, is usually 
clear and fresh. 

Fibrolite exists in some of the schists of the White Mountains in such 
amounts as to give a character to the rock. In thin sections it is recog- 
nized as orthorhombic, by noting that the fibres all become black when 
they are parallel to the plane of vibration of either one of the crossed 
Nicols. The interference colors that are obtained when it is in any other 
position are very bright. In Fig. 3 on Pl. 8 a section of fibrolite schist 
from the Notch is represented. The fibrolite pierces the biotite and the 
quartz in such a way that it is plain it was the mineral first formed in 
this schist, with the exception of the little magnetite grains, a few of 
which are included in the fibrolite. Winchester is another locality where 
fibrolite abounds. 


108 MINERALOGY AND LITHOLOGY. 


67. CyaniTE [Al, Si O5]. 


The ordinary blue, bladed crystals of this mineral abound in many 
localities in our state. They are conspicuous, and easily recognized. 
These blades are made by the meeting of prismatic planes, which make 
an angle with one another of 106°, and which are also the cleavage 
planes; hence, in thin sections of the rocks, cyanite, when cut parallel to 
the base, appears as composed of many little rhombs. In thin sections it 
can easily be recognized as triclinic, since none of its sections are dark 
when the prism is parallel with the plane of a Nicol. This can also be 
tried with cleavage bits, that are so easily obtained ; but it is to be noted, 
that unless they are very thin, no result is obtained, since the large crys- 
tals are so often composed of little crystals in twinned positions that the 
splinters, if not very thin, are always colored when revolved between the 
Nicol prisms. Bellows Falls, Lyme (in the north-west part), Jaffrey (Mt. 
Monadnock), Orford, Warren, Hanover, and Norwich, Vt. are places 
where good specimens of cyanite can be obtained. 


68. TITANITE (SPHENE) [Ca Ti Si O°]. 


This is not of much mineralogical interest, save as a rock constituent, 
in which condition it is widely distributed, though rarely visible except 
with the microscope. It commonly presents itself in rounded grains, but 
sometimes the rhombic and six- or eight-sided forms, which are obtained 
by cutting its common crystals, are seen. The sections are usually 
greenish-yellow and dichroic, but, owing to the faintness of its color in 
thin sections, it is not always possible to observe this. In color and 
dichroism it looks like epidote, from which it is easily distinguished, 
because, between crossed Nicols it gives scarcely any colors, while epi- 
dote gives very brilliant interference colors. 

In our rocks titanite appears usually to be a product resulting from 
the decomposition of titanic iron. For example: it has been explained 
that the titanic iron in our greenstones is often subjected to a peculiar 
kind of decomposition. Now, where the skeletons of titanic iron are 
most abundant, there the sphene is found in the largest amounts. As 
was stated, the iron of titanic iron being removed, the product remaining 
has been shown by Prof. Lasaulx to be titanate of lime, but, if silica takes 


MINERALOGY. 109 


part in the reaction, sphene is formed. The diorites and amphibolites 
about Littleton are rocks in which sphene is common. 

Again: on the road from the Glen house to the top of Mt. Washing- 
ton, some large dykes of diabase occur. They are full of titanic iron. 
Now, on the junction of these dykes with the surrounding rock, a thick 
layer of a very ferruginous chlorite occurs, which is a product of the 
decomposition of the trap. This chlorite is filled with crystals of sphene. 
This association of minerals is common, and perhaps may often be ex- 
plained in this way. 


69. STAUROLITE [H? (Mg, Fe)? Al” Sif O*]. 


Staurolite is very common in our slaty rocks. Here as elsewhere it 
is found in the twin crystals, from which it derives its name. The crys- 
tals cross one another at right angles when the twinning plane is the 
prismatic one, and at 120° when the plane is octahedral. The crystals 
vary in color from light to dark brown, and, though sometimes nearly 
transparent, are often well-nigh opaque from the presence of impuri- 
ties. Staurolite is abundant in the mica slates about Lisbon, and at 
Mink pond in that neighborhood they are found loose in the soil, having 
been washed out of the decomposing rock. Large brown crystals occur 
at Franconia, and very large crystals at Charlestown. Mt. Washington, 
Grantham, Bellows Falls, Walpole, Enfield, and West river, Vt., are 
localities that are notable for staurolite, though they are found all along 
the Connecticut valley. It is very often associated with garnet. 

Though the chemical composition of some varieties of staurolite cor- 
responds to the formula given, it varies greatly, as is shown by the two 
following analyses of staurolite from our state by Rammelsberg.* The 
first is of a brown crystal from Franconia, and the second of one of the 
clear deep brown crystals from Lisbon. 


Sp. Gr. 3.76 Sp. Gr. 3.42 

Franconia. isbon. 
Silica, 7 ‘ 7 . ‘ ‘ é ‘ 35.36 49.10 
Alumina, . : ‘ : i 3 2 : 48.67 37-70 
Iron sesquioxide, . @ c ‘ - ‘ . 2:27 sichsne 
Iron protoxide, . : : . 2 c z 13.05 10.69 


* Mineral Chemie, p. 590. 


IIo MINERALOGY AND LITHOLOGY. 


Magnesia, : : - ‘| i z 7 e 2.19 1.64 
Ignition, ‘ 3 é e ‘ a 27 -68 
101.81 99.81 


This very great difference in the two analyses is explained by the cir- 
cumstance that the staurolite with a high percentage of silica is rendered 
impure by the enclosure of quartz, as has been proved by a number of 
investigators; and these irregular varieties, when purified from the quartz 
by treatment with hydrofluoric acid, as was done by Rammelsberg, give, 
on analysis, a composition which corresponds also with the formula. 
This admixture of quartz is apparent in the specific gravity which sinks 
from 3.76 in the purer variety from Franconia to 3.41 in the impure 
variety from Lisbon. Sections of the Lisbon staurolite show the quartz, 
which is present as large clear grains scattered through the interior of 
the crystal. 

Staurolite forms macles, or tessellated crystals like andalusite ; but this 
is a rare occurrence, and I am not aware of such having been observed 
save those noticed by Jackson at Charlestown, in our state. These ma- 
cles of staurolite are made in the same manner as the andalusite macles 
by the symmetrical arrangement of pure and impure material. Fig. 8 on 
Pl. 2 represents the base of one of these crystals. They are found in 
the mica slate, which Jackson states gradually passes into an argillite, 
and with it the character of the crystals changes till they become anda- 
lusite macles in the argillite. 

This staurolite is not in twin crystals; a rare occurrence, since stau- 
rolites which are apparently simple usually prove to be compound when 
cut and examined. These peculiar macles have been examined by Peters 
and Rosenbusch, and by Jackson. Fig. 8 is taken from Jackson's article. 
Fig. 8a is from Rosenbusch’s Mzkroscopische Physiographie, by which it 
is shown that the macle is not produced by twinning, since the cleavage 
lines are undisturbed, but that the case is one where a core is surrounded 
by another crystal, giving to the whole a laminated structure, and the 
macle results from the regular arrangement of impurities and cavities, 
which are most abundant between the outer and the inner crystal. 

The microscopic characters of minute crystals are usually the same 
as those of the large ones. In them more or less quartz is found, and 
apparently simple crystals, with polarized light, are seen to be twins; 


MINERALOGY. It! 


but when staurolite sinks to microscopic proportions in the slate rocks 
of the Connecticut valley, it shows what is rarely seen,—really simple 
crystals. The color of this microscopic staurolite is deep brown. It is 
highly dichroic, and if its sections are revolved over one Nicol, when the 
long axis of a crystal is parallel to its plane, the crystals are deep brown, 
and when at right angles thereto, they are nearly white. The crystals 
are extremely impure. They possess no terminations; but the direction 
of the prism is indicated by their fibrous character, and they are recog- 
nized as orthorhombic, since between crossed Nicols the maximum 
extinction of the light in all sections takes place when this striation is 
parallel to the plane of one Nicol. Basal sections do not show the stria- 
tions, but are still dichroic (distinction from biotite), and show some very 
rude attempts at the formation of a six-sided figure, which is more 
often nearly round. None of these microscopic crystals aretwins. They 
might at first be mistaken for biotite, but not after a moment’s examina- 
tion. The appearance of this common staurolite is given in Fig. 4 on 
Pl. 8. It is drawn as it appears when the lower Nicol is on the instrument, 
and the plane of the light is indicated by the arrow. The excessive 
impurity of the staurolite will be noted; but this character is much more 
evident when both Nicols are upon the instrument. This figure is intro- 
duced as explanatory of the analysis with the high percentage of silica, 
and also as showing a deceptive, simple form into which staurolite sinks 
in our rocks. 


Hyprovus SILICATES. 


New Hampshire, which, as is well known, is mostly occupied by gran- 
ite hills and old crystalline rocks, is mostly composed of anhydrous sili- 
cates, and, as might be expected, is poor in the hydrous species, for there 
has not been the opportunity here for their formation. The great trap 
dykes of the Mesozoic, which have proved to be so rich in these species, 
come only to our boundaries; and, though trap dykes are abundant in 
our state, they are not large, are rarely amygdaloidal, and do not offer 
conditions favorable to the formation of minerals from their decompo- 
sition: hence our list of hydrous silicates is small in comparison with 
the number of species described. Those which occur in any abundance 
belong to the foliated micaceous margarophyllites, 


112 MINERALOGY AND LITHOLOGY. 


40. PREHNITE [H? Ca? Al? Si? OF]. 


This mineral is found at Bellows Falls, and also at Franconia. It isa 
green mineral, orthorhombic in form, which results from the alteration 
and decomposition of other minerals, especially of the basic minerals of 
trap rocks. It is inconspicuous in our state. It is found only in thin 
crusts, which appear almost amorphous, being aggregates of so many 
small crystals. 

71. AnatciTE [Na’ Al? Sit O8 +. 2H? O}. 


I am aware of only one occurrence of this mineral, and that a micro- 
scopic one, which presents the usual optical peculiarities of this species. 
Some of the augite porphyry at Campton falls is filled with little micro- 
scopic cavities. These cavities are represented in Fig. 3 on Pl.6. The 
walls of all these cavities were first coated with a yellow, formless, drusy 
mineral called sphzerosiderite, a carbonate of lime and iron. Then there 
was a growth of hexagonal calcite crystals, terminated in some cases by 
the planes of an obtuse rhombohedron, and sometimes extending entirely 
across the cavity; and, lastly, the remaining room in the cavities was 
entirely filled with analcite. This analcite shows a quite fine cubic cleav- 
age, a thing not often macroscopically seen in such perfection. Analcite 
is isometric. Isometric crystals are black between crossed Nicols, and 
act like amorphous bodies, but this analcite does not so behave. Some 
few of its sections are black; but the larger part are dark only in certain 
positions, and on revolving them they assume a bluish-black color, be- 
come sensibly lighter in shade, and become black again when they have 
been revolved 90°, and thus, though faintly, they show all the peculiar- 
ities of prismatic crystals. This deportment has caused serious doubts 
to be thrown upon the isometric character of analcite; and leucite, 
which crystallizes like analcite, and shows the same peculiarities in a 
somewhat more marked degree, is quite satisfactorily proved to be tetrag- 
onal. The anomalies of analcite were first noticed by Brewster; and 
Des Cloizeaux subsequently determined that sections cut parallel to any 
of the cubic faces act in parallel polarized light like isometric crystals,— 
that is, light passing parallel to any axis is not modified. Analcite, 
which like this entirely fills cavities, has been noticed in several basaltic 
rocks, chiefly Italian. 


MINERALOGY, 113 


72. Tarc [H? Mg? Sit O”]. 


Talc, as it occurs in New Hampshire, is chiefly of the variety called 
steatite, or soapstone, of which we have large beds that have been exten- 
sively worked. At Francestown there is a large quarry where talc of ex- 
ceptional purity has been mined since 1802. At Orford there are five 
beds, but the mineral is of a slaty character, and not so easily worked. 
At Richmond the beds are still more impure, and the mineral con- 
tains anthophyllite and pyrites, which interfere with the sawing of it 
into blocks. Keene, Weare, Warner, Canterbury, and Lancaster are 
other localities where steatite has been found. The impure varieties 
are of economic value, though they may not be transported to markets 
at adistance. At Haverhill a large bed of steatite was long ago found, 
and very large boulders of soapstone are found at Pelham, which have 
been transported from some unknown locality. At Norwich Vt., the 
pretty green foliated variety of talc has been found. 

Talc is not found with well formed crystal faces, but it is considered 
orthorhombic, and its microscopic characters correspond to those of such 
crystals. The steatite in thin sections appears to be a fibrous mass, and 
where the fibres do not overlie one another so as to interfere with one 
another, the fibres are dark when parallel to the plane of vibration of the 
light. If we take one of the folize of the nice green talc from Norwich, 
and put it under the microscope, take out the ocular and cross the Nicols, 
we shall see a black cross which opens out into two hyperbolas as the 
section is revolved, and which shows the biaxial character of the crystal, 
and that the optic axial angle is not large (17°-19° in the air). These 
characters agree with those belonging to talc, in which the cleavage is 
basal, the bisectrix normal to the base, and the optic axes in the plane of 
the macrodiagonal. 

Tale is a constituent of some of our rocks. In thin sections of them 
it is usually in radiated masses. It is distinguished from chlorite in that 
it shows neither dichroism nor absorption of light, and is usually fresh 
and undecomposed. 

Tale enters into some granitic rocks, forming protogene, and with 
some accessories forms the stratified talc schist. Much of the so-called 


talcoid schist of Vermont and New Hampshire was shown by Prof. G. F. 
VOL. IV. 15 


II4 MINERALOGY AND LITHOLOGY. 


Barker to be argillitic mica schist, since on analysis the specimens yielded 
no magnesia. They were supposed to be talcoid because they had a 
soft-soapy feel, and an appearance of talc. These schists are widely 
distributed, while the talc schists are much more local occurrences. 


43. SERPENTINE [Mg? Si? O" +2 H? O] 


Serpentine is not a common mineral in our state. It is found in small 
amounts in some chloritic rocks of the Connecticut valley, and Mr. Hunt- 
ington has observed it at Pittsburg. It is found in light green granular 
layers or aggregations, which are either interstratified in the rocks, or scat- 
tered irregularly through them. Again: in some of the trap rocks, serpen- 
tine is a microscopic product which results from the alteration of olivine. 
As serpentine, wherever found, has the microscopic appearance of being a 
product of alteration, so, in thin sections, it has not the properties of an 
original crystal, but its optical behavior is that of an aggregate. It gives 
bright colors when revolved between crossed Nicols, but shows no other 
crystalline characters. Its microscopic appearances are various, and de- 
pend much on the mineral from which it is derived; but no extensive 
material for its study is offered in our state. 


74. Kaotin AND Ciay [AP Si? O7 -+ 2H? O]. 


Products going under these names abound all over the state. Kaolin 
is the mineral species to which they must be referred, although in a pure 
state it is not common. Kaolin is formed in all granitic regions by the 
decomposition of feldspar. In the Southern States, below the limit of 
glacial action, where the resultant products have often remained in place, 
there exist immense beds of soft rock composed essentially of quartz and 
kaolin; but in our section, where the glaciers broke down and removed 
all such decomposed materials, the kaolin is found in the lowlands mixed 
with pulverized quartz, forming the clay beds. Under the microscope, 
the composite nature of clay becomes very evident, yet the kaolin is 
often seen to be in minute crystalline scales. This crystalline character 
of the kaolin of clays was first pointed out by S. W. Johnson and Blake. 
Kaolin is orthorhombic. That the particles are crystalline is easiest 
seen by noting that they are double-refracting, and give colors between 
crossed Nicols. Besides quartz, our clays contain ferruginous materials, 


MINERALOGY, 115 


which cause the bricks made from them to burn red. At times they 
contain much lime, when they are called marl. 

Kaolin, when pure, is white, and often flaky. When clay is consoli- 
dated, it forms beds of argillite, and this is the first stage in metamor- 
phism. The beginning of the change is marked by the production of 
an imperfect schistose structure, a loss of a part of the water and of the 
soapy feel. 

Clays are not merely variable on account of their composite nature; 
but a large number of apparently pure and homogeneous products have 
been analyzed, and a number of species established as the result. Amor- 
phous clay-like products, very different in appearance and physical prop- 
erties, are found. They are, as a rule, kaolin in different states of con- 
solidation, but one most peculiar product, called mountain cork, is found 
at Franconia. It is extremely light, though apparently firm and com- 
pact. It is made of the finest microscopic fibres, so interlaced as to 
make the mass very tough and hard to tear, though it cuts with a knife 
like cork. It floats lightly on water, but it rapidly absorbs water, and 
then sinks. Its weight is about equal to that of cork, and its whole 
appearance immediately suggests the name by which it goes. Similar 
products to this, and which are called by the same name, are composed 
of hornblende; but this substance, which I have analyzed, and which 
was furnished to Prof. Brush by Mr. Pierce, of Providence, who obtained 
it from our state, gave as the result of analysis,— 


Silica, . 7 7 : 3 . i c 3 7 : : 58.15 
Alumina, : ‘ . - . z : r 2 " 13.20 
Magnesia, é 3 5 F . . 5 7 : ‘ : 9.75 
Water, . r : 7 r 3 . : * : 5 r 18.68 

99-78 


The same product was analyzed by Mr. Calder, of Providence, and his 
results were not widely different from mine; but every new analysis that 
he made gave him new results. Hence, as no two analyses can be 
made to agree, it is plain that the substance is not homogeneous, and 
that it is merely a hydrated and altered asbestus (hornblende). It fuses 
without difficulty before the blow-pipe, and its composition is such as to 
make this conclusion tolerably certain. This product has excited consid- 


116 MINERALOGY AND LITHOLOGY. 


erable interest. What the mineral is now cannot be said with certainty, 
since it is not homogeneous. It has at least got quite near in composi- 
tion to some of the kinds of clays. It occurs chiefly in cavities of the 
slaty rocks. 

45. PINITE. 

Under the head of pinite, a number of amorphous products are classed 
together by Prof. Dana, which are essentially hydrous silicates of alumina 
and potash, and which have resulted from the decomposition of alkaline 
silicates. A green substance, which has been referred to pinite, occurs 
in the granites of Bellows Falls, and in the protogene rocks at Littleton 
and other places in the neighborhood. These substances, when examined 
in thin sections under the microscope, resemble serpentine, a mineral to 
which, in its mode of origin, pinite is closely related. 


46. MARGARODITE—SERICITE. 


Muscovite, as is well known, is exceedingly subject to hydration, and 
while yet maintaining its physical and optical properties, gives, on analy- 
sis, considerable water. This change is evinced in an increase of pearly 
lustre and opacity, but in other characters it is still like muscovite. A 
large amount of the mica in our rocks is more or less hydrous, and may 
be called margarodite, if one so choose; but in the study of lithology 
there is a stage beyond this, where a hydrous mineral, nearly related to 
these in composition, has none of the characters of muscovite, and is a 
fibrous mineral resembling talc, from which it is distinguished by its 
composition. This mineral was called sericite by List, on account of its 
silky lustre; and the rocks containing it have been called sericite schist, 
gneiss, etc. Rosenbusch believes that sericite is a well established spe- 
cies, thoroughly distinguished from micas by its fibrous structure, while 
Lasaulx regards this subject as needing investigation, and thinks that 
various micaceous minerals are included under the name sericite. Prof. 
Dana calls these rocks, which contain this soapy, talc-like mineral, hydro- 
mica schist; and although, while the question ‘stands as to-day, 'this is 
the best name, yet it may be stated that we ‘have in our ‘rocks, first, a 
hydrous mica with a micaceous structure, and with the optical properties 
of muscovite. It is usually yellow in thin sections, and shows the cleav- 
age very distinctly. Again: we have in other rocks a fibrous mineral 


MINERALOGY, 117 


which bears no resemblance to mica, which, however, is certainly related 
to it in composition, which looks in the microscope like talc, and gives 
its character to the rocks, and is what has been called sericite. Such 
rocks occur at Northumberland, and at various points on the Connecticut. 
Lasaulx shows this mineral to be a product of the decomposition of feld- 
spar in some cases. 

In regard to margarodite, it may be noted that a visit to our mica 
mines shows how quickly muscovite is turned to margarodite, after a lit- 
tle exposure. The mica that is rejected, and thrown into piles on one 
side, very quickly becomes hydrous, loses its transparency, and becomes 
silvery. A piece exposed less than a year gave me 4.2 per cent. of water ; 
and hence we might expect that the mica, wherever exposed, would be 
hydrous. 

A hydrous mica is found at Enfield, associated with quartz, which 
forms rounded mammillary forms, composed of excessively minute scales. 
The whole appearance of the mica resembles prehnite, but it is nearly 
infusible, and close examination reveals its micaceous structure. I 
have examined this mica, and have found it to be a soda-potash mica, 
intermediate between margarodite and paragonite. It resembles one 
analyzed by Smith and Brush, from Litchfield, Conn.* The specimens 
examined were furnished by Mr. Downs. These intermediate species 
between the hydrous, potash, and soda micas, indicate that the dividing 
lines between them are indefinite. 


CHLORITE. 


Under this head it is proposed to describe those minerals which, 
though having essential chemical differences, yet have those well known 
‘properties in common that cause them to be all usually-called chlorite. 
The chlorites are hydrous silicates of magnesia, iron protoxide, and 
alumina; their hardness varies between that of talc and gypsum; they 
are foliated like mica, but their folize are not elastic as are those of mica; 
and they are of various shades of green, according to the amount of iron 
which they contain. The three most common species of chlorite are the 
monoclinic ripidolite, the rhombohedral -penninite, and the hexagonal 
prochlorite. The first is biaxial, the second and third uniaxial, though 


* See “‘ Margarodite,’”” Dana’s Mineralogy. 


118 MINERALOGY AND LITHOLOGY. 


the latter species has often a slight angle between its two optic axes. 
Chlorite forms large aggregations which might be termed rocks, and 
besides its occurrence in what would be termed mineral specimens, it is . 
an essential constituent of chlorite schist, diabase, &c. The particular 
species of a chlorite which exists in a chlorite schist is often hard to 
determine, and the more so because more than one species are liable 
to be present together. For example: in some schists there are basal sec- 
tions of chlorite which remain dark between crossed Nicol prisms during 
a whole revolution (hexagonal), while others, in position likewise parallel 
to the cleavage or base, do not remain dark, and are therefore biaxial. 
The name viridite is reserved for those green chloritic products which 
can be referred to no species, which cannot be isolated for examination, 
and in reference to which it only is known that their appearance and 
association indicate them to be chlorites. The chlorites are usually 
dichroic, with the exception of the viridite which acts at times like an 
amorphous substance. 

Besides its occurrence in the rocks, chlorite is found often in radiated 
and foliated aggregations, in cavities and clefts. The process of hydra- 
tion and alteration of basic rocks usually gives rise to the formation of 
more or less chlorite. The following species have been determined in 
our state. 


77. RipipoLirE (Monocuinic) [Mg’ AP Si? O"% + 4H?O}]. 


This is probably the chlorite that is most abundant in the chlorite 
schists. It is also found in the beds of talc and talc schist, and it occurs 
in well formed crystals at Orford. It is bright green in its color, but 
strongly dichroic, being green in the direction of the vertical axis, while 
it is brown or yellow in a transverse direction. This is best observed in 
thin sections under the microscope. In these sections, as a rule, no 
crystalline form can be noted, but all the sections are double-refracting. 
This chlorite occurs in rocks that do not contain large percentages of 
iron, and do contain considerable magnesia. It may be an original 
product, and it may be the result of the alteration of other minerals. 
Between crossed Nicols it gives brilliant interference colors, and is 
usually more or less impure from the presence of magnetite. 


MINERALOGY. 119 


48. PENNINITE. 


To penninite are referred those little hexagonal plates of chlorite that 
‘are sometimes found in the chlorite schists, and which have the optical 
properties of an uniaxial crystal. No chlorite of this form and composi- 
tion has been found in condition for analysis, and it is hence only to be 
borne in mind as being a probable constituent of our chlorite rocks. 

Quite different, now, are those chlorites that are so abundant in basic 
rocks, being usually products of the decomposition of ferruginous min- 
erals. One of the best determined of these minerals is,— 


79. PROCHLORITE [H® (Fe, Mg)” Al® Sif O”]. 


This is a chlorite of an uncertain crystalline form, though often found 
in hexagonal plates. It is not strictly uniaxial, however, and its optical 
properties do not appear to be those of an hexagonal mineral. Itisa 
magnesia iron chlorite, which, according to Rammelsberg, has an atomic 
ratio between the protoxide elements, the alumina (Al,) and silica of 3.3: 
1:2 as the mean of many analyses. 

On the road from the Glen house to the top of Mt. Washington there 
are some large trap dykes; and between these dykes and the surround- 
ing rocks is a layer, six inches or more in thickness, of a pure crystallized 
chlorite, which forms a selvage. It gave me, on analysis,— 


Silica, z ‘ a a : ‘ : : 5 2 2 25.32 
Alumina, . . . : . ; . : B : : 20.94 
Iron sesquioxide, . : ‘ : . s 3 . . : 1.94 
Iron protoxide, ‘ ‘ < . - c ‘ i 5 F 26.71 
Manganese protoxide,_. c 5 . : . a +20 
Magnesia, . é : : , ‘ : A ‘ j z 14.05 
Water, . F ; z 3 a F . ‘ , j 9-90 

99-06 


It is remarkable how very closely this analysis approaches to the atomic 
ratio adduced for prochlorite, which proves conclusively that it is that 
mineral. 

This chlorite is very deep green, and in thin sections is dichroic, though 
not so strongly so as some other chlorites. Under the microscope it 
appears unusually pure, its only inclusion being crystals of sphene. In 


120 MINERALOGY AND LITHOLOGY. 


microscopic sections it is seen to possess a concentric radial structure. 
This structure is wholly microscopic, for, although chlorite is noted for 
assuming fan shapes, no arrangement of the kind is macroscopically vis- 
ible. This chlorite was evidently formed from the products of the de- 


composition of the rock. 
So. ViripiTE, DELEsSITE, DIABANTITE. 


When now we come to consider what is the chlorite that is formed in 
the basic rocks themselves, the investigations are quite conflicting. It is 
known that in almost all the old basic eruptive rocks, much chlorite has 
been formed at the expense of the augitic and hornblendic constituents, 
and the nature of this chlorite has been studied by many mineralogists. 
It is well known that these are chlorites which contain much iron, and 
are liable to give the most variable formulze on account of the ready oxi- 
dation of this iron. Delessite is probably the name by which they are 
best known, but Kengott would refer them all to the species last de- 
scribed (the ripidolite of G. Rose). The formula of delessite could never 
be fixed because the analyses were so various. Liebe came very near 
it, and from the mean of several analyses deduced a formula, and named 
the mineral diabantachronyn, because it was the coloring mineral of dia- 
base. I obtained this chlorite in a very pure state from the diabase near 
New Haven, and got an analysis which seemed to me must be pretty 
near the original composition of this chlorite, since the iron was essen- 
tially all protoxide. The analysis confirmed Liebe’s results, and so I 
took the name he had given it, only shortening it to diabantite. The 
analysis was as follows: SiO 33.68, Al,O; 10.84, Fe,O 2.86, FeO 24.33, 
CaO .73, Mg O 16.32, water 10.02.* The quantivalent ratio of its bases 
and silica are as 1:1, while in the prochlorite, the analysis of which is 
given, they are as 3:2, and the formula of diabantite, as drawn from the 
analysis, is (Fe, Mg)” (AP, Fe’)? Si? H® O*. The exact equivalence of 
the elements, its undecomposed appearance, and all its characteristics, 
indicate that this is very likely the chlorite of diabases, and that delessite 
is likely the same thing in an impure condition. It may at least answer 
the purpose of this study to assume that we know the approximate com- 
position of the chlorite of diabase, and that it is certainly near that indi- 


* American Fournal of Science, iii, vol. ix, p. 455. 


MINERALOGY. 121 


cated by the analysis given above. As observed in thin sections, this 
chlorite, which is formed by the decomposition of basaltic, ferruginous 
minerals, often refracts the light so as to give the brightest colors between 
crossed Nicols, and often it is seen as an aggregate of fine scales; and, 
again, a green, ferruginous chloritic substance is often found in such 
rocks, which acts on the light like a perfectly amorphous body. It is 
black in every position between crossed Nicols, as is a glassy substance. 
This at first deceived observers, but it is now known that this substance 
is chloritic in its nature. For such products as this last, and for other 
products of this nature, the compositions of which are only approximately 
understood, and which can be with justice referred to no mineral species, 
the name viridite is applied. 

In our diabase rocks, chlorite sometimes takes very pretty microscopic 
forms when its surroundings allow it to crystallize freely. For example: 
in Pl. 8, Fig. 5, is a representation of a section of diabase in which is 
seen a kind of cavity filled with calcite, and in the calcite are numerous 
little spherical concretions of chlorite. They are light green in color, 
and their radiated structure is not very evident. If, now, we put them 
between crossed Nicols, all their structure is developed, and they appear 
as radial discs traversed by a black cross, and look very pretty. This is 
what is illustrated in the figure, which will be readily understood. If the 
concretions are made of needles or plates of an hexagonal mineral, all 
those crystals which coincide with the plane of either Nicol prism will 
be black, while all others will be colored. As, now, in these concretions, 
crystals radiate out in all directions, each concretion must be crossed by 
two bars coinciding with the planes of the Nicols. The planes of the 
Nicols are indicated in the figure by the spider lines. This figure is 
drawn from a section of the diabase of Dixville. The centres of some 
of the concretions are filled with calcite. The other minerals in the 
section are a triclinic feldspar, recognized by its striations; augite, col- 
ored blue and yellow by interference of the rays; brown biotite; and 
the light calcite, with its characteristic cleavage. 


81. CorumsBitE [Fe (Cb, Ta)? O°]. 


This comparatively rare mineral has been found in the granitic veins 


of Acworth. The crystals there found possess an individual character 
VOL. Iv. 16 


122 MINERALOGY AND LITHOLOGY. 


from the large development of very acute octahedral planes, which pro- 
duce long, pryamidal summits on the crystals. These crystals were first 
described by Prof. C. U. Shepard, who made an excursion to Acworth 
for minerals in 1830. 

Columbite is a very heavy mineral, but there are wide variations in the 
gravities that have been taken upon specimens from various localities. 
This variation has been shown by Marignac to be due to the varying 
amount of tantalic acid, which increases the specific gravity in propor- 
tion as it is present in greater amounts. Pure columbate of iron has 
a gravity of 5.4, ahd pure tantalate of iron has a gravity of 8. Most 
of the columbites that have been analyzed are isomorphous mixtures of 
these two compounds, and have intermediate gravities. Marignac,* who 
investigated this subject, examined the columbite from Acworth, and he 
found that it had a specific gravity of 5.65, and, in accordance with the 
rule deduced, it contained 15.8 per cent. of tantalic acid. Columbite is 
also found associated with beryls at Plymouth. 


82. APATITE. [Ca® P? O', (Cl, FD]. 


This mineral is found abundantly in the vein of feldspar and quartz at 
Westmoreland, which has been previously referred to as a locality for 
molybdenite. The hexagonal crystals of apatite are there found abun- 
dantly, and are often large. Blue and green apatite in very pretty crys- 
tals is found at Grafton. Fine crystals occur in a bed of white lime- 
stone at Piermont. Apatite is also found in Jackson. 

Besides its occurrence in these fine crystalline varieties, it is almost 
universally spread about as a microscopic accessory constituent of the 
rocks. Though not constant, there is no variety of rock in which it is 
not sometimes found. When the crystals are not too minute it is easily 
recognized in thin sections, because it is always well crystallized, and 
consequently its sections are either hexagons or parallelograms. These 
needles and prisms of apatite pierce through all the other minerals that 
are common in rocks, and thus indicate that apatite was the first formed. 
The crystals are usually quite long in proportion to their size, a charac- 
ter that distinguishes them from nephelinite, which is almost the only 
mineral with which they might be confounded, but which is not found 
in our rocks, The sections of apatite are usually colorless, but when 


= Archiv des Sci. Physiques et Nat. Nouvelles, xxv, p. 24. 


MINERALOGY. 123 


revolved on the stage of the microscope, while only the lower Nicol is 
on the instrument, sections not parallel to the base show a greater 
absoption of light in one direction than they do in the other. 

In our eruptive rocks apatite is very abundant. It is usually micro- 
scopic, and only visible in thin sections. It is apt to be aggregated in 
some parts, while other parts of a section show none. Fig. 4 on Pl. 6 
represents apatite as it appears in the diabase at Bemis rook. It will 
be noticed that the needles, though small, pierce through all the other 
minerals. Such little apatite needles as these are apt to be seen in almost 
all our rocks. : 

But apatite, as a rock constituent, reaches much larger proportions 
without becoming macroscopic. For example: the augite sienite of Jack- 
son is filled with very perfect crystals which are large enough for optical 
examination. Their basal sections remain black when revolved between 
crossed Nicols, while the prismatic sections are black when the long axis 
is parallel with the plane of vibration of the light. Again: the gabbros 
at Waterville and Mt. Washington contain apatite in fine crystals of 
some size, but which first become evident in thin sections, and which 
offer some interesting peculiarities. Fig. 6 on Pl. 8 is a representa- 
tion of the apatite as seen in this rock. It will be noticed that the 
crystals have taken form and position without reference to any other 
constituent. They pierce the infusible olivine and magnetite as readily 
as the pyroxene and feldspar. It is the only substance that has crystal- 
line outlines. Some of these crystals are crowded full of minute cavi- 
ties. These cavities are heaped more abundantly in the centre of the 
crystals. Such crystals have been observed by Zirkel, Rosenbusch, and 
others. Again: some of the crystals appear to have other crystals run- 
ning through them. Sometimes there is but one large one, and again 
there are several. The sides of the interior crystals are parallel with 
those of the large one; but perhaps of more interest is the odd outline 
of many crystals, which in part are bounded by straight crystalline edges, 
while the remainder of the crystal is jagged and rounded, and bears all 
the appearance of having been eaten into by some reagent. Sometimes 
the whole half of a crystal looks as if thus dissolved, and sometimes 
merely a piece of the margin is destroyed. Effects of this kind have 
been observed in augite and hematite crystals in basaltic rocks, and they 


124 MINERALOGY AND LITHOLOGY. 


are explained by the supposition that during the cooling of the rock, 
when it had reached the temperature at which some minerals could crys- 
tallize, from some reason an elevation of temperature took place, and 
the crystals were again partially dissolved. To such a cause the odd 
outlines of these apatite crystals may be referred. 

From such microscopic proportions, apatite increases in size till it can 
sometimes be seen in the rock with the unaided eye. For example: a 
porphyritic diorite at Dixville notch is very black in color; but through 
it run fine white needles, which, with the lens, appear clear and glassy, 
and which it requires no microscope to recognize, nor to see how they 
pierce through all the other minerals which are porphyritically developed. 
As phosphoric acid is one of the essential constituents of plant food, the 
wide and universal distribution of apatite may be regarded as fortunate. 

If it is wished to make certain that a little hexagonal crystal in a rock 
section is apatite, one may use the reaction which Streng* applied to 
distinguish apatite from nepheline. 

Upon a crystal in a section with an uncovered surface, place a drop of 
a concentrated nitric acid solution of molybdate of ammonia, and watch 
the reaction with the microscope. The nitric acid will gradually decom- 
pose the apatite crystal, and in the drop there will presently appear a 
precipitate of the ammonium-phospho-molybdate, which has a bright yel- 
low color, and is composed of little crystals which are either octahedral 
or dodecahedral. This reaction cannot fail to be recognized, since this 
precipitate contains only 3.6 per cent. of phosphoric acid, and is corre- 
spondingly bulky; moreover, it is soluble in an excess of phosphoric 
acid, and hence directly over the exposed crystal no precipitate will be 
seen, but the precipitate will surround this spot with a crystalline wreath. 
Again: if a crystal be treated in like manner with a little drop of nitric 
acid, and, after it is well decomposed, a tiny bit of sulphuric acid be added, 
a precipitate of sulphate of lime will form; or, if the crystal be treated 
directly with sulphuric acid, its exposed surface will be quickly covered 
with a white coat of the same, which will prevent all further action. 


83. TrRIpHYLITE [(Fe, Mn, Li*)® P? O%]. ' 


At Grafton in our state this rare species is found more abundantly, 


*A. Streng, Tschermak’s Mineralogische Mittheilungen, 1876: Heft iii, p. 166. 


MINERALOGY. 125 


perhaps, than elsewhere in the United States. It occurs in the great 
granite vein; and in blasting for mica, large pieces of it, some of which 
weigh more than fifty pounds, have been thrown out. Mr. M. A. Brown 
reports that he obtained blocks of the pure mineral as large as water- 
pails. It is light blue in color, possesses a resinous lustre, and cleaves 
very well parallel to the base of its orthorhombic crystals, though the 
form of its crystallization cannot be determined from any faces that the 
mineral presents. The exterior of the masses and the cleavage surfaces 
are often blackened by the decomposition, which might be expected in a 
mineral so rich in protoxides of manganese and iron. A careful analysis 
of this triphylite from Grafton has been made by Mr. S. L. Penfield,* of 
the Sheffield laboratory, which is as follows: 


I. IL 

Phosphoric anhydride, . 2 ‘ . ‘i . 44.18 43.88 
Iron protoxide, 3 . . : : ‘ ‘ 26.09 26.38 
Manganese protoxide, . ‘ 5 : : a 18.17 18.24 
Lime, . a - i . : ‘ é ‘ 89 -99 
Magnesia, 6 - . 3 E . ‘ a 56 61 
Lithia, . : ‘ F ‘ 3 . - 8.77 8.81 
Potash, . ‘ 2 . - 3 : ‘ ‘ +32 «32 
Soda, . 5 5 ‘ : . ‘ -16 09 
Water, . : . F . fc % é 1.47 1.47 

100.61 100.79 


From this analysis, which is the first that has been made on an Amer- 
ican triphylite, Mr. Penfield calculates that the right formula is R* P 
O'-+ R? P O° (R standing for univalent elements, and R for the bivalent), 
a formula suspected by Rammelsberg to be the correct one, but to which 
no previous analysis has so closely approximated. Mr. Penfield points to 
the circumstance that our mineral is richer in manganese and lithia than 
the Bavarian mineral, which has been the chief subject of previous in- 
vestigation. 


ScoropirE—W AVELLITE. 


Scorodite, the hydrous arsenate of iron, has been reported as found at the Jackson 
tin mines. Its occurrence is doubtful. Wavellite is put in some lists of mineral local- 
ities as occurring at Bellows Falls. Mr. Downs, of Lebanon, says that it is not to be 


«Am. Your. Science, iii, vol. xiii, p. 425. 


126. MINERALOGY AND LITHOLOGY. 


found there, and he thinks that the prehnite which occurs there had deceived the 
finder. 


84. AutuniTE [Ca U? P? O” +- 10H? O]. 


This rare mineral has been found in little scales in the mica quarries 
at Acworth. The scales are little tabular crystals of the orthorhombic 
system. Its colors are light green and straw yellow. They are planted 
on the feldspar. 


85. WoLFramiTE [(Fe, Mn) W O*]. 


This heavy black mineral, which is everywhere a common associate of 
tin ores, has been identified as occurring in small amounts in the veins 
at Jackson with the cassiterite. 


86. Barire [Ba S O*]. 


This mineral has been found at Piermont. It occurs in bunches, and 
nests in the specular iron ore on Cross hill. It is white. There is little 
probability that it can be found in any such quantity as to make it an 
economic mineral. 


87. MELANTERITE (GREEN VitTRIOL) [Fe S Of + 7H? O]. 


In several parts of the state this salt is found as a result of the alter- 
ation and oxidation of iron pyrites. It occurs as a pulverulent kind of 
efflorescence, with a sweetish, astringent taste, and of a greenish-white 
color. It is soluble in water, and hence, when it forms upon the surface, 
it is quickly removed; but in enclosed spaces under ground it is pre- 
served in larger masses. It is noticeable as occurring in the beds of iron 
ore at Brentwood, Gilmanton, Rindge, Hopkinton, and Plymouth. It is 
liable, also, to be found in insignificant amounts in general in the pyr- 
itiferous rocks where the pyrites is exposed to air and moisture. 

This salt is easily recognized by its taste. By exposure, it is further 
oxidized to the sulphate of the sesquioxide of iron. 


88. Kauinire (Atum) [K? AP S* O* + 24H? O]. 


This mineral occurs as an efflorescence upon schists and shales, and 
is made by the action of sulphuric acid upon decomposing feldspar. It 


MINERALOGY. 127 


has been found at Bath, Bedford, and Walpole, in small, grayish-white 
efflorescences. It is easily recognized by its astringent taste. It is iso- 
metric in crystallization, but is usually found in mealy crusts. 


89. CatcirE [Ca CO*]. 


Calcite, although abundant enough in New Hampshire, is generally 
found in the massive condition, forming limestones, or, mixed with other 
minerals, forming calcareous rocks: hence its consideration belongs 
chiefly to lithology. Good rhombohedral crystals of calcite are, how- 
ever, found at Amherst, Surry, Warren, and the Notch. The variety of 
calcite called argentine is found at the iron mines in Lisbon. It is called 
argentine on account of its silvery lustre. 

In its more ordinary forms, calcite is widely distributed. It occupies 
veins in other rocks, as at Portsmouth, where it usually shows large 
cleavage surfaces, indicating coarse crystallization. It also forms thick 
beds interstratified with the surrounding rocks, as at Orford, Haverhill, 
Meredith, and Littleton. At the latter place it is filled with fossils; and 
the accumulation of beds of limestone is supposed to be largely due to 
the various organisms, whose calcareous shells are so often found in them. 
When the last remnants of this organic life have been destroyed, the 
limestones are white, while otherwise they are blue or gray. 

Calcite is constantly met with in thin sections of some classes of our 
rocks, sometimes as an original component, and sometimes as a second- 
ary product. Asa constituent of the basic eruptive rocks, it has plainly 
resulted from their decomposition, since it is usually found in little cav- 
ities, though it is also scattered all through the rock, as can be proved 
by moistening them with hydrochloric acid, and watching for an effer- 
vescence. Such minerals as pyroxene, by slow acting agencies, give 
up a part of their lime, and are converted into chlorite, while the basic 
feldspars quite easily part with theirs, as was shown in the discussion 
of anorthite. Thus results the calcite which so commonly fills all the 
pores of such rocks, and by such processes the lime has been separated 
from the original basic rocks to form beds by itself. 

The microscopic characters of calcite, as seen in thin sections, are 
very characteristic. It is strongly double refracting, and the light 
which passes through a crystal with its vibrations in a plane par- 


128 MINERALOGY AND LITHOLOGY. 


allel to the vertical axis of the crystal (extraordinary ray), are not 
so much refracted, and pass through with more ease than do those at 
right angles thereto. Hence sections of calcite exhibit absorption, 
and when viewed with the microscope with only the lower Nicol on the 
instrument, they are brighter and clearer in certain positions (that is, 
when the plane of the Nicol and the plane of the extraordinary ray 
coincide) than they are in others. With crossed Nicols, calcite gives no 
very brilliant colors, but when revolved on the stage of the instrument 
there are alternations of great brightness with the darkness. A peculiar 
silvery color is ordinarily obtained, which is very characteristic. Of 
course, basal sections are always dark between crossed Nicols; and in 
such sections, if the ocular is taken out of the instrument and the Nicol 
replaced, the black cross and colored rings can be seen. In quite thin 
sections, in order to see this, the higher powers must be employed. The 
perfect rhombohedral cleavage of calcite is always very evident in thin 
sections. 

Most especially in our marbles, and in the calcite that is found in the 
crystalline rocks as an apparently original product, an appearance is seen 
that resembles in a degree the polysynthetic twinning of feldspar. The 
calcite in such rocks possesses a laminated structure which is usually 
only brought into view when a thin section is brought between crossed 
Nicol prisms, and then it is very evident. The plane of the laminz does 
not correspond with the cleavage, but is parallel to planes of the obtuser 
rhombohedron —4 R. Quite often two sets of these laminz are seen 
crossing one another, and as there are three like rhombohedral planes, 
so it is evident that there might be at the same time a twinning parallel 
to all at once, and that if the crystal were cut in the proper direction all 
three sets of these laminz might be at once visible. The appearance of 
crystals exhibiting these laminze between crossed Nicol prisms is seen 
in Fig. 5 on Pl.6. In some of the grains two systems of laminz are 
seen at once. The different shades of the calcite depend, of course, 
upon the varying relations of the axes in the different grains to the 
plane of the light. This figure is drawn from calcite in the micaceous 
diorite at Stewartstown. It represents very well what is to be seen in 
sections of any of our limestones, and in the calcite enclosed in many of 
our rocks. Stelzner was the first to suggest that the entire irregularity 


MINERALOGY. 129 


of the grains of calcite in limestones, and these twin lamelle, are very 
probably due to the effects of the pressure which was exercised upon 
the rocks during their metamorphism, because Reusch had already 
shown that these lamellz could be induced in simple calcite crystals by 
slicing off two of the opposite edges of a cleavage rhombohedron, and 
exerting a gradually increasing pressure upon the little faces thus made. 
When calcite is formed in cavities and cracks of the rock, where the 
rocks had plainly taken their last form before the calcite was produced 
by their decomposition, this twinning (if it is a twinning) is not often 
found ;—a fact which might be expected if the above mentioned theory 
is correct. 

In the amygdaloidal cavities calcite sometimes assumes pretty, micro- 
scopic forms. For example: in Fig. 3 on Pl. 6 are represented the 
amygdaloids which abound in the olivine diabase at Campton falls, and 
which are filled with analcite. Before the analcite was formed, there 
was, however, a growth of hexagonal prisms of calcite, which were ter- 
minated with the planes of an obtuse rhombohedron. In some of the 
cavities these prisms had grown from side to side, thus forming a bar 
across the little chamber. 

Some of our limestones, as, for example, those at Littleton, when ex- 
amined in thin sections, exhibit peculiarities ‘in the cleavage. The lines 
are no longer straight, but traverse the grains in curves. This is prob- 
ably another result of pressure which at some time acted upon the stone. 

In some limestones the organic matters, which were originally present 
in the shells, etc., have not been entirely destroyed, but are left in a bitu- 
minous condition; and these rocks, when struck, give forth a foul odor, 
from which the stone is called fetid limestone or stinkstone. Such a 
limestone occurs at Orford. 

Numerous analyses of New Hampshire limestones have been made by 
Dr. Jackson and others.* It would be profitless to introduce them here, 
since their bearings are merely economic. They show all grades of im- 
purity, from the pure white limestone of Haverhill, which contains 99.3 
per cent. of calcium carbonate, to a gray, Cornish limestone, which con- 
tains 63.4 per cent. of impurities. Thus, by the gradual introduction of 
other minerals, limestones grade into other rocks. Besides this kind of 


* Geology of New Hampshire, Dr. C. T. Jackson, pp. 173-175. 
VOL. IV. 17. 


130 MINERALOGY AND LITHOLOGY. 


impurity, in some of our limestones the analyses show a greater or less 
replacement of the calcium by magnesium. By this replacement, calcite 


approaches dolomite. 
go. DotomitE [(Ca, Mg) CO*)]. 


Pure dolomite is not very common in our state, though the limestones 
very often contain more or less magnesia, It exists in considerable quan- 
tities at Lyman, and also at Plainfield. It is readily distinguished, be- 
cause it does not effervesce in cold, diluted hydrochloric acid. Our 
dolomites are gray, and quite impure. Dr. Jackson’s analysis of the 
Plainfield dolomite indicates the presence of about thirty per cent. of 
impurities, which are of mica, quartz, and other silicates. In thin sec- 
tions, it does not show the twin laminations in polarized light that are 
shown by calcite. 


gt. ANKERITE [(Ca, Mg, Fe, Mn) CO*]. 


This mineral, in which the magnesia of a dolomite is more or less 
completely replaced by iron and manganese, is commonly present in the 
quartz veins that have been shown to be auriferous, and is, indeed, char- 
acteristic of them. It is found in good rhombohedral crystals of a honey- 
yellow color, and on heating them in the reducing flame of the blow-pipe 
they become magnetic. Littleton, Lisbon, and Lyman are localities where 
they are abundantly found. In some veins the quartz, though containing 
no ankerite, is filled with rhombohedral cavities, showing that there once 
were crystals that have been dissolved away. 


92. SIDERITE AND SPHAEROSIDERITE [Fe CO?]. 


The carbonate of iron, as has been before noted, is common in the 
deposits of bog-iron ore, but not as a mineral of interest, since its pres- 
ence is only shown by the effervescence that takes places when they are 
treated with acid. Near us, at Plymouth, Vt. there are deposits of sid- 
erite. 

Sphaerosiderite is a concretionary variety of siderite that is found in 
globular or mammillary forms. This mineral is quite often found as a 
constituent of our rocks, as a lining of cavities; but it is chiefly micror 
scopic. For example: in the olivine diabase of Campton falls, the little 


MINERALOGY, I3I 


cavities which were represented in Fig. 3 on Pl. 6 to show the analcite, 
were all first coated with sphaerosiderite, which often assumed in them 
the most fantastic forms. In the thin sections it is deep yellow in color, 
appears often agate-like in structure, but in polarized light appears to be 
an aggregate of very fine fibres or scales. It is not uncommon to find 
some of this substance in sections of our basic rocks. 


93. RuopvocurositE [Mn CO*]. 


This mineral is found at Winchester. When pure, it has a light rose 
color ; but our mineral is usually blackened by decomposition. It is not 
common, and does not show its crystalline form, which is rhombohedral. 


94. MaracuitEe [Cu? CO* + H’0O]. 


This bright green carbonate of copper, though not found in well crys- 
tallized forms, occurs at Littleton in the slaty rocks, in stellated groups 
of needle-like crystals. In the condition of a green crust it has been 
found in the rocks at Franconia, Hanover, Dalton, and Orford. It is 
associated with sulphurets of copper, and generally results from their 
decomposition. 

95. Azurite [Cu C? O’ + H’0}. 


The blue carbonate of copper is associated with the green at Fran- 
conia. Like the malachite, it is in the condition of a non-crystalline 
earthy crust. 


* * * * * * * * * 


In concluding this chapter, what has been said with reference to the 
localities of minerals may be very conveniently summed up in a cata- 
logue of the towns, and the minerals that, to the knowledge of the sur- 
vey, have been there identified. This catalogue not only embraces those 
mineral occurrences that have been referred to in the preceding pages, 
but also includes many others which in those connections it would have 
been tedious to enumerate, and mention of which is more serviceable 
when placed here. Though many of these minerals have been known 
to exist for a century, still to the field laborers on this survey, with Prof. 


Hitchcock at their head, the people are indebted for a knowledge of a 
large number of these occurrences, 


132 MINERALOGY AND LITHOLOGY. 


CATALOGUE OF MinERAL LocatiTies In New HampsuHire. 


Acwortu. Beryl, tourmaline, mica crystals, orthoclase, albite, columbite, rose 
quartz, autunite. 

ALEXANDRIA. Mica crystals. 

AusteaD. Mica, black tourmaline, albite, molybdenite, andalusite, staurolite. 

Aton. Arsenopyrite, galenite. 

Amuerst. Jdocrase, yellow and cinnamon garnet, amethyst, calcite, magnetite, 
pyroxene, limpid quartz. 

ANDOVER. Andalusite, graphite, milky quartz, rose quartz. 

BarTLeTT. Hematite, magnetite, limonite, danalite, quartz crystals, smoky quartz. 

BARRINGTON. Graphite, tourmaline, bog-iron ore. 

Batu. Galenite, chalcopyrite, alum. 

BEDFORD. Alum, tremolite, epidote, graphite, black, green, and yellow mica, limpid 
quartz, tourmaline. 

BELLows Fats. Cyanite, staurolite, prehnite. 

BENTON. Quartz crystals, magnetite, efzdote, beryl. 

BERLIN. Magnetite, amethyst, pyrite, chalcopyrite, hornblende. 

BRENTWOOD. Pyrites, sulphur, melanterite. 

BRISTOL. Graphite, galenite. 

Campton. Beryl. 

CaNnAAN. Gold in pyrite, garnet. 

CANTERBURY. Soapstone. 

CHARLESTOWN. Staurolite, chiastolite, bog-iron ore, cyanite, prehnite. 

CuHatHam. Beryl. 

CHESTER. Graphite, tremolite, sulphur. 

CHESTERFIELD. Limonite. 

CHICHESTER. Black tourmaline. 

CLARKSVILLE. Galenite. 

ConcorpD. Fibrolite. 

Connecticut Lake. Chalcopyrite, galenite. 

‘CorNisH. Staurolite, smoky quartz, rutile in quartz, stibnite, tetrahedrite. 

Croypon. Iolite, chalcopyrite, Ayrrhotite, pyrite, blende. 

Darton. Chalcopyrite, bornite, galenite, garnet, malachite. 

DORCHESTER. Garnet. 

DuNBARTON. Arsenopyrite. 

Easton. Magnetite. 

EFFINGHAM. Molybdenite. 

ELLsworTH. Galenite. 

ENFIELD. Galenite, gold, green quartz, ripidolite, brown and gray cymatolite, stau- 
rolite, margarodite, paragonite. 


MINERALOGY. 133 


Epsom. Black tourmaline, arsenopyrite. 

ERROL. Garnet. 

ExeETER. LZidote, hornblende. 

FARMINGTON. Andalusite, galenite. 

FRANCESTOWN. Soapstone, arsenopyrite, red and yellow quartz crystals. 

FRANCONIA. Arsenopyrite, chalcopyrite. 

GARDNER Mountain. Chalcopyrite, pyrite, galenite. 

GILFORD. Magnetite, native lodestone. 

GILMANTON. Red and yellow quartz crystals, tremolite, epidote, muscovite, tourma- 
line, limonite, jasper, hornstone. 

GORHAM. Quartz crystals. 

GosHEN. Graphite, micaceous hematite, black tourmaline. 

GraFton. Mica, albite, beryl, tourmaline, garnet, apatite (blue, green, purple, and 
white), fluorite, triphylite, arsenopyrite, cleavelandite, columbite, quartz crystals, 
rose quartz, molybdenite, rhodonite. 

GRANTHAM. Gray and brown staurolite. 

Groton. Arsenopyrite, J/ve, green and yellow Jderyl, muscovite crystals, large 
feldspar crystals, columbite, quartz crystals. 

Hanover. Garnet, black tourmaline, quartz, hornblende, cyanite, anorthite, 
epidote, pyrrhotite, red and yellow quartz, zoisite, malachite, gold. 

HAVERHILL. Garnet, arsenopyrite, arsenic, galenite, blende, pyrite, chalcopyrite, 
pyrrhotite, marcasite, tourmaline, bog-iron ore, steatite. 

Hepron. JSeryl, andalusite, graphite. 

HILLSBOROUGH. Graphite. 

HINSDALE. Molybdenite, indicolite, black tourmaline, rhodonite. 

Jackson. Cassiterite, arsenopyrite, arsenic, drusy quartz, fluorite, apatite, sag- 
netite, molybdenite, wolfram, chalcopyrite, copper. 

JAFFREY. Cyanite, limonite. 

Mr. KearsarGE. Andalusite, tourmaline, rose quartz. 

KEENE. Graphite, milky quartz, rose quartz, fibrolite, soapstone. 

Kincston. Limonite. 

LANCASTER. Bog-iron ore, steatite. 

Lanparr. Gold, olybdenite, pyrrhotite, magnetite. 

Lanepon. Chiastolite. 

Pence gene aged : eget magnetite, pyrite, bog-iron ore, hornblende, 
, gold, epidote, chlorite, saponite, kaolinite, graphite. 

LempsTER. Beryl, andalusite. 

LIVERMORE. Zinc blende (head of Swift river). 

Loupon. Galenite. 


Lispon. Staurolite, black and red garnets, magnetite, hornblende, epidote, zoisite 
. ee . ? 
hematite, arsenopyrite, galenite, gold, ankerite. At Franconia Iron Mine—o, 
- oe . as Bi 
blende, epidote, soisite, hematite, magnetite, titanic iron, black and red garnet. 
S5 


134 MINERALOGY AND LITHOLOGY. 


arsenopyrite, danaite, chalcopyrite, molybdenite, prehnite, green quartz, malachite, 
azurite, cyanite. 

Littteton. Ankerite, gold, bornite, pyrite, chalcopyrite, malachite, menaccanite, 
chlorite, sericite. 

Lyman. Gold, ankerite, arsenopyrite, dolomite, galenite, pyrite, copper, pyrrhotite. 

Lyme. Cyanite, black tourmaline, rutile, pyrite, chalcopyrite, stibnite, staurolite, 
molybdenite, cassiterite. 

Mapison. Galenite, blende, chalcopyrite, limonite. 

MANCHESTER. Biotite crystals, drusy quartz. 

MARLBOROUGH. Beryl, mica, fibrolite, rose quartz, crystals of feldspar. 

Martow. Beryl, andalusite. 

MEREDITH. Galenite. 

MERRIMACK. Rutile. 

MIDDLETON. utile, arsenopyrite. 

Miuan. Chalcopyrite, galenzte, blende. 

MILLSFIELD. Seryl, garnets. 

Monapnock Mountain. Andalusite, fibrous hornblende, garnet, graphite, ortho- 
clase, tourmaline, beryl, fibrolite. 

Monroe. Blende, chalcopyrite, pyrite. 

Moose Mountain (Hanover). Quartz crystals, quartz with rutile, guartz with 
acicular tourmaline. 

MoosILauKE Mountain. TZourmaline. 

MovuttongzoroucH. Hornblende, tourmaline, bog-iron ore, pyrite. 

NELson. Graphite. 

NeEwsury. Fluorite. 

NEWINGTON. Garnet, tourmaline. 

New Ipswicu. Beryl, kaolinite. 

New Lonpon. Beryl, molybdenite, muscovite crystals. 

Newport. MMolybdenite crystals, staurolite. 

NortHwoop. Graphite, pyrite. 

NOTTINGHAM. Limonite. 

ORANGE. Blue beryl, chrysoberyl (at Orange summit), Amazon stone, mca, albite, 
tourmaline, apatite, galenite, limonite. 

OrForD. Brown tourmaline, steatite, rutile, cyanite, limonite, chalcopyrite, chal- 
cocite, melaconite, malachite, galenite, garnet, graphite, titanic iron, molybdenite, 
pyrrhotite, rzpidolite. 

PELHAM. Steatite, in boulders. 

PEMBROKE. Limonite. 

Mt. PEQUAWKET. Andalusite, damourite. 

PIERMONT. JMicaceous hematite, ordinary hematite, barite, green, white, and brown 
mica, apatite, titanic iron. 

PiTTsBuRG. Gold, hematite. 


MINERALOGY. 135 


PITTSFIELD. Galenite. 

PLAINFIELD. Chalcopyrite, limonite, magnetite, gray and brown staurolite, dolo- 
mite. 

PrLymoutH. Columbite, beryl. 

PORTSMOUTH. Epidote. 

RayMonD. Rose quartz, quartz crystals. 

Ricumonb. Iolite, rutile, steatite, pyrite, anthophyllite, talc, pinite. 

RocHESTER. Andalusite. 

Rumney. Beryl, galenite, blende, graphite. 

RYE. Chiastolite. 

SADDLEBACK MounTAaIn. Black tourmaline, garnet, spinel. 

SALIsBuRY. Limonite. 

SHELBURNE. Galenite, black blende, chalcopyrite, pyrite, pyrolusite. 

SPRINGFIELD. Zeryl, manganesian garnets, massive garnet, albite, mica, tourma- 
line, rose quartz. 

Stark. Labradorite. 

Success. Quartz crystals. 

SuLLivan. Slack tourmaline, beryl. 

Surry. Amethyst, calcite, galenite, hematite, limonite, pyrrhotite, plumose cy- 
anite, tourmaline. 

Sutton. Beryl, eraphite. 

SWANZEY. Magnetite, graphite, potstone. 

TamMwortTH. Galenite. 

THORNTON. Graphite. 

Troy. Andalusite, graphite. 

Unity. Chalcopyrite, pyrite, magnetite, zolzte, chlorophyllite, green mica, actinolite, 
garnet, titanic iron, tourmaline. 

WAKEFIELD. Epidote, molybdenite. 

WaLpoLe. Chiastolite, alum, graphite, rose- and straw-colored mica, staurolite, 
prehnite (Drewsville), fibrolite. 

Warner. Talc, soapstone. 

Warren. Chalcopyrite, blende, epidote, quartz, pyrite, tremolite, galenite, rutile, 
talc, molybdenite, cénnamon garnet, pyroxene, hornblende, beryl, calcite, cyanite, cym- 
atolite, tourmaline (massive). 

WASHINGTON. Graphite. 

WATERVILLE. Labradorite. 

Weare. Arsenopyrite, soapstone, asbestus. 

WENTWORTH. Graphite, galenite. 

WESTMORELAND. MMolybdenite, fluorite, chalcopyrite, apatite, blue feldspar, bog 
manganese, quartz, amethyst. 

WuitE Mountains. At Notch—Green octahedral fluor spar, quartz crystals, ga- 
lenite, pyrrhotite, ankerite, d/ack tourmaline, garnet, chiastolite, albite, beryl, chlorite, 


136 MINERALOGY AND LITHOLOGY. 


calcite, amethyst, jasper, smoky quartz, gieseckite. On Mt. Washington—Rose quartz 
(on Glen House road), prochlorite. : 

WHITEFIELD. Molybdenite, massive garnet. 

Witmort. Beryl. » 

Witton. Menaccanite. 

WINCHESTER. Pyrolusite, rhodonite, rhodochrosite, psilomelane, magnetite, gran- 
ular quartz, spodumene. 

WINDHAM. Garnet. 

WINNIPISEOGEE LAKE. Hornblende (on Red hill), beryl (on islands). 

Woopstock. Galenite. 


Note. The names of minerals are italicised when the specimens obtained are better 
than ordinary. 


Moat Mountains AND NorTH Conway. 


CHAPTER II. 


LITHOLOGY. 


woe now briefly considered the mineral species that have been 
found in our state, it is intended in this chapter to describe the 
rocks that are composed of aggregates of them. Lithology is a geolog- 
ical science, and therefore it does not deal with small and rare deposits, 
which, although of interest to the mineralogist, are of little importance 
in the structure of a world; but whenever a mass of material of such 
extent as to constitute a feature of the earth’s crust is found, this mass 
is called a rock, and it is considered in the science of lithology. New 
Hampshire is a favorite field for the pursuit of this study. The surfaces 
of many states of our country are covered by rocks and soils which pre- 
sent little diversity ;—but we live in a region which has been the scene 
of disturbances which have uplifted grand mountains and upturned 
the crust of the earth, presenting to us for our study many most deeply 
buried strata; and through rifts in these strata the underlying molten 
matters, which form a very diversified system of eruptive masses, have 
reached the surface. On our rocks the modifying influences of long 
ages have left their marks; and therefore the fundamental question of 
lithology,—Of what is the earth composed, and how did its constituent 
rocks reach their present condition ?—_becomes one of some complexity, 
but also one of much interest. 


The age and distribution of our rocks are topics which have been dis- 
VOL. Iv. 18 


138 MINERALOGY AND LITHOLOGY. 


cussed in other parts of this report. It is the object of this chapter to 
supplement the work in the field with the results obtained in the labora- 
tory. It aims clearly to explain the composition of specimens of rocks 
which have been selected as typical, and to discover as much as possible 
of the origin, mode of formation, and history of the masses, by the study 
of samples. Microscopic study has of late been far the most fruitful in 
_ the growth of the science, and therefore this method has been chiefly 
employed. The value of work of this kind in connection with geological 
surveys has been sufficiently well demonstrated by the labors of others; 
and if this work is uninteresting it is the fault of the writer, for our 
rocks furnish a most beautiful series of objects for microscopic investi- 
gation. 

The field is also comparatively new. Dr. F. Zirkel, of Leipzig, one of 
the most eminent authorities upon microscopic lithology, has written a 
very valuable and most beautifully illustrated treatise on the rocks col- 
lected by the United States Fortieth Parallel Survey (C. King, in charge). 
But those rocks belong largely to the newer formations; and with the 
exception of isolated specimens which have fallen into the hands of 
lithologists, the microscopic study of our old crystalline rocks has been 
but little prosecuted, and hence a systematic investigation of their 
microscopic structures and the properties of their constituent miner- 
als, opens a field which cannot be barren of interest. 

But the results which in the past ‘have been achieved by other laborers 
in other ways must not be lightly passed. The laborious chemical 
researches of Dr. T. Sterry Hunt, and the deductions which he has 
drawn from them, are familiar to all, and lose no value to us because 
performed on allied rocks in other regions. Incidental to his geological 
investigations, most valuable lithological conclusions have been obtained 
by Prof. J. D. Dana; and besides these gentlemen, a large number of 
able geologists have studied, with greatest care, either parts of our forma- 
tions, or others closely allied to them. If, now, in approaching this sub- 
ject from a somewhat different standpoint, in many cases the same con- 
clusions are reached, the author would wish to add them to the credit of 
those gentlemen. He would also recognize the labors of the European 
lithologists who have most carefully studied allied rocks by the same 
methods here employed, and whose results constitute the larger part 


LITHOLOGY. 139 


of lithological literature. Every new region, however, furnishes new 
variations on old facts, and thus helps to strengthen, and sometimes to 
build up. 

Before proceeding to the description of particular species of rocks, a 
few remarks of a general character, applicable to the rocks of our 
region, may make more simple the method of arrangement adopted in 
this treatise. 

A hundred minerals have been described as occurring in our state; of 
these, more than half are now classed out as of no importance to lithol- 
ogy, and the diversity in our rocks is produced by the various combina- 
tions of the remainder. At times we have a simple aggregate of one 
mineral, and, again, a most complex mixture. Yet it is not like the for- 
mation of words, without number, by combinations of the letters of the 
alphabet. The subject obtains interest from the fact that rocks resultant 
from the combinations of minerals are limited in number and in kind by 
certain chemical considerations. Now, the mere determination of the 
mineral ingredients of a rock has little besides an economic importance. 
The subject, as a science, has its chief interest in the study of the condi- 
tions under which our earth has become thus covered with such very 
diverse accumulations of material; how the particular minerals became 
combined in such ways; and how they obtained their present form and 
condition. Bound thus to a central idea, the study of the mineral com- 
position becomes interesting; and this central idea should give the basis 
for classification and arrangement of the material for study. 

The following is the general mode of origin of diversity in rocks: The 
earth was once in a condition of igneous fluidity, and while in this con- 
dition, with the particles of matter freely movable, the various materials 
that composed the earth’s outer zone would enter into their most stable 
combinations, and would form one immense, homogeneous mass; and 
thus the first crust of the earth may be supposed to have been quite uni- 
form in character and composition, with only the variations induced by 
gravity, which would draw heavier materials to a lower level. But the 
conditions of chemical stability, in a state of igneous fusion, are quite 
different from those in the cold. Not merely are certain elements, with 
strong affinities for one another, but which in the heat are separated from 
one another by different degrees of volatility, brought to act upon one 


140 MINERALOGY AND LITHOLOGY. 


another again, but in the cold many stable compounds are formed in the 
presence of one another which are impossible in the heat, while at the 
same time entirely different mechanical agencies are brought to bear 
upon matter. The original crust is now so deeply buried as to be inac- 
cessible to the student; but it is plain that the nearest spot to which it 
can be approached is the starting-point of lithology, and the study of the 
various changes and modifications which this matter has passed through 
will indicate the reason for the physical and chemical diversities which 
are now so prominent. 

What rocks are most nearly like the earth’s original crust is not hard 
to decide. Chemistry points to a basic, siliceous rock, from theoretical 
considerations ; and geologists find such rocks cutting through the oldest 
formations, indicating that they came from a lower level. These rocks, 
of which diabase and basalt are typical, are found with tolerably uniform 
composition all over the world. Whether the rocks mentioned, or any 
allied to them, are really composed of matter erupted from an unsolid- 
ified zone of the earth’s original substance, matters not here. These 
rocks fulfil the conditions that must have existed, and at least represent 
most nearly the first rocks from which all others have been derived. 
With the study of the basic, eruptive rocks, our lithology therefore be- 
gins. 

But it has been deduced, as a result of the labors of this survey, that 
all our rocks are very old. A little area of Helderberg limestones repre- 
sents the youngest of our stratified rocks, while the larger area is cov- 
ered by archzan deposits,—and so all our rocks have been subjected to 
the influence of ages of time. At the risk of being wearisome, in the 
mineralogical chapter it was necessary to describe how almost every 
mineral, when microscopically examined, was found to be subject to some 
mode of decomposition peculiar to itself ;—therefore sections cut from 
the various rocks of our state are continually presenting to us the pro- 
cesses of decay and change by which old rocks are changed into new 
ones; and, by illustrating as clearly as possible these processes, it is 
hoped to simplify our lithology. 

It must be borne in mind that rock species, which are made of mixt- 
ures of minerals which vary in their relative amounts, can have no such 
definite boundaries as do minerals which are definite chemical compounds; 


LITHOLOGY. 141 


but, on the contrary, by the gradual introduction of new minerals, and 
the elimination of others, they so gradually approach and grade into one 
another as to make it a matter of personal judgment where the dividing 
line must be drawn. Hence, the science of lithology is unsatisfactory 
and puzzling to those who pursue it with the idea of the classification 
and nomenclature of their specimens in the foreground, while the indefi- 
nite limits of species, and the gradations that occur between different 
rocks, are aids to those who study the subject with the idea of discov- 
ering the nature and origin of rock types. 

The study of a rock begins in the field; and though in fie laboratory 
the student with his microscope can surmise many facts that are properly 
ascertained where the rocks are in place, the necessity of field work is 
not at all diminished. The first point to be noted in the field is the rela- 
tionship of the given rock to those about it, and on this relationship the 
chief division of rocks is founded. Fragmental rocks are masses of loose 
or merely cemented sedimentary materials. The crystalline schists are 
masses of sediments, the materials of which have been rearranged in 
crystalline form. These two kinds of rocks show plain evidences of 
stratification. Intrusive rocks are those that bear no relationship to 
those about them, save that they form dykes or veins in them, and can- 
not be said to belong to the formations in which they occur. Between 
these groups of rocks, the members of which are either plainly stratified 
or plainly intruded, there is a group of rocks which are subject to dis- 
cussion. At times they appear to be stratified, at times they are plainly 
intrusive ; but more often they show plain evidence of neither one nor 
the other. In New Hampshire all these groups are very fully repre- 
sented. Intrusive rocks are constantly met with, stratified rocks are 
everywhere, while there are members enough of the intermediate group, 
the relationship of which it is the duty of a treatise of this kind to dis- 
cuss. It will thus be seen, that, as the boundary lines between species 
are indistinct, so, too, are those that divide the great classes from one 
another. This will make still more plain the force of what has been said 
on the subject of classification, while it may again be said that this indefi- 
nite division is a help towards the understanding of rocks in general; 
for it is easier to travel a smooth road than to spring from stone to 
stone. As an adjunct to geology, the difficulties with which lithology 


142 MINERALOGY AND LITHOLOGY. 


is beset partially disappear, for classification becomes its least interest- 


ing feature. 


MeEtHuops oF STupyY. 


In reference to the application of the microscope to this subject, suffi- 
cient has already been said in the introduction to the first chapter, while 
the optical properties of all of the minerals that are found as constituents 
of our rocks have been indicated in describing them. In this chapter, 
therefore, it will be assumed that no explanation of the optical effects 
that are reproduced in the figures is necessary. Some of the figures 
represent rocks as they appear with ordinary light, and hence need no 
explanation. When crystals are represented as they appear in polarized 
light, it is to be understood that the position of the Nicols is a determi- 
nate one only in those cases where the planes of vibration of the light in 
the Nicols are represented by cross lines on the figure; for, as a rule, 
where nothing is to be gained by indicating the position of the axes of 
elasticity in crystals, the Nicols have been so placed as to obtain colors 
which would not complicate the lithography. I refer those again, who 
wish systematic instruction on this subject, to the works of Zirkel and 
Rosenbusch.* 

If, as has been shown, the microscope with ease and certainty deter- 
mines minerals where chemical analysis fails, discovers ingredients in 
rocks the presence of which was not before suspected, and brings to 
the foreground many little circumstances which prove to be exceed- 
ingly weighty, there are, too, cases where it fails, For example: in accu- 
rately prepared sections from crystals of the triclinic feldspars, one can 
easily determine the species ; but when the crystals lie scattered at hap- 
hazard, though one can easily recognize them as being of triclinic feld- 
spar, one cannot often determine the species, and in some such cases 
chemical analysis is advantageously employed. Not long since the sci- 
ence was largely dependent upon chemistry for its determinations, and 
cumbersome methods for the separation and determination of ingredients 


* The work of A. von Lasaulx, ‘Elemente der Petrographie,”’ is a condensed presentation of general lithol- 
ogy, embracing the latest discoveries. The two volumes by Rosenbusch, on Mikroskopische Physiographie, 
are very systematic and very valuable. The first volume treats of the minerals of importance in lithology, and 
the second volume treats of the massive rocks. 


LITHOLOGY. 143 


were instituted, which now are only employed in most special cases. To- 
day, chemical analysis, with such ends in view, is only undertaken when 
the necessity is indicated by the microscopic examination. 

But there is a value beyond the determination of mineral constituents, 
which is attached to chemical analyses. Knowing the mineral constitu- 
ents, it may be desired to determine their proportion; or, the ultimate 
composition of a rock, without reference to its mineral constituents, may 
be desired. On the data furnished by such analyses much reasoning has 
been based, and many valuable conclusions arrived at, concerning the 
chemical relationship of rocks formed at different times and in different 
ways. The tabular works of J. Roth contain most of the analyses 
which have been made. 

In the preparation of this work, some hundreds of thin sections of our 
rocks have been prepared and examined, and chemical analyses have 
been made, where an end seemed likely to be gained. It is hoped that 
the specimens chosen as typical have been so carefully selected, that per- 
sons can recognize, in the descriptions, the rocks from other localities in 
the state which are not discussed, so that these pages may be found to 
contain a tolerably complete presentation of the lithology of New Hamp- 
shire. 

The following are the species of rocks that are considered in this re- 
port, and the order in which they are described : * 


: Basic EruptTive Rocks. 


Diabase. 
Diorite. 
Gabbro. 
Acipic UNSTRATIFIED Rocks. 
Felsitic. 
Felsite. 


Porphyritic Felsite. (Porphyries.) 


* In this classification only the most general divisions of the rocks are given, and the varieties and sub-varieties 
are not enumerated. In the report, the extensive introduction of adjective terms in the nomenclature of varieties 
and sub-varieties will be noticed. Many of these rocks have received special names ; but convenience and sim- 
plicity are both promoted by making specific names dependent only upon the most fundamental distinctions. 
The introduction of special names for rocks which possess particular local characteristics, or peculiar accesso- 
ries, is not favorable to a science the characters of whose species are so very inconstant as are those of lithology. 


144 MINERALOGY AND LITHOLOGY. 


Granitic. 
Granite. 
Sienite. 
CRYSTALLINE SCHISTS. 
Gneiss. 


Mica Schist. 
Argillitic Mica Schist. 
Quartz Schist. 


Greenstones. 
Metamorphic Diorite.* 
Amphibolite. 
Chlorite Schist. 


Harr CrysTALuInE Rocks. 


Clay Slate. 
Quartz Schist. 


Minerals as rocks have been treated of in the preceding chapter. 
Fragmental rocks have been discussed in the part upon Surface 
Geology, and are hence very briefly treated here. 


BASIC ERUPTIVE ROCKS. 


The investigations which thus far have been made upon our basic 
eruptive rocks leave much to be desired in detailed knowledge of their 
nature and composition. The dark-colored rocks which intrude them- 
selves, here abundantly, there sparingly, through our crystalline strata, 
have in some cases been correctly identified from their coarse-grained 
and porphyritic varieties ; but, when examined with the microscope, rocks 
which are apparently alike are found to be so different,—so many unsus- 
pected ingredients are found to be present, so many suggestive structu- 
ral effects are seen,—that it becomes plain that such study is necessary 


Moreover, in the ‘present confusion (especially among writers in the English language), while every writer uses 
his own nomenclature, and impresses on each name his own signification, the adopted method will most certainly 
convey the idea that is intended. 

No new names have been introduced, though I am certain that, according to precedent, material is at hand. 
This feature of my report I hope will be commended. 

* This rock is mostly massive. I think it will be found satisfactorily explained, however, why it is considered 
in this connection, 


LITHOLOGY. 145 


for their elucidation. Before proceeding to special descriptions, we will 
consider their position among rocks of this class, and what they have in 
common which isolates them as a well defined group. 

The first great division of eruptive masses is into basic and acidic 
rocks. The first are characterized by a content of silica lower than sixty 
per cent. and basaltic rocks are typical of them. The acidic rocks are 
lighter in gravity, contain more silica, and trachyte and quartz porphyry 
are typical examples. These two great classes were instituted by Bun- 
sen, and were by him supposed to represent two great zones or layers of 
fused matter, which originally underlaid the crust of the earth, separated 
from one another by their specific gravities. He supposed that at differ- 
ent periods of the earth’s history matter was erupted from different 
layers of this mass beneath, and thus we have basic and acidic eruptive 
rocks, and also intermediate varieties, which represent the intermediate 
zone of the molten matter. By further study, this once so plausible 
theory has been mostly done away with. It is now considered that the 
shifting of sediments, and vast movements in the earth’s crust, may ren- 
der fluid, or plastic, beds of previously solid matter; and thus, at different 
times and at different places, the crust of the earth may be underlaid by 
beds of molten material, which may be composed of the unstratified, 
original matter of the earth’s exterior, or of sediments of variable com- 
position; and through rifts in the superficial beds we may hence obtain 
most diverse eruptive rocks. The two great divisions of rocks are, 
however, maintained, and we have in our state numerous representatives 
of both classes. It is the basic division that we are now to consider. 

Besides this great chemical distinction, there are certain geological 
conditions which sub-divide eruptive rocks. It is found that those rocks 
which have been erupted in the later periods of the earth’s history pos- 
sess certain characteristics that distinguish them from others. They 
show in general the effect of more rapid cooling, and are either com- 
posed largely of glassy matters, or enclose more or less glassy material 
in their masses. They often possess certain types of microscopic struct- 
ure indicative of free movements in the plastic mass. Of this class the 
basalts are typical among the basic rocks. The older rocks, on the con- 
trary, are completely crystalline, and in their microscopic structure are 


_ entirely granitic. These observations have led the German lithologists 
VOL. IV. 19 


146 MINERALOGY AND LITHOLOGY. 


to sub-divide their rocks into older and newer, and sharply to separate 
them in their nomenclature into two classes, according to their geologi- 
cal age, the tertiary being the turning point. This separation has been 
strongly opposed by some American and English geologists, and the ob- 
jection has been made good by proving that the distinctive characters 
are sometimes wanting where they should be found. Although the 
result of the discussion may be to eliminate the element of age from 
nomenclature, still the characters that distinguish old eruptive rocks 
from the newer ones are so very fundamental and so very general, that 
the value of these distinctions is recognized by every one. If, with this 
distinction in mind, one examines sections of our basic eruptive rocks, all 
the characters that are assigned to very old rocks are immediately recog- 
nized. They possess a crystalline structure that throws them into con- 
trast with younger rocks, and in their compositions and transformations 
they show all the effects of age. They do not come within the bounda- 
ries of the discussion before named, because geology and microscopy 
both would assign them to old formations. 

Of the basic eruptive rocks of this country, those that cut the Meso- 
zoic sandstone have been best studied. One vast series of dykes ex- 
tends up the Connecticut valley from the sound to the border of our 
state, and though they do not come within our boundaries, and hence 
are not within the limits of our descriptions, it is instructive to compare 
our rocks with a well defined American formation. We are indebted to 
Prof. J. D. Dana for most of our knowledge of these rocks, and Mr. E. S. 
Dana has examined them with the microscope. These rocks are essen- 
tially uniform in general appearance and in mineral composition wherever 
found, from Nova Scotia to Carolina. Some analyses made by myself 
indicate that their chemical composition is also almost invariable. Dia- 
base is the typical rock of the whole formation, varying only in the 
amount of hydration and alteration. Sometimes it is clear and undecom- 
posed, with scarcely a trace of hydrous minerals, and sometimes its con- 
stituents are all hydrated and decomposed, but in all cases it bears evi- 
dence of having been the same in original composition. These rocks 
were erupted after the accumulation of the Mesozoic red sandstones. 
Turning now from this grand uniform system to our old trap dykes, all 
this symmetry disappears. Not only do we find that there are varieties 


LITHOLOGY, 147 


representing all the stages of alteration and decay, but that the original 
rocks were most diverse, both in their mineral constituents and in their 
structure. Rocks which to the eye appear substantially the same, are, 
after microscopic examination, found to be widely separated from one 
another. Closely adjoining dykes, which at first glance would be as- 
sumed to be identical, prove to be very different; and this makes it plain 
that we deal with a complicated question. We find that these rocks can- 
not be regarded as forming any defined system, but that they are proba- 
-bly eruptions that took place at intervals during those long past ages 
when our rocks were accumulated and elevated, and owe their great 
diversity to variations in the underlying melted matters, in the condi- 
tions of eruption that obtained place at different periods, and to altera- 
tions produced in them by subsequent ages. Any effort now to sub- 
-divide them, and to refer different classes to different times, and to make 
geological systems of them analagous to the Mesozoic system, would be 
nearly impossible ;—therefore we must take them as a whole, as an old 
mass of basic eruptive rocks, and treat them all together. 

Not merely in physical and chemical properties do these rocks differ 
from the later eruptions. The Mesozoic trap rocks form, as a rule, large 
and conspicuous dykes. The scenery of the lower Connecticut owes 
much of its beauty to their high, overhanging cliffs, for trap rocks usu- 
ally make impressive scenery. So it is with the European basalts. They 
commonly stand in conspicuous masses above the surrounding region; 
and many often visited places are dependent upon basaltic rocks for their 
celebrity. But in New Hampshire all this is reversed. The trap rocks 
cut through old crystalline rocks, which, being very hard, are not more 
rapidly denuded than are the trap rocks, and hence the latter are not 
brought into prominence. In fact, more often the trap rocks, on account 
of their basic composition, are more easily decomposed and disintegrated, 
and hence, when they are brought into prominence, it is commonly in 
an inverse way; for, by yielding more readily to wear and decay, their 
removal from their position in the crystalline rocks forms gorges or 
flumes, many of which are celebrated for their beauty. Our trap dykes 
are, moreover, very often of such small size that in no case would they 
make striking features in the landscape. 

The first person who directed his attention to the trap rocks of New 


148 MINERALOGY AND LITHOLOGY. 


Hampshire was Prof. O. P. Hubbard, of Dartmouth college, who in 1837 
made a geological excursion through various parts of the state, and who 
made special observations on the eruptive dykes.* This gentleman rec- 
ognized clearly the great differences in these rocks, and noted the varia- 
tions in their appearance, even when situated side by side. But the 
means for careful discrimination being at that time beyond the reach of 
our science, all these rocks were classed together as trap. I hope that 
gentleman will not be displeased to know that some of his specimens, 
collected so long ago, have fallen into my hands, and that we now have 
the means for classifying them. 

Besides researches made on the rocks actually within our borders, 
more extended studies have been prosecuted on allied rocks in adjoining 
regions. The most prominent of the investigations are those prosecuted 
by Dr. T. Sterry Hunt, when connected with the Canadian survey.t The 
rocks which he studied and classified are nearly allied to ours, and in 
many cases identical. In reference to this work it may be said, that al- 
though microscopic study in many cases would, I think, cause a nomen- 
clature essentially different to be adopted, yet any new results which 
might by that means be attained would in no degree lessen the weight 
of Dr. Hunt’s reasoning in reference to the origin of this class of rocks, 
or any of his theoretical and geological conclusions, which must be what 
he chiefly values. The more essential features of Dr. Hunt’s work have 
been by him embodied in his Chemical and Geological Essays, a volume 
easily accessible to all, while the geological report is not. 

All our basic eruptive rocks are essentially compounds of triclinic feld- 
spar, with either hornblende or pyroxene, and, according to which of 
these latter minerals is present, they are divided into two classes. For 
the determination the microscope is often necessary, with the aid of 
which a number of accessory minerals are found, which are either essen- 
tial and constant, like magnetite and apatite, or accidental and variable, 
like chlorite, biotite, calcite, etc. The pyroxene or hornblende has at 
times been removed by process of alteration and decay; but still its orig- 
inal presence, and its influence in producing the structure observed, are 
so plain as to make no difference in the classification of the rock. The 


* Am. Four. Science, i, vol. xxxiv, p. 105. 
+ Geology of Canada, 1863. 


LITHOLOGY. 149 


hornblendic varieties are therefore all Dzorite, and the pyroxenic are all 
Diabase. 

When the feldspathic constituent is considered, subdivision is again 
necessary. Often any determination beyond the triclinic character of 
the feldspar is impossible on account of the decomposition, which has so 
nearly destroyed the crystals that only such little particles are left intact 
as suffice for the simplest optical examination; but, on the other hand, 
crystals are often found in such well preserved condition as to allow their 
species to be determined, and to prove that different species exist in dif- 
ferent rocks. In diabase, labradorite appears to be most common and 
most constant; but rocks are found in which anorthite becomes promi- 
nent and easy to determine. In diorite the feldspar is commonly plagi- 
oclase (either labradorite, andesite, or oligoclase), but cases where anor- 
thite is present are not wanting. 

Besides these general sub-divisions, varieties are produced by the 
prominent presence of accessory or variable constituents; and, aside from 
all mineralogical distinctions, there are very marked structural differences 
which sub-divide each species into compact and porphyritic varieties. 
There are, moreover, many varieties formed by degrees of alteration; 
but these are not recognized in classification, and the description of 
these rocks must consist, very essentially, of a history of change, reorgan- 
ization, and decay. It must be borne in mind that such rocks are pecu- 
liarly subject to change, for their mineral compounds are not very stable, 
and their bases are in part readily oxidizable. Expose such rocks there- 
fore to the influences of ages,—to the mechanical movements, change of 
temperature and condition that must have found place in the folded and 
contorted strata of our state,—and this diversity in present condition be- 
comes an interesting feature which might be expected to present itself. 

Besides the rocks mentioned, there is another basic eruptive rock, 
which in its structure and habit is so distinct, that, although composed 
of the same ingredients, and scarcely more than a variety of diabase, it 
may most advantageously be described by itself. This is Gadévo, which 
is considered last. 


DIABASE. 


Diabase is a crystalline granular mixture of augite with a triclinic 


150 MINERALOGY AND LITHOLOGY. 


feldspar, which is usually labradorite. An oxide of iron, in the form of 
magnetite or titanic iron, is always present, and usually, also, some green 
chlorite which has resulted from the decomposition of the other minerals. 
Numerous accessories are constantly or accidentally present. The rocks 
are gray, black, or green, according to the relative amount of the ingre- 
dients, and their condition as regards decomposition. Many of them are 
massive, but with us the larger part are more or less porphyritic. Al 
though varieties abound in which large and prominent crystals are devel- 
oped in a ground mass that is apparently very compact, still in no sense 
is this ground mass to be confounded with an amorphous or non-crystal- 
line body, for when magnified it is found to be entirely composed of 
crystals, and hence these structural differences are not of the nature 
to separate the porphyritic rocks from the others. Fundamental distinc- 
tions are formed by the introduction of anorthite in some cases, and of 
olivine in others. On these characters the group is sub-divided. 

Diabase (massive). Common massive diabase, as found in New 
Hampshire, is composed of a mixture of labradorite, augite, and mag- 
netite or titanic iron. It is nearly black when its ferruginous constitu- 
ents predominate, light gray when the feldspar predominates, and green 
when much chlorite is present. It varies in its texture somewhat, but is 
usually so fine that no ingredient can with certainty be recognized by the 
unaided eye. Its dykes occur in all parts of the state, but most abun- 
dantly in the mountainous regions. When its thin sections are exam- 
ined with the microscope, decomposition of one kind or another is found 
to have made extended progress, but the modes in which this decomposi- 
tion has progressed are very diverse, and have created quite distinct 
types of rock. 

Chlorite is the most prominent result of one common method of de- 
composition. In thin sections of these rocks a green chlorite is seen 
surrounding remnants of augite. The structure and general appearance 
of a section of this kind of diabase is represented in Fig. 1 on Pl. g. 
It is made from a green-colored rock taken from a dyke in East Hano- 
ver, and may be considered as a typical specimen of this variety. The 
augite crystals, at the expense of which the chlorite has been formed, 
were originally quite large, but now only little rounded grains are seen. 
In polarized light some of them are found to be twin crystals; in ordinary 


LITHOLOGY. Ist 


light their color is brownish red. The feldspar shows its characteristic 
bandings in polarized light, but is usually troubled and clouded by de- 
composition. The bandings are sometimes almost obliterated on account 
of alteration, and then the crystals do not become dark in any position 
between crossed Nicols, but show only the effects of an aggregate of 
secondary products. Crystals or grains resembling magnetite are found 
intact; but often a black rounded kernel or skeleton is found in a gray- 
ish mass, which is recognized as characteristic of the decomposition of 
titanic iron. Very minute needles of apatite, which pierce through the 
other minerals, and which are often grouped together in large numbers, 
are invariably present. Other products have also resulted from decom- 
position, a characteristic one of which is epidote. This is often macro- 
scopically seen filling amygdaloidal cavities, but is more often seen with 
the microscope, especially in sections that show a much altered feldspar. 
It appears as a very light yellow, slightly dichroic product, often in very 
minute particles which in polarized light assume the most brilliant colors, 
Calcite is rarely absent. It fills the cavities and pores, and, when not 
visible with the microscope, a specimen of the rock when moistened with 
acid will effervesce, and indicate its pressure. Biotite is not rare, but 
whether as an original or a secondary product is not certain. Quartz is 
not uncommon, but it is plainly a secondary product. These are the 
most general characteristics of the first well marked variety, which may 
be called the chloritic type. 

There are some large dykes of this rock on the road from the Glen 
house to the summit of Mt. Washington. In sections of specimens the 
double system of twinning, which so often characterizes labradorite, is 
conspicuous. A section of a specimen from Stark indicates that the augite 
is almost entirely gone, and chlorite takes its place, fills cavities in the 
rock, and forms little concretions in spots. A rock near the Sagamore 
house resembles the last, but in it much more epidote has been formed 
and less chlorite, and, as is usual in such cases, the feldspar has suffered 
more and the augite less. This rock also contains pyrites. A rock 
that forms a dyke which cuts the gabbro on Mt. Washington river is 
remarkable for its large content of pyrite and magnetite. The augite is 
in small grains, and has been altered in part into chlorite, and in part 
into hornblende. The decomposition of a light-colored diabase has 


152 MINERALOGY AND LITHOLOGY. 


formed Hitchcock’s flume in the Notch. In this rock the feldspar is 
much altered; the augite is entirely decomposed into chlorite and cal- 
cite, and the magnetite is in crystals. At Rye, a diabase occurs that 
combines almost all the peculiarities of decomposition that have been 
mentioned. It contains labradorite, augite, magnetite, and apatite as 
original constituents, and chlorite, hornblende, biotite, epidote, and calcite 
as secondary. It also contains pyrite, which is mixed with the magnetite. 
And thus we might go on, for every rock presents some variations pe- 
culiar to itself. The variations are, however, those of different propor- 
tion in the original constituents, and in the relative amount of decompo- 
sition products of the various kinds mentioned, and description becomes, 
therefore, the endless repetition of the same idea. 

The next most prominent variety of massive diabase which occurs in 
New Hampshire may be called mca diabase. The difference between 
this and the last variety was not originally great, but the mode of altera- 
tion has widened the gap between them. In this rock, the decomposing 
agencies have produced no chlorite of consequence, and hence the rocks 
are not green, but of a light gray color. In appearance they are as fresh 
as if crystallized yesterday. On being moistened with dilute acid they 
do not effervesce, and in looks and behavior quite surprise one who is 
looking for old weather-beaten rocks. But the microscope indicates as 
much alteration here as in the first case, for, on applying polarized light, 
what was originally augite is seen to be no longer a homogeneous min- 
eral, but an aggregate of minute crystals that resemble calcite.- On treat- 
ing the rock with dilute acid it does not effervesce; but if the acid is 
heated it effervesces long and powerfully, and in the solution lime, iron, 
and magnesia are abundantly found. This indicates the formation of 
dolomitic and ferruginous carbonates by decomposition, and makes it 
plain why the rock looks so fresh. The rock is quite feldspathic, and the 
feldspar is undecomposed, and its bands of color are clear and distinct. 
This fact, united to the circumstance that the augite is converted into 
carbonates, accounts for the light color and fresh appearance of the rock. 
The appearance of a section of a specimen from Bemis brook, in ordinary 
light, is represented in Fig. 4 on Pl. 6. Biotite is a characteristic mineral 
in this variety of diabase, and is very conspicuous in thin sections. It 
exists in little scales, which, when lying in the plane of the section, are 


LITHOLOGY. 153 


often seen to be hexagonal. Here and there in the mixture of carbon- 
ates a kernel of augite is found; apatite needles are very abundant; also, 
crystals of magnetite. Here and there a well formed crystal of horn- 
blende is seen, and also a bit of pyrite. The chlorite that is very spar- 
ingly present can be called nothing better than viridite, for it is in 
minute, formless bits, which in polarized light behave like an amorphous 
substance. 

As the feldspar is quite fresh and predominant in amount, an analysis 
of this rock may have some value as indicating its original nature. It is 
indeed interesting to note that with the complete destruction of the 
augite, the feldspar has so well maintained its identity. This rock from 
Bemis brook gave Mr. Pease, of the Sheffield Labratory,— 


Silica, ; - . ‘ ‘ . . ‘ ei é : 47 64 
Alumina, . : : ‘i ‘ : - z z : e , 18.35 
Tron sesquioxide, . 5 ‘ : . . z 5 ‘ 2 4.20 
Tron protoxide, 5 . ‘ ‘ a F a 5 A 5 6.52 
Manganese protoxide, . 3 ‘ 2 ‘ F 2 .16 
Lime, 3 2 ‘ 3 a . r F 3 F j : 7.08: 
Magnesia, é é ‘ é . . A i : . ‘ 4.36 
Soda, . . é a ‘ c a : . ‘ : 3-31 
Potash, . - 7 : F : : i : ‘ : 1.96 
Water, . 5 7 - : és 7 : 3 . : 5 2.33 
Carbonic acid, é é ‘ ‘ : ‘ 7 * é ‘i 5.01 

100.92 


The calculations on analyses of such heterogeneous mixtures are not 
very satisfactory, and if we allow at the highest twenty per cent. for car- 
bonates, iron oxide, &c., the silica is increased to sixty per cent., but as 
we know that silica that is liberated by decomposition is often present in 
such rocks in unrecognizable form, the probability that these are labra- 
dorite rocks is indicated. 

The variations in this variety of diabase are not wide. A specimen 
from Tripyramid mountain contains much more unaltered augite, but 
is otherwise the same. The Flume at Lincoln is made by the disinte- 
gration of a diabase identical with that from Bemis brook, save that it 
contains more iron oxide and pyrites, which aid its decomposition. A 


dyke at Dixville is the same, but more green chlorite has been formed, 
VOL. IV. 20 


154 MINERALOGY AND LITHOLOGY." 


and which has gathered into little radial concretions in cavities, which 
are otherwise filled with calcite (see p. 120). Some of the augite in this 
rock is quite fresh, and some is entirely decomposed. 

Diabase (Porphyritic). All the remaining varieties of diabase that 
have been found in New Hampshire are porphyritic; and though many 
are massive, the development of large crystals in a ground mass of fine 
crystals is much more characteristic of the basic eruptive rocks of the 
state. Sometimes but one ingredient is porphyritically developed; and 
sometimes nearly all the constituents are in part large crystals. The 
ground mass is in no sense an amorphous or half crystalline substance, 
but is a fine-grained diabase; and therefore the difference between the 
massive and porphyritic varieties is merely a structural one, which is 
dependent on certain conditions which I shall endeavor to point out. 

The most common variety of porphyritic diabase is the one in which 
large crystals of labradorite are developed in a fine-grained ground mass. 
The rock is ordinarily called labradorite porphyry. With its large white 
crystals so conspicuous in their black surroundings, it is very beautiful. 
This feldspar is often perfectly fresh and undecomposed, and thin cleav- 
age pieces can be obtained, the optical properties of which prove the 
crystals to be labradorite. The angle between a plane of elasticity and 
the twinning plane, as measured in basal cleavage scales obtained from 
specimens from Ossipee and Center Harbor, is about seven degrees. 
The specimen from Ossipee will be described as typical. In thin sec- 
tions, the augite in the ground mass is seen to be altered into an aggre- 
gate of chlorite, calcite, etc., while the large and small crystals of labra- 
dorite are still intact. Two systems of twinning are often seen in the 
large crystals, which show very clear and distinct bands of color in 
polarized light. The other constituents and peculiarities of the rocks 
are those of common diabase, and which need not be repeated. Speci- 
mens from Center Harbor, and Concord, Vt., have been examined, and 
offer no further peculiarities. A specimen from Bartlett contains some 
quartz. In all the specimens the large crystals are flat and tabular, and 
hence on surfaces of fractures they appear long and narrow. This is 
because the lateral planes of the crystals are developed, but none others. 
The terminations of the crystals, as seen in the rocks, are consequently 
irregular. 


LITHOLOGY. 155 


Some sections of the labradorite porphyry from Ossipee present a 
most interesting phenomenon. Many of the large crystals of labradorite 
are seen to have been all broken up after they had been formed, and then 
cemented together again. Fig. 2 on Pl. g represents one of these crys- 
tals. In this crystal, the bandings of color that are induced by polarized 
light are dislocated and out of joint, while below are pieces which have 
evidently been broken off. Other crystals in this section have been all 
broken up into a complete mass of fragments, and then all cemented 
together again. It appears in this case that the large crystal had grown 
to its full size before the mass had solidified, and at some given time a 
movement or commotion took place which broke into fragments many of 
the crystals that had been formed, and induced at the same time some 
change in condition, which caused quicker cooling and the solidification 
of the residue of the matter in little crystals. A sudden change of con- 
dition is, then, one cause which results in the production of porphyries. 

Anorthite Diabase. The diabase of New Hampshire, in which anor- 
thite has been proved to enter as an essential, is also porphyritic. The 
reasons why it should be so are of a different nature from those just 
referred to for the explanation of the structure of labradorite porphyry. 
The essential ingredients of common diabase do not widely differ from 
one another in fusibility; but anorthite fuses with difficulty, and hence, 
if it is to be formed in a mass cooling from a state of fusion, its crystals 
will have the first opportunity to grow; and where it is found in such 
rocks in our state its crystals are quite large and well formed. When 
sections are examined with polarized light, these crystals are found to be 
more or less completely altered into an aggregate of fibres, but a well 
defined centre is often left intact.. The ground mass is usually coarser 
than that of the labradorite porphyries. A good example of this rock 
is found at East Hanover, in a series of small dykes that intersect the 
slaty rocks. The anorthite is in crystals as large as hickory nuts, pos- 
sessing quite a variety of planes (see p. 90), although these planes are 
quite rough, as might be expected in such surroundings. The crystals 
are commonly altered into a translucent, waxy substance, which, as al- 
ready stated, is a mere aggregate of fine needles, and is called saussurite ; 
but often crystals with clear and undecomposed centres are found. The 
appearance of a thin section of one of these crystals is represented on 


156 MINERALOGY AND ‘LITHOLOGY. 


Pl. 5 in Fig. 3. The rock contains augite of a light pink color, much 
green chlorite, and a little biotite. The iron oxide is titanic iron, and 
its solid centres are usually surrounded by a gray, translucent rim. Apa- 
tite is abundant. 

The massive portion of this rock has been analyzéd by Mr. Pease, of 
the Sheffield laboratory, with the following result: 


Silica, ‘ ‘ a . r 2 ‘ a . g - 47.38 
Alumina, és s ° s é . 5 ‘ - F é 19.08 
Tron sesquioxide, . ‘ _ . a ‘. * < ‘ : 2.66 
Iron protoxide, : ‘ , 5 ’ . 3 a A ‘i 8.81 
Lime, . ‘ : : . 5 2 - , 2 F : 8.37 
Magnesia, 5 . . : . 7 ‘ c 4 . 5 6.07 
Soda, : : : . 3 ‘i 5 3 A 5 ‘ ‘ 3-54 
Potash, . 3 ; 3 z ‘ 2 . 3 o 6 F 1.31 
Water, . . * ‘ ‘ a E : ‘ 7 . 3-39 
Carbonicacid,. . . @ : ‘ i ‘ c - 5 79 

101.40 


Specific gravity, 2.go. 


An analysis of the anorthite from this rock has been given on page 91, 
which indicated the ‘composition of the aggregate into which the large 
crystals have been converted. But the feldspar in the compact part of 
the rock is not so altered as are the large anorthite crystals; and the 
analysis points towards a soda lime feldspar like labradorite, and makes 
it probable that two kinds of triclinic feldspars are present, as has often 
been proved to be the case elsewhere. 

A specimen from Moose Mountain, and another from Stark, offer no 
further peculiarities, save the presence ih them of much pyrites. A 
specimen from Concord, Vt., contains much calcite, and 'the anorthite is 
almost entirely altered into ‘an aggregate. 

Besides the occurrences of diabase porphyries that have been men- 
tioned, there are a great many others in which the feldspar has reached 
such a state of decomposition that neithér analysis nor the microscope 
can determine its species. In regard ‘to all these, it may be said, that 
whether originally labradorite or anorthite is ‘now of little consequen¢e, 
since time has reduced one and the other to the same thing, and for such 
rocks porphyritic diabase is a name sufficiently satisfactory. It may ‘be 


LITHOLOGY. 157 


said of those specimens which have been determined, that the anorthite 
varieties have crystals that are short, thick, and well defined in outline, 
while the crystals of labradorite are long and irregularly terminated. 
If this should be regarded as characteristic, both varieties are present 
among these more decomposed rocks. 

Olivine Diabase. Ever since Prof. O. P. Hubbard found the remarka- 
ble boulders of this rock at Thetford hill, those interested in them have 
been hoping to find the rock in place. The employment of the micro- 
‘scope brings these interesting rocks to light, and the specimens, though 
not so remarkable when examined with the unaided eye, are, when cut 
into sections and magnified, found to be very interesting and beautiful. 

The boulders found at Thetford hill are composed of large round 
masses of olivine sometimes two inches in diameter, large rough greenish 
plagioclase crystals, and large black augite crystals, all embedded in a 
small amount of a ground mass. Dr. Hunt has described a rock exactly 
like this, which is in place at Montarville, in the neighborhood of Mon- 
treal, From whence these boulders came is not known. 

Olivine bearing diabase is not a common rock, though it seems quite 
plain, as Mr. Rosenbusch remarks, that microscopic studies will much 
increase the number of its representatives. As found in dykes at Camp- 
ton falls, it is a black porphyritic rock. The macroscopic crystals are jet 
black, and with the unaided eye it would be hard to say whether they 
were of augite or hornblende, as they are not large, and show no distinct 
cleavage. They have, however, very well defined outlines, indicating a 
good crystallization. The olivine is not distinguishable as such, and the 
reason becomes very plain when the sections are studied: it is because 
they are no longer olivine. In the thin sections, we see that in a compact 
and very fine mixture of crystals'of a triclinic feldspar, augite, biotite, horn- 
blende, chlorite, and magnetite, are larger and well formed crystals of a 
triclinic feldspar, augite, and olivine. The olivine is very well crystal- 
lized, and a section through two of its crystals is represented in Fig. 4 on 
Pl. 7. This olivine is all much altered. The centres of the crystals are 
in some places intact, but most of them are entirely changed into a 
greenish-fibrous serpentine-like mineral—a kind of alteration to which 
olivine is peculiarly liable. The augite is quite abundant, and its large 
crystals are perfect.in ‘outline, but the fine augite scattered through -the 


158 MINERALOGY AND LITHOLOGY. 


ground mass is without crystalline form. The rock contains many 
microscopic cavities, which are filled with a quite complex mixture of de- 
composition products. The outer walls of the cavities were first lined 
with sphaerosiderite, then there was a growth of hexagonal calcite crys- 
tals, and finally the cavities were filled with analcite, the peculiarities of 
which have been described in the mineralogical chapter. 

Another specimen of this rock, also from Campton falls, offers some 
other interesting microscopic peculiarities. The external appearance of 
the rock is the same, but decomposition has produced substances of 
different aspect. The chlorite in the ground mass is replaced by a dull 
white translucent substance, which is probably carbonate of lime, and 
the cavities filled with minerals are absent. The large crystals are con- 
centrically banded, the different zones resulting from some differing 
conditions at stages of their growth, and from subsequent alteration. 
The plagioclase crystals have impurities heaped in their centres, while 
on the outside the crystals are clear. The augite is in zones, which 
differ but slightly in their color, but which are brought into stronger 
contrast when polarized light is employed; for when the Nicols are 
crossed and the section is revolved on the stage of the microscope, the 
different bands do not become black at the same time, which shows that 
the planes of elasticity in the different parts of the crystal take slightly 
different directions, and therefore, whatever be the position of the Nicol 
prisms, the crystal sections are banded with different colors. These 
augite crystals are represented in Fig. 3 on Pl. 9. The crystals of olivine 
are also quite peculiar in their mode of decomposition. They are 
affected to their centres, yet the cores have still, in polarized light, the 
optical behavior of crystals, though the clear color usual to olivine is 
mottled by decomposition products. Next to the centres are radiated 
fibrous masses of serpentine which give beautiful green colors between 
the Nicol prisms, but the outsides of the crystals have been apparently 
entirely removed, and the spaces filled with a mixture of calcite, quartz, 
and pyrite. The pyrite is in cubes, and some of the crystals have 
dodecahedral planes. One of these crystals of olivine is shown in Fig. 
4 on Pl.9. This is simply another form of the alteration which con- 
stitutes so large a part of the study of our basic eruptive rocks. 

T call attention here to the fact that the gabbros, which are described 


LITHOLOGY. 159 


later, are very nearly related to diabase, and, indeed, may well be classed 
as varieties of it. They have, however, such distinctive characters that 
I do not like to introduce them here between rocks which are more in 
need of classification. 


DioriTtz (PoRPHYRITE). 


Diorite is a crystalline, granular mixture of a triclinic feldspar, horn- 
blende, and an oxide of iron, which is either magnetite or titanic iron. 
There are in New Hampshire two well defined and very distinct kinds of 
diorite. One contains a green, more or less fibrous, hornblende, and also 
often contains quartz, which at times is present in such amounts as to 
relate the rocks to the amphibolites in composition. The rocks are light 
green in color, and though massive their beds are arranged conformably 
with the surrounding strata. Such rocks in Canada have been shown by 
Dr. Hunt to be sedimentary beds metamorphosed into diorites. The 
conformity of rocks of this nature at New Haven with the surrounding 
strata has been clearly shown by Prof. Dana; and others have followed 
in their studies upon rocks of various regions. The diorites of the other 
class are in New Hampshire black rocks. The hornblende that they 
contain is in compact grains, or in crystals with defined outlines. It is 
not green, but is black, and in thin sections it is deep brown or dark 
yellow, and is strongly dichroic. The rocks of this nature occur in well 
defined dykes cutting through the strata, and are plainly eruptive. It 
is understood that, in this place, we are treating only of the latter class; 
the former are described among the greenstones of the Connecticut 
valley. 

These rocks sometimes resemble diabase, and though in those that 
contain large crystals the hornblende can be recognized by its cleavage, 
in the more compact varieties this is not possible. A glance with the 
microscope is, however, sufficient for their determination; and the neces- 
sity for careful discrimination by such a method becomes very evident 
when it is found that dykes of diorite and diabase are situated side by 
side, specimens from which could with difficulty be distinguished from 
one another. Being so associated, little room is left for generalization 
upon their relationship to one another as regards position. The micro- 


160 MINERALOGY AND LITHOLOGY. 


scope reveals the frequent presence of the same accessory ingredients, 
such as biotite, apatite, chlorite, pyrite, and calcite. 

The study of these rocks leads us through the same channels as be- 
fore. We have to consider wide differences in the composition of the 
original rocks, and wide differences that have resulted from the decay 
which long ages have induced. It may be stated, however, that the dif- 
ferences in the original compositions of our diorites are greater than of 
our diabases, while the more stable nature of hornblende has preserved 
the diorites from such universal alteration as characterizes our diabase. 

Diorites may originate from an alteration of the augite of diabase into 
hornblende, or from the original crystallization of hornblende. Mr. Al- 
port states, that the first process of formation is quite general in the 
English rocks at Landsend, and that all stages of the process of change 
are easily found. I have spoken of incipient change of this kind in de- 
scribing certain kinds of diabase; but our eruptive diorites usually con- 
tain microscopic or macroscopic hornblende crystals, which are quite 
well crystallized in the form characteristic of the species,—and hence we 
are dealing in this respect with primary formations. 

Our diorites, being mostly porphyritic, belong to the class of rocks 
which, by some Germans, are called porphyrite. I think no one will ob- 
ject to the simple inversion of their terms which I employ. Porphyritic 
diorite means the same as diorite porphyrite. The ground mass of 
these porphyritic diorites is wholly crystalline, and though large crystals 
are developed in it, it is diorite still. 

There seem to be two quite distinct types of this rock in New Hamp- 
shire, one of which is very basic in composition, and only hornblende is 
porphyritically developed in it, while the latter contains more silica; and 
both hornblende and plagioclase are conspicuously developed in the 
black compact ground mass. The first variety contains a triclinic feld- 
spar, which cannot be identified with any certainty, and we will call the 
rock merely basic diorite. The second variety contains andesite or oligo- 
clase, and we will speak of it as plagioclase diorite. 

Basic Diorite. (Porphyritic Diorite.) This is a rock which has for a 
ground mass an aggregate of crystals of triclinic feldspar, hornblende, 
biotite, and magnetite or titanic iron, with usually some chlorite and 
apatite. In it well formed crystals of hornblende are developed, and at 


LITHOLOGY. 161 


times quite large crystals of titanic iron. Under the microscope, with 
polarized light, feldspar crystals of some size are seen, but they are so 
impure that they can scarcely be distinguished from the ground mass 
without polarized light. In some specimens, however, they are pure 
enough to see all their bandings; and in appearance and mode of decom- 
position they much resemble the anorthite of the diabase, and are en- 
tirely unlike the feldspar of the diorites next to be described. At Camp- 
ton falls there are several dykes which furnish handsome specimens for 
those who admire dark, porphyritic rocks. The black crystals of horn- 
blende are not large enough to determine with the unaided eye, but they 
are very brilliant and numerous. The following analysis made by Mr. 
Pease, indicates the general composition of this rock: 


Silica, . a F C 5 . a a 3 , : F 43.39 
Alumina, i . * . . . a ‘i . 5 . 15.85 
Iron sesquioxide,  . . F . . z : ‘i a 3 6.56 
Iron protoxide, . 5 a : . z ‘ , - 9-51 
Lime, z ; F C 5 . 3 3 % . . : 9-47 
Magnesia, P ‘ i = ‘ e ‘ : is ‘ 5.01 
Soda, : ‘ “ ‘ F : . , - é . 5-15 
Potash, “19 
Carbonic acid, 5 . . ‘ 5 . 5 : : . 2.47 
Water, 3-29 

100.89 


This analysis is interesting as showing the very basic nature of these 
rocks, but beyond that, little can be deduced from it, though it may be 
suspected that the feldspar is basic too; but the predominance of horn- 
blende, the presence of much magnetite or titanic iron, and the compli- 
cated nature of the rock, leave any conclusion that may be drawn only 
probable. 

When examined under the microscope, beyond the general character- 
istics of the rock already mentioned, some interesting details are brought 
to view. The hornblende crystals are deep brown when the light passes 
through them in one direction, and bright yellow when it passes at right 
angles thereto. They are often twins, the twinning plane being parallel 
to the orthodiagonal. Moreover, some of these crystals are hollow, and 


the cavities that they contain have a contour like the exterior, and are 
VOL, IV. 21 


162 MINERALOGY AND LITHOLOGY. 


filled with the same aggregate of minute crystals as that which forms 
the ground mass. This enclosure of material is usually indicative of rapid 
growth. A section of a crystal of this nature is shown in Fig. 5 on Pl. 9. 
It is drawn as it appears in ordinary light, and even there the twinned 
sides of the crystal can be distinguished from one another by a slight 
difference in their shade. To the left of the large crystal is a hexagonal 
crystal, probably of titanic iron, though such a section could be cut from 
a dodecahedron of magnetite. Mr. Zirkel, when he found crystals ex- 
actly like these in the basalt of the Lacher See, supposed them to be of 
titanic iron. Inside the hornblende crystal, a crystal of this iron oxide 
of some size has developed among the other finer ingredients of the rock. 
With the aid of polarized light, the clear spots in the base are found to 
be feldspar crystals, the outlines of which are hidden in the ground 
mass. Some clear spots are cavities filled with calcite, and which 
evidently were formed by the rotting away of some mineral. 

In another specimen from Campton falls the feldspar becomes more 
prominent, and the rock consequently lighter in color; the mica de- 
creases in quantity, and fine crystals of hornblende take its place in the 
ground mass. This ground mass is so coarse as almost to destroy the 
porphyritic character of the rock. Apatite needles are abundant, and the 
iron oxide appears to be crystallized magnetite. 

A specimen of diorite, from boulders in North Lisbon thought to have 
been derived from dykes cutting porphyritic gneiss, shows the interesting 
feature of the well defined outlines of hornblende and augite crystals 
associated together. They were plainly simultaneous and original for- 
mations. This rock contains more feldspar, and the ground mass is con- 
sequently quite light in color, but the feldspar is so decomposed that in 
thin sections it is only translucent, and its optical properties are obscure. 
Embedded in this coarse ground mass, black hornblende crystals are 
prominent, and in thin sections they appear to be perfectly fresh and 
undecomposed, and in part very well formed. The augite which first 
becomes visible when the microscope is employed was originally very 
perfectly crystallized, but now it is nearly all decomposed, and its place is 
filled with an aggregate of epidote, calcite, chlorite, &c., but still some of 
its original structural lines are preserved in the new products, and some 
crystals still possess an augite core. One section that I have examined 


LITHOLOGY. 163 


is particularly interesting. A crystal of augite and one of hornblende 
lie united together, with their prisms parallel to one another, and the 
section is so cut as to intersect the prisms in a plane parallel to their 
bases. This section is represented in Fig. 6 on Pl. 9. Though the out- 
lines of both the crystals are very perfect, they are united together by an 
irregular line. The hornblende crystal is entirely fresh, but the augite 
is decomposed and dissolved away, and its place is now filled with 
decomposition products. But among the chlorite, epidote, and calcite 
are some fragments of hornblende which are indeterminately situated, 
and perfectly angular and fresh. They must have dropped into the cav- 
ity made by the decay of the augite crystal, from the irregular edge of 
the hornblende crystal, at a time when the space was partially empty, 
and have been subsequently enclosed in the new products. No other 
space originally filled with augite contains any hornblende, with the ex- 
ception of this one where the crystals lie together, and the irregularity 
of the edge of the hornblende would make it easy to derive such frag- 
ments from it. This section furnishes a very pretty illustration of the 
stability of hornblende as compared with augite, and was one of the cases 
which was in mind in the discussion of the chemical differences between 
these species when associated. 

But in this kind of diorite the hornblende does sometimes entirely 
decompose. We will next consider a case of this kind. Near the Pro- 
file house there is a dyke of black rock, which, on being examined with 
the microscope, proves to be a diorite which originally had well defined 
crystals of hornblende; but now the spaces bounded by the crystalline 
outlines of hornblende are filled in most cases with a heterogeneous 
mixture of biotite, magnetite, and calcite, while occasionally’'a centre of 
dirty-green hornblende is still preserved. At other, times, only magnet- 
ite and calcite are seen; and in the aggregate the cleavage directions of 
the original mineral are indicated by clearer spaces through the turbid 
mass. The rest of the rock is composed of an aggregate of crystals of 
hornblende, biotite, chlorite, plagioclase, calcite, and magnetite. A sec- 
tion through one of the hornblende crystals is shown in Fig. 3 on Pl. ie 
and another in Fig. 3 on Pl. 2. Externally, this rock has lost the porphy- 
ritic appearance that characterizes most of our diorites, and the reason is 
self-evident. 


164 MINERALOGY AND LITHOLOGY. 


Plagioclase Diorite. (Porphyritic Diorite.) There is another kind of 
diorite, which has been found in boulders scattered all over New Hamp- 
shire, and which is in place in the Dixville Notch and at other points in 
the northern part of the state. This diorite is characterized by the por- 
phyritic development of all its ingredients; but large grains, which are 
sometimes an inch and a half in diameter, of a clear white, glassy feld- 
spar, are particularly conspicuous. This feldspar is in condition for 
accurate determination, and proves to be a variety of plagioclase; and 
hence this diorite can be more definitely classified than the others thus 
far described. The feldspar is very striking in appearance. At the first 
glance it looks like quartz, for, in some directions, its fracture is vitreous, 
but on examining further, in other directions, bright cleavage faces are 
identified. In composition, it is near andesite, and its analysis has been 
given under that head (see p. 96). In polarized light few bands are 
found, for its separate laminz are quite broad. Its optical properties 
are those of oligoclase, and, according to Des Cloizeaux, andesite is 
identical with oligoclase. I call the diorite, plagioclase diorite, because 
a variation no greater than what is very liable to occur would make this 
feldspar labradorite or oligoclase; and the members of the class of plagio- 
clase diorites are subject to variations which embrace this sub-species. 
The hornblende of this rock was also analyzed. It was found to be 
quite aluminous. The magnetite is also porphyritically developed; and 
even the apatite is macroscopically visible in long, slender, clear needles, 
which pierce indiscriminately through all the other ingredients. The 
ground mass of this rock is an aggregate of the same constituent. The 
strong contrasts between the bright black and clear white crystals, and 
the dark, compact ground mass, make this one of the most striking rocks 
that occur in our state. 

When microscopically examined, this andesite is found to be fresh 
and clear, and in polarized light shows no effect of decomposition. In 
this respect it is almost isolated among our basic feldspars, and furnishes 
a good illustration of the greater power of a glassy mineral to resist 
decay; but in a specimen of this rock from Dorchester, in which the crys- 
tals are very large, all the minerals are much altered, and epidote becomes 
a prominent ingredient of the rock. 

Another diorite at Dixville is worthy of mention. This rock cuts the 


LITHOLOGY. 165 


slates, and on fresh fractures it is red. This color results from the sepa- 
ration of iron oxide. The rock is porphyritic; but many crystals have 
rotted away, and the stone is now full of cavities containing calcite. 

Mica Diorite. A diorite in which biotite replaces hornblende occurs 
at Stewartstown. This is not a porphyritic rock, and, in addition to its 
triclinic feldspar, which is probably anorthite, and its biotite, it contains 
much calcite, and also some magnetite, pyrite, apatite, and chlorite. Some 
such calcareous rocks were called hemithrene by Brongniart, but the 
term is now obsolete; and the rocks so called are referred to diabase 
and diorite, to which their nature and composition most closely relate 
them. This specimen of diorite is rather different from all others col- 
lected in the state, and whether it is an original product, or a result of 
decomposition, is questionable. 


GaBsBrRo. 


This rock in its mineral constituents is closely related to diabase, from 
which our varieties are distinguished not only by the circumstance that 
the pyroxene is of the foliated kind which is called diallage, but also by 
their coarse granular structure, which in its details is much more like 
that of granite than that of the diabase that has been described. 

Gabbro is found in immense masses in Waterville, and in the vicinity 
of Mt. Washington. The relationships of its masses to the surrounding 
strata are not so easily determined as are those of the little dykes of dia- 
base and diorite, the walls of which are usually plainly seen; but at some 
points the rock possesses all the structure of an eruptive mass, and when 
in other places this is not found, the evidence furnished by more favor- 
able localities, as well as that furnished by allied rocks in other lands 
where they have been more thoroughly investigated, must at present be 
decisive. : 

Our gabbros are coarse granular mixtures of labradorite, foliated augite 
or diallage, olivine, and magnetic or titanic iron. Apatite and biotite are 
the constant accessories. Hypersthene is sometimes prominent, and 
sphene, chlorite, and pyrites are often present. The first four ingredi- 
ents are macroscopically conspicuous, and the rest are identified in thin 
sections. The prevailing color of the rock is dark gray, but it varies 


166 MINERALOGY AND LITHOLOGY. 


with the proportion of the ingredients from light gray to black. Future 
search will certainly bring to light many more varieties of this rock than 
I have to describe, for the regions in which these rocks are found are 
strown with boulders which are composed of varieties of gabbro, which 
it would be a pleasure to investigate if their source were accessible. 

In Silesia, and in some other regions, mountains and cliffs composed 
of gabbro are conspicuous in the landscape. Owing to their smaller 
bulk, and the condition of the surrounding strata, this is not the case in 
New Hampshire; but as lithological specimens, they are no less interest- 
ing. There are some general differences between the specimens from 
our two localities where this rock is found in place. We will first speak 
of the gabbro from Waterville. 

As here found, the rock is very coarse in texture, and nearly black. 
The feldspar is dark in color, and possesses bright cleavage surfaces on 
which fine striations are very conspicuous. In regard to the chemical 
and microscopic properties of its individual minerals, considerable has 
already been said. Analyses of the feldspar and olivine, by Mr. E. S. 
Dana, have been given on pp. 93 and 7o. These analyses show that 
the feldspar is labradorite rich in lime, and that the olivine is a variety 
very rich iniron. The diallage, though apparently black, is in thin sec- 
tions, of a pinkish color. This mineral, in many typical gabbros, when 
cut and examined with polarized light, presents a very fine fibrous struct- 
ure. This is not seen in the diallage of our rocks, and neither is it at 
all an essential feature, since the ready separability of the augite into 
laminze is the characteristic of diallage, and the fibrous nature of the 
mineral in thin sections is only characteristic of occurrences from certain 
localities. The augite of our rocks is like that of the variety that has 
been called palatinite. This name was given by Laspeyres to a gabbro 
of carboniferous age, which is abundant about the Pfalz on the Rhine, 
though varieties from other regions have since been embraced in the 
name. This gabbro, however, is not entirely crystalline, but contains 
more or less of glassy matters which are not found in our rocks. The 
unessential nature of the distinction between diallage and augite, and 
the identification of all the intermediate structural varieties between the 
most typical specimens of the two minerals, makes more forcible what 
was previously said in regard to this rock,—that when strict rules are 


LITHOLOGY. 167 


applied it can only be classified as a variety of diabase. This is the 
opinion of Mr. Rosenbusch, and other eminent lithologists. 

Fig. 1 on Pl. ro represents a magnified section of this rock as it ap- 
pears in polarized light. The diallage possesses peculiar outlines, owing 
to the influence of the feldspar upon it. These crystals crowd upon it, 
often pierce through its margin, and sometimes a rectangular feldspar 
crystal is wholly enclosed in the diallage. Hypersthene is recognized 
by its orthorhombic behavior in polarized light, and by its peculiar inter- 
positions, which are arranged in three definite planes (see p. 54). The 
olivine is yellowish-green, and in thin sections it is light yellow, and being 
fresh and undecomposed it gives very brilliant interference colors when 
examined with polarized light. As usual, it is traversed by irregular 
rifts, which are made very prominent by the black stains caused by 
beginning decomposition. It is often impure on account of the enclosed 
magnetite. The black grains of iron oxide are very abundant in this 
rock. It is not crystallized, and in part at least is very magnetic; and 
as it has been shown by Mr. Dana that it is quite titanic, it is a titanic 
magnetite. In some grains of this magnetite I once found some little 
specks of metallic iron. Dr. J. Lawrence Smith, to whom I gave some of 
the rock, also found some; but it is not easy to find it when one seeks for 
it, and it may have resulted from the accidental reduction by some car- 
bonaceous material that came in contact with the oxide when it was hot, 
and may be very local, and not widely distributed through the rock. If 
this is so, it has no special lithological significance. 

The labradorite is very white and clear in thin sections, although it is 
filled with impurities. It contains numerous grains of augite and magne- 
tite, scales of biotite, and crystals of apatite, and sometimes innumerable 
minute needles run in several well defined directions through it. These 
needles are common in the labradorite of gabbros. They were described 
on page 94, and Fig. 5 on Pl. § represents them. The labradorite in 
polarized light is banded with the most brilliant colors; but, as indicated 
in the figure, the exact parallelism of the bands does not extend over any 
great width of the grains. 

The apatite is microscopic, but some of its crystals are quite large. 
They exhibit most interesting peculiarities. Sometimes little crystals, 
or crystalline forms of darker color, are arranged in their interiors, with 


168 MINERALOGY AND LITHOLOGY. 


their axes and sides parallel to the crystal that encloses them: Some 
crystals are filled with cavities which are apparently empty; and the 
sides of many of the crystals are eaten through as if by some reagent. 
Sometimes only the margin is attacked, and sometimes three quarters of 
the crystal is eaten away. Some of these crystals are represented in 
Fig. 6 on Pl. 8. The apatite was the first mineral to crystallize in the 
rocks, since its position was apparently taken independently of the other 
minerals. These etched crystals are explained on the supposition that 
after the apatite had crystallized from the cooling mass there was a 
return to former conditions, whereby the apatite was again partially de- 
stroyed. The perfect crystals may have formed subsequently. 

Of accessory constituents, biotite is the most common. It is very 
dark in color, and very dichroic. A grain of sphene is occasionally met 
with. Serpentine and chlorite are sometimes present as decomposition 
products in superficial specimens. 

One very peculiar'rock forms a bed of some magnitude in the neigh- 
borhood of the Waterville gabbro. It is a coarse-grained rock, light in 
color, and resembles diorite. Its feldspar was analyzed by Mr. Dana, and 
shown to be labradorite, but all the minerals that form the rock are much 
altered. When thin sections are cut from this rock, all the ingredients of 
the gabbro are found as cores of the decomposition products, with the 
exception of the olivine, which is more easily altered, and which is com- 
pletely changed into green serpentine. The unaltered remnants are 
identical with the minerals of the rock just described; and the very 
peculiar and striking appearance of this rock is due to the strong con- 
trast into which the minerals are brought by decay. The originally black 
labradorite has become opaque white; the black diallage is light brown, 
or green; but the magnetite maintains its old form and lustre, and the 
apatite is also intact. The presence in the apatite of its very marked 
peculiarities, which render it so interesting, points conclusively to the 
circumstance that this is only a form of gabbro which has resulted from 
decomposition. 

The masses of gabbro that occur on the Mt. Washington river present 
only minor variations. The rock occurs in immense masses that are best 
exposed on the borders of the river-bed. It is lighter in color than the 
Waterville rock, because it contains more labradorite and less magnetite. 


LITHOLOGY. 169 


Its feldspar is also labradorite, as shown by an analysis by Prof. Blanpied, 
of Hanover (see p. 93). I have not found any hypersthene in it, and all 
the constituents are in smaller crystals or grains. 

In going up the Mt. Washington river to observe this formation, one 
is obliged to progress in the bed of the stream by springing from rock to 
rock, since the woods are so thickly undergrown that they can with diffi- 
culty be traversed. If one stops to look at the rocks on which he steps, 
I think he will be struck with the variety of interesting specimens of 
gabbro which AWE been brought down by the stream, and lie scattered 
along its course.’ The stream in the spring time is a rushing torrent, and 
rolls along large boulders. The region up this stream has not yet been 
explored by a lithologist; and I think that a careful search of it would 
enable one to collect a series of specimens of gabbro that would equal 
in interest those from any one of the celebrated European localities. 
Many water-courses and boulder-covered fields in New Hampshire pre- 
sent a most diversified cabinet of lithological specimens, but which lose 
their present value because their origin and sufroundings are unknown. 
Many may have travelled long distances, and many may be in place near 
by; but the observation of these boulders is of interest to the student 
as indicating the possibilities of our future lithology. 

There are two or three kinds of boulders which ought not to be en- 
tirely passed by, because they have attracted much attention and are 
widely known, and they may naturally be mentioned here. In and about 
Gilford are many boulders of a beautiful variety of gabbro, in which the 
large, foliated grains of diallage are round in form, and spot the rock in 
such a way as to make it very beautiful. Thin sections under the micro- 
scope show that this diallage is partially altered to hornblende. A chem- 
ical examination indicates that the feldspar is anorthite. Our country, 
which has furnished thus far few gabbros, certainly possesses a most in- 
teresting and beautiful one, which this represents. 

The labradorite boulders in Stark are very well known, and many peo- 
ple have taken specimens from them. Though found in no other place, 
they are there so abundant that some have thought they must be in place 
near by. I have some thin sections cut from these rocks. They are es- 
sentially composed of labradorite. The interspaces between the crystals 


of this mineral in most of the rocks are filled with hornblende, biotite 
VOL. Iv. 22 : 


170 MINERALOGY AND LITHOLOGY. 


magnetite, pyrite, and sphene. The rocks are therefore allied to diorites. 
The interspaces in another section are filled with an entirely different 
substance, which probably is a very impure pyroxenic mineral, too 
opaque, even in the thinnest sections, for determination, Dr. Hunt told 
me that these rocks were about identical with his norites; and, as the 
microscopic examination presents no objection to this, it cannot be said 
that these rocks were not brought from the great Norian formations in 
Canada described by Dr. Hunt. 


* * * * * * * * * 

Remarks concerning basic eruptive rocks. Looking backward now at 
the general nature of our basic eruptive rocks, there are a few conclu- 
sions to be drawn which are not only instructive in reference to them, 
but are also helpful in our study upon the classes of rocks which are 
hereafter to be considered. 

It is to be noted that there are wide differences in them, which are 
of three kinds. The first results from a difference in the composition of 
the original mass; the second is a difference in structure; and the third 
is a difference due to alteration and decay. We will briefly consider 
these differences and their causes. 

First: in regard to difference in original composition. Eruptive rocks 
are derived from those layers of fused and liquid rock materials which 
underlie the earth’s cold crust. It was long supposed that the whole 
earth was molten and fluid, with the exception of the crust, and that rifts 
in this crust gave passage to the molten materials that were beneath it, 
and which had never been solidified. The demonstration by Hopkins, 
that solidification induced by pressure began at the centre, and that the 
unsolidified zone of the earth is one which lies between the core solidified 
by pressure and the crust solidified by cooling, introduced some new feat- 
ures, since, as shown by Scrope, portions of the earth once solidified 
might become again fluid on account of movements in the earth’s crust 
and the transportal of sediments, resulting in the derangement of the 
balance between the two elements which determine the position of the 
fluid zone. Scrope, Scheerer, Elie De Beaumont, and others have held 
it to be a fundamental circumstance, that water, when present in small 
amount in the materials of rocks which are subjected to heat and pres- 
sure, causes them to become plastic at a temperature far below the point 


LITHOLOGY. 171 


at which their materials are fusible. These views indicate that not only 
can eruptive rocks be derived from the unsolidified molten materials 
that are beneath the earth’s crust, but that matters once solidified may 
be refused, and that sedimentary deposits impregnated with water, 
though lying far removed from the seat of pure, igneous fusion, may be 
melted, and be erupted if circumstances favor. 

Dr. Hunt, who has advocated these views in this country, has been 
led by his studies to believe that the crust of the earth is so thick, and 
the agencies for liquefying once consolidated matter so efficient, that it is 
not to be expected that any erupted matter comes from such depths as 
that occupied by material which has never been consolidated, and that 
we are to look among the sediments for the equivalents of all erupted 
rocks, This view has been opposed by Prof. Dana, who points to the 
almost perfect uniformity in the composition of the Mesozoic traps, from 
Nova Scotia along the whole of the eastern border of our continent ; 
and which could not be expected in masses of fused sediments. It is not 
my place to discuss these theories. I only wish to make it plain, that if 
some clefts do descend to the matter which represents the original crust 
of the earth, it is admitted by all that sedimentary deposits may become 
fused or plastic; and in this circumstance we have an explanation of the 
fact that many of our eruptive rocks are very basic, many others are 
less so, and many more, which we are going on to consider, are highly 
acidic. Now, the Mesozoic diabase rocks which Prof. Dana shows to be 
so uniform in composition, form immense ridges, and occupy large fis- 
sures which were made by a wide-spread general subsidence, which 
would very likely produce profound fractures. In New Hampshire, no 
such uniformity of condition can be pointed to. Here and there, all over 
the state, are big and little cracks, often so small that they could scarce 
be expected to be very profound, and they are filled with basic rocks, the 
diversities of which indicate eruption at different times; and if, as will 
be shown, dykes of the same form and appearance are filled with acidic 
rocks, then diversity in the original composition of the basic eruptive 
rocks is certainly to be expected. 

= number of causes seem to have operated to produce structural 
differences. Rocks erupted in the later geological periods usually show 


a variety of effects which the laws:of cooling bodies explain. For exam- 


172 MINERALOGY AND LITHOLOGY. 


ple: the diabase of the Connecticut valley, when in large dykes, usually 
possesses a more coarsely crystalline structure than when in little ones, 
and the sides of the dykes which are in contact with the country rock 
are finer in texture than the centres. These differences in texture are 
produced by the influence of the surrounding rocks on the rapidity of 
cooling. Again: columnar structure, which, both in shape, size, and 
direction of the columns, is dependent upon certain well understood laws 
of cooling, is everywhere apparent. Our old trap rocks show but little 
of all this. The smallest dykes are often coarsest in texture, and hence 
we must conclude that either these rocks were erupted into cracks in 
hot rocks, that they did not reach the surface, and hence solidified under 
pressure, or that they have, with the strata in which they occur, been 
subjected to metamorphic action subsequent to their eruption. As any 
or all of these causes may have acted to produce structural differences, 
we can understand why our basic eruptive rocks are so diversified; why 
diabase, diorite, and gabbro were formed out of nearly the same ma- 
terial; and why coarse or fine, compact or porphyritic rocks were made 
in fissures of the same form. Moreover, it has already been pointed out 
that movements took place in the half-made rock, breaking up crystals 
already formed, and apparently introducing new conditions for finishing 
the solidification. In the gabbros, the well formed crystals of apatite, 
which after being perfectly formed were again partially dissolved, point 
also to variations in condition. The consideration of this element of 
variable conditions during the solidification of the rocks accounts for 
many differences in texture, and may especially be applied in the con- 
sideration of the porphyritic varieties. 

In reference to alteration and decay, it might appear that enough had 
been said, since the description of the rocks has consisted largely in 
details of the modes of decomposition. The natural conclusion of the 
process remains, however, to be considered. In New Hampshire one 
often finds dykes of compact white or light yellow material. This is 
usually one of two kinds of rock. Either it is a felsite, or it is a diabase, 
which by decomposition has lost all resemblance to its original self. 
Often this material can be found in connection with less modified por- 
tions, and the stages of decay can be noticed. I have sections cut from 
white decomposed diabase from Bemis brook and the Lincoln flume. 


LITHOLOGY. 173 


They show all the structures and the outlines of the original crystals tea 
characterize diabase, but every crystal is altered, and converted into 
an aggregate. A determination of the silica in the specimen from the 
Lincoln flume gave 40.04 per cent. Allowing for the carbonic acid and 
water present, this indicates no material increase in the amount of silica 
and the consequent presence of most of its original constituents, for the 
undecomposed rock at the Lincoln flume, the analysis of which is given 
on p. 153, is just like the one from Bemis brook. This decomposition pro- 
duct, however, contains a large proportion of carbonates of lime, iron, 
and magnesia. The size of the flume shows how much of this dyke has 
been removed; and when this decomposition product is broken down 
and carried away, these materials will be separated—the lime and mag- 
nesia will be carried to one place, the iron to another, and the siliceous 
residue to another; and this rock will be broken up into portions, which 
will be in part more basic, and in part less basic than the original rock.* 
The details of these processes of decomposition are as various as are 
the minerals and the circumstances that act upon them; but the gen- 
eral result is always the same, and hence this case may be taken as 
typical of the processes which have operated on the original basic crust 


of the earth to break it up and assort its materials into more and less 
basic portions. 


ACIDIC UNSTRATIFIED ROCKS. 


In approaching this great family of rocks, which with the crystalline 
schists forms our mountains and hills, some of the considerations 
drawn from the study of the basic eruptive rocks are of value. It was 
Stated that of such basic material the original crust of the earth was 
probably formed, and that by the ordinary processes of decay the bases 
of such rocks are in part removed, are accumulated in the sea and in 
beds of limestone and iron ore, while a siliceous residue is left behind, 
or is washed away and accumulated in sedimentary beds. Beneath these 
secondary products the original crust of the earth is now so deeply bur- 
ied that basic eruptive rocks are the only possible representatives of it. 
In some regions the limestone derivatives cover the whole surface; but 


ee ears 5 “ 
See, also, in this connection, the analysis of anorthite, on Page 91, and the remarks in connecti: ith 
ton with it, 


174 MINERALOGY AND LITHOLOGY. 


in New Hampshire the siliceous residues are the ones with which we 
chiefly have to deal. It has been stated that such sedimentary beds can 
become deeply buried, and that they may become plastic and enter into 
a condition that is termed igneo-aqueous fusion under the combined in- 
fluence of the weight of the sediments above them; the lateral pressures, 
the force of which is evinced in the elevation of our mountains; the inte- 
rior heat of the earth, and the water imprisoned in their mass, which in 
such circumstances becomes a most powerful reagent. This theory, 
which has been developed by the labors of several eminent geologists, 
has been strengthened by microscopic examinations, first and most prom- 
inent among which are those of Mr. Sorby, and it may be almost con- 
sidered to be demonstrated. The features in these rocks that render the 
theory so probable, will be pointed out in the proper places. 

Let us now suppose beds of great extent, such as may be derived from 
basic rocks by one or by repeated disintegrations, to be subjected to the 
influence of the agencies indicated. We may suppose, first, a wide varia- 
tion in the composition of the sedimentary beds, resulting from differ- 
ences in the agencies that had operated to decompose and re-deposit. 
From this cause, much diversity in the derivative rocks would appear. 
We may suppose a variability in the factors of heat and pressure, which 
would modify the completeness of the recrystallization or metamorphism ; 
hence some beds under powerful agencies would be entirely recrystal- 
lized, while others more gently acted on would be only partially altered, 
and would possess some of the original ingredients or features which 
would indicate their relationship to the stratified deposits. We may 
suppose, if no movements took place to disturb the beds while in this 
plastic condition, that, though recrystallized into massive rocks, they 
would maintain their position, and when solidified would still be con- 
formable with the surrounding strata. On the other hand, if great move- 
ments took place, such as must have accompanied the elevation of our 
White Mountains, fissures might be produced, into which the plastic 
rock might be forced, and the same identical rock might now present 
itself as an eruptive mass. Under other circumstances, the overlying 
strata might be crushed and mixed into the plastic mass; and many odd 
features in the arrangement and form of the masses might result from 
circumstances, All those who are familiar with our acidic rocks know 


LITHOLOGY. 175 


how commonly all these things are to be seen; and with this short expla- 
nation, intended to show unity where much diversity is apparent, we will 
proceed to the description of the more marked varieties of these rocks. 

Felsites, porphyritic felsites, granites, and sienites are the rocks that 
are considered in this general division. 


FELSITE. 


Felsite is a very fine-grained, compact rock, the composition of which 
is not at all evident to the eye on account of the minuteness of the crys- 
tals of its constituent minerals. In New Hampshire this rock is usually 
found in small dykes, and it usually has a white or gray color. It was 
long ago noticed that fragments were fusible before the blow-pipe, from 
which circumstance the nature of these dykes was suspected before it 
was known. In thin sections under the microscope it is seen to consist 
of an intimate mixture of quartz and orthoclase feldspar. It is the same 
substance as that which forms the ground mass of the porphyries, and 
hence its study forms a fitting introduction to that of those rocks. 

Felsitic substances are divided into two classes, according to certain 
microscopic properties which were first pointed out by Zirkel. The first 
class embraces those compact mixtures of quartz and feldspar, which, 
even under the microscope in thin sections, cannot be resolved into its 
constituent minerals, and would be called noncrystalline, except that be- 
tween crossed Nicols it does not become entirely dark, but shows faintly 
the optical properties of an aggregate. Glassy matters are, moreover, 
often present in such rocks. These rocks are called micro-felsitic. The 
rocks of the other class are to the eye homogeneous; but when thin sec- 
tions are magnified they are seen to consist of well individualized though 
minute grains of the constituent minerals. These rocks are called macro- 
felsitic; and to this class all our felsites belong, for, although some of 
them are extremely fine in texture, they can all be resolved into granular 
mixtures when sufficiently magnified. The rocks that occur about Mt. 
Washington may be described as typical. 

In going up the Mt. Washington river towards the gabbro rocks, sev- 
eral dykes of felsite are met with. They are white in color, and when 
freshly broken usually show some bright green spots, which at one time 
were cavities, but which are now filled by an aggregate of quartz and 


176 MINERALOGY AND LITHOLOGY. 


calcite, which is colored by a little of some chloritic substance. The 
mass of the rock is composed of very minute particles; and the quartz 
can be distinguished from the orthoclase by shutting off the light from 
beneath, when the feldspar, being partially decomposed, appears white 
and opaque, and the quartz, being still fresh, appears dark and clear. 
The feldspar forms the larger part of the rock. It is rather striking to 
notice that, just beside one of these felsite dykes, separated from it by 
merely a partition wall of the crystalline schists, there is a dyke of a 
black rock which a thin section shows to be a very fine-grained and con- 
siderably altered diabase. 

A specimen from a felsite dyke at Bemis brook is brownish yellow in 
color, and so very compact that it resembles jasper, but under the micro- 
scope, though it is seen to be very fine, its felsitic character is observed. 
Here and there, in the specimens of this felsite, a crystal of quartz or 
orthoclase is seen, and their sparing presence introduces one stage of the 
easy transition from felsite to porphyry. A large dyke in Bartlett is 
composed of a felsite which, when microscopically examined, is found to 
be porphyritic in its character. 

Some rocks in New. Hampshire have been called felsites, which differ 
essentially from them. In Albany there are some light red rocks, very 
fine in texture, and spotted with minute little black dots. When sections 
are cut from these rocks, they are found to consist of orthoclase crystals 
quite well formed, and of some size, and the black specks are found to 
be of hornblende. The rocks are only fine-grained sienites. 

Some very compact fine-grained rocks which resemble felsites are 
interstratified with the schists of the Connecticut valley. They are dis- 
tinguished from quartzite by the circumstance that they fuse, and they 
have therefore been called felsites. Under the microscope these rocks 
show the constituents of argillitic mica schists, to which they are related, 
and from which they differ in the less amount of the micaceous ingre- 
dient, which accounts for the more massive condition. 

The eruptive felsites often appear schistose; but this is a peculiarity 
which is often noticed, and is merely a secondary structure which has 
been induced in them. 


LITHOLOGY. 177 


Porpuyritic FersirE (PoRPHYRIES). 


The porphyritic felsites, or porphyries, constitute a large family of 
rocks in New Hampshire, and the great variety in their structure and 
mode of occurrence makes the study of them very interesting. At times, 
like the felsites, they fill small dykes, but often they form mountain 
masses. Before proceeding to their description, it will be well to call 
attention to studies that have been made elsewhere in our region. 

The porphyries are usually massive eruptive rocks. They form im- 
mense dykes; and in Silesia the columnar structure, and all other pecu- 
liarities of ordinary igneous rocks, are often seen. Dr. Hunt describes 
the porphyries of Canada as forming dykes, and in New Hampshire most 
of our porphyries are plainly enough eruptive. But in Massachusetts, in 
the neighborhood of Boston, there is a grand display of porphyries, fel- 
sites, etc; and Mr. T. T. Bouvé* has shown that every shade of varia- 
tion between most compact porphyry and conglomerate is to be there 
seen. This observation, which has been confirmed by other observers in 
other places, led Mr. Bouvé to assert the origin of porphyries from sedi- 
mentary deposits. Mr. J. C. Ward has also pointed out the passage by 
insensible gradations of certain fragmentary rocks into quartz porphyries 
in England.t If, now, the views in regard to the re-fusion of sediments, 
which have already been explained, are true, then the observations made 
by Mr. Bouvé are what would be expected, as a result either of a variation 
in the efficiency of the causes producing the fusion, or in the condition 
of the sediments submitted to their action. The same circumstance will 
explain the existence of many porphyries in New Hampshire, as, for ex- 
ample, a variety at Newcastle, and others elsewhere, which resemble 
sandstones while they have the features of porphyries, and which, even 
when microscopically examined, are hard to name. It is not our inten- 
tion to describe in detail these peculiar or doubtful varieties, but, recog- 
nizing their existence, and the light which they throw on the general 
subject, we propose to devote the space to the description of the inter- 
esting features presented by those immense masses of typical porphyry 
which are so important to our lithology. 


* Proceedings Boston Society of Natural History, 1862, p. 57; 1876, p. 217. 
t Quarterly Yournal Geol. Soc., No. 125, p. 25, 
VOL. IV. 23. 


178 MINERALOGY AND LITHOLOGY. 


Porphyritic felsites are sub-divided into three species. Quartz por- 
phyry consists of a felsitic mass of quartz and orthoclase, in which ma- 
croscopic crystals or grains of both these ingredients are developed. 
Orthoclase porphyry consists of the same ground mass in which ortho- 
clase alone is porphyritically developed. Quartz-free-orthoclase porphyry 
contains quartz neither porphyritically developed, nor in the ground mass. 
The last division, though represented, is of no practical importance in 
New Hampshire. 

Quartz Porphyry. Almost all the porphyries which occur in the state 
belong to this division. The ground mass is a felsite in which the pro- 
portion between the quartz and feldspar is variable, and in which mag- 
netite, augite, hornblende, biotite, chlorite, hematite, apatite, and some 
other minerals may be present as accessories. Of the porphyritic min- 
erals, the feldspar has usually a crystalline outline, and sometimes the 
quartz also. The greatest diversity in the appearance of the rocks pre- 
sents itself. Some are black, some are gray, and some are red, and they 
may have a ground mass of any one of these three colors, and porphyritic 
crystals developed in it of any other of the colors; and so the variations 
-become very numerous. This rock forms small dykes; and, on the other 
hand, immense mountains like Mt. Kearsarge are largely composed of it. 
Our porphyries are commonly massive rocks with no signs of structure, 
except in those cases where they possess a schistose nature that has 
been induced in them by external agencies. Their geological relation- 
ships, though sometimes evident, are more often obscure. 

In the north-east part of Waterville a beautiful d/ack porphyry is abun- 
dant, which, on account of the fine opalescence of its clear grains of feld- 
spar, has been supposed to be a dolerite or labradorite rock, but the thin 
sections show that only orthoclase feldspar is present. The ground mass 
is very feldspathic, and contains some augite, chlorite, magnetite, apatite, 
and scales of hematite. The feldspar is clear, but is filled with minute 
fissures and microlites, reflections from which cause the irridescence. 
The rock is a beautiful one, and it would be much admired if cut and 
polished. It was analyzed by Mr. Pease, in the Sheffield laboratory, with 
the following result : 


Silica, . 5 7 . 7 . . ‘ . : : 4 63.63 
Alumina, . . 3 ‘ 5 . 3 q ‘ 3 A ‘ 17.42 


LITHOLOGY. 179 


Iron sesquioxide, . ‘ F . 3 ‘ : ; . . 15 
Iron protoxide, eo <a So ae ep ap aw Ss 5.76 
Manganese protoxide, 022 
Lime, : : . : A , : ‘ 2.86 
Soda, a ‘ 3 bs g - P 3 , ; é ‘ 4.52 
Potash, . . - ‘ . ; ' 3 ; ‘s < 5-54 
Ignition, . 3 . Fi ‘ ‘ 5 . ‘ ‘ ‘ 15 

100.25 


This analysis confirms the examination of the section, showing that 
the rock is mainly feldspar; and, indeed, this analysis does not vary 
widely from that of orthoclase. Only here and there Smong the porphy- 
ritic crystals is there a black glassy grain of quartz, and it is as sparingly 
- present in the ground mass. <A porphyry of the same nature occurs at 
Lincoln. In thin sections of this rock the hornblende is conspicuous in 
crystals of some size. Augite was originally present, but is now mostly 
changed into chlorite and epidote. The rock also contains magnetite 
and pyrite. 

The black color of these quartz porphyries depends upon the circum- 
stance that the orthoclase is clear. When this character is absent, and 
the feldspar is no longer transparent, the rock, which is otherwise the 
same, is gray in color. Such a gray quartz porphyry from Mt. Lyon has 
some interesting microscopic features. Although many crystals of ortho- 
clase are porphyritically developed, they are not at all conspicuous in 
specimens. This is because they are so impure that they are scarcely 
individualized from the rest of the rock. Through the felsitic ground 
mass are distributed numerous rounded and angular grains of augite, bio- 
tite, chlorite, and magnetite; and through portions of the orthoclase 
crystals these grains are as thickly distributed as they are through the 
ground mass. The appearance of a section of this rock, as it looks in 
ordinary light, is represented in Fig. 2 on Pl. 10, If, now, polarized light 
be employed, the form of a large crystal of orthoclase is brought to view 
where nothing was visible before. The appearance of the same section 
in polarized light is represented in Fig. 3 on the same plate. This shows 
us that a pure, clear feldspar crystal began to grow in the rocks, but, for 
sone reason, a change took place in the conditions at a certain period of 
its growth, whereby in its further increase it was obliged to include par- 


180 MINERALOGY AND LITHOLOGY. 


ticles of the other minerals, which had formed or were forming in the 
rock. At first the particles were small, and were included in large num- 
bers, but afterwards they were larger and more sparingly distributed. 
That this line between the pure and impure parts of the crystal is indic- 
ative of some important change, is shown by the circumstance that this 
line also separates two parts of the crystal in which the optical constants 
are differently orientated. For this reason the outer and inner zones 
appear differently colored in polarized light; and the difference is more 
plainly marked by revolving the section till one part is dark, when it will 
be seen that the section must be turned a certain number of degrees 
from this point in order to induce the maximum of darkness in the other 
part. This indicates that the directions in which the planes of elasticity 
cut this section make an angle at the point which separates the pure and 
impure portions of the crystal. These directions are indicated in the 
figure; and in the case of the crystal represented, the difference between 
them is five degrees. All the porphyritic crystals of orthoclase in this 
rock possess these noticeable peculiarities, which are interesting as giv- 
ing evidence of the existence of stages of development. Indeed, the 
development of porphyries must depend more or less on the existence of 
stages, else the crystallization of large grains would have continued till 
the end. 

‘The presence of augite in large and small grains is noticeable in this 
porphyry. ‘It is not so very abundant as it is in the augitic porphyries 
about Leipzig, where it exists in such quantity as to relate the rocks 
which also contain plagioclase to diabase. But it is in this case, and in 
some others, a very characteristic feature of the rock. 

Sections of a gray—almost black—quartz porphyry from Groveton 
offer other microscopic peculiarities. The porphyritic crystals are mostly 
of orthoclase, some of which are subjected to exceptional methods of 
twinning. Compound crystals of orthoclase, when ingrown in the rocks, 
are usually Carlsbad twins, those of other kinds being very rare. In this 
Groveton porphyry most of the crystals are Carlsbad twins; but some of 
the crystals are also twinned according to a different system, the compo- 
sition plane being the clino-dome, and the twins consequently Baveno 
twins. The crystal which is most favorably cut to show this is repre- 
sented in Fig. 4 on Pl. 10. It lies on the edge of a section, and so half 


LITHOLOGY. 181 


of it has been broken away. It is, however, as fine a specimen as could 
be desired, to show a combination of two systerns of twinning. When 
revolved between crossed Nicol prisms, this section reaches its maximum 
of darkness when a side is parallel to the plane of vibration of the light. 
The ortho-diagonal therefore lies in the section; and if the section is 
prismatic, then one composition plane is parallel to the clino-diagonal, 
and the other composition plane is the clino-dome, and we have a double 
twinning, which is not uncommonly found in crystals which have devel- 
oped in cavities, but which is very rare in ingrown crystals. The con- 
trasts of color in the section are not very great, for, in a prismatic section 
cut approximately parallel to the ortho-diagonal, neither kind of revolu- 
tion throws the axes of elasticity far away from one another. Baveno 
twins have been found—first, by E. Weiss—in the sanidin of trachytes 
and modern eruptive rocks, but I am not aware of their having been ob- 
served in quartz porphyries, though they have been frequently observed, 
first by Rose, in granite.* 

This porphyry contains odd little concretionary masses of hornblende 
and chlorite, which fill spaces that were perhaps originally empty. The 
mineral grains on the outside are stained yellow by decomposition, and 
thus the bright green minerals within are surrounded by a yellow wreath. 
Crystals of orthoclase, which are pure within and impure without, are 
also found here. The porphyries of this place are stated by Prof. Hitch- 
cock to be plainly eruptive. 

A gray quartz porphyry from New Zealand contains so many large 
crystals of quartz and feldspar, that the porphyritic character is almost 
obliterated; and from this rock to granite is not a wide step. 

A gray quartz porphyry from Waterville possesses a very fine felsitic 
base; and the sections of many of the quartz grains are polygons, which 
indicate the presence of dehexahedrons of quartz that can often be ma- 
croscopically seen. As is usual in such porphyries, these crystals have 
rounded edges. 

This porphyry is a favorable one in which to observe the innumerable 
little cavities which are characteristically present in the quartz of all 
porphyries. When highly magnified, in these cavities a fluid and a bubble 
are almost always seen, and, moreover, a little colorless cube is often 


| & Rosenbusch Physiographie der massigin Gesteene, p. 12. 


182 MINERALOGY AND LITHOLOGY. 


found in the larger cavities. The cube is supposed to be of chloride of 
sodium, of which the fluid in the cavity is a super-saturated solution. 
These cavities are mostly entirely irregular in form, but sometimes one 
is found with hexagonal outlines, which correspond to those of the crys- 
tal which encloses it, and the cavity is really an inverted crystal. In Fig. 
6 on Pl. 6 some of the largest of these cavities, as they appear when very 
highly magnified, are represented. Such cavities are found in the quartz 
grains of nearly all the siliceous rocks; and hence what is here said will 
apply to most of those rocks which remain to be described. 

The bubbles which float in the fluids that these cavities contain can 
usually be made to disappear by heating the section to such a point that 
the expansion of the fluid is sufficient to fill the space. Some cavities 
contain a bubble, which disappears when the temperature of the section 
reaches about 30° C. In such cases the determination of the coéfficient 
of expansion, and the optical and other properties of the enclosed fluid, 
prove that it is liquid carbonic acid. Such cavities are very abundantly 
found in certain specimens of sienite from our state; but the bubble in 
the cavities of all the porphyries and granites that I have examined is 
little affected by heat, and would only disappear at a high temperature,— 
and the fluid is therefore water. 

Sorby * was the first to point out the geological significance to be at- 
tached to the presence of these cavities in the minerals of rocks, and he 
concluded that the mode of origin of a rock might be indicated from the 
circumstance whether it contained no cavities, or whether the cavities in 
it were empty, or filled with glassy material, or filled with fluid. The 
uniform presence of cavities filled with fluid in the quartz of granites he 
considered to be evidence confirming the views of Scrope and others, 
that water played an important part in the formation of these rocks. He 
moreover suggested that the relative volume of the fluid and the bubble 
might give some data for the calculation of the temperatures and pres- 
sures under which they were formed, since at a certain temperature the 
bubbles, which are spaces filled only with vapor of the fluid, disappear, 
and the fluid expands and fills the space as it must originally have done. 

But a determination of the temperature at which a cavity containing a 
vacuity in a fluid becomes full, gives only the temperature at which the 


* Phil, Mag. [4] xv, p. 152. Quarterly Fournal Geol. Soc., vol. xiv, p. 453. 


LITHOLOGY. 183 


fluid expands under the simple pressure of its own vapor to the volume 
of the cavity, while it is certain that the rock at the time it was made 
must have been under a heavy pressure. Hence the relative volume of 
bubble and cavity is dependent on two factors, one of which is the tem- 
perature, and the other is the pressure at the time the rock was solidified ; 
and if the coéfficient of expansion of the fluid is known, together with 
either one of these factors, the other can be calculated. Such calcula- 
tions were made by Mr. Sorby, and after him by Mr. J. Clifton Ward,* 
according to the formula deduced by Mr. Sorby. Such calculations are 
rendered of doubtful value by the large number of inconstants that are 
introduced. The accuracy of the measurements on such minute and 
irregular cavities is always doubtful, and neither one of the two factors 
is known. Still, the observations possess weight when the results are 
accepted as approximations, for, taking as one factor the lowest tempera- 
ture which would suffice to render these materials plastic with the aid of 
imprisoned water, the other factor is found to be very great; and hence 
these rocks must have been formed and solidified deep down in the 
bowels of the earth. This much can with certainty be assumed as the 
teaching of these minute cavities. Great variations in relative size of 
fluid and space, and in the expansibility of the fluid, caused by variable 
amounts of carbonic acid, which is either free or held in solution, are 
often observed in different cavities in the same crystal. This clearly 
indicates that changes of condition took place even in the growth of a 
single crystal. This variation in condition is also indicated by certain 
other microscopic properties of crystals in our porphyries, which I have 
already pointed out. 

The little cube which is so commonly seen in these cavities is proba- 
bly of chloride of sodium or potassium. On heightening the tempera- 
ture, this cube will dissolve. Its existence depends on the same causes 
as does that of the bubble. Water, when heated and under pressure, 
possesses a very great solvent power. Hence, when the temperature is 
diminished and the pressure removed, the fluid, which has dissolved alka- 
line salts from the feldspathic materials, becomes supersaturated. (See 
further remarks in reference to this subject under Granite.) 

The bubbles in the very-minute cavities, when highly magnified, are 


* Quarterly Four. Geol. Society, No, 124, p. 568. 


184 MINERALOGY AND LITHOLOGY. 


found to be in perpetual motion. They dance about, and move most 
irregularly from side to side of the cavity, as though acted upon by some 
very erratic power, These movements are referred to the same cause as 
the so-called Brownian movements of fine suspended matter, and have 
been explained in various ways. They are by some supposed to be 
caused by the constant molecular movements that are believed to take 
place in all fluids; by others, they are supposed to be caused by a 
vibration or jar, which, though inappreciable to our senses, thus evinces 
itself to be ever active; by others, they are referred to the action of light, 
or are to be explained in the same way as are the movements of Crooke’s 
radiometer. The motions referred to, which can be seen in any of our 
porphyries and granites, are certainly curious and interesting; but the 
phenomenon is a physical one, and has no geological significance. The 
lack of a satisfactory explanation will not therefore be felt. Zirkel re- 
marks, that whatever may be the cause, it is an interesting thought that 
these bubbles, in number approaching infinity, have been dancing about 
during all the ages since the rocks were made. Unless it shall be shown 
that they are influenced by light, and that their movements therefore 
date from the time that the sections were made, it certainly is a strange 
thought to think of so much motion ina lifeless mass. 

The region of Mt. Pequawket is a very interesting one in which to 
study the quartz porphyries, owing to their singular relationships to the 
surrounding rocks. At this point there are accumulations of clay slates; 
but at some places on the mountain they are all broken up, and again 
consolidated, so that they form an immense great breccia most striking 
in aspect. At some points which are characterized by this destruction 
of strata, the breccia is wholly of angular fragments of slate; at others, 
felsite and quartz porphyry form the cement which binds the fragments 
together; at other points, fragments of slate are sparingly distributed 
through the massive quartz porphyry. The region is, I think, considered 
a remarkable one by all those geologists who have visited it. It seems 
to be plainly indicated that here was the seat of some grand disturbance 
that resulted in the destruction of the strata of slate, and the eruption of 
quartz porphyries into the fissures made. Now, when the cavities in the 
minerals of plainly eruptive masses of porphyry or granite are examined, 
they show the same identical features as do others which appear to be 


LITHOLOGY. 185 


resting quietly in their original béds. If the eruptions reached the sur- 
face of the earth the pressures would be relieved; and as the cavities 
point as before to very heavy pressures, we are led to suppose that such 
disturbances are the result of movements which took place in the earth’s 
depths rather than upon its surface. The circumstance of the elevation 
of our mountains is sufficient to make plain the possibilities of such sub- 
terranean movements. This is an interesting spot, for such a mixture 
of stratified and unstratified material is not often seen. 

Quite a variety of quartz porphyries are found in this region. Some 
are colored red by the oxide of iron that seems to have separated from 
the decomposing minerals; in some, but few crystals are porphyritically 
developed, and some others are nearly granitic in their texture. On the 
lower half of the mountain a gray porphyry is prominent, which possesses 
a very fine, compact, rather earthy-appearing ground mass, in which not 
only feldspar crystals are developed, but also numerous dihexahedrons of 
quartz. Such porphyries as this were once called clay-stone porphyries, 
on account of the appearance of the ground mass. Another specimen 
of this rock has a basis still more earthy in appearance, which results 
from the abundant presence in it of chlorite, biotite, and iron oxide, 
which are only microscopically identified. Moat mountain, and some 
other mountains surrounding Pequawket, are largely composed of por- 
phyries. 

A porphyry just like this, save that in it very much larger crystals of 
orthoclase and quartz are developed, occurs in the Notch in the White 
Mountains. This porphyry is considered by Prof. Dana to form a bed, 
the position of which is conformable with the strata of slates and schists, 
and thus it presents a case of a porphyry which was not disturbed from 
the place where its metamorphism took place. 

A most diversified collection of porphyries can be obtained at Water- 
ville. They are of various colors, owing to combinations of differently 
colored ground mass and crystals, but the prevailing color is red. This 
color is seen in thin sections to be due to oxide of iron, which is abun- 
dant in the ground mass, and is often spread through the minute fissures 
in the orthoclase crystals. Sometimes a black grain of iron oxide in a 
strong light will appear blood-red, and it is thus recognized as hematite. 


These porphyries also vary widely in composition. In some, quartz is 
VOL. Iv. 24 


186 MINERALOGY AND LITHOLOGY. 


abundant, both in the ground mass and among the porphyritic crystals; 
in others, it is nearly absent from both. In one variety, feldspar crystals, 
with the basket-work structure characteristic of microcline, are found. 

In Albany there is a red quartz porphyry, in which some of the feld- 
spar crystals are penetrated through and through by apatite, the needles 
of which run into the ground mass in some places, but are not found in 
the quartz. 

On Twin mountain a very light gray quartz porphyry occurs, in thin 
sections of which the microscope reveals the presence of some light-col- 
ored garnets. These garnets are entirely irregular and formless, like the 
garnets found in granite. 

A porphyry breccia or porphyry conglomerate occurs at Waterville. 
This is a rock which is entirely composed of pebbles or angular frag- 
ments of red quartz porphyry, that have been cemented together into a 
very firm, hard rock. 

From these descriptions, I think it will be plain that the quartz por- 
phyries of New Hampshire form a group of rocks, which, though remark- 
ably uniform in general characteristics, are remarkably diversified in 
their details. This is a feature that is not at all peculiar to our state. 
Leonhardt says, in speaking of quartz porphyries,—“ Who that has trav- 
versed regions of porphyry has not noticed how often each hill and rock 
shows new peculiarities.’ This diversity, which is here so marked, and 
only the most general features of which have been pointed out, render 
these porphyries very interesting. One can read in the chapters written 
by Prof. Hitchcock how very widely distributed over our state are the 
porphyries, and how many mountains and cliffs are made of them. Many 
more might be described, but their differences are owing only to minor 
variations of the peculiarities already mentioned. 

Orthoclase Porphyry. This rock differs from quartz porphyry in that 
no quartz is macroscopically visible. Under the microscope, the ground 
mass is found to consist of the same mixture of minute grains of quartz 
and feldspar, with which a larger or smaller number of accessories are 
intermingled. Typical specimens of these rocks are found in Albany, 
and at Mt. Pleasant, which is just over the boundary of our state in 
Maine. In Albany, some of these rocks certainly occupy dykes; and 
Mt. Pleasant, which is largely composed of this variety of porphyry, is 


LITHOLOGY. 187 


regarded as an eruptive mass. The rocks are alike in both places, and 
one description will apply to both. They are either gray or very light 
red. The ground mass is usually very fine in its texture, but it is often 
porous and rough, and often very much resembles that of some modern 
trachytes. Were it not that the feldspar is opaque orthoclase instead 
of clear sanidin, one would immediately think of trachyte upon examin- 
ing these rocks. At some points on Mt. Pleasant the rocks are cracked 
up into angular blocks and fragments, as are many modern eruptive 
rocks; and in other places large crystalline grains of hornblende are 
prominent, and cause other kinds of trachytes to be recalled. Trachyte 
is a newly erupted rock, which, in addition to its glassy feldspar, con- 
tains noncrystalline substances,—nephelin, leucite, and the like; and 
though in special varieties any or all of its distinctive features or char- 
acteristic minerals may be wanting, the rocks as a class are very well 
distinguished, and no one would wish to confound such old rocks as 
these that we are considering with them. Still, I think these orthoclase 
porphyries from Albany and Mt. Pleasant are very interesting, since, by 
their very close macroscopic resemblance to certain trachytes, they show 
the close relationship which exists between these rocks and their younger 
kindred. Under the microscope no peculiarities of note are developed. 
Hornblende is found to be a common constituent; the feldspar is usually 
troubled by impurities and decomposition, but in some specimens it is 
quite fresh, though never glassy. On the summit of the mountain the 
ground mass is reduced to a minimum in quantity, and the rock ap- 
proaches sienite in appearance and composition. 

Quartz-Free Orthoclase Porphyry. This rock has the same structure 
as the other porphyries, but possesses quartz neither among the macro- 
scopic crystals nor in the ground mass. A rock of limited distribution 
anywhere, it is of no practical importance in New Hampshire, for it oc- 
curs as a mere exceptional variety in one or two places among the quartz 
porphyries. For example: a specimen of red porphyry from Waterville 
and another from Albany are remarkable because no quartz can be de- 
tected in them, while at the same time a triclinic feldspar, conspicuous 
in polarized light by its bands of color, appears as an ingredient, and by 
its presence suggests the more basic nature of the rock. 

In these varieties of porphyry in which large crystals of quartz do not 


188 MINERALOGY AND LITHOLOGY. 


appear, no cavities containing fluid are found. It is considered that 
probably water played its important part in the crystallization of these 
rocks; but feldspar, even if it does imprison some water, does not often 
hold it, but allows it to escape through minute cleavages, or absorbs it 
into its decomposition products, while quartz holds what it contains 
through all time, and hence, even in the oldest rocks, the quartz is full of 
fluidal enclosures. 

In dismissing this subject it will be well to mention two or three less 
typical varieties which indicate how narrow are the spaces which divide 
our great families of rocks. On Little Deer brook, in Albany, a quartz 
porphyry occurs, in the ground mass of which quite large grains of mus- 
covite mica are developed. A specimen from Kirby, Vt., possesses but 
little ground mass, and what there is is coarse, and in it both muscovite 
and biotite are seen. A specimen from Newcastle is:also largely crys- 
talline, but hornblende, and not mica, is conspicuous in the thin sections. 
These circumstances indicate that between typical porphyries and typical 
granites, many intermediate varieties occur, which, from the nature of 
the case, are to be expected. 


Granitic Rocks. 


Under this head are included those massive acidic rocks which are 
entirely granular in their structure. They possess at times a pseudo-por- 
phyritic structure, induced by the more prominent development of ortho- 
clase crystals ; but to the unaided eye, all parts of the rock are plainly 
granular. They have certain features in common, which may be men- 
tioned before describing individual species. They all possess indications 
of having once been in a molten or plastic condition; and, like the rocks 
last described, the evidence they offer is not that of an igneous fusion, 
but rather of a plasticity induced at a low temperature, and under press- 
ure, by the aid of water. Therefore it may be again remarked in this 
connection, that we may expect to find these rocks in the places where 
they originally existed as stratified sediments, in dykes intruding them- 
selves through other strata, and in the most varied, apparently systemless 
forms which might happen to be imposed upon them by the circum- 
stances that befell them while yet plastic; and all these differences, 


LITHOLOGY. 189 


though of great geological interest, may be wholly unrecognizable in the 
lithological study of specimens. All the features referred to are very 
often found in our state. There are beds of granite which are conforma- 
ble with associated stratified rocks, There are granites filling well 
defined dykes. There are granites which, so far as can be seen, are 
entirely void of structural relationships. There are granites which are 
mixed with other rocks, or which hold huge fragments of other rocks 
enclosed in their masses. All these features are often repeated; and 
when one wonders at their diversity, he has but to think of those tre- 
mendous movements which have taken place in the crust of the earth, 
and that any plastic materials which were influenced by these move- 
ments would take the forms and relationships to other rocks which local 
circumstances determined. 

Dr. Hunt, who has made a careful study of the granites of this part of 
the world, has divided them into three classes. The first class embraces 
the granites which are in place among the strata, and which he calls 
indigenous granites; the second class embraces the intrusive granites, 
which are called exotic; and the third embraces granitic veinstones, 
which are called endogenous. The members of the last class are dis- 
tinct in origin, and hence in lithological characters. The rocks of the 
exotic class, however, show just the same evidences of having solidified 
under pressure as do those in place. It is not claimed that they result 
from eruptions that reached the free surface where the pressure would 
be removed, but they entered cracks in overlying strata, and solidified 
like the others in the depths of the earth. Hence the members of the 
first two classes cannot be expected to be lithologically distinct. 

The minerals of which the rocks of this group are composed are 
quartz, orthoclase, and plagioclase, of which, in variable proportion, the 
bulk of the rock is always composed; and muscovite, biotite, hornblende, 
augite, chlorite, tourmaline, graphite, and hematite, one or more of which 
may be present as characterizing accessories ; and beside these, a variety 
of minerals, such as apatite, rutile, zircon, microcline, &c., are micro- 
scopically detected, and which are of interest, though they form no pro- 
portion of the bulk of the rock. 

Authorities differ in sub-dividing this group. Some, considering quartz 
and feldspar as the essential constituents, sub-divide the rocks into gran- 


190 MINERALOGY AND LITHOLOGY. 


ites which contain both feldspar and quartz, and sienites which contain 
only feldspar. The granites are then further sub-divided, according as 
to what mineral is present as the characteristic accessory, and the sien- 
ites are likewise sub-divided. Other authorities, considering the distinc- 
tion between hornblende and mica as fundamental, divide them into 
granites which are micaceous, and sienites which are hornblendic. In 
this work the first method of sub-division is adopted, and the following 
kinds of granitic rocks have been identified in the state: 


Granite. 


Muscovite granite. 

Muscovite biotite granite. 

Biotite granite. 

Mica hornblende granite. 

Hornblende granite. 

Chlorite granite, or protogene. 
Granitell, or granite with no accessory. 
Granite of veins. 


Sienite. 


Augite sienite. 
Hornblende sienite. 


GRANITE. 


Although our granites can be sub-divided according as they contain 
muscovite, biotite, hornblende, or chlorite as the characteristic accessory, 
yet the dividing points between these sub-species can only be arbitrarily 
assumed, since most of our granites contain two of these minerals, many 
contain three, and some contain all four. It is therefore the predomi- 
nance of one or the other that forms the species; and the intimate 
blending of these species causes them, together with the granitell, to 
form one well defined rock group, all the members of which are in com- 
mon usage called granite. As the quartz and feldspar are light-colored 
minerals, the accessories are rendered very prominent, and determine 
to a great degree the color of the rock. The granites that contain no 
accessory or muscovite are white; biotite and hornblende granites are 


‘LITHOLOGY. 191 


spotted black; and chlorite granites are spotted green. Not only is it 
difficult to generalize on the distribution of these granites, but more than 
one of them may occur associated together. 

Some features which the granites possess in common may be men- 
tioned before describing the peculiarities of our individual species, be- 
cause they indicate the mode of formation of these important rocks. 
The relationship of the component minerals to each other as regards the 
order of their crystallization is the first and most evident feature to con- 
sider. When rocks which without doubt have solidified from a state of 
igneous fusion are studied, it is found that the least fusible constituents 
were the first to crystallize. They appear in well defined forms or per- 
fect crystals, and the least fusible constituents fill the interspaces. But 
this is all changed when granitic rocks are observed. Quartz is com- 
monly called infusiblé, and feldspar is easily fused, yet the feldspar was 
the first mineral to crystallize, and has obtained its well defined form 
apparently uninfluenced by the other minerals, while the infusible quartz 
fills up the interspaces, and was the last to solidify. Although micro- 
scopic sections are not at all necessary to observe this point, yet in 
them this relationship, which is so easily recognized macroscopically, 
is found to extend to the minutest structures. This is illustrated in 
Fig. 5 on Pl. 10, which is drawn from a section of a granite from Cole- 
brook. The well defined orthoclase crystals are there shown, and the 
quartz fills the residuum of space. This fact was observed as long ago as 
1822, when Breislak, in his treatise on the structure of the globe, argued 
against the igneous nature of granites on the basis of exactly these ob- 
servations, yet it is only recently that these arguments have been re- 
garded as conclusive. But observations in the field prove plainly that 
some at least of the granites have been in a fused or plastic condition. 
These circumstances must point, therefore, to a plasticity which was 
induced in some other way than by pure igneous fusion. The relation- 
ship between the crystallization of minerals and their fusibility extends 
still further. Granite often contains a variety of minerals, such as tour- 
maline, garnet, zircon, iolite, fluor spar, etc.; and although all degrees of 
fusibility are represented, no generalizations can be made upon the order 
of their crystallization. Such observations as these were the starting- 
points from which Scrope, Scheerer, and others, supported by Sorby and 


192 MINERALOGY AND LITHOLOGY. 


the microscopic geologists of later times, have developed the theory of 
igneo-aqueous fusion to account for the formation of granite, a theory 
about which so many observations have been accumulated that its truth 
is nearly demonstrated. 

In granites, the feldspar is almost always troubled by the inclusion of 
impurities, by rifts and decomposition products, which in thin sections 
throw it into striking contrast with the clear quartz, which, though free 
from the cleavage and enclosures of the feldspar, always contains the 
cavities which are filled with water, and a bubble, and often crystals of 
salt.* The quartz, as the last mineral to crystallize, of necessity took in 
the fluid residue, and, being difficult to decompose, has held it. Sorby 
has been led by his observations on these cavities in granites to believe 
that the temperature at which the quartz finally solidified is that which 
marks the critical point when compressed steam passes to water, which 
is at about the melting point of zinc (412 C). This is based on the 
observation that the few cavities that exist in the feldspar of certain 
granites contain but little water and no separated salts. This indicates 
that the feldspar crystallized at a temperature above the critical point 
of water, which in a gaseous state cannot dissolve salts, and hence the 
cavities are nearly empty and destitute of crystals. The abundant pres: 
ence of salts suspended in the water contained in cavities in the guartz 
shows that the quartz, on the contrary, was still plastic at the tempera- 
ture below the critical point of water, which as a fluid, when highly 
heated, is a most powerful solvent, and hence would dissolve soluble 
constituents from the other minerals, and on cooling it would be a super- 
saturated solution. This temperature agrees very closely with that de- 
duced from his calculations made upon the measurements of the relative 
size of bubble and cavity. It is interesting, however, in this connection, 
to note that the temperature of 412 C. is the point at which substances 
possess a dull red heat; and Scheerert deduced this same result from his 
studies on the pyrognomic minerals held in granite. He considered that 
the existence of certain minerals, such as gadolinite, allanite, &c., which 
at a temperature not above a brown red suddenly disengage heat, glow 


* See p. 183. 
} Mineralogical Magazine, Nov., 1876. 
{ Bul. de la Société Géologigue de France, second series, 1846, vol. 4, p. 487. 


LITHOLOGY. 193 


with brilliancy, and are then found to have suffered marked physical 
changes in color, specific gravity, deportment with acids, &c., to be proof 
that the granite must have formed at a temperature not above that indi- 
cated by a dull red. 

Now, it has already been explained that the size of the bubble in a 
fluidal cavity is dependént on two factors, temperature and pressure, 
either of which being known the other can be calculated. Assuming 
the stated temperature as being correct, Mr. Sorby has calculated the 
pressure in a variety of cases, and finds it, though variable, to be always 
enormous. Mr. Ward* followed with more extensive calculations, using 
the same formule. Comparing the results with those obtained in the 
field, it was usually found that the pressures deduced from calculation 
are much larger than those which would result from the pressure of the 
superincumbent strata that can be proved to have rested upon the rocks 
investigated. If, for example, the calculations indicate a pressure equal 
to 50,000 feet of rock, but 30,000 can be found, etc. This indicates that 
granites are rocks which were formed deep down in the earth, and crys- 
tallized from a plastic condition, under pressure, which resulted in part 
from the weight of superincumbent strata, and in part from the lateral 
pressure which elevated the mountains. Although accuracy can scarcely 
be claimed for such calculations, their general agreement, when regarded 
as approximations, renders them valuable. Much more, which is very 
interesting, has been done to substantiate the accepted theory ; and espe- 
cially in this connection may be mentioned the experimental researches 
of Daubree, who has reproduced some of the circumstances in sealed 
tubes, and crystallized the minerals. Enough has been said, however, 
to define the method by which the members of our most important 
group of rocks were formed, and to explain the variety of circumstances 
in their mode of occurrence which is met with. 

Muscovite Granite. This is an uncommon rock, and the one specimen 
that I have to examine comes from Newcastle, where it occurs sparingly. 
It is therefore a rock of little importance to us. It would seem as if the 
entire removal of iron from sediments was usually accompanied by the 
removal of so many other constituents as rarely to leave the material for 


* Quart. Four. Geol. Soc., Nos. 124 and 125. 


VOL. Iv. 25 


194 MINERALOGY AND LITHOLOGY. 


granites ;—therefore the micaceous rocks in our state which contain only 
muscovite are the more quartzose varieties of schist. 

Muscovite Biotite Granite. The larger part of those fine-grained com- 
pact granites that are so extensively quarried in our state is of this 
kind. The Concord granite is a beautiful stone, which is fine in texture 
and light in color. Larger twin orthoclase crystals are sparingly distrib- 
uted through it. Thin sections show some interesting features. Finely 
banded oligoclase crystals are common; and through some of the ortho- 
clase crystals laminze of a triclinic feldspar are arranged in two direc- 
tions at right angles to one another. This kind of interlamination is 
frequently observed in free-grown crystals, in which case the laminze are 
usually of albite; and it is very likely that they are of albite in this case, 
although proof of it is scarcely possible. A crystal of this kind, as seen 
in a section of Concord granite, is represented in Fig.6 on Pl. 5. The 
quartz is very clear, and the cavities in it are very small; but every grain 
is penetrated through and through with the most minute dark needles of 
rutile, which look like the finest hairs. The larger grains of mica are not 
crystalline in outline; but some very perfect microscopic crystals are scat- 
tered through the quartz. Occasionally a hexagonal needle of apatite is 
found, which, though small, is recognizable. A bit of chlorite is rarely 
seen. The orthoclase is tolerably clear; and the structure and composi- 
tion of the whole indicate a very durable rock. 

This Concord granite is typical of a group of granites which are re- 
garded by Prof. Hitchcock as belonging to the stratified series which 
forms the Montalban system. A number of thin sections have been 
made from members of this group (called Concord granites), and the 
variations in their microscopic characters are of an unessential nat- 
ure. In sections of the Fitzwilliam granite, crystals of zircon are notice- 
able, which, though very minute, are quite perfect. Some of them have 
been represented in Fig. 1 on Pl. 5. The crystals of rutile characterize 
the quartz of this as of all the Concord granites. The crysfals of inter- 
laminated feldspar are not found, but others, with the very intricate bas- 
ket-work structure that characterizes microcline, are seen. In another 
specimen, which is cut from what is called the best quality of the Fitz- 
william granite, a pretty microscopic structure is developed in some of 
the grains of feldspar, which is caused by the arrangement through them 


LITHOLOGY. 195 


of laminz of white mica, in two determinate directions. The same lam- 
inze appear in the quartz, but there they lie scattered at hap-hazard 
through its mass. This granite contains a large proportion of quartz. 
The Marlborough granite is in all microscopic characteristics the same, 
but it is gneissoid in structure; and, indeed, it is said that all of these 
Concord granites show indications of a gneissoid structure in the 
quarries, although in specimens no structure whatever is to be seen. 
The Troy granite is like the Concord, but is lighter in color, and its thin 
sections are remarkable for the large proportion of microcline they con- 
tain. The structure of this microcline is very beautiful, and often its 
laminee are of extreme fineness. Fig. 6 on Pl. 10 represents a section of 
the Troy granite. A grain of microcline is in the middle. The quartz 
shows its characteristic enclosures, consisting of cavities, needles of 
rutile, and mica. The light muscovite is seen on the right, the dark bio- 
tite on the left, and the orthoclase above. The Roxbury granite is char- 
acterized like the Troy by much microcline. The multitude of minute 
though very perfect muscovite crystals that lie scattered through some 
of the grains of quartz is noticeable. Fig. 2 on Pl. 5 is drawn from a 
section of this granite (see p. 86). Other specimens representing the 
formation of so-called Concord granites offer but little in addition. A 
specimen from Manchester, and another from Plymouth, are darker, be- 
cause the muscovite nearly fails; one from Hooksett is lighter, because 
the biotite nearly fails. The Sunapee granites are in part light and in 
part dark. The beautiful Haverhill granite is very rich in quartz. A 
specimen from Effingham is very coarse and pseudo-porphyritic; but, 
with such minor variations, this granite, from all its localities, possesses 
the same distinctive microscopic structure and peculiarities. 

Biotite Granite. The granites in which biotite alone appears as the 
characteristic accessory are very numerous. Prominent among these are 
the Conway granites, which are characterized by their ready disintegra- 
tion. Any one who visits the region of Conway cannot but be struck 
with the immense amount of granitic sand and gravel which is there 
accumulated. Yards and streets are covered with the small fragments 
of disintegrated granites ; and not being rolled or water-worn, these bits 
preserve their angular forms. All around the country in the region of 
Conway numerous large blocks of granite are lying about, which one can 


196 MINERALOGY AND LITHOLOGY. . 


kick into a heap of sand. The rocks appear to have what was called by 
Dolomieu, “La maladie du Granite,’ which he supposed to be due to 
the action of carbonic acid issuing from a subterranean source, but the 
true nature of the disease is’ discovered by microscopic examination. 
When we look at thin sections of the granites that withstand the influ- 
ences of time, or only wear upon the surfaces, we find that their grains 
of feldspar are clear, and contain but few impurities or cavities. But the 
feldspar of these Conway granites is filled with innumerable pores, and 
with dirty matters that make it milky and opaque. Fig. 1 on Pl. xi 
represents a section of one of the Conway granites. The grain of biotite, 
bent and twisted, as if acted upon by some force after it had formed, is 
noticeable: it includes between its laminze quartz, pyrites, and magnet- 
ite. Such grains of biotite are not uncommon. The impurity and 
opacity of the feldspar is the chief feature, but to resolve the muddy 
mass, a much higher magnifying power is required. Such porous impure 
feldspars cannot withstand the influences of the weather. The water 
enters the cleavages and pores, and soon it needs but a blow to break it 
down. If one notice the pile of gravel that results from destruction of 
a block of this granite, it will be seen that the cleavage surfaces of all 
the feldspar crystals are covered with rust, which was carried into the 
cracks from the decaying mica, but the quartz grains will be found 
intact. Here is seen, in its simplest form, the first step of the deriva- 
tion of soils from the disintegration of rocks. Further changes take 
place when the feldspar is entirely decomposed and converted into kaolin, 
for then it may be washed away and deposited in clay beds, or disposed 
of in other ways as circumstances determine. In regions below that of 
glacial action immense masses of such material occupy the place of the 
original granitic rocks, and the subject has been‘studied in tropical re- 
gions by Darwin, Agassiz, and others. In our parts, all products of 
decomposition that were loosened before the glacial epoch have been 
carried away, and only the granites that are peculiarly subject to decay 
are deeply disintegrated in their original beds. 

The Antrim granite is a pseudo-porphyritic granite, that is, it is a rock 
in which large crystals of orthoclase are developed, not in a compact 
ground mass, but in an already coarsely crystalline mass. Many of our 
granites have this structure. Garnets are numerous in the Antrim gran- 


LITHOLOGY. 197 


ite. It is instructive to note how generally in our granites the garnets 
are entirely without outer form, while in the vein granites and crystalline 
schists they are so often quite perfect. A section of the Antrim gran- 
ite, in which a garnet is included, is represented in Fig. 2 on Pl. xi. The 
_ form that the garnet takes seems to be entirely dependent on its surround- 
ings, and it encloses in its mass portions of both the biotite and quartz. 
The Antrim granite contains apatite in little hexagonal prisms, and also 
in numerous radiating groups of minute needles. Hornblende enters spar- 
ingly into the composition of the rock ; also, oligoclase, pyrite, and magne- 
tite. Excessively fine and very long needles of rutile pierce the quartz. 
But if, as has been shown, many of our granites retain traces of a 
stratified structure, which cause them to be referred to old sedimentary 
formations, in other places granite possesses the character of an erup- 
tive rock. The most remarkable occurrences of this nature are at 
Franconia and the Notch. At these points a light-colored biotite gran- 
ite occurs, and embedded in it are very numerous angular fragments of 
gneiss. Some of these fragments are small, some are very large; and 
thus there is formed an immense breccia, which cannot be represented 
in the cabinet on account of its great proportions.* This granite is 
called by Prof. Hitchcock the dveccta grantte. In the Notch, the point. 
where this granite occurs is regarded by Prof. Dana as the axis of an 
anticlinal, as proven by the arrangement of strata, and the large number. 
of granitic veins in the surrounding rocks. If, now, as suggested, gran- 
ite was once plastic, under the combined influence of heat and vertical 
and lateral pressure, it is easy to suppose that, when an upheaval took 
place, and the rocks were rent into a mass of broken fragments of the 
overlying strata, the underlying plastic mass might be forced, and being 
thus partially relieved from pressure, would solidify about the frag- 
ments, and form a breccia such as there exists, These breccias are 
certainly grand and interesting lithological examples, 
Many of the biotite granites are red, on account of the color which. 
oxide of iron imparts to the feldspar. One variety of the Conway gran- 
~ escounts ovr « €FCY peak in Stratford, are deep red; one from 
from Stark, possess a beautiful and delicate. 
ax Cause. Some. specimens of biotite granite are 


pete aie, een BSE 


* For figures, etc., see vol. ii, p, 169, of this report. 


198 MINERALOGY AND LITHOLOGY. 


nearly black, on account of the preponderance of biotite. Such is a very 
handsome granite from Newcastle. 

A specimen of biotite granite from Franconia is somewhat remarkable, 
on account of the presence of fluor spar as one of its microscopic ingre- 
dients. A little hornblende is also present, which has a peculiar dichro- 
ism, being deep brown in one direction and dark blue in the other. 

A specimen from Whitefield is remarkable for its large amount of mag- 
netite. In it quartz largely predominates, and the mica is mostly in very 
minute grains. A specimen from Ossipee is remarkable for its large 
content of plagioclase and microcline, and which together outweigh in 
amount the orthoclase. It contains extremely long needles of rutile. 

Mica Hornblende Granites. Granites are numerous in which both mica 
and hornblende can be seen with the unaided eye, but the microscope 
enlarges this class widely. In some of the mica granites a bit of horn- 
blende is often found; but in those now to be mentioned the hornblende 
plays an important part. 

As typical of one class of these granites, a light-colored specimen from 
Colebrook may be described. In this granite, biotite and hornblende are 
most intimately mixed together. Sometimes one of the black spots that 
dot this granite will be seen under the microscope to be all of one or all 
of the other of these minerals, but more often of both. The two minerals 
are both very strongly dichroic, both being deep brown when the light 
passes in one direction, and deep yellow when it passes at right angles 
thereto. This rock contains considerable oligoclase. Apatite crystals 
of perfect form are quite common, and some epidote is present as a de- 
composition product. 

A number of handsome dark-colored granites, which are characterized 
by a kind of an olive-green color, are of this class. A specimen from 
Lightning mountain may be taken as typical, The rock is almost wholly 
composed of quartz and orthoclase, but the orthoclase is not of the white 
or colored opaque kind that is most common; it is the transparent 
variety that is called adularia. It has a very waxy lustre and a greenish 
tint, and imparts these characters to the rock. Under the microscope it 
is found to be much clearer, and more free from inclusions than our com- 
mon feldspar. The quartz is of a dark, smoky color, and only on close 
examination are grains of hornblende distinguished from it; but in thin 


LITHOLOGY. 199 


sections plenty of both hornblende and biotite are found between the 
larger grains of quartz and feldspar. The hornblende is very deeply 
colored, and the light that passes in one direction is green. Consider- 
able magnetite and apatite and some oligoclase are present. A specimen 
from Iron mountain in Bartlett only differs in that the biotite and horn- 
blende, being more abundant, are more conspicuous in the hand speci- 
mens; and the orthoclase possesses at times a pretty and striking opal- 
escence, which is due to minute cleavages, as has already been explained. 
Very wide variations take place in the proportion in which the acces- 
sory ingredients are present, while the rock maintains unmodified its 
typical color and appearance. For example: biotite and hornblende 
are sometimes very conspicuous; but, again, as on Mt. Lafayette, these 
ingredients are very sparingly present, and macroscopically are scarcely 
recognizable, and the rock differs, therefore, but little from granitell. At 
Ossipee and at Frankenstein cliff the biotite is almost absent, while horn- 
blende is prominent, and the rock becomes a hornblende granite. At 
Stark the quartz and biotite are both withdrawn, and the rock becomes 
sienite. These rocks, at all the localities mentioned, are regarded by 
Prof. Hitchcock as eruptive. From their peculiar appearance they have 
attracted considerable attention, and some doubts have been entertained 
in regard to their classification; but with the exception of the Stark 
variety they are simply granites, with unessential variations in the rela- 
tive amqunts of the accessories, and their only peculiarity is the con- 
stancy in the character of the feldspar, which in all is the preponderating 
mineral. The clearness and purity of this feldspar, which in thin sec- 
tions is in marked contrast to that of the disintegrating granites, such as 
as those in Conway, indicate that these granites will remain firm and 
solid after time has worn away the Conway rocks. 

Some granites occur in Albany, which have certain characteristics 
which extend over a class to which the name Albany granite has been 
given. They are very hard and durable rocks, and possess some of the 
peculiarities of the granites last described. The characteristic features 
of these granites are, that they are composed of a mass of minute crys- 
tals in which larger crystals of orthoclase are often porphyritically devel- 
oped; and the black constituents, like little specks, are so scattered 
through the ground mass as to give rise to an appearance which has 


200 MINERALOGY AND’ LITHOLOGY. 


been compared to pepper and salt. These little black specks are found, 
on microscopic examination, to be in part biotite and in part hornblende, 
though, as in the last class, these ingredients are variable, both in their 
amount as relates to one another, and to the mass of the rock. At some 
points, as, for example, at Jackson falls, these rocks are characterized by 
their frequent inclusion of fragments of other rocks. This circumstance, 
among others, has caused them to be all considered as eruptive. Though 
this may not be improbable, this circumstance of itself is not sufficient to 
prove the eruptive origin of a granite, for it has been more than once 
pointed out that some granites are partially fragmental in their nature. 
The little grains of hornblende in thin sections often appear quite well 
crystallized. Plagioclase, and little crystals of apatite, are conspicuous. 

A very peculiar granite has been cut by the railroad at Bemis station. 
It is fine in its texture, and light gray in color. In thin sections its 
accessories are found to be white hornblende and muscovite. Besides 
these, sphene, in irregular grains, is abundantly scattered through it. 
Plagioclase, pyrite, and pyrrhotite are also ingredients. This rock is, 
so far as I am acquainted, an isolated occurrence. 

A granitic rock from Portsmouth contains green dichroic hornblende 
and muscovite, but so much plagioclase that it brings to mind the quartz 
diorites that are found in the region. 

Hlornblende Granites. The granites in which hornblende alone ap- 
pears as the characteristic accessory are fewer in number ¢han the 
last. Prominent among these is the Chocorua granite. In thin sec- 
tions, the hornblende of this granite is very dark in color, and strongly 
dichroic. A little scale of mica is occasionally found. As accessory 
constituents, titanic iron, hematite in blood red, translucent grains, fluor 
spar in grains with an attempt at crystallization, and epidote in grains 
with a most delicate feathery fringe, are present. The orthoclase is 
quite pure, but is made up of those irregular laminze which are repre- 
sented in Fig. 1 on Pl. 8, and which are only seen in polarized light. 
They result from the circumstance that in the two interlaminated parts 
of the crystal the axes of elasticity are somewhat different in their ar- 
rangement, and hence the interference colors obtained in any given posi- 
tion between the Nicol prisms are different. This granite has a greenish 
tint, which is imparted to it by epidote. 


LITHOLOGY. 201 


Another of these hornblendic rocks from the top of Mt. Carrigain is 
very peculiar in its microscopic structure. Macroscopically, this rock is 
fine in texture and dark in color, and its individual constituents cannot 
be determined. Under the microscope its thin sections show that the 
dark constituent is greenish hornblende, though it is partially altered 
into epidote and chlorite; but the circumstance of note is, that many of 
the minute grains of feldspar are inlaid with quartz, in the manner pecu- 
liar to graphic granite. The rock is hence a kind of microscopic peg- 
matite. The figures that are formed are often of rare perfection. A 
grain of the orthoclase, much magnified, is represented in Fig. 3 on 
Pl. xi. Mr. Michel Levy* found this character in quite a number of 
French granites (granitoid porphyries, etc.) and considered this charac- 
ter, among others, in attempting to find constant relationships between 
microscopic characters and geological age. The pegmatitic character of 
a rock he regards as evidence of the simultaneous crystallization of 
quartz and feldspar, and this character separates such rocks from those 
in which one clearly solidified before the other, and indicates in a degree 
an approach toward those characters of crystallization that are peculiar 
to newly erupted rocks. Our rocks have not been sufficiently studied to 
enable us to say anything about such a matter; but though such investi- 
gations are very interesting, the results are, as yet, at least hypothetical. 

A very fine-grained hornblende granite is found in a well defined dyke, 
which cuts vertically through the coarse-grained gneissoid rocks on the 
Swift river in Albany. 

A light-colored hornblendic granite comes from Stark; a red variety 
comes from Jackson ;—but an enumeration of any peculiarities that I 
have observed in these or other rocks of this class would be a mere 
repetition of what has gone before. 

Protogene. This is a name given to those granites which, as an acces- 
sory, contain chlorite, talc, rotten mica, or other decomposition products, 
and which are made characteristically green by the presence of one of 
these ingredients. In the neighborhood of Littleton such rocks reach a 
considerable development. They are mainly composed of quartz, ortho- 
clase, and chlorite, but in thin sections some hornblende is also seen. 
The little plagioclase that the rock contains is much altered. This 


* Bulletin de la Soc. Geol. de France, 1875, p. 199. 
VOL. Iv. 26 


202 MINERALOGY AND LITHOLOGY. 


same rock is also found at Hanover, and it is a characteristic rock among 
the valley formations, varying in color from a light to a dirty dark green. 
At Lancaster a bright green variety is found, which contains many very 
large crystals of orthoclase porphyritically developed, and which are 
usually twins. It contains crystals of pyrites, which harm the utility of 
an otherwise beautiful stone. This rock at Lancaster becomes gneis- 
soid in structure at some points, and it is everywhere plainly a member 
of the formation in which it occurs. At Lebanon a beautiful, green- 
spotted variety of this rock is quarried; but in the centre of each green 
spot scales of biotite are seen, which indicate that the biotite has fur- 
nished the decomposition product. In thin sections of this granite from 
Walling’s quarry the green decomposition product is seen to be epidote, 
which in minute rounded grains is scattered most plentifully through 
the rocks in the neighborhood of the biotite. A chloritic granite also 
comes from Groveton. 

Granitell, Granitell is the rock in which all the chief accessories of 
granite are characteristically absent. It therefore lacks the spotted char- 
acter of ordinary granite. It is a rock of limited distribution, and in 
New Hampshire cannot be called typical of any great formation, as are 
some of the other varieties of granite. 

On Little Ascutney mountain there are granitell rocks, which, on ac- 
count of decomposition, are yellow in color, and which contain little else 
besides quartz and orthoclase. For microscopic study they furnish beau- 
tiful specimens, since the quartz is filled with cavities of unusual size; 
and in the cavities cubes of salt, also, of unusual size are found. It is 
interesting to note that some cavities contain a cube that fills half the 
whole space. The cube is packed into one end, while the bubble occu- 
pies so much of the other end that it appears as though the volume of 
the water were quite small. The apparent great variability of the rela- 
tive amounts of fluid, salt, and space, would, however, make any general- 
izations impossible beyond such as were made by Sorby, that the quartz 
must have crystallized at a temperature below the critical point of water, 
in order to allow of such powerful solvent action as is indicated by the 
large amount of salt in solution. 

At Bemis brook, in the White Mountain Notch, there is a granite with 
so little mica that it is almost granitell. Another, of but very local 


LITHOLOGY. 203 


occurrence in the Notch, is composed of orthoclase, a little quartz, and 
many garnets, and is in composition like granulite, which, however, is 
a fine-grained and stratified rock. 

A variety from Rye is very feldspathic, but when a thin section is 
examined quartz is found, forming a cement that fills all the inter- 
spaces between the well formed and often twinned feldspar crystals. As 
an illustration of the primary formation of the orthoclase, a section of 
this rock is interesting. In Concord, just over the border, in Vermont, 
another example of exactly the same kind is found. These rocks, being 
essentially all orthoclase, furnish an example of a mineral as a rock. 
Masses of granular orthoclase in connection with granitic rocks have 
been often before observed. 

Pudding Granite. A most peculiar granite from Craftsbury, in Ver- 
mont, is included in the collections of the survey, and has been examined. 
This is a biotite muscovite granite, which contains concretions of biotite 
that are quite uniform in size, and usually about an inch and a half in 
diameter. They are spherical or spheroidal in form, and corrugated on 
the surface; and these black shining balls, scattered through the massive 
and light-colored rock, impart to it a most striking appearance. This 
granite is well known and widely celebrated as the pudding granite, a 
name indeed very appropriately suggestive. Desiring to know what 
could form the nucleus of these spheres, I sliced one of them through the 
middle, and of one half made a thin section which contained the centre. 
The interior of this concretion, as a thin section of it appears when 
slightly magnified, is represented in Fig. 4 on Pl. xi. The whole mass of 
the concretion is composed of strongly dichroic biotite, a little muscovite, 
and quartz. The section shows that it has nothing that can be called a 
nucleus, but is only a concretion of mica scales which began to be laid 
concentrically as soon as the first irregular beginning had grown suffi- 
ciently to form a basis. Zepharowich* has described such concretions, 
that occur in the mica schist of Herrmannsschlag in Austria, which in 
the interior are composed of concentric layers, as in this case ; but when 
the concretions were half grown a sudden change took place, and the 


mica began to arrange itself radially, and so continued till the growth 
ceased. 


* Mineralogical Lexicon, Austria, p. 59. 


204 MINERALOGY AND LITHOLOGY. 


Granite Veinstones. In reference to those great veins filled with gran- 
itic minerals, such as occur at Grafton, Alstead, Springfield, Acworth, 
etc., very little need here be said. Their distribution and mode of occur- 
rence have been very completely described by Professors Hitchcock and 
Huntington in Volume II; and the texture of their material is so coarse 
that the study of it is more mineralogical than lithological, and hence 
much has been said in the first chapter of this volume in reference to 
them. In general, it may be stated that these veins were supposed to be 
fissures that were formed deep down in the earth, and into these fissures 
water, percolating through the adjacent strata, entered. This water at 
such a depth must have been under heavy pressure, and heated as well by 
the inner heat of the earth, and hence would have a most powerful sol- 
vent action, and would become heavily charged with the soluble materials 
of the strata. From this water, after entering these veins, the granitic 
minerals crystallized. The water from some distance all flowing into one 
reservoir, minerals rare in the strata were concentrated in the veins; and 
hence, mixed with quartz, orthoclase, and the mica which is so exten- 
sively mined, such minerals as beryl, columbite, and tourmaline, which 
contain rare elements, are common. These veins are characterized by 
large crystals of the granitic minerals; by the occurrence in them of 
graphic granite or pegmatite, which is a granite in which the quartz is 
so arranged with reference to the feldspar as to produce the effect of 
oriental writing; and by the occurrence of a large number of well crys- 
tallized minerals. Remarks additional to those made in the previous 
chapter on minerals, and in the preceding volume by Prof. Hitchcock, 
will be found in the chapter on economic mineralogy. 


SIENITE.* 


Under this head are considered those massive crystalline rocks which 
are composed of orthoclase, with either augite, hornblende, or mica as 
a characteristic accessory. These form an interesting group of rocks, 
which in New Hampshire are much less widely distributed than are the 
granites, and which usually occur in plainly eruptive masses. In some 
of them biotite exists, but they all contain either augite or hornblende, 


* The mode of spelling adopted in the preceding volumes issued by this survey is adhered to. 


LITHOLOGY. 205 


and they will therefore be considered under the two heads of augite 
sienite, and hornblende sienite. 

Augite Sienite. In the neighborhood of the town of Jackson there are 
some gray-colored eruptive rocks, the true nature of which has never 
been understood, because it is only revealed by microscopic examinations 
of thin sections. In the region of the so-called tin mines, rocks are 
abundant which are coarse in texture, and apparently composed of ortho- 
clase and a dark fibrous hornblende. When a thin section of this rock 
is examined, it becomes plain that originally it was a compound of ortho- 
clase and augite, containing also much apatite and titanic iron; but the 
grains that were at first augite, are now in some cases partly, in others 
wholly, altered into a fibrous green mass of hornblende. This horn- 
blende, which results from the alteration of augite, was called uralite by 
Rose, because it was found abundantly in certain localities in the Urals. 
The augite is feebly red in color, and in all its cracks and cleavages the 
incipient alteration is seen, and from the outside the change is steadily 
progressing toward the centres. Fig. 5 on Pl. xi represents a grain of 
augite as it appears under the microscope. The well crystallized apatite 
prisms, the biotite, and titanic iron are also seen. The orthoclase is 
quite opaque, on account of its impure and decayed condition. In some 
cases chlorite and calcite are mixed with the hornblende. The iron 
oxide is often in those diffuse open forms which titanic iron usually. 
takes. Some of the grains are, however, very compact. Almost every 
one of the larger grains of the titanic or magnetic iron is surrounded by 
folize of biotite radially arranged in fan shapes, with the iron oxide as a 
nucleus. One of these grains is represented in Fig. 6 on Pl.xi. Itis pos- 
sible that the mica scales grouped themselves about the grain while the 
rock was plastic, or that they were formed there by a reaction between 
the silicates and the iron oxide. This is no isolated occurrence. In our 
gabbros the biotite and iron oxide are almost always associated, and I 
think that the mica was formed by a reaction in which the iron oxide 
took part, and therefore the minerals are thus associated, 

At a point one mile south-west of Mountain pond in Jackson, another 
warily of this rock occurs, which possesses some other features that are 
very interesting. This rock is finer in texture; the orthoclase is very 
much fresher and clearer; it contains some plagioclase, and also apatite, 


206 MINERALOGY AND LITHOLOGY. 


biotite, magnetite, and pyrite. Like the specimen last described, the 
augite is in process of transformation into hornblende; but in this case 
the resultant hornblende is not the green, fibrous, impure variety that is 
common under such circumstances, but it is a compact, homogeneous, 
brown, dichroic kind. The external hornblende is as pure and possesses 
as definite a cleavage as the augite within; and when the plane of the 
section intersects a grain at right angles to the vertical axis, the cleav- 
ages of the two minerals bear the same relation to one another as do 
the faces of their prisms, if constructed upon the same clino-diagonal as 
has been explained on page 57. Fig. 1 on Pl. 7 is drawn from a section 
of this rock, and shows a grain cut parallel to the base, and another cut 
parallel to the prism. The dichroism is much more marked when one 
Nicol is upon the instrument. 

An augite sienite occurs upon Little Ascutney mountain. In a speci- 
men from Columbia, biotite becomes a prominent ingredient. In the 
last case, some grains of augite are nearly intact; but it may be said, 
that in New Hampshire the augite sienites form a little group of rocks 
which only microscopic study could have identified, since the original 
characters are shown by the study of the cores of the mineral grains. 

Hornblende Sienite. The members of this group are very diverse in 
their appearance, but are easily recognized, and present some very inter- 
esting characters. The augite sienites are entirely free from quartz; 
but in the hornblende sienites the microscope usually detects a little, 
and its presence indicates the relationship of these rocks to the granites. 
A beautiful variety comes from Red hill in Moultonborough. It is com- 
posed essentially of orthoclase, which exists in thin, tabular twinned 
crystal, which mostly lie in one plane, and consequently give to little 
specimens of the rock a stratified appearance. The hornblende, which 
is irregularly distributed, is black, but in thin sections it is deep yellows 
and it encloses more or less biotite in its mass. Microscopic grains of 
blood-red hematite and black magnetite, and crystals of apatite, are de- 
tected, and by aid of polarized light some plagioclase is found to be 
present. Only a very little quartz is seen in some little angular corners 
made by the meeting of the straight edges of the orthoclase crystals. 
Little, partially crystallized grains of sphene are found; and some of the 
grains of hornblende are shown by polarized light to consist of two parts 


LITHOLOGY. 207 


in twin relationship. As there are large accumulations of this rock, it is 
one of considerable importance. 

A hornblende sienite much resembling this comes from Columbia. I 
would like to draw the attention of those interested in microscopic min- 
eralogy to this rock, for in its sections a vast number of cavities filled 
with liquid carbonic acid are found, and, moreover, these cavities possess 
associations that render them very instructive. The rock is white in 
color, spotted with black, and macroscopically only orthoclase and horn- 
blende are visible. In thin sections, plagioclase, biotite, quartz, and apa- 
tite are found; and, moreover, calcite is seen to be a constituent of the 
rock, a mineral which, I think, is not often found in sienites. Quartz is 
present only in small amount, occupying little angular corners; but every 
grain of it is filled with cavities which are quite large, all of which con- 
tain liquid carbonic acid: and this circumstance, in connection with the 
presence of calcite, is very interesting. Knowing that this liquefied 
gas had been found in granitic rocks, I had examined a very large 
number of sections with the idea in view of finding it in our rocks; but 
the tests indicated in all cases nothing but water, and I was therefore 
much pleased to find it in one of the last sections I had to examine, and 
in great abundance. Its presence in connection with the calcite may 
indicate that carbonate of lime was a constituent of the material from 
which this rock was made, and that, at the temperature at which recrys- 
tallization took place, a reaction occurred between the lime carbonate 
and the silicates, producing plagioclase and liberating carbonic acid ; but 
the rock was under such pressure that it could not escape, and it was 
consequently imprisoned in the quartz, which was the last mineral to 
solidify, and the quartz, being small in amount, is correspondingly full 
of the cavities containing the fluid gas. The appearance of a section of 
a quartz grain, as it is seen when magnified 350 diameters, is shown in 
Fig. 1 on Pl. 12, These cavities are often arranged in rows, some of 
which are straight and some curved, and many more cavities are irregu- 
larly strown about. In the larger of them a double line is seen on the 
outer edge, and this line cuts off the corners and irregularities of the 
cavities, and indicates the presence of a very small amount of a second 
fluid, which is probably water. The bubbles are quite large in propor- 
tion to the size of the cavities, and one can immediately perceive that 


208 MINERALOGY AND LITHOLOGY. 


they lie in some other fluid than water; for the circles of their outer 
edges are not broad and black, as are those of bubbles in water, but 
their outlines are simply sharp lines; and this indicates that the bubbles 
are in a fluid, the index of refraction of which is less than that of water. 
On warming the section, the bubbles all simultaneously disappear at the 
temperature of 35° Centigrade, which is a trifle above that at which the 
disappearance has been usually noticed. There are two ways by which 
such bubbles in liquid carbonic acid disappear: the first is, when the 
relative size of the bubble to that of the cavity is small, and then the 
fluid expands and fills the space, below the critical point of the fluid; 
and in this case the bubbles begin to grow small as soon as heat is 
applied. But when the size of the bubble is relatively large, when heat 
is applied the fluid evaporates into it; the bubble grows larger, and at 
the critical point suddenly expands and fills the space. In the cavities 
under consideration, the bubble disappears in this second manner. It 
is very interesting to watch this.* The increase in the size of the bub- 
ble at first can be detected; but the disappearance and reappearance of 
the bubble are instantaneous, and nothing further can be seen than that 
at one instant the bubble is plainly there, and then it is gone, and, on 
removing the source of the heat, it shortly is there again. 

In the figure the mineral above is orthoclase, which includes some 
apatite crystals ; the one on the left is hornblende including a mica scale, 
and on the right there is a grain of calcite. The minutest of the little 
cavities in the quartz, when very highly magnified, are found to contain 
the same fluid. Where the quartz is in contact with the calcite, it ap- 
pears dirty and troubled; but this apparent impurity, with the highest 
magnifying power, is also resolved into a dense aggregate of excessively 
minute cavities. This, too, is significant. 

Besides the carbonic acid, the presence of grains of calcite in an erup- 
tive acidic rock is interesting. It confirms what has been said in regard 
to the mode by which such rocks became plastic. After a pure igneous 
fusion no such combination of minerals as is here found could exist, save 
as a result of some subsequent decomposition. It would seem that if the 


* A little apparatus has been contrived by which a section and a thermometer are warmed together on the 
stage of the microscope. This is accomplished by an electric current in Vogelsang’s contrivance; but in a 
simple and inexpensive apparatus that comes with Mr. Rosenbusche’s microscope that I have described, a cure 
rent of warm air is carried across the stage in a chimney, and is brought in its passage in contact with the 
section and thermometer. 


LITHOLOGY. 209 


carbonic acid were generated as suggested, the conditions of heat and 
pressure were such as to bring about only a partial reaction; and the con- 
ditions under which granitic rocks have been recrystallized, as indicated 
by other circumstances, are just about such as would account for the 
associations observed in this rock. 

Another sienite, which in most respects is exactly like this, occupies a 
dyke in Sandwich. Calcite is absent, and with this absence the quantity 
of carbonic acid decreases. In many cavities in the quartz, however, 
liquid carbonic acid is found, but in the larger number only water and 
the customary crystals of salt. These two rocks are our only ones in 
which I have found this interesting enclosure of liquefied gas, but they 
are remarkable examples. 

On Mill mountain, in Stark, a dark-colored sienite occurs. Macroscop- 
ically, it appears as if wholly composed of orthoclase ; but in thin sec- 
tions considerable hornblende is found in small fragments, which are 
quite thickly distributed: if the rock were light-colored, as are the 
ones thus far described, the hornblende would be prominent enough. 
The feldspar is of that clear grayish waxy variety (adularia) which is so 
prominent in a group of granites which have been described, and to 
those granites this sienite is related. It contains also plagioclase, apa- 
tite, sphene, and epidote, besides a little microscopic quartz. 

A very different kind of sienite is abundant about the town of Albany. 
This is a very fine-grained feldspathic rock which is found in small 
dykes. It is red in color, and full of minute black specks. When thin 
sections are cut, these specks are found to be of a very deep-colored 
hornblende with some little crystals of magnetite, while the mass of the 

_ Tock is composed of small but well defined crystals of orthoclase, in the 
angles between which a little quartz is found. These rocks have com- 
monly been called felsites ; but in no respect do they differ from ordi- 
nary sienite, save in the fineness of their texture. On Sabba-Day brook 
there are favorable localities to see these rocks in place. 


GNEISS. 


Gneiss is in composition exactly like granite, being composed essen- 


tially of quartz and orthoclase as constant constituents, and muscovite. 
‘s 


biotite, hornblende, chlorite, etc., as essential but variabl 


€ consti 
VOL. IV. 27 stituents, 


210 MINERALOGY AND LITHOLOGY. 


and plagioclase, apatite, etc., as accidental constituents. The character- 
istic feature of gneiss is, that it possesses a stratified or laminated appear- 
ance, on account of the parallel arrangement of the individual crystals of 
the essential accessory. Like granite, gneiss is sub-divided, according 
to which accessory it contains, into as many kinds as are characterized 
by different minerals. The difference between gneiss and granite being 
therefore merely structural, all that has been said of granite may, with 
slight modification, be true of gneiss; and hence, though it is one of the 
commonest rocks in New Hampshire, and geologically one of the most 
important, it may be briefly treated here. 

There are many structural varieties of gneiss. Sometimes the acces- 
sory, which is usually mica, lies in flat planes, and the rock appears to be 
uniformly foliated or stratified, while in other cases the mica is in most 
irregular wavy or twisted layers, of most complex structure; and many 
names of varieties have been suggested by peculiar characters of this 
nature. 

The cause of the lamination has been made a study by many eminent 
geologists, and it is by no means certain that in all cases it is to be re- 
ferred to the same one. There are some who still hold that the min- 
eral arrangement is caused by the direct deposition of the minerals on 
the bottom of bodies of water which hold the constituents in solution; 
but the microscopic characters of the minerals and their inclusions, 
being the same as those of granites, point to formation and crystalliza- 
tion under enormous pressures and at elevated temperatures, and ren- 
der this supposition untenable. Again: it is supposed that gneisses 
are made by the recrystallization of such sedimentary beds as argillites 
or clay slates, under the same influence of heat and pressure as made the 
granite, but that these influences were milder in their action, and the 
present condition is the result of the original stratification of the deposits. 
The plane of lamination of the gneiss is often found to be conformable 
with the strata of a region, and it cannot be denied but that original 
lamination may, in some cases, have had its influence. The third sup- 
position is, that the stratified structure was induced by pressure, and by 
retarded movements in the once plastic mass. This theory was first 
advanced by Scrope,* in 1825, to whom the idea was suggested by the 


*Scrope. Craters and Lavas. Your. Geol. Soc., 1856, p. 346. 


LITHOLOGY. ane 


observation of exactly analogous structures in certain lavas and erupted 
masses, which occurred in such circumstances that the origin of the 
structure was plainly evident. To Mr. Scrope, gneiss is “squeezed gran- 
ite.” That mica will thus arrange itself under the influence of unequal 
pressure has been confirmed by Mr. Sorby,* who submitted a mass of 
pipe clay, in which he had mixed some micaceous hematite, to a press- 
ure which extended the mass in one direction; and a subsequent exam- 
ination proved that the scales of hematite had all arranged themselves 
in planes at right angles to the pressure, producing a schistose structure, 
and a more easy cleavage in the plane of the stratification. These exper- 
iments have been of late repeated, with some unimportant variations, by 
Mr. Daubree,f to show the effect of impeded movement. He forced a 
plastic mass under great pressure through an aperture, and thereby de- 
veloped a schistose structure, the laminze being parallel to the walls of 
the opening; and other results of the same nature were obtained. 

All these circumstances demonstrate that pressure which acts in such 
a way as to produce lateral movements may be certainly effective in re- 
ducing any foliated or tabular minerals in a plastic mass to an approxi- 
mate plane; and with our knowledge of the extent to which movements 
have gone on in the crust of our earth, and which have accompanied the 
elevation of mountains and contortion of strata, this circumstance fur- 
nishes the most satisfactory explanation for most of the facts observed, 
If the stratification of gneisses is an induced structure, then it does not 
follow that this stratification should always correspond with the original 
bedding; and the existence of eruptive masses of gneiss, in which the 
Structure cannot be referred to original sedimentary conditions, as has 
been shown by Naumann,t adds weight to the supposition. Mr. Charles 
Darwin has also noticed the gneissoid structure in certain Chilian erup- 
tive granites. Neither does it follow, that if the lamination of the gneiss 
does correspond with the plane of the strata, the lamination is to be re: 
ferred to the stratification of sediments, for the cleavage of some clay 
slates, which is admitted to be due to pressure, very often corresponds 
with the plane of the bedding. If a mass of granitic material is fused or 


* Sorby. Origin of Slaty Cleavage. Edinburg Philos. Four., 1853, p. 144. 
t Comtes Rendus, March 27, 1876. 


} Uber die wahrscheinlich eruptive Natur mancher Gneisse und Gneisse-Crani 
Cone eisse-Granite. Prof. C. F. Naumann. 


212 MINERALOGY AND LITHOLOGY. 


plastic under the influence of great pressures, which are partially due to 
the weight of superincumbent strata and partially to lateral pressures, 
then, in the disturbances which occur in the course of the elevations of 
mountains, the lateral pressures are the ones which naturally are first 
relieved by fractures of the earth's crust; and impeded movements, 
therefore, are very liable to take place in the plane of the strata, and all 
the conditions are fulfilled for the formation of gneisses, with the plane 
of lamination parallel to the strata of the region: this is the position 
which the laminz of most gneisses occupy. All these suppositions are 
quite old, as will be noticed, yet they have received but little attention in 
this country. They are also applicable in the study of the structure of 
other crystalline schists; and in general, though the influence of original 
sedimentation upon rock structure is not to be lost sight of, and although 
rocks of this class are generally considered to have resulted from the 
recrystallization of stratified sediments, it seems certain that the present 
condition of all the crystalline schists is largely owing to the effects of 
the pressures to which we know they have been submitted. 

At the time the last report upon our geology was made (in 1844), the 
metamorphism of the crystalline schists was generally supposed to be 
due to the heat which was communicated to the strata by fiery masses 
of molten material which was’erupted through them. In a small dyke 
of trap or granite, cause sufficient was seen to spread metamorphism far 
and wide through the surrounding strata. This idea is not yet entirely 
passed away, although the real effects, which can be produced in sedi- 
ments by the influence of zmmense eruptive masses by simple contact, 
are evidently small, as can be seen in many places,—for example, in the 
Connecticut valley, where the great dykes of diabase cut the red sand- 
stones. The microscope points to the action of the same forces in the 
recrystallization of the schists as in the case of the granites, though 
acting perhaps less efficiently in their fusion. 

Muscovite Gneiss. Pure muscovite gneiss, like granite, is compara- 
tively rare, because the entire removal of iron from sediments is usually 
attended by the removal of so many other constituents as to produce the 
composition of some other rock. A bed of pure muscovite gneiss occurs 
at Chesterfield. The rock is white, glistens with its mica, and contains 
many light red, poorly crystallized garnets. The mica lies in very reg- 


LITHOLOGY. 213 


ular and even planes, but the individual laminz are much bent and 
twisted. A specimen from Rye contains numerous microscopic apatite 
crystals, which are visible in thin sections. 

Biotite Gneiss. This gneiss is much more common. Like all our 
gneisses, it varies in structure from the very schistose kinds to those 
in which the lamination is invisible in small specimens, and only faintly 
visible in large masses, and which are called gneiss granites. I will men- 
tion only a few prominent peculiarities of individual specimens, none of 
which are uncommon. A gneiss from Swanzey is very uniform in its 
texture, and a thin section shows that its feldspar is largely oligoclase. 
It would be called oligoclase gneiss. It contains garnet and epidote, and 
also a few crystals of apatite. Some grains of oligoclase are twinned in 
two directions, and the strize are very fine, making most beautiful objects 
of the crystals. The biotite is very deeply colored, and strongly dichroic. 
A gneiss that underlies the schists on the Saco river is very feldspathic, 
but the feldspar is mostly orthoclase. It contains magnetite, and also 
microscopic cubes of pyrites. A variety from Eagle cliff is pseudo-por- 
phyritic in structure, some of the crystals of orthoclase being very large. 
A specimen from Tripyramid is remarkable for the large number and 
large size of the fluidal cavities in its quartz. It also contains large 
grains of titanite. Another specimen from the same locality contains 
numerous microscopic scales of hematite, which in the thin sections ap- 
pear of a deep red color. A specimen from Holderness is very black on 
account of the preponderance of biotite. A kind quarried at Enfield is 
very light, because the amount of mica is small. A variety very coarse 
in texture comes from Wolfeborough. A variety with a very dark green 
shade comes from Whitefield. This shade appears to result from the 
original color of the mica, and not, as it often does, from decomposition. 
All these peculiarities are combined in various ways in other specimens, 

Biotite Muscovite Gneiss. This is the most common variety of gneiss, 
and the larger number of our specimens are classed here. Prominent 
in this group are the old pseudo-porphyritic gneisses that character- 
ize the formations that are referred by Prof. Hitchcock to the Lauren- 
tian. These gneisses are mostly dark in their color, since the biotite 
preponderates over the muscovite. In them large orthoclase crystals, 
which are often two inches long, are developed. These crystals are com- 


214 MINERALOGY AND LITHOLOGY. 


monly twinned, and usually, though not always, lie with their long direc- 
tion in the plane with the mica. Very often these crystals are ill formed, 
and lenticular in shape; and the black mica surrounding such crystals 
gives to them the appearance of eyes, whence the German name “augen 
gneiss.” Such gneisses occur at Newbury and Antrim. This formation 
reaches it northern limit at Bethlehem. At this point the gneiss is much 
lighter, on account of the greater abundance of muscovite. At New 
London some of the mica, by decomposition, has acquired a brilliant 
golden yellow color. Inexperienced persons have often had their curi- 
osity excited by such mica in certain of our gneisses. This porphyritic 
gneiss is a very important and widely distributed rock. 

The members of the group of rocks to which Prof. Hitchcock has 
given the name of Bethlehem gneiss belong mostly in this place. They 
are in general characterized by a faint green tint that is due to the pres- 
ence of some chlorite, which is a decomposition product, and which allies 
them to the protogene gneiss. At Hanover this rock contains epidote, 
and crystals of tourmaline are found by an examination of thin sections. 
It also contains pyrrhotite, which does not appear to be an objection 
to its employment as building material,—for the base of the fine Culver 
Hall, one of the Dartmouth College buildings, is made of it, and none of 
the stains are found which some expected would shortly appear. A 
specimen of this gneiss from Bethlehem is almost white, and only faintly 
and irregularly streaked with micaceous layers. 

Most numerous appearances are presented by gneiss, which are de- 
pendent on the color, structure, and arrangement of its constituents. A 
kind from Carroll is what is called wavy gneiss, because the layers of 
mica are undulating. Such and numerous other structures are induced 
by the same agencies that crumple up strata. A kind from Marlow con- 
tains andalusite, and also many red garnets, which dot the black surface, 
making a very pretty rock. A gneiss from Ossipee contains numerous 
and quite perfect rhombic muscovite crystals. And so we might con- 
tinue ;—but the causes of the great number of variations to which gneiss 
is subject are self-evident, and need no elucidation. 

Hornblende Biotite Gneiss. In some gneiss, hornblende is visible to 
the unaided eye, as, for example, in one from Frankenstein cliff; but 
more often it is found, by the aid of the microscope, as a constituent of 


LITHOLOGY. 215 


rocks which are apparently biotite gneiss. In a thin section of a gneiss 
from Mt. Franklin in Swanzey, deep brown hornblende, epidote, garnet, 
and plagioclase, in addition to the other regular constituents, are found. 
In a handsome black gneiss from Littleton, the proportion of ingredients 
is reversed, and the biotite almost disappears, while hornblende becomes 
very prominent. In thin sections this hornblende is very deep green in 
color, and plagioclase and epidote are found. 

Protogene Gneiss, Associated with the chloritic granites, in the same 
localities along the Connecticut valley, there are green gneisses which 
differ from the granites only in structure, and need no further considera- 
tion. These are the granitic members of the group of greenstones which 
are characteristic of the valley. In this region, hornblendic and chloritic 
rocks are particularly abundant; and it is interesting to note that the 
associated granites and gneisses partake of the same general nature. 

By the gradual withdrawal of the feldspar from gneiss, this rock ap- 
proaches in composition towards mica schist, which is next considered. 


MICA SCHIST. 


This is essentially a schistose mixture of quartz and mica; but varia- 
tions in the structure, in the size of the constituent crystals, in the pro- 
portion of ingredients, and in the presence of accessory minerals, make 
of the rocks of this class a most diversified group. The mica is often 
muscovite, often biotite, and often both. The usual accessories are an- 
dalusite, cyanite, fibrolite, staurolite, garnet, and tourmaline, which are 
often so abundant as to give a character to the rock. The following are 
the principal varieties : 

Ordinary Mica Schist. In the most common kinds of this rock the 
mica is in quite large scales, and as the rock cleaves in the plane of its 
lamination, the glistening mica is much the most prominent ingredient. 
The quartz is most plainly seen on the rough fractures across the lam- 
ina, where it appears in lenticular grains about which the mica bends 
Though biotite is usually present, muscovite predominates. The mica if 
tested, usually gives some water, as does margarodite. In thin seedons 
under the microscope, magnetite, apatite, orthoclase, hornblende and 
chlorite are very often found. Tourmalines abound in the sehen on 


216 MINERALOGY AND LITHOLOGY. 


Mt. Washington. The lamination is sometimes quite even; but, again, its 
plane is waved, twisted, bent, and knotted in various ways. This variety 
of mica schist is the ordinary one among the highly crystalline strata. 

At some points, as, for example, at Bedford, the mica is in little scales, 
and is mostly biotite. This brings the quartz into prominence by the 
contrast of color. Sometimes, as at Wakefield and Epping, the crystals 
of the ingredients are so small and so intermingled, that the rock becomes 
nearly massive, and resembles certain basic eruptive rocks in hand speci- 
mens. A glance with the microscope tells the true nature. This type 
is more characteristic of the valley formations, where all the rocks seem 
to have been recrystallized under gentler agencies than were those which 
have heaped up the most highly crystalline strata in the mountains. 
Some schists in this valley appear to be half fragmental in type, and 
consist of schistose masses of sand bound together by scales of mica, and 
resemble itacolumite in a degree. 

Andalusite Mica Schtst. In this rock crystals of andalusite are promi- 
nent and characteristic. Such schists abound in the mountainous re- 
gion. Rarely the andalusite is quite well crystallized. Often it exists in 
rounded nut-like forms in the rock, which are very hard, and become 
prominent on weathered surfaces on account of their greater ability to 
resist decay. Often it is in long rude imperfect crystals, which are 
heaped together in tangled web-works. These crystals often decay in a 
peculiar manner. Sometimes the centre rots away and a cylinder is pro- 
duced, and sometimes both centre and outside resist while the rest of 
the crystal gives way. At some points the macled structure is very 
prettily developed, but where this is the case the schist loses its marked 
micaceous character and becomes argillitic. The condition of internal 
alteration, which is shown by the microscopic structure of andalusite 
crystals, has been already pointed out on page 106. In a microscopic 
section of a schist from the Notch, it is seen that besides the large crys- 
tals there are very minute crystals of andalusite. 

Fibrolite Mica Schist. Mica schist full of fibrolite is abundant in the 
same regions as is andalusite schist. Fibrolite appears to be much more 
stable than is andalusite, and consequently its fibres appear very clear 
and fresh in thin sections. Fig. 3 on Pl. 8 represents a section of a fibro- 
lite schist from the Notch, as it appears between crossed Nicols. In the 


LITHOLOGY. 217 


figure the planes of vibration of the light are represented by the cross 
lines. The fibrolite pierces the scales of biotite, and takes its straight 
course, regardless also of the quartz, and its orthorhombic character is 
shown by the circumstance that all the fibres which are parallel to the 
plane of either Nicol are black. On the top of Mt. Washington fibrolite 
is very prominent in the schists, and the masses that are formed by 
aggregations of its fibres are quite striking in appearance. 

In the neighborhood of the Crystal cascade a fibrolite schist occurs, 
which is black in color, and so nearly massive that it has never been dis- 
tinguished from the diabase that is found near it. The fibrolite is, how- 
ever, easily seen on close examination, and a thin section shows that the 
rock is a fine mixture of quartz, biotite, and muscovite, with less of mag- 
netite, pyrite, and chlorite. Through this mixture fibrolite and garnets 
are sprinkled. Many of the garnets are zoned by the arrangement of 
impurities. They mostly have clear centres and impure rims. This rock 
appears spotted on fresh fracture surfaces, and darker parts are included 
in the lighter in such a way that it has been called a trap conglomerate. 
It being understood that the rock is of sedimentary origin, its structure 
is not peculiar, for such features are not uncommon in crystalline schists. 

Staurolitic Mica Schist. Mica schists, in which staurolite crystals 
are so abundant as to give character to the rock, occur at Enfield and 
many other towns along the Connecticut river. The staurolites are usu- 
ally but poorly crystallized, though exceptionally good crystals, which 
are sometimes an inch in diameter, are found. As mica schist gradually 
loses its micaceous character and becomes argillitic in a formation at 
Charlestown, the staurolite becomes macled, and presents itself in the 
peculiar form that is described on page 110. In the mica schists of the 
Connecticut valley, the staurolite crystals are usually large and twinned, 
In the argillitic schists, they are often very small and simple. 

Garnetiferous Mica Schist. Mica schists, characterized by the pres- 
ence of many garnets, are abundant. At Springfield, well crystallized 
garnets compose more than half the bulk of some schists. In other 
rocks, fewer but still large crystals are found; and in many rocks, which 
are not characteristically garnetiferous, this mineral occurs abundantly 
as a microscopic constituent. Garnets are found in the same schists 


with andalusite, staurolite, etc. 
VOL. Iv. 28 


218 MINERALOGY AND LITHOLOGY. 


ARGILLITIC MICA SCHIST. 


In mica schist, by insensible degrees the scales of mica lose their in- 
dividual character, till at last nothing that can be distinctly recognized 
as a scale or crystal can be seen. All the constituents are very fine, 
and the rock becomes argillitic mica schist. The rocks of this class, 
however, possess a glistening lustre which is suggestive of mica, and 
which is due to its presence, as the microscope indicates. With a high 
magnifying power, they are seen to be composed of an entirely crystal- 
line mixture of quartz, feldspar, mica, and chlorite, with various accesso- 
ries. They are distinguished from real argillites and slates by this crys- 
talline type, but the metamorphism has been of such a gentle nature that 
it has left the ingredients in a fine condition, and has not entirely re- 
moved the argillitic character. The condition of the ingredients and 
the presence of accessories create many variations in this rock. When 
much chlorite is present, the schists are greenish in color. Excessive 
fineness and a preponderance of the micaceous ingredient give a soapy 
feel to the rock, Contortion of the laminz produces wavy, woody, and 
other imitative structures. But under the microscope, these rocks are 
all essentially alike, and are characterized by their very fine yet entirely 
crystalline type and micaceous appearance. Here are included the rocks 
called phyllite, and the larger part of those called hydro-mica slate. The 
rocks called by the Germans old clay slates (urthonschiefer), as distin- 
guished from the newer slates, are of this class, and many local names 
have been given to varieties. Just as intermediate kinds bind this rock 
to mica schist, so other varieties, which are not so entirely crystalline, 
bind it to the clay slates. In general, however, it is very well character- 
ized, and quite distinct from these related rocks. 

Argillitic mica schist is very abundant in New Hampshire, particu- 
larly in the Connecticut valley. For special examination, I have selected 
a specimen from that region, which is as typical as possible of the whole 
group. It is what is called by Prof. Hitchcock the Lyman schist, which 
by itself composes the larger part of a formation. The specimen was 
collected at Woodville. It is gray in color, very schistose, but not at 
all friable. It is in appearance perfectly homogeneous, and no constit- 
uent can be detected with the eye or pocket lens. It is somewhat glis- 


LITHOLOGY. 219 


tening in its lustre, ‘and rather soapy in its feel. I analyzed the rock, 
and the following was the result: 


Silica, . : ; 2 : : ee ee 60.49 
Alumina, é : a 3 ‘ . . . . A 5 19.35 
Jron sesquioxide, . ‘ : : ‘ ° ; ‘ 2 z 48 
Iron protoxide, , ‘ i 5 : ‘ ‘ : § 2 5-98 
Lime, 3 5 . F - z ' re 3 3 ‘ 3 1.08 
Magnesia, F 3 : 2 é ‘ , . ‘ I A 2.89 
Soda, ‘ A , . é ‘ q 5 ad j ‘ 2.55 
Potash, . r ‘ 3 : ‘ : - ‘i é F 3.44 
Water, . . : : F . 3 a . ‘ : f 3.66 

99-92 


This analysis indicates that the rock has the composition of an ordi- 
nary clay, minus the larger part of its water. It is plain that, acccording 
to the efficiency of the forces that act in recrystallizing such sediments, 
material of this composition could be converted into a slate, a granite, a 
porphyry, or one of several other rocks. That such rocks as these 
schists are particularly characteristic of the valley, is to be referred to 
the feeble action of the same metamorphic agencies that in the interior 
regions have created the coarsely crystalline type, which here is largely 
replaced by the fine-grained and the half fragmental type. 

When a thin section of this schist is examined with the microscope, it 
appears to be made of an extremely fine aggregate, but with a high mag- 
nifying power it is seen to be composed of white transparent quartz and 
a fine foliated substance, most of which is apparently mica in a very fine 
state of division. These parts are brought into sharpest relief in polar- 
ized light, for the micaceous constituent assumes the brightest colors. 
As the section is revolved between crossed Nicols, the folize become dark 
when in the plane of either Nicol, as does mica, and as the foliz are 
mostly in one plane they nearly all become dark at once. The examina- 
tion of the section shows besides, that some green chlorite, some trifling 
bits of calcite, and minute grains of iron oxide are scattered about, and 
some bits of the granular substance have the white semi-transparent 
appearance of feldspar. A section of this rock, as it appears when mag- 
nified 600 diameters, is represented in Fig. 2 on Pl. 12. It is introduced 
to show that these rocks, though so fine in texture, are composed of 


220 MINERALOGY AND LITHOLOGY. 


recrystallized minerals, and do not share at all the fragmental character 
of the rocks like clay slates, which are composed of the merely cemented 
particles that constitute clay beds. To these rocks they are, in composi- 
tion and physical characters, so néarly related that they are appropriately 
termed argillitic mica schist, and they form the connecting link between 
mica schist and argillite. 

No analysis can be called typical of such rocks as these, for the pro- 
portion of silica in them is as variable as it is in beds of clay. With 
further increase of the micaceous constituent, the rocks become more 
glistening in lustre and softer to the feel. A schist of this nature at 
Lyman is commonly called the copper schist, because it contains con- 
siderable chalcopyrite and bornite. Pyrites is a common constituent of 
this class of rocks. _ ; 

Some of these schists are very dark in color, and thin sections of such 
are filled with an opaque, apparently amorphous substance. A specimen 
from Dalton is an example. When a fragment of this rock is heated, 
the coloring material is destroyed; and this indicates that the black par- 
ticles are of some bituminous substance. In these black varieties the 
glistening appearance is often nearly absent, but, with a pocket lens, in 
no variety can the mica be more clearly distinguished. 

Like mica schist, this rock species is varied by the abundant presence 
of certain accessories. As often as mica schist is characterized by anda- 
lusite crystals, so often is argillitic mica schist by chéastolite; and chiasto- 
lite seems to be confined to rocks of this class,—for when the micaceous 
character of the rock is well defined, the macled character of the crys- 
tals is absent. A macled variety of staurolite characterizes an argil- 
litic schist at Charlestown, and being an isolated occurrence this szau- 
volite schist has attracted much attention (see p. 110). At this locality 
the argillitic rock gradually passes into a well defined mica schist, and, 
as before stated, with this passage the macled structure disappears. 

Some other striking peculiarities in the nature of this rock are seen in 
certain localities. At East Hanover, for example, some of the schists 
are mottled by what are apparently pebbles of various sorts and sizes 
that have been flattened out between the layers. This circumstance was, 
I think, first noticed by Prof. E. Hitchcock,* in 1833, and was mentioned 


* On the conversion of certain conglomerates into mica schists, etc. E. Hitchcock, Am. Your. Science, 
ii, vol. 31, p. 372. 


LITHOLOGY. 221 


by him in his report on the geology of Massachusetts. Subsequently, 
aided by his son (the chief of our survey), the subject was more thor- 
oughly investigated by him, and it was found that the flattening of pebbles 
between layers of schistose rocks had taken place at many localities, and 
that a geological significance was to be attributed to the circumstance. 
Since that time analogous phenomena have been found all over the 
world, so that it is no longer a novelty; but it is well understood that 
pebbles of quartz, or of other substances, may be variously altered in 
form by the processes of rock metamorphism, which are not of that 
degree of efficiency that entirely obliterate all signs of the original con- 
stitution of the sedimentary mass. In limestones, well known fossils, 
which are flattened and contorted, are found between the strata; in con- 
glomerates, two pebbles, one of which has forced itself half way through 
its more yielding neighbor, are sometimes found in juxtaposition ; and 
in a mixture of fine and coarse material, the finer part may be converted 
into mica schist, while the pebbles do not enter into the mass, but are 
softened and flattened into thin discs. These facts are again brought 
forward by those who think that the stratification of such rocks is par- 
tially or wholly due to pressure acting at right angles to the plane of 
the lamination; and they point very definitely to the circumstance that 
though, in these rocks now under consideration, the stratification is 
parallel to the original bedding, yet pressure must be considered as a 
very efficient agent in inducing a schistose or finely laminated condition. 

At some places in New Hampshire the strata of the schistose rocks 
are most curiously broken. On Mt. Pequawket a huge breccia occurs, 
which is composed of large broken and angular fragments of argillitic 
mica schist. These fragments lie in all directions, and at all angles with 
one another, but are firmly consolidated into a compact mass. This is 
not so difficult to understand, for at some other points the fragments are 
found cemented together by a felsitic mass, and at others quartz por. 
phyry constitutes the bulk of the rock, and in it the fragments of schist 
lie embedded. It therefore appears that the strata of schist were crushed 
and broken by the force that opened a way for the eruption of the 
quartz porphyry, which forms a large part of the mountain. But the 
cause of the broken condition of these schists is not always so plain. 


In the south-western part of the state, such appearances are not rare 


222 MINERALOGY AND LITHOLOGY. 


Dr. Jackson describes one such broken mass of slate in Gilford, in 
which the strata were likewise entirely broken to pieces. The effect was 
attributed to an immense iceberg which was stranded there while the 
land was submerged, and by its movements and its mighty weight broke 
up the rocks. Although such accidental causes might produce these and 
many other results, in the more general and efficient action of the great 
movements that have taken place in the crust of the earth, a more relia- 
ble explanation is found for all such varied and often peculiar effects. 

Novaculite. (Oil Stone.) This is a variety of schist in which the 
quartz very largely predominates, and the rock therefore loses its schist- 
ose character, becomes nearly massive, and breaks with a conchoidal 
fracture. It is usually of a gray color, and forms layers of greater or less 
thickness among the other schists. These rocks have not been well 
understood, and have been called quartzite, siliceous limestone, and 
felsite; but the microscope shows that they possess the same structure, 
and the same ingredients arranged in the same way, as the argillitic mica 
schists, and that the proportion of ingredients is all that constitutes a 
difference. 

As tpyical of these rocks, a specimen from Littleton will be described. 
This rock is light gray in color, massive, and so fine in its texture and so 
homogeneous, that no ingredient can be macroscopically detected. It 
looks like a gray felsite, and like felsite it fuses before the blow-pipe. A 
study of a thin section shows that it is an excessively fine-grained mixt- 
ure of much quartz and little orthoclase, among which the little fibrous 
and scaly crystals of mica that characterize the argillitic mica schists are 
thickly scattered; but these scales are much smaller, and do not consti- 
tute an ingredient of any importance. Grains of calcite are also seen. 
The constituent minerals bear a recrystallized character, and none of 
them appear fragmental. The rock has, therefore, all the characters of 
argillitic mica schist; and the massive condition is due to the excessive 
amount and fineness of the quartz, and the small amount of the mica- 
ceous constituent. Its fusibility, which first caused it to be called felsite, 
is in part due to the calcite, which forms a flux for the silica, and in part 
to the orthoclase, for it is well known that a mixture of quartz and ortho- 
clase will fuse as easily as orthoclase alone. A specimen from Tamworth 
is black, and contains chlorite and iron oxide. Other specimens differ in 


LITHOLOGY. 223 


color and in proportion of ingredients; but I think this description may 
be regarded as representing them all fairly. This is the novaculite, or 
oil-stone, that is so highly prized for sharpening tools. 


QUARTZ SCHIST (QUARTZITE). 


Almost all kinds of schists, by the elimination of the minerals which 
characterize them, graduate into quartz schist. Very siliceous varieties 
of mica schist, argillitic schist, chlorite schist, etc., stand between quartz 
schist and these various rocks; and therefore this rock, which typically 
is a pure schistose mass of quartz, possesses a variety of characters that 
are given to it by its accessories, and which relate it to other rocks 
that have been and are to be described. The rocks abound in the Con- 
necticut valley and geologically related areas. They show very various 
degrees of metamorphism; and although, as a rule, their structure indi- 
cates a complete recrystallization of the materials that formed the sedi- 
mentary beds, still cases are not wanting where remains of the frag- 
mental character are maintained. It is understood, that in this place the 
rocks with the latter character are not considered, but are included 
among the descriptions of half fragmental rocks that follow. In texture, 
all grades occur between coarse granular and cryptocrystalline varieties ; 
and in structure, all grades between very schistose and almost massive 
rocks. 

The most common kind of quartz schist is micaceous. A white mass, 
consisting of granular quartz, shows on its schistose cleavages flakes of 
a glistening mica, which is usually all muscovite, and rarely is partially 
biotite. This is in contrast to most of the micaceous rocks; for though 
a little alumina and potash may remain, usually but little iron exists 
in such highly siliceous sediments. The reverse is, however, shown by 
a specimen from Newcastle, in which a very fine-grained quartzite is 
traversed by multitudes of black, parallel lines, which on investigation 
are found to be made by the arrangement of minute grains of magnetite. 

ad micaceous quartz schist from Hinsdale is composed of a very pretty 
bluish Epaleseen quarts and its mica is more fibrous than foliated. In 
Shite other varieties, the presence of mica is only indicated by that glis- 
tening lustre that characterizes the argillitic mica schists, 


224 MINERALOGY AND LITHOLOGY. 


Orthoclase often appears in these rocks, but only as an unessential 
accessory, though sometimes it is macroscopically visible. Plagioclase 
is not at all rare. Apatite is found ina section of a Portsmouth quartz 
schist. Pyrites is a very common ingredient. It occurs in both micro- 
scopic and macroscopic crystals, which though so small are often very 
well formed. 

A quartz schist from Connecticut lake is very fine in its texture, and 
contains, as accessories, calcite, plagioclase, biotite, magnetite, and chlo- 
rite. Calcite is not rare in these siliceous schists. Its common pres- 
ence in such acidic rocks points toward the gentle action of the forces 
that have effected their recrystallization. This is apparent in all the 
rocks of the region where these schists are most common. 


GREENSTONES. 


Under this head it is proposed to describe those interstratified rocks 
which are so prominent in the valley of the Connecticut, which are inti- 
mately associated together, and which, in common, possess a more or less 
green color that is induced by the presence in them of hornblende or 
chlorite. No especial significance is intended to be attached to the 
word greenstone, though efforts have been made to dignify it with a 
meaning. I use the word simply to connect together for discussion cer- 
tain rocks, which in any lithological classification would be widely sepa- 
rated. As warrant for their union under this term, there is their close 
geological association, and the precedent established by all those who 
have written upon the geology of the valley region, who have so con- 
stantly spoken of greenstone that all will understand what rocks are here 
referred to. 

All along the valley of the Connecticut, from its source to its mouth, 
there are large accumulations of green rocks, and so characteristic are 
they of the region, that the area has always been colored green on geo- 
logical maps. These rocks are of several kinds, and are interstratified 
with one another, with argillitic schists and with other related rocks. 
One kind is the light green chlorite schist, which the microscope shows 
is essentially composed of minute grains of quartz with chlorite. Another 
is the amphibolite, which is composed of amphibole mixed with more or 


LITHOLOGY. 225 


less quartz. In others a triclinic feldspar becomes prominent, the schist- 
ose character disappears, and a diorite composed of plagioclase and horn- 
blende results. To these three species,—diorite, amphibolite, and chlorite 
schist,—all these greenstones may be referred, but the variations in the 
proportion of ingredients and the presence of accessories diversify the 
rocks to that extent which is to be expected in sedimentary formations. 
They form a group which has excited much interest, and some general 
remarks in reference to them will be made after they have been described. 

As a formation these rocks are widely distributed. Dr. Hunt de- 
scribed their occurrence and geological relationships in his report on the 
geology of Canada, and Prof. Dana* has pointed out their stratigraphical 
relationships in the New Haven region. Mr. T. B. Brookst has found 
them widely distributed over the southern shores of Lake Superior, and 
has described and classified them. Our particular formation was first 
noticed by Prof. E. Hitchcock, who called them all greenstones. Prof. 
Hitchcock, of this survey, has studied our formation with great care, and 
referred the rocks to the Huronian age. Other investigators have deter- 
mined like formations also to belong to the Huronian. In Europe, rocks 
thus associated frequently build formations; but I think that enough 
has been said to indicate that these rocks form a defined group, the 
members of which are very likely to be associated together, and that 
therefore anything that can be deduced from the study of our rocks may 
be quite generally applied. 


METAMORPHIC DIORITE. 


This is essentially a compound of hornblende and a triclinic feldspar, 
and is therefore of the same composition as the rock which has been 
described as basic eruptive. This variety, however, is found interstrat- 
ified with schists of various kinds. It bears at times marks of stratifica- 
tion itself, and has been repeatedly shown to belong to the formation in 
which it occurs, although the existence of diorites other than eruptive 
is not as yet generally admitted. It is not at all surprising that two rocks 


of the same composition should originate in very diverse ways, for among 


* American Fournal of Science, iii, vol. xi, p. 119. 
ft American Fournal of Science, iii, March, 1876. 
VOL, IV. 29. 


226 MINERALOGY AND LITHOLOGY. 


rocks other than basic this is known to occur constantly; but we may sup- 
pose that when this does happen, the two rocks will have certain general 
characters stamped upon them by the different forces that have acted 
on them, and which will distinguish them from one another. I shall, 
therefore, at first, point to certain fundamental differences in the micro- 
scopic character of eruptive and metamorphic diorites, which, so far as 
New Hampshire rocks are concerned, are general, and which therefore 
may be regarded as confirmatory of the stratigraphical researches that 
have been already referred to. 

In examining sections of eruptive diorites, the sharp, definite crystal- 
lization of the hornblende is the first thing noticed. It may not assume 
a definite form, but if irregular, the grains are compact, and possess well 
defined outlines. As opposed to this, the hornblende of our metamor- 
phic diorites, as seen in thin sections, is found in most diffuse and un- 
compact forms, which are in marked contrast to those of eruptive dio- 
rites. Instead of defined crystals and compact grains, we have fringed 
masses, aggregates of needles, and minute, disseminated crystals, as the 
characteristic condition. It will be shown that the agencies which have 
been effectual in recrystallizing these rocks were gentle in their action; 
and this microscopic distinction is what might be expected as the result 
of a gentle metamorphism as compared with an igneous fusion. This 
difference may be noted on comparing the sections represented in Figs. 
3 and 4 on Pl. 12, with the sections of eruptive diorites represented in Figs. 
5s and 6 on Pl. g. There are other differences which are less funda- 
mental, but still general in New Hampshire. The hornblende of the 
eruptive diorites is deeply colored, appears black in the rock, is strongly 
dichroic in sections, and gives no brilliant colors between crossed Nicol 
prisms. The hornblende of our greenstones is not so deeply colored; it 
is light green in thin sections, is not so dichroic, and gives brilliant polar- 
ization colors. In other words, the hornblende of the eruptive rocks is 
the so-called basaltic variety; and of the metamorphic rocks it is the 
common variety. The analysis of the hornblende of the green diorites 
has been given on page 66. This analysis was made on quite pure mate- 
rial, and shows that it is the aluminous variety called pargasite, a fact 
which has been often enough shown before in studies on like rocks. 
I would like to call attention in this connection to the analyses of horn- 


LITHOLOGY, one 


blende and: pyroxene, which were made with the idea of indicating why 
hornblendic rocks are so predominant among the stratified schists in 
New Hampshire (see p. 65). Among these analyses one will be found 
which indicates the composition of the hornblende from the eruptive 
diorite at Dixville notch. A comparison of this with the pargasite will 
give the essential chemical differences between the hornblende of our 
two kinds of diorite. 

Some of the metamorphic diorites are free from quartz, and some in- 
clude quartz in their composition. On this basis, they are sub-divided 
into plagioclase diorites, which are compounds of plagioclase and horn- 
blende, with certain accessories, and quartz diorites, which contain quartz 
in addition, but not in preponderating amount. 

Plagioclase Diorite. These rocks are light green in color, and are 
granular and massive. Sometimes they form thick beds, and sometimes 
only thin strata among other schistose rocks. They are much less nu- 
merous than the quartzose varieties, and in composition they are very 
complex. Ina specimen from Pittsburg the hornblende is in such large 
grains that it can be macroscopically recognized. Thin sections show 
that this hornblende is of a light green kind, in which the dichroism and 
absorption are marked. As usual, the grains of hornblende are fibrous 
in their nature, and are all fringed out on the edges. In some grains 
which are cut at right angles to the prism, the characteristic cleavage is 
very plain; but other grains appear to be made of a mere mass of needles, 
and the fibrous structure prevents any such character as cleavage from 
being recognized. I have represented a section of this rock in Fig. 3 on 
Pl. 12, but have introduced only the most general features that character- 
ize it, and have left out the rare or accidental constituents. The mass of 
the white portion of the rock is a triclinic feldspar, which is characterized 
by the wide bandings that polarized light develops. These bands are 
often indistinct, on account of the decomposition to which the feldspar is 
very subject. As a result of this decomposition, epidote is a never-failing 


constituent of the rock. This epidote is light yellow, somewhat dichroic 


and gives most brilliant colors in polarized light. By its abundance, and 
: ? 

by the presence of multitudes of little hornblende crystals, and of other 

small minerals, the bands of color in the feldspar'are sometimes nearly 


obscured. Peculiar forms resulting from the decomposition of titanic iron 


228 MINERALOGY AND LITHOLOGY. 


are also characteristic of this rock. Gray masses filled with remnants of 
the black iron oxide are scattered about, and in some cases the titanic 
iron has entirely disappeared, leaving only the gray material. This sub- 
stance is usually traversed by lighter lines, which being determined by 
the cleavage or lamination of the original mineral, are regular in their 
directions, and therefore symmetrical forms are produced which, in some 
cases, are remarkably like fragments'of organisms. One of these forms, 
which is represented in Fig. 5 on Pl. 2, has been already spoken of. 
Titanic iron is a mineral which is not easily decomposed; but its decay 
is a characteristic feature of the diorites, and has resulted from a reaction 
which has taken place between the lime, separated from the feldspar, 
and the titanic acid (see p. 40). The iron has perhaps entered into the 
composition of the chlorite, which is sparingly present. Some sections 
of this rock contain grains of augite. This augite is of a light red color, 
but I have not introduced it into the figure, for although occasionally 
present in quite large grains, it is in no sense characteristic of the rock, 
and is usually absent. 

A specimen from Littleton is much more compact, and is so fine in 
texture as to appear like a homogeneous mass. In thin sections it is, 
however, nearly the same as that last described, but is more decom- 
posed, and hence contains more chlorite, epidote, and altered titanic” 
iron. Biotite and calcite are also present. 

These two specimens from Pittsburg and Littleton, both having a 
specific gravity of 2.96, were analyzed with the following results : 


Pittsburg. Littleton. 
Silica, . : P ‘ a é ‘i ; 48.79 45.56 
Alumina, . ‘ : i ‘i : : ‘ : 16.97 16.57 
Iron sesquioxide, . . é . é : j 1.69 36 
Iron protoxide, : : é ‘ A e . 8.97 9.40 
Manganese protoxide,_ . : ‘ ‘ ‘ . .20 +20 
Lime, . 2 : S é 3 : é ‘ 9-98 8.01 
Magnesia, : A ‘ . ‘i A : bs 6.98 10.34 
Potash, ‘i ‘ 3 F 3 é . aiverers 1.20 
Soda, 3 i ‘ ‘ . : 5 , : 3.30 2.55 
Titanic acid, . 5 : . , ; i ‘ I.10 1.20 
Water, . - 7 3 ‘ . : . ‘ 2.65 3.93 
Carbonic acid, ‘ F ‘ z p ‘ 5 ee 1.02 


100.63 100.34 


LITHOLOGY. 229 


On account of the complexity of this rock, it would be difficult to cal- 
culate what species of feldspar is present. As the percentage of silica 
in the rock is below that shown by the analysis of its hornblende, it cer- 
tainly is quite basic. The chief value of these analyses is in showing 
the ultimate composition of the original deposits from which these rocks 
were made, and it is interesting to note that the analyses do not differ in 
any respect from those of certain basic eruptive rocks. 

Quartz Diorite. By far the larger part of our green diorite is quartz 
diorite. In some specimens, quartz is present only in the most insig- 
nificant amount, but in others its quantity is increased till it greatly pre- 
ponderates, and the dividing line between diorite and amphibolite is 
reached. As distinguished from the quartz-free diorites, these rocks 
appear to be more fresh and undecomposed; chlorite is not so common, 
and augite is entirely absent. Their color is darker, and the hornblendic 
character is more evident to the unaided eye. I have selected for illus- 
tration a quartz diorite from Lisbon. The rock is dark green in color, 
but is spotted with white spots, which can be in part recognized as feld- 
spar by the cleavage. In a thin section, the hornblende appears in large 
fibrous masses, in bunches of radiating neeHes, and in minute separate 
crystals. This hornblende assumes the most brilliant colors in polarized 
light. Its appearance is represented in Fig. 4 on Pl. 12. This will make 
plain what I have said in reference to the condition of the hornblende in 
metamorphic diorites, as contrasted with the eruptive rocks. 

The triclinic feldspar appears in quite large crystals, which mostly show 
wide bands in polarized light. What species it is, one cannot say. From 
the siliceous nature of the rock, it might be supposed to be oligoclase or 
albite, and this has commonly been assumed as the fact; but in this case 
the conclusion would scarcely be justified, for the region is one of low 
metamorphism ; and under such circumstances, reasoning from the proba- 
ble conditions of chemical stability is of doubtful weight. It is enough 
to call it plagioclase. The quartz fills up the interspaces, and sits in all 
the little corners. Grains of titanic iron and bits of biotite are present. 

In a specimen of this diorite from Northumberland the feldspar is 
entirely altered into an aggregate in which epidote is prominent. Sphene 
is also quite abundant. 

A specimen from Hanover (boulder) is typical of many others. It is 


230 MINERALOGY AND LITHOLOGY. 


fine in texture, but the development of larger feldspar crystals makes it 
porphyritic. In thin sections, the hornblende is entirely of a fibrous char- 
acter; the feldspar is very impure, both as a result of decomposition and 
original inclusion of impurities. The quartz is tucked away in little cor- 
ners. In this rock the titanic iron assumes the most fantastic forms, but 
it is mostly altered into the gray product which is characteristic of all 
these diorites. This subject, however, needs no further illustration. 
Epidote, chlorite, and sphene are present in small amount. Pyrite is 
abundant. Apatite, which is so prominent in the basic eruptive rocks, 
is here but rarely seen. 

At Lancaster these rocks are abundant. Some are very dark in color 
when hornblende predominates ;, some are yellowish-green when feldspar, 
filled with epidote, predominates, and all those variations in composition 
are met with which might be expected as a result of the metamorphism 
of sedimentary beds. 


AMPHIBOLITE. 


Amphibolite is a granular massive or schistose rock, which 1s com- 
posed of amphibole with more or less quartz. Accessories, as usual, 
are present. We have the following varieties to describe: 


Amphibolite (massive hornblende rock). 
Hornblende Schist. 
Actinolite Schist. 


These rocks are very prominent among the greenstones. Their horn- 
blende possesses the same crystalline character as that of the diorites 
last described. Their relation to the diorites is shown by the frequent 
presence of triclinic feldspar. Indeed, some of the rocks rich in plagio- 
clase might be called quartz diorite if one chose to draw the line ata 
different point. This is not an unusual circumstance, for such grada- 
tions have been elsewhere observed. For example: among the so-called 
ophites of the Pyrenees there are amphibolites, which, by the gradual 
introduction of plagioclase, are stated to pass by insensible stages into 
typical diorites;—and so we have a familiar association of rocks here. 
Amphibolite. This rock is a very nearly massive aggregate of horn- 
blende crystals, or of hornblende and quartz. It occurs in the same 


LITHOLOGY. 231 


localities as the quartz diorites. Lancaster and Littleton are favorable 
places for its observation. Specimens from these places show, in thin 
sections, much hornblende, and variable amounts of quartz, and plagio- 
clase which is at times quite prominent, but is subordinate to the quartz 
in amount. Decomposing titanic iron, epidote, and sphene are present, 
and hence our amphibolites differ from the diorites only in the elimina- 
tion of the feldspar. A specimen from Northumberland is entirely com- 
posed of hornblende, with the exception of some microscopic biotite and 
pyrites. The hornblende of all these rocks is of the green fibrous variety. 
Its crystals lie at all angles and in all planes, and in this it differs from 
the schists next to be described. 

Hornblende Schist. This is a very prominent rock in the greenstone 
series. It is usually very dark in color, and is composed of deep green 
hornblende, the needles or crystals of which mostly lie in the plane of 
lamination of the rock, and considerable quartz is interspersed with it. 
This quartz is often very conspicuous in thin sections when it is scarcely 
recognizable in the mass. The hornblende, which usually is in long, 
irregular, and fibrous crystals without definite form, does sometimes, in 
the more quartzose varieties, assume the outlines natural to its crystals. 
Fig. 2 on Pl. 7 is drawn from a section of this schist from Cornish. The 
hornblende is trichroic (see p. 61), and its crystals, though possessing in 
some cases well defined prismatic planes, are always entirely lacking in 
terminal planes. This schist contains, in addition, microscopic magnetite, 
garnet, biotite, plagioclase, and epidote. The last four ingredients are not 
represented in the figure. Other specimens, in addition, contain ortho- 
clase, titanic iron, and pyrite. A variety from Stewartstown is remarkable 
for the large amount of epidote that it contains, which, though only micro- 
scopically recognizable, impresses its color on the rock. A variety from 
Hanover is celebrated for its garnet crystals, which are very perfect little 
dodecahedrons of a deep red color. Sprinkled so abundantly through the 
almost black hornblende, they make a very pretty rock. Though appar- 
ently so clear and pure, these garnets in reality are quite largely com- 
posed of quartz, as is shown by Fig. 5 on Pl. 4, which is drawn from a 
section that passes through one of them. This is a fair representation 
of the garnets as they ordinarily appear in sections of the greenstones, 
They are like crystals that form in a plastic mud, rather than in a more 


232 MINERALOGY AND LITHOLOGY. 


mobile or homogeneous mass. Many of these schists contain numerous 
biotite crystals, the bright cleavage faces of which are all parallel to the 
plane of stratification, and they dot the dark rock with black shining 
spots. Such a specimen comes from Berlin station. The crystals of bio- 
tite are sometimes very much lengthened in one direction, and then 
the rock is streaked with bright black lines. A rock of this kind occurs 
at Dummer. Some specimens are almost all hornblende, and others are 
half quartz. Some specimens are almost massive, and others are very 
schistose. Some are almost black, others are light green, and when thin 
sections are cut from this latter class they are found to contain much epi- 
dote and considerable chlorite, by which the lightness of the color is 
produced. The hornblende may vary in color and give analogous results. 
Under the microscope all these varieties present the same fibrous struc- 
ture, and no peculiarities that have not been mentioned. Hornblende 
schist is not confined to the valley of the Connecticut, but all the varie- 
ties that occur elsewhere are there to be observed. 

Actinolite Schist. This rock contains the light-colored fibrous actino- 
lite in place of the dark hornblende. It is therefore very light green; 
and in thin sections the hornblende is almost colorless. In an actinolite 
schist from Pittsburg, quartz, and some plagioclase, biotite, and chlorite, 
are included between the needles of actinolite; but the numerous crys- 
tals and needles of rutile that it contains form a striking feature. This 
mineral is present both in the quartz and in the actinolite, but its condi- 
tion is different in the two minerals. In the quartz, it exists in extremely 
fine, long black needles, which run in all directions, sometimes in straight 
lines and sometimes in curves. In the actinolite, on the contrary, it 
exists in much larger, deep yellow crystals, which are in part very well 
crystallized, and which often show the peculiar geniculations to which 
the species is subjected by its mode of twinning. A thin section of this 
rock is represented in Fig. 1 on Pl. 4. 


CHLORITE SCHIST. 


This rock is related to the argillitic mica schist that has been described, 
and is often associated with it. Intermediate varieties between the two 
rocks are abundant; and they differ only by the substitution of chlorite 


LITHOLOGY. 233 


for mica. It is therefore composed of quartz, or quartz and feldspar, 
mixed with chlorite. It is light green in its color, and does not possess 
the soft feel and glistening lustre that characterize the micaceous schists. 
It is a common rock; but though the proportion of ingredients may vary 
widely, and accessories may be present, the rock always has the same 
color and appearance. It is always fine in texture, and none of the 
ingredients are macroscopically recognizable. It is easily distinguished 
from the hornblende rocks, because, in all the amphibolites, fibrous or 
radiated crystals, which prove on examination to be hornblende, are 
always macroscopically recognizable. 

A variety of this rock from Pittsburg, when microscopically examined, 
is characterized by the presence of much plagioclase in minute grains. 
Chlorite, orthoclase, quartz, and epidote make the rest of the rock. The 
chlorite is distinctly foliated, and assumes brilliant colors in polarized 
light. Another specimen from Connecticut lake in the same town con- 
tains more quartz, less plagioclase, and much pyrites, and is otherwise 
the same. 

A variety from Diamond pond in Dixville consists mainly of chlorite 
and quartz, and contains hornblende, titanic iron, epidote, and calcite, as 
accessories. Calcareous chlorite schists are not uncommon; and when- 
ever the calcite is in grains of sufficient size to show any properties, the 
polysynthetic structure of the grains, which has been shown to be caused 
by pressure, is very conspicuous (see p. 128). 

A variety from Lebanon is dotted with black shining spots, which are 
due to magnetite that has made an effort to crystallize. Very large and 
perfect crystals of magnetite are found in chlorite schist at many locali- 
ties, though not, as I am aware of, in our state. In varieties from Lisbon 
and Raymond the chlorite is recognizable as a green, foliated mineral, 
Various sulphurets are liable to occur in chlorite schists. For example: 
about the Dalton copper mine the schists are filled with sulphurets of 
copper. 

Remarks concerning the Greenstones. I think it has been already 
plainly shown that the prevalent rocks in the valley of the Connecticut 
possess a type that separates them quite sharply from those that occupy 
the interior of the state. The interior is characterized by rocks which, 


whether massive or schistose, are highly crystalline; but the valley re- 
VOL. Iv. 30 


234 MINERALOGY AND LITHOLOGY. 


gion is just as distinctly characterized by fine-grained argillitic rocks and 
green schists, and I am going on to describe other schists and slates that 
are widely spread over this region, which have only attained a half crys- 
talline condition. Now, though quite coarse-grained crystalline rocks 
occur in this valley, still, when a rock which has the same ultimate com- 
position as a granite is found, it is usually an argillitic schist or clay 
slate. The most interesting exceptions are the coarse-grained and mas- 
sive diorites, which, on account of their condition and composition, were 
long held, and are still held by some, to be eruptive rocks. Though their 
relationships to the surrounding stratified deposits have been clearly 
pointed out by the geologists already quoted, I would point to the fol- 
lowing confirmatory circumstances, which are drawn from the litholog- 
ical study of them, and which also explain in some degree the reason for 
their massive condition. 

In the first volume of the report of this survey there is a series of maps 
prepared by Prof. Hitchcock, which indicates that the strata that form 
the interior of the state were first accumulated and elevated, and the 
valley of the Connecticut was left as a long open sea, in which the sedi- 
ments which now form these schists and greenstones were deposited. 
Therefore they were not subjected to the powerful influences, the opera- 
tion of which in the interior is shown by the highly crystalline rocks 
which are much folded, elevated into mountains, and very frequently cut 
by eruptive masses. In the valley region eruptive rocks are rare, and in 
marked contrast we see what can be accomplished by gentle metamor- 
phic action on stratified sediments; and the study of lithological spec- 
imens indicates that the following results have been produced by it. 

In the case of pure clays, but little more was accomplished than the 
consolidation and production of very minute and formless crystals. The 
same influences seem, however, to have been quite sufficient to develop 
hornblende crystals of considerable size, though the form of these crys- 
tals is imperfect. The amphibolites can therefore always be recognized 
macroscopically. Again: when triclinic feldspars appear in these rocks, 
they, too, commonly form crystals of considerable size, which are often 
well developed in an otherwise very fine mixture of minerals. If, then, 
the composition of the sediments were such as might be entirely recrys- 
tallized into triclinic feldspar and hornblende, we might expect a massive 


LITHOLOGY. 235 


and comparatively coarse-grained rock as the result of the metamor- 
phism; and as less basic strata are little modified by the same meta- 
morphism, we might expect that such massive crystalline diorites would 
appear between layers of less crystalline slates and schists. We might 
expect, also, if the composition were such as to convert the larger part 
into hornblende and triclinic feldspar, these predominant minerals would 
determine the structure, and the excess of quartz might be included 
between the crystals of a massive quartz diorite. It is well known that 
in still waters fine sediments are deposited, and that these may possess 
a very basic or a very siliceous character, as has been shown by the study 
of the composition of the materials on the bottoms of bays and harbors 
and on the ocean’s bed. Such a variety of sediments, when subjected 
to the influences that have operated on the materials of the White Moun- 
tains, would all be changed into highly crystalline rocks; but under these 
more gentle influences, only those rocks would reach a highly crystalline 
state which are composed of minerals most easily developed. The gentle 
nature of the metamorphism in these regions is indicated by the strati- 
fied, almost fragmental character of rocks of the same nature as granite, 
and the very common association of basic and acidic elements, which 
under the influence of greater heat or pressure would react on one 
another. 

Hence, as sediments of almost all varieties, from pure carbonate of 
lime on the one hand to pure sand on the other, are found at the bottom 
of still waters, it is natural that among them there will be.some deposits 
of the composition of diorites; and as diorites are easily made, then they 
may be expected at times among stratified deposits. The assumption, 
that diorites are all eruptive because the larger part of them are so, is a 
position to which exception can well be taken. 

Again: by some, rocks of this class, when plainly stratified, have been 
claimed to be the consolidated tuff or débris of basic eruptive rocks. 
Of course this may be true in some cases, yet I think that no such 
direct origin is to be attributed to these rocks which are so widely dis- 
tributed in localities all over this part of America. The question of chief 
interest is, What is the difference in microscopic structure, or other char- 
acters, between metamorphic and eruptive diorites? This question, so 
far as New Hampshire rocks are concerned, I have attempted to answer. 


236 MINERALOGY AND LITHOLOGY. 


In view of the fact that rocks of this class have been shown to be 
widely distributed over the earth, forming the strata of the Huronian 
period, Dr. Hunt suggests it as desirable that those who investigate these 
rocks should study them with the view of finding whether certain char- 
acters cannot be found to exist in them, which are so general as to serve 
as an equivalent to a determination of their age. I wish to recognize fully 
the value of such considerations, and the interest attached to the problem 
of the kind of changes that may have taken place in sediments at differ- 
ent periods of the earth’s history; but it will be noticed that the result 
of these studies has been, to lead to the conclusion that the nature of 
these rocks is simply dependent on the geographical location of the Con- 
necticut valley with reference to the surrounding land, which determined 
the nature and condition of the original sediments. The composition 
being thus fixed, their present condition is dependent on their location 
with reference to the action of the forces producing metamorphism. As 
sediments of the same nature are accumulating to-day, it therefore appears 
plain that location with reference to surroundings might produce the same 
kind of rocks in any era which is characterized by crystalline schists; 
and therefore the problem of the determination of age is thrown entirely 
upon geologists in the field, for in this case lithology can point to no rea- 
son for the maintenance of uniform conditions in different localities. To 
me, Dr. Hunt’s studies on the condition of sediments, as regards their 
permeability by water, is a more important consideration in the study of 
these rocks, for the fineness and argillitic nature of many of the strata 
are indications of impermeable sediments which would protect the solu- 
ble materials in included basic layers, and preserve in them the condi- 
tions that are necessary for the formation of the basic rocks which are 
now found among the strata. 


CLAY SLATE (ARGILLITE). 


Between argillitic mica schist and clay slate or argillite, no dividing 
line exists. Typical clay slate is a fragmental rock, which consists of 
the consolidated, nearly dehydrated material of clay beds; but the ap- 
plication of microscopic study to these slates has indicated that they do 
contain certain crystallized elements, which though very minute show 


LITHOLOGY. 237 


that something more than the mere cementation of the angular grains 
that constitute clay has taken place; and the rocks are therefore clas- 
sified as half fragmental. The amount of this crystalline product varies ; 
and when it becomes prominent, and the fragmental character is no longer 
apparent, the rock becomes argillitic mica schist. The laminated struct- 
ure has been induced in slates by pressure, and it may coincide with the 
bedding, or it may not, according to the direction in which the pressure 
was applied. This lamination is usually more regular, and is confined 
more strictly to a level plane, than is that of the other schists, and the 
ready separability of the laminz produces what is termed the slaty 
cleavage. Since this cleavage is always in a plane at right angles to 
the pressure, the direction of the pressure which produced it may be 
assumed from its plane. Therefore those argillaceous rocks in which 
the recrystallized elements are not so prominent as to impress their char- 
acter upon the rock, and which possess a slaty cleavage, are considered 
as clay slates. 

The so-called roofing slates are typical of this class, and of them a 
specimen from Littleton has been selected and examined. It is nearly 
black; and only with difficulty can a section be made sufficiently thin to 
allow of satisfactory study. It is then seen to consist of a mixture of 
quartz and feldspar in fragments as fine as dust. The mixture is rendered 
black by the inclusion of a considerable quantity of some amorphous 
coaly matters; but all through this formless mass of materials little 
needles or fibres are seen, which are brightly colored in polarized light, 
and which constitute the crystalline portion of the rock. As to the 
nature of these minute crystallites that are always found in clay slates, 
no certain conclusion has been reached. Mr. Zirkel thinks that they may 
be hornblende, and says that every careful investigation of their mode of 
arrangement points to the fact that they were formed previously to the 
consolidation of the rock. As no softening of the rock by the processes 
that have operated in the crystallization of the schists is evinced in the 
structure of the slates, this must be true; but that the needles in our 
slates are of hornblende, I doubt, for where good opportunity for examina- 
tion is found, their optical behavior is not that of inclined crystals, but 
they act much more like the fibres of mica, which in the argillitic schists 
become so much more prominent and easy to recognize. 


238 MINERALOGY AND LITHOLOGY. 


In New Hampshire, the larger part of the rocks called clay slates are 
on the boundary between clay slate and argillitic mica schist, for the 
crystalline ingredients are quite abundant. They possess in a slight 
degree a micaceous lustre, and in them a variety of minerals are devel- 
oped. For example: the clay slate from Hanover is all filled with 
minute crystals of staurolite and garnet, and such rocks are very com- 
mon in the valley region. These minerals seem to have the capacity of 
developing under influences that are insufficient to crystallize the other 
ingredients, but when cut, their sections show them to be extremely 
impure. The staurolites, under these circumstances, have not assumed 
their usual twinned forms, but are simple crystals. Some of them are 
represented in Fig. 4 on Pl. 8. 

A clay slate from Pittsburg is all covered with round spots suggestive 
of garnet. When a section of this slate is examined, these spots are seen 
to be caused by a deposit of hydrous iron oxide, which probably has re- 
sulted from the decomposition of minute grains of iron pyrites, which is 
not uncommon in these rocks. 

The Dixville notch is a good place to note the character of the scenery 
among slaty rocks, as compared with that of granitic regions. Although 
there may be exceptions enough, the granitic hills are rounded. In the 
White Mountain notch, the view, though grand in its immensity, is made 
by gently curving lines of beauty. The Dixville notch, on the other 
hand, is rude, jagged, picturesque ; for while granite wears with difficulty 
and loses its corners first, the slaty rocks, when on edge as in the Dix- 
ville notch, cleave and break down, leaving sharp points and jutting 
edges. The difference in the character of White Mountain and Alpine 
scenery is here illustrated. 


QUARTZ SCHIST. 


Quartz schist has already been referred to in the descriptions of the 
crystalline schists; but some of these rocks bear a resemblance to sand- 
stones or conglomerates, and though in part composed of crystalline 
materials, they are also in part composed of angular grains or fragments, 
and thus they form another connecting link between fragmental and 
crystalline rocks. The half fragmental character, though often visible in 
the mass, is much more satisfactorily seen in thin sections; and in Fig. 


LITHOLOGY. 239 


s on Pl. 12, a section of such a quartz schist is represented. Several 
large fragments of quartz and one of plagioclase are seen, but they are 
all surrounded by a perfectly compact mass of quartz, which without 
polarized light shows no granular structure, or any divisional lines 
which might indicate the cementation of grains, and between crossed 
Nicols it appears as usual like a complex aggregate. The large quartz 
grains have been somewhat affected, for their edges are sometimes 
indistinctly blended with the mass; and their interior structure often 
appears complex in polarized light, as if, by the influences which must 
have acted upon them, they had been altered from homogeneous grains 
into aggregates of granules. The mass of the rock around these grains 
is clearer than elsewhere, and the impurities that are contained in the 
rock bend about these fragments in something of the way that the little 
crystals in basalts are arranged around the large ones. 

With these half fragmental rocks our studies come to an end, for the 
characteristic rocks of New Hampshire are crystalline. In this connec- 
tion, the great granite breccias at the Notch and at Franconia should be 
called to mind as most wonderful examples of half fragmental rocks, in 
which, however, the fragments are so immense that they and the ground 
mass in which they are imbedded have both been considered under gran- 
ite. The slates of Mt. Pequawket, which are all cemented together by a 
paste of quartz porphyry, should also be recalled; but this rock, also, has 
been made by such an exceptional method, that it is much more instruc- 
tive to consider it among the quartz porphyries. 


FRAGMENTAL ROCKS. 


Our consolidated rocks being therefore exclusively crystalline, it will 
be profitable to consider, for comparison, a really fragmental rock. The 
Connecticut red sandstone extends up the valley from the Sound, and 
reaches the border of our state, and should receive some attention. This 
rock is often quite hard and compact; and I have filled the last space on 
the last plate with a representation of a thin section of the finest variety 
of the celebrated and beautiful Portland building stone as it appears in 
polarized light. It will be noted, then, how marked is the contrast be- 
tween a truly fragmental rock and all the rocks which have been consid- 


240 MINERALOGY AND LITHOLOGY. 


ered or illustrated. In the thin section of the sandstone are seen frag- 
ments of quartz, apparently two kinds of plagioclase, orthoclase, decom- 
posed hornblende, biotite, and magnetite. The grains of all are round 
or angular, and are packed together at hap-hazard, and the interspaces 
are empty or filled with dirt. In no case do the constituent fragments 
modify their forms to fill the spaces. All the grains are coated with red 
oxide of iron, which cements them together and determines the color 
of the rock. Further mineral constituents are also found in this same 
section, which are not represented in the figure;—for example: bits of 
microcline, decomposed muscovite, scales of hematite, and chlorite can 
be identified, and calcite, in one place, forms a part of the cementing 
material. 

In New Hampshire, all former fragmental deposits have been so 
pressed, softened, and recrystallized, that all marks of a loose open-work 
of cemented grains have been obliterated, and all the material has 
been brought into its most compact condition. The process by which 
this has been effected has been one of the prominent subjects that has 
been studied and illustrated in this work. 

All those loose deposits which constitute the glacial drift, terraces, 
gravel, sand, clay, soil, etc., are classified as fragmental rocks. These 
materials are, however, so fully discussed under the head of Surface 
Geology, by Prof. Hitchcock and Mr. Upham, that anything more than 
a reference to their chapters is unnecessary. 


MINERALS AS ROCKS. 


In order to render repetition unnecessary, anything that I had to say 
on simple rocks was included in the chapter on Mineralogy, in which 
some remarks will be found concerning limestone, soapstone, and talc 
schist, beds of various ores, the quartzite that is so abundant in veins, 
the beds of infusorial earths, and whatever other minerals in New 
Hampshire are aggregated in such amounts as to form geological 
features. The subject may therefore be dismissed at this point, for, 
though necessarily incomplete, all that has been accomplished has 


been stated. 
* * * * * * * * * 


Conclusion. In a retrospect of the course that has been followed in 


LITHOLOGY. 241 


this work, it will be noticed that a large number and a large variety of 
rocks have been classified under a small number of heads. The effort 
has been made to show that by the introduction of the microscopic 
method, many of the difficulties which have complicated the study of 
our crystalline rocks disappear, while its interest and beauty are 
increased; for not only are the compositions and present conditions 
of the rocks easily determined, but the thin sections contain a chapter 
of their histories and a record of the changes through which they 
have passed. I wish to recall again the scope of the work. It has 
not aimed to be a description of the rocks of the state, but has rather 
aimed to be a study of specimens which have been carefully selected, 
with the hope that all our important rocks would be represented 
among them. As, now, each new section that has been prepared has 
almost always presented some new features, I am certain that those 
people in the state who may be encouraged to pursue these studies 
will find in the specimens they examine, even from the very ground 
that I have traversed, as many other things of interest as have been 
here developed. New Hampshire is grand in her rocks, and it has 
been an object of this treatise to show that the beauty of them is 
not confined to those modes of arrangement which cause our state to 
be filled with the most picturesque scenery that this part of the coun- 
try has to offer, but that our rocks, in their minutest structures, are 
beautiful, and possess features which, though small, are of remarkable 
interest and of geological significance. 


VOL. IV. 31 


242 ° 


MINERALOGY AND LITHOLOGY. 


List oF FicurEs. 


PuLaTeE I. (Frontispiece.) 


A fragment of a crystal of beryl from Grafton, with a scale representing its 


Fig. 


Fig. 


Fig. 


Fig. 


Fig. 


Fig. 
Fig. 


Pa 


10. 


dimensions in feet—page 67. . 
PLATE II. 


A thin section of a rock prepared for microscopic examination; natural 
size—page 7. 

Sections of an augite crystal, drawn to illustrate the optical deport- 
ment of biaxial crystals between crossed Nicol prisms. 2a and 23, 
sections in parallel light. 2¢, a section in light rendered convergent 
by the removal of the ocular from the microscope—page 15. 

Magnetite formed by the decomposition of a hornblende crystal, as 
seen in a section of diorite from a dyke near the Profile house— 
page 43- 

Magnetite as seen in sections of diabase. 4 and 4¢@ in diabase from 
Bemis brook, 44 and 4¢ from the flume in Lincoln, 4d from Con- 
cord, Vt.—page 42. 

Product resulting from the decomposition of titanic iron, as seen in a 
section of metamorphic diorite from Connecticut lake—pages 4o 
and 228. 

The same in a section of quartz diorite from Hanover—page 41. 

Titanic iron as seen in a section of diabase from Bethlehem. 

The base of a macled crystal of staurolite from Charlestown (Jackson). 
8a the base of one of these crystals as figured by Rosenbusch— 
page Ilo. 

Figure illustrating the arrangement of the crystalline axes with refer- 
ence to one another in the plates of muscovite and biotite, which 
are frequently found united together at their edges, in the mica 
quarries—pages 80 and 83. 

Tourmaline crystals flattened out between foliz of mica—page 85. 


PLATE III. 


Crystals of arsenopyrite from Franconia (Dana); 1 and 1 @ arsenopy- 
rite; 14 danaite—page 34. 

Crystal of vesuvianite from Amherst (Dana)—page 76. 

Crystal of tourmaline from Springfield, showing the peculiar habit of 
the species as there found—page I03. 


X 30 


X 50 


x35 
x 35 
x 50 


* 
LIST OF FIGURES. 


Figs. 4and 5. Diagrams of the bases of two of the immense beryls from Graf- 
ton, giving the dimensions in inches (Hubbard)—page 67. 

Fig. 6. Crystal of cassiterite from Jackson (Teschemacher)—page 44. 

Fig. 7. A cleavage face on the green octahedral fluor spar from the Notch. 
aand é etch figures, ¢ and d cavities partially filled with water— 
page 35. 

Figs. 8and 8a. Diagrams illustrating the mode and effect of the polysynthetic 
twinning of triclinic feldspars—page 86. 

Fig. 9. Muscovite enclosing a crystal of biotite, from Alstead (Rose)—page 84. 

Fig. 10. Diagram indicating the relationship of the natural cleavage lines, which 
often divide large plates of mica, to the crystalline form, and the 
cause of this cleavage—page 84. 


PLATE IV. 


Fig. 1. Crystals of rutile in a section of actinolite schist from Pittsburg. Fine 
black acicular crystals in the quartz; larger, yellow, in part twin 
crystals in the actinolite—page 46. 

Fig. 2. Section of hypersthene in gabbro from Waterville, showing its charac- 
teristic interpositions and the method of their arrangement—page 55. 

Fig. 3. Augite crystals in a section of porphyritic diabase from Campton falls— 
page 56. 

Fig. 4. Basal section of a large crystal of beryl from Grafton, showing its en- 
closures—page 69. 

Fig. 5. A section through an apparently pure crystal of garnet, in hornblende 
schist from Hanover—page 74. 

Fig. 6. The diatoms which compose the beds of infusorial earth. Drawn by 
Ehrenberg from a New Hampshire specimen—page 52. Highly 
magnified. 


PLATE V. 


Fig. 1. Crystals of zircon in a section of the Fitzwilliam granite—page 75. 

Fig. 2. Crystals of muscovite in a section of the Roxbury granite—pages 86 
and 195. 

Fig. 3. Section through a crystal of anorthite in diabase from East Hanover, 
showing the progress of alteration—page 91. 

Fig. 4. Section of labradorite from Stark, showing two systems of polysyn- 
thetic twinning—page 93. 

Fig. 5. Section of labradorite in gabbro from Waterville, showing crystallites 
and their method of arrangement—page 94. 

Fig. 6. Triclinic feldspar interlaminated with orthoclase, as seen in a section 
of the Concord granite—pages 101 and 194. 


243 


x 30 


X 200 


x 50 


x 30 


x 200 


x 20 


X 200 


X 50 


X 30 


X 50 


x 50 


X 30 


244 


Fig. 2. 


Fig. 3. 


Fig. 4. 


Fig. 5. 


Fig. 6. 


Fig. 1. 


MINERALOGY AND LITHOLOGY. 


PLATE VI. 


Incipient alteration of andalusite, as seen in a basal section—page 106. 

Complete alteration of andalusite into cyanite, as seen in a basal sec- 
tion—page 106. 

Microscopic cavities as seen in a section of the olivine diabase from 
Campton falls. The walls are coated with sphzrosiderite, and prisms 
of calcite project into the cavities which, with this exception, are full 
of analcite—page 112. 

Apatite needles, as seen in a section of diabase from Bemis brook— 
pages 123 and 152. 

The structure of the crystalline grains which constitute ordinary lime- 
stones, as seen in thin sections between crossed Nicol prisms— 
page 128. 

Cavities common in the quartz of porphyries and granitic rocks, pages 
181 and 192,—very highly magnified. 


PLATE VII. 


Augite in a section of augite sienite from Jackson. Alteration into horn- 
blende is seen in progress, and the cleavages in the altered and unal- 
tered portions bear the same relationship to one another as do the 
prisms of augite and hornblende if constructed upon the same clino- 
diagonal—pages 57 and 206. 

Section of hornblende schist from Cornish, showing the pleochroism of 
the hornblende—pages 16 and 61. 

A crystal of hornblende in a section of eruptive diorite from near the 
Profile house. The form of the crystal is mostly filled with an aggre- 
gate of magnetite, biotite, and calcite—pages 66 and 163. 

Crystals of olivine in a section of the olivine diabase from Campton 
falls. The crystals are wholly altered into serpentine—pages 71 and 
157. 

A garnet in a section of staurolite slate, showing the progress of an al- 
teration into chlorite—page 75. 

A basal section of oligoclase from the Antrim granite. The section is 
so placed, between crossed Nicol prisms, that one set of its twin lam- 
ine is dark—page 88. 


PLATE VIII. 


Orthoclase as seen in a section of the Chocorua granite, with polarized 
light, showing the interlamination of two parts, in which the optical 
constants are differently arranged—page Ior. 


X 50 


X 50 


X 30 


x 100 


x 30 


X 30 


Xx 30 


x 30 


xX 30 


X 30 


x 30 


X 50 


Fig. 


Fig. 


Fig. 
Fig. 


Fig. 


Fig. 
Fig. 


Fig. 


Fig. 


Fig. 2 
Fig. 3 


Fig. 


Fig. 


LIST OF FIGURES. 


A basal section of microcline from the Notch, as seen between crossed 
“Nicol prisms—page 102. 

A section of fibrolite schist from the Notch, as it appears between crossed 
Nicol prisms—pages 107 and 216. 

Staurolite in a section of the staurolitic slate, as it appears with a single 
Nicol prism. The simple character and excessive impurity of the 
crystals are shown—page III. 

A section of diabase from Dixville notch. Concretions of chlorite are 
shown, which between crossed Nicols are traversed by a dark cross, 
the arms of which are parallel to the planes of the Nicol prisms— 
page 121. 

Apatite crystals in a section of gabbro from Waterville—pages 123 and 
167. 

PLATE IX. 


A section of diabase from East Hanover—page I50. 

A crystal of labradorite in a section of labradorite porphyry from Ossi- 
pee. The fractured and recemented character of the crystal, as it 
appears in polarized light, is shown—page 155. 

A crystal of augite in a section of the olivine diabase from Campton 
falls, showing a concentrically banded structure in polarized light— 
page 158. 

An altered olivine crystal, as it appears in a section of the olivine dia- 
base from Campton falls, with polarized light—page 158. 

Hornblende in a section of porphyritic diorite from Campton falls, as it 
appears with a single Nicol prism—page 161. 

Hornblende and augite associated together in a section of diorite from 
North Lisbon. The prisms are parallel. The hornblende is fresh 
and unaltered, while the augite has decayed and been removed, and 
its place has been filled by an aggregate—page 162. 


PLATE X. 


A section of gabbro from Waterville, as it appears in polarized light— 
page 167. 

A section of quartz porphyry from Mt. Lyon in ordinary light—page 179. 

The same section in polarized light, with lines indicating the directions 
in which the planes of elasticity cut the section—page 179. 

A crystal of orthoclase, which is twinned according to the Carlsbad and 
Baveno systems, in a section of the quartz porphyry from Groveton 
page 180. 

A section of a hornblende granite from Colebrook, showing the rela- 


tionship between the quartz and feldspar in regard to the order of crys- 
tallization—page 191. 


245 


x 50 


x 50 
x 30 
xX 50 
x 50 


x 50 
x 30 


x 30 
X 30 


X 30 


x 30 


X 30 
x 50 
x 50 


xX 50 


x 50 


246 MINERALOGY AND LITHOLOGY. 


Fig. 6. A section of the Troy granite, in polarized light, showing a grain of mi- 
crocline and the characteristics of the minerals which compose the 
Concord group of granites—page 195. x 50 


PLATE XI. 


Fig. 1. A section of the easily disintegrating Conway granite—page I95. X 30 
Fig. 2. A section of the Antrim granite, showing the appearance of the garnets 
which are commonly found in the granites—page 197. X 30 


Fig. 3. A section of the Mt. Carrigain granite, showing the microscopic pegma- 
tite which characterizes it—page 2o1. x 200 
Fig. 4. Centre of a mica concretion in the pudding granite from Craftsbury, 
Vt.—page 203. x6 
Fig. 5. A section of augite sienite from Jackson, showing the process of forma- 


tion of uralite—page 205. X 50 
Fig. 6. A grain of titanic iron in a section of the augite sienite from Jackson— 
page 205. x 50 
(See, also, Fig. 1 on Pl. 7, which is a section of augite sienite from another lo- 
cality.) 
PLATE XII. 


Fig. 1. A grain of quartz in a section of sienite from Columbia. The quartz is 
in contact with a crystalline grain of calcium carbonate, and encloses 
a multitude of cavities, each of which is partially filled with liquid 


carbonic acid—page 207. X 350 
Fig. 2. A section of argillitic mica schist from Woodsville—page 219. x 600 
Fig. 3. A section of metamorphic diorite from Pittsburg—page 227. xX 50 
Fig. 4. A section of metamorphic quartz diorite from North Lisbon—page 229. x 50 
Fig. 5. A section of a half fragmental quartz from Newcastle—page 239. x 30 
Fig. 6. A section of the Connecticut red sandstone—a fragmental rock—page 


239. x 30 


INDEX TO PART LV. 


Page. 

Absorption of light by eget 16 

Acidic eruptive rocks, 144 

Acidic unstratified rocks, 173 

Actinolite,: . : 60 

Actinolite schist, 232 

Age of greenstones, 236 

Albany pees 198 

Albite, 98 

Almandite, . 72 

Alteration of basic eruptive rocks, 149 

Alum, ‘ 3 . ‘ 126 

Amazon stone, 102 

Amethyst, ‘ 49 
Amorphous bod bodies, optical properties 

co) : - 10 

Amphibole, 60 

Amphibolite, 230 

Analcite, . 112 

Analysis of albite, 98 

andesite, 96 

$s anorthite, ‘ gI 

ee anorthite diabase, . 156 

a argillitic mica schist, 219 

ee beryl, : 69 

ae biotite, . 79 

ss chalcopyrite, . 33 

as chlorophyllite, 78 

ie chrysolite, 70 

es columbite, 122 

as danaite, 34 

ee diabantite, : 120 

as diorite—eruptive, . 161 

sé diorite—metamorphic, . 228 

“ galenite, . 28 

ie garnet, 73 

es hematite, . - 38 

es hornblende, . - 63, 64, 65 

ss infusorial earth, a bz 

# iolite, i Oe 

es labradorite, 93, 95 

ei magnetite, »  4l 

ee micaceous diabase, 153 

as mountain cork, 115 


VOL. Iv. 32 


Analysis of olivine, . 


te orthoclase, 

oi pargasite, 

we prochlorite, 

us pyroxene, . 
ae quartz porphyry, 
es sphalerite, 

ee staurolite, 

es tourmaline, 

es triphylite, 

ne zircon, 

Andalusite, ‘ : ‘ 
fs alteration to cyanite, 
ee mica schist, 

Andesite, : ‘ 

Andradite, : a 

Ankerite, a 

Annite, 

Anorthite, 

Anorthite diabase, 

Anthophyllite, 

Antrim granite, 

Apatite, : 

Argentiferous galena, . 

Argentine, . 

Argentite, 2 

Argillite, . c 


Argillitic mica schist, 

Arsenic (native), 

Arsenopyrite, . 

Asbestus, 

Augen gneiss, . 

Augite, 

oe associated with hornblende, 

‘© in quartz porphyry, 
optical properties of 

“© sienite, : 

Autunite, 

Azurite, 


“ce 


Barite, 
Basic diorite, 


248 INDEX TO 
Page. 
Basic eruptive rocks, 144 
Baveno twins, . - 99 
ae in quartz porphyry, - 180. 
- 66 


ve 


hes microscopic inclusions in 69 
Bethlehem gneiss, . 214 
Biotite, 79 

«gneiss, 213 
‘* granite, 195 


‘« associated with muscovite, 80, 83 


«¢ muscovite gneiss, 213 
Black argillitic schist, 220 
Blende, 29 
Bog-iron ore, . 46 
Bornite, . 29 
Boulders at Gilford, 169 

“at Thetford hill, 157 

‘© of gabbro, . 169 
a of labradorite at Stark, 169 


Breccia cemented by a porphyry, 184 
‘* granite, . + 197 


“« — of schist, 221 
«« of slate, 222 
Broken crystals of labradorite, 155 
a strata, a ¢ 221 
Brown tourmaline, . 103 


Brush, Prof. Geo. J., services of . 5 
Bubbles in rock cavities, . fs Bees 193 


Buhrstone, 50 
Bunsen’s division of eruptive rocks, 144 
Cadmium in zinc blende, 30 
Calcite, . 5 127 
Carbonic acid in rock cavities, 207 
Carlsbad twins, : 99 
Cassiterite, 44 
Catalogue of mineral localities, 132 
Cavities in acidic rocks, . 181, 192 
ce fluorite, . 37 

te minerals, j é ‘ 9 
Chalcocite, F : 30 
Chalcopyrite, . . 32 
Chalybeate springs, 37 
Chiastolite, . gj 106 
Chiastolite schist, 220 
Chlorite, . 117, 58 
ss schist. 232 
Chloritic diabase, . 150 
Chlorophyllite, 78 
Chocorua granite, 200 
Chromite, 44 
Chrysoberyl, 44 
Chrysolite, 70 
Cinnamon garnet, 73 
Circular polarization, - 18 


Classification of basic eruptive ‘rocks, 148 


ee rocks, 141 
Clay, s F II4 
Clay slate, 236 
Claystone porphyry, 185 


PART Iv. 


Page, 
Cleavage of minerals in sections, 10 
Cleavages in mica, . 80 
Colebrook granite, . 198 
Columbite, 121 
Concord granite, 194 
ae meteorite, . 24 
Concretionary granite, 203 
Concretions of chlorite, : 4 “E21 
Connecticut sandstones, . . » 239 
Contact metamorphism, . ‘ « 3282 
Conway granite, 195 
Copper, 23 
‘*  pyrites, 32 
‘© schist, 220 
Corundum, . : a 5 - 38 
Crystallites, . . 3 : : 9 
ts in clay slates, ‘ - 237 
fe in labradorite, 94 
Cyanite, . 108 
Danaite, : ‘ 34 
Dartmouth college, é 19 
Decay of basic rocks, 172 
ee rocks, 140 
Delessite, 120 
Diabantite, 120 
Diabase, . 149 
Diallage, 165 
Diatoms, P Bz 
Diorite (eruptive) : 159 
‘¢ (metamorphic), . 225 
‘© origin of 160 
Disintegrating granite, 195 
Diversity in eruptive rocks, 170 
es New Hampshire erup- 
tive rock, Fi « 1 
Dixville notch, 238 
Dolomite, 130 
Eaten apatite crystals, 168 
Endogenous granite, 189 
Epidote, . : ‘ 76 
Etch figures on fluorite, ‘ 35 
Exotic granite, 189 
Fahlunite, 78 
Feldspar, 86 
Felsite, 175 
Fetid limestone, 129 
Fibrolite, é 107 
ae mica schist, 216 
Field work upon rocks, 14 
Fitzwilliam granite, 194 
Flattened fossils, 221 
ce minerals in mica, 85 
oe pebbles in schist, . 220 
Fluidal enclosures in rocks, 181, 192 
Flumes, . : - - 147 


INDEX TO PART IV. 


Fluorite, - 
se in granite, 
Formation of metamorphic diorites, 
Fossiliferous limestone, . 
Fossils, flattening and distortion of. 
Fragmental rocks, , 
Franconia granite, . 
Gabbro, . 
«altered 5 
“© relation to diabage, 158, 
Galenite, . ; , ‘ 
Garnet, . 
ee altering to chlorite, : 
a impurities in # . 
Garnetiferous mica schist, 
Gneiss, és 
Gold, ‘i 
Granite, . 5 . : 
ee classification of . F , 
te veins, : . : . 
Granitell, 
Granitic gravel, : 
ee porphyries, , 
v6 rocks, f a ; ‘ 
Graphic granite, . : . 201, 
Graphite, ‘ ‘ ¢ - ‘ 
Greenstones, . . Zz ‘ 
es age of , ‘ r 
Green vitriol, . ‘ 
Haverhill granite, , 
Hematite, : 
Hemithrene, . 
Hexagonal crystals, optical proper- 
ties of . 
Hollow crystals i in diorite, 
Hornblende, ‘ F 
ee alteration of . 66, 
ee associated with augite, 
[x7 ce 
ss biotite gneiss, 
ee granite, 
ie pleochroism of 
ce schist, 


sienite, : 
Hubbard, Prof. O. P., researches of 
Hunt, Dr. T. S., researches of 
Hydro-mica slate, 

Hydrous silicates, 

Hypersthene, . 


Idocrase, 

Impurities in minerals, 
Indicolite, e 
Indigenous granite, 
Infusorial earth, 

lolite, 


VOL. IV. 32 


Page. 
Iron (native), - 23 
‘« pyrites, . at 
Isometric crystals, optical properties 
of : : = aE 
Jackson, Dr.C. F., geological report 
of ¥ é 2 : - 19 
Jasper, . 5o 
Kalinite, r E ‘ . 126 
Kaolin, . ‘ Z x ‘ . 14 
Labradorite, - : . . 92 
s boulders at Stark, 169 
es porphyry, 154 
Lepidomelane, : : 81 
Limestone, . : 127 
Limits of rock species, a - 140 
Limonite, - 46 
Liquid carbonic acid in rocks, . : + 207 
List of minerals found in New Hamp- 
shire, . 20 
List of rocks found in New Hamp- 
shire, . : é - 143 
Lithia in biotite, z 81 
Lodestones, : . z 42 
Lyman schist, . : 5 . 218 
Macles of staurolite, 109, 220 
Magnetic pyrites, 30 
Magnetite, 41 
Hs as decomposition product, 43 
as in diabase, 42 
Malachite, 131 
Marble, 128 
Marcasite, 32 
Marceline, 59 
Margarodite, ‘ 116 
Marlborough granite, eT 
Massive debace, a 
Measurement of crystals i in sections, 9 
Melaconite, " 37 
Melanterite, 126 
Menaccanite, . . 39 
Mesozoic eruptive rocks, . 146 
Metamorphic diorite, + 225, 234 
Meteorite, yf ‘ . 24 
Mica, . 78 
Micaceous diabase, . : . 152 
s quartz schist, + 223 
Mica diorite, + 165 
** hornblende granite, . 198 
‘« schist, at 
Microcline ce 
: 102 
Microlites, 
Microscope for examination of min- 
erals, ‘ 4 ? 8 


250 


Mineral localities, 
Minerals as rocks, 
Mineral springs, 
Mispickel, 
Molybdenite, . 
Molybdite, 
Monoclinic crystals, optical properties 
of ‘ 
Mountain. cork, 
‘ leather, 
ei meal, 
Motion of bubbles i in rock cavities, . _ 
Mount Carrigain granite, 


Muscovite, . . 
ee biotite granite, 
ee gneiss, . 
66 granite, 


Novaculite, : A é ‘ 


Oil stone, : 

Old eruptive rocks, . 

Oligoclase, 

Olive-green granites, 

Olivine, . 

Olivine, decomposition of 

Olivine diabase, ‘ 

Opal, : 

Optical properties of minerals in sec- 
tions, . 

Optical properties, tabular arrange- 
ment of : : 2 

Origin of rock species, 

Orthoclase, 

Orthoclase and albite interlaminated, 

Orthoclase porphyry, 

Orthorhombic apes optical Prop: 
erties of 

Ossipee granite, 

Outlines of crystals in sections, 


Palatinite, 
Paragonite, 
Pargasite, 
Pebbles flattened between n layers of 
schist, : 
Pegmatite, 
es microscopic 
Pegmatitic granite, 
Penninite, " 
Phyllite, . 
Pinite, 
Plagioclase, “ 
es diorite, . ‘ 
Pleochroism of crystals, . 
Polishing powder, 
Porphyries, P : 
ue classification of 


164, 


222 


INDEX TO PART IV. 


Porphyries, diversity of . 

ee origin of 
Porphyritic diabase, 

ge diorite, . 

as felsite, . 
Porphyrite, 
Porphyry breccia, ‘ 

‘* conglomerate, . 
Portland sandstone, 
Prehnite, ‘ 
Pressure cleavage i in mica, 
Pressure under which granites crys- 
tallized, 183, 

Primal rocks, , c y 
Prochlorite, 
Protogene, 

ne gneiss, 
Pudding granite, 
Purple copper, a 
Pseudo-porphyritic granite 
Psilomelane, 
Pyrite, 
Pyroxene, ‘ 
Eocene and hornblende, relations 

of, ‘ 

Pyroxene crystals i in rock sections, | 
Pyrolusite, , 
Pyrrhotite, 


Quartz, 
us diorite, : 
Quartz-free acag porphyry, 
Quartzite, 
Quartz porphyry, 
“*« schist, 
‘© schist, half fragmental, 
‘* veins, . 


Red diorite, 

‘granite, 

“« sandstone, 
Remarks on basic eruptive rocks, 

i on greenstones, 
Rhodochrosite, zi 
Rhodonite, 
Ripidolite, 
Rock analysis, 
es methods of 

Roofing slate, : 
Rose quartz, 
Roxbury ane 
Rutile, . 


Salts in solution, in rock cavities, 


181, nes 192, 202 


Saussurite, 92 
Scenery among slaty rocks, 238 
Schistose, structure- causes of 210, 212 


INDEX TO PART IV. 


Scorodite, 
Sericite, . 
Serpentine, 
Siderite, . 
Sienite, 
Silver, F 
‘mines, . 
Silesian gabbros, 
Slate, 
Slaty cleavage, 
Smoky quartz, 
Soapstone, . 
Softening of pebbles in ‘fragmental 
rocks, . F ‘ . . i 
Spessartite, r . : F 
Sphaerosiderite, . ‘ i ‘ 
Sphalerite, - 
Sphene, . 
Spinel, 
Spodumene, 
Staurolite, . 2 
es mica schist, 
Steatite, . é 
Stibnite, 
Stinkstone, 
Stratification of gneiss, 
Strike figures on mica, 
Structural ae in eruptive 
rocks, : : 3 
Sulphur (native), 
Sulphur springs, 
Sunapee granite, 
Surface deposits, 
Syenite, see Sienite. 


Talc, z 
1 ae at which granites crys- 
ze 
Tetragonal crystals, optical proper- 
ties of ‘ 
Tetrahedrite, . 


Page. 


Thin sections, examination of 
es preparation of . 
Tin stone, e ‘ 
Titanic iron, 
Titanic iron, decomposition of. 
Titanium in iron ores, 
Titanite, ; 
Tourmaline, 
Tourmalines in mica, 
Tourmaline in quartz, 
Trachyte, . 
Tremolite, 
Triclinic crystals, optical properties of 
Triphylite, 
Tripolite, 
Troy granite, . : . : 
Twinning of feldspars, ‘ 5 ‘ 


Uralite, 
Uranium in molybdite, 
Urthonschiefer, 


57> 


Variegated copper ore, 
Veinstones, granitic 
Vesuvianite, 

Viridite, . 


Wad, 

Water, 

Wavellite, 

Wavy gneiss, . : 
Whitefield granite, - 
White iron pyrites, . 
Wolframite, 5 


Young eruptive rocks, 


Zinc blende, 
Zircon, 
Zoisite, 


16 
124 


APPENDIX. 


CATALOGUE OF A SELECT COLLECTION OF NEW HAMPSHIRE 
ROCKS. 


This is a catalogue of a series of specimens which have been gathered by the geolog- 
ical survey, with the idea in view of representing in a limited collection the typical rocks 
of the state. Prof. Hitchcock has placed such a series at the state house, at Dartmouth 
college, the normal school at Plymouth, and elsewhere. The special collection, which 
has furnished the material for the studies detailed in this book, has embraced the rocks 
mentioned in this catalogue, though in order to render the work more complete a large 
number of additional specimens, collected by the writer and others, has been consid- 
ered. This collection at present is preserved in the Peabody museum of Yale college ; 
and for this collection alone the writer is responsible. The references are to the pages 
where the specimens have been particularly described. 


1. Diabase, East Hanover, p. 150. 

. Diabase, Mt. Washington river, p. 151. 

. Diabase (loose), Rye, p. 152. 

. Diabase, Bartlett. 

. Mica diabase, Flume, Lincoln, p. 153. 

. Mica diabase, Wakefield (not Dixville), p. 153. 
. Mica diabase, Waterville. 

. Labradorite porphyry, Ossipee, p. 154. 


Oo ON Aw FW N 


, Anorthite diabase, East Hanover, p. 155. 

Io. Anorthite diabase, Concord, Vt. 

11. Olivine diabase, Campton falls, p. 157. 

12. Diorite (porphyritic), Campton falls, p. 161. 

13. Diorite (porphyritic), Campton falls, p. 162. 

14. Diorite (porphyritic), North Lisbon, p. 162. 

15. Diorite (porphyritic), Profile house, Franconia, Pp. 163. 
16, Diorite (porphyritic), Dixville notch, p. 164. 


256 APPENDIX TO PART IV. 


17. 
18. 
19. 
20. 
21; 
22), 
23. 
24. 
25 
26. 
27. 
28. 
29. 
30. 
31. 
32. 
33- 
34- 
35- 
36. 
37- 
38. 
39- 
4o. 


4l. 


42. 
43. 
44. 
45. 
46. 
47. 
48. 
49. 
50. 
5I. 
52; 
53- 
54. 
55. 
56. 


Diorite (porphyritic calcareous), Dixville notch, p. 164. 

Mica diorite (calcareous), Stewartstown, p. 165. 

Gabbro, Waterville, p. 166. 

Gabbro, Mt. Washington river, p. 168. 

Gabbro, Gilford, p. 169. 

Gabbro (decomposed), Waterville, p. 168. 

Labradorite (loose), Stark. 

Felsite, Mt. Washington river, p. 175. 

Felsite, Bemis brook, p. 176. 

Black quartz porphyry, North-east Waterville, p. 178. 

Black quartz porphyry, Albany. 

Black quartz porphyry, Mt. Lafayette. 

Gray quartz porphyry (little quartz), Groveton, 180. 

Red quartz porphyry, Pemigewasset, p. 185. 

Red quartz porphyry, Albany, p. 185. 

Red quartz porphyry, Waterville, p. 185. 

Quartz porphyry (granitic), Waterville, p. 185. 

Quartz porphyry (white), Dorchester. 

Quartz porphyry, Waterville. 

Porphyry conglomerate, Waterville, p. 186. 

Porphyry conglomerate, Albany, p. 186. 

Quartz porphyry, Twin mountain. 

Quartz porphyry (claystone porphyry), Mt. Willard, south side, p. 185. 

A breccia of argillitic schist formed by the eruption of quartz porphyry, Mt. Pe- 

quawket, p. 184. 

A breccia composed of a mixture of argillitic schist and quartz porphyry, Mt. Pe- 
quawket. 

Quartz porphyry, including clay state, Mt. Willard. 

Quartz porphyry (granitic), Mt. Pequawket, p. 188. 

Quartz porphyry, Mt. Pequawket, p. 184. 

Muscovite granite (garnetiferous), Barrington. 

Muscovite biotite granite, Concord, p. 194. 

Muscovite biotite granite, Fitzwilliam, p. 194. 

Muscovite biotite granite, Marlborough, p. 195. 

Muscovite biotite granite, Troy, p. 195. 

Muscovite biotite granite, Manchester, p. 195. 

Muscovite biotite granite (little muscovite—dark), Plymouth, p. 195. 

Muscovite biotite granite, Hooksett, p. 195. 

Muscovite biotite granite, Sunapee, p. 195. 

Muscovite biotite granite, Farmington. 

Muscovite biotite granite, Essex county, Vt. 

Muscovite biotite granite, Effingham, p. 195. 


APPENDIX TO PART IV. 257 


. Muscovite biotite granite, Haverhill, p. 195. 

. Muscovite biotite granite, Elephant’s Head. 

. Muscovite biotite granite (coarser), Concord. 

. Muscovite biotite granite (coarser), Fabyan’s. 

. Muscovite biotite granite, Dixville. 

. Biotite granite (disintegrating granite), Conway, p. 195. 

. Biotite granite, Mt. Willard. 

. Biotite granite (loose), Crawford house. 

. Biotite granite (pink), Lincoln, p. 197. 

. Biotite granite (pink), Moose mountain, New Durham. 

. Biotite granite (red), Stratford, p. 197. 

. Biotite granite, Stark, p. 197. 

. Biotite granite (pseudo-porphyritic), White house, Mt. Kearsarge. 
. Biotite granite, Mission Ridge, Mt. Kearsarge. 

. Biotite granite (contains some hornblende), Newmarket. 

. Biotite granite, White Mountain Notch, p. 197. This granite cements together 


angular fragments of gneiss. 


. Biotite granite, White Mountain Notch, p. 197. This granite cements together 


angular fragments of gneiss. 


. Gneiss included in the above granite, forming a great breccid, p. 197. 
. Gneiss, which is included in a granite forming a great breccia, Franconia, p. 197. 
. Mica hornblende granite (olive green), Stratford, p. 198. 

- Mica hornblende granite (olive green), Bartlett, p. 199. 

. Mica hornblende granite, Frankenstein cliff, p. 199. 

. Mica hornblende granite (Albany granite,) Jackson, p. 199. 

. Mica hornblende granite, Ossipee. 

. Mica hornblende granite, Waterville. 

- Mica hornblende granite (red), Goodrich falls, Bartlett. 

. Granite with muscovite and white hornblende, Bemis saw-mill. 

. Hornblende granite (Albany granite), New Zealand brook. 

- Hornblende granite, Stark, p. zor. 

. Hornblende granite (red), Bartlett. 

- Hornblende granite (Albany granite), Albany. 

- Hornblende granite (Albany granite), Bemis. 

. Hornblende granite (microscopic pegmatite), Mt. Carrigain, p. 201. 
- Hornblende granite, Stark. 

- Hornblende granite (red), Waterville. 

. Granitell, Mt. Ascutney, Vt., p. 202. 

. Feldspar from bed, Newcastle. 

. Augite sienite (uralitic), Jackson, Pp. 205. 

- Hornblende sienite, Red hill, Moultonborough, p. 206. 

. Hornblende sienite, Columbia. 


VOL, Iv. 32 


258 APPENDIX TO PART IV. 


97. Hornblende sienite, Stark. 
98. Hornblende sienite (very fine grained), Albany. 
99. Muscovite gneiss (garnetiferous), Hinsdale (not Chesterfield), p. 212. 
100. Muscovite gneiss, Nashua. 
1o1. Biotite gneiss, Holderness, p. 213. 
102. Biotite gneiss (quarried), Enfield, p. 213. 
103. Biotite gneiss (little feldspar), Whitefield, p. 213. 
104. Biotite gneiss (opalescent quartz), Bradford, Vt. 
105. Biotite gneiss (pseudo-porphyritic), Waterville, p. 213. 
106. Biotite gneiss (pseudo-porphyritic), Franconia, p. 213. 
107. Biotite muscovite gneiss (pseudo-porphyritic), Newbury, p. 213. 
108. Biotite muscovite gneiss (pseudo-porphyritic), Meredith Village. 
10g. Biotite muscovite gneiss (pseudo-porphyritic), Bethlehem, p. 213. 
110. Biotite muscovite gneiss (almost mica schist), Newport, p: 214. 
111. Biotite muscovite gneiss (little mica), Bethlehem, p. 214. 
112. Biotite muscovite gneiss, Hanover, p. 214." 
113. Biotite muscovite gneiss, Whitefield, p. 214. 
114. Biotite muscovite gneiss, East pond, Wakefield, p. 214. 
115. Biotite muscovite gneiss (garnetiferous), Marlow, ‘p. 214. 
116. Biotite muscovite gneiss (granitic gneiss), north-west from Crawford house. 
117. Biotite muscovite gneiss, Ossipee. 
118. Biotite muscovite gneiss, Wakefield Corner. 
119. Biotite muscovite gneiss, Carroll, p. 214... -- 
120. Biotite muscovite gneiss (almost mica schist), Wentworth. 
121. Biotite muscovite gneiss, Randolph. 
122. Biotite muscovite gneiss, Salem. 
123. Biotite gneiss (decayed mica—pyrrhotite), White Mountain Notch. 
124. Biotite oligoclase gneiss, ‘‘ Westport granite,” Swanzey, p. 213. 
125. Biotite hornblende gneiss, Mt. Franklin, Swanzey, p. 214. 
126. Biotite hornblende gneiss, Littleton, p. 215. 
127. Biotite hornblende gneiss, Wolfeborough. 
128. Protogene gneiss, Littleton, pp. 202 and 215. 
129. Protogene gneiss (pseudo-porphyritic), Lancaster, pp. 202 and 215. 
130. Protogene gneiss, Groveton, pp. 202 and 21 5. 
131. Protogene gneiss (epidotic), Walling’s quarry, Lebanon, p. 202. 
132. Protogene gneiss, Lyman. 
133. Protogene gneiss (red), Surry summit. 
134. Mica schist, Mt. Pequawket. 
135. Mica schist, Troy, p. 215. 
136. Mica schist, Acworth centre, p. 215. 
137. Mica schist, Amoskeag quarry, Manchester (not Bedford), p. 216. 
138. Mica schist, Bemis. 


139. 
140. 
14. 
142. 
143. 
144. 
145. 
146. 
147. 
148. 
149. 
150. 
ISI. 
152. 
153- 
154. 
155: 
156. 
ce 
158. 
159. 
160. 
161. 
162. 
163. 
164. 
165. 
166. 
167. 
168. 
169. 
170. 
171. 
172. 
173. 
174. 
175. 
176. 
177. 


178. 


APPENDIX TO PART IV. 259 


Mica schist (garnetiferous), Wakefield. 

Mica schist, Epping. z 2 

Mica schist (nearly massive), White Mountain Notch. 

Mica schist, Orford. 

Mica schist, Stark water-station. 

Mica schist, Jackson falls. % 

Mica schist, top of Mt. Washington. 

Mica schist (massive), Mt. Washington carriage-road. 

Mica schist, Littleton. 

Mica schist (whetstone schist), Piermont. 

Mica schist (ferruginous), Ashland. - 

Mica schist, Colebrook. 

Mica schist, Groveton. 

Mica schist (fine grained), North Lisbon. 

Mica schist (argillitic), Groveton. 

Mica schist, Lyndeborough. _ 

Mica schist (calcareous), Colebrook. 

Andalusite mica schist, Mt. Willard, p. 216. 

Andalusite mica schist, Mt. Washington. 

Chiastolite mica schist, Mt. Washington carriage-road. 

Fibrolite mica schist, Rumney. 

Fibrolite mica schist, top of Mt. Washington, p. 217. 

Staurolite mica schist, Enfield, p. 217. 

Staurolite mica schist, Charlestown, pp. I10 and 217. 

Garnetiferous mica schist, top of Mt. Monadnock, p. 217. 

Argillitic mica schist, Woodsville, p. 218. 

Argillitic mica schist, Wells River, Vt., p. 218. 

Argillitic mica schist, Stark, p. 218. 

Argillitic mica schist, Lisbon, p. 218. 

Argillitic mica schist (containing copper pyrites), Lyman, p. 220. 

Argillitic mica schist (black, siliceous), Dalton, p. 220. 

Argillitic mica schist, Dalton copper mine. 

Argillitic mica schist, Piper hill, Stewartstown. 

Argillitic mica schist, Stewartstown. 

Argillitic mica schist, Chesterfield. 

Argillitic mica schist, Lyman. 

Argillitic mica schist, Portsmouth. 

Argillitic mica schist, with flattened pebbles, Hanover, p. 220. 

Argillitic mica schist, with staurolite and garnet crystals, Bernardston, Mass., 
p. 238. 

Argillitic mica schist, with staurolite and garnet crystals, Bernardston, Mass., 
p. 238. 


260 APPENDIX TO PART IV. 


179. Argillitic mica schist (garnetiferous), Hanover, p. 238. 
180. Argillitic mica schist (garnetiferous), Lyme. 
181. Argillitic mica schist, East Lebanon. 

182. Argillitic mica schist, Lyman. 

183. Argillitic mica schist, Dixville notch. 

184. Novaculite (gray), Littleton, p. 222. 

185. Novaculite (black), Tamworth, p. 222. 

186. Quartz schist, Hinsdale, p. 223. 

187. Quartz schist, Charlestown, p. 223. 

188. Quartz schist, Chesterfield, p. 223. 

189. Quartz schist (micaceous), Littleton, p. 223. 
190. Quartz schist, Piermont, p. 223. 

191. Quartz schist, Orford, p. 223. 

192. Quartz schist, Bernardston, Mass., p. 223. 
193. Quartz schist, Winchester, p. 223. 

194. Quartz schist, Hinsdale, p. 223. 

195. Quartz schist (micaceous), Lisbon p. 223. 
196. Quartz schist, Surry, p. 223. 

197. Quartz schist, Lancaster, p. 223. 

198. Quartz schist (pyritiferous), Dalton, p. 223. 
199. Quartz schist (pyritiferous), Lyman, p. 223. 
200. Quartz schist, Hanover, p. 223. 

201. Quartz schist (whetstone schist), Connecticut lake, p. 223. 
202. Quartz schist (chloritic), Lyman, p. 223. 
203. Quartz schist, Winchester, p. 223. 

204. Black quartz schist, Newcastle. 

205. Quartz schist (half fragmental), Littleton. 
206. Quartzite, Surry, p. 80. 

207. Quartzite, Raymond, p. 80. 

208. Quartzite, Amherst, p. 50. 

209. Quartzite (buhrstone) Littleton, p. 50. 

210. Quartzite (calcareous), Jackson. 

211. Metamorphic.diorite, Littleton, p. 228. 

212. Metamorphic diorite, Pittsburg, p. 227. 
213.’ Metamorphic diorite, Cornish. 

214. Metamorphic quartz diorite, Hanover. 

215. Amphibolite (containing triclinic feldspars), North Lisbon, p. 229. 
216. Amphibolite, Littleton, p. 230. 

217. Hornblende schist, Cornish, p. 231. 

218. Hornblende schist, Winchester. 

219. Hornblende schist (black), Surry"summit. 
220. Hornblende schist (black), Fitzwilliam. 


221. 
222. 
223. 
224. 
225. 
226. 
227. 
228. 
229. 
230. 
231. 
232. 
233. 
234. 
235. 
236. 
237. 
238. 
239. 
240. 
241, 
242. 
243. 
244. 
245. 
246. 
247. 
248. 
249. 
250. 


APPENDIX TO PART IV, 261 


Hornblende schist, Piermont. 

Hornblende schist, Stark. 

Hornblende schist, Westmoreland. 

Hornblende schist (epidotic, chloritic), Milan, p. 232. 
Hornblende schist (garnetiferous), Hanover, pp. 74 and 231. 
Hornblende schist, Hanover, p. 232. 

Chloritic quartz schist, Lebanon, p. 233. 

Chlorite schist, Connecticut lake, p. 233. 

Chlorite schist, Lisbon, p. 233. 

Chloritic mica schist, Raymond, p. 233. 

Chlorite schist, North Lisbon, p. 233. 

Chlorite schist, Dalton, p. 233. 

Clay slate (roofing slate), Littleton, p. 237. 
Conglomerate, North Lisbon. 

Conglomerate, North Lisbon. 

Auriferous conglomerate, Lyman. 

Quartzite (veinstone), Madison lead mine, p. 80. 
Quartzite (veinstone), Cornish, p. 80. 

Quartzite (veinstone—auriferous), Dodge mine, Lyman, p. 50. 
Soapstone, Francestown. 

Soapstone, Lancaster. 

Soapstone (talc schist), Orford. 

Soapstone (talc schist), Orford. 

Limestone (micaceous), Haverhill. 

Limestone (white, Helderberg), North Lisbon. 
Limestone (gray, Helderberg), Littleton. 

Limestone (crinoidal, Helderberg), Bernardston, Mass. 
Siliceous limestone, Cornish. 

Dolomitic limestone (very siliceous), Lyman. 
Magnetite, Franconia. 


ARRANGEMENT BY FORMATIONS. 


For the convenience of those who wish to study the rocks in their stratigraphical 


relations, Prof. Hitchcock adds the following numbers, to correspond with the classifi- 


cation of the formations in Volume II, beginning with the lowest one: 


Pains have been taken to have all the specimens exactly alike, so that those who 


obtain duplicate collections, by purchase or otherwise, may be sure that Mr. Hawes’s 


accurate descriptions in the chapter on Lithology are applicable to their set. A. A. 
Julien, of the School of Mines at Columbia college, New York, has for sale, prepared 


262 APPENDIX TO PART IV. 


at our request, thirty microscopic sections cut from the following numbers: 1, 3, 6, 8, 
10-12, 14, 16, 19-21, 23, 26, 29, 32, 44, 46, 49, 57, 62, 76, 79, 83, 128, 94, 96-98, 107, 
126, 139, 164, 178, 179, 212, 217, 225, 240. Many of them have been figured in our 
plates, and are further explained in a descriptive commentary accompanying the slides 
and specimens purchased. 


Porphyritic Gneiss. To this belong Nos. 105-109, and 149. It has been cut by 
Nos. 7 and 14. 

Bethlehem Gueiss. Nos. 102, 103, L11, 112, 113, 119, 124, 126, 133, 196, 244, 218, 
220. ‘ 

Lake Winnipiseogee Gneiss. Nos. 50, 52, 53, 101, 110, 117, 118, 120, 121, 122, 
125, 127, 137, 206, 208, 250. It has been cut, probably, by No. 8. 

Montalban Group. Nos. 46-49, 51, 54, 55, 58-60, 114, 116, 123, 135, 139, 138, 145, 
159, 160, 210, 237. 

The following intrusive rocks have cut this formation: Nos. 2, 6, 11-13, 19, 20, 22, 
and 24. 

Franconia Breccia. Nos. 74 and 75, with Nos. 72 and 73 for cement, cut by No. 15. 

Huronian (Hornblende schist). Nos. 217, 219, 221-226. 

Lisbon Group. Nos. 104, 128, 130, 132, 150, 151, 153, 184, 201, 211-216, 228-231, 
241 ;—cut by No. Io. 

Lyman Group. Nos. 143, 144, 164-166, 168, 174, 183, 197-199, 242, 249 ;—Ccut by 
Nos. 16, 17, 18. Swift Water series, 167; auriferous conglomerate, 236. 

Merrimack Group. Nos. 140, 204, 175. 

Ferruginous Slate Group. No. 240. 

Rockingham Group. Nos. 154, 45, 207. 

Kearsarge Andalusite Group. Nos. 134, 141, 146, 156-158, 163. 

Cambrian Slates. Nos. 99, 169-171, 173, 181, 182, 232, 234, 235, 239. 

Cois Group (Quartzite of Vol. II). Nos. 186-188, 190-193, 200, 203. 

Mica Schist and Staurolite Rocks. Nos. 136, 142, 147, 148, 161, 162, 172, 177, 
178, 180, 189, 227, 243, 238 ;—cut by Nos. 1 and 9. 

Calciferous Mica Schist. Nos. 155 and 248. 

Helderberg. Nos. 152, 176, 205, 209, 245-247. 

To Conway granite are referred Nos. 62-65, 67, 81, 82, 86;—cut by Nos. 4, 5, 25. 

Albany Granite. Nos. 39, 79, 86, 87, 88. 

Chocorua Granite. Nos. 76-78, 80, go. 

Exeter Sienite. No. 71; other sienites, Nos. 95, 96, 85, 97. 

Pequawket Breccia. Nos. 40-44. Granite cutting Cods group, No. 57. 


PART IV PLATE I. 


1 


Diabase 
|| E. Hanover NH. 


Augite Chlorite 
uelite Epidote 
Biotite Apatite. 


=W_ Hawes, del are shu ar 
= W Haw Sree E.Untsand, lith New Haven. 


PART IV. PLATE I. 


40 


Naturalpressure cleavage Ss 


i 
/ On 
y | a 
a oe 5 
{ i e I / | 
| (erp 
' £ / § vax } 
: / | ¥° Wipe | 
\ a ( Cleavage e Cleavage 
a i \ induced by L- =g5 wnduced by 
7 - } a blow pressure 4 
d | 


E.Crisand, lith New Haven. 


GW. Hawes, del 


PLATE IV. 


fp 


ae LELERE IR 


sand, lith New Haven. 


E.¢n 


el 


W. Hawes de 


V 


ica & 
is ie 
E 2 
a 
=) = 
Ay = 
< 

oO 

g 

3 

fr] 


o 
a=] 
a 
® 
& 
iss] 
pst 
= 
x) 


ae 


PART IV. 


PART IV. PLATE VI. 


GW Hawes del E Crsand, lith New Haven 


PLATE VIL. 


PART IV 


ree. EXE, 


FB 


oo 


E.Crsand, lith New Haven. 


GW. Hawes. del. 


PLATE VI. 


E.Crisand, lith New Haven. 


GW. Hawes. del 


PLATE IX. 


IV. 


PART 


£E.ortsand, lith New Havei. 


W Hawes del 


ic] 


PLATE X. 


PART IV. 


GW. Hawes del E Crisand, lith. New Haven 


PART We PLATE XI 


a. oe 
TW Hawes, del E.Crisand, lith New Haven. 


PART V. 


ECONOMIC GEOLOGY. 


CHAPTER I. 


METALS AND THEIR ORES. 


Eas geology is an account of rocks with reference to their 
pecuniary value, or immediate application to the wants of society. 
A full treatise would include a description of the methods of mining, 
quarrying, and metallurgy; chemical processes for the manufacture of 
various salts; account of the manufacture of quicklime, glass, and earthen- 
ware; the discussion of the nature and origin of metalliferous deposits ; 
the uses of peat in agriculture, etc. Our work will be mainly the de- 
scription of the localities, modes of occurrence, and quantity of materials 
valuable for economic purposes. Very few of the industries involved 
in the manufacture of mineral materials have become thoroughly estab- 
lished in New Hampshire, so that our contributions to the perfection of 
the processes employed cannot be extensive. Allusion will be made 
from time to time to methods of manufacture or processes of reduction, 
so far as seems desirable. For convenience, this part will be divided into 
three chapters,—first, that relating to the occurrence and extraction of 
the metals; second, facts about the supplies of mineral materials used 
for building and the manufacture of useful articles; third, an account of 
deposits serviceable to the interests of agriculture. A part of this topic 
has been already discussed in the chapter upon Agricultural Geology in 
Volume I. 

The following metals occur in considerable abundance in the state 
(insomuch that the question will be raised with each, whether its ores 


4 ® ECONOMIC GEOLOGY. 


can be mined advantageously): Gold, silver, copper, iron, lead, zinc, tin, 
bismuth, manganese, arsenic, and molybdenum. 


GoLp. 


Dr. Jackson discovered minute quantities of gold in the magnetic pyr- 
ites of Canaan and Enfield. He made very extensive examinations of 
several lots of the ore, and thoroughly satisfied himself that the metal 
existed in too small amount to be of any practical value. 

I have had specimens sent me from a great many towns in the state, 
believed to contain gold, and find most of them of no value. Those who 
are inexperienced mistake yellow pyrites and mica for gold. In other 
cases, as quartz is known to carry this metal in auriferous countries, peo- 
ple are convinced that, if a vein of this substance is found in their neigh- 
borhood, it must be rich in gold. In Volume II we have described enor- 
mous beds or veins of this rock, some of them traceable for a hundred 
miles. These have been opened at several places, but have nowhere been 
found profitable, if, indeed, the presence of gold in small amount is not a 
delusion. The wishes of the proprietors, coupled with duplicity on the 
part of prospectors or speculators, may often lead to false reports of the 
presence of gold. I have seen nothing to convince me that gold exists 
in the following large beds or veins: The Hooksett and Manchester 
ranges of quartz, seen between Royalton, Mass., and Denmark, Me.; the 
beds in the Rockingham mica schist in Londonderry, Raymond, North- 
wood; the smaller patches in Concord, Holderness, Sandwich, Warner ; 
those on the west side of the state, in Richmond, Keene, Surry, Acworth, 
Alstead, Croydon, Newport, Grafton, etc. Add to these the beds of 
quartz found in the Bethlehem, Huronian, and Cods groups. 


I have notes of operations upon some of these beds. In Sandwich, some openings 
were made in 1877, in the ‘* White ledge,” one mile north-west of Sandwich centre, 
with the high-sounding name of ‘‘ Diamond Ledge Gold Mine.” No pure gold is visi- 
ble. The operators claim an average yield of $49 to the ton. 

In Ossipee, a quartz band from four to eight rods wide occurs on the south side of 
Pocket hill, near the house of Obed Sanders. The quartz is unusually crystalline and 
open, traversed by numerous veins of the same material, and also by granite. No 
metals or ores are seen in it. 


The ‘silver mine” in the same town, on the land of Jonathan D. Sias, presents sim- 


METALS AND THEIR ORES, 5 


ilar lithological features and dimensions. The metalliferous part is on the south-east 
wall of the quartz, separated by a width of eight inches of fuller’s-earth from a trap 
dyke. A shaft has been sunk 36 feet. The adjoining rock is granitic gneiss. The 
ore is scantily disseminated through a width of four to seven feet, sometimes pinching 
out entirely. It consists of galena, magnetite with blue stains, copper and iron pyrites, 
and zinc blende. This opening was made in 1876. 

In the north part of Wakefield, on the land of Ira Hammond and S. B. Ames, is a 
similar band of white quartz with scanty veins of galena, blende, iron and copper pyr- 
ites. Mined in 1876, and two shafts sunk to the depth of Io and 17 feet. 

In the north-west part of Strafford there is another opening in one of these beds, 
much talked of by the prospectors. I have seen the beds, but not the openings. The 
quartz is of remarkable extent and purity. I should not expect any of these ‘‘ mines” 
to prove profitable. 


The following is the report of Mr. Huntington upon the prospect of 
finding gold in Pittsburg, made in 1871. There is reason to believe that 
explorations for gold in this town may be successful : 


ALLUVIAL GoLp oF INDIAN STREAM. 


In that part of Quebec Province that lies between the St. Lawrence, 
Maine, New Hampshire, and Vermont, the existence of gold in the allu- 
vium has been known for many years. It is estimated that the area 
over which it extends comprises more than ten thousand square miles. 
The gravel containing gold rests generally upon metamorphic schists, 
some of which are associated with diorites and serpentines. Mr. A. 
Michel compares the gold deposits of Lower Canada with those of 
Siberia. In the Ural and Altai mountains the auriferous gravels are 
almost always found reposing on schistose rocks, very rarely granitic or 
sienitic, as along the Pacific in North and South America. He further 
says, that the gold in Quebec Province, “whether in large or small 
.grains, is generally so smooth, so much rounded and worn by friction, 
that it appears to come from some distance.”” * * * “The condi- 
tion of the gold shows it to have been, for the greater part, at least, 
detached, rounded, and ground by erosive action of currents of water.” 

In the town of Ditton, which borders on New Hampshire, and is 
immediately north of the head waters of Indian stream, alluvial gold 
washing, by sluicing, has been carried on for several years. The place 
where the most extensive operations are is on a branch of Salmon river, 


6 ECONOMIC GEOLOGY. 


three and a half miles from the boundary. The stream at first runs a 
little south of east, but at the point where the principal excavations have 
been made it turns and runs northward. So that here there is a basin 
in which the drift has accumulated to the depth of fifteen or twenty 
feet. The upper portion, which consists of a very coarse gravel and has 
a thickness of three or four feet, was probably deposited by the stream, 
and it contains no gold. The portion below consists of both coarser and 
finer material, from clay to boulders eight or ten inches in diameter. 
Through this the gold is irregularly distributed, but it is most abundant 
near the bed rock, which here consists of an argillaceous schist, quite 
fissile, and containing numerous cavities filled with a yellowish powder. 
This mine has been worked during the summer months every year since 
1866, and from ten to twenty men have been employed by the proprietor, 
J. H. Pope, M. P. 

As gold was found immediately north of New Hampshire, and since 
the drift through which it was distributed came from the northward, the 
drift stria where they were noticed being S. 28° E., there is every proba- 
bility that gold will be found within our limits. But prospecting in a 
wilderness ten or fifteen miles from the habitations of men, where the 
places can be reached only on foot, requires a great amount of time and 
labor, and therefore our explorations have not been so thorough as they 
might have been under more favorable circumstances. 

In my explorations on Indian Stream, I employed an Indian, Mr. A. A. 
Annance, who was formerly a student at Hanover, but who now prefers 
hunting moose and trapping sable to studying calculus and reading 
Greek. The points examined were on and near Indian Stream, about 
three and a half miles from the boundary. The stream here is quite 
rapid, and on either side the hills rise three and four hundred feet above 
its bed, while every few rods, either from the east or the west, it receives 
a tributary. The rocks here, as elsewhere on Indian Stream, consist of 
argillaceous schists. These are often so wrinkled and corrugated that 
it is difficult to determine the dip, while elsewhere, especially where the 
rock is of a coarser texture, the flexures and contortions are not seen. 
In every respect the rocks are similar to those of Ditton. Immediately 
on Indian Stream the gold is chiefly found in the fissures of the schist, 
which is here so fragile that it is easily broken up by picks. A quarter 


METALS AND THEIR ORES. 7 


of a mile from the stream we found the characteristic drift of this sec- 
tion. It consists of a bluish clayey gravel, and contains boulders of 
schistose rocks, and it has a depth, where we excavated, of three and 
four feet. The gold seems to be distributed through the entire mass, 
though it is nowhere very abundant; yet, when the road that was several 
years ago projected from Connecticut lake to the boundary is con- 
structed, this section will be well worthy of a thorough exploration, 
especially as the streams are rapid, and the descent of the bed-rock is 
sufficient to carry away the loosened sand if the hydraulic process is used. 
It has been estimated* that “earth which contains only the twenty-fifth 
part of a grain of gold, or about two mills’ worth in a bushel, will pay 
about two dollars a day to a pipe.’—J. H. H. 


Tue Ammonoosuc GoLp FIELD. 


Under the appellation of Ammonoosuc Gold Field is included the terri- 
tory occupied by the auriferous slates and schists along Connecticut river, 
supposed to belong to the Huronian and Cambrian series, lying mostly 
in New Hampshire, but partly in Vermont, and possibly extending be- 
yond the sources of the Connecticut into Maine and Canada. The south- 
ern limit is near Bellows Falls. Explorations of this field have been 
desultory and disconnected. The earliest discovery of free gold in any 
part of it, so far as can be ascertained, was made by Mr. Hanshet, in 
Plainfield, not later than 1854. This was but a short time before Moses 
Durkee, of Lebanon, washed gold out of alluvium in both Hanover and 
Lebanon. In the report upon the geology of Vermont,} published in 
1861, Springfield, Vt., is given as a gold locality. It was obtained from 
the gravel, and but a short time previous, according to my note-book. 
No other proof of the presence of gold in the Connecticut valley is cited 
in that report, though its existence there is “strongly suspected.” In 
1858, while acting as assistant on the Vermont survey, I measured a sec- 
tion, from Lake Champlain over Camel’s Hump and Mt. Washington, 
which crossed this auriferous field in Littleton.§ The similarity of the 
ledges to those in the great talcose schist and gold-bearing formations 
just east of the Green Mountains led us to regard them of the same age 


* Mining Statistics west of the Rocky Mountains, 1870, p. 478. 
} Page 683. } Page 849. § Page saz. 


8 ECONOMIC GEOLOGY. 


and character. In my report on the geology of Maine, I have described 
the supposed continuation of this formation as probably auriferous; and 
it may be connected with the gold rocks upon the Upper Chaudiére and 
St. Francis rivers of Canada, described by Sir W. E. Logan, and said to 
have yielded masses of gold weighing 126 pennyweights.* 

The first discovery of gold in Lyman was made by Prof. Henry Wurtz, 
of New York, in August, 1864. Prof. Wurtz visited the locality and the 
neighborhood in July and September, 1864, and in December, 1866. He 
sent several specimens of galena to Dr. John Torrey, to be assayed, re- 
questing that they might be tested for gold as well as silver. The third 
sample submitted to Dr. Torrey, coming from the Orchard vein of the 
New Hampshire Silver Lead Company, contained silver at the rate of 
56.95 ounces, and gold at the rate of 1.006 ounces to the ton of 2,000 
pounds. Wurtz’s reports were issued by the Silver Lead Company in 
1864; and subsequently he prepared for the American Fournal of Min- 
ing} a full account of his connection with the discovery, and suggested 
very appropriately that the whole auriferous district be called the Ammo- 
noosuc Gold Field, as it is drained by the Ammonoosuc river and its 
tributaries. He remarks of the Lyman district, that the “history of this 
gold field presents, probably for the first time, the peculiarities of a first 
discovery in the sold rock, and not, as usual, by the tracing up of gulch 


” 


gold to its home in the lodes.”’ The appropriateness of the name, coming 
from so high an authority as Prof. Wurtz, led us to extend it over the 
whole area of the group in New Hampshire and Vermont, as has been 
often mentioned in the previous volumes of this report. 

In 1865, both J. Henry Allen and Charles Knapp, independently of 
each other, discovered free gold on the David Atwood estate in Lisbon. 
This led to the organization of the Lisbon Gold Mining Company, on 
the 28th of February, 1866, with a nominal capital of $240,000. Previ- 
ously to this organization a little work, or “prospecting,” had been done, 
and subsequently three considerable excavations were made in the vein. 
The first is in a swampy piece of land on George brook. This has been 
sunk to the depth of 94 feet, the first 35 vertical, and the remainder at 
an angle of 45° or more, upon the supposed dip. It is said that a dyke 


* Geological Survey of Canada. Report of Progress from its Commencement to 1863, p. 437. 
+ Sept. 12, 1868, 


METALS AND THEIR ORES. 9 


of trap is connected with the vein in the foot-wall as low as fifty feet. 
The greatest amount of free gold showed itself within twenty-five feet 
of the surface. The gangue of the vein is quartz, about one twentieth 
part being composed of magnetic iron pyrites or pyrrhotite, with a slight 
sprinkling of yellow copper pyrites or chalcopyrite. The assays of the 
rock were said to indicate at least $60 to the ton. It is probable that 
the pyrrhotite contains gold, as the best specimens show free gold inter- 
mingled with it. It is estimated, by good authority, that about three 
hundred dollars have been obtained practically by milling from this 
mine. 

The second opening, a few rods up the hill on the south bank, was 
sunk 30 feet. The third, much farther south, was sunk 25 feet. All the 
openings indicate a vein over four feet in thickness, similar to that already 
described, and bounded by a hard quartzite resembling gneiss. The vein 
is about an eighth of a mile removed from a clay slate. 

The company were not very successful in extracting the gold from 
this mine, and ceased to excavate in December, 1866, allowing the open- 
ing to become filled with water. They then bought one half of what is 
known as the Dodge mine, and since the abandonment of the first, have 
wrought the second diligently. Their capital stock has been reduced to 
$48.000. 

The Dodge Mine. In June, 1866, Mr. J. H. Barrett, while laboring on 
the Dodge farm in Lyman, nearly two miles by road from Lisbon village, 
discovered a stone projecting from the wall which contained a yellow 
substance resembling gold. The specimen was sent down to S. K. Fisk, 
of Lisbon, who pronounced the yellow mineral iron pyrites; but upon 
cleaning the other face of the stone discovered a large sprinkling of gold, 
the finest specimen ever found in New Hampshire. This discovery led 
to a search for the vein. Three or four shallow openings were made, 
and an association formed to work one half the property, known as the 
Dodge Gold Mining Company, with a nominal capital of $75,000. The 
Lisbon and Dodge companies have worked this mine jointly since the 
early part of 1868, each transporting its share of quartz to the mills at 
Lisbon village. The Dodge mill commenced operations March 12, 1868, 
on the north side of the river. Each mill has ten stamps, and is capable 


of crushing and amalgamating eight tons in twenty-four hours. 
VOL. Vv. 2 


Io ECONOMIC GEOLOGY. 


The history of the operations of the Dodge and Lisbon mines has 
been quite varied. The Dodge company worked the mine and milled 
the quartz from the date just mentioned to the last part of 1869. B. F. 
Martin, the president, states that the sum of $24,500 was obtained while 
it was under his care. For the six months from December, 1869, to 
June, 1870, the property was leased to E. L. Hall and John McCall. 
Dr. Rae says they obtained $6,570 during this time. Others estimate 
the amount higher,—about 30 tons per week of ore, valued at $12, for 
26. weeks, making over $9,000. Messrs. Fay and Wilmarth next leased 
the property for six months in 1870-71, and are thought to have taken 
out $2,000. Inthe spring of 1873, Dr. Julio H. Rae leased the property, 
and applied a process of his own to the separation of the gold from the 
quartz. He claims to have taken out $3,500 in July and August of that 
year. He found an average of $25 to the ton at first, but afterwards 
only $18 was obtained. Up to the time of the formation of the Electro- 
Gold Mining Company, the entire amount of gold milled was $36,570. 
Dr. Rae says it would be proper to add $5,000 for the supposed stealings, 
and half as much for the value of the specimens that have been carried 
away. 

This new company wrought the mine and mill successfully for two or 
three years. From several letters written by the president, Dr. Rae, I 
cull the following : 

Under date of October 17, 1873, he writes: 


Enclosed please find copy from book of one week’s run, made while experimenting : 


Monday, one ton gross yielded . . i. F ; . 1550 grains of gold. 
Tuesday, te es i ‘ ‘ A 3 : . 1620 es ss 
Wednesday, ‘‘ Hs as . . 5 . . . 1850 oe #6 
Thursday, ‘ at ue n ; F H . - 2240 es % 
Friday, “ sf ze A a : 3 : - 1790 * 
Saturday, 600 pounds yielded é e . ‘i i . 1220 fe ee 
Monday, 1750 ss a . . r : 3 . 1590 Be as 
Tuesday, one ton gross ‘ : z 5 F . 2000 es ne 


Under date of March 25, 1874, he writes,— 


Our ore has averaged $19 per ton, the finest varying from 930 to 955, gold,—silver, 
42 to 65. The ore has run down to about $1.25 per ton, and the richest of which I run, 
probably about three tons, went as high as $95. The mean average of the ore can be 


METALS AND THEIR ORES, II 


safely estimated at $19 per ton, if judgment is exercised in culling. The vein being 
very wide—18 feet—mining is cheap; but we cull our ore about fifty per cent., making 
the ore cost, for mining and culling, about $2 per ton. Add $1 for cartage, and $1.50 
for milling, or work in mill in reducing ore to bullion, and you will find that the cost of 
mining and milling is $4.50 per ton of 2,240 pounds. 


The director of the U. S. Mint reports the receipts of gold from New 
Hampshire for the year ending June 30, 1875, to be $5,200.92. For the 
year following, the amount was $2,731.74. A figure given in the direct- 
or’s report for the amount received from New Hampshire up to the last 
mentioned date probably denotes the total received from the Electro-Gold 
company: it is $10,233.68. If this sum be added to the total known to 
have been extracted prior to 1873, viz., $36,570, we shall have $46,803.68 
as the total amount of gold mined at Lyman prior to 1876. Mr. Willard 
Parker, of Lisbon, who has been familiar with the whole history of the 
extraction of the gold in Lyman, estimated the whole amount extracted 
to the same date at $48,000. The close coincidence of our two indepen- 
dent estimates leads to the belief in their essential correctness. There 
has been some gold taken from the vein since 1876, so that it may be 
proper to say, in round numbers, that $50,000 of the gold coin in circula- 
tion in the United States has been derived from New Hampshire during 
the past ten years. : 

The tract of land occupied by the Dodge and Lisbon companies com- 
prises about 170 acres in the east part of Lyman, and is defined upon 
the map opposite page 296, Volume II. The companies are engaged in 
litigation at the present time rather than in the development of their 
mines. The land has been divided into sections of 500 feet each, that 
at the southern end being owned by the Dodge company, and the second 
by the Lisbon company; the third by the Dodge, the fourth by the Lis- 
bon, and so on. The improvements made are upon the first sections 
respectively. 

The Dodge mine was leased for a time to J. H. Paddock & Co., from 
about March 1, 1874, who used the mill upon the east side of the river 
at Lisbon village. I have no facts about the production of gold by this 
firm, nor of that obtained by the Lisbon company after the Electro-Gold 
company ceased to operate. 

The Dodge Vein, The formation carrying the auriferous veins of this 


12 ECONOMIC GEOLOGY. 


type has been described in Volume II as the Cambrian clay slate. 
There is little mention made of the veins, save in the catalogue of 
the specimens obtained from the Ammonoosuc district, and their delin- 
eation upon the map on page 296. The quartz is somewhat glassy, 
whitish, except where it has been stained by the decomposition of pyr- 
ites, and nearly pure. Masses of slate, crystals of pyrites, ankerite, and 
galena are scattered through it. It is common to find spangles of free 
gold in the quartz, most conspicuously at the boundary between the 
quartz and fragments of slate in it. The ankerite is a characteristic 
mineral of all the auriferous veins of the Connecticut valley clay slates. 

The question arose early as to the proper source of the gold. All that 
can be seen macroscopically is in the clear quartz. In 1869, I had the 
general average of the vein assayed, and also each constituent by itself, 
except the galena, which was of rare occurrence. The average was 
taken twice;—first, a picked sample from the vein; second, a portion of 
several hundred pounds’ weight that had been pulverized in the mill for 
practical extraction. According to Prof. C. A. Seely, the amount of gold 
in both the averaged samples was essentially the same, or $18.90 to the 
ton. Of the constituents examined separately, taken from the same 
pile, the clear quartz yielded $18.11 of gold to the ton. The pyrites 
occurring in the quartz and in the slate both yielded traces of gold, but 
not enough to be measured, the latter affording the greatest amount. 
Neither the slate nor the ankerite afforded any trace of gold. If it were 
allowable to generalize from these single determinations, it were easy to 
say that 95 hundredths of the gold comes from the clear quartz, and the 
balance from the pyrites in the vein. There is not very much of this 
mineral present, but sufficient to attract attention, and to be saved by 
some of the manipulators. Seeing a pile of this pyritiferous residue in 
the rooms of the Electro-Gold company’s mill, I begged samples for 
assay. Prof. Blanpied found no gold in it. The species seems to be the 
common bisulphuret,—not the magnetic variety, nor mispickel, which is 
auriferous in this neighborhood. 

The gold, as obtained from this vein, is very pure. I examined twenty- 
four of the returns from the mint, and found the average of them to be 
916.8 parts of gold to 83.2 of silver. This is purer than the average of 
this metal in auriferous countries; that of California is 880 in 1000; 


METALS AND THEIR ORES. 13 


Australia, 925.; the Chaudiére region of Canada 885 to 900; while from 
Nova Scotia the gold is very nearly pure. 

The method of extraction first employed is the ordinary stamp process, 
ten small stamps rather lighter than usual, with copper and blanket 
amalgamation. It is thought by those much experienced in quartz mill- 
ing to have been carried on in a crude manner, yet the amount saved 
has been a fair percentage of the assay yield. There were two of these 
mills, one on each side of the river at Lisbon village. 

With the advent of the Electro-Gold company the Thunder-bolt crusher 
replaced the stamps. The rock was heated, or partially roasted. It was 
then crushed dry, and the powder placed in cylinders with water and 
quicksilver, thirty pounds to a ton of ore. This cylinder revolves four 
hours, and the sands flow into a dolly tub, afterwards passing over blan- 
kets. The sulphurets are caught mostly in the tub, and saved for fur- 
ther treatment. The blankets catch the fine gold, and are changed every 
four hours. This mill could treat five tons of rock in ten hours. It was 
the most successful of the various methods tried in New Hampshire. It 
has since been used more extensively in Virginia. Being of little use for 
the extraction of gold from sulphurets, Dr. Rae has added a desulphuriz- 
ing furnace to his works, enabling him to treat ores otherwise intracta- 
ble. We present herewith the original specifications of the patent de- 
scribing this process. 


123,982. United States Patent Office. Fulio H. Rae, of Syracuse, New 
York. Lmprovement in Voltaic Amalgamators for Gold and Silver. 


Specification forming part of Letters Patent No. 123,932, dated February 20, 1872. 


To all whom it may concern: 

Be it known that I, Julio H. Rae, of the city of Syracuse, in the county of Onon- 
daga and state of New York, have invented a new and useful improvement in voltaic 
amalgamators for ore; and I do hereby declare the following to be a full, clear, and 
exact description thereof, which will enable those skilled in the art to make and use 
the same, reference being had to the accompanying drawing forming part of this 
specification, in which drawing,—. 

Fig. 1 represents a longitudinal vertical section of my invention. Fig. 2 is a plan 
or top view of the same. Fig. 3 is a detached longitudinal central section of the 
voltaic cylinder, which forms one of the principal parts of my amalgamator, in a 
larger scale than the previous figure, the line x x, Fig. 4, indicating the plane of 


14 ECONOMIC GEOLOGY. 


section. Fig. 4 is a transverse section of the same in the plane y y, Fig. 3. Fig. 5 
is a detached section of the washer in a larger scale than the first two figures. 
Fig. 6 is a plan or top view of the same. 
Similar letters indicate corresponding parts. 
This invention consists in the arrangement of a voltaic pile in the interior of 
‘ aSheets--Sheet!, 20 amalgamating-cylinder in 
JH. RAE. such a manner that, when 


Improvement in Voltaic Amalgamators for Gold and Silver said cylinder is charged with 
No. 123,932. Patented Fob. 20, 1872, : 
the pulverized ore, quicksil- 


Pug t 3 

4 ver, and proper chemicals, 
and then revolved, the gal- 
4 4 vanic current excited in the 


pile materially promotes the 


amalgamating process. Also, 
BU SEEPS in the arrangement of a rod 


= e, f extending centrally through 

; the amalgamating - cylinder, 
a and forming the support of 
q the voltaic pile, the copper 
elements of which connect 
with one head, and the zinc 
‘elements of which connect 
with the opposite head of 
said cylinder, in such a man- 
ner that the elements are 
securely retained and not lia- 
ble to get out of position by 
the revolution of the cylin- 


Wilrg gen, tentos. der; and at the same time 
Mind hito gor the voltaic pile offers the 
M1 Moe, least possible obstruction to 


the revolving motion of the cylinder. Further, in the arrangement of one or more 
voltaic cylinders in a receiving-tank which connects with an agitating-tub in such a 
manner that the pulp discharged from said voltaic cylinder or cylinders can be washed, 
and the floating particles of quicksilver contained therein can be saved. Also, in 
combining the voltaic cylinders, the receiving-tank, and the agitating-tub with one or 
more washers, composed of conical copper-lined vessels, each of which contains a hol- 
low inverted truncated cone suspended from a water-supply pipe, and provided with a 
large number of small holes in the bottom and lower part of its outer shell, in such 
a manner that, by the up current of the jets of water discharging from said holes, the 
particles of mercury still mixed with the tailings received in the washer are recovered, 
while the tailings flow off through a copper-lined gutter, the copper lining of which 
retains the last traces of mercury which may be still mixed with the tailings. 


METALS AND THEIR ORES. 15 


In the drawing, the letters A A designate cylinders, each of which is constructed 
as shown in Figs. 3 and 4 of the drawing. Through the centre of each of these cylin- 
ders extends a rod, B, the ends of which have their bearings in sockets formed on the 
interior of the heads of the cylinder, and on this rod are secured the elements of a 
voltaic pile, C. All the copper elements of this pile are connected by a wire, a, which 


is in contact with one of the aT 3 Shoets~Shoet 2. 
heads of the cylinder, while Improvement in Voltaic Amalgamators for Gold and Silver. 
the zinc elements are con- No 123.932. Patentod Fob. 20, 1872, 


nected by a wire, @, which is 
in contact with the opposite 
head of said cylinder. By 


this arrangement I obtain a 


voltaic pile of great power in 


a comparatively small space ; 
but it must be remarked that 
one or more voltaic piles 
might be arranged in the 
interior of the cylinder in any 
desired position, and I do not 
wish to be confined to the 
precise arrangement of the 
voltaic pile which I have 
shown. Each of the cylin- 
ders A is provided in one 
side with a man-hole, through 
which the cylinder can be 
charged and discharged, and 
which can be firmly closed 
by a man-hole plate «. 
Through the side of the cyl- 
inder opposite the man-hole 


extends a pipe, @, which can 
be opened and closed by a stop-cock, ¢, and which serves to draw off the quicksilver 
at the proper time, as will be hereafter more fully explained. From the outer surfaces 
of the heads of the cylinders project gudgeons, e’, which have their bearings in the 
edges of a tank, D, which is intended to receive the pulp and conduct it to the agitat- 
ing-tub E. From the bottom of this tub rises a tube, 7, to a level with the top edge, 
and this tube forms the bearing for a vertical shaft, g, from which extend radiating 
arms #, carrying the agitators z, which extend down near to the bottom of the tub E, 
as shown in Fig. 1. In the side of this tub are three pipes, 7, one above the other, 
and each provided with a stop-cock; and from the bottom of the tub, just beneath the 
pipes 7, extends the discharge-pipe #, which leads to the first washer F. An enlarged 


16 ECONOMIC GEOLOGY. 


view of this washer is shown in Figs. § and 6 of the drawing. It consists of a conical 
tub, lined with copper, and in this tub is contained a double-walled inverted truncated 
cone, G, which is suspended from a water-supply pipe, H, and which is perforated 
with a number of small holes in its outer bottom and in the lower portion of its exter- 
nal jacket, so that the water admitted through the pipe H discharges from the cone G 


1H. RAE. 3 Sheots--Shoet 3. in a large number of fine jets, 
Improvement in Voltaic Amalgamators for Goid and Silver. producing an upward current. 
No. 123,932, Patented Feb. 20, 1872, [9 The washer F is placed ona 


table, with a spout, Z, extend- 
ing over a second washer, F’, 
which is constructed like the 
first washer, and the dis- 


charge-spout / of which ex- 


tends over a gutter, I, lined 
with copper. 

In using my invention I 
first reduce the ore to a fine 
powder, and then I introduce 
the same, together with a 
suitable quantity of water, 
quicksilver, and suitable ex- 


citing chemicals, into the 
cylinder or cylinders A. The 
chemicals which I use are 
common salt, or such acids 
which, when brought in con- 
tact with the voltaic pile, will 
excite a galvanic current. In 
regard to the quantity of 
quicksilver and the character 
and quantity of the exciting 
agent used, reference must 
always be had to the nature of the ore and to the electric affinities of the metals con- 
tained in the ore about to be washed. After revolving the cylinder or cylinders from 
three to four hours, the quicksilver is drawn off through the pipe or pipes d. Then 
each cylinder is again revolved for a few minutes for the purpose of fluidizing the pulp, 
when the man-hole plate is taken out, and the whole contents of the cylinder dis- 
charged into the receiving-tank D, whence the pulp gradually discharges into the 
agitating-tub E. In this tub the pulp is agitated, the amalgam being precipitated, 
while the tailings are drawn off through either of the pipes 7, according to their spe- 
cific gravity. The amalgam which collects on the bottom of the tub is removed from 
time to time, while the tailings pass into the first washer, F, where small particles of 


METALS AND THEIR ORES. 17 


mercury, still mixed with the tailings, are precipitated or retained by the copper sur- 
face of the washer, while the light tailings are carried up by the up current of water 
produced by the jets of the cone G, and discharged over the edge of the washer F 
upon the table 7, whence they run down into the second washer F’, to be treated in 
the same manner as above. From this second washer the tailings pass into the gut- 
ter I, the copper lining of which retains the last traces of mercury which may be still 
mixed with the tailings. 

What I claim as new, and desire to claim by letters patent, is,— 

1. The arrangement of one or more voltaic piles in the interior of an amalgamating 
cylinder, substantially as described. 

2. The rod B, extending through the centre of an amalgamating cylinder, and sup- 
porting the elements of a voltaic pile, in combination with wires @ 4, one forming a 
connection between the copper, and the other between the zinc elements of the pile, 
substantially as set forth. 

3. The arrangement of one or more voltaic cylinders in a receiving-tank communi- 
cating with an agitating-tub, substantially in the manner shown and described. 

4. The combination, with one or more voltaic cylinders, a receiving-tank, and an 
agitating-tub of one or more washers, F F’, substantially as set forth. 

5. The double-walled hollow inverted cone G, communicating with a water-supply 
pipe, and provided with jets in its bottom and outer jacket, in combination with a 
washer, F, constructed substantially as described. 

JULIO H. RAE. 

Witnesses : 

W. HaAurrF, 
J. Van SANTVOORD. 


A gentleman familiar with milling has written the following sketch of 
the practical working of Rae’s process in Virginia: 


The first important difference between this and the common milling process is, that 
no water is introduced into the mortars, and the rock to be crushed must be perfectly 
dry. Inall mills the degree of fineness to which the rock is powdered is regulated by 
a screen, through which alone the pulverized ore finds egress from the mortars. 

In Rae’s method, very fine screens are used, so that the rock is reduced to a very 
minute powder before it escapes from the batteries. It is then carried by an elevating 
belt to a platform above the battery, where it is emptied into a car large enough to hold 
one ton of crushed rock. When this amount is received, the car is removed and an- 
other placed in its stead. The car already charged with the ton of powdered rock is 
rolled forward till it is above the amalgamating machinery. 

This consists of a large tank so inclined that fluids will readily flow from it through 
a.vent in the lower end. Across this tank, their axis resting on journals supported by 
its sides, are two cylinders, each seven feet long and four feet eight inches in diameter. 

VOL. V. 3 


18 ECONOMIC GEOLOGY. 


On one side of each cylinder, half way between the ends, is a large opening called a 
manhole; on the other side, opposite, is a large faucet. By an ingenious contrivance, 
the manhole can be closed with absolute tightness. Inside, upon the axis of each cyl- 
inder, is a voltaic pile. Below the vent of the tank is a circular cistern, five feet in 
diameter and one foot six inches high, called a dolly or agitating tub. An upright 
shaft, standing on the centre of the bottom of this tub, is made slowly to revolve. 
From a horizontal cross-piece placed on this shaft, a little above the level of the top of 
the tub, iron teeth one foot six inches long descend. On the side of this tub opposite 
the vent of the tank are four holes, one above the other, through which fluid may pass 
into an amalgamated copper vessel, in shape an inverted hollow truncated cone. In 
the centre of this copper vessel, called a washer, is a hollow sphere pierced with small 
holes. In this sphere terminates a water-pipe connected with a reservoir above, and 
provided with a stopcock to regulate the flow and pressure of the water. Below this 
washer is another, smaller, but in every respect similar in shape and arrangement. 
Such is the amalgamating machinery. The amalgamation is effected as follows: From 
the car above the machinery the pulverized ore is, by a shute, emptied into one of the 
cylinders through the manhole. Water is then introduced till the cylinder is two thirds 
full. Any necessary chemicals, and from fifty to one hundred pounds of quicksilver, 
according to the richness of the ore, are added at the same time. The manhole is then 
closed so tight that nothing can escape; and the cylinder is revolved from three to four 
hours. Then the faucet is opened, and ninety to ninety-five per cent. of the quicksilver 
runs out into a vessel ready to receive it. Another vessel is substituted for this, and 
receives a large portion of the amalgam. The remaining contents of the cylinder are 
then allowed to flow out into the tank, and are washed down into the dolly-tub, where 
they are constantly agitated by the teeth on the cross-piece before mentioned. From 
this tub they pass into the washers, in which the jets of water from the holes in the 
hollow sphere keep the mass constantly in movement, so that any amalgam quicksilver 
or gold which shall have escaped from the cylinder and the dolly-tub sinks to the bot- 
tom of the first, or, at any rate, of the second washer. 


The Dodge shaft was sunk 17 feet in 1867; and the rock taken from 
it yielded $6.25 per ton in the mill. After that, the whole vein on both 
sides was excavated for a length of several rods to the same depth, the 
rock yielding only $3 or $4 per ton. After the return to sinking the 
original shaft, $10 per ton was obtained immediately; and the yield for 
about two years subsequently was nearly the same, averaging $14, and 
in one instance reaching $19. The shaft had been excavated to a depth 
of about 70 feet in 1869; and there are drifts at about 60 feet depth in 
both directions, particularly to the east. The vein is 16 feet wide here. 
The rock from this depth seems to have been most productive. It is 


METALS AND THEIR ORES, 19 


probable that not less than one fourth or one fifth of the total amount of 
gold present in the vein has been lost in the milling process, so that the 
actual results obtained do not fairly represent the true value of the rock. 

Since 1869 three shafts have been sunk upon this vein, two of them 
to the depth of 100 feet, the third about half as much. The quality of 
the rock at various parts of the shafts and cuttings is not uniform. 
Some who have engaged in milling the quartz became discouraged on 
account of the small yield. By protracting on a scale, when the facts 
were fresh in my mind, the rich and poor portions of the quartz, I dis- 
covered a uniform method of arrangement. The richer portions occupy 
a definite part of the vein called a “shoot” or “chimney” by miners. 
The vein-sheet dips north-west, but the chimney dips to the north-east. 
It cannot be distinguished in the rock except by those handling it every 
day. In other kinds of metaliferous veins this phenomenon is very dis- 
tinct, showing itself in a swelling of the mass, forming a bonanza. The 
thickness of the quartz vein is constant, and where it increases in rich- 
ness the bulk is the same as before. The best method of discovering 
the rich and lean ore is by experiment. 

There is a second quartz vein upon these properties, about eighty feet 
to the north, but it has not proved productive. Excavations made to the 
south-west upon the first Dodge lot have shown the presence of the orig- 
inal vein nearly to the edge of the property. 

T learn that operations upon this vein are to be resumed immediately, 
or in the spring of 1878. 

Other Quartz openings. A few other veins similar to the above occur 
in Lyman and its vicinity. One of the most noted is the Bedell mine, 
about a mile farther west. The mineralogical character is the same as 
that just described. It is two feet wide. Specimens showing much free 
gold are easily obtained. I panned out several pieces of gold from a 
shovelful of earth scraped from the top of the ledge, and saw much richer 
yields in the hands of others. A reliable assay of it in 1869 showed £12 
to the ton of gold present. There is more galena than usual in the vein, 
carrying $33 of silver to the ton. A shaft has been sunk to the depth 
of 20 feet. 

Near the Haviland copper mine is the Hartford or Moulton mine. A 
shaft has been sunk about 100 feet. At the depth of 23 feet the quartz 


20 ECONOMIC GEOLOGY. 


vein, not of much width, is said to have assayed $30 in gold and $10 in 
silver to the ton. I have seen specimens of free gold from this mine. 

Other openings are upon the clay slate area close to the conglomerate 
near stakes V 14 and 15 (Vol. II, p. 296), or the Bartlett mine; the west 
part of Jason Titus’s farm in Lyman; upon B. Dow’s land, near stakes 
B 19 and 20; and in Bath, near the east border of the slate area. Here 
Smith brook falls over a ledge, at whose base is a tunnel, about twenty 
feet long, made many years since. I found a few specks of free gold in 
the quartz in small veins just below the tunnel. Other quartz veins have 
been recognized while collecting specimens in the field, none of which 
are known to be auriferous by actual test. 

Gold in the Conglomerate. Attention was very early called to the 
presence of gold in the interesting band described with minuteness in 
Volume IT as the auriferous conglomerate. It is regarded as older than 
the veins in the clay slate, and for that reason perhaps is not so rich. 
No extensive excavations have been made in this rock, but it is very 
commonly slightly auriferous. Almost every section of it will furnish 
auriferous samples. Authentic assays have been made from several 
localities, such as the following: 

A sample from the field north of the Cook and Brown mine (Hiram 
Knapp’s land), afforded to Prof. Seely gold at the rate of 90 cts. to the 
ton. Another determination from a neighboring locality showed 75 cts. 
to the ton. A well known auriferous ledge of this sort is at the house 
of Jacob Williams. A ledge of quartzose conglomerate crops out by 
the roadside, perhaps forty feet high and equally thick. This ledge, two 
hundred and eighty-two feet in length, is one outcrop of a very in- 
teresting division of the gold rocks, whose windings and faultings have 
been carefully studied by us and represented upon both our maps. It is 
an ancient gravel, now consolidated, but it is not known whether the gold 
was deposited in the original placer, or introduced in small veins at the. 
subsequent period of elevation. The company’s statement represents 
that assays of from six to eight hundred pounds of rock have given 
them from five to seven dollars* of gold to the ton, and on account of 
the facility with which thousands of tons can be obtained from the mass, 
think that an average yield at these rates would be remunerative. The 


* In one case, $9.99 in currency. The latest experiment shows $3 per ton. 


METALS AND THEIR ORES. 2I 


whole width is traversed by segregated veins in which pyrites and an- 
kerite are abundant, while specks of galena and copper have been seen. 

An opening once greatly talked of is situated on the Steery farm east 
of Williams’s. It has been known as the “Dow ledge” at the Pittsburg 
mine. It is a cliff of the same conglomerate, 50 or 60 feet high, and has 
been opened slightly. 

On the most eastern band of this rock is the “Gordon mine.’ There 
are conspicuous masses of pryites, probably magnetic, in this opening 
upon the top of the hill. Only a few blasts have been put in here. The 
conglomerate has assayed from $3 to $10 to the ton. On the west side 
of the crest of this hill a larger excavation has been made in a better 
appearing part of the rock. 

What I conceive to be the same conglomerate has recently been dis- 
covered in the edge of Landaff, about a mile and a half east of Lisbon 
village, and known latterly as the Allen mine. The ledges of it are ex- 
posed upon the “poor-” or town-farm for more than half a mile in length, 
with the usual north-east strike of the country, dipping 50° or 60° north- 
westerly. Upon this farm are several alternations of rock,—five or six 
of quartz, four of slate, two of conglomerate, and a siliceous limestone, 
possibly encrinital. The county rock is regarded as the lower part of 
our Huronian, though resembling the Lyman group. The most valuable 
vein here is from two to four feet wide, carrying much of a dark pyrites, 
staining the hands. Much free gold has been found in it. I have visited 
it twice, and obtained gold readily by washing the crushed selected frag- 
ments. I saw three small excavations. More recent cuttings have been 
made; and the parties interested claim that the quartz averages about 
#30, while the selected specimens of pyrites have yielded at a rate of 
$700 to the ton. They have uncovered the vein for a distance of 100 
feet, and excavated occasionally to the depth of 8 feet. The gold occurs 
mostly in small grains in the decomposed rock, in company with a little 
galena. 

The same conglomerate I have discovered north of the Atwood mine, 
and it is undoubtedly continuous to the similar outcrop on Salmon Hole 
brook (Vol. II, p. 324). It runs towards the coarser conglomerate of 
North Lisbon. It is claimed to extend in the other direction—the south- 
west—towards North Haverhill. 


22 ECONOMIC GEOLOGY. 


THE GRAFTON Company. 


One of the curiosities of mining in New Hampshire has been illus- 
trated by the history of the Grafton Gold Mining Company, organized 
near the beginning of the year 1869. The property is near the west 
corner of Lyman. It was first known as the Davis & Thayer, and after- 
wards as the Wiggin & Davis property. I visited it September 14, 1868, 
and May 10, 1869. It lies in the Huronian rocks east of Gardner’s 
mountain, the material being dolomitic and somewhat slaty. At the sur- 
face three veins, each about a foot in width, showed themselves, with 
narrow slaty partings, which became smaller at 25 feet, and are said to 
have entirely disappeared at the depth of 76 feet,—the bottom of the 
shaft,—and to be 8 feet wide. The veins incline south-easterly 55° at 
the surface, and 10° less at the depth of 25 feet, the lowest point at which 
Ihave seen it. The vein is of limpid quartz, with many crystals of quartz, 
dolomite or ankerite, iron pyrites, and galena, besides some free gold, the 
latter most abundant in the upper vein. An immense number of segre- 
gated quartz veins ramify through the dolomitic mass that is brought to 
the surface. 

From several statements shown me by officers of the company, it ap- 
pears that the earlier assays gave over $7 of gold to the ton of rock; and 
at the depth of 76 feet, out of a mass weighing 50 pounds, Dr. Torrey, of 
New York, obtained gold at the rate of $62.17 to the ton, and of silver, 
$1.33. An examination of the pyrites showed no gold present. About 
forty per cent. of the gangue was shown to be of quartz, and the balance 
chiefly dolomitic. A careful examination of a similar sample by T. C. 
Raymond, of Cambridgeport, Mass., gave the following result: Silica, 
30.3; protoxide of iron, 6.27; lime, 20.6; magnesia, 11.17; carbonic acid, 
32.11;—total, 100.44. This composition led the company to believe that 
the pulverized rock might be used advantageously as a fertilizer after the 
extraction of the gold; and some experiments were instituted to show 
its value. 

The proprietors drove a thriving business in selling this pulverized 
siliceous dolomite for a fertilizer. Even those reputed agricultural writ- 
ers of eminence became interested, and saw great benefits to the soil in 
the application of this powder. No doubt some benefit came, from the 


METALS AND THEIR ORES. é 23 


fact that finely divided materials have the power of absorbing moisture 
from the air; but such unscientific statements as appeared in the testi- 
monials foreshadowed the withdrawal of the substance to serve for a fer- 
tilizer. The following extracts will illustrate: 


Dear Sir: I very gladly write you a statement of the effects of the ‘‘ Grafton Fertil- 
izer” as seen in my garden. Two quarts of ‘‘ Fertilizer” were placed about the roots of 
a grape-vine which had never borne more than a plateful. It is covered with bunches 
of fruit now of a very large size, which will ripen much earlier than usual. I think the 
chemical properties contained in this ‘‘ Fertilizer” will serve to hasten the period of 
ripening of all fruits and vegetables. Melons, cucumbers, and squashes flourish finely 
under its influence. Last year the vines were riddled by the striped bug; this season, 
when they appeared, handfuls of the ‘‘Fertilizer” were scattered over the vines, and 
they rapidly ‘‘vamoosed the ranch.” Not one bug remained! We gathered the first 
cucumbers grown in the town. Melon vines are a mass of yellow blossoms and green 
fruit, and they are not usually prolific so far north. 

The “Fertilizer” is death to all the insect tribe. Carbonic acid is fatal to animal 
life, while it is highly essential to the growth of the vegetable world. The ‘Grafton 
Fertilizer” possesses 32.11 per cent. of this desirable constituent,—solidified,—which, 
added to the lime, protoxide of iron, and silica contained therein, must prove one of 
the most valuable mixtures hitherto discovered. 

For peach-trees, it will undoubtedly be of eminent service. The peach borer can, by 
its aid, be driven from its haunts, and the pear-blight remedied. 


The success of-this fertilizer led E. C. Stevens, of Lisbon, to provide 
a similar material from Lyman, which also had a considerable sale. An 
analysis of it shows it to contain,—Silica, 90.60; lime, 3.27; sesquioxide 
of iron, 3.06; alumina, .31; magnesia, .38; carbonic acid, 1.35; water, 
1.06; alkalies, a trace; gold, a trace. 


GOLD IN THE SULPHURETS. 


Scarcely any topic connected with mining in New Hampshire is of 
greater practical value than the presence of gold in the various sulphu- 
rets, particularly those utilized for the extraction of lead or copper. It 
may frequently be the case that the expenses of mining will be just about 
met by the sales of copper or lead, with little or no margin for profit. 
Should it appear that gold or silver may also be extracted from these 
ores, this fact may insure a profit where otherwise none could be obtained. 
In other auriferous districts, gold is often obtained in abundance from 
sulphurets, and requires peculiar processes for its extraction. I have 


24 ECONOMIC GEOLOGY, 


many statements of proprietors and prospectors, to the effect that our 
sulphurets are auriferous and argentiferous. If they are assuredly cor- 
rect in their estimates of value, a wide field is opened for profitable 
investment. Several circumstances must qualify the value of the esti- 
mates made :—First, all chemists do not agree in obtaining the compara- 
tively large results asserted by some. We have to consider whether this 
is the result of greater skill, on the one hand, or, on the other, to a read- 
iness to stimulate their business. Second, the specimens assayed are 
usually the best of their kind. Third, if several trials have been made, 
the proprietor usually mentions only the best, neglecting to state how 
many have proved unfavorable. We should, however, remember that 
the precious metals may occur in chimneys throughout the sulphuret 
veins as well as in the quartz, so that it is easy to explain a varying rich- 
ness in them. 

First of all, is the statement of Prof. Wurtz, previously quoted, that 
galena at the east base of Gardner’s mountain contains $18.63 of gold to 
the ton of sulphuret. This ore is not very abundant,—not sufficiently so 
to be worth working, in the estimate of the present proprietor. Several 
of the copper properties along the Gardner Mountain range have been 
found to contain gold, up to $15 to the ton, by Prof. F. L. Bartlett, of 
Portland, Me. Such are the Stevens mine in Bath, and the Gardner 
Mountain mine in Littleton. I have had a similar statement as to the 
value of the Paddock copper ore, from C. H. Crosby. 

A friend of mine interested in this question has investigated it quite 
thoroughly for his own satisfaction. It had been stated that the Ver- 
shire copper ore frequently carried $60 of gold to the ton. Others 
claimed a higher figure. He selected for the test a beautiful piece of 
iron and copper pyrites from Corinth, as rich as any that could be found, 
and apparently perfectly free from silica. It was placed in the hands of 
a skilful analyst, with a full statement of the question at issue. In order 
to ensure accuracy, the best method of analysis, at double price, was 
employed. The report states that the amount of gold contained in the 
Corinth ore is 27-100 of an ounce to the ton of 2,000 pounds. This 
would be, in round numbers, about $5 to the ton. The result is valua- 
ble, both disposing of the wild statements afloat as to the great richness 
of many of our sulphurets, and indicating that the Vermont copper ores 


METALS AND THEIR ORES. 25 


are somewhat auriferous. I think I have beeri told that the Vershire 
copper ore has been tested by the company many times, and that it may 
be relied upon to furnish $7 in gold to the ton. J. W. Cleaveland, of the 
Copperas Hill works in Strafford, informs me that several dollars’ worth 
of gold to the ton have been found in the refuse heaps of his establish- 
ment, and a much larger amount in the fresh specimens of copper ore.* 

Capt. Edgar has stated that the zinc blende of Warren carried $60 of 
gold to the ton. This has not been verified in a practical way. 

An interesting question, of both theoretical and practical interest in 
this connection, relates to the chemical condition of the gold in the sul- 
phurets, Is it a sulphuret, or the element itself, free from all combina- 
tion, as in the quartz veins? The fact of the absence of any free gold in 
the pyrites, and its sudden appearance after decomposition, led one mod- 
ern author to revive the ancient alchemistic notion of the derivation of 
gold from the baser metal. It is said by chemists that the pente-sulphide 
of potassium has no effect upon free gold, but will dissolve the sulphuret. 
This reagent has been brought to bear upon auriferous sulphurets, with 
the results claimed; and hence it seems evident that the gold occurs in 
pyrites in combination with sulphur. This latter element needs to be 
carefully eliminated from all gold-bearing ores before the precious metal 
can be amalgamated. 

Cook and Brown's Mine. In 1875 I found renewed activity upon the 
opening called the Cook and Brown mine, by parties known under 
the name of the New England Mining and Reduction Company. About 
five tons of the ore had been worked in Boston, yielding $23.59 to the 
ton; and they desired to test certain improved processes for extracting 
gold from its combination with sulphur. Before thoroughly testing the 
vein, the mill was erected just above Young’s pond; and after its com- 
pletion, owing to irregularities in the vein, not enough ore could be raised - 
to supply the works. A very few feet below the surface, a quartz vein 


* He says,—‘‘ We have found that the yellow deposit from the water flowing out of the adit contains gold in 
small quantities. It has been known for several years that the ore from this mine contains gold; but I was not 
aware that we had silver until Prof. Bartlett, of Portland, Me., made an assay of some of the old spent heaps, 
and found, from the top of a heap that has been undisturbed for twenty years, that it contained four dollars and 
fifty-five cents’ worth of silver and ten dollars of gold to the ton. H. F. Carpenter, of Portsmouth, R. I., has 
been experimenting with the pyrites for the past year, and reports that, from seventy-five to one hundred trials, 
he is able to get sixty dollars of gold per ton; but the gold is an ore, and not in condition to be extracted profit- 
ably.” April rz, 1878. 


VOL.V. 4 


26 ECONOMIC GEOLOGY. 


about ten inches wide was cut into, showing free gold, and that in re- 
spectable quantity. The vein was followed down, and, with several feet 
of the adjoining rock, proved to be highly auriferous. Mr. Hawes’s 
assay of samples selected by me showed the presence of 20 ounces of 
silver, and 2.5 ounces of gold to the ton. Trial with a pan revealed 
considerable gold before the decomposition of the pyrites, and much 
more after calcination. From $70 to $80 to the ton seemed to be a com- 
mon yield, judging by the eye. The material examined was a soft, argil- 
litic schist, full of crystals of arsenical pyrites. Massive layers of this 
same mineral an inch thick had been noticed in the quartz vein. 

After descending 25 or 30 feet, the vein and its accompanying aurifer- 
ous bands disappeared, and has never been found again, and consequently 
mining operations ceased. This opening is almost on the line of fault 
described in Volume I, page 305. The magnitude of the throw—nearly 
1,200 feet—shows that the disappearance of the vein by faulting is not 
singular; but the richness of the auriferous deposit would render it desir- 
able to search for its continuation. 

The presence of so much gold with arsenical pyrites, here and at the 
Atwood and Allen mines, has suggested to me the probability that this 
may indicate the natural affinities of the metal in this district. The for- 
mation in which the Cook and Brown mine is located is the Lyman 
group,—unlike the Dodge vein in the clay slate. Future explorers will 
do well to remember these facts, and not neglect the arsenical ores, as 
they may prove to be the best in the state. 

The mill has been abandoned, after it was discovered that the supply 
of auriferous material from this mine could not be depended upon. A 
lot of fifty tons of auriferous mispickel from Ontario was afterwards 
milled in it, apparently successfully. 

The following sketch of the Crosby process is taken from a prospectus 
issued by the company owning the mill. 


The Crosby mill contains 1 engine of 50 horse-power; 1 donkey-engine, ro horse- 
power; 1 Dodge crusher; 1 pair Cornish rolls; 3 roasting cylinders; 4 Burr mills; 
4 amalgamating tubs; 4 washing tables,—besides elevator, quicksilver strainers, etc. 

The ore is pulverized by passing through the Dodge crusher and through the Cornish 
rollers. The pulverization is however incomplete, a large part of the ore going through, 
as gravel cannot be thoroughly roasted, and must cause loss. A dry stamp-mill would 


METALS AND THEIR ORES. 27 


crush the rock perfectly, or perhaps an additional pair of rollers might answer the pur- 
pose. From the rollers the ore is carried as a powder to the roasting cylinders. These 
cylinders are made of boiler-iron, and are placed in an almost horizontal position on 
friction rollers, and heated to redness from the outside. Inside the cylinders are flanges 
or shelves fixed to the shell, and running parallel with its axes. The ore drops in at 
the feed end; and as the cylinder revolves, is lifted by the flanges, dropped, and thor- 
oughly stirred. From the declination of the cylinder, the ore slowly works its way 
down to the discharge end, roasted or desulphurized. 

The ore is now cooled, ground to a fine powder in the burrhstone mills, washed, to 
free it from soluble metallic salts, and amalgamated. The amalgamation is performed 
in tubs provided with stirrers; and by an ingenious arrangement the quicksilver is 
strained, the amalgam separated, and free quicksilver continuously passed in a fine 
shower through the pulp in the tank. 

To test the efficiency of the process, I caused 174 pounds of sulphuretted ore, 
assaying $56.15 in gold, to be worked, and obtained 80 per cent. of the assay. Had 
the ore been properly crushed previous to roasting, the returns must have been larger. 
The powdered ore was of all degrees of fineness, from a fine powder toa gravel the 
size of coffee beans. Of course the latter were not desulphurized ; and that we should 
obtain 80 per cent. of the gold with such imperfect crushing was a matter of surprise. 
The cost of reduction at Gold Hill, N. C., the mill working 18 tons a day, and allow- 
ing one dollar per ton for wear and tear, is $3.274 per ton. 

GEORGE CLENDEN, JR. 


The results of twelve different trials with the same apparatus are also 
given in the prospectus. The sum total was 96 tons; the product was 
#1,629.29; the average value of the sampled assay, $17.69; and the pro- 
duct, 80 per cent. of the assay value. 


ALLUVIAL WASHINGS. 


In all gold-bearing countries it is common to resort to the hydraulic 
process for the extraction of the precious metal. Two circumstances 
have stood in the way of its use in New Hampshire, where it might serve 
an excellent purpose: first, the land in the Ammonoosuc field is valua- 
ble for farming purposes, and the farmers do not desire to have it torn 
up; second, there were operations of this nature upon Salmon Hole brook 
in Lisbon, in 1866, whose managers “salted” the sluice-boxes, and thus 
falsely obtained a large yield. There is no reason why a judiciously se- 
lected locality would not furnish profitable results, particularly in Pitts- 
burg, where the value of the land is but a trifle. 


28 ECONOMIC GEOLOGY, 


Hydraulic processes have been thoroughly perfected in California. 
Canals, many miles in length and passing over ravines 200 feet deep, 
have been constructed to convey the water, so that by a large hose-pipe 
it may be brought to bear upon the auriferous gravel in the right place. 
That gravel is commonly as hard as rock, the pebbles being too firmly set 
to be broken apart by hand. Detailed descriptions of the processes are 
unnecessary; but I will mention the cost of excavation in different parts 
of the country, as presented by several experts. Prof. W. P. Blake esti- 
tated, from work done in North Carolina in 1859, that earth containing 
only the twenty-fifth part of a grain of gold, or two mills’ worth in a 
bushel, will pay about two dollars a day to a single pipe. In California, 
about 1868, the same gentleman estimated that, with certain conven- 
iences described, 1,500 tons of earth could be removed in a day’s time 
with the labor of two men. This result has been actually obtained 
there under favorable circumstances. 

M. Laur, a French engineer, estimating miners’ wages at twenty francs 
($3.68) per day, found that the expense of manual labor necessary for 
working one cubic metre (38 inches) of gravel by the several methods to 
be the following: By the pan, about $13.80; by the rocker, about $3.68; 
by the long tom, about $0.92; by the sluice, about $0.31; by hydraulic 
washing, about $0.051. This would make the cost of a cubic yard about 
five cents. These estimates include the cost of the water. 

The cost of hydraulic mining in our state ought not to be greater than 
in California. These estimates do not cover the cost of the canals and 
apparatus, though they do include the rents paid for the water, or the 
interest upon the capital. The profit arising from the employment of the 
hydraulic processes must depend upon the richness of the gravel and the 
expense of uncovering the “pay dirt.” In Canada, as already stated, and 
in Vermont, the hydraulic methods have been employed successfully 


within the past dozen years. 
Can GoLp-MINING BE MADE PROFITABLE IN NEw HampsHIRE? 


We now possess the data needful to enable us to answer this question. 
After ten years’ intimate acquaintance with all that has been done in the 
way of mining and milling gold in our state, I am satisfied that this busi- 
ness, if properly conducted, cannot fail to be remunerative. This is not 


METALS AND THEIR ORES. 29 


true of any regions except the Ammonoosuc district, and the related 
rocks along the upper Ammonoosuc river and near the border of Can- 
ada. Several points of interest in this connection may be mentioned. 

First. It is not intended, when it is said the gold business ought to 
be remunerative, that a multitude of people can engage in it and become 
wealthy in a short period. A false impression prevails as to the nature 
of gold deposits. In California, persons have been fortunate enough to 
strike ‘‘pockets” of gold in the gravel containing many thousand dollars’ 
worth of metal. Those are the few and rare exceptions. Out of the 
hundreds of gold quartz mines wrought upon the Pacific side of the con- 
tinent, there are no instances of similar “finds.” The gold is obtained 
only through persevering, tiresome labor. Whatever will be obtained 
in our state, must come in the same way. No rich placer deposits have 
wer been discovered within our limits. Should any such be found, and 
the cost of their discovery be estimated, it will appear, as is the case with 
those in the West, that a fair proportion of labor has been expended for 
the result. 

Second. We must not expect to obtain profitable results in gold min- 
ing without the expenditure of considerable capital. This is like all other 
business pursuits. For example: a farmer must §$urchase land, build 
houses, barns, buy horses, cows, sheep, etc., procure implements of till- 
age, etc., before he can produce articles of merchandise. He may ex- 
pend, say, $6,000, which is his capital stock. He will not expect to real- 
ize from the sales of his produce the whole amount of his investment 
the first year. If he obtains produce worth one thousand dollars, he 
would do remarkably well. So in mining and milling gold, no one ought 
reasonably to expect to receive the first year a larger proportionate re- 
turn upon his investment than the farmer has received from his capital,— 
say 16 per cent. The nominal capital of the Dodge and Lisbon compa- 
nies is $123,000. During the ten years of their existence, $50,000 in 
gold has been obtained from them. This certainly represents more than 
the sum of actual payments in cash by the companies, and at the least 
showing would indicate a 4-per cent. annual dividend for the whole time. 

The question arises, What is the proper capital required to carry on 
successfully a single mining and milling establishment in New Hamp- 
shire? The first item is the cost of the land, by lease or fee simple. This 


30 ECONOMIC GEOLOGY. 


is a matter of special agreement between buyer and seller. I will assume 
that a section of the Dodge or Lisbon mine, 500 feet in length, or one of 
equal value elsewhere, may be obtained for $5,000. The cost of a mill- 
site depends upon the same considerations as that of the mine. Suppose 
the site and improvements, with buildings, to cost $8,000. The necessary 
machinery, such as that used most recently in Lisbon, can be put in by 
responsible parties for $2,500. Add $1,000 for opening the mine and 
various necessary expenses, and the amount of capital required, there- 
fore, for the establishment throughout, would be about £16,500. The 
working expenses may be determined by what has been paid already. In 
1875, the Lisbon company paid $1.50 per ton for mining, and $1 for the 
delivery of the rock at the mill. The Electro company, in 1874, paid for 
mining and culling $2 per ton, $1 for cartage, and $1.50 for milling. In 
1869, I stated that the cost of mining and cartage was about $4 to the 
ton, and the expense of milling about the same, or $8 in all. This was 
estimated in a depreciated currency, and before the art of mining was 
well understood in Lyman. I suppose the first two estimates do not 
include the cost of superintendence. 

Some of the best estimates of the cost of gold mills and of working 
them in California fre given in R. W. Raymond’s report on the Mixeral 
Resources west of the Rocky Mountains for 1872. The cost of a complete 
mill, including engine and boiler, is usually estimated at $1,000 per 
stamp. In a large mill of as many as 20 stamps, this includes the 
concentrating and chlorination works. The same authority presents a 
detailed account of the entire cost of milling, including interest on the 
cost, repayment of cost, and management. In a 30-stamp steam-mill, 
with a crushing capacity of 72 tons a day, this expense is $2.04 per ton, 
not including the cost of concentrating the tailings and chlorinating the 
concentrates. The last item would not be of much account when very 
few sulphurets are found. It would correspond to the expense of working 
the sulphurets, such as was incurred in the Crosby mill in Lyman. I 
understand the entire cost of that mill to have been $18,000, and to be 
capable of working 20.tons of ore per diem. Mr. Crosby estimated the 
entire expense of milling to be $5 per ton, and $2 additional for mining 
and delivery,—making $7 in all. 

Using these figures for a basis, and making allowances for apparatus 


METALS AND THEIR ORES, 31 


and superintendence, the following may express the proper capital and 
working expenses for extracting the gold from the two classes of ore 
occurring in New Hampshire: 


Quartz mining. Sulphurets. 
Cost of mine, . . : és . 3 . $5,000 $5,000 
Cost of mill, F : ; Fi ; ; - 10,500 18,000 
Opening the mine, : ‘ 5 3 . - 1,000 1,000 
Total capital, ‘ : 5 F : . $16,500 $24,000 

Running expenses. Quartz mining. Sulphurets. 
Mining and cartage, per ton, ‘ ‘ . $3.00 $3.00 
Milling, per ton, . . é i . z ‘ 2.00 5.00 
Superintendence, say— : : 3 : +10 Fo fe) 
$5.10 $8.10 


Should a company be formed to extract gold from the quartz or sulphu- 
rets, these figures express the capital absolutely necessary for the under- 
taking and the proper running expenses. Circumstances of various kinds 
might add to or diminish the amount of necessary capital; but there 
would not be much variation from the figures given for the running ex- 
penses. 

It is easy, from these figures, to estimate the income which might be 
obtained from a single enterprise of this nature. If the ore averaged as 
high as $19 per ton, as stated by Dr. Rae, the profit on each ton milled 
should be $14.90. Eight tons were carried through the whole process 
daily in 1875. That should afford a daily profit of $119.20. Supposing 
that the daily yield be practically $15, which was the case in the earlier 
workings, and allowing $10 per ton for the net income, we should have 
$80 as the daily return to the company, or $20,000 for the year of 250 
working days. These figures are indications of what the gold mining 
business might become in our state when properly and economically con- 
ducted. A larger capital, mills of greater capacity, and the reduction of 
a greater number of tons daily, by employing night labor, would add 
very much to the amount realized. I have not given the results obtained 
from working the sulphurets. Those given from essentially actual ex- 
perience are to be preferred ; and they will afford a method of estimating 
the possible merits of the gold mining and milling business. 


32 ECONOMIC GEOLOGY. 


SILVER. 


Several veins of galena afford valuable percentages of silver. The 
only one that has been milled is from Madison. According to Prof, 
Seely’s assay, this contains 94 ounces, 11 pennyweights, and 5 grains 
of silver to the ton of lead. This is the old Eaton mine described by 
Jackson. I understand, from the late H. J. Banks, the manager of the 
mine, that during his administration $55 per ton was obtained by actual 
sale for the silver contained in the ore. The mine itself will be de 
scribed under lead. 

Near the summit of the road over Gardner's mountain, in the south- 
west corner of Lyman, are veins of argentiferous galena, owned by J. H. 
Paddock, of St. Johnsbury, Vt., which have been exploited slightly, and 
are worthy of further attention. I examined them first in 1869. The 
earth and a little rock were removed, exposing a vein of clear pyrites 
and galena over four inches thick. This was traced for five or six rods, 
cutting the strata at an angle of 70°, the dip of the strata being 62° east- 
erly, and the vein 50° S. 20° E. In 1875 I found that additional excava- 
tion had uncovered the vein down to 16 inches in width, the principal 
portion being galena. Returns from the assay office show from $15 to 
$36 of silver to the ton. 

One of the first mines opened in Lyman showed both silver and gold 
in the galena. It is not worked for either of these metals at present. 
The property is a part of the Paddock company, and had. originally the 
name of the New Hampshire Silver Lead Company, with a nominal cap- 
ital of $500,000. From Prof. Wurtz’s reports upon this property, made 
in 1864, I have condensed the following statements: 


There are two groups of veins, called the West lodes and Orchard veins, the former 
cupreous, the latter of lead and silver. The west group consists of three ‘‘ heavy quartz 
outcrops,” one of them, Io feet wide, containing numerous strings and bunches of ga- 
lena, with copper pyrites, gossans, and honeycombed cavities, including ‘‘vugs,” or 
cavities lined with crystals of quartz, rarely containing indigo copper. It was traced 
300 or 400 yards in length. The schists adjacent are greatly stained and incrusted with 
limonite or iron ore, indicating a highly metalliferous condition for the country. 

The second, or Orchard group of veins, consists of two, each about two feet wide, 
and apparently true fissure veins, with the compass course N. 50° E. They contain 


METALS AND THEIR ORES. 33 


chiefly galena and zinc blende. The quartz is ‘‘comby,” carrying much gossan; and 
the walls, which near the surface are very rotten, become hard and quartzose several 
feet down, and well charged with iron pyrites. Several assays of the different galenas 
have been made by Dr. Torrey, and the results tabulated as follows. He supposes the 
galena to contain only 80 per cent. of pure lead, allowing for impurities; and the ton is 
taken at its full value of 2,240 pounds. 


Ounces | Ounces | Value of | Value of 
of of silver gold Total. 
silver. gold. in coin, | in cvin, 
In 1 ton of galena from 

West lode—dark........ccescescececasccatcesnscssengeees 581877 | seeesaurses! $7224 | seaewaxees $180.00 
se Tig Wits cerersravenncspgayaresanavsen aie ata rasintaearanalieritemeyerenacereiayete Ren 7EO: jl seretataeraents 46:28: lecomeccms| —ES4eGO 
Mean Of West Lode ii wraueniprw sedan weminieaaaiienemanieerens AS FOS). Voreeetizveisiste BO.2r - eyes wenn 167.00 
Orchard: Veit esas seessenatngenean semana cena n wees S85 51.027 0.9014 65.98 $18.63 192.50 
Mean of the threes cncesesinnasansatins dare auiensmesten 47-540 wNhacibedeteraee Gras |ewecesesi 175.50 


An adit has been driven 300 feet into the hill to drain the west lodes. 


Argentiferous galena has recently been discovered by Capt. F. Ben- 
nett, superintendent of the Paddock mines, at both the 6o- and 120-feet 
levels, and from the shaft to the end of the drift, a distance of some 60 
feet. It occurs continuously along the foot-wall of the copper beds in 
considerable amount. The best assays show the presence of 89 ounces 
of silver to the ton, worth $89.73 at present prices. The value of this 
discovery consists in the fact that all the silver and lead found will be 
put to the account of profit, as the copper will meet the expenses of 
mining. 

The Stevens copper mine in Bath has a vein of argentiferous galena 
upon it, separate from the copper, about 18 inches wide. It is said to 
carry fifty dollars’ worth of silver to the ton. I do not know of any 
other instances of silver in the Gardner Mountain range; but its impor- 
tance will lead the proprietors of the other mines to search for it. The 
facts stated about its occurrence are sufficient to justify further explora~ 
tion; and it will not be strange if the further developments would make 
the silver business more prominent than the copper mining. 

Farther east in Lyman, mention has already been made of galena in 
the gold mines. That from the Bedell mine is said to yield thirty-three 


dollars’ worth of silver to the ton. In the Dodge, Hartford, and Titus 
VOL. V. 5 


34 ECONOMIC GEOLOGY. 


properties it also occurs, but not extensively. It should always be saved, 
as it is argentiferous, if not auriferous also. Any of the lead ores in the 
state are likely toprove argentiferous. Such are at Warren, Shelburne, 
Hooksett, Rumney, and Woodstock, besides recently discovered outcrops 
in Madison. 

In this connection, I will present a brief sketch of the famous silver 
mine of Newburyport, Mass., just over the New Hampshire line. It was 
discovered in 1874. The high prices paid for lands in the neighborhood 
have excited the minds of many of the inhabitants of Rockingham 
county; and specimens of lead, pyrites, or mispickel found in that part 
of the state have been carefully preserved, and the ledges exploited. I 
have examined several openings in that county, as in Newmarket, Exeter, 
Epping, Fremont, and Raymond, but have not seen anything of value. 
The veins are of quartz, with a little pyritous ore, imbedded in one of 
the schistose formations. The Newburyport mine is in sienite; and 
therefore one would look for corresponding veins in the Exeter range 
rather than the Merrimack or Rockingham groups, as many have done. 
T looked over the Newmarket mine, and perceived that some galena had 
been taken from it, apparently not a great amount. A dry looking quartz, 
and considerable tourmaline like that occurring in Lebanon (see p. 104, 
Part IV), were also observed in the opening. The Exeter range is like 
the Newburyport rock, but parallel with it. 


Tue MerriMack SILverR MINE, oF NEWBURYPORT. 


From the reports of Prof. F. L. Vinton, made September 28, 1876, Dr. 
R. P. Stevens’s, made April 13, 1877, and the superintendent of the 
mine, Edgar Shaw, I glean the following points of interest. Facts about 
the history of its working, change of proprietorship, etc., are irrelevant 
to our purpose, and will not be mentioned. The country rock is our 
Exeter sienite. The ores occur in a vertical fissure-lode fully 200 feet 
wide, traced two miles in a north-east-south-west course, but not of uni- 
form thickness or value over this distance. The lode mass is compact 
trap with quartz, seams of indurated calcareous clay and selvages of 
softer clay, especially on the north-west wall. The ore band wrought lies 
near this north-west or foot-wall, and consists of argentiferous galena, 
accompanied by gray copper or tetrahedrite, with a gangue of quartz. 


METALS AND THEIR ORES. 35 


Heavy spar, fluor, pyrites, copper pyrites, and blende occur in small 
amount. For the depth of 60 feet, the galena constitutes a sheet averag- 
ing 12 inches wide. Below this level the ore is more crystalline; and the 
lode clearly discernible to the depth of 220 feet. There are five levels in 
the mine, and two shafts; and Prof. Vinton estimated that 40,000 gross 
tons of ore were actually in sight, which may be concentrated to 4,000 
tons of dressed ore worth $94 per ton. The ore in sight on the first 
level was 1,500 cubic yards, and 10,000 upon the fifth or lowest. Under- 
ground, the vein has been explored a distance of 400 feet. The best part 
of the ore is situated in a chimney, nearly vertical, but inclined south- 
west, and averaging a width of 100 feet on the several levels. 

Dr. Stevens mentions a mass of auriferous quartz parallel to the lead 
seam on the south-east side, varying in width from one yard at the 60- 
feet level to 5 feet at the 150-feet level and lower down. Working tests 
of the value of the quartz gave $11 of silver and $9 of gold to the ton. 
He also refers to the probable existence of a narrow seam of tetrahedrite 
continuous with the main galena belt. This mineral is exceedingly rich 
in silver, the maximum being $4,610.62 to the ton. The galenas average 
“about $60 to the ton, and have been the principal resource from which 
bullion has been obtained. 

The mine is well equipped with the necessary appliances for working, 
and smelting or reducing works are nearly or quite ready for use. The 
community have differed in opinion respecting the value of the property. 
It is obvious that heretofore the aim of the managers has been specula- 
tive. Most of the openings in the neighboring towns are of little value. 
We have the same rock in New Hampshire; and whenever indications 
are found similar to those manifested at Newburyport, exploration may 
lead to remunerative mining. 


Maps oF THE MINING REGION. 


Before beginning a description of the copper mines, I will call atten- 
tion to two maps. The first is a geological delineation of the Ammo- 
noosuc mining district, and is placed for convenience in the atlas, and 
referred to upon page 280 in Volume II. It is designed to embrace the 
final results of all our topographical, geological, and economic studies, pre- 
pared for the engraver and colored at the latest possible date. The scale 


36 ECONOMIC GEOLOGY. 


is about three fourths of a mile to the inch, and it is sufficiently large to 
show all important features. All the material at our command has been 
made use of, supplemented by a special survey made by Major John N. 
McClintock for us of the territory west of the Ammonoosuc river. The 
geological coloring is much the same as that on the general map, save 
that the representations of the auriferous conglomerate and copper belts 
have been added. When Volume II was written, it was not known that 
this band occurred east of Lisbon village. The modified drift is not dis- 
tinguished. 

The other map is a special survey of the Gardner Mountain copper 
district, prepared by J. N. McClintock. An error in the boundary line 
between Monroe and Lyman is my own. Contours for every ten feet 
are represented, and the outer edge of the wooded areas, It is designed 
to show the mineral proprietorship of the several tracts of land, both 
those valuable for ores contained, and the intervening farms. The col- 
ors show the shapes of the several tracts better than the lines alone. 
The following is a list of them, beginning at the north end, with their 
dimensions, and the nature of the minerals present: 


Name. Acres. Mineral. 
Gardner Mountain Company....cssseccsccectvectecaucertrees 250 Copper. 
Kinney: fatitty sciwisnavieanan seem apemenneuree reais nee henson 250 | Copper. 
Carter farm—scattered lots ........eeseeeecsenesecsecercenane 250 | Copper. 
Carter min eiasiazis cnrsieaie sia eicieiute i anbelveiaiels dieiesasoia Bis ra Sea aledenionnie zoo | Copper. 
Gregory Company eiais-viie/s sinrnidieiresioseieine: neinisceca niecainieronisiavesiainie ase 160 | Copper. 
Weerid all Lot isa siace:scsissasesainiosa siestpninyerasetipaionasaesececerasayoibioaeinjaiavese Senate too | Not explored. 
Penhallow® lot sis-sisinias:sieieininievieiewiereieminceislelsve-aaceierstein:eiaiehs eleivietivetas 300 | Not explored. 
Paddock Company: seieisisisis sgisisierainiessradese sicreie.csnre everaratete avetiarratica ore 1200 | Copper, lead, and silver. 
AD VEU S irasrciag ieteaieeisncteearere ionisints gape einer sreteainacnea ate apie ziaS 250 
Richards omg snacacsaecinseiniaiey sg ssivisisiceea ainsi wats ee balsielelaneeeye ae 250 
Abram Smithvon1naimeu tn seeunaa anes ete a aeeenceeeees 450 
Paddock: Silver: Lead issues eer easton ieae ele 3oo | Lead and silver. 
Haviland: Company nv e ticisiceisiv adisinie aves cisth 0800 08 nina d see biel 160 | Copper. 
MNO WTO ete scSeaises siaici ain wisieleiaieeujsioaaiaetoain teavacnsaainrdlardseineoiatasateienesuasveinds 120 | Copper. 
Stevens: Company vaisscece eoeiniacace\arcserespiareisisvarelecosnlevevareeiedetoimrvtetesnreoncayece 160 | Copper. 


The map delineates the original lots of Lyman township. Farther to 
the south, in Bath, are three or four additional openings for copper, the 


a 


=S 


S 
\us 
Ley ty 
Le Myf 
SS 
—S==>= = < = 
Se Ye~ 
gy ~<\ 
S thy \\W\ : 
SN = \\ . 
SS = yy \\ \ S = 


Ce 
) 


ae a 
=] 
i ie 
Cy S 
ss fae ™ 
Me ee 
iy sel 
= tae 
Sane \ 
fe Cd 
Wet = > 
Pa Sy: Ree 
eee a 
} CG ae ae WS 
ge 
Ag Se Db ) 
{i Ge BS FN 
‘ fay 


rege Kh? Te! 
(ge 9 
eee 4 


Me CLINTOCK. ~\ 


CRAFTON COUNTY 
NEW HAMPSHIRE 
G CAT! OF TH 
1876 


TOPOGRAPHICAL MAP 
BY JOHN 


SUMMITS AND BAST SLOPE OF 
CARDNER MOUNTA™™ 
BATH. MONROE, LYMAN anv LIT TLETO. 

COPPER MINING COMPANIES . 


TRAE 


—_6Y 


METALS AND THEIR ORES. 37 


last known as the Forsaith mine. The site of Paddock’s mill is also 


shown.* 


Copper. 


The region covered by these maps will first be considered. There are 
at least four belts of cupreous rocks situated upon and adjacent to Gard- 
ner mountain. Including some exposures in Waterford, the distance of 
the remotest openings from each other is 12 miles. The richest veins 
follow the mountain, and have been exploited principally upon the east 
side. The rocks have been described heretofore as the Lisbon and Ly- 
man divisions of the Upper Huronian, believed to correspond with the 
lower copper belt of Lake Superior in age. The former of these divi- 
sions consists mainly of our “greenstones”’ or chlorite schists, metamor- 
phic diorites, and diabases, with dolomites. The latter or Lyman seriés 
consists mainly of argillitic schists and slates passing into quartzites. 
Both these formations carry copper. I do not feel confident that the 
distinctions between these formations are well shown through Lyman 
and Monroe. The principal portion of the mountain range consists of 
the argillitic schist, agreeing in mineral composition with the ellas of 
Cornwall. They are altered clays, containing more or less silica, some- 
times passing into quartzites. The range to the east, represented by the 
Quint mine in Littleton, and that in Monroe, are connected with the chlo- 
ritic schists and diabases. The same series, with inferior copper seams, 
crops out in Lisbon, underlying the village. 

The same formations are developed in Quebec province about Sher- 
brooke, Ascot, Lennoxville, etc., where they are filled with copper veins. 
More openings have been made in this formation in Quebec than in Ly- 
man. A few of the mines there have turned out well, having been ope- 
rated profitably for the past twelve years. Logan referred these rocks to 
the altered Quebec group, a view adopted by us in our first annual report, 
but abandoned soon after. 

The ore of copper is chalcopyrite,—the common yellow sulphuret of 
iron and copper,—consisting of sulphur, 34.6; copper, 34.6; iron, 30.5= 


* The positions of all the known pits and openings for copper are indicated by a bright color. Upon some of the 
lots it is possible to observe six or seven of these openings upon veins parallel to one another. The accurate trac- 
ing out of these subordinate lines is a matter of great difficulty, and can hardly be stated with precision at present. 
Of the general arrangement and direction of the whole series, the map speaks plainly. 


38 ECONOMIC GEOLOGY. 


100. Excepting occasional blue and green carbonates and the black 
oxide, any other ores of copper are scarce in this region. The associ- 
ated ores are argentiferous galena, zinc blende, and an abundance of 
pyrrhotite, the last named frequently forming beds by itself with slight 
percentages of copper. All these ores may be auriferous, but to how 
great an extent remains to be proved. 

The veins are usually situated in broad belts of intermingled pyritifer- 
ous and siliceous layers, separated by elvans or diorites. The immediate 
veins may be one, two, or more feet wide, often so close together as to 
be practically from six to ten feet broad. The ore is in massive, not 
crystalline bunches, most abundant immediately contiguous to nodules 
of quartz. Several cases of small veins crossing the strata will be de- 
scribed in connection with individual mines. Our theory as to the origin 
of the deposits has been that they were originally beds, not fissure veins; 
and that in later periods the copper has been segregated from the gen- 
eral metalliferous belt into the several strings and veins making up the 
richest portions. These are found intersected by small cross veins of 
ore with scarcely any gangue, so that, as the country is exploited more 
and more, the evidences of the presence of the copper in so-called fissure- 
lodes increase. 

I have thought the continuity of the vein is to be seen in the 
presence of a series of lenticular patches or bonanzas, not succeeding 
each other on absolutely the same plane, but overlapping. On this view, 
what seems to be the same vein in adjacent lots is rather a series of 
flattened bunches, working more and more to one side. I have not yet 
discovered irregularities in the veins on Gardner mountain correspond- 
ing in magnitude with those of the auriferous conglomerate in the south- 
east part of the town, though only exploration is needed to develop them. 

I will now describe the features of the several mines in detail. 


Gardner Mountain Copper Company. This property consists of 250 acres of land , 
held in fee simple, a farm-house with the usual outbuildings, and the improvements 
effected for mining purposes. Much of the land has been cleared, a part remaining 
wooded. It has been known heretofore as the Albee mine, from its former owner, J. 
A. Albee. The principal outcrops are on a hill several hundred feet above the Con- 
necticut, sloping northerly. The eastern slope is precipitous. The veins are hence 
well situated for exploration by cross-cuts, or through a drift following the course of the 


METALS AND THEIR ORES, 39 


metalliferous rock. The rocks are mainly argillitic schists carrying bands of cupreous 
ores. There are three distinct metalliferous belts, divided by two greenstones (or 
sandstone, as called by the miners). Their character is indicated at the surface by 
yellowish-brown ferruginous stains. When these are dug into, iron or copper pyrites 
invariably show themselves. The most western of these belts is 178 feet wide, meas- 
uring from a point close by the shaft-house. A small opening upon this belt, several 
hundred feet to the south-west, shows copper. The middle belt is 87 feet wide. A 
shaft 78 feet deep is on its west side. It was not practicable to descend this opening 
at the time of my visit (October 5, 1877); but the piles of rock about the shaft-house 
reveal the nature of the materials brought up from the lowest depth. The vein matter 
is a mixture of slate and quartz, with bright yellow copper sulphuret conspicuously dis- 
seminated through it, in company with pyrites, or mundic, and a few crystals of anke- 
rite. The ore pile contains over 100 tons, showing well in copper. It was said that 
the whole width of the vein had not been disclosed at the bottom of the shaft. Near 
the copper ore are piles of compact pyrrhotite, somewhat cupreous and perhaps aurifer- 
ous, which came from the upper part of the opening. My report for 1869 made the 
following statement respecting this property, based upon observations upon this open- 
ing: ‘‘On Albee’s land several openings have been made, in one case 20 feet deep. 
There seems to be a sprinkling of copper in the schist for a width of 30 feet; and near 
the lower edge of the cupreous rock is a solid mass of iron and copper pyrites three 
feet wide, the former mineral preponderating. These features are promising for a good 
mine. The Cornish miners prefer to see the iron pyrites or ‘*mundic” very abundant 
at the surface, knowing by experience that the copper pyrites gradually takes its place 
according to the depth of the excavations. Our observation satisfies us that this rule 
holds as good in North America as in Cornwall.” A gentleman who descended the 
shaft recently told me that the copper-bearing vein varies in width from six inches to 
eight feet, and the ore differs in quality from 14 per cent. at the surface to 284 per cent. 
at the depth of 60 feet. To the south-east of the shaft are 150 feet of metalliferous 
schists, belonging to the eastern belt, extending from the eastern sandstone to the edge 
of a precipice. Two openings showing copper ore have been made in it,—the first, 25 
feet across it, and 5 or 6 in depth; the second, 6 or 7 feet long, 4o feet nearer the preci- 
pice. If these openings were connected, the whole distance would probably present 
the same cupreous color. These beds dip from 70°-75° S. 60°-70° E. 

Since my visit, the shaft has been sunk to 70 feet depth, and a new one commenced 
farther east and excavated 50 feet. The company consist of energetic capitalists from 
Portland, Me., and they propose to sink 150 feet further in the new locality. 

The Gregory Mine. This is situated in the eastern copper belt, upon a ridge 4,000 
feet easterly from the Gardner Mountain mine, and separated from the former by a 
valley 250-300 feet deep. In 1869 I made the following statements respecting it: 

“The only copper opening on the eastern belt in Littleton is at Mr. Little’s, near the 
town line. A shaft 184 feet deep has been sunk in the centre of a mass of copper- 
bearing schist 4o feet wide. The richest portion of this mass is a vein six or seven 


40 ECONOMIC GEOLOGY. 


inches wide, which at the bottom of the shaft has expanded to nearly three feet in 
average width. The general appearance of this property reminds one of the rock 
worked near Lennoxville, P. Q., on what is known as the Clark mine. On the Little 
estate the vein must extend for 150 rods, and the surface descends rapidly to the 
Connecticut river, so that a fine opportunity is here presented for the excavation of 
an adit along the course of the vein, which will both drain the shaft above and prove 
the value of the rock for a considerable distance.” 

In September, 1877, I found the mine in possession of gentlemen from Maine, who 
were at work sinking the same shaft I saw in 1869. It had then reached the depth of 
60 feet. Another shaft, 78 feet distant, has been sunk ‘in the barn to the depth of 53 
feet; anda drift has been started to connect them together, the space not excavated 
being only 16 feet. In the south shaft there is a drift northerly 25 feet at the depth of 
30 feet, and 18 feet to the south at the 25-feet level. At the bottom of this shaft a 
breadth of two feet contains much copper associated with quartz bunches. The rest of 
the space in the shaft has more or less of the ore scattered throughout. Neither wall 
was seen, the sinking having been prosecuted with the idea of reaching as great a depth 
as possible, without reference to its bounds. The large pieces brought out of the 
south shaft make the most brilliant specimens of any seen in the range, there being 
very little iron pyrites to lessen the bright yellow color. Large piles of ore are found 
in the barn and yard. One lot of twelve tons of seven per cent. ore has been sold from 
the barn shaft, and much remains there dressed to about the same proportion. There 
is no shaft-house except the barn, but a very good boarding-house for the miners. 
We traced the vein northerly upon the crest of the hill, the manifestation of it there 
consisting of pyritiferous schists. The width of the best part of this vein is thought to 
be six feet; and the two walls, when seen, consist of the homogeneous é« sandstone” 
of the country. The hoisting is dohe by horse-power; and there is considerable water 
in the mine. 

During the past winter, work has been continued. A drift has been driven 30 feet 
into the hanging wall, in order to determine the width of the vein. Ore was found 
sprinkled through the whole distance. 

Haviland Mine. This mine is situated on the Bath line, on the road from Lisbon to 
MclIndoes Falls over Gardner mountain. It embraces a tract of land amounting to 160 
acres, partly wooded and partly suitable for pasturage. The shaft-house is half a mile 
back from the highway. The argillitic schists usually dip about 70° S. 40° E. Narrow 
bands of diorite rock or ‘‘sandstone” are interspersed with pyritiferous schists. At 
the time of my visit, September 27, 1877, the shaft had been sunk 169 feet, sloping 
with the vein, steeper at the top than at the bottom. It is in a pyritiferous belt 200 
feet wide at the surface. At 70 feet is a short drift, where copper ore is disseminated 
through the schist. At 168 feet the rock has been cut 40 feet below the lower wall, and 
30 feet towards the hanging wall. Through this 70 feet of cutting, seams of cuprifer- 
ous mundic and copper sulphurets are constantly met with. There is a marked improve- 
ment over the surface rock in what has been brought up from the lowest depths. Four 


METALS AND THEIR ORES. 41 


veins cross this land,—one to the east, and two west from the shaft. Two or three 
other openings upon this land show more copper than at the shaft. This shaft has been 
sunk through the sandstone belt, which is 13 feet wide at 160 feet. The schists on the 
east are 100 feet wide before striking the next sandstone beyond, which is the most 
eastern copper belt. 

' During the winter of 1878 work has been continued, and the shaft is now down 200 
feet. At the 60 feet level isa drift of 30 feet; and at the 100 feet level is another 
drift 4o feet long. The mine is named from F. P. Haviland, of Waterville, Me. 

Stevens Mine. This lies near the north line of Bath, to the south of the Haviland. 
It contains 130’acres of tillage, pasturage, and woodland, and lies upon the southern 
slope of the Gardner mountain range. In coming from the Haviland mine the contour 
lines show a slight change in the direction of the mountain.. The mining improve- 
ments consist of a small boarding-house, shaft house with a shaft 100 feet deep 
(Sept. 26, 1877), cross cut 150 feet long at the bottom, and four other small openings 
in various places. 

The shaft follows down a band of cupreous schists several feet wide, the angle of 
descent being greatest at the top. Three prominent bands of copper ore are seen at 
the surface, gradually widening in the descent, each one being twelve inches, and solid 
at the bottom. Prof. Bartlett’s assay gives $37 worth of gold to the ton as coming 
from the pyrrhotite in these seams. There is a large pile of this ore outside of the 
shaft house. About 200 feet west is another vein showing copper ore along a breadth 
varying from two to eight feet, the gangue being white quartz with the mineral scat- 
tered through it, instead of cupreous argillitic schists, as in the first instance. This 
has been opened some ten or twelve feet in depth. There is a third vein about 150 
feet east of the shaft, which can easily be reached underground from the main shaft. 
A fourth vein occurs 400 feet east of the shaft. Thus three veins are reached by one 
shaft less than 400 feet apart. In April, 1878, I learn that the cross cut 100 feet deep 
has reached the vein to the west, and ore is being raised from it. The ‘silver vein” 
is an opening on the southern slope to the west of the copper excavations. There is 
here a trench 25-30 feet in length, displaying a vein of galena 18 inches wide. Sev- 
eral barrels of this ore have been taken out. It is said to contain, of silver, $50 to the 
ton. It is of value in the future development of the country in connection with the 
argentiferous veins at the Paddock lead and copper mines. An unusual feature of the 
Stevens property is the occurrence of numerous boulders of copper and iron pyrites on 
the south slope. By reference to the maps it will appear that the main ridge of the 
Gardner mountain is bent to the east as it passes into Bath, and diminishes in size. 
It is on that southern slope that these boulders occur, noticed even twenty-five years 
ago. Such stones have not been observed on the eastern slope of the mountain all 
through Lyman. While it is possible they may have been derived from the veins to 
the north, the laws of boulder distribution imply their derivation from some locality 
near at hand, perhaps not north of the Bath line. Their occurrence recalls the discov- 
ery of the valuable mines about Capleton, P. Q., from similar indications. The pres- 

VOL. v. 6 


42 ECONOMIC GEOLOGY, 


ence of cupreous boulders on a similar south slope led to a search for their source, and 
the vein was discovered quite near at hand, and proved to be richer than any others in 
the district. 

Paddock Company. This is the largest of all the copper companies, embracing 
partly in fee simple the entire land and partly the mineral rights upon four of the orig- 
inal lots of the town of Lyman, and therefore supposed to contain 1200 acres. The 
course of the veins is more than three miles in length, reaching from the Titus farm 
upon the south to an unoccupied tract called on our map the Penhallow lot. J. H. 
Paddock, Esq., of St. Johnsbury, Vt., is the principal proprietor, and the manager of 
the mine and mill. He has brought together several of the tracts known ten years ago 
as the Oro, Osgood, Osborn, New Hampshire Silver Lead Co., etc. What were form- 
erly the Oro and Osgood openings are now the No. 1 and No. 2 shafts of the Paddock 
mine. Concerning these two mines, I wrote as follows in 1869: 

‘¢The next is called the Osgood mine, embracing about 700 acres of the land on the 
east slope of Gardner’s mountain. I examined four or five openings. The first, near 
the south line, was ten feet deep, exhibiting five feet width of copper schists. The 
second shows a width of ten feet of copper schists. The third is a shaft thirty-five 
feet deep. Eighty feet below is a short tunnel eighty feet long, and designed to cut 
the vein. A large pile of good specimens of this copper may be seen near the shaft. 

«¢ The next north is the Oro mine. Here is a shaft sixty-five feet deep, a shaft 
house, easily seen from a great distance on account of its conspicuous position, two 
drifts fourteen and sixteen feet long, and a vein from four to seven feet wide, carrying 
more ore near the hanging than the foot wall. Sixty tons, part yielding 10.80, and 
part 9. per cent. of copper, have been shipped from the mine to Boston. There are 
one hundred and seventy-five acres of land connected with this property, and the vein 
is eighty-eight rods long.” 

I have visited the No. 1 shaft several times during the past nine years, watching with 
interest the progress indicated. Work has not been done continuously. It may be suffi- 
cient to mention the present [April, 1878] aspect of the excavation. All the laborers 
have been transferred to the No. 1 shaft for the purpose of developing that one more 
rapidly than if two were being exploited at the same time. Seven miners are at work 
under the superintendence of Capt. Francis Bennett, recently of the copper mines about 
Lenoxville, P. Q. The depth of the shaft is 170 feet. It follows the vein very nearly 
in its course. Extensive levels are situated at ten and twenty fathoms depth. Ore 
has been taken from one or both of these for a distance of 80 feet lengthwise of the 
vein. It has been proved that the vein is continuous for the distance of 80 feet, 
though not perfectly straight. There are two well-marked bendings exhibited, the 
arc of the curve pointing easterly, and these were seen to correspond with eastward 
thrusts of a dolomite band at the surface. These irregularities recall the similar varied 
courses of the auriferous conglomerate in the east part of the town (see map, page 296, 
Vol. II), though much less extensive. Without doubt the careful exploitation of 
Gardner’s mountain in years to come will reveal bends and fractures corresponding 


METALS AND THEIR ORES. 43 


with those in the east part of the town. There are other cross cuts in the No. 1 mine 
confirming the truth of the continuity oft he vein, and, by inference, its probable extent 
indefinitely in both directions. At present a large body of ore is in sight near the 
twenty fathoms level, and it is being rapidly brought to the surface. The good ore 
occupies a width of from four to six feet. Quite recently Capt. Bennett has discovered 
along the foot wall a vein of silver-lead, referred to above. This is more extensive 
and persistent at the twenty than at the ten fathoms level, being often ten inches in 
width, with the quartz gangue included. Zinc blende or black jack had been noticed 
before as an occasional product, but it is now found to accompany the galena, the 
latter increasing with the depth. The discovery is of great importance, as it may 
lead to the development of silver mining along the mountain. The copper vein 
is composed of grayish-white quartz, much harder than the greenish schists adjacent. 
Similar veins occur in the other mining properties on the range, some of which may 
be the continuation of this. The map shows at least six parallel veins upon this 
property. One is characterized by the grayish-white quartz present; another exhibits 
more of a slaty aspect, as at No. 2; a third is a mass of pyrrhotite. The others are 
intermediate in character between the first two mentioned. The third is known as the 
mundic vein, and has been followed for more than a mile along the east foot of the 
mountains. It is slightly cupreous, and may prove to be richly so at a considerable 
depth, if it resembles similar veins in other metalliferous districts. The amount of ore 
produced from the No. 1 shaft previous to 1874 is thought to have amounted to 300 tons. 
Much more than that has been taken out since; but I understand the aim has been to 
develop the mine, to learn the extent of the veins, rather than to raise a large amount 
of ore. A road has been built to connect both the shafts with the mill, a mile and 
a half distant. 

At the No. 2 shaft the adit is now go feet long, and the veins at the surface over- 
head have been extensively uncovered. A most interesting feature is the existence of 
a small cross vein, cutting the strata two feet wide where thickest, and uncovered for 
eighty feet up the mountain. It contains more copper than the regular vein. Possibly 
it may extend to join a vein about 170 feet further up the mountain, and but slightly 
exploited. This and the galena vein on top of the mountain are the only cross veins 
yet discovered, but as time progresses others will be discovered much larger and more 
important than these. From these, we may conclude that these copper beds are 
properly fissure lodes, though so commonly conformable to the stratification, and 
therefore more highly esteemed. At one visit I saw about 150 tons of dressed ore near 
the mouth of the adit thought to average 6 per cent. of copper present. It was found 
that this ore would roast much more quickly than that occurring in the Vermont mines, 
as at Vershire and Strafford. They differ also in containing an excess of silica rather 
than iron. For similar reasons, one accustomed to estimate the percentage of copper 
in the Vermont ores will be inclined to undervalue the worth of the New Hampshire 
product. 


Concentration of Ores. It may be well to anticipate the proper order 


44 ECONOMIC GEOLOGY. 


of description, and mention the contrivances employed by Mr. Paddock 
to reduce the bulk of the copper ores while increasing their value. It is 
of no use to send to market lean ores, because.of the expense of trans- 
porting worthless rock. Hence various methods are in use to concen- 
trate them. The oldest method is to pick out the best pieces and throw 
away the poorer‘ones. In this way these ores may be easily brought to 
8 or 10 per cent. valuation. When the metal is very abundant, another 
process reduces the ores in a furnace by smelting to a matt of 40 or 60 
per cent. copper, and thus saves a great deal in transportation. Another 
method, well adapted to the New Hampshire ore, is to remove the copper 
by a wet process of extraction. This will be mentioned soon in detail. 
Still another plan has been adopted by Mr. Paddock. The ore is pulver- 
ized, and the copper ore separated from the lighter worthless rock by 
virtue of its greater weight. Wet and dry jigs are used for this pur- 
pose, and the results appear to be satisfactory. The ores are concen- 
trated to 15 or 20 per cent. in this way, very cheaply, and are in excellent 
condition for smelting. 

To carry on this business a mill is required, estimated to cost, with all 
the apparatus, if set up new, about $17,000. There must be an engine, 
a crusher, apparatus for elevating the crushed rock to an upper chamber 
where sieves may classify the material into several sizes, and the dry 
and wet jigs. I will briefly describe the process as it is being carried 
on at the mill in Lyman. An engine is at work driving a rock-crusher, 
elevating the powdered rock, shaking both jigs, drying the wet products, 
and for other purposes. It requires the services of one person to keep 
the engine in order, and a second to furnish rock for the crusher. In the 
upper chamber are sieves separating the pulverized rock into five parts ; 
first, the coarser pieces, which are made automatically to descend to the 
wet jig in the basement; second, three grades of coarseness, suitable for 
the Chubb concentrator, or dry jig; lastly, the slums or dust, which is 
too fine to be separated by either of the jigs. No attendance is required 
to separate these different grades and carry them to their proper places ; 
the business is attended to by machinery. The Chubb separator is a 
patented contrivance, making use of intermittent air puffs to classify the 
material into three parts; first, the ore concentrated to its utmost extent; 
second, the worthless material fit only to be thrown away; and third, 


METALS AND THEIR ORES. 45 


the middlings, a mixture of the other two kinds, which is made to go 
through the machine a second time. Without technical description, this 
apparatus may be styled a trough about 4 by 2 feet, placed over a bellows 
blowing 300 to 500 times a minute, according to circumstances. The air 
is forced through a perforated metallic plate, and the box is at the same 
time skaken. By these means the pulverized ore is separated into the 
three kinds of powder mentioned, according to relative weight, and grad- 
ually slides to the lower part of the boxes, the separation being facili- 
tated by a slight inclination and the presence of diagonal partitions of 
metal strips. An attendant watches the delivery of the product into 
boxes, properly separating the three kinds with the assistance of mova- 
ble partitions. One person can easily attend to the three machines 
employed in the mill, and perhaps as many as five. It is his business 
also to remove the boxes receiving the finished products as often as 
necessary, put the ore into the barrels provided for it, the refuse into its 
place, and the middlings back into hoppers. Meanwhile, another person 
in the basement watches the wet jig, where large sieves filled with the 
coarser rock are jigged underneath water, and the heavier parts sink to 
the bottom. In a short time the worthless material is thrown away, the 
heaviest put upon a steam-heated table and dried, preliminary to package 
in barrels for transportation, and the middlings saved for another wash- 
ing. I have examined the tailings left from both kinds of jigs, and 
observe that scarcely any ore escapes. Both processes separate the ore 
very carefully, and the waste is only slight. One grade of the ore re- 
mains,—the dust or slums. At present this is preserved for experi- 
ment, as the best method of saving the copper ore in it has not been 
perfected. Tossing in water is recommended, and will perhaps be the 
most convenient method of separation. It seems to me that a wet chem- 
ical process might be used to good advantage, such as will be described 
presently. 

I have been greatly pleased with the results obtained practically by 
this mill, and think that the processes employed will enable our mining 
companies to utilize their poorer ores to better advantage than before, 
I understand that the Chubb patent embodies peculiarities not existing 
in any other separator, and is better adapted than any other machine for 
this class of ore. It has been in use many months in Lyman, and has 


46 ECONOMIC GEOLOGY. 


successfully treated as much as 100 or 200 tons of ore, so that its value 
has been well tested. In case it should be taken for new localities, it is 
recommended that it be placed at the mouth of the mine, and thus save 
any unnecessary transportation of the ore before concentration, and the 
steam-power could also be utilized for hoisting purposes. 


Quint Mine. A mile or two east of the Gregory is the Quint or White Mountain 
copper mine, in Littleton. No copper property in this region had been so thoroughly 
explored as this in 1869; several buildings have been erected for shaft-house, whim, 
dressing-sheds, etc., and the main shaft has been sunk to the depth of one hundred 
feet. It was impossible for me to examine the character of the rock below the surface, 
as all the excavations were filled with water; but, judging from external appearances, 
the vein must be from six to eight feet wide, composed of white quartz with copper 
sulphuret, iron pyrites, chlorite, and ankerite disseminated abundantly through it. On 
account of the contrast in colors, very beautiful hand specimens may be obtained here. 
The location is a poor one, so far as drainage is concerned. 

Other Properties. There are many other farms where copper has been found, and, 
in some cases, extensively opened.. There were three examined north of the No. 1 
shaft of the Paddock company in 1869, known as the Stevens and Nason, Locke, 
Swan and Garland, and now belonging to Mr. Paddock. All of them showed excava- 
tions a few feet in depth, a mixture of the usual iron and copper pyrites in the schists 
several feet wide. 

Dr. Jackson examined copper upon Lang’s property in Bath, adjoining the Stevens 
mine. From his reports I condense the following facts: Two veins occur crossing at 
right angles, north-east and north-west courses. One of them is from one foot to 
eighteen inches wide, the other thicker. A detached block of pure ore, two and a 
half feet in diameter, was found in the meadow. A single blast afforded 100 pounds of 
20 per cent. ore. 

Farther south, as shown on the map, are three other copper locations. The most 
southern on the crest of the mountain is called the Forsaith mine, containing 140 
acres, showing quite a number of small openings, all of them showing copper ore. 

There are several openings in Monroe, on the west side of Gardner’s mountain. 
I have presumed the copper belt is repeated here, and the cupreous schists occur in 
many places, though comparatively little work has been done. The largest opening 
is upon the Bald ledge, operated several years since by Mr. Paddock. The best part 
of the copper schist is six feet wide, containing, in addition to the usual minerals, 
zinc blende and obliquely crossing veins of quartz. The shaft-house is very high up, 
so that the vein could be well drained to a considerable depth. The shaft was sunk 
to the depth of 80 feet. Ten tons of Io per cent. ore were the result of this exploita- 
tion. Farther west, down the hill, is another vein, possibly connected synclinally with 
the ore high up. 


METALS AND THEIR ORES. 47 


In Littleton and Dalton are two openings, showing the purple and gray ores of cop- 
per. One is on Wheeler hill, and the other is known as the Dalton mine, where work 
has been performed under the direction of J. B. Sumner, Esq. The rock of the coun- 
try is clay slate, but the gangue of the vein is a species of talcose schist, containing a 
little yellow copper and minute particles of magnetic iron. The walls of the Dalton 
mine are very distinct, about sixteen feet apart. The gangue is traversed by cross 
veins of quartz, often carrying fine specimens of the purple ore, or Bormite. A shaft 
has been sunk about twenty-five feet deep upon the vein, and a few openings have 
been made as far as 200 or 300 feet north of the shaft-house, sufficiently to prove the 
continuation of the vein. Similar proof exists of the presence of copper, perhaps the. 
same vein, half a mile in the other direction. This property is upon the top ofa hill. 
It is conveniently situated with reference to water-power, being near the Connecticut 
and one of its tributaries, so that the ore taken from the mine could very easily be 
concentrated at slight expense. An average sample of the whole vein sent by Mr. 
Sumner gave to Prof. Seely 5.4 per cent. of metallic copper. 


Copper in Milan. Similar ores to those of Gardner mountain have 
been discovered lately in Milan. The formation is the same. I have 
examined several openings. First is that of Nathan Fogg, a short dis- 
tance east of the Grand Trunk Railway. The vein dips 70° N.W. A 
pit has been sunk in it about fifteen feet, close by a small brook, and the 
ore shows well for a width of thirteen feet. It is a massive mixture of 
copper and iron pyrites, with galena and blende, without much gangue. 
A fair average gave C. W. Kempton 5.3 per cent. of copper. Immedi- 
ately adjacent to the foot wall is a pretty string of argentiferous galena, 
half an inch wide. The upper part of the vein also shows much galena 
and bright bunches of copper. An assay of the average under my 
supervision yielded a trace of gold and 2.65 ounces of silver to the ton. 
Excavations prove the continuation of the vein for at least 200 feet, and 
in one place there is a width of 40 feet of pyritiferous schists connected 
with the vein. The situation is very convenient to railroad transporta- 
tion. 

On the hill west, Mr. Nay has opened a seam running north-west, 
though tending to take the north-east course of the strata, which con- 
tains argentiferous galena. Mr. Nay has uncovered the rock in several 
places, but had not proved the value of the property at the time of my 
visit in August, 1877. 

On Hodgdon’s land, to the north, is the Twitchell and Mason mine. 


48 ECONOMIC GEOLOGY. 


They have cut into pyritiferous schists, sinking upon a vein six feet 
’ wide, richer than the usual mass of 40 feet thickness. Many bunches of 
copper were taken out, and I understand from F. L. Bartlett, of Portland, 
that nickel is present in the ore. 

On Cate’s hill, in Berlin, is a vein showing the minerals pyrite, chalco- 
pyrite, bornite, magnetite, hornblende, and tremolite. The ores are 
sparsely disseminated. 

This region promises well to the explorer, and it will doubtless be 
heard from in the future. Our map shows that the rocks continue here 
from the Ammonoosuc district, though interrupted by intrusive por- 
phyries. 


Tur Warren MINE. 


In the gneiss of Warren there is a bed of tremolite more than fifty 
feet wide, in connection with which is a vein of copper and zinc. Mica 
schist, dipping 45° N. 50° E., encloses the bed. Veins of pure copper ore 
with reticulations of quartz abound in the hanging wall, and a bed of the 
same material occurs along the line of the junction of the tremolite and 
schist. Veins of the copper, bunches of iron pyrites, and a resplendent 
black blende occur also in the midst of the tremolite, as well as a little 
rutile. Most of the tremolite carries copper pyrites, and the rock must be 
stamped and washed to allow of separation. The annexed plan shows 


Fig. 7.—PLAN OF THE WARREN MINE. 


a, Quartz; b, Ore vein; c, Trap. 


the mutual relations of the three trap dykes, veins of quartz, and the ore 
vein. It was prepared by Mr. Huntington, and is not drawn to a scale. 


METALS AND THEIR ORES. 49 


Considerable work has been done upon this property since 1840. The 
tremolite does not occur with the copper at great depths. Latterly the 
zinc predominates, and there is a little galena. At the time of my visit 
the mine was full of water, and I could learn little in addition to what 
has been presented. I made the following statements respecting it in 
1869: 


The Warren zinc mine is now under the management of Capt. Edgar. It has been 
known for twenty years as a copper mine, but as the vein has been followed down- 
wards the zinc has to a considerable extent increased at the expense of the copper, 
and it is for the zinc chiefly that the mine is now wrought. The principal vein is of 
quartz, ten feet wide, crossed by a mass of the mineral tremolite. The hanging wall 
is a sandstone, the foot wall micaceous slate. To the depth of twenty-five feet, copper 
ore and galena predominated. Below that point, to the bottom of the excavation, one 
hundred and fifty feet, the zinc is the most abundant, amounting to one half. At the 
bottom the vein is twenty feet wide, and there is a drift one hundred and eighty feet 
in length. There seems to be a ‘‘ pipe” or {‘ chimney” of pure ore in the vein, some- 
times fifteen feet thick and twenty broad, which is the most valuable part of the me- 
tallic sheet. It does not proceed on the direct line of the dip, but passes down about 
ten degrees from it. 

At present (1869) the ore is first sent to the Lowell Bleachery Company, Mass., 
where the sulphur is removed and converted into sulphuric acid. The residue then 
goes to Bethlehem, Pa., where it is smelted into spelter. 


Since 1870 the mine has not been worked. It is owned by Horace 
Brooks, of Franconia. 


Copper MINEs IN SOUTHERN New HAMPSHIRE. 


Within a few years a new impulse has been given to mining for pyrites, 
on account of the sulphur contained in it, for the manufacture of sul- 
phuric acid. This is used in bleaching, fabrication of artificial fertilizers, 
and a hundred other ways. Quite recently, chemical works for the util- 
ization of sulphur have been established about the principal cities, and 
there is a great call for the ores containing sulphur. By the burning of 
the ore,—a sulphuret of iron,—the sulphur takes oxygen from the air, 
-becoming sulphurous acid. This is condensed in water in leaden cham- 
bers, where an additional atom of oxygen is added, and the resulting 
compound is sulphuric acid. One of the principal sources of this pyrites 

VOL. V. 7 


50 ECONOMIC GEOLOGY. 


is Strafford, Vt., where copperas has been manufactured for the past fifty 
years. From that single locality on Copperas hill, thousands of tons of 
ore have been sent to market. The species is pyrrhotite, containing 39.5 
per cent. of sulphur, and is therefore less valuable than common pyrites, 
which has 53.3 per cent. of sulphur. 

There are several veins of pyrites in New Hampshire that can be 
successfully mined for the manufacturing establishments, especially as 
copper is usually associated with them. These veins are also nearer the 
market than those of Vermont, which are now mined so largely. Perhaps 
the most important of these is in the south-west part of Croydon. This 
has been visited twice,—in June, 1869, and May, 1870. The results of 
our examination are briefly these: The rock is micaceous and gneissic, 
one of the sub-divisions of the White Mountain series probably. It is 
elevated two or three hundred feet, on the south-east flank of Croydon 
mountain. Higher up is the quartzite, dipping at a high angle to N. 65° 
W. It probably overlies the sulphuret schist unconformably, as it cer- 
tainly does three miles farther north, the latter dipping 80° W. 10° S, 
@ne or two hundred feet east of the vein is a white gneissic rock, carry- 
ing an unusual amount of mica. This is parallel with it, and may be 
used as a guide in tracing it through the country. In this way the vein 
was followed for three fourths of a mile to the north, and from what was 
said to us, it is judged to extend equally far to the south. The vein has 
been opened to the depth of twenty-five feet. It was full of water at our 
first visit, but was drained at the second visit by means of a syphon. 
The vein mass is uniform in its width and composition. Next the hang- 
ing wall is six inches width of slaty layers, holding both copper and iron 
pyrites. Next succeeds two feet thickness of magnetic pyrites, or pyr- 
rhotite, very compact, solid, and nearly pure. There is no foreign min- 
eral present except small nodules of quartz. Next follows one foot ten 
inches of the same, less compact. Fourthly, is two feet thickness of 
gangue of quartz, or a micaceous mass carrying a large proportion of 
copper pyrites and zincblende. Below all this is a slaty mass three or 
four feet in thickness, similar to the upper layer, carrying considerable 
pyrites, which possibly may be utilized. The second, third, and fourth 
of these layers are valuable, and united amount to six feet in thickness. 
By Prof. Seely’s determination, the sulphur in No. 2 amounts to 37.68 


METALS AND THEIR ORES. 51 


per cent.; in No. 3, to 38.10 per cent.; and in No. 4, to 19.35 per cent. 
No. 4 also contains 3.17 of copper and 16.62 per cent. of zinc. 

On examining the veins to the north the sulphurets are found cropping 
out on the. surface for one or two hundred feet, and the vein itself can be 
traced on the property nearly to a house eighty rods distant. Further 
tracing was not attempted in that direction. It is common for this vein 
to be cut by irregular veins of white quartz. 

The outcrops are on a steep hill, perhaps three hundred feet above a 
comparatively level tract. Thus the vein could be easily drained, 
whether an adit be driven into the hill at right angles to the vein, or 
from the north and driven in on the vein itself. This site is less than 
three miles in a gently ascending country from Northville (Newport), on 
the Concord & Claremont Railroad. 

Neal Mine. Next in value is the Neal mine in Unity. This has been 
visited three times. It is owned by the Neal family, and is about four 
miles from North Charlestown. The vein has been described in Dr. 
Jackson’s report. It is a mixture of iron and copper pyrites, nearly three 
feet wide, and has been traced fully 2,200 feet in length. Drainage can 
be effected to the depth of seventy feet. The vein dips 78° W. 10° N. 
It has the same geological position with the Croydon mine, lying near 
the western border of the gneiss, and if the ores were mixed it would be 
difficult to distinguish many of the varieties from each other. It is 
probable that the ore would all become copper pyrites at 100 feet or 
more below the surface. 

There are other interesting veins on this property, but it is only suffi- 
cient for our present purpose to say that the pyrites can be as profitably 
mined for sulphur here as at Croydon, and if copper or other valuable 
metals should be ultimately discovered in abundance, it might be 
wrought for them also. 


Other veins carrying considerable amounts of pyrites, which are all worthy of ex- 
ploration with the hope of successful results, are the King property, upon C. Houston’s 
land, in the south-east part of Hanover; the land of J. W. Cleaveland, of East Leba- 
non, in the north-west part of Enfield; in the south-west part of Lebanon; Dr. Hub- 
bard’s mine on the Jackson farm, in the south part of Claremont. On account of the 
great value of this ore in the manufacture of fertilizers, it is to be hoped that these 
veins will be thoroughly explored, the market well supplied with sulphuric acid, and 


52 ECONOMIC GEOLOGY. 


thus both the mining district be benefited and the prices of the phosphates be reduced, 
and the whole community reap the advantages of lower prices of fertilizers. 


Tue Hunt anv Dovuctass PrRocEss. 


Other localities of copper are numerous, especially in the Connecticut 
valley, as in Haverhill, Orford, and Lyme. These and others are men- 
tioned in the catalogue of mineral localities in Part IV. Some of them 
may prove valuable as mines after exploitation, especially one on the 
west flank of the hill between Mts. Cuba and Smart. 

Copper is reduced at West Fairlee, Vt., by smelting. The ores of east- 
ern Vermont and those in New Hampshire south of Woodsville, belong 
to a different formation from those mentioned in the Ammonoosuc dis- 
trict,—the Coés instead of the Huronian. Some authors, especially the 
managers of mining companies, inform the public of their identity. But 
an examination of the rocks associated with the two will show that our 
copper veins belong to at least three distinct periods. Our ores are usu- 
ally low grade, and hence can be easily reduced by a wet process cheaper 
than by smelting. Having investigated the merits of the Hunt and Doug- 
lass process, I think it one well fitted to reduce our ores, and herewith 
present a brief notice of it, compiled from an authoritative sketch in the 
Mineral Resources west of the Rocky Mountains, for 1876: 


This is what is technically called a wet method, because the copper is removed from 
its ores in a dissolved state, the solvent employed in the present process being a 
watery solution of neutral proto-chloride of iron and common salt. Most oxidized 
compounds of copper,—whether obtained artificially by roasting sulphuretted ores, or 
found in nature in the form of carbonates and oxides,—when digested with such a 
solution are converted into a mixture of proto-chloride of copper, which are dissolved, 
while the iron of the solvent separates in the form of insoluble hydrous peroxide of 
iron. When the solution of chlarides of copper thus obtained is brought in contact 
with metallic iron, the copper is separated in a metallic crystalline state, while the 
iron passes into solution, reproducing the proto-chloride of iron, thus restoring its sol- 
vent powers to the liquid, which we shall call «‘ the bath,” and fitting it for the treat- 
ment of a fresh portion of copper ore. This process of solution and precipitation can, 
under proper conditions, be repeated indefinitely with the same bath, the only reagent 
consumed being the metallic iron. 

The chief advantages which wet processes possess over smelting lies in the economy 
of fuel. To extract copper from a low grade ore by smelting, five or six furnace opera- 
tions are necessary, and about one ton of coal is consumed for each ton of ore treated ; 
while for the various wet processes, a single calcination, in which not more than 300 


METALS AND THEIR ORES. 53 


weight of coal is consumed for each ton of ore, is the only furnace operation required 
to obtain the metallic copper in a precipitated form known as cement copper. An im- 
portant item of cost in wet processes is the metallic iron employed to separate the me- 
tallic copper from its solutions. The same amount of iron is required to precipitate a 
ton of copper, whether extracted from a poor or a rich ore; but as for the smelting of 
the latter much less fuel is required, it follows that rich ores are generally treated by 
smelting rather than in the wet way, any saving of fuel in the latter being more than 
compensated for by the cost of iron. No general rule, however, can be laid down to 
determine what grade of ore can be more profitably treated by one method or the 
other, inasmuch as circumstances of locality, affecting the cost of fuel and the price of 
iron, must in each case be taken into account. 

The various other wet methods of copper extraction may be divided into two classes: 
those in which the previously oxidized ore is treated with hydrochloric or sulphuric 
acid to dissolve the oxide of copper, and those in which sulphuretted ore, generally 
after a preliminary roasting, is calcined with an admixture of sea-salt or sulphate of 
soda, by which the copper is converted into chloride or into sulphate. All of these 
methods, when properly applied, effect a pretty thorough extraction of the copper; but 
the cost of the reagents which have to be added to every charge of ore precludes alto- 
gether the use of some of these methods, except in certain favored localities, and ren- 
ders them in almost all cases, it is believed, less economical than the present one with 
the Hunt and Douglass bath, for which the following advantages are claimed: 

I. It is a general method adapted to all compounds of copper, while that by calcina- 
tion with salt is only applicable to sulphuretted ores. 

II. It does not require the addition of reagents, such as acids, salt, or sulphate of 
soda, to each charge of ore, since in the regular course of the operation the solvent 
required for the treatment of the ore is constantly reproduced. 

III. The bath employed being neutral, certain impurities of the ores, such as arsenic, 
which passes into solution and contaminates the product in the wet processes, remain 
undissolved, so that a purer copper is obtained. 

IV. There is no unnecessary waste or consumption of metallic iron. 

Ores reached by this process. First, may be included the various sulphuretted ores, 
as copper pyrites (often mixed with iron pyrites) and the variegated and vitreous sul- 
phurets, all of which are readily oxidized by calcination. Second, are the oxidized 
compounds of copper, such as the red and black oxides, the green and blue carbonates, 
and salts, like the oxy-chloride and silicates like chrysocolla. Third, are the deposits 
of native or metallic copper, which in almost all instances are most advantageously 
treated by mechanical means. The presence of carbonate of lime or magnesia is ob- 
jectionable, since it decomposes the proto-chloride of copper, and thus indirectly pre- 
cipitates the iron from the bath. The action of oxides of lead and zinc, which come 
from the roasting of blende and galena when these are present in the ore, produces a 
similar effect. When not too abundant, the effect of all these substances may be cor- 
rected by careful roasting. 


54 ECONOMIC GEOLOGY. 


Practical workings. This process was first worked continuously for a year at the 
Davidson mine in North Carolina. The ore, a pyritous copper ina slaty gangue, was 
dressed up to 5 or 6 per cent., crushed, roasted so as to contain about one fourth of its 
copper as sulphate, and treated in stirring-vats in charges of 3,000 pounds. The loss 
of copper was from .3 to .5 per cent.; and the bath maintained its strength in chloride 
of iron without the use of copperas or sulphurous acid. The amount of iron consumed 
was equal to 70 per cent., and the salt to 25 per cent., of the copper produced. The 
entire cost of producing cement copper from the dressed ore of 53 per cent. was esti- 
mated at 33 cents per pound. 

Next, six calcining furnaces for the treatment of twelve tons of pryitous ore daily 
were erected by the same proprietors at the Ore Knob mine in the same state. Up to 
January 1, 1875, over 200 tons of copper had been made there by this process. The 
cost of mining, making the copper, and all expenses, amounted to 8 cents per pound. 
These works were soon after enlarged to nearly three times their former capacity; but, 
in sinking below the water-line in the mine, the ore, hitherto free from lime, was found 
to contain 30 per cent. of carbonate of lime. This rendered it necessary to concen- 
trate the ore by crushing and washing,—works for which have been erected. 

At Phenixville, Penn., two sorts of copper ores are being treated by this process,— 
the one a magnetic iron containing about 3 per cent. of copper, the other a hydrated 
silicate. One ton of the first and four fifths of a ton of the second are now daily suc- 
cessfully treated at this locality. 


The cost of the plant, or buildings and machinery required for the 
working of the process, is from $12,000 to $15,000. The details are 
given in the annexed letter from Dr. Hunt: 


LETTER FROM Dr. Hunt. 


As you desired, I write you some notes as to our copper process, its cost and its ad- 
vantages, compared with smelting or shipping ores, considered from the point of view 
of New Hampshire copper mines. I give, first, the cost of treating in a small work 12 
tons of 2,000 pounds daily, and suppose the ore to yield 8 per cent. of copper, labor to 
be $1.25 a day, and wood $4 a cord: 


For grinding (steam power), 14 cords, . - $6.00 
Labor of 3 men, at $1.25, . : i » 3.75 
For roasting, 4 cords, ‘ ‘ ® < - 16.00 
Labor of 12 men, . a 5 é ‘ + 15.00 
Tank-house, 2 men, ‘ : : ‘ « 2.50 
Superintendent and chemist, . “ ‘ + 5.00 
Scrap-iron, 1,300 pounds, at 14. cents, . - 19.60 
Three hundred pounds salt, and sundries, “A625 


$72.00—=$6 for 2,000 lbs. ore. 


METALS AND THEIR ORES. 55 


The cost of plant for the above, including a 32-horse-power engine, 4 furnaces, 21 
” tanks, and 2 pairs of rolls and buildings, has been, at Phenixville, $12,000. 

To compare the above with shipping ore from Strafford to Boston. Let us suppose 
hauling and handling to station, $2; freight on railroad, $4.40=$6.40 per ton (the 
smelter’s ton is 2,352 pounds). The wet assay of the ore is 8 3-ro per cent. copper, 
from which he deducts, according to custom, 1 3-10 cents, leaving 7 per cent. to be 
paid for at the present rates of $3.75 per unit. 


Io gross or smelters’ tons (23,520 pounds) of 7 per cent. ore at 
the above price will bring . : , ‘ ‘ . $262.50 


Deduct for freight at $6.40 per ton, 3 . 7 : : 64.00* 
$198.50 


The above amount of ore equals 11 net tons of ore at 8 3-10 per cent., in treating 
which in the moist way the loss will not be over 5-10 per cent., leaving 7 8-10 per cent. 
of copper to be accounted for, or 1,833 pounds. This, as cement copper, will sell for 
21 cents when ore brings $3.75 per unit, equal to $384.93. But the treatment of the 
ore, as we have seen above, costs $6 the ton=$70.50, to which, for packages and 
freight to Boston, we may add $7=$77.50. 


Deducting this from $384.93, we have for net return from the 
ore treated by the Hunt & Douglass process, : si 3 $307.45 


For the ore shipped as above, ‘ j ‘ 5 a ‘ 198.40 
$109. 50* 


To this we must add the consideration that the selection of ores of 8 3-10 per cent. 
for shipment involves a considerable loss, and that with rocks on the spot it would be 
advantageous to treat ores of much lower grade got with less labor in dressing. De- 
ducting from the estimate above the cost of iron, which varies with the richness of the 
ore, we have for 12 tons $52.50——$4.38 the ton. 


Suppose, then, we treat 20 tons of 54 per cent. ore, to yield 1 
ton (2,000 pounds) of copper, we have ($4.38 XK 20). : $87.60 


Two thirds ton scrap-iron, at 13 cents a pound, . ‘ ‘ , 20.00 
$107.60 


Thus the cost of producing 1 ton of copper from these low grade ores is only $107.60, 
while such ore would perhaps hardly pay the cost of shipping. 

I have stated the principal points of interest to you, but have not referred to the use 
of tin plate scrap, which in most localities can be got for little or nothing, and thus 
save the cost of the scrap-iron, and materially reduce the cost of making copper. Our 
works here are not yet in full operation, but will be in the course of ten days. I shall 


* JT am told that the railways count but 2,000 pounds to the ton, so that the ten gross tons of ore would pay 
freight as 11% tons, making freight $75.20, or $11.20 more than above, which sum must be deducted from $198.20 
and added to $109, making the daily balance in favor of the Hunt & Douglass process $120. 


56 ECONOMIC GEOLOGY. 


be glad to hear from you further in this matter, and shall spend here the rest of the 


month. 
Very truly yours, T. STERRY HUNT. 


Phenixville, Pa., June 12, 1875. 


Iron. 


There are several localities where an abundant supply of this ore 
exists. At Franconia the ore was smelted for sixty years; and the iron 
manufactured is more highly prized than that made in other states. The 
remoteness of our state from the coal fields, and the decimation of our 
forests whereby the yield of charcoal has fallen off, have led to the aban- 
donment of iron mining at Franconia. 

The vein is of magnetic iron, associated with hornblende, epidote, gar- 
net, mispickel, and other minerals. It is stated by Jackson to be from 
3% to 4feet wide. It has been opened for several hundred feet on the 
steep south slope of Ore hill in Lisbon, and hence is unnecessarily ex- 
posed to accumulate rain-water. A shaft is situated low down, said to 
be 150 feet deep. At the upper end of the cut there is a curve in the 
vein, amounting practically to a bonanza, beyond which the direction 
taken by the vein is uncertain. ‘A short adit on the west side of the hill 
beyond did not discover the vein, as was expected. The vein dips 70° S. 
40° E. The rock on the west side of the vein is hornblende schist and 
gneiss. 

Furnaces were erected for the manufacture of iron here in 1811, and 
continued in blast till 1870. Charcoal was the fuel employed. Dr. Jack- 
son has given a full account of the special process of the manufacture of 
the iron, to which those interested are referred. It seems that the an- 
nual yield varied from 250 to 500 tons of pig iron, of which a part was 
reduced to wrought iron ina forge. The following figures expressed the 
cost of manufacture: 


The proportions used in charging the blast furnace were 15 bushels of charcoal, 5 
boxes each containing 56 pounds of magnetic ore, one box of limestone for flux. The 
average daily product was 2% tons of pig. From 200,000 to 300,000 bushels of charcoal 
were annually consumed, taking 160 bushels for each ton of iron made. Hard wood 
charcoal cost $4 per hundred bushels, spruce or soft-wood charcoal, $2.50 per hundred. 
The limestone cost $1 per ton. The ore cost $6 per ton at the furnace at Franconia 
village, two or three miles distant from the mine. The items were these: mining, $5; 


METALS AND THEIR ORES. 57 


hauling, $0.50; breaking, $0.50. The average product of cast-iron was 60 per cent. 
on the ore smelted, being a loss of g per cent. Jackson’s assay was the following: 
magnetic oxide, 96.20, silica, 2.30, titanic acid, 1.50100. Metallic iron, 69.04. Ten 
miners were employed at the rate of $15 per month. The pig sold in 1840 at the 
furnace for 2 cts. per lb., castings at § cts. per lb., and bar iron at 54 cts. At the 
furnace 100 laborers were employed for six months, and half of them for the balance 
of the year. The furnace buildings and the miners’ houses are still standing. From 
a detailed statement of the superintendent, the operations for 1838 showed an expendi- 
ture of $14,128.63; sale of pig and scrap, $14,594.98; sale of castings $7,309.12,— 
total, $21,904.10. Excess of receipts over expenditures, $7,775.47. 


At the present day the mining could be effected more cheaply than in 
1840. A miner living at Sugar Hill assured me of his ability to con- 
tract for the delivery of ore at the surface for $2 per ton, provided means 
were taken to drain the excavation. His plan was to open the vein so 
low down that the water would make no trouble. 

Dr. Jackson mentions two other places in the state where the natural 
facilities for the manufacture of iron are as good as those at Lisbon, viz., 
at Bartlett and Piermont. The following sketch of the Bartlett locality 
is furnished by Mr. Huntington. The other statement is by a friend, 
who is well qualified to judge of the value of ore deposits. 


Iron Ort IN BARTLETT. 


A little south of west from the village of Jackson there is a high mountain ridge, 
the eastern extremity of which is known as Baldface. This ridge extends to the 
western slope of Mt. Crawford, but it is cut by the valley of Rocky Branch, and 
also by a stream, Razor Branch, in the western part of Bartlett. This ridge, for the 
most part, is a coarse granite, composed chiefly of feldspar and quartz, but it contains 
some mica, and generally manganese. In this granitic rock, in the northern part of 
the town of Bartlett and east of Rocky Branch, occurs the most extensive deposit of 
workable iron ore ever found in New Hampshire. 

In the ridges that project south from the ridge just mentioned the granite is ofa 
different texture, being more compact, and the feldspar, instead of being a light flesh- 
color, is a dull gray, and more distinctly crystalline. This rock forms the precipitous 
cliffs north of the road running from Jackson to Upper Bartlett. North of the granite 
containing the iron and forming the mountain south of the settlement in Jackson 
known as Green hill, the rock is a mica schist which passes into a quartzite. The 
schist dips N. 40° W. at an angle of 25°, and hence it rests upon the granite. On the 
eastern slope of the mountain is a schist entirely different from that which forms the 


VoL.v. 8 


58 ECONOMIC GEOLOGY. 


mass of the mountains; and besides, it has an easterly dip, and it seems probable that 
it is the remnant of a synclinal axis that once filled the valley of Ellis river. 

This deposit of iron has been known for many years, and was first noticed by Mr. 
Meserve. It was visited by Dr. Jackson, and is thus described by him: 

“«One of the veins at the upper opening measures thirty-seven feet in width in an 
east and west, and sixteen in a north and south direction. The second opening, two 
hundred feet lower down the slope of the hill, exposes the ore, maintaining the same 
width. Three hundred feet lower down the vein is observed to narrow, and is but ten 
feet wide, and four hundred feet farther down the width increases to fifty-five feet. 
Five hundred and forty-six feet lower still there is a small opening or cave twenty feet 
deep, where the ore narrows again. On searching to the westward of this great vein, 
at a distance of two hundred and fifty feet, we soon discovered a new one, which 
appears to be of the largest dimensions. * * * Forty-nine feet farther west- 
ward the soil is full of angular fragments of the ore, indicating another vein. It is evi- 
dent that this mountain is intersected by a great number of veins of excellent iron ore, 
and will furnish an inexhaustible supply. It is proper here to remark, that it is com- 
posed chiefly of the peroxide of iron, combined with a small proportion of the protox- 
ide, and it contains a little oxide of manganese. From the composition of the ore we 
know that it will make excellent iron and the best kind of steel.” 

Fifty tons of the ore were sent to Sampson & Co., celebrated English iron and steel 
manufacturers, who have reported favorably upon its good qualities. In my examina- 
tion of this ore deposit, the measurements for mapping the property were made by 
Daniel Barker, Esq., of Bangor, Me. Starting from the most westerly outcrop on the 
slope towards Rocky Branch, we found the principal outcrops to lie in a direct line 
running N. 42° E., and the entire distance one hundred and seventy-five rods. The 
last outcrop on the east is six feet in width. Measurements of the openings on the 
west slope towards Rocky Branch were made by Dr. Jackson when the mine was first 
opened, and could be done much more exact than now. In several places, particularly 
north of the line followed, there are indications of iron, which may prove as extensive 
as the beds already opened. 

An analysis of the iron ore by Mr. Williams is as follows: 


Peroxide of iron, ’ ‘ ‘ 3 7 ; 7 . 5 ‘ 69.4 
Quartz and feldspar, . : . z ‘ ‘ ‘ é i . 25.2 
Oxide of manganese, ‘ ‘ . a : : 4 ‘ 2.7 


69.4 of peroxide, containing 48.117 per cent.’of metallic iron. 


Another specimen yielded,— 


Peroxide and protoxide of iron, . r ; : 3 . “ 77.25 
Quartz and feldspar, ‘ F A i : : 3 ‘ “ 21.40 
Alumina, . . 3 , ‘ . ‘ ‘ ‘ ‘ : ; 15 
Manganese, . e : : : - . - : . ‘ 1.20 


Or 53 per cent. of metallic iron. 


METALS AND THEIR ORES. 59 


The masses of ore seem to be in vertical segregations. Consequently there is more 
uncertainty as to their extending to a great depth, than if the ore occurred in lodes in 
a stratified rock; but this uncertainty is in a measure counterbalanced by the large 
masses in which the ore here occurs. 

Until recently this ore has been far from any means of transportation by railway; but 
now the Portland & Ogdensburg Railroad, which extends through Bartlett, will pass 
within three miles of the mine, and a branch road can be easily built up Rocky Branch 
to a point where a tramway can be constructed to the shaft, and thus the ore can be 
moved altogether by steam. 

The following may be considered a fair estimate as to cost of mining and profits : 


200 tons of ore per day, at $2.64 per ton, . . : ‘ 3 $528.00 
General expense, ‘ e ‘ F ; ‘ % 5 % 50.00 
Freight to Portland, . . F . e : : ‘ . 300.00 

Entire cost, . 5 . ‘ ‘ e . é 6 7 $878.00 
Value of ore at $6 per ton, . 5 . : 3 F 3 « $1,200.00 


which leaves a margin of $322 per day as profit on a capital not exceeding $160,000. 
The following is an estimate for a day, provided the ore is smelted in the valley of 
Rocky Branch near the mine: 


200 tons of ore, at $2.64 per ton, . “ 3 7 : 2 3 $528.00 
16,000 bushels of charcoal, at 8 cents per bushel, F i - 1,280.00 
30 furnace men, at $3.50 per day, 8 3 Fs ‘ . 3 70.00 
160 laborers, at $1.50 per day, . . . . : z 5 240.00 
Limestone for flux, ‘ ‘3 3 - ‘ 7 i : ‘ 100.00 
Repairs, etc., 3 , - 5 ; ‘ : ‘ j ‘ 40.00 
General expenses, . : - 5 é : ‘ 3 250.00 
Freight on 100 tons of iron to Portland, H : . : a 170.00 

$2,678.00 


These figures, at the present (1871) price of pig iron, would leave a very large margin 
for profit, although the necessary outlay for the construction of furnaces, etc., would 
greatly increase the capital stock to be employed in carrying on the operations. The 
ore could probably be extracted, especially if it is done by open mining, at a much less 
cost than we have given in the above estimate, the location being favorable for this kind 
of excavation. The mine is owned by E. S. Coe & Co., of Bangor, Me. 


The other statement is as follows, in a letter penned after two days of 
examination, dated November, 1873. 

There is really iron upon Iron mountain, and some of the ore of excel- 
lent percentage; but it occurs the most capriciously of any iron I have 
ever come across, and the workings have not as yet revealed any reliable 


60 ECONOMIC GEOLOGY. 


body of ore. In one of the little drifts, out of which apparently the 
greatest part of the rich ore has been taken, the rock seems barren on 
the right hand, and on the left, before you, and, strangest of all, under 
your feet. There is no vein; and yet, while the ore occurred pocket-like, 
it does not lie segregated in any wise from the containing rock, but 
passes into it on every side by imperceptible gradations. Appearances 
at some spots suggested the idea that the common rock of the mountain 
had been impregnated by the vapor of metallic iron rising from below at 
points where fissures and seams in the country rock permitted it. If this 
theory be correct, while there must be a large body of iron somewhere 
down below, all the ore anywhere near the surface would be in chimneys 
of entirely capricious distribution. 


Piermont. On the road from Haverhill to Piermont, running due south-east from 
Haverhill Corner, a mile and a half from the village, a ledge of mica schist crosses the 
road, whose strike is N. 25° E., and the dip 45° N. N. W. Three miles out, a second 
ledge of the same rock crosses, having the same strike and dip, but here becomes more 
quartzose. This ledge shows strie running 10° west of north. Three and three quar- 
ters miles out, a third ledge crosses, of the same rock, in which are quarries of flag- 
stones and whetstones, the latter known as ‘‘ Pike’s quarry.” The excavation here on 
the south side of the road shows the rock striking due north, and dipping 45° W. 

Four and a half miles from Haverhill, in the north-eastern part of Piermont, East- 
man’s brook passes through the depression between Iron Ore mountain and the north- 
ern extension of Piermont mountain. At the falls in this passage is a saw-mill. That 
part of the ridge north of the stream, in which alone mining has been done, is likewise 
known by the name of Cross’s hill. The first of the old workings, made thirty years 
ago, is in the open pasture, a few rods below the saw-mill and about thirty feet above 
the road, from which it is visible. A small outcrop of the ledge has been entered here 
to the depth of a couple of feet. About 70 feet above this in the edge of the woods is 
a second working, the most extensive, apparently, which was made. Here the ledge 
dips 25° S. S. W., with an outcrop of 12 feet perpendicular, in which the working was 
made laterally some 8 or Io feet. The mountain, following the same general strike 
as this ledge, is on its north-west side seamed with numerous parallel outcrops, most 
of which lie above the one which has been worked. The summit is 250 feet above 
working No. 2; and from this point the ledge can be seen seaming Piermont mountain 
jn the same manner on the south side of the stream, a quarter of a mile distant. Fol- 
lowing the ridge north-easterly, about 50 rods from the end summit and some little 
distance below the ridge line, in the woods, is working No. 3. Half a mile north-east 
of the summit, in the edge of the open pasture, near the northern end of a small pond, 
is working No. 4. Here a cut has been made into the ledge transversely from a point 


METALS AND THEIR ORES. 61 


five or six feet below the outcrop on the hillside. “All these workings have been upon 
the same ledge, which runs persistently the whole distance, and indefinitely further 
with the extension of the mountain. 

The rock of the mountain is quartzite, whose numerous outcrops have all the same 
general strike and dip given above. It is in layers, varying from half a dozen inches to 
as many feet in thickness, and is generally gray, though in some layers brown in color. 
At working No. 2, a few feet west of the layer principally worked, is a band one foot 
wide of pure white quartz, which would serve as an excellent guide in tracing this ore- 
bearing ledge. Very many of the layers have disseminated through them, in intimate 
commixture with the quartz, the peroxide of iron in its micaceous form. In the most 
highly impregnated layers the amount is sufficient to give the cleavage face of the rock 
the specular lustre and a black color; but its transverse face is a dull gray, from the 
superabundance of quartz. Most of the ore seems to have been taken out from a layer 
three feet wide; but this is not specially richer than its neighbors, and its impregnation 
variés in different places. Nowhere is there a true metallic vein. 

The ore, while mingled with quartz beyond the possibility of washing, has none of 
those impurities which deteriorate the metal. The richest portions might yield as much 
as 60 per cent. of iron; but the vast mass of the rock would not average 30 per cent. 
Of the ore, such as it is, there is any amount, for the iron-bearing ledge could doubt- 
less be entered anywhere in its course with substantially the same results as where it 
has been worked. The ore could not, under the most favorable circumstances, bear 
transportation. 

At Winchester a magnetic ore, carrying 24.26 per cent. of metallic iron, occurs in 
three beds situated upon the opposite sides of a gneissic anticlinal, whence it is prob- 
able that six beds outcrop. The thickest is somewhat less than 40 feet, dipping 40° E., 
exposed for 200 feet. The smaller beds are five or six feet thick, opened about eight 
feet deep for 200 feet, and dipping 30°-5o° W. These beds were wrought and aban- 
doned before 1800, the ore having been smelted at Furnace village in Winchester. 

Of other localities, Thorn mountain in Jackson shows several veins of magnetic ore 
in granite, from a few inches to two and a half feet wide, running N. 25° W. on the 
top, and N. 55° W. on the west side of the mountain. Dykes of basalt cut the veins, 
which afford 37.99 per cent. of metallic iron. The magnetic iron of Unity contains 62.6 
per cent. of metallic iron; and the hematite of Lebanon 65.17 per cent. The hematite 
of Black hill, Benton, yielding 62.4 per cent. of metallic iron, is from six inches to three 
feet in width, and quite irregular, contained in a granular quartz. Bog ores of consid- 
erable amount, containing from 36 to 55 per cent. of metallic iron, are mentioned in 
the towns of Eaton, Barnstead, Charlestown, Haverhill, Lebanon, Milford, Lancaster, 
and Pelham. Additional localities of like account, of all three kinds, are in the towns 
of Warren, Haverhill, Bath, Landaff, Franconia (east part), Lyman, Dalton, Gorham, 
Berlin, Gilmanton, Moultonborough, Jackson, Pittsfield, Barnstead, Merrimack, Bed- 
ford, Amherst, Lyndeborough, Peterborough, Swanzey, Gilford, Freedom, Grafton, 
Eaton, Enfield, Canaan, and Orford. 


62 ECONOMIC GEOLOGY. 


The following table gives the results of Dr. Jackson’s analyses of iron ores from vari- 
ous parts of the state, some of them said to be of considerable importance: 


: u a 
= o i 9 
a|/aleaile|/s)/a/a]s 
Thorn mountain, Jackson 54-8] 43.6leeenenlecsecsleceserleceees 1.6 | 37-99 
Unity—magnetic 90.4] 4 Gr Bl accsorstarsilio'siaiape | reieiacozs)| eee aie 62.6 
Winchester—magnetic, ......cccessecececeeeveccccesenas 34 6666) 22 nates oieorcds mas spaces | ca tna 24.26 
Lebanoo—ieiatiit nexiwsesasve eens ears 94 (Gilsson see | enaraearso NRetanatats all acaba oth ciutar 65.17 
Benton—hemiatite ve ssisse cx sues aviewicree ve ts casera go Ce Cees ees Gees een 2 62.4 
Eaton—bog ore..... cece cece cence cee e nea csnoenes Wsitesiteneta 72 EQ: || arasaceiece TOS | eia:eesdsedl esesesdecce 4 49-92 
Barnstead—bog ore.. 71.6] 9.4|e--e.. GiB haversrarsces| eveiare ++] 9.2 | 49-97 
Barnstead—nodular.,..... inoue bao scossnyegeie at utaiacekesiavareresavsioteve 52.8] 2.8}...6.. 10.8] 2.4]seueee 30 36.5 
Charlestown—bog Ore ...esec ese ceen cece en ee cece cennnees 69.4] 4.6}.-.... 18.6|Trace - 48) 6.92] 48.12 
Haverhill bogiOre :sseiclwis.cianjeeitnirinterece wie vicwiercare afelas 72.6) 4.6)...... TA 8 | esciaseees eresatnners Io 50.52 
Lebanon —bogione sisters tice’ vaisvcsrasere va ais apcreelgieans oe ayaietstelainn 70:6) FG) se TSk Pees apvont| sarees 5.8 | 48.65 
Milford—bog ore.... 80 Bo fesaees BuBhiccertedi laguna 3-2 | 55.67 
Laineaster—bop ores ia eaciiigaeeuacseansnen tiie sence 7i.2|  2.6}...... 5am ocr] Leecioeee 14.2 | 46.56 
Leap. 


Lead is very widely disseminated. In nearly every town of the state 
you will find a tradition to this effect: “A few years since, my uncle, 88 
years old, died. He knew of a valuable vein of lead upon the mountain. 
Was told of it by an Indian, who used to take an axe, chop off a lump of 
the ore, melt it, and run it into bullets. Uncle never told me exactly 
where it was, but there must be a magnificent vein of lead on the moun- 
tain.” Without doubt this is a correct statement, as lead is very com- 
mon; and those who have patience to explore the mountain over may be 
rewarded for their pains. With the little space left, I can only briefly 
mention the most important of our known lead openings: I will com- 
mence with a description of the Madison mine, written by me in 1870, 
Jackson has described this more fully in his report. 

Madison Lead Mine. The rock is a quartzite, near an immense sandy 
plain, where rock exposures are almost unknown. An egg-shaped exca- 
vation has been made into this rock not less than forty feet wide, and 
perhaps sixty feet long by seventy-five deep. The wall rocks have a 


METALS AND THEIR ORES. 63 


high westerly dip, and the vein is six feet wide. The ores are galenite 
and blende, of which only the former is utilized at present. There isa 
force of twenty-five men employed to mine, raise, sort, and crush the 
ore, which is sent to New York to be smelted and to be resolved into 
lead and silver. Prof. Seely’s assay of the galenite shows that it contains 
of silver to the ton of 2000 lbs., ninety-four ounces, eleven pennyweights, 
and five grains, or nearly eight pounds. 

This mine was first worked in 1826. It has been occasionally worked, 
but never so energetically as at present (1870). There is machinery on 
the ground worth $50,000, including one steam-engine of eighty horse- 
power, a second of fifteen, a twenty-four stamp mill and Cornish crushing 
rolls, capable of crushing a ton of rock in ten minutes. During the past 
winter the amount of ore dressed to seventy per cent. of lead has aver- 
aged one barrel per day. In the spring, and at present, this rate of pro- 
duction has been doubled. The actual selling price is $113 per ton, or 
$55 for the silver and $58 for the lead. 

This mine has also supplied zinc-blende in abundance. No use could 
be made of it, as, until recently, there were no furnaces in the country 
capable of reducing it. Not long since 100 barrels of this zinc ore were 
sold to parties in New Jersey for $6 each, whereas they should have 
brought as much as $20. Those who have zinc-blende in abundance 
would do well to save it, and watch the market prices given for it. 


A mile east of Madison station, on the Portsmouth, Great Falls & Conway Railroad, 
not far from the north-east corner of Silver lake, galena has been exploited at several 
points upon the same mineral belt. This has been proved for as much as three eighths 
of a mile, within which distance three openings have been made upon it by as many 
different parties. At the northernmost, known as the ‘‘ Burke property,” the most 
work has been done, two shafts having been sunk to the depths of 30 and go feet 
respectively. The next opening, going southward, is known as the ‘‘ Banks shaft,” 
and is 45 feet deep. The next, called the ‘‘ Hoyt shaft,” is down 27 feet. The ground 
occupied by these three companies is no more than should have been consolidated 
into one mining property. The vein, so called, is a mineralized band in the ferrugi- 
nous gneiss of the country, evidently persistent in its occurrence, and believed by some 
to be the extension of that at the well-known Madison lead mine, which lies four miles 
to the south-west. The vein strikes N. 15° E., and, like most bedded veins, has a varia- 
ble dip, ranging in this from 45° to go° W., at most points nearer the latter. Its sub- 
stance is quartz, white and gray, spotted frequently with a soft greenish-yellow magne- 
sian mineral. The ores are galenite, blende, and pyrites, preponderating apparently 


64 ECONOMIC GEOLOGY. 


in the order given. In such of the rock thrown out as was visible, they do not occur 
any of them in large nodules, but scattered in specks through the gangue, and in such 
form that much would be unavoidably lost in the necessary process of mechanical 
concentration. A fair average sample, taken from the accessible output of the 
«« Banks shaft,” of such rock as would have to be worked, crushed without any separa- 
tion of ore from gangue, showed,—in the hands of a professional assayer,—gold, 0.01 
0z., silver, 3 0z., to the ton of 2000 lbs. 

Shelburne Lead Mine. About 14 miles west of Shelburne station, on the Grand 
Trunk Railway, Lead Mine brook empties into the Androscoggin on the north side. 
Following up this brook 14 miles, a branch comes in from the west through a narrow 
gorge on the eastern declivity of Mt. Hayes. At the junction of the two brooks are 
the ruins of ore-separating works, run by water-power, and of three log-cabins. We 
are here at an elevation of 130 feet above the Androscoggin. Taking the western 
branch, a further walk of about forty rods brings us to an abrupt turn in the brook at a 
right angle, the stream coming down over the cliff, which forms the northern wall of 
the gorge, in a cascade thirty feet high. The mineral vein runs along the bottom of 
the gorge, much of its course in the very bed of the stream. At the abrupt turn above 
mentioned the first opportunity to attack it above water-level has been availed of to 
drive an adit westerly into the mountain upon the vein itself. The adit is 5 feet by 4, 
and extends about 30 feet. Within a distance of fifteen rods from the adit three shafts 
have been sunk in the bottom of the narrow gorge, so close to the brook, and their 
mouths so little above its level, that the most ordinary rise would flood the entire 
workings. This metalliferous deposit has been worked at several different periods by 
different companies, and the adit was an after-thought of a later company. One of the 
shafts is stated to be 80 feet in depth, and another 275, and to have proved the vein 
eight feet wide at the lowest point reached, carrying in places six inches solid ore. If 
this be so, the vein at the surface is evidently ‘‘a pinch,” and the adit could have given 
no practical vantage without the sinking in it of awinze. At the present not only 
are the shafts flooded,—they were this probably twenty-four hours after the pumps 
stopped,—but the floor of the adit is under water, so that it is impossible to learn 
much of the deposit without a considerable amount of actual work being done. The 
vein, which is one of segregation, has a strike N. 75° E., and a dip 70° N. 15° W. 
At its surface its width ranges fram two to six inches. The gangue is quartz, which 
on the hanging-wall is quite pure, while on the foot wall, which is ill defined, it grades 
into a micaceous gneiss. The chief ore carried is galenite, associated with a very 
dark blende, and a notable amount of pyrites. The galenite seems to be invariably 
mixed with these ores, while on the other hand the pyrites occurs in some places unas- 
sociated. A sample of galenite with pyrites, gave, in the hands of a professional 
assayer,—gold, none; silver, 15.06 oz. to the ton of 2000 Ibs. This ore was almost 
free from gangue, and may be considered a favorable sample. From the fact that so 
many parties have worked this,—one of the historical mines of New Hampshire,— 
always with the result of abandonment, it would seem a fair inference that however 


METALS AND THEIR ORES. 65 


wide the vein may have become in depth, and however rich the ore, the ratio of ore to 
gangue must have been too small. 

Galena has also been exploited during recent years at a point a few miles farther 
west on Mt. Hayes. The results were unsatisfactory, and the workings unextensive, 
compared with those just described. 

Silverdale Mine. In the south part of Pittsfield, on the Suncook river and the 
Suncook Valley Railroad, is the hamlet known upon the maps as ‘‘ Webster’s Mills,” 
called more recently upon the neighboring guide-boards, ‘‘ Silverdale.” The exploita- 
tion for silver-lead has been on the east side of the river, about one fourth of a mile 
north of the bridge, upon the first bench above the immediate river-bottom. The 
southernmost shaft is that at which the most work has been done, and from which 
the specimens in the state cabinet were taken. A few feet north of this is an untim- 
bered cut, ten feet deep, which simply serves, being dry, to show the vein for that 
slight depth. Several rods further north is a third opening, known as the ‘‘ Couch 
shaft,” apparently off the vein. The two shafts are full of water; but a resident of 
Silverdale, familiar with the workings, states that the first is about 35 and the second 
about 30 feet deep. The vein is a ‘‘ bedded” one, and, along with the synchronous 
country rock, has a general strike N. 34° E., and a dip 85° N. 56° W. It averages 
two feet wide, the gangue of quartz carrying the ore in perpendicular seams running 
parallel to the vein walls. The foot-wall on the east is of white gneiss, reticulated 
with little quartz veins, and its plane of demarcation from the vein is very definitely 
marked. The hanging-wall is indistinctly defined, the vein-rock grading into a quartz 
characterized by greenish-yellow and brown patches of softer mineral, sometimes 
nodular, and sometimes angular in outline. Blende runs through the vein in sheets 
one half inch thick persistently, occasionally widening into bulges one half foot thick, 
blotched with large-crystalled galenite. On the border of the vein the rock carries 
considerable pyrites in minute sprinkled crystals, and occasionally chalcopyrite in 
small blotches. 

A furnace has been erected at the bridge for smelting the galenite under a new 
patent, said to contain original and valuable features. The furnace-house being 
locked and the key temporarily out of town the day the locality was examined, no 
description of it can be given. An assay of the Silverdale ore gave 1.6 ounces of 
silver to the ton. 

Loudon. In the central part of the township of Loudon galena has been exploited 
at the locality called ‘‘Buswell’s Mine.” The opening is on elevated land, the 
aneroid showing a height of 300 feet above Pittsfield station on the Suncook Valley 
Railroad. The shaft was not only full of water, but planked over at the time the spot 
was visited, so that little idea could be formed of the mine. There is plainly no vein, 
the opening having been made in what is apparently the rock of the country, though 
it might, on more extended examination, prove to be an exceedingly wide trappean 
dyke. This rock has a general strike N. 40° E. and dip 80° N. W._ It is porphyritic, 
the included crystals, most commonly one half inch long and one sixteenth wide, 

VOL. Vv. 9 


66 ECONOMIC GEOLOGY. 


showing very distinctly on surfaces slightly weathered. There is likewise considerable 
included quartz. The galenite occurs in small blotches, showing a tendency to form 
in the centre of quartz nodules. It is unusually dark-colored and splendent, plenti- 
fully sprinkled with minute crystals of pyrites. The entire quantity of ore is slight. 

Rumney. Upon porphyritic gneiss in the north-east part of the town is a vein 
owned by George L. Merrill. The metalliferous mass is 12 feet wide, exposed in an 
excavation 14 feet deep. The walls dip 80° N. 70° W., enclosing a soft feldspathic 
rock with some quartz. Two kinds of trap rocks are situated in the vein, dark- and 
light-colored. The galena and blende follow reticulating veins of quartz, inter-pene- 
trating the general mass. The galena contains a trace of gold, and 1.95 oz. of silver 
to the ton. 

North Woodstock. Wandsome specimens of galena, blende, and pyrites have been 
shown us from Horner’s farm. Some work has been done in the way of opening 
the vein. The galena shows a trace of gold, and 7.84 oz. of silver to the ton. 

flooksett. Upon the quartz ridge south-west from the Pinnacle is a small lead vein. 
The best part of it shows three inches width of galena. This is hardly sufficient for 
mining. 

Other localities are in Bath, Haverhill, Epsom, Nashua, Lyndeborough, Dunbarton, 
Tamworth, Sandwich, Lyme, and elsewhere. 


TIN. 


Tin ore has been discovered in Jackson in such quantity and so re- 
lated that miners have thought a good vein of it might be developed by 
diligent exploitation. From time to time prospectors have searched the 
neighborhood, particularly in Maine, where greater success has been met 
with than in our state. Dr. Jackson was greatly interested in the sub- 
ject, particularly as this was the first discovery of the ore in so great 
quantity in the country. From investigations made about 1840, the 
following conclusions have been derived: 


The rock of the country is a mica schist dipping 30° N. E. by E., with veins or 
elvans of granite crossing it. The ore is cassiterite, occurring in four veins, making a 
triangular space of 200 to 300 square feet by their intersection. No.1 is mostly com- 
pact ore, eight inches in the widest part, yielding 30 per cent. of tin, associated with 
chalcopyrite and mispickel, and the course is N. 7° E. No. 2 contains crystalline ore 
with mispickel, half an inch wide, running N. 80° E. in granite. This ore crosses 
the others, like the horizontal line in a figure 4. No. 3 is a compact ore in mica 
schist, from half to three quarters of an inch wide, running N. 56° E. No. q is nearly 
parallel to the last, from a half to an inch and a quarter wide. No. 1 is cut by a dyke 
of trap. The rock near the veins contains from two to ten per cent. of tin. The 
other minerals found with the cassiterite are mispickel, pharmacosiderite, chalcopyrite, 


METALS AND THEIR ORES. 67 


native copper, wolfram, fluor, and molybdenite. In 1843, eleven and a half ounces of 
ingot tin were obtained from the Jackson ore; but the mine never seems to have been 
worked steadily, though it was being mined at the time of my visit in 1864. 

The following notes in regard to the working of the tin mine were furnished by 
Mr. George N. Merrill, as also a view of the tin locality, and a profile (Fig. 8) show- 
ing the situation of the schist and shafts. 

«<The American Tin Company was chartered by the legislature of New Hampshire 
July 15, 1864, and they issued sixty thou- 
sand shares at $5 per share. The company 
vactually expended and paid out $4,371.69. 
The last work done at the mine was in 
August, 1865. The company sunk two 
shafts, one twenty-five the other forty-five 
feet, and made an adit ninety feet. To 
have reached the main shaft would have 
required an adit 400 feet in length.” The 
rock excavated from the adit is composed 


“yaoy 06 “IP 


mainly of a uralitic sienite not found else- 
where. This may furnish a clue to the kind 
of rocks carrying tin. 

Considerable time has been devoted to 
exploring the country between Madison and 
Milan, where it was supposed, from the 
character of the rocks, that tin might be 
found. In many places there are indica- 
tions of metallic deposits, but for the most 
part they are iron sulphides, at least on the 
surface, while a few blasts might reveal 
something more valuable. Every new mine 
that is discovered has characteristics pe- 
culiar to itself, and these have to be care- 
fully studied before any one can form a 


“Jaoj cob “YeYs UleUI 0} JIPe Jo souULIQUA WOIy DOULISICL 
‘NOSHOV{ ‘ANIJ[ NIT, LY SONIMYOM AO NOILOAS—'g ‘SIT 


correct judgment in regard to it. Minerals 
present themselves, too, under so many 
different phases, and when exposed to the 
atmosphere are often so changed as scarce- 
ly to be recognized, that no one, unless he 
has made explorations, can form any esti- 


mate as to the time required or the labor 
necessary to be performed. Hence, explorations for tin in New Hampshire require 
the expenditure of considerable means in costeaning and sinking shafts before it will 
be possible to pronounce definitely that the metal cannot be found. In going from 


68 ECONOMIC GEOLOGY. 


Robertson’s Corner to Madison Corner, just after passing the height of land south of 
the road, we find the schist in many places pyritiferous, and often much decomposed. 
There are also numerous beds of granite, or possibly they may be nothing more than 
immense veins. The schist, where it does not contain pyrites, is similar to that in 
Jackson where tin has been found, and here it belongs to the Montalban series. In 
Jackson, every locality where it was thought there could be any show for tin was 
examined, and an analysis of many of the specimens collected has been made by 
Prof. Seely, and very rarely has there been found even a trace of tin. The most 
promising localities away from the old opening are in the valley immediately north of 
Thorn mountain and on the west slope of the Black mountain, and the tin rocks here 
underlie the andalusite schists, at least on south end of Black mountain, and appar- 
ently uncomformably. On the west side of Tin mountain, near the Dundee road, the 
schist is pyritiferous, and there are numerous beds of granite; the rocks seem to be 
quite similar to those on the opposite side where tin has been found. Going north, 
the entire western slope of Black mountain, from its base half way up, seems to be 
composed of pyritiferous schists, beds of granite, and gneiss. There is a promising 
locality near Mr. J. R. Harriman’s; also, near the place formerly occupied by Mr. J. Y. 
Perkins. 


BismuTH, MANGANESE, ARSENIC, AND MoLyBDENUM. 


Native bismuth has been found upon Sunapee mountain, near New- 
bury. Nothing further than the fact of its existence is known. Manga- 
nese is not common in large amount. Bog manganese is reported in 
Gilmanton, Grafton, Lisbon, Haverhill, Laconia, Rindge, and Nelson. 

In Winchester and Hinsdale is a bed of impure rhodonite 8 feet thick, 
according to Jackson, enclosed in gneiss, dipping 70° S. 60° E. in the 
first, and 84° easterly in the second locality. When this mineral is pure, 
it is highly prized for ornamental purposes. 

The arsenical pyrites—mispickel or arsenopyrite—is very common in 
our state. It is most abundant along the Connecticut valley, both mas- 
sive and crystallized. Localities of note are Jackson, Francestown, Ha- 
verhill, Lebanon, Weare, Groton, Lisbon, Lyman, Middleton, Dunbarton, 
Epsom, and Alton. Should the manufacture of arsenic ever be called 
for, New Hampshire can afford a plentiful supply. This mineral is worth 
studying as a possible source for gold, silver, cobalt, and nickel. 

Molybdenum occurs quite abundantly at Westmoreland. Dr. Jackson 
examined the locality with care, and thinks the mineral is plentiful. It 
is the sulphuret, associated with blue compact feldspar and quartz con- 
taining apatite. Experiments have not been made to satisfy us whether 


METALS AND THEIR ORES. 69 


the compounds of this metal can be used successfully as a mordant 
in the dyeing of cloths. The blue color of the compounds is one of 
great beauty. The papers have occasionally stated that parties have pro- 
posed to reopen the mine and extract the ore, but our visits have never 
found evidences of recent work there. I annex a careful description of 
the locality by a friend who visited the place at my request: 


The old workings on Lincoln’s hill, Westmoreland, in a gneissic rock, which is 
characterized by a predominance of mica and quartz, the latter having in many spots 
a bright red color, so that the outcrop is suggestive of ferruginous quartzite. The gen- 
eral course of the ledge is N. 40° E., with a dip of 50° N. W. The outcrop in which 
the surface work was done is on the side of a slight depression in the hill; and here 
the rock has been blasted to a depth, on the upper side, of 5 or 6 feet. From this point 
the ledge can be traced down the hill 270 paces to where it is intersected by a dry water- 
course, the outlet of the above mentioned depression, beyond which, on the opposite 
swell, itis not seen. Above the pit outcrops are visible to a yet greater distance on 
the rising hill. About 50 paces below the pit an adit has been carried into the knoll 
from the bed of the water-course, which here is parallel with it. The adit bends a little 
to the east in its further part, but its general course is straight, and may be set down 
as E. 20° S. It is 4 feet wide, about 6 feet high, and 35 feet long. The precise height 
it is impossible to give, for the reason that, at the time of its being visited, it was filled 
with water and ooze to the depth of three feet, with an unknown amount of débris be- 
neath this. The rock is schistose, and notably micaceous at the surface, but at the 
distance of a dozen feet becomes massive. The walls of the adit are so covered now 
with the exudations and incrustations of more than thirty years, the period which has 
elapsed since the abandonment of the work, that it is impossible to tell, without putting 
in a blast, into what it has been pushed. It is pretty plain, however, from the absence 
of any seaming of the walls at its further extremity, that it has not entered any vein. In 
the pit before mentioned the vein exposed is of quartz, about two inches wide, and car- 
ries molybdenite, granular and in small scales, often in radiating clusters. In its pres- 
ent appearance, and the character of the loose fragments of the gangue lying in the pit, 
the vein gives no evidence of richness; but it would be unwarrantable, without clear- 
ing and blasting, to express any opinion upon this point. 


CHAPTER II, 


BUILDING MATERIALS, ETC. 


e this chapter I propose to enumerate the principal quarries whence 
stones used for building purposes are obtained; mention whatever 
facts have been obtained respecting the quantity of material sent to mar- 
ket; the names of the companies; number of men employed, etc. The 
articles used for building are properly granite, slate, flags, clays for 
brick, limestone, and soapstone. Other useful articles, obtained from 
the earth for direct use, or capable of special manufacture, are quartz and 
feldspar for glass; mica, plumbago, precious stones, whetstones, copperas, 
alum, titanium, polishing powder, moulding sand; and ochre for paint. 
These all occur abundantly within our limits, 


GRANITE. 


So common is this rock that New Hampshire is usually known as the 
Granite State. In every-day life this term is applied to rocks which are 
not properly granite in the technical sense, as sienite and gneiss, but all 
of them useful for building. In the stratigraphical and mineralogical parts 
of our report, different classifications are employed. In the first instance 
are the Concord, Conway, Albany, Chocorua, and other geographical 
terms, used for convenience. In the second instance, the names of the 
peculiar constituent minerals are employed to distinguish them,—as the 
biotite, muscovite biotite, and hornblende granites. It will be unneces- 


BUILDING MATERIALS. 71 


sary in this connection to make extensive use of either of these classifi- 
cations, though they will be referred to many times. 

In every part of the state the common gneiss rocks are used for stone 
walls and the underpinning of buildings. No mention can be made of 
such material, but only of those that are of superior quality, or what, on 
account of convenient situation, have been extensively employed in the 
villages. I will first mention all the facts in my possession respecting 
the quarries, their locations, proprietorship, capabilities, etc., reserving 
any generalizations to subsequent pages. The economic facts have 
been chiefly collected in the spring of 1878. 

A very large number of our quarriers operate upon a stone like that 
obtained in Concord, and hence familiarly known as the Concord granite, 
or the muscovite-biotite variety. Those of this character are known in 
Concord, Hooksett, Salem, Pelham, Nashua, Milford, Fitzwilliam, Troy, 
Marlborough, Roxbury, Swanzey, Plymouth, Manchester, Farmington, 
Sunapee, and Mason. 


Concord. The granite quarries of Concord are situated one to two miles north-west 
from the city, on the easterly slopes of Rattlesnake hill. The Concord & Claremont 
Railroad runs at the north-east foot of this hill, and the granite is loaded upon its cars 
at points one fourth mile to one mile south-east from West Concord station. Two of 
the quarries nearest to this station are beside the railroad; the distance teamed from 
others varies from one eighth to three fourths of a mile. 

The largest of these quarries are those of the Concord Granite Company and the 
Granite Railway Company. Nine other quarries are worked at the present time. The 
number was somewhat greater in 1873, which was the last of several years marked by 
unusual business prosperity ; and the number of men employed and the value of granite 
sold by the larger proprietors, all of whom still continue operations, were during these 
years two or three to ten times as great as now. 

Brief notes respecting the Concord quarries are as follows: 

Concord Granite Company: Alfred Sampson, president; E. C. Sargent, treasurer 
and agent. This quarry was first opened about twenty-five years ago; owned as now, 
with a large business, since 1860. In 1873, about 25 men were employed in quarry- 
ing, and 200 in cutting, the annual sales amounting to about $200,000; in 1877 this 
company have employed about 8 quarrymen and 30 cutters, with sales of $20,000. 
Largest block quarried, 20 tons; it is claimed that a solid block 100 by 25 by Io feet 
could be got at this quarry. Buildings from it are that of the Presbyterian Board ot 
Education, in Philadelphia; Booth’s theatre, in New York; the Advertiser and Herald 
buildings, in Boston; and the Custom House in Portland. 

Granite Railway Company: Henry E. Sheldon, agent. Quarry opened in 1861. In 


72 -ECONOMIC GEOLOGY. 


1873, about 20 quarrymen and 80 cutters were employed, with sales amounting to 
$200,000; there are now 4 quarrymen and 25 cutters, with a yearly product of $20,000. 
Largest block, 18 tons; could supply one 40 by 20 by 6 feet in dimension. Buildings 
from this quarry are the Equitable Life Insurance Co. (above the basement), Staats 
Zeitung building, and Germania Savings Bank, in New York; the Charter Oak Life 
Insurance Co. (above the basement), in Hartford; and the City hall and Horticultural 
hall, in Boston. 

Norton & Holmes (formerly, till 1878, P. E. Blanchard’s quarry): opened in 1865. 
In 1873, 20 men were employed in quarrying and 60 in cutting, the yearly sales being 
about $45,000; they are now $8,000. This quarry supplied the basement and trim- 
mings for the first three stories of the Tribune building, New York; the Washington and 
Eddy street fronts of the City hall in Providence; Bemis block, near the Transcript 
building, in Boston ; and the Soldiers’ monument in Georgetown, Mass. 

Donagan & Davis: quarry opened in 1872. In 1873, 15 quarrymen and 4 cutters 
were employed; sales, $75,000. No quarrying has been done for two years. Some 
fo cutters are now employed, the sales being about $10,000. The largest block of 
granite ever taken from Concord was supplied by this quarry, being the base of the 
Soldiers’ monument at Marlborough, Mass., 84 feet square by 34 feet thick, weighing 
224 tons. Shafts could be got 18 feet long and 4 feet square. The building of the 
New England Life Insurance Co., in Boston, was from this quarry. 

Fuller & Pressy: quarry opened in 1865. In 1873 about 25 men were employed in 
quarrying, the sales amounting to $20,000; now 15 men are employed, the sales being 
about $7,000, all unhammered stone. The largest blocks supplied have weighed 15 to 
20 tons; shafts could be got 18 feet long and 3 feet square. Jordan & Marsh’s build- 
ing in Boston is from this quarry; also, the Manchester, N. H., Soldiers’ monument. 

Abijah Hollis: quarry opened in 1865. In 1873, 12 men were employed in quarry- 
ing; at present about 8 are at work. All the stone is sold: rough: Largest blocks 
ever sent away, 18% tons; could get a block measuring 100 by 30 by 12 feet. Exam- 
ples of the stone from this quarry are the Ether monument, Boston public garden; 
the Cadet monument, Mount Auburn cemetery; and the Soldiers’ monument at Con- 
cord, Mass. 

Gay Brothers: quarry opened in 1865; purchased by present owners in 1876. Men 
employed in 1873 and now, about 6,—all in quarrying. 

Crowley & Quinn: quarry opened in 1864. In 1873, Io men, all at quarrying, with 
sales amounting to $5,000; in 1877, 3 in quarrying and 4 in cutting, with sales of 
about $3,000. Largest block, 104 by 5 by 33 feet; could supply shaft 20 feet long and 
3 feet square. 

Putney & Nutting: quarry opened about 1850. In 1873, 6 men were employed, all 
in quarrying, with $5,000 sales; now, very little is done. The Masonic Temple in 
Boston is from this quarry. 

G. W. Emerton: quarry opened in 1875; 5 quarrymen and 5 cutters; yearly sales, 
about $8,000. 


BUILDING MATERIALS. 73 


Charles A. Bond: quarry opened in 1877, employing 5 men. 

The principal dealers in hammered granite in Concord, not owning quarries, are 
P. E. Blanchard, who employs 15 men at stone-cutting; Hunton & Perry. 18 men; 
John H. Flood, 15 men; Blanchard & McAlpine, 1o men; and Flanders & Gannon, 
12 men. 

Hooksett. In Hooksett two granite quarries are worked. They are near together on 
the east side of the Merrimack, two miles south of the village and about half a mile 
from the Concord Railroad. The upper quarry, which yields the finer stock, was opened 
as much as fifty years ago. For several years past it has been worked by Oliver Gay, 
by whom the lower quarry, used principally for bridge masonry and rough work, was 
opened in 1873. At that time 30 men were employed in quarrying and 10 in cutting. 
In 1877 both these quarries were purchased by A. L. Waite, who employed last year 
about 15 men, principally in quarrying. Proprietors in 1878, Bonney & Waite. 

Salem. A quarry in Salem, opened about forty years ago, owned since 1870 by David 
Nevins, of Methuen, is situated one third mile west-south-west from Salem depot. Ten 
quarrymen were employed here several years ago, but very little is done now. 

A visit to the Nevins quarry, in 1875, showed that the rock is strictly gneiss, dipping 
50° N. 70° W., with prominent vertical joints running N. 65° W. There was a cap of 
poor rock overlying the workable stone, requiring removal before good material could 
be obtained. This was 25 feet thick in some places. Both the horizontal and vertical 
joints exist here. The opening is shaped like the letter L, 300 feet long, measuring 
both arms, and 100 feet wide. The ground is low, so that pumping is required to re- 
move the water. 

Pelham. In Pelham, the greater part of the quarries are on Gage’s hill, two miles east- 
north-east from the village. The nearest railroad stations are Salem and Messer’s, on 
the Manchester & Lawrence Railroad, four and a half miles distant. A proposed rail- 
road from Nashua to Plaistow would pass at the north foot of this hill. The distance 
to be teamed from the different quarries would then vary from one eighth of a mile to 
one mile. 

The largest business here is that of Bodwell & Webster, for whom Samuel Kelley is 
agent. This quarry was opened about 1850. It has been under the present owners 
since 1873. In 1874 and 1875 about 6 men were employed in quarrying and 4 in cut- 
ting, the annual sales being about $8,000. Last year the sales were about $3,000. 
Largest blocks quarried, about 4 tons; could supply shafts 15 feet long and 3 feet 
square. The granite is bedded in sheets varying from 6 inches to 34 feet in thickness. 
This company owns a tract of 80 acres. 

Other quarries on this hill are those of Benjamin D. Kittredge, employing about 5 
men; Abner Kittredge, 3 or 4 men; D. H. Webster & Son, 4 men; Gage & Wood- 
bury, 4 men; J. N. Woodman, 5 men; John Roney and Moses Johnson, each 2 men. 

This granite finds a market principally in Lawrence, Haverhill, and vicinity. Law- 
rence dam is built of it; and most of the stone caps and sills used in these cities are 
supplied from Gage’s hill. The stone is of fine quality, well suited for cemetery and 

VOL. Vv. IO 


74 ECONOMIC GEOLOGY. 


building purposes. The earliest quarrying upon this hill was in 1782, by Abel Gage. 
Two other quarries are situated in Pelham, 14 and 14 miles south-east from the vil- 
lage. The former is owned by Oscar F. Carlton, who employed 5 men in 1873, but 
does very little work now. The latter is owned by Calvin Coburn, who, in 1873, had 
about 15 quarrymen and § cutters. This quarry supplied the stone for the Lowell water- 
works. The granite of both quarries goes principally to Lowell, being teamed 5 miles. 
It is mostly used for rough masonry and edge-stones. The proposed Windham & 
Lowell Railroad will run near these quarries. 

Nashua. A quarry, half a mile south-west from the city, on land of the Nashua Man- 
ufacturing Company, and opened by them in 1823, has been leased and operated by C. 
W. Stevens since 1872. About6 men are employed in quarrying and 3 in cutting. The 
sales in 1873 were about $10,000; last year, $6,000. Used mostly for bridge masonry, 
edge-stones, and foundations. Largest blocks, 63 feet square by 14 feet thick; and 
slabs, for cemetery borders or for underpinning, 20 feet long. 

Milford. ‘This town has numerous granite quarries, several having been recently 
opened. Brief notes of them are as follows: 

Luther M. Burns, 2 miles south-south-west from the village: qurrry opened 75 years 
ago, being the oldest in Milford; owned as now since 1862. In 1873, 12 men were 
employed, the annual sales amounting to about $15,000. Last year the sales were only 
$2,000. Largest blocks sold have been 28 feet long, for borders of cemetery lots; 
shafts, 15 feet long and 2 feet square, could be supplied. The town-house in Wake- 
field, Mass., is trimmed from this quarry. 

Nathan Merrill: quarry near the foregoing, opened in 1873. Workmen, 3; annual 
sales, about $1,500. Blocks 20 feet long and 2 to 3 feet square can be supplied. The 
basement and steps of the Baptist church in Milford, N. H., and one of the buildings 
of the Bigelow Carpet Company, of Clinton, Mass., are from this quarry. The pro- 
posed Manchester & Fitchburg Railroad would go near these quarries. 

Thomas M. King: quarry half a mile sotth-east from the village, and about an eighth 
of a mile from the railroad; opened in 1870; owned as now since 1874. Workmen, 7; 
yearly sales, about $2,500,—one half being dimension stone, the rest being used for 
cellar walls and similar work. This granite is finer grained than most of the quarries 
in this town. Much of it lies in straight sheets, 6 inches to 1 foot thick, from which 
heavy flagstones, of any size up to 20 feet square, can be obtained. In another part of 
the quarry the beds are thicker, and can supply monumental shafts 3 or 4 feet square. 
The fire engine building in Lowell, and Merchants’ Exchange in Nashua, are trimmed 
with this stone. 

William Jones: quarry on south side of Souhegan river, 4 miles west of the village ; 
opened in 1875. Yearly sales, about $1,000. 

The following are on the north side of Souhegan river: 

Everett Hutchinson: quarry 1 mile north-west of the village; opened about 1870; 5 
workmen ; yearly sales, about $2,000. 

Daniel A. Bates: quarry about 2 miles north-west of village; opened in 1866, being 


BUILDING MATERIALS, 75 


the first quarry north of the river; owned as now since 1874; workmen, about 5; sales 
yearly, $3,000, formerly (in 1874) $8,000. 

George F. Parker: quarry near the last; opened in 1869; annual product, formerly, 
$4,000, now $1,200. 

Albert Carlton: near the foregoing; opened in 1876; workmen, 2; annual sales, 
about $1,500. 

Kittredge & Palmer: same locality; opened in 1874; annual sales, about $1,500. 

Parker Fletcher: same locality ; annual sales, about $1,000. 

Newton Perham: quarry in edge of Amherst, teaming to Milford; yearly product, 
about $1,000. 

Granite dealers in Milford, who dress the stone but do not own quarries, are Isaac H. 
Carlton, Charles S. Barnes, Marvell & Weaver, Pierce Perham, and Frank Frost. 

Fitzwilliam. The granite quarries in Fitzwilliam are principally situated beside or 
near the railroad in the vicinity of the depot. Brief notes respecting them are as fol- 
lows : 

Daniel H. Reed: quarries one half mile south of the depot; opened in 1816; owned 
and worked as now since 1864, on a tract of 300 acres, mostly of granite suitable for 
quarrying. Five openings are now worked, two of them supplying large amounts. 
Quarrymen, Io to 30; average number of cutters, 5. Sales in 1869, $40,000; now, 
about $15,000 yearly. A part of this granite lies in straight sheets, varying in thick- 
ness from a few inches to a foot, from which flagstones of any desired extent can be 
obtained. Largest block sold, 12 feet long by 4 feet square, weighing 16 tons; 
largest sheet, 16 by 9 by 1 foot. The statues on Horticultural hall in Boston, and St. 
Paul’s church in Worcester, are from this granite. 

Albert Hayden: quarry one fourth mile north of the depot; opened in 1872; 6 
workmen; yearly sales, about $5,000. Kruff’s block, Pearl street, Boston, was from 
this quarry. 

A. D. Stone & Company: quarry about 13 miles north of Fitzwilliam village, team- 
ing to Troy depot, 2 miles. Workmen, formerly, 20; no work done last year. 

The following quarries are beside the railroad, one mile west of Fitzwilliam depot: 

Ethan Blodgett & Company: quarry opened in 1867. Average number of quarry- 
men, 16; of cutters, 9. Sales in 1873, about $20,000; last year, $12,000. Largest 
block, 10 by 7 by 2% feet, weighing 153 tons. Shafts 20 feet long by 3% feet square 
can be supplied. Specialty, monumental and cemetery work. T. K. Earle’s house 
in Worcester, the court house in Fitchburg, and the trimmings of Morse Institute in 
Natick, Mass., are from this quarry. 

R. L. Angier: quarry opened in 1865. Average number of quarrymen, 8; of cut- 
ters, 8. Value of product in 1873, $10,000; in 1877, $6,000. Largest block, 16 feet 
long by 24 feet square, weighing 15 tons; could supply 20 feet long by 3 feet square; 
has sold blocks 6 feet square and 2 feet thick; could supply 10 feet square and 3 feet 
thick. Trimmings of Murdock block, and of the National Bank, in Winchendon, 
Mass., and the Soldiers’ monument in Granville, N. Y., are from this quarry. 


76 ECONOMIC GEOLOGY. 


The Flint quarry, Thomas Hale, agent: not worked last year. Formerly, 15 work- 
men; yearly sales amounting to about $12,000. 

Mr. J. H. Bigelow, freight clerk at Fitzwilliam depot, states the total amount of 
granite freighted from this town during the last five years to be as follows: in 1873, 
13,083 tons; in 1874, 8,103 tons; in 1875, 5,952 tons; in 1876, 6,867 tons; in 1877, 
5,923 tons. 

Mr. Reed and Mr. Angier can supply a dark variety of granite, containing a large 
proportion of black mica. This is chiefly used for trimmings. Polishing is done by 
Mr. Hayden and by Mr. Angier. All the quarrymen of this town sell their granite 
rough or dressed, as purchasers wish. J. E. Fisher & Co., at Fitzwilliam depot, are 
also dealers in hammered granite, employing 5 cutters. 

Troy. Two quarries have been worked in Troy. One, owned by D. M. Woodward, 
of Worcester, Mass., is situated three fourths of a mile east of the village; opened 
in 1871; formerly 5 men, all in quarrying; no work done last year. The Bank block 
in Fitchburg, Mass., was from this quarry. The other, owned by Luther Whittemore, 
is half a mile south-east of the village. Average number of quarrymen, 3; not much 
done last year. 

Marlborough. This town-has one granite quarry, 14 miles north-east from the depot. 
It is owned by A. G. Mann, of Worcester, Mass. This quarry was opened as early as 
1812; under present owners since 1868. The number of quarrymen has varied from 
10 to 40; the cutting is mostly done at Worcester. This granite lies in sheets which 
vary from 3 inches to 3 or 4 feetin thickness. Largest blocks sold, 12 tons; sheets 
have been split out 70 feet long and 6 feet wide. A considerable part of the sales here 
has been of-paving-blocks, 7 inches square and 4 inches thick. The Union depot at 
Worcester (except trimmings, which were from Fitzwilliam), and the Stone mill at 
Harrisville, came from this quarry. 

Roxbury. The south-west corner of Roxbury has valuable granite quarries. The 
largest is that of the Keene Granite Company, H. A. Bodwell, president, E. S. Bod- 
well, treasurer. This quarry is 24 miles north-east from South Keene station, where 
the company’s stone-sheds are located. The proposed Manchester & Keene Railroad 
will run three fourths of a mile distant. Quarry opened about 1850; owned as now, 
and business greatly increased, since 1872. This company own 227 acres of land, 
with a right to quarry on 150 acres more. They employed formerly 150 quarrymen 
and: 200 cutters, their sales in 1873 being about $350,000. Largest blocks sold, 12 
tons; a sheet now split out would yield a block 30 by 15 by 6 feet in dimensions. 
Most of the granite quarried by this company has been used in building the new state 
house at Albany, N. Y. At present, very little work is done here. 

The Cheshire Granite Company, S. G. Griffin, president, has a quarry a third of a 
mile west of the last; only a small amount of work done. 

Another quarry, opened about 1840, now owned by John L. Randall, of Albany, N. 
Y., is situated one mile north-east from these, being about four miles from Keene. It 
has been worked since 1873 by Nourse & Dean, of Keene, who several years ago em- 


BUILDING MATERIALS. 77 


ployed 6 quarrymen and about Io cutters. No quarrying of importance done last year. 
This granite lies in sheets which vary from 6 inches to 8 feet in thickness. Largest 
blocks moved from the quarry, 124 feet long by 24 feet square; shafts 30 to 4o feet 
long and 4 to 6 feet square could be got. The Episcopal and Baptist churches, and 
the depot in Keene, are trimmed with stone from this quarry. 

Swanzey. Nourse & Dean also lease a quarry, opened in 1863, near Westport station 
in Swanzey. It is one half mile from the railroad. About 6 men were employed here 
last year. The Episcopal church in Keene is built from this quarry. R. Stewart, super- 
intendent of Cheshire Railroad, sent the following statement about the granite business 
along his railroad for the year ending April 30, 1871: 

* * * «¢The largest proportion of the Fitzwilliam stone is sent to Boston, 
Worcester, and Lowell; while considerable from that point, as well as Marlborough, is 
seeking a market at Springfield, Hartford, New Haven, and other points reached by 
Connecticut River Railroad. The stone from Troy is sent principally to Fitchburg for 
building purposes. The tonnage for the year is as follows: Fitzwilliam, 9,458 tons; 
Troy, 1,717 tons; Marlborough, 3,292 tons; Keene, 1,040 tons; Westport, 652 tons; 
total, 16,139 tons. There are occasional shipments to local stations that would, I 
think, on actual figures of everything, show from 18,000 to 20,000 tons sent.” 

Plymouth. Your miles north-west from Plymouth are valuable granite quarries, first 
opened by H. W. Blair, in 1870. They are one half mile north of the Boston, Concord 
& Montreal Railroad, from which a branch track runs to the quarries. Since 1872 they 
have been owned and worked by Sanborn & Blair, employing from 5 to 20 men, with 
average yearly sales of about $4,500. The greater part of this granite is used for 
bridge masonry. It is also employed in cemetery work, and in building. It lies in 
sheets 2 to 10 feet in thickness, and slabs of fine stock 20 feet long can be supplied. 

Manchester. Two quarries are being worked in a bunch of granite upon the com- 
pany hill,—one, the Amoskeag quarry, and the other, Bodwell’s. The latter’s excava- 
tion was about 25 feet long, 150 wide, and from Io to 50 feet deep, three years since. 
The company’s quarry was not so large. Both were being worked energetically, as 
there is a great demand for stone in the largest city of the state. The stone is inferior 
to the Concord, though resembling it, being coarser, breaks more readily, and shows a 
slight tendency to crumble. Other quarries are about Rock Rimmon, on the west side 
of the Merrimack river, and ‘in the very twisted ancient gneiss between Hallsville and 
Massabesic lake. The foundations of the city hall, and much of the curbstone in the 
Streets, are of this latter material. The Rimmon stone is granite of rather inferior 
quality, containing bits of pyrites. 

Mason. An extensive business is carried on at the Glen quarry in Mason, owned by 
A. Macdonald, of Mt. Auburn, Mass. It is situated close to the Peterborough & Shirley 
Railroad, in the east part of the town. There are two principal openings. The one I 
saw is the more southerly, estimated to be 300 feet long, 150 wide, and 40 deep. The 
surface shows slightly the breakage by ice in the glacial period, like that observed in 
Manchester. From 25 to 30 workmen were employed in 1877. Steam is used exten- 


78 ECONOMIC GEOLOGY. 


sively. To the east is a larger opening, capable of furnishing obelisks 60 feet long. A 
large monument has been erected of this granite at Greenville, Penn. There are many 
of various sizes at Mt. Auburn. A very pretty building, belonging to the Delta Psi 
Society, is being built of this stone at Hartford, Conn. The joints in this quarry are 
somewhat irregular. Seams of kaolin clay occasionally occur in them. There are 
other quarries farther north along the railroad, doing less business than the one de- 
scribed. 

Sunapee. There is considerable quarrying done at Sunapee Harbor, very near the 
lake, on Keyser hill. A variety nearly black is found here, which is properly mica 
schist, not granite, in connection with a variety very like that of Concord. (See Vol. 
II, p. 510.) Itis marked on the county map as the Bailey quarry. 

Farmington. There is plenty of excellent granite in Farmington, hardly distinguish- 
able from the Concord stone. The area, as shown by the atlas map, is not large, but 
it is sufficiently so for all practical purposes. The quarries are about a mile and a half 
north-west from the depot, and were being successfully worked at the time of my visit 
in 1875. 


MISCELLANEOUS GRANITES. 


Several different kinds of granite are quarried in various parts of the 
state, the most important of which will be mentioned. One not very 
different in external appearance from the Concord is that of Haverhill. 


Haverhill. In the edge of Piermont, two miles south of Haverhill, are two granite 
quarries, known as the Catamount and Black Hill quarries, owned by James Barstow 
and W. H. Page. These quarries have been worked more or less for nearly 100 years. 
They have been for several years leased to Daniel J. Winn & Co., of Haverhill, who 
employed 4 men in quarrying and cutting in 1873, with sales amounting to $2,000; last 
year 7 men were employed, the sales being about $3,000. The Catamount stone is 
used principally for bridge masonry and similar purposes. The Black Hill stone is 
adapted for the finer kinds of cemetery and ornamental work. Blocks 30 feet long and 
5 feet square could be got from the latter quarry. 

Another granite quarry is worked by Hubert Eastman near North Haverhill. It has 
been worked more or less since 1840, and the sales for some seasons have amounted 
to $400. The stones have been used principally for buildings and bridge masonry. 
The largest block split out measured 60 by 4 by 4, tapering to a point. Has been 
used at Lisbon, Bath, and the adjoining Vermont towns. Has never been used for 
cemetery monuments. 

Columbia Granite. Near Colebrook, just in the edge of Columbia, is a small area of 
hornblende sienite, wrought as granite by George Parsons, of Colebrook. Its mineral 
character has been described by Mr. Hawes. The peculiarities are the presence of cal- 
cite and liquid carbonic acid. It is easily worked and handsome, coarsely crystalline 


BUILDING MATERIALS. 79 


like the Quincy granite of Massachusetts. It would make an excellent stone for orna- 
mental pillars, especially for inside work. Most of the blocks quarried are used at Cole- 
brook for buildings, not for cemeteries, the stone from Brunswick, Vt., along the Grand 
Trunk Railway, supplying that want. A few years since Mr. Parsons employed from 6 
to 8 hands constantly; now only half that number is needed. Blocks of any size that 
can be conveniently handled can be quarried here. There have been as yet no orders 
for this stone from any distant locality requiring railroad transportation. The Bruns- 
wick granite is related to that from Concord, and, being favorably situated as regards 
transportation, is used extensively in northern New England. 

St. Fohnsbury Granite Company. This concern uses granite from several localities, 
making a specialty of monumental work. They use most extensively a biotite granite 
from Blue mountain, Ryegate (one that cuts the Calciferous mica schist) ; and, on ac- 
count of the strong contrast between the white feldspar and the black mica, it has a very 
clean aspect. By leaving the letters and ornamental work raised and polished, an inter- 
esting effect is produced, as it makes a strong contrast with the main body of the stone. 
It receives and retains a high polish. Their gray granite comes from Brunswick, Vt. 
They are also beginning to use a red biotite granite from Stark, the same with one that 
has been described in the other parts of this report. It resembles somewhat the red 
Scotch granite, but is superior to the imported article, because it is finer, and is not 
permeated with the ‘‘pin-holes” constantly occurring in the other. This company is 
doing a large business. They have a mill for polishing granite close by the St. Johns- 
bury depot, using steam, and employ a large number of workmen. The use of the 
“Conway granite” from Stark is the only known instance of the extensive employment 
of this variety of stone from a New Hampshire locality. There is a good mass of it at 
Biddeford, Me., that is extensively used. 

I have the following additional statements respecting the St. Johnsbury Granite Co., 
from R. W. Laird, treasurer. The Blue mountain granite requires 24 miles of trans- 
portation to the railroad. It is entirely free from iron, and blocks may be quarried 
300 to 4oo feet long and ten feet square. Monuments made of the three granites 
were exhibited at the Centennial exhibition at Philadelphia, and the red Stark stone 
received a medal and diploma, with the following award: ‘‘ For the good quality of the 
material, the originality of design, and the workmanship of the articles exhibited.” 
80 workmen are employed in April, to be increased in the summer to Ioo. Monu- 
ments are sent to every part of the country, especially the Middle states. The red 
granite is wrought from boulders. 

Lebanon Granite. This may be taken to represent a type of granite very unlike any 
others that have been mentioned, and it is worked at Walling’s quarry in Lebanon; at 
Freeman’s, one less extensively opened, further north in the same town; on Corey hill, 
and other places in Hanover and Enfield. It is properly a protogene gneiss. Itis a 
heavy, massive stone, better capable of sustaining weight than the Concord variety. 
S. H. Walling & Son do a large business, and supply the wants of Lebanon, mainly, for 
building purposes. Stone of very large size can be obtained here. The rock is free 


80 ECONOMIC GEOLOGY. 


from iron pyrites. This cannot be said of the Hanover stone, which was used for the 
basement of Culver Hall. 

One thing should be said of this impurity in the Hanover rock. There is a building 
on Corey hill containing pieces of the pyrrhotite as large as beechnuts, and though the 
house has been standing nearly seventy years, there are scarcely any iron stains upon 
it. This species of pyrites sustains itself so well that oftentimes its presence need 
not be feared. A more remarkable instance of the ability of this pyrites to resist 
decomposition may be seen in the Francestown soapstone. I have examined many of 
the stoves manufactured from this stone, and noticed that bright particles of this 
pyrites were thickly sprinkled through it. I have also looked at pieces of this stea- 
tite that had been subjected to great heat for a long time without much change. It 
would appear, therefore, that this mineral may not be injurious to granites, as it seems 
to withstand successfully the vicissitudes of both heat and cold. 

Porphyritic Gneiss. This is: only employed locally. I have been greatly pleased 
with the appearance of curbs and foundation stones of this granite, as seen commonly 
at Lake Village and Meredith. The large rectangular white feldspar crystals render 
the stone attractive. There is a gray Scotch granite with these reddish-white crystals 
scattered through it, which is like our porphyritic gneiss. Those who desire a new 
variety may be pleased with this. The town of New Hampton abounds with hand- 
some ledges of this rock; but any of the areas thus designated upon the map will 
furnish to a careful search very attractive blocks. 

The White Mountain Granites. By these I mean the Conway, Albany, Chocorua, 
and sienite groups, of which whole mountains stand ready to be quarried, and thus be 
made serviceable to civilization. Of these, certain portions of the first are unsuitable 
for building purposes or monuments, because they disintegrate so readily. This has 
been explained (Part iv, p. 195) by the presence of innumerable pores in the feldspar 
which admit water charged with carbonic acid, and thus gradually impair the integrity 
of the stone.’ But all the Conway granite mountains are not of this character. The 
other varieties are also capable of furnishing peculiar grades of building stone, and 
perhaps the time is not far distant when their beauties will be discovered and utilized. 
Railroads now thread among the mountains, so that new quarries of stone can be easily 
transported to market. There are fine-grained varieties of the Conway species near 
the Portland & Ogdensburgh Railroad in the Notch, which are durable. A very hand- 
some stone of this sort has been used by Dr. S. A. Bemis for his dwelling, though 
more care might have been taken to secure a material free from pyrites. 


It was my intention to have presented statements respecting the 
points to be observed in selecting a good granite for quarrying, the appli- 
cation of microscopic study, and a comparison of our stone with the 
Scotch, Massachusetts, and other kinds of building material, particularly 
with reference to strength and ability to resist decomposition. The 


BUILDING MATERIALS. 81 


reader may consult Part IV for a part of this intended sketch, and the 
rest in general treatises upon building materials, since the size of this 
volume is already too great. 


SLATE. 


The only formation likely to furnish quarries of roofing-slate is the 
Cambrian range along Connecticut river. The Vermont portion has 
quarries upon it in Guilford and Thetford. There have been several 
quarries upon this belt in our state, at Littleton, Hanover, and Lebanon, 
but no work has been done upon any of them for several years. The 
stone is not quite so good as that in western Vermont or Maine, but 
certain portions might be utilized in several localities for home purposes, 
especially for curbs, platforms, tables, flags, etc. In Littleton are two open- 
ings in the north part of the town, upon the adjacent farms of Richard 
Smith and Mr. Bachelder. The band of rock suitable for working is 
nearly an eighth of a mile wide, and the principal opening has been ex- 
cavated to the depth of 20 or 25 feet. Bachelder’s quarry is the farthest 
from the road, and has had the most work done upon it. The strata are 
vertical, and, as the outcrops are on a hill, the facilities for drainage are 
good, and working surfaces can be obtained 100 feet in depth. The rock 
seemed to be free from pyrites, was soft, but does not cleave so thin as 
the slate from Maine. About two miles westerly from Littleton village 
is a large excavation on the west side of the Blueberry mountain range, 
high up, and well situated for mining. The opening is about 200 feet long 
and 50 deep, presenting a face of these dimensions. There is a cross 
cut into this opening through which the slates are transported over a 
tramway. Several houses have been erected for the accommodation of 
the workmen, and a large amount of rock has already been removed. 
The samples of slate stored for shipment appear to be of excellent 
quality. The color is a bright dark blue, and the stone soft, and appar- 
ently durable. The face corresponds with the front of the hill, so that 
the position is a favorable one for mining, the slate standing about per- 
pendicular. Thirteen years since, an attempt was made to form a com- 
pany to work the quarry, but for some reason it failed. Many of the 
layers are filled with cubical crystals of pyrites, and it is likely that the 

VOL. Vv. II 


82 ECONOMIC GEOLOGY. 


abundance of this mineral discouraged the proprietors, preventing the 
carrying on of a large business. 


In East Lebanon a company has expended $25,000 upon opening a quarry and erect- 
ing a mill, but the work is now abandoned. The property consists of 100 acres of land, 
about 100 rods in length, along the course of the slate, with a fine water-power,—the 
Mascomy river,—and situated by the track of the Northern Railroad. Over $4,000 has 
been spent in opening the quarry, under the superintendence of E. L. Cleaveland, pre- 
senting a vertical face about 55 feet broad and deep. I saw slabs 15 feet square, and 
others, larger, can be obtained. The valuable part of the bed is 30 feet in width. The 
mill on the Mascomy is 44 feet wide, 65 feet long, and three stories high. It contains 
machinery driven by water-power, put in at an expense of $8,000, requiring the services 
of 20 workmen when fully equipped. The slate is not used for roofing, as it does not 
split sufficiently thin, but may be used for the manufacture of chimney pieces, table- 
tops, shelves, etc., and marbleized like the slate of western Vermont, where this busi- 
ness has been successfully conducted for many years. The other uses of the stone are 
for sinks, cisterns, burial cases, flooring, tiling, etc. ; and the waste is ground and bolted 
into slate flour, of which the company sold 150 tons in 1868. In continuing the quarry- 
ing, some difficulties arose requiring a further outlay of capital, insomuch that the 
company became discouraged and suspended operations, the superintendent having 
accepted a position at the Copperas Hill establishment at. Strafford, Vt. 

Other openings have been made upon Moose mountain, Hanover, and Croydon 
mountain in Cornish. 

Flags. Such slates and schists as are suitable for flagstones are chiefly what have 
been described under the Cambrian and Cois schists of the Connecticut valley. They 
are all comparatively soft, and will not compare for durability with the blue stone from 
Hudson river, which is used so commonly in the larger towns of lower New England. 
All stones of this sort that have been quarried in our state are only used locally. 


LIMESTONE. 


Haverhill, In the east part of Haverhill is a large bed of grayish- 
white limestone situated in gneiss, It is about a mile and a half from 
the East Haverhill station, on the Boston, Concord & Montreal Railroad. 
There are several openings in the bed. The rock is partly bluish-gray, 
resembling that wrought at Thomaston, Maine, and partly white and 
coarsely crystalline. It has been seen for 800 feet in length and 400 in 
width. Dr. Hayes’s analysis of it is the following: Carbonate of lime, 
94.04; carbonate of magnesia, 1.36; carbonate of iron, .58; phosphate of 
lime, .22; quartz, silica and mica, 3.80=100. ‘This sample was varie- 
gated gray in color, and contained the quartz, silica and mica as rock 


BUILDING MATERIALS. 83 


mixture. It will afford 53.7 per cent. of lime, to which will be added 
four parts only of earthy matter. Much of the lime in the market con- 
tains 27 per cent. of earthy and foreign matter. Some samples I saw of 
the limestone contained less earthy matter than the sample analyzed.” 

In 1864 a pamphlet was prepared by Nicholas Mason, descriptive of 
the properties and capabilities of this stone, from which it appears that 
the entire cost of making the limie was 30 cents per cask. At Rockland, 
Maine, the corresponding expense is given by Alden Ulmer, inspector, 
at 80 cents per cask. 

Lisbon Limestone. In Lisbon lime is also manufactured by Orren 
Bronson to the amount of 2,200 casks annually. The bed is shown on 
the several maps to extend several miles through the eastern part of the 
town, and to crop out on different stratigraphical lines. The thickness 
is not so great as in Haverhill, but great enough to supply a kiln for 
many years. Some parts of it were thought to approach 100 feet in thick- 
ness. Four different quarries were wrought forty years since, consisting 
of Mr. Bronson’s, Thomas Priest’s, David Priest’s, and Uriah Oakes’s,— 
the others to the north-east of the first, and within four miles’ distance. 
The T. Priest bed is 13 feet wide; it has been explored for 300 feet in 
length, and can be wrought to the depth of 60 feet without the necessity 
of pumping. There is a slight curvature to the bed. As shown on the 
map, the range continues to the furnace in Franconia, broken twice. The 
opening north of Sugar hill supplied the furnace with material for fluxing 
the iron ore. There is another range of limestone parallel with the Bron- 
son-Oakes belt, about two miles to the north-west, following a back road 
from Salmon Hole brook to the South Branch. Quartzite is associated 
with it. 

Orford and Lyme. In Orford and Lyme is another development of 
limestone identical in character and geological position with those of 
Haverhill and Lisbon, and it is essentially continuous for 10 miles near 
the west edge of the gneiss. On the west side of Cuba mountain a bed 
has been wrought at intervals for fifty years. Some of the beds are 20 
feet thick, and several run close together, as at Tillotson’s quarry, where 
the aggregate thickness of the limestone is 38 feet. I suppose there 
must be beds of limestone upon Lime hill, though none are marked there 
upon the map. On the Charles Scott place, in Lyme, are beds 6 feet in 


84 ECONOMIC GEOLOGY. 


thickness. Massive garnet and crystals of hornblende occur in connec- 
tion with the enclosing beds. Dr. Jackson describes a mixture of lime- 
stone and granular quartz on the same farm 120 feet in thickness. Anal- 
ysis shows it to be quartz mixed with silicate and carbonate of lime. It 
consists of silica, 80.40; lime, 14.72; magnesia, 1.12; oxide of iron, 0.88; 
carbonic acid, 2.88=100. It was recommended for the manufacture of 
glass. On Holt’s hill is a bed of limestone one foot thick, in company 
with iron pyrites. The limestone crops out conspicuously in East Lyme 
where the road branches to Dorchester and Canaan. The region of these 
limestone beds in Orford and Lyme is now very sparsely inhabited, inso- 
much that the road at the west base of Smart mountain is almost impass- 
able. 

Littleton, Lime has been burnt in the Helderberg limestones of Lit- 
tleton in at least two places. One is about three miles to the north of 
the village on Burnham’s hill. Two extensive openings occur here, show- 
ing a breadth of stone from 10 to 60 feet thick. The other locality is on 
Parker brook, about a mile west from the depot. Both these kilns were 
in action some thirty years since, and produced an excellent quality of 
lime. It was brown after burning, but slacked white. The amount of the 
stone is abundant, as has been mentioned in the discussion of the Hel- 
derberg formation. The stone near Parker river is unusually white. 
Another mass of stone, seemingly 40 feet wide and of better quality than 
the last, occurs on Fitch hill, a mile south-west from the brook locality. 
This rock forms a knob in a pasture beyond the best fossil outcrop. Still 
another opening occurs back of J. K. Corey’s house, in the south part of 
the town, near the Ammonoosuc river. By examining the geological 
map, one will see that the Helderberg group extends southerly upon 
both flanks of Blueberry hill; and good outcrops of limestone may be 
looked for in almost any part of the blue-colored areas. That for a mile 
along the river in North Lisbon is largely composed of a white lime- 
stone, but it is not free from silica and rock, and would not answer so 
well for the manufacture of quicklime. 

It is our belief that nearly all the beds mentioned are capable of 
furnishing a good quality of lime. It is equally strong with that fur- 
nished from Maine, but usually makes a brown mortar like that from 
Weathersfield, Vt., which, by the way, is exactly the same material as 


BUILDING MATERIALS. 85 


the Haverhill and Lisbon stones. Because the mortar is not a pure 
white it has fallen into disuse, and the Maine or Vermont limes em- 
ployed instead for finishing. Our stone would furnish good material for 
three fourths of the plastering needed for honses, or it may be used for 
agricultural purposes. As it is inexhaustible, there is no reason why the 
farmers should not order it in large quantities. 


At Lime pond, in Columbia, the marl has been used to some extent for the manufac- 
ture of quick lime. This article is fully equal to the best imported variety; but the 
supply is not inexhaustible. 

Limestone occurs in many other towns in New Hampshire, but in a comparatively 
impure condition. It occurs in Plainfield, Cornish, Claremont, Clarkesville, Stewarts- 


town, Amherst, Warner, Wakefield. I append a few analyses of some of these rocks, 
by Dr. Jackson: 


a ts fe le Tee 3 
¢ 2 of Q :|e8 : & 
2 (28/32) 86 a| 3 
is Bg | 2#6| Be) 46/8] 3 a3 
@g|8e/82)/csileag/815} 8 
of | 2 ro el |/2 a 3) og 
=o] a5] 4 BSl/osa | RE] EI s on 
a |o JO | |O {O18 ae 
Haverhill—first quality fi || GOS! | ascssinicedel aicisiasy Or2 |eweele eee /55-7 |= 100 
Haverhill—second quality.......e.cesecseeneeeeeeneee 3-80] 90.66]. ..0..|seeeee 5+ 54] ++] 200+15%.03|=100 
Thomas Priest, Lisbon.....--ssserescrereeeeceensees 8.2 | 90-18]. ..00-fesaees I : 100 
David Priest, Lisbon. ... 1... sseeccereeseeensesseeees E556 | 8206) |e cccorcees| ecsiveoes 2.8 [eeee[eeee [45-6 
Uriah Oakes, Lisbon—flux.......sceceeseesaseeessens| 20 | B80. [eceees lessee 2 |rse-]eee-]43-9 |=r00 
Ee ee ee te ee fl peiand agains 2.60]...+...+|40.35|==100 
Eyme—dark colorediieccsssisavesscsacesceesseawvel 28 | 8996 |seceslosovas 1.2 | 2 |..--147-04|=100 
Orford .csmnsicscesaiedsaemonsecseiersees sen, 64 90 frozese »-/50.66/=110.4 
Amherst ss ccacucicciesersscrgeee eset Gees! er | Se2) [ees .»142.32|==98.6 
‘Warner—white crystalline ..........eeeceueeeereereee 33 B6x4. ween Bee ey Roe + ++[20,8/32.74|=100.2 
Warner—gray siliceous ...... 020. .cseeeee cnet een eee 72 10 13 Bue ||eeseree sexeleass| S262 =98.2 
Cornish—Judge Jackson ...... ccc cseeceeecrcenssecees 3r | 58.6 1.6 FES | a siniscce seeebesee]32-98|—=99.2 
(Saini 
Tunen Durie: Vitissessssctisiesciersyerecoyn winie diwiwintecnserainielaterEaasecs ies 40.6 47.6 ET! “Vesainioiece =99.2 
PAN stesescsticierose sel bai wfaratteaverstate sates lara iwievetn’sieratcrwieveiorsie 25 23.8 | 46.6 «+ [13.39]=98.3 
Cornish—Johnson’s Quarry ....ccceceecerveecereeceee 59-6 | 22.6 | 13.8 -+|15.72|=99.8 


Brick Cray. 


A few facts have been acquired relative to the manufacture of bricks in the state. 
They relate to the largest establishments. 

The extensive deposit of clay in Pembroke, Allenstown, and Hooksett, has been 
described on page 94 of Part III. The brick-makers find a slight difference between 
the gray and blue clays,—the latter requiring more sand to be mixed with it, and 


86 ECONOMIC GEOLOGY. 


shrinking more in burning. Brief notes respecting the manufacture of brick in these 
towns are as follows: 

Natt & William F. Head, Hooksett, make about five millions of brick yearly, em- 
ploying 60 men. Their market value, loaded on cars, has ranged from $6 to $10 per 
thousand. They are sold largely in Manchester, Nashua, Lowell, Lawrence, and 
Worcester. 

Jesse Gault, Hooksett, manufactures three to four millions yearly, employing 40 
men. 

Other brick-yards are those of William G. Andrews, Hooksett, employing 5 men; 
Jabez Green, Suncook, 5 men; Charles Bailey, Suncook, 5 men; Philip & Warren 
Sargent, Suncook, 20 men; Edmund Elliott, Pembroke, 5 men; Henry T. Simpson, 
Pembroke, 20 men. These yards will average about 80,000 brick yearly to each man 
employed. 

; Brick-yards formerly worked, but idle for the last two or three years, are owned by 
Cochran & Russ, Suncook, and by James Thompson, Hooksett. 

The brick-makers in Plaistow are as follows: Moses Goodchild, manufacturing about 
1,000,000 brick yearly, employing 15 men; J. S. Lamprey, about 1,500,000, with 15 
men; Isaac H. Pollard, 800,000, with 8 men; H. H. Cheney, 700,000, with 7 men; 
Isaac Hall, 500,000, with 5 men; George Denoncour, 1,000,000, with 10 men; D. 
Gauselain, 500,000, with 5 men; J. W. Porter, 500,000, with 5 men; Alack Janell, 
I, 000,000, with 10 men; Joseph Kimball, 500,000, with 5 men. 

Bricks are made also at Dover Point, Rochester, Lebanon, Keene, Bedford, Bos- 
cawen, Bristol, Bartlett, Claremont, Haverhill, Concord, Durham, Epping, East 
Kingston, Francestown, Franklin, Greenville, Hampton, Hancock, Hillsborough, 
Jaffrey, Lancaster, Littleton, Merrimack, Moultonborough, Newport, Northumberland, 
Ossipee, Plymouth, Rindge, Rumney, Great Falls, Unity, Warren, Winchester, and 
Wolfeborough. 


SoAPSTONE. 


The Francestown Soapstone Company, with a capital of $300,000, has 
its mills for sawing at Nashua, and commenced operations, on a larger 
scale than had been employed hitherto, in May, 1866. The bed had been 
discovered originally by Mr. Daniel Fuller, in 1794, while engaged in 
ploughing. It was first wrought in 1802; and stone was transported to 
Boston for sale as early as 1812. Previous to 1866, about 2,000 tons 
of stone had been sold; 1,500 tons were sold in 1866, and 2,020 in 1867. 
The company made 3,700 stoves in 1867. I have no statistics of the 
extent of manufacture since this date; but the business is known to have 
been conducted upon a similar large scale ever since 1866. The refuse 
fragments and dust are also utilized, being ground and sold for packing. 


BUILDING MATERIALS, 87 


I have visited this locality several times. The bed is regular, not nodu- 
lar like the steatite and serpentine beds in Vermont. The opening is 80 
feet.long, 40 wide, and 80 deep, a little wider at the bottom than at the 
top. The bed has been followed for 400 feet in length. The peculiarity 
of the stone consists in the uniform distribution through it of spherical 
radiated aggregations of crystalline plates of talc. These make the stone 
uniformly strong in all directions, unlike most of the Vermont rock, 
which is apt to split along seams of original structure. The Frances- 
town stone has largely superseded that from Vermont for the manufac- 
ture of stoves. I have already alluded to the dissemination of minute 
crystalline bits of pyrrhotite disseminated through the soapstone without 
seemingly injuring it. 

The presence of radiated spherules marks this bed in its stratigraphical 
distribution. Other beds of it are found in Weare, Warner, Canterbury, 
and Richmond. The first named is near the top of Mt. Misery, and has 
been quite extensively opened by Hon. M. A. Hodgdon. I saw it first 
in 1869, and judged the bed to be 15 feet wide and quite hard. The 
stone had the same lithological features with that in Francestown, and 
occupies the same stratigraphical position. The excavation was about 
10 feet deep. Two or three years later, the bed had been better defined 
by additional excavation. The hole in 1874 was seen to be 71 feet long 
and 60 feet wide, representing the width of the soapstone. Two or three 
large bunches of hard rock—horses—occur in it, one of them estimated to 
be 35 feet long. In going down there was seen, first, the common country 
rock, underlaid by a coarse-grained ledge with long hornblende crystals 
capping the soapstone. The latter rock.is at the top inferior to that 
found lower down. Small bunches of granitic rock occurred occasion- 
ally; and the pyrrhotite showed itself in a vein three inches wide. The 
work was prosecuted far enough to determine the nature of the stone 
underneath the principal horse. The material was soft, but somewhat 
shelly. The great improvement in the appearance of the stone over what 
it was on the surface leads us to believe that good material will event- 
ually be quarried here. 

Mr. Hodgdon has also opened the ledge in the south-east corner of 
Warner, in the same bed, or its repetition by a fold. The bed is over 20 
feet in width, and deserves to be opened more fully. 


88 ECONOMIC GEOLOGY. 


In Canterbury, this rock has been quarried near the Boston, Concord, 
& Montreal Railroad, a mile and a half south of the station. A hasty run 
over the ground showed the presence of two beds, each about 25 feet 
wide, separated by hornblendic rocks. One bed has been opened in two 
places. I have been unable to learn anything about the history of the 
work done here, and do not know why the quarry has been abandoned. 
It is very near a railroad, and conveniently situated for working. The 
stone is only partially like that from Francestown, occurring more like 
those in Vermont. 


Circumstances have prevented such exploration of the country between Francestown 
and Canterbury as was anticipated. I have one impression of the relations of rocks to 
the soapstone that may be of value to others. The Canterbury bed lies just above a 
prominent belt of white feldspathic or granitic material. This may therefore be the 
guide to the occurrence of the soapstone. I have observed it in the west part of New 
Boston, and in Hopkinton. (See Vol. II, pp. 589, 159.) 

Other localities of soapstone, of greater or less interest, are in Richmond, on land of 
Lorenzo Harris ; boulders in Hampstead, Pelham, and Dracut, Mass. ; and 14 miles east 
of E, Hill’s in Swanzey. This last named bed has not been mentioned heretofore, and 
is not located upon the map. I have no facts in regard to it to present. 

Orford. Five beds of soapstone occur in this town, one in the Huronian, the others 
in the Cods mica schists. They are all of good quality. Some facts about them are 
found on pp. 382-4, in Volume II. 

Hfaverhill. The soapstone quarry in Haverhill, now controlled by David Page, is 
situated about three miles north-east of North Haverhill station. It was first opened 
in 1855, and was worked up to the middle of the winter of 1857. About 150 tons were 
taken out and sent to market. The stone was pronounced to be of a fine quality for 
the first opening. The quarry then changed owners, and was not worked again until 
1874, when some 50 or Go tons of the stone were taken to market, and found to be of 
very good quality for all purposes for which soapstone is used. It is claimed that it 
can be brought to a finer edge than that from any other locality in the United States. 
It can be quarried in large quantities, and of almost any dimensions. The Boston, 
Concord & Montreal Railroad is 14 miles distant. 


MANUFACTURE OF GLASS AND POTTERY. 


Excellent materials for the manufacture of glass and pottery are abun- 
dant. The feldspar occurs in the coarse granite veins carrying merchant- 
able mica. This range has been described in Volume II, page 514, ex- 
tending from Easton to Surry, being of a fibrolite mica schist, and is 


BUILDING MATERIALS. 89 


admirably shown upon the map. At almost any part of this range these 
coarse granite veins are liable to occur. Masses of it a foot square are 
common wherever the veins have been opened. It is now thrown away 
because it cannot be utilized.. Our feldspar has been successfully used 
in the manufacture of artificial teeth by several dentists. The time is 
coming when our immense supplies of feldspar will be utilized. We 
have no beds of kaolin or porcelain clay that are of value. Quartz, valu- 
able for the manufacture of glass, is exceedingly common. The ranges of 
it which I have represented upon the map, and fully described in Volume 
II, are nearly all sufficiently pure for this purpose. These occur, first, 
through Hillsborough, Rockingham, and Strafford counties on the east, 
and from Cheshire to Grafton on the west side of the state. Very fre- 
quently there are large hills, hundreds of feet high and broad. In Lynde- 
borough there is an establishment fitted up for the manufacture of glass, 
based upon the presence of one of these beds of quartz. Although milky 
white, the quartz contains a small percentage of iron, and is therefore apt 
to impart a green color to the bottles manufactured. The iron is removed 
by first burning the stone in a kiln, so as to magnetize the hematite and 
limonite present; secondly, the brittle calcined rock is pulverized; thirdly 
and lastly, the powder is caused to fall over revolving cylinders bristling 
with magnets. These attract the iron, and thus purify the pulverized 
material, which is now ready to be put into crucibles. A very large busi- 
ness is done at Lyndeborough. 


Mica. 


Our state is celebrated for its mica. It occurs in enormous quantities, 
suitable for commercial use, in immense, coarse granite veins, where the 
three mineral constituents are found in large pieces. The mica I have 
seen in plates a yard long, but 10 or 12 inches is a more common size. 
On account of the great value of this mineral, we have taken special pains 
to learn where it is distributed, as it does not occur at hap-hazard any 
more than veins of the metals. Upon the. map we have distinguished a 
mica schist with fibrolite, one of the supposed divisions of the Montalban 
group. It is usually about two miles wide, and reaches from Easton to 
Surry, with occasional interruptions. It is extraordinarily developed 
about Rumney and Hebron, spreading out to fill the space between the 

VOL. Vv. 12 


go ECONOMIC GEOLOGY. 


two great areas of porphyritic gneiss. Those who search for this min- 
eral will find that the valuable deposits of mica are to be found chiefly 
within this fibrolite area as delineated upon the map, corresponding with 
that of the feldspar. 

Quarries for mining mica have been opened in the following localities: 
In Grafton, the oldest and best known establishment is that of the Rug- 
gles company, upon Isinglass hill. About 1840 they obtained some 600 
or 700 pounds annually, valued at $1,500. In 1869 they marketed 75 
boxes of 350 pounds each, worth from $2.15 to $2.50 per pound. This 
makes a total of 26,250 pounds, worth perhaps $60,000. In January, 
1877, the Ruggles mine is said to have shipped 3,600 pounds of mica, 
selling for $2 per pound. They employed, in 1869, 12 men for seven 
months of the year. Within two or three years the price of mica has 
increased, and hence the business has been much stimulated. Grafton 
now has six openings, which are all worked. Mellen’s quarry is about 700 
feet above the valley, to the north of the Ruggles mine. There are six 
or eight places where excavations have been made. Martin & Page are 
at work energetically, near the top of Alger or Beryl hill. This is the 
locality where the largest known beryl was once on exhibition. These 
parties have worked here for two years. Another place is opened by 
Kilton & Sargent. On Hoyt hill in Orange is the Worcester mine. The 
vein shows for 400 or 500 feet near the hill-top, and its maximum width 
is 100 feet. Five men were employed here at the time of my visit. The 
largest plate of mica obtained here is 8 inches square. There are two 
other mines on the east side of the railroad in Grafton. There are others, 
in Alexandria, New Hampton, Wilmot, Marlborough, Acworth, Alstead, 
Groton, and Springfield. The Alstead quarry has been worked intermit- 
tently the past thirty years by Mr. James Bowers, who sold in 1840 one 
thousand dollars’ worth to the Boston market. His quarry is on Beryl 
hill, a famous locality for the latter mineral. On Hall’s farm in Groton 
are unusually large plates of mica, where no mining has been done. The 
Springfield locality has furnished beautiful and large tourmalines. 

Those who drive about Springfield, Grafton, Orange, etc., cannot fail to 
see these veins on the hill-tops, whitening their crests and sides. The 
vein on Hoyt hill, Orange, is quite conspicuous on the right-hand side, 
as the cars near the summit from the south. Aaron’s ledge in Spring- 


BUILDING MATERIALS, 9g! 


field is a landmark 15 to 20 miles away. The range seems to terminate 
with the Colonel Sanborn hill in Springfield; but I have found limited 
patches of it, not shown upon the map, near George’s mills. The mica 
of New Hampshire is extremely abundant, and there is no danger that 
the supply will be exhausted for many generations. 


PLUMBAGO. 


This mineral is found in Goshen, Antrim, Bristol, Nelson, Hancock, 
Chester, Mt. Monadnock, Sutton, Barrington, Bedford, Troy, Walpole, 
Washington, Hillsborough, Keene, Wentworth, Orford, and elsewhere. 
It is not equal in quality to that obtained at Ticonderoga and other Lau- 
rentian districts, but sells readily for a second quality article, and is use- 
ful for the manufacture of crucibles. The most extensive mine is at 
Goshen, formerly owned by President Pierce. It is on the flank of Sun- 
apee mountain, included in pyritiferous mica schist, and accompanied by 
radiated black tourmaline. The bed is small, and traversed by a better 
quality of the same mineral in cross veins. The amount raised and sold 
annually has varied greatly. In 1840 the yield was 20 tons. A few 
years later the product was greater; and the locality is capable of fur- 
nishing a larger supply, should it be called for. 

The Antrim bed is irregular in thickness, varying from a few inches 
to two feet. The material is said to be soft and pure. 

Few minerals are talked of more than plumbago by the farmers, as 
they often find it in an impure condition. A good article is free from 
grit, and can be readily cut with the knife without coming into contact 
with hard bunches. To those searching for it, I would recommend ex- 
ploitation where the rocks are most crystalline. All our mica schists 
show the mineral, but it is apt to be impure. 


Precious STONES. 


These are not abundant; but very beautiful specimens of beryl, garnet, 
cinnamon stone, amethyst, rose quartz, iolite, and other minerals are often 
found, which are suitable for being cut as gems. I refer the reader to 
Part IV for a description of the minerals and localities. 


92 ECONOMIC GEOLOGY. 


PoLisHING PowpeEr. 


Chapter XIV, Volume I, is devoted to a description of the organisms, 
which by their decay give rise to the white, light earth sometimes called 
infusorial silica. It is liable to occur beneath any bog in the state. The 
few deposits we have are of excellent quality, and the quantity is suffi- 
cient for commercial use. The largest deposits are at Umbagog lake, 
Fitzwilliam, Stark, Tamworth, and on Stamp Act island, Wolfeborough. 
Others are known to exist at Bemis lake in Livermore, Littleton, Laconia, 
Bristol, Chalk pond in Newbury, Epsom, Bow, in a pond north-west from 
the Crawford house, White Mountains, Concord, Manchester, Durham, 
Grafton, and Exeter. The Fitzwilliam deposit is sold extensively for a 
polishing material. The principal use made of this article at the present 
day is in the manufacture of dynamite, and it commands a price of from 
$15 to $18 per ton. The most northern locality is in Cambridge, upon 
Umbagog lake, near W. M. Thurston’s, where it occupies, in the lake, on 
the islands, and on projecting points of land, an area of fifty acres or 
more. It varies in depth from a few inches to two feet, although, as our 
observations were limited, the depth may be in places much greater. It 
is covered in the lake by a lacustrine deposit, and on the islands by an 
accumulation of soil. 

In the town of Stark we find it in Pike’s pond. It is here known to 
be three feet in depth, and it is probably much more. It seems to be 
distributed over the entire bottom of the pond. 


WHETSTONES. 


These are quarried in Piermont and Haverhill by Mr. Pike. I have 
not his figures for the number of stones produced; but the business is a 
large one, and the material is inexhaustible. Other towns along the Con- 
necticut river contain the same rock. 

Two localities of novaculite or oil-stone are capable of supplying plenty 
of oil-stones. One is upon Fitch hill in Littleton, near the Helderberg 
fossils; and the other is at the north base of the Ossipee mountains. 
The place may be known by the fact that certain dark streaks in the 
stone have been mistaken for the rocks accompanying coal. Parties in- 
terested in selling the “mine” procured bits of bituminous coal from a 


BUILDING MATERIALS. 93 


convenient blacksmiths’ shop, and strewed them in the soil near this 
opening. 


OcHRES. 


Bog-iron ores of the nature of ochre occur at Bow, Lancaster, Bedford, 
Amherst, Merrimack, Bath, Madison, Grafton, Lebanon, Barrington, Gil- 
manton, Mason, Lyndeborough, New Boston, Chesterfield, Nottingham, 
Orange, Pembroke, Salisbury, Jaffrey, Moultonborough, Orford, Surry, 
and Plainfield. One of the most extensive is upon the land of David 
Colby, in the west edge of Hooksett, where I saw a few hundred pounds 
of red and yellow paints that had been washed free from impurities and 
prepared for the market. The material seemed to be sufficiently abun- 
dant to be utilized. I have not seen the ochre manufactured into paint 
elsewhere in the state. 

The other articles enumerated at the outset, viz., copperas, alum, titan- 
ium, and moulding-sand, can be obtained from various localities. The 
first could be manufactured at several localities in the Connecticut val- 
ley, though not so as to be able to compete successfully with the works 
upon Copperas hill. 


CHAPTER, IF. 
NATURAL FERTILIZERS. 


Yen rocks of New Hampshire are largely granitic or feldspathic. In 
decomposition an abundance of potash is liberated, together with 
variable quantities of soda and lime. But our soils invariably show a 
small percentage of phosphates universally distributed. As crystals of 
apatite are uncommon, the question has often arisen in my mind, Whence 
is this salt derived? We cannot believe that enough animals have left 
their skeletons during the later periods, when the present soil was in 
the process of formation, to explain the commonness of this essential 
ingredient. If not of animal, it must have been of mineral origin. 

The statement has been made by prominent agriculturists, that our 
rocks generally contain phosphate of lime. One of the points aimed at 
in the microscopic study of our rocks has been a search for apatite, under 
the impression that the soil phosphate must exist in minute crystals, in- 
visible to the naked eye. Our researches have shown the presence of 
this mineral in rocks from every part of the state. This fact gives us 
confidence in the ability of our underlying formations to furnish from 
age to age a plentiful supply of this salt, so essential to the growth of 
crops. 

Part IV contains numerous incidental references to the localities of 
microscopic apatite. I will enumerate the instances there mentioned, 
presuming that they are much more abundant than are here indicated. 
It occurs in the porphyritic gneiss of Antrim, the ancient gneisses of 


NATURAL FERTILIZERS. 95 


Westmoreland, Grafton, and Swanzey, various mica schists, the quartz 
schists of Portsmouth, the Huronian of Norwich and Hanover, the gab- 
bro of the White Mountains, the diabases of Bemis brook and Rye, the 
augite sienite of Jackson, the sienites of Chatham and Red hill, the dio- 
rites of Campton, Stewartstown, and Dixville, and the granite of Rye, 
Concord, Colebrook, Lightning mountain, Jackson falls, and the coarse 
veins carrying the valuable masses of mica and feldspar. It is found, 
also, in the porphyry of Waterville and Albany, and in the town of Pier- 
mont. 

The other natural fertilizers of importance are limestones and the vari- 
ous forms of peat. The first have been described already in the preced- 
ing chapter. It is astonishing that our farmers so entirely neglect the 
abundant supplies of limestone occurring in our midst, and either fail to 
procure this mineral, when required for their soil, or else purchase that 
which has been brought hundreds of miles. 

Only two beds of calcareous marl are known in the state,—at Hollis 
and Columbia. Both are limited in amount, while the substance itself 
is of excellent quality. 

Two and a half miles south-east of Colebrook village, in the north part 
of Columbia, is Lime pond. This pond is nearly a hundred rods long, 
and probably half as wide. Its bottom is covered with white calcareous 
marl, which has a depth in some places of 15 feet. On the east side of 
the pond there is also a buff-colored sedimentary deposit. 

The marl is formed by the accumulation of myriads of shells of the 
Cyclas and Planorbis, an abundance of which was everywhere found where 
the marl was covered with water, for the pond has been partially drained. 
Dr. Jackson supposed the neighboring peat swamp to be the most active 
agent in supplying the shell-fish with calcareous salts, from which they 
secrete the carbonate of lime of their shells. ‘On testing the water, it 
was found to be charged with crenate, apocrenate, and humate of lime, 
and it contains, also, a notable proportion of ammonia. In evaporating 
a portion of the water, a buff-colored precipitate subsides, which contains 
the above-mentioned organic acids, combined with lime and an excess of 
carbonate of lime, which was originally held in solution by carbonic acid 
as a bicarbonate.” 

Peat is the vegetable soil of bogs and swamps, and consists of the 


06 ECONOMIC GEOLOGY. 


débris of decomposed aquatic or marsh plants. That formed from moss 
is of the best quality, and it is very abundant in the granitic regions of 
the northern United States. Muck is peaty matter mixed with soil, and 
is consequently less valuable than the pure article. Peat ripens with 
age or advancement in decomposition, and is thus comparatively heavy 
and dense, and appears pitchy. Its value increases with age. This sub- 
stance may make a good fuel; but especially it is susceptible, under 
proper treatment, of becoming a valuable fertilizer. It absorbs and re- 
tains water and ammonia, promotes the disintegration of the rocks, ren- 
ders light soils more productive by its application, and acts as a direct 
fertilizer. 

Those who have experimented with this material, and compared its 
properties with those of ordinary stable manures, find that it usually car- 
ries, in a given amount, one third more organic matter, an equal amount 
of lime and nitrogen, but is deficient in potash, magnesia, phosphoric and 
sulphuric acids. These deficiencies may be remedied by adding to 100 
pounds of fresh peat one pound of commercial potash, or five pounds of 
unleached wood ashes, one pound of good superphosphate, or one pound 
each of bone-dust and plaster of Paris. In view of the small amount 
and the cheapness of the materials to be added to peat to make it equal 
to stable manure, it seems as if the farms of New Hampshire might be 
greatly enriched at a very small expense. The peat of various localities 
requires different degrees of amendment; and therefore only the general 
rule given above can be stated to show what ought to be done. Samples 
should be sent to a chemist for special analysis by those who wish to 
utilize the article. 

Without speaking exhaustively, we have a few notes about peat in dif- 
ferent localities, which may be of service in giving some idea of the great 
abundance of the deposit in every section of the state. The facts from 
the extreme north were furnished by Mr. Huntington, and others are 
copied from Mr. Upham’s note-book. 


Bogs and peat swamps are very numerous in northern New Hampshire. They are 
found in every town, and are often of great extent. Sometimes they present a broad 
area, without the vestige of a tree or shrub, except along their borders, and this area 
is covered with a luxuriant growth of grass (Calamagrostis Canadensis). One of the 
largest of this kind is a mile and a half west of Second lake, at the head of Bay brook, 


NATURAL FERTILIZERS. 97 


‘and it has an area of fifteen or twenty acres. West of Perry Stream, on the same 
line going west, there is another extensive bog; and also northward, near the head of 
the same stream, there are several. These are more or less occupied by shrubs and 
trees. The laurel, Kalmia glauca, labrador tea, and the Ledum palustris, are common, 
while here and there, from the sphagnous bed, rises a,hackmatack or larch. Northward 
of Second lake, towards Mt. Carmel, there is a very extensive swamp, but there are no 
open bogs. Here, besides the laurel, the labrador tea, and the larch, we frequently 
find the cedar and the alder. Half a mile south of the south bay of Connecticut lake 
there are two small open bogs; and on these cranberries are abundant. These bogs, 
like those north, seem to have been formed almost entirely from a species of moss 
(sphagnum). The peat here is not more than six feet in depth, and for the most part 
it seems to be composed of partially decomposed fragments of the moss. 

Organic acid produced by the vegetable matter, when long saturated in water, re- 
moves from the subsoil of the bogs the oxides of iron and manganese, as well as lime 
and other alkaline earths: hence the subsoil of bogs usually consists of bleached whit- 
ish sand and clay of a very unproductive character. There are few exceptions to this, 
in localities where the soil contains a very large proportion of lime. On the other hand, 
when the underlying rocks contain an iron sulphide, the sulphuric acid produced from 
this mineral gives a still greater degree of acidity to the bog, while the iron is some- 
times in too great quantity to be entirely removed. ‘‘The iron and manganese, re- 
moved in the manner above mentioned, are deposited, usually, in rounded kernels at 
the outlet of such bogs, or in the soils through which the water soaks, and become 
partially exposed to the air. In this way small quantities of bog-iron ore and bog man- 
ganese ore are formed in the vicinity of many swamps. All these facts respecting bogs 
have their analogies on a large scale in our ancient rocks.” ‘‘The bogs, when drained 
and their surfaces dressed with sand or sand and lime, to supply the siliceous and calca- 
reous matter in which they are deficient, are excellent soils, second only to dyke marshes 
in their productiveness in hay and oats.” There are many bogs in northern New Hamp- 
shire that might in this way be reclaimed, as it is not improbable that in time the peat 
from the swamps will be used as fuel and asa fertilizer. One of the most extensive 
swamps in the state is in the south-east part of the Dartmouth College grant. The dis- 
tance across this bog on the state line is 290 rods, and the distance east and west, in- 
cluding the bogs on both sides of the Magalloway, is much greater. Along the Andros- 
coggin there are several interesting peat deposits. One in Milan, just north of the 
mouth of the Chickwolnepy, has in it many trunks of fallen trees, principally tamarack 
(larch), nearly all of which are well preserved. In Shelburne, on the farm of Mr. Bur- 
bank, is a peat swamp that has been partially reclaimed. 

The peat lands of Rochester, probably more than 150 acres in total amount, are well 
seen from the Portsmouth, Great Falls & Conway Railroad. The deepest soundings 
in these bogs, found by the railroad survey, were a little more than 20 feet. Between 
the village and the first crossing north is the most extensive single area. Here 50 to 60 
acres, upon which the peat is 5 to 15 feet deep, situated on the east side of the railroad, 

VOL. V. 13 


98 ECONOMIC GEOLOGY. 


are owned by the Strafford County Improved Peat Company. This company was incor- 
porated during the civil war, when the price of coal was greatly advanced. After the 
war, coal was again cheap, so that it was thought impossible to prepare peat for the 
market at a profit, and no work was ever done by the company. Mr. E. J. Mathes has 
used this peat two or three years as fuel for his house. It is cut with a spade shaped 
like the Irish slane. The pieces are spread to dry, for which they need to be turned 
over after two or three days. In this way the water, to the extent of 75 per cent. of 
their original weight, is evaporated, and they shrink one third in size. Thus prepared, 
the peat is very spongy. A better process, also employed by Mr. Mathes, is to grind 
the peat and break up its vegetable fibers, in the manner that clay and sand are mixed 
for brick-making. Thus ground and moulded like bricks, pieces 4 by 6 by 8 inches in 
dimension shrink in drying to 2 by 4 by 6 inches, or to one fourth their original size. 
The peat thus prepared is compact and hard, requiring a hammer to break it. It yields 
a considerable amount of ashes, which are very light and dusty. They are found use- 
ful for polishing. 

Several peat-bogs occur in Stratham. The largest is the Temple meadow in the 
south-east part of the town, covering 60 acres, the depth of peat averaging about 4 feet; 
its greatest depth is 6 feet. This peat has never been used. Another peat-swamp, 
occupying about Io acres, lies one mile north of the village. This was used for fuel 
to some extent about fifty years ago. Its only use now is as a manure, for which about 
too cords are dug yearly. About half a mile east from the last is the Heath swamp, 
containing about roo acres of peat. This was never used for fuel. About 50 cords are 
employed yearly for manure. The depth of peat in these swamps exceeds 20 feet. 

Other localities, where peat is conspicuously abundant, are South Lancaster, Spring- 
field, Grantham, Enfield, Lebanon, and many others in Rockingham, Strafford, Hills- 
borough, and Merrimack counties. 


INDEX. 


IN DEM TO PART V, 


Page. 

Allen, J. H. 8 
‘* mine, . 21, 26 
Alluvial gold washings, 27 
Amalgamators, é 13 
American Tin Company, . 67 
Ammonoosuc district, zee of . 35 
oe gold field, 7 
Analyses of limestones, - 85 
“ iron ores, - 62 
Ankerite, : - 2 
Apatite in rocks, - 94 
Arsenic, . . 68 
Arsenical pyrites, 26, 68 
Atwood gold mine, . 8, 26 
Auriferous conglomerate, - 20 
Banks lead mine, . 63 
Bartlett iron mine, . - 37 
Bedell gold mine, 19, 33 
Bennetts, Capt. 33, 43 
Bismuth, ‘ - 68 
Bog-iron ore, . 5 93 
Bowers’s mica quarry, 90 
Bricks, where made, 2 86 
Brick clay, Fi . 86 
Building materials, . 70 
Burke lead mine, 63 
Chimneys in quartz veins, - 9 
Chubb separator, . : 5 » 44 
Cleaveland, J. W. . . 5 “ 28 
Concentration of ores, . 43 
Concord, granite in + 70 
Cook and Brown mine, 20, 25 
Copper, ‘ 37 
“« veins, nature of . 38 


‘* in southern New Hampshire, 


49 


Page. 
Crosby process, 26 
Croydon mine, 50 
Discovery of gold, 8 
Dodge auriferous vein, II 
‘« Gold Company, 8 
Edgar, Capt. . P . 25,49 
Electro Gold Company, : é 10, 13 
Feldspar, A . 88 
F feepilliam polishing powder, 92 
Flags, . 82 
Fogg mine, 47 
Forsaith mine, 37 
Franconia mine, 56 
Galena in auriferous quartz, » 33 
Gardner Mountain Company saa 
38; map one 3 - 36 
Glass, 88 
Gold, 7 5 ; 4 
‘© amount of, mined in N. H., II 
‘* Ammonoosuc field, 2 7 
‘« mining, profitable, . 28 
ae “© cost of 30 
«« in conglomerate, 20 
«* in Enfield and Canaan, . 4 
‘“* in Quebec, 5 
“*  sulphurets, 23 
s¢ quartz, @ Il 
on Indian stream, : 5 
‘© quality of 12 
Gordon mine, . 2I 
Grafton company, 22 


102 


INDEX TO PART V. 


Page. 

Grafton fertilizer, 22 
Granite, . 70 
a worked in Brunswick, Vt., 79 

ae Columbia, 73 

ee ad Concord, 71 

ss as Farmington, 78 

ee fe Fitzwilliam, 75 

ee ee Hanover, . 80 

se ee Haverhill, . 78 

es as Hooksett, . 73 

ee ae Lebanon, . 79 

es ne Manchester, 77 

ss es Marlborough, 76 

es as Mason, 77 

hs Hie Milford, 74 

« ee Nashua, 74 

ss es Pelham, 73 

«s “6 Plymouth, 77 

He i Roxbury, . 76 

oe es Ryegate, Vt., 79 

se es Salem, 73 

#8 ie Stark, 79 

as ee Sunapee, . 78 

as es Swanzey, . 77 

“cc 6c Troy, 76 
Gregory Copper Co., 39 
Hartford mine, 19, 33 
Haviland mine, - 40 
Hoyt lead mine, .. 63 
Hunt, T. Sterry, letter from 54 
Hunt & Douglass process, . «2 
Huntington, J. H. . 5, 48, 57, 96 
Iron ore, . , . 56 
us localities of 61 

“8 mountain, 57 

se in Bartlett, < 57 

ee in Lisbon, 56 

se in Piermont, 60 

ce in Winchester, 61 
Jackson, C. T., 56, 58, 62, 66, 68, 84, 95 
Kilton & Sargent quarry, go 
Lang copper mine, . 46 
Lead tradition, . 62 
in Hooksett, . 65 

‘* in Loudon, 65 

‘* in Madison, 62 

‘* in Rumney, 65 

‘* in Shelburne, 64 

‘© in Woodstock, 65 
Limestone, . 3 : 82 
“ in Haverhill, 82 


Page. 
Limestone in Lisbon, « 83 
ae in Littleton, . 84 
“s in Lyme, - 83 
“s in Orford, . 83 
fe as res ‘ - 95 
Lime pond, . 85,95 
Lisbon Gold Co., 8, 26 
Lyndeborough quartz, . 89 
Map of Ammonoosuc district, . 35 
‘« Gardner mountain, 36 
Manganese, 68 
Marl, . 95 
Martin & Page quarry, 90 
McClintock, J. N 36 
Mellen’s quarry, go 
Merrimack silver mine, 34 
Metals and their ores, 3 
Mica, “ * 89 
‘“« in Grafton, go 
Molybdenum, . 68 
Natural fertilizers, . 94 
Neal mine, 51 
Newburyport mines, . 34. 
New Hampshire Silver Lead Co. es 32 
Newmarket mine, 34 
Novaculite, 92 
Ochres, 93 
Oilstones, 92 
Paddock, J. H. 32, 44 
ee company, - 42 
ils galena, 32, 33 
a mill, - 44 
Parker, Willard - II 
Peat, 95; how amended, - 96 
Phosphates i in rocks, - 94 
Pittsburg mine, a. OE 
Plumbago, - gf 
tag penne, - Of 
Pope, J. H ‘i 6 
Pottery, . ‘ . 88 
Precious stones, - 9! 
Pyrrhotite in granite, « 80 
Quartz, not auriferous, 4 
Quint mine, 3 46 
Rae, Dr. J. H. A é . - Io 
$6 ss patents, 13; process 
in Virginia, . 17 


Ruggles mica quarry, 


INDEX TO 

Page. 

Seely, C. A., analyses by, + 20, 32, 47 
3 50, 63 
Silver, . 32, 41 
Silverdale mine, ‘ 65 


Slate, 81; in Littleton, 8; in East 
Lebanon, . 

Soapstone, 86; in Canterbury, 87; 
in Haverhill, 88; in Francestown, 
86; in Orford, 885 in ees By : 


82 


in Weare, 87 
Stevens, Dr. R. P. - 34 
s¢ mine, 33, 41 

St. Johnsbury Granite Co. i - 79 
Sulphuric acid, : 49 
Sulphurets, gold i in. 23 


PART V. 


Sumner mine, . 


Tin, 
Twitchell & Mason mine, 


Umbagog Lake polishing powder, 
Vinton, F. L. . 


Warren mine, . 

White Mountain granites, 
Worcester mica quarry, . 
Wurtz, H. 3 : 


103 


Page. 
47 


66 
47 


g2 

34 
25, 48 

80 


90 
g, 32 


ERRATA. ., 


Part III. 


On page 167, line 6 from the bottom, for ‘‘ Plate IV,” read Plate V//. 

On page 184, line 5, for ‘‘ Bronson hill,” read Bronson's kiln. 

On page 184, line 13, for ‘*S. 28° E,” read S. 28° W. 

The same upon page 212, line 20. 

On page 187, line 16, ‘‘ Mrs. M. Gale’s” should be placed under Belmont. 

On page 187, line 35, ‘‘ K. Hall's” should be placed under Gilford. 

On page 187, lines 4 and 5 from the bottom, for ‘south corner,” read Strafford Cor- 
ner. 

On page 188, last line, for ‘‘ Newbury,” read Sutton. 

On page 189, line 15 from the bottom, ‘‘E. C. Sanborn’s” should be placed under 
Hampton Falls. 

On page 194, lines 6 and 7 from the bottom, ‘‘ Lufkin’s and Howe’s” should be placed 
under Rumford. 

On page 202, last line, insert ‘‘ not” before distinguishable. 

On page 203, line 11, for ‘‘ south-east,” read south-west. 

On page 302, first line, for ‘‘ rounds,” read mounds. 


Part IV. 


On page 8, line 8 from the bottom, for ‘‘ clacite,” read calcite.’ 

On page 80, line 7 from the bottom, for ‘‘ Fig. 2 on Pl. 9,” read Fig. 9 on Fl. 2. 
On page 102, in the formula, for ‘‘Al,” read A/?. 

On page 15, and elsewhere in the first chapter, for ‘‘ pinnacoid,” read pénacoid. 


PART V. 


On page 44, line 7 from the bottom, and page 45, line 26, for ‘‘slums,” read s/zmes. 


a deal eh 4 aeatag Petite 
Sev diana og yt Rone Pre ipaeuts its ih 
TNt ay " Ce eas 

( 


Lian ehasterbepenen 
mee gtahichat 
ferent 


ele 


jeter Gon ate gun ate Pak mare feted 
Dis cer pain aoe Belz tie tate he lot Hiei * 
eo degourcneatit ‘ i ‘ ‘ if 
ie ease « hs e Sie He ay" aie ped UM i 
; i y Nahai: oben Hing ae ia) italy ‘ 


Lp apple neci lear ae isa Poe 
wee eee yt 
sie \ ape iis 


: ; sieges ‘ ints eh sy 
“ithe ft ae rds 
petetabeet ote eff be 4 . 
Sees = eet ees aeeiaie Bet a be ie 
oo sting i ft SSN ANAL A keen tAeacicany Manse analy y eh 
Shea: tenthcacicns gia Has ui Ally 
AY 


ieiayatis 
Ree Aes ies 

Wag yt iss 

Ai Oni oy alias ts, 

Lee HN “ise tg Liar y 


Hyely ry 

We ata Msg 
4) ie is 
" aN 


ohio 
cage apes 


assent 


Seng 
LL vite 
La 

‘ 

4 


ran 
at bal Aho tit 
eet oe is 


aban 


eee 


* ie 
Pita ale Ae Paks 


a Saha tay! * 
Ph pln i nd ane eee 


oe Pe 
Sense con a sherri ase 


id a ae "athens, We fe 
vif an A 
Reem ne ie 


see ons Serna t eta 
a eee See naa 
oe ee 


Fae mE (my 
ere a : oe ‘ ‘ 
‘4 paneer: Sopa coca 
Ener a 
<a 


chancery i 


Aa 
Seicin as Sipura aioae Sh aS mite 
elena aya yee) 
Pct peat: et st mb a a ri meg i 
i hee taney M st 
Cigna ieteeoa == tetas waa ee ia i 
ifs Cy a Ns 
Mista ‘ ieeyheirer Ws 
tee i Ne 


vainly Soran 
SS paar ee usta setae at 
a ean ele 
erect Kh m0 Fs WLAN aa 
Ss Ppisicraser iene et ia fi iS 
ot eee Whi 
ay ac braced a tarsal iy sioid I wali ay 
Herter ¥ 
=. ae A te wink wna pewey nat ae 
Saami 
Seniors Re mre haan 
cee ere tueraruta ts nh 


alan 


SE Reet Bont ten 
ieee Spee 
tas 


ne ihe 
ea at ba Tien 


Pitt ee TESURR A 


Sean enna 
— ae cree y ees re = 4 Nt ek 
meee a Seema it ‘ USAR R TAN 

one janice 


eecaenn era Venetes 
ucsieue igen SLL AES atta RON 
SS srcrareenreest a a se tater sara : ; ea east 
asst “ fe i ivr eree dl H ean A 
ie ne 
“f Ah 


— 


y “ 
mene 
eaters ee Laat 
a ete ty mie 
iti aot ans 
Baan haa 
i 
Shoe