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UNH LIBRARY

3 MbOD DllEE bfli

THE GEOLOGY

NEW HAMPSHIRE

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

C. H. HITCHCOCK,

State Geologist.

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

Assistants.

PART II. STRATIGRAPHICAL GEOLOGY.

CONCORD:

EDWARD A. JENKS, STATE PRINTER.

1S77.

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PREFACE.

Nearly two years and a half have been occupied in the compilation and
printing of this volume. Material additions to our knowledge of the rocks,
consisting of two summers' field-work, have often corrected, improved, and
added to the statements already printed. This has been the most marked in
the White Mountain district. Mr. Huntington has performed an excellent
work, in his chapter upon the Coos and western Merrimack districts, particu-
larly in distinguishing the coarse granite belt and the fine-grained division of
the Bethlehem gneiss, the first being of practical consequence in determin-
ing the best places to work mica quarries. We have constantly endeavored
to state all facts in the briefest possible language ; and, in consequence of the
immense number of observations recorded, the last four chapters have been
much abbreviated. In spite of all our cfibrts, the subjects of Surface Geol-
ogy, Economics, Mineralogy, and Lithology are crowded out into a third
volume, nearly a hundred pages of which are already printed. Mr. Warren
Upham has undertaken the description of the Modified Drift ; and Mr. Geo.
W. Hawes will discuss Mineralogy and Lithology. Both these treatises will
be of rare value. We have undertaken the collection of several sets of speci-
mens illustrating our Lithology, each consisting of two hundred and fifty
varieties. These may be found at the college museum, at the state house,
and at the normal school. Other sets are on hand for exchange or sale.

The study of the topography of the state has not ceased with the publica-
tion of Part L Our labors have been unexpectedly successful, so that we
shall present upon the geological map contour lines for every hundred feet
throughout the state. These lines will not interfere with the coloring repre-
senting the distribution of the formations, but will the rather aid in under-
standing their relations to mountains, plains, and valleys. We have also

IV PREFACE.

constructed a model of the state, about fifteen feet in length, on the scale of
one mile to the inch horizontally, and one thousand feet to the inch verti-
cally. Copies of this model are to be found at Concord and Hanover. It is
our belief that this topographical model is one of the most important prac-
tical results of the survey. Special attention is called to the unique method
of arranging rocks, in relation to geography and structural geology, described
in Chapter IX.

Arrangements have been made for the publication of our geological map,
upon the scale of two and a half inches to the mile, in the best style, by Julius
Bien, of New York. The engraving is completed, and it only remains to
execute the coloring. We had hoped the sheets might be ready for distribu-
tion with this volume. Most of the descriptions refer to the map, so that
they cannot be thoroughly understood without it.

C. H. HITCHCOCK.
Hanover, May 12, 1877.

TABLE OF CONTENTS.

Chapter. Page.

I. THE RELATIONS OF THE GEOLOGY OF NEW HAMPSHIRE
TO THAT OF THE ADJACENT TERRITORY.
By C. H. Hitchcock, 3

II. GEOLOGY OF THE COOS AND ESSEX TOPOGRAPHICAL DIS-
TRICT.
By J. H. Huntington, 37

III. GEOLOGY OF THE WHITE MOUNTAIN DISTRICT.

By C. H. Hitchcock, 98

(Pages 127-131, 148-151, by J. H. Huntington.)

IV. GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

By C. H. Hitchcock, 271

(Pages 408-427 by J. H. Huntington.)

V. GEOLOGY OF THE MERRIMACK DISTRICT, WEST PART (the
gneissic area from LandafFto the southern boundary of the state).
By J. H. Huntington, 466

VI. GEOLOGY OF THE MERRIMACK DISTRICT, EAST PART.

By C. H. Hitchcock, 518

VII. GEOLOGY OF THE LAKE DISTRICT.

By C. H. Hitchcock, 592

VIII. GEOLOGY OF THE COAST DISTRICT.

By C. H. Hitchcock, 611

IX. DESCRIPTION OF THE GENERAL SECTIONS.

By C. H. Hitchcock, 634

X. CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS.

By C. H. Hitchcock, 658

INDEX, 677

LIST OF ILLUSTRATIONS.

ILLUSTRATIONS PRINTED WITH THE TEXT.

Fig.
Fig.
Fig-
Fig.
Fig.
Fig.

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

R. to

Geological map of North America,

Teschemacher's figure of crystals of tin ore from Jackson,

Section from the Androscoggin — line of Cambridge and Errol — to the

Maine line south of Umbagog lake, ....

Section from Stark water-station, G. T. R., to Milan,
Section from Leighton's mills, Dummer, to Rocky pond, Millfield,
Section from the south-east corner of Berlin, then along the G. T

the bridge west of West Milan,

Section from Northumberland falls to the Passumpsic river, Vt.,
Section across Mt. Monadnock, Vt., into Columbia,
Section from Northumberland falls to Pilot mountain,
Map of the Ammonoosuc gold field, ....

Section from Bronson's lime quarry to Smith's brook, Lyman
Section in Dalton and Whitefield, .....
Section through Swift Water village, ....
Section from Palmer hill through Burnham's lime quarry,
Section from Crouch's to Shute's house,

Section through the buhrstone,

Section along carriage-road westerly from Littleton village.
Section southerly from Fitch's house, ....
Section from quarry road to L. A. Parker's, .
Section from slate quarry to the Ammonoosuc river,
Section from Mulliken's brook to North Lisbon,
Section up South Branch, North Lisbon,

Section of distorted pebble, Lebanon

Rae's amalgamator, sheet i,

Page.

5

36

51

52

54

55
65
67
72

275
278

3^7
320
326
32S
328
329
33^
332
333
334
336
465
517

Vm LIST OF ILLUSTRATIONS,

ILLUSTRATIONS NOT PRINTED WITH THE TEXT.

[Figures within parentheses denote the page where the illustrations are described.]

Heliotypes from Nature.

- Page.

Frontispiece — Mt. Pequawket. Colored to show formations, . . . (236)

The Devil's Slide, 69

Mt. Lyon, 72

Crumpled strata upon Mt. Washington, two heliotypes, 119

Profile mountain and Eagle cliffs in Franconia, 139

Goodrich falls, Jackson, 146

Beaver falls, Colebrook, and Champney falls, Albany, .... (47) 150

Mt. Chocorua, 152, (232)

The Basin and Boulder overhanging the Flume, Lincoln, 157

Flume, Lincoln, 158

Hitchcock flume and Older breccia, 172,(169,242)

Mt. Willard, from Willey Slide, and Silver cascade, 177, (242)

Mt. Crawford and Lake of the Clouds, 183,(242)

Heliotypes and Direct Transfer Plates.

Page.

Plate I, Geological map illustrating the relation of the New Hampshire formations

to those of the adjacent territory, 8

Plate II, Section from Whitehall, N. Y., to Plymouth, Mass 15

Plate III, Section from Montreal, P. Q., to Portland, Me., 30

Plate IV, Section from Bourg Louis, P. O., to Mount Desert island, Me., . . 34
Plate V, Map showing locations of specimens collected in Coos county, . . 80
Plate VI, Fig. i. Section XIV, from Hall's stream across Second Connecticut

lake to the Maine boundary, 86

Fig. 2, Section from Sherbrooke, P. O., to Connecticut lake, N. H., . . (92)
Fig. 3, Section XIII, from the east part of Holland, Vt., to Maine, opposite

Academy grant, . (87)

Fig. 4, Section XII, from Charlestown, Vt., to Umbagog lake, . . . (88)
Fig. 5, Section XI, from Groveton to Maine boundary, in Success, . . (90)
Fig. 6, Section X, from Connecticut river in South Lancaster to Maine

boundary, in Success, (91)

Fig. 7, Section from Mt. Lafayette to Bald hill, Littleton, .... (99)
Plate VII, Map of the carriage-road upon Mt. Washington. Section through Mt.

Washington, from the Glen house to Ammonoosuc station, (116, 241)
Fig. 17, H. D. Rogers's map of Notch valley, .... (189)

Plate VIII, Fig. 10, Old Man of Dixville, 134

Fig. 20, Junction of Montalban gneiss with Labrador system, Mt. Wash-
ington river, (218)

LIST OF ILLUSTRATIONS. ix

Page.

Fig. 19, Structure of Tripyramid mountain, (214)

Fig. 13, Section from Lower Ammonoosuc river to Mt. Hale, . (144)

Fig. 12, Section from "West Tliornton to Welch mountain, . . (135)

Fig. II, Section from soutli-east Dalton tlirougli Whitefield and Carroll, (no)

Plate IX, Fig. 16, View of Mt. Willard from Silver cascade, . . . .171

Fig. 14, Remains of structure in granite at Goodrich falls, . . (146)

Plate X, Fig. 15, Section from Tin mountain to Hancock mountain, . . (146)184
Fig. 22, Top view, Fig. 23, Side view, and Fig. 24, Bottom view of

boulder from Bemis brook, (182,241)

Plate XI, Illustrations of the Pemigewasset granites, 230

Fig. 18, Vein of sienite in labradorite, Tripyramid mountain, . (215)

Fig. 21, Rocks about Cuttingsville, Vt., (231)

Fig. 25, Section from Mt. Lafayette to Mt. Tom, .... (260)

Fig. 26, Section from north-east corner of Tamworth to White's ledge, (261)

Plate XII, Map showing locations of specimens and dip of the strata in the White

Mountain district, .......... 242

Plate XIII, Sections across the Ammonoosuc gold field (Figs. 29-33), . . 288

Fig. 29, From Bath lower village to Connecticut river, . . . (285)

Fig- 33> From Blueberry mountain in Littleton to Albee copper mine, (290)
Fig. 32, From Young's pond, Lyman, to North Monroe, . . (289)

Fig. 31, From Ammonoosuc river above Lisbon village to the Oro mine

(misprinted 32 in text), (287)

Fig. 30, Along Smith brook, Lyman, from school-house to Mclndoe's Falls, (286)

Map of the south-east part of Lyman, 296

Plate XIV, Sections illustrating the Huronian, 35S

Fig. 45, Section near north lines of Newbury, Vt., and Haverhill, , (356)

Fig. 46, Section from Hall's brook, Newbury, Vt., to limestone quarry

in Haverhill, (349)

Fig. 47, Section from Hedgehog brook, Newbury, Vt., to East Haverhill, (358)
Fig. 48, Section from north-east Bradford, Vt., to Webster Slide mountain, (380)
Fig. 49, Section from Bradford, Vt., to Piermont mountain, . . (381)

Plate XV, Sections in Connecticut valley, 385

Fig. 36 a, Revision of Fig. 36, (327)

Fig. 50, Section from Soapstone mountain to Pine hill, Orford, . (381)

Fig. 51, Section from Orford street to Mt. Cuba, Orford, . . (382)

Fig. 52, Section from Connecticut river to Bear hill, Orford, . . (384)

Fig- S3, Section through North Lyme, (384)

Fig. 54, Section from Strafford brook, Thetford, Vt., to east part of Lyme, (385)
Fig- 55. Section from Union Village, Vt., to Bliss pond, Lyme, . (387)

Fig. 56, Section from Pompanoosuc station, Vt., to Moose mountain,

Hanover, (355, 388)

VOL. IL II.

X LIST OF ILLUSTRATIONS.

Page.

Plate XVI, Sections in the Connecticut valley, 397

Fig. 57, Section from Connecticut river to Baptist church, Hanover, (355)

Fig. 58, Section from Ledyard bridge, in Hanover, to Moose mountain,

(355, 361, 388)
Fig. 59, Section from White River Village, Vt., to Craft's hill, Lebanon, (362)
Fig. 60, Section along the Mascomy river in Lebanon and Enfield, (389)

Fig. 61, Section in the south part of Lebanon, .... (392)

Fig. 62, Section from Windsor, Vt., to Croydon mountain, . . (397)

Fig. 63, Section through Claremont, (398)

Plate XVn, Sections in the Connecticut valley, 425

Fig. 64, Section from the Devil's Gully, Charlestown, to height of land

on the Langdon road, (4^5)

Fig. 65, Section from Rockingham, Vt., to Kilburn Peak, . . (4^7)
Fig. 66, Section from David Burnham's to Capt. C. N. Clark's, Charles-
town, (422)

Fig. 67, Section across Mt. Wantastiquit to the summit of Bear hill,

along the north line of Hinsdale, (423)

Plate XVIII, Map of the Helderberg area, from Brattleboro' to Bernardston, . 428

Plate XIX, Sections illustrating the Helderberg area, 428

Fig. 68, Section in rocks at Brattleboro' depot, .... (433)

Fig. 69, Section along Broad brook in Guilford and Vernon, . . (434)

Fig. 70, Section through central Vernon and Hinsdale, . . . (434)

Fig. 71, Section along state line from Winchester to near Fall river, (438)
Fig. 72 (misprinted 71 in text). Section from south-west base of Bald

mountain to Grass hill, south-east corner of Bernardston, (444)
Fig. IZi Section on Williams hill, Bernardston, . . . (444. 454)

Fig. 74, Section from Williams hill to north part of Gill, . . (454)

Plate XX, Sections by J. H. Huntington, 476

Fig. 76, Section from the west side of Fifield hill to Unity centre, . (413)

Fig. ']'], Section from hill west of school-house No. 13, Westminster,

Vt., to Langdon village (410)

Fig. 78, Section from Hill village to C. Butterfield's, Westmoreland, (486)
Fig. 79, Section from S. Gordon's to J. Williams's, . . . (476)

Fig. 80, Section through Surry summit, Cheshire Railroad, . . (508)

Fig. 81, Section in Keene, across West mountain and Ashuelot valley,

(426, 508)

Plate XXI, Sections in porphyritic gneiss, ........ 525

Fig. 82, Section between two main ranges of porphyritic gneiss, . (521)

Fig. 83, Section from East Enfield to Danbury (521)

Fig. 84, Section across the porphyritic gneiss in Wilmot, . . (522)

Fig. 85, Section from Lovewell mountain to Bear pond, Warner, . (523)

LIST OF ILLUSTRATIONS.

XI

Page.

Fig. 86, Section from Millville, Stoddard, to Riley mountain, Antrim, (525)

Fig. 87, Section from South Weare to Manchester, . . . (544)

Plate XXII, Sections across Lake gneiss, 545

Fig. 88, Section from New Boston to Bedford over the Uncanoonucs, (545)

Fig. 89, Section from New Boston to the south part of Bedford, . (546)

Fig. 90, Section from South Lyndeborough to Milford, . . . (54^)

Fig. 91, Section from Temple to Brookline (547)

Fig. 92, Section in Manchester, (55^)

Fig. 93, Section in Derry and Salem, (561)

Fig. 94, Section through New Ipswich, (574)

Plate XXIII, Sections illustrating Merrimack district, 578

Fig. 95, Section from north-west Alexandria to New Hampton centre, (567)

Fig. 96, Section through Bristol and Sanbornton to Northfield, . (578)

Fig. 97, Section through north part of Deering, .... (575)

Fig. 98, Section from Townsend to Groton, Mass., . . . (585)

Fig. 99, Section in Belmont and Gilmanton, (578)

Plate XXIV, illustrating Merrimack and Lake districts, .... (587)

Fig. 100, Section through Derry, ....... (581)

Fig. loi. Curvatures in the strata— Mt. Kearsarge, . . . (586)

Fig. 102, Section through Mt. Kearsarge, (586)

Fig. 103, Section in Andover, (587)

Fig. 104, Section through Sandwich, (S97)

Fig. 105, Section from Sandwich to Wakefield, .... (597)

Plate XXV, Sections illustrating Coast district, 625

Fig. 106, Section from Pawtuckaway pond to Exeter village, . . (625)

Fig. 107, Section from Brentwood to Seabrook, .... (625)

Fig. 108, Section from Milton Mills to Alfred, Me., . . . (626)

Fig. 109, Section from Salem to North Andover, Mass., . . (626)

Fig. no. Section from Chesley mountain, Farmington, to Rochester, (626)

Plate XXVI, Principal axial lines in New Hampshire and Vermont, . . . 672

CHARTS IN THE ATLAS ILLUSTRATING VOLUME II.
Map of the Ammonoosuc gold field.
Geological map of New Hampshire, in six sheets.

PART II.
STRATIGRAPHICAL GEOLOGY.

CHAPTER I.

THE RELATIONS OF THE GEOLOGY OF NEW HAMPSHIRE TO THAT OF
THE ADJACENT TERRITORY.

BEFORE discussing the particulars of the geology of New Hamp-
* shire, it will be desirable to recall the general features of the
geological structure of the continent, in order to properly understand
our place upon it. Next, we shall turn our attention to the physical
characteristics of that particular section of which we find ourselves an
important component; and then examine more minutely the various
groups of strata peculiar to our district. It will be to the latter topic
that we shall devote the most attention.

Continental Subdivisions.

North America is rudely triangular in shape, with its most prominent
mountain ranges adjacent to the eastern and western borders, the latter
being the broadest, highest, and opposite the larger ocean. The rocks,
so far as needful for our present purpose, may be classified as the crys-
talline, two sets of sedimentary sandstones, limestones, and shales, and,
lastly, the loosely-coherent superficial formations occupying various basins
and water margins underlaid by the more compact ledges. These four
groups correspond in order with the Eozoic, Paleozoic, Mesozoic, and
Cenozoic systems of geological authors, the first being the oldest, or that
first reclaimed from the universal ocean.

In order to illustrate the relative positions of these four classes of

4 STRATIGR.\PHICAL GEOLOGY.

rocks, and the consequent method in which the continent has been grad-
ually built up, I have prepared a small geological map, which will exhibit
these mutual relations far better than words. The projection is the ordi-
nary one, exhibiting the surface as nearly as possible like nature, and not
distorting the northern regions so fearfully as Tvlercator's. The forma-
tions for the United States are copied in outline from the geological map
by W. P. Blake and myself, published in the supplementar}' atlas pertain-
ing to the ninth census, Gen. F. A. Walker, superintendent. The delin-
eation of the northern portion is taken mainly from a map by Robert
Bell, in Walling's topographical atlas of the dominion of Canada, and
from notes respecting Alaska, kindly furnished me some years since for
another purpose by W. H. Dall. As the scale is so small, the absence
of many considerable outcrops, especially in the Rocky Mountain region,
is a matter of necessity.

An inspection of our map will show a natural division into the follow-
ing grand districts, the most important being stated first, without regard
to age: i. The immense Rocky Tvlountain crystalline area, extending
from Alaska into Mexico. This is the foundation for innumerable minor
basins, which cannot be represented. 2. An equally extensive crystalline
area, embracing the north-eastern section of the continent, chiefly in the
territories of Canada, Labrador, and Greenland. This portion is rather
quadrangular in shape, with a central depression for the Hudson's Bay
Paleozoic area. 3. The interior Paleozoic basin, nearly divided along the
middle so as to separate between the arctic and eastern United States
regions. 4. A somewhat similar Mesozoic region lying to the west of
the preceding, and broadest southerly. 5. The elevated fresh-water Ter-
tiaries of the upper Missouri, and the marginal Cenozoic groups on the
Atlantic, Gulf of Mexico, and the northern waters off Alaska. 6. The
Atlantic belt of Eozoic formations. 7. Various local basins, as the Pale-
ozoic of Acadia and of the Colorado river ; the Mesozoic of Vancouver's
island, California coast range, of Utah and New Mexico, and of Alabama
and Mississippi; Cenozoic of Rocky Mountains, Greenland, etc. It is
the sixth of these districts that we shall call particular attention to
very soon.

I cannot resist calling attention to a very few points suggested by
this map : First. At the close of the Eozoic period the grand features

GEOLOGICAL RELATIONS. 5

of the North American continent were distinctly outlined, including the
Atlantic and Rocky IVIountain areas. The work of later geological pe-
riods seems to have been the filling up the bays and sounds between the

or

irORTH AMERICA.
I ms Xozorc

<■. ^ Afesozoic.

y|-p«^^]^-^>^\ ^ Cenozoic

great islands, elevating the consolidated mass into a continental area,
and probably submerging other equally important islands beneath the
Atlantic and Pacific oceans.

Seroml Although the Rocky IMountain Eozoic area existed very early,
it seems to have oscillated considerably during the Paleozoic and Meso-
zoic periods, sometimes elevated and often submerged, while the Eozoic
districts of the east remained elevated above the sea from the verj- first.
This is shown parti)' b}- the gradual extension westwards of the sub-
marine deposits. East of the I\Iississippi river there is scarcely anything
in the interior basin later than the coal measures. Then comes the

6 STRATIGRAPHICAL GEOLOGY.

development of enormous Triassic and Cretaceous deiDosits between the
long Paleozoic strip from Texas to the Arctic zone and the Rocky Moun-
tains, while along the latter region we fail to find the former groups to
any very marked extent, as would be expected were the western outcrops
steadfastly elevated at the same period with the eastern. If we may say
that the North America of Triassic times extended from Greenland and
the Atlantic ocean to Texas, we may also say that, by the close of the
Mesozoic, she had annexed to herself, by means of a specially constructed
causeway, the whole of the Rocky Mountain series of islands. Possibly
the genius of the continent is now looking forward to a similar absorp-
tion of the West India islands, through the filling up of the straits of
Florida and the intra-insular spaces.

TJiird. There were two promontories extending south-easterly from the
early continent, — one the w^ell-known Adirondack area, and the other the
metalliferous district near Lake Superior. The latter sent off a promi-
nent spur also towards the Laramie Mountains of Wyoming, projecting
eastwardly from the Rocky range. In fact, it is not unlikely that a bridge
connected these projections of land through the Black Hills during mid-
dle Paleozoic times.

FoM'tJi. The immense areas and the enormous thicknesses attained by
the Eozoic formations, especially in comparison with the later groups,
suggest that the earlier rocks have yet revealed to us very little of their
history. The later formations occur in comparatively thin incrustations,
easily studied and identified through fossils. The earlier groups are
much more difficult of identification, are best developed in the thinly
settled or absolutely wild districts, and hence have not yet assumed that
importance in stratigraphical columns which they are destined to receive
in the future. We trust, therefore, that geologists will not be too hasty
in deciding against the attempts of this volume to set forth the reality
of several new subdivisions in the Eozoic column of the Atlantic system.

The Atlantic Area.

In the chapter upon Topography, vol. i, p. 170, mention is made of
two sections of the mountains along the Atlantic, the first culminating
in western North Carolina, the second in New Plampshire. By referring
to Fig. I, I think it will appear that the Atlantic system should be

GEOLOGICAL RELATIONS. 7

extended to include the Eozoic area of Newfoundland, though separated
by the Gulf St. Lawrence. The lowest line between the northern and
southern sections reaches tide-water along Hudson river; and as the
disappearance of the Cenozoic margin at Cape Cod suggests a more
extensive depression of the land northerly, it is not strange that the
remotest section of the Atlantic area should be depressed more than the
others. There is a correspondence in the arrangement of the Newfound-
land formations with those of the adjacent provinces of New Brunswick
and Nova Scotia. The Paleozoic rocks of the north-west side of New-
foundland correspond with those of Gaspe ; the central gneissic area is
continuous from New Brunswick; and, not to mention all, the outer
Eozoic area of the outer Newfoundland island is the continuation of the
Nova Scotia Atlantic strata. Hence I believe a new classification is
possible, — that of the northern or Ne^^'foundland, the middle or New
Hampshire, and the southern or North Carolina sections of the Atlantic
range. The middle and southern will correspond with the northern and
southern sections of the Appalachian system, so ably set forth by Prof.
Arnold Guyot, in his memoir published in the Avierican yoimial of Sci-
ence and Arts, H, vol. xxxi, p. 157. The Appalachian system relates more
properly to the Paleozoic elevations to the west of the Atlantic chain,
the name having been improperly extended in application through false
theories of the age of the New England rocks.

In the southern section Laurentian areas are abundant. They are less
so in the middle district ; but I will now introduce a map and sections,
which will characterize the formations with considerable minuteness.

The Map.

Herewith is annexed [Plate i] a small geological map of New England,
with portions of the adjacent states and provinces. The territor}- includes
what might be termed the "Champlain island," or that portion of the
continent east of the Hudson valley which existed as an isolated district
for a long time after the Glacial period, the then submerged Hudson,
Champlain, and St. Lawrence valleys, and the remoter portions of Nova
Scotia, Cape Breton, and Newfoundland. It corresponds exactly with
the middle and northern section of the Atlantic belt, as defined above.
The lines were carefully drawn upon the scale of twenty-four miles to the

8 STKATKiKM'HICAr. GKOLOGY.

inch, and then reduced to alx)ut one hundred miles to the inch by pho-
tograpliy. Tlie area has ])ccn sufficiently extended to include all the
Canadian representations of the Labrador system. Outside of New Kng-
land, the geological boundaries have been copied from Logan's map of
1 869, as amended by Dawson's sketch of Nova Scotia and Prince Edwards
island, Prof. L. W. Bailey's and G. l\ Matthews's report upon New Bruns-
wick, and Alexander Murray's recent map of Newfoundland, The au-
thorities for New England arc my own maps and observations in the four
northern states, my father's map of Massachusetts of 1844, Pcrcival's
Connecticut, Jackson's Rhode Island, and a few isolated facts presented
by various authors. It is the first published attempt 'to subdivide the
crystalline and metamorphic formations of all this region.

Looking at the map in the most general way, a fourfold division natu-
rally suggests itself. Plrst, the more ancient gneisses and granites,
embracing the Laurentian, Atlantic, and Labrador systems. Second,
the immense areas of hydro-micaceous and micaceous schists, which arc
here termed Pluronian. Third, an equally great expanse of clay slates
and all the known fossiliferous groups of the Paleozoic. Fourth, the
comparatively restricted patches of slightly inclined areas of Mesozoic
and Cenozoic age. All these divisions possess characteristics peculiar to
New England, those of the first two being the ones most important to us
in the discussion of the geology of New Hampshire.

The first division is divided into four parts, — first and oldest, the
Lmirentian ; second, the Porphyritic gneiss and various undetermined
granites; third, the Atlantic; and fourth, the Labrado7'ian. The second
division cannot yet be well subdivided upon the map. The third consists
more largely of clay slates than anything else in the East, with all the
well determined Paleozoic formations of New York and Canada. These
slates arc grouped under the general term of Silurian and Cambrian of
the Atlantic area, in distinction from the same formation in the St. Law-
rence and Champlain valleys. These might be further divided, did the
scale of the map allow minuter representation. The outcrops of the
Devonian and Carboniferous are also distinguished from the preceding.
The fourth portion is easily divided into Triassic, Cretaceous, and the
capes and islands off southern New England, composed of Tertiary and
Alluvium.

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GEOLOGICAL RELATIONS. 9

Laurentiaii. Beginning at the south-west corner, we observe three
areas marked as of this age. Tlie greater one comprises the liighlands
of New York and New Jersey. Nearly all writers have agreed in this
reference, save that Prof. H. D. Rogers at one time regarded the crys-
talline limestones of New Jersey as metamorphosed Lower Silurian. Prof.
W. W. Mather separated from this "Primary" area various metamorphic
limestones and schists, thought to be of Silurian age, which are mostly
placed with the Atlantic system upon our map. Hall and Logan, in 1864,
found this so-called primary area in eastern New York to be the same
with what they had elsewhere called Laurentian.* Prof. Dana comes to
a similar conclusion.!

The two smaller areas to the north-east, partly in Connecticut and
Massachusetts, are Formations K 2 and K 3 of Percival, and are accepted
as Laurentian by Profs. Hall and Dana. The correctness of the bounds
of the latter area in Massachusetts may be open to question.

The large areas of Laurentian, in the Adirondacks and north of the St,
Lawrence river in Canada, are the exposures originally called by this
appellation by Sir W. E. Logan.

In New Brunswick this formation has been outlined in accordance
with the views of Bailey and Matthews.

In Nova Scotia, the metamorphic rocks accompanying the magnetic
iron ores of the Cobequid mountains and an extensive area running the
whole length of the peninsula, are referred to this period by Hugh
Fletcher, of the geological survey of Canada, in the topographical atlas
of the Dominion of Canada (1875), published with the approval of Mr.
Selwyn, the director of the survey. In accordance with the views of T.
Sterry Hunt, the latter area is placed in the Atlantic group.

The more central portions of Newfoundland, embracing more than half
its territory, may be referred to the Laurentian.

PorpJiyritic gneiss and undetermined granites. The importance of this
group in New Hampshire has been set forth to some extent in the first
volume. Upon the authority of the text of the Massachusetts report,
I have added an area between Worcester and the Connecticut valley.
There is probably another in Warwick. I cannot satisfy myself from
Percival's report that this formation occurs in Connecticut. The one

* Amer. Jour. Sci., II, vol. xxxix, p. 96. f I^i- HI. vol. iii, p. 255.
VOL. II. 2

lO STRATIGRAPHICAL GEOLOGY.

thus named by him near Bridgeport is hthologically iinh'ke the New
Hampshire rock, resembhng, however, a portion of our Bethlehem group.
In Maine, there is a small area midway between Rangeley lake and the
Kennebec river in the west, and along the Penobscot river at the granite
quarries. An unusually broad band of it lies between Bangor and Ells-
worth, represented in one of the long sections in this chapter. The other
areas are mainly of the undetermined granites. The largest is connected
with the porphyritic granite just mentioned, and it reaches from the
islands of Penobscot bay, or possibly St. George, to the Bay of Chaleur
on the Gulf St. Lawrence, a distance of 290 miles, and a width of from
two to twenty-two miles. That near New Bedford, Mass., is along the
same general line of outcrop. It is everywhere flanked by the Huronian.
In the neighborhood are the similar areas of eastern Hancock and west-
ern Washington counties. Me., and the one extending from Addison, Me.,
nearly to the St. John's river. A portion of this latter area is called
Laurentian by Bailey and Matthews in the New Brunswick report, and
they are all referred to this horizon in the topographical atlas of Canada.
Another important granitic area is that of Mt. Katahdin. Much of it is
surely not porphyritic, and is not unlike certain Labrador granites. As
all these granites are quite ancient, they are associated together in the
representation of their geographical positions, though not necessarily
identical in age.

Atlaiitic System. This system commences at New York city, and ex-
tends north-easterly through Connecticut, thence more northerly through
Massachusetts and Vermont, along the Green Mountain range into Can-
ada. Probably the Montalban and Lake groups are both represented,
especially in western Connecticut. The Green Mountain range has some
relation with the Montalban. The eastern Connecticut range branches
first to New Bedford, second to near Newburyport, third to Manchester,
N. H., and fourthly along the western part of New Plampshire continu-
ously to the White Mountains, and thence as far as the Androscoggin
lakes in Maine. From these lakes the presence of this rock is general
west of the Androscoggin river, west of the Kennebec and Penobscot
rivers, also below Augusta and Bucksport. Small areas exist at the
head waters of Dead river in Franklin county, in New Brunswick, and
Nova Scotia. The areas of this .system in Newfoundland arc not yet

GEOLOGICAL RELATIONS. I I

known with precision ; but it is likely that future investigations will add
to their present representation upon the map, at the expense of the Lau-
rentian.

Labrador System. All the known Labrador areas in eastern America
appear on this map. Five of them lie north of the River St. Lawrence.
One of the largest is situated a few miles north-west of Montreal, much
of it evidently concealed by the Lower Silurian groups. Next is a small
area bordering the St. Lawrence, on the Montmorency river, above the
falls. Its northern extremity is not over fifteen miles from the Murray
Bay area. A fourth is on the Saguenay river, below and east of Lake St.
John. The fifth is on the Moisie river, well towards Labrador. Still
another mass of labradorites has been recently reported in the south-west
part of Newfoundland. The Adirondack area is given as carefully as pos-
sible from Emmons's descriptions of his hypersthene rock. All these
terranes are accepted as types of the Labrador system outside of New
England.

After the discovery of the physical structure of the granites and lab-
radorites of Pemigewasset, it occurred to me that several granitic districts
in Vermont might perhaps be included with it, and they are so delineated
on the map. They are in the northern part of Essex county, about Wil-
loughby lake, Craftsbury, and the high lands east of Montpelier. It may
be that Megantic mountain, Canada, belongs to the same system. There
are good reasons for believing that granitic rocks of perhaps Silurian age
have penetrated the earlier Labrador outflows in Vermont. Besides the
Pemigewasset and Starr King mountain areas, I have marked in the same
way the eruptive rocks of Red hill in Sandwich, Ossipee mountains east
of Winnipiseogee lake, and Gunstock. In Maine, the granite of Biddeford
closely resembles the Conway division of New Hampshire, while that of
Kennebunk is related to it. The Sanford area carries felsite ; while the
York division is like the sienite of Exeter, Dover, N. H., Gloucester, and
Quincy in Massachusetts.

Htironian. The rocks referred to the Huronian cover immense areas.
A very important one, and the most characteristic of all, is that referred
to the Quebec group by Sir W. E. Logan. Beginning at Granville, Mass.,
it passes into Vermont and Canada east of the Green Mountains, con-
necting not far from the province line with the wider belt starting at

12 STRATIGRAPHICAL GEOLOGY,

Ripton, Vt. The two united continue to the end of the peninsula of
Gaspe, passing the city of Quebec, and adjoining the St. Lawrence be-
yond this point. An interesting spur from this area extends from Mem-
phremagog lake to Weedon, P. Q. The next area is the one occurring
along Connecticut river, commencing at Rockingham, Vt., expanding to
the Ammonoosuc gold field, winding along the Upper Ammonoosuc in
Stark, Milan, Dummer, Whiteficld, and Dixville, to connect with a broader
expanse in Pittsburg, the corner of Maine, and so on along the Quebec
and Maine boundary to the head waters of the St. John's river, thence
near the Maine line almost to the St. Francis river, separating the most
northern angle of Maine from Quebec and New Brunswick. There is a
small attendant of this terrane near Moosehead lake. Me., while the felsite
of Mt. Kineo is doubtfully referred here, also.

The next area in size extends from the Bay of Chaleur past the Ken-
nebec river in Maine, enveloping the long granite ridge of nearly 300
miles' length, mentioned above. Smaller outcrops exist along Dead river,
north-easterly from the Katahdin granite, at the mouth of the Penobscot
river, three or four in New Brunswick; and the Portland rocks, possibly
including the Merrimack group in Massachusetts, some feldspathic rocks
about Boston, and possibly those associated with serpentine and dolomite
at Newport, R. I., belong here. The small area west of New Haven,
Conn., is evidently a part of the Connecticut River range, the interme-
diate portions being largely covered by the New Red Sandstone.

In Newfoundland the Huronian system occupies chiefly the south-
eastern promontories. The reference of these rocks to the Huronian is
the more satisfactory, since it is at the instance of Alexander Murray,
Provincial geologist, who was one of the first to describe this system in
its typical locality upon Lake Huron. It may be that portions of the
strata thus referred by him, called the "Intermediate series," will prove
to be higher in the scale, more especially since they yield an Arcnicolitcs
and Aspidclla.

Several areas of andalusite and mica schists in New Hampshire are
left unrepresented upon the map, though indicated by lettering. At the
moment of writing, it is not clear to which of the great subdivisions these
rocks should be referred. Mts. Monadnock and Kearsargc are composed
of this formation.

GEOLOGICAL RELATIONS. 1 3

Cambrian and Silurian. It is in the Cambrian and Silurian forma-
tions that the New England rocks show very distinctive peculiarities, and
I have therefore distinguished between them upon the map. In the St.
Lawrence, Champlain, and Hudson valley we have the following series :

In the St. Lawrence valley the bottom member is the Lower Potsdam
group. Skirting the west base of the Hoosac and Green Mountains, this
is a quartzite i lOO feet thick. Near its termination in northern Vermont
there succeeds a mixture of red sandstone and mottled sandy dolomites,
about 300 feet thick. In New York and northern Vermont two areas of
clay slate occur, with a thickness of at least 3000 feet. In Quebec the
older slate, with interstratified thin limestones, belongs to this series, the
quartzite and sandstone not appearing. There are limestones of this age
at Belle Isle, Anse Au Loup, and Bonne bay. This group is character-
ized by the presence of OlcncUus.

The Upper Potsdam is almost uniformly a sandstone, with fossils indi-
cating its existence as an ancient sea-beach. Its surface is covered by
ripple marks and crustacean tracks. The thickness along the Champlain
valley is about 250 feet ; north of the Adirondacks it rises to 300 and
700 feet. About 75 miles below Quebec a large area of related rocks
has been described by Richardson, having a thickness of 2000 feet. At
the remotest localities named above, the thickness of both the Potsdam
periods rises to 11 74 and 2020 feet. At Canada bay the mass is 5600
feet thick, according to Murray.

The calciferous sandrock is about 300 feet thick in the Champlain and
St. Lawrence valleys. It crops out occasionally on either shore, and is
developed in Newfoundland. It is overlaid by over 1000 feet of lime-
stones containing a peculiar set of fossils, referred by Logan and Billings
to the Upper Calciferous, a formation entirely absent on the main land.

Next comes an immense thickness of slaty and calcareous rocks, inter-
calated in the geological column quite recently, and known as the Quebec
group. Much remains to be learned respecting its limits, but it may em-
brace most of the limestones, marbles, and talcoid schists of western
Massachusetts and Vermont, amounting to 4000 feet or more. They
somewhat exceed this thickness adjacent to the province line, in High-
gate, Vt., and Phillipsburgh, P. Q. Logan describes similar rocks near
Quebec, with related fossils. He has associated with them, upon theo-

14 STRATIGRAPHICAL GEOLOGY.

retical grounds, the whole of the Huronian series from southern Massa-
chusetts to Gaspe, dividing it into the Levis, Lauzon, and Sillery forma-
tions. He supposes the latter assemblage has been metamorphosed so as
to lose its original mineralogical character. The two sets of beds may
often be distinguished by the presence or absence of fossils, the Huro-
nian being usually destitute of any decided evidences of life. The Quebec
rocks are associated with the preceding group, also, in northern New-
foundland, attaining a thickness of 6600 feet.

Next in order are the Chazy, La Motte or Black River, and Birdseye
limestones, not usually much over 150 feet thick, and, so far as known,
confined to the Champlain and Upper St. Lawrence valleys.

The Trenton limestone is one of the most characteristic of the Lower
Silurian formations. In Quebec and New York the maximum thickness
is 600 feet. It may be represented by the lower limestones of Anticosti
island ; at least, more than 1 200 feet thickness is referred to the Tren-
ton and Lorraine scries combined.

The Utica slate is rather a local deposit, estimated at 300 feet along
the Champlain and St. Lawrence valleys. It passes into the Lorraine
shales, or Hudson River group, which everywhere accompanies the Utica
formation. Logan says it must be 2000 feet thick in Canada. These
shales in New York are the equivalents of limestones in Ohio, etc., just as
seems to be the case in Quebec and Anticosti.

Two interesting conclusions may be derived from this summary of the
Cambrian and Silurian of the St. Lawrence valley: first, the thickness
uniformly increases in passing north-easterly ; secondly, slaty, sandy,
and siliceous rocks occasionally change into limestones. Both these feat-
ures are explicable upon the theory of the deepening of the ancient ocean
north-easterly, the slates increasing in deeper water, and the sea-beaches
corresponding to calcareous accumulations out at sea.

The Upper Silurian groups are sparingly represented in the St. Law-
rence valley. There is nothing of this age west of Montreal, in the area
of the map. St. Helen's island, in the river opposite Montreal, belongs
to the Lower Helderberg. Farther east are considerable masses of red
shale, occupying at least three outliers, which are referred by Logan to
the Medina period. Near the end of the Gaspe peninsula are 2000 feet
of limestones, apparently a great development of the Lower Helderberg.

PLATE

l6 STRATIGRAPHICAL GEOLOGY,

The upper members of Anticosti island, amounting to more than looo
feet, appear to range through the whole of the Upper Silurian. The
principal development of the Upper Silurian is therefore in the neigh-
borhood of the St. Lawrence gulf, in the same district with deep sea
deposits of the preceding system. They may connect with the north-
eastern extension of the more eastern ranges of the same age.

Let us now note the character of the Cambrian and Silurian formations
of the eastern or Atlantic. We find, first, a series of slates rather older
than the Lower Potsdam, characterized by the presence of Paradoxides.
At Braintree, Mass., are clay slates of this age several hundred feet thick,
associated with great thicknesses of grits and conglomerates, shown upon
Section i of this chapter. Related rocks are abundant along the New
Hampshire and Maine coasts. Near St. John, N. B., they have been
studied carefully, and consist of slates and grits certainly 2000 feet in
thickness, with the fossils Conocoryphe, Agnostus, EUipsoccpJiahis, Micro-
discus, and Paradoxides. In south-east Newfoundland the last of these
genera has also been found; also, 6000 feet of the Lower Potsdam or
Olenellus formation. \\\ Nova Scotia the auriferous rocks are latterly
referred to the Potsdam series, or the Lingula flags of Great Britain.
Their thickness is very great, probably exceeding that of the Potsdam
rocks below Quebec, in the St. Lawrence valley.

The next series that seems to belong to the Lower Silurian is the clay
slate of central Maine. Portions of this near Waterville abound in Ncrcitcs
and related impressions of rather uncertain affinities. Section 3 of this
chapter crosses them, and they must be several thousand feet thick.
There are numerous smaller areas of similar slates, without fossils, in
other parts of the New England area. A measurement of one of them,
in Lyman, gives a thickness, certainly, of 1500 feet.

In the west part of New Brunswick, passing into Maine, is the Masca-
rciic scries of Bailey and Matthew, which evidently belongs to some part
of the Silurian system. A carefully measured section gives nearly 2000
feet, arranged in five divisions. The rocks are feldsi^athic shales, felsites,
flags, sandstones, and conglomerates, much resembling the Huronian.
The fossils are Lingula, Modiolopsis, and Loxoiicvta. Similar rocks make
their appearance in limited patches off the coast of Hancock and Wash-
ington counties, in Maine. A detailed section of them at Machiasport is

GEOLOGICAL RELATIONS.

17

published in the Maine reports. The resemblances to Huronian schists
may show the origin of the materials, and, necessarily, the later age of
the fossiliferoiis beds.

One of the most characteristic formations of the East is the Gaspe
slate group, including the calciferous mica schist of Vermont, and the
Coos group of New Hampshire. Commencing at the Gulf St. Lawrence,
there is a broad band of slates, slaty grits, with calcareous, ferruginous,
and sandy varieties, often carrying Lower Helderberg, and perhaps
Niagara fossils. They are several thousand feet thick. Little is yet
known of them, save their general distribution. They extend south-
westerly through Quebec, New Brunswick, and Maine, entering Vermont
and New Hampshire with a somewhat altered facies. Logan describes
them on all the north-west-south-east streams tributary to the St. Law-
rence. The area of its distribution is mostly in a forest. In northern
Maine I have crossed it along the St. John's river, as high as the mouth of
the Alleguash. The divisional planes are commonly nearly vertical, con-
sisting in so many places of cleavage that one is tempted to believe the
strata lines are mostly obliterated. No formation occupies a larger area
upon our map than this.

In Quebec, as we approach the United States boundary, two types of
rock prevail in the Gaspe series, — one, a well defined clay slate, abundantly
quarried for tiles, traversed by cleavage planes, and a siliceous limestone.
The slates contract near the line. A narrow area passes from Mem-
phremagog lake, through Montpelier, to a point beyond the centre of
Vermont. Another enters New Hampshire in Pittsburg, crops out at
intervals along the Connecticut valley, being quite prominent between
Bellows Falls and Greenfield, Mass. The limestone seems to undergo a
species of metamorphism, as it passes from north to south. For fifty
miles of its course in Quebec it is clearly a limestone. As it passes into
Vermont, micaceous and hornblendic layers show themselves, and in-
crease southerly, so that midway in Vermont the schists and calcareous
layers are equal in amount. It is here, also, that the area contracts very
much. In southern Vermont and in Massachusetts the mica schists pre-
dominate, and the limestones are scarce. The formation terminates near
the north line of Connecticut, but appears in a limited area, west of the
Huronian and clay-slate outcrops, near New Haven, Conn.

VOL. II. 3

1 8 STRATIGRAPHICAL GEOLOGY.

A formation, closely allied to this calcareo-Pxiicaceous Gaspe series, has
been termed the Coos group, in New Hampshire. It consists of mica
schists abounding in staurolite, hornblende rocks, and quartzite. Its area
lies along the east border of Connecticut river, and it may be 5000 or
6000 feet thick. In the subsequent portions of this volume, the relations
of this group will be fully discussed. It may not be confined to the Con-
necticut valley, as there are rocks of similar character in western Maine
and western New Brunswick.

At Port Daniel, on the St. Lawrence gulf, and at Squam lake, in north-
ern Maine, are limestones and shales, abundantly fossiliferous. over 1000
feet thick, referable to the Niagara group, or, possibly, a little higher.

The developments of the Lower Helderberg series in the east are very
great, far exceeding anything of the same age in other parts of the coun-
try. In the Connecticut valley these rocks occur in several places, suffi-
cient to indicate the former submergence of this area beneath the ocean.
These outcrops will be fully treated of in succeeding chapters. I need
now only to say that the Connecticut valley Helderberg series consists of
several thousand feet thickness of quartzites, limestones, slates, conglom-
erates, sandstones, flags, and probably hornblende schists. In northern
Maine the limestones are mostly wanting, the rocks being slaty. There
is some limestone in Eustis plantation, and near Masardis and Ashland.
The slates border and are interstratified with the Gaspe series. Near
Eastport, in Perry, Pembroke, Cutler, Lubec, etc., the sandy slates and
grits of this age are very abundant, and well filled with fossils. They
cross Passamaquoddy bay into New Brunswick, appearing in several local-
ities, particularly in a long, narrow strip crossing the St. John's river
above the city of St. John. Bailey and Matthew's section of this range
gives a thickness of about 5700 feet to the series.

Similar rocks occur in Nova Scotia. A typical locality is at Arisaig,
which has been considerably explored by Dr. J. W, Dawson and Rev. Dr.
Honeyman. These and others represent in Nova Scotia the greater part
of the Upper Silurian of New York and England, possibly as low as the
Medina, certainly the Clinton group.

This review of the Cambrian and Silurian strata of the St. Lawrence
valley and the hilly region to the east, will enable us to compare them
together, i. The former are mainly sea-beaches and oceanic calcareous

GEOLOGICAL RELATIONS. 1 9

deposits ; the latter, thick slaty and sandy sediments, sparingly calcareous,
probably occupying largely the space between the littoral and pelagic
regions of original deposit. Except for the fossils, there is rarely any
lithological similarity between the formations of the two regions. 2.
There is nothing yet known in the more eastern region of the formations
between the Quebec and Medina. 3. The Upper Silurian is scarcely
known in the Upper St. Lawrence valley, while it predominates in the
east. It will be seen very soon that the Devonian and Carboniferous
are entirely confined to the eastern district. 4. Metamorphism has
operated to some extent upon the strata in the east, and not in the
valley.

Devonian. The lowest member of the Devonian or the Oriskany sand-
stone is well developed in Maine, between Parlin pond and Masardis,
crossing the upper end of Moosehead lake. At its southern extremity the
formation rests upon granites, gneisses, and Huronian schists. These
strata consist of slates, slaty grits, and sandstones, having a thickness of
2880 feet along the Canada road, the structure being that of a shallow
synclinal. On Moosehead lake the Cauda-galli grits have a considerable
development. The same formation is found in Nova Scotia, in Annapolis
county, bordering the Bay of Fundy. The iron ore of Nictaux comes
from this group. I understand that there are small areas of this forma-
tion in New Brunswick, which have not yet been described by geologists.

On Lake Memphremagog there are extensive developments of the
Upper Helderberg limestone. The formation can be traced continuously
as far south as Montpelier, Vt., and it occurs at several localities at the
north-east, as at Dudswell, Lake Aylmer, on the Touffe des Pins, a tribu-
tary of Chaudiere, etc. These rocks evidently are not the same with the
Helderberg strata of New Hampshire.

On the Gulf of St. Lawrence is a great development of Devonian sand-
stones, called Gaspe by Sir William Logan. They are 7000 feet thick,
the upper portions having a red color. The whole series presents analo-
gies with the Upper Devonian formations of New York, as both contain
similar plants. The map shows two large areas of the Gaspe sandstones
north of the Bay of Chaleur. In northern Maine there seem to be sev-
eral small areas of the same formation. Near St. John, N. B., the Upper
Devonian sandstones have been studied with considerable care by Bailey,

20 STRATIGR.\PHICAL GEOLOGY.

Matthew, and Hartt. Their most recent conckisions present the follow-
ing arrangement : first, the Bloomsbury conglomerate, 500 feet thick ;
second, the Dadoxylon sandstone, 2800 feet thick; third, the Cordaite
shales and flags, 2400 feet thick; fourth, the Mispec conglomerate, 1800
feet thick — total, 7500 feet. In the western part of New Brunswick, and
at Perry, Me., are limited patches of red sandstones belonging to the
Upper Devonian, and closely related to the Gaspe and St. John series.
Dr. Dawson has described nearly a hundred species of plants from these
Devonian sandstones.

Carboniferous. The Carboniferous rocks are essentially in two basins,
the one in Massachusetts and Rhode Island, the other occupying portions
of New Brunswick, Prince Edwards island, Nova Scotia, Cape Breton,
and Newfoundland, the greater portion of it underlying the Gulf of St,
Lawrence. The coal of the first basin is anthracite, and the second is
bituminous. According to my own explorations,* the Rhode Island sys-
tem consists of

First, coarse conglomerate, with distorted pebbles, . . . 300 feet.

Schists and slates, 473 "

Second, conglomerate, ......... 464 "

Coal measures, 3500 "

Third, conglomerate, 50 "

Total, 4787 feet.

There are eleven beds of anthracite in these measures at the north end
of the island of Aquidneck.

The Carboniferous outcrops along the Bay of Chaleur consist of con-
glomerates and sandstones, called the Bonaventure formation by Logan,
3000 feet thick. The extensive field in New Brunswick consists of com-
paratively thin deposits spread over a large surface, and contains very
little coal. The coal measures and millstone grit combined are 600 feet
thick, according to Bailey and Matthew. In Nova Scotia is exhibited
one of the most remarkable sections in the Carboniferous of any part of
North America. Dr. Dawson arranges the whole Carboniferous series
as follows:

(i) The lower coal measures.

* Proc. Avier. Ass. Adv. Sci., vol. 14, p. 112.

GEOLOGICAL RELATIONS. 21

(2) The Carboniferous limestone.

(3) The millstone grit series, 5000 to 6000 feet thick.

(4) The middle coal formation, 4000 feet thick.

(5) The upper coal formation, 3000 feet thick.

Logan's section at the Joggins gives 14,700 feet thickness to the whole
Carboniferous series. At Pictou it has also a thickness of 16,000 feet.
J. P. Lesley thinks these thicknesses must be exaggerated.

Triassic. Three well-marked areas of the Triassic formation appear
on the map. The one best known occupies the Connecticut valley in
Massachusetts and Connecticut, the area being about 2200 square miles.
The formation is at least 5000 feet thick, divided into three sections.
The lower part consists of coarse red sandstone ; the middle, of fine sand-
stones, shales, flags, etc. ; the upper, of reddish sandstones and conglom-
erates. Over most of this area a mass of dolerite divides the middle
from the lower section. The two upper divisions contain the footmarks
of birds, which have given the Connecticut River sandstones their well-
known celebrity.

The second Triassic area occupies the shores of the Bay of Fundy. A
very large amount of trap containing native copper occurs in connection
with it. The third area occupies nearly the whole of Prince Edwards
island.

Cretaceous. This formation appears at the southern extremity of the
map, on the northern shore of Long island. It is a continuation of the
plastic clay of New Jersey. It is a fresh-water deposit, containing lignite
and a few shells. Its character suggests the existence in the early Cre-
taceous period of a long, narrow, fresh-water lake, necessitating the pres-
ence of very different physical conditions from those now existing in that
vicinity.

Cenozoic. The tertiary and alluvial deposits represented on the map
occupy a place outside the Cretaceous, between New York and Cape Cod.
Their absence north-east of Massachusetts has suggested the theory of
the submergence of the middle and northern sections of the Atlantic
district in very recent times. Possibly Sable island, off Nova Scotia, and
the great banks of Newfoundland, may indicate the position of the place
of these Cenozoic deposits, and consequently the outer limit of this por-
tion of the continent at the close of the Tertiary period.

STRATIGRAPHICAL GEOLOGY.

Sections.

I present herewith three sections passing across the most important
parts of the field of the map. Taken in connection with the map, they
will afford a correct notion of the geology of this district.

Geological Section from PlynioiitJi^ jMass., to WJiitcJiaU., N. 1'.

This section is i8o miles long, and exhibits the older rocks of eastern Massachusetts,
the Atlantic group in New Hampshire and Vermont, the so-called Taconic rocks in
western Vermont and eastern New York, the Adirondack or Laurentian series, and
several less important groups.

Underneath the drift of Plymouth and Kingston there lies a broad band of granite,
the north-eastern extremity of the range continuous from Little Compton, R. I. The
descriptions given of it are not sufficient to enable me to compare it directly with any
of the New Hampshire groups, though there are suggestions in favor of a reference of
certain portions to the Bethlehem and Labrador groups. Nor is it known how this
band stands related to the sienite, which appears next in Pembroke. The Carbon-
iferous system which succeeds is the northern extremity of the New England anthracite
coal-field. The strata are largely slates and sandstones, with a moderate northerly dip,
and rest upon a floor of sienite. No beds of anthracite are known in this neighbor-
hood ; and the few exposures may belong to the lower part of the group. It is the
newest formation exhibited upon the section.

The sienite is the fundamental rock of south-eastern Massachusetts. It comes to
the surface four times in our route of travel. Being an eruptive rock, it is evidently
newer than some of the neighboring gneisses, either the New Bedford range (which
may possibly touch the end of our section) or that which appears between Sudbury and
Harvard. Not all this rock, however, is to be regarded as eruptive. It merges into the
hornblendic gneiss of Wayland and Sudbury, and is often traversed by divisional
planes very suggestive of strata. The group also contains beds of limestone and ser-
pentine, and there are conglomerate portions. As the limestones of this series and the
gneiss of Bolton carry the organism Eozoon, the whole series is evidently allied to the
Laurentian. The geographical situation of the sienite and eozoonal gneisses naturally
suggests a Laurentian age, for they may belong to the Acadian ranges of these older
rocks, and they certainly lie to the cast of all the debatable metamorphic formations.
The similarity of the sienites to rocks among the White Mountains, described else-
where as cutting the Labrador sediments, as if at the termination of their period of
formation, affords reasons for supposing them to be of the same age. Thus we are con-
fronted with two theories of the age of the sienite. Were it possible to decide the
question of age without further field-work, it might be said that the apparently stratified
IDortions may be of Laurentian age, while the other masses may have been erupted in
the Labrador period coeval with Red hill and Tripyramid. The probability of the

GEOLOGICAL RELATIONS. 23

greater antiquity of the gneiss has led to the representation of a folded anticlinal be-
tween the two hornblcndic bands in Sudbury.

The concentric structure of the Boston basin is very obvious, and is shown partly in
the section. There is first a grand sweep of gneisses from Andover and Billerica, in a
south-westerly and then southerly if not south-easterly direction into Rhode Island.
They then pass under the coal-field and the waters of Narraganset and Buzzard's bays,
to come up in the New Bedford range. This V-shaped area encircles in similar form a
broad but narrower band of hornblendic gneiss and sienite. Within the sienites is a
band of compact feldspars and porphyries. A little north-west of Hydepark one mem-
ber of this series is a very coarse conglomerate. The section crosses the southern part
of this range obliquely, and thus magnifies its thickness. It does not crop out notably
next the sienite in Waltham or Watertown, but may be seen in the same geological
situation between Melrose and Swampscot. It has been suggested that these felsite
beds are of Huronian age. Similar rocks occur abundantly in the New Brunswick
areas of this age, though very rarely about the Lake Huron or Vermont terranes.
Within the red felsites is a series of Cambrian rocks, showing the characteristic Para-
doxides in slates near the base. Below are conglomerates of limited extent; but above
is the well known Roxbury conglomerate, used extensively for building purposes in
Boston. To the north of this is another set of slates. Prof. N. S. Shaler estimates
the thickness of the lower conglomerates or sandstones at several hundred feet. The
Braintree slates, together with the lower beds, may be not far from one thousand feet
thick. The Roxbury conglomerate is estimated from twelve hundred to two thousand
feet and more. The upper slates, — called "Cambridge slates," — are thought to be three
hundred feet thick.* All these Cambrian rocks dip northerly, from fifteen to twenty
degrees.

From all that I can learn respecting the structure of this Boston basin, from the
writings of J. F. andS. L. Dana, my father's reports, Prof. Shaler's papers, and orig-
inal observations of a limited character, in this and the analogous basin of Parker
river, f I conclude that the monoclinal dip of the Cambrian rocks about Boston is not
altogether the primal condition, but the result of an overturn. If this be a correct
induction, the Roxbury conglomerate will be found to be at the summit of the series.

The next conspicuous set of rocks on the section is the Merrimack series, occupying
the valley of Nashua river. The lower portion consists of mica schists of various text-
ures and micaceous quartzites, with occasional beds of indigenous granites. In Groton
and in Rockingham county, N. H., a bed of soapstone is present. In Harvard the
granite is unusually abundant, connected with an interesting conglomerate considerably
altered by metamorphism. The resemblance of these beds to what I have thought to
be Huronian rocks, near Portland, Me., makes the suggestion worthy of consideration
whether the Merrimack group of my annual reports should not be regarded as nearly
the equivalent of the Huronian. Hydro-mica schists are rarely met with in the Merri-
mack valley,' but the synclinal basin of schists is overlaid by clay slates not unlike

* Proc. Boston Soc. Nat. Hist., vol. xiii, p. 172. t Proc. Ainer. Ass. Adv. Sci'., i860, p. 118.

24 STRATIGRAPHICAL GEOLOGY.

strata of the same name in New Hampshire, Vermont, and Canada, overlying the
Huronian. The latter may merge into the andalusite variety cropping out on Mts.
Monadnock, Kearsarge, the east side of Washington, etc.

In the south part of Lunenburg the section crosses an interesting band of white
quartzite over fifty feet wide. This band I have traced directly to Nottingham, N. H.,
the rocks becoming more micaceous and schistose north of the state line. Lithologi-
cally, it closely resembles two bands of the same rock crossed farther north by our line.
The outcrop is on the track of the Fitchburg Railroad.

The section next crosses a broad belt of gneiss supposed to belong to the Atlantic
system, and to consist mostly of the Lake division. Four well marked anticlinals have
a place in it before coming to Monadnock. The first is the Wachusett anticlinal, fig-
ured by my father in his final report, and not observed on the line of section, perhaps
for lack of outcrops. As it occurs on both sides, it must be continuous across the sec-
tion, while there is evidence to suggest the erosion of its eastern portion. Mt. Wachu-
sett lies on the eastern flank of this axis. The next anticlinal makes the dividing ridge
between the Merrimack and Connecticut waters in Ashby, Mass., and New Ipswich,
N. H. The fourth axis brings up the underlying porphyritic gneiss. Between the
main water-shed and Monadnock is the stratigraphical place for two remarkable bands
of white quartz. These have been described and mapped in the annual report for 1873.
As their outcrops have been traced almost continuously from Temple and Mason to
AUenstown, if not Strafford, no doubt can remain as to their persistency. A protracted
search has so far been unavailing to bring them to light in New Ipswich, most of
Mason, Rindge, or Sharon, but two similar bands appear in Royalston, Mass., along
the same north-east-south-west line ; — so that the theory is admissible that the nearly
horizontal mica schists of New Ipswich, Ashby, and Temple may conceal the under-
lying quartzes for a considerable distance. The same bands come up again between
Keene and Connecticut river.

Mt. Monadnock seems to be an isolated contorted synclinal of andalusite mica
schist, resting upon the upturned edges of the gneisses. The vicinity of the mountain
is a plateau (Vol. I, p. 209), so that these schists suggest an incredible amount of ero-
sion. The little map in this chapter shows the extension northwardly of a series of
these outliers.

The Montalban division makes its appearance between Monadnock and Keene.* At
Troy village the dips are easterly, so that the older rocks beneath Monadnock are ar-
ranged in synclinal form, showing that the andalusite schists were deposited along an
original depression. The "Concord granite" of Marlborough succeeds, with essentially
the same position.

Near Factory Village, in the north-cast part of Swanzey, the Lake division of the
Atlantic group makes its appearance, and continues to the newer rocks of the Connect-
icut valley. In the south part of Keene the dips conform to the overlying Montalban

* The facts stated concerning the strata between Monadnock and Connecticut river are furnished by J. H.
Huntington, from recent field-work.

GEOLOGICAL RELATIONS. 25

of Marlborough. On ascending the ridge west from Keene, we find the Cheshire Rail-
road has cut through the ledges very extensively, thus affording excellent means for
determining the position. In the first considerable excavation the strata are extremely
variable in jjosition and character. First, there is a reddish gneiss. Next, a quartz
band breaking into jointed rectangular fragments. Thirdly, there is a chloritic rock,
standing nearly vertical. In the "mile cut," in the south corner of Surry, the first
rock is hornblende schist, dipping N. 60° W. The second is chlorite schist; then
twenty or thirty feet thickness of quartz. Gneiss succeeds, with numerous irregulari-
ties, but with the more common dip of 20° N. 60° W. The Cous rocks are mainly
quartzites, with a high north-westerly dip, and they are unusually well developed in
Westmoreland.

The facts concerning the section between Connecticut river and New York are
derived from the Vermont report, mainly from Sections IV and V. In Putney, late
observations indicate the presence in the clay slate of an anticlinal axis, showing that
this formation is probably older than the adjoining schists. Upon this theory, the east-
erly dip of the western border of the slate must be an overturn. The two axes in the
Calciferous mica schist are given from the appearance in Sections I, II, and III, and
the Black Mountain granite is represented in the ridge of the anticlinal. Next succeeds
the Atlantic gneiss, — perhaps Montalban, with several folds. Three important anti-
clinals appear. The first occurs on each of the six lower sections of the Vermont
report. Between the first two anticlinals is a band of Huronian, perhaps a synclinal,
as there are magnesian bands near both the borders. It is the main hydro-mica schist
range of Vermont lying east of the Green Mountains. In Londonderry the gneiss is
more largely feldspathic than usual, and presents some points of resemblance to the
Lake gneiss or the Laurentian. The axis along the main range of the Green Moun-
tains in Peru and Dorset is very clearly indicated in the outcrops, thus corresponding
with its usual structure, displayed most satisfactorily, however, where the range has
been cut down by the passage of the Winooski and Lamoille rivers. This axis is
often an overturn, the strata being apparently monoclinal.

After passing the Green Mountain axis, we are brought into contact with what have
been known as the " Taconic rocks," and into a region of gigantic upthrows and down-
throws, which have occasioned much difficulty in the unravelling of the structure. I
may not satisfy all with the interpretation given to the structure of these rocks, but
present that view which seems most correct. The quartzites of East Dorset and West
Peru dip westerly when in contact with the gneiss. The western border has an east-
erly dip, so that the structure is synclinal. The eastern part is much more elevated
than the western, so that our band itself is inclined, much like the new moon in the
position supposed by many to indicate a wet month. The same view of the position of
the quartz and its relations to the gneiss is given in Dr. Asa Fitch's section, in his
paper in Trans. N. Y. State Agr. Soc, 184-D. His section crosses the same formations
in Winhall, the next town to the south of our section. By way of further confirma-
tion, it may be said that Emmons figures a similar state of things about twenty miles
VOL. II. 4

26 STRATIGRAPHICAL GEOLOGY.

to the south in Sunderland, agreeing with the representation on Section III of Vermont.
The relative positions of the formations are the same all along this line. This quartz-
ite carries the ScoUtJucs linearis, and on that account was believed by Prof. James Hall
to be of Potsdam age. Billings regards it as the lower Potsdam, as the ScolitJms is a
different species from the one common in this sandstone in Canada. Logan represents
this rock as of the same age upon his maps of iS6S and 1869, but I understand he more
recently expresses the opinion that it belongs to the upper part of the Quebec group.
Others sympathize with this view. Granting the correctness of our section, in accord-
ance with the early views of Hall, it would indicate the presence of two shore lines in
the Cambrian period, in this part of the country. The one beach reposed upon the
west flank of the Green Mountains. The other, possibly connected by deep sea sedi-
ments of the same age with the first, was deposited at the eastern base of the Adi-
rondacks, especially in the neighborhood of Lake Champlain.

The next formation is the Eolian limestone, probably of the Quebec group. In the
North Dorset valley a segment of it has been thrown upon end, but the normal position
appears in Eolus and Danby mountains, where about two thousand feet of limestone
repose horizontally, overlaid by talcoid schists. The basal layers approximate to quartz-
ite, some observers insisting that they have identified the latter rock among them,
which is made to appear beneath the surface in our representations. The upper part
of the limestone consists of the two thick layers of white marble, for which Vermont
is celebrated. Farther north, later studies indicate that the marble caps the limestone
series. Billings describes unmistakable Chazy fossils from near this marble layer in
West Rutland. The continuation of the beds to the extreme north also connects them
with layers abundantly charged with characteristic fossils of the lower Quebec group.
The rock is the same also with the Auroral limestones of Pennsylvania.

The top of Danby mountain, shown a little farther to the south, consists of the same
schists, apparently, with those of Haystack mountain. These latter beds have an ap-
parent dip beneath the limestones. It is therefore necessary to believe in the existence
of a fault in the valley between the two mountains. This is the more easy, since the
Danby Mountain limestones and marbles do not continue uninterruptedly to Rutland.
The enormous lateral pressure caught the thick Taconic sediments in a most powerful
vise, as it were, between the Adirondacks and Green Mountains. Hence the interven-
ing valley is filled with faults and upheavals, usually very marked in the limestones,
because they are not so strong as the schists, and give way more easily. The Eolus
and Danby Mountain mass, like the precisely similar synclinal piles of Equinox,
Anthony, and Greylock mountains, happened to be forced upwards in the shape of
an immense cuneiform segment. The Danby marble layer is more than twelve hundred
feet higher than the same bed in Wallingford, four or five miles distant.

The limestone often crops out to the west of the Haystack range, though never so
extensively as on tlie east. It is most extensively developed in this position at the
northern extremity of the schists near Sudbury. The stone is filled with veins of cal-
cite, so as to make the name of "sparry" appropriate. The limestone of this kind on

GEOLOGICAL RELATIONS. 2/

Haystack does not belong to this band, but there is reason to believe it lies beneath
the mountain. This thicker range of schist also carries large beds of conglomerate.

The schists are succeeded by a thick deposit of beautiful clay slates, from which are
taken annually thousands of bright colored roofing shingles. It is the Georgia slate of
the Vermont report, supposed to belong to the lower Postdam group. The dip is east-
erly, but the irregularities are great enough in Wells to allow the existence of an
inverted anticlinal axis. A somewhat similar band occurs in the eastern part of White-
hall. It is not clear whether these two bands are united by a synclinal beneath the
schists next west, or whether the eastern belt has been elevated in connection with a
fault.

The anticlinal in the schists west of the R. & W. R. R. is copied from Mather's re-
port, p. 424, pi. 28, fig. I. Mather did not accept our representation of the slates to
the west of this hill, believing there were successive uplifts of Calciferous sandrock, un-
derlaid by the Potsdam sandstone. This anticlinal explains why there should be a
broad expanse of the thin Calciferous sandrock, Chazy and Trenton limestones in West
Haven, Vt., north of the Poultney river; for all the northern prolongation of New
York is entirely occupied by Taconic rocks, which disappear wholly north of the bend
of Poultney river. Probably further search will develop the continuation of the Chazy
east of this anticlinal, between West Haven, Vt., and Hartford, N. Y. The elevation
has been considerable, but patches of this limestone may have escaped denudation in
some sheltered spot. The lower slates carry Olenellus and other characteristic lower
Potsdam fossils a few miles to the south. These slates agree in age with those holding
the Paradoxides in Braintree. The evidence seems to confirm the observations of
Emmons,* near Whitehall, to the effect that the Calciferous sandrock rests upon the
slates east of the village, the white sandstone having thinned out eastwardly. But it
extends a great distance southerly, and there are also a few outliers of this sandstone
in the same direction, indicating the greater lateral spread of the original beach mate-
rials in that direction. The Potsdam rests unconformably upon a very silicious rock
west of Whitehall, but more especially in West Haven. f This may correspond with
the quartzites in Dorset, as well as to the lower Potsdam sandstone of the North-
western states.

*■ Agrictilttire of N. V., vol. i, pi. 18.

t Most observers have passed by this quartzite, as if it were undoubtedly Laurentian. The section showing it
is in the Vermont report, vol. i, p. 263. I observed it in 1857, and well remember my speculations respecting it;
but, as it was my first view of the world-renowned Potsdam, I could not expect my youthful observations
entitled to credence, were any startling generalizations proposed. I said in my note-book, — "Here is a case of
unconformability in the Potsdam sandstone; the formation is not a simple one, as is universally described, but
represents ages so diverse as to be separated by an unconformability of 25 degrees." In my published descrip-
tion, I have not ventured to suggest so much, expressing the opinion that "the rock with the greater dip is as
distinctly quartz as the other; and there is also a large ledge of quartz rock upon the west side of Lake Cham-
plain, with the same inclination. Hence the sudden change in the dip is to be regarded as a safer distinction
between the Silurian and Laurentian series, than a difference of lithological character."

Since 1857, the recognition of the western Vermont quartzite as lower Potsdam, by Billings, and the formal
separation of the St. Croix and Potsdam in the north-west, bring to mind my early speculations, and excite the
anticipation that further researches will develop the older group, with its fossils, along the outer line of the Lau-
rentian in the Adirondacks.

28 STRATIGRAPHICAL GEOLOGY.

Plate II, illustrating the position of the formations described above as constituting
Section I, will be found represented upon page 15 of this volume.

Section II. From Portland, Me., throiigh Mt. WasJiington, to Aber-
cro7nby, P. ^.

This section is 205 miles long. It passes through the highest pinnacle of the White
Mountains, intersects the Green Mountain anticlinal axis in Canada, traverses the long
plain of Utica slate, near Montreal, and terminates in the Labrador system.

The first exposures in the islands of Casco bay, off Portland, are of mica schists,
quartzites, soapstone, pyritiferous, plumbaginous, and hornblende schists, referred by
us to the Huronian.* The prevailing dip is north-westerly ; but a careful examination
of the dips, in the neighborhood where the bay does not conceal the outcrops, indicates
the existence of at least six folds in this basin. The main synclinal line is situated a
short distance to the north-west of Portland. The formation is essentially the same
with that traversed by Section I, in the Merrimack or Nashua River valley, save that its
lithological characters are more suggestive of Huronian affiliations.

The relations of this to the adjacent gneiss of Atlantic age are plain, while the dips
of the newer group are the steepest. In Deering, where the formations join, they pos-
sess the same inclination of sixty degrees south-easterly. The rock of Phippsburg is
gneiss, and is probably continued beneath the ocean to connect with the exposures at
the Isles of Shoals. Hence there may be an outer vein of gneiss, embracing the Huro-
nian schists as closely as the corresponding formation on the north-west side, as exhib-
ited in the section. Perhaps the fact of a usually low dip to the gneiss is not well
shown. Two suggestions may explain it : first, the rock may have been formed, meta-
morphosed, and elevated before the deposition of the Huronian system, and, at the
later period of elevation, the slates being more easily moulded, were forced into the
steeper inclination ; or, secondly, a portion of the less inclined strata may belong to
our later division, called, for convenience, the Rockingham mica schist, which may
easily be confounded with the Montalban series.

Our information respecting the dips of the rocks to the north-west of Portland, in
Maine, is very meagre. The whole distance has been hastily traversed. A synclinal
axis is revealed just before reaching Sebago lake ; after which only a south-easterly dip
appeared as far as the state line. The ledges are greatly concealed by drift all the way.
When more carefully studied, inverted dips will probably be found in many places.
There would seem to be one important anticlinal between the Maine and White Moun-
tain divisions of the Montalban area.

One of the striking peculiarities of New Hampshire geology next makes its appear-
ance, as revealed upon Mt. Pequawket. Three kinds of granite, with limited masses
of slate, compose the mountain. The lowest or Conway granite apparently lies hori-
zontally upon the upturned edges of the Montalban schists. This outcrop is the edge

* Proc. Amcr. Ass. Adv. Sci.,\Zj;i, p. 163.

GEOLOGICAL RELATIONS. 29

of an extensive field, not less than four hundred square miles in extent. The Albany
granite, or the second horizontal layer, is thinner than the first in this locality, but is
as thick in other parts of the basin. Both the granites are thinner at this outer edge
of its area, and thicker in a westerly direction, the first to the greatest amount in Bart-
lett, along the section line. Above the Albany granite are found two masses of clay
slate, somewhat indurated and much contorted, the one on the south and the other on
the north side of Pequawket. These are of too limited extent to find place on our
section, but are important in the history of the mountain. The formation is identical
with the andalusite slate on the east side of Mt. Washington, represented in the Plate.
It is to be presumed that the outcrops were formerly directly connected, though their
nearest exposures are certainly ten miles removed, the disappearance being probably
due to denudation. This slate is apparently much more modern than the Conway and
Albany granites, possibly of Paleozoic age.

The igneous material of the upper and principal portion of Mt. Pequawket is more
recent in origin than this slate, since fragments of the slate are disseminated through
it. The lower portion is mostly a breccia, made up of the slate fragments, which grad-
ually diminish in quantity in ascending the mountain. The igneous paste is feldspathic,
and approaches the Albany granite in lithological structure. The same granitic rock
composes the main bulk of the Mote mountains, on the opposite side of the Saco river.
Very likely the two mountain masses were connected at the time of the eruption of the
unstratified material, and the broad valley between has since been excavated by atmos-
pheric agencies. No other localities of this Pequawket granite have been discovered,
save a few feet thickness of breccia on Mts. Willard and Tom, near the Crawford
house.

The Montalban schists, from Jackson to the west base of Mt. Washington, have a
north-westerly dip, with innumerable local contortions. I advocated the doctrine that
Mt. Washington is an inverted anticlinal, in the annual report of progress for 1870. A
collation of all the dip observations upon the mountain indicates the presence of a few
easterly inclinations upon the eastern side, where erosion had spared the upper layers.
A common phenomenon is the occurrence of a low, undulating, south-easterly dip, ob-
servable for several rods, which changes suddenly into a nearly vertical north-westerly
pitch, folding underneath the first. When we descend into the deeply excavated
ravines of Tuckerman and Peabody river, west branch, the latter inclination is the com-
mon one, since the surface undulations have been washed away, and only the folded
strata remain. This phenomenon occurs mainly in the andalusite slates, as seen along
the carriage-road. Full details concerning the variations will be found in the descrip-
tion of Section IX. Furthermore, the general position of these evidently newer slates
is monoclinal, with no corresponding repetition, on the eastern side of the valley, of
similar strata exhibiting a dip in the opposite direction, as would be expected should
the theory of a folded axis be set aside.

At the west base of Mt. Washington is a large amount of granite, carrying long,
slender crystals of orthoclase, which give somewhat of a porphyritic aspect to the rock.

PLATE III.

GEOLOGICAL RELATIONS, 3 I

It is evidently a part of the Montalban series, as may be possibly the coarser but still
rather fine-grained granite of Mt. Deception. The succeeding formation in Jefferson
is more nearly allied to the Lake than the Montalban division of the Atlantic system,
though not so labelled upon Plate III. On Jefferson hill and at the mills the rock is a
common gneiss, with a plenty of feldspar, and usually but slightly inclined to the hori-
zon at the surface exposures. The deeper portions are represented as very highly
inclined, in order to make the dips conform to the supposed position of the Huronian
rocks which succeed.

Our information respecting this Huronian band in Lancaster and Guildhall is meagre.
The first met with is mostly a quartzite, with slight signs of stratification. The portion
in Vermont can be readily referred to both the Lyman and Lisbon divisions of the for-
mation, and there are certainly two folds. In this area the usual copper belt of these
green hydro-mica rocks has been discovered. This group is followed by a synclinal of
Coos staurolite schists in Granby, which is supposed to be the continuation of the Con-
necticut River range of this formation, though on the west flank of the underlying Hu-
ronian. It is connected with the main Coos group in the north part of the Cocis and
Essex district, which is entirely on the same side of the lower group. In the west part
of Granby the Montalban series reappear, with an easterly dip. This is supposed to
be the repetition of the White Mountain rocks beneath the Huronian and Cocis series,
and it may underlie the granites of East Haven and Willoughby mountain.

The space betv/een the two granite masses just referred to is occupied by the Calcif-
erous mica schist, v.'ith a monoclinal easterly dip, most likely a synclinal fold. A well-
defined synclinal structure can be made out in the same rock in Brownington and
Barton, which corresponds to the behavior of the same formation for the first thirty
miles of its occurrence in Quebec. (See Plate VI.) The clay slate and Helderberg
limestone farther west hold the same position with the corresponding groups on Lake
Memphremagog, at Owl's Head. Logan thinks they occupy a long, narrow, inverted
synclinal trough at OwPs Plead, which is apparently the correct theory of their position.

We come next to the beginning of the great development of Huronian, or the meta-
morphic Quebec group, as designated by Logan. There seem to be first an anticlinal
and then a synclinal axis, before reaching the Green Mountain older ridge. Beds of
serpentine and steatite appear in Troy, and they dip towards each other, according to
the Vermont report. The anticlinal altitude of the Green Mountain range is agreed
upon by all observers, though Logan thinks it subordinate to a basin, and that the
whole mass of the mountain is newer than the serpentines. Inasmuch as ten out of
fourteen sections across this range, according to the Vermont report, have the ridge
structure, while the others may be interpreted easily as folded axes, it seems more likely
that the Green Mountain gneiss is of the same age with the Montalban series, which it
resembles, and that both underlie the adjacent serpentinous rocks, or the Huronian.

The remainder of the section is copied from Logan's representations in the Canada
reports. After the first basin there succeed the Stanbridge anticlinal and the Farnham
synclinal, before we come to the great fault between the older metamorphic schists and

32 STRATIGRAPHICAL GEOLOGY.

the unaltered Trenton, Utica, and Lorraine * formations of the St. Lawrence valley.
There are numerous minute corrugations in the Huronian strata, to the north-west of
the gneissic axis. After i^assing the Huronian, the type of formation is that of the St.
Lawrence valley, in distinction from that of the more elevated Atlantic region.

Upon St. Helen's island, in the St. Lawrence, opposite Montreal, is a deposit of
Upper Helderberg rocks. The Trenton has been cut on Mt. Royal by a powerful dike
of dolerite, which rises back of the city of Montreal in a picturesque manner. To the
north-west of this hill appear in order the Trenton, La Motte, and Chazy limestones,
the Calciferous sandrock, and the Potsdam sandstone, all lying nearly horizontally, with
slight synclinal and anticlinal curves. The last rock on the section is the Labrador
system, cropping out in the best known region of its distribution. It probably ex-
tends a considerable distance beneath the fossiliferous limestones, and has been much
crumpled by lateral forces, being occasionlly inverted.

Section III. From Mt. Desert Island^ j\/e., to Boiirg Louis., P. J^.

This section is 220 miles long, and is represented upon Plate IV. The first i^art is
mostly derived from a section from Mt. Desert island to the Canada line, published
by myself in the second annual report upon the geology of Maine, in 1862. The other
portion is compiled as well as may be from the Canada reports.

The first rock is a sandstone, at Bar harbor, dipping at an angle of twelve degrees.
Ripple marks cover the surface of many layers, and curious cylindrical stems tantalize
us by their resemblance to fossils. The formation is probably of Cambrian age. The
principal part of the island is composed of protogene, with seams resembling strata.
Upon the summit of Green mountain these planes dip 60° N. W. At Eagle pond they
stand vertically. The first unmistakable strata appear at the north end of the island,
consisting of common and talcose gneisses, dipping from 30° to 45° south-easterly and
towards Green mountain. The rocks bear a little resemblance to the Bethlehem group
of New Hampshire. The water of Frenchman's bay, and a considerable sand in the
south jjart of Trenton, obscure the junction between the gneiss and micaceous schists of
Huronian aspect. The dijDS are at first north-westerly, and south-easterly after passing
Ellsworth village. A calculation of the thickness of the strata, upon both sides of the
basin, shows them to be 13,000 feet in amount.

Next there succeeds eleven miles' breadth of porphyritic granite. My impression is
that the crystals in this granite are larger than is common in New Hampshire, and that
their larger axes are not arranged in parallel lines. This band is part of the immensely

* The names of Lorraine and La Motte on the section are used instead of Hudson river and Black river,
because the latter do not stand the needful tests of appropriate definition, or of early suggestion. The true
Hudson River rocks are now shown to be much older than the place of these shales, as advocated by Prof.
Emmons many years since. It is proper, then, as the view so long upheld by Emmons, in opposition to most
geologists, has finally been vindicated, that his name of Lorraine should be used when speaking of the slates
above the Utica. La Motte limestone or marble was proposed by C. B. Adams, prior to the use of Black river,
in the New York reports. The marble is also much thicker in Isle La Motte in Vermont, than along Black
river in New York.

GEOLOGICAL RELATIONS. 33

long stretch of granite extending from the Bay of Chaleur to St. George, Me., if not
beneath the ocean to New Bedford, Mass.

West of the granite there is a considerable quartzite, dipping south-easterly, and
then in the opposite direction, forming an anticlinal. Following it is an immense
Stretch of micaceous schists, showing at least two well marked axes, the first in Ken-
duskeag, the second in Charlestown. I have been informed that there are smaller
subordinate folds along this line not here represented.

A broad band of clay slate succeeds the schists, and shows three axes, the first and
most marked being at the crossing of Piscataquis river. The rock is uniformly a clean,
soft clay slate, with very few dissimilar strata. A multitude of slate quarries are lo-
cated upon this band, furnishing the best quality of roofing shingles obtained in any
part of the country. There is a narrow band of a pretty conglomerate marking the
eastern edge of this formation. The last axis in the slate is on the south-west side of
Moosehead lake, near Greenville. Following the lake border, we find a considerable
mass of sienite. Squam mountain is mainly composed of slates, with corals on its
southern slope, as reported by J. T. Hodge. As far as to the hill opposite Mt. Kineo,
the rocks appear to be slaty, and the whole series is probably Silurian, and of more
modern date than the clay slates recently passed over. But scarcely anything is known
of them. Mt. Kineo is composed of a compact felsite or siliceous slate, whose struc-
ture it is not easy to determine. Viewed from the east it presents some resemblance
to a crushed anticlinal, and, as this structure is in accordance with the best suggestions
possible as to its age, we may accept it for the present as correct. The formation may
be Huronian, lying beneath the fossiliferous members on both sides of it.

The rocks on Moosehead lake, beyond the felsite, are better understood, as they
contain, first, the peculiar fucoid of the Cauda-galli grit, and then marine forms charac-
teristic of the Oriskany sandstone. Our observations would give an anticlinal struc-
ture to this formation, which differs from that ascertained to characterize the same
band at Parlin pond. The occurrence of this well-established fossiliferous horizon in
the midst of the crystalline schists is of great importance, since it enables us to say
decidedly that the two classes of rocks are not interstratified with each other, and that
therefore the latter are older than Paleozoic* Beyond the lake, on the west branch of
the Penobscot, the rock verges into a slate, whose cleavage planes may obscure the
stratification. While these dip at an angle of 6o°-7o° north-westerly, it is very likely
the strata dip only io° or 12° in the same direction. It is not impossible that these
slates represent a different formation, the same which occurs farther on. First, how-
ever, our line passes over a few miles' width of the Huronian mica schists, with three
or more axes. The slates display, as a whole, the synclinal form, with a small anti-
clinal in the centre, at Lead-better falls. Other minor or local foldings were observed
in them. The formation may correspond with the Upper Silurian slates or Gaspe series
of Ouebec, as well as with the same range at the Moose River settlement on the Canada

See paper on geology of the north-west part of Maine. Proc. Amcr. Ass. Adv. Set., 1873, p. 163.
VOL. II. 5

PLATE IV.

"""b,

Us

V

*v.

V

%^

^5.-,

GEOLOGICAL RELATIONS. 35

road. In Township No. 4, R. 18, the hydro-mica schists reappear, and form a high
ridge, through which the west branch has excavated a deep gorge. The same roclc is
supposed to continue across the highland boundary between Maine and Quebec into
the valley of the Du Loup river, one of the tributaries of the Chaudiere.

The first formation in Canada consists of fine and coarse micaceous clay slates, with
gray micaceo-argillaceous sandstones, weathering greenish in the air, and turning red-
dish when exposed to running water. They are supposed to be Huronian. Next
succeed the Gaspe slates. The rocks resemble those just described, consisting chiefly
of gray sandstones, approaching a coarse mica slate. These sandstones are interstrati-
fied with calcareous beds, too siliceous to be used for the manufacture of lime, and
crop out along the lower three miles of the course of the Rivifere du Loup. They com-
monly dip 62° S. -^7° E. These beds resemble the Calciferous mica schist of Vermont.

The section next crosses a band of fossiliferous Helderberg, having the same position
as the preceding formation. The best localities are on the Touffe des Pins and Famine
rivers. This would naturally occupy the place of a synclinal in the Gaspe series ; and
consequently the rocks which follow, extending as far as the parish of St. Francis, a
few miles above the Guillaume river, are repetitions of those adjacent to the Helder-
berg on the south-east. As they all dip south-easterly, those nearest Maine must have
been inverted.

The section now runs parallel to the Chaudiere river, and, after reaching St. Etienne,
follows Section No. 9 of the maps and sections published by Sir William E. Logan to
illustrate the report of progress of the geological survey of Canada, from its commence-
ment to 1863. The formation succeeding the Gaspe slates is referred in the Canadian
report to the Quebec group of the Lower Silurian, but it is the same with what is called
Huronian elsewhere upon this section. The first outcrop is the north-easterly continua-
tion of the ridge from Memphremagog lake towards Sherbrooke. This is followed by
the Sutton and St. Joseph anticlinal. The width of the Shipton and Leeds synclinal
is about fifteen miles. Magnesian limestones, quite crystalline, occur on both sides of
the basin, interstratified with chloritic slates, specular, and hydro-mica schists, epidotic
rocks, and red slates. Extensive beds of copper sulphuret are connected with these
schists. The upper part of the basin is referred to the Sillery sandstone. The next
axis, called the Bayer and Stanbridge anticlinal, is situated in the edge of Lauzon, un-
derlying the Lauzon and Farnham synclinal. The rocks are like those just described ;
and both these synclinals are represented to be very complex. In Gaspe there is
another anticlinal, and the upper division of the Quebec group soon follows. In Tilly
occurs the great fault separating the Huronian strata on the east from the fossiliferous
formations bordering the St. Lawrence river. The Huronian rocks are apparently
above the newer formations, there being an overturn. The formation coming to the sur-
face, and underlying the St. Lawrence river, is the Lorraine group. Following this are
the inferior members of the Lower Silurian, resting upon the upturned edges of the
Laurentian. These ancient strata are overturned, dipping north-westerly to the end of
the section in Bourg Louis.

36 STRATIGRAPHICAL GEOLOGY.

The Problem to be Solved.

With the preceding general statements in mind, it will be proper now
to hasten to the special task before us of unravelling the tangled strati-
graphical structure of the New Hampshire formations. That the Atlantic
gneisses differ radically in lithological features from the Adirondack
schists, is universally admitted ; that they differ more markedly from the
Paleozoic groups of the St. Lawrence and Champlain valleys will be
obvious after detailed comparisons. That there are lithological resem-
blances between the porphyritic gneiss and hydro-mica schists of New
Hampshire, with portions of the typical Laurentian gneiss and the Huro-
nian rocks, every one will admit, and, if the order of their succession in
our field of labor agrees with that in the states and provinces adjacent
to us, where the structure has been determined, we shall be justified in
believing what is suggested by the similarities in mineral composition.
The satisfactory reference of our formations to those elsewhere described,
or else the establishment of a new series of groups, is the problem before
us to be solved. We propose now to describe the rocks in detail, taking
in order each of the topographical districts into which our territory may
be naturally divided, as stated in Volume I, page 171, beginning with the
most northern, and proceeding southerly. After the presentation of all
the facts, we shall be better prepared to discuss the correspondences
between our formations and those adjacent to us. Though the field may
now seem full of perplexity and confusion, we shall undoubtedly discover
the clue to complete order, and be surprised at the simplicity of the con-
ception which has determined the building up of our stratigraphical
column.

Fig. 2. — TESCUEMACHER's figure of crystals of tin ore from JACKSON.

CHAPTER IL

GEOLOGY OF THE COOS AND ESSEX TOPOGRAPHICAL DISTRICT.

BY J. H. HUNTINGTON.

Introduction.

The geology of the country here noted embraces the northern part of New Hamp-
shire as far south as the White Mountain region, and we have also included parts of
Canada and Vermont that are adjacent.

The topography of this section has been briefly sketched in Part I, Chapter VIII, of
this report.

We have described the rocks as belonging to certain groups, — the Coos, Huronian,
and Montalban.

As there are the same general reasons for assigning the rocks in this section to these
groups as for placing similar rocks elsewhere in the state in them, to show the reason
why they are so placed would be only a repetition of what has been said ; for we see
no reason, with our present knowledge, for disagreeing with the general conclusions
reached by the state geologist. So far as tracing the boundaries between the different
groups is concerned, and making minor subdivisions, the writer is alone responsible.

The general scheme of this report is as follows :

(i) There is given a general outline of each of the groups, with their geographical
limits.

(2) We have given the locality where the rocks have been examined and specimens
have been obtained, with the dip of the strata.

(3) There will be found a catalogue of the specimens, as arranged in the state mu-
seum at the New Hampshire College of Agriculture and the Mechanic Arts.

By this arrangement, a person who desires only a general knowledge of the geology
of this section, can obtain that from the outline. A study of the dips will give a person

38 STRATIGRAPHICAL GEOLOGY.

more interested an insight into the stratigraphical relations of the rocks, while a study
of these, in connection with the specimens in the cabinet, will enable a person to ob-
tain in a short time a knowledge of the geology of New Hampshire that would require
years of study in the field. The names of the rocks that are given are for the most
part provisional, as they have been named from their most obvious physical properties,
Avithout the aid of the microscope. Where the names of individuals are referred to,
they are those found on the county map. Since the inhabitants are constantly chang-
ing, the county maps will enable a person at any time, though many years hence, who
desires to find the exact locality of specimens, to find them at once, without a long and
tedious inquiry.

An article on the drift and the economic geology of this section will be found in a
subsequent chapter.

Coos Group.

XN the western part of New Hampshire there is quite a large area
where the rocks consist of wrinkled, argillaceous schists, clay slates,
and corrugated gray micaceous sandstones. These rocks are, however,
more extensively developed in the north-western portion of the state.
Both the schists and the sandstones contain small cavities filled with
ochrey yellow powder, and frequently there are calcareo-argillaceous
bands, with harsh, arenaceous schists, and occasionally siliceous lime-
stone, which weathers to a dark, reddish brown. The area of this rock
in New Hampshire is but a very small part of its entire area, in its exten-
sion north-west in Vermont and north-east into Canada. This rock is
extensively developed in Vermont, east of the Green Mountains, espe-
cially in the central part of the state, but southward it becomes a narrow
band. Its lithological characteristics were noticed by Prof. C. B. Adams,
in his preliminary report of the geology of Vermont, and its geographical
limits were by him defined, but he made no attempt to determine its
stratigraphical relations. These rocks, in their extension into Canada,
have been studied especially by Sir W. E. Logan and Mr. James Richard-
son, and they seem to form a continuous series from the province line,
east of Lake Memphremagog, to the Bay of Chalcur. In the report of
progress of the geological survey of Canada for the year 1849-50, these
rocks were referred to the Upper Silurian. In the report of 1863 they
are described as a part of the Gaspe scries, the sandstone of which was
supposed to be chiefly Devonian. In the report of progress for 1866-69,

coos AND ESSEX DISTRICT. 39

Mr. James Richardson describes the rocks in the area between the Chau-
diere and the Temiscouata road, the boundary on the north-west being
the St. Lawrence, and on the south-east the province Kne. At St. Denis
he finds fossils of the lower division of the Potsdam. This corresponds
to the Georgia group of Vermont. Then follows what he regards as the
middle and upper division of the Potsdam ; then there is a fault, south
of which he finds the Sillery sandstone; and then, south of what he
makes an anticlinal, follow, resting on these metamorphic Quebec rocks,
the slates so well developed in the Chaudiere from St. Francis to Lake
Megantic. These last, according to Richardson, overlie the Lauzon.

The metamorphic Quebec rock of Logan, now recognized as Huronian,
occurs in New Hampshire east of the rocks just mentioned, except that
there intervene bands of schist and gneiss containing andalusite and
staurolite, which may be more recent. These Huronian rocks, as they
occur in New Hampshire, may be described as follows : Green chloritic
rocks, in which the lines of stratification are obscure. These often con-
tain scales of chlorite. Variable greenish feldspathic sandstones, with
intercalated bands of siliceous limestone. In these sandstones there are
sometimes developed large crystals of feldspar, and elsewhere they con-
tain an abundance of hornblende, and frequently epidote, argillaceous
quartzite, green chloritic schists, stratified diorites, serpentine, and some-
times soapstone. The rocks immediately underlying the Calciferous mica
schists, which contain staurolite, andalusite, and allied minerals, we regard
as a part of the Coos group. Looking over the large area occupied by
both groups of rocks just described, we find that, overlying these and
occupying beds in this rock, there are several small areas of fossiliferous
rock, which are generally referred to the Lower Helderberg. Beginning
on the south, we have the fossiliferous band at Bernardston, Mass., with
its immense crinoid stems ; and, going north, at Littleton, N. H., we have
a limestone, with brachiopods, corals, crinoid stems, etc. At Lake Mem-
phremagog, on the border of the Calciferous, we have a similar band, and
at Dudswell, on Famine river, and other localities in Quebec province, we
find fossils of a similar character. In Flagstaff, Me., there is Helderberg
limestone, associated with rocks very similar to those found at Littleton,
N. H. Sir Wm. E. Logan regarded the Calciferous mica schist as Upper
Silurian, from the fact that the fossiliferous bands were so associated with

40 STRATIGRAPHICAL GEOLOGY.

it that these metamorphic rocks seemed to be only altered strata. But
we have in New Hampshire and Maine fossiliferous rocks of Lower Hel-
derberg, resting on or associated with rocks which he referred to the
metamorphic Quebec group.

We now give in detail the lithological characteristics of the rocks of
the Coos group, and its geographical limits in northern New Hampshire.

If we draw a line from a point on the boundary, two and a half miles
east of Third lake, and have it run nearly parallel with Perry stream, con-
tinuing it south, it will cross the east end of Back lake, will pass half a
mile west of D. Blanchard's, and cross the road running along the Con-
necticut near the house formerly owned by T. Blanchard. Extending it
south through Clarksville, it will cross the Dead Water stream a mile east
of the terminus of the road that runs east through the town, then, bend-
ing a little to the east, it passes half a mile east of Alden Fletcher's in
Stewartstown, thence southward to J. Young's, near Bear rock, thence
directly south across Colebrook and Columbia, almost to Sims stream,
then, turning nearly at a right angle, it extends to the Connecticut. We
have the eastern boundary of the Coos group in the towns through which
the line is run. An extension of the line northward into Quebec province
would cross the north end of Lake Megantic. Near the mouth of Sims
stream it seems to have been crowded out by the sienite. Before follow-
ing the line where this group comes up south of the sienite, we shall
describe the rocks included in the northern section. They consist for
the most part of argillaceous schists. In places, and perhaps more com-
monly near the eastern border, the strata are so wrinkled and corrugated
that it is often difficult to determine the dip. In many places, interstrati-
fied with the wrinkled masses, are strata in which the laminae are thicker,
and, when separated, present a smooth surface. This has almost invaria-
bly small cavities disseminated through it, which are filled with a brown
powder, resulting, probably, from the decomposition of a lime mineral,
containing protoxide of iron : the lime being removed, the iron would be
converted into a peroxide, whence the brown color. This brown powder
is so abundant that it sometimes gives a coloring to the whole rock.
While more abundant in the rocks that have a regular cleavage, yet
sometimes the cavities are scattered through the wrinkled varieties. In
some cases the schist that has an even cleavage contains an abundance

coos AND ESSEX DISTRICT.

41

of iron pyrites, the cubes being half an inch or more in diameter. A
remarkable locaHty is on the east branch of Indian stream, about nine
miles north-west of Connecticut lake. On the northern border of the
Colebrook Academy grant the rock is more fissile, and approaches nearer
to a common black slate than it does elsewhere, but it contains the cavi-
ties just described, everywhere disseminated through it. Two miles
north-west from the mouth of the west branch of Indian stream the
rock becomes more micaceous, and the thin, wrinkled laminae are wait-
ing, but, what is more important, the dip changes. It is possible, however,
that it is only a fault. Northward, in Quebec province, we find both
classes of rocks just mentioned, and both have the same dip. The line
where the dip changes runs through the east part of Newport. On the
branches of Indian stream, three and a half and four miles from the
boundary, gold has been found to some extent, but it will be alluded to
more fully when we describe the drift. The rock here is the same as
that at Ditton, where gold has been so successfully washed. The rocks
of this group, which we have thus far noticed, had to be studied for the
most part while we were traversing a dense forest ; but, going south, we
come to the settled portion of Pittsburg. At Mrs. Tabor's, on Indian
stream, just east of the house where a few years ago a hurricane swept
away the forest, there is a fine exposure of the wrinkled schist. On
Hall's stream, just above the line, there is another outcrop of the same
rock, and, being near the road, it is more accessible. This rock extends
south, and it is the principal rock in the settled portion of Clarksville.
The more compact is everywhere interstratified with that which is
wrinkled and corrugated. There is an extensive area of the compact
schist just east of the road through Clarksville, a mile south of the bridge
that crosses the Connecticut. After passing the height of land in Clarks-
ville, going south, the rock becomes more calcareous, and is identical with
the formation which, in the report of the Vermont geological survey, is
called Calciferous mica schist, but it lacks for the most part the siliceous
limestone, which is an accompaniment of that rock in Vermont, except in
two or three cases, which will be noticed. It differs from the rock north
along Indian stream in no respect lithologically, except in the greater
abundance of lime. Under the bridge that crosses the Connecticut at
West Stewartstown there is a siliceous limestone in which there is a

VOL. II. 6

42 STRATIGRAPHICAL GEOLOGY,

large per cent, of lime, while on the hill east we find the wrinkled schists.
On the road just below the county farm the rock is almost as fissile as
slate, and on it are drift strias which are remarkably distinct. On Piper
hill there is a broad band of compact schist, containing cavities filled
with a yellowish brown powder. The same rock southward outcrops on
Sargeant hill. Passing into the valley east, at the saw-mill on Bishop's
brook, we have a good exposure of the schist containing lime as an in-
crustation. On account of the fragile nature of the rock and the lime
incrustation, this schist everywhere readily decomposes. Although the
ledges are often near the surface, it is seldom that they are seen except
along the streams, and then frequently the harder portions are mingled
with those that are partially decomposed. This is particularly noticea-
ble in the vicinity of J. Poor's, but in many places elsewhere in Stew-
artstown it can be seen. North of J. Poor's we found in the fragments
of the schist the mineral ankerite, also galenite. On the farm of Mr.
A. Fletcher we found the ankerite in a ledge ; and possibly a few blasts
might develop galenite. As this calciferous rock so readily decom-
poses, it is constantly supplying the lime that is necessary to produce a
fertile soil ; hence, also, the scarcity of boulders in the towns where this
rock is found. A fine example of the wrinkled schist, interstratified with
the more compact varieties, can be seen near J. M. Kidder's, The east
part of Stewartstown, as well as Clarksville, is still covered by the pri-
meval forests ; yet there are probably very few places in any state that are
more inviting, on account of the fertility of the soil, than is this section
of New Hampshire.

Colebrook, except a small area in the south-west corner of the town,
and a strip on the east side, is composed of the schist containing lime.
The high hills north-east from Colebrook village, and extending east
along the Mohawk, are characteristic of this group of rocks. On Beaver
brook, at the falls, we find siliceous limestone, which is found so abund-
ant in this group in Vermont. The argillaceous schists, with which the
calciferous strata are interstratified, extend south to Sims stream, and
east nearly to the road running north and south through East Columbia.
In the north-west corner of Columbia, fifty rods north-east from the Jude
Fairnam place, there is a gray and drab colored limestone, interstratified
with the schist, "the strata running north-east and south-west, and in-

coos AND ESSEX DISTRICT. 43

clined to the south-cast 55°. The bed is 30 feet wide, and will furnish a
weak lime, since it contains only about two thirds of its weight of pure
carbonate of lime. If burnt very carefully, it slacks with difficulty into a
granular mass, but if the heat is raised to whiteness, it melts into a slag
or glass, owing to the formation of silicate of lime."* The extensive
deposit of marl in Lime pond will be noticed under alluvial deposits.

Along the Connecticut, south of Sims stream, there is a small area of
this group of rock. It begins in a point one fourth of a mile south of the
stream. The outcrop of the rocks can be seen from the road, and where
it begins the strata seem to have been pushed to the west, as the strike
will readily be seen to run in a different direction from what it does a few
rods south. The area increases in width as we go southward, until it is
about two miles wide; then it becomes narrower, and, in the south part of
the town, it is not far from one mile. The rocks are micaceous and argil-
laceous schists and siliceous limestone. Near Mrs. Ross's the limestone
is noticeable from the road, on account of its dark color, as, in weathering,
the lime is removed, and only the siliceous portion of the rock is left.

In the north-east part of Pittsburg, in the area between the Connecti-
cut and the Magalloway, there is a band of the Coos group. These rocks
form the water-shed between the head waters of these streams ; and it is
a very noticeable fact, that these Coos rocks here form a synclinal axis,
and both on the east and west we have Huronian rocks, which here con-
sist of greenish siliceous schists with epidotic nodules.

In Vermont, opposite Columbia, the Coos group is developed. It ex-
tends southward, and probably terminates near the south line of Bloom-
field. Northward, it outcrops in Canaan, and extends west to Little
Averill pond, where it is interrupted by an intrusive granite, but it
appears again in Holland, whence it extends southward through Ver-
mont. An interesting area of this group is found in the south-east part
of East Haven, and it outcrops again in the vicinity of the church in
Granby. In both these localities it forms beds in the older rocks.

Where Specimens were Collected, and the Dip of the Strata.

At the north end of Lake Megantic, in Quebec province, the strata,
both of the Coos and Huronian groups, stand nearly vertical. The rocks

* Jackson's final Report, p. io6.

44 STRATIGRAPIilCAL GEOLOGY.

of the Coos group here are mostly yellowish ochrey sandstones, that fre-
quently contain crystals of pyrite. With the sandstone there are bands
of a fissile argillaceous schist, in places not distinguishable from common
black slate. On the border of New Hampshire, in Ditton, the rock is an
ochrey argillaceous schist ; and at the gold mines the strata dip S. 44°
E. 70°. In R4 L20 the rock is a mica schist, and dips N. 26° W. 68°.
Going west to Newport, the rocks become decidedly calciferous. In R
12 L19 the mica schist dips N. 22° W. 65°. Between the church and
North river bands of slate are interstratified with bands of calciferous
mica schist, that dip N. 21° W. 72°. There are numerous outcrops of
the same rocks, in the vicinity of East Clifton, that dip N. 41° W. 64°.
In the south part of Clifton, in the vicinity of Charles Sawyer's, the rocks
are less micaceous and more fissile. In Hereford, a mile north of J.
Lambert's, the rock is an argillaceous schist, and it dips S. 36° W. 43°.
In the south part of Hereford, near Hall's stream, there is a corrugated
and wrinkled argillaceous schist. At one point it dips N. 66° E. 80°,
and, a few rods distant, it dips in the opposite direction. Along the
lower part of Hall's stream this rock is everywhere nearly vertical. In
Auckland, half a mile north of the west branch of Hall's stream, the argil-
laceous schist dips N. 18° W. 65°, On the boundary, at the head of
Hall's stream, the rock is an arenaceous clay slate, and dips N. 46° W.
65°. On Hall's stream, opposite the west branch, an argillaceous schist
dips N. 22° W. 74°. Crossing over from Hall's stream to the west branch
of Indian stream, the rdfcks have a dip quite uniform, which is N. 36° W.
from 70° to 80°; and the difference in texture is slight, everywhere an
argillaceous schist, in places more fissile than in others, and occasionally
containing an ochrey powder. The same rock, with a dip N. 36° W. yS°,
was seen two miles up the west branch of Indian stream. Between Hall's
and Indian streams, on an old "tote "-road from Pauquetteville in Here-
ford to M. K. Day's, the rocks arc as follows: Half a mile east of Hall's
stream there is an argillaceous schist; the strata stand nearly vertical,
sometimes having an easterly and then a westerly dip. A mile from
Hall's stream the rock is an ochrey argillaceous schist, and dips N. 62°
E. 65''. Between this and Day's the rocks are argillaceous, but frequently
contain some mica ; and, everywhere they were examined, the inclination
of the strata was nearly uniform with the last. In the Colebrook Acad-

coos AND ESSEX DISTRICT. 45

emy grant, north of this, numerous observations were taken; but, as a
section giving the rocks in detail across the grant will be described,
these observations are omitted. It will be noticed that the dip of the
rocks, in the country between Hall's and Indian streams, is almost uni-
formly to the west. This seems to be due to a fault.

Between Indian and Perry Streams.

On some of the most northern branches of Indian stream, where gold
has been obtained by washing, the rock is an argillaceous schist, that is
sometimes ochrey. The dip, three and a half miles north of the east
branch, is S. 34° E. 70°; two miles north, S. iS"" E. 75°. On the east
branch, about a mile from Vv^here it flows into Indian stream, the rock is
an argillaceous schist ; but interstratified with it are bands of a hard mi-
caceous schist, which dips S. 22° E. 80°. On the old "tote"-road, from
the forks of Indian stream to Connecticut lake, a little more than a mile
from the forks, the rock is an ochrey argillaceous schist, some of the
strata showing hme incrustations. The general dip is N. 54° E. 75°.
Toward Perry stream the schists are micaceous, and the dip, three
fourths of a mile west of this stream, is N. 6S° E. 70°. These rocks
extend southward; and, near M. K. Day's, a wrinkled argillaceous schist
dips N. 50° E. 73°. North of Bowen pond, and west of H. H. Johnson's,
there is an argillaceous mica schist. The strata are bent in many places,
but the general dip is N. 88° E., and the inclination is exceedingly vari-
able. Almost directly south, near H. B. Schoff 's, the rocks are decidedly
arenaceous, and have the character of the hard bands that are inter-
stratified with the Calciferous mica schist; the dip is S. 44"" E. 65°.
These hard bands extend southward, and outcrop on the road from Indian
to Hall's stream. In the extreme northern part of Pittsburg, and di-
rectly east of Third lake, there is a small area of the Coos group, that
appears to form a synclinal axis in the Huronian. At one point, half
a mile from the lake, the dip is S. 34° E., variable, and in places the rocks
are so bent and contorted as to suggest that this basin of newer rocks
has been compressed by the older and harder surrounding Huronian.

These are the chief outcrops of the Coos group in Pittsburg ; but there
are still two outcrops in the south part of the town that deserve notice.
Between the church and the road, going north to D. Blanchard's, the

46 STRATIGRAPHICAL GEOLOGY.

rocks resemble more the Calciferous than those found elsewhere in the
town, and they dip S. 54° E. 75°, though the dip is by no means uniform.
The other outcrop is just west of Mrs. E. B. Tabor's, where the rock is a
wrinkled argillaceous schist, and the strike is N. 41° E. The bent strata
sometimes make the dip quite uncertain. This wrinkled argillaceous rock
outcrops in Hereford just north of the Vermont line, where it has both an
easterly and westerly dip, and it crosses over into Stewartstown at the
mouth of Hall's stream. Near the village of West Stewartstown, on the
south-east, the argillaceous schist dips N. 88° E. 80°, and, a mile east of the
village on the road south of the Connecticut, the same rock outcrops, but
more wrinkled than at the village, and dips N. 65° E. 80°. This rock,
with the exception of quartz, retains the drift striag better than any other

in the state.

Coos Group in Clarksville.

On the road that runs south through the town, from the Connecticut
nearly to the height of land, the rocks are decidedly arenaceous, and have
an easterly dip. Near the eastern limit of the Coos, in the vicinity of
W. W. Chamberlain's, the rock is a wrinkled argillaceous schist, and dips
S. 41° E, 75°. The strata being so nearly vertical, and the rock so simi-
lar to that at West Stewartstown, and the intervening rock so decidedly
a calciferous mica schist, it suggests very strongly the idea of a syncli-
nal axis. At J. Gethercole's the rock is a calciferous mica schist, and
dips S. 40° E. At G. Tirrell's, very near the house, the rock is an argil-
laceous mica schist, and dips N. 66° E. 82°; but north of this there is
an intrusive diorite. The dip of the rocks elsewhere will be given on
the section passing through the town.

Stewartstown.

North-west of a line drawn from near the mouth of Bishop's brook, to
a point on the Connecticut just south of C. L. Morse's, the rock is a
wrinkled argillaceous schist. The central part of the town is a calcif-
erous mica schist. On the west side of Piper hill the rock is an ochrey
mica schist, and it has an easterly dip; but here, as southward on the
road towards Colcbrook, the strata are quite irregular. On Sargent hill
the calciferous mica schist, with hard, compact arenaceous bands, dips
S. 58° E. 68°. At a saw-mill, a little north of west from the "Hollow,"

coos AND ESSEX DISTRICT. 47

the rock is a calciferous mica schist. Directly north, at J. Poor's, the
hme, as an incrustation on the schist, is very abundant. Fragments of
quartz in the soil are also very abundant, and these sometimes contain
galena. Near M. Fletcher's the rock dips S. 56^ E. 62°. The character-
istic calciferous mica schist continues east nearly to M. Harriman's,
where it becomes somewhat arenaceous, and dips S. 51° E. 64°. At A.
Fletcher's, which is farther east and on the confines of the forest, we
find argillaceous bands, with argillaceous mica schist that dips N. 82°
E. 70°. This is near the eastern limit of the Coos group. South, at
J. M. Kidder's, the argillaceous schist resembles that east of Dead Water
in Clarksville ; here it dips S. 44° E. 80°. At J. Young's the rock is
argillaceous and fissile. The calciferous mica schist outcrops on the
road from Bear rock to South hill, and dips S. 46° E. 75°.

Co

LEBROOK.

The principal rock of the town is calciferous mica schist. On the
road up Beaver brook, near J. E. Stevens's, the dip is S. 54° E. 60°. At
the Falls there is a band of siliceous limestone. At D. Heath's there
are numerous outcrops of calciferous mica schist. North-east of Factory
Village the calciferous mica schist dips S. 50° E. 78°.

HuRONiAN Group.

East of the line limiting the Coos group, in the northern part of the
state, there are two prominent bands of rocks that belong to the Huro-
nian. The first is confined chiefly to this section, and consists of strati-
fied diorites, diabase, hornblende rocks, greenish schists, containing
nodules of epidote, arenaceous and chloritic schists. This band of rocks
begins, on the south, in Columbia, and extends northward until it passes
out of the state near Third lake. Where this group of rocks begins in
Columbia the green schists predominate, but in Colebrook, just west of
H. Gould's, the diorite begins, and northward it is accompanied either by
the green or the arenaceous schists. The most prominent rock of this
group is the diorite. In many places it appears to be a massive rock,
without any marks of stratification, but elsewhere it is plainly stratified,
and interstratified with it is a whetstone grit or arenaceous sandstone
schist. It forms the ridge in Colebrook known as Bear rock. In Stew-

48 STRATIGRAPIIICAL GEOLOGY.

artstown it can be seen half a mile east of Alden Fletcher's. In
Clarksville it outcrops a mile west of J. Gethercole's. In Pittsburg it
forms a prominent ridge on the east of the rock, where it leaves the
Connecticut river and turns northward. From this point to Connecticut
lake the outcrops are frequent, also along the road north of the lake, and
it forms the high hill west of Round pond. Going north there are nu-
merous outcrops along the old "tote "-road to Third lake, and north of
this lake it is the principal rock of one of the high points on the bound-
ary. It is a dark gray rock, often has a greenish tinge, and, in some
specimens, the hornblende is quite distinct. It is extremely hard, as
every one who has attempted to work it will testify. In some localities
it decomposes by the action of the atmosphere, probably on account of
the presence of lime, for in some places it contains a sufficient amount
of lime to effervesce when acid is aijplied. In no part of New Hamp-
shire is there better pasturage than where this is the prevailing rock;
but frequently, on account of the great number of boulders, the land is
not desirable for tillage. The following analysis by Prof. Seely, though
probably imperfect, shows the chief constituents of this rock:

Silica, 49-51

Protoxide of iron, 21.42

Alumina, 14.88

Lime, 8.52

Magnesia, 4.86

99.19
This rock forms nearly all the boulders of Pittsburg east of its outcrop,
and they have been carried far to the south-east, one having been seen
east of the Magalloway. It contains very few veins, and those seen were
of vitreous quartz.

The green schist does not seem to be continuous, but where it does
not outcrop it may be concealed by drift. It is a prominent rock in the
south part of Columbia, just east of a starch mill on Sims stream. In
Colebrook it outcrops on the road west of Young's mill, then on the road
near C. I". Hardy's. In Pittsburg it is a common rock, and it comes in
contact with the argillaceous schist on the road along the Connecticut,
just before the road turns north. It is the rock of the east end of Con-
necticut lake, and it can be seen on the two small islands of that lake, as

coos AND ESSEX DISTRICT. 49

well as on the adjacent shore. On the farm north of the lake, formerly
owned by E. Day, ledges of this rock are very prominent, and it contains
numerous nodular masses of epidote, and, not unfrequently, there is lime
associated with the epidote. North of Second lake there is a considera-
ble area occupied by it.

The whetstone grit in the south is first seen north-west of Bear rock,
near T. Paul's. Although the cleavage of this rock is not such that it
can be easily wrought for scythe-stones, yet, on account of its excellent
grit, farmers sometimes get them here, as also in the vicinity of Connec-
ticut lake. Along the line of the diorite the whetstone grit frequently
outcrops. In Clarksville it is a common rock in the woods east of the
settlements. In Pittsburg, on the farm formerly owned by J. P. Quimby,
this schist is interstratified with the hornblende rock ; and in the forests
south-east of J. T. Amy's there are several ridges where this is the un-
derlying rock, and some of the outcrops present a surface of twenty or
thirty feet, nearly perpendicular. West of Connecticut lake, for a mile,
there are several places where there are ledges. Often the drift striae
are remarkably distinct, and many can be seen in the vicinity of the out-
let of the lake. Northward, this rock appears in outcrops all the way
to the boundary. There are prominent ledges of it on the west shore of
Third lake, where it appears massive enough for grindstones, while north-
ward, on the boundary, the cleavage is such that whetstones could be
easily wrought.

All the rocks which we have described as embraced in this belt have
their strata at a very high angle, but sometimes they dip towards the
east, and, again, they dip westerly. The high angle at which they dip,
the disturbed strata, and the character of the rock indicate that they are
older than the rocks on the west ; — but this will be more fully discussed
elsewhere. East of the band of rocks just described there is a large area
in which are found hydro-mica schists, serpentine, diorite, quartzites, and
indurated schists. These rocks are not confined to New Hampshire, but
they extend northward, and constitute the metamorphic Quebec group of
the Canadian geological survey. At the extreme north-east corner of
the state, at Crown monument, we find a fine-grained mica schist. Two
miles south-west of Crown monument there is a band of serpentine, a
rock exceedingly rare in New Hampshire, but which is here found in the
VOL, II, 7

50 STRATIGRAPIIICAL GEOLOGV.

large basin from which flow so many streams that form the Magalloway.
It is of a greenish black color, mottled with olive green. It is asbesti-
form where joints occur, and weathers to a reddish brown. It is un-
doubtedly a metamorphic rock, and probably formed from preexisting
silicates. There is also in this basin a green schist ; but going south-east,
the ridge that forms the water-shed between the Magalloway and Con-
necticut is composed of gneiss. Following this ridge southward, we
come to Mt. Carmel, which is a stratified diorite ; the flanks of the ridge,
running north-east toward the Magalloway, are gray siliceous schists.
Going south-west from the water-shed just mentioned, we pass over
Stubb hill, the ridge of Bosebuck mountain. Diamond ridge, and Magal-
loway mountain. All of these are composed of siliceous schists. Some
of these schists have the appearance of a dark quartzite, but particularly
on the west, in the joints, they contain lime as an incrustation.

Lyman Group.

On the line of Maine and New Hampshire, between the heights of
Mt. Carmel and Mt. Prospect, there is an axis. The rock is a gray sili-
ceous schist, which in places approaches novaculite. Though the strata
are nearly vertical, yet on Mt. Carmel the dip is northward, and on Mt.
Prospect it is southward. The distance between these points is 920 rods.
In consequence of the southerly dip on Mt. Prospect, we have a mountain
with a precipice almost perpendicular on the north side, something ex-
ceedingly rare in New Hampshire. On Mt. Bosebuck, about the same
distance south of Mt. Prospect that Mt. Carmel is north, the dip is north-
erly ; so that Mt. Prospect, with Mt. Bosebuck, forms a syncinal axis, or
there is a series of folds, and there has been an immense downthrow
north of Mt. Prospect. These rocks correspond to the Lyman group,
which is the upper member of the Huronian. Between Mt. Carmel and
Mt. Prospect there is a deep valley, and on the Little Magalloway, that
flows through it, there is a band of clay slate ; while near Mt, Carmel,
and forming the east end of the mountain, there is a greenish, indurated
rock, probably diorite. While the strike is only a little south of east on
the state line, as these rocks extend west and south, the strike becomes
more southerly. On the old "tote "-road, from Connecticut lake to the
Magalloway, it attains a great width ; and the general strike is N. 20° E.

coos AND ESSEX DISTRICT.

51

On Diamond ridge the rock is very much jointed. It may be the same
as the rock northward, only more indurated, but as the same rock occurs
on Magalloway mountain, some two and a half miles to the south, and
dips in an opposite direction, this may be an ^ ^^ ^ 2,

island of older rocks. A small area of a gneissic | 5
rock between the two points also very strongly S ^
suggests the same thing. Almost directly south
from Magalloway mountain, about two miles, on
a branch of the Little Dead Diamond, there is
an outcrop of clay slate, but, it is so intimately
associated with the gray schist, it is quite evi-
dent that they are stratigraphically the same.
The gray siliceous schist is found on the west-
ern slope of Mt. Pisgah, while to the south the
slate outcrops on the branches of Cedar stream
in a synclinal axis. On the water-shed between
Cedar stream and the Swift Diamond there are
argilk jeous bands. A short distance south of
this water-shed the gray siliceous schist is the
only rock, but as it extends southward it changes
somewhat its physical characteristics. The rock
at Dixville notch differs from the gray siliceous
schist northward more in its cleavage than in
any other characteristic. The general features
of the Notch have already been described.* The
rocks here form a monoclinal axis, and the strata
are nearly vertical. A peculiar cleavage causes
it to split into longitudinal fragments, and leaves
high vertical walls on the sides of the Notch.
At one point there is a good profile, the outline of which is seen in Fig,
10. Where the schist comes in contact with the granite, on the east side
of the Notch, it shows clearly the effect of pressure. This band of rocks
below the Notch has a south-easterly trend. The argillaceous rock in
Millsfield, east of the ponds, belongs probably to this group.

* Vol. I, p. 641.

52

STRATIGRAPIIICAL GEOLOGY.

South-west of Millsfield ponds, within the limits of Millsfield, the rocks
^ consist chiefly of very dark sihccous slates, while
c south-west of Newell brook it is followed by gray
n gneisses of the Montalban group. East of the An-
° droscoggin, on the line of Errol and Cambridge, we
I have the light gray siliceous schist characteristic of
!^ the Huronian. In the central part of Dummer, im-
^ mediately east of the Androscoggin, there is an out-
's crop of chlorite and siliceous schist ; but west of the
< river, especially in the valley of the stream that flows
Z from Dummer jDonds, there are no outcrops of rock,
"g but a mile south-west of the Dummer ponds there
^ are many extensive outcrops of gray siliceous schist.
S At West Milan it is interstratified with hornblende
; schist. It outcrops a mile and a half south-east of

o

•^ West Milan, and its extension west to Stark water-

I g- station gives to the rock here a great width, but its
^ ^ nearly vertical state suggests that it is made up of

I I numerous folds, as we can trace both synclinal and
■g s anticlinal axes. The western group of Huronian
_■ rocks begins near the north line of Stratford, where
I they consist of dark siliceous schists. Extensive out-
-^ crops are found at the head of Bog brook, along the
^ west side of Percy peaks, on the south of Potter's
I pond in Stark, the east side of the Devil's slide and
", Mill mountain, on the east side of the hill south-east
S of Groveton, and between Mt. Lyon and the Pilot
I range. On the Connecticut, in the south part of
= Stratford, is the light gray siliceous schist, and this
^ extends eastward and outcrops on Nash stream.
I From near the north line of Northumberland, and
^ southward through Lancaster and terminating in the
I north part of Dalton, the rock consists of feldspathic
■£ chloritic schists. These frequently have hornblende

c

^ and epidote as accessory minerals. In Dalton the

coos AND ESSEX DISTRICT. 53

Huronian rocks consist of light gray siliceous schists and clay slates;
but the band of argillaceous sandstone of Dalton mountain is probably
a much newer rock.

Other IIukoxian Rocks.

There is a band of rocks extending from the Magalloway river through
the Academy grant, and occupying a large area in the Dartmouth College
grant, which consists chiefly of light gray schists. It is frequently, how-
ever, of a dark gray color, and sometimes it passes into shades of olive
green, and it resembles the hydro-mica schists of Vermont. Its limit on
the state line north is not known, but south it extends about a mile below
the north-east corner of the College grant. Near the south line of the
Academy grant, and west of the Little Dead Diamond, it forms high hills
and ridges, often jutting out in high overhanging cliffs. The Little Dead
Diamond, in places, has worn deep channels in this rock. One of these,
not far from the north line of the College grant, is from twenty to thirty
feet deep, and extends nearly four hundred feet along the stream. Here
the rock contains an abundance of small crystals of magnetite. It ex-
tends south in the College grant nearly to the mouth of Linnell brook.
Its south-western limit has not been determined. Everywhere the strata
are nearly vertical, but they are generally inclined to the west. Succeed-
ing this rock on the south-east is a mica schist containing garnets. On
Linnell brook the garnets are of a deep red color, often translucent and
very abundant. On the Swift Diamond the rock is more gneissic, and
contains staurolite. The crystals are half an inch thick, and from one
and a half to two inches in length. On the high hills, near the Magallo-
way and north of the Swift Diamond, the mica schist, with garnets and
staurolite, is interstratified with hornblende schist, and the strata stand
nearly vertical. On Mt. Dustin the schist contains staurolite. The crys-
tals are small, being from one to two lines thick, and three fourths of an
inch in length. Eastward, extending perhaps a mile east of the College
grant, we find mica schist, and southward it is found west of Wentworth
pond. Between Aker's pond and the Androscoggin the outcrops of mica
schist are very numerous. Between the road to Upton and Umbagog
lake, particularly towards the south end of the ridge, the schist is very
much contorted. West of Bragg's bay, and south of Clear stream, the

54

STRATIGRAPinCAL GEOLOGY.

rock in Errol is entirely mica schist, often containing garnets, and the
strata everywhere are nearly vertical. The mica schist extends into
Millsfield, but east of Millsfield ponds there is a band of schist that prob-
ably belongs to a newer group. This is perhaps half a mile in width.
West of the ponds the mica schist again outcrops ; and the dip varies
greatly as we approach the granite in the west part
i! of the township. The mica schist of the character
% just mentioned does not extend south of Millsfield in
I this section of the state.

J HuRONiAN IN Vermont.

I Directly south of North Stratford, on the west of

•3 ^ the Connecticut, the rocks consist of dark siliceous
J ^ schist, that sometimes contains crystals of a rare va-
I ■; riety of andalusite. Through Maidstone, along the
^ 2 Connecticut and southward to Waterford, we find the
"c § same rock as that described as occurring in North-

0 '■s umbcrland and Lancaster. West of this rock, in

.'i a Guildhall, we find the gray siliceous schists that
i; -5

1 jS extend southward through Lunenburg, and they ter-

"S g minate in Concord.

M 3

I ^ Atlantic Series.

I -^ We give here the outline of the Atlantic series.
f The rocks belong chiefly to the Montalban group,
I While these rocks are developed very extensively in
I New Hampshire, they occupy a very large area in
= Maine and a small but important area in Vermont.
i For the area in Maine, the reader is referred to the
"5 preceding chapter. In New Hampshire its most
^ northern outcrop is at the southern extremity of
Umbagog lake, where the rock is a gray micaceous gneiss and horn-
blende schist. It extends southward through the east part of Cam-
bridge. In Success the Montalban group gradually extends eastward.
Southward, the rocks in the whole area of the towns of Shelburne and
Gorham, except in the north-west corner of the latter, arc Montalban.

coos AND ESSEX DISTRICT.

55

The gray micaceous gneiss of the Montalban group outcrops
mer, south-west of the ponds, and there is a considerable area

The relation of these rocks to those adjacent is shown in Fig.

The common gneiss of Milan, which is prob- ^

ably an older rock than that just mentioned, has s-

its most northern outcrop on the Androscoggin, 'i

near the north line of the town. Its eastern ^

limit is in the extreme south-east corner of the r.

town, and its western limit is on the Grand Trunk =.

Railway, a mile above the Milan water-station. |

A dark gneiss, that sometimes contains horn- |

blende and epidote, outcrops two miles above ~

Milan water-station, and extends northward west |

of Milan hills. A similar rock outcrops at Berlin x

falls. The common gneiss outcrops at Jefferson i.

hill, and it is quite probable that it forms a con- -;

tinuous outcrop through Berlin to Milan. There s-

are several outcrops on the road from the Waum- % =

bek house to Lancaster, and it extends to within ^ |

a mile of the village; thence it extends souther- |' I'

ly, and sweeps around the south-east base of Mt. 3 i

Pleasant. Its western limit southward in Lan- " i

caster is near Blood pond. It occupies a great i

part of the town of Whitefield, and the extreme l^

east part of Dalton. |

Vermont. %

The Notch mountains in Brunswick are well-
marked rocks of the Montalban group. The
rocks of Bluff mountain, north-west of Island
pond, are probably Montalban, but they are sep-
arated from Notch mountains by an extensive
area of intrusive granite. South of Notch moun-
tains there are outcrops of the Montalban at
Maidstone lake. North-east, between the Mont-
alban and the Connecticut, there is a small area

in Dum-

in Odell.

5-

n

P H 5

56 STKATIGRAPHICAL GEOLOGY.

of intrusive granite, which, in lithological characteristics, corresponds to
the area west of the Montalban group in the valley of the Ammonoosuc.

Where Specimens were obtained, and the Dip of the Strata.

At Crown monument the rock is an arenaceous schist, that dips S. 79°
E. 'j^^ . On the state line, a mile and a half from Crown monument,
there is a greenish siliceous schist that dips S. 82° E. 65°, The rock,
two and a half miles south-west of Crown monument, is serpentine, but
the strata are quite obscure. Across the boundary in Chesham, in
R. Ill, in L. 4, 6, and 7, there is an arenaceous sandstone that dips N.
70" E. 20°. This rock forms the boundary north of the lake which is
the source of the west branch of the Magalloway. At Magalloway lake,
which is not far from three and a half miles south-west of Crown monu-
ment, and less than half a mile from the boundary, the rock on the south
side is a mica schist, that dips N. 41° E. 56°. At the outlet of the lake
the dip is N. 39° E. 'j6°. Four rods from the outlet there is a cascade
that has a fall of twenty feet. Three fourths of a mile from the lake
there is a greenish mica schist, the strike of which is N. 38° E. The
dip is exceedingly variable, but westerly. Passing" over the Coos group,
going south-west, we strike Huronian rocks in the vicinity of Third
lake. On the west shore of this lake the arenaceous schist dips N. 42°
E. 80°, but the stratification is quite indistinct. On the south shore of
the lake there is a green siliceous schist, that dips N. 50° W. 85°; and
on the east there is a greenish, stratified diorite. North, on the water-
shed that is the boundary between the state and the province, the arena-
ceous schist splits into thin laminse, is somewhat variegated, and the strata
are vertical. The highest part of the ridge is diorite, which forms cliffs
of considerable height. South-west, one fourth of a mile from the lake,
the diorite outcrops, and three fourths of a mile, the arenaceous sand-
stone, which dips N. 28° E. 80°. On the old "tote "-road, a mile and
a quarter from the lake, the diorite outcrops, and dips N. 40° E. 78°.
A mile and a half south, on the north border of a tract where there
was a hurricane many years ago, the diorite outcrops, while fifteen rods
south the schist appears, and dips N. 40° E. ^6°; and forty rods south,
where the hurricane stopped, the diorite again outcrops. Between the
"tote "-road at this point and Perry stream the diorite alternates with the

coos AND ESSEX DISTRICT. 57

arenaceous sandstone schists, which, near Perry stream, dip N. 36° E.
75°. Southward along the old "tote "-road the diorite alternates with the
schist. The general dip is N. 34° E. yS'^, and both rocks are quite alike
in texture, except that for a mile and a quarter, a little east of north from
the Fletcher place, the diorite is more schistose than along the "tote"-
road. The dip here is N. ^y° W. 75°. West of Round pond there are
immense masses of the diorite. The high hill to the west and north-west
is composed of diorite and arenaceous sandstone schist. The schist on
the north side of the hill dips N. 48° E. 78''. This extends twenty-five
yards ; then a band of diorite has a width of five hundred yards. This
is succeeded by a schist that dips N. 38^ E. 85°.

NoilTHWARD.

We have already called attention to the fact that the green chloritic
schist is intimately associated with arenaceous sandstone schist. Two
and a half miles above Second lake, near the Connecticut, the arenaceous
schist dips N. 26° E. 82°. Towards Second lake, but to the west on
Cobble hill, where the arenaceous schist is largely developed, the dip is
N. 47° W. 68°. Near the lake, south-east of Cobble hill, the same schist
dips S. 50° E. 22°, thus forming an anticlinal axis. A mile and a half
north of Second lake, between the Connecticut and East inlet, there is a
ridge of green chloritic schist, that dips N. 50° W. 6S°. On a hill south-
west of the lake the same schist dips N. 47° W. 68°. In the small area
of green chloritic schist on the head waters of the Magalloway, east of
the Coos group, the rock dips S. 47° E. 65°.

In the gneissic area on the ridge north-west of Mt. Carmel, on account
of the jointed structure of the rock masses, it is difficult to determine the
dip; but, as there is a similar area west of Parmachena lake, it is quite
probable that this is a lower member of the axis embracing Mt. Carmel,
Mt. Prospect, and Mt. Bosebuck.

On Spring hill, two and a half miles east of Second lake, a gray sili-
ceous schist dips N. 57° W. 70°. On the Little Magalloway river, three
fourths of a mile from the state line, an argillaceous schist dips S. 31° E,
80°. The same distance north of this stream, towards Mt. Carmel, the
schist dips N. 48° W. 65°. A mile and a half north of the stream the

58 STRATIGRAPHICAL GEOLOGY.

gray siliceous schist dips N. 24° W. 80°. On Mt. Carmel, at the west
end, the dip is N. 41° W. 75°. On the summit a greenish, stratified dio-
rite schist dips N. 48° W. 78°. On the north side a gray siliceous schist
dips N. 44° \V. y8°. On the ridge extending north-east from Mt. Carmel
the rock is a gray siliceous schist, the general dip of which is N. 35°
W. 80°. On Mt. Prospect the gray siliceous schist dips S. 25° E. 82°.
On the old "tote "-road from Connecticut lake to the Magalloway, seven
miles from the former, a gray siliceous schist dips S. 53° E. 80°; six
miles and a half from the lake, S. 82° E. y6°; four and three fourths
miles, a siliceous schist, with bright yellow mica, S. 30° E. 68°; four
miles, a greenish gray siliceous schist, S. 20° E. 48°; a mile and a half,
a green chloritic schist, N. 62° E. 78°. Nearly a mile south of the last,
and two miles from the lake, the same schist dips N. 53° E. 58°. On the
islands, near the east shore of the lake, a green chloritic schist dips N.
60° W. 65°; the same schist, three fourths of a mile a little south of west
of the lake, dips N. 60° W. 75°. On Magalloway mountain the rock is
chiefly a siliceous feldspathic schist, that dips N. 48° W. 70°; and on the
east side the fragments have fallen down so that there is a steep slope,
having an area of several acres, on which there is no vegetation except
lichens. On Diamond ridge the rock is the same as on Magalloway
mountain, but it is everywhere cut by numerous joints, and has a dip of
N. 70° E. 85°. On a low ridge, about ninety yards from the Little Dia-
mond, between Diamond ridge and Magalloway mountain, the dip is N.
82° W. y6°. The rock of Bosebuck and Stubb hill is a gray siliceous
schist. On Stubb hill the dip is N. 50° W. 65°. A mile and a half
south-east of Magalloway, on the Little Diamond, the gray siliceous
schist dips N. 60° W. 80°, and, farther south, it dips N. 72° W. 75°. A
little west of south from Magalloway mountain, on a branch of the Little
Diamond, are the falls described in Volume I, page 641. At the top of
the falls the rock is a gray siliceous schist, and dips S. 75° E. 85°. At
the base of the falls the clay slate, with pyrite, dips S. 80° E. 65°. These
rocks, with those on the Little Diamond, form a synclinal axis. To the
south-west towards Mt. Pisgah the gray siliceous schist dips N. 85° W.
72°. On the west side of Mt. Pisgah are gray siliceous schists, which
dip N. 85° W. 82°; then, on the western slope of Mt. Pisgah, the rock is
somewhat argillaceous, probably Coos, and dips N. 52° W. y6°. In the

coos AND ESSEX DISTRICT. 59

valley of Cedar stream, between Pisgah and the Connecticut, an argilla-
ceous schist, passing into clay slate, forms a synclinal axis.

Connecticut Lake and Southward.

At the north end of the lake, near the house formerly owned by E. Day,
the rock is a chloritic schist, which dips N. 28° E. 85°. At A. S. Hug-
gins's, we find diorite. Half a mile west of the Col. S. Huggins place the
arenaceous sandstone schist dips N. 47° W. 75°. A mile west we find
diorite, and, at S. K. Danforth's, the arenaceous schist. At D. Day's
there is diorite, and towards R. W. Danforth's there is a green chlorite
schist which dips N. 48° E. 72°. At the outlet of Connecticut lake an
arenaceous schist dips S. 80° E. 50°. At the saw-mill on Perry stream
a chloritic schist dips S. 65° E. 75°. The diorite and arenaceous schist
extend southward along the road toward Canaan, Vt. West of J. W.
Heath's and J. P. Quimby's there are extensive outcrops of arenaceous
schist, with easterly dips. There are prominent ledges of diorite on the
road south of the red school-house.

East Part of Clarksville and the Academy Grant.

Between J. T, Amy's and Cedar stream, going south-east, the rock is
an arenaceous sandstone schist. Two and a half miles south-east of
Amy's we find a siliceous schist, approaching quartzite, that dips S. 62°
E. 85°; four and a half miles, a similar rock, but somewhat gneissic, dips
W. 82°. The remaining rocks of this area will be noticed in describing

the section.

Dartmouth College Grant.

West of the Little Dead Diamond, on the north border of the grant,
there is a hydro-mica schist. On Linnell brook, a mile from the mouth,
the same schist dips N. 38° W. 75°. South, a fourth of a mile from the
mouth of the same brook, there is a mica schist, containing a great quan-
tity of bright iron-alumina garnets, which dips N. 35° W. 60°. The line
between the hydro-mica schist and mica schist, on the boundary between
Maine and New Hampshire, is about a mile south of the corner of Dart-
mouth College grant. On the Magalloway river the hydro-mica schist
outcrops seven miles above Wilson's mills, and, with the exception of a
gneissic area at Parmachena lake and an argillaceous sandstone schist

60 STRATIGRAPHICAL GEOLOGY.

at Little Boys' falls, the outcrop seems to be continuous at least as far
north as opposite Mt. Kent. The dip is westerly where observations
were made on the Magalloway. On the east line of the College grant,
on a ridge a mile south of the north-east corner of the grant, the rock
is a mica schist, with garnets, and dips N. 85° W. 70°, Along the ridge
of Half Moon mountain, with the mica schist, there are bands of horn-
blende schist; the dip is N. 30° W. 75°. On the state line, on a ridge
extending east from the Diamond Peaks, mica schist dips N. 85° W. 40°.
On a ridge extending to the Magalloway, south of the great bog in the
College grant, the rock is hornblende and mica schist. The dip is quite
generally W, 75°. On the Swift Diamond, in the narrows at the dam,
there is a gneissic mica schist, resting on mica and hornblende schists,
that dips N. 30° W. 62°. At the mouth of the Little Dead Diamond
mica schist dips N. 78°. This is followed on the west by a granitic
gneiss ; this is a narrow band. West of this is a band of fine-grained
gneiss, resembling the Lagen gneiss of Von Cotta, that contains fine
crystals of staurolite. This rock, as we go west, passes into a mica
schist, and in the edge of Dixville it contains an abundance of garnets.
The rock that succeeds it on the west, as far as our observations extend,
is a gray siliceous schist, which is the rock of Dixville notch. Li the
north-west corner of Dixville there is an area of gray siliceous schist,
resembling the hydro-mica schist, that dips generally S. 6S° E. 80°.
North of the Swift Diamond, two miles from Diamond Pond, a bluish
gray siliceous schist dips S. 83° E. 80°. The rock has essentially the
same dip to Dixville notch. A mile and a half north-west of the Notch
there is a small area of an argillaceous schist, very fissile and containing
pyrite, which dips S. 48° E. 75". On the old "tote "-road from the Notch
to the Swift Diamond, just north of the height of land, a gray siliceous
schist dips N. 62° W. 72°. On the ridge south of the Notch, and extend-
ing into Ervin's Location, the rock is a siliceous schist, that sometimes
contains staurolite, and on its southern border it dips south at a high
angle, and northward the dip is generally a few degrees east of south, the
strata everywhere being nearly vertical. The high ridge south of Cas-
cade brook and west of Clear stream is the same rock as that of the
Notch. The hornblende schist at the Whittemorc place has been men-
tioned; its dip below is S. 70° E. 69°.

coos AND ESSEX DISTRICT. 6l

MiLLSFIELD, WeNTWORTII's LOCATION, AND EllROL.

Between J. C. Sweet's and stream north there is quite an extensive
outcrop of chloritic schist. At the falls the rock is mica schist, but it
has been largely replaced by a coarse, intrusive granite. Near L. Lover-
ing's there is a pyritiferous schist dipping E. 74°. Near S. Rice's, on
the western border of Errol, a coarse, intrusive granite has replaced the
schist. Between Corser brook and Wentworth pond, in Wentworth's Lo-
cation, mica schist, with garnets, dips N. 70° W. 85°; half a mile north-
west of the pond mica schist dips S. 30° W. 65°; then a granitic gneiss.
East of Aker's pond the strike of the mica schist is N. 30° E., and the
strata are vertical. The schist here is full of very small garnets. The
rocks immediately south of Clear stream and the Androscoggin will be
described on Section XIL On the north border of Wentworth's Loca-
tion the rock is a mica schist, containing small crystals of staurolite, and
dips N. 82° W. 65°. At the base of the Dustin mountain, on the south-
east, the rock is a gneissic mica schist and a coarse granite. In Errol,
south of the section, in the road from Bragg's bay to Upton, Me., the
rock to the height of land is a mica schist ; and on the ridge between
the height of land in the road and the lake the strata are very much
contorted, and, where the rock presents a smooth surface, the bendings
of the strata occur on every possible scale. The general dip is S. 60° E.,
nearly vertical. South, near the town line, there is hornblende schist,
with a south-easterly dip. In Millsfield, on the section east of Millsfield
ponds, an argillaceous schist was seen. This may be an extension south-
east of the gray siliceous schist of Dixville notch. Near the height of
land south, in Millsfield, there is a hornblende schist that dips S. 80° E.
58°. South-west of Rocky pond, the most southern of the Millsfield
ponds, there is a dark siliceous schist dipping S. 65° E. 58°. A mile and
a half south-west this schist passes into a hard, dark, almost black sili-
ceous slate, which in places contains many veins of white quartz. Just
north of Newell brook there is a band of hornblende schist.

CaAIBRIDGE AND DUMMER.

On the line of Cambridge and Errol, from the Androscoggin and the
Molnichewock, the rock is a gray siliceous schist ; the dip is quite uni-

62 STRATIGRAPHICAL GEOLOGY,

formly N. 30° W. 60°. These rocks extend southward, and outcrop in
Dummer opposite T. Wentworth's, where they have a chloritic aspect;
also on the north Hne of Dummer, on the "tote "-road to Millsfield pond,
they are somewhat argillaceous. South-west of Dummer ponds there is
an extensive outcrop of gray siliceous schist, and it is quite probable that
the rock is continuous from west of the Androscoggin on the line of
Cambridge and Errol. Two miles north-east of Leighton's mill the dip
is N. 40° W. 70°. A mile and a quarter north-east the dip is S. 80° E.
80° Near G. Grapes's the dip is S. 50° E. 72°.

Stark and Milan.

At saw-mill near the mouth of Phillips brook there is a gray siliceous
schist, with vertical strata. At Stark water-station the rock approaches
novaculite, and dips S. 30° E. 72°. On the road opposite the mouth of
Phillips brook the siliceous schist dips S. 50° E. 70°. On the hill north
of Long pond the same rock dips S. 70° E. y6°. At West Milan the
siliceous schist has hornblende schist interstratified with it; the dip is
N. 50° W. 75°. In the railway cut, a mile and a half south-west of the
village, the siliceous schist dips N. 80° W. 80°. The rock here in places
is pyritiferous, and some bands contain hornblende. At Higgins's saw-
mill the siliceous schist dips N. 70° W. 75°.

Columbia and Stratford.

On the high land a mile and a half from the Connecticut, on a tract of
land formerly owned by Dr. Lombard, three fourths of a mile from the
house, in the Notch towards Sims stream, the rock is a dark siliceous
schist, that dips W. 80°. At William Gilkey's, mica schist dips N. 50°
E. 65°. The rocks of Lyman brook will be described in the sketch of
Section XII. A mile and a half north-east of Mrs. S. Day's a dark sili-
ceous schist dips W. 70°. At North Stratford the mica schist stands in
high ledges; one dip was found to be N. 58° E. 85°. But generally in
the vicinity of North Stratford the dip is exceedingly variable. Near
the mouth of Bissell brook the same rock as at North Stratford dips
N. 70° W. 80°. A mile south-east of M. D. Johnson's, and a thousand
feet above his house, a hard, dark siliceous schist comes in contact with
granite. This siliceous schist, going towards Johnson's house, has a

coos AND ESSEX DISTRICT. 63

breadth of half a mile; following this, though still siliceous, it has the
appearance of an argillaceous schist, and is very much wrinkled. This
is followed by hornblende schist. On the road, a quarter of a mile below
Johnson's, the wrinkled schist outcrops near the road, and contains stau-
rolite. The siliceous schist is exceedingly variable in its dip, but is away
from the granite. The wrinkled schist dips generally N. 60° W. 70°, and
the hornblende probably the same way. South, just below Stratford, at
B. Merriam's, the strike is east and west, and the dip is S. 80°. At the
head of Bog brook, both on the branch that comes from the Notch to-
wards Columbia, and the one from Sugar Loaf, there is a hard, dark
siliceous schist. At the south base of Sugar Loaf the dip is S. 70° E.
78°. On the road that runs south from Bog brook, from near the mouth
of East Branch, the rock is a gray siliceous schist ; near B. Brown's it
dips S. 50° E. 65°. A quarter of a mile south of the end of the road it
dips S. 70° E. 6S^. In the east part of the town, on Nash stream, there
is a similar schist, but it extends only a short distance north of Percy
I^eaks, and it dips generally S. 15° E. 65°.

Northumberland and Stark.

Extending around the south-west base of Percy peaks is a dark sili-
ceous schist, the dip of which is exceedingly variable. South of Potter's
pond a dark siliceous schist, that by weathering presents a peculiar pitted
surface, dips S. 20° E. 72°. On the east side of the Devil's Slide, and
also on the east side of Mill mountain, the siliceous schist stands vertical,
and is in contact with porphyrite, which forms the mass of these two
elevations. The same rocks are on a hill east of Groveton, and they have
the same relation. In the valley between Mt. Lyon and the Pilot moun-
tains we have the dark siliceous schist. At the east base of Mt. Lyon
the dip is S. 70° E. 72°; near the road the dip is N. 50° E. 70°. East of
the road the dip of the schist is N. 75° W. 80°, and it is penetrated by
the porphyrite.

The rocks of the Connecticut valley, from the north part of Northum-
berland to Dalton, although having for the most part the same general
characteristics, yet they are exceedingly variable, and so cut by joints
that generally it is difficult to determine the dip. In general they may
be described as chloritic feldspathic schist.

64 STRATIGRAPHICAL GEOLOGY.

In the first outcrop, about three fourths of a mile south of the north
line of Northumberland, the rock is a feldspathic quartz schist. On the
hill east there are large crystals of feldspar. At Groveton and half a
mile west we find a chloritic feldspathic schist, and interstratified with
this is a greenish siliceous schist, that dips W. 60°. On Jonathan Pond
brook, a fourth of a mile above the bridge, we find the feldspathic quartz
schist; and north, perhaps a mile from the bridge, there is a siliceous
schist that dips N. 60°; this rock in places contains a small quantity of
lime. The feldspathic chloritic schist comes in contact with the por-
phyrite on the west side of Mt. Lyon. The high hill south-east of
Northumberland falls is composed of this rock. In the south part of
Northumberland, about half a mile a little east of north from the place
formerly owned by O. S. Wood, the rock contains a large proportion of
hornblende, and with it there is a band of limestone, very siliceous, how-
ever— dip N. 60° W. 65°; a mile and a half south, on the road to Lancas-
ter, there is epidote with the chloritic feldspathic schist. On the hill east
of the Bellows farm the rock differs somewhat from the rocks elsewhere,
except in Vermont opposite, and it resembles a chloritic schist. Near the
school on Caleb branch there is a siliceous feldspathic schist ; near C.
Lee's, a chloritic feldspathic schist; near W. Savage's the rock is horn-
blendic. On the west side of Mt. Prospect the rock is a siliceous chlorite
schist — dip easterly. The rock between Lancaster village and Mt. Pros-
pect is for the most part the same, except that just above the spring that
supplies the Lancaster house there is a band of a highly siliceous lime-
stone. At S. H. Legro's the rock is decidedly feldsi^athic, and in the road,
a quarter of a mile north-east, there is an argillaceous mica schist. Mt.
Pleasant, and the ridge west, is a siliceous chlorite schist, except at the
western extremity, where it slopes towards the Connecticut, the rock is
hornblendic. At Z. and J. Dexter's the rock is siliceous and pyritiferous.
West of a small pond in the extreme south part of Lancaster the rock is
sandstone. Where the siliceous chloritic schist is cut by the railway the
rock is somewhat calcareous.

Vermont.

On the first road north of the Lancaster bridge, going west, the chlo-
ritic rock, so extensively developed in the east part of Guildhall, extends

coos AND ESSEX DISTRICT.

65

three quarters of a mile west of the Connecticut ; the dip
S. 70° W. 58°. Near Freeman's, of the county map, there :
ceous schist dipping W. 78°. Gray schist on High hill
and near C. Joy's dips N. 68° W. 65°. In road opposite
A. Benjamin's, gray siliceous schist dips N. 70° W. 80°;
half a mile west the same schist is vertical. West of
Mill brook the siliceous schist dips easterly. At Royce's
the rock is a siliceous mica schist dipping S. 70° E. 70°;
and west at a school-house a light gray siliceous schist
dips S. 50° E. 70°. South, on Mt. Tug in Lunenburg,
the gray siliceous schist dips N. 75° W. 73°. On the
road from Lunenburg to Concord there are many out-
crops of gray siliceous schist. Near the Baptist church
the dip is N. 57° W. 75°; where the road crosses Miles
stream the dip is N. yy° W. 72°; at S. Gaskill's — dip N.
80° W. 62°; on the south-west slope of High hill the
dip is E. 75°. In the last is a porphyrite, evidently pro-
duced by metamorphism from the siliceous feldspathic
schist. A mile south-west of West Concord a greenish
chloritic schist dips S. 50° E. 62°. This probably ex-
tends south to Lower Waterford.

In Fig. 7 we have on the Connecticut Huronian rocks
dipping east. On Burnside mountain we have an axis,
with slate in the synclinal. Each group of rocks to the
west probably forms inverted monoclinal axes.

MoNTAi.BAN Group.

At the south end of Umbagog lake a gneissic mica
schist dips N. 65° E. 58°. In the south-east part of
Cambridge a hornblende schist dips N. 10° W. The
rocks of this group in Success will be noticed in de-
scribing the sections that pass through the township.

SlIELBUR E.

The rocks of Shelburne are remarkably uniform.
The gneiss contains quite a large proportion of mica,
VOL. II. 9

66 STRATIGRAPHICAL GEOLOGY.

which is in well-defined plates, and it is often arranged at various angles
to the planes of stratification. On the state line between the Andros-
coggin and Wild rivers, a mile and a quarter from the former, on a high
cliff, the dip is E. 70°, On Clement brook, a mile from the road, it out-
crops, and has an easterly dip. At the lead mine it dips N. 20° W. 60°.
The other rocks are granitic gniesses, and it often occurs interstratified
with the other gneisses. There is an outcrop a mile up Clement brook ;
and there is a conspicuous area a mile west of Shelburne village, where
it has been quarried.

GORIIAM.

At Gorham village gneiss, the same as that in Shelburne, has granitic
gneiss interstratified with it, and it dips N. 60° W, 65°. The gneiss out-
crops on Mt. Hayes, but it is largely replaced by intrusive granitic veins.
The south end of the mountain ridge, south-west of the village, is granitic
gneiss, but the mass of the rock composing the ridge is andalusite schist,
that dips N, 30° W. 68°. Two miles west of the village, on the Ran-
dolph road, there is a hornblende schist that dips S. 40° E. 62°. In the
extreme north part of the town, near the Alpine cascade, the hornblende
schist dips S. 45° E. 70°.

DUMMER AND OdELL.

In the north-west part of Dummer we find an area of gneiss that has
the characteristics of that described in Shelburne ; the dip west of Dum-
mer ponds is S. 70° E. 60°. We have also in both sides of the ponds
the granitic gneiss of this group. In Odell, in the south-east corner of
the town, the dark gray gneiss dips N. 15° W. 35°. This is followed by
a granitic gneiss towards Trio ponds. The granitic gneiss also outcrops
on Nash stream, near the forks.

The Montalban in Vermont.

In the vicinity of Island Pond, and occupying at least the west side of
Bluff mountain, there is a mica schist that very closely resembles the
Montalban group, as developed in the White Mountains; the dip is S.
65° E. 70°. In Brunswick, the North and South Notch mountains are
Montalban rocks ; and in the Notch the dark gray gneiss dips westerly.
In the west part of Maidstone, on the cast shore of the lake, the charac-

coos AND ESSEX DISTRICT.

67

teristic dark gray gneiss dips N. 65° W. 62°. On Round Top hill, in
Victory, the dark gray gneiss, with conspicuous plates of mica, dips S.
35° E. 65°. In Granby, nearly half a mile north of a school-house in the
east part of the town, there is a band of gneiss that dips S. 50° E. 63°.

Other Montalban Rocks.

In the north-east part of Victory, at the forks of the road east of
Moose river, gneiss, with fibrolite, dips S. 60° W. 75°. On East Haven
mountain an argillaceous mica schist dips S. 52° E. 58°. In the east part
of Burke, at the end of a road going north from \ |
the main road, argillaceous mica schist, with \ |
staurolite in small crystals, dips S. 44° E. 60°. 1 1
On the north spur of Umpire mountain there is | ^
argillaceous mica schist, with andalusite and fib- | ^
rolite — dip exceedingly variable ; with the schist
there is granitic gneiss; in the central part of
Victory, on Bog brook, granitic gneiss outcrops.
In the north part of Kirby, in the gap between
East Burke and Kirby mountains, a mica schist,
passing into gneiss containing fibrolite, dips east-
erly. South of Kirby mountain gneiss, with fib-
rolite, dips N. 54° E. 70°. On Miles mountain,
in Concord, the rock is gneiss, with fibrolite. In
a cleared field, on the south-west side, the dip is
N. 40° W. 28°. The rock is very siliceous and is
somewhat calcareous. In the woods above the
field just mentioned the dip is N. 62° E. 55°;
top of ridge, dip N. 58° E. 70°; at the summit
of the mountain the dip is W. 80°.

Older Rocks.

The rocks of the Atlantic series here described
are probably older than the Montalban. In the
north part of Milan, on the river road, near a
school-house, the rock is gneiss. Here it con-
tains a greenish mica, and dips N. 50° W. 58°.

68 STRATIGRAPHICAL GEOLOGY.

South, at D. Evans's, the quartz forms such a prominent feature in the
gneiss that the rock has the appearance of being a conglomerate; the
dip is N. 15° W. 20°. At a saw-mill in the south-east corner of Milan,
common gneiss dips N. 70° E. 65°. East of this in Success, on the cart-
road to the meadows, and half a mile from the west line of the township,
there is a granitic rock, probably gneiss, the quartz of which is quite
friable. North on the Chickwalnepy the rock is a hornblende schist —
dip N. 30° E. 66°. On the Grand Trunk Railway, opposite Nay's pond,
there is a hornblende gneiss that contains epidote, in nodules, and veins
of calcite; the dip is N. 20° W. 50°. South, towards Milan water-station,
common gneiss dips N. 20°. At a saw-mill on Dead river, common
gneiss dips S. 30° E. 20°. North of Dead River pond there is a granitic
rock that contains a compact feldspathic rock. On Berlin heights a
pyritiferous schist dips N. 40° E. 6y°. At Berlin falls a hornblende
schist dips S. 45° E. 60°; and in a railway cut below the station there
are folds in the common gneiss, the strata being nearly vertical. There
is gneiss on Randolph mountain; and at Jefferson hill it dips N. 10° W.
18°. The same rock and nearly the same dip were observed within a
mile and a half of Lancaster village, on the road from Jefferson hill. On
the road south of Mt. Prospect the common gneiss dips N. 20° W. 18°.
South, near Blood pond, where it comes in contact with the harder Hu-
ronian rock, the dip is N. 10° W. 50°; and the strata are crumpled and
contorted. There is common gneiss on Bray's hill in Whitefield; and
in the east corner of Dalton the same rock dips N. 15° W. 18°. There
is a fine-grained gneiss west of Round pond, and it dips N. 42° W. 60°.
Southward, the common gneiss outcrops on Mann's hill in Littleton.

Intrusive Rocks, Sienite, and Porphyrite.

The most northern limit of the sienite in New Hampshire is in the
extreme southern part of Colebrook, near G. and M. Parsons's. It is
composed chiefly of feldspar and hornblende. The feldspar is of a light
flesh color, passing into a light gray. This largely predominates, the
hornblende being only a small proportion of the mass of the rock. A
few blocks have been quarried. It seems to be easily worked, and it
makes a beautiful stone. If polished it would no doubt be ornamental
for pillars, to which use some of the sienitcs and granites that contain

coos AND ESSEX DISTRICT. 69

little mica and are wrought with facility, are applied. The area of this
rock is limited, being confined to the point of land between Sims stream
and the Connecticut. In Columbia, south of Sims stream, the high
point of land that is so noticeable just before we cross that stream going
south, is composed of sienite, but it is of a very dark color, either from
its being colored with manganese, or from the decomposition of the feld-
spar. On the side towards the stream numerous boulders have been
detached, and the angular blocks lie on the steep hillside ; some of them
are so poised that apparently only a slight force is needed to send them
to the bottom of the valley. It seems quite probable that this mountain
mass south of Sims stream was once connected with Mt. Monadnock, on
the west side of the Connecticut, possibly with that north, and that the
intervening rock has been worn away. This seems more probable, since
this area of sienitic rocks, including those north and south of Sims
stream and Mt. Monadnock, are surrounded by schistose rocks. To the
south-east in Stratford we find a rock similar to that south of Sims
stream, largely developed. The summit of Sugar Loaf mountain is a
solid mass of rock two or three hundred feet in length and half as wide,
and so precipitous that there are two or three places only where it is
possible to reach the summit. Specimens of the rock from this moun-
tain can hardly be distinguished from those south of Sims stream.
South-east, but still in the town of Stratford, we come to Percy peaks.
The rock here differs somewhat from that of the localities just de-
scribed. The feldspar is more of a flesh-color, is not so abundant, and
also contains some black mica and a smaller proportion of hornblende.
It also contains quartz, and besides, what is quite uncommon, the
quartz is frequently crystallized; and, though generally distributed equally
through the mass of the rock, crystals of smoky quartz have been found
having a diameter of six inches. These peaks, so symmetrical in their
outline, with their bare, white summits, form a marked feature in the
scenery. In Stark, approaching the railway station either from the east
or west, the mountain ridges project by each other so that there seems
to be an impassable barrier. On the south is Mill mountain, and on the
north there is a precipitous mountain bluff known as the Devil's Slide.
These rocks are separated from the granitic region northward by a band
of schist. The rock of the Devil's Slide is chiefly sienite, but it is unlike

yO STRATIGRAPHICAL GEOLOGY.

that of Percy peaks or Sugar Loaf, but it resembles somewhat that at
Colebrook. The difference is chiefly in the color of the feldspar, that of
the Slide being light gray. The face of the Slide is a precipitous wall of
rock, from one to two hundred feet in height, above the debris that has
fallen down at the base of the cliff. The wall itself forms an immense
amphitheatre, — hence there is a fine opportunity for studying the rocks.
On the west, near the railway at the base of the cliff, the whole mass of
the rock is sienite; in places it is discolored, but generally it is composed
of a light-colored feldspar, of quartz that is light gray, and hornblende.
In places the hornblende is wanting, and elsewhere the rock seems to be
composed almost altogether of feldspar. This is particularly the case
towards the summit of the cliff. When we have passed two thirds of
the way around the amphitheatre, we find a schist. The strata are gene-
rally vertical, or nearly so, and they are in contact with the sienite ; in
places are penetrated by it. There is a similar arrangement of rocks on
the north-west side of Mill mountain. Towards the east side of the am-
phitheatre there are several dykes of diorite of considerable interest. It is
often amygdaloidal, and the cavities contain calcite. The heliotype shows
most prominently the west end of the Slide; and, although the whole
bluff is precipitous, near the centre of the picture can be seen the per-
pendicular wall of rock. On the extreme right is the point where the
sienite is succeeded by the schist. A close inspection will show the
Grand Trunk Railway, where it passes along at the base of the cliff.

PORPIIYRITE.*

Porphyrite is quite a common rock in northern New Hampshire. The
most northern locality where it is developed is in Stratford. East from
Connecticut river and south of Lyman brook, there is a range of moun-
tains, one of the highest points of which is known as Lightning mountain.
It can be seen from the vicinity of North Stratford, and it is the only
peak in the range that is without trees. On the south side of this moun-
tain there is quite an area where there is an exposure of a dark granitic
rock, composed chiefly of feldspar, which gives to it a greenish color;
there is also in the rock a small proportion of a dark vitreous quartz.

* Rocks classified and described by 13. Von Cotta. English edition, by P. H. Lawrence, p. i68.

coos AND ESSEX DISTRICT.

7^

On account of this rock having formerly been quarried, — for it was used
in the construction of the jDiers of the railway bridge at North Strat-
ford,— we were able to examine large detached masses, which revealed
the true character of the rock. Weathering affects this rock to a great
depth. The color of the feldspar is changed to dull gray, though it has
no decided tendency to crumble. The whole aspect of the rock is so
unlike the original, that one would hardly suspect that a rock so compact
and of such a color should be found beneath the weathered surface.

Immediately south of the Grand Trunk Railway there is a large area
that embraces several mountains of considerable height. The mountains
are known generally as the Pilot range. The highest peak is Starr Kino-,
and it is just north of the Waumbek house. Embraced in this area is
the country extending from Stark station south nearly to the Waumbek
house in Jefferson, and east from the Connecticut, from a point just
above Northumberland falls, to the head waters of the UiDper Ammo-
noosuc. Everywhere there are high mountain ridges covered with
forests, and often these ridges rise in sharp conical peaks, while in many
places there are steep slopes and precipitous walls of rock. So marked
are these ridges and mountains, that one can hardly be mistaken as to
those that are composed of porphyrite, although they are many miles
distant. There are two small areas of porphyrite on the west, that are
separated by a band of schist from the larger area eastward. Mt. Lyon,
formerly known as Cape Horn, and a hill immediately east of Groveton,
are the areas indicated. Mt. Lyon, though not so high as some of the
other peaks, yet is more noticeable, since it stands out so prominently
from the other mountains, and the valley of the Connecticut westward
makes it seem to rise abruptly from a plane. It can be seen from Mt.
Moosilauke, and from many places along the Connecticut valley. The
whole mass of the mountain is a compact feldspar porphyry; and on
the east side there is a precipitous wall of rock, from fifty to two hun-
dred feet in height, extending for nearly a mile. The jointed structure,
of the rock gives it the appearance of stratification, and the composition
is as follows:

Silica, ........... 62.2

Alumina, ........... 28.

Iron oxyd, .......... tr.

STRATIGRAPHICAL GEOLOGY.

Lime,
Soda,
Potash,

4.6

3-34

6.

On the hill east of Groveton the character of the rock is nearly the
same as that of Mt. Lyon. On the north side, however, the debris has
fallen down so that no outcrop appears until we get nearly to the top.
On the east side of this hill there is a schist, which is almost a quartzite,
that comes immediately in contact with the por-
phyrite. Between Mt. Lyon and the porphyrite
east, there is a band of schistose rocks, which
perhaps may be properly called an argillaceous
quartzite. This band forms a synclinal axis be-
tween the porphyrites. The view of Mt. Lyon,
from which the heliotype was made, was taken
at a point near Groveton, and its pointed summit
shows a characteristic of our porphyrite moun-
tains. East of the road from Groveton to Lost
Nation, and three fourths of a mile from it, the
porphyrite outcrops, and from thence to the head
waters of the Upper Ammonoosuc it appears to
be continuous. The porphyrite of this region
seems to be spread out in nearly horizontal lay-
u i^ ers. The lower portion is a dark, compact rock,
|f with few distinct crystals of feldspar, and it al-
5 I ways weathers whitish. The upper portion, which
"; .;, caps the summits of nearly all the higher peaks,
\l is a light-colored porphyrite, and the crystals of
\ I feldspar are always distinct. The only one of
£ rt the higher mountains that is not thus capped is
^ I the one that is known as South peak, a sharp,
conical mountain, that can be seen looking south from Stark station.
While the succession of rocks is so nearly the same, in so many dif-
ferent localities, it has been taken as presumptive evidence that these
rocks arc stratified ; but as there are so many places where the porphy-
rite penetrates the rocks with which it comes in contact, the intrusive
character of this rock cannot be doubted. The same reasoning in regard

3. "
X -2

coos AND ESSEX DISTRICT. 73

to the succession of rocks applies equally well to the granites in the re-
gion south of the Notch. On the north-west side of Mill mountain, half
way up, the porphyritc penetrates the dark siliceous schist, as also at the
Devil's Slide. Boulders from the Slide can be seen near Hickey's mill.
On the south-east side of Mill mountain the porphyrite comes in contact
with a schist that is similar to that which is found in contact with the
rock on the hill east of Groveton ; but here the schist is everywhere ver-
tical. As in the valley of Mill brook boulders of labradorite are common,
it is quite probable that this rock may be mostly covered up by the por-
phyrite. On the south side of the area, half a mile above the Waumbek
house and west of a small stream from the mountain, the porphyrite pen-
etrates the gneiss. The rocks that we have seen in contact with the
porphyrite are a siliceous schist almost a quartzite, a feldspathic chlo-
ritic schist, and gneiss. On the west we have the rock that is found
along the Connecticut, through Northumberland and Lancaster, which
was probably originally a sandstone, though its character as such is gen-
erally obliterated. This rock is everywhere on the west, and generally a
short distance from the porphyrite, but at the south end of Mt. Lyon it
comes in contact with it, and extends around on the south as far as Jef-
ferson. This is succeeded by a gneiss, — a rock that is extensively devel-
oped in Whitefield, — that extends through Randolph into Berlin. There
are several places where the gneiss comes in contact with the sandstone,
and underlies it. The rock on the north-east is a common granite, while
on the north there is a small area of a schistose rock, which is an argil-
laceous sandstone schist.

Granite and Granitoid Gneiss.

Rocks composed only of quartz, feldspar, and mica, and in the propor-
tions found in typical granite, are very rare in northern New Hampshire.
In the Atkinson and Gilmanton Academy grant there is a band of grani-
toid gneiss from half a mile to a mile in width, and it forms the height of
land between the Little Diamond and Magalloway. It is composed of
quartz, feldspar, and mica, both black and white, and is a rock of very
fine texture. On the west there is a narrow band of mica schist, and
this is succeeded by hydro-mica schist ; and on the east there is also a

VOL. II. lO

74 STRATIGRAPIIICAL GEOLOGY.

hydro-mica schist. The apparent dip is towards the north-west; that,
also, is the dip of the schist.' Southward, in the Dartmouth College
grant, on the Swift Diamond, and about two and a half miles west of the
Magalloway, there is a band of granitoid gneiss perhaps three fourths of
a mile wide. It is not quite so fine in texture as the last mentioned, but
otherwise it closely resembles it. On the west there is a staurolite
gneiss, which rests upon it. On the east there are mica and hornblende
schists, the strata of which are almost perpendicular, but they have evi-
dently been much distorted.

The granitoid gneiss outcrops in Wentworth's Location just west of
Wentworth pond ; and boulders of this rock, or one very similar, can be
seen along the road south of Bragg's bay. It is one of the most beauti-
ful building stones to be found in the state. In Errol, north of the road
and extending into Millsfield, a rock similar, but not so even in its texture,
can be seen. A rock in which the marks of stratification are very ob-
scure, but which in its characteristics closely resembles a granitoid gneiss,
outcrops in Dixville just at the gate of the Notch on the east. In Mills-
field, west of Millsfield pond, and in the north part of the town of Odell,
and in the central part extending nearly to Trio ponds, there are exten-
sive outcrops of granite. In the west part of Millsfield there is a high
mountain ridge of granite, rather fine in texture, the feldspar of which
is white. Westward in Odell there are three parallel granite ridges.
Here the texture of the rock is very similar to that of Millsfield, but the
feldspar is flesh-colored. West of Odell in Stratford the rock changes ;
and here we find a very coarse granite, composed mostly of feldspar and
quartz, but there is a small quantity of black mica, and there is hardly
any doubt but that this is a genuine eruptive granite, and it is newer
than the stratified rocks along the Connecticut, since in Lyman brook,
where they come in contact, it has penetrated the schists in numerous
veins and beds. On the east shore of Umbagog lake there is a kind of
granite unlike any found elsewhere in northern New Hampshire. It is a
dark gray rock, and it is composed chiefly of quartz and brownish mica.
A similar rock is found in Vermont, near Island Pond.

In Jefferson, near the Mt. Adams house, there is a granitoid gneiss
that contains a flesh-colored feldspar, light gray quartz, and minute scales
of black mica, unevenly distributed through the rock. The same kind of

. ■ coos AND ESSEX DISTRICT. 75

rock is found on Cherry mountain in Carroll, while just cast of the moun-
tain, in the south part of Jefferson, at a saw-mill, there is an exceedingly
hard granitic rock, composed of feldspar and quartz. In the south-west
corner of Randolph, at a saw-mill, there is a similar rock, very much
jointed. East of this and south of the last there are outcrops of grani-
toid gneiss. In Randolph the granitoid gneiss, composed largely of
granular quartz, extends along Moose river, nearly through the town.
At Gorham a rock like Concord granite outcrops near the village, where
it is interstratified with the White Mountain gneiss. In Shelburne there
are several extensive outcrops. Three fourths of a mile west of the vil-
lage, large C][uantities of this rock have been quarried. It appears also
south of the village, and extends a mile or more up Clement's brook. In
Martin's grant it can be seen along Peabody river, and it extends up that
stream to Mr. H. D. Copp's. It is likely to be found in many places
interstratified with the White Mountain gneiss. In Milan, three fourths
of a mile south-west of Higgins's mill, there is an outcrop of granite on
the stream that flows into the Upper Ammonoosuc, near the mill. On
the line of Milan and Kilkenny, on the mountain ridge known as Green's
cliff, there is a coarse, eruptive granite, composed of light flesh-colored
feldspar, dark gray quartz, and black mica. On the south-east side of
this ridge there is a precipitous cliff, from one hundred and fifty to two
hundred feet in height. At the base of the cliff there are boulders of
immense size, that have fallen down. One of these boulders contains
over thirteen thousand cubic yards. The granite extends probably a mile
and a half south-west from Green's cliff, and is followed by porphyrite.

In the west part of Stark, between the Upper Ammonoosuc and the
Grand Trunk Railway, there is a granite quite unlike that found else-
where in northern New Hampshire. The feldspar is of a deep flesh-
color, which gives to the rock a reddish cast. East of the high hill
where it outcrops, up the valley, there are numerous boulders of this
rock, some of which have been used in the construction of abutments to
the bridge at Stark station. It seems to be wrought with facility, and
is the only workable granite found in ledges anywhere in this section
of the state west of the water-shed between the Androscoggin and the
Connecticut.

']G STKATIGKAPIIICAL GEOLOGY.

Veins and Dykes.

Almost every one has noticed, where eruptive rocks come in con-
tact with those that are stratified, near the hne of contact, they often
send off veins into the surrounding strata. These veins do not differ
from the general mass, except that they are generally finer grained. Dr.
Hunt describes what he calls granitic veinstones, and he regards them as
concretionary. These are not, however, on the borders of great areas of
eruptive rocks. "They are," he says, "to the gneisses and mica schists,
in which they are generally inclosed, what calcite veins are to stratified
limestone; and although long known, and objects of interest from their
mineral contents, have generally been confounded with intrusive gran-
ites." The theory as to the way in which veins have been formed has
been a matter of controversy from the time of Agricola, who, in 1546,
was the first to propound a theory of veins. He supposed that the prin-
cipal agents were water, which dissolved the enclosed rock, heat, and
cold. Werner was the first to fully develop the aqueous theory. The
fissures he supposed to be caused by contraction, in consequence of dry-
ing and various other causes ; and the vein to be formed from a wet and
mostly chemical solution, which covered the region where the fissures
existed. Lasius supposed that the material was introduced in a state
of aqueous solution, as mineral water; Lehmann, that the material was
brought into the fissures by ascending steam ; Becher, that the matter
was introduced in a gaseous condition by sublimation ; Fournet, that the
material has been introduced by an igneous and purely anhydrous fluid
injection, and solidified in the fissures. Scheerer conceives the congeal-
ing granite mass to have been impregnated with a highly-heated aqueous
solution, "which, under great pressure, oozed out, penetrating even the
stratified rocks in contact with the granite, filling cavities and fissures in
the latter, and depositing therein crystals of quartz and of hornblende,
the arrangement of which shows them to have been of successive
growth."

According to Elie dc Ikaumont, the coarsely crystalline granitic veins
were injected. He supposed the material to be derived from the con-
gealing granitic mass. The veins which are characterized by a symmet-
rical banded structure he regards as concretionary. Von Cotta is in

coos AND ESSEX DISTRICT, 'J'J

doubt whether the veins which occur at Johanngeorgenstaclt arc concre-
tionary or igneous-fluid injections. "The general character of the lodes
is so like that of granite, that they might be considered to have been
injected in an igneous-fluid state; with which, however, do not agree
their slight breadth, and at times banded, even though not exactly sym-
metrical texture, as well as the irregular distribution of ores in them.
Since feldspar and mica may be formed in that way, a decision can only
be arrived at with great difficulty."*

Dr. Hunt thinks it probable that "a great proportion of quartzo-fcld-
spathic veins are of aqueous origin, and have been deposited from solu-
tions in fissures of the strata, precisely like metalliferous lodes. This
applies especially to those granitic veins which include minerals containing
the rarer elements. Among these are boron, phosphorous, fluorine, lith-
ium, rubidium, glucinum, zirconium, caesium, tin, and columbium, which
characterize the mineral species, apatite, tourmaline, lepidolite, spodu-
mene, beryl, zircon, allanite, cassiterite, columbite, and many others."!
He thinks that these elements, which are found only in minute quantities
in the mass of the sedimentary deposits, have been eliminated from the
great mass, and have been accumulated here by deposition from water.
The argillaceous, wrinkled, corrugated schist in Pittsburg, Clarksville,
and Stewartstown is remarkably free from veins, and only those of quartz
are found, but these all seem to be of one type, and rarely ever more
than three or four inches in thickness, and very rarely do they contain
any metalliferous deposits. The veins often contain peculiar longitudinal
cavities, which give to it a fossiliferous appearance. Veinstones of this
character are common between Indian and Perry streams. The veins
are more numerous in the schist containing lime than elsewhere. The
more compact portions do not, as far as we have observed, contain veins
of any kind. In the green schist, where it contains veins, the quartz has
more or less of the mineral ripidolite, a species of chlorite, associated
with it. The whetstone grit rarely contains veins. The diorite rock,
extending from Colebrook through Stewartstown, Clarksville, and Pitts-
burg to Quebec province, has in a few places veins of quartz, though
they are nowhere very numerous, and often for a long distance it has

* Von Cotta's Treatise on Ore Deposits, Prime's translation, p. 124. f Geology of Canada, p. 476.

78 STRATIGRAPHICAL GEOLOGY.

none. A place where they are the most numerous is in the vicinity of
Mud pond, in Pittsburg, and the quartz is remarkably white and vitreous.
On a hill east of J. Young's, in Stewartstown, where there are veins,
chlorite is found associated with the quartz.

At Dixville notch there are several interesting trap dykes. Near the
height of land in the Notch there are large, loose blocks, which have
come from a dyke above. The rock is basaltiform, and contains large
masses of augite and glassy feldspar, and resembles, according to Jack-
son, volcanic rocks more than any other found in the state. A similar
rock is found in the wall of Huntington cascade, south of the road below
the Notch. At the Flume, north of the road, just at the gate of the
Notch, there is a trap dyke, somewhat porphyritic, with feldspar crystals.
It is probable that, by the disintegration of this dyke, the Flume has
been formed. These dykes have cut through the schist and granite,
without apparently having disturbed or changed it.

In Millsfield, south of the road near J. C. Sweatt's, a vein a foot in width
cuts through the green chloritic schist. It is composed of feldspar, very
white, mica, nearly colorless, vitreous quartz, and occasionally crystals of
tourmaline and garnets. A fourth of a mile east of Sweatt's, at the falls
on Clear stream, is a vein four feet wide cutting the schist. Here the
feldspar is white, the quartz smoky, the mica has a greenish tinge; and,
besides garnets with a resinous lustre, there are also small crystals of
beryl. Near M. Haynes's, in Stewartstown, there is a trap dyke four
feet wide, which we were able to trace a quarter of a mile. It runs
nearly parallel to the strike of the schist.

Near the head of Blodgett brook, in Columbia, there is a dyke of trap
cutting the granitic rock. It is amygdaloidal, and contains epidote and
calcite, and, in places, distinct hornblende crystals. In the southern part
of the town, near W. Kimball's, where the granite comes in contact with
the schist, it sends off veins into the surrounding strata. These veins
are finer grained than the granite mass. This is supposed to result from
the more rapid cooling of the mineral constituents. At Groveton, on the
Grand Trunk Railway, there is a vein of hematic iron ore, which, with
the quartz, forms a kind of breccia. In Stark, in the wall of the Devil's
Slide, near the eastern extremity, there is a dyke of diorite which is un-
like any that we have seen elsewhere. It is porphyritic; and the feldspar

coos AND ESSEX DISTRICT. 79

is of a triclinic variety. At the saw-mill on Phillips brook there is a
trap dyke six feet in width.

In the vicinity of Berlin falls, veins and dykes arc very numerous.
The schistose rocks at the village, and just above, along the railway,
have been replaced by coarse granitic veins, consisting of vitreous C|uartz,
feldspar, and patches of black mica. In the railway cut just below the
station there are several trap dykes. In the second cut there is one
twenty feet wide, and it is separated from another four feet wide by a
band of gneiss a foot in width. The general direction of the dykes is
north-east and south-west. In the road just below the village there is
an extensive dyke, and at the falls below the bridge one four feet wide
extends along the river. It is porphyritic, and its direction is N. 8o°
W. Near the falls there is also a granitic vein, containing magnetic
iron ore, and it is so mingled with the rocks as to form a metalliferous
porphyry.

In Berlin, on a high bluff north of Dead River pond, there are several
veins or beds, the rock of which, though it has the appearance of jasper,
is really a compact feldspar, as a partial determination of its constituents
shows. It contains silica 69.2, alumina 19.6, lime 3, and its color is
greenish brown, striped with bands of reddish brown. The beds vary in
thickness from a few inches to several feet. At one point there is Cjuite
a cave ; its length is fourteen feet, and it is nine feet in height and six
feet wide. On the floor of the cave there is an accumulation of vegetable
mould, which contains fragments of the felsite. It has been thought by
some that this cave was excavated by the Indians, to obtain the rock for
making arrow-heads. The entrance to the cave has somewhat the ap-
pearance of having been excavated by human hands ; but, as the vein of
felsite at the entrance is not more than a foot in width, and within a
few feet of the entrance on the east there are several veins much wider,
which appear never to have been touched, that they would have removed
a large mass of granite to get this particular vein does not seem proba-
ble. The presence of fragments of felsite in the cave similar to those
found where felsite is known to have been wrought by the Indians,
makes it probable that they visited this cave, and it is possible that they
may have enlarged it somewhat ; but the origin of the cave must have
been a fissure in the rock.

So STRATIGRAPIIICAL GEOLOGY.

The Map.

The map (Plate V) that accompanies this chapter embraces the ex-
treme northern part of New Hampshire, with a small portion of the
adjacent territory on the west. Its southern limit is the beginning of
the White Mountain region. A few lines have been drawn to show the
area of the principal formations.

The larger figures show the locality where the rocks of the sections
were collected. The smaller figures show where specimens were col-
lected, to illustrate the geology of the entire area. In some places, on
account of the large number of specimens collected, the figures have
been crowded away from the exact locality where they should have been
placed. The area west of the line running through Pittsburg, Clarks-
ville, Stewartstown, Colebrook, and Columbia belongs to the Coos group.
The line southward from Columbia, nearest the Connecticut river, sepa-
rates the Huronian rocks from the sienites, granites, porphyrites, and
gneiss to the east. The latter occupy a part of Jefferson, most of Kil-
kenny, a part of Northumberland, Stark, Odell, Millsfield, Stratford,
Columbia, and a small area in Dummer, Milan, and Berlin. East of the
Coos group and this granitic area the Huronian rocks occupy most of
the remaining territory, and are conveniently divided into several groups,
one of which is separated from the rest, and is included in the lines be-
ginning at the eastern boundary, near the north-east corner of the state,
and ending in Milan. Each of these areas has been already described.

Many errors will undoubtedly be found in the map, as must necessarily
follow from the limited time given to work where so many figures are
concerned. Figure lo in Section XII should be where 9 is, and that
figure should have been put farther east; 285 in Odell should be 385;
while 42 of Section XI should be near the line of Stark and Northum-
berland.

PLATE V,

coos AND ESSEX DISTRICT.

8i

Catalogue of Specimens,*

Chiejiy from Coos County^ as arranged in the State jSIusemn at the Agri-
cultural College. Plate V, which is a photo-lithograph fro7n the
county map^ shows where each specimen %vas obtained.

77, Quartzose gneiss.

78, Fine-grained gneiss.

79, Gneiss rich in quartz.

81, Chloritic scliist, with nodules of epi-
dote.

80, Greenish schist, with gneiss interstrati-
fied.

82, 83, 90, 91, 96, 98, Chloritic schist.
86, Diorite.

117, Grayish diorite-schist.

118, Argillaceous schist.

HURONIAN GROUP.

1, 16, 38, 39, 44, 84, 85, 87, 93, 94, 99,

1x6, Arenaceous sandstone-schist.

2, 6, 8, 9, 19, 40, 64, Greenish siliceous

schist.

3, 14, 45, 97, Argillaceous mica schist.

4, 5, Serpentine.
7, Mica schist, with irregular texture and

quartz veins containing pyrite.
10, II, 12, 13, Argillaceous schist.
15, Banded arenaceous sandstone-schist.

17, Light gray siliceous schist.

18, 26, 28, Gray argillaceous mica schist.

21, Gray argillaceous slate.

22, Very fine-grained gneiss.

23, Gneissic schist.

24, Fine-grained diorite-schist.

25, 30, Light gray argillaceous schist.
27, Argillaceous sandstone.

29, 43, 65, 92, 105, 119, Gray argillaceous
schist.

31, Grayish-green diorite-schist.

32, 32, 7S, 76, Clay slate.

34, 35, Gray siliceous schist — Novaculite.
36, 89, 95, 100, Porphyritic diorite.

41, Greenish chloritic schist.

42, Argillaceous schist.

66, Quartzose mica schist.

67, Siliceous feldspathic schist.

68, Gray mottled siliceous schist.

69, Steel-gray siliceous schist.

70, Argillaceous sandstone-schist.

71, 7-7 Ji', 74. Greenish-gray siliceous
schist.

coos GROUP.

46, Arenaceous clay slate.

47, 48, 51, 53, 54, 56, 61, 62, 103, 104, 106,

107, 112, Argillaceous schist.
49, Argillaceous mica schist with pyrite.
5°» 55' 97' 109. no, III, Argillaceous mica

schist.
52, 63, Ochrey argillaceous schist.

57, 59, Ochrey argillaceous mica schist.

58, loi, 102, 113, Calciferous mica schist.
60, Argillaceous schist — wrinkled.

115, Argillaceous schist — much contorted.

coos GROUP.

120, Ochrey argillaceous schist.

121, Quartz — a veinstone.

122, Argillaceous mica schist.

123, 128, Clay slate.

124, 125, Calciferous mica schist.
127, Calciferous slate.

129, Argillaceous schist.

130, Quartz, a veinstone with sphalerite
and galenite.

* For the nomenclature we have used the reader is referred particularly to Rocks Classified and Described
B. Von Gotta, English ed., P. H. Lawrence, and the Geology 0/ Michigan, vol. ii, 1873.
VOL. II. II

82

STRATIGRAPHICAL GEOLOGY.

131, Quartz schist.

132, Argillaceous schist — ferruginous.

133, Argillaceous schist.

134, Argillaceous schist — contorted.

HURONIAN GROUP.

135, Hydro-mica schist, with magnetite.

136, 137, Hydro-mica schist.
138, 139, 148, Hydro-mica schist.
140, 141, 144, Hornblende schist.

142, 145, 149, Mica schist.

143, Mica schist, with staurolite and gar-
nets.

146, Garnetiferous mica schist.

147, Hydro-mica schist, with magnetite.

150, Mica schist, with small crystals of
staurolite.

151, Granitic gneiss.

152, Fine-grained gneiss, with staurolite.

153, Mica schist, with staurolite.

154, 155, 156, Mica schist, with garnets.
157, 158, Granitic gneiss.

160, Coarse granite.

161, Gneissic mica schist.

162, Gneiss.

163, 164, Aplite — feldspar and quartz.
165, 166, Mica schist.

167, Mica schist, fine and even in texture.

168, Granitic gneiss.

169, Granite — a veinstone.

170, Coarse granite, a veinstone with gar-
nets and beryl.

171, Chloritic schist.

174, 175, 176, 180, 181, 200, Gray siliceous
schist.

177, 179, Hydro-mica schist.

178, Dark gray siliceous slate.

182, Argillaceous siliceous mica schist.

183, 184, Argillaceous siliceous schist.
185, 186, 187, 188, "Trap."

189, Granite.

190, 191, Argillaceous schist.

192, Quartz — a veinstone.

194, 196, 198, Argillaceous mica schist.

195, Mica schist.

197, Mica schist, with staurolite.
199, Arenaceous sandstone-schist.

201, Darkgrayargillaceous siliceous schist.

202, Hornblende schist.

108, 173, Arenaceous sandstone-schist.
172, Clay slate.

COoS GROUP.

203, 206, Argillaceous mica schist.

204, Argillaceous schist — wrinkled.

205, Mica schist.

207, Diorite — intrusive.

208, Calciferous mica schist.

209, Quartz — a veinstone.

210, Argillaceous schist.

211, 216, 227, 228, 231, 232, 236, 237, 245,
246, 25 1 , Calciferous mica schist.

212, 234, 252, 261, Argillaceous schist.

217, 262, Argillaceous schist — wrinlded.
215, Clay slate.

218, 255, 257, Ochrey mica schist.
226, Arenaceous mica schist.

230, 235, 242, 253, 258, 263, Argillaceous

mica schist.
229, Argillaceous mica schist — calciferous.
233, Argillaceous schist — calciferous.
238, Quartz, with ankerite.
256, 260, Mica schist.
259, Siliceous mica schist.

HURONIAN GROUP.

213, Diorite.

214, Calcareous diorite.

219, Diorite — slaty.

222, Arenaceous sandstone-schist.

223, "Trap."

224, Fine-grained quartzose gneiss.

225, Gneissic mica schist.
221, Granite — intrusive.

coos AND ESSEX DISTRICT.

83

COoS GROUP.

241, 243, 244, 247, 24S, 250, Calciferous

mica schist.
240, Mica schist.
249, Siliceous limestone.

264, Argillaceous mica schist.
239, Protogine — intrusive.

265, Sienite.

266, 267, Limestone.

268, Mica schist with limestone.

HURONIAN GROUP.

271, Dark gray mica schist.

275, Argillaceous mica schist.

276, 277, Arenaceous mica schist.

280, 285, 287, 2S8, Mica schist.
284, Pyritiferous mica schist.
286, Chloritic schist.

278, Gneiss.

281, Fine-grained gneiss, rich in quartz.

282, Fine-grained gneiss.

272, 279, "Trap" — intrusive.

269, 270, Sienite — intrusive.

283, Granite.

385, Granite.

386, Siliceous schist.

Verniont.
289, 290, Mica schist.

291, Argillaceous mica schist.

292, Granite.

293, Fine-grained, reddish granite.

294, 295, Mica schist.

296, Contorted mica schist.

297, 298, Mica schist.

299, 301, Hornblende schist.

300, Dark gray gneiss.

302, 303, 304, 305, 306, 307, Gray siliceous
schist.

308, Gray siliceous schist.

309, Gray siliceous schist.

310, 311, Fine-grained mica schist.
312, Chloritic schist.

313, Chloritic hornblende schist.

314, Quartz.

3!5' 316, 317, 320, 322, Granitic gneiss.

318, Granite.

319. 325, 330, Hornblende schist.
321, Granular Cjuartz.

323, 326, Gneiss.

324, Siliceous slate.

327, Grayish-black quartzite.

328, Quartzite — plumbaginous.

329, Grayish-black siliceous slate.

MOXTALBAN GROUP.

331, Coarse, dark-grayish gneiss.
33-' 333' Coarse grayish gneiss.
334' 335' 337' Dark grayish gneiss.
336, 338, Granitic gneiss.
339, 340, 341, Grayish gneiss.

HURONIAN GROUP.

342, Light-gray siliceous schist.

343, 344, Gray siliceous schist.

345, Hornblende schist.

ATLANTIC SERIES.

346, 347, 349, 352, Common gneiss.
348, Protogine gneiss.

351, Hornblende schist.

HURONIAN GROUP.

353' 354' 358' 359' 362, 363. 364, 365, 366,
Gray siliceous schist.

355, Mica schist.

356, 361, 367, Hornblende schist.

357, Argillaceous mica schist, with acicu-
lar crystals of hornblende.

360, Hornblende gneiss.

368, Granitic gneiss.

369, Dark gray gneiss.

MONTALBAN GROUP.

370, 387, Fine-grained gneiss.

371, Greenish-drab siliceous schist.

372, Dark gray gneiss.

84

STRATIGRAPHICAL GEOLOGY.

373,

374, 378, 388, Granitic gneiss.

375 >

376, 379' 383' 385. Granite.

377,

Gneiss rich in quartz.

380,

38 1, 384, Light gray gneiss.

382,

Reddish granite, with dolerite.

386,

Siliceous schist.

HURONIAN GROUP.

389, Drab sihceous schist.

390, Siliceous schist.

391, 392, Bluish-gray siliceous schist — No-
vaculite.

393, Siliceous schist, with hornblende.

394, Light drab siliceous schist.

395, Siliceous schist — argillaceous.

INTRUSIVE ROCKS.

396, 397. 398, 399' 403, Sienite.

400, Felsite — a veinstone.

401, Breccia.

402, Granite.

404, "Trap."

405, Diorite.

407, 408, 409, Reddish granite.
416, Sienitic granite.

HURONIAN GROUP.

412, 413, 428, Dark gray quartz schist.

414, Trap with epidote.

415, Argillaceous sandstone.
427, Quartz.

418, Feldspathic quartzite.

419, 420, Siliceous limestone.

421, Quartzite.

422, 423, 433, 436, Siliceous schist — argil-
laceous.

424, 426, Feldspathic quartz schist.

425, Gray siliceous schist.

429, 431, 448, 451, Quartz schist.

430, Mica schist rich in quartz.

434, Argillaceous mica schist, with stauro-
lite.

435, Hornblende schist.

437, 452, 453, Argillaceous mica schist.

438, Ferruginous mica schist.

449, Fine-grained dark mica schist.

450, Fine-grained mica schist.

454, Coarse granite.

INTRUSIVE ROCKS.

432, 445, 446, Sienite.

439' 440, 441 > 442, 444' 447' Granite.

443, Aplite.

VERMONT. — HURONIAN GROUP.

455, Granitic gneiss (M).

456, Dark gray gneiss (M).
486, Sandstone — friable.

490, Mica schist.

491, Granitoid gneiss.

COtiS GROUP.

458, 468, 474, 479, Calciferous mica schist.

459, Hornblende mica schist.

460, 461, 466, Mica schist.

462, Quartzite.

463, Quartz — a veinstone.

464, Granitic gneiss.

467, Quartz with hornblende.

469, 470, 475, Argillaceous mica schist.

471, A veinstone with Vesuvianite.

472, Vesuvianite.

473, 476, Siliceous limestone.

477. Quartz.

478, Hornblende.

INTRUSIVE ROCKS.

465, 480, 483, 484, 485, 487, Granite.

481, Reddish granite.

482, "Trap."
488, 489, Sienite.

ATLANTIC SERIES.

Berlin.

492, Gray micaceous gneiss.

493, 510, 515, 516, 521, Hornblende schist.

494, Siliceous sandstone.

coos AND ESSEX DISTRICT.

85

495-
496,

497,
498,

499>
500,
SOI,

502,

503.
504,
507.
511-

512,

5i3>

514,
520,
527,

528,
529.
530,
531,
533.
542,
543.
551.
558.
566,

SZ7,
539.

548,
549.
553.
562,
567,
571.

506, Coarse granite.

Dark gray gneiss.

505, 519, 522, Gneiss.

Gneiss witli epidote.

Ouartzite.

Pyritiferous mica scliist.

Pyritiferous schist with hornblende.

iVlicaceous gneiss.

Mica schist.

Granitic gneiss.

508, 509, 526, Felsite.

523, 524, Granite.

518, Common gneiss.

Hornblende schist with veins of cal-

cite.

Coarse gneiss.

Quartz with pyrite.

"Trap."

HURONIAN GROUP.

532, Hornblende schist.

Drab siliceous schist.

535, Gneiss.

534' Sl>^^ Gray siliceous schist.

Mica schist.

Mica schist rich in quartz.

544, 545, Dark quartzite.

Dark micaceous quartzite.

Feldspathic epidotic schist.

Quartzite — argillaceous.

INTRUSIVE ROCKS.

538, Granite.

540, 541, 546, 549, 550, 552, 554, 555,

556, 557. 559. 560, 561, 562, 563. 564,

565, 568, 569, 570, 578, 579, 580, 581,

583, Porphyrite.

Breccia.

Felsite.

Labradorite.

Felsite porphyry.

Granite — a veinstone.

Schist with porphyrite.

HURONIAN GROUP.

572, 573. 577. Quartzite.

574, 612, 625, Feldspathic siliceous schist.

575, Dark feldspathic schist.

576, Feldspathic schist.

582, Feldspathic quartz-schist.

584, Dark, variegated quartz-schist.

585, Dark gray siliceous mica schist.

586, Gneiss.

587, Mica schist.

588, Chloritic feldspathic gneiss.

589, Argillaceous mica schist.

590, 593, 597, 600, Chloritic feldspathic
schist.

591, 611, 615, 616, 620, 621, 622, Chloritic
schist.

592, 617, Hornblende schist.

594, Sandstone-schist.

595, Chloritic sandstone-schist.

598, Micaceous feldsiDathic schist.

599, 601, 624, Magnesian chloritic schist.

604, Feldspathic sandstone-schist.

605, Siliceous limestone.

606, 608, Siliceous schist.

607, Greenish siliceous schist.
609, Green chloritic schist.

613, Epidosite.

614, Chloritic schist with epidosite.

618, Chloritic quartz-schist.

619, "Trap."

623, Chloritic schist.

626, Gneissic schist.

MONTALBAN GROUP.

627, 628, 629, 630, 633, 644, 671, 673,

Gneissic mica schist.
631, 632, 637, 640, 643, 646, 647, 666,

Granitic gneiss.
635, 636, Fine-grained gneiss.

638, Gneissic schist.

639, Gray gneissic schist.

641, 648, 658, 659, 660, 665, 667, Gneiss.

86

STRATIGRAPHICAL GEOLOGY.

642, 657, 669, Hornblende schist. 72)°^

645, Mica scliist. 73'^->

652, Fine-grained dark gneiss. 733'

653, 654, Light gray gneiss. 73^^

655, Gray gneiss. 737,
661, 662, Ouartzose vein. 740>
670, Siliceous schist. 752,
683, Coarse gneiss. 7S3,

INTRUSIVE ROCK.S. 754;

649, Trappean diorite. 756,

650, 651, "Trap." 757.

656, 663, 664, 668, 674, 678, Granite. 758,
672, Graphic granite. 759'
675, Granitic vein.

ATLANTIC SERIES.— M0NTALI5AN GROUP _

IN PART. ^^'
742,

700, 716, 718, Mica schist.

701, 702, 704, 706, 707, 708, 709- 712,
Coarse gneiss. 762,

703, Granitic gneiss. 763,

705, Coarse reddish gneiss. 764,

710, 711, Hornblende schist. 765,

717, 719, 722, 723, 724, Common gneiss. 766,

720, Hornblende gneiss. 769,

HURONIAN GROUP. 770,

721, Chloritic schist. 771,

725, Hornblende gneiss. 772,

726, 753, Gray argillaceous schist. 774,

727, 741, 748, 755, 760, Chloritic schist. 775,

728, 731, Quartz. 776,

729, Hornblende schist. 777,

Greenish mica schist.

734, Mica schist.

Chloritic schist and quartz.

744' 7S°, 751. Clay slate.

Slate.

745, Drab clay slate.

Chloritic quartz-schist.

Gray argillaceous schist.

Calcareous chloritic schist.

"Trap."

Chloritic sandstone-schist.

Quartz with pyrite.

Quartz with pyrite.

HELDERBERG GROUP.

747, Argillaceous sandstone.
743, 746, Argillaceous schist.

VERMONT. — HURONIAN GROUP.

Chloritic schist.

767, 768, Gray argillaceous schist.

A vein quartzose.

Gneissic schist.

Feldspathic schist.

Quartz.

773, Argillaceous schist.

Arenaceous schist.

Clay slate.

Argillaceous mica schist.

Greenish argillaceous schist.

Greenish mica schist.

Gneiss.

Sections Crossing the Coos and Essex District.

Section XIV.
Section XIV, the most northern measured, extends from a point on
the eastern boundary, three and a half miles south of Mt. Carmel, di-
rectly west, and strikes Hall's stream at the mouth of West Branch.
The country between these points is an unbroken wilderness, save where
Second lake breaks the forest, or the streams follow down the valleys.
The height at the Maine line is 2090 feet. The rock is a stratified

coos AND ESSEX DISTRICT. 87

diorite; it is of a light green color, is compact, and weathers to a light
greenish gray, and has an easterly dip. Two miles west we find a nar-
row band of clay slate; the strata are nearly perpendicular, but dip
westerly 80°. A mile west there is a dark gray siliceous schist, passing
into a light gray novaculite-schist ; this has also a westerly dip. Fol-
lowing this is a light gray siliceous schist, with an easterly dip. At
Second lake there is a compact, green chloritic schist, with a westerly
dip. Succeeding this on the west is a variety of diorite, interstratified
with which is a whetstone grit. These rocks, where they outcrop on the
section, have an easterly dip, but in other places the dip is variable. The
diorite, with the whetstone grit or arenaceous sandstone-schist, extends
three quarters of a mile west of Perry stream. Then there follows on
the west an argillaceous schist; some of the bands are hard and compact,
with an even cleavage ; but with these there arc dark bands, wrinkled
and corrugated, and both contain small cavities filled with a yellowish
brown powder, and for a little more than three miles these schists have
an easterly dip. Three fourths of a mile west of Indian stream the schist
becomes more fissile, the harder bands are less frequent, and in places
the rock is hardly distinguishable from common clay slate; but here, as
in the more wrinkled varieties, we find the same kind of cavities, only
they are sometimes larger, and from near the height of land to Hall's
stream the strata have a westerly dip: probably the easterly dip is due
to a fault. The height at Hall's stream is 1740 feet.

Section XIII.

From the Maine boundary, opposite the Academy grant, for nearly
fifteen miles, the primeval forests for the most part cover the entire
country, and the surface generally is broken by irregular mountain ridges,
and in places there are high, rocky cliffs. On the Maine boundary the
rock is a hydro-mica schist. This extends for three quarters of a mile
or more up the slope of the ridge to the west, which has an axis of gran-
itoid gneiss. On the western slope of this ridge there is a narrow band
of mica schist. This is followed by hydro-mica schist, which extends
several miles westward. Where the Dead Diamond cuts this rock it has
worn a deep gorge, and the place is known as the Narrows, and here
crystals of magnetite are quite common. The valley of the Little Dead

88 STRATIGRAPIIICAL GEOLOGY.

Diamond, from where the stream flows into the Dead Diamond, about
a mile above the Narrows, forms a deep, irregular basin towards Mt.
Pisgah and the water-shed between the Magalloway and the Connect-
icut. The hydro-mica schist forms a monoclinal axis, and has every-
where a westerly dip, though nearly vertical. In the basin of the Little
Dead Diamond the rock is sometimes quite argillaceous, but, approaching
the water-shed, it seems to pass into a gray siliceous schist. On the west
side of the water-shed, on the head waters of Cedar stream, there is a
band of clay slate perhaps a quarter of a mile in width. It has generally
an easterly dip, at a high angle. Following this is an arenaceous schist
that extends to Clarksville, but interstratified with it is a band of quart-
ziteand three bands of diorite. All these rocks have an easterly dip. In
Clarksville, also extending into Canaan, Vt., there is a series of calcareo-
argillaceous rocks, consisting of several folds. In the cast part of Clarks-
ville the rocks are both argillaceous and micaceous, and frequently they
contain lime as an incrustation. In the north part of Clarksville, particu-
larly in the vicinity of the bridge across the Connecticut, the rocks are
mainly micaceous. At Hall's stream there is a wrinkled and corrugated
argillaceous schist. This is followed by a calciferous mica schist; and
on the Connecticut river at Canaan there is a band of siliceous lime-
stone. West of Canaan village the rocks consist of micaceous schist;
probably for the most part they are calciferous mica schist. At Great
Averill pond there seems to be a granitoid gneiss; and westward, to
the first road in Holland, all the outcrops of rock are granite. Then
follows a calciferous mica schist.

Section XII.

Section XII extends from Umbagog lake directly west, and strikes the
Connecticut river half a mile north of Lyman brook in Columbia, and
extends west to a point about two miles south of East Charlestown. Be-
tween these points the country for the most part is covered by forests,
and is broken by mountain ridges and cut by deep ravines. The towns
traversed in measuring the section were Errol, Millsfield, Odell, and
Columbia, in New Hampshire, and Bloomficld, Brunswick, Ferdinand,
Brighton, and Charlestown, Vt. Umbagog lake is 1256 feet above the
sea level ; and on its eastern shore we find a dark-colored granite, pecu-

coos AND ESSEX DISTRICT. 89

liar in being composed chiefly of quartz and a dark, rusty brown mica.
In the lake there is a diatomaceous earth ; and on its western shore is a
mica schist, the strata of wdiich are nearly vertical, but generally the dip
is from 75° to 80° easterly. The hill between the lake and the Andros-
coggin is 244 feet above the former. In one specimen from the eastern
slope of this hill we noticed a trace of copper, Bragg's bay is fifty feet
lower than the lake ; and west of the bay the strata are still more nearly
perpendicular, and a mile west they dip westerly, and the mica schist here
contains garnets. Passing the height of land, and descending towards
the Millsfield ponds, on this slope we still find mica schist; but three
fourths of a mile east of the ponds there is an argillaceous schist, which
has an easterly dip, as, also, the mica schist found on either side of it.
The hills south-west of Millsfield pond are mica schist ; but the strata
seem to have been more disturbed than elsewhere on the section, as we
found that the strata dip to the south-east and south. Succeeding this
schist on the west, and forming a high mountain ridge on the border
of Millsfield, there is a granitic rock, probably a granitoid gneiss. It
is composed of a light-colored feldspar, a light gray quartz, and a small
proportion of mica.

Leaving the ridge, we descend into the valley of Phillips brook, where
there is a considerable space, nearly level, covered with drift. Passing
over the height of land west of this brook we come to the head waters
of Nash stream ; then we pass three apparently parallel ridges, all com-
posed of granite. The rock is fine-grained, of even texture, is compact,
rather tough, and it differs from the last in that the feldspar is of a light
flesh-color. Between the branches of Nash stream and Lyman brook
we find, at the height of land, a coarse granitic rock, and it is undoubt-
edly intrusive. On the western slope of this ridge there was not seen a
single outcrop of rock for a mile and a half ; but on Lyman brook, a little
more than half a mile above the last saw-mill, there is a coarse granite,
but it differs from the last in being very much jointed; sometimes the
fragments are not more than three or four inches through. Farther west
this peculiar jointed structure was not seen; but the granite is massive,
is very coarse, and is composed mostly of quartz and feldspar, but it
has also a very little black mica. West of the granite, at W. Kimball's,
the mica schist begins, and extends on the line of the section to the
VOL. II. 12

90

STRATIGKAPIIICAL GEOLOGY,

Connecticut. The strata stand at a high angle, and have an easterly
dip. Near the granite the strata are everywhere penetrated by veins of
granite; but the veinstones are of a much finer texture than the mass of
the granite.

West of the Connecticut the first outcrop is an argillaceous schist,
with an easterly dip. Where the section crosses Mill brook we have the
same rock, but west the rocks become micaceous, and the strata are
everywhere nearly vertical. Between East Branch and Yellow brook
there is a granitoid gneiss, which appears to have a westerly dip of 15°.
Between Yellow Branch and Island Pond there is the same granitic rock
that is found at Umbagog lake, and it consists chiefly of a dark gray
quartz and brownish mica. This is succeeded by a mica schist, probably
of the Montalban group, with a westerly dip.

Section XI.

Section XI passes through Success, Milan, Stark, and Northumber-
land. This section begins on the line of Maine, near the northern border
of Success. At the line the height is 1690 feet. There is, perhaps three
fourths of a mile north of where the section begins, an outcrop of horn-
blende schist ; and following the line of the section there are no outcrops
of rock for two or three miles, but there is an abundance of boulders of
the White Mountain gneiss, — so it is altogether probable that that is the
rock underlying the drift. Four miles and a half from the line of Maine,
at an old logging camp, there is a hornblende schist which has an east-
erly dip. This rock continues to outcrop for a mile; thence to the
Androscoggin there is nothing but drift, though it is probable that this
rock continues to the river. Going west from Milan Corner, the first
rock we find is a gneiss that dips nearly north, but generally N. 15° W.,
and not more than 15° or 20°. The height of Milan hill is 1460 feet.
Succeeding this on the west is a hornblende schist, probably a repetition
of that on the east of the gneiss, on which it rests unconformably. At
West Milan we find a gray siliceous schist, with bands of hornblende
schist, the strata of which are nearly vertical. Near the line of Stark
there is a slight change, and the rock becomes more siliceous. In places
the strata, as on Phillips brook, are vertical. We find, also, that they dip
both east and west, l-'ollowing the Upper Ammonoosuc these rocks

coos AND ESSEX DISTRICT. 9I

extend west to Stark water-station. At Stark station we have at the east
end of the high bhiff of rock a dark siHceous schist, probably an okler
rock than the last ; and this is followed by sienite porphyrite, portions of
which are colored by manganese, but elsewhere it is the most beautiful
rock for a building stone that we have seen in New Hampshire. Along
the river there are no outcrops of rock for two miles ; then we have a
rock, apparently an altered sandstone. On Jonathan Pond brook we have
a feldspathic quartzite ; but a short distance up the brook we have a
quartzite, probably an altered limestone, but the first mentioned rock
extends two miles west of Groveton.

Section X.

Section X extends from the Maine line, in the southern part of Suc-
cess, through Success, Berlin, Kilkenny, Jefferson, and Lancaster, and
strikes the Connecticut just north of the mouth of John's river. On the
Maine line the height is 1940 feet. The rock is White Mountain gneiss,
and here it has an easterly dip, and it extends probably two thirds of the
way across Success. It is followed by a hornblende schist, on which it
rests. This schist, with beds of granitic rock, extends to Berlin falls, at
which place it is cut by numerous trap dykes. Mt. Forist, west of Berlin
falls, is a coarse granitic rock, more like an immense veinstone than any-
thing else. While at the Falls the rock dips south-east, on the railway
below the station the rock is nearly vertical, but we have both easterly
and westerly dips. West of Mt. Forist the outcrops of rock are not very
numerous. There is a fine-grained, reddish granite east of the Upper
Ammonoosuc, and a coarser variety on the hills west.

In the valley, at the head of the branch of Israel's river that has its
rise north-east of Starr King, there are a hornblende gneiss and a fine-
grained, dark-colored gneiss. The rock of Starr King is porphyrite,
and a similar rock is found on the summits of all the peaks of the Pilot
range, except that in some instances the mass of the rock is compact
instead of being composed of distinct crystals. In Jefferson, near the
Waumbek house, we find a common gneiss. The dip of this rock, not
only on the section but elsewhere, is 10° to 20° northerly, and generally
10° to 15° west of north. This gneiss extends to Mt. Prospect, just above
the road on the east side of the mountain. The rock of Mt. Prospect,

92 STRATIGRAPHICAL GEOLOGY.

Mt. Pleasant, and the ridge west is composed mainly of quartz, though in
some places feldspar is abundant, and always a green chloritic mineral ;
and on the west slope of Mt. Orne there is also hornblende.

vSection from vSiierbrooke, p. Q;, to Connecticut Lake.

This interesting section shows the Huronian rocks on both sides of
the Coos group, as well as an island of Huronian in the latter. At Sher-
brooke the Huronian rocks consist of greenish hydro-mica schist, with
an easterly dip. At Lenoxville we have the beginning of the Coos
group, and the rocks consist of calcareous slate resting on the Huronian,
To the east the slates have intercalated bands of siliceous limestone. In
Clifton the dip is westerly, and the rocks consist of calcareous slates and
micaceous ochrey schists. Between Hall's and Indian streams the rocks
are chiefly argillaceous schists, and in general they are only slightly cal-
careous. Near Indian stream there appears to be a fault, and east of this
we find an easterly dip. From Perry stream to Connecticut lake the
Huronian rocks consist of light gray, siliceous, greenish, chloritic, and
arenaceous sandstone-schists, v/ith diorite, and the strata are everywhere
nearly vertical.

Catalogue of Sections.

Section XIV. — From the Maine Line to IlaWs Stream.

1. Diorite, state line.

2. " one fourth mile west of state line,

3. Slate, two miles west from state line.

4. 5, 6, and 7. Argillo-quartzite, two miles east of Second lake.

8. Greenish indurated schist, a mile and three fourths east of Second lake.

9. " " a mile and a quarter east of Second lake.
ID. Hard, greenish schist, a mile and a half west of Second lake.

11. Diorite.

12. Arenaceous schist, half a mile west of the head of Bog brook.

13. Diorite, three fourths of a mile east of Perry stream.

14. Arenaceous schist, half a mile west of Perry stream.

15. " " three fourths of a mile west of Perry stream.

16. Argillaceous schist, a mile and a quarter west of Perry stream.

17. Argillo-mica schist, three miles cast of Indian stream.

18. Argillaceous schist, wrinkled and contorted, a mile and a half east of Indian

stream.

19. Argillaceous schist, fissile, near last.

coos AND ESSEX DISTRICT. 93

20. Argillaceous schist, wrinkled, three quarters of a mile east of Indian stream.

21. Argillaceous mica schist, somewhat calcareous, half a mile east of Indian stream.

22. Wrinkled micaceous schist, half a mile west of Indian stream.

23. Iron-ore breccia, a boulder near the last.

24. Argillaceous schist, wrinkled and spotted.

25. " " " a mile west of Indian stream.

26. " " " a mile and an eighth west of same.

27. " " a mile and a half west of Indian stream.

28. " " spotted and fissile, two and a quarter miles west of Indian

stream.

29. " " wrinkled, near 28.

30. " " wrinkled and spotted. [This and the two following are not

far from three quarters of a mile from Indian stream.]

31. " " with quartz veins.

32. " " spotted, near Hall's stream.

Section XIII. — I^rom the east part of Holland .^ Vt., to the JMalnc Boiui-
dary^ opposite the Academy Grant.

1. Hydro-mica schist, formerly called "talcose," Maine boundary.

2. Granitoid gneiss, a mile and a quarter west of Maine boundary, and forming the

axis of the mountain ridge east of the Dead Diamond.

3. Mica schist, two miles from Maine boundary ; contains hornblende.

4. Hydro-mica schist, with crystals of magnetite, the Narrows, Dead Diamond.

5. " " argillaceous, a mile west of the Dead Diamond.

6. " " " about two miles west of the Dead Diamond.

7. Indurated schist, a mile east of water-shed, Connecticut and Magalloway.

8. " '• argillaceous and ferruginous, following 7.

9. " " argillaceous and micaceous, half a mile east of water-shed.

10. Compact, indurated schist, quartzose, calcareous, and ferruginous, water-shed.

11. Clay slate, three quarters of a mile west of water-shed.

12. Argillaceous mica schist, with decomposing mineral.

13. Diorite, about a mile west of water-shed. This is interstratified with an arenaceous

schist.

14. Arenaceous schist, two and a half miles west of water-shed.

15. Diorite, Clarksville.

16. 17, 18. Arenaceous schist, Clarksville.

19. Diorite, Clarksville.

20. Argillaceous schist, Clarksville.

21. Argillaceous schist, calciferous, Clarksville.

22. " " " "

23. Calciferous schist, Clarksville.
24.

94 STRATIGRAPHICAL GEOLOGY.

25. Diorite, intrusive, Clarksville.

26. Siliceous limestone, "

27. Decomposing schist, calciferous, Clarksville.

28. Siliceous limestone, Clarksville.

29. Decomposing limestone, Clarksville.

30. Quartz vein, Clarksville.

3i> 32. 33- Argillaceous schist, Clarksville^

34. Mica schist, Clarksville.

35. Argillaceous mica schist, Clarksville.

36. " schist, Stewartstown.

37. " schist with ferruginous spots, Pittsburg.

38. Mica schist, north-east part of Canaan.

39. Siliceous limestone, north-east part of Canaan.

40. Arenaceous schist, " "

41. Adamsite schist, " "

42. Mica schist, one mile south-west of Canaan village.

43. Veins of quartz in 42.

44. Mica schist, Canaan.

45. " " a mile and a half from Connecticut river.

46. Argillaceous mica schist, Canaan.

47. " arenaceous schist, about six miles west of Connecticut river in Canaan.

48. Mica schist, Canam.

49. " " begins to dip west, Canaan.

50. Argillaceous mica schist, Canaan.

51. 52, S3, 54, 55- Mica schist and quartzite, Canaan.

56. Staurolite schist (loose), Canaan.

57. Mica schist (mica black and abundant), Canaan.

58. " " Averill.

59. Granitic gneiss, boundary of Averill and Norton.

60. " " a mile west of Great Averill pond.

61. Granite, half a mile east of Grand Trunk Railway, Norton.

62. 63, 64. Granite, two miles west of Grand Trunk Railway, Norton.

65. Granite, boundary of Norton and Holland.

66, 67, 68, 69. Granite, Holland.

Section XII. — From East Charlestoxun^ Vt., to Umbagog Lahe.

Mica schist, cupriferous, Errol.
" " a mile and a half west of Umbagog lake, Errol.
" " Bragg's bay.

" " one fourth of a mile west of Bragg's bay.
" " with garnets, half a mile west of Bragg's bay.

coos AND ESSEX GROUP. 95

6. Mica schist, a mile and a half west of Bragg's bay.

7. Argillaceous schist, east part of Millsfield.

8. Hornblende schist, " "

9. Mica schist, one fourth of a mile west of Millsfield pond.

10. Granitoid gneiss, near west line of Millsfield.

11. " " Odell.

12. " "

13. " " west part of Odell.

14. " " east part of Stratford.
15.

16. Schist, quartzose, " "

17. Granite, mountain, head of Lyman brook, Stratford.

18. " near " " "

19. " a mile above saw-mill, Lyman brook.

20. " near W. Kimball's (west), Stratford.

21. " veins, with mica schist, near W. KimbalPs.

22. Mica schist with granite, near W. Kimball's.

23. " " " " " " (east).

24. " " one mile east of Connecticut river.

25. " " three fourths of a mile east of Connecticut river.

26. " " half a mile east of Connecticut river.

27. " " one fourth of a mile west of Connecticut river, Bloomfield.

28. Argillaceous schist, slaty, half a mile west of Connecticut river, Bloomfield.

29-

30. Mica schist, three fourths of a mile west of Connecticut river, Bloomfield.

31. " " two miles west of Connecticut river, Bloomfield.

32. "

33. " " near M. Fuller's, Bloomfield.

34. " " between Fuller's and East Branch.

3S- "

36. " " East Branch.

37. Gneiss, one mile west of East Branch.

38. " three fourths of a mile west of Black brook.

39. Granite (with a triclinic feldspar), between Yellow and North branches.

40. " near Grand Trunk Railway, Ferdinand.

41. *' near Island pond, Brighton.

Section XL — From Groveton to the Maine Boiindary^ near north line of

Success.

1 . Mica schist, boundary, north line of Success.

2. Hornblende schist, half a mile west of line of Maine.

3. White Mountain gneiss, a mile and a quarter west of line of Maine.

96 STRATI GRAPHICAL GEOLOGY.

4. White Mountain gneiss, a mile and three eighths west of line of Maine.

5. Schist, chloritic, three miles west of line of Maine.

6. Hornblende schist, three and one eighth miles west of line of Maine.
7-

8. Mica schist, three and three eighths miles west of line of Maine.

9. Hornblende schist, three and a half miles west of line of Maine.

10. Gneiss, three quarters of a mile west of line of Maine.

11. Hornblende schist, F. Bennett's, Milan.

12. Gneiss, G. Russell's, Milan.

13. " B. Flint's, "

14. Hornblende schist, near W. Fogg's, Milan.

13. Mica schist (quartzose), cut, G. T. R., three fourths of a mile south-cast of West

Milan.

14. Argillaceous schist (quartzose), same as 13.

15. Schist (argillaceous, with hornblende), same as 13.

16. Argillaceous quartzite, same as 13.

17. " " with hornblende, same as 13.
18.

19-

20. " mica schist, same as 13.

21. " schist with hornblende, near school, West Milan.

22. " " West Milan.
23.

24. Hornblende schist, "

25. Argillaceous schist, •'
26.

27. Hornblende schist, "

28. Argillaceous schist, "

29. " quartzite, three fourths of a mile west of Dummer.

30. Hornblende schist, " " " "

31. Argillaceous mica schist, " " " "

32. " quartzite, railway crossing west of Dummer.

33. " " Phillips brook. Stark.

34. " " road opposite Phillips brook. Stark.

35. " " Phillips brook. Stark.

36. " " L. Potter's, Stark.

37. " " Stark water-station.

38. " " (a dyke). Devil's Slide, Stark.

39. "Trap" (a dyke). Devil's Slide, Stark.

40. Sienite, Devil's Slide, Stark.

41. " with micaceous quartzite, Devil's Slide, Stark.

42. Sandstone, three fourths of a mile west of S. Cole's, Stark.

coos AND ESSEX DISTRICT. 9/

43. Ouartzite, Jonathan Pond brook, Northumberland.

44. " micaceous, same as 43.

45. Iron-ore breccia, Groveton.

46. Greenish quartzite, Groveton.

47. Chloritic feldspathic schist, Groveton.

48. Ouartzite, Groveton.

49' 5°' 51- Chloritic feldspathic schist, Groveton.

Section X. — From Cojuzccticnt River at South Lancaster to the JSIainc
Boundary^ near line oj" Success.

I. White Mountain gneiss, Success.

3. Mica schist. Success.

4. Gneiss, Berlin falls.
5.

6. "Trap,"

7. Coarse granite, one fourth mile west of Berlin falls.

9. " " half a mile west of Berlin falls.

10. "Trap," Mt. Forist.

11. Gneiss, near Wheeler's mill, Berlin.

12. " half a mile above Wheeler's mill, Berlin.

13. Fine-grained reddish granite, west part of Berlin.

14. " gneiss, Berlin.

15. Hornblende, near line of Kilkenny.

16. Fine-grained dark gneiss, "

17. Porphyrite, summit of Mt. Starr King.

18. Gneiss, Jefferson hill.

19. " Jefferson.

20. " "

21. Gneiss, east side of Mt. Prospect, Lancaster.

22. Chloritic sandstone-schist, north of Mt. Prospect, Lancaster.

23. " " west slope of Mt. Prospect, Lancaster.

24. " " east " " "

25. " " Mt. Pleasant, Lancaster.

26. " " ridge west of Mt. Pleasant, Lancaster.

27. " " Martin Meadow hills, Lancaster.

28. " " Mt. Orne, Lancaster.

29. Diorite schist, west slope of " "

30-

VOL. II. 13

CHAPTER III.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT.

IWIHE outlines of the White Mountain district have been defined in
J^ Volume I, page 184. It includes the principal mountainous region
between the Connecticut river and the Maine line, embracing the larg-
est areas of the Labrador granites. A reference to the description of
the topographical features, as above cited, but more particularly to the
map opposite page 171, will serve to fix in the mind the exact limits of
the district now under consideration. The leading formations developed
here are the following, in the supposed order of their age: i, Porphyritic
gneiss; 2, Bethlehem gneiss; 3, Berlin or Lake gneiss; 4, Montalban
group; 5, Franconia breccia; 6, Labrador system or Pemigewasset series
of granites, Ossipytes, compact feldspars, etc.; 7, Sienite; 8, Andalusite
slates ; 9, Pequawket or Mt. Mote granite. The facts relating to surface
geology and the utilization of valuable ores and building materials belong
to subsequent chapters.

I. Porphyritic Gneiss or Granite.

This rock is always readily recognizable in this district by the pres-
ence of large crystals of orthoclase or potash-feldspar scattered through
a base of much finer materials. These larger crystals are usually about
three quarters of an inch in length, rarely two inches. There is much
diversity in respect to their arrangement. Sometimes the crystals are
placed in the rock with their longer axes parallel to each other, and this

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 99

plane is coincident with that of the strata. On the contrary, there is
often no arrangement to correspond with the stratification. Owing to
scanty exposures, and to the abundant accumulations of decayed rock,
earth, and vegetable mould, it is often difficult to determine to which of
the two varieties of arrangement referred to above each example belongs.
It is obvious that one of these rocks must be a granite, and the other
gneiss. In our explorations no distinction has been made between them.
The assumption has been that the agencies producing the granite oper-
ated with greater intensity, so as to induce a pasty condition in the mass,
and obliterate the stratification without destroying the porphyritic aspect
of the rock. If the difference in condition involves radical distinctions
in the mode of origin or in the time of the fusion, then there are two
formations to be considered instead of one. But in that event the sec-
ond rock was derived from the first, so that the assignment of both to
one group at present will not lead to error in respect to the geographical
areas occupied by the porphyritic rock.

The mica in this rock is supposed to be muscovite. It is usually black,
or of a very dark brown color. Quartz is scarce, varying with the local-
ity, and it is always amorjahous. Iron is so abundant that most of the
exposures are stained by its oxidation. The texture of the rock is rather
coarse, the crystalline particles averaging from one sixteenth to one
eighth of an inch in length.

This formation is disposed along two converging lines in the White
Mountain district. The first extends from about the line of Carroll and
Franconia along the westerly base of the Franconia mountains into Ben-
ton, spreading out broadly in Lincoln and Woodstock east of Moosilauke,
and sending a spur from Bald mountain in Franconia into the valley of
the Pemigewasset, certainly as far as Walker's falls. This is the main
range, and it seems to terminate in Campton and Rumney. The second
area extends northerly from Ashland and Holderness to Waterville, being
a part of a range largely developed in the Merrimack district. Beyond
Waterville it may be said to bifurcate, part appearing in the valley of
Sawyer's river in Elkins's grant, and part taking an easterly course
beneath Mt. Whiteface into Conway.

The tvestcrn range. Plate VI, Fig. 7, shows the relations of the west-
ern range of this rock in Franconia to the adjacent formations, as well as

lOO STRATIGRAPHICAL GEOLOGY.

to the outlier of porphyritic gneiss near Wing Road station. There seems
to be an antichnal axis on the west flank of Mt. Lafayette, and hence
the two areas may be connected by a syncHnal beneath the Bethlehem
gneiss in Franconia and Bethlehem. The following are the facts sug-
gesting the existence of the anticlinal. We have no observations of the
dip north of the outlet of Echo lake. On Bald mountain, a hill north-
west from Echo lake, the dip is from fifty to sixty degrees north-westerly,
verging northerly. The rock is coarse; the porphyritic crystals are
larger than is common; the mica is black; and the inclination was ob-
served very satisfactorily. Dykes of trap cut across the hill. The cliffs
on the north and east sides of Echo lake are composed of porphyritic
gneiss dipping about 50° N. 32° W. It is supposed that this rock is
continuous to the Lake of the Clouds, north of Eagle cliff, but, on ac-
count of the difficult travelling, the actual connection has not been traced
out. The ragged cliffs between the Echo and Cloud lakes are conceived
to belong to the Franconia breccia, which is an igneous overflow consist-
ing of large fragments torn off from the porphyritic rock, and embedded
in a feldspathic paste. At the Lake of the Clouds no doubt exists as to
the occurrence of the porphyritic gneiss ; and I have the impression that
the feldspar crystals lie in horizontal planes, but I cannot be absolutely
certain of it. I have noted that the rock makes its appearance half-way
between the crest of Eagle cliff, where the new path crosses it, and the
lakes, and that the strike may be N. 28° E. both east and west of these
small tarns. Physically sj^eaking, there is a broad shelf where this water
is situated, which is more than four thousand feet above the sea, from
whence water flows northerly and southerly. Following the old bridle-
path from the Cloud lakes to the south, the porphyritic gneiss crops out
about one third of the way down, with a dip of fifty degrees easterly.
To the east of the lakes towards Lafayette a finer-grained gneiss suc-
ceeds, which may correspond to one of the overlying formations. I think
the dip is easterly in this case. There seem to be outcrops of this rock,
also, on the cast side of the mountain underneath the Lakes of the
Clouds. Thus, although the facts observed respecting the dips are
meagre, the easterly and westerly inclinations are clearly known to exist
in the proper place to constitute the anticlinal ridge represented upon
Plate VL

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 01

It is not necessary to particularize the few localities to the north-east
where this formation appears, save that it has not been traced beyond
the east line of Franconia. One of our maps will show the exact loca-
tion of every specimen mentioned in the catalogue ; and reference to
these sources of information will render unnecessary much detail in the
text. An interesting locality lies above Walker's Staircase in the edge of
Lincoln, which is supposed to be the direct continuation of the easterly-
dipping ledges just described. Coming down from the south end of the
Lafayette range towards the Staircase, I found, about a mile back from
the road, nearly horizontal masses of a hornblende rock, underlaid by
porphyritic gneiss, running N. 2° W., and having nearly vertical strata.
The hornblende rock formed a succession of steps, over which the brook
fell in a picturesque way, while the porphyritic gneiss did not rise above
the base of the cascade. I cannot locate this spot exactly, since I failed
to find it in 1873 in the ascent above the Staircase frequented by the
summer visitors. About the same distance back from the carriage-road,
however, I have noted the occurrence of the porphyritic rock having the
same inclination. At the "Lappara falls," also, just above Apron falls,
considerably higher than the Staircase, Mr. Huntington found a gneiss
resembling the porphyritic rock, save in the absence of large crystals of
feldspar, while at the latter locality the gneiss is Montalban in appear-
ance. The other rocks here are of the Conway granite series.

A specimen of loose Bethlehem gneiss from near Mt. Pemigewasset,
just back of the Flume house in Lincoln, led to a reexamination of that
eminence in 1873, and the conclusion was reached that the lower part of
the mountain consisted of porphyritic gneiss, dipping gently north-west-
erly, capped by the Conway granite, the two resembling each other
very closely. It is ajDparently a part of the more eastern range on the
west flank of Lafayette.

Further researches in Franconia and Lincoln are desirable in order to
determine satisfactorily the limits of the porphyritic gneiss. There is no
part of the White Mountains where the travelling is more difficult than
here, — hence a considerable time will be required to make satisfactory
examinations. Areas requiring a visit arc the district referred to this
group, extending from Walker's Staircase into the east part of Franconia,
and as far on the north flank of Mts. Haystack and Twin as discoveries
will warrant.

102 STRATIGRAPHICAL GEOLOGY.

The next locality where this rock has been observed as the continua-
tion of the Bald Mountain locality is on the northern peak of Mt. Kins-
man, An unknown space of about three miles between them has not
been traversed at all by any of our parties, but is supposed to be occupied
by the same formation. The strata on the Kinsman ridge, a mile north
of the summit, dip 50° N. 20° W., and, at a cascade low down the west
side, near its western border, they incline 50° N. 32° W. The rock has
also been observed by our parties upon the summit of Mt. Kinsman. To
the south of Kinsman the formation must contract in width, perhaps
passing beneath the northern point of Woodstock, and expanding in the
central part of Woodstock wider than is known elsewhere in this range.
At the mouth of Moosilauke brook at North Woodstock the dip is 70° S.
37° E. A quarter of a mile farther north the position is essentially the
same. Upon Section VIII several specimens of this formation have
been collected, proving its occurrence to the west line of Woodstock,
and it probably dips beneath Moosilauke to come up again in Benton
on the other side of the andalusite mica schist. The outcrops along
the section, in connection with a limited area in Wentworth (Specimen
No. 121 1), constitute all the evidence we have in regard to the existence
of a narrow range of this porphyritic rock west of the main range, unless
it be in Sullivan county, much farther south. Along the west side of
the Pemigewasset valley in Woodstock the porphyritic gneiss constitutes
high, bald cliffs. At the post office or central village the dip is 85° S.
57° E. Half a mile east of Elbow pond a rough gneiss, much contorted,
dips about 80° S. 32° E. South of J. Downing's in Woodstock a coarse
gneiss dips very high S. ^y° E. There is a similar rock dipping 75° N.
37° W. at the outlet of Hubbard pond, thus indicating the presence of an
anticlinal axis in the south part of Woodstock. In Thornton this rock
appears south of Hatch hill, near R. Tompkinson's, also at a saw-mill a
quarter of a mile to the south, and at J. Oilman's, where it is traversed
by veins of very coarse granite. Many other exposures occur along the
valley through Thornton, crossing the river so as to connect with the
most southern ledge known of this sort in the very edge of Campton.
Our observations in this valley were mostly made before we understood
the true character of the rock. Being regarded as granite, no pains were
then taken to observe lines of stratification in it which doubtless exist.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 03

The relations of the group to the adjacent Montalban schists, in a sec-
tion from West Thornton to Welch mountain, are shown in a figure
farther on.

From Woodstock centre the porphyritic gneiss branches off south-
westerly into Ellsworth and Rumney. That occurring in Ellsworth will
be described under Section VII. In the north-east part of Rumney, at
a lead mine, the dip is 80° N. 72° W. To the south this range is entirely
covered by the mica schists of a much later geological age.

TJie eastern range. The northern extremity of a very crooked range
of porphyritic gneiss enters the limits of the White Mountain from the
north-east corner of the Merrimack district, continuing for ten miles,
where it is concealed by later formations. It reappears in the deep valley
of Sawyer's river, about five miles north-easterly from Cascade brook in
Waterville, which is the extreme northern limit of this range in New
Hampshire. A spur runs easterly from this range along the south line
of Waterville towards Chocorua.

Section VIII crosses the Sawyer's River outcrop of this rock. The
most satisfactory exposure is represented by numbers 58 and 59, from
the mouth of Carrigain brook. The water falls twenty-five or thirty feet
over the smooth ledges of this rock, which seems to dip 75° N. 68° E.,
cut by a six-feet dyke of reddish feldspathic rock. These exposures
show large crystals of a somewhat flesh-colored orthoclase in greater
abundance than usual ; and there are many small bunches of amorphous,
nearly transparent quartz. The rock rings when struck by the hammer.
The width of the range must be two miles along this valley. This rock
comes up next on Cascade brook in Waterville. The cascades are of
granite ; but about half a mile above them the porphyritic gneiss appears,
with a northerly dip, but the strata are greatly contorted. At two miles
above the cascades the dip is 75° N. 80° E. This exposure shows amor-
phous quartz like that on Sawyer's river. None of the other specimens
from Waterville have this mineral present. Those from near the cas-
cades and the summit of Black mountain do not display the large crystals
of feldspar. We have no observations respecting the dips of this rock as
it is exposed just east of the Greeley hotel, the top of Snow's mountain,
Flat Mountain pond, the country between the last two mentioned locali-
ties, nor of the large areas of this rock on the western side of Black

I04 STRATIGRAPIIICAL GEOLOGY.

mountain. The formation is five miles wide as it enters the White
Mountain district from the south, or along the route of Section VII.
Israel and Sandwich mountains in Sandwich are composed of this rock.
Guinea hill appears to contain a different rock, jutting into the eastern
edge of the porphyritic gneiss, so that the course of the range is irregular.

Two sets of exposures farther east indicate the extension of a spur
easterly from Waterville along the base of the mountain range of Black,
Whiteface, and Chocorua. A little west of the usual path up Mt. White-
face this rock crops out, dipping 25° N. Perhaps the lower eighteen
hundred feet of the mountain, in ascending from McCrillis's house, should
be regarded as composed of this formation. The top rock is of sienitic
character. Little is known of the mountains between Whiteface and
Chocorua, so that the extent of the porphyritic rock easterly has not
been observed, but, as it constitutes the basis of everything in this part
of the country, it may turn up almost anywhere. Near the south-east
corner of Albany I found enormous boulders of this rock, enough to
make it clear that the ledge must be close by. A very small area is
therefore thus represented upon the map.

Forty specimens illustrate these various areas in the museum, as indi-
cated by the catalogue. All rocks found within the porphyritic areas are
grouped together in the enumeration, although the igneous dykes are
evidently of later origin. It is probable that other bands of stratified
rock should be included, as will be developed by further study. The
typical field for the study of the porphyritic gneiss is the Merrimack
district.

Bethlehem Gneiss.

In 1 87 1 it became evident that between Carroll and Littleton there
existed an area of gneiss distinguished from all others by its peculiar
stratigraphical position and lithological character. The strike seemed to
run nearly east and west ; the strata stood almost upon their edges ; the
schistose character had nearly disappeared, so that we had previously
known the rock as granite ; and, lastly, a soft, greenish mineral, resem-
bling one of the hydro-micas, was disseminated through it. Hence I
ventured to separate this area from all the others then known, and gave
it the name of Bethlehem gneiss, from the town where it displayed itself

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 105

to the best aclv^antage.* Later observations, while modifying certain
features of the geographical distribution, and adding new areas to the
map, have tended to confirm this original impression.

Inasmuch as the typical area of the Bethlehem gneiss lies partly in
three different topographical districts, though principally in the one now
under discussion, I have thought it best to describe it entirely in this
place. It occupies portions of the towns of Carroll, Whitefield, Beth-
lehem, Franconia, Littleton, and Lisbon. The specimens, however, arc
grouped geographically in the White Mountain and Ammonoosuc, as
well as the Coos and Essex, special collections. The references will be
made to them clearly enough to avoid confusion.

The most characteristic of the rocks composing this formation is a
reddish granitic gneiss, the flesh-colored orthoclase predominating, with
chloritic or some hydro-micaceous mineral in place of ordinary mica, and
amorphous quartz in variable proportions. When this is not present it is
not easy to say that the finer-grained gneiss associated with it necessa-
rily belongs to this geological horizon. This second variety is like the
finer gneisses of the Montalban group. A third variety is a porphyritic
gneiss, sometimes suggesting the older group just described. It differs
from that in having smaller crystals of feldspar, which are arranged in
nodular bunches in the midst of the finer micaceous layers of the rock.
This variety is abundant in Carroll and the west part of Bethlehem, as
well as in the Hanover area of gneiss. A fourth variety of rock, which
may well be associated with the Bethlehem group, is a feldspathic mica
schist having large patches of a black mica, the mineral not existing as
plates exhibiting easy cleavage, but being an aggregation of crystalline
fibres. Other rocks of a foreign character are beds of chloritic schist,
with or without magnetite, nearly compact feldspars, quartz, mica, horn-
blende, and epidotic schists, and probably beds of limestone.

The following are observations of the position of the strata in the
several parts of the terrane.

Locality — Bet]ilehem . Dip.

North of M. Phillips's, 60° N. 22° W.

East of Peaked hill, N. 22° W.

South-east side of Round mountain, .... Strike N. 48° E.

* See Report for 1871 ; also vol. i, p. 33.
VOL. IL 14

io6

STRATIGRAPHICAL GEOLOGY.

Location — Bet 111 die at .
Top of Peaked hill,
East side of West Peaked hill,
Top of the same, .
Near C. C. Clarke's,
West of Baptist church, on hillside
Top of same hill, .
East of T. Twombly's, .
E. B. Phillips's, west corner of tow
C. Pe trie's, ....
P. G. Russel's, north line,
Franconia road, west part of tow

Littleton.
East side of Eustis hill,
Near Scythe Factory Village,
S. M. near Lisbon line,

Whitefield.
North of M. Bowles's, .
East of G. W. Rowland's,
Westof J. W. Walker's,
Kimball hill, top and south side,
East of J. Lindsey's,
Town-farm to N. E. Hutchins's,

Franconia.
G. W. Smith's, north corner,
R. Wallace's,
W. Wallace's,
J. McDonald's,

Carroll.
Hill north of Twin Mountain house,

Dip.

75° N. 32° W.
75° N. 62° W.
67° N. 42° W.
80° N. 32° W.
75° N. 10" W\
80° N. 20° W.
70° N. 27° W.
55° N. it W.
80° N. 40° W.
80° N. 48° E.
70° N. 27° W.

75° north-westerly.

Vertical, strike N. 58° E.

. Northerly about 30°.

75° N. 62° W.

20° West.

West.

65° N. 67° W.

55° N. 8° E.
20° easterly.

80° N. 27° W.

5o°-6o° S. 10° W.

Strike N. 53° E.

. 80° N. it W.

60° south.

An inspection of these positions shows a general inclination to the
west of north. In the north corner of Franconia there is a local anti-
clinal. At the Twin Mountain house the rock dips southerly ; and there
is a distinct antichnal in Whitefield. The best interpretation of the
structure seems to be that of an inverted synclinal in Bethlehem (see
PL VI, Fig. 7), and an anticlinal in the spur extending northerly. The
north-east part of Bethlehem and large parts of Carroll and Whitefield
are so much covered by drift that we cannot make out the structure of
this formation in a very important locality. It is easier to regard the
porphyritic gneiss of Franconia and the Wing Road region as connected

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 10/

beneath the Bethlehem formation than as newer rocks, partly because the
Whiteficlcl branch is overlaid closely by the Berlin or Lake gneiss upon
both flanks, without any room for the first-named group. Moreover, the
south-west end at North Lisbon is flanked by newer rocks, which follow
around the point, although the dip is reversed upon the north-west side,
Helderberg strata apparently running under the Bethlehem gneiss. As
this is plainly an overturn at North Lisbon, it is probable that the mono-
clinal dip farther north may be explained in the same way.

The most characteristic localities of the chloritic gneiss occur in Beth-
lehem, between Pierce's bridge and the Baptist church, or Nos. ^6 to %6
of Section IX. Round mountain appears to be one great ledge. Peaked
hill shows plenty of ledges high up, the lower portions being generally
covered by drift. In all the western part of Bethlehem the ledges occur
chiefly on the elevated points of the hills. No ledge has yet been dis-
covered upon the large Beech hill in the north-east part of the town.
Neither has any solid rock been found on the Ammonoosuc between the
Wing Road station and the falls just below the White Mountain house,
save a very obscure outcrop of Lake gneiss east of Mr. W. H. Bean's.
The large, loose blocks scattered over Bethlehem hill are mostly of this
rock, and will be noticed again, when speaking of a local glacier which
once overspread this part of the country. In Franconia every drift hill
is crowded with them.

Between Bethlehem station or Pierce's bridge and Gale river there is
no direct pubHc road, although the elevation is not great, and the dis-
tance to be traversed is only two miles. The stages between the Profile
and Crawford houses use instead the circuitous and sometimes dangerous
road over Bethlehem hill. But in the absence of carriage-roads we have
traversed the area on foot, and find the ledges entirely concealed by
glacial drift. The same is essentially true of the area between the high-
est saw-mill on Gale river and the house of S. Bullock, at the end of a
road leading south from the east and west road, a mile and a half towards
the station from the Bethlehem post-office. A supposed ledge north of
Bullock's shows a strike of N. 48° E., while to the south is the end of a
large moraine pointing towards Mt. Washington. This road to Bullock's
is situated upon the top of coarse moraine-like materials, and lies near
their eastern edge.

I08 STKATIGRAPIIICAL GEOLOGY.

The Bethlehem group probably extends north-easterly to the neighbor-
hood of the Pond of Safety in Randolph. The following numbers of the
catalogue in Chapter II appear to belong to this series: 665, on Randolph
mountain; G^^j, a mile north of the Pond of Safety — both in Randolph; —
the following in the south-east part of Jefferson: 683, near the Mt, Adams
house; 685, S. P. Martin's; 686, B. F. Read's. Also, 684, from Owl's
Head in Carroll, near the Jefferson line. In Whitcfield, Nos. 701-709, 712,
719, and 722 seem to be of this age. Very likely 710 and 711, which are
hornblende schist, may be varieties of this formation. The northerly
boundary of the formation in Whitcfield would seem to extend from the
south-eastern part, past J. Lindsey's, south of the village to near M.
Bowles's. It then extends southerly, crossing the Bethlehem line about
a mile north of the Wing road. Near the south line of the town upon
the eastern road the features of the typical rock are as distinct as in
Bethlehem. On Kimball's hill the layers nearly touch some of the Coos
mica schists. Farther north they come in contact with the Lake or
common gneiss. Epidotic and hornblendic masses are contained in the
Whitcfield area of this formation. Near J. Lindsey's the rock contains
hornblende and molybdenite. Near A. D. Sanborn's there is also molyb-
denite in a quartz vein.

Carroll has not been thoroughly explored. In the north-west portion,
near C. E. King's, a great many loose fragments, which must be in place
close by, belong to the spotted variety of this formation, corresponding
thus to the ledges near the Twin Mountain house. The country between
these localities, about five miles in extent, is covered by drift and bor-
dered much by forests, so that much knowledge of the ledges is imprac-
ticable. Cherry mountain affords us specimens of this formation, though
nothing is known of the position of the strata there. I think there are
several ledges upon the east side of Beech hill in Carroll, which remain
to be examined.

In the valley or west part of Franconia all the ledges are concealed by
drift. Back of J. McDonald's, on the flank of Mt. Haystack, the gneiss is
less characteristic than usual, and there are interstratified with it seams
of hydro-mica schist, containing magnetite (46, 47) and nearly compact
feldspars. The Bethlehem rock is exposed also higher up the mountain,
about a mile west of Haystack pond, and also on the peak next the cone

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. lOQ

of Haystack on the ridge towards Mt. Lafayette. Other locaUties to the
south, whence specimens have been brought by our student assistants,
who did not determine the position, are, — first, a problematical spot be-
tween Mts. Pemigewasset and Kinsman (50); second, on the south-west
side of the Mt. Flume ridge, near its foot and just across the valley from
Little Coolidge mountain (51); third, on Big Coolidge mountain, three
miles north-easterly from Pollard's, or the last house up the East Branch
valley in Lincoln (52); fourth, south of Mr. Pollard's, at the south-east
extremity of the ridge south-east of Black mountain. Such of these
locations as seem certain will be found represented upon the general
geological map.

Nos. 87-95 of Section IX represent what we call the upper member
of the Bethlehem group, consisting of dark mica schists, with some
gneiss. Its occurrence in other terranes besides that of Bethlehem in-
dicates its importance as a stratigraphical member of the gneissic series.
I associate it with the Bethlehem rather than with the Lake group for
the present, because it is so closely connected with the Bethlehem and
Hanover islands of gneiss, but it is very difficult to separate it from the
gneiss of Littleton. In Bethlehem and Lisbon this dark schist envelops
the south-west extremity of the range, as if it were another protecting
envelope. In certain railroad cuts east of Littleton this member is dis-
tinctly gneissic, some of the layers being identical with fragments of rock
found in Franconia by Prof. J. D. Dana, and thought by him to be very
like certain Laurentian rocks in eastern New York (No. IX — 95). In
the Ammonoosuc collection this member is represented by Nos. 8, 9,
17-22. No. 58 comes from a locality not far south of the Lisbon-Little-
ton road-crossing of the Ammonoosuc river, near J. Little's house, and it
agrees perfectly with this band of rock, and may be a small island of this
schist surrounded by the Lisbon group of the Huronian.

At the east foot of Eustis hill, and on the Ammonoosuc river at the
south line of Littleton, the gneiss is spotted. The same is true of speci-
mens in the west part of Bethlehem, upon Section IX. The inversion of
the strata at North Lisbon, so as to bring the Helderberg rocks upon
both sides, causing newer beds to dip beneath older ones, is illustrated in
one of the figures elucidating the structure of the Silurian rocks, in the
next chapter. At W. Wallace's in Franconia the gneiss abounds in red

no STRATIGRAPIIICAL GEOLOGY.

feldspar, and shows more than the average amount of quartz. Near the
top of the hill, near the town line, there is a mass of soft chloritic schist
ten feet thick imbedded in the gneiss. On the very top of the hill there
are many micaceous seams interstratified with the ordinary rock. This
is the area where a local anticlinal exists.

In the White Mountain collection this formation is represented by
Nos. 41 to 54, and 176 and 177, from the height of land in the road
between the White Mountain house and Jefferson. By the study of
these, in connection with those specified in the Ammonoosuc collection,
the Coos and Essex district, and along the route of Section IX, and
comparing the locations upon the maps with their dips, one can learn
all that it is possible now to present upon the subject.

Topographically, this northern terrane of Bethlehem gneiss is one
continuous central ridge, normally the most elevated along the central
median line. A ridge commences at the union of the "South Branch"
with the Ammonoosuc at North Lisbon. From 66"] feet at the railroad it
rises immediately to 1000 feet in the hill west of Streeter pond. Falling
off a few feet, it attains to 1329 feet on the height of land in the stage-
road between Franconia and Littleton ; then it rises to form four summits
in Bethlehem of 1600, 1600, 1905, and 2042 feet, the last being Peaked
hill. Next in our eastward course we find the valley of the Ammonoosuc,
1200 feet, which, on account of long-continued atmospheric grinding and
gouging, has excavated a notch through the ridge. On the east is Beech
hill, 1800 feet, a gap of 1475 back of the Twin Mountain house, and
then the final rise to 3670 feet in Cherry mountain. The excavation of
Israel's river in Jefferson, beyond Cherry, where the range is very nar-
row, brings the level down to 1250 feet before we finally lose the forma-
tion near the Pond of Safety at 2000 feet. The Bethlehem ridge is quite a
conspicuous one, when viewed either from Mt. Cherry or Mt. Washington ;
and the wide valleys of Franconia and Israel's river are subordinate to
the main line of elevation. The Whitefield spur is also quite elevated,
rising considerably above the 1500-feet contour line in the south part of
the town, while the looo-feet level scarcely touches it south of the vil-
lage, and none of the area in Jefferson goes below 1200 feet.

Fig. 1 1 will show the relations of the Bethlehem and Lake groups of
gneiss between Dalton and Carroll. We present the dips of the strata

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I I I

only where they have been observed ; and the spaces where nothing has
been discovered are given upon a correct scale. From this figure one
gets the impression that the first named is the oldest group. The section
should be compared with that on Plate VI, to which reference has been
made at the outset. Fig. ii shows the only locality in the state where
the Bethlehem and Lake gneisses are known, at the present moment of
writing, to approach each other so closely.

To this series I have referred a narrow band of gneiss, extending from
the unnamed peak (5) in front of Mt. Hale (vol. I, p. 198) through the
south part of Carroll into Franconia. The rock is a fine-grained gneiss,
similar to that in the north part of Whitefield and Littleton. The ridge
just spoken of is the first hill seen south of the Twin Mountain house,
forming the dividing ridge between the Ammonoosuc and its tributary,
called Little river. It slopes gradually from mountain (5) to the mouth of
the tributary, one or two miles below the hotel. At a dam, more than
half a mile above the mouth of Little river, the gneiss dips 35° S. 27° E.
The north wall here is high and steep, as if the stream flowed through a
canon. There is a minor undulation half a mile higher, the dip being ten
degrees northerly. On top of the ridge, in passing directly from the
hotel to Twin mountain, the gneiss dips 50° southerly. About a mile
above the junction of Little river with the Twin Mountain branch, a
small slide has uncovered ledges of this rock, rather conglomeratic in
character, dipping 80° S. T]° E. A quarter of a mile higher up, the ex-
treme easterly point of this band is reached, standing vertically, with the
strike N. 20° E. The width of this band is not known to exceed half a
mile at any point.

Proceeding from Little river towards Franconia, it is supposed that
this band must lie in front of the "Nubble." This hill rises sharply more
than three hundred feet, and was found to consist of an enormous vein of
very coarse granite. The specimens brought from it remind one of the
coarse veins yielding mica in Grafton ; but no certain evidence has been
obtained to show that the Nubble belongs to this set of strata. Speci-
mens from back of J. L. Rine's in Franconia appear to belong to this
range ; also, those lying between the porphyritic gneiss and Albany

112 STRATIGRAPIIICAL GEOLOGY.

granite, above the Lakes of the Clouds, upon the west side of Lafayette.
The connection between this and the larger area of Lake gneiss in
Landaff has not been made out, on account of the enormous coating
of drift concealing the strata west of the porphyritic gneiss. In the
museum, Nos. 315-320 illustrate these rocks. I should add that there
is a ledge of this gneiss between Bethlehem hollow and the Wing Road
junction, with strata dipping 80° N. 42° W. It belongs properly to
another field of description, the Ammonoosuc district.

4. The Moxtalban Group.

The limits of this formation have been set forth with sufficient exact-
ness in Vol. I, pp. 522-526, so as to render a repetition of the general
statements there made unnecessary in this place. The characteristic
rock of this formation is a feldspathic mica schist, carrying crystals of
andalusite or some closely related silicate. The variations are from mica
schist and quartzite on the one extreme, to well characterized gneiss on
the other. These schists are commonly quite ferruginous. The mica
occurs in small blotches, shining from light reflected at various angles.
The ledges of this variety commonly decompose readily.

A not less important variety is a granitic gneiss, with very different
degrees of crystalline coarseness. The finer-grained rock often displays
no visible marks of stratification, though there is no reason to doubt its
sedimentary origin, and, for convenience, this is designated the Concord
granite. This rock is usually incoherent, tender, and quite friable after
decomposition has commenced. It is distinguished from the Lake gran-
itic gneiss by its fineness of texture.

Along Mt. Washington river the gneiss contains many small nodules
of feldspar, so as to resemble the porphyritic variety of the Bethlehem
group. In Jackson there are a bed of siliceous limestone and layers of
compact feldspar. The eruptive members are quite important, consisting
of trap dykes, considerable masses of a porphyritic granite, light-colored
diorite, sienite, and large veins of quartz. The different ledges of this
rock among the White Mountains are well represented in the museum.

Geographically, this formation may be divided into the main range of
the White Mountains east of the Saco river; the country to the east of

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. II3

this elevated axis, south of the Androscoggin river and east of the Pea-
body and Ellis rivers ; a few small outliers near the Saco river ; and the
outcrops to the west of the Saco in "Pcmigcwasset." We will speak of
each of these geographical areas in turn.

The main WJnte Moiuitain range. The location of this elevated dis-
trict has been noted in the chapter upon Topography, page 187. The
first elevation, known as Pine hill or Camel's Rump, is composed of three
kinds of rock, — an approach to the andalusite newer slates at the north
end, a fine mica schist near the top, on the west side and on the east, and
on the southern sloj^e the Concord variety of granite. A similar rock
occurs on the Pinkham Notch road, on the height of land between the
Glen house and Randolph. The strata are nearly vertical, with a north-
erly strike. About Wood's hotel, where the Pinkham Notch road crosses
Moose river, the rock is coarse mica schist; and there are large boulders
of quartzite, various granites, hornblende schist, and sienite. South of
Bowman's old tavern-stand, near the ridge dividing the Moose and
Israel's rivers, there are both hornblende schists and fine-grained quart-
zite. A hundred rods south the characteristic fine and coarse-grained
mica schists make their appearance.

The higher peaks, — Mts. Madison, Adams, and Jefferson, — are chiefly
composed of the coarse mica schists, with a little feldspar, that are most
typical of this group of strata. In ascending Madison, from the summit
on the Pinkham Notch road, we observe chiefly an interstratification of
these schists with granitic gneisses. The strata stand nearly upon their
edges, and the non-feldspathic beds preponderate. At the upper line of
trees the mica schists exist alone, with the dip 85° S. 63° W. The rest
of the way to the summit is over fragments broken off the ledges by the
action of frost. At the very top the rock contains large garnets and
andalusite, with the dip 60° S. 58^ W. From the summit to the end of
the spur running southerly towards the Half-way house, on the carriage-
road up Mt. Washington, nearly two miles, the ledges are finely exposed,
the whole distance lying above trees, and the dips are very variable. A
short distance south of the summit the dip is 60" N, 57° W., which may
represent the normal position, but the rest of the way they incline north-
erly, westerly, easterly, and north-easterly. Two or three of these varia-
tions may occur in the distance of one hundred feet. The conclusion to
VOL. II. 15

114 STRATIGRAPinCAL GEOLOGY.

be derived from these facts is, that a powerful pressure has been exerted
upon these strata, which has doubled and twisted all the layers in detail,
not in the mass like the representations of the Appalachian curvatures
by the Professors Rogers. Observations upon Adams, Jefferson, and
Washington show the same thing to be true there also, so that this con-
clusion will apply equally forcibly to the whole range. The extent of the
reduplications exceeds anything that I have ever seen in any part of the
world.

In descending from this ridge to H. D, Copp's house, in Martin's
Grant, the most noticeable feature is the introduction of large crystals
of staurolite into the rock. Andalusite had been abundant all the way
from the summit of Madison ; but at about three hundred feet below the
tree line, in an open space, the staurolite has striped the ledges in every
direction. The crystals run up to eighteen inches in length; and I
think there is scarcely any place in the state where large and showy
specimens of this mineral can be obtained more easily, only that they
cannot be conveniently transported. It is unusual to find this mineral so
abundant among the mountains. Lower down, the crystals are smaller
and very distinct, the strata dipping 75° W., and very shortly falling to
an average of 28°, continuing thus for a great distance. About three
fourths of a mile above Copp's the same staurolite rock dips 50° S.
53° W. The granitic gneiss makes its appearance a little below Copp's.

The general surface features of the path up the north side of Mt.
Adams, and the route from Madison to Washington over the ridge, are
set forth under the head of Scenographical Geology, Vol. I, p. 613, ct
scq. Mt. Adams has three summits instead of two, as heretofore stated.
The more southern one is properly the Ouincy Adams, and there is also
a small peak between the central peak and the Madison notch. The
summit of Adams is very sharp, there being only one small block of
stone at the apex. Ridges extend down the north side of the mountain,
starting from the two lesser peaks. None of our parties have traversed
the north side of Adams, Madison, or Jefferson, so that we cannot de-
scribe the ledges there. On the summits and in the notches between
them the rock is invariably the feldspathic andalusite mica schist, with
the blotchy mica. On Ouincy Adams the strata dip N. 20° W. Near
the Jefferson- Adams notch the dip is 50° east. Still farther south the
dip is N. 62'' W.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. II5

Messrs. Channing and Hale, assistants of Dr. Jackson, ascended Mt.
Jefferson from the north, and make the following statements respecting
the ledges encountered by them:* "We travelled up the bed of the
stream [Israel's river], and observed that the rocks exposed to view were
ledges of granite, becoming coarser as we proceeded, and containing
small plates of mica not more than an inch square. Loose masses of
hornstone or jasper were observed among the pebbles in the stream."
"No [large plates of] mica were found, but an abundance of fibrolite or
fibrous kyanite occurs on Mt. Jefferson and Mt. Washington."

The following rocks were found in a trip from Mt. Jefferson summit
directly to Ammonoosuc station, following down the ridge north of that
on which the railway is located: First, the common White Mountain
mica schist ; second, the same, extending as low as to the upper limit of
trees; third, granitic, like the Concord variety, within the upper forest;
fourth, quite a number of ledges of the mica schist; fifth, jointed granite,
the third ledge above the station ; sixth. Concord granites ; seventh, a
mixture of the two kinds of rock at Ammonoosuc. Specimens illustrat-
ing these varieties are embraced in Nos. 191-200.

Upon Jefferson and Adams there are occasional large veins of white
quartz, whose course can be traced among the fragments very clearly, on
account of the contrast in color between this and the prevaihng variety.
Upon Mt. Clay the strata are better defined than is generally apparent
upon these summits, the rock approaching an argillaceous schist. They
are usually nearly vertical, and much thrown about, as described upon
Mt. Madison.

Peabody River valley. At Gorham the rock is a coarse, massive gran-
itic gneiss, dipping 65° N. 72° W. back of the old Alpine house. It
continues up the Peabody valley for two miles or more, passing into the
Concord variety. This occurs, interstratified with the mica schist, nearly
as far as Copp's house in Martin's Grant, dipping five degrees north-west-
erly. Very near by is a mica schist dipping 65° N. 72° W., which is more
like the normal position in this neighborhood. Mica schists and granitic
gneisses occur between Copp's and the Glen house, and the latter in-
crease in going towards the height of land southwardly. Upon the west

* Final ReJ>ort , Geology of New Hatiipshire , by C. T. Jackson, p. 159.

Il6 STRATIGRAPIIICAL GEOLOGY.

branch of the Peabody river, one of the most important gulfs on this
range, the rocks are mainly mica schists (Nos. 201-205), ?igreeing closely
with those found upon the presidential summits, and they all dip west-
erly, except one easterly, opposite the Half-way house. A ledge at the
mouth of this tributary is considerably ferruginous, with shining mica,
not in plates, nearly vertical. It is noticeable that none of the newer
andalusite slate, such as occurs so abundantly upon the lower half of the
carriage-road, was perceived in this great gulf, though there may be a
little of it at the mouth of the valley. The ledges near the Glen house,
and also by J. Bellows's, have the dip of 30° N. 58° W.

Section tJirongJi Lit. Washington. This is properly a part of Section
IX, and the numbers referred to are those of specimens arranged on
Shelf IX in the museum. Special surveys of the Fabyan turnpike and
carriage-road having been made under our direction, I have had them
reduced so as to be represented upon Plate VII, with all the detail pos-
sible respecting the stratigraphical and geographical position of the speci-
mens collected. The positions of the mile-posts on the carriage road are
given with great exactness. Those of the specimens taken from inter-
mediate points are located by estimate.

Directly back of the toll-gate is a ledge of greenish, somewhat friable
quartzite (No. 10). This and related ledges higher up dip 30° to 40° N.
83° W. At about three fourths of a mile there is a face of gneissic rock
exposed, 200 feet long and 40 feet wide, upon which glacial striae are
obscurely indicated. The mica in No. 1 1 is different in physical aspect
from that common to this region. The scales are narrow and much
elongated, instead of being roughly roundish. Interesting brecciated
dykes are represented by No. 12. These dykes are quite frequent on
their eastern slope, and are particularly noticeable at Crystal falls. At
the first mile-post the strata are also gneissic, with granitic veins dipping
30° N. 63° W. After passing about an eighth of a mile of drift there is
a massive quartzite. No. 13 is an argillo-mica schist, with undulating,
shining surface, and roundish, ferruginous spots of some decomposed
mineral. A small hill on the north-east side of the road is composed of
coarse granite (No. 14), containing large crystals of black tourmaline. It
is followed by ferruginous schist (No. 15) dipping 40° N. 23° W. Another
mass of granite is represented by No. 16. Between Nos. 14 and 15 there

J7

MoA/TALBAN Group, 10-12; 36-62.
Andalusite Mica Schist, X3-3S.

%

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. II 7

is a small stream running southerly. The next rock (No. 17) is slaty,
dipi^ing N. 43° W. Underneath a clayey rock is a sandstone (No. 18),
dipping 50° N. 28° W. No. 19 represents a conglomerate trap, cutting
the strata, probably, as it is inclined 85° N. 43° W. No. 20 is from a
mass of coarse indigenous granite. No. 21 is a slate dipping 20° N. 43°
E. It is interstratificd with beds of granite, fifteen to twenty feet thick ;
No. 22, a little farther along, dipping twelve degrees in the same direc-
tion. There is a sharp angle in the road here; and minute undulations
in the strata are observable, the first of them being much steeper than
the rest, or 30*^-40° N. 83° W. The rocks are mica schist, six feet thick-
ness of granite, a slaty curve over ten feet of granite, and compact quart-
zite. No. 24 dips 75° N. 63° W. A little higher up two rock masses
join each other, through an interesting fault, the positions being 80° west
and 25° N. 38° W. At the second mile-post a massive andalusite rock
dips 50° N. 58° W. (No. 25). There is a small hill just beyond, at a sharp
bend in the road. No. 26 dips 60° N. 43° W. No. 27 changes abruptly
to 25° N. ^8° E. at the next bend in the road. The rock is shaly and
twisted. Above a long northerly stretch in the road the strata are partly
fine sandstones, dipping 30° N. 38° W. No. 28 is rather more slaty, a
very fine exposure dipping 30° N. 38° W. This is just below a long
bridge over a stream flowing north-easterly. On the upper side of the
bridge there is a considerable banded granite (No. 29), in beds two feet
thick, dijDping 35° N. 38° W, The adjacent schist displays minute cor-
rugations, reminding one of ripple-marks in sedimentary sandstones.
Not a great distance higher up there are other thin beds of granite, con-
taining large crystals of black tourmaline. The strata are wavy for a
considerable distance, and then plunge into the mountain vertically, the
steep dip being the first part seen in the ascent.

Nos. 30 to 35 are taken from a series of ledges about three quarters
of a mile in length, most clearly exposed by the recent removal of earth
and by blasting. The rock is an argillo-mica schist, quite evenly bedded,
well filled with crystals of andalusite, and of the ordinary slate color.
The small curvatures in them are endless, and almost baffle all attempts
at description. They resemble billows in the ocean, each three or four
feet high, and the positions of their crests and hollows are easily deter-
mined. There is one special feature among them of importance, viz.,

Il8 STRATIGRAPIIICAL GEOLOGY.

that, after a succession of them for forty, fifty, a hundred feet, or more
are noted, their lower side disappears by plunging vertically into the
mountain, and another series of curves, with the vertical or westward
dip, takes their place. There are few places in New Hampshire where
these curious phenomena of curves can be observed to better advantage
than along this carriage-road.

At No. 30 the dip is 30° N. 12° E., vertical just below. At No. 31,
close by the third mile-post and an easterly-flowing stream, the average
dip is 35°-40° N. 27° E. The axes of the small curves here run N. 30°
W., or transversely across their dip, showing that the smaller curves
have been made since the determination of the position of the great
mass of the formation. On the upper side of the long bridge over the
stream at No. 32 the dip is 50° N. 12° E., and the eastern portion of the
ledge is turning very much southerly. In the next fifty feet of linear
distance there are three folds. Above them the dip is 80° S. 87° W. ;
thirty feet above the dip is 80° N. Zf E. ; thirty feet farther the dip is
50° S. 87° W. This continues for one hundred feet. Here is a vertical
plunge into the mountain, the strata dipping gently in an easterly direc-
tion just beyond. Near by the dip is 65° easterly. The last of these
ledges that is exposed is midway from the third mile-post to the Half-
way house, with the dip 80° S. 87° W. (No. 35). For about a third of a
mile the road passes over drift, and no exposures of ledges occur imme-
diately along the path.

This building is very near the upper limit of trees; and atmospheric
agencies have acted powerfully upon the ledges, weathering them very
much, so that they resemble the Montalban schists upon the surface.
Excavations near the house show massive beds of mica schist dipping
50° N. 23° W. At the fourth mile-post, or the most northerly point on
the road, and looking across a deep gulf to the south spur from Mt. Mad-
ison, the dip is N. 63° W. (No. 37). At a sharp turn beyond (No. 38) the
dip is 25° N. 23° W. At No. 39 the dips are 60° easterly and perpen-
dicular. At four and a half miles from the toll-gate the average dip is
60° easterly. At No. 40 there is an interesting complexity of folding.
The normal dip of the strata is S. 23° E., followed by a dip in the direc-
tion 25° N. 23° W., the other part of a synclinal axis. The southern part
of this synclinal basin, or that inclined northerly, is itself folded, the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. II9

subordinate curve dipping N. 8y° E. This feature is like that ah'eady
mentioned in the rock near No. 30.

At the fifth mile-post, where the road reaches its most southern limit,
there are more undulations in the strata, of which perhaps the average
inclination may be estimated as 15° N. 87° E. That their appearance
may be properly understood, the reader is referred to the two annexed
heliotypes taken of ledges at or very near the fifth mile-post. The bends
are perhaps zigzags rather than curves, but they represent the character-
istic forms of these phenomena in this portion of the section. This is
the andalusite mica schist of the Montalban series, which commenced a
short distance above the limit of trees, and continues to the summit as
well as to Ammonoosuc on the west side of the mountain. A few rods
above the fifth mile-post the dip varies from 75° to 90° N. Sy° E. (No.
43). F^ifty rods farther the dip is 75° in the same direction. No. 44, at
nearly five and a half miles, comes from strata dipping 50°-6o° N. 73°
W. No. 46 comes from a sharp angle in the road overlooking the Great
gulf, where the dip is 55° S. 33° E., on a ledge one hundred and fifty feet
long. A rocky knob rises on the south side of the road, just at the lower
edge of a sedgy plat, on which the dip is 25°-40° S. 23° E. (No. 47).. Ten
rods north of mile-post No. 7 the dip is 55° S. 87° W. (No. 48). At the
mile-post the dip is 50° westerly; and in certain granitic veins the feld-
spar is abundant. On a hummock near the summit the dip is 20° N. 48°
W. Standing east of the hotel, on the summit, one sees a hill to the
right of the road, above the head waters of the Ellis river, where the
strata apparently dip about 60° easterly. On the very summit the dip is
25° north-westerly. Just behind the Tip-top house the dip is S. 23° E.
On a spur towards the Lakes of the Clouds the dip is 60° S. 47° W.
Thus there is considerable variation in the dip at the very summit, a
.small synclinal eighty feet long showing itself at the highest part of the
mountain. The rocks are coarse and fine feldspathic mica schists, with
andalusite, beds of granite containing tourmaline, and veins of white
vitreous quartz. One specimen shows staurolite.

On the west side, follov^ing down the railway, less pains have been
taken in observations of the positions, and the ledges are few. The dip
is thought to be essentially like that on the summit all the way to Jacob's
Ladder. A short distance below the Ladder, in a railway cut, the rock

I20 STRATIGRAPIIICAL GEOLOGY.

is full of andalusite, and dips 60° S. 62° W. At the first tank (from
below) a number of loose pieces of a mica schist, holding delicate crystals
of staurolite, are abundant, and they were at first supposed to represent
the ledge, but nothing of the kind has yet been discovered in place.
At the station the strata are mica schist, granitic layers, and andalu-
site beds, dipping 60° to 70° N. 38° W. This is the last ledge of the
schists observed in this neighborhood, though the granites which suc-
ceed seem to have been erupted through crevices in them.

It should be distinctly understood that Nos. 10, 13-36 are regarded as
belonging to a much newer system than the Montalban, though they are
described above without special limitation.

jE//is river above Pinkhain notch. After leaving the granitic gneisses
cropping out south of the Glen house, and we begin to ascend the valley
of Ellis river from the height of land in the road, we find a compound of
quartz and feldspar, granitic in appearance. Next we come to the Crystal
falls, where the base formation is a fine-grained variety of the Montalban
schists, traversed by enormous dykes of trappean character. The dip is
6Z° westerly. Half a mile higher the coarser mica schists crop out, with
an easterly dip. Ledges are scarce, however, in this valley ; and in Tuck-
erman's ravine the inclination is westerly again. The dip is very steep
low down, but only 28° above the snow-bank. High up the side of the
ravine, towards the summit of the mountain, the dip is in the direction
of N. 83° W. The ledges are finely developed near the snow-arch ; and
the westerly dip into the mountain may be distinctly apprehended in the
photographs of the "Thousand streams," and also in "Raymond's cata-
ract," on the easterly-flowing stream in the next ravine to the north. Dr.
J. W. Dawson speaks of the "gneiss" he observed in the depths of Tuck-
crman's ravine, in his paper on Alpine plants. The absence of the newer
series of rocks is as marked along the Ellis as in the west branch of the
Peabody river.

SoittJi of Mi. WasJniigton. Trips to the south of Mt. Washington, in
several directions, afford a few observations. Upon the Davis bridle-path
the rock is uniformly the coarser feldspathic mica schist, with occasional
small, clearly-cut crystals of staurolite, in addition to the usual sparse
sprinkling of andalusite. On the cast side of Oakcs's gulf, before the
path descends much, the dip is from i4°-20° N. 43° W. Four and a

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 121

half miles north of the mouth of Mt. Washington river the dip is S.
67"" \V.

Passing from the summit hotels to the Lakes of the Clouds, one walks
over immense piles of angular fragments separated from the ledges by
intense refrigeration. The north-westerly dips near the point of depart-
ure have been mentioned. On a hummock north of the lakes the dip is
5° S. To the south of the lakes the rock is a slaty micaceous quartzite.
Beyond it is schistose again, dipping 75° westerly. The westerly dip of
the whole mass of Mt. Monroe is distinctly observable from Mt. Wash-
ington. The Crawford bridle-path passes around the east side of Monroe ;
and the schists grow gradually more feldspathic and granitic, so much so
that I called them all granite on my first trip over this road in 1858.
There are great veins of feldspar associated with them. On the east side
of Mt. Franklin there is a slide. Coarsely grained gneisses and mica
schists make up the summit of this mountain, dipping 10° west.

A trip down the west side of Mt. Franklin, July 16, 1870, will always
be remembered by the party of young men who went v/ith me at that
time. We had walked from the "Twin River farm" to the summit of Mt.
Washington, and thence past the Lakes of the Clouds to Mt. Franklin,
and were exceedingly wearied. The side of the mountain appeared
smooth, and we anticipated a pleasant trip back again to our camp.
But the beautiful greensward turned itself into an inextricable labyrinth
of the short, stiff growth of subalpine evergreens for an interminable
distance, and the camp was not reached till quite late in the evening.
The last part of the way was through chopped trees which had not been
cleared off, and in the pitchy darkness proving to be a more serious
obstacle than the scrubby growth of the subalpine region. On reaching
the brook between Mts. Pleasant and Franklin the rock was found to
be quite ferruginous, but the same granitic gneiss with that on the sum-
mit of Franklin. It contains veins of coarse granite, showing a few
crystals of feldspar three inches long. This is followed by a width of
half to three fourths of a mile of clear, beautiful granite, showing nearly
horizontal jointed seams running through it, though their position is not
uniform. This is followed by a porphyritic variety of granite.

In the gap between Mts. Franklin and Pleasant the usual schists of
this range dip N. 88° W. Mt. Pleasant is always known in scenic views
VOL. n. 16

122 STRATIGRAPHICAL GEOLOGV.

by its dome-shaped summit. [See heliotype, Vol. I, p. 220.] The top is
well covered by drift, not of great thickness, nor sufficient to prevent the
acquisition of information about the rocks, which are granitic and coarse
mica schists, with ferruginous admixtures. Dykes of trap occasionally
occur all along the range, one in which numerous jointed seams divide
the rock into small pieces. On the south side of iVIt. Pleasant, as well as
upon Mt. Franklin, there are numerous large concretion-like bunches, two
or three feet across, in the common schists. The layers in these bunches
usually have a different position from that of the adjoining strata; and
the material between is charged with ferruginous compounds. The dip
changes at the valley between Mts. Pleasant and Clinton to 68° S. 47° E.,
and ferruginous strata are to be noted here. Half a mile before coming
to Clinton the dip is 80° N. 73° W. Mt. Clinton shows granitic and de-
composing gneisses. The dip is N. 73° W. at variable angles, and the
direction is also irregular. Between Mts. Clinton and Jackson the rocks
stand about 80° N. 62° W., and are coarse feldspathic mica schists. After
passing Clinton the following successions of strata occur on the bridle-
path : At three and a half miles, near the summit, micaceous rocks, with
acicular hornblende crystals; at three and one twelfth miles, granitic
gneiss ; at three and one sixteenth, granitic gneiss ; at two and a half,
coarse mica schists ; at one and a half, granitic gneiss coarser than the
"Concord;" the same at half a mile, with the dip 56° W. and S. 80° W.
On the east side of the Crawford house is Gibbs's brook, which falls over
ledges of coarse granitic gneiss and grayish mica schists, half a mile or so
from the hotel, and the place is known as Gibbs's falls. This location is
just below the half-mile station on the bridle-path mentioned previously.
At the Gate of the Notch the rock is the feldspathic mica schist of the
Montalban series. The railroad excavations are making the character
and position of the rocks much better known here than formerly. The
proper dip seems to be 65° S. 80° W. The Elephant's Head is composed
at its northern base of a granitic gneiss, which has been extensively
utilized for the building of railroad culverts. Other rocks of different
ages crowd themselves into the Notch, which must be noticed further
on. A trip up Mt. Webster, starting from the road at the Silver cascade,
revealed the following facts : Upon the road there are Montalban schists.
At the base of the cascade there is a granitic rock, with scams dipping

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 23

15° S. 17° W. This possesses peculiar mineral characters, whose de-
scription is reserved for another chapter. A small dyke cuts this, and
seems to have determined the course of the Silver stream, as may be
well seen in the heliotype of this cascade. Two or three hundred feet
above the road I observed a mass of mica slate, ten feet long, seven feet
wide, and three feet thick, imbedded in the granitic rock, and smaller
pieces of the same material may often be seen enclosed in this matrix.
Veins of feldspar show themselves higher up. After getting well up on
the flank of the mountain, among the small trees, there is a series of
pools along the brook where foliated planes of mica schist dip 70° N.
57° E.; but these may not be the lines of stratification. This soon passes
into the usual rock of the range, continuing to the crest of the ridge,
dipping 70° north-westerly. The route taken may be understood by re-
ferring to the heliotype opposite page 79, Volume I. We passed through
the Notch, leaving the Elephant's Head to the left, and at about a quarter
of a mile below the Gate commenced the ascent, taking a direct course
for the highest part of the central mountain in the background. The
common rocks of the Montalban group occupy every part of this view
to the left of the Gate, and a short distance to the right. The beginning
of the steeper slope very near the summit of Mt. Webster indicates the
line between the ferruginous mica schists on the left, and the eruptive
granites of the Pemigewasset series on the right.

On the top of Mt. Webster the rock is the ferruginous variety ob-
served on Mts. Pleasant and Franklin, traversed by veins of two or three
feet thickness of coarse granite and dykes of white-colored trap. South
from the north edge of the mountain the dip of the schists is 70° N. 6^°
E. One can walk along the crest of this ridge and enjoy a fine view of
the Saco valley below Mt. Willard. The summit is devoid of trees ; and
there is a precipice several hundred feet deep which is entirely composed
of the schists. At its base the granite begins ; and the difference be-
tween them is marked still further by a great contrast in color, — reddish-
brown against grayish-white. Opposite the Willey house the strata may
be said to dip westerly, though, as the dip varies but a few degrees from
perpendicular, the occurrence of a leaning to the east or west cannot be
of much consequence in the study of the stratigraphical position. The
small variations are often due to disturbances induced in connection with

124 STRATIGRAPIIICAL GEOLOGY.

large veins of granite, whicli are very common here. I tliink the usual
granite on the west side of Mt. Webster is the variety to be described
as the "Conway;" but my notes speak of the recurrence of the hard
siliceous granite of Silver cascade, east of the Saco river, and that it
extends as far as the first bridge over the river below the Willey house.
The schists do not extend to the south end of the Webster range, their
jolace being taken by the granite which occurs upon Mt. Washington
river, about as far north as the latitude of the Willey house.

Mt. Deception range. There remains to be noticed a triangular area
to the north-west of Ammonoosuc, or the eastern part of the Cherry
Mountain district, consisting of Mts. Mitten, Dartmouth, and Deception,
with their northern slope to Israel's river. Mt. Mitten is composed of
the same coarse feldspathic mica schist as Mts. Adams and Jefferson.
It is the first of the east and west range branching from Mt. Jefferson.
Mt. Dartmouth is composed of a granite, with small porphyritic crystals.
Mt. Deception is built up of a coarse Concord granite. Between this
ridge and Israel's river there is a long slope ; and nothing is known of
the ledges there. Along the river the rocks are concealed by thick piles
of earth; and the poor prospect of finding much solid rock there has
always debarred the most ambitious of our parties from making the
attempt. The western part of the area is obviously the boundary be-
tween the Bethlehem and Montalban groups ; and it is not likely that
any of the granites extend very far in a northerly direction. Very near
the north-west corner of Lowe & Burbank's Grant there is a corrugated
mica schist, abounding in mica, dij^ping 85° S. 23° E.

Concerning another extensive area our information is also meagre. It
is of the mountains south of Tuckerman's ravine, on the west side of
Ellis river as far as Iron mountain in Bartlctt. The rock is believed to
belong to the same system of Montalban schists that we have been de-
scribing. It was through the heart of this region that the exploring
party of Dr. Cutler made its way in 1784. We have, however, important
facts to state concerning the district of Mt. Washington river. It has
been explored three different times.

Mt. WasJiington river. This is the longer branch of the Saco above
Bemis station, but it is reckoned as a tributary rather than the main
stream. We have not visited its very source, close by the Lakes of the

GEOLOGY OF TIIIC WHITE MOUNTAIN DISTRICT. 12$

Clouds, but passed down at tlic gap between Mts. L^ranklin and Pleasant.
The rock is the usual mixture of andalusitc mica schists and granitic
gneisses at the starting-point, dipping N. 88° W., also 54° N. 48° W. near
by. These two mountains send out spurs into the valley, the northern
being longer, and the southern the steeper one of the two. About a
mile and a half down the valley between them the dip is N. GT)° W.
Lower down the dip is small to the north. The rock contains fragments
of an older schist in it. Beyond, there may be a south-westerly inclina-
tion, though this has not been satisfactorily observed. At a lower point
the dip is distinctly 60° N. ^2^° W. On the east side of Mt. Clinton, high
up, one can perceive from the valley a large, bare ledge. Where the
tributary, down which we have come so far, joins the main Mt. Washing-
ton river the ledges dip 30° N. "jt," W. Then, for half a mile, the schists
generally dip in the same general north-westerly direction, but there are
a few contorted dips in the opposite direction. The last ledge seen
before reaching the labradorite outlier dips 85" N. ST)° W.

The following represents the appearance of the ledges down the val-
ley between Mts. Clinton and Jackson, before reaching Mt. Washington
river. At the beginning of the slope the strata are about vertical, with
a strike of N. 12° E. Beyond, the dip is 80° westerly, with irregulari-
ties in the direction, and there is andalusite present. Continuing down
the mountain's side we come to a cascade twenty-five or thirty feet in
height, at whose base enters the first important tributary from the north.
The schists dip 70° S. 48° E. The rock below becomes more mica-
ceous ; and many ledges resemble the darker colored varieties seen at
Nancy's brook. At the next fall, of over one hundred feet, the rock
changes, and much resembles the porphyritic gneiss. Crystals of ortho-
clase are abundant, the dip being 70° N. 83° W. The iiner-grained part
of this rock presents a slightly talcose aspect ; and our conclusion is, that
if it requires removal from the Montalban group, it may represent the
porphyritic member of the Ikthlchem gneiss. The schists at the falls
dip both east and west, the latter being lowest down, and contain quite
large plates of mica, with a curved trap dyke. Below the falls the schists
vary in mineral composition, and I have noted the presence of a very
large trappean mass. Next, the strata are fine-grained and much jointed.
The feldspar bunches recur again just before reaching the junction of

126 STRATIGRAPIIICAL GEOLOGY.

this branch with the main river. Massive Kght-colored traps appear
here. At the fork the strata of porphyritic aspect dip only 20° a Httle
west of north; and fragments of other varieties of gneiss are imbedded
in them. A few rods above the confluence of the two streams the dip
is N. 6f E.

The occurrence of the labradorite rock is described elsewhere. The
first rocks seen below it dip thirty or forty degrees northerly, and they
are the dark-colored, twisted andalusite mica schists, with little feldspar.
Below the outlet of the brook from Clinton the strata become flinty, are
quartzites, with the characteristic White Mountain mica scattered through
them, and are inclined 45° N. 43° W. A remarkable trappean conglom-
erate is next met with. For one hundred feet on the east branch there
is an interesting trappean conglomerate, with pebbles of various Mont-
alban schists, some of them three feet in length. Seams of an argilla-
ceous cement interpenetrate them. At the lower end of the mass the
quartzose rock reappears, dipping easterly. Across the river a similar
ledge crops out, having a striped appearance, dipping 30° N. 38° W., or
directly under the preceding. Where the valley curves sharply to the
east, the hard quartzite has been cut deeply by the river, which has
shrunk to less than half its former dimensions. At a great bend below,
an enormous amount of drift is exposed high up on the southern bank.
At this point the ledges of granite commence, though enormous boulders
of them are strewn by the river's side for half a mile above. This
granite is related to the "Conway" variety.

A matter of much interest may be seen below. After following a dis-
tinct granite floor for a considerable distance, — the whole gulf having
this rock upon both walls a thousand feet high, — there appears an island
of the flinty rock, which may be the remnant of the underlying material
once covered by the joasty granite, and exposed at the present time on
account of the long-continued agency of the water passing over it. The
same rock crops out again at Bemis station, about three miles lower
down. These and other facts lead us to believe that the base of the
Saco valley lies very near the base of the whole series of Pemigewasset
granites.

There is an interesting scries of falls on this river, five or six miles
above its junction with the Saco. Mr. Huntington says that the upper

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 12/

part consists of a fall of seven feet into an oval basin twenty-five feet
long and twenty wide. Then the stream makes two leaps of ten feet
each, one above the other, and finally terminates by a vertical plunge of
twenty-three feet, the body of the stream here being only ten feet wide.
Dr. Bemis narrates interesting expeditions to this locality, and found
trout in abundance considerably above these falls. His companions, —
among them the elder Crawford, — seemed to have great fears of the evil
spirits that kept guard over the source of this mountain torrent.

Country East of the Peabody and Ellis Rivers.

BY J. H. HUNTINGTON.

Beans Purchase, Chatham, etc. The great area of country stretching
southward from the Androscoggin river in Shelburne is for miles a wil-
derness, uninhabited save by the denizens of the forests. It is broken
by hills and valleys, rocky cliffs and deep gorges, mountain ridges and
precipitous slopes ; while on the west side of Bean's Purchase, and on
the state line near Chatham, we have mountains that rise to the height
of nearly four thousand feet. In Chatham and Jackson the country is
hardly less broken. The gorge between Mts. Wildcat and Carter is quite
as remarkable as any among the mountains, especially in its southern
opening. The precipitous wall of rock on the west, the over-hanging cliffs
on the east, the great mass of debris across the valley that confines the
water of a small lake, are all of intense interest to the geologist. On the
east the Bricket notch, just over the border in Maine, is remarkable, par-
ticularly in the way in which the streams divide as they come down from
the side of the Notch. The stream from Mt. Royce, where it leaves the
steep slope of the mountain, divides ; a part runs north into the Andros-
coggin, and the rest flows south into the Saco. But what is most won-
derful, from Speckled mountain, on the south-east side of the Notch,
there is a stream the exact counterpart of the one from Mt. Royce ; — so
that the height of land in the Notch is an island by being surrounded by
water from these two streams, or rather four streams, after the two have
divided. At the head waters of the east branch of the Saco there is a
low notch towards Wild river, and the slopes of the sides are regular,
compared with most notches about the mountains.

The irregularity of ridges and mountain ranges in this section is due

J 28 STRATIGRAPIIICAL GEOLOGY.

chiefly to the changes in the strike and dip of the strata. While in
general the strike is not very far from north and south, there are many
notable exceptions. The most marked is at the head of Cold river, where
the strike is nearly east and west, and the dip is north, nearly vertical.
A change in the strike causes the mountain ridge to sweep round in
a curve towards Baldface mountain. Between Ellis river and Wildcat
branch there is a sharp mountain ridge that runs nearly north and south,
extending down from Wildcat mountain. This ridge has in places a
height of two thousand feet. East of Wildcat branch there is a ridge,
including Black mountain, that is somewhat higher than the last. The
other well-marked heights in Jackson are either granitic gneiss or in
part intrusive rocks.

The rocks of Bean's Purchase, Chatham, and Jackson are for the most
part quite uniform. The entire range east of the Glen road, including
Mts. Moriah, Imp, Carter, and Wildcat, is composed of the White Moun-
tain gneisses. These rocks extend from this ridge eastward into Maine ;
and the mountain ridge including Mts. Royce and Baldface is the same.
The rock in the area between Baldface mountain and the site of the
Dearborn & Philbrook saw-mill is a feldspar-porphyry, with a limited
outcrop of a dark-reddish, more compact feldspathic rock on the south-
west side of Sable mountain. This last has sometimes the appearance
of being a breccia, and resembles the feldspar-porphyries of Mote moun-
tain. Though not seen in many j^laces, it probably extends southward
to Mountain pond. Both south-west and north-east from Mountain pond
the rock is a reddish granite. Slope mountain is probably its limit north-
ward. South of Chatham Centre we find a granite very similar to that
of Conway, while in the north-east part of the town, north of the Cen-
tre, the rock is generally the gray micaceous gneiss of the Montalban
group, though on the east side of Baldface a granite has been quarried
that contains quite a large proportion of feldspar. The dip of the gneiss
is quite variable. Half a mile north-west of Chatham Centre it is N. 3°
E, 68°. Just above the school at the base of Slope mountain the dip is
N. 37° E. and E. 56°. It has been affected here, no doubt, by a great
granite mass on the west. On the south slope of Mt. Royce, where an
observation was taken, the dip is N. 13'' W. 20°; but, from the precipi-
tous character of the mountain, the inclination of the strata must be

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 29

much greater in many places. Passing over into Maine, the rocks of the
Montalban group, where they were seen in Stoneham and Lowell, have a
westerly dip, generally at a small angle.

West of Chatham in Jackson, Double Head is granitic gneiss, probably
an extension of the Montalban southward from the Dearborn & Philbrook
sav/-mill, but it is limited southward by the intrusive rocks in the south
part of Jackson and in the edge of Bartlett.

Valley of the Ellis river. From the height of land in the Pinkham
notch southward to Jackson village, the White Mountain gneisses are
the prevailing rocks. Though the inclination of the strata is everywhere
westerly, yet the dip is quite variable. At Glen Ellis falls the dark gray
gneiss dips N. 60^ W. 45^ and N. 83° W. 60°. At the head of the falls
there is a wide quartz vein that is metalliferous and somewhat decom-
posed. A fine view of these falls is given in Volume I, opposite page
632. The massive character of these White Mountain gneisses is no-
where better shown; and the jointed structure is in a measure brought
out in the view. On the west of the road, as we begin to descend the
hill going southward, the rock contains andalusite ; and a few beryls have
been found in the coarse granite veins that cut this rock. Going south-
ward, we find the dark gray gneiss common to this mountain region ; and
at the distance of two miles from the falls the dip is N. 23° W. 60°. At
the first house in Jackson, — N. M. Cook's, — the gneiss has in several
localities an impure limestone interstratified with it. It can be seen east
of the road, on a steep hillside about eighty rods south of the house, also
in the river at a sharp turn below the house. The rock near the road
dips N. 33" W. 45°; and the limestone with gneiss east of the road dips
N. 20° W. 85° In the river where the limestone is found the dip is ex-
ceedingly variable. At H. Wentworth's the White Mountain gneiss dips
N. 38° W. 25°; and on the west side of the road the strata dip N. 65°
W. 30°. On Miles brook, at the falls, the rock does not look like the
White Mountain rock elsewhere. It contains very little mica; the cleav-
age planes are very distinct, and the rock is broken by them so that the
water falls over stair-like projections. In the vicinity of J. Rogers's there
is an extensive outcrop of granite like that in Albany. The cliff west of
Ellis river is made of this rock. The stratified rocks south of Rogers's
seem to be more siliceous than the White Mountain rocks generally,
VOL. II. 17

130 STKATIGRAPIIICAL GEOLOGY.

though on the ridge east of the road they have their normal character-
istics. West of Ellis river, and on the east slope of Iron mountain, we
have a rock very similar to that on Miles brook, and it has here an east-
erly dip ; while on the summit of Iron mountain the common White
Mountain gneiss dips north. On Wildcat branch, at the most northern
settlement, we have the characteristic White Mountain gneiss; but on
the western slope of Black mountain, at J. Y. Perkins's, and south at J.
R. Harriman's and J. Cheslcy's, there are many bands of fine-grained
pyritiferous schist, and at Chesley's there is a dark siliceous schist free
from iron. On the southern slope of Black mountain we have the anda-
lusite schist. On Rocky Branch, above Abt. Emery's, the gneisses are
everywhere pyritiferous.

The following additional dips show how exceedingly variable the strata
are in this area.

Three and a half miles north of the Dearborn & Philbrook saw-mill,

White Mountain gneiss clips N. 85° E. 50°.

George Manson's, White Mountain gneiss dips . . . . N. 72,° W. 60°.

N. M. Cook's, limestone in the river dips N. 78° W. 20°.

" " gneiss near the limestone dips .... N. 30°.

Miles brook, at the falls, dip, N. 34° W. 42°.

J. W. Brack's, White Mountain gneiss dips N. 38° W. 64°.

A. Chesley's, pyritiferous schist dips N. 33° W° 68°.

" half a mile north-east of house, siliceous schist dips, S. 38° E. 66°.

Near the last, dip, N. 43° W.

Summit of Iron mountain. White Mountain gneiss dips . . . N. 53° W. 25°.

Three miles west of Jackson, road to Rocky Branch, dip, . . N. 13° W.

The variation is due in a great measure to the fact that the stratified
rocks have been folded, and pressed against the harder, unyielding intru-
sive granitic rocks. We have already mentioned that a dark siliceous
rock was found near A. Chesley's. A similar rock is found on Tin moun-
tain, in the gap west and on the east side, and near the summit of Thorn
mountain. It is also found near the village of Jackson, immediately
north of the falls.

On Tin mountain, dark siliceous schist dips N. 47° E. 80°.

Hill west of Tin mountain, siliceous schist dips . . . . N. 7° E. 70°.
Thorn mountain, siliceous schist dips N. 17° E. 68°.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I3I

These schists that come near or in contact with intrusive rocks are
everywhere nearly vertical.

Intrusive rocks. In the south part of Jackson, and also running diago-
nally across the town, there are bands of intrusive rocks. On Wildcat
branch, where the road from A. Chesley's crosses the stream, there is
a granitic rock composed very largely of feldspar. The rock has the
general appearance of the Albany granite, which outcrops on Ellis river,
near J. Rogers's, and a large proportion of this rock is also feldspar.
An outcrop of a similar rock was seen at C. Littlefield's, and it extends
to Rocky Branch. At Jackson falls the Albany granite is found, with
finer-grained varieties. It outcrops in several places on the ridge be-
tween Tin and Thorn mountains. It also forms the summit of the latter.
On the east branch of the Saco, just below McMellin & Towle's saw-mill,
the Albany granite comes in contact with the slates of Mt. Pequawket.
Along the line of junction the slate forms a breccia, and the feldspathic
material of the granite furnishes the cementing material. It is one of
the most interesting localities in this section of the state. There is an
area of the Conway granite that has its most northern and eastern out-
crop on Copp's hill in Jackson. It extends south-west, and forms the
southern part of Iron mountain, and it is in this rock that the iron ore is
found, though it is immediately associated with a rock composed chiefly
of feldspar, that reminds one of the Chocorua granite. If the granites
that are composed so largely of feldspar are more recent than the Con-
way, as seems evident from their relations elsewhere, those that we
find in the valley of Rocky Branch, between the high ridges of the Con-
way, must have been formed in a depression, or the intruding mass had
not sufficient force to make its way through and overflow the preexisting
rocks. J. H. H.

Areas of Montalban in Pemigewasset.

These areas are six in number: — First, the region about Bemis and
Duck Pond mountain; second, a small patch between Deer mountain
and Chocorua; third, a somewhat larger territory between Passaconna-
way and Tripyramid, on the east branch of Sabba Day brook ; fourth, a
considerable tract along the Pemigewasset river in Lincoln, Woodstock,
and Thornton, being a spur from a great development of this formation

132 STRATIGRAnilCAL GEOLOGY.

in the Merrimack district; lastly, inconsiderable areas in Albany and
Bartlett.

A trip up Mt. Hope and the mountain opposite Nancy's brook in
Hart's Location affords us a few observations concerning some of the
rocks of the first-named area. Starting from the Saco river by the old
Davis path, the common granite of the Notch is seen half-way up Mt.
Hope. This is followed by a porphyritic rock (No. 430). Mt. Hope is
a small eminence at the head of Glen Crawford, just south of Mt. Craw-
ford. The Glen is shown in the hcliotype of Mt. Crawford from Bemis.
Mt. Hope and the southern part of Mt. Crawford are composed of fine-
grained compact feldspathic mica schists, dipping 60° N. 3° W. This
area is marked like Mt. Webster by the occurrence of enormous granite
veins, with the direction N. 8° W., and some of them are at least thirty
feet wide. These veins are supposed to have been connected with the
eruption of the Conway granite. Some of the specimens from Mt. Hope
are micaceous quartzites. On the south side of this eminence the gran-
itic gneisses predominate, with only an occasional layer of the quartzite.
Passing to the next mountain south, the schists dip 75° N. 52° E., also
N. 23° W. Occasional masses of granite show themselves. On the very
highest point of this mountain, and opposite to the mouth of Nancy's
brook, the rock is like the common Mt. Washington schist, with a few
spangles of fine mica among the abundant larger pieces. The specimen
has a reddish color, from ferruginous stains. The dip is 70° N. ^8° W.
In passing down to Nancy's brook, rocks similar to those on the summit
show themselves, with essentially the same position. Half-way down
there is much of a hard, jointed granite. At the western base of the
mountain the rock agrees with that on its highest part.

The rocks are well exposed on Nancy's brook. At its mouth the
railroad passes through a large cutting, and the fragments thrown out
may be taken as typical of an important variety of this formation. The
color is mostly dark, nearly black, with a whitish sprinkling of feldspar
or quartz. The substance is largely a compact silica, but the mica is
well developed, and is not quite so conspicuous as the blotches on the
presidential summits. The mica is often distributed in impalpable shin-
ing streaks instead of scales. At the saw-mill the dip is 45° N. 87°
W. The brook has excavated a flume through the ledge, and the rock

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 33

removed is a granitic aggregate, very siliceous, like the exposures in the
Silver cascade and elsewhere in the White Mountain Notch. The flume
exists because of the removal of this dyke, twenty-five feet in width.
The vertical joints of the walls have the direction of N. 62° E. It is
well known to tourists, and has been figured in Oakes's work on scenery.
Half a mile up the stream the rock is micaceous quartzite. The speci-
mens brought from various localities higher up, the last mile and a half
east of Nancy's pond, are gneissic (Nos. 310, 311, 313). At Bemis sta-
tion a dark rock appears, with the same general position as the strata at
the saw-mill. A comparison of those already mentioned as coming from
Mt. Hope, the ridge south, Nancy's brook, and Bemis station, with the
rocks of Mt. Webster and the lower part of Mt. Washington river, proves
them to be identical in appearance and composition.

Below Bemis this rock may extend nearly to Sawyer's river. At the
most prominent bend in the Saco, about a mile and a quarter below
Nancy's brook, some large ledges dip 75° N. 73° W., with many contor-
tions. In the sai^Tie neighborhood the railroad has uncovered a ledge
dipping N. 80'' W. Dr. Bemis says there is a slaty rock of this descrip-
tion on Half-way brook, higher up the mountain. Duck Pond mountain
is supposed to be composed of the same materials, as I found ledges of a
gneiss with much silica in it about a mile above Sawyer's river, on Duck
pond, dipping 80° S. 60^ W. Three fourths of a mile farther north-west
the same rock occurs. Scarcely anything can be said respecting the
areas west of Mts. Chocorua and Passaconnaway. Both show a high
westerly dip. The first is clearly the ordinary schist of this series. The
specimen from the other locality is a somewhat ferruginous micaceous
quartzite.

In the report for 1871 it is stated that there is an outcrop of this
formation upon the head waters of Little Deer brook in Albany. Our
specimens from this locality very closely resemble the schist commonly
characterizing this group. The outcrop is quite limited, lying between
feldspathic porphyry and feldspathic breccia. Another small area has
been discovered upon Rocky Branch in Bartlett.

Peinigcwasset River area. The assemblage of gneisses and granites at
the Georgianna falls in Lincoln may possibly belong to this series, though
noticed under the Franconia breccia. It is probable that the Montalban

134 STRATIGRAPHICAL GEOLOGY.

schists extend about to the cascade, though none of our specimens came
from a mile and a half beyond the neighborhood of the Lincoln post-
office. At the post-office the dip is 50° N. 57° W. Section VIII shows a
profusion of specimens belonging to this formation between the Pemige-
wasset river and the granite, a quarter of a mile east of T. C. Pollard's.
The gneissic character is well shown in most of the specimens ; and the
dip near Pollard's is about eighty degrees north-westerly. At P. Russell's,
in North Woodstock, the gneiss dips 70° S. 73° E. It is traversed by a
trap dyke six feet wide, also by a thirty-feet band of granite. Near J. M.
Rowe's a similar rock somewhat ferruginous dips y8° S. 38° E. Passing
from the Pemigewasset to Russell pond we see first a variety of unclean
gneisses and mica schists dipping 70° S. 63° E. A little south-west from
the pond there are mammoth veins of coarse graphic granite carrying
beryl, rough quartz crystals, and plumose mica. The strata somewhat
to the south stand upon their edges, with a north-south strike. East of
the pond a gneiss containing garnets dips 50° N. 42° W. Still farther
east the rock is ferruginous on the west side ; and there is a large vein of
granite on top of a ridge, not the highest part of the water-shed. Just
below Woodstock, P. O., an imperfect gneiss dips 80° S. 82'^ E., with
many contortions. At Norton's falls there is an anticlinal in a granitic
gneiss, possibly belonging to the porphyritic series, with the strike N.
13° E. This may be the northward continuation of the axis mentioned
on page 102.

At E. Merrill's, in the north part of Thornton, there is a coarse granite
with gneissic layers dipping 60° S. 18° W. Near Mrs. G. W. Grant's the
rock is ferruginous. South-west from H. Fifield's, on the Woodstock
line, the gneiss dips 65° N. 52° W. In the direction N. 8° E. from
Fifield's there is an enormous vein of coarse granite east of the ridge
running up to Russell pond. There is a low gap in the rim of the Pemi-
gewasset which is 904 feet above the sea, and not more than fifty feet
higher than Fifield's house. The ridge rises steeply to the north, and
the schists there arc not uniform in position. Hix and Wanosha moun-
tains in Thornton are small eminences of the Montalban gneiss, and they
are by no means the formidable summits they seem to be on the county
map. Between them, near M, Sargent's, the rock is considerably ferru-
ginous. At J. F. Morrill's, at the end of the road, the gneiss dips 70° N.

Ti.^tt: VI fL

IMM

GjLeisa with Lobradoi- Sy^Wt,, ; Mount N
"Wtx&hiiigtoii River. ctf

Ktf . 10.

rx ^. , f-» ri<^- 13. 3ertiojv froaiv Lower Ammon-ooaitc

Old Man of Dixvilue:. niver to TVIt. Httle.

Tripjrr ciwiia.

^tffot

O SSIPYTE

-^

r^^T:r^^ V ^oVjdte' ■ i-e^i^^^r^''^^^^?^^

Kg. 19. StTTXcture o:f TxipyTawLicL Moiirttaii^-.

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./

/VL B A IV.

Pi^. 12. Section fraitv We.^t TXorntoji to Welck MoiLrtt/iin-^.

,4-

.ePQES EXPOS

Fi^. 11. Section, from 5.E. Daltou thj-ou^Ti Whitcfiel^ <md. Carroll.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 35

72° W. At the saw-, shingle, and clapboard mill on the Woodstock line,
gneiss dips 80° south-easterly. South of Hatch hill, on the road east,
there are Montalban schists resembling those found farther north.

The immediate vicinity of the Pemigewasset is occupied by porphyritic
gneiss noticed on page 102. There is an interesting section between
Welch mountain and the river at West Thornton, represented in Fig. 12.
At the westward is the Pemigewasset river, with its alluvium nearly to
H. K. Hill's house. The underlying rock is the porj^hyritic gneiss, with
a very high easterly dip, nearly vertical, — the other part of the anticlinal
axis existing on the west bank of the river, and not represented. The
strike is N. 38° E. The hill is the continuation southerly of the east
water-shed of the river, and not a rock boundary. As soon as we come
to Mill brook the rock changes to the Montalban schists. At W. Graves's
they dip 85° south-easterly, and are much contorted. A similar position
is noted all the way to Welch mountain, but especially at the school-
house east of J. P. Sanborn's. Cone mountain is composed of the same
rock. This designation is derived from the name of a person, and not
from any resemblance to the well-known geometrical solid. At E. F,
Elkins's the rocks are concealed ; but we pass up the steep slope of
Welch mountain, which is composed of Albany granite in broad plates
dipping twenty degrees westerly, and supposed to overlie the Montalban
group. The lower granite was not observed at this point.

This section illustrates, first, the mutual relations of the three rocks
named. Supposing them to lie in their natural positions, one sees clearly
that the porphyritic gneiss is the oldest formation, and possesses an
anticlinal struxture, while the same uj^per schists appear on both sides
of the axis. The granite assumes the overlying, slightly inclined position
argued for this rock almost universally in New Hampshire. Second,
there is such a divergence in the strike of the porphyritic and Montalban
groups in Thornton that one may be justified in inferring that there is an
unconformity between them. The strike all through the central forma-
tion of the section is north-easterly. The course of the boundary between
them is N. 10° W. The most common strike of the porphyritic gneiss is
a little east of north, but at V. G. Durgin's the longer axes of the crystals
run nearly east and west. Assuming the correctness of these statements,
it may be inferred that the Montalban schists lie upon the upturned edges

136 STRATIGRAPHICAL GEOLOGY.

of the porphyritic gneiss over the whole area between the Sandwich and
Pemigewasset River ranges ; and, as the boundary Hne between tliem
conforms to the strike of neither, it is Hkely that they are not divided by
a fault, but the irregular edge is due to unequal erosion by atmospheric
agents. Nevertheless, the line is straight enough to have been deter-
mined by a fracture; but even in that event the two formations must
have been unconformable to each other. The very easterly directions of
the strata at H. K. Hill's and V. G. Durgin's would seem to indicate
the passage of the porphyritic rock directly underneath the Montalban
gneisses along the line of strike. A similar course is probable for the
very interesting outcrop of the older rock in the Pemigewasset river
along the boundary between Thornton and Campton. Upon Section
VII will be found a representation of the situation of this rocky blanket
upon the porphyritic floor.

Little search has been made for the mineral andalusite in this range.
There is, however, an outcrop near E. Cone's, at the crossing of the road
by a tributary of Mad river, near a cemetery, showing either this mineral
or kyanite sparsely scattered through the ledge. The dip is 60° S. 42°
E. It is rare to find ledges in this part of Thornton, on account of the
abundant loose materials spread everywhere over the surface. Passing
southerly beyond the limits of the White Mountain district, this forma-
tion assumes a much greater importance, and covers an immense area.

Eruptive rocks. There is much to be learned from the study of the
various eruptive rocks connected with this group. In the absence of a
proper study of their lithological characters, little attention has yet been
devoted to them. Hence they must be referred to again in another part
of the report in the department of mineralogy.

One of the most important areas of eruptive granites intimately asso-
ciated with this group lies between the Portland & Ogdensburg Railroad,
north of the Notch, and the base of the presidential ranges, including
Mt. Deception. The great contrast in the topographical features of this
granitic region with those of the harder schists may be well apjDreciated
by reference to the view of the Mt. Washington range from the P^abyan
turnpike. Vol. I, p. 392. The whole of the foreground is granitic, and of
two varieties, different from those in the Pemigewasset series. That
from the Mt. Deception range resembles the Concord gneiss, save that

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 37

it is coarser, and, so far as examined, seems to be a true granite. This
variety prevails in tlie western part of tlie territory mentioned above, and
may also be seen along the Ammonoosuc as far as Twin river. The other
variety occurs extensively from Jefferson brook past Ammonoosuc station
along the base of Monroe, Franklin, and Pleasant. It consists of a gran-
itic aggregate much like the other variety, having two kinds of mica and
especially long, slender feldspar crystals scattered throughout. In pass-
ing along the turnpike above Twin river one sees numerous boulders of
this variety, in which the long, slender feldspar crystals are conspicuously
brought to view through weathering. This rock does not extend above
the junction of Franklin with Pleasant brook, with seams dipping io° N.
47° E. Below it are great masses of feldspathic mica schists, and abun-
dant evidence of its intrusion through strata. It is thought the schists
do not extend very much below Franklin brook. Between the lowest
schists and Twin river the outcrops are altogether of this variety of
granite. Near the "White Springs" on the turnpike there are seams
with a high westerly dip, and the rock is quite ferruginous.

On the west side of Mt. Webster, between the Notch and "Pleasant
River bridge" over the Saco, there is developed a granitic aggregate of
quartz and feldspar, the former predominating. Its eruptive character is
inferred from the presence in it at various localities, particularly on the
Silver stream, of large fragments of micaceous quartzite, and to its oc-
currence as a dyke at Bemis's saw-mill at the mouth of Nancy's brook.
The occurrence of this granite is a marked feature in the geology of
the Notch.

The enormous brecciated traps on the Mt. Washington carriage-road
and at the Crystal cascade, the light-colored dykes in Tuckerman's ravine,
Mt. Webster, the valley of Mt. Washington river, and elsewhere cannot
be treated of satisfactorily at present. At a saw-mill rather more than a
mile above the mouth of Rocky Branch in Bartlett, are large trappean
dykes containing fragments of three kinds of granite. They may be
related to the Mts. Pequawket and Mote porphyries.

The Fkanconia Breccia.

The most notable locality of this rock is just above the celebrated
Basin in Lincoln. Innumerable pieces of porphyritic granite, dark gneiss,

VOL. IL 18

138 STRATIGRAPIIICAL GEOLOGY.

hornblende, and other siHceous rocks are cemented together by a hght-
colored feldspathic paste. The Conway granite Mes upon it, the lower
formation dipping south-westerly. The line of junction is uncommonly
distinct, not being so much as a rod away from the Basin itself, which is
so much visited by tourists. Hence it is a locality easily reached by all
who are interested in determining the relations of the New Hampshire
formations to one another. As the breccia is the material which fur-
nishes information respecting the age of the formation, this will be a
favorable place to commence our inquiry. Although mountains surround
this valley upon every side, only a few of their ledges arc represented in
the recomposed rock. Neither the Conway nor Albany granite, the por-
phyries nor the labradorites of Mts. Lafayette and Profile, appear in the
breccia. The Montalban group is not certainly known in the neighbor-
hood, so that we should not expect to see its fragments abundant in the
mixture, even if it had a prior existence. It is my impression, however,
that I have seen genuine Montalban fragments in this rock, and for that
reason I placed the Franconia group later in the chronological scale ; but
I can now find no specimens among our collections to justify this conclu-
sion. The absence of the Pemigewasset series of granites and porphy-
ries is of much significance, indicating their appearance upon the surface
at a later period.

This formation ranges from Mt. Haystack in Franconia to Georgianna
falls in Lincoln, a distance of over nine miles. Besides the fragmentary
character already noticed, it is composed of an indurated schist very
similar to the porphyritic gneiss of this neighborhood. Quartz, feldspar,
and black mica are usually present, while every exposed ledge has a
slightly rusty appearance from the oxidation of iron. Associated with
these gneisses are finer-grained granitic layers, which are not of much
importance. The ledges at Haystack pond and on the first eminence
between Mts. Lafayette and Haystack, as we proceed northerly from the
first-named peak, show the common gneissic variety of this formation.
Nothing is known of their position in these two localities, but we sup-
pose both are united together and to the Eagle Cliff range, which over-
looks from the north-east the celebrated Profile of Franconia.

Travellers from ]3ethlehem and Littleton always notice the irregular
ragged cliffs filling up the notch between Mts. Lafayette and Profile, as

^M-^

140 STKATIGKAPIIICAL GEOLOGY.

to the west, the succeeding ledges of Bald mountain being very porphy-
ritic.

Although the positions are often obscure, it appears plain that, from
the passage of the Eagle Cliff ridge by the Lafayette road, to Echo lake,
there is a mixture of hard gneisses, with a feldspathic breccia dipping
underneath the porphyritic gneiss. As the breccia is largely composed
of porphyritic fragments, it must be of more recent origin than the other
rocks, although occupying an inferior position. Our conclusion is, that
there is an overturn along this ridge, and a fault at its eastern extremity.
That will allow the existence of the anticlinal described heretofore and
figured on Plate VI, Fig. 7, and will explain the position of a newer be-
neath the older formation.

At the base of Eagle cliff is a good place to procure specimens of the
rocks that have fallen down from above. Opposite the Profile I saw
fragments of porphyritic gneiss in the paste twenty inches long. Certain
specimens ringing sharply under the hammer exhibit crystals of quartz
in the feldspathic paste. A dyke of trap two feet wide, a little to the
east, dips 75° S. 78° W. There are only a few outcrops of this forma-
tion between the Profile house and the Basin. At the latter locality there
is a trappean-looking rock east of the road connected with the breccia.

This formation has not been seen beyond the Basin in connection with
any other area, though there is an opportunity for further explorations on
the east, above the porphyritic gneiss. Conway granite covers this rock
on the west along the outlet of Tamarack pond. On the height of land
between Mts. Profile and Kinsman the breccia is largely developed. Of
the three peaks along this line the most northern is of granite; the
others are composed of this breccia, whose component materials average
coarser than at any other locality now known. The middle peak is
gneissic ; the third, and the valley preceding it, abound with fragments
of porphyritic gneiss twenty inches square.

A trip to Kinsman pond, back of Mt. Pemigewasset, shows the same
breccia, it being probably continuous from the peaks south of Mt. Profile.
The rock did not appear in place ; but the great size of the angular blocks
indicates the character of the underlying material.

The last line of outcrops referable to this formation ajjpears upon Har-
vard brook in Lincoln, above Georgianna falls. Mr. Upham visited the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 141

locality in 1870, and brought back an abundance of notes and specimens,
which enabled me at that time to "refer the assemblage to this period.
Harvard brook is about three miles long, rising on the south-east side of
Mt. Kinsman in Bog pond. Less than a mile from its source a small
tributary enters from the north. Upon this and near the main stream
there is a vein of quartz three feet thick, dipping 80° E., imbedded in
the gneiss. Below the junction of the stream is the "Bog Eddy," an
extensive marsh. Between the bog and the upper fall occurred the fol-
lowing: Gray granite, with two kinds of mica; irregular, very coarse
granite, with masses of feldspar and quartz frequently eighteen inches
long; the ordinary gneiss with black mica, much jointed; coarse granite
eighteen inches wide, with the course N. N. E. ; similar rocks for ten
rods ; a coarse granite bed one foot wide dipping, like all above it, 60°
south-easterly; fine-grained granite eighteen inches wide, dipping sixty
to seventy degrees north-westerly, in which particular the rocks below
resemble it ; coarse granitic rocks for ten feet. The gneiss at the upper
Georgianna falls resembles somewhat the prevailing rock of Woodstock,
which has been referred to the porphyritic gneiss. The main falls are
situated upon the Franconia rock traversed by a two-feet dyke of coarse
granite. [See Fig. 41, Vol. I.] The banks of the stream between the
falls and its junction with the Pemigewasset have not been explored.

It is probable that the Franconia breccia is a local deposit, though it
indicates a great disturbance among the more ancient formations. There
must have been a violent action to break up the older ledges into such
large pieces, and transport them to their present bed. If you believe
in the transformation of the original sediments by metamorphism into
the crystalline aggregates from which the pebbles were broken, it follows
that the porphyritic and perhaps other gneisses underwent their changes
prior to the Franconia period, since the fragments have experienced no
modification in mineral character after leaving their original situation.
It is hoped that some traces of this period will be found elsewhere in the
state before our explorations are finally brought to a close. Perhaps it
is represented upon Cascade brook above Beecher's falls.

142

STRATIGKAPHICAL GEOLOGY.

PEMIGEWASSET SERIES.

In Chapters III and XV of the first vokime I have set forth in a his-
torical way the reasons which led me to describe the Pemigewasset series
of rocks, chiefly eruiDtive, as the probable equivalents of the Labrador
system of Logan and Hunt. I stated finally that the several rocks were
arranged in the following order, beginning with the lowest: Conway
granite, Albany granite, Chocorua granite, Ossipyte or labradorite rocks,
and various compact and crystalline feldspars or porphyries. Owing to
their particular geographical grouping, I believed all these members to
constitute parts of one grand system. This conclusion was derived from
the study of the specimens obtained from every part of the White Moun-
tain district, and was not properly comprehended till the field-work had
been essentially completed. There are difficulties in the way of accept-
ing these views, and I desire to investigate the subject further before
committing the report to the view already presented. I will not, how-
ever, depart from the established order in the description of localities and
other important matters, only premising that there may be some modifi-
cations of our general conclusions hereafter. One is often staggered
when attempting to realize the greatness of the task imposed upon us, —
to delineate truthfully the geological sequence of all the formations in
this unexplored territory. The difficulties in the way must bespeak the
indulgence of the scientific public in our favor, should we fail to discover
fully the true theory of the structure of the White Mountains.

The Conway and Albany Granites.

It will be convenient to describe both of these granites together, when
speaking of their occurrence on the sides of the mountains, and thus
avoid needless repetition.

The Comvay granite was first described as the "common" variety in
the report for 1871, page 6. Its type appears at the Basin, Pool, and
Tlume in P'ranconia, Goodrich's falls in Jackson, and throughout the town
of Conway. The minerals composing it are the three normal constitu-
ents of granite, — quartz, feldspar, and mica, — each one being well devel-
oped, and so large as to be recognized without difficulty. The microscope

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 43

is not needed to determine the particular mineral species present. The
feldspar is mainly a flesh-colored orthoclase, but oligoclase is common in
Franconia and Conwa}^ and probably universally. I have also observed
that the quartz is rouij;hly crystalline, whenever carefully examined. The
mica is thought to be an ordinary dark muscovite. There are many
subordinate varieties connected with this mass, v>^hich will be noticed at
the proper time; but the typical rock known as the "Conway" is the
best example of a real granite found in the state.

The Albany granite was first brought to notice at the same time with
the other, in 1871, but received the designation of "trachytic," in allusion
to a slight resemblance to the volcanic product known as trachyte. It is
porphyritic in structure, having crystals of orthoclase imbedded in a fine
granitic paste. Two prominent varieties should be noticed, — the one
carrying bits of quartz, the other entirely devoid of it; and in this latter
case containing the mica disseminated through it, looking as if the rock
had been sprinkled over with pepper. The latter variety is the more
abundant of the two. A small per cent, of manganese is often present.
The porphyritic crystals from Albany gave to Prof. Seely, of silica, 61.6;
of alumina, 22.2 ; of lime, .8. The other percentages were not determined.

In regard to the distribution of these granites, it may be said in gen-
eral that they occupy the area bounded northerly by the Ammonoosuc
as far as the Crawford house, then easterly by Mt. Webster, from whence
the northerly boundary passes easterly to Chatham. From Chatham the
line passes east of Mt. Pequawket, and takes in the Green hills of Con-
way. The Hne then curves westerly from the south part of Conway to
Waterville, whence it passes north-westerly and northerly to the Basin
in Franconia, and above the Lake of the Clouds on Mt. Lafayette. From
thence the boundary is somewhat east of north till the Ammonoosuc
river is reached near the Twin Mountain house. In proceeding to a de-
tailed description of the occurrence of these rocks, I will follow the order
just indicated.

Passing southerly from the Twin Mountain house, by way of the three
"Sugar Loaves," we find, first, the ordinary coarse Conway granite. On
top of the first two peaks the rock holds more than the ordinary quantity
of black mica. Between them there is an unusual proportion of quartz
present. In the saddle between the second and third peaks the planes

144 STRATIGRAPIIICAL GEOLOGY.

dip ten degrees northerly. The fourth moiintahi (No. 5 of Fig. 32, Vol.
I) is distinctly composed of the Albany variety, the crystals of feldspar
being very numerous. I think the jointed planes dip in the same direc-
tion with those farther north. The high mountain to the south of Mt.
Hale is composed of the same material, and we do not know that it ex-
tends farther in that direction. The line connecting these several peaks
makes the arc of a circle, and the supposed position of the granites along
this curve appears in Fig. 13.

In travelling from the third Sugar Loaf transversely across to Mt.
Tom, the rock is chiefly the Albany granite. The ledges are at the east
side of this third peak, on a west branch of New Zealand river as well as
at the stream itself. The granite range north of Mt. Tom shows a pre-
cipitous cliff on the west side. This has six summits north of Mt. Tom,
of which the first and second are nearly porphyritic, being compact, with
scattered crystals of orthoclase in it. On the third summit the rock is
easily referable to the Conway. That from the fourth contains much
quartz. In the fifth the feldspar has very much of a crystalline arrange-
ment. From the Sugar Loaves the Conway granite is continuous, by
way of the lower falls on the Ammonoosuc and the several peaks just
mentioned, to the Notch. On the east slope of Tom it descends quite
low, and finally crops out on Cascade brook. The precise connection
between this point and the same kind of granite on the Saco, deep down
below Mt. Willard, will be spoken of presently. Both the lower granites
are made out clearly on the east side of Mt. Tom.

A second visit to the first part of this granite ridge north of Mt. Tom
showed that there was a long, low summit composed of the Albany gran-
ite, with jointed planes dipping about five degrees north-easterly. On
descending the mountain on the east side, this spotted rock was found to
be about three hundred feet thick, succeeded by the Conway variety,
which was followed down nearly the whole of the slope. On another
occasion we found the Albany granite occupying the saddle between
Mts. Tom and Field, as well as nearly all the space northerly to the
summit of the first named. Between this point, near the summit of
Tom, and the mountain north the country is composed of andalusite
slates, perhaps of the Coos group. Evidently there have been great
dislocations here.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 45

Between the Field-Tom saddle and New Zealand pond the Conway
granite prevails. After reaching the base of the upper portion of Mt.
Willey the slates are succeeded by one of the granites, and the Conway
variety seems to prevail in going to the Willey house. In passing west-
erly, on the steep south-west side of Mt. Willey, the Conway rock con-
stitutes the debris visible, with the ingredients rather finer than usual.
Following the south side of the low ridges between Mt. Willey and New
Zealand pond, the rock is altogether the ordinary Conway variety. The
high ridge east of the pond is somewhat precipitous, with no trees for
half a mile up its western side, on account of the abundance of enor-
mous blocks. About one hundred and fifty rods east of New Zealand
pond there is a small pool of water among the fragments, which is prob-
ably persistent through the year. The pond is very near the divide be-
tween the waters flowing northerly into the Ammonoosuc through the
New Zealand river, and those discharging themselves into the east
branch of the Pemigewasset. Though the pond has the name of New
Zealand, it has no connection with the stream of that designation. As
the map shows, it discharges itself through a small outlet into a consid-
erable stream flowing easterly from the south Twin mountain, and imme-
diately after their union its course changes to southerly. The notch
receiving the name of the pond and stream is broad and deep, about
2123 feet above the sea, which is lower than any part of the divide
between the east branch and the Saco. The interesting character of the
notch is well shown in Mr. Morse's sketch of the mountains northerly
from Mt. Carrigain. [See the plate in the Atlas.]

West of the pond, in following up the stream, we soon come to a wall
of granite fifty feet high, over which the water falls uninterruptedly. For
the distance of half a mile the descent of the stream is about 220 feet.
The granite is not very coarsely grained, and is succeeded on the ridge
between the New Zealand and Little rivers by a porphyritic rock de-
scribed further on.

North of Mt. Carrigain and from a short distance above the "Forks," —
the union of the Hancock and principal northern branch, — the whole of
the valley of the east branch of the Pemigewasset is occupied by the
Conway granite. This is verified by a few observations. At the falls,
less than a mile above the mouth of the stream from New Zealand pond,
VOL. II. 19

146 STRATIGKAPIIICAL GEOLOGY.

and near the north hne of Elkins's Grant, the usual variety of this for-
mation is present. Two miles above these falls, on the stream two miles
south, on a tributary, and on another branch in going from Mt. Carrigain
to Willey, the granite is made of finer materials than ordinary, and there
is much quartz present. The same is true of the rock at Nancy pond.

The mountains between Mts. Willey and Nancy are comparatively low,
falling off more than a thousand feet. This is probably due to a line of
subsidence, since the finer-grained granites and sienites occurring there
are among those usually capping the more elevated summits. We have
on hand a number of facts concerning the granites on both sides of the
Saco river, which will be presented further along, as some of them will
be amplified or otherwise modified by a special reexamination of the
valley, made in 1875.

Section from Tin to Hancock mountain. The figures for the altitudes
of this route are mentioned in the chapter on Altitudes, page 290 of Vol-
ume I. Upon Tin mountain the schists belong to the Montalban series,
with a high inclination somewhat west of north. Between the tin mine
and the village of Jackson there is a development of Albany granite. On
reaching the lowest point on the section, at Jackson falls, the rock has
changed to the Conway granite. In the bed of Ellis river there are joints
dipping at an angle of seventy or eighty degrees to the west, which are
so well marked as to resemble bedding. Others are present, also, as ap-
pears from an inspection of the heliotype in Volume I, opposite page
256. A mile or so lower down are Goodrich falls, represented in the
hehotype very finely. Mr. Vose remarks of the rock here: "The joint-
ing and quasi-bedding of the granite is very well seen from above the
bridge to below the falls. One set of joints runs east and west, and dips
steep to the north. The other set runs S. 33° W. The granite at this
place decomposes in a remarkable and instructive manner, showing the
original structure of the rock better by the decay than by the solid
ledge." [See Fig. 14.] Returning to the precise line of section, we
find the same rock extending far up the flanks of Cobb's hill. The sum-
mit of this low elevation is composed of the Albany granite. On the
west side the Conway rock returns again, and extends to the valley of
Rocky branch in Bartlett, where there is an outcrop of the Montalban
schists overlooked by us in our enumeration of the several areas occu-

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I47

I^icd by that formation. We have no observations respecting the dip of
the strata here. The occurrence of a remnant of the floor beneath the
granite in the valley reminds us of what has been said jDreviously (p.
126) concerning a similar state of things in the lower part of the valley
of Mt. Washington river.

The high ridge between Rocky branch and Razor brook shows the
Conway granite throughout, both on the surface and on the precipitous
southern slope facing Saco river. The section passes next up the east
side of Hart's mountain, and no exploration has been made there to de-
termine the precise boundary between the granite and the highly-inclined
White Mountain schists. The section now crosses one of the larger
areas of the White Mountain group, concerning which ample details
have been presented upon a previous page.

The next rock over the southerly flank of Mt. Lowell and the top of
Mt. Carrigain consists of porphyry. No outcrops show themselves for
two miles west of Duck Pond brook on the section line ; and this is the
proper horizon for the recurrence of either the Conway or Albany gran-
ites, before coming to the porphyritic series. These latter rocks are of a
reddish cast, the crystals being of a deeper shade than the homogeneous
base. Jointed planes dip towards Mt. Carrigain. The porphyries upon
the east slope of Carrigain are finer grained, more slate-like in color, and
dip at first towards Mt. Lowell. Higher up they begin to dip into the
mountain. Whether these planes are to be regarded as those of deposi-
tion, remains to be seen. On the summit of Carrigain the rock is a
peculiar speckled porphyry, reciuiring further examination for specific
description. On the west side the descent is quite steep, and the planes
constantly vary in position, as if representing numerous small folds in
the stratification. The talus is more abundant here than on the east
side, though not equal to that on the south side of Mt. Lowell.

Our delineation of this section (Fig. 15) brings in the porphyritic
gneiss at the south base of Mt. Carrigain, in the deep valley of Sawyer's
river, so as to show the mutual relations of all these formations. Mt.
Hancock on the west is composed of the ordinary Conway granite. Next
we will introduce a sketch of the rocks south of the Saco river, chiefly in
the town of Albany, as these come next in order. As a matter of con-
venience the porphyries and breccias in that area are described. There

148 STRATIGRAPMICAL GEOLOGY.

are also a few remarks about the eruptive rocks of Jackson and vicinity
upon a previous page.

Rocks .South of the Saco River.

liY J. H. HUNTINGTON.

Feldspar-porphyry and breccia. If a person Vvcre to study the rocks
of the mountain region of New Hampshire only along the travelled
roads, he would not only get an imperfect, but also a very erroneous
idea in regard to the geology of this section of the state; and there is
no one point where a person would seem to have better data from which
to draw conclusions than from the examination of the rocks along the
Saco in Bartlett, and Swift river in Albany. At a point on the Saco we
have a granite composed largely of feldspar; and at a place on Swift
river, directly opposite, we find the same kind of rock, — so it would seem
reasonable to conclude that this is the rock between these two points;
but a person who came to such a conclusion would be very much mis-
taken. Finding the granite in Bartlett, opposite the mouth of Stony
brook, we follow up that stream. Three fourths of a mile from the road,
the first outcrop of rock we find is a feldspar-porj^hyry, which is com-
posed in part at least of a triclinic feldspar. This extends probably a
mile; and the jointed structure of the rock gives to it the appearance of
stratification. This rock is followed by a breccia and porphyry; in the
latter frequently there are small crystals of a flesh-colored feldspar. The
feldspar crystals continue to become more abundant, until the rock is
hardly distinguishable from a reddish gneiss, yet a careful examination
shows that mica is wanting. Near the height of land the rock changes,
and is composed apparently of a compact feldspar, with a little quartz.
Descending from the height of land towards Swift river, joerhaps a fourth
of a mile from the summit, and on the main branch of Little Deer brook,
the rock is a distinct breccia, which is of a dark color, having a feld-
spathic paste, and pebbles of labradorite, porphyrite, quartz, and frag-
ments of schist or gneiss. About half-way from the height of land to
Swift river the rock is of much brighter colors, and contains mica, proba-
bly from fragments of gneiss. Below, there is a narrow band of a schis-
tose rock, that has itself somewhat the character of a sandstone, but so
jointed is it that it is difficult to determine the dip. This is succeeded

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I49

by a breccia; this in places passes into a homogeneous red porphyry, the
composition of which is sihca, 64.20, akimina, 8.80, iron oxide, 12.60, mag-
nesia, 2.37, Hme, 3.50, soda, 4.24, potash, 6.25. On Swift river, near the
mouth of Little Deer brook, the rock is the Albany granite.

On a ridge west of Little Deer brook, perhaps two miles north of Swift
river, there is a schistose rock similar to the narrow band found on the
brook; and then west we find the Albany granite, and the outcrops are
numerous on the west branch of Little Deer brook. East from Little
Deer brook, nearly to the Saco, except for two or three miles along Swift
river, the rock is everywhere a breccia and feldspar-porphyry. The
whole of Mote Mountain range presents a fine field for the study of these
rocks, both from the numerous outcrops that present it in so many dif-
ferent phases, and also from the fact that the forests along the whole
range have been recently almost entirely destroyed by fire. The most
southerly outcrop of this rock is in Albany, on Dry brook, near the house
of B. Farnum. Although here it is a breccia, yet there are distinct crys-
tals of feldspar and particles of vitreous quartz, making the rock more a
feldspar-porphyry than a breccia. From near Farnum's there is a foot-
path to the summit of the south peak of Mote mountain. On this path,
perhaps a mile from Swift river, the rock is composed principally of dis-
tinct fragments of schist, compact feldspar, and c^uartz. Half a mile
above this outcrop there are places where the rock is so entirely changed
that the marks of the rock as a breccia are almost obliterated, and we
have a rock, the base of which is feldspar, and in this there are orthoclase
and triclinic feldspars and quartz. Above this the rock is quite uniform,
consisting of a feldspathic base, in which there are fragments of schist,
and always crystalline particles of feldspar and quartz. This is the rock
of the south peak of Mote mountain and the ridge north until we come
to the steep ascent half a mile south of the north peak. Here the frag-
ments of schist become more frequent and more distinct. On the north
peak of Mote mountain the fragments of schist are larger and more nu-
merous than we have found them elsewhere, some of the largest frag-
ments being a foot across, and in general immediately on the summit the
fragments are less firmly cemented together than they are on the ridge
either north or south. The largest fragments are andalusite schist ; be-
sides, there are a few fragments of quartz and feldspar. The rock seems

150 STRATIGRAPIIICAL GEOLOGY.

to be made almost altogether of the andalusite schist of the White Moun-
tains. The dip of the rock on the summit of the north peak is N. 5° K.
10°, On the ridge extending north-east from the summit the rock is of
the same character as on the ridge south, except that there is a band a
mile and a half from the summit where the fragments are more rounded
than they are elsewhere, and they are smaller than they are generally on
the mountain. The breccia extends south to within a mile and a half of
Diana's Bath.

Albany granite. From the Saco in Conway, extending west along
Swift river, perhaps two miles above where the road crosses this stream,
there is a granitic rock everywhere porphyritic ; but, about a mile south
of Swift river, we find a rock of an entirely different character. This
rock, though it is not always uniform, yet in its numerous outcrops it
has the same general characteristics. It consists for the most part of a
greenish feldspar, almost black vitreous quartz, and there is sometimes a
little hornblende irregularly distributed through it. It weathers wdiitish,
and to so great a depth that no one would suspect the character of the
rock from its exterior, and it is with the greatest difficulty that unweath-
ered specimens can be obtained with an ordinary geological hammer.
At Champncy falls, which are the most picturesque of all the many falls
and cascades about the mountains, numerous walls of this rock can be
seen. Here the rock' is so cut by joints that they give to it the appear-
ance of being bedded, and near where the falls begin some of the blocks
have been moved and tilted up. The space between the blocks being
filled up, the water stills runs over them, so often the effect is very
fine. At Pitcher's falls, — called also Champney falls, — the water descends
nearly perpendicularly, except that there are three projections on which it
strikes. There is another outcrop of this rock four miles east, at Ellen's
falls, on a small stream that flows into Swift river nearly opposite Eagle
ledge. The water falls twenty feet, and it has worn an oblong cavity in
the rock twenty-five feet in length, from five to six feet in width, and
fifteen feet or more in depth, which is filled with water. This rock is
found on the east side of Chocorua, and it is also probably the rock of
the north peak of that mountain, but the rock is so weathered it can-
not be determined with certainty whether it is exactly the same or not.
The same is also the case with the rock of the summit of Passaconnaway

^

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I5I

and the high ridge south. It is true, however, in regard to both these
mountains, that the rock of their summits is composed chiefly of feld-
spar, with which there is associated a httlc hornblende. A similar rock
forms a part of the ridge extending from Passaconnaway to Chocorua.
North of Swift river. Silver Spring mountain, and also a mountain north
and one west of it, are composed of this rock. On Sv/ift river, just below
the falls, there is a rock very similar, except that it contains some quartz.
There is an outcrop also on this stream four and a half miles above
Albany interval.

Comuay granite. The area of Conway granite in Albany is not large.
In the south-east part of the town it can be seen in several places. Near
the house of S. Littlefield it seems to be undergoing rapid decomposition,
yet there are some places where it is not much changed. At Littleficld's
house the granite is cut by a trap dyke, that is not far from a hundred
feet in width. Three miles south of Swift river, towards Birch interval,
there is a typical granite, rather coarse, but the feldspar, which is of a
light color, is not stained by iron or coated by manganese. The first
outcrop of granite south of the house of N. Shackford is somewhat por-
phyritic, and the crystals of feldspar are often very large. This is sug-
gestive of the ancient porphyritic gneiss. The rock of Green's cliff and
its ridges has all the constituents of common granite, but they are so
distinctly crystallized that it very readily crumbles and falls in pieces.
Up Downs brook for two miles and a half granite is the only rock, except
a trap dyke that cuts it. In Waterville, on Sabba Day brook, there is
common granite at the falls and a mile above. j. h. h.

The Granites in Conway and the Southern Border of the
District.

There are many outcrops of the lower granite along the edge of Con-
way and Bartlett, in the neighborhood of Kiarsarge village. They are
well shown in the Artist's Falls stream, up towards Pequawket and the
Green hills. We find both these granites under Mt. Pequawket on every
side. On the east, west, and south there are specimens illustrating them
on Section VIII, and they have also been found on the north. The
Albany granite is not more than two or three hundred feet thick, but it
seems to form a sheet extending horizontally through the mountain be-
neath 2000 feet of later rocks. The relations of the underlying Conway

152 STRATIGRAPHICAL GEOLOGY.

granite, the narrow Albany variety, the slate breccias, and other rocks
composing the upper part of the mountain, are well shown by colors
upon our hcliotype of Mt. Pcquawket taken from the south.

The whole of the Green hills are of the Conway granite. On the
summit the rock is fine-grained, with jointed planes dipping north-west-
erly twenty degrees. At the west base the inclination is less. The
highest of these mountains, though 2390 feet above tide-water, seems
to be composed of the same granite with that constituting the base of
Pequawket. The top of the Conway granite on the road up Pequawket
is about goo feet, so that the slope between these two points is about
four degrees. To the south of North Conway, in the valley, ledges are
not abundant ; but the south-westerly limit of the lower granite is prob-
ably near J. Tuttle's house, where a ledge of it crops out. Pine hill may
also show a ledge of it. There are no ledges between Conway Corner
and Conway Centre, nor for a considerable distance towards Walker's
pond and Eaton. These latter ledges, when reached, arc of the underly-
ing Montalban series.

Concerning the granites in this neighborhood, Mr. Vose, in his report
of 1869, writes as follows. He did not distinguish between the three
kinds of granite occurring here.

At Chocorua, in the Swift River Valley and all along through Conway and North
Conway, we find the principal rock to be a coarse granite with little or no mica. The
same rock, or one very much like it, occurs at the southern base of P'equawket ; but
does not appear to extend higher up than four or five hundred feet above the base of
the mountain. The "Ledges" opposite North Conway, are chiefly, if not entirely, of
granite of various degrees of fineness. The vertical striped appearance of these
ledges is due to the water which runs down over them, as far as I could judge, and
does not show structure. The granitic rocks through the whole of this region are
much cut by joints, but whether any true bedding can be made out is doubtful. The
five summits cast of North Conway village, called the Green Hills, as also the "Ledges,"
and, in fact, all exposures of rock in this region, show what might perhaps be called
horizontal or nearly horizontal stratification ; but this bedding, if it is such, must not
be confounded with an apparent bedding caused by a scaling off of the rock in concen-
tric layers, from five to ten feet thick, an example of which may be seen in the upper
part of the large or south ledge (White Horse). Over the whole region fiom Jackson
to Tamworth, and far over into Maine, there is seen a well marked orographic feature
which may give a clue to the arrangement of the rocks in this district. I refer to the
general outline of the hills, which present almost universally a long gentle slope to the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 53

N. and an abrupt face to the S. The dip of the rocks, too, where this can be made
out, is ahnost always from 20° to 80^ to the North, the N. W., or the N. E.

The same granite which appears at Chocorua, in 'the Green Hills, and all along
through Conway, is found at Kiarsarge village, and in the lower part of the mountain
itself.

On the road from Conway Corner to Knowles pond in Albany, skirt-
ing the base of the mountains, we find only the Albany granite. There
is quartz in this rock on the ridge near D. Allard's. If we take the road
along the outlet of Knowles pond, we see in the south-east corner of the
town, south of the other road, a precipice of the Albany granite perhaps
400 feet high. The hill south of J. C. Kenniston's and Knowles pond is
composed of the Conway granite. This region has one peculiar topo-
graphical feature: there are several hills scattered over it, usually having
a southerly precipitous slope. This structure may be due to rock com-
position, or to the peculiar way in which granite is eroded ; but there is
scarcely any difference between those composed of the Conway, Albany,
or Concord granites. It is necessary, therefore, to visit each one to
determine its specific character. The next hill, nearly south from Ken-
niston's, on the line between Albany and Madison, and north from J.
White's, is composed of Concord granite, and is outside the limits of the
Pemigewasset series. We have no evidence of the existence of the
eruptive granites east of the railroad in Madison.

]\It. Chocoriia. One will observe an interesting order of rocks in as-
cending Mt. Chocorua. Starting with the Concord variety near Whitton
pond, we next find as thoroughly characteristic Conway granite as is ever
seen among the mountains on the hill between Whitton and Knowles
ponds, by J. C. Kenniston's. Between this and J. Piper's, whence we
commence the ascent of Chocorua, the rocks are concealed. There are
two ways of ascending from Piper's. The more usual course consists in
following the ravine a little west of north in a direct course for the peak.
On this route no rocks show themselves for a long way. The other
course is to pass due west from Piper's up the long southerly spur. This
route meets the path from J. Tasker's, north of Chocorua pond. Six
hundred feet higher than Piper's house there is a fine-grained granite,
slightly gneissic in appearance. Two hundred feet higher is the unmis-
takable Conway granite. On reaching the south end of the spur, we
VOL. II. 20

154 STRATIGRAPHICAL GEOLOGY.

find a rock different from anything that has been mentioned. In its
several varieties it occupies the whole of the Chocorua group of eleva-
tions. That first seen is much weathered, of a reddish cast, sometimes
manganesian. The feldsjDar predominates in crystalline bunches ; the
quartz is not abundant; and the black scaly mineral is apt to be horn-
blende. In other samples from this spur the quartz is abundant, and the
mica or hornblende is scanty. Similar rocks extend to the very summit.
Scarcely anywhere else is it so difficult to appreciate the normal ajapear-
ance of the rock, on account of extensive and complete weathering. In
favored localities the granite assumes a greenish color, the feldspar at
first sight resembling labradorite. A typical variety consists only of this
greenish feldspar, apparently orthoclase and amorphous smoky quartz,
very like that noticed heretofore from Lightning mountain in Strafford.
(No. 443 of Mr. Huntington's catalogue.) At the east base of the peak
there is a similar rock of greenish color, very fine-grained, prevailing to
the exclusion of everything else. These two types of rock represent our
Chocorua granite. I have called them labradorite, perhaps erroneously,
in our first volume. As they will require further study before receiving
their proper designations, I need only to speak of the behavior of the
mass in relation to the other rocks. The specimens from the north-east
base of Chocorua peak and the summits to the east are labelled as Albany
granite, though they somewhat resemble the other. This variety has not
yet been discovered on the route between Piper's and the summit of the
peak, while on the north-east it seems to take its proper place between
the Conway and Chocorua varieties. Hence our order of succession from
the starting-point seems to be, first, the Concord, second, Conway, third,
Chocorua granite. In Fig. 6i, Vol. I, one sees how the Chocorua mass
is separated topographically from everything else.

Mr. Morse's panorama from Chocorua in the Atlas shows incident-
ally the slightly inclined — 25° N. W. — jointed planes in his foreground.
Others nearly at right angles to this appear upon the summits, one in
particular of immense extent. They are prominent along the ridge for
half a mile.

This peculiar granite occupies a larger area in this neighborhood than
is elsewhere known. It occurs all the way to Ellen's falls on the north,
at three and one fourth miles west, and perhaps farther ; to the south it

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 55

occupies all of the principal spur perhaps as far as Chocorua pond. I
have not examined the area between the spur and pond as yet, and can-
not affirm from observation that these two outcrops are joined together
continuously. Specimens of it have come also from Great Hill pond,
and one mile from Bcrrv's saw-mill in the north-west part of Tamworth.
Toad mountain, about two miles north, is composed of Albany granite.
Most likely the upper rock of Mt. Whiteface corresponds with this (p.
104), though it is sienitic. Other localities of it are the north peak of
Mt. Passaconnaway, the ridge between Sabba Day and Downs brooks and
Champney falls in Albany. The principal part of Mt. Passaconnaway is
Conway granite. None of the Pemigewasset series of granites have yet
been recognized in Sandwich.

Watcrvillc, etc. Fortunately for our ease in making explorations, there
are settlements along Mad river in Waterville. This clearing reaches the
interior of the White Mountains, and thus we get glimpses of its structure
afforded by no other settlement. As one looks at the amphitheatre of
mountains from Greeley's hotel, he should understand that a considera-
ble portion of these lofty eminences is composed of the Pemigewasset
granites. On the south-west, west, and north nothing else can be seen.
Welch, Tecumseh, and Fisher are supposed to be entirely composed of
Albany granite. Osceola, at first thought to be the same, seems to be
more nearly allied to the Conway. In an extract following, by J. P. Les-
ley, mention is made of the interesting apparent bedding in this mountain.
North-easterly, the former variety appears at the lower end of the great
slide. But on the east. Snow's mountain, and the enormous Sandwich
Dome on the south, so far as known, belong to the porphyritic gneiss.
I find in the collection specimens of Albany granite from the Mad River
notch, or about the Greeley ponds, the east ridge of Osceola, and the
ridge between Mad and Swift rivers. The Conway granite occurs at
several places on Mad river below Greeley's, at the north end of the
north-east ridge of Sandwich Dome, on the east side of Snow's moun-
tain, at and above the cascades, on Flume brook a fine-grained variety,
on the ridge between Mad and Swift rivers, about a mile above the falls
on Sabba Day brook, the falls, and on Downs brook, a mile from Shack-
ford's house in Albany. The greater part of Mt. Passaconnaway has the
same composition.

156 STRATIGRAPinCAL GEOLOGY.

The rock of Mt. Osceola is to be referred to the lower division, except
the eastern spur, which is Albany granite. At the first crossing of the
west branch of Mad river by the mountain path, I have noted the pres-
ence of large blocks of porphyritic gneiss. These Vv'ill probably be found
in place there, and will explain partially why the lower granites should
exist at so great an altitude as the summit of this mountain.

A reexamination of the specimens from the lower part of the Tripyra-
mid slide, or what has been noted upon pages 38 and 39 of Volume I,
satisfies me that the rock should be referred to the porphyritic gneiss
instead of the "trachytic" or Albany granite. Hence we may accept our
first impressions of its gneissic character, and believe it to be simply an
extension of the rock on Cascade brook, perhaps including the cascades.
It may appear, also, that these ledges will connect with the loose blocks
beneath Osceola. I hope to reexamine the locality, and to present the
results of the visit in the sequel.

On the ridge between Mad and Swift rivers, up Flume brook, the
granite uniformly has a fine grain. According to our present informa-
tion, the great range from Osceola to the east branch of the Pemige-
wasset, including the Black mountain, south of the mouth of Hancock
Branch, is of the Albany variety. From Waterville across the notch
between Mts. Osceola and Tecumseh into the north part of Thornton,
and from thence to Pollard's house in Lincoln, along the v/est edge of
the granites, the Conway granite is developed, capped at Loon pond by
higher groups. These two varieties continue beyond the East Branch
in the same order, the western range passing into Franconia, and the
eastern continuing uninterruptedly beneath Mts. Flume, Liberty, Lin-
coln, and Lafayette, then passing east of the range, as the continuity is
interrupted by underlying gneisses, capping Haystack, till we are brought
to the base of the Twin mountains, or our starting-place in this descrip-
tion. There will be some further details concerning the central part of
the Pemigewasset district, over a very important line, in Section VHI.
The actual junction between the Conway granite and Montalban group
is apparent near T. C. Pollard's. The schists dip at a very high angle
westerly; the granite appears to underlie them, and there is a large
vein of it in the strata, evidently injected subsequently to their deposi-
tion and elevation. Mr. Huntington has recently found the same granite

:n Pollard's to the top of the so
uixiice in height between the two poini

he fTiLinite mass is uot less than this fiLr

Franconia ■ region.
granites and prrnh'''r,
of Mt. Libert}
this sect;- '
The Cor

1 tie discovery ot the proper siiccessi

I.i^rol!

ul

section from the

: - ::. •: . . OUC Oi thcj UiU.it littOCUVc ^r.:;^-A-. -Yi Uc liClgllbOfi

i:, ;. ciia'-iii xcavated out of the Cor'v-f?v p:ranitc, three or four

feet long, twelve to twenty fe-

is east and west. Our heliotyp ■

the right hand are the natural vs-^<]

these rocks all over the raour'..

horizontal, which illustnn^ '

possibly corresponding ^

high. Its course

:; i.cii Ku-i i;i its character. On
joints which cut vertically across
re fainter lines nearly
.>i another set of joints
ition. In the distance
light between tlvc
- slight !>-<;-:

wiicruuii

exhibiteci

feet wide, or across

lower part may be rwervc -t

lookinc^ vn from the nb.tfor'

. onsistmg of

u-iik iuv_iv common to this

both v»crhai)s Luvntv-fnin

158 STRATIGRAPIIICAL GEOLOGY.

to thirty inclics wide. The occurrence of this dyke at once explains the
origin of the chasm. The running water wears away the hght-colored
trap. Then water, percolating the vertical joints back of the eroded
space, freezes in the cold weather, and, by the consequent expansion,
pushes a mass of rock inwardly till it falls into the stream. During the
warmer months the water is busily engaged in pulverizing the boulders,
assisted by chemical reagents, or the removal of the potash of the feld-
spar by solution. As soon as there is space for the further action of
freezing in the joints, other masses of granite are overthrown and worn
away, till Nature has succeeded in manufacturing the completed flume.
In the heliotype one sees on the right the remnants of some of the ver-
tical sheets not entirely broken down. It is likely that the regularity or
parallelism of the walls has been perfected by the action of the dyke
upon the rock when in the formative condition.

The Pool is a circular excavation in the same granite, about one hun-
dred and fifty feet in diameter, and forty deep. It is supposed that it has
been excavated by the action of the Pemigewasset river, just as is the
case with the Basin, — a pot-hole about twenty-five feet in diameter, situ-
ated midway between the Flume and Profile houses, by the side of the
carriage-road. It is figured on the same plate with the Flume boulders.
The rock is the same as in the Plume ; but the Franconia breccia under-
lies it just above the junction appearing in the view.

Very large exposures of the Conway granite show themselves in con-
nection with cascades on the stream from the west just below the liasin.
This granite shows orthoclasc and oligoclase. It extends southerly, cap-
ping Mt. Pemigewasset, this being its farthest development in that direc-
tion. At Tamarack pond and over Profile mountain the same feldspar,
with quartz and mica, are present ; but the materials will not average
more than the tenth part of their lengths in the coarser rock. The
north-west spur of Profile mountain, towards Franconia, is clearly a gran-
itic cone, probably like that of the principal part of the mass. The Pro-
file is made of similar materials, in a decomposed state. These ledges
often approximate to the porphyritic structure. The planes dip west of
north near the Profile house. Trap and porphyry dykes occur on the
same side. On the eastern summit of Profile the planes dip S. 35° E.
The highest part of the mountain, to the west of the location usually

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 59

visited, exhibits planes dipping io° westerly. Though the rock is firmer
than ordinary, we have mapped all this region as connected with the
Conway division.

If one takes the short cut to Tamarack pond, from where the old
bridle-path leaves the main road for Mt. Lafayette, on the town line be-
tween Franconia and Lincoln, on the west side of the valley where he
begins to climb, he will find an excellent granite for building purposes,
having a lively color, and not liable to crumble. It contains chlorite and
the two usual feldspars. A similar rock, but coarser, crops out near the
Fish house. At another location on the road-side, a mile or two below
the Profile house, there may be seen a crumbling ledge of Conway gran-
ite, with both vertical and horizontal joints, and it shows a tendency to
decompose along the seams, presenting slightly the aspect of a mass of
spherical bodies closely packed together. On the west side of the valley
one sees a precipice where the jointed planes are spheroidal, and rudely
parallel to the vertical wall of the cliff. At the base of the precipice
are large piles of debris. This is on the east wall of Profile mountain,
and the southern continuation of the famous Profile. A view of it ap-
pears on the same page with the heliotype of Eagle Cliff range from the
south.

Walker's stair-case or falls exhibits finely the jointed planes slightly
inclined westerly. [See vol. i, p. 305.] Both the Conway and Albany
granites appear on this stream ; but the texture is finer than ordinary, so
that it is difificult to draw the line plainly between them. As ledges of
porphyritic gneiss occur considerably higher up, it would appear that
there existed here a deep valley, into which the granites flowed, not fill-
ing up the depression to the brim, unless there have been extensive ero-
sions since.

We find quite near the top of the Lafayette range, close to the porphy-
ries, a considerable area of the Albany granite, resting upon porphyritic
gneiss or the Franconia breccia. This sheet seems to connect with that
already spoken of as underlying Mts. Liberty and Flume. We have not
yet found the Conway granite in contact with the Albany north of Mt.
Liberty, at the higher level, though there are immense tracts on the
western slope of such difficult interpenetration that their exploration has
been neglected. The resting of a hornblendic variety of granite upon

l60 STRATIGRAPHICAL GEOLOGY.

the porphyritic gneiss, disposed in nearly horizontal plates, near Walker's
falls, has been noted upon page loi. We have got glimpses, besides, of
Montalban schists, the Franconia breccia, and labradorite rocks along this
same range or uplift of older rocks, between the valley granites and those
high up the flank of the Lafayette range. The finer Conway granite, like
that of Mt. Profile, crops out on the bridle-path up Lafayette, midway
between the south Franconia line and the Lakes of the Clouds.

Between Mts. Lafayette and Haystack there are three elevations, whose
character may be conveniently mentioned here. Lafayette itself is com-
posed of porphyry at the very summit. The long north-westerly spur
from it has the same character. The first eminence towards Haystack
is composed of gneiss connected v/ith the Franconia breccia. Specimens
of granular quartz illustrate the second. The third is composed of Beth-
lehem gneiss. Haystack itself seems to belong to the Albany granite
layer. Specimens from these summits were collected for us by Messrs.
Smith, Hoitt, and Conant, of the Dartmouth party of 1871; and the trips
taken to find them were very laborious. It is supposed that the Albany
granite is continuous from Haystack to the north slope of Twin moun-
tains, but this theory has not been verified by actual perambulation.

Mr. Huntington having climbed Mt. Lafayette since the above was
put in type, communicates his impressions of what he saw, in the follow-
mg letter:

The first outcrop of rock on the bridle-path above Eagle Cliff is perhaps three fourths
of the distance from the Cliff to the summit of the ridge west of the Lake of the Clouds.
It is a narrow band of the spotted (Albany?) granite. On the summit of the ridge the
rock is porphyritic gneiss, the dip of which is probably south 60°. Whether it is the
same as the gneiss in the central part of the state is a question, since you will remem-
ber that portions of the rock that makes up the breccia are also porphyritic. Just
above the Lake of the Clouds there are a very few crystals of feldspar ; and the rock
resembles that of a portion of the breccia. Above the rock is a breccia, or, if it is a
gneiss, there are concretions in it. There is little doubt that it is a breccia, however.
The rock succeeding this looks more like a gneiss, and dips almost directly east. We
then have a fine- and coarse-grained granite, then the spotted (Albany .'') granite, and,
last, the porphyrite, that forms the summit of the mountain. On the lowest part of
the ridge, towards the south peak, the spotted granite outcrops; but on all the liigher
points, including south peak, the rock is porphyrite. I did not see any rock that I
could call labradorite, though even in the spotted granite some of the crystals of feld-
spar appear to be labradorite.

. GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. l6l

It would be properly in order next to take up the laijradorite rocks,
and the porphyries occupying the area inclosed l^y the granites just de-
scribed. Inasmuch as a little more investigation is required for their
satisfactory description, I will depart from the established order, and
present next a full account of the rocks recently dispb^yed by cuttings
along the Portland & Ogdensburg Railroad, in the White Mountain
Notch, followed by abundant citations from the best authors who have
written anything concerning the geology of the White Mountains.

The Rocrs in the \yiriTE Mountain Notch.

I propose now to describe carefully the outcrops of all the formations,
mostty not alluded to before, cropping out along the route of the new
railroad between Fabyan's and Bern is station, vvdth any new information
I may happen to have about the adjacent mountains. The slates of this
region have not yet been described, and I shall therefore anticipate that
part of the chapter. The following sketch is mostly the result of obser-
vations made in July, 1875, undertaken for the purpose of testing the
value of theories suggested in the earlier part of this report. There is a
somewhat triangular area occupying the Ammonoosuc valley first requir-
ing attention. It is bounded east and south-east by the range of presiden-
tial summits, which are all of the Montalban series ; west, by the Field-Tom
line of elevations, extending to the Ammonoosuc river, and north by the
Cherry-Deception-Dartmouth group. The land is everywhere compara-
tively flat, as compared with the mountainous border. The difference is
excellently set forth in the heliotype showing the Mt. Washington range
from the Fabyan turnpike. Volume I, p. 392. Two sorts of granite
occupy the whole of this low country. The first is much like that of
Concord, well seen along Section IX. It is tender, friable, with a nearly
uniform texture. The second shows crystals of feldspar, porphyritic and
extensively elongated. Its most conspicuous localities lie along the east
border of the valley from Mt. Dartmouth across to the base of Pleasant.
It protrudes through beds of the Montalban schists at the base of Mt.
Pleasant, as well as constituting an extensive area by itself. This fact,
however, shows its age. This area is probably continuous westerly
across to the Portland & Ogdensburg Railroad, a mile north of the
Crawford house, where it crops out in a small stream. Between the
VOL. 11. 21

1 62 STKATIGRAPHICAL GEOLOGY.

Crawford and Fabyan houses, along the raih'oad, there are numerous
exposures of one or the other of these two granites. They do not extend
far up the side of the range to the west, where they join the Conway
granite, for the whole way. Other facts concerning this area are stated
upon page 137.

Concerning the streams flowing westerly from the main range of presi-
dential summits, it may be proper to mention, that, as very few of them
are distinguished by any appellation, I have designated them by the name
of the mountain they spring from, both upon the map and in our descrip-
tions. The well-established name is Ammonoosuc, which starts from
the Lakes of the Clouds. Then we have Monroe, Franklin, and Pleasant
brooks. The Ammonoosuc passes the station, giving it a name. Monroe
crosses the turnpike a short distance west of the station. Franklin and
Pleasant unite quite far up. We have also used the name of Jefferson
brook for the second stream north of the mountain railway.

Mt. Tom and Cascade brook. Passing up Cascade brook for about three
fourths of a mile, there is a foot-path designed for observing Beecher's
cascade ; and at the upper end a fine view may be obtained of Mts.
Pleasant, Monroe, and Washington. For this distance we conceive the
rocks belong to the Montalban series. It is very granitic, penetrated by
several systems of joints. Silica is abundant, seemingly finely diffused
through the mass. The rock partakes somewhat of the character of that
excavated for the railroad at the Notch, but more of that in the Ammo-
noosuc plain, just noticed. Of the nearly vertical seams we find low down
the courses east and west, north and south, north-west and south-east, as
well as north-east and south-west. These predominate in the lower se-
ries of falls. The main fall, figured in Volume I, page 305, exhibits the
north-easterly course, the stream having worn a deep, flume-like passage
for itself out of the granite. A more remarkable set of joints begin
to display themselves above the principal cascade, dipping easterly from
five to twelve degrees. They seem to exist in greater perfection the
further we ascend from the Crawford house. The first ledges seen have
been excavated irregularly; and numerous narrow branching granite
veins ramify in various directions, though notably in the same direction
with the stream. There is also a dyke of trap two or three feet wide,
with a course east of north. The u^oper seat marks nearly the western

GliOLOGY OF THE WHITE MOUNTAIN DISTRICT. 163

limit of the Montalban group, and it may be from three fourths to seven
eights of a mile west from the Crawford house, by estimate, and perhaps
several hundred feet of elevation.

Nearly a quarter of a mile beyond, a granite allied to the Conway
shows itself, with the prevailing numerous joints dipping a few degrees
easterly. The constituent minerals resemble those of the rock just
passed over, but are considerably larger. All the outcrops for at least
three fourths of a mile are of this character. At the lower end of an
unusually broad opening it is very ferruginous; the joints are inclined
less than five degrees, and the grain is more like that of the first rock.
It is just above this that the north side is bare of trees ; and in the val-
ley there is a great abundance of a vermilion vegetable coating spread
over the boulders and ledges. The lower exposures are of great impor-
tance, because the granite contains many fragments of the hard Mont-
alban schists, sometimes from twelve to fourteen feet long. Several of
them seem to carry andalusite quite abundantly. It is not clear whether
these fragments are distinctly Montalban, or whether they agree with
the dark slates found higher up the mountain, and also back of Mt. Wil-
lard. They would be clearly ranked with the first, unless the metamor-
phic influences of the granitic paste have altered the character of the
upper slate. This is the only example yet discovered which seems to
intimate the possible origin of the Conway granite as later than the
deposition of the dark andalusite slates. In a similar brecciated mass
by the side of the railroad, under Mt. Willard, the fragments are en-
tirely of the lower schists ; and the imbedding granite more nearly
resembles the Albany, while the Conway is adjacent. Upon Cascade
brook the cementing granite is more abundant than in the latter locality.
In both cases, one can recognize near each other fragments of the same
mass.

Higher up this stream there is a great abundance of the Conway
granite, with its usual features. At about two and a quarter miles, by
estimate, there seems to be a limited outcrop of a spotted granite, por-
phyritic by numerous crystals of orthoclase, in contact with slate. A
similar contact will be described upon the south side of Mt. Willard,
further on. As no ledges show themselves for a considerable distance
below the line of junction, we have no data for determining the width of

164 STRATIGKAPIIICAL GEOLOGY.

the spotted granite. Both to the north and south of the stream, it forms
a comparatively broad belt. The slates first seen are somewhat indu-
rated, and dip 55° N. 62° W. A little higher they stand on their edges,
and presently the dip is 55° N. 80'' W. Here we left the valley and
climbed up a steep slope, bare of vegetation, because removed by pow-
erful currents of v/ater in the time of freshets. Ledges of slate, having
about the same position with those just described, occur frequently at the
steeper part of this ascent. More particularly, about one hundred and
eighty feet up, the rock is an argillaceous quartzite, dipping 75° W. It
is well exposed for several hu.ndred feet vertically with the same position.
Above that it is less siliceous and more argillaceous, and slightly wrinkled.
The dip is often 70° or more, and again 60° N. 82° W. At various places
below and above we found slates rusty from an external ferruginous coat-
ing, with the interior whitish. The top of Mt. Tom is broad; and you
may travel a considerable distance over a slightly inclined surface, where
the trees are a foot or more in diameter, even to the very summit. At
the saddle, between Tom and Field, the spotted granite is in place, but at
the highest point the rock is a feldspathic indurated slate.

I have descended the mountain easterly three times, by somewhat
different routes. The rusty, felsitic slates, first seen in going down,
become white when broken. Passing northerly we meet with large
blocks of spotted granite, not certainly in place, but it has little thick-
ness, and then we find ordinary argillo-mica slates ; and, under them,
others charged with andalusite. The dip is very high in the direction
N. 82° W.

A matter of interest may be seen on top of a north-easterly spur of
the mountain which lies upon the east side of a stream flowing northerly
at first, and joining the south branch of the Ammonoosuc about two
miles below the Fabyan house. The rock is a black slate, crowded with
pencils of white andalusite, being the same layer with that yielding the
numerous boulders of this nature so conspicuous in the streams. The
dip is 60° N. 72° W. If this knob deserves a name, it should be called
Mt. Andalusite, after the beautiful crystals first found here by Messrs.
Abbott and Bacheler, lost sight of for some time, and then rediscovered
in 1873. The position all over it is essentially as just indicated. We
found the same rock to the south-east, trending towards Cascade brook.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 165

It docs not appear there, because so completely covered by drift. Ec-
low this slate we found an interesting slate breccia, like that on Mt. Wil-
lard, with a westerly dip. Under this and the slates, in proceeding
easterly, we found a great thickness of the spotted granite in ledges.
Beneath this is upwards of a mile breadth of the Conway granite. But
I suppose the first small eminence north of Cascade brook, at the very
foot of Mt. Tom, and adjacent to the Crawford house, is made up of the
harder Montalban granites. On another line of descent, not more than
a mile north of that just mentioned, the same order of granites was ob-
served below the slates.

A trip was taken to the north of Mt. Andalusite to determine more
carefully the relations of the slates and granites, as well as to search for
a compact variety of the spotted or Albany rock, so nearly resembling
labradorite as to have been originally mistaken for it. The first rock
north of the slate proved to be the Albany, which we followed for a
mile or so, with planes dipping north-easterly four or five degrees. This
continued for about three hundred feet down the easterly slope, where
the Conway granite was encountered, and may be one thousand feet
thick. The peaks to the north of this, as far as the lower falls of the
Ammonoosuc, near the White Mountain house, are entirely composed of
the Conway granite.

Mt. Willard. Mt. Willard is a small mountain situated directly in the
water-shed between the Saco and Ammonoosuc basins, to the west of
the Notch. In the heliotype op^^osite page 79, Volume I, the view from
the Crawford house, it may be seen rising up from the Notch on the
right. It is 926 feet above the Crawford house, by a recent aneroid
measurement. The northern slope is not steep, and has over it a great
thickness of glacial drift, upon which large trees grow abundantly. On
the south side is a bare precipice of a thousand feet depth, one of the
largest seen about the mountains. A carriage-road winds to the summit ;
and the view of the Notch below is exquisite, though poorly represented
opposite page 625, Volume I. Since that drawing was prepared, a very
conspicuous line has been cut out around the west side of the valley,
high up, marking the position of the Portland & Ogdensburg Railroad.
The excavations on the steep side of Mt. Willard and farther south, for
the benefit of this railroad, enable us to speak of the rocks along the

l66 STRATIGRAPHICAL GEOLOGY.

Saco valley with more precision than usual. At the end of the road on
the summit the rock is the Conway granite, with joints running in vari-
ous directions. To the east, the line of junction between the granite and
hard gneisses may be observed about five or six hundred feet distant, at
the south-east angle of the cliff. On passing to the base of the first cliff,
one can readily distinguish this line of junction, with a north-west course,,
and vertical. On looking down the steep, impassable slope, the schists
seem to come to a point in the granite one or two hundred feet distant.
In the granite above there are joints parallel with the line of union,
seen especially where the cliff overhangs about twenty feet. The most
northern point where I have seen the granite must be about six hundred
feet north from the summit, near the line cut from the carriage-road
to the new flume. To the west, perhaps two or three hundred feet of
surface is occupied by the Conway variety. The principal part of the
cliff is composed of this rock, and it may be followed down across the
railroad to the upper bridge over the Saco, in the carriage-road down
the Notch. The railroad runs over this rock about seventy rods. The
vertical thickness, from the Saco to the top of Mt. Willard, is at least
1800 feet, which represents the vertical dimensions of the granite. It
is supposed to be continuous southward along the west base of Mt.
Webster, Along the railroad it disappears, passing beneath the spotted
granite and the slates, coming up about a quarter of a mile south of
Willey brook, as if it constituted a synclinal axis.

Alo7ig the Railroad. Starting from the Crawford House station, we
proceed 1900 feet before coming to the first cut in the rock, 200 feet
long. This interval represents an extensive accumulation of detritus
brought down from the adjacent mountains by the Ammonoosuc branch,
Cascade brook, Gibbs brook, and others of smaller size. The ledges we
suppose fall off to the north very much as they do towards the Willey
house, and would therefore be more than one hundred feet below the
Crawford house. On the north side of Elephant's Head is a ledge of
gneiss resembling the Concord granite, with jointed planes, possibly
strata, dipping N. 87° W. The stone has been quarried somewhat for
piers and abutments. The rock in the first cut lies beyond this granite,
and is a hard gneiss, breaking with difflculty into angular pieces, with the
dip of S. 63" W. 75°, It is cut by several large and coarse granitic veins,

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 16/

holding black tourmaline, small garnets, a greenish mineral not yet deter-
mined, apparently a hydrous-mica, occurring in thick lamellre, albite, and
others. Some of these veins are three feet thick. A few layers concen-
trate a bronze-colored mica ; others consist of what seems at first a hard
granite, lacking mica, which is the most characteristic rock throughout
the Notch, and is called a granite on p. 123. It so intermingles with
what is surely stratified that it cannot be separated from gneiss. So
compact are its constituents that they seem as if cemented by an infil-
trated silica. Other layers, partly decomposed, show a reddish color
from the oxidation of iron and white spots of feldspar.

The second is a much larger cut than the first, being 450 feet in
length and three times as deep as the first. The rocks are the same
with those just described, but the veins are larger, more numerous, and
somewhat diversified. They contain all the minerals first named, also
fluorite, galenite, smoky and transparent quartz crystals, pyrite, pyrrhotite,
calcite, siderite or ankerite, and an unknown green mineral. The fluorite
is both pink and green. The iron-carbonate has completely oxidized, and
the crystals crumble to powder upon exposure, leaving behind abundant
bunches of " paint." In other parts of the cut a little copper pyrites and
green tourmalines occur. Among the fragments in the pile to the south,
I find bunches of chlorite. There is no regularity in the strata or joints
in this cut. The vein holding fluorite and quartz crystals runs north and
south. The most marked planes that have any resemblance to strata
dip S. 78° W. Other veins cross the supposed strata irregularly. So
numerous are these veins that Professor Dana, who examined the rocks
of this neighborhood with me, suggested they might indicate the pres-
ence of an anticlinal axis at this point. Possibly the dip corresponding
to this, so as to make the arch, may be the one to N. 57° E. yG" , above
Silver cascade, p. 123, though opposing inclinations are not needed to
prove the axis in a region full of inverted folds.

After passing the trestle-work, there is a third excavation known as the
"James cut," 250 feet long. This is through the more granitic variety of
the hard schist common at the two other cuts. Near its southern termina-
tion there is an apparent dip of 70° S. 70° W. A possible dip of 75° N.
38° E. is spoken of here. These planes may perhaps be connected with
the course of an interesting trap dyke, having the same strike, or N. 52° W.,

1 68 STRATIGRAPHICAL GEOLOGY.

and dip. This dyke may be five or six feet wide, and is supposed to cut
both the hard schists and the Breccia granite just below, towards Dismal
Pool. As seen from the carriage-road at its western curve, this James
ledge is full of reticulating granite veins, some two or three feet wide.
The strongest run north-westerly, but at three places one can see them
cut and shifted by smaller veins crossing nearly at right angles and other-
wise. With the sun shining upon their blanched surfaces, they are very
conspicuous. They also occur upon the hard ledges inside of the west-
erly projection of the road.

Immediately below the cutting there is developed an extraordinary vein
or mass of granite, w^hose presence has led to the discovery of additional
interesting features in the geology of the Notch. The junction is now
concealed by the abutments just below the James cut, where it was dis-
played to the best advantage in fresh excavations. The phenomenon is,
briefly, a vein of slightly poi-phyritic (allied to the Albany) granite, 450
feet thick, dipping under the hard Montalban schists somewhat east of
north, the latter supposed to have a strike either N. 20° W., or N. 52° W.
As seen from below, the mass of schist has a slope of perhaps 15° from
the top of Mt. Willard to the James cut, underlaid by this bed of granite.
Both masses are cpiite conspicuous, and the line of junction, having the
direction N, 18° E., may be followed up past the flume, where the com-
mon strike of the schist is N. 27"" W., the dip being vertical. Near the
southern point of the schist the position is very nearly the same, the
strike being N. 22° W. At the head of the south or Butterwort flume,
the strike is N. 32° W. Hence the evidence is clear that this mass of
granite fills a chasm, passing scjuarely across the Montalban strata. Were
the granite a stratified formation, the relations of the two to each other
would be described as unconformable. The granite itself when fresh
shows a predominance of orthoclase in large crystals of half an inch or
so in length, and smaller rounded (sometimes crystalline) masses of
quartz scattered through a fine-grained granitic aggregate. The mica
may often be in black patches, large enough to be conspicuous, though
usually in very small bits. A finer grained variety of this rock occurs
near its junction, but is not abundant. As usually seen, this granite
has a reddish aspect from weathering ; and it has a close resemblance
to many ledges referred to the Albany series elsewhere among the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 69

mountains. The lower junction of this granite with the IVIontalban is
concealed by drift, but the strata of the latter are distinct, standing ver-
tical, with the strike N. 42° W. They are better characterized than those
above, though they do not extend more than 1 200 feet before a change
ensues.

The fact of greatest importance in regard to the granite remains to be
mentioned. Following the railroad to where it would naturally be inter-
sected by the Butterwort dyke, or 4700 feet from the Crawford station,
we come to a breccia of enormous pieces, five or six feet long, and less,
the fragments consisting entirely of the hard Montalban schists, while
the cement is of the variety of granite just mentioned. One can see
that it has found its way between large pieces that naturally fit together.
This breccia extends for 1200 feet along the railway, but it does not appear
much higher on the mountain. Between it and the exposure of schists
at the summit only granites appear. Something of a breccia character
in the Montalban schists has already been mentioned in the description
of the upper part of Mt. Washington river ; and at the Notch cuttings,
imbedded pieces of the schist in the granitic portions are not rare. It
forcibly reminds us, however, of the Franconia breccia, thought to
mark the close of the Montalban period ; and we have recently described
also masses of the same rocks imbedded in the Conway granite above
Beecher's cascades. As a matter of convenience, I propose to call this
cementing material the Bi'eccia granite, to distinguish it from the many
other varieties of this rock in the White Mountains.

The next rock seen along the railway is the well-known Conway gran-
ite, already mentioned as constituting the summit of Mt. Willard, and fol-
lowing up the valley of the Saco to about the 1 500 feet contour line. It
occurs along the railroad for 1 300 feet, and makes up the greater part of
the south precipitous exposure of the mountain. Its features are pre-
cisely the same as if it occurred in Conway or Franconia. On one large
ledge the crystals of quartz seemed uncommonly abundant. Its union
with the spotted granite, as well as the boundaries of the slaty breccia
and slate along the railroad, are obscured by drift.

Along the Ca7'riage-road in the Notch, etc. The beginning of the
original Notch, before railroad excavations cut into it, appears in the
heliotype opposite p. 79, Vol. I. The rock is the same with that de-
VOL. II. 22

I/O STKATIGRAPHICAL GEOLOGY.

scribed in the first and second cuttings. Tlic dips cannot be discerned
so easily as in the cuttings, on account of weathering. In the original
Notch there is only just room enough for the small Saco river and the
carriage-road. The most prominent joints have the courses N. 58° E.
and N. 32^ W., being vertical, and dipping 70° easterly. Another runs
north-easterly. By their intersection the rock is cut into quadran-
gular blocks of large size, sometimes isolated by the denudation of the
surrounding mass. Such is the " Pulpit." On the east side of the road
one sees also small valleys, made by the enlargement of the jointed planes
through erosion of softer seams, sometimes veins or dykes. Other irreg-
ularities are fancied by tourists to be the profiles of the " Young Man,"
" Old Maid," " Baby," etc., — which resemblances are not striking. Over
against the lower part of the second railroad cut is a great mass of the
schist cut into blocks by N. E. and N. 36° W. joints. There is also a
south-west flume-like excavation, six or eight feet wide, separating another
smaller mass of schists from the first, through which the Saco may run
at times, there being another course nearer the road. The northern side
is fifty and the southern thirty feet above the stream. Following it
around nearly to the south end of the railroad cut, one will find a cave in
the hard rock, produced by the enlargement of one of the jointed seams.
Very soon the road overlooks the Dismal pool, an expansion of the Saco,
rendered larger of late by the fragments of rock thrown down by blast-
ing. This is 225 feet lower than the track at the James cut, and not
quite so far beneath the road. A little farther south, where the road
makes its greatest amount of westing, the hard schists may dip north-
easterly. This curve in the road is occasioned by the occurrence of a
spur of hard rock on the east. At some distance below we pass in suc-
cession the Flume and Silver cascades.

Next, our attention may be directed to the distribution of the Breccia
granite. It was said to dip somewhat east of north along the railroad.
Coming down to the mouth of Dismal pool, the high cliff seen to the
east, connected with the most western angle of the road, is composed of
the usual hard schists, traversed by numerous veins of coarse granite.
The Breccia granite dips under it in the direction N. 58° E., only the
upper part of it showing. From thence it may be traced south-easterly to
the Silver cascade, crossing the road about by the Flume cascade, or a

T'x^y^ IX.

^:.i¥r A l^b' A,.iv' —^ 5^c h'^'^I- s;

-o^^^-. jr

Tig. 16. Yi^^^r o£ Mt.Willard feowL Silrer CascaS^.

Tig. 14. EeJiuiins of Structure 121 Granite at Goodrich Tails.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I /I

little lower. On ascending the Silver cascade, the first thirty or forty
yards from the road consist of the hard granitic schists. Next follows
perhaps 300 feet thickness of Breccia granite rather more siliceous than
common, reaching to the top of the falls as shown in the heliotype, while
the same Montalban gneisses appear behind where the water has worn
through them. The color of the foreground represents the hard Mont-
alban schist ; the upper is the new variety of rock. The under slope
of the Breccia granite at the falls dips 60° S. 48° W. The gently dipping
planes, 15° S. 17° W., are in this rock. The harder variety does not seem
so well adapted to be permeated by them. The rocks above are noticed
on p. 123. From this point I have traced this granite along the hill-side
to the middle and upper parts of Mt. Webster. Between the cascade and
first outcrop of Conway granite the Montalban schists prevail, perhaps
a distance of sixty or eighty rods.

I desire to present here a rough sketch of the appearance of the several
kinds of rocks on the east side of Mt. Willard, as seen from a short dis-
tance above the road at the falls on Silver cascade. It is given in Fig. 16.
The view extends from the south cliff of Mt. Willard, a little above the
north flume. On the left the limits of the Conway granite are defined.
The Montalban schists extend thence past both flumes down to the
James cut, beyond the limits of the figure. The cliff under the Butter-
wort flume is thought to be the brecciated part of the Montalban
schists, which attain here their highest elevation. To the left is a smooth
face of the Breccia granite, dipping gently northerly. Below, the bushes
and debris conceal the exposures as far down as the railroad. From a
point farther south on Mt. Webster the whole length of the Butterwort
flume is finely displayed. From the last point of the hard schists on the
carriage-road to the southern termination of the same schist on top of
Mt. Willard, the course is about N. 75° W.

Flumes. During our examination of the upper part of Mt. Willard
two interesting flumes were discovered. Starting from the top and fol-
lowing round the edge of the cliff, we soon pass the junction of the
Conway granite with the hard Montalban gneisses. The first flume is
only a short distance beyond. It is not perceptible from the top of the
cliff. Its course is determined by a trap dyke dipping 65° S. 10° W.,
about five feet wide. For about 200 feet the excavation into the moun-

172 STRATIGRAPIIICAL GEOLOGY. .

tain may average a depth of twenty feet, and the inclination of the floor
is too steep to allow one to descend or ascend in it. The schists on the
south stand on their edges, with the strike N. 20° W. The dyke has
caused the formation of joints parallel to itself in the schists, almost to
be confounded with strata. In this flume I found, growing rather spar-
ingly, a beautiful flower, the Piugiiicula vulgaris, or Butterwort. It is
said to range from " western New York to Lake Superior and northward."
None of the botanists who have explored the White Mountains for plants
speak of it; so it must have escaped their notice. In memory of this
plant, therefore, I will call the chasm the " Butterwort flume," to dis-
tinguish it from the one farther north. As one stands on the slope of
Mt. Webster, or even at the bottom of the steep hill in the Notch, and
looks up Mt, Willard, he can see this iiume extending downwards for
perhaps 500 feet of vertical descent, or pointing directly towards a black-
smith shop on the railroad, about 3000 feet north of the Willey brook.

North of the Butterwort flume the hard schists have the strike N. 30°
W., and a disposition to dip S. 60° W., scarcely less than vertical. Pres-
ently we come to another and larger flume, estimated to be 1000 or 1200
feet from the top of Mt. Willard. The rock has the strike N. 27° W.,
with vertical strata. Looking east one sees a narrow chasm with the
course N. 68° E., curving presently a little more northerly, and seeming
to point to the Silver cascade on the east side of the valley. After
travelling through the flume, I made the following estimates of its size.
It is 350 feet long, seven feet wide at the top, varying to six, ten, five,
and finally eight feet. It is everywhere widest at the top. The walls are
generally vertical, the south wall occasionally hanging slightly over a
perpendicular. I judge that portions of this wall rise 100 feet above the
floor ; usually they will not exceed half this amount. The top rises 220
feet above the lower opening, the latter being 580 feet above the railroad
beneath. The place is evidently one of interest to tourists, and the pro-
prietors of the Crawford house have already cut a path to it, and propose
to add a rustic bridge, so that its beauties may be better appreciated.
Doubtless many persons have noticed a cleft in the upper edge of the
mountain, when looking in that direction from the bridge at the base of
the Silver cascade : that is this new flume.

It may be proper here to state that this dyke may once have been con-

-m

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 73

tinuoiis from Mt. Willard across the valley to Mt. Webster, through the
flume and cascade, at the level of the higher land. At the time of the
ejection of the trap, the liquid would have flowed out at the bottom of
the valley and not have reached the summits of the mountains, unless
the whole space between were filled up to the brim ; therefore the ledge
must have been continuous from summit to summit. It would seem to
follow in like manner, from the occurrence of numerous dykes in Mt.
Webster, that the whole of the Notch valley was once filled with solid
rock. The immense depth of this remarkable gorge, from the Gate to
Sawyer's rock, has all been excavated out of solid material by aqueous
and glacial agencies, acting constantly since the beginning of Paleozoic
time. Possibly its course may have been determined by fractures induced
during the folding of the strata. Essentially this view of the origin of
the Notch, especially the use of trap dykes to prove an immense erosion,
was suggested by Prof. O. P. Hubbard, in a memoir from which extracts
will be presented shortly.

Below this northern flume there are about 120 feet of hard schists,
and then for the rest of the way to the railroad the Breccia granite is
exposed in a smooth precipitous slope, almost impassable. Paths could
easily be made along this eastern wall of the mountain, that would be
very attractive to tourists. If they are slightly dangerous the course
will be the more eagerly traversed.

NortJi-zvcst side of Mt. Webster. A further examination of the north-
west side of Mt. Webster has enabled us to profit by our knowledge of
the exposures along the railroad. It will be remembered that the Breccia
granite starts near the Butterwort flume, and gradually descends the wall
of Mt. Willard to the James cut, thence to the outlet of Dismal pool,
whence it changes its course and begins to pass up the east side of the
valley, crossing Silver cascade a hundred feet east of the road. It con-
tinues from thence to the most considerable cliff on the west side of Mt.
Webster, figured in our heliotype, p. 79, Vol. I. At this point it has
about the altitude of Mt. Willard, and is estimated to be 300 feet thick.
As near as I can judge, its course is not in a right line, on account of
various shiftings of the rock not fully understood. The general course
is from near the top of the Willard cliff to Dismal pool, thence up the
west side of Webster to the greatest precipice, and perhaps farther.

174 STRATIGRAPHICAL GEOLOGY.

Were the valley full of rock, as has been supposed to account for the
trap dykes, this vein would have a northerly inclination of ten or twelve
degrees. In fact, it proves denudation just as well as the dykes.

A trip up this ragged edge of Webster starts from the Conway granite
in the valley. Thence, over an interminably long slope of debris, we come
to the base of the large cliff more than a hundred feet high. Upon ex-
amination it proves to be composed of several kinds of rock. At the
north end of its summit the Montalban schists occur with the strike
N. i6^ E. These are traversed by segregated veins of granite twenty or
thirty feet v.-ide, analogous to those in the first cuttings in the Notch.
Next to this is two hundred feet width of Breccia granite, the line of
junction being N. 68° E., at right angles to the edge of the cliff, and
the rocks meet with vertical faces towards each other, pointing into the
mountain. At the southern edge of this precipice are more of the hard
schists, followed by Conway granite, supposed to extend southerly from
this point for miles uninterruptedly. Lower down the precipice are
towers or quadrangular pinnacles of the hard schists, precisely like the
Pulpit in the Notch. The Conway granite is supposed to extend also
from the road to the base of the cliff. The top has about the same ele-
vation as Mt. Willard. The course to the north edge of the Conway
granite on Willard is N. 57° W. Supposing these rocks to conform to
their course on the railroad, we should suppose the south part of the
schists corresponds to the Breccia adjoining the Conway granite.

Passing up the ragged edge seen in the heliotype, we find the Conway
granite again, directly over this cliff, as far to the upper precipice as
indicated upon p. 123. At the middle one the rock is very characteris-
tic, with prominent joints running N. 6^^° E., vertical. A small flume
ten feet wide has been excavated out of them, carrying a thin, light-
colored trap dyke. Other joints dip 50° N. 38° E., agreeing with the
position of Montalban schists half a mile to the north. The edges of
the schists are traversed at their lower edges (the upper cliff) by very
large granite veins, — some of them corresponding in lithological features
with the coarser varieties traversing the Notch cuts, and twenty or thirty
feet wide. Others possess a very fine grain, and are somewhat like the
finer Breccia cement, lacking the porphyritic aspect. All the rocks are
terribly decayed through weathering. The schists are much like those

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1/5

at the Notch at the junction. Half a mile to the north they hold essen-
tially the same position, all of them dipping 50° N. 38° E., but are very
evenly bedded with the mica in layers, and are not permeated with the
intense hardness that prevails below.

The character of the rocks upon the top and west side of Mt. Webster
may be seen to good advantage from the summit of Mt. Willey, across
the valley, because they are of different colors. The upper part is a
reddish-brown color, corresponding to the ferruginous Montalban schists.
These extend plainly from above the large cliff just described to a point
opposite the Willey house, where the gray color, indicating the occur-
rence of the Conway granite, takes its place. The upper rock is trav-
ersed by thirteen large granite veins, broadest at the lower edge of the
reddish rock, and ramifying into numerous branches above. Some of
them are tortuous, with an average direction parallel to the junction be-
tween the red and gray ledges. I have not been able to traverse exten-
sively the granitic slope beneath, but have thus far seen there only the
coarser Conway granite, occupying fully seven eighths of the surface.
In several places patches of the reddish color flow down into the gray,
sometimes irregularly. This is the result of aqueous action, and there is
no reason to believe the rocks have been much dislocated by faulting.
There are fourteen slides on the west side of Mt. Webster. From Willey
one sees also the pyramidal shape of Mt. Webster, as expressed on our
contour map. Visitors travelling along the valley beneath are led to
believe that the top is nearly horizontal. The highest point is at its
northern extremity.

We conclude that the line of union between the Montalban schists and
Conway granite is in general straight, but when minutely investigated,
jagged like a comb wanting occasional teeth. From this frayed edge
innumerable large segregated granite veins spread off into the schists
like a long row of immense branches of trees, mostly in their natural
vertical position.

Mt. Willey range of Slate. Our researches lead us to believe that this
rock has its southern termination near the summit of Mt. Willey, being
as wide as the peak at the depth of a thousand feet, say a mile and a half.
The dip on the summit is 80° W., and perhaps on the south side, near
their base, the slates may dip easterly at a somewhat smaller angle. On

176 STRATIGRAPIIICAL GEOLOGY.

the ridge the slate runs back on to the south slope of Mt. Field. There
is a gradual slope north-easterly from the base of the formation at the
south of Mt. Willey to a point on the railroad 2000 feet south of Willey
brook. From Mt. Webster this dividing line between the granite and
slates is very conspicuous, the former rock being bare and white, and the
latter black and obscured by bushes. The general course of this forma-
tion from the Willey summit to its extreme northern development, a little
north of Willey brook, is about N. 10° E.

The sudden falling off of the mountain south of Willey has been no-
ticed. It is due apparently to the disappearance of the slate, the broad
terrace-like hills beyond being composed of the underlying granite.
The slates stop suddenly, cut off as abruptly as the end of a plank.
They do not seem to have been altered into anything else, but have been
removed bodily. In character they are identical with the rock at Willey
brook, and in the valley running north-westerly from that point. I ob-
served no andalusite in it, but cannot doubt it exists as abundantly on
Mt. Willey as farther north.

A very interesting feature is displayed at the lower limit of this
formation, on the head waters of Kedron. The Conway granite there
approaches it, but between them is a harder variety of granite, accom-
panied with fragments of slate imbedded in it. The Conway rock is
surely the cementing material of the harder bunches with the slates.
This agrees with what has been described on the stream above Beecher's
cascades : in that, pieces of this newer slate have been cemented into a
brecciated mass by the Conway granite.

On the Portland & Ogdensburg Railroad these slates are exposed for a
width of 2700 feet, 700 north of Willey brook. Their usual inclina-
tion both south and north of the brook is 6"]° N. 82° E., with a reversed
dip a few rods north along the railroad. On top of Mt. Willard the dip
is north-westerly ; and on the way down the mountain I have noticed
the presence of an anticlinal of small extent near the line of junction.
The deep cut just south of the iron bridge over Willey brook has a
smooth westerly wall. As the same seam is perceptible down to the bed
of the brook, it is likely that a fault is indicated by it, though not one
of sufficiently great importance to complicate the structure. The ledges
here are beautifully filled with long crystals of andalusite.

irea. or N. 77" W. The p-

in, whose prineipal mass is composed o£ Montaiban schists,

raiiroao

^^

1/8 STRATJGRAPHICAL GEOLOGY.

way down a high chff presents a smoothed aspect, as if there had been a
shding of one rock over the other at their Hne of union. Near this place,
also, the breccia is better developed, attaining a thickness of twenty feet.
The lower two hundred feet above the railroad are obscured by a large
pile of debris.

On reaching the lower part of the small saddle back of the Mt. Field
spur the slates dip 50° S. 8° W. On the very ridge they seem to stand
about 85° N. 82° W. All about this tract of several acres extent the
strata are much contorted in small corrugations, and I also observed
masses of the breccia. South-westerly, in climbing up through the more
recent growth of trees, there is a light-colored quartzite. Farther north
I found no slates, but came to loose pieces of Conway granite, which may
possibly have come from neighboring ledges. I suspect the white, moist
rocks, of precipitous character, seen north of Willey brook at about the
same elevation with Mt. Willard, may be of this character. Higher up,
a bare ledge proves to be of the spotted or Albany variety, with nu-
merous joints a few inches apart, dipping 75° S. 8° W. On top of the
north shoulder of Mt. Field are ledges of greenish porphyry, not very
extensive. The small cone constituting the very highest point of Mt.
Field is composed of this same spotted rock, with joints dipping about
four degrees easterly, besides others nearly vertical. Combining these
observations with those mentioned on page 144, it appears plain that this
Albany granite is continuous from the south side of Mt. Field along the
ridge nearly to the top of Mt. Tom ; and it probably occurs beneath the
slates on the west side of Mt. Tom continuously to the smaller mountains
north.

A word as to the top of the north-east spur of Mt. Field. In the ascent
direct from the uppermost Beecher cascade, no rocks appear save the
spotted variety. The summit is double, and very prominent joints dip
75° westerly, nearly parallel with the slate on its west side, which we
have traced to this saddle from Mt, Willard. It is also clear that the
slates pass from this saddle down to Cascade brook above Beecher's
cascades, and thence northerly to Mt, Andalusite, where they cease as
abruptly as they started on Mt. Willey. I have previously noted the
character and position of these slates on the Mt. Tom region.

The conclusion to be derived from these statements is obvious. This

GEOLOGY 01' THE WHITE MOUNTAIN DISTRICT. 1 79

andalusite slate starts from Mt. Willey, pursues a course N. io° E. to the
railroad, thence climbs Mt. Willard about N. 75° W., and back of the Field
spur changes to N. 10° E. again, crosses Cascade brook, and after reach-
ing a very great altitude suddenly terminates. It is flanked on both sides
for a considerable part of its course by the Albany granite. If this was
a stratified rock, we should say that the structure of the slates was that of
an inverted synclinal, underlaid regularly by this constant inferior mem-
ber. In the present state of our knowledge of altered and eruptive rocks,
it cannot be said that these underlying granites are certainly not sedi-
ments, so thoroughly metamorphosed as to have lost their lines of orig-
inal bedding. The evidence in favor of their eruption, since the deposi-
tion of the andalusite slate, is increasing.

In the preceding description of the slates, I may have stated too
strongly their apparent distinctiveness as a formation from the neigh-
boring rocks. This is the impression one gets from their examination in
the field, uninfluenced by theoretical considerations. If we carry the
theory of metamorphism to an extreme, it might be said that the slates
could be altered into a granite by hydrothermal influences. If both rocks
contain essentially the same elements, it is conceivable that the fusion of
the dark slate might produce the spotted or the Conway granite. The
slate is penetrated largely by andalusite, a mineral devoid of alkali. If
either of the granites has resulted from the fusion of the slate, it is
plain the latter must contain considerable potash, else feldspar could
not be readily formed in the great abundance which is everywhere ap-
parent. Some analyses will be made of the slates in order to ascertain
whether an alteration of this andalusite slate into granite be possible.*

Two considerations may be stated which incline to the belief that the
slates constitute an independent formation, and have not undergone met-
amorphosis. First, in comparing together the courses of the strata back
of Mt. Willard, and the spur of Mt. Field, it would seem as if the slates
had been violently bent into their present trend by the subsequent erup-
tion of the spotted granite crowding into their eastern flank. The slates
are twisted and broken in many places, the fragments being cemented

* The results of one analysis show a deficiency of silica in the slate instead of alkali. This agrees with
the results of numerous recent analyses of the Cornwall killas by J. Arthur Phillips — Quar. jfoiir. Geol. Soc,
Aug., 1S75. He also insists that the granites are not derived from the metamorphosis of the slates.

I So STRATIGRAPHICAL GEOLOGY.

together by a granitic paste ; and oftentimes in the midst of the north-
westerly trend there are ledges and smaller masses retaining the northerly
course. It is easy to say that some portions of the original strike were
retained, even after the exertion of the disturbing agency, altering the
position of the principal portion of the areas in order to explain these
phenomena. Second, cases have been cited showing that fragments of
the slates occur imbedded in the underlying granites. This is most
easily explained by saying that pieces of the slates were broken off during
the disturbances connected with the eruption of the granite, and caught
in the fluid mass. If so, of necessity the granite came into being later
than the slate.

In a part of my labor in the Notch I had the pleasure of the company
of Professor Dana, who made many valuable suggestions and queries.
After communicating to him some facts observed after his departure, he
writes : " There can now be no reasonable doubt, I think, with regard to
that Notch valley being the course of an anticlinal, the veins and the
broken line of rock being so extensive. [See p. 167.] The stopping
short of the andalusite slate [on Mts. Willey and Tom] is strange. The
point of special importance in connection with it is, what rock appears to
be its continuation } Is it the porphyritic [spotted] granite that lies to
the west of it ? Is it a stop-off through a fault, or through a change in
the material of the stratum, leading to the development of a different
crystalline rock by metamorphism.?"

The distribution of the slates will be alluded to again further on, after
describing the other areas of this formation among the mountains.

T/ie NotcJi valley bctivcen Willey brook and Bcniis. Our observations
in the valley between the andalusite slates on Willey brook and the reap-
pearance of the Montalban gneisses at Bemis, are fewer than their imiaor-
tance demands. The first ledge of the Conway granite, 2000 feet below
the Willey brook, is mentioned on page 175. It is finer grained than
usual, and useful for building purposes. None of the spotted variety of
granite shows itself adjacent to the slates on their south side, as in the
case farther north. This Conway granite seems to conform to the posi-
tion of the slates underlying them. Opposite the Willey house this rock
is coarser, and closely agrees with its most common type of mineral
structure. Passing up Willey mountain it is displayed in many high

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. l8l

precipices, well situated for quarrying. In Kcclron there is an interest-
ing narrow dyke, from six to ten inches wide, of a light-colored soft
material, readily fashioned with a knife. Along the railroad one sees
other very pretty dykes of trap crossing the valley, and probably connect-
ing with similar exposures upon Mt. Webster. The Conway granite may
be traced to Cow brook, along the railway. It is followed by the Albany
variety, containing several trap dykes of great interest. In the numerous
cuttings below it is interesting to observe the change of color from
greenish or grayish to red, in proximity to each trap dyke, occasioned by
the oxidation of the iron present.

Frankenstein cliff is the name of the north-eastern extremity of the
Mts. Lowell-Andcrson-Nancy range, where it is cut by the railroad. It
is known further by the very high iron trestle-work adjacent on the south.
This cliff is chiefly sienite for about half a mile along the railroad, north
of the iron trestle. It resembles the rock of Mt. Whiteface, north part of
Passaconnaway, and much of what is called the "Chocorua granite." At
the north end of the ledge the hornblende is replaced by mica for a few
rods. Small cavities, lined with quartz crystals and containing a little
chlorite, are common in this ledge.

This sienite seems to occupy the position of the Chocorua rock, as
indicated heretofore, for in coming south from the Willey house we found
the usual succession of granites, — the Conway first, then the Albany, and
lastly the sienite. Near their several junctions there is an intermingling
of the adjacent varieties. Likewise in going south we find the reverse
order of succession beyond the iron trestle, though there are other varie-
ties which make the order of distribution somewhat perplexing. The
overlying place of the sienite is very clear. Where a reddish hard rock
appears, south of the trestle, one can see the sienite ledge above descend-
ing to the cliff from the south-west ; and immense blocks of the upper
rock have been detached by frost and fallen down to the level of the
railroad. The appearance of the sienite belt rising to the south reminds
us of the similar position of the Breccia granite on the south-east face of
Mt. Willard (page i68). At the lowest accessible point in the valley, at
the crossing of the Saco river by the carriage-road, not very far below
Frankenstein, there is an unmistakable extensive development of red
Conway granite. The upper and lower members of our granite series

1 82 STRATIGRAPHICAL GEOLOGY.

therefore occupy their proper places. Furthermore, we have as 3'et found
no indication of the uppermost rock in the southern development of Mt.
Webster across to Mt. Washington river. There are large boulders of
Chocorua granite in the last named valley whose source is unknown.
The granite cropping out at the angle between the Saco and Mt. Wash-
ington rivers is classed by us in our note-book with the Conway variety.
Up Sleeper's brook there is a ledge of schist, indicated in our collection, a
quarter of a mile above the Saco, but granite higher up ; and Giant's
Stairs is composed apparently of a fine grained variety of the Conway
rock. At the base of the stairs the rock is very fine grained and white.
Specimens from Mt. Resolution, and on the Davis bridle-path at two and
three fourths and three and a half miles north of the mouth of Mt. Wash-
ington river, are doubtfully referred to the Albany. Other specimens of
the same are put down between Mt. Crawford and Mt. Hope, and opposite
Nancy brook. The granite from the top of Mt. Crawford is like that
from Frankenstein cliff, but its western base belongs clearly to the lower
group. It here contains veins carrying fluorite, as on Mt. Webster.

There are several varieties of rock in passing up Bemis brook. From
near the railroad I obtained a very interesting boulder of schist for the
museum, showing curves in the strata, and small dislocations. Its source
has not yet been ascertained, but the rock is like the andalusite slate.
The accompanying plate will make a description of the curves and faults
quite plain. The stone is forty-five inches long and thirty-six wide. The
view on the left represents the top, and that on the right the side of the
specimen. On the top we recognize four small anticlinal axes, and a
wedge-shaped segment driven into the stone a distance of five inches ;
but the longer fault shows a displacement of only about two inches. The
shorter fault has cut transversely through the first anticlinal, and the
longer one passes across the next anticlinal. The third and fourth are
unaffected by shoving. Turning to the side of the stone, these four axes
are observable, and one of the faults, which develops a new ridge. On
the left is a smaller fault, not connected with those on top. Of the anti-
clinals, the first is the farthest to the left; the second disappears; the
third is almost lost, broadening very much ; while the fourth is much
more prominent, appearing on the extreme right. The amount of shov-
ing along the fault is two inches. The width of this side of the fragment
is two feet.

.^ i.li.c track iur a considciv:bio ci
<.pparently one of the varieties of the
ifications this rock occurs all the way up to T.i
dred feet above the road. It is usually muc^
the " Stair falls," pome of these jo'nts dip
'-vvelve to

■ Ki-

!vi:crmr.

.n

Ji.

A specif;^'

liiis journey was
rook to a peak o;
another mountain, thence south-west to Nancy mountain, and reports
the ledges as composed of granite. The specimens from Nancy pond i\
a fme- grained variety of the Conway series, containing much quar
This variety prevails in the neighborhood (see p. 146). At a mile r-;
of Nancy pond 'he granite is reddish and coarse grained. It is cc-
tinuous with that which is typical of the series at Bemis pond, and so <

lacent to

>i a milt

"rcz, ii>

-b tint vereip:

1 84 STRATIGRAPHICAL GEOLOGY.

History of Opinions Respecting the Age and Elevation of the
White Mountains.

These mountains have afforded scientific writers abundant opportunity
for the display of theories respecting the geological equivalency and ele-
vation of the strata. A citation of the most important among them will
illustrate the progress of scientific thought, and give credit to divers
original suggestions. The older writers generally believed in an igneous
ejection of granite, bursting through horizontal strata, pouring over them,
and throwing great masses upward with steep inclinations. These views
came not from original application to these mountains, but were a trans-
ference of the ideas of European authors to our ranges.

A very early publication was that by President Dwight, in his Travels
in Neiv Engla7id, volume 2, 1821. He writes thus concerning the Notch
(p. 147):

The Notch of the White Mountains is a phrase, appropriated to a very narrow defile,
extending two miles in length between two huge cliffs, apparently rent asunder by
some vast convulsion of nature. This convulsion was, in my own view, unquestiona-
bly that of the deluge. There are here and throughout New England, no eminent
proofs of volcanic violence ; nor any strong exhibitions of the power of earthquakes.
Nor has history recorded any earthquake, or volcano, in other countries, of sufficient
efficacy to produce the phenomena of this place. The objects rent asunder are too
great: the ruin is too vast, and too complete, to have been accomplished by these
agents. The change appears to have been effectuated, when the surface of the earth
extensively subsided ; when countries, and continents, assumed a new face ; and a
general commotion of the elements produced the disruption of some mountains, and
merged others beneath the common level of desolation. Nothing, less than this, will
account for the sundering of a long range of great rocks ; or rather, of vast mountains ;
or for the existing evidences of the immense force, by which the rupture was effected.

James Pierce presents a notice of a trip to Mt. Washington in 1823,
from Fryeburg, Me., to the Notch, and thence over the several peaks
to the summit, which hardly differs from what one would write at the
present day of the same route. He speaks of "Mt. Prospect" as the
name for the eminence now known as Pleasant.*

Prof. C. U. Shcpard, in 1830, speaks of the granite and other rocks
in the Notch. It "here offers the aspect of immense beds frequently

*■ Amcr. Jour. Sci., I, vol. 8, p. 175.

JPX^MK JC

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, l8$

divided by fissures in two opposite directions, one of whicli is vertical,
while the other is parallel to the plane of the horizon, the cuboidal or
prismatic masses being piled upon each other after the manner of rude
masonry." After speaking of the made noticed in the fragments below
what is now Mt. Willard, he says : f

The notices we had received concerning the geology of these mountains made the
appearance of any other rock than granite, quite unexpected ; and our surprise was not
a little heightened on being presented by Mr. Cook of Fryeburg, Me., with specimens
of a decidedly brecciated, or recomposed argillaceous slate, which he assured us, cov-
ered, to a considerable height, the flanks of the Kearsarge mountain. * * * I am
disposed to believe, that whenever these mountains shall be more closely studied than
they hitherto appear to have been, a much less degree of uniformity will be found to
exist in their composition than has generally been supposed ; though I am far from
supposing that granite is not the principal rock, and that it does not constitute the
summits of their most considerable elevations.

Viezus of Prof. O. P. Hubbard respecting the geology of the White
Moiuiiaijis, from American yournal of Science, I, vol. 34, 1838, p. 120:

The only particular to which I wish at jDresent to invite attention, is the nature of
the rock crowning the summit of Mount Washington. The peak he sees capped with
a rocky covering, destitute of vegetation, broken up into huge masses, which, as he
passes from rock to rock, seem as disjecta metnbra in the wildest confusion ; but when
he has once surmounted the peak, and recovered from the mingled emotions of sur-
prise, pleasure, and subUmity which fill his mind, and given his attention to nearer and
minuter objects, his satisfaction, if he be a geologist, will hardly be less than when
viewing the more distant and imposing scene.

The foundation or mass of the mountain, as it is seen in the deep gorges cut by
the slides in the western side, is granite; and the top has been stated, by those who
have and by others who have not ascended it, to be granite ; and Alpine travellers,
who have visited Mont Blanc, have thought they saw in the vast ruins surrounding the
summit, the remains of lofty aiguilles that towered above the present peak ; but let the
observer stand at the most elevated point, near the rude artificial monument, as in the
centre of a decapitated summit, and let him critically examine the rocks in the whole
circle about him, and he will soon discover the incorrectness of these opinions. He
will find the rocks stratified, layer upon layer, and symmetrically arranged around the
centre he occupies. The rock is mica slate, consisting of coarse mica and fine quartz,
occasionally with fine-grained veins of the two minerals, with a little feldspar, and
some considerable veins of white quartz. The uniformity of this surface, in level

'^ Amer. your. Set., \, vol. i8, p. 291.
VOL. II. 24

I 86 STRATIGRAPHICAL GEOLOGY.

and appearance, is such that a passage to the top is marked out by no ravines and emi-
nences, but the path leads directly over the ruins, and the guide himself is directed by
masses of white quartz, or collections of stones raised at proper distances. Near the
top are small black tourmalines, and above a small spring of water.

The case is clear. The mountain of granite was raised from the deep, bearing up
on its Atlantean shoulders this huge covering of mica slate that extends a quarter of a
mile below the summit, and by disruptive agencies has been fissured in every direction,
and reduced to ruins. The granite, instead of upturning the mica slate, and protrud-
ing at the centre of elevation, itself forming the peak, has broken it at some distance
from the centre, and we ought to find the long line of disruption of the mica slate, if
the rocks remain and are uncovered, very far down the mountain ; if not, in the low
grounds of the valleys.

Dr. Jackson s vicivs, p. 'j'j, Final Report Geology of New Hampshire.

Dr. Jackson ascended the mountain by the Crawford bridle-path, the
same now travelled direct from the Crawford house. I quote only the
geological statements :

On Mt. Franklin all traces of vegetation, excepting jjlants of an alpine character,
disappear. The rocks consist entirely of granite and gneiss, with occasional veins of
quartz. The geological features of Mt. Washington possess but little interest, the
rocks in place consisting of a coarse variety of mica slate, passing into gneiss, which
contains a few crystals of black tourmaline and quartz. The cone of the mountain and
its summit are covered with myriads of angular and flat blocks and slabs of mica slate,
piled in confusion, one upon the other. They are identical in nature with the rocks in
place, and bear no marks of transportation or abrasion by the action of water. On the
declivity of the cone occurs a vein of milky and rose-colored quartz, but it is not suffi-
ciently high colored to form elegant specimens. The geologist will be fully rewarded
for his toil in ascending this mountain, by the magnificent and comprehensive view
which may be obtained of the surrounding country. He will remark that the moun-
tains are not grouped at random, but form regular ranges, running in definite directions
coinciding with the axis of elevation. To the south-eastward three ranges of moun-
tains are seen, and appear to run N. N. E., while to the south-west the mountains run
in a nearly north and south direction. The valleys are observed to be regularly con-
tinuous between the mountains. The whole country, so far as the eye can reach, is
thickly clad with the primeval forest trees. [1840.]

After mentioning the observations of Messrs. Channing and Hale upon
Mt. Jefferson, noticed above (p. 115), Dr. Jackson remarks:

The results of this exploration were important ; since the observations made in the
bed of Israel's river prove the nucleus of the White Mountain range to be granite rock,

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 87

and the mica slate seen on the summit of the mountain, is but a superficial crust or
superimposed layer. [Page 160.]

In Volume I, page lo, I have reproduced Dr. Jackson's ideal view of
the stratigraphical structure of the White and Green Mountains, in their
relations to the formations of the adjacent states, with his figure. A few
critical remarks will be found there, expressive of what is correct and
what is erroneous in these views, according to the latest interpretation.

E. Hitchcock's victvs. In 1841 my father ascended Mt. Washington
from the old Notch house, and, in a paper upon Glacio-aqiicoiis action in
North America, makes the following statements respecting the rocks:*

The principal part of the White Mountains, I will not say all, appears to me to
consist of steep parallel ridges of granite and mica slate, running about north-north-
east and south-southwest, with occasional spurs. The Notch is a passage through the
highest of these ridges. * * * This ridge [Clinton to Washington] is composed
essentially of a peculiar kind of mica slate, occasionally containing feldspar, and some-
times traversed by veins of granite. It also abounds, as does the same rock at Monad-
nock, with a mineral which has been called fibrolite, but which demands further
examination. It often constitutes a large proportion of the rock. All the peaks, except
Clinton, which I ascended, (Jefferson and Adams I did not ascend,) 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 Washington, and downward
about one thousand feet. But in all the valleys between these peaks, more or less of
the rock in place appears.

Views of H. D. and W. B. Rogers. Of all the papers published upon
the geology of the White Mountains previous to 1869, that by the Pro-
fessors Rogers in 1846! is the most valuable, and therefore it is copied
here entirely, save a few paragraphs relating to some supposed fossils,
which they themselves subsequently discovered to be simply singular
mineral aggregations. %

The White Mountains, the most elevated of the mountain masses of the Atlantic
side of North America, have been hitherto regarded as consisting exclusively of the
granitic and gneissoid rocks under their several modifications, and as having originated
in the so-called primary periods of geological time. This common notion of their

* Trans. Assoc. Ainer. Geologists and Naturalists, pp. 183, 184.
t Amer. Jour. Sci., II, Vol. I, p. 411.
t /d.,U, Vol Y, p. ii5.

I 88 STRATIGRAPHICAL GEOLOGY.

great antiquity is to be ascribed to the highly crystalline texture of many of their more
conspicuous rocky masses, which, until closely scrutinized, do certainly bear a near
resemblance to the typical forms of the most ancient gneiss, mica slate and granite.
But it involves we conceive two errors, first, that of assigning to all the strata of the
gneissoid class, merely in virtue of their crystalline aspect, a date remoter than that of
the protozoic or earliest fossiliferous deposits ; and secondly, the error of supposing
that the strata of these mountains contain no organic remains. So long as their fossil-
iferous character was undiscovered, the metamorphic condition of these rocks might
naturally enough deceive the observer, and lead him to false inferences in relation to
their age.

Having in the month of July last, enjoyed the opportunity of studying with some care
the structure and composition of that part of the chain which is exposed to view in the
picturesque and deep defile of the Saco, we had the good fortune to detect in the vicin-
ity of the Notch, the fossiliferous character of a portion of the strata, and to see through
the metamorphic disguises in which intense igneous action has obscured these origi-
nally sedimentary palaeozoic masses. We succeeded in determining some of the organic
remains sufficiently to identify thereby some of the formations, much altered as they
are from the purely sedimentary aspect, and from these data we have attempted to
deduce some inferences respecting the //;//// of aittiqnity of these mountains, and the
date of their elevation. By detecting in many of the pseudo-granitic rocks a genuine
sedimentary stratification, we were able to follow in sundry places the true direction
of the almost obliterated bedding, and to discover the course of the anticlinal axes.
These once clearly recognized, led us finally to conclusions which have much interested
us in regard to the structure of the whole chain and the nature of the forces of eleva-
tion. In the present short paper we j^ropose to submit a concise abstract of these
observations, and the results to which they have brought us.

By inspecting the accompanying little map, the reader will notice that the general
direction of the Gorge of the Saco, neglecting the local windings in its course, is
nearly from north to south. In one place, about half-way between Crawford's and the
Willey house, the contracted valley as we trace it south bends abruptly to the west-
ward, and in the distance of perhaps a furlong sweeps back again into its former south-
erly direction, making a double or sigmoid curve. This feature is especially favorable
to the exhibition of the range and dip of the rocks, which are here exposed endwise
in the transverse section. In the mountain on the north and west of the Gorge, the
end of which is full in front of the traveller as he ascends the valley from the Willey
house, the stratified structure of the rocks throughout this gigantic ridge, is plainly to
be seen in the differently colored perpendicular belts which outcrop edgewise along its
naked and nearly mural face.

At the Notch (represented in the sketch at a) the rocks on both sides of the narrow
chasm are traversed by two sets of nearly vertical planes or joints, the one running
nearly N. E. and S. W., the other nearly N. W. and S. E. Though in this place the
stratification is but obscurely indicated, we succeeded in making out the planes of

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 89

bedding; and in some cases with sucli satisfactory clearness as to prove the true strike
of the beds to be N. E. and S. W., and the dip to be for the most part vertical, but
with some local arching. Observations made both at this locality and elsewhere, in-
duced us to regard the rocks of the Gorge generally as a group of highly metamorphic
sandstones and slates, traversed by enormous beds and veins of syenitic granite, by
the heating agency of which they had for the most part been rendered semi-crystalline,
and in some cases had even been transformed into apparent gneiss and granite. At
certain points in these altered strata, the original sedimentary structure is still dis-
tinctly retained ; and at one locality we were so successful as to discover well charac-
terized impressions and fragments of fossils, from which we have been able, safely as
we think, to approximate to the geological age of the strata, as well as to the epoch of
the earliest movement of elevation.

At the curve in the valley, where the anticlinal axis xy crosses the Gorge obliquely,
entering the end of the ridge already alluded to, and from that point down to the Wil-
ley house, the rocky fragments dislodged from the naked and steep sloj^es on either
side, consist chiefly of a finely laminated hard sandy slate of a bluish color, and a
coarse very compact rock of similar composition ; and mingled with these are occa-
sionally found masses of the same composition, but wearing a more altered aspect,
some of them containing crystalline spots and white amygdaloidal kernels, the obvious
indications of an advanced stage of igneous metamorphosis. These fragments are
extremely instructive ; for they exhibit nearly all the later stages of alteration, from
the ordinary sedimentary texture to the diffusedly crystalline one. In some cases we
see the planes or lines of sedimentary deposition coexisting with a general but not
fully perfected crystallization, in which however may be distinctly discovered genuine
feldspar, augite and 7nica. Such specimens are to be viewed as an incipient horn-
blendic gneiss, in which through the sedimentary granular structure, typical of the
secondary strata, may be seen everywhere and intimately dispersed, the crystallized
definite mineral aggregates equally typical of the so-called primary rocks. Many of
these specimens seen facewise, would pass for genuine ancient gneiss ; but looked at
edgewise, they betray equally unequivocal marks of their sandstone nature and origin.
Among the more argillaceous altered rocks, are some which have evidently once been
sandy shales, but which now consist of a purplish gray semi-crystalline base, imbed-
ding several obscurely developed minerals. These rocks likewise contain serpentine,
talc, and other silico-magnesian species, as well as some clearly insulated grains of
crystalline quartz.

About one third of a mile below the northern entrance of the Notch, on the west
side of the Gorge and therefore not far from the extremely wild and picturesque cas-
cade called the Flume, there occurs especially in the craggy summit of the mountain,
a thick-bedded white semi-crystalline altered sandstone, which is intersected by injec-
tions of feldspathic granite, and is itself in many parts concreted into a near approxi-
mation to a binary granite composed of distinctly developed cjuartz and white feldspar,
with a few sparsely scattered specks of mica. In its weathered surfaces this rock

IQO STRATIGRAPHICAL GEOLOGY.

wears a close resemblance to some fine grained quartzo-feldspathic granites, but upon
inspecting a fresh fracture with a magnifier, we instantly perceive many rounded grains
of quartzose sand : we perceive moreover much of the feldspar to be only imperfectly
formed, as if congealed when in transitit, though the mica has more nearly reached
the standard condition which it has in granite. In some of the coarser varieties of this
white rock, small distinctly rounded pebbles of quartz are to be seen, giving unequivo-
cal evidence, even to the naked eye, of its being an altered sandstone. Upon inspect-
ing many varieties of this rock, we felt no hesitation in deciding it to have been a
coarse silico-argillaceous white sandstone, now almost granitized by extensive meta-
morphic action. The slope of the steep mountain side is in many places strewed even
to its base, with long trains of the angular blocks of this seeming granite fallen from
the high crowning cliffs above. Seen in places near the summit of the mountain, the
rock presents two or more systems of extensive and very regular joints or planes of
cleavage, by which the whole mass is cut into cubical and trapezoidal blocks. This
jointed condition, itself so significant of an extensive internal structural change, is a
principal cause of the magnitude of the piles of fragments which clothe the slopes of
the mountain. It is beheld even more conspicuously in the shattered crests which
bound the valley above and below the Willey house, where an almost continuous thick
sheet of angular debris conceals the stratification except in the craggy precipices near
the summits. Those sublimely terrific and desolating slides which have occurred here
at different times, are therefore primarily attributable to this jointed structure. This
has permitted the elements to dislodge the fragments and heap an unusually abundant
and heavy talus high upon the slopes of the steep hills, where its unstable equilibrium,
weakened by saturation from copious rains, has caused great bodies of the rubbish to
give way and rush down with destructive impetuosity into and across the bed of the
narrow valley beneath.

Generalizing the position and dip of these clearly mechanical but altered strata, on
both sides of the Gorge of the Saco, we think that there are ample data for inferring
the existence of a great anticlinal fold or axis, crossing the valley in a direction nearly
N. W. and S. E., as represented by the line x y. This axis is plainly indicated on
each side of the Gorge by a deep depression in the summit line of the mountain, espe-
cially in the crest which overlooks the valley on the western side. At this latter place
the situation and bend of the axis line is easily discernible, even from the valley below,
in consecjuence of the contrast of certain dark-colored argillaceous strata, in color and
bedding, to the other rocks.

In the flank of the mountain, capped by the highly altered white granitized sand-
stones already mentioned, we discover on the west side of the Gorge, about one third
of a mile below the Notch and within one hundred feet of the road, a thick bed of a
light brownish altered shale, imbedded with a nearly vertical dip between strata of the
metamorphic sandstone before referred to, as so nearly granitic in its aspect. This
shale is replete with fossils of recognizable genera and species, but in the state of
casts and mere impressions. ******

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, I9I

This stratum, so remarkably fossiliferous, is only a few yards in width where it is
exposed at the locality we have designated, and it there lies with a nearly vertical dip,
between masses of highly altered sandstone, possessing, until carefully inspected, a
close resemblance to granite. The white feldspathic or granitized sandstone, already
described as crowning the top of the hill, belongs probably to one of these including
masses ; but from the perpendicularity of the dip it is obviously impossible to infer
which was originally the superior formation. Near the summit of the ridge, however,
the sandstone seems to overlie the shale ; but an inversion of the dip here might very
naturally exist, and it is necessary therefore to appeal to some other evidence than
that of position merely to determine the stratigraphical order of these rocks. As the
altered white sandstone in the portions examined, is apparently destitute of organic
remains, we have no feature to guide us but its composition and aspect. These are
well marked and strongly indicate its identity with the Levant white sandstone, (or
Shawangunk grit.) To no other formation in the whole Appalachian series, except
perhaps the primal sandstotie, (Potsdam sandstone,) does it bear any near resemblance,
and its affinity even to the primal sandstone is rather remote. The shales belonging
to the primal rocks contain moreover scarcely any fossils and certainly none of the
species here enumerated, and since there is no visible hiatus in the strata indicated by
an unconforming dip, this argument may be held to be conclusive. We are therefore
disposed to regard the two formations, the white sandstone and the fossiliferous shale,
as the equivalents respectively of the Levant white sandstone and one of the higher
Levant shales near the horizon of the fossiliferous iron ore. Upon this view some of
the intermediate shales are absent, and when we advert to the distance between the
White Mountains and the nearest outcrop of the Levant series in New York, this ought
not to surprise us. Upon the less probable conjecture that the fossiliferous bed is a
portion of the Matinal shales, no assumption of a deficiency in the series is required,
for the Levant white sandstone comes naturally next in the ascending order. The
general conclusions to which we are brought by this unexpected discovery of a fossil-
iferous formation, related evidently to one of the earlier Appalachian periods, are not
however in the slightest degree affected by this trivial amount of uncertainty respecting
the age of either bed. We proceed therefore to state the inferences deducible from
the foregoing facts.

One of the most interesting conclusions to be drawn from the evidence afforded by
the above described fossiliferous strata, relates to the geological age of the chain of
the White Mountains. These strata present convincing proofs that the region, now
occupied by this mountain chain, was overspread by the waters of the ancient Appala-
chian ocean at an era as late in the Palaeozoic ages, as the Matinal, or more probably
the Levant periods. Placed as the district is, immediately between the nearly contem-
poraneous formations of the states of Maine and New Brunswick on the one hand, and
Vermont and New York on the other, it fills up an interval in the area of the Appala-
chian rocks, which hitherto seemed vacant, and suggests strongly that the waters of
the Matinal or Levant eras, extended continuously across at least all northern New

192 STRATIGRAPHICAL GEOLOGY.

England. As it is known that the Appalachian strata abound as far to the N. E. as
Nova Scotia, and perhaps Newfoundland, and spread to a great distance north and
north-westward in the continent, the prodigious magnitude of the Appalachian sea, at
least in its earlier periods, is made apparent. But while these fossiliferous beds of
the White Mountains make it probable that the continuity of this sea was unbroken by
any land in the position of New Hampshire before the Levant period, they indicate as
plainly that some land did emerge after this period had commenced. How long sub-
sequent to the deposition of the earlier Levant strata that portion of the bed of the
ocean was uplifted into land, it is not practicable very positively to ascertain, until we
are certain of the latest age in which any of the fossiliferous rocks of the White Moun-
tains were produced. That the elevation was before the Carbottiferous period, which
witnessed the final draining of the Appalachian sea, seems manifest enough from two
considerations.

It is almost certain, in the first place, that none of the Appalachian strata of the mid-
dle or latter ages were deposited within this region ; for no traces of the coal rocks
nor of the fossiliferous J'ostmedial s/iales, (Marcellus shales, &c.,) nor any of the red
shales referable either to the later Levant or the Ponent (Catskill group) periods have
yet been met with : and since these newer palaeozoic formations abound both to the
S. W and N. E. we must infer that their absence in this locality is due to a lifting out
from the bed of the sea previous to their deposition. Had they been dejDOsited within
this area, some remnants of these strata would almost certainly have been preserved
from denudation in the close folds or synclinal bends of this contorted district. In the
second place, there is abundant evidence in the region of the Hudson valley, where
the Levant rocks rest almost horizontally on the upturned edges of the Matinal, that
the bed of the Appalachian waters underwent a local disturbance at the close of the
Matinal period, and it is equally obvious that the direction of this disturbance, as seen
in the course of the axes of elevation and depression, was different from that of the
subsequent movement by which all the deposits at the end of the Appalachian ages were
contorted and upraised. So in like manner we may perceive, in the structure of the
White Mountains, the proofs of two distinct intersecting systems of dip, the compo-
nents of two separate sets of axes or contortions of the crust, indicating two different
epochs of elevation. One of these, and apparently the latest, is a N. N. E. and S. S.
W. set of anticlinal and synclinal folds ; and is therefore probably a part of the gen-
eral movement which lifted the whole Appalachian or Alleghany chain, and drained
away the palaeozoic waters ; but whether the other accords as nearly in direction and
date with the earlier system of the Hudson valley, the epoch of which was either at the
close of the Matinal or early in the Levant times, is an important and interesting ques-
tion which only future research can answer. The most natural inference from all the
facts would seem to be, that in the somewhat disturbed period last referred to, when,
as geologists are already aware, all the more ancient Appalachian rocks, from the ear-
liest to perhaps the Levant sandstones, suffered a contortion and general outlift in the
region which is now the northern part of the Hudson valley, the same disturbance and

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I93

elevation of the earth's crust extended to the district which is now the White Moun-
tain chain. If we conceive indeed the whole of the wide tract of undulating and in
some places mountainous surface, from the upper Hudson and Lake Ontario, eastward
to Maine inclusive, and possibly a large territory north of the St. Lawrence, to have
emerged from the waters into permanent land, during the close of the Matinal period
and the first ages of the Levant, while the still wider spaces to the S. W. and N. E.
remained undisturbed, for the reception of later strata, we shall be able to interpret
many imijortant facts in the geological structure not only of this ancient district but in
that of the neighboring regions.

The hypothesis which supjioses that the bed of the Appalachian ocean was violently
and extensively agitated by a succession of earthquake movements, at the end of the
Matinal and early in the Levant periods, resulting in the conversion of all northern
New York and New England, and probably the whole south-eastern border of that sea
into permanent dry land, supplies us in the first place with an explanation of the un-
conformable superposition of the Levant ui)on the i\Latinal rocks, discovered by one of
us in 1837 near the city of Hudson, and visible at a number of other points E. and N.
E. of the Catskills. It furnishes moreover a cause for the extremely wide diffusion,
and the coarse conglomeritic composition of the early Levant sandstones, amid the
pebbles and sand-grains of which, are many fragments obviously derived from the
uplifted and broken Matinal and Primal strata. It provides furthermore a physical
reason for the marked transition observable in the species, when we ascend from the
organic remains of the Matinal to those of the Levant formations. An era of paroxys-
mal action would be naturally the period of a modification in the conditions and forms
of life, for extensive and permanent changes would arise in the bed of the sea, the
waters would grow shallow in many places, would deepen in others, their temperature
and their currents would alter, and even the proportions of the elements held in chem-
ical solution, which are the very pabulum of the aquatic races, would sustain some
change. But perhaps the most interesting application of the hypothesis here referred
to, is the explanation it affords of the excessively crystalline or metamorphic condition
of the Appalachian deposits in the district supposed to have undergone this ancient ele-
vation. Upon this supposition these districts, embracing nearly all New England and
the Atlantic slope of the Middle and Southern states, were the areas of chief move-
ment, while the other portions of the Appalachian sea were but slightly affected. Here
therefore the crust underwent the maximum degree of dislocation and of heating, and
the newly precipitated surface sediments were rent, brought into contact with the in-
tensely heated veins and dykes of internal molten matter, and baked and probably
partially crystallized, while those of the remoter and still submersed tracts were but
slightly acted on. As these districts, the south-eastern and north-eastern parts of the
Appalachian basin, were the first to be invaded by igneous action, so they continued,
as it would seem, to be the quarter where this action was oftenest repeated, and where
at each epoch of disturbance, especially that which witnessed the final drainage of
the Appalachian sea, it was greatly the most energetic. The whole structure of the
VOL. II. 25

194 STRATIGRAPHICAL GEOLOGY.

Appalachian chain supports this conchision ; the trutli of which is confirmed by the
excessively folded and dislocated condition of the strata along this whole belt of
country, and the gradation to features of less and less disturbance as we cross the
strata westward still further, by the progressive flattening of the anticlinal arches, by
the decreasing amount of crystallization in the rocks, and even the increasing cjuantity
of the volatile bitumen in the coal. When we advert to this repetition of igneous ac-
tion along this chief belt of volcanic force, upon the early elevated Primal and Matinal
deposits, we can no longer wonder at their highly metamorphic condition, nor hesitate
to impute to such cause any extent of lithological alteration exhibited by portions of
the strata, even to the aping of true granite and gneiss.

The suggestion we have here made, that the Primal and Matinal rocks of the White
Mountains emerged from the waters in the Levant period, and were elevated into anti-
clinal and synclinal flexures with a different strike from those of the more extensive
crust undulations of the late carboniferous date, offers a natural cause, v/e think, for
the superior elevation of their outcrops in this mountain chain, compared with their
height in the Green Mountains and other districts where only one system of axes, upon
a large scale, is discernible. As the level of the water is highest at the intersection of
two crossing billows, we can understand why in a region of two interfering sets of dips
or archings in the strata, such as we see indicated in the great defile of the Saco, there
should coexist a series of loftier peaks than are anywhere else presented in the general
mountain chain. The same intersection of axes of diff'erent geological dates has prob-
ably produced in like manner the very elevated and pyramidal group of mountains
between Lake Champlain and Lake Ontario, to which the general name of the Adiron-
dack range is given. The prodigious elevation and insulation of the peaks of the Alps
have likewise manifestly originated in the want of coincidence in the great folds or
axes, during the successive movements of elevation.

Vieivs of y. P. Lesley. The fullest statement of the views of Mr.
Lesley, which I have seen, is contained in the Proceedings of the Acad-
emy of Natural Sciences of PhiladelpJiia, for i860, page 363.

Mr. Lesley stated briefly the results of some observations he made in the White
Mountains of New Hampshire during the summer. His visits to this region in 1849,
and subsequent years, had laid the foundation for a growing conviction that the range
of the White Mountains would prove to be syticlinal instead of anticlinal, and there-
fore of probably Devonian age. A section which he made in 1857, along the Grand
Trunk R. R., showed him the synclinal structure, with comparatively low dips, and at
least two main anticlinal divisions. The profile in the Franconia notch is evidently a
cliff outcrop of a horizontal plate. The newly opened Greeley Mountain House in
Waterville, in a cul-de-sac valley at the head of Mad River, and six or eight miles in
an east line through the woods from the Flume House, is surrounded by bold outcrops
of nearly horizontal massive plates of granite. Ascending Mad River from Campton,

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 95

the traveller has the White-face range on his right, with apparent gentle dips to the
north-west. But on his left he has the Welch mountain range and Mount Osceola,
with an unmistakable and universal dip, never over 15°, and much of it under 10°, to
the south-east, which can be studied for at least seven miles, north-east and south-east.
Turning to the left and ascending Mount Osceola (which Mr. Lesley found by barome-
ter to be over 2600 [feet] above the Greeley House, and therefore not much lower than
Mount Lafayette), the bridle path mounts over successive outcrop edges of perfectly hor-
izontal plates of granite, as evidently and regularly bedded as any of the sandstone
masses of the Alleghanies, the bed planes not being at all disguised by the cleavage
planes. Between these plates of granite lie plates of unchanged dark blue sandstones ;
a rock which at the cascades (two miles from the house in another direction) has been
mistaken for greenstone trap. The successive terraces and cliffs of the mountain are
evidently the consequences of this horizontal and alternate structure. As in other
horizontal mountain plateaus the terraces here are projected between the ravines in the
form of noses, with straight crests, and terraced or stepped at their ends. In fact, to
a practiced topographical eye, the aspect of the whole White Mountain range is that of
synclinal erosion.

Other considerations reinforce this opinion. The continuation and broadening of
the range north-eastward through Maine and Lower Canada, where supersilurian rocks
abound, — the termination of the range south-eastward before reaching Massachusetts
and Vermont, as the Alleghany synclinal stops at Catskill before crossing the Hud-
son,— the presence of horizontal rocks at Worcester and more generally than would be
supposed through middle New England, — the fact that the Connecticut Valley runs
everywhere under the western escarpment of the White Mountains, separating it from
the Silurian range of the Green Mountains, — and the presence of Potsdam and other
low formations in eastern Massachusetts — all these facts would find their explanation
in a synclinal terminal eroded structure of the White Mountain mass.

The granite of Mount Osceola and the surrounding heights consists of large crystals
of feldspar, smaller crystals of quartz and smaller flakes of mica. Here and there
hornblende appears. The rock bears no resemblance to the subsilurian Highland and
Blue Ridge range, and Adirondacks. It is friable under the weather, shedding its
crystals upon the ground under every overhanging ledge. The boulders are rounded
by the weather action apparently more than by movement ; for they have only travelled
down the slopes beneath the cliffs from which they have fallen, and where those that
remain are sharp-angled. The peculiar gravel and sand of the Mad River Valley is a
local drift of similar origin. The metamorphism of these granites is considered by
Logan, Hunt, and others, as no longer disputable. They could easily originate in the
clayey sandstones of Formations VIII, IX, and X, of the Appalachians.

Considering the whole White Mountain mass a synclinal plateau, then the summit of
Mount Washington, which is such an acknowledged anomaly, becomes regularly the
single residual fragment of the highest formation which escaped erosion. Its rock is
so different in texture and structure from the rest of the mountains that no other expla-

196 STRATIGRAPHICAL GEOLOGY.

nation seems possible ; and if this Iiypotliesis be adopted, tliere is no longer any need
of that which supposes the submergence of New England up to the base of the head of
Mt. Washington and no higher, leaving the head in the air to escape the general round-
ing and polishing action. It becomes easy to consider the external difference due
rather to the difference of the rock formations above and below that horizon.

It is to be hoped that a systematic explanation will be made of this interesting region
and the structure made out and mapped, so that we may arrive at conclusions, instead
of venturing conjectures.

Viezvs of T. Stcrry Hunt. At the Cambridge, Mass., meeting of the
American Association for the Advancement of Science, 1849, ^r. Hunt
made an oral communication upon the results of the geological explora-
tions of Canada, and the conclusions to be derived therefrom respecting
the age of the New England rocks. The substance of these remarks was
printed in t'he official record of the meeting, also in American Journal
of Science, II, vol. ix, p. 12. Reference is made to the section from Lake
Memphremagog across to Canaan, Vt., by W. E. Logan, in the report on
the geology of Canada for 1847-48, which afforded the data from which
the conclusions were drawn. The fossiliferous rocks of the St. Francis
valley are referred to the Niagara grouj^, which are continuous with the
"calcareo-micaceous formation of Prof. Adams," in Vermont. Resting
upon this Niagara group in Gaspe is a body of arenaceous rocks, 7000
feet thick, corresponding to the Chemung and Portage groups in New
York. "To this," he says, "may perhaps be referred in part the rocks of
the White Mountains."

Similar views are met with in a paper on the Crystalline Limestones
of North America, in the American Journal of Science, II, vol. xviii, p.
199, 1854.

When we consider the geographical position of the Upper Silurian rocks in the
Connecticut Valley on the one hand, and the coal field of south-eastern Massachusetts
on the other, we can scarcely doubt that the intermediate gneissoid and hornblendic
rocks, with their accompanying limestones, are the Devonian strata in an altered
condition.

In 1870 Dr. Hunt wrote a letter to Prof. Dana upon the geology of
eastern New England, in which he proposed the name of Terranovan
series for the rocks to which the White Mountains were supposed to
belong; and conjectured that their age was "between the Laurentian

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 1 9/

and the Quebec group." To this publication I have already made abun-
dant references in Volume I, page 522.

In 1 87 1, in the presidential address before the American Association
for the Advancement of Science, Dr. Hunt thus defines the White Moun-
tain series:

This series is characterized by the predominance of well defined mica-schists inter-
stratified with micaceous gneisses. These latter are ordinarily light colored from the
presence of white feldspar, and, though generally fine in texture, are sometimes coarse-
grained and porphyritic. They are less strong and coherent than the gneisses of the
Laurentian, and pass, through the predominance of mica, into mica-schists, which are
themselves more or less tender and friable, and present every variety, from a coarse
gneiss-like aggregate down to a fine-grained schist, which passes into argillite. The
micaceous schists of this series are generally much richer in mica than those of the
preceding series, and often contain a large proportion of well defined crystalline tables
belonging to the species muscovite. The cleavage of these micaceous schists is gen-
erally, if not always, coincident with the bedding, but the plates of mica in the coarser-
grained varieties are often arranged at various angles to the cleavage and bedding-plane,
showing that they were developed after sedimentation, by crystallization in the mass ;
a circumstance which distinguishes them from rocks derived from the ruins of these,
which are met with in more recent series. The White Mountain rocks also include
beds of micaceous quartzite. The basic silicates in this series are represented chiefly
by dark colored gneisses and schists, in which hornblende takes the place of mica.
These pass occasionally into beds of dark hornblende-rock, sometimes holding garnets.
Beds of crystalline limestone occasionally occur in the schists of the White Mountain
series, and are sometimes accompanied by pyroxene, garnet, idocrase, sphene, and
graphite, as in the corresponding I'ocks of the Laurentian, which this series, in its
more gneissic portions, closely resembles, though apparently distinct geognostically.
The limestones are intimately associated with the highly micaceous schists containing
staurolite, andalusite, cyanite, and garnet. These schists are sometimes highly plum-
baginous, as seen in the graphitic mica-schist holding garnets in Nelson, New Hamp-
shire, and that associated with cyanite in Cornwall, Conn. To this third series of
crystalline schists belong the concretionary granitic veins abounding in beryl, tourma-
line and lepidolite, and occasionally containing tinstone and columbite. Granitic veins
in the Laurentian gneisses frequently contain tourmaline, but have not, so far as yet
known, yielded the other mineral species just mentioned.*

**********

Although I have in common with most other American geologists, maintained that
the crystalline rocks of the Green Mountain and White Mountain series are altered
paleozoic sediments, I find, on a careful examination of the evidence, no satisfactory

* Hunt, Notes on Granitic Rocks; Arner. your. Set., Ill, i, 182.

198 STRATIGRAPHICAL GEOLOGY.

proof of such an age and origin, but an array of facts which appear to me incompatible
with the hitherto received view, and lead me to conclude that the whole of our crystal-
line schists of eastern North America are not only pre-Silurian but pre-Cambrian
in age.

Views of G. L. Vosc. In a paper before the American Association
for the Advancement of Science, at BurHngton, Vt., 1867, Mr. Vose re-
marked as follows :

Regarding the arrangement of the great central mass of rocks forming the main
chain of the White Mountains, it was stated that this portion of the group appeared to
have neither the anticlinal build of the older geologists, nor yet the regular synclinal
build more recently suggested ; but that the top of Mt. Adams, of Mt. Jefferson, of
Mt. Clay, and the section from Tuckerman's Ravine through the Lakes of the Clouds,
all seemed to show a prevalent steep dip to the north and north-west ; and it was sug-
gested that the main chain of the White Mountains was formed by a fragment of the
western slope of an immense anticlinal wave, of which the crest would have been over
the Peabody valley, and of which perhaps a fragment of the eastern slope may be
found in the opposite and parallel range of the Carter Mountains ; in which case the
Peabody valley would be a valley of denudation.

In 1869 Mr. Vose prepared a report upon special details of the geology
of Jackson, Conway, Mt. Pequawket, the Ossipee mountains, etc., which
was printed in the annual report for 1871. As he indicated no generali-
zations concerning the structure of the mountains, it will be unnecessary
to reprint any portion of it here.

After the presentation of the few remaining facts relating to the dis-
tribution of the White Mountain formations, I will offer a few general
considerations concerning their structure and probable age.

Sketch of the Geology along the Grand Trunk Railway, from
Island Pond, Vt., to Gilead, Me.

BY ;. H. HUNTINGTON.

As the rocks are more accessible along the lines of our railways, we
give here a summary of the facts relating to the geology on the line of
the Grand Trunk Railway.

As a view of the crystalline rocks, the geology along this line is
intensely interesting; and so varied are the rocks that at every turn,
almost, the scenery changes.

The artist is not often satisfied to place upon his canvas a view as
seen from a single point. Here he traces the bold outline of a mountain ;

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. I99

near by, the foot-hills, and elsewhere the trees and the swelling hills
that form the foreground of his picture ; but here, as we ride along, the
changes are so rapid that we have these combinations in a single picture.

The swelling undulations of the gneiss ; the pyramidal hills of por-
phyrite, broken by dizzy precipices ; the rolling hills of the siliceous and
chloritic schists, the vertical strata of which have been worn and torn
and ground by the glaciers of the great ice age ; the mountains of gran-
ite, that have been crumbling by slow degrees through the ages ; and,
finally, the mica schist and gneiss of the White Mountains, that have the
strata crumpled and contorted by a thousand foldings, and here form
bold, projecting points and sudden recesses, that break the mass into
such picturesque wildness, — all form not so much a single picture, per-
haps, as a general panorama, each view of which has some point of
beauty which seems to excel all the others.

Bluff mountain, directly north of Island Pond, is mica schist. The
rocks, left bare by the fires that have swept the vegetation from its sum-
mit, show a reddish tinge, and point to the fact that they are ferruginous.
These rocks are cut by the railway north-west of the village, where they
have an easterly dip.

At the village near the station there are huge moraines, made up for
the most part of very coarse material derived chiefly from granitic rocks,
probably those in Morgan and Norton. East of the village we come to
an outcrop of a peculiar granite, probably intrusive. The quartz which
very largely predominates is gray and vitreous. The mica is a rusty
brown or black; the feldspar, when found, is dark and triclinic. This
rock extends ten miles east of Island Pond, Near its eastern limit, at
Nulhegan station, there is in this rock a bed of very fine-grained granite.
It is quarried to some extent, and is used along the line of the railway.

After crossing the Nulhegan river, going east, we find a kind of sand-
stone schist, often thick bedded, but elsewhere foliated and micaceous,
passing into mica schist. This rock is not cut by the railway, but is
found to the north along the carriage-road ; while to the south of the
railway we find the White Mountain gneisses. Along the Connecticut,
in the vicinity of North Stratford, we find mica schists with strata nearly
vertical, but with varying strike. In this rock, west of the river, there is
a variety of andalusite somewhat rare. It occurs in crystals of a reddish-

200 STRATIGRAPHICAL GEOLOGY.

brown color, not far from an eighth of an inch in diameter. The mica
schist is continuous south below Stratford Hollow, but varying consider-
ably in texture. Some of the last outcrops of this rock on the south,
where it approaches a hydro-mica schist, have the strike E. and W., but
the strata are nearly vertical. The inclination at J. Merriam's is 80°
southerly. The railway keeps on the drift and terraces of the valley, and
nowhere cuts this rock. We have described these rocks as Huronian,
except the schists at Island Pond, which probably belong to the Atlantic
series. Rocks similar to those near North Stratford, and containing the
same kind of andalusite, are found in Franklin county. Me., adjacent to
porphyritic gneiss.

As we enter Northumberland we come to an entirely different class of
rocks, that extend along the railway nearly to the tov/n of Stark. They
consist chiefly of chloritic feldspathic gneisses, and chloritic siliceous
schists ; but on the eastern border the rock is more an argillaceous sand-
stone schist. Southward, hornblende and epidote are frequent constitu-
ents of this rock. At Groveton there are many outcrops that show some
of its different phases, and here, included in them, there is an iron ore,
which, with the rock, forms a breccia. The strata in the vicinity of the
notch have a north and south strike, are nearly vertical, and are arranged
in a series of folds. At Groveton we see the pointed summits of the por-
phyrite mountains. The most marked of these is Mt. Lyon. Although
the railway nowhere cuts it, yet the high ridge immediately south of the
railway in Stark is composed of this rock. It has a dark, compact feld-
spathic base, with crystals of feldspar, probably triclinic. Northward the
Percy peaks are peculiar in their dome-shaped summit, not so flat as
ordinary granite, neither are they as sharp as the mountains of porphyrite.
The explanation is found in the constituents of the rocks. Crystalline
feldspar very largely predominates ; there is some black mica, and a very
small proportion of hornblende. The feldspar does not so readily decom-
pose as that of the coarse granite to the north, but resembles that of Mill
mountain. In the west part of Stark, on a hill between the railway and
the river, we have a granite unlike that found elsewhere. It resembles
the Conway granite and the coarse varieties found in Columbia, but it dif-
crs in being more compact, of finer texture, and having a feldspar more
decidedly flesh-colored. Its proximity to the railway, and the scarcity of

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 20I

building-Stone in this part of the state, make it worthy of attention for
local, if not for more extended use. This granite, at least along the rail-
way, is limited to this hill, for the next outcrop of rock is at Devil's Slide,
just west of Stark station. Here we have a variety of rocks. At the
west side the rock is a beautiful sienite, but unfortunately it is not easily
wrought. Going up the steep ascent, the quartz disappears, and in places,
also, the hornblende, so that we have only a crystalline aggregation of
feldspar. Half-way up the rock is colored by manganese and other sub-
stances, so that it is a dingy mass, mostly feldspar, with a very little
hornblende ; and we have included the whole under the general term of
porphyrite. The east end of the slide is a dark siliceous schist, that
stands vertically by the side of the intrusive porphyrite, but there are
places where it is penetrated by it ; and boulders forming a breccia can
be seen at the boarding-house near Hickey's mill.

The mountain opposite, that rises a thousand feet above the station, is
composed of essentially the same rocks as the slide ; but on the west side
of this mountain, from the base far up its slope, there are boulders of lab-
radorite, though diligent search has not revealed a single outcrop. The
marvellous beauty of the finely-striated crystals of the feldspar is shown
by polarized light in the microscopic sections. The vertical walls of the
slide, shown in the heliotype opposite page 69, and Mill mountain, rising
so high and shutting by the slide, give to the place a picturesque beauty,
especially when the setting sun throws a deep shadow over the face of the
slide, and casts across the vast amphitheatre the sombre hue of evening
while as yet the mountain is in the bright sunlight. Leaving the station,
we pass the limit of the porphyrite, and at Stark water-station we strike a
dark siliceous schist. Going east, the rock resembles somewhat a hydro-
mica schist, but still it is a gray siliceous schist, and numerous outcrops
can be seen. The railway cuts it in the east part of Stark, in the corner
of Dummer, and several places for a mile east of West Milan. It has
both easterly and westerly dips, but the easterly dips prevail on the west,
and the westerly dips on the east, so, as a whole, it seems to be a syn-
clinal axis, with minor folds near the middle of the area. These rocks,
except the hard siliceous schists on the west, we have placed in the
Lyman group, which is the upper member of the Huronian. On the
railway, not far from the one hundred and fifth mile-post, we have a

VOL. II. 26

202 STRATIGRAPHICAL GEOLOGY.

hornblendic gneiss, with nodules of epidote and veins of calcite. The
dip is a few degrees west of north, generally at 50° or more, so that it
evidently rests unconformably on the gneiss that follows, extensive out-
crops of which are found near Milan station. The dip of this is usually
north, or a few degrees west of north, near its western limit, but on its
eastern limit, where it varies from north, it is easterly.*

On the steep, precipitous slope that overlooks Dead River pond, in a
rock itself apparently intrusive, there are dykes of a compact, jaspery-
looking rock, which is a compact feldspar; and in this there is a cave of
some little note.

Going down the line of the railway, we find that it cuts a coarse gran-
ite that has plates of black mica three or four inches across, and this
immense mass has disturbed the hornblende gneiss in its immediate
vicinity ; but the position, general dip, and lithological character of this
gneiss are such that it is evidently a repetition of that in Milan, and it is
on the opposite side of the common gneiss. South of the station, at
Berlin falls, we have gneiss in several nearly vertical folds, and this is
traversed by immense "trap" dykes. It is difficult to determine as to
the stratigraphical position of this area. It seems to belong rather to
the remnant of an older formation, than to the rocks in either of the
areas we have described.

At Gorham we have the rocks of the Montalban or White Mountain
series, dark gray gneisses with large plates of mica, having interstratified
with it the granitic gneiss so common in this series. The rocks here, as
well as elsewhere along their western border, have a westerly dip. The
interstratification of the hard gneisses that form so large a part of this
series is better shown here, probably, than anywhere in the whole area
they occupy in New Hampshire and Maine. A short distance above
Shelburne station is the only point where the railway cuts these rocks,

* The facts, stated by Mr. Huntington upon pages 67 and 68, indicate the presence of an anticlinal axis in this
area of Lake gneiss. The Montalban rocks occupy a considerable tract in Dummer and Odell (p. 66), on the
north side of their axis, and the same rocks are spoken of further on along the Grand Trunk Railway. The Lake
gneiss area terminates a few miles north-east from Milan, the farthest exposures of it dipping northerly. These
observations are of importance in determining the relative positions of the Lake and Montalban divisions of the
Atlantic system. It will be noticed that these conclusions do not agree with the statement of J. P. Lesley (p. 194),
to the effect that the fundamental structure is synclinal. As Lesley does not give details, it may be that his syn-
clinal lies entirely to the south-east of Milan, where the structure is of that character. The range of this older
gneiss lies several miles to the north-west of the line of principal White Mountain elevation. Section XI, Plate
VI, Fig. 5, illustrates a part of this route along the railway. C. H. H.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 2O3

and here they are not the most characteristic, but on either side of the
railway there are many outcrops where it can be seen. j. h. h.

Additional Facts.

Mr. Huntington communicates to me in a letter a few additional facts
concerning the rocks along the Grand Trunk Railway in Maine, which
are worthy of preservation in this connection, and are herewith presented.
It appears that the Montalban series prevails over most of the region. At
my request he also states a few facts additional to what we have known
concerning the geology of this region, which he observed in the summer
of 1875, when not emi^loyed in the service of the geological survey.

At Gilead we first find the White Mountain gneiss, where the prevailing dip is east-
erly. The gneiss here has been evidently much disturbed. At Bethel we find granitic
gneiss, and the stratification is very indistinct. At Bryant's pond the gneiss is much
coarser than the common granitic gneiss of the Montalban group. At West Paris there
are immense veins of coarse granite in the gneiss. Half a mile south-west of South
Paris the White Mountain gneiss dips S. 52° E. 18° ; a few rods south-west of this
outcrop there is an impure limestone interstratified with the gneiss, and there are veins
of coarse granite.

At Mechanic falls the dip of the White Mountain gneiss is S. 80° E. 18°. Half a
mile east of the village the dip is E. 20°. It has here, as at the falls, numerous large
veins of granite that contain tourmaline ; and the feldspar is often of a bluish color.
At Danville Junction the dip of the gneiss is quite variable ; sometimes it is N. 10° E.,
but generally more to the east. The inclination is generally not far from 15°. Here
there are veins of both granite and trap. (See Hunt on Granite Veins*) At Pownal
station the White Mountain gneiss dips N. 10° E. 68°, and variable. Half a mile N.
E. of the station the dip is S. 40° E. 25° ; elsewhere the dip is E. 18°.

Mt. Pleasant (Me.) is composed of a granite very similar to that found in the upper
part of the Waterville Slide. The summit at the hotel is composed of a feldspathic
rock, the physical character of which is unlike that of any rock I have seen in New
Hampshire.

In climbing up to King's ravine from Randolph, the rock for the first mile of the
way consists of a peculiar granite, unlike anything described in the report as belonging
either to the Montalban or Lake Winnipiseogee series. It should be referred to the
latter rather than to the former.

There are no ledges at the head of Cutler's river, to the south of Tuckerman's ravine.

Waterville and Sandwich. Israel's mountain is a gneiss. In texture it differs from
both the common and the White Mountain, and it has a northerly dip. Sandwich

* Chemical and Geological Essays. By T. S. Hunt, p. 196.

204 STRATIGRAPHICAL GEOLOGY.

Dome is the White Mountain gneiss, and the dip is N. 15" E. 40°. The ridge north,
beginning at Bald Knob and ending at Noon Peak, is granite. Mt. Waternoo, the
highest point in the Campton mountains, is White Mountain gneiss, and dips N. 20°
W. 35°. On Kimball hill in Whitefield, north-east of Rowland's observatory, there is
a band of intrusive granite that contains fragments of schist often a foot or more in
length.

In Granby, Vt., east of Moose river and a mile north of the road to Victory, there
is also intrusive granite containing fragments of schist with staurolite.

Extension of the White Mountain Rocks into Maine.

In 1873 Mr. Huntington and myself presented to the American Asso-
ciation for the Advancement of Science a joint paper upon the geology
of the north-west part of Maine, which was printed in the proceedings of
the Portland meeting. Its object was to show the relation of the New
Hampshire rocks, in their north-easterly extension, to the fossiliferous
formations approaching as far as the low regions of the Gulf St. Law-
rence. I will state the most important of the facts published by us, and
the conclusions drawn from them at that time. The facts are embodied
in our map showing the relations of the geology of New Hampshire to
that of the adjoining territory. [Plate I.]

The country alluded to is bounded on the east by Moosehead lake, on the north by
the west branch of the Penobscot river, on the west by the water-shed between the
Kennebec and Chaudifere rivers, including the neighborhood of Lake Megantic, on the
south and south-west by the mountain range of which Mt. Bigelow is the culminating
peak.

The fossiliferous rocks of this section were first pointed out by Dr. Jackson, who
studied them particularly in the vicinity of Parlin pond.* He mentions a locality, half
a mile north of Parlin pond, where he discovered a great number and variety of impres-
sions in a bed of graywacke. He speaks of them as the most perfect casts of marine
fossils that he had ever seen. He seems to have been led to the discovery by the
numerous boulders that have been scattered from this formation as far south as the
outer island of Penobscot bay in the mouth of the Kennebec. Dr. Jackson passed
over Moosehead lake ; then he followed Moose river up to the Canada road, which is
some thirty miles from the lake ; thence he went southward, after he had explored the
country northward to the Canada line. In passing up Moose river he crossed the fos-
siliferous strata diagonally. He noticed obscure fossils in the rocks at Lake Brassua,
and these are the only fossils he observed on Moose river, or on the lakes that are
expansions of this stream.

* Third Annual Report upon the Geology of Maine, p. 44, 1839.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 20$

In 1861-62, when engaged on the geological survey of Maine, I had occasion to
traverse the borders of Moosehead lake, then the country westward to the boundary
along the west branch of the Penobscot, and the Canada road from the Forks to the
Chaudifere.* The upper section showed two Huronian areas overlaid by two bands of
clay slates, the latter most likely of Upper Silurian age ; the other, along the Canada
road, exhibited at first strata, most likely Upper Silurian in age (possibly Huronian),
overlaid by a band of Oriskany sandstone, to the west of which appeared, first, granite
ledges, then the Upper Silurian strata, followed by the Huronian again extending into
Canada. f The numerous fossils obtained at the first visit were named by Billings, of
Montreal, who recognized in them characteristic species of the Oriskany sandstone.
Subsequently, the finding of the Fitcoides Cauda-Galli made us believe the representa-
tive of the Cauda-Galli grit appears on Moosehead lake. J

In the hope of gaining some additional knowledge of the rocks of this section, par-
ticularly in determining their extreme limit, J. H. Huntington spent a few weeks, in
1872, in traversing the country from Moosehead lake westward. He found the felsite
of Mt. Kineo in a high ridge to the south-west, on the opposite side of the lake, per-
haps dipping north-westerly. On the west shore of Lake Brassua, probably two miles
from the southern extremity of the lake, there is an outcrop of a dark colored shale ;
and immediately north there is another outcrop of felsite. If we follow the line of the
strike of the felsite of Lake Brassua four miles S. W. of Parlin pond, we find Bald
mountain, with the ridges running W. and N. E., to be composed of a rock similar to
that of Mt. Kineo. So it is possible that the rock may be continuous between these
two points. See Plate IV for a generalized section across these formations.

Perhaps three fourths of a mile above Brassua lake the rock is a ferruginous sand-
stone, cut by numerous joints, and the strata dip S. 20° E. 10°. The fossils are quite
numerous, and some of them very distinct. The following are the genera : Avicula,
Modiolopsis, Orthis, Leptoccelia, FlabellUes, Spirifera, Fiicoid. For the next three miles
the rock is a very hard, light brown sandstone, without fossils. At the mouth of Stony
brook, a point some two miles from Long pond, he found another fossiliferous band of
rock. There the sandstone is compact, but it frequently contains fragments of slate
an inch or more across. Thus it is evident that this rock is newer than the slates on
either side. The dip of the rock here is S. 31° E. 2°. The fossils are not so numerous
as in some other places, but they seem to be more generally distributed through the
rock. This is the only locality where the coral Favosites is found. From this point to
Long pond the outcrop is the same compact brown sandstone that is seen in several
places between the Little Brassua and the mouth of Stony brook. The first outcrop
of rock on the south shore of Long pond contains concretions of iron pyrites, but no
fossils. About half-way up the lake the strata run diagonally across, and there are
several outcrops of fossiliferous rock at some distance from the shore. Six miles from
the outlet on the south shore there is quite an extensive outcrop of rock, and an abun-

* Second Annual Report,-^. ■ii,l,\ZtT,. f/^., p. 283. J/^., p. 331.

206 STRATIGRAPHICAL GEOLOGY.

dance of fossils. The dip of the strata here is S. 20° E. 55°. The sandstone is of a
lighter color than that which is generally found farther east, and the strata dip at a
greater angle. The fossiliferous portion of the rock is more argillaceous than the
non-fossiliferous.

Going south across the strata to Mountain brook, a stream running east from OwPs
Head, there are a few fossils, but rather indistinct. The dip of the rock here is S. 40°
E. 10°. In the south-east corner of Long Pond township, near Mud pond, fossils are
abundant. The dip is N. 3° W. 6°. The rock generally is of a brownish-gray color,
and nearly everywhere cut by joints ; so that where there are no fossils it is difficult to
recognize readily the position of the strata. Taking the fossil locality where the rock
begins to dip north as the middle of the axis, we have, by trigonometrical calculation,
the thickness of 2880 feet for the Oriskany sandstone. The rock north-west of the
sandstone is in general an argillaceous schist, and dips toward the sandstone, with little
or no unconformability. If we follow Moose river above here, we shall find a granitic
gneiss. The first outcrop is on an island near the outlet of Wood pond. The fossils
from Parlin pond are Strophoinena magnifica. Or this musailosa, Rhynchonella oblata,
Rensselceria ovoides, Leptocalia flabelUtes, Spirifera ar recta and pyxidata, Modiolopsis,
Cyrtodonta, Avicula, MurcJiisonia, Orthoceras, and Dahnanites epicrates.

The rocks on a section from Lake Megantic to Lexington are as follows : At the
north end of the lake there is a dark- gray arenaceous schist that frequently contains
iron pyrites. On the west side of the lake, and south of Victoria river, there is a
wrinkled argillaceous schist, with a fossil brown slate having small cavities filled with
a yellowish-brown powder. The dip is S. 45° E. 70°. These rocks are referred to the
Upper Silurian by Sir William E. Logan, and they extend down the Chaudifere river to
St. Francis. South-west we have found them in Ditton and on the boundary of New
Hampshire. Their eastern limit is near the head of Perry Stream. On their southern
extension they pass into mica schist. Following the road parallel with the lake six
miles from Lake Megantic, the rock changes, and we have green chloritic schists con-
taining light green epidolitic nodules. The rock here dips N. 35° E. 36°. Farther up
the lake we have fine, dark gray sandstones. These rocks were examined by Sir Wm.
Logan on the lake shore, and by him they were referred to the Quebec group, and
were supposed to underlie the wrinkled argillaceous schist just described. This seems
quite probable, from their relations elsewhere. We have the same succession of rocks
in New Hampshire, in the vicinity of Connecticut lake, and name the first Coos group,
the second Huronian. Near the boundary of Quebec and Maine, and forming the
water-shed between Chaudifere and Dead rivers, we have a band of granite, probably
eruptive. Following the granite, and extending along Dead river for four or five miles,
we have a granitic gneiss, the strata of which are apparently horizontal. The high
mountain ridge at the Chain lakes is an eruptive granite ; and this is followed near the
outlet of the lake by a fine-grained gneiss that dips 67° and 70° W., and probably
extends two miles down the river. We then have for a quarter of a mile a granular
talcoid schistose rock, that dips 80° N. 20° W. This is followed by an impure serpen-

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 20/

tine of a very dark color, often asbesliform in the joints, and appearing to form a syn-
clinal axis. It is followed on the south-east by a granular crystalline rock somewhat
coarser than that on the north-east, but otherwise similar. This rock is so cut by joints
that it is impossible to determine the dip, though the strike corresponds with the gran-
ular crystalline rock north-east of the serpentine.

Leaving the river and following the old road, the next outcrop is a dark green crys-
talline rock, succeeded by quartzite that dips 63° S. 20° E. This is followed by a
breccia composed of greenish slate, quartzite, and serpentine, and also what appear to
be reddish grains of felsite. The breccia seems to be composed of rocks found on
either side of it. It is followed on the south-east by a quartzite that dips 75° S. 30"^ W.
At Eustis village, extending a mile north-west and three and a half miles south-east,
there is a band of tender fissile slate, generally of a greenish-gray color, but having
bands of light purple ; and south-east of the village are bands of quartzite. This slate
forms a distinct synclinal axis. On the RIagalloway river we have granular schistose
rocks, quartzites, serpentine, and slate. The similarity of these to those on Dead river
makes it quite probable that the latter are a continuation of the former. Between
Eustis village and Mt. Bigelow there is a greenish chloritic rock that seems to pass
into porphyritic gneiss. This rock occupies a large area in Dead River plantation and
Flagstaff. Since a similar rock was seen in Range 6, Lot 3, and north-west at Attean
and Wood ponds, a continuous band may extend thirty miles northward. There is a
striking similarity in this rock to one found in Northumberland, N. H., and southward.
Here, as at Littleton, N. H., there is a band of Helderberg limestone containing corals
that are remarkably distinct. The rock where the fossils are most abundant outcrops
on an island in Flagstaff pond. On the west peak of Flagstaff mountain there is a
band of limestone, but the fossils are very obscure. South of the green chloritic gneiss
there is a mica schist or imperfect gneiss that resembles very closely the White Moun-
tain series. On the west peak of Mt. Bigelow the dip is 50° N. On the ridge extend-
ing from Mt. Bigelow east, where the road passes over it in Range 11, No. 2, the rock
is mica schist. It dips 60° N. 5° W., and carries an abundance of small crystals of
andalusite. These rocks rest on a porphyritic gneiss that outcrops a few rods south of
the height of land. The gneiss resembles the rock of the basin north-west in the
valley, and is followed on the south in New Portland by a granitoid gneiss that resem-
bles very closely that associated with the gneiss in the vicinity of the White Mountains.

Adopting the conclusions derived from our study of the rocks in northern New Eng-
land, we think the porphyritic gneiss south of Mt. Bigelow is the oldest of all the rocks
enumerated. This area is represented in the north-east corner of the map, page 512,
Volume I. The gneisses of Mt. Bigelow and the ridges eastward abound in crystals
of andalusite, and appear to belong to the White Mountain series, and to rest upon the
porphyritic variety. The series of chloritic and talcoid schists, quartzites, and serpen-
tines appears to be still more recent, and to be allied to the Huronian system. The
granite and gneiss from the lake outlet on the east to the Megantic basin on the west,
may be older than the Huronian upon both flanks.

208 STRATIGRAPHICAL GEOLOGY.

Conclusions.

Four important conclusions may be drawn from the distribution of the
formations in north-western Maine, when compared with the rock-expos-
ures in New Hampshire and elsewhere.

1. The Oriskany sandstone reposes gently upon Eozoic gneisses, the
first bearing scarcely more traces of alteration than the corresponding
group in New York, while the second seems to have been metamor-
phosed and elevated before the Devonian formation was deposited. No
further trace of this group has yet been found towards the White Moun-
tains. It has been followed through Maine from one hundred and fifty
to two hundred miles, and similar rocks are described in Nova Scotia by
Dawson. It can, therefore, no longer be maintained with reason that
these strata pass into New Hampshire in a metamorphosed condition.
Furthermore, since the Oriskany and Helderberg formations are so dis-
tinctly f ossiferous in immediate juxtaposition with the crystalline strata,
it affords a presumption that the latter groups have not been altered
from any other Paleozoic sediments.

2. The Oriskany is several times thicker than its extension in the
interior and farther south in Pennsylvania. The greatest thickness men-
tioned by H. D. Rogers is five hundred and twenty feet, about one fifth
its dimensions in Maine. The greatest observed thickness in New York
is only thirty feet.

3. The discovery of nev/ localities of Helderberg limestone indicates
a wide-spread submergence of eastern America, in Upper Silurian and
Middle Devonian times, of nearly fifteen hundred feet. These fossils
have been detected at Bernardston, Mass., Lyman and Littleton, N. H.,
perhaps Orleans county, Vt., Montreal, Lake Memphremagog, and other
localities to the north-east in Quebec province, Eustis, Flagstaff, and
Spencer mountain, in the field described above in Maine, and still greater
developments in the northern part of Maine, too extensive to be specially
mentioned ; — hence,

4. There must have been, subsequently to the Helderberg, a period of
elevation to bring New England to essentially its present condition. Pos-
sibly this epoch may be indicated in the later elevating force seen upon

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 20^

Mt. Washington. The highly incHncd PIcldcrberg strata at Littleton
and Owl's Head, P. O., certainly bear witness to the exertion of a pow-
erful elevating agency.

LABRADOR SYSTEM.

There seem now to be seven areas of labradorite rocks among the
White Mountains. Some that have hitherto been supposed to consist of
this mineral prove to be another variety of feldspar. The genuine areas
are the following: i, upon Norway brook, and 2, upon Sabba Day brook,
the opposite sides of Tripyramid mountain in Waterville; 3, on Mt.
Washington river; 4, Loon Pond mountain, near Pollard's in Lincoln;
5, south end of the Lafayette range; 6, Bean's Purchase; 7, Mill moun-
tain, Stark. I will describe each of these areas in turn, so far as known.

The older geologists regarded all the crystalline rocks as those first
formed, or "primary." The granites were considered as remains of the
original crust, cooled down from the condition of intense fusion ; and the
gneiss, mica schists, etc., resulted from the action of eroding agencies,
tearing off fragments of the granites and depositing them in the lower
areas. These unstratified and stratified rocks have also been styled
Azoic, from the supposed absence of life in these early periods. Only
lithological names had been applied to the different Azoic rocks till
1855,* when Sir William E. Logan and T. Sterry Hunt proposed that
the Azoic formations in Canada beneath the Potsdam sandstone should
receive local appellations ; and they accordingly separated them into two
groups, calling the older Laiwcntian and the newer Huronian. These
terms expressly excluded the crystalline rocks of New England, which, by
many authors, had already been considered to be of Paleozoic age. So
early as 1845 Logan had perceived that the gneiss of Canada, afterwards
termed Laurentian, could be divided into two groups, dei^endent upon
the presence or absence of beds of limestone, and in 1857! suggested
that such a division would probably be found desirable. The suggestion
was not carried out, since the studies of Dr. Hunt, from 1852 onwards,
upon the feldspars, led him to question the appropriateness of this classi-
fication of the Laurentian, because the lime-feldspars seemed of greater
importance in the distinguishing of new groups. In the report upon the

* Esquissc Geoiogii^ue dii Canada, f Proc. Aincr. Asso. Adv. Set., Vol. XI, Part II, p. 47.
VOL. II. 27

2IO STRATIGRAPIIICAL GEOLOGY.

geology of Canada for 1863 * great vertical thicknesses of the Laiirentian
gneiss are distinguished mineralogically from the others by the presence
of triclinic feldspars, and the rocks termed anortJiosites. I understand
that there are scarcely any orthoclase gneisses interstratified with the
anorthosites. Later in the same volume certain facts are stated, render-
ing it probable that the anorthosite series unconformably overlies the
gneiss having beds of limestone in it.f The formal proposal of this sub-
division is presented in the atlas accompanying this report, issued in 1865,
where the anorthosite group is distinguished as the Upper Lmirentian or
Labrador series, and the other the Lower Laurentian. The nomencla-
ture of this atlas is based upon further exploration. Had this not been
satisfactory, the distinction would certainly not have been delineated in
the atlas. The evidences of unconformity consist in the concealment of
beds of limestone by the upper rocks covering them, and the change of
strike. The testimony of Mr. James Richardson, to the relations of the
Lower and Upper Laurentian on the north shore of the St. Lawrence, in
1869, confirms the reality of the division. He represents the dip of the
Laurentian to be nearly vertical, with a north and south strike, while the
labradorite rocks dip at comparatively moderate angles, with a strike
nearly east and west.^ Seven areas of labradorite rocks outside of New
England are represented upon Plate I of this volume, — five north of the
River St. Lawrence, one in Newfoundland, and one in New York. It is
spoken of as occurring in Alabama, in the recent report of Dr. Eugene
A. Smith, and much of the mineral occurs at other localities along the
Atlantic range, as in North Carolina and Pennsylvania. None of the
Labrador areas, whether in America or Europe, have yet been carefully
studied stratigraphically, so that we have not the means of knowing their
thickness. The lines of iron ore and other foreign minerals better agree
with the idea of stratification than to suppose the masses are eruptive.
In the study of New England rocks, the labradorite aids us greatly, since
most geologists are prepared to accept it as indicating formations of
Eozoic date; and, if these triclinic feldspar layers rest upon strata for-
merly thought to be Paleozoic, they render it probable that both the un-
derlying and contiguous masses belong to very ancient systems.

* Ceol. Survey of Canada, Report for 1863, pp. 22, 23, 478, and 586. \Id., p. 839,
Xld., Report 1866-69, p. 306.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 211

The mineral labradorite was found at Waterville, among the mountains,
the first of any locality in New Hampshire. The history of its discovery,
and the diverse opinions expressed concerning the rocks, especially by
Professors Dana and Hunt, have been already stated in Volume I, page
37, et scg., so that we may confine our descriptions at this time to notic-
ing the occurrence of the rocks in nature, with whatever light may be
derived from the controversies respecting them. The first two areas
mentioned occupy the south and north flanks of the mass of mountains
in Waterville called Tripyramid.

Southern Area of Labradorite in Waterville.

In the east part of Waterville three pyramidal peaks attract the atten-
tion of observers, from whichever side they are seen, A fourth makes
its appearance when the pyramid is viewed attentively. Mr. Morse's pro-
files, taken from Mts. Chocorua, Pequawket, Tremont, etc., exhibit well
the shape of the mass ; and the topographical aspects are represented,
also, upon the special White Mountain map. Tripyramid is washed on
the west and south by the head waters of Mad river, and on the north
and east by the tributaries of Swift river, notably Sabba Day brook.
Bond figures the peaks without names, but with the altitudes from south
to north of 4100, 4100, 4200, and 4000 feet respectively, with a course of
about N. 10° W. Guyot mentions but one altitude — taken by a pocket-
level — of 4086 feet. Upon his map, published in 1 860 from observations
made six or eight years previously, Guyot calls the mountain Tripyramid.
The Grafton County map, published also in 1 860, gives the name of Pas-
saconnaway to the same elevations, and the first publications relating to
its geology, by Prof. Perkins and myself, used the latter name. Only this
last summer I ascertained definitely that Messrs. Greeley and Mason first
proposed to call these peaks Passaconnaway in i860, without knowing of
Guyot's suggestion. In our present report the name Passaconnaway is
applied to a peak south-easterly from Tripyramid in Waterville, called
North Whiteface by Guyot; and later authors seem to approve of this
nomenclature, so that it will be retained by us henceforth. These expla-
nations will prevent any misunderstanding hereafter as to the peaks called
by us Tripyramid and Passaconnaway.

The notable storm, ending October 4, 1 869, gave rise to a remarkable

212 STKATIGRAPHICAL GEOLOGY.

freshet upon the south-western slope of the most southern of these pyra-
mids. The mountain side seems to have been covered by spruces grow-
ing above loose blocks carpeted abundantly with moss, very much as is
common all over the White Hills wherever the climate permits temperate
vegetation to flourish. No valley furrowed the slope ; and it seems diffi-
cult to understand why the waters should have accumulated so enor-
mously at this point, and nowhere else in the neighborhood, if we may
judge by the effect produced, especially since the bare mountain side
exposed at this time has rendered the area conspicuous as a landmark
fifty miles away. It were easy to imagine that some atmospheric dis-
turbances had collected the waters naturally dispersed in an area having
the diameter of a mile, and discharged them in a narrow stream upon the
forest beneath. Clouds are sometimes said to "burst," when their con-
tents are poured very quickly into some limited area, most usually when
a tornado or rapidly-formed nimbus flits by ; and something of that na-
ture, though not approved by the best meteorologists, will best explain
the phenomena displayed in Waterville during this never-to-be-forgotten
storm.

Almost immediately after the storm this locality was visited by a party
consisting of Prof. G. H. Perkins, ph. d., of the University of Vermont,
Rev. M. T. Runnells, of Sanbornton, and Charles Cutter, of Campton.
Prof. Perkins wrote a description of the changes wrought in the country,
and published it in the American Joimial of Science (ii, vol. xlix, p. 158).
As he made careful estimates of distances in the upper part of the moun-
tain, I will use his figures in the paragraph which follows.

The sliding commenced about forty rods from the summit, a little one
side of the highest point. The beginning of the bare earth is only a rod
in width. The breadth increases gradually for fifty or sixty rods. For
the following seventy rods down hill it widens rapidly, attaining at one
hundred and thirty rods distance a width of twenty-five or thirty rods.
Thirty-six rods lower, the breadth is seventeen rods. The course is nearly
straight to this point, — one hundred and sixty rods, — where it begins to
curve towards the north-west instead of continuing south-westerly, and
eighty rods below is what Prof. Perkins regarded as a termination of the
slide. The waters excavated a gorge through the boulder-clay or hardpan
of the country, after passing the Elbow, often twenty-five feet deep, the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 21 3

material being almost as firm as solid rock. The whole course thus far
mentioned is two hundred and forty-six rods, of a general fusiform out-
line, with the lower end curved to one side. The inclination of the debris
is often as much as forty-five degrees, perhaps higher for a dozen yards,
and generally somewhat less. The underlying ledges appear in two or
three i^laces, but do not exhibit any marks or scratches made by the slid-
ing mass.

The curve at the bottom of the hill is nearly a right angle, and was
determined by the configuration of the land, for, directly in the way of
the slip, there is a low ridge covered by the universal forest. Were the
phenomenon a true slide, the materials would have been arrested by this
obstacle. But no more earth lies before this obstruction than along any
part of the two or three miles distance of the steepest descent below.
The forest must therefore have been torn up by a prodigious freshet, —
trees, earth, and rock-fragments mingling with the water, as if all a liquid
mass, winding through the curved valley of a stream, and excavating a
deeper channel below the turn in its direction. In a clearing of fifty acres
at the base of the mountain, called "Becky town," great piles of rubbish,
rocks, and trees accumulated, while only earth was transported further.

For nearly two miles below the Elbow mentioned above, the current
descended rapidly, occasionally depositing gravel in protected nooks,
which, with their sloping surfaces, may be called terraces. Quite high
up is an interesting excavation in the form of a notch, where one side is
long, sloping gradually, and the other steep and short. Half-way down
the stream, — which may appropriately be termed Norway brook, on ac-
count of the name "Norian," at one time applied by us to the formations
traversed by it, — the water falls precipitately over a ledge of the dark lab-
radorite rock. Elsewhere the valley is like that of any mountain torrent.

This locality is easily accessible. During the summer a stage runs
from Plymouth to Greeley's hotel in Waterville, a distance of twenty
miles. From Greeley's the first of the labradorite ledges is less than
two miles, over a well-defined foot-path, which passes near a picturesque
cataract. Mr. Greeley can direct visitors to these rocks.

In following Mad river up from Greeley's saw-mill, no ledges appear
for a great distance. In the neighborhood of "Swaseytown," a small
clearing near the mouth of Norway brook, there are abundant outcrops

214 STRATIGRAPHICAL GEOLOGY.

of porphyritic gneiss. The stream has cut down several feet into the
ledge, and there is something of a fall here. Dykes of trap traverse the
gneiss. The dip is south-westerly. Passing up the stream, in the neigh-
borhood of a mile, we are brought to "Becky town," the base of the slide,
where the great piles of rubbish first become conspicuous in making the
ascent. A few rods above is an exposure of the same rocks with those
seen at the falls, dipping 80° S. 10° W. The strata are indicated by folia
of mica and a little of a dark hypersthenic mineral, often forming nodules.
There are jointed planes, also, with a dip westerly of 25°. The feldspar is
nodular, the crystals not being so perfect as is common in this formation,
or as may be seen upon Cascade brook to the south (p. 103). Between
Norway and Cascade brooks there seems to be an anticlinal axis in the
porphyritic gneiss. At first I was satisfied that this rock was gneiss,
but did not recognize its true place with the porphyritic group. Subse-
quently I referred it to the "trachytic" or Albany granite, but a reexami-
nation in 1875 shows that it belongs to the oldest of our formations, and
is distinctly stratified, traversed by trap dykes and narrow banded veins
of quartz. These exposures do not occupy more than two hundred feet
of distance.

A few rods up Norway brook appears the first ledge of the ossipyte.
Its junction with the gneiss is concealed by drift. For about a mile
similar ledges occur, some exposures being sixty or seventy feet long.
Considered as an isolated case, it is difificult to determine the planes of
stratification, since two prominent sets of jointed planes exist, either of
which might be taken for strata. One set dip about 20° northerly, and
are the most numerous. The other dip about 75° westerly. More defi-
nitely, the following are the supposed strata dips seen in ascending:
about 20° to N. 26° W., N. 86° W., N. 34° E., and N. 46° W. The joints
have these strikes, N. 22° W., N., and S. Analyses of both the labradorite
and chrysolite, which form the constituents of the ossipyte, have been
given in Volume I, pages 37-40, by Hunt and Dana. It appears that
small portions of magnetite and biotite arc also present in the rock.

SlENITE OF TrIPYRAMID.

The ossipyte is abruptly succeeded by the gray rock called sienitic,
being sometimes labradorite, with hornblende and some mica, then ortho-

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 21 5

clase, labradoritc, and mica, with scarcely any hornblende. The line of
junction is irregular, averaging the course N. io° E., being sometimes N.
yS° W., while the dip of the plane of separation is about 85° westerly.
Some of this feldspathic rock has been injected into irregular cavities of
the ossipyte. The irregularities of these veins are shown in Fig. 18.
The length of the vein there represented is thirty feet, the greatest
width being four feet. The general impression is, that the sienite was
an eruptive rock, cutting nearly vertically across the ossipyte.

Perhaps an eighth of a mile above this junction the interesting assem-
blage of coarse crystals of whitish labradorite, hornblende, titanic iron,
mica, and epidote (see analysis, p. 40, vol. i) occurs at the Notch. These
ledges disintegrate very rapidly. Large nodules of the sienitic rock less
liable to decomposition are scattered through the mass ; and there are
geodic cavities containing orthoclase, albite, quartz, and rarely stilbite.
The Notch is produced by the erosion of a ferruginous band, resembling
a stratum, and dipping both E. 25° S. and E. 25° N. Above the Notch, as
far as the Elbow, there is a recurrence of the finer-grained sienite, contain-
ing geodes and feldspathic veins. At the Elbow there is a somewhat dif-
ferent mineral combination, extending to the top of the pyramid. Quartz
is rare ; but there are two kinds of feldspar. Mica is abundant, and some
specimens show hornblende. The same minerals occur in the geodic
masses as below, also, actinolite, amethyst, and others yet undetermined.

A light-colored feldspar, from a reddish-tinted variety of the "sienite,"
gave to Prof. C. A. Seely, silica, 59.2; alumina, 28.8; iron oxyd, trace;
lime, 7.40; soda, 8.54; potash, 0.6. In this case the silica, alumina with
iron oxyd, and lime were determined first. Afterwards, the alkalies were
determined separately from a different sample of rock. Judging from
these results, the feldspar corresponds very well in composition with an-
desite. The type-mineral of this species is said, in Daiids Minn-alogy,
to come from a "sienite-like rock" in the Andes. Some analyses of ande-
sites from Chateau Richer in Canada, by Dr. Hunt, agree well with this.
The red feldspar associated with the andesite in this rock gave to Prof.
Seely, silica, 57.6; alumina and iron oxyd, 24.6; lime, 3.2. It seems,
therefore, to be related to the same species rather than to orthoclase,
but it is not well defined.

Towards the top of the slide and the mountain there is considerable

2l6 STRATIGRAPHICAL GEOLOGY.

hornblende, with less mica, and the rock is of a reddish cast. Specimens
precisely like these came from the north peak of Tripyramid. On the
north slope of this peak there is a recurrence of the more grayish variety
found between the Notch and the Elbow. In this a black mica excludes
most of the hornblende. Near the head of Sabba Day brook the coarser
white aggregate containing epidote, etc., is found again, though our speci-
mens do not indicate the presence of that particular mineral. On the
ridge north of the north pyramid are gray sienites with labradorite, re-
sembling those immediately adjacent to the ossipyte on Norway brook.
The rocks from the west side of the ridge east of Tripyramid correspond
better with the coarser white rock of the Notch. From this inspection
of specimens, taken from almost a section line up Norway brook to North
Tripyramid, and thence to the labradorites on Sabba Day brook, it ap-
pears that the different varieties of this sienitic rock correspond well with
each other, very much as if the mountain were a synclinal axis, consist-
ing of four leading varieties of strata, with only slight inclinations. The
contact of the ossipyte with the sicnite seems to show clearly the cutting
of the former by the latter, while this stratiform arrangement of the dif-
ferent varieties of sienite is analogous to the mutual relations of the Con-
way, Albany, and Chocorua granites. Until further advices, this sienite
must therefore be regarded as an eruptive rock.

There is but one other New Hampshire locality known where a similar
rock appears. That is in the adit of the Jackson tin mine. I am not
sure that the ledge crops out at the surface; but the fragments brought
out by excavation reveal an abundance of sienite, which cuts the schists,
in company with the Albany granite. The principal part of the rock is
a coarsely crystalline labradorite, with considerable hornblende and ortho-
clase crystals in small amount. Quartz is scarce, as at Tripyramid. Mr.
Huntington states that Mt. Pleasant, in Maine, one of the outlying peaks
of the White Mountains, carries the same rocks as Tripyramid. The
area of Pleasant is about the same with that of Tripyramid, and it is given
on our general geological map.

While the sienite is of later age than the Labrador formation, we can-
not yet ally it with the sienites of Gunstock and Exeter. Its nearest
analogue is the sienite of Frankenstein cliff and Mt. Whiteface, which
are for the present placed with the Chocorua granite.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, 2\^

Labradorite Area north of Tripyramid.

Mr. Huntington discovered fine exposures of labradorite and the re-
lated formations in ascending that tributary of Swift river called Sabba
Day brook. Near the mouth of the stream there is a cataract falling
over Conway granite, which is the common rock of the country. The
same appears a mile higher up. It also occurs on Downs's brook, another
tributary of Swift river, running very nearly along the line between Water-
ville and Albany. The Albany granite was not observed here, possibly
because we had not learned the importance of distinguishing it at the
time of the visit. But higher up Sabba Day brook Mr. Huntington found
compact labradorite in place, apparently devoid of chrysolite, and frag-
ments whose cleavable crystals displayed the play of colors usually seen
in this species. Higher up the mountain (the north Tripyramid) the
sienitic rocks of the slide reappear in the same order as in the ascent of
Norway brook, apparently cutting the labradorites. Farther south the
labradorite passes into a breccia apparently overlying gneiss. It is proba-
ble that the Albany granite joins the labradorite on the north, since speci-
mens apparently referable to it came from the Flume brook, about two
miles to the north of Tripyramid. The small area of gneiss south-east
has been mentioned upon pages 131 and 133. Otherwise, most of the
rocks on the east belong to the Conway granite series. On the south
and south-west this Labrador area is flanked by porphyritic gneiss. Fig.
19 will show the position of the ossipytes, compact lime-felsites, and the
sienites between Beckytown and Swift river, passing over Tripyramid,
and their supposed relations to the adjacent porphyritic gneiss and Pemi-
gewasset granites.

Labrador Area upon Mt. Washington River.

Upon pages 125-127 the Montalban rocks upon the Mt. Washington
river are spoken of in connection with labradorite. This is an important
locality, as it shows the relations between the Montalban and Labrador
systems. The details of the former series have been already given, with
as much precision as possible. The latter area extends only about a mile
along the river. Its width is not ascertained ; but G. N. Merrill, of Jack-
son, assures me he has seen this rock on a tributary stream midway

VOL. II. 28

2l8 STRATIGRAPHICAL GEOLOGY,

between Giant's Stairs and the Mt. Washington river, thus giving it an
extension of over three miles in a south-easterly direction. At the north
end there is an excellent exposure of the contact between the two forma-
tions. It is upon the west bank of the river, two or three hundred feet
away from the water, and fifty or sixty feet high. The gneiss is the
slightly porphyritic variety of the Montalban schists, dipping 80° N. 80°
W., or towards Mt. Clinton, and much disturbed by trap dykes. This
position is rendered plain by the stripping of the hillside for more than a
hundred feet by a brook. The line of the brook is about twenty-five feet
distant from the labradorite rock, with the dip of about twelve degrees
south-westerly. The actual junction is covered by earth of little thick-
ness. Were one not satisfied with the way in which the formations unite,
it would be very easy to observe the actual contact after a little labor ex-
pended upon digging. On descending to the river, and over its whole
course, the dip of the labradorite is not far removed from horizontal.
Next the schists, at the lower end, the masses lie horizontally; then, a
few rods above, there is a short synclinal, with the dip of 30°, and after
that a nearly horizontal disposition to the northern extremity, where the
dip is south-westerly. Fig. 20 shows the junction of the two rocks at
the upper end. Perhaps an eighth of a mile above the lower extremity of
the formation, there is a seam somewhat resembling a stratum, with a
north-west strike, and standing vertically. The rock adjacent on the
south is a flinty gneiss, dipping 60° N. 40° W.

A reexamination of the lower portion of this outlier in 1875 revealed
nothing new of any importance. All the ledges are much jointed, and
there is a strong contrast between the massive blocks of labradorite and
ossipyte and the gneissic rocks adjacent.

The stratigraphical relations of the two formations seem very simple.
The labrador rocks lie unconformably upon the upturned edges of the
Montalban gneisses. The discordance varies from forty-five to seventy
degrees. In going up the stream, it is easy to see that the labradorite
rocks rest upon the gneisses, as both dip in the same direction; and
when the upper limit is reached, the dissimilarity between the two is
marked fully as strongly as is indicated in the figure. It may be thought,
because the labradorite lies in a deep valley, with mountains of gneiss
upon both sides, that it must perforce possess an anticlinal structure, and

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 219

underlie the latter. In many regions the valleys are of anticlinal origin,
and, if these rocks occurred in such a district, the view might be tena-
ble. It does not seem to us, — for reasons to be stated elsewhere, — that
such a law of connection between stratigraphy and topography is of
universal application, and, furthermore, the observations of the actual
dips in the neighborhood are against that view. In coming up the river
from the Saco valley, after leaving the granite, the first dips are south-
easterly. Not very much is seen of this dip, since the strata possessing
it are covered by granite, but enough appears to make its occurrence
certain. But the north-westerly dip is common beyond, so that an anti-
clinal axis certainly occupies the valley below the labradorite, in agree-
ment with what is often the case in valleys elsewhere. Our studies lead
us to believe, also, that the range to the north-west, embracing the Web-
ster-Washington range, possesses an anticlinal structure. The details
mentioned previously concerning the strata up the streams to Mts. Clin-
ton and Pleasant show a prevailing north-westerly dip, with local varia-
tions. Thus, as advised at present, the outlier of labradorite seems to
occupy the country between two anticlinal axes, not necessarily the mid-
dle or synclinal line, but the upturned edges. In either case there would
be a great want of conformity between the two groups, the uppermost, or
the Labrador system, being the younger formation.

The prevailing variety of rock in this basin is ossipyte. Prof. B. T.
Blanpied found the labradorite, when carefully separated from the chryso-
lite, to contain silica, 51.50; alumina, 25.90; peroxide of iron, 5.00; lime,
14.29; soda, 2.95; potash, .50 — total, 100.14. These results correspond
essentially with the analyses of the same mineral from Waterville (Vol. I,
pp. 37 and 39). The grains of magnetic iron were also observed. In
lithological appearance there is little difference between the localities,
save that the labradorite crystals from Mt. Washington river are better
characterized than those from Waterville.

Many of the layers contain an abundance of hornblende, much more
so than at either of the Waterville areas. Large boulders of chryso-
litic sienite are common in the river, but their source has not been ascer-
tained.

The locality may be reached easily, though it is desirable that those
who visit it be prepared to spend a night in camp. I have reached it by

220 STRATIGRAPIIICAL GEOLOGY.

the way of the tributary stream flowing down between Mts. Franklin and
Pleasant, between Mts. Clinton and Jackson, and also by ascending from
the Saco. No path has yet been marked out for horses, but the road is
easy to find, by simply following a watercourse. It is about six miles
from the Saco, six from Mt. Washington summit, three from Mt. Pleasant,
and four from the Crawford house, following up the bridle-path to Mt.
Clinton, and thence passing down the stream to Mt. Washington river.
When the latter route is taken, the explorer must remember to walk up
stream as soon as he has reached the Mt. Washington river.

Other Labrador Areas.

The remaining localities of labradorite have not been much explored,
and are quite limited in extent. In passing from the south end of the
Lafayette range in Lincoln to the road near Walker's falls, I found an
exposure of this rock, which gave, when examined, results almost identi-
cal with the analysis of the labradorite from Mt. Washington river. Prof.
Blanpied found in it, silica, 52.01,; alumina, 26.60 ; iron oxyd, 4.20; lime,
13.30; soda, 3.50; potash, .65=100.26. The rock is a dark, compact
mass, not composed of different minerals, as at the other localities, but
has crystals of labradorite scattered through a dark paste of the same
material, with an occasional bit of quartz. As far as from the spur at
the north base of Mt. Lafayette, to where the range first falls off rapidly
towards Mt. Liberty, a distance of five miles, there is a narrow range of
dark, compact felsite, apparently resting almost horizontally upon the
Albany granite, never more than two or three hundred feet wide; and,
as the specimen analyzed did not differ greatly in appearance from the
great mass of the rock, I had supposed the whole mass consisted of lab-
radorite, in the report for 1871, page 17. Specimens from the summit of
Lafayette, obtained in 1875, are evidently not labradorite; but the rela-
tions of the rock, at the south end of the range, to the rest have not been
reexamined. Boulders of labradorite occur at one or two places on the
west flank of the Lafayette range, so that it is likely there will be found,
upon further examination, a considerable exposure of the Labrador sys-
tem. Still, it is an open question whether the dark, compact labradorite
felsite may not be igneous in origin, and be connected closely with the
orthoclase felsitcs, of which the greater part of the range consists.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, 221

At Loon Pond. A similar rock crops out a little east of Loon pond,
seven miles distant. The area is probably a quarter of a mile in length.
The specimen brought from there agrees closely with that just described
from the south end of the Lafayette range. Between Loon pond and
the most southern end of the orthoclase felsite on Mt. Flume, the dis-
tance is four and a half miles, so that the last named area is entirely
isolated from all related rocks. The mountain east of the pond is com-
posed of Albany granite.

In the report for 1871 the orthoclase and labradorite fclsites were re-
garded as intimately associated together, and forming parts of one sys-
tem. As some doubts have been expressed by geologists upon this
point, I will now describe them separately, and represent them as dis-
tinct from each other upon the map. The latter will be spoken of under
the head of Porphyry. A few of the small areas, formerly thought to be
labradorite, prove now to be orthoclase. Such are the rocks on the west
side of Mt. Tom, and the first peak north of Mt, Andalusite near the
Crawford house. Rocky Branch in Bartlett, and the west side of Sable
mountain in Jackson. There is labradorite in a breccia from the last
named locality, and also from the head of Sabba Day brook in Waterville,
and upon Little Deer brook in Albany. It was thought at one time, also,
that certain portions of the Chocorua granites contained lime-feldspar.
All these specimens will be studied more carefully hereafter; and, in the
part of the report devoted to mineralogy and lithology, the reader will
find their characters stated with much precision. The necessity of devot-
ing our whole time to the general description of the formations has pre-
vented us from giving the proper amount of attention to lithology, that
is really demanded as preliminary to stratigraphy. There can be no mis-
take as to the localities, since the catalogue and map, at the close of this
chapter, will make all the positions plain.

Labradorite in Beans Purchase. Mr. G. N. Merrill, of Jackson, informs
rae that he has seen labradorite in rock masses upon Thompson's brook,
on the east side of Ellis river, in Bean's Purchase. I understand it is
situated on the west slope of Wildcat mountain, some three or four miles
back from the Ellis river. It is in the midst of the Montalban series, like
that on Mt. Washington river; but we have no facts in respect to the
position of either the labradorite or gneissic strata.

STRATIGRAPHICAL GEOLOGY.

PORPHYRY.

The term porphyry has long been used to denominate rocks with a
homogeneous, compact, or earthy base, through which are disseminated
crystalline masses of the same character with the matrix, and formed at
the same time with it. The porphyry of the White Mountains seems to
be allied to a common orthoclase feldspar porphyry, orthophyre, or petro-
silex. In the annual reports it has been termed felsite, and grouped with
the Labrador system. The localities of this rock are mostly far away
from settlements, so that it has not been easy to examine its relations to
other formations. The rock has a tendency to weather into pinnacles or
sharp ridges like the Twins, Mts. Liberty, Flume, the Lafayette range,
Starr King, etc.; and the decomposition extends so deeply into the ledges,
that one may obtain from a hasty visit to a mountain a very inadequate
idea of its composition. Reserving all special details of nomenclature
and composition to the chapter on lithology, we will now be content to
describe briefly the areas where it occurs.

As porphyry occurs both as an igneous and a stratified rock, it is dififi-
cult to know to which class to refer this member. Our first impression
suggested the idea of stratification, based upon the horizontal arrange-
ment of the masses. Of late some facts have been brought to our notice,
seeming to imply protrusion through strata, and lateral expansion by an
overflow. This theory would explain the horizontal situation of so much
of the rock, while it is a fact that no other kind of igneous rock has been
found to assume the position of an overflow in New Hampshire.

It may be that the porphyry mountains of New Hampshire should have
been mentioned in the chapter on Scenographical Geology, as constitut-
ing a distinct type of rock sculpture. The peaks are somewhat like the
isolated granitic summits, yet a practised eye would never confound the
two together. The latter are usually more rounded: the former might
easily constitute a pinnacle. The porphyry summits remind one of a
triangle, with one slope much steeper than the other. Sometimes two
summits are connected together by a surface line, like a catenary curve,
as seen from a distance. Other areas, like the Twin mountains and Lafay-
ette arc disposed in the form of long, narrow ridges. Mt. Carrigain might
easily be confounded with a granitic cone, at a distance, but not so the

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 223

sharp peak to the north of it before reaching the " Notch," or Mt. Lowell.
All these mountains are full of precipices, often inaccessible. In the
Pilot range so much debris has accumulated about the porphyry peaks,
that the ledges cannot be seen except very near their summits; and it is
for this reason that it has been so difficult to learn the relations existing
between this and the adjacent Huronian.

There are a dozen different areas of rock in the White Mountain dis-
trict referable to this division, which I will describe under the following
names: i. Lafayette range. 2. Twin Mountain area. 3. Mt. Carrigain.
4. In Waten^ille and Albany. 5. Mt. Tom area. 6. In Bartlett, Jackson,
and Chatham. 7. Pilot Mountain range.

The Lafayette Range.

There is little to be added to the general statement, on page 220,
respecting the shape of this area. It is a narrow strip, about six miles
long, sometimes half a mile wide, from the north slope of Mt. Lafayette,
through Mt. Lincoln, the south peak, and Mt. Liberty to Mt. Flume.
Between the last two there is a marked curve to the east. The south end
of Mt. Flume is precipitous for several hundred feet.

The saddle between Lafayette and Lincoln has been cut down to the
Albany granite, leaving upon the former mountain a porphyritic cap
about one hundred and fifty feet thick; and a small hummock in the
depression has only fifteen feet of porphyry upon it. Beyond it to the
south is a dyke-like felsite mass, thirty feet wide. On Mt. Lincoln the
porphyry seems to slope south-easterly about ten degrees. From this
peak to the south end of the ridge, the summit is entirely composed of a
dark-colored porphyry. At the south end the divisional planes slope as
before ; and, about three hundred feet down, on the south-west side, we
found exposures of compact labradorite. These figures may express the
thickness of the dark porphyritic cap.

Direct observations between the south end of the Lafayette mountains
and Mt. Liberty are wanting. Liberty is capped by Albany granite ; but
we suppose its eastern slope is porphyry, which extends from the peak
south of Lincoln across to the pinnacle of Mt. Flume. It is at least six
hundred feet thick at the last named summit. (See vol. i, p. 42.) It is a
fact to be remembered, that where the uppermost part of the Albany

224 STRATIGRAPHICAL GEOLOGY,

granite comes in contact with the porphyry, it is full of distinct crystals
of orthoclase and quartz, just like the rock on Mt. Willard next the slate
breccia. The porphyry upon the top of Mt. Flume seems to slope north-
erly.

Between this ridge and the Franconia branch there is an area of twenty
or more square miles, — concerning which we have no information, — sup-
posed to be occupied mainly by the Albany granite.

Twin Mountain Area.

This comprises, first, the broad, elevated range between the most
northern of the Twin mountains, and well on to the south end of the
higher part of the mountain mass, about three miles in length ; second,
a long ridge on the west, between the Franconia and Redrock brooks ;
third, a north-easterly extension into Little River mountain (or perhaps
the latter may be isolated); and, lastly, a development on the east to in-
clude the divide between Little river and New Zealand pond.

From the side of the long, elUptic-shaped ridge on the west towards
Franconia Branch, we have specimens of Albany granite, but finer-grained
porphyritic varieties near the summit and the east side. The stream on
the east side, in descending from the west slope of South Twin, falls over
abundant ledges of red compact feldspar. Boulders from this locality are
strewn from here to Mr. Pollard's house in Lincoln, especially between
the mouths of the Franconia and Hancock branches. Their prominence
has suggested for this stream the name of Redrock brook.

There are several varieties of the porphyry on the summit of the South
Twin. The most common is fine grained, drab-colored, with reddish crys-
talline spots, all of it probably orthoclase, though at first sight suggestive
of labradorite. Our best specimen from this locality shows a few crystal-
line grains of clear quartz in the drab portion ; and there are bunches of
reddish-gray porphyry intermixed, holding the same red orthoclase bits
with the darker portions. In the descent towards Little river, on the
way to New Zealand pond, the rocks are varied with a sprinkling of
something like Chocorua granite. The felsite contains much quartz, and
a few small masses of a decomposing, dark greenish mineral. Somewhat
lower down Little river than its crossing, on the line of description, there
is a reddish granite. On climbing the ridge east of the stream, the slope

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 225

is found to be quite precipitous, allowing only a scrubby growth of trees.
From one fourth of a mile west of Little river to the slope towards New
Zealand pond, including the precipice and the divide, the rock is a fine-
grained porphyry carrying numerous distinct grains and crystals of quartz,
weathering whitish. On the east it is supposed to join the finer-grained
variety of Conway granite.

In ascending the most northern Little River mountain from the north,
after leaving gneiss, I found what is termed in my note-book a feldspathic
sandstone, much like the rock of Mt. Carrigain. At the very base of the
mountain a compact, dun-colored porphyry is present. The west side of
the mountain is like the ridge farther south, made of porphyry, with nu-
merous crystalline grains of quartz. It also has black patches of dark
porphyry in it. Our specimens from these more northern localities have
been unfortunately lost, through malevolence, — the only ones collected
by us from the whole mountain region not at present safely in the mu-
seum. It is likely that the porphyry is continuous from South Twin to
the northern Little River mountain.

There is also a small porphyritic area on the northern slope of the
water-shed between Little and Ammonoosuc rivers, about a mile south
of Twin Mountain station. Its place and dip of 65° S. 25° E. are indi-
cated upon Fig. II.

3. Mt. Carrigain Area.

The principal portions of Mts. Carrigain and Lowell are known to be
composed of dark-colored porphyries, with disseminated small crystalline
bunches of orthoclase, the general character corresponding with the rock
upon South Twin. It is likely that the rock of Mt. Anderson is the same.
Mt. Lowell is known in the older writings upon the White Mountains as
"Brick-house mountain," so called from the unusual abundance in it of
the red orthoclase crystals. It seems to stand east of the straight line
from Carrigain to Anderson, though not so represented upon any map
made before ours in the atlas. There is a slight resemblance between
the stratigraphical position of this porphyry and the slate on Mt. Willey,
Both rest upon the Conway granite, and they dip in opposite directions,
while between them is a much lower territory composed of the supposed
older rock. A believer in metamorphism might find resemblances be-
voL. II. 29

226 STRATIGRAPHICAL GEOLOGY.

tween the porphyry and slate sufficient to authorize the investigation of
the question of their identity. As one stands upon Mt. Willey, at the
upturned end of the slates (see p. 176), and looks southerly for its con-
tinuation, he would naturally fix upon Mt. Nancy as the place for it to
appear. Observation proves Mt. Nancy to be composed of the Conway
granite (p. 183), but the porphyry covers it to the south, with a slope
towards Carrigain; and this might possibly rej^resent the slate in an
altered condition. The statement made recently respecting the nearness
of the porphyry on Mt. Flume to the crystalline Albany granite, as com-
pared with Mt. Willard, is worthy of remembrance in this connection.

The essential part of our information concerning the Carrigain area of
porphyry is given in the description of Fig. 15, a section from Tin to
Hancock mountain (p. 147). The view of the Notch (vol. i, p. 596) ex-
hibits finely the south side of Mt. Lowell, with the precipice along the
middle, and three small slides. Mts. Anderson and Nancy appear imme-
diately behind. Between Carrigain notch and Carrigain is a conical peak
about six hundred feet below the former, and nearly of the same height
with Mt. Lowell. It is one of the porphyritic mountains, and is well
shown in the panoramic view from Mt. Tremont in the atlas. No. 58 of
Section VIII is a grayish porphyry, from an interesting dyke six feet
wide cutting porphyritic gneiss, at the mouth of Carrigain brook. (See
p. 103.)

4. Porphyry in Albany and Waterville.

The first and most important of these areas has been described upon
pages 148-150, in connection with a breccia of possible later origin.
Upon Little Deer brook there are outcrops of the red compact feldspar,
and a breccia chiefly composed of divers-colored porphyries, including
labradorite, quartz, and gneiss. This may possibly be the same with the
Mt. Mote and Mt. Pequawket breccias, which are largely composed of
andalusite slate, though with a feldspathic paste.

In Waterville there is a breccia of limited extent, adjacent to labrado-
rite rock upon the head waters of Sabba Day brook. And along Mad
river, in the vicinity of Greeley's hotel, and for two or three miles above,
there are numerous large boulders of red and purple compact and brec-
ciated feldspars, which I have thought may have been derived either from

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 22/

the cast spur of Mt. Osceola, or some of the mountams not far behind it
in Elkins's Grant. The locahty on Redrock brook seems too remote for
their source. Many of these boulders have been collected by Mr. Conna-
ble, who has spent eighteen summers at his cottage near Greeley's, and
they are tastefully arranged about his grounds in rustic seats, and dis-
posed in piles so as to intensify the colors by the water falling from an
artificial fountain.

5. Mt. Tom Area.

Not far from New Zealand river there are ledges of a feldspathic rock,
consisting of orthoclase and quartz with a fine-grained base, weathering
nearly white. Several shades of this rock occur all the way from the
western base to near the summit of Mt. Tom, — some of it resembling
sandstone, — having a northerly dip. There is more of it on the east side,
about as far down as Mt. Andalusite. It joins the andalusite and similar
slates upon the east, that which is nearest the supposed porphyry being
indurated. Scarcely any observations of the dips have been preserved ;
but the general impression is, that the feldspathic rocks overlie the slates.
In passing north-easterly from Mt. Tom the slates are succeeded directly
by the Albany granite, without the intervention of the porphyries.

I have found other ledges related to that on the west side, in ascend-
ing Mt. Field from the saddle between that and its eastern spur, and upon
the north shoulder of Mt. Field (p. 178). The Mt. Tom area is quite lim-
ited in its extent, and may be almost incorporated with the andalusite
slate group.

6. Bartlett, Jackson, and Chatham.

These are inconsiderable. The first is a small series of outcrops in
the valley of Rocky Branch, two miles above its mouth. It is grayish,
and was at first thought to be labradorite. The second is noticed upon
page 128, an area of two miles' extent upon the south-west side of Sable
mountain. If it occupies the limits suggested, as far south as Mountain
pond, the area would be four miles in diameter. Part of this rock is brec-
ciated, belonging to the later group. The porphyry in Chatham lies upon
a two-thousand feet mountain in the west part of the town, more than a
mile from the Jackson line. No facts have been preserved in regard to
the extent of this area, but it must be small.

228 STRATIGRAPHICAL GEOLOGY.

7. The Pilot Range.

This has been spoken of heretofore (p. 70, ct scq.). The principal area
occupies parts of Northumberland, Stark, Kilkenny, and Jefferson, twelve
miles in length, and is coterminous with remote mountains rarely visited,
save Mt. Starr King, near the Waumbek house in Jefferson. There are
two smaller areas, scarcely disconnected from the main mass, in Nor-
thumberland. On the south side of Mill mountain, in Stark, vertical
strata of arenaceous schist abut against the porphyry, with a strike nearly
at right angles to the course of the former. At first, I supposed this in-
dicated an elevation of the schists by the side of an older, harder mass.
A recent visit to outcrops east of A. Sawyer's in Northumberland would
seem to indicate the protrusion of the porphyry through fissures in the
schists, and hence the later origin of the former. If this be the correct
view, it follows that the whole Pilot Mountain area is an overflow of
igneous rock, resting upon the upturned edges of Huronian schists and
Atlantic gneisses. That is the view presented in the fuller account of
this region, already referred to.

SIENITE.

The principal sienitic area in the White Mountains has been spoken of
in connection with the labradorite rocks of Waterville (Fig. 19). It was
described in connection with those rocks for the sake of sketching its
relations to them. Moreover, the composition of that mineral aggregate
is peculiar, containing triclinic feldspars. The specimens from other lo-
calities differ in that respect, no feldspars having yet been detected in
them, except orthoclase. None of them, — neither that with the triclinic
feldspars nor the Chocorua varieties, — seem to agree exactly with those
in the other districts of the strata, unless it be a few about Lake Umba-
gog and Island Pond, Vt., in the Coos and Essex region.

We have noticed sienite at Jackson, Frankenstein cliff, Mt. Whiteface,
Mt. Passaconnaway, several places in Albany, and boulders, from some
unknown locality, near the Crawford house and Mt. Washington river,
besides that of Mt. Tripyramid and the Jackson tin mine.

In cHmbing Mt. Whiteface, the lower portion, so far as known, consists
of porphyritic gneiss, and the balance, perhaps a thousand feet, is made

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 229

1113 of sienite. The hornblende is in small crystals, disseminated sparsely
through crystalline orthoclase. It weathers readily, showing the colora-
tion of peroxyd of iron, and rarely manganese. A specimen from the
top of Mt. Passaconnaway proves to be of the same character, and one
from the northern ridge contains the mineral in profusion. These sum-
mits are three and a half miles apart. No one has gone from one to the
other, so that it is only by conjecture that we place the intermediate
space in the same group. As this variety seems to be intimately con-
nected with the Chocorua granite, it is likely that the region east of Mt.
Whiteface will be found partially composed of sienite, as appears upon
many of our specimens. Those which show hornblende came from the
summit of Chocorua, the ravine east of the main peak, and the end of
the south-east spur. The colored heliotype of Mt. Chocorua, described
upon page 232, will show the location of these parts of the mountain.
Other Albany localities are at Ellen's, Champney's, and Swift River falls.
Similar specimens came from Camel's Hump, south of Sawyer's river,
and from Silver Spring mountain. It is probable that hornblende will
be found occasionally disseminated through any mountain mass of the
Chocorua granite.

This is notably true of the ledge called Frankenstein cliff, through
which the railroad has cut. There seems to be a mass of this rock
slightly inclined north-easterly, starting from some unknown point on
the north flank of Mt. Nancy, and extending a little beyond the railroad.
Nothing needs to be added to the notice of it upon page 181.

Sable mountain in Jackson is composed of a sienite abounding in horn-
blende, much like that on the north side of Passaconnaway, and is con-
nected with porphyry and breccia. Three other localities are Chocorua
pond, a mile from Berry's saw-mill, and at Great Hill pond, all in Tam-
worth. Near the Crawford house a single large boulder of sienite, very
like that from the Chocorua group, has been found, in which Prof. Dana
discovered chrysolite. Its source is unknown. It is probable that the
same mineral will be found in some one or all of the localities that have
been mentioned, as the specimens from all of them are very much alike.
We searched the Frankenstein cut carefully for chrysolite, but found
none. Boulders of sienite containing chrysolite occur, also, upon Mt.
Washington river.

230 STRATIGRAPHICAL GEOLOGY.

CiiocoRUA Group.

The study of the sienites and other rocks from Albany shows that our
Chocorua group may be divided lithologically into three parts: — First,
the crystalline aggregation of coarse orthoclase crystals, both alone and
mixed with quartz, containing, also, mica in a few localities, so as to be
properly a granite. The feldspar is often greenish in color, and was
known by us, when exploring, as the "green granite," such as occurs
about a mile above the mouth of Hancock Branch (No. s%). The second
variety is a fine-grained, grayish-green, compact potash-feldspar. This is
common about Mt. Chocorua, particularly in the ravine on the east side
of the pinnacle. This variety merges into a porphyry, and both of them
pass into the Albany granite, such as constitutes Sawyer's Rock. None
of the kinds mentioned is so easily confounded with labradorite as this.
The third division is the sienite, whose particular distribution has just
been described. Whether these three kinds really belong to different
eruptive periods, or should be properly grouped as one, is a question for
the future never suggested before this moment of writing. No attempt
will be made to distinguish them upon the map.

CJiocoriia group in Vermont. Upon page 529, Volume I, it is stated
that there is a small area of Chocorua granite at Cuttingsville, upon the
Rutland & Burlington Railroad. The second and third of the above
named varieties are present there. Although the mineral is not labra-
dorite, as there stated, the argument for the age of the Green Mountain
rocks is valid, since there is a close agreement between the two gran-
ites and their associations. In the briefest terms possible, the argument
may be stated thus : Along the axis of the Green Mountains there occurs
a large overflow of granite, apparently identical with the Chocorua granite
of the White Mountains. In a limited region igneous rocks, having the
same mineral composition, must have been ejected from one vast caldron
of melted material, or at least at the same epoch. Therefore the granites
of Cuttingsville are of the same age with those of Mt. Chocorua. Fur-
thermore, the Chocorua rocks cut formations of Eozoic age; — therefore
the strata disturbed by the Cuttingsville outburst are of Eozoic date, or
older — they cannot be newer. And, as the rocks about Cuttingsville be-
long to the Green Mountain gneiss, that whole system must be as old

PX-ATA XL

lig. 25. Section hovoL Mi. Xafayette to Mt. Tom .

SCAL£ or F/GS 25 and Z.6; - %\ M s. to /kn I nch , Hom^oKy-ALLY ; 60O0. Ft. , VERTicALi

^< ChocoruaHid^e.

Eg26. Section from ]\[.E.coJ7ierof TamwoitJitoWMtesXed^e

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 23 1

as the Eozoic, — probably the same with the strata disturbed in the White
Mountains, — or the Montalban group. Hence it is not proper to say that
the Green Mountain rocks are of Sikirian age, as is claimed by some
authors.

I will add a few words descriptive of the Vermont locality, that those
who are interested may examine the region for themselves. Fig. 21
exhibits the relations of the granite there to the surrounding groups,
as portrayed upon a map of the Cuttingsville region, in the towns of
Shrewsbury and Wallingford. The Chocorua area is oval in shape, and
about a mile and a quarter long. Its western border is a rather coarse
sienite. The eastern part is a somewhat fine-grained variety of feldspar,
with a bare sprinkling of hornblende in it, but no quartz. The whole
constitutes a large hill, with a higher mountain of gneiss to the south, in-
the edge of Wallingford. Mill river flows by the eastern base of the hill,
parallel with the railroad. The dips of the gneiss, at a few points around
Cuttingsville, are given. On the east is a vein of magnetic iron pyrites,
which has been stripped for a quarter of a mile on the western slope of
the hill back of the depot. Its course is N. 65° E., and it seems to con-
stitute an anticlinal ridge. Limestone and hornblende schist accompany
the ore, all of these bands pointing directly for the granite hill, which has
interrupted their continuity. Where the railroad crosses Mill river, two
miles south from Cuttingsville, the dip is 35° N. 80° W.; on passing up
the hill west of this, hornblendic gneiss dips S. 5° W. Midway between
the railroad and J. Pelsue's house, at the end of a road, there is a large
exposure of the Potsdam quartzite, with some calcareous layers. North
of Pelsue's the gneiss dips 80° N. 2$° W., and resembles the Laurentian
gneiss of Whitehall, N. Y. The highest and principal part of this hill is
composed of similar material. The gneiss and hornblende adjacent to
the gneiss dips northerly, and farther north it dips westerly, so that its
strike is irregular in direction. The jointed planes of the sienite dip
northerly. Some of these seams are lined with manganese peroxyd.
The sienite hill may be three hundred and the other five hundred feet
above the valley of Mill river.

We conclude, from these statements, that this felsite mass is truly
eruptive ; that it issued from a rent transverse to the course of the strata,
but parallel with the main range of the Green Mountains. Its age must

232 STRATIGRAPHICAL GEOLOGY.

therefore be subsequent to that of the gneiss, and probably synchronous
with the period of upheaval of the range. As before remarked, its min-
eral character suggests the Chocorua granite. No similar rock has yet
been discovered from any part of this range. The rocks on the western
slope are largely covered by drift, so that areas much larger than this
near Cuttingsville might exist and not be known.

A heliotype of Mt. Chocorua, taken from the hill about a mile east of
Tamworth Iron Works, has been colored to show the situation of the
several rocks in the field of view. The details in regard to the rocks
have been given upon pages 153 and 154. The pinnacle and south-east
spur are composed of Chocorua granite; the eastern ridge, of Albany
granite; the lower part of the right flank, of Conway granite. The fore-
ground belongs to the Atlantic series of gneisses. Certain parts of the
mountain area are left uncolored, as we have not the necessary data to
represent them.

ANDALUSITE SLATES.

Clay slates, or argillo-mica schists carrying andalusite occasionally,
and clayey sandstones constitute the bulk of this formation, attaining,
perhaps, a thickness of 1200 feet, supposing the strata to be folded once.
The two principal areas of these slates have been described upon pages
116 and 175, the first at its crossing by the Mt, Washington carriage-
road, and the second under the name of the Mt. Willey range. The third
area consists of two small patches on the north and south sides of Mt,
Pequawket. It is probable that these three areas were once joined to-
gether, the first two effecting a junction near the third, the line of strike
having a V shape. A glance at their present wide separation from each
other, as portrayed upon the map, will illustrate powerfully the magnitude
of the di.slocations and extent of denudation to which the rocks of New
Hampshire have been subjected.

The mineral character of the variety of this rock carrying andalusite
is shown by the analysis of G. W. Hawes, herewith presented. Allusion
has been made to it upon page 179.

New Haven, Conn., Aug. 24, 1875,
Prof. C. H. Hitchcock :

Dear Sir — Inclosed you will find the analysis of the slate, which you requested.

Calculations from the analysis, confirmed by microscopic observations upon a thin

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, 233

section, show that the rock is composed of orthoclase feldspar, a foliated mineral re-
sembling chloritoid, titanic iron, and a few flakes of mica. The titanic iron is dissemi-
nated all through the rock, in very minute particles, and the analysis shows that it
constitutes four per cent, of the whole. The feldspar is very poorly crystallized ; and
the pei'centage of alkali shows that nearly half the rock is common feldspar. Deduct-
ing the titanic iron and orthoclase, we have a percentage which nearly represents the
mineral chloritoid, and the variation from it is accounted for by the presence of the
hydrated mica, which can easily be seen. The low percentage of silica accounts for
the great difference from the granites on each side, which. Prof. Dana has told me,
are so placed ; and the analysis shows that this was a much more muddy layer, which
did not possess the necessary ingredients to be changed into granite by metamorphic
action.

Yours faithfully, GEORGE W. HAWES.

Analysis of the Andalusitic Slate, from the Portland 6^ Ogdensburg Railroad bridge
over IVilley brook.

Silica, 46.01

Alumina, 30.56

Ferric oxyd, ........... 1.44

Ferrous oxyd, 6.85

Manganous oxyd, .10

Magnesia, ........... 1.42

Potash, . . • 6.66

Soda, 1. 12

Titanic acid, 1.93

Water, 4.13

100.22

There are rocks on the east slope of Mt. Madison containing immense

stauroHtes (described on page 1 14), which may possibly be the northward

continuation of those occurring along the Mt, Washington carriage-road,

amply illustrated upon Plate VII and page 116, There are also the Pine

Hill rocks (p, 113), which are suggestive of the slate series. On the

south it crops out between the Pinkham notch and Crystal falls. To

the south in Jackson and west of the Ellis river is a large district that

none of us have traversed, where this rock may be found, as along New

and Cutler's rivers. A specimen collected for us by Prof. Vose, four miles

above Jackson falls, is placed with these slates in our museum, and may

possibly represent such an extension. The few ledges cropping out

along Ellis river are referred to the Montalban series.

An examination of the dips along the Mt, Washington carriage-road
VOL. II. 30

234

icAi. (;koi.O(;y.

siip:t;csts readily tlio stiiulurc of lliis formation. Tt is a crushed, nearly
inverted synclinal axis, overlyinj; the Monlalban system, perhaps uncon-
formably. Both systems are characterized by the i)resence of crystals of
andahisile. 'I'hese are usually uuich lar<^er in the newer than amonj;
the older strata, save where they have been altered into Damourite, as at
Willis's Seat. The Monlalban andalusite commonly occurs like chewed
l)ieces of toothpicks, si-allered indiscriminately throui;!! the ledges.

The slates about Mt. ]'e(|uawket occur in two limited isolated localities,
one on tlie south side, and the other opposite, on the east branch of the
Saco, about a mile and a half above its mouth. The two are nearly in
their pi-oix-r place for a continuation of the ran.i;e southerly from the val-
ley of ICllis river. Tt may be that these two areas are continuous beneath
the granitic and brccciatcd cap of the mountain, although the strike of
the southern mass does not point towards the northern. The disturb-
ances which accompanied the formation of the breccia may have de-
ranged the course of the slate, so that its original direction is lost, or
there might be a bend in its course similar to that below Mt. Willard.
These localities are over two miles apart. The northern one is the larg-
est, extending easterly from the river. No andalusite has been noted in
these slate ledges; but the boulders derived from them in Conway dis-
play the silicate in jirofusion, so that the affinities of the formation arc
unmistakalile. It occurs to us now, that the "dark siliceous schists" of
Jackson, ilescril)cd upon i)age 130, may i)erhai)s be referred to this series.
If so, there would be opportunity afforded for showing further the truth
or error of the supposed connection between the different areas of anda-
lusite slate.

Further reflection upon the character of these schists from Jackson
suggests their similarity to a supposed jxvrt of the Huron ian system
already described as occurring along the lli)])er Anunonoosuc region,
and also to be sjioken of hereafter in Rockingham county. The small
outlier cast of Berlin falls is of the same sort. At various times the pos-
sibility of an intimate connection between the Andalusite slates and the
Iluronian schists has been thought of. This suggestion will receive
speedy attention from us. By reference to the catalogue and the map
illustrating the distribution of specimens, it will appear that the quartz-
itcs and ferruginous schists, — Nos. 84, 129-132, 135-137, 142, 144, 146,

GEOLOGY O'.' THE WHITE MOUNTAIN DISTRICT. 235

147, 149-152, 160, 289-293, 297-301, — belong to this group, and that
they extend in a narrow belt north-easterly from Iron mountain, in Bart-
Ictt, through Jackson, essentially parallel with the range in Coos county.
There seems to be an anticlinal axis in it, also; but this probably does
not express the proper structure of the whole mass. The strata are gen-
erally monoclinal, constituting an overturn synclinal, like the rocks on
the Mt. Washington carriage-road.

PEQUAWKET .SERIES.

The last of the groups of rock among the White Mountains to be con-
sidered are the Mt. Pcquawket or Mt. Mote breccias and porphyries.
The andalusite slates are the most recent of the stratified formations
known to exist in this district; and consequently a breccia formed by
its dismemberment, as well as the accompanying feldspathic ejection,
must have been of later origin. The Pequawket and Mote areas are
alike in composition, and may have been parts of the same original mass,
cut in two subsequently by the Saco river. In the west parts of Albany
and Watcrville are other breccias, perhaps to be referred to the same
eruptive period. If so, the porphyry period is probably coeval with it.
There is also a mass of somewhat similar material constituting the more
northern Twin mountain, while upon Mts. Willard and Tom the breccia
is identical with that of Pequawket. For convenience, we will describe
in turn the breccia and the rocks associated with it in each area, consid-
ered geographically.

Mt. Pequawket.

The state of our information respecting the structure of this mountain
has been given partially in Volume I, page 43. Very similar statements
concerning this mountain were made by Dr. Jackson, in his report, which
I will quote for the sake of perfecting the record of the history of opin-
ions about our geology.

On ascending the mountain on its south-eastern side, we came first to a coarse
variety of granite, consisting of feldspar and quartz, without any mica, which is over-
laid by a breccia of granite and argillaceous nlate, above which rest the regular strata
of argillaceous slate, which run N. 75° E., S. 75° W., and dip to the N. N. W. 30°, the
strata dipping towards the mountain. This slate is compact, and is much broken and
twisted, so that it would not answer for covering roofs. Occasionally a few good slabs

236 STRATIGRAPHICAL GEOLOGY.

may be obtained, which might answer for tombstones or for platforms, but no attempt
has yet been made to quarry them. Higher up the mountain we discovered a very
singular breccia, made up of the large broken fragments of the argillaceous slate
rocks, mixed confusedly with the granite which closely invests them. This breccia
was evidently formed by the eruption of granite through a thick bed of argillaceous
slate rocks, the strata having been broken into fragments of a rhomboidal form, and
into pieces which vary from a few inches to a yard or more square. The fragments lay
in every imaginable position, just as if they were swept up by a thick, pasty mass of
semi-fluid granite, which indurated around them by cooling. Some of the masses were
rendered scoriaceous, and resemble vesicular trap rock, but generally they do not ap-
pear to have been much altered by heat. The granite contains no mica, but is com-
posed principally of feldspar, with a little quartz. There are no rounded or waterworn
pebbles in the breccia ; hence it cannot be considered as a conglomerate of aqueous
deposition. This locality proves most incontestibly * * * ^^^t the eruption of
the granite rock of this region took place immediately after the deposition of the roof-
ing slate. * * * On reaching the summit, the rocks were found to consist of a
very hard breccia, composed of the same kind of granite before described, containing
small fragments of slate rarely more than an inch in diameter.*

The accompanying heliotype of Mt. Pequawket will show better than
words the relations of the several rocks to each other. The view was
taken from a small hill east of the McMillan house, and south of the
Portland & Ogdensburg Railroad depot in North Conway. The lowest
rock receiving a color is the Conway granite, which also occupies all the
foreground not otherwise designated. About three hundred feet of the
lower part of the mountain are entirely composed of this granite. It has
been found at about the same elevation above the sea on three sides of
the mountain, — hence the conclusion naturally suggested is, that its sur-
face is a nearly horizontal floor. The next strip is likewise nearly hori-
zontal, thickening at the western side towards Bartlett. This is the
Albany granite, perhaps fifty feet thick, on Section VIII, No. 6. This
has been seen at several localities on the south side; and, on the path
usually taken in the ascent of the mountain, it is thought to be from one
hundred and fifty to two hundred feet thick, and still thicker on the slope
towards Saco river in Bartlett. The position of the slate is indicated by
the small patch of color overlying the narrow belt of Albany granite.
The upper part of the mountain consists of a breccia, in which the fcld-
spathic paste may vary from three to ninety-nine per cent, of the mass,

* Final Report, p. 8i.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 23/

and it is all represented by a single color. Further exploration would
enable us to subdivide this upper portion. The lower eminence to the
left of Pequawkct is now called Bartlett mountain.

In the ascent up the bridle-path west of the slate ledge, one remarks
the presence of trap-like fragments in the Albany granite; and, before
reaching the breccia, there are a few feet thickness of a fine-grained
quartz-porphyry, in which both the quartz and orthoclase occur as dis-
tinct and perfect crystals. The first part of the breccia, — perhaps one
hundred feet, — is almost entirely composed of slate fragments, insomuch
that a search with a lens is needful to discover any cementing feldspar or
quartz. In the midst of the breccia, also, there is either a ledge of slate
or a fragment thirty feet thick, dipping east, in the same direction with
solid masses of the same material higher up the mountain in the path.
The path lies to the west of the chief mass of the slate, on the south side
of the mountain. As the strata dip east along the path, there is evi-
dently a synclinal axis in the mass of slate. As we ascend the mountain,
the proportion of slate fragments in the breccia diminishes. The other
rocks present are white quartz, probably from veins in the slate, and
several varieties of porphyry. As the cementing material begins to pre-
dominate, it slightly resembles the Albany granite, with the porphyritic
aspect indicated by crystals of feldspar somewhat less distinct. Occa-
sionally the resemblance will be so great as to excite the query whether
the Albany and Pequawket granites are not identical.

The following is a list of the specimens obtained in a section (VITI)
over Pequawket and Bartlett mountains, which may illustrate better than
a protracted description the succession of lithological variety. The first
one named comes from the east side, it being the first ledge succeeding
the Montalban system in Chatham.

6. Albany granite — orthoclase crystals, one fourth to one half inch in length ; a
small amount of amorphous quartz, and a dark pepper-and-salt base. From the east
base of Pequawket, one mile east of the west line of Chatham.

7. Porphyry — dark slate-colored base ; crystals of quartz and orthoclase dissemi-
nated, and scattered fragments of uncommonly flinty compact feldspar, from one twen-
tieth to one half an inch in diameter. From near No. 6.

8. Porphyry — gray base or paste ; crystals of quartz and orthoclase present ; black
fragments very conspicuous, on account of the contrast in color between them and the
base, usually one fourth of an inch in size, and much like a granular slate. From the

238 STRATIGRAPHICAL GEOLOGY.

summit. Other specimens from the smnmit contain a smaller number of fragments,
conspicuously large crystals of orthoclase, and have a reddish color.

9. Porphyry — very much like the preceding — with black slaty fragments an inch long.
Near the summit.

ID. Slate breccia from near the slate. Pieces, one fourth to an inch and a half long,
of veritable slate, and one white quartz pebble. From eight to ten per cent, of feld-
spathic cement.

II. Fragment of black compact slate ; 12 — of gray quartz ; 13 — white quartz; 14 —
reddish compact micaceous feldspar, — all components of the breccia. Other specimens
represent genuine porphyries.

15, 16. Slate. Nos. 9-16 are from the south slope of the mountain.

17. Breccia, composed chiefly of dark compact feldspar fragments, with about fifteen
per cent, of paste. From top of Bartlett mountain. Nos. 18-26 are from the west
slope of this spur.

18. Porphyry, with reddish base ; pieces of dark compact feldspar and quartz crystals
in the base.

19. Gray compact feldspar or porphyry holding numerous minute crystals of quartz.

20. Porphyry, with reddish-gray, somewhat crystalline base ; quartz crystals abun-
dant ; contains an inch fragment of trap-like porphyry, itself carrying feldspar crystals.

21. Both drab and light gray base, each color carrying small crystals of quartz and
feldspar, and bits of dark porphyry.

22. Like 19. 23. Like 21.

24. Compact drab-colored feldspar, very like the fragments seen all through the
mountain imbedded in the porphyry.

25. Porphyry, with dun-colored base, minute crystals of quartz, and white, irregular
blotches of feldspar from an eighth to one quarter of an inch in length.

26. Porphyry, with an abundance of dark brown paste, carrying numerous crystals
of quartz and minute crystals of orthoclase, and one or two small pieces of compact
feldspar.

27. Albany granite, like No. 6. This ledge is about a mile east of the road from
North Conway to Bartlett.

It is noticeable that the distinctively slate breccia is confined to the
proximity of the slate ledges on the two sides of the mountain, while the
balance of the dark pieces consists of compact feldspars, a mass of which
occurs at No. 24, on the west side. Explorations might discern other
areas of it on other surfaces of the mountain. The length of this por-
phyritic area is about three miles cast and west — somewhat less north
and south.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 239

]\It. INIOTE.

There is an extensive area of brecciated porphyries, similar to those
just described upon the two mountains west of North Conway, between
the Saco and Swift rivers, known as the Mote mountains. On examin-
ing the specimens, in connection with the full description given of this
area upon pages 14S-150, it appears that there is a considerable porphyry
present distinct from the breccia. It occurs all the way from Bartlett to
the summit of the ridge following up Stony brook, above Diana's Bath
and Farnum's, in all cases beneath the breccia. The more central part,
or the north peak, contains the greatest amount of andalusite slate frag-
ments, the pieces averaging coarser than on Mt. Pequawket. At the
southern extremity, as at the western, in the other case, there is an
abundance of porphyritic cement without slate.

The identity of the Mt. Mote with the Mt, Pequawket breccia seems
well established. But farther west in Bartlett, Albany, Waterville, etc.,
there are breccias associated with porphyry composed of different classes
of fragments, still with a similar cement. As we found a variation upon
Mt. Pequawket, occasioned apparently by proximity to particular ledges,
it would seem probable that all the breccias with feldspathic paste must
be of the same age, and formed subsequently both to the eruption of the
original porphyry and the deposition of the slates. The area in the west
part of Albany contains fragments of mica schist, labradorite, porphyry,
and quartz, and, when near the outcrop, bits of bright red compact feld-
spar. These ledges are connected directly with the breccias of Mote
mountain, and have been noticed upon page 148. Another case has
been mentioned as occurring about the head waters of Sabba Day brook
in Waterville. Wherever boulders of red porphyry occur, there are many
of a brecciated character, showing a probability of their formation at the
same time with those in Albany, Bartlett, and Chatham. This was re-
marked in particular at Waterville.

Tw^iN Mountain.

After ascending Twin mountain, in 1871, which was before the exami-
nation of the Bartlett and Chatham area, I referred the rock of the north
peak to the Albany granite ; but later investigations prove that it belongs

240 STRATIGRAPHICAL GEOLOGY.

to the same class of porphyritic breccia with that upon Mts. Mote and
Pequawket. From the crossing of the axis of the ridge by Little river,
to a short distance south of the north Twin mountain, the granite is
specked by small black pieces of mica or hornblende schist, and quartz
crystals are abundantly disseminated through the feldspathic paste; and
jointed planes dip about ten degrees northerly. The north-west spur, or
the mountain mass west of the small stream flowing northerly from the
summit, is of the Albany variety. The south Twin mountain has been
mentioned as being composed of porphyry. The length of this mass
holding black fragments of schist is a little over two miles.

Mts. Willard and Tom.

On page 177 allusion is made to the presence of a narrow band of
breccia on the south face of Mt, Willard, and on page 165 to the same
upon Mt. Tom. On page 178 it is remarked that masses of the same
slate breccia occur just behind the north spur of Mt. Field. All these
cases I conceive to be examples of the same breccia occurring so abun-
dantly upon Mts. Pequawket and Mote, though none of the masses found
are known certainly to exceed twenty feet in thickness. They all occur,
also, on the eastern border of the slate adjacent to the Albany granite.
They are of too limited extent to be represented upon the general geo-
logical map.

A large portion of the Mt. Willard breccia differs from that on Pe-
quawket in being much more compact, in containing a variety of pebbles,
and in having a different cementing material. The rock superficially
resembles trap with a glazed coating or tarnish in the joints, and fre-
quently no fragments are displayed, except after weathering. The mate-
rials are principally a compact slate, a looser schist, with pretty black
mica (phlogopitc?) sprinkled through it, gneiss, granite from veins in the
Montalban series, and numerous very small bits of glassy quartz not crys-
talline. The paste is dark gray, considerably lighter than the schistose
fragments, and is notable for the very black scales of mica (muscovitei*)
scattered through it. Some irregular patches of white feldspar may be
connected with the paste rather than with the fragments. This breccia,
though quite near the Franconia group topographically, is very distinct
from it in the character of the paste and the included fragments. The

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 24 1

porj^hyry containing perfectly formed crystals of quartz and orthoclasc,
mentioned upon Mt. Pequawket, is much more finely developed upon Mt,
Willard ; and the band has been mentioned heretofore (p. 177) as belong-
ing to the Albany granite.

[Note to Page 100. Since the printing of the statement concerning the section
from Mt. Lafayette to Bald hill, additional observations at the Wing road have con-
firmed our supposition that the porphyritic gneiss underlies the Bethlehem group. The
particular details of structure appear in the illustration, PI. VI, Fig. 7.]

[Note to Page 119. A reexamination of the ledges enables us to modify certain
statements upon page 119. Above the fifth mile-board, for a quarter of a mile, the dips
are mostly low and undulating, like those at the end of the fifth mile. The high dips
mentioned here have an existence, they being the occasional plunging downwards of
one side of the curves. I could not satisfy myself that the dip of 5o°-6o° N. 73° W.,
at No. 44, pertained to a ledge. And it is erroneous to state that the ledge in the sharp
angle of the road overlooking the Great Gulf is one hundred and fifty feet long. The
sedgy plat near No. 47 is now known as the "cow pasture." Instead of saying "ten
rods north of mile-post No. 7," it would be more correct to put it "ten rods before
coming to mile-post No. 7." There is a ledge at the first great easterly bend, corre-
sponding essentially with No. 48. Below the barn the first ledge dips 50° S. 82° W.
I have not preserved the observation respecting a dip at No. 50.

We remark that the steep side of all the curves is on the east, or down the mountain.
One of the zigzags at the fifth mile-board is now called "Willis's Seat." Since the
drawing of the plan, the sixth and seventh mile-boards have been moved down the
mountain, so that, as measured on the plan, the distance between five and six is less
than a mile. I have retained the old positions for them. No. VI is now placed more
than half-way towards No. 45 of the space between 6 of the plan and 45 ; and, conse-
quently, VII has been shifted to stand at No. 48. In the neighborhood of Willis's
Seat the large andalusite crystals have been altered into quartz and Damourite.

For comparison, I have drawn upon the section through Mt. Washington (PI. VII)
the dips along a nearly parallel line, down Tuckerman's ravine to the Pinkham Notch
road. The anticlinal and synclinal axes correspond well with each other. The lower
end of the section at the Notch represents the eastern boundary of the Montalban .sys-
tem, which appears on the carriage-road at the Half-way house ; though I have some-
times thought the rocks about Willis's Seat belonged to the newer group. The greatest
amount of crushing is manifested in the area of the slates between Nos. 12 and 36.
The structure of the latter seems to be a complicated and crushed inverted synclinal.]

[Note to Page 182. There are a few points concerning the representation of the
boulder showing curvatures in the strata requiring mention. It is figured in Plate X,
Figs. 22, 23, and 24. Fig. 22 is the one spoken of as on the left, and Fig. 23 as the
one on the right. Fig. 24 is an additional view of what may be termed the bottom,

242 STRATIGRAPHICAL GEOLOGY.

nearly opposite Fig. 22. The stone is rather triangular in shape. The figures refer-
ring to the lines of curvature will be found placed to agree with the description.
Owing to a slight change in the position of the stone, the top view is more extensive
than as originally described. What is called the shorter fault is the one nearest the
letter A, the changed position permitting its representation larger than at first seen.
We can also see the smaller fault of the side view at its beginning on the top. The
letters A, B, and C indicate where the edges of the adjacent sketches join each other.
Every side is rejjresented. The two faults do not seem to join on the lower side, but
to approach near each other and then diverge again. The black crystals seen all
through the layers are of hornblende.]

[Description of Heliotypes. Since the printing of the account of the Franconia
breccia along the Portland & Ogdensburg Railroad and the Flume upon Mt. Willard, I
have had heliotypes taken to illustrate them, and placed opposite this page. The ce-
ment of the fragments is the "Breccia granite" described upon page 169; and the
ledge photographed is a rock cutting where the railroad makes a sharp turn westerly,
nearly at the northern limit of the Conway granite. The large fragments so well
shown are the Montalban schists, fractured by lateral pressure, and cemented together
without removal by transportation. A reexamination of the breccia of the same appar-
ent age at Franconia indicates the cement there to be very much like this in the Notch.

The larger flume described on page 172 is represented on the other side of the helio-
type. The view was taken from the inside, near the top, looking out towards Mt.
Webster. It is impossible to obtain any photograph that will adequately represent the
whole of the chasm. The name of the discoverer was first applied to this interesting
cleft in the ledge by a large party of tourists from Massachusetts, shortly after the
description of its geological character on the aforementioned page had been written.

Another double heliotype illustrates Mt. Crawford and the Lake of the Clouds (p.
182). The first represents the appearance of Mt. Crawford from the hill back of Dr.
Bemis''s house. Most of the precipitous slope visible is composed of Conway granite.
Glen Crawford appears at the extreme right. The rock at the Lake of the Clouds is
the common andalusite mica schist of the main White Mountain range. The ice still
partly remained when the negative was taken, in the month of May, on account of its
great altitude — 5000 feet.

Several of the heliotypes have been colored to show the distribution of the forma-
tions. It is not possible at this time to say what these colors are ; but it is hoped that,
by comparing the heliotypes with their descriptions, the significations of the several
tints will be perfectly understood. One is the view of Mt. Willard, noticed upon page
177. The other view upon the jMate represents a mass of breccia granite, situated in
the midst of Montalban schists, in the Silver Cascade. The colors of the Mt. Pequaw-
ket heliotype may be explained by studying page 236. The Mt. Chocorua heliotype is
spoken of upon page 232. The double plate showing the Eagle Cliffs of Franconia
breccia, by the side of Pemigewasset granite, is noticed upon page 139.]

PLATE XII

WHITE MT. DISTRICT TWjjEt^V i;

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 243

Catalogue of the White Mountain Collection.

The area included in this catalogue corresponds essentially with that
of the White Mountain district, save that the specimens from the north
of Moose river have been incorporated into the Coos County collection,
given on pages 81-86. The locations of the specimens will be found
accurately portrayed upon Plate XII. Owing to discoveries and addi-
tions made after the writing out of the catalogue, the order is not strictly
a numerical one, but it can be easily comprehended by those who choose
to compare the positions of the specimens on the plate with the colors
on the final map, or the descriptions of the stratigraphical and lithologi-
cal parts of the report, or to study the rocks themselves in the museum
at Culver Hall. The arrangement by age is not quite perfect, but will
not produce embarrassment. Where several specimens came from very
nearly the same locality, all their numbers are not drawn upon the map.
Unimportant numbers are often omitted, as in the case of many traps
and small beds. In the museum there is a manuscript catalogue specify-
ing the lithological character and localities with all needful particularity.
The same is true of the Coos and Essex District collection.

PORPHYRITIC GNEISS. Waterville.

Franco7iia. 29, 30, 31, 35, 495, 496, 640, 642, 652,
1-6, 8, 12, 15, 17, 23, Porphyritic gneiss. Porphyritic gneiss.

7, 14, Trap. 33, Gneiss.

10, 13, Coarse granite veins. 34, Trap.

11, Mica and feldspar, mica predominat- 641, Banded quartz vein.

ing. Sandwich.

2,2,2,1 Fine-grained gneiss. 36-39, Porph}Titic gneiss.
Lincoln, Conway.

9, 19, 20, 21, Porphyritic gneiss. 40, Porphyritic gneiss.
16, Hornblende schist. BETHLEHEM GNEISS.

Landaff. Franconia.

18, Porphyritic gneiss. 41, 42, 48, 49, Granitic gneiss.

Thornton. 43' 4^) Chlorite schist layers.

22, Fine-grained gneiss. 47> Chlorite schist, with magnetite.
24, 26, 32, Porphyritic gneiss. Lincoln.

27, Coarse granite vein. 50, 52, Chloritic gneiss.

244

STRATIGRAPHICAL GEOLOGY.

51, Gneiss, with black mica and much or-
thoclase.

Pcmigcivassct.

53, Gneiss.

Carroll.

54, 54 a, Granitic gneiss.
176, 177, Porphyritic gneiss.
408, 409, Chloritic gneiss.

Jefferson.
407, Chloritic gneiss.

FRANCONIA BRECCIA.
Francojiia.
55' 56, ^Z-' Gneiss, with black mica.

61, Porphyritic vein — quartz and ortho-

clase in crystals.

62, Porphyry, with hornblendic cement.

64, Compact granite — the cement of 65.

65, Breccia.

From head of Eagle Cliff to Echo Lake,
66-74.

66, Dark gneiss — top of Eagle ClifF— hold-

ing 78a.

67, Porphyritic gneiss — a fragment in brec-

cia.

68, Mica nodule in 66.

69, Almost Concord granite, with larger

crystals of mica and feldspar.

70, Granite — top of middle peak.

71, Coarse dark gneiss — top of third peak.

72, Like 69 — top of third peak.

73, Pebble from eruptive granite vein near

Echo lake.

74, Granite, with black mica — below por-

phyritic gneiss.

75, Porphyry, with much dark micaceous

cement.

Lincohi.

57, 58, Breccia of fragments of porphyritic
and Lake gneisses, cemented by fine-
grained granite. Basin.

59, 60, Dark porphyry, with mica. Basin.

76, Granitic, with dark mica.
T], Granitic cement of breccia between
Mts. Profile and Kinsman.

78, Dark gneiss.

78 a. Coarse granite vein from No. 66.

Mt. Willard.
78 b, Coarse breccia.
78 c, Gneiss from 78 b.

LAKE GNEISS.

Fraficonla.
25, Gneiss. East of Lake of Clouds.
321, Gneiss. N. W. flank Mt. Lafayette.

Carroll.
3i5) 316, 317, Gneiss.

Bethlehem.
318, 319, 320, Coarse granite.

Sandwich.
369, Micaceous gneiss.

Waterville.
28, Gneiss. Summit Sandwich Dome.

MONTALBAN SERIES.
East Part of White Mountain Dis-
trict.
SJielburne.

79, Concord granite.

80, 80 a, Fine-grained dark gneiss.

BeaiCs Purchase.

81, Chloritic gneiss.

82, 87, 92, Gneiss, with blotchy mica.

88, Gneiss.

89, Mica schist, with blotchy mica.

90, Vein of quartz and hornblende.

91, Dark Concord granite.

379, Concord granite.

380, 381, Granite veins.

Jackson.
83a, 126-128, 143, Concord granite.
85,86, 117, 123, 156, Gneiss, with blotchy
mica.

83, 140, Gneiss.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT.

245

120, 122, 124, 125, 14S, Mica schist, with

blotchy mica.
116, Andakisite gneiss.

118, Porphyry.

119, 134, 138, Trap.

121, 133, 139, 141, 154,391, Granitic veins.
84, 129, 130, 135, 136, 137, 150-152, 160,

Quartzite.

131, 144, 146, 147, 149, Fine-grained mica

schist.

132, 142, Ferruginous schist.
145, Andalusite mica schist.
153, 158, 159, Limestone.

155, 157, Dark Concord granite.
391, Granite, with tourmaline and garnet.
Chatham.
93, 94, Coarse Concord granite.

95, 97, 102, 103, 385, Concord granite.
99, Very fine-grained granite.

96, 98, 107, IC9, no, 112, Gneiss, with

blotches of mica.
100, loi, 104, Gneiss.

105, 108, Trap.

106, III, 385, Granite vein.

Maine.

113, Gneiss. Lowell.

114, Granite vein. Lowell.

115, Granite vein. Stoneham.

Main Range of White Mountains.
Gorhain.
i6r, Andalusite mica schist.
162, 163, Mica schist.
164, 165, 166, Concord granite.
Rafidolph.

167, Coarse mica schist.

168, Ferruginous vein.

169, 171, Hornblende schist.

170, Coarse granite vein.
172, Micaceous gneiss.

Jefferson and Carroll.
174, Trap.

175, Mica schist.

IVatinihelc.

178, 189, 190, 194-196, 199, 210, 219, 222,
225, 231, 232, 234-236, 240, 242, 244,
246-249, 252, 253, 255, 256, 265, 268,
Gneiss, with blotches of mica.

179, 186, 204, 205, 213, 229, 272, 279, 285,
Mica schist.

180, 191, 192, 193, 197, 267, 381, 406, Con-
cord granite.

181, Muscovite.

182, 183, 187, 280, Staurolite mica schist.

184, 206, 207, 233, Andalusite gneiss.

185, Gneiss, with garnets.
188, White quartz vein.

200, 201, 203, 208, 211, 224, 228, 230, 254,
269, Mica schist, with blotches of
mica.

202, 216, 245, Hornblendic beds.

212, 217, 218, 281a, Dark, fine, compact
gneiss.

198, 215, 227, 241, 380, 381, 270b, 270 c,
404, 415, 281 b, 398, Granite veins.

209, 220, 258-262, 273, 275, 302, White
trap.

214, 233, 239, 257, 263, 264, 277, 303, 312,
Trap.

226, 237, 238, 271, 278, 283, 284, 304, Fer-
ruginous schists.

266, Gneiss, with much silica.

270, Chloritic gneiss.

270 a, Hard gneiss.

274, 276, Fine-grained gneiss.
Jackson and Bartlett.

286, Hematite.

287, Porphyry.

288, Tourmaline granite.
289-291, 297-301, Quartzite.

290 a, Chlorite, with calcite carrying cop-
per.
290b, Ferruginous siliceous limestone.

246

STRATIGRAPHICAL GEOLOGY,

292, 293, Ferruginous schist.

294, Gray gneiss.

295, Ferruginous gneiss.

296, Coarse mica schist.

West and South-west from the Saco

River.

Near the Saco.

250, 250 b, 250 d, Concord granite.

251, 251 b, 251 c, 417, Hard gneiss.
251 a, Gneiss, with much mica.
250 a, 251 f, 251 g, Trap.

250 e, Feldspathic vein.

251 d, 251 e, Breccia granite.

305, 307, Gneiss, with mica patches.

306, Curved strata. Part of boulder fig-
ured upon Plate X.

308, Granite dyke.

309, Mica schist.

310, 313, Gneiss.

311, Chlori tic granite.

419, Compact feldspar, with grains of

quartz.
419 a, Gneiss, with much feldspar.

Fraiiconia.
322, 323, 326, 329, 331, 332, Gneiss.

324, Hornblende schist.

325, Gneiss, with irregular patches of mica.

327, Trap.

328, Granular quartz friable from decom-
position.

330, Soft clayey mica schist.
Landaff.

334, Mica schist.

Lincoln.

335. 336, Gneiss.

337, Dark fine-grained gneiss.

338, Coarse granite vein.

Woodstock.

339, 340, 341 » 345. 346, 348 a, 350, Gneiss.

342, Gneiss, with fine black mica.

343, Concord granite.

344, Trap.

347, 351, Granite veins.

348, 349, Gneiss, with much black mica.

Thornton.

352-354, 356, 378, Gneiss.

355, Granite bed.

2,S7, Feldspathic mica schist.

358, Andalusite gneiss.

359, Andalusite gneiss, with garnets.

Pemigcwasset.

360, Gneiss, with pyrites.

Albatiy.

361, 362, Fine-grained granite.
Z^l)': 539> Gneiss, with black mica.

364, Granite vein.

Tatuworth.

365, Gneiss, with much mica.

366, Dark Concord granite.

367, Granitic gneiss.

Sandwich.

368, Concord granite.

369, Lake gneiss.

370, Junction of gneiss and sienite.

371, Gneiss, with much mica.

372, White quartz.

373, Gneiss.

374, Fine-grained dark gneiss.

375, Gneiss, with decomposing pyrites.

376, Gneiss, with irregular mica.

377, Mica schist.

PEMIGEWASSET SERIES.

Conway Gkanite.

Chatham, Jackson, and Bartlett.

382, 383, 386, 387, 389, 390, 392-395, 397,

Normal Conway granite.
384, Finer reddish granite.
388, Red granite.
396, Manganesian granite.
432, Trap.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT.

247

435, 435 a, 436, 437, 439, Finer variety re-
sembling the normal, save in coarse-
ness of texture.

438, White porphyritic feldspar, with a lit-
tle mica.

U'ain/ibck.

399, 431, Granite.

400, 401, Dark brown granite — mangane-
sian.

402, Tourmaline granite, the quartz cryp-
to-crystalline.

403, Normal Conway granite.

428, Reddish porphyritic feldspar, with lit-

tle mica.

429, 430, Compact feldspar.
442, 443, 447> D'11-k granite.
444, 453, Mostly red feldspar.
446,

457, Fine-grained feldspar, with coarse
crystals, and quartz crypto-crystal-
line.

Pemigeivasset — west part.

460, 461, 461 a, 462, 465, 466, 468-471,
635, Finer-grained variety.

463, 464, 478-481, 485-490, Normal Con-
way granite.

472, 475, 476, 477, Granite.

474, Very fine-grained granite.

483, 484, Trap.

Watcrvillc.

491, Granite, feldspar predominating, both
compact and in coarse crystals.

492-494, 501-504, 506, 629, 630, Normal
variety.

499, 500, 631, Finer-grained variety.

497, 498, Fine-grained quartz, very feld-
spathic, with crypto-crystalline quartz,
approaching porphyry.

505, Trap.

510, Normal granite, with greenish feld-
spar and tourmaline.

Albany.
467, 506, 511, 512, 520, 522, 523, 527, 529,
53 1 > 532, 534> 537, 54^, 644, Normal
variety.

507, 517, 519, 521, 524, 526, 540, 541,
Finer-grained variety.

508, 514, 518, Trap.

509, Finer porphyritic granite.

513, 516, 530, 536, Fine-grained, compact

granite.
528, Porphyry vein.
538, Compact feldspar — nearly.
Coniuay.

543, 545, Normal variety.

544, Fine-grained vein.

Albany Granite.

C/iat/ia?n, Jackson, Bartldt, and Conivay.

545 a, 547, 552, 553, 556, 561-563, Porphy-
ritic granite. 549-551 have quartz in
form of crystals.

546, 566, 558, 560, 564, the same, without
quartz.

554, Junction of granite and banded mica
schist.

555' 557' Porphyritic granite — two feld-
spars and little quartz.

559, Crystalline and compact feldspar.

565, Granite.

IVanmbek.
567, 568, 569, 571, Granite,
Peniigewasset.

566, 572, 575, 578, 579, 583 a, 589, 603,
607, 608, 628, Feldspar, porphyritic,
and mica.

573. 574' 577. 58°, 581. 587' 59i. 59^, 596,
599, 602, 609, 610, 625, 627, 634, 636,
637, Quartz and feldspar, porphyritic.

582, Large reddish crystals of feldspar in
dark dioritic base.

583, Porphyritic granite, with dark base.

248

STRATIGRAPHICAL GEOLOGY.

583 b, Well-formed quartz and feldspar
crystals.

585, 590, Granitic — mostly feldspar.

588, Granite.

S93» 594' Porphyritic diorite.

598, 604, Quartz crystals in compact feld-
spar.

626, Compact sienite.

Franconia and Lincoln.

611-614, 618, 619, 620, 621, Mostly crys-
talline feldspar.

615-617, Fine-grained porphyritic granite.

622, 623, Porphyry.

624, Porphyritic granite.

IVaterville and Thornton.

632, Trap.

^1>2>^ 634, 637, 638, Mostly crystalline feld-
spar.

636, 639a, 643, Porphyritic granite.

639, Granite.

Albany and Contuay.

645-650, 658, 663, Mostly crystalline feld-
spar.

651, 652, 653, 654-657, 662, 664, 665, Por-
phyritic granite.

659-661, Mostly compact feldspar.
Chocorua Group.
North and east of Saco River.

433. 435. 548, 681, 683, 684, Fine-grained
sienite.

434, Sienite and trap.

520, Feldspar, with a little hornblende.
695, Sienite, passing into Albany granite.

South and west of Saco River.
5'S> 533» Sienite, with two feldsjDars.
535, 667, 672-676, 678, 679, 685-690, 693,

696, 697, Fine-grained sienite.
666, 687, Coarse sienite.
663, 669, 671, 680, Crystalline feldspar,

with quartz.
670, 691, Compact feldspar.

()^^, 682, Granite.

677 a. Trap.

692, Coarse mica bunches in 690.

694, Sienite, with chrysolite.

LABRADOR SYSTEM.
Mt. \]'as]iington River.

698, 703, 704, Ossipyte.

699, Crystalline labradorite, with biotite.
700-702, Labradorite, hornblende, and bi-
otite.

705, Compact labradorite.

706, Ossipyte, with hornblende.

Lincoln.

707, 708, Compact labradorite. Analysis,
page 220.

709, Compact feldspar, perhaps orthoclase.

IVaterville.

710, Ossipyte, with hornblende.

711, Crystalline labradorite.

712, Dark ossipyte. Analysis, vol. i, p. 39.

713, Labradorite masses in finer-grained
matrix.

714, 715, Dykes of trap.

716, 717, Compact labradorite.

718, Fine-grained porphyry.

719, Labradorite and hornblende.

720, 721, 724, 730, Andesite, orthoclase,
and hornblende in small crystals.

722, Fine-grained feldspar and mica.

723, 738, Labradorite, biotite, and horn-
blende.

725, Orthoclase, from very coarse granite
vein.

727, Coarsely crystalline labradorite.

728, 736, Coarsely crystalline labradorite,
biotite, titanic iron, epidote. Analy-
sis, vol. i, p. 40.

726, 729, 732, Fine-grained sienitic dykes
cutting 728, etc.

IZ"^-: I'h'h^ 739' Fine-grained orthoclase and
hornblende.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT.

249

734' 735' IVl'' Coarse ossip3te, with biotite.

Jackson Tin Mine Adit.
741, 742, Coarsely crystalline labradorite
and hornblende, with few crystals of
orthoclase.
ANDALUSITE SCHIST GROUP.
743. 744' 750. 752, 754. 757. Clay slates.
745-748, 75 1 , 753, 756, Micaceous quartzite.
749. 755' 761, Andalusite schists.
758, 759, Mica schist.
760, Banded vein, chiefly calcite in 759.
Moosilauke.

762, Andakisite mica schist.

763, 764, Micaceous quartzite.

765, Quartz vein in 763.
765 a, Granite.

PORPHYRY.
yackson, Baj'tlett, and Chatham.

766, 769, 770, Greenish compact feldspar.
"](>•], Porphyritic breccia.

768, Breccia of porphyry, mica schist, and

quartzite.
771, Porphyry.

Pevtigeivasset.
482, 772, 778, 779, Porpliyry.
ni, 781-785. 787. 791-793. Porphyries,

with more or less quartz.

774, Sandstone, with 772.

775, 780, 794, 796, 797, Greenish compact
feldspar.

776, 'J']'], 786, Porphyries, with reddish
crystalline spots.

778, Amygdaloidal porphyry.
779, Porphyry, passing into Albany granite.
790, Light drab compact porphyry.
795, Gray porphyry, with bits of dark

schist.
798, 79S a, Red porphyry.

MT. PEQUAWKET BRECCIA.
Pemigewasset.
597, 605, 606, Porphyritic breccia.
VOL. II. 32

799, 804, Porphyry, with crystals of quartz

and orthoclase and fragments of schist

and porphyry.
Soo, Soi, Hornblendic porphyry.
802, 803, Porphyry.

Mt. IVillard.
805, Porphyry, with crystals of quartz and

orthoclase.
576, S06-809, Breccias, with fragments of

slate, porphyry, gneiss, mica schist,

quartz, and feldspar.

Mt. Pequawket.

811, 817, Slate breccia.

812, 813, 814, Breccia, with porphyritic
base holding crystals of quartz and
feldspar.

815, Porphyry, with very little slate.

816, Porphyry, with large piece dark fel-
site.

818, Fragment of quartz porphyry — 819 of

trap from 817.

IVaterville.
820-823, Breccia, with minutely crystalline

feldspathic and micaceous paste.
Bartlett and Albany.
824, Porphyritic dyke.
825-827, Quartz porphyries.
828, 829, 831-834, Porphyritic breccia.
830, 835, Micaceous quartz porphyry.

836, Gneiss, (?) with 835.

837, Porphyritic breccia — red and dark por-
phyry fragments.

838, Red porphyry.

839, Dark compact porphyry, with diorite
fragment and pyrites.

840-842, Porphyritic breccia — fragments
of reddish, gray, dun, and black por-
phyries, labradorite, and gneiss. Ce-
ment of light gray porphyry holding
amorphous quartz and crystals of feld-
spar.

250 STRATIGRAPHICAL GEOLOGY.

Jackson and Bartlett. 856, 857, Dun-colored porphyry, with nu-

843, Breccia, with granitic paste. merous crystals of quartz and feldspar.

844, Black compact brecciated feldspar. 858, Purple porphyry.

845, Brecciated trap — granitic paste. 859, Dark quartz porphyry, with crystals of

846, Dun-colored quartz porphyry. quartz and feldspar.

Mote Moitntain. 860, 861, Slate breccia.

847, Porphyritic breccia — bits mica schist S62, 863, Breccia — greenish porphyry frag-
— compact paste holding c^uartz crys- ments— dark base holding crystals of
tals. quartz and red feldspar.

848, Quartz poryhyry. 864, Black porphyry.

849, Light-gray compact feldspar. 865, Purplish porphyry, with crystals of

850, 851, Slate-colored porphyritic breccia. white feldspar and quartz.

852, Quartz porphyry paste, with quartz 866, Compact greenish feldspar, and piece
fragments. of dark micaceous porphyry.

853, 854, Slate breccia. 867, 868, Compact greenish porphyry, with
855, Compact feldspar holding crystals of crystals of red feldspar and quartz.

quartz, and feldspar and slate frag-
ments.

The following numbers of the catalogue were accidentally overlooked : 44, 45, Fine-
grained and granitic gneisses of Bethlehem group, from Franconia ; of the Montalban
group, 173, Coarse mica schist, Chatham; 221, Granitic rock, from half a mile south
of Glen Ellis falls; 243, Ferruginous gneiss, a little more than three miles from Craw-
ford house towards Mt. Clinton; 281, 282, Mica schists, from Mt. Hope. No. 314 is
the same with 251. On page 245, line 14, second column, 233 should be 223; and,
eleven lines below, 415 should be 405. Insert 409a after 409, page 244, line 9. Of
the Conway granite there should be added for Pemigewasset, the north and east parts,
Nos. 410-416, 422, 422a, 422b, 423, 423a, 423b, 423d, 424, 424a, 426, 440, 445, 449,
451, 455, 459, for the normal variety; 418, 418a, Compact feldspar and andalusite
schist fragments in this rock up Cascade brook; 420, 423c, 425, 427, 446, 451 a, 452,
454, 456, 458, Fine-grained variety; 4236, 446a, Trap; 447 approaches Chocorua
granite. Of Albany granite, 595, from Pemigewasset. The numbers 442-457, under
Waumbek, came from Pemigewasset.

Note. Plate XII, the map illustrating the position of the specimens belonging to
the White Mountain collection, shows, in addition, the location of the numbers pertain-
ing to Sections IX, VIII, and a little of VII west of Sandwich. These are drawn of a
larger size, I have, also, for convenience, given the numbers, in a few cases, of speci-
mens collected outside of the district. They will be referred to hereafter in the de-
scription of the adjoining territory, save what belong to the Coiis and Essex district,
which have been already catalogued. In Whitefield, Nos. 694-719 have been mostly
enumerated upon page 86, but are here classified more intelligently. No. 694, with the
majority of the others, may be seen to be situated to the south and east of the upper

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT, 2$ I

boundaries of the Bethlehem group. 695 and 719 belong to the Lake gneiss. Then
there are two small areas of the Coos mica schist. AH the numbers bordering the
Ammonoosuc river in West Bethlehem and Littleton, save those belonging to Section
IX, will be found enumerated in the catalogue of the Ammonoosuc region, likewise
everything in Lisbon. The smaller numbers in Landaff, Benton, Warren, Ellsworth,
parts of Sandwich, Tamworth, Madison, Eaton, and Conway, are mostly from the gen-
eral catalogue of lithological specimens, numbered in continuation of that ending on
page 86. The areas of the several formations are inclosed by heavy lines, the naiTow
ones representing the 500-feet contours. The names of the various locations, grants,
mountains, ponds, rivers, etc., may be learned by comparison with other maps in the
Atlas. The dips of the strata are given so far as we have reliable information concern-
ing them.

Final Statement of Opinions.

This chapter will not be complete without a rhwn^ of the present
opinions held by the writer respecting the age and elevation of the
White Mountains. I have quoted everything of importance written by
others respecting them, from the convulsion theory of Dr. Dwight to the
proposal of the existence of an undescribed formation, by Dr. Hunt. I
cannot further advert to the gradual progress of our views, than to refer
to the chapters upon the history of the present survey, and a few im-
provements upon them suggested while this volume has been passing
through the press. A few statements in the early part of this chapter
have been modified by later explorations, and the changes are mentioned
farther along. I propose now to state briefly the general conclusions
obtained respecting the age and equivalency of the formations, and the
principal physical changes effected in the condition of the district.

The order of the systems seems to be the following: First, the Lau-
rentian, represented by the porphyritic gneiss and the Bethlehem group.
Second, the Atlantic, consisting of the Lake or Berlin and Montalban
gneisses, and the Franconia breccia. Third, the Labrador, Fourth, the
Huronian, Fifth, the Merrimack schists. Sixth, the Andalusite schist
group. Seventh, eruptions of porphyry. Eighth, eruptions of the Con-
way, Albany, and Chocorua granites and sienites. Ninth, the formation
of the Mt, Pequawket or Mt, Mote porphyritic breccia. This order is
somewhat different from that stated at the beginning of the chapter,

1. Lanrentian. Dr, Hunt has expressed to me his opinion that both
the porphyritic and the Bethlehem gneisses agree essentially in litho-
logical character with the schists he has observed in typical Laurentian

252 STRATIGRAFIIICAL GEOLOGY,

regions; and Prof. Dana (p. 109) has discovered similar resemblances in
the upper member of the second group. Our observations lead to the
behef that they are the oldest formations in this district, and suggest
that they may belong to the upper division of the Laurentian system as
it is developed in Canada and New York. We have two leading and
divergent ranges of the porphyritic group, each suggestive of an anticli-
nal structure (PI. VI, Fig. 7 and Fig. 12), the first underlying the Beth-
lehem gneiss. The Bethlehem group is noted for a nearly east and west
strike, is marked by an anticlinal structure when flanked by the Lake
gneiss (Fig. 11), and has porphyritic beds in its lower member. The
Bethlehem synclinal, if correctly interpreted, is inverted. We may note
the improvement of Plate VI, Fig. 7, above the statements upon page 1 10,
and the development of the eastern range in Waterville, coming up again
also in Albany, near the western line. More irregularities appear in its
course in Sandwich.

2. Atlantic. The lowest division of this newly-described system is
best developed in the more northern part of the White Mountain dis-
trict, the rocks having been partially described in Chapter II. They are
the "Older rocks" (p. 6j) and the "Granite and granitoid gneiss (p. 'j-'^.
The Berlin gneiss seems to constitute an anticlinal axis, with both Huro-
nian and Montalban schists overlying each flank (Figs. 4, 5, and 6). This
band possesses a very inferior development in this district south of Jef-
ferson, because the principal mass lies to the west of it. The limited
range from near Mt. Hale across to Franconia appears to overlie both
the porphyritic gneiss and Franconia breccia, and to correspond to the
Whitefield, Jefferson, and Littleton outcrops on the other flank of the
older groups. Its continuity across Franconia is interrupted by a south-
erly extension of the Bethlehem, as if it had been worn away down to a
lower formation. In Sandwich we perceive the commencement of the
large Winnipiseogee Lake development of this series, as well as the
smaller area embracing the Dome.

The Montalban portion of the Atlantic system has a large representa-
tion in this district. It constitutes the foundation of the principal higher
range of mountains from Success across the Androscoggin river to Mt.
Webster, and is then supposed to continue beneath the granites and por-
phyries to connect with the same series in Thornton and Waterville,

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 253

and by a fold with similar exposures in Tamworth and Madison. The
presence of newer formations indicates two synclinals, though inverted,
along the east flank of Washington and in Jackson. We find a marked
anticlinal in the valley of Mt. Washington river, and between Jackson
and Fryeburg, Me. The Thornton section (Fig. 12, p. 135) indicates a de-
gree of unconformability between the Laurentian and Atlantic systems.

StrucUire of Mt. WasJiiiigton. The section across the highest moun-
tain of this range may be taken to represent the structure of the range;
and the facts along this route have been given with much particularity.
(See p. 116, ct seq., and PI. VII.) The predominating dip is somewhat
north of west. What may perhaps be the main anticlinal axis is that
extending from the "cow pasture" to the upper part of Tuckerman's ra-
vine, while a second runs parallel to it three fourths of a mile farther east.
The common condition of the folds seems to us to indicate an inver-
sion, the easterly-dipping strata being crowded beneath those inclined in
the opposite direction. There will be a low, undulating easterly dip for
several rods ; then the strata suddenly change and stand upon their
edges, or else dip at a very high angle into the mountain. This sudden
change in the dip is supposed to be caused by the enormous pressure
crowding the eastern flank beneath the western. Moreover, so far as
investigated, there are no easterly dips on the west side. I think the
westerly dips in the deep Ellis and Peabody valleys may be the contin-
uation downwards of strata dipping easterly on the surface of the moun-
tain.

The view had been proposed by Prof. Vose, that the westerly-dipping
schists of the Washington range represented the western part of an anti-
clinal, the Carter mountains being probably the commencement of the
eastern dip (p. 198). The measurement of Section IX across Bean's Pur-
chase does not confirm this suggestion. The westerly dip prevails across
to the line, while there are minor variations, as a limited synclinal about
the upper part of Mt. Carter. Passing south-easterly more nearly across
the strike, the north-westerly dip continues to the state line at Fryeburg,
and perhaps farther, save a limited area in Jackson of newer rocks, which
may indicate a synclinal fold. After reaching Maine, the dip changes to
easterly and south-easterly all the way to Sebago lake, as shown upon
Plate III. On the Grand Trunk Railway the easterly dips are reached

254 STRATIGRAPHICAL GEOLOGY.

in Gilead. We have, therefore, a problem of this nature: Given, a for-
mation about forty-five miles wide. One third of the width on the west-
ern side possesses a north-westerly dip, with at least two newer bands
disposed within it. The other two-thirds width on the eastern side pos-
ses a south-easterly dip, with supposed newer bands of unknown number.
The structure of the whole mass is certainly anticlinal in aspect ; but the
western part has not more than half the thickness of the eastern, and
there are evidences of synclinals in it. The proper explanation of these
phenomena would seem to be that inversion is the normal condition of
the whole area. A somewhat local pressure might produce a uniformly
inverted dip in the western area. Independently of this, other peculiarly
acting forces might invert the eastern area with its subordinate bands in
the other direction. I think it will be shown farther on, that this main
anticlinal line is the place for the subterranean development of the Lake
gneiss, or one of the other lower groups. This fact would indicate a ris-
ing of the underlying terrane, but not sufficient, perhaps, to bring it to
the surface in the elevatory period, while in the formative epoch the
older series existed as a shoal or island, upon both sides of which the
same kind of Montalban schists was being deposited. To the south-west,
the lower formation now crops out at the surface ; but from Tamworth,
across to Oxford county, Me., the upper schists covered it, perhaps be-
cause of its submergence. Granting this explanation, it is easy to under-
stand how, in the later elevatory periods, each side of an anticlinal line
should be inverted separately, and the forces exerted so that the inclina-
tion shall be in opposite directions. A similar example is afforded by the
Connecticut Valley and New Jersey Triassic areas. The former basin
invariably dips easterly, the latter westerly, while there is a broad area
of older rocks between. The question has been raised whether each of
these Triassic areas has not been inverted. If it is possible that each
one could be inverted, so that the apparent dip shall be in opposite direc-
tions, much more truthfully can the same supposition apply to the two
flanks of the Montalban anticlinal, where inversions are the rule rather
than the exception.

By measuring the course of the waved strata upon the cast side of Mt.
Washington, we can determine the direction in which the force of eleva-
tion has been exerted. The course of the range is about N. N. E.; and

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 255

the direction, N. 23° W., S. 23° E., is the one that seems the most com-
mon in the measurement of dips. In the case of inversion, the force is
commonly conceived of as acting in a direction opposite to that of the
dip ; hence the course upon Mt. Washington would be S. 23"^ E. Along
the Atlantic border the direction is usually stated as proceeding invaria-
bly from the ocean, or at right angles to that indicated among the moun-
tains. The pressure of the older gneiss area of Randolph and Berlin
towards the ocean would therefore seem to have been greater than that
of the submerged formation in Carroll county, from Madison to Frye-
burg, towards the north-west.

Much might be said respecting the date of this elevation that would
be profitless, since the facts indicating the epoch of disturbance are
meagre. After the conversion of the Montalban strata into schists,
whether by metamorphism or original chemical deposition, we have evi-
dence of powerful disturbances among them ; — in other words, this was
the time of the formation of the Franconia breccia, when ledges of moun-
tain size were first shivered into fragments, and then cemented by erup-
tions of fine-grained granite. As this same series occurs at Franconia
and the Notch, fourteen miles apart, and possibly in Essex county, Vt.,
thirty-five miles away from Franconia, the action must have been wide-
spread, and therefore powerful. That this period of eruption is distinct
from that of the Pemigewasset granites, is shown by several considera-
tions: I. The Uthological character is different. The breccia cement is
the fine-grained rock described above (p. 169) as the "Breccia granite,"
bearing some resemblance to the so-called Concord granite, and very
little to any of the Pemigewasset series. 2. The latter are of later origin
than the breccia, because none of it has been found either in the frag-
ments or cement of the formation. 3. The Pemigewasset granites are
usually developed in massive overflows, while the Franconia cement is
more limited in amount. 4. The coarser granites are found constituting
the cement of clay and andalusite slates, the fragments of which have
not undergone metamorphism. There is, therefore, a Franconia and a
Pequawket breccia, formed at widely different periods, the materials of
which are very different from each other. It should be remarked, how-
ever, that the numerous large veins of Breccia and other varieties of
granite usually occur quite near the later series, as upon Mts. Webster,

256 STRATIGRAPHICAL GEOLOGY.

Willard, and Crawford ; and the veins do not extend far away from the
ragged edge. 5. The relations of the Labrador system to the Montalban
are of much importance in this connection. Fig. 20, PI. VIII, shows the
Montalban elevated at angles of sixty degrees, overlaid by labradorite
rocks dipping ten or twelve degrees upon the average. Similar sections
could be drawn for the Waterville area, save that the lower formation is
older than Montalban. These sections appear to indicate that the first
elevation was very extensive, and that it was mainly effected before the
deposition of the Labrador system. Granting that the Labrador system
is well established as a geological horizon, it follows that the whole At-
lantic system precedes it in time, and is to be regarded as a subdivision
of the Laurentian group rather than of anything later.

These considerations lend probability to the suggestion, that not long
after the close of the Montalban period there were disturbances resulting
in the ejection of melted rock, and the beginning of the elevation of the
Mt. Washington range. At this epoch it is probable that the principal
part of the elevation was effected, the range having attained a great alti-
tude. It is likely that there has never been a more important epoch of
elevation in the physical history of New England.

The next period of elevation, of which evidence is afforded by the
structure of the range, occurred after the deposition of the andalusite
schists. It may be premised that there were ridges upon both sides of
the later schists, so as to constitute the hydrographic basin in which they
were deposited. Two epochs of this elevation can be insisted upon, the
first to bring the secondary series into the same position with the pri-
mary; and, lastly, an interesting upheaval that seems to have determined
the great altitude of Washington. On page 1 1 8 it is stated that the sec-
ond fold has its axis almost at right angles with the first. The axes of
the smaller curves along the road near the third mile-post run N. 30° W.
Others higher up, that are more constant, dip N. 2,^° E., twenty-seven
degrees more southerly than those first mentioned. It is not common,
or at least it has not been often stated in geological treatises, that the
same ledge will show evidence of forces acting nearly at right angles to
each other in successive periods. It is the minor curves that run N. 30°
W. The result of this reduplication has been the intensification of the
altitude, just as a change of wind produces higher waves in the ocean.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 257

What should have caused the force to spend itself in this northerly or
southerly direction is not so easily apprehended. On the north of the
mountains, the Bethlehem and Lake groups run nearly east and west.
Is it possible that this area served as a buttress against which the south-
easterly masses of rock (in the Lake district) were crowded, and, being
immovable, reacted upon the pliable upper schists, bending them to con-
form to its own shape ? Perhaps an inspection of the maps may suggest
other and better explanations. The age of this last elevation will be
referred to again, as it belongs to the Paleozoic period.

Another limited area of Montalban rocks in Pemigewasset has been
discovered since w^-iting pages 1 31-137, and it is shown upon the map
(PI. XII). It is situated along the west side of Hancock Branch, between
Black mountain and the Greeley Pond notch. Nothing is known of the
position of the strata there, nor are the proper limits of its distribution
ascertained. It is mentioned upon page 109, in connection with the
Bethlehem group.

Franconia Breccia. Much of what needs to be said about this forma-
tion has just been stated. In brief, there are two areas of it in this dis-
trict,— in Franconia and Lincoln, where it is overlaid and divided into
two parts by the Conway granite, — and in the White Mountain notch.
The ledges consist of angular pieces of porphyritic gneiss and Mont-
alban schists, cemented by a fine-grained granite. In the Notch the
fragments do not seem to have been transported at all. The ledges
have been shivered, and the pieces cemented again so near each other
that one can see the same line of fracture in those that are adjacent.
The breccia was thought at first to be a local formation (p. 141). Now,
in consequence of the discovery of similar rocks in the Notch, and the
ejection at the same time of granite veins all along the sides of Mts.
Webster and Crawford, the disturbance seems to have extended over
more than a local district. Specimens from other parts of the state are
like this granitic cement, and future research may suggest the occur-
rence of the breccia in the other topographical districts.

3. Labrador System. The modifications of the first five groups are

of less importance than those Vv^hich follow. The evidence is plain that

the Labrador system does not include, besides the triclinic feldspars, the

porphyries and all the Pemigewasset granites. Hence the statements

VOL. XL 33

258 STRATIGRAPHICAL GEOLOGY.

respecting the nature of the events transpiring in the Labrador period, —
given in the chapter upon the physical history of the strata, — pertain to
a later epoch. The Pemigewasset granites have no connection with the
labradorites. The theory of a connection between them was based partly
upon the nature of the rock underlying the Waterville labradorite. Our
first account of it was correct, in substance, that it was gneiss. Subse-
quently it was thought to consist of the "trachytic" or Albany granite;
and the erroneous estimate of the Pemigewasset series based upon it.
Our further study of the specimens proved the rock to be a part of the
porphyritic gneiss area (p. 156); and the reexamination of the ledges con-
firmed the return to nearly the original supposition. Then a reconsidera-
tion of the mutual relations of the porj^hyries and labradorites elsewhere
has not yet given any decided proof of their intimate association, nor of
their superposition upon the Albany granite. We are therefore led to be-
lieve that the labradorites alone represent the Labrador system, and, as
thus limited, it has been described (pp. 209-221). There are seven small
areas of it, cut by a sort of "sienite" containing triclinic feldspars, and
therefore supposed to close the period. The reduction of the Labrador
White Mountain areas will render it necessary to abbreviate also those
described upon page 11, Chapter I, The reality of the system is not af-
fected by the removal from it of these various porphyries and granites.
Their elimination makes the correspondence perfect between the New
Hampshire and Canadian areas, thus establishing more firmly the exist-
ence of the series.

Some difference of opinion may exist among geologists as to the rela-
tions between the Montalban and Labrador systems. We have not found
reason to change the conclusions derived from the section along the Mt.
Washington river (PI. VIII, Fig. 20). The labradorite rocks, with a very
moderate dip, rest unconformably upon the greatly upturned edges of the
Montalban schists, as if there had been large upheavals at the close of
the Montalban period, and comparatively little disturbance since. I un-
derstand that Dr. Eugene A. Smith, state geologist of Alabama, finds a
similar state of things in his field of labor — labradorites resting upon
Montalban schists. The facts as interpreted arc of great consequence,
since they fix the geological horizon of the whole Atlantic system, while
considerations of a stratigraphical character confirm this impression.

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 259

4. HiLvonian. As at present defined, the Iluronian barely touches the
edge of the White Mountains in Lancaster and Northumberland. On the
east side of the Stark porjDhyry mountains exists a large development of
hydro-mica, argillo-micaceous, and hornblende schists, with quartzites,
which seems better allied to the Huronian than to any other group.
The area on the map (PI. V) is made to begin in Stark and Milan, ex-
tend north-easterly through Dummer to Errol, and then diminish to an
extremely narrow band passing north-westerly to join a range of upper
Huronian in Dixville and the divisions of Carlisle's Grant. The rocks
agree with much of the area mapped as Huronian in Columbia and Strat-
ford.

Closely connected with this area in character are the Jackson quartz-
ites, the rather nondescript schists west and north of Umbagog lake, the
Merrimack group of the southern part of the state, and, more remotely,
the andalusite slate group of the White Mountains and elsewhere. The
first will probably be colored as Huronian upon the map ; the others will
be distinguished from it for the present.

5. Merrimack Schists. This formation will be described in succeeding
chapters, as it is best developed in the south part of the state. It is
probably the equivalent of the eastern band of Huronian in Stark and
Dummer. Further study of it may afford us better views of its proper
character.

G. Andalusite Slate Group. In Massachusetts this group is found as-
sociated with the preceding in such a way as to suggest its later age. In
Michigan a similar rock is given as the uppermost member of the Huro-
nian. The mineral chloritoid found in the specimen from Willey brook
by Mr. Hawes (p. 233) is suggestive of the Huronian. The range run-
ning through Mts. Moosilauke and Carr preserves a closer resemblance
to the Montalban andalusite or fibrolite schists than those in the White
Mountains. In our preliminary reports this has been ranked with the
Coos group along Connecticut river, which it resembles chiefly through
the similarity of the minerals andalusite and staurolite. The associated
rocks are different in the two areas. I desire to call the attention of
future explorers to the possibility of finding more of this formation upon
the east spur of Mt. Madison and Pine mountain.

A possible clue to the age of this formation is afforded by its htho-

260 STRATIGRAPHICAL GEOLOGY.

logical resemblance to the lower Skiddaw slate of the Cumbrian moun-
tains in England. These are Cambro-Silurian.

Prof. Sedgwick divides the Cumbrian rocks of northern England into
three parts: (i) Skiddaw slate or Lower Cumbrian; (2) chloritic slate
and porphyry, or Middle Cumbrian ; (3) Coniston group or Upper Cum-
brian. These arc regarded as the equivalents of the Cambrian, from the
Longmynd to the Bala group, or, in this country, from the Potsdam slates
to the Trenton.

Concerning the Skiddaw slate, wc have the following language from
the introduction to a systematic description of the British Paleozoic fos-
sils in the geological museum of the University of Cambridge (p. Ixxxiii,
1855):

Immediately over the central granite of the Skiddaw forest we have a very co.npli-
cated metamorphic group, superior, perhaps, in importance to any other metamorphic
group in South Britain. It has mineral veins which, though apparently of a much
older epoch, present very interesting analogies to the mineral veins of Cornwall. This
subgroup passes almost insensibly into the ordinary lower Skiddaw slate, through the
intervention of a chiastolite rock and a porphyritic chiastolite slate.

7. PorpJiyry. This rock often passes insensibly into the feldspathic
part of the Chocorua group. Dykes of it cut the porphyritic gneiss, all
the divisions of the Atlantic group, and the Huronian. In one of our
annual reports it was ranked with the upper Huronian, because it resem-
bled closely the stratified porphyries referred to this series in Massachu-
setts, New Brunswick, Ontario, etc. It seems best now to call it eruptive,
since so many dykes of it are found in the White Mountain district. Its
period of eruption is thought to have preceded that of the Pemigewasset
granites, because fragments of the porphyry are contained in the Albany
granite, on Mts. Pequawket and P'lume, and in the Conway on Cascade
brook.

8. Pemigcivasset Granites. These have cut the andalusite slates, and
are therefore of later origin, whether that be Eozoic or Paleozoic. The
theory of an overflow may not be tenable, — certainly it is not applicable
to certain portions of the field occupied by the granites.

Two additional sections crossing these granites have been added upon
Plate XI, in order to illustrate their surface outcrops and supposed inte-
rior connections. Fig. 25 shows the rocks between Mt. Lafayette and

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 26 1

Mt. Tom. On the west side of Lafayette there is an outcrop of porphy-
ritic gneiss at Eagle lake [Clouds], with Franconia breccia lower down
the mountain, having a supposed inverted position beneath the former.
Above both is a narrow band of Lake gneiss, succeeded by Albany gran-
ite, the summit being capped by porphyry. The granite is supposed to
occupy all the surface as far as to Redrock brook, when it is succeeded
by red compact feldspar. The porphyry upon Little river, east of the
Twin range, has a different texture and color from that on Redrock
brook, but is supposed to have been erupted essentially at the same time
with it, as well as with that upon Mts. Lafayette and Tom. The Pequawket
breccia occupies the summit of the Twin range, being an ejection of later
date than the porphyry. The Conway granite has not been certainly
detected on the west side of the Lafayette range, on the section line,
though it occurs abundantly a short distance south of it. Judging from
its usual topographical position, it extends beneath the Albany granite,
from just above the Lake gneiss, to the east slope of Little River moun-
tain and New Zealand river. For similar reasons, the two outcrops of
Albany granite upon Mt. Tom are supposed to unite beneath the slates ;
and the Conway is beneath the Albany series. No attempt is made to
show the internal relations of these several igneous rocks to each other,
as decisive evidence on this subject yet remains to be gathered.

Upon Fig. 26 will be found a section from the Montalban series near
Chocorua pond, Tamworth, to White's ledge, north of the Saco river, in
Bartlett. In Tamworth the Concord granite has planes dipping five or
six degrees northerly; but the true position of the strata has not been
determined. Probably it dips at an angle of seventy degrees in a north-
westerly direction. The Conway granite has a fine development in the
neighborhood of Knowles's pond, but is less conspicuous directly upon
the section line back of Piper's house (p. 153), where it is situated higher
than the Montalban ledges. Between this outcrop and the first appear-
ance of the Chocorua granite, the ledges are concealed. This is the
place of the Albany granite, which covers a very large area to the north-
east of this spur. The Chocorua granite occupies all the area from the
end of the spur to Ellen's falls, near Swift river. The Albany granite
then makes its appearance, occupying the whole of the lower part of the
valley. It is not capped by the Chocorua granite upon the north side,

262 STRATIGRAPHICAL GEOLOGY.

but by red compact feldspar and the Pequawket breccia, which occupies
a greater space here than in its other area east of the Saco. No ledges
of slate have yet been found upon Mt, Mote, while the breccia is full of
its fragments, inclined a few degrees northerly. On the north side a
porphyry makes its appearance underneath the breccia, followed by the
Albany, and then the Conway granite. The supposed continuation of
the latter sheet from Tamworth to Bartlett, beneath the other eruptive
rocks, is forcibly suggested by the position of the outcrops upon the
opposite sides of these mountains.

The general arrangement of these granites agrees with what has been
stated heretofore, in respect to their topography. As a rule, the Conway
granite is overlaid by the Albany; while the Chocorua series and the
porphyries are never seen below either of those first named. The first
mentioned has the v/idest distribution, from the Pemigewasset valley to
the Green hills of Conway in one direction, and from the Sugar Loaves
in Carroll to Tamworth in the other. It is also the most abundant in the
East Branch and Saco valleys. ,

The principal Albany granite areas are these, and they fall mostly
within the outer line of the Conway: i. Mts. Welch and Tecumseh.
2. From Mt. Osceola northward across the east branch above Pollard's,
branching at Mt. Liberty, most of it passing north-easterly, encircling the
porphyry of the Twin range, crossing New Zealand river, and divided
into two parts by Mt. Tom. 3. A very small area in the north-east cor-
ner of Campton. 4. North of Mt. Carrigain. 5. East of Tripyramid in
Waterville, 6. Occupying the principal part of Albany, passing northerly
into Jackson, and easterly beneath Mt. Pequawket. 7. In the north part
of Jackson. 8. West part of Chatham. 9. North-east part of Jackson
(Mt. Sable). 10. Dykes between Tin and Thorn mountains in Jackson,

Further study continues to increase the bounds of the Chocorua group.
The largest and most irregular is the one having Mt, Chocorua for its
main elevation, with a narrow spur reaching nearly to the Saco on the
north, and a broad overflow to the south in Tamworth. The others most
important are the Whitcface-Passaconnaway, Silver Spring and Tremont,
Giant's Stairs and Resolution, and one not mapped out embracing Frank-
enstein cliff. There are also smaller ones in Jackson and Chatham.

0. Pcquaivkct Breccia. The production of this breccia is the latest

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 263

occurrence of moment in this district. Its paste bears some resemblance
to the Albany granite. Inasmuch as fragments of porphyry occur in it,
the ejection of the paste must have been subsequent to the pouring out
of the compact feldspars over the Mts. Twin, Lafayette, Tom, Carrigain,
and other areas.

Last Period of Elevation.

We have already described a very important period of elevation at the
close of the Montalban period. There have been two later ones in Pal-
eozoic times of considerable importance, of which little is known. The
first is the disturbance which performed most of the elevatory work upon
the andalusite slates of Mt. Washington. It was probably coeval with the
eruption of the Pemigewasset granites. Such an enormous amount of
melted matter came forth at this time, that the convulsions attendant
upon it must have equalled those occurring at the close of the Montal-
ban period. Upon examining the strata in western New England, we
find evidence of upheaval at about the close of the Lorraine period. This
may have been the same with the one in question. It is the most prob-
able one of all that are known to have elevated our formations.

The latest epoch of elevation in these comparatively early times must
have occurred in the Devonian era, and it was one of great importance.
All New England and the middle Atlantic section was deeply submerged
before the deposition of the Helderberg limestones. The widespread
coralline limestones throughout this section indicate this, and we can
find no evidence of a greater submergence after Eozoic times. This
section must have been vigorously crowded after the deposition of the
Helderberg rocks, since they have all been elevated at a considerable
angle. They stand vertical in Littleton, and as high as seventy-five de-
grees in many parts of northern Maine. In that state we find resting
upon them, at small angles, the middle or upper Devonian sandstones. I
find I have remarked concerning those that are developed near Eastport,
in my first report upon the geology of Maine, that "they seem to have
been spread over the Silurian [Helderberg] rocks, just as alluvium is
spread over the solid ledges." There is positively less inclination to
many of these sandstones than to the Connecticut Valley sandstones of
a much later age.

Now, as the Helderberg rocks occur at a considerable distance from

264 STRATIGRAPHICAL GEOLOGY.

Mt. Washington, it may be tliat this elevation would hardly effect much
alteration in the andalusite strata, or no more than is evidenced by the
smaller curves along the carriage-road. But the amount of disturbance
upon the Hcldcrberg rocks themselves, in the edge of the mountains,
was enormous.

The attempt to localize in time these several disturbances is quite un-
satisfactory, as our data for generalization are so meagre. These sugges-
tions may be regarded as merely inviting the attention of scientists to
the problem. Some would doubtless prefer to refer one of these epochs
to the Appalachian revolution, at the close of the Carboniferous, or to an
earlier one at the beginning of the same era. I have thought these latter
disturbances inapplicable to the mountains, since none of the upper De-
vonian or Carboniferous beds occur within a hundred and fifty or two
hundred miles of them ; and their foundations had probably become well
fixed before these dates, so that they were not sensibly affected by either
of the Carboniferous convulsions.

EozoiG, OR Paleozoic?

The proper place for presenting arguments in favor of the Eozoic or
the Paleozoic age of the White Mountain rocks will be at the end of the
subject of Stratigraphical Geology; but our present expression of opinion
would not be complete without a brief statement of the principal argu-
ments upon both sides of the question, whether the bulk of the White
Mountains belongs to the Eozoic or the Paleozoic system.

As seen by the review of opinions, the first theorists accepted the view
that these rocks were Primary or Eozoic. Subsequently it became fash-
ionable to call them all altered or metamorphic Devonian or Silurian, for
these reasons: — i. There is a marked lithological difference between the
Adirondack and White Mountain gneisses. 2. The north-easterly unal-
tered continuation of the formations consists of Devonian and Silurian
groups; — therefore the White Mountain rocks are the same in a meta-
morphic condition. 3. In proceeding south-easterly from the St. Law-
rence and the Adirondacks, the strata dip easterly most of the way to
the sea-shore. Therefore we rise in the geological scale after leaving
the Laurentian; and hence the White Mountain rocks must be Devo-
nian, as they follow the Silurian of the Champlain valley. 4. A section
from Labrador across the peninsula of Gaspc to Nova Scotia carries us

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 265

from the Laiirentian to the Carboniferous ; hence, as we have both these
formations at the same distance apart — a few hundred miles along the
Hne of strike — the intermediate strata in New England must be the
same with those in the British provinces, or the Paleozoic in a metamor-
phic condition. There may be other considerations ; but these are the
most important, and are the ones which have carried conviction to many-
minds. As the process of metamorphism is supposed to be capable of
modifying the mineral character of rocks, whether by abstracting, alter-
ing, or adding constituents, it has afforded a very convenient method of
explaining why there should be little or no chemical resemblance betvv^een
the original and derived strata.

I would answer the arguments as follows, in the same order: — i. We
accept the difference between the Atlantic parts of the White Mountain
series and the Laurentian, while insisting that the latter is represented
in our two oldest groups. The Atlantic and later rocks are not repre-
sented at all in Laurentian regions. 2. We have presented the results
of special explorations in north-western Maine (pp. 204-209), which en-
tirely disprove the assertion of the passage of the Gaspe into the White
Mountain rocks. 3. The dips, in proceeding south-easterly from the
Adirondacks, are uniform to the east in many sections. Where this is
the case, it simply proves inversion. If the strata have been inverted,
then we descend the scale of formations instead of rising ; and therefore
the Green and White Mountain rocks are older than those of the Cham-
plain valley. Furthermore, many sections display a number of axes in
pursuing this course, as is illustrated upon Plates II, III, and IV. In the
Vermont report there are fourteen sections crossing the Green Moun-
tains. Eight of these show distinctly an anticlinal structure for the
Green Mountains, the most clear cases being in the Winooski and La-
moille valleys, where rivers have cut through them to their base. Two
others possess the same structure, as learned by careful reexamination of
their routes since the printing of the report. Of the four others, all are
monoclinal, — that is, have an inverted dip. 4. If the argument held good,
we should not find the Paradoxidcs in a slate adjacent to the Carbonifer-
ous in Massachusetts, since the formation containing the trilobite is older
than anything in the Champlain valley.

The following considerations are strong arguments in favor of the
VOL. II. 34

266 STRATIGRAPHICAL GEOLOGY.

Eozoic age of the Green and White Mountain gneisses: — I. They are
the northward continuation of the Eozoic rocks of New Jersey, the high-
lands of New York, and their extension across the Connecticut hne. We
can trace them all the way from Alabama to Canada, — twelve hundred
miles, — and they are flanked by the same broad, fertile Cambro-Silurian
Appalachian valley on the west side all the way. An orographical map
of the coast regions of America will show this fact in a very satisfactory
manner. If the valley formations are the same through East Tennessee,
the great valley of Virginia, the limestone region of Pennsylvania, and the
Berkshire and Champlain valleys of New England into the St, Lawrence,
why should not the adjacent and continuous highlands, on their eastern
border, have been formed essentially in one and the same period, espe-
cially as they have been almost universally regarded as Eozoic south of
Connecticut ?

2. Almost all the way the gneisses are bordered by a quartzite, usually
regarded as of Cambrian age. North of Adams, in Massachusetts, I have
examined four localities of a conglomerate connected with this quartz,
containing pebbles derived from the ruins of the formations to the east.
I suppose the whole mass has been derived from the same source, but
the fineness of the materials prevents its recognition. It should be re-
marked that there are no other formations from which it could have been
derived, save the Adirondack-Laurentian, which is from twenty to a hun-
dred and fifty miles distant.

Two considerations are derived from the study of New Hampshire
rocks, 3. The discovery of the Labrador system, overlying the most
abundant and characteristic White Mountain strata, makes it clear that
the latter are older than the former, which are confessedly Eozoic, 4.
Fossiliferous Helderberg strata occur on the extreme west and north-
east of the White Mountains, the latter in Maine, There are no other
groups so likely to be metamorphosed into the Montalban schists as
these, yet they occur side by side with the metamorphic schists, with
their fossils. The schists occupy the elevated tracts, and they consti-
tuted the continental dry land when corals luxuriated in the calcareous
waters of the deep Connecticut Valley sea.

5. The identification of the two oldest White Mountain groups with
the Laurentian is satisfactory, so that a portion of the debatable terri-

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 26/

tory is removed to its proper place in the Eozoic. 6. There is no cor-
respondence between the White Mountain rocks and those of any part
of the Devonian formations with which they have been compared, either
lithological or stratigraphical. Our predecessors became so enraptured
with the "New York system," that all the rocks in the adjacent states
were supposed to constitute a part of it. 7. The late satisfactory refer-
ence of the altered Quebec group to the Huronian has shed a flood of
light upon the age of our rocks, and rendered still more unnecessary the
application of extensive and extreme metamorphism to explain the age of
the White Mountains. As there seems to be an unreasonable opposition,
in some recent publications, to the existence of a Huronian system, I will
discuss its claims to recognition in the next chapter.

Appendix to Chapter III.

During the preparation and printing of this chapter, great improvements have been
effected in the delineation of the topography and the establishment of the nomencla-
ture of the White Mountains. The past year has witnessed nearly as great advance in
these particulars as the whole accumulated surveys and traditions of previous years had
amounted to. All this material has been employed in the preparation of our topo-
graphical model of the state, — upon the scale of one mile to an inch horizontally, and
one thousand feet to the inch vertically, — designed for exhibition at the Agricultural
college, Hanover, and the Normal school, Plymouth. The basis of the model is a con-
tour-map, upon the same horizontal scale, showing all the approved and newly-sug-
gested names. The attempt is being made to reproduce, by means of a heliotype or
photo-lithographic sheet, the effect of this raised map — with what success will appear
in the Atlas. As this is the last opportunity we shall have for speaking of the topog-
raphy of the White Mountains, I deem it proper to mention here this map-model, and
the additional sources from which the information for it has been derived, chiefly dur-
ing the year 1875.

I. The Portland & Ogdensburg Railroad has been completed through the heart of
the mountainous district ; and the engineer-in-chief has allowed us to make use of all
the data collected by him for the building of the road. Concerning the great value of
the excavations to the study of the formations, I have spoken heretofore. 2. Prof.
E. C. Pickering, of the Massachusetts Institute of Technology, with several of his
students, especially John B. Henck, Jr., spent the summer of 1875 among the moun-
tains, and carefully studied their topography. Mr. Henck carried a plane table upon
many of the higher summits, and succeeded admirably in locating their positions upon
a map. These gentlemen have kindly allowed us the use of all their results, which have
seemed to us to exceed in accuracy the work of Prof. G. P. Bond, which had previously
been made the basis of our maps. 3. Miscellaneous sources, — as a few observations of

.268 STRATIGRAPHICAL GEOLOGY.

the geodetic connection survey; surveys of property lines, by George T. Crawford, of
Bristol ; perambulations of M. F. Sweetser, in preparing a guide-book ; decisions of
the new Appalachian Mountain Club ; the regular work of the geological survey, etc.

A few friends of mountain exploration have united in the formation of a club, whose
object is the study of comparative geography, and the scientific and esthetic exploration
of the highlands of New England and the adjacent regions. The first field of their
labor will be the White Mountains. They propose the preparation of accurate topo-
graphical maps of this region, making new surveys, and carefully studying ancient and
modern records in search of the proper appellations to be applied to the several geo-
graphical objects. At a meeting held in January, 1876, the subject of nomenclature of
our mountains was discussed, and many excellent points made. The club voted to
adopt a revised nomenclature, based mostly upon the map of the geological survey.
On account of the influence which this club will be likely to exert hereafter, I have
thought it best to adopt their names upon the map-model in the atlas, and hope the
effort to establish a judicious nomenclature will be followed with success. Not all the
names used by the geological survey meet their approval. Their canons embraced the
following points : first, names of well-established usage should remain ; second, in case
of disputed euphonious titles, that which has been longest known or was applied first,
should be adopted ; third, in proposing new designations, the best classes to be selected
from are the names of Indian chieftans formerly residing in the state, of the early ex-
plorers of the mountains, of persons who have identified themselves with the develop-
ment of the district, or marked resemblances to hills in other regions. They did not
attempt to name all the eminences in this way — only the most prominent. For the
whole group they adopted a division according to area and altitude, which will be
explained in the appendix to this volume, where the geographical positions of all our
New Hampshire mountains will be stated by Prof. Pickering. I will mention, following
the topographical subdivisions of the White Mountains proposed in the first volume,
the most important suggestions and adoptions of this club, and, where there has been
a change from tlie usage of the report, state it, so that no ambiguity may arise froni
the employment of one designation upon the map and another in the text. It will
certainly be a great gratification to all who are interested in the mountains'to know
that so much pains are taken by the friends of mountain exploration to render our
scenic points attractive in title and easy of access ; for, among other objects, the club
propose to make paths to new summits, and interest tourists in every nook and dell,
ridge, ravine, and summit.

In Northumberland the original name of Cape Horn was thought to be singularly
appropriate, and therefore its replacement by Mt. Lyon, as suggested in the geological
report, uncalled for. There are several improvements in the Mt. Carter district. Mt.
Winthrop is a new name for a moderate eminence south-east from Shelburne village.
Mt. Carter is tlic central mountain of the range, a little north of cast from the Glen
house (4702 feet). Imp mountain, Mt. Moriah, and Bald mountain lie to the north-east,
extending into the town of Shelburne. In the south-east corner of Bean's Purchase

GEOLOGY OF THE WHITE MOUNTAIN DISTRICT. 269

the names of Wildcat and Carter Dome were adopted for the mountains on the south-
west and north-east sides of Carter notch, the last being the soutliern end and the
highest (4830) part of the unbroken Carter range. It replaces Mt. Height. Mts. East-
man and Sable have been altered somewhat in position. Mt. Slope in Chatham should
be written Sloop, in accordance with local usage since the days of Belknap's (1791)
map. Perkins notch, between Wildcat river and Wild river, is now for the first time
placed upon a map.

There may be several additions to minor topographical features upon Mt. Washing-
ton. Cutler's river seems, according to the best judgment, to be the same with Ellis
above the Pinkham road, New river being between this and Glen Ellis fall. Hunting-
ton's ravine was improperly described on page 188. It is the second ravine parallel
with and north of Tuckerman's, tributary to the valley called by that name in the first
volume. Pine hill, formerly Camel's Rump, has become Pine mountain. Hart's moun-
tain is properly the steep bluff just above Wilkes's ledge, opposite Sawyer's rock, but,
as I have applied it to the summit of the range opposite Nancy river (not brook), I
think it best to leave it as pertaining to the whole range. Wilkes's ledge is often im-
properly called Hart's.

Owl's Head, at tlie north end of Cherry mountain, has been styled Mt. Martha, and
the name adopted by the geodetic connection survey. The Willey range, from its
beginning near the White Mountain house as far as Mt. Tom, may be known as the
Rosebrook range, the highest peak to the south being identified now with the Mt. Echo
of Guyot. Mt. Andalusite is a small eminence on the north-east flank of Mt. Tom.
Mt. Field was adopted by the club for the high mountain south of Tom, and its north
spur (p. 177) maybe known as Mt. Avalon. Thoreau falls designates the "falls on the
north branch of the east branch of the Pemigewasset." Mt. Anderson is the name of
the i^ointed summit between j\Its. Lowell and Nancy, after John F. Anderson, of Port-
land, engineer-in-chief of the P. & O. R. R. Vose's Spur is applied to the very sharp
peak between Carrigain notch and Mt. Carrigain, after Prof. G. L. 'Vose, of Brunswick,
Me., one of the former assistants on the geological survey. Passaconnaway and Tri-
pyramid are accepted for the mountains thus called by us. (See p. 211.) Mt. Kancam-
agus is proposed for the unnamed mountain just east of Greeley pond ; Mt. Paugus for
the highest peak between Mts. Chocorua and Whiteface ; and Mt. Wonalancet for what
has been known as Toad mountain.

The mountains around Upper Bartlett are now coming into prominence, with the
increased facilities for their ascent. From the cliffs near the mouth of Rocky Branch to
the neighborhood of Mt. Crawford, east of Razor brook and north of the Saco, is the
following array of names : White's ledge, Mts. Stanton, Pickering, Langdon [Black-
well] , and Parker. Willoughby ledge is at the east angle of Razor brook and Saco river.
On the south, there was not such a unanimity of sentiment as to names. Jl/oaf seems
to have been the original spelling of the high mountains west of Conway. Silver Spring
mountain having been applied to the summit rising back from Sawyer's rock by Prof.
Bond, in 1853, has since then been adopted by Guyot, Snow & Bradlee's model, and

2/0 STRATIGRAPHICAL GEOLOGY,

the geological sui-vey. Owing to engravers' errors, its position has not been clearly
understood ; but an inspection of the original manuscript of Bond's map removes all
doubt as to its application to the peak just spoken of. Table mountain appears first on
Guyot's map, another name being Bear. On looking at this elevation from Mt. Willard
and other peaks to the north, the appropriateness of the name Table for this mountain
is very apparent. A small peak to the north-east of Moat, showing square, precipitous
sides towards Jackson, has been designated as Mt. Attitash, after the Indian name
for blueberries.

In the Twin Mountain range, it has been proposed to commemorate Guyot and Bond
in the two most southerly peaks, about a mile ajoart, Bond being the one farthest south.
In Campton, Mt. Weetamoo (misspelled on p. 204) is a new name for the mountain
west of Sandwich notch. Beech hill in Carroll and Bethlehem is beginning to be called
the Sleeping Giant. Peaked hill in Bethlehem is known to the residents as Mt. Agassiz.
Black mountain in Benton, the one nearest Moosilauke, is named Mt. Clough, in honor
of the late Amos F. Clough, of the Mt. Washington expedition. There are already
several Black mountains, so it seems strange that there should be a desire on the part
of any to retain this appellation for Sandwich Dome, Eagle lakes is a revival of Guyot's
term for the Lakes of the Clouds upon Mt. Lafayette. Tamarack pond (p. 158) is now
known as Mouran lake. (See vol. i, p. 504.)

Much was said at the meeting of the club about the use of the term Pequawket for
the mountain in Chatham, sometimes called Kiarsarge and Kearsarge. Confusion
arises from its similarity to Kearsarge in Warner, whose claim to the name has never
been called in question, while its application in Chatham has been discussed for more
than half a century. Two mountains, only sixty miles apart, should not in these days
of rapid transit be known by the same name. In this juncture, therefore, the question
becomes one of priority. Examination of the maps shows the application of the name
to the Warner mountain by Blanchard and Langdon in 1761, and by Holland in 1784
(see Atlas), while nothing appears for the Chatham peak. Belknap's map in 179 1, and
others of 1796, first show the application of the name to the latter mountain. In this
connection it is proper to state why it was ever proposed to call Pequawket Kiarsarge.
It appears probable that the Conway pioneers came chiefly from Concord, and that
they brought the name of their favorite mountain with them. It is certain that the
names of the leading families in Conway, in early times, agree with many of those in
Concord. Usage has by no means been unanimous in favor of Kiarsarge for Chat-
ham. Dr. Jackson, in his geological report, Carrigain, in the state map of 1816 (see
Atlas) , and the United States Coast Survey use the name of Pequawket. The usage
in Conway and Bartlett is divided between the two. In view of these considerations,
the members of the club present at a late stage of the meeting voted to recommend
the following formula, and use the name in brackets only because of the strong feeling
manifested in its favor by its partisans — Mt. Pequawket [Kiarsarge]. But the hope
was expressed that the bracketed title would eventually disappear.

CHAPTER IV.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

fHE Connecticut Valley district is separated from the rest of the
state by features mainly dependent upon geological structure. The
eastern border line is not the water-shed between the Connecticut and
Merrimack rivers, but the boundary between diverse systems of strata,
giving rise to agricultural and topographical peculiarities. This region
is limited northerly by the crossing of the valley by the Gardner Moun-
tain range, giving rise to the "Fifteen-miles falls," between Monroe and
Dalton, the river descending three hundred and seventy feet, or one hun-
dred feet more than from the falls to the Massachusetts line, a distance
of one hundred and thirteen miles in a direct course. The eastern bound-
ary follows the line between the Coos group and the Atlantic gneisses.
This usually conforms with the summit or eastern base of a mountainous
range of quartzite. The northern and western boundaries coincide largely
with the hydrographical boundaries as far south as the granite mountains
east of Montpelier, and then include the greater part of the calcareous
formations in eastern Vermont. These are narrowest by Mt. Ascutney,
opposite Cornish, so that a natural primary division of the area into two
parts is suggested by this constriction.

The soils of this district are of three kinds : first, those on the fertile
meadows of the Connecticut and its principal tributaries; second, the
rich uplands of the calcareous districts, comprised chiefly within the
western side of the river, while constituting areas of variable size on the

272 STRATIGRAPHICAL GEOLOGY.

New Hampshire border, as in Cornish, Claremont, Lyme, and Orford ;
third, the upland tracts underlaid by the micaceous schists and quart-
zites. These varieties result from the character of the ledges ; and, as
stated heretofore, the soils of the Connecticut valley are among the best
in the state.

For convenience in our descriptions, the rocks of this district will
be described under four topographical divisions : first, the Ammonoosuc
Gold field ; second, the balance of the northern section, extending suffi-
ciently far south to embrace the Mt. Ascutney rocks ; third, the southern
section of the district from Charlestown to Chesterfield, opposite Brattle-
borough, Vt.; fourth, the Helderberg region, embracing Hinsdale, part of
Winchester, Vernon, etc., Vt., and parts of Northfield and Bernardston,
Mass. Whatever facts we may happen to possess respecting the rocks
of the western part of the district, in Vermont, will also be presented,
though our information of that part of the area is not extensive. Enough
is known of the rocks on the western side of the river to render feasible
the presentation of the geology of the whole district. The boundaries of
states are not usually the natural limits of formations, so that we must
trespass a little upon the Vermont territory. Our general geological map
will be seen to extend into that state about the width of two townships,
except in Essex county, where more land is included. We have been
enabled thus to extend our map, through personal investigations in con-
nection with the Vermont geological survey, and more recently in contin-
uing our section lines across to Lake Champlain, for the benefit of the
museum.

THE AMMONOOSUC GOLD FIELD.

This field embraces the territory bounded west by the Connecticut
river, north by the town of Dalton, cast and south by the older gneissic
areas, or from the west border of Bethlehem, through the eastern parts
of Lisbon and Landaff, to the northern part of Haverhill, and thence to
the Connecticut river. This embraces the whole of the towns of Little-
ton, Monroe, Lyman, Bath, and parts of Haverhill, Landaff, and Lisbon.
It is all expressed on the small geological map in the first annual report
(1869), and also in Fig. 27. The large map in the Atlas docs not quite
cover the whole ground, it being confined to the space between the

GEOLOGY OF THE CONNECTICUT VALLEY DLSTRICT, 2/3

Connecticut and Ammonoosuc rivers, and not including the whole of the
Helderberg area of Littleton.

The following are the rock formations displayed in the Ammonoosuc
Gold field, arranged in the supposed order of their age: i. Laurentian,
consisting of the porphyritic and Bethlehem gneisses. 2. Atlantic gneiss,
represented by the Lake division. 3. Huronian, embracing the Lisbon
and Lyman groups and the auriferous conglomerate. 4. Cambrian clay
slate. 5. Coos grouix 6, Swift Water series. 7. Helderberg quartzites,
slates, and limestones.

The general arrangement of these formations appears in Fig. 27. The
first two gneisses of Laurentian age border the field upon the north-east;
and the second is probably repeated in Haverhill, though not here sepa-
rated from the following division, which borders the field most of the
way upon the east side. A spur of this Lake gneiss divides the Coos
group for a couple of miles in the north-east part of Lisbon. The west-
ern part of the field is a basin of the Lisbon group holding the upper
Huronian, clay slate, and Helderberg, the Coos group being confined to
the region east of the Ammonoosuc. The clay slates occupy two lines
of outcrop, separated by the Lyman group. The more eastern one is
auriferous. The Coos group is isolated from all connection with its kind,
being separated from its northern continuation on account of the eleva-
tion of a range of Bethlehem gneiss. The Helderberg series appears to
follow the course of a mountainous ridge along the centre of the field,
lying principally in Littleton. The map was constructed primarily for
the sake of portraying the peculiarities of these rocks, — hence all the
section lines upon it are seen to cross this area. A sketch of the Hel-
derberg rocks of New Hampshire has been published by us in the Amer-
ican yoiirnal of Science and Arts, for May and June, 1874, in which Fig.
27 appeared ; and it is used now, with the approval of the editors of that
magazine. We are also able to present additional information concern-
ing these rocks, and the other formations arranged about them.

I. Laurentian.

Very little needs to be said concerning the Laurentian areas, as they
just touch the borders of the field, and have been amply discussed else-
where. The porphyritic gneiss area occurs at the corners of the towns
VOL. n. 35

2/4 STRATIGRAPIIICAL GEOLOGY.

of Littleton, Whitefield, Bethlehem, and Dalton, forming an oval-shaped
isolated area of about four square miles in extent. The Ammonoosuc
flows along its eastern border ; and there is a large hill in the western or
central part, about six hundred feet above the river. This area is the
most northern exposure of the porphyritic gneiss in the state. It is sup-
posed to be connected with the great Lafayette-Moosilauke range be-
neath the overlying Bethlehem group, and to be the oldest formation in
New Hampshire.

The determination of the dip of this rock near the Wing Road station
has been a difficult matter. There are jointed planes, with scarcely any
inclination that might be taken for strata. At the suggestion of Dr. T.
Sterry Hunt, a crystalline arrangement of materials dipping 75° S. 40°
E. was decided upon to represent the strata. The first set of nearly hor-
izontal divisional planes presented no variation of mineral composition,
but the second exhibit an alternation of coarse gneisses, fine feldspathic
layers, and other varieties, separable only by a difference of character.
They are also more irregular than the others. The gneisses show two
feldspars, — orthoclase and oligoclase, — two micas, — muscovite and bio-
tite, — and amorphous quartz. On the north town line of Bethlehem, and
at the west base of Kimball hill, I found a ledge of the rock having in it
a gneissic seam, two inches thick, dipping 25° N. 20° W. The hill west
of the Ammonoosuc, sometimes called Bald hill, is composed of a bare
ledge of this rock. It is most conspicuous as seen from the village of
Bethlehem, and is a spur of Mann's hill, with but a slight valley between.
The feldspar crystals are conspicuous on Mann's hill, near the junction
with the mica schist, and the dip is about vertical, perhaps 70° N. 75°
W. It is presumed this rock outcrops in the south-east corner of Dalton.

The south-western mnd of the most imj^ortant area of Bethlehem gneiss
projects into the Ammonoosuc field, crossing the river just above North
Lisbon. The dip is unusually low on the river, being only 30° northerly.
At the "lead mine" the dip is 36° north-west. Farther to the north-east
the dip rises to 75°. As the strata are monoclinal, from an inversion, it
is difficult to determine whether the axis is anticlinal or synclinal, with-
out reference to other parts of the terrane. It would seem to be an over-
turned synclinal, when all parts of the terrane have been compared with
each other and the adjacent formations. The angle of inclination is less

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

275

276 STRATIGRAPHICAL GEOLOGY.

than that of the newer formations upon both sides. Hence it is believed
there is an unconformity, the older rock really possessing a greater angle
of inclination, as we must add to its present dip 90"^ for inversion. The
hill east of North Lisbon is covered heavily with drift; and explorations
have not been made extensively away from the road, so that our dip
observations there are scanty.

The upper layers, or outer border of this area, are different from the
characteristic Bethlehem rock, containing an abundance of black mica in
place of the chloritic mineral, and occasionally lacking an abundance of
feldspar. Some layers are epidotic. In my first article this narrow outer
band was referred to the next division of gneiss. It is better to place it
in the Bethlehem group, partly because of its recurrence in the older
rock in terranes lower down on the Connecticut river. The map shows
a small outcrop of this member just below the mouth of Salmon Hole
brook, nearly on the line of the continuation of this formation. I have
sometimes thought it passes from this locality to the Atwood gold mine,
a mile east of Lisbon village. The dip at the first-named place is in-
verted. As the same formation appears in Haverhill, it may be contin-
uous near the surface from Bethlehem, If so, it may determine axes in
the later formations.

2. Atlantic Gneiss.

This belt is the south-west continuation of the Berlin-Randolph and
Whitefield ranges. The first lies mainly to the east of the Coos group
in Lisbon and Landaff, belonging to the territory assigned to the Merri-
mack topographical district. The latter is nearly cut off by the Wing
Road porphyritic gneiss, and spreads out more largely in the east part of
Littleton. The village seems to lie upon it, though covered by coarse
drift, and having micaceous c|uartzites in the river. Mann's and Oak
hills furnish the first exposures of this gneiss. No evidence of its exist-
ence beyond Parker brook has yet been discovered. The narrow band
of gneiss in Fig. 27, encircling the Bethlehem gneiss from Factory vil-
lage to North Lisbon, and thence beyond Streeter pond, is included with
the latter formation constituting its upper member. The north-westerly
dip is universal over the western area of this gneiss. There is first its
representation on Fig. 11 for Whitefield. Between Bethlehem Hollow

GEOLOGY OF TKE CONNECTICUT VALLEY DISTRICT. 2//

and the Wing road the position is 80° N. 42° W. Oak hill shows the
dip of 40° N. 42° W. The inclination is like this a quarter of a mile
north of the Littleton cemetery, at E. P. Miner's. I think the dip is
higher at the most northern development of the gneiss, on Mann's hill.
Common gneiss and hornblende schists are interstratified there. Two
of the sections soon to be presented show this gneiss in its relations to
the chloritic strata, it being ajDparently beneath them unconformably.

3. HUKONIAN.

This formation exists in this field in three parts, — the Lisbon and
Lyman groups, and the auriferous conglomerate. The two first are sep-
arated upon Fig. 27, and were described for the first time, under these
appellations, in the article cited above. The first is the lower division,
embracing the greenish schists, conglomerates, copper-bearing strata,
quartzites, jaspers, and dolomites, usually referred to this age and re-
garded as characteristic of the group. This rock is disposed in a syn-
clinal way, dipping north-westerly where it is nearest the Atlantic gneiss,
upon the east side of the basin, and south-easterly upon the west side, or
on Gardner mountain. The upper series is inclosed within the limits
of the Lisbon group, and consists of drab schists, mostly of silica, with
small percentages of iron, lime, and magnesia, and weathering very light,
so that in the field we called them "white schists." Many ledges are
conglomeratic, the pebbles being mostly elongated, and composed of es-
sentially the same material with the mass of the formation. Dolomite is
especially abundant in it. The uppermost member is a conglomerate of
siliceous pebbles, never exceeding two hundred feet in thickness. It is
called auriferous, because assays of it in several places indicate the pres-
ence of a small amount of gold. Irregularities of direction and faults
are beautifully illustrated by the areas occupied by this member, as will
be particularly described. Though somewhat thrown out of place, the
general arrangement of the Lyman group and the conglomerate is that
of subordination to the Lisbon series, or a synclinal arrangement within
the limits of the latter.

In order to illustrate the relations of the three members of the Huro-
nian system to each other, and to the underlying and upper strata, I will
insert a section showing the outcrops between Bronson's lime quarry, in

2/8

STRATIGRAPHICAL GEOLOGY,

y cj

Lisbon, to Smith's brook in Lyman, giving, also, the thicknesses as meas-
ured on this hne.

At the south-east end of the section there are the ordinary gneisses of
the Lake division, dipping about N. 30° W., and holding a band of azoic
K CO- ^ limestone, perhaps one hundred feet thick, inclined
50°, which has been extensively quarried by Mr. Orrin
Bronson. On the hillside toward the pond are fria-
ble gneisses, often very micaceous and carrying crys-
tals of staurolite, dipping 30° N. 70° W. This is bor-
dered by a band of hornblende schist dipping in the
same direction : 40° is the average for its whole width.
^ The hornblende is an associate of the gneiss forma-
H tion rather than of that which follows. The estimated
.g thickness of this gneissic group, between the lime-
^-. stone and Mink pond, is 2500 feet. This assemblage
^" of gneisses and associated rocks west of the limestone
^ is slightly suggestive of the Montalban member of the
I Atlantic system. On the north side of Mink pond is
I a gray, friable mica schist, holding in profusion the
^ reddish staurolites and garnets, the locality being one
M well known to mineralogists. The average dip being
'> 56°, the thickness must be 3300 feet. This band is

1 6 followed by the same garnetiferous slates which occur

2 I upon the south branch of the Ammonoosuc. Stauro-
■■ .5
s''^^ lite is less abundant in this than in the previous band,

" " and it is almost wanting in the western portion. With

J s '^ ^

;3 I an average dip of 58°, this slate must be over 3000

"^ '^ feet in thickness. This all belongs to the Coos group.

e ^ The Swift Water series follows. For one hundred

.X I and forty rods there are quartzitcs and sandstones,

■f, I with an average dip of 50°, which gives 1769 feet in

t' J thickness. More particularly, an excavation for gold

^- r. at the eastern border shows slaty layers, quite sili-

li ccous, with sandstones considerably vitrified. Next is

1 1 a sandstone, with whitish cement. Then there are in

= i order actinolite schist, hornblende schist, while mica

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 2/9

schist, and sandstone. For twenty rods beyond, the rock is purely horn-
blende, and is three hundred feet thick. The strata are concealed for
one hundred and eighty rods along the line of section, which must be
2400 feet thick, if their inclination agrees with those upon both sides.
Just beyond is a black slate, exposed at a railroad crossing at the north
end of Lisbon village, which is the last member of the series, and it has
been traced along the strike for ten miles, from the south part of Lit-
tleton to the line of Haverhill. The total thickness of the Swift Water
series on this section seems to be over 4400 feet.

The Lisbon group begins a little east of the village of Lisbon, and
reaches into Lyman. The following are the kinds of rocks seen : first,
hydro-micaceous conglomerates, — 756 feet; second, hydro-mica schists,
with cupriferous layers, — 3539 feet. The upper division often carries a
nodular mass of nearly white quartz, from fifty to one hundred and fifty
feet thick. A little to the south of the line of section, and observed very
largely elsewhere, is an aggregate of feldspar and chlorite. It is the
same with that adjoining the Helderberg rocks in Littleton. The fault
which has nearly cut off the Lyman group on the section has caused this
rock to disappear beyond the south corner of Lyman.

The Lyman group has a thickness of only two hundred feet adjacent
to the fault. It is entirely wanting a quarter of a mile farther north.
Beyond the slates it has a thickness of 2330 feet, allowing it to be folded.
The clay slates next succeeding are 1500 feet (possibly 1800) thick. They
contain the well-known auriferous quartz vein worked at the Dodge mine,
yielding, in its better parts, from $15 to ^25 to the ton. They resemble
closely certain auriferous rocks of Nova Scotia, referred to the Lingula
flags of Great Britain by A. R. C. Selwyn, geologist to the Dominion of
Canada. In composition it resembles the Lyman schists, and may have
been derived from the breaking up of the latter. A study of the struct-
ure of the Cambrian slate over the Ammonoosuc area shows it to be a
synclinal. I have followed it carefully, from the unmistakable basin form
in Bath, to the inverted monoclinal dip of the section line. There is
very little variety of lithological character in this series.

After passing the slates, the largest area of Lyman schist in this field
presents itself. Near its eastern border are large lenticular-shaped beds
of quartz, some of them thought to be auriferous, and certainly associ-

280 STRATIGRAPHICAL GEOLOGY.

ated with veins carrying galena. Though high, the dip increases its
angle till the western border is reached. The auriferous conglomerate
and beds of dolomite are met with near the western border of the group,
the former being about seventy-five feet thick. Near Parker hill the Lis-
bon group reappears, dipping south-easterly. This undoubtedly unites
beneath the Lyman and Cambrian rocks, completing the synclinal. No
effort has been made to measure its thickness beyond Parker hill.

Detailed Maps. Of these there are two. One has been referred to in
Volume I, pages 22 and 46. This shows the result of a protracted survey
of four square miles in the south corner of Lyman, the principal object
being the accurate delineation of the formations with reference to aurif-
erous veins. The other embraces the country between the Connecticut
and Ammonoosuc rivers, and illustrates the topography of the region by
means of contours, with the locations of the several mining properties
Constant reference should be made to these maps for the purpose of
verifying our statements.

Lisbon Group. At the south end of the field in Haverhill there seems
to be only one range of the green schists, in proceeding north-easterly.
This constitutes the floor spread out underneath the whole Ammonoosuc
area, the subdivisions about to be indicated being produced by lines of
superior groups. In this subdivision we first separate the ranges on the
extreme borders, the western being the most extensive, and following
Connecticut river to Dalton. The eastern is continuous to the south
part of Lisbon, and then seems to pass under the Swift Water series,
perhaps unconformably, to reappear in a modified form on the south
branch of the Ammonoosuc, terminating at Streeter pond. For the last
part of its course, it adjoins the Bethlehem gneiss. Towards the interior
parts of the basin we find limited areas of the green schists. First, there
is one in the north-east part of Bath, running into Lyman. This may
be ranked as Lyman schist upon the map, as both the green and white
schists are represented within it. It is separated from the slates at its
blunt south end by means of a fault; and very fine specimens of con-
torted strata came from this dislocated line. Second, a small area has
been discovered in the blank space of Fig. 27, Bald hill, Lyman. Third,
there are two narrow bands in Littleton, crossing Parker brook, in the
midst of Heldcrberg exposures. F'ourth, I think there is a line of out-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 281

crop between the Parker Hill and Gardner Mountain lines of north-east-
erly roads, connecting the larger areas in the south-west part of Littleton
and in the north part of Bath. The two parts are separated by a narrow
range of clay slate, which is replaced by the Lyman group in Waterford
and Concord, Vt. We remark that the Lisbon group occupies a greater
area in this field than in any other part of the Connecticut valley south
of the Upper Ammonoosuc river. It is likely there was originally a
wider basin here, allowing of the quiet deposition of the upper forma-
tions, which are wanting farther south, at least continuously. The aver-
age dip of the strata is also less over this basin than in the district south
of Bath.

In noting these ranges I will begin with the eastern, commencing at
the south end of the clay slates. This is at the point where the forma-
tion divides into two parts. A road crosses it exactly along this line, in
company with a brook. The schists are not as green as usual, though
having a high north-westerly dip. Near the slate there is a large mass
of white quartz, extending certainly a quarter of a mile along the strike.
Lower down there is very much dolomite. Near the mouth of Perch
Pond brook the green schists dip north-westerly. Below Bath station,
on the railroad, the rock is conglomeratic, with blue quartz pebbles. A
mile from the station the schists dip y^° N. 48° W. The dip near the
Bath town-house is similar. The rocks are nearly the same as to variety
and position at the station. There is a conspicuous vein of white quartz
on the hill west. In Bath lower village are several enormous blocks of
hydro-mica schist, which probably indicate the character of the underly-
ing ledges. Similar rocks occur at a starch mill about a mile up the
Wild Ammonoosuc river, adjoining the Swift Water series. There are
green schists on the Lisbon road, about a mile north of the station, near
the top of the hill. Probably most of the rock in the easterly bend of
the river in this neighborhood is of the same sort. Near the mouth of
Smith brook it seems to be crowded on to the other side of the Ammo-
noosuc. Nearly opposite the strike is S. 75° W. At the mouth of Mill
brook, Landaff, there are green schists dipping 70° N. 42° W. With
this is a quartz vein, two feet wide; and the accompanying rocks are
slightly calciferous and pyritiferous. The ledges are well exposed at the
dam across the river, and also a little lower down. Half a mile below
VOL. II. 36

282 STRATIGRAPIIICAL GEOLOGY.

Lisbon there is a coarse conglomerate in the schists, the strata dipping
north-westerly.

These rocks are well developed through Lisbon. General statements
respecting them are given with the description of Fig. 28. The following
are the details of this, the best section I have crossing this band, from
Lisbon village to the town line west. The eastern limit is reached back
of the railroad, near a narrow band of clay slate belonging to the Swift
Water series. The green schists by the church contain a little limestone,
and dip 64° N. 62° W. In the river under the bridge are quartzites and
coarse conglomerates, quite suggestive of the Helderberg under the North
Lisbon bridge. The more western of these strata hold elongated and
flattened pebbles, with the dip 44° N. y^^ W. A few rods on the road
up the stream are green schists, with limestone seams, dipping 40° N.
60° W. Under the hill west, by E. C. Stevens's house, is a prominent
ledge of hydro-micaceous schists dipping 60° N. 30° W., and holding a
quartz vein carrying a little galena. At the edge of the woods the same
green schists dip N. 55° W. Near the top of the hill we find hard, green
pyritiferous schists that dip N.'6o° W.; at the very top, N. 70° W.; and
there is some easily-decomposing carbonate present in the rock. The
whole hill is composed of these green schists. On the western slope,
and near the cross roads, the dip is N. 65° W. The rock contains a little
galena scattered through the hill in minute particles. North of the line
of section a short distance, there has been an opening for copper ore.
The metal is present, though not in large amount; but the existence of
copper and lead, which are widely disseminated through these ledges,
suggests the similarity of the horizon to the richer veins of Gardner
mountain. On the west side of the by-road the schist contains horn-
blende and pyrites. Succeeding layers approach gray quartzite in com-
position, dipping 57° N. 55° W. About two hundred and fifty feet east
of the house of Jason Titus, the last member of the series makes its
appearance, — a mass of white quartz dipping 50° N. 55^? W., varying
from fifty to one hundred and fifty feet in thickness.

This bed of quartz is a matter of importance. There are four out-
crops of it along the same horizon, near the Lyman town line. The
most southern begins one thousand feet north of the road from Lisbon
over Gordon hill, and extends for six hundred and sixty feet in length,

GEOLOGY OF TH-^ CONNECTICUT VALLEY DISTRICT. 283

and about one hundred and twenty-five feet in width, having a lenticular
shape, and a north-westerly dip. The quartz resembles that occurring in
the Atlantic gneiss, breaking up into rectangular pieces, and somewhat
reticulated by small quartz veins. It forms a prominent feature upon the
north side of the road. The next two are smaller patches, on both sides
of the road near J. Titus's. The more southern runs into one of large size
upon the northern slope of the hill, that is very conspicuous as seen from
the road between Lisbon and the Dodge gold mine. The other exposure
is about a thousand feet south-west from J. Corey's house, on the last
road mentioned. It may be three hundred feet long and one hundred
wide. The clay slate butts against this quartz boss, having a dip of 43°
N. 20° W., and a sliding between the rocks is obvious. I cannot say that
this quartz is certainly represented beyond these limits; but suggest it
may be the equivalent of the large mass alluded to above, adjacent to
the southern end of the slate in Bath, and the beds upon Fitch hill in
Littleton.

This range of lenticular quartz bosses furnishes us with an excellent
example of unconformability between the Lisbon schists and the clay
slates. The first ledge lies on the line between the Lisbon and Lyman
groups, and is removed entirely from all connection with any areas of
slate, the nearest one being 1300 feet to the south-west, on the line of
strike. The next exposures, at Titus's, are 11 50 feet south-east from the
principal range of slate lying to the north-west of the range just men-
tioned, if it were prolonged. Near Corey's house the eastern border of
the slate — the direct continuation of that north-west of Titus's — is situ-
ated five hundred and thirty feet east of the quartz. We have therefore
a strip of quartz crossed transversely by the slate at an angle of seven-
teen degrees. The length of the quartz between the points measured is
nine hundred feet, and the sum of the easting and westing is 1680 feet.
In other words, the eastern border of the slate, which was 11 50 feet
north-west of the quartz at Titus's, crosses it, and lies 1680 feet farther
to the south-east, opposite Corey's, than it would were there no uncon-
formity. Evidence is afforded of a fault near Titus's ; but this does not
seriously affect the fact of unconformability, which is corroborated by the
common relations of the two formations explained in detail elsewhere.

There are other ledges along the Ammonoosuc river before coming to

284 STRATIGRAPHICAL GEOLOGY.

the crossing of the formation by the Swift Water series. There seems
to be a thick mass of schists and conglomerates crossing transversely
over the Lisbon series, in a different direction from that of the clay
slates just mentioned. It is difficult to understand the precise relations
of these rocks without further study. The green schists crojD out on the
opposite side of the last-named group at several places, as at the bridge
over the river where the railroad bends to the east, overlying the limited
outcrop of the Bethlehem gneiss.

There is a band of hornblende rock commonly separating the Huro-
nian from the Helderbcrg. Between Streeter pond and North Lisbon it
barely touches the Helderberg, but is a peculiar rock. It consists of an
aggregation of radiated crystals of diallage, with a finer paste, com-
posed largely of pyroxene. At the saw-mill, about a mile and a quarter
south of North Lisbon, it is an ordinary fine-grained hornblende rock.
This can be traced on the north-west side of the Helderberg into Little-
ton, cropping out at several places, particularly between D. E. Corey's
and the river near the line. At very low water it may be seen in the
Ammonoosuc, a mile into Littleton. It is next seen occupying the sum-
mit of Fitch hill, forming the ridge for half a mile. It is here a compact,
massive hornblende, with no indications of divisional planes traversing it.
I have thought these several outcrops may represent one geological hori-
zon ; and that it is associated with the feldspar and chlorite aggregate or
protogene gneiss, which is better developed in Lancaster. It seems to
cap the Lisbon group of schists. The dip just above North Lisbon, at
the South Branch, is 50° N. 20° W.; near the saw-mill it is 75° N. 50°
W.; about the same near the town line ; and probably vertical upon
Fitch hill, with a strike of N. 70° E. There is more of it at the very
south corner of Lyman, near the line of lenticular quartz beds.

In the south corner of Lyman the protogene rock (upper member) dips
35° N. 30° W. The rock bears a resemblance to elvan, and is more
compact here than usual. Half a mile above the ridge, in middle Lisbon,
there are hydro-micaceous schists, with a high north-westerly dip. At
S. K. Chase's there is a greenish conglomerate, with reticulated veins and
pyrites, dipping 60*^ N. 50° W. The band is about a mile in width here.
The clay slates join this group at Perch pond, the green schists on the
east side dipping SS^^N. 35°W. I cannot find evidence to connect

GEOLOGY OF IHE CONNECTICUT VALLEY DISTRICT. 285

directly the Lisbon schists in central Lisbon with those in Littleton, by
way of the Ammonoosuc. They belong to different ranges, connected
by anticlinal or synclinal axes. This eastern band seems to terminate
near Streeter pond.

Recent observations suggest the existence of a limited outlier of the
green schists on the south side of Bald hill, in the north corner of Lis-
bon. No ledges were discovered, but large blocks were abundant, and
among the pieces small boulders of jasper. The top of the hill and the
surrounding region show slates and Heldcrberg rocks. This band of
Lisbon rocks occupies a part of the space left vacant upon Fig. 27.

The western branch of the Lisbon schists, if properly understood, is
broader than the eastern. At Woodsville the strata dip 80° N. 40° W.
This observation may be taken to represent the usual position of all
the ledges in the south and west parts of Bath. North of Woodsville
the hills rise abruptly, almost precipitously, into the Gardner Mountain
range; and there are high cliffs adjacent to the Connecticut river at the
"Narrows," above the mouth of the Ammonoosuc, the rock dipping high
north-westerly. A trip from Bath lower village across the mountain to
Connecticut river (Fig. 29), shows on Child's brook greenish schists, dip-
ping 30° N. So'' W., of the eastern range. Next succeed the clay slates,
exhibiting considerable variation, — an anticlinal situated upon a synclinal.
Adjacent to the slates upon both sides, but especially on the west, the
schists resemble the micaceous quartzites of the Lyman group, near W.
Lang's, dipping 80° south-easterly. The dip has essentially the same
direction continuous across the mountain, but a smaller angle on the
west side. About one third the way up the hill the schists are ferru-
ginous, and strongly affect the compass. The rock is rather like the
"killas" of Cornish miners than our typical varieties of Lyman rock, so
that I have hesitated about separating it from the Lisbon group, without
further study. The same variety follows along the ridge to Connecticut
river, carrying the copper veins. Dr. Jackson states that the direction
of the strata of the copper mine in Bath is north-west and south-east,
which is at right angles to its usual course in the neighborhood. I have
noticed a south-east dip in the schists along the west border of the slates,
a mile east of the mine.

After reaching Lyman, we discover evidences of an anticlinal fold in

286 STRATIGRAPIIICAL GEOLOGY.

this group. The more eastern portion Hes to the east of Gardner moun-
tain, reaching to Parker hill on the east, and separated by a band of slate
from the more western development. Fig. 30 indicates the positions of
the strata along a section from the valley of Smith brook, in the south
part of Lyman, over Hart's mountain to the villages of Monroe and
Mclndoe's Falls on the Connecticut. At the east end, near a school-
house, the shales or slates prevail, covering up the supposed underlying
Lyman schists. These are inclined towards Gardner mountain. Next
the Lyman group makes it appearance, with two supposed outcrops of
the auriferous conglomerate. The range on what has been called the
Dow farm, but now Martin & Swett's, is believed to stop short at the
base of the hill, and to be folded. The eastern developments of the con-
glomerate and overlying dolomite may be present beneath the slates just
mentioned. All the strata exposed dip in the same direction with the
slates. Just west of the dolomite, which crosses Smith brook by Steery's
house, the slates reappear in strong force, with a very high south-easterly
dip, making, probably, a synclinal- originally with those by the school-
house before the upthrow of the Lyman group between. The auriferous
conglomerate reappears at Jacob Williams's house, where it has been
excavated for gold. A considerable alluvium west of Williams's makes
it uncertain whether there may not be a small development of the Lyman
group ; but in passing up the Smith brook one soon beholds prominent
ledges, with nearly vertical dip, of green schists of the Lisbon group.
These are as well characterized as any in the whole field, and remind
one forcibly of the typical Huronian localities in middle and northern
Vermont. Within the distance of a mile is the place for copper sqhists
to appear, for it is believed there is an anticlinal axis between Williams's
and Davis's houses, so that the copper rocks of Gardner mountain should
reappear. For the same reason, the accompanying synclinal ought to lie
along the valley of the Grafton mine. The south-easterly dips incline at
a much smaller angle on the eastern slope of Gardner mountain range
than in the valley near Williams's. At the old Grafton mine the dips
are 55'^ S. E. at the surface, and 45° lower down. The copper schists
arc well developed along this section. At the lead mine the strata dip
62° S. 80° E. It is possible that much of the cast side of the mountain
belongs to the Lyman group. The resemblances to this member are

GEOLOGY OF THE CONNECTICUT VALLEY DLSTRICT. 28/

greater in the sections — Figs. 29 and 31 — than on Fig. 30. At the very
top of the Gardner range, in the road, schists, which are greenish, dip
50'' south-easterly. Where the road turns northerly (now abandoned), the
dip changes to 75°-8o° N. 55° W. Down the very steep west side of
the range, the position is about the same. At the edge of Bath there is
a band of light-colored sandstone. The copper schists are believed to
occur near Hunt's mountain ; and there is probably a synclinal axis be-
tween this mountain and Bald ledge. At the latter locality the metallif-
erous schists have been worked at two openings on the top and west side.
These two lines dip in opposite directions, the first dipping 70°-75° S.
E., and the second 60° N. 40° W. This same north-westerly dip is now
continuous to the river. Near Monroe post-office the green, soft schists,
dolomite, and hard slates dip 75° N. 40° W. At Mclndoe's Falls the
ledges are of the same sort. Farther north-west, they are succeeded by
the calciferous mica schist, standing vertical, with the strike N. 60° E.
The union of these two formations is apparently one of unconformity,
unless there be a local disturbance.

Fig. 32 shows us the order of dips of the same rocks a little more than
two miles farther north of the last line described. It extends from the
Ammonoosuc river about a mile above Lisbon village to the top of Gard-
ner mountain, behind the Oro mine. At the eastern end of the section
are slates and conglomerates believed to belong to the Swift Water series.
The slates occur first, with a strike varying from N. 3 5 "-50° E., and the
dip north-westerly. This is the continuation of the slates cut by the
railroad just at the north edge of the village of Lisbon. The conglom-
erate associated appears on the hill half a mile back from the river. It
weathers whitish, and is known as conglomerate only after weathering.
The dark slates west of this rock hold bands of green schist. It is diffi-
cult to fix precisely the limits of the green schists by H. Aldrich's suc-
ceeding these slates. With our northern is a narrow band of white
schist and auriferous conglomerate dipping 80° N. The scattered ledges
of slate appearing here and there, just east of the conglomerate, may
have some connection with the regular Cambrian formation, which fol-
lows on the west, carrying gold. I have found in this immediate neigh-
borhood pieces of Helderberg limestone in such position as to make it
clear that a narrow band of it is in place just east of the conglomerate.

288 STRATIGRAPHICAL GEOLOGY.

The clay slates following rise up into a high wooded hill. The aver-
age dip of the whole formation is about 60° north-westerly, agreeing with
that shown on Fig. 28. The Lyman argillitic mica schist succeeds, dip-
ping at a steeper angle in the same general direction. A large bed of
quartz near the eastern edge has been opened, under the name of the
"New Hampshire Gold Mine." This band, though finely characteristic
of the Lyman series, is only about 1 100 feet wide upon the surface. Next
succeeds a width of Helderberg slates and limestones, estimated at eight
hundred feet. The exposures are well seen in the pasture south of the
road from the New Hampshire mine to that of the New England Mining
and Reduction Company. The Helderberg strata dip usually 75°-8o''
north-westerly. The fossils are minute broken crinoidal stems and cor-
als. Intercalated masses of rock are like the adjacent Lyman schists.
These easily-destroyed strata have probably been kept in place by an
enormous mass of the auriferous conglomerate, three hundred and eigh-
teen feet wide, which afforded protection on the north-west side. This
mass is much greater than ordinary, and must have accumulated through
a doubling by lateral pressure. The whole of it lies in the south angle
between the two roads meeting at the Reduction Works mine. The con-
glomerate runs N. 48° E., and stands vertical. On the west side of it
are green and white schists, with a dolomite bed, probably altogether
belonging to the Lyman group. The dip is high north-westerly east of
the road ; but at the mine, perhaps two hundred feet to the west, the dip
is 35°-7o' south-easterly. The band of conglomerate — a stone's throw
to the north-east — dips 70° S. 65° E.

There is at this point evidence of an extensive throw to the east. The
conglomerate would naturally continue directly from the edge of the Re-
duction Works mine to its development, a mile farther south ; but an
inspection of our map of the course of this rock shows that it has been
roughly broken apart, and pushed 11 60 feet farther east. Of course the
schists west of the conglomerate went with it. This great dislocation is
illustrated by the broken condition of the strata, both as seen in the
ledges, and as further developed by the working of the mine. The
change of the dip from that prevailing over the first mile of the section,
or that lying west of the clay slates, indicates here the existence of a
synclinal axis in the Lyman group. The dolomite and auriferous con-

Plate JkTIJI.

- Sections ACROSS the Ammonoosuc Gold Fielp.-

4,

Gardner >^

Fiq . S 2 . From Yet luttj'-s Tojid, Iiptian , to 'NortK IS/ionxoc

il

4 ^3 ui <

I. I S BO N^-^'G KO up • ^^'^^^ '^ ^^ ^^J '"'

IFig. 31. From ^Ammonoosac Tiiver alK)ve Lisbon Vi/lage to the OroAfine

y £0 •

Fici.50. J^na Smith BioohLxn-Tujitiiui^J^ioui. Sckoti liju8ejtoMclncloe''8 ^KJLLs

Fia.29. From Jkith licrwer Village to Connecticut River.
^ Vekticau Scale, 2000 Feet to an Incm. „____

"""""^ Horizontal - , about 1 Mi le - " '•

v»^v\<a-%^vsu

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 289

glomerate lie in the centre of the field, and are therefore the newer
members of the series.

I have not traversed the country between this mine and the road run-
ning north-east from Parker hill. The examination of the adjacent terri-
tory, however, indicates the character and position of the strata here.
We have, first, the argillitic Lyman schists, with south-easterly dip; then
a conglomerate composed of fragments of the same rock; and, lastly,
green-colored schists dipping 85° N. 40° W., indicating the presence of
an anticlinal axis before reaching the Parker Hill road and the repetition
of the clay slates.

This new slate range begins at Parker hill, and widens northerly, being
half a mile wide on the section line, and nearly two miles by the north
town line. This slate is usually inclined very steeply in a south-easterly
direction.

Passing on to the hill between this slate range and that next farther
west, we find a development of the Lisbon group between them. The
slate extends about a quarter of a mile w^est of the road at L, B. Hos-
kins's. The schists are considerably slaty, and there are narrow beds
of jasper intercalated with them. Certain cupreous veins cut across dol-
omitic strata, dipping 60° a little east of south. This set of cupreous
veins is probably continuous from the beds west of the Grafton mine,
represented upon Fig. 30. There must be an anticlinal in this area west
of Hoskins's, because the slates make their appearance, with the usual
high south-easterly dip, at the east base of Gardner mountain. The axis
may be an inverted one ; but we have no direct evidence from observa-
tion along this line. The clay slates occur, with the dip of about 60° S.
E., along the carriage-road at the east foot of the mountain. This may
be two hundred or three hundred feet thick, but sufficiently abundant to
indicate the presence of a newer rock, and consequently of a synclinal
fold in the strata. At the Oro mine the position of the strata is essen-
tially the same with that of the slates just mentioned. East of it there
is a band of quartzite ; and three hundred and seventy-five feet further
up the mountain is a band of dolomite. Much of the rock on the east
side of the mountain, near the copper belt, is soft and light-colored, and
therefore suggestive of the Lyman group.

Fig. 32 shows the position of the Huronian rocks, without so many of

VOL, II. ij

290 STRATIGRAPHICAL GEOLOGY.

the later series as in Fig. 31, and also crosses the mountain, extending
from Young's pond into the north part of Monroe. Just below the pond
there are outcrops of clay slate. To the south there are ledges dipping
75° S. 30° E., which, if protracted, would pass beneath the pond. Some
of them occupy the line of strike of Helderberg outcrops farther south.
The north-westerly dip of this band of slate begins about half a mile
below the outlet. Running beneath the west end of the pond is a fine
lot of Lyman conglomerate. At a mill the dip of it is 80° S. 60° E.
The west border of this series, at A. Knapp's, shows the dip S. 40° E.
The green schists succeed the white on the west, dipping 85° N. 40° W.
This is succeeded by the slates of the Dodge Pond vicinity, supposed to
dip south-easterly. After that comes in the westerly belt of Lisbon green
schist, agreeing in position with its description on the three previous fig-
ures. The slate comes out near the school, by A. L. Dike's, at the east
base of the range, indicating a fold. The copper schists occur in the
Alden Miner pasture lot, where excavations to a slight degree have been
made. They probably pass into the Swan and Garland property, in the
next lot adjacent upon the north. The dip of the cupriferous beds is 57°
S. 35° E., which extends to the top of the mountain.

Upon the Monroe side I have not seen the exposures for more than a
mile below the summit. I have reason to believe the rock there is the
Lisbon green schist; and that there are copper openings to correspond
with the structure reproduced in Fig. 30. Two openings for copper have
been seen about midway between the crest of the ridge and the river.
Way's copper beds dip 80° S. 35° E.; Mason's, 75° S. 35° E. No rocks
were observed west of these ledges near the road. The country falls off
to the west, and seems to be mostly covered by drift.

Fig. 33 exhibits the position and character of the strata near the south
line of Littleton, from S. Albee's house to the top of Blueberry mountain.
The older clay slates make up the principal mass of the mountain. On
top they dip 75° N. 20° W. A few rods north there is a local disloca-
tion, the dips of 80° N. 33° W. and 20° S. W. adjoining each other. The
slates are black, and contain crystals of pyrites. Immediately adjacent,
near a school-house, there is a coarse conglomerate. From the northern
slope of Blueberry hill to Mulliken brook the soil is fertile, and covers
most of the ledges. Near the stream there is a mixture of Helderberg

GEOLOGY OF THE CONNECTICUT VALLEY DLSTRICT. 29I

coralline limestones and easily-decomposing slates, standing upon their
edges. Associated with them, towards the coarse conglomerate, are
loosely-coherent sandstones resembling similar fossiliferous rocks in ad-
joining slates. On the west of the Helderberg there follows a half mile
width of vertical strata of the Lyman group, including the "Indian rock"
near the house of G. D. Shute. Between the top of the hill west and
Partridge pond, the Lisbon group succeeds. About the pond we find
the nearly-vertical slates, the northern prolongation of the Parker Hill
range, and also the Lyman group conglomerate. The Lisbon range
bordering this on the west again makes its appearance, with a greater
breadth ; and the copper is better developed than at some of the locali-
ties farther south, it having been worked slightly at the White Mountain
or Quint mine.

The v/estern limits of this Oaint range are not well known. Near the
house of I\Ir. Little (E. Parker's) there are cupreous schists; and the clay
slate range must pass very near this site, since it occurs to the south, as
before mentioned, near the copper, and to the north quite extensively
about the West Littleton post-of^ce. In climbing the hill west of Little's
house, to see the principal copper mass, I do not recall this rock ; but my
attention had not been turned to it at that time, and it might have been
passed unheeded. At this opening the dip of the strata is 60° S. 70° E.,
and the metalliferous schists are very abundant. Their course has been
followed a considerable distance in both directions, it being the main
vein of the Gardner Mountain deposit. From this opening across to the
Albee mine it cannot be more than half a mile. The strata with the lat-
ter vein dip 65° S. 40'' E., and nearer the house 70° S. 45° E. There is
said to be another bed of copper one hundred and twenty-five feet east of
the Albee mine, or nearer the Little mine. A comparison of these seve-
ral figures with each other suggests that the Albee veins would probably
coincide better with those nearest the ridge in Figs. 30 and 32, than with
those worked in the south part of Monroe, and those opened by Way
and Mason farther north. The mountain has diminished greatly in alti-
tude between Little's and Albee's, and falls gradually from those places to
Connecticut river; and the strata between the two sets of cupreous rocks
do not make an obvious anticlinal with each other, as is the case in Fig.
30. There would seem to be a growing tendency to an overturn in

292 STRATIGRAPHICAL GEOLOGY.

passing from Fig. 30 to Fig. 32, which has become completed in Fig. 33,
the dip upon both sides of the mountain being essentially at the same
angle.

There is little to add concerning the occurrence of the Lisbon group
in Monroe. Our observations have been scanty ; and, so far as mapped,
the green schists appear to occupy the whole township. At P. P. Ma-
son's the dip is 60° S. 48° E. Somewhat below the middle of the town,
at J. Nelson's, there is a broad band of pyritiferous granular quartz, dip-
ping 80° S. 70° E. A fourth of a mile south, near G. Lang's, there are
green schists, vertical, with the strike N. 5° E. The general character
of the Monroe schists is sandy and micaceous, without much of the chlo-
ritic aspect. South of Lang's the strike is N. 15° E. At the lower Bel-
den opening the dip is 60° N. 40° W.; at the upper it is from 70° to 75°
south-easterly, — thus making a very distinct anticlinal. There is a grad-
ual slope to Connecticut river from the summit of the ridge through
the upper three fourths of the township ; the other part is considerably
steeper.

The western half of Littleton consists mostly of the Lisbon group.
This development is characterized by the predominance of chloritic and
green schists ; and the cupreous layers are scarce. The Gardner Moun-
tain and the Quint Mine ranges pass out of the state into Waterford, Vt.;
while the Parker Hill range occupies a large area adjacent to Connecticut
river. The Lisbon areas terminate mostly in Littleton, save one which
passes through the south-west corner of Dalton on its way into Vermont.
Section IX passes through the most important portion of these Huronian
bands in Littleton.

In general, the rocks from J. Bowman's, near Lower Waterford bridge,
to W. Redwood's, a mile and three quarters east of the upper bridge, are
chloritic, usually perpendicular, with a north-east strike. At Mulliken's
saw-mill the green schists are traversed by a trap dyke, and some of the
rock is conglomeratic, of the Lyman group. The rocks are similar on a
back road from the saw-mill to near the slate quarry. Near the town-
house is the boundary between the grayish-green schists and the mix-
ture of chlorite and feldspar. Of the former, there may be a width of
two miles east of the true chloritic rock. The same outcrops at inter-
vals between the town-house and the Wheeler Hill cemetery, where it is

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 293

replaced as before by the chlorite schist. Bands of slate holding large
nodules of quartzite occur east of Wheeler's. On Wheeler hill — west
side — are hydro-micaceous schists. Near the summit the character is
more argillaceous, and the rock carries a little copper. Some of the
bands have a chocolate color. The direct road to Dalton from North
Littleton is entirely covered by drift ; and the same is true of the river
road. The road branching off from the main road, on the south side
of Cow brook, gives us a glimpse at green schists, at R. Moore's, with
the strike N. 50° E. The same rocks occur abundantly farther east on
the north side of the Palmer hill, near a sharp angle in it. On the north
side of Morse hill, between L. B. Towne's and the slate quarry of R.
Smith, there are green schists, with strike seeming to point to R.
Moore's. The results of further examinations in Littleton and Lisbon
will appear under the head of the Lyman group, further on.

A trip across Waterford, in 1858, may furnish a few hints concerning
these rocks. At the lower village the hydro-mica schists, minutely con-
torted, dip 65° south-easterly. Next is a higher-dipping series of 80° in
the same direction, with a multitude of the diabasic porphyritic boulders
of the rock yielding Stromatopora, probably in situ. This is followed
by soft schists, 80° south-easterly. The west border of the formation
stands 85° south-easterly, made of harsh grits and breccias. It is suc-
ceeded at the Passumpsic river by clay slate.

Lyman Group. Early in the history of our explorations it was found
needful to separate the "white schists" from the green, or the Lyman
from the Lisbon group. When unweathered, the rock usually assumes a
drab color, often with an olive-greenish tint, but always, after exposure,
becoming grayish-white, somewhat resembling feldspathic rocks at a dis-
tance. Somewhat argillaceous and shaly layers, together with dolomitic
beds, are interspersed with it, capped by the auriferous conglomerate.
According to Mr. Hawes's determinations, this rock is an argillitic mica
schist, intermediate in character between mica schist and clay slate, very
like the German Wcrthonschicfer, or the first starting away from clay
schists. Some of the varieties exhibit a little mica ; more usually, how-
ever, the plates are wanting, and the texture reminds one of flint.

The principal range of this rock commences in the north part of Bath,
crosses Smith brook in Lyman, and passes through Lyman into Littleton.

294 STRATIGRAPHICAL GEOLOGY.

Many of the details of its distribution and stratigraphical relations have
been touched upon in the descriptions of Figs. 29-33, Plate XIII.

By reference to the map exhibiting the south end of the auriferous
conglomerate in Bath, it appears that the Lyman schists are enclosed by
it, and the conglomerate is encompassed by clay slate, while the slates
apparently dip beneath the other rocks. This does not represent the
true mutual relations of these formations, as the slates overlie the others.
A careful examination of the dips from the south end of the conglomer-
ate to the neighborhood of the house of J. Clough (county map), proves
the existence of singular disturbances, both dislocations and overturns.
The normal dip of the slate upon the east side of the conglomerate in
Bath is 30°-40° N. 42° W. The strike is the same upon the west side
and to the south ; but the dip varies, as will be described further along,
in accordance with the synclinal disposition of the mass. In the road a
little west of the brick house (M. L. Sanborn, of county map), the dip is
to the north. Quite near to the conglomerate, upon the west side, the
dip is N. 33° E., and N. 18° E. The slate and conglomerate are sepa-
rated by a few feet thickness of the argillitic mica schist and the common
shelly layers of the Lyman group. Three hundred feet west of the con-
glomerate the slate dips N. 72° W., or more nearly its proper position.
The usual presence of the few layers of Lyman rocks with the conglom-
erate, not merely here, but very commonly where the conglomerate lies
in close proximity to the slate, indicates the proper associations of the
former rock, and that the latter has been crowded over it by lateral
pressure.

Near the south end of the conglomerate upon the hill there is another
illustration of this conclusion. Two masses of conglomerate run parallel
to each other a few rods apart, both uniformly having a strike a little east
of north. Between them lies an abundance of the slate, with the uniform
north-westerly dip belonging to it, thus unconformably overlying the con-
glomerate.

The action of the lateral pressure is further exhibited a few rods north-
easterly from Clough's house. A hummock of the Lyman dolomitic
and quartzose rocks rises out of the slate; or, perhaps it should be said,
rather, the rocks associated with the conglomerate extend westward more
than is usual, and consequently the slate has been displaced. A portion

■ GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 295

has been entirely removed by the drift, and that remaining is forced to
dip to the north. About a stone's throw distant to the west, the normal
dip to the north-west appears again. If the slate dipped underneath the
Lyman beds, the latter would have been eroded, instead, and made to
disappear. This and other similar facts indicate that the Lyman rocks
in this field constitute a hard, irregular floor, upon which the slates were
placed by deposition. When lateral pressure was exerted upon this ter-
ritory, the floor would be disposed more unevenly than at first, and the
upper and more yielding rock be forced to accommodate itself to it.
Hence the slates would be bent, broken, and thus put into proper con-
dition to be removed largely by later erosive agencies, permitting us to
see the natural limits of their distribution by imagining the scattered
remnants left once joined together.

The main range of Lyman schists in Bath widens in proceeding north-
erly. At J. Hastings's it dips north-westerly, as usual. The most inter-
esting feature connected with it is the branching to the east of a mass of
both the white and greenish schists, so connected together as to make it
difficult to decide whether both the Lisbon and Lyman groups may not
be present. The road from the school-house, about a mile above the
mouth of Smith brook, passing over the hill by J. Dow's, E. McAdair's,
etc., crosses over a band of green schists about half a mile wide. If we
pass towards the conglomerate from where these exposures appear, we
find them cut off by a shelly slate, and discover beautiful examples of
contorted strata. Hence a dislocation is evident, whose position is ap-
parent upon the map, having a north-westerly course. The green schists
occupy the middle portion of this area, where they cross into Lyman.
The whole area is about three thousand feet wide on the town line, some
four hundred feet on the west, and fifteen hundred feet on the east, being
of the whiter variety. The green schists run north-easterly about three
thousand feet into Lyman, and their place is taken by the whiter layers
further on. But there are green schists in a band five hundred feet wide,
tapering to a point, reaching from the school-house to a ledge past the
Bedell mine. The latter range is covered by clay slate.

Reference should now be made to the numerous observations recorded
upon the special map of four square miles' extent in the south corner of
Lyman, surveyed with great pains for the purpose of elucidating the

296 STRATIGRAPHICAL GEOLOGY.

stratigraphical structure of the gold field. It was drawn upon the scale
of five hundred feet to the inch, and reduced by photography to its pres-
ent dimensions. Stakes were set at the corners of every block of five
hundred feet, the positions being determined by theodolite and chaining.
Their places are indicated by dots upon the map, together with refer-
ences to town lines and other topographical features outside of the four
square miles measured. For convenience of reference, the letters A, B,
C, etc., designate the positions near the east Hne of the town next Lis-
bon ; while upon the line next Bath figures express the several stakes in
order, beginning at the south-east corner of the town. For example,
C — 13 denotes the stake two hundred feet northerly from the Bath line,
and six thousand five hundred feet westerly from the east line of refer-
ence, which nearly coincides with the town line between Lyman and
Lisbon. Figures express the catalogue numbers of the specimens ob-
tained, and are placed as exactly as possible over the localities whence
they came. Arrows show the dip of the strata ; while more precise in-
formation concerning the exact angles follows in the text.

We have the following details respecting the position of the green strata in the
area just mentioned, entering Lyman from Bath :

150-152— dip 85° N. 42° W. 156— dip 50° N. 22° W.

153— dip 62° N. 40° W. 289, 290— dip 55° N. 32° W.

154— dip 50° N. 42° W. 185-187— dip 70° N. 32° W.

The following are the positions of the whiter schists connected with the foregoing,
extending as far north as the line J, but not embracing any that lie east of the green
schists, since the latter will be described as a separate range :

293, 294 — dip N. 32° W. 296 — dip 45° N. 32° E.

290— dip 55° N. 32° W. 288— dip 85° N. 32° W.

289— dip 70° N. 42° W. 287— dip vertical, strike N. 68° E.

From the range of green schists between the school-house and Bedell's, we have —

161, 162— dip 60° N. 23° E. Near H— 19, Bedell's mine, 80° N. 22° W.

Where the main range enters Lyman the rock is shaly, and is not always easy to
distinguish from the clay slates. Upon the hill east from Smith brook the rock is
typical of the group. The observations are quite numerous.

At B— 21, vertical, strike N. 48° E. At H— 15, 85° N. 27° W.

At G — 19, vertical, strike K. 58° E. North end of a conglomerate fold near

At I— 19, vertical. F— 15. 80° N. 42° W.

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GEOLOGY OF '^IIE CONNECTICUT VALLEY DISTRICT.

297

Between H and I— 14, 72° N. 8° E.
Near J — 14, a patch of green schist stands

vertical with strike N. 72° W,
NearJ— ii,dip6o°N. 8° E.
West of I— 10, dip 55° N. 2° W.
Near I— 10, dip N. 8° E.
At J— 8, vertical strike N. 48° E.
At K— 9, dip 55° N. 23° W.
Between J and K— 10, dip 40° N. 33° E.
Between J and K— 12, dip N. 12° W.
South-east of L— 11, dip 70° N. 12° W.
Between K and L— 10, dip 42° N. 12° W.
Bet^veen K and L— 8, dip 65° N. 32° W.
At M— 9, dip 42° N. 13° E.
Between M and N— 10, 50° N. 12° W.
North of M— II, 58° N. 12° W.
Near N — 12, dip 60° N. 12° W.
Near N— 13, dip 65° N. 8° E.
At M— 13, dip N. 12° W.
At M— 14, dip N. 8° E.
Between M and N — 14, dip 72° N. 12° W.
Large quartz bed at O — 6, dip N. 42° W.
At 0—5, dip N. 65° W. 60°.
Near P— 6, dip 30° N. 12° W.
At P— ID, dip 80° N. 32° W.
At P— II, dip 75° N. 22° W.
At O— 10, dip 50° N. 12° W.
Between N and O— 10, dip 64° N. 22° W.
Between O — 11 and 12, dip 40° N. 8° E.
Between O— 12 and P — 11, dip 48° N.

32° W.
Between N and O — 13, dip 40° N. 12° W.
At O— 13, dip 62° N. 12° W.
At P— 13, dip 70° N. 670 W.
Between O and P — 14, dip 80° N. 32°

W.
At P— 14, dip 70° N. 12° W.
200 feet south of last, dip 62° N. 12° W.
Near P— 18, dip 70° N. 22° W.
Between Q and R— 14, dip 70° N, 12° W.
AtR— 14, dip 82° N. 12° W.
VOL. IL 38

About Q— II, dip 85° N. 12° W.

200 feet east of Q — 11, dip 55° N. 22" W.

AtQ— 9, dip 68° N. 12° W.

North-west of Q— 8, dip 62° N. 12° W.

North-east of Q— 8, dip 88° N. 12° W.

Near R— 7, dip 50° N. 18° E.

At R — 8 (argillaceous) vertical, strike N.

78° E.
At R— 7, dip 66° N, 18° E.
300 feet east of R— 7, dip 74° N. 18° E.,

adjacent to clay slate.
250 feet east of S— 7, dip 70° N. 52° W.
At S— 8, dip 70° N. 32° W.
Between T — 7 and 8, a curve, the dip grad-
ually passing from 65° N. 28° E., to

N. 42° W. 67°.
250 feet east of T— 7, dip 72° N. 12° W.
75 feet north of T— 7, dip N. 42° E.
North-east of U— 6, dip 85° N. 32° W.,

adjacent to clay slate.
200 feet south of V— 7, dip 65° N. 32° W.
300 feet north of U — 7, dip 73° N. 22° W.
250 feet south-west of V — 8, dip 84° N.

12° W.
300 feet north of U— 8, dip 88° N. 12° W.
At U— 8, dip N. 12° W.
North of S— 9, vertical, strike N. 48° E.
South of T— 10, dip 70° N. 38° E.
East of T— 10, dip 75° N. 42° W.
Between T— 9 and T— 10, dip 75° N. 42°

W.
300 feet north of R — 10, dip 90° N. 42°

W. (argillaceous).
Near S— 10, dip 62° N. 52° W.
200 feet north of last, dip 62° N. 12° W.
300 feet east of R — 11, green schist, dip

76° N. 12° W.
Near V — 11, green schist, dip 88° N. 12°

W.
About R— 14, dip 82° N. 12° W.

298 STRATIGRAPHICAL GEOLOGY.

The following occur north of the conglomerate towards Parker hill :

Between U and V— 16, dip 75° S. 22° E. About V— 17, dip 80° south-easterly.
Near V— 16, dip 85° south-easterly. About V— 19, dip 88° N. 32° W.

These observations establish the fact of a prevalence of a dip in the
direction N. 12° — 25° W. over the hill region occupied by the main range
of Lyman rock in the south part of the town. The variations to the
east may be due to local bendings and dislocations, explained partly by
the presence of newer strata. Along a line crossing the strata from J — 8
to P — 14 we have the following angles of inclination : 75°, 55°, 42° on top
of the ridge, 70°, 60°, 65°, 40° and 80°. From these observations alone
we are not warranted in concluding how many folds there may be. From
general considerations there is thought to exist at least one synclinal
over this main range.

The occurrence of narrow bands of dark carbonaceous argillaceous
schists over this area, might, if properly worked out, illustrate the fold-
ings. Like much of the argillitic mica schist, this rock splits up into
long, narrow lenticular pieces, many of them being about the size of
artificial scythe stones. There seems to be a band of this rock traceable
from the Parker and Young lot across to the Dow conglomerate, F — 16,
and a longer one perhaps from near Jacob Williams's, G — 19 to T — 9; or,
rather, in the north-east part of the map, there are three bands of this
slate, viz., from R — 8 westerly, T — 9 to R — 10, and quite near the twisted
conglomerate, not far from Horace Aldrich's house, running towards
Q and R — 14.

There are also large beds of white quartz, sometimes metalliferous,
which probably have a fixed stratigraphical horizon in this area. The
most marked is that along the eastern border, starting on the north at
the New Hampshire Gold company's mine north of the map area, crop-
ping out west of the Dodge mine, near the western line of J. Titus, or
near O — 6, between M — 5 and 6, at J — 12. These and other outcrops
are carefully laid down upon the map, as they may have economical
importance.

A feature of greater stratigraphical importance than the quartz or
slate is the dolomite. This may be readily distinguished by its reddish
iron color, arising from decomposition, and it is unusually persistent in
distribution. It seems to follow the conglomerate very closely in all its

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 299

curved and fragmentary way, the best known localities being upon its
north-westerly side. Of these, we have No. 196, near F — 15, dipping 80°
N. 42° W., away from and apparently over the conglomerate. No. 195,
though disconnected with the range, probably belongs to it. A similar
layer is connected with the larger development of conglomerate about F
and G — 16, and it seems to cross Smith brook near Steery's house, north
of E — 18, and to continue at D — 19. Between D and E — 20, on the
south-west side of the conglomerate, is another exposure of the dolomite.
No. 202 from Q — 17 is quite interesting. It is more like a limestone
than is usual in Lyman, and it makes a right angle in its course. The
north-south course lies at the south-west end of a conglomerate exposure,
and the bend to the west is connected with the throws of the latter rock,
not fully understood. The dolomitic band is about twenty-five feet wide.
There is said to be a considerable dolomite between Q — 17 and J. Wil-
liams's, nearly along the line of the conglomerate. Next, there are dolo-
mite layers at T — 14 and 15, Where the conglomerate has been so
terribly thrown about in the neighborhood of Aldrich's, the dolomitic
outcrops are abundant, and may be seen on the map. The small con-
glomerate mass at U — 9 is accompanied by dolomite, — Nos. 210-212.

The dolomitic masses not connected obviously with conglomerate may
show where fragmentary bits of it are to be found, as at No. 206, near
T — II, No. 209, near S — 8, Nos. 207-208, near R — 11. Those south of
P — 14, and near L — 8, are not so clearly connected. Those from N — 21
and D — 21 may be associated with the Lisbon group. In the eastern
Lyman range we find Nos. 191, 192, and ledges near A — 5, close by con-
glomerates, and No. 193 by H — 2, somewhat isolated. No. 194 is also
in the neighborhood of conglomerate. We have also several observations
showing the proximity of the dolomitic band to the conglomerate in Bath.

The following are a few positions of this dolomite band not elsewhere recorded :

193, near H— 2, 75° northerly. 210, near V — 7, dip 66° N. 52° W.

202, near Q— 17, vertical, strike N. 72° W. 212, near U and V— 7 and 8, dip 80° N.

205. U— II, vertical, strike N. 48° E. 42° W.

206, near T— 11, dip 68 N. 12° W. 200 feet southof P— 14, dip 62° N. I2°W.
209, near S— 8, dip 85° N. 12° W.

The composition of much of the Lyman schist is indicated by speci-
mens from between T — 8 and 9 and P — 10. It is a conglomerate made

300 STRATIGRAPHICAL GEOLOGY.

of long, flattened elliptical pebbles of sandstone, having the shape very
nearly of whetstones used for sharpening scythes. The original rock has
essentially the same mineral character with the derived strata. Usually
the process of metamorphism, or rock-development, has been carried on
so far that the grains and coarser pebbles have disappeared, being merged
into the homogeneous argillitic mica schist. In a multitude of cases a
practised eye will recognize the outlines of the pebbles in these ledges,
which a stranger would not readily discover. No. 335 is an example of
another variety of conglomerate, with small rounded pebbles of quartz
and longer patches of a white, soft rock, the whole abundantly cemented
by an argillaceous paste. This variety is not common. Whether any of
these conglomerates may be the equivalent of the auriferous variety soon
to be described, becomes a perplexing question after passing the known
bounds of the latter.

The Lyman group may be distinctly followed beyond the limits of the
special map through Lyman into Littleton. Much of it is covered by
later formations. The eastern border passes uninterruptedly to Young's
pond. The dip is at first about 80° north-westerly, but on the south side
of the pond it is 75° S. 30° E. Figs. 31 and 32 may illustrate the course
of the Lyman group in this region. The two gold mines represented in
Fig. 3 1 are on opposite sides of a synclinal. At Young's pond the strata
are monoclinal, most likely comprising only the western part of the for-
mation, the eastern being covered unconformably by the clay slate, in
agreement with the condition of things described upon page 283. Facts
about the Lyman group, on Fig. 31, have been presented upon pages 288
and 289.

On taking the road to Young's pond from the Reduction Company's
mine, we first pass over supposed Helderberg slates. Turning on the
first road to the left, near J. E. Barber's, we find first at his house a ledge
of green schists. Behind the house the rock is the well known "scythe-
stone conglomerate" of the Lyman group, dipping south-east. This con-
tinues to 400 feet beyond H. Knapp's, where we find the normal argillitic
mica schist standing upon edge. The Lisbon group makes its appear-
ance by J. M. Smith's, on the turn to Young's pond, having the dip 85°
N. 42° W. At A. Knapp's, half way to the pond, the argillitic mica
schist dips S. 42° E. Between here and the pond there is a large de-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 3OI

velopraent of the peculiar conglomerate seen back of Barber s, in numer-
ous embossed ledges. At the mill above the pond this conglomerate
dips 80° S. 62° E.

North of Young's pond the boundary between the slates and schist is
very irregular, on account of the uneven erosion of the former resting
like a blanket upon the latter. A spur of schist runs northerly from the
pond into Mormon hill, all the ledges adjacent to this shore being the
same. The road to H. Scales's house passes over schist nearly to G.
Presby's ; then it crosses the serrated boundary between the slates and
argillitic conglomerate. There are at least five serratures or projections
of the slate over the conglomerate, which may be seen best upon the
map. On the hill west of Scales's the schistose conglomerate dips 80°
N. 62° W. The slates dip north-westerly, in some cases being inverted.

The schists have not been followed across the west flank of Mormon
hill, but are supposed to be continuous with the ledges seen in the stream
east of G. D. Shute's, in the south part of Littleton, dipping 80° N. 42^^
W., and delineated upon Fig. 33. They are here flanked south-easterly
by Helderberg flags, and north-westerly by the Lisbon group. They
continue north-easterly from Shute's across the township, widening north-
erly, and crowding the Lisbon group into Vermont north of Littleton.
The next road crossing them is that running directly from the slate
quarry to Upper Waterford bridge. The rock is about vertical, and lies
between the houses of D. Robbins and A. Eastman — half a mile. Next
it crosses the roads from Littleton to this same bridge and to Lancaster.
It occupies much of Wheeler hill, and perhaps it should be made to cover
all the ground from Palmer hill to the Helderberg on Burnham hill. The
dips on this last route are given in the first figure descriptive of the Hel-
derberg rocks. On the south side of these hills, west of E. Farr's, green-
ish schists occur, dipping 78° N. 40° W. At P. S. Hatch's, north of the
limestone, the white rocks dip 40° S. 42° E. On the road between
Mann's hill and Mt. Misery this rock dips N. 12° W. and N. 32° W., near
J. W. Dudley's. On the north side of the road excavations have been
made in this for gold. The rock is completely filled with pyrites, so that
small specimens even cannot be obtained free from the sulphuret. Mid-
way between the Mt. Misery road and the one along Cow brook, the
dip is from 5o°-7o° S. 6° W. Farther west, at M. Fisk's, in perhaps an

302 STRATIGRAPHICAL GEOLOGY.

isolated band of this rock, tlie dip is N. 50° W. 78°. An argillaceous
schist extends from here three fourths the distance up Morse hill, where
the argillitic white schist dips 56° N. 42° W. On the south side of
Morse hill there are alternate bands of these two rocks, dipping 6o°-8o°

N. 22°-32° W.

There is a curious conglomerate west of Rev. C. Coming's, in North
Lyman, lying adjacent to the Lyman group, and supposed formerly to
constitute a part of it. It resembles a mass of common drift, because
the pebbles are so numerous and miscellaneously arranged. They con-
sist of both the white and green schists, and dip S. 52° E. The pebbles
are mostly of large size, one measuring two feet long and five inches wide.
On the top of Mormon hill, nearly two miles north-east of this exposure,
I found a very coarse conglomerate, with the strike N. 58° E., lying on
the north-west side of clay slates dipping N. 47° W. It is probable that
these two exposures belong to the same formation, which runs athwart the
Lyman group, and may possibly join a very coarse supposed Helderberg
conglomerate in Littleton, to be described presently. Till the very latest
moment I had regarded these heterogeneous mixtures as a part of the
Lyman group. There is, however, another interesting exposure of the
supposed conglomerate at D, Stickney's, to the north-west of the range
just mentioned. The strata are greatly contorted, the seams being filled
with reticulated veins of white quartz, such as always occur at the bend-
ing of a formation in this part of the country. The dip seems to be
north-westerly usually, though some incline N. 8° E.

A trip to Mt. Littleton, in 1876, adds a few items of interest. After
passing the slate quarry, there is, first, the diabase range from Fitch hill,
then the Lyman schists, by Robbins's and Eastman's, then a broad ex-
panse of chloritic schists extending along Mulliken's brook from East-
man's, and connecting southerly with the Lisbon group near Partridge
pond. Where the road from Mulliken's brook joins the Partridge Pond
road, I found a coarse Lyman conglomerate, perhaps the continuation of
that at D. Stickney's, dipping south-westerly. The same recurred north
of the pond, at G. D. Lewis's, with a south-easterly dip, thus making a
synclinal, holding some slates near the water. Either this or the normal
Lyman rocks crop out farther south, especially above the mills at Mul-
liken's, near the Connecticut river, standing vertically. It appears, there-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 303

fore, that there is a range of Lyman rock from Partridge pond to the
Connecticut near the Upper Waterford bridge.

There is an eastern range of the Lyman group similar, as respects
mineral composition, to that just described, requiring notice. It adjoins
the green schists extending into Lyman from Bath, thought to be subordi-
nate to the white schists. They are 2500 feet wide on the Lyman line,
including three narrow conglomerate belts. The following are such posi-
tions of the strata as have been determined in this area :

283, dip 80° N. 82° W. 400 feet east of B— 3, and near road, dip

280, dip 64° S. 57° E. 67 S. 57° E.

At B — 5, dip N. 57° W. Close by conglomerate, 300 feet east of

Half way to C — 5 the dip changes to 65° C — 4, dip 70° S. 57° E.

S. 57° E., thus indicating the presence Dip beneath the conglomerate, on the

of an anticlinal. other side, in a similar manner.
Near C — 3, vertical, strike north-easterly.

Near the south end of the conglomerate, between E — 5 and F — 4, are disturbances.
The schists, six feet distant from the conglomerate dipping N. 42° W. 80°, and sepa-
rated probably by a fault, are inclined 70*^ south.

At F— 3, dip N. 22° W. Between L and M— o, dip 75° N. 23° W.

Same, 100 feet west of F — 2. Town line east of O — o, dip 55° N. 17° W.

Between G — 2 and 3, dip irregularly N. Anticlinal about M — i, dipping 55° N. 2°

32° W. W. and 65° S. 47° E.

At H — 3, dip 65° N. 22° W. 100 feet north of N — o, dip 75° northerly.

East of J— 2. dip 60° N. 12° W.

There is dolomite near H — 2 dipping 75° northerly ; between E — 5 and 6, dipping
70° S. 57° E., extending east of the conglomerate from Bath line 1000 feet between
lines 3 and 4, dipping 85° N. 62° W., and probably on the west side of the same range.
This range also contains argillaceous schists and beds or veins of quartz similar to
those described as connected with the larger area.

The clay slate covers up most of this range in Lisbon, as has been
explained upon page 283. There is also a fault north of Jason Titus's
house, which aids in accounting for the disappearance of the Lyman
group. Beyond the sandy plain it may be followed, accompanying the
conglomerate as far as the saw-mill upon Mill brook, but it is quite nar-
row.

Auriferous Conglomerate. The last of the Huronian members to be
described is usually a quartz conglomerate, with pebbles half an inch in

304 STRATIGRAPHICAL GEOLOGY.

diameter, from ten to a hundred feet in width. Owing to its hardness it
has resisted disintegration better than the adjacent schists, and hence its
outcrops are usually very conspicuous. It is this feature which led me
to study its distribution with great care, so that it might be possible to
obtain a clue to the stratigraphical structure of the whole field. The
knowledge of the curves, breaks, and throws of this member illustrates
finely the difficulties in the way of elucidating completely the intricacies
of New Hampshire geology. The adjacent schists must be broken and
curved precisely like the conglomerate. Upon the map I have deline-
ated only the outcrops, without attempting to connect them together.
Doubtless in many cases there can be no direct connection, the forma-
tion having been broken into pieces which became widely separated from
one another. In other cases I have not yet been able to satisfy myself
how the connecting lines should be drawn.

Besides quartz I find occasionally pebbles of jasper, chlorite, and both
the green and white schists. I do not recall examples of pebbles much
more than two inches in diameter. The cementing material is analogous
to the composition of the adjacent schistose rocks. There may be a few
cases of the distortion of the component pebbles by pressure, but they
are mostly roundish or elliptical. Metamorphism has operated upon this
conglomerate, so that the pebbles often seem to run into the cement by
imperceptible gradations; and a piece freshly broken from a few feet
depth does not readily display the fragmentary structure brought out
upon the surface by weathering. I have occasionally seen the pebbles
cut through by the jointed structure traversing the ledge. It is very
common to see small reticulated veins of quartz traversing these ledges,
especially in the neighborhood of a sharp bend or break in the continuity
of the formation. Indeed, so intimate is the connection between these
two phenomena, that, whenever I discover the numerous white veins, I
conclude immediately this must be in the vicinity of a bend, and never
fail to observe other tokens of its presence. In limestones the corre-
sponding feature is seen in the presence of similarly disposed veins of
white calcite. The designation auriferous came to be applied to this
rock by way of contrast with other fragmentary accumulations. Several
openings had been made in this member for the purpose of mining gold ;
and the mass has yielded from forty cents to two dollars per ton upon

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 305

assay. Hence the name auriferous, as any one of its exposures is likely
to yield a trace of the precious metal. At some of the openings pyrrho-
tite occurs in considerable quantity, and, in fact, it is apt to occur in any
ledge of it. It is not therefore certain whether the gold discovered comes
from the pyrites or the quartz ; and if from the latter, whether it consti-
tutes a part of the original conglomerate, forming pebbles like those of
quartz, or whether it entered with the siliceous infiltrating matter. The
constituent fragments were derived from the adjacent auriferous strata,
so that the presence of gold in the pebbly condition may be looked for,
though the whole of it has not been originated in that way. This con-
glomerate is disposed in two groups, corresponding to the main and east-
ern subordinate ranges of the Lyman group. Each one is double, or
arranged into two parallel lines, as if repeated by undulations in the
strata. I will describe the more western ranges first.

It is singular that this formation should commence so abruptly, and
exhibit no traces of its existence to the north of Young's pond ; — yet the
enclosing material is traceable with difficulty beyond this point, because
it is covered by newer slates, hence the same explanation may account
for the concealment of the conglomerate.

North of the mine of the New England Mining and Reduction Company is an out-
crop of the conglomerate 1600 feet long, parallel with the road and a short distance west
from it. At the south end it dips 70° S. 67° E. The course of the ledge is N. 23° E.,
and it may be fifty feet wide. The continuity is broken at the south end of this mass,
and, by proceeding S. 30° E. 1160 feet, it is found again about a hundred feet to the
south of D. Knapp's house. Proceeding S. 50° W. for about 500 feet, we find an
enormous expanse of this rock, attaining 335 feet in its greatest width. The strata
are nearly vertical, about 80° south-easterly, rather steeper than appears upon Fig. 31.
This part of the formation is flanked on the north-west by green hydro-mica schist,
and by Helderberg slates upon the south-east. On account of its superior hardness
it occupies the crest of a hill, the highest in the immediate vicinity. It would seem
as if this mass must be folded up at least once, in order to account for its great thick-
ness.

The next section of this range exhibits three bends, not including the right angle
made by its starting opposite the very thick portion of the mass just described. We
have first a bend of about 70° easterly, then of 150° to the west, and a third of over
120° to the east again. The length of the range, after leaving the very thick mass by a
right angle, is about 140 feet. It then proceeds S. 35° W. after the 70° bend, for about
500 feet. Next, for about 700 feet, after bending 150°, it has the course of S. 70° W.
VOL. II. 39

306 STRATIGRAPHICAL GEOLOGY.

After bending 120° it runs S. 30° E., about 480 feet, when it sinks beneath the allu-
vium. The valley of a brook intervenes next. As it then crops out, having the same
direction for more than 500 feet, after a short concealment, it must be continuous for
the whole distance of a third of a mile. The next bend makes an angle of 110°, and
the course is to the west for an eighth of a mile. At the next angle there is a subordi-
nate bend, and the ledge courses for an eighth of a mile about S. 30° E. to the house
of Horace Aldrich, situated upon the road from Lisbon to Parker hill, and at the place
where a road branches to Young's pond, passing by the New England Company's mine.
The width of the conglomerate, after the first quadrangular bend to Aldrich's, is from
thirty to sixty feet. The delineation of the portion just described is not quite so accu-
rate as that which follows, and I shall now rely more upon reference to the map in
speaking of its continuation.

On the south-west side of the road from Aldrich's, upon an eminence and enclosed
within an area of 500 feet square, is a series of twists too intricate to be described
minutely. Upon looking at this and other similar bendings, one feels as if the original
formation was like an elastic string in a state of strong tension, when it broke, and
both ends suddenly recoiled and assumed a doubled-up appearance. The more south-
ern part of this twist is a loop with the sides parallel to each other, the course being
about north and south. The width of this rock in the road is sixty feet ; the other
extremity is about half as thick. The rocks bordering the curves conform to them,
consisting of dolomites and slates. The probable continuation of the south end of the
loop is to be found 550 feet distant, 275 feet east of V — 10, it being the end of a mass
275 feet long and twenty wide, running about S. 35° W.

Next, there are numerous outcroi^s of conglomerate, averaging twelve or fifteen feet
in width, in all respects similar to the wider bands, but when joined together continu-
ously they more than fill out the gap between the exposures of the larger ledges. For
the present, I think they belong to the same band continued southerly, or to what was
originally more shallow water in the ancient sea where the rock grew. The first expo-
sure at V — II would connect well with those in the 500-feet square area, after the inser-
tion of the piece that has travelled past V — 10. These are doubled, and, after passing
south-westerly 275 feet, another ledge is found 125 feet long. The space between is
occupied by ledges of green and white schists, so that we cannot suppose the conglom-
erate continues beneath the soil. The next space of 250 feet S. 35° W. from V — 11, is
covered with earth. Then succeeds a continuous exposure of the narrow conglomerate
for 1400 feet, with two acute angular bends, the extreme distance of the remotest points
from each other being 740 feet. We find dolomite upon the east and south sides of this
band. Between the northern end of this long crooked string and the southern end of
the next development of the broader band of conglomerate, a distance of 260 feet,
there are three fragments of the rock, disposed at different angles, which would neatly
fill up the gap if placed in the proper position.

The next fragment in order belongs to the greater range, and lies nearly between the
lines 12 and 14, the eastern end extending 100 feet beyond 12. The other limiting

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 307

lines are V and S. The shortest line connecting its remotest extremities is 1300 feet
long; but if we measure tlie length of the ledge as it lies, 300 feet must be added.
There are loops at each end which bend in opposite directions from each other. Tlie
greatest width of this fragment is about eighty feet. On the west side of this frag-
ment, near the easterly end, there goes forth a branch perhaps connecting with several
narrow fragments still further away. We have first an exposure between V — 12 and 13 ;
600 feet north-easterly, by the side of the road, is another narrow band, flanked on the
east by dolomite, which is only 250 feet north from the nearest angle of the looped and
twisted area near Aldrich's house. In the field north of the road are at least two other
exposures of narrow dimensions, which I have followed more than fifty rods. It may
extend still further : I have not traversed the region further in search of it.

There is another exposure midw^ay between U and T — 14, 200 feet
north from the west end of the large fragment with the double hook,
which is probably a part of the range. If we take this isolated fragment,
and add to it another over 300 feet long lying between T — 15 and 16, we
shall have more than half enough material to fill in the 600-feet gap be-
tween the double hook range and the next one to the west. Should we
straighten out this westerly fragment, and then put in these two pieces,
there would be enough to join the larger fragments together by a curve.
I cannot otherwise understand the existence of the mass between T — 15
and 16 than by supposing it to have been forced out of the vacant space
just mentioned. Accepting such a conclusion, it will be seen on inspect-
ing the map that this piece has been thrown very singularly out of its
place. The forces that should so derange the continuity of the forma-
tion are almost inconceivable.

The piece coming next in order is the largest yet encountered, lying
between T — 15 and Q — 18, 1760 feet in length by the shortest line, and
1900 feet when measured along its centre. The general course is about
east and west, but the eastern extremity, for about 500 feet distance,
courses about N. 20° E. This end is 100 feet wide ; the other is twice
that width for 700 feet. It is this fragment that has furnished pebbles
of jasper. The jasper I have seen in a ledge about a mile distant in a
northerly direction, and that may have been the source whence these
constituent pebbles came.

The next fragment of conglomerate illustrates clearly our theory of
breaks and throws. It is a mass 700 by 400 feet, with the course N. 35°
E., whose northern end is 400 feet remote from the nearest corner of the

308 STRATIGRAPHICAL GEOLOGY.

previously described fragment of conglomerate, whose course was said to
be about east and west. By examining the map it may be seen that this
fragment will nearly fill the vacant space existing between the east-west
range and a smaller one to the west between P — 18 and 19. The north-
ern end of this fragment must have been thrown 450, and the southern
end 900 feet ; and its very great width suggests the accumulation of bulk
by folding up the original sheet. Perhaps for the whole of the distance
the mass has been pushed horizontally. The lower fragment near P — 18
is only 350 feet long, running a few degrees north of east. The dip is
70° northerly. Between this and the ledge next J. Williams's house, a
distance of 3650 feet, the rock is clay slate, rather more friable than
usual, and is believed to cover up the conglomerate. The ledge at Wil-
liams's is 200 feet long, dipping 80° S. 35° E., rising precipitously twenty
feet above the road. It is known to be auriferous, by assays.

In the valley of Smith brook the rocks have been deeply excavated and
covered with sand, so that for a distance of 800 feet no ledges are discern-
ible. We then find a large conglomeratic mass having the shape of the
letter L, the upright part being 800 and the horizontal 550 feet long.
The upright part is in the same line with the two previously mentioned
exposures, and the other runs S. 35° E. The country is w^ooded, and
hence the ledge cannot readily exhibit its shape, as it does elsewhere,
rising like a rampart above the adjacent land, not forming the crest of
the hill, however. The western and northern walls are the most promi-
nent, rising perpendicularly twenty-five feet for several rods. The north-
ern slope is covered by enormous blocks of stone separated by frost from
the ledges, and then fallen a short distance down hill.

The connection between the next conglomerate masses is not under-
stood. We have first a fragment 500 feet from the end of the L running
N. 35° E., save that the northern end is bent towards the greater mass to
the east. It is 400 feet long. The larger fragment is conical in shape,
when viewed horizontally, or as projected upon the map, the longer diam-
eter being 500 feet and the base 400. The base is at the foot of a preci-
pice, say 150 feet high. Near the upper part excavations have been made
into the ledge in search of gold, and it was known formerly as the " Dow
mine." The aspect of the fragment oftentimes seems like that of an
anticlinal plunging beneath the hill, with a cap of dolomite. There is

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 309

certainly an accumulation by shoving of an unusually large mass on this
hillside. In favor of a synclinal structure we have the apparent starting
out of two conglomerate lines from the Dow ledge, spreading out 2000
feet before reaching the south town line, and uniting again in the north-
ern part of Bath. To the east of the Dow ledge, 400 feet, there is
another fragment whose northern end touches the hill in the same way
with the last, and capped by dolomite. The fragment is 800 feet long,
at first N. 35° E., and then with a more nearly north-south course. It
nearly reaches the road from Lisbon village over the hill to Smith brook.
A hill between this road and R. D. Moulton's house on the Bath line has
the same general course, and appears to be underlaid by conglomerates,
800 feet long. On the opposite side of the valley there is a ledge of the
conglomerate running 1000 feet S. 35° W. up the hill before reaching the
Bath line. A line of boulders running easterly from the north end of
this last named fragment, between B — 17 and 18, is suggestive of a bend
towards the Dow ledge. This ledge on the west side of the valley rises
to the top of the hill, and then passes by the house of H, Ash in Bath,
and continues uninterruptedly nearly to the brick house occupied by M.
L. Sanborn in Bath, a distance of one mile and seven eighths in a right
line. I have protracted carefully upon the map, measured with chain and
compass, the various bends of this formation in Bath, and will not par-
ticularize the details here. There are about thirty angles made in its
course, which might be mentioned in detail. There is frequently a high
wall upon the western side, as in the south part of Lyman. Dolomite
beds cling to it continuously on the west side. At the lower end the
course reminds one of escalloped embroidery. Concerning the relation
of the slates, Lyman schist, and conglomerate at this lower end, sufficient
mention has already been made (page 293).

While the western side of the basin, if it may be so called, is continu-
ous, the eastern has been badly shattered. Near the town line there is
a fragment a third of a mile long, roughly parallel to the western belt,
about the same distance apart as before, above R. D. Moulton's. Farther
south we find only remnants, five pieces scattered for half a mile, begin-
ning five sixths of a mile south of the town line, and terminating fifty
rods east of the western belt, where it bends sharply to the east for about
forty rods. No other fragments occur save for the last half mile before

310 STRATIGRAPHICAL GEOLOGY.

reaching- the southern end of the basin. The junction there is not regu-
lar, but through a fault. The irregularities on the eastern side may be
due to the elevation of a considerable band of Lyman schists, starting
near the line and extending north-easterly towards the Dodge gold mine.

A few isolated patches of this conglomerate occur south of Aldrich's
in Lyman. One has been known as the gold mine of Tute & Co., at
U — 7. The ledge is one hundred feet long, running north and south.
There is a smaller patch of it at O — 7, with the strike N. 80^ W. The
relations of these isolated patches to the great ranges have not been con-
jectured.

The phenomena of the occurrence of auriferous conglomerate along
the eastern range of the Lyman group are similar to those just enumer-
ated upon the western belt. The most northerly fragments occur from
half to a quarter of a mile south-west from Mill brook in Lisbon, on the
road from a saw-mill to C. E. Woolson's (county map). These ledges
run N. 63° E., dipping 75° N. 27° W., and are fifty feet wide. Like
the conglomerate mass on the hill east of the New England Reduction
Works mine, it is flanked on the east by Helderberg limestone, though
in very limited quantity. The next conglomerate ledge occurs in Lyman,
nearly two miles to the south-west, and reaches from near J — 2 to H — 3,
a distance of iioo feet. The dip is 75° south-easterly. This fragment
is often one hundred feet wide, flanked by Lyman schist. Its continua-
tion is 1200 feet further in the same direction, with a slight easterly dip.
The fragment is straight for about five hundred feet, when it is bent
southerly at a right angle, and disappears. Large boulders of it may
show its continuance for over a hundred feet; and there are a great
many pieces of it for 1000 feet between B and C — 5, which are sugges-
tive of the occurrence of ledges there. Two fragments, near A — 5 on
the town line, may belong to this band, each two hundred feet long, and
the nearest one three hundred feet from the eastern belt.

The eastern belt is continuous from a swamp midway between E and
F — 2 to a point one hundred and fifty feet into Bath, below A — 4, 2850
feet in length. At the north-western end it runs east and north, and at
the Bath terminus its course is from N. 30°-40° E. It is usually seventy
feet wide. At the Gordon mine, between C — 4 and D — 3, the dip is 60°
S. 32° E. Five hundred feet farther north the dip is in the opposite

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 3 II

direction. At A — 3 there is a mass one hundred feet wide, vertical,
running nortli-east, and seen for five hundred feet distance. The two
bands probably make a synclinal axis with each other, as in the main
range. AH the phenomena in the two ranges are identical.

Topographically speaking, the conglomerate ledges always occupy the
highest ground. The eastern bands just mentioned in Lyman average
about a thousand feet altitude above the sea, falling off after entering
Bath, where the whole country slopes towards the Ammonoosuc. While
the western band is usually greatly elevated, it does not follow the crest
of the hill beyond the vicinity of Aldrich's. From about V — 12 to J.
Williams's, there is a uniform descent of nearly seven hundred feet. The
great depression along Smith brook I have thought may indicate a sink-
ing of the strata, rather than the complete result of erosion. Such a
supposition may aid us in elucidating the marvellous changes in the sur-
face of the country since Huronian times. To the south of Smith brook
the country rises, but not so greatly as at Aldrich's, and it falls off to
about the level of Smith brook at its southern termination. The topog-
raphy of the eastern belt of the conglomerate agrees essentially with that
of the western.

Cambrian Clay Slate.

From northern Massachusetts to Fairlee pond, Vt., there is a nearly
continuous band of clay slate believed to be of Cambrian age. As may
be seen upon the map, it lies to the west of the Huronian. Occasionally,
as at Norwich, there seem to be limited bands of this formation left in
the synclinal axes, as relics of its former extent, covering over the green
schists. If wc continue the line of outcrop northerly, it strikes across
Bath and Lyman exactly in the course of an extensive development of
the same rock, occupying the centre of the Ammonoosuc gold field, and
isolated from all connection with similar layers elsewhere. For this and
other reasons it is probable that the Ammonoosuc slates belong to the
same range with those farther south in the Connecticut valley, and that
all of them are to be regarded as Cambrian, or of the same age with the
auriferous slates of Nova Scotia, called the representatives of the Eng-
lish Lingula flags, by Selwyn. Nevertheless, it is true that there is also
a range of this slate west of the Huronian, above the mouth of the Pas-
sumpsic river in Vermont.

312 STRATIGRAPHICAL GEOLOGY.

Viewed in a general way, the slates appear as a single basin, with a
normal synclinal dip evident at the south end. Older rocks have pro-
truded themselves into the midst of the slates, having been pushed up
from below through lateral pressure, thus punching holes, as it were,
through the more yielding material. As a whole, the dips along the
borders have not been affected, though there are many local exceptions.
Often, where limited patches of the slate remain, their dips conform to
the synclinal disposition. If the underlying rocks have been thrust
through the slates near the eastern border, the remnants preserve their
proper north-westerly dip ; or, if the disturbance has been upon the west-
ern side, we discover the normal south-westerly dip remaining. At the
south end of the formation in Bath, the pressure has been so great that
the strata stand nearly upon their edges. The general attitude is anti-
clinal, dipping 80° south-easterly by S. M. Lang's near the eastern border,
and north-westerly near the junction with the western schists near B. C.
Child's. Yet the underlying schists conform to the proper basin struc-
ture, dipping north-westerly at the town-house, and south-easterly at W.
Lang's, west of B. C. Child's. . The altitudes of the lower and upper
series are portrayed upon Fig. 29, Plate XIII.

The lithological aspect of the slate is uniform all over the basin.
Analyses by Prof. Seely indicate a close similarity between these slates
and the argillitic mica schists of the Lyman group in their ultimate
constituents, so I have suggested the derivation of the former from the
degradation of the latter. The slate at the Dodge mine gave, — silica,
72.98; peroxide of iron, 6.35; alumina, 5.99; magnesia, 0.36; potash,
5.61; soda, 9.92=101.21. Veins of auriferous quartz and an occasional
thin bed of quartz conglomerate are the chief foreign rocks present. It
is likely that careful analyses of the slates from different parts of the
basin would show a considerable variation in composition, especially in
the amount of silica. The constancy of mineral composition may be a
useful guide to us in distinguishing between the Cambrian and Helder-
berg slates, where they come into close contact with each other.

Excursions along the eastern border of the slate in Bath show a uniform north-west-
erly dip between the Lyman line and the nearest road crossing it to Bath village. At
the tunnel, or ancient mining excavation for coal opposite the south end of the aurifer-
ous conglomerate, the dip is 30° N. 42° W., the rock being black and carbonaceous.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 313

Nearer the eastern edge the dip takes the direction of N. 62° W. The variations in
the dip, caused by the elevation of the Lyman group near its southern end and at J.
Clough's, have already been specified. The normal dip of N. 72° W. is apparent 300
feet west of the conglomerate. It is the same a little further on at the brook crossing
the road just west of J. Clough's. The western side of the basin is reached at G. A.
Wood's, the dip being 80° S, 55° E. Near the west border we have several positions
noted : West of Wood's, S. E. ; at W. S. Wood's, 85° N. 87° E. ; half a mile north,
south-easterly; at A. Wood's, 75° S. 47° E., and also at other places along the same
north-east road. Occasionally along this route are a few feet thickness of schists inter-
stratified with the slates ; and a vein of auriferous quartz in the shelly strata near A.
Wood's.

As soon as we cross the Bath line into Lyman the slates greatly diminish in amount,
owing to the elevation of the underlying strata. Continuing north-east from the house
of A. Wood, we find at J. M. Moulton's (county map) a shelly mass about 85° S. 50°
E. Just west of L. Whiting's there is a remnant of the slate with a north-east strike,
separated from the main mass. Bands of it weather dark, and carry crystals of pyrites.
At A — 20 and A — 21, on the town line, the position varies from 85° S. 42° E. to 90°.
The position is much like this all over the western corner of the specially-surveyed
area west of the conglomerate, and it is on high land. The slates cover much ground
between J. Williams's and the great throw above P— 18. East of Williams's the dip
is 85° S. 42° E. (See Fig. 30.) For a space 1500 feet long and 1000 wide the dip
is much the same, often inclining to vertical, and occasionally leaning south-east-
erly, slightly. The strike is N. 38° E., with vertical dip at J— 20. Between O— 19
and 20 the vertical slates strike east and west. At O — 19 the dip is 'j'j^ southerly. The
rocks here are quite ferruginous. Between the conglomerate ranges at B — 16, and
largely over an area 2000 by 2500 feet, the position is 70° N. 32° W. The slate at
V— 18 dips 80° south-easterly. The slate area of perhaps 1500 by 2000 feet, near the
Parker Hill road from Lisbon and north of the line T, averages 82^ northerly.

Passing to the lower part of Lyman we find three slaty bands, all divisions of the
eastern part of the basin. The first extends beyond the line F, and the strata are often
much corrugated and broken. Near C— 2, at a quartz opening, the dip is 50° S. 37°
E. Between A— 2 and 3, just over the Bath line, the dip is 25° N. 37°-40° W. Be-
tween B— 4 and 5 a small fault may be seen at the junction of the slate and conglom-
erate. The former has the strike N. 38° E., and the latter N. 68° E. The course of
this fault is N. 28° E. Both rocks are inclined about eighty degrees. At E— i, by
the roadside, the average dip of the crumpled slates is 50° N. At F— i the dip is
70° N. 50° W. It stands vertically five hundred feet west. Between G— 2 and H— i
there is an isolated slaty fragment caught in the Lyman schist, about six hundred feet
long and one hundred wide, standing on edge and running about N. 80° E. On the
band of slate from 12 on the town line to the Bedell gold mine we find, near B— ix,
the dip 50° N. 17° W. ; east of B— 12, 45° N. 27° W. ; west of D— 12, 50° N. 32° W. ;
three hundred feet farther north, 60° N. 42° W. These slates split readily into large
VOL. 11. 40

314 STRATIGRAPHICAL GEOLOGY.

slabs. At E— II the dip is 50° N. 27° W. At G— 10 the dip is 68° N. 20° W. to N.
12° W., five hundred feet farther to the north-east. At the Bedell mine the dip is 80°
N. 22° W. On the next range to the north-west, between F — 13 and 14. the dip is
80° N. 32° W. ; at F — 14, the same ; on the road near H — 12, 70° N. 12° E. ; below
G — 12, 90°, with strike of N. 78° E. ; near H — 10, 58° N. 13° E. ; four hundred feet
farther east, 67° N. 12° W. ; between H and I— 9, 60° N. 8° E. ; near 1—8, 80° N.
32° \V.

Returning to the main range, we find immense slate ledges near Dr. Brown's barn,
at the end of a road about G — 6, dipping north. On the crest of the hill north-west
the slates have the same strike, but stand vertically. East of the barn the dip is 50°
north. The position is the same north of H — 5. At L — 5 the dip is about 20° west
of north. It is 68° N. 20° W. at M— 5. Between N and N— i the dip is 65° N. 37°
W., the strata being much contorted. The same fact is true of the boundary line from
here for 3000 feet westerly. The Lyman schists on the south-east usually form a low
hill or precipice immediately adjacent to the extremely bent slates. It is likely there is
more or less of a fault all along the line. About a third of this boundary is obscured by
a swamp. The presence of the fault is further confirmed by the high Lyman schist hill,
near Titus's house, which is full of contortions. Where the color for slate is spread
out to the north (P — 5), I find evidence of a bending of the rock. Opposite the angle
between P and Q — 4 the dip is N. 48° E., and that is the common position in the neigh-
borhood. It gradually works around to the normal position of N, 35° W. at the Dodge
mine. The same change is apparent in proceeding south-westerly from the N. 48° E.
dip. Some of the ledges near the angle show marks of disturbance. I suppose the
strata have been bent here especially, because of the projection of the underlying Ly-
man rock. These facts do not militate against our theory of the unconformable cov-
ering of the Lyman rocks by the clay slates.

Other dips are the following :

200 feet south of O— i, dip 44° N. Brook between S and S— i, dip 60° N.

200 feet west of O — i, dip 50° N. 8° W. 32° W.

Between O and O— i, 60° N. 62° W. Between T and T— i, dip 50° N. 22° W.

200 feet west of P— i, dip 85° N. 14° W. 100 feet N. W. from T— i, dip 48° N. 47°

Between P and Q, dip 85° N. 12° W. W.

Between Q and Q— i, 45° N. 37° W. Between V— i and 2, dip 56° N. 42° W.

At R, vertical, strike E. and W. 200 feet N. W. of X, dip 28° N. 17° W.

Between R and R— i, dip 62° N. 12° W. At R— 6, dip 65° N. 12° W.

Between R and S— i, dip 41° N. 47° W. Near S— 6, dip 72° N. 32° W.

300 feet north of last, dip 40° N. 22° W. Near U— 6, dip 87° N. 12° W.

The relations of the slates to the knobs of white quartz in the Lisbon
group, showing unconformity, have already been treated of (p. 282). The
dip of the slates is very high north-westerly across the formation half a

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 315

mile north of the Hne V, as exhibited upon Fig. 31. On the north side
of the outlet of Young's pond the slates dip 78° S. 32° E. At the town
line below, the dip is 60° N. 52° W. North of the pond, on the south
flank of Mormon hill, the dip is usually high north-westerly. As before
stated, the west boundary of the slates is roughly serrated. Near the top
of the hill, adjacent to the curious conglomerate, are ledges of slate, hold-
ing veins of quartz eight feet wide, cutting across the stratification. The
dip is N. 47° W. This seems to be the end of the clay slates proper in
this direction. There is slate by the saw-mill on Mill brook, below
Young's pond, also at S. Wetherby's, on the hill west, both with the
usual dip noted farther south-west. On the west side of Perch pond the
dip is 70° N. 32° W. On top of Bald hill the same slates dip 40°-6o°
N. 42° W. Beyond this they occur at Ela's, where there has been a
quarry, the last house in Lisbon on the Blueberry Hill road. The whole
of the Blueberry Mountain slates, with their argillaceous schists and
sandstones, seem now, after further study, to belong to the Cambrian
group and not the Helderberg, contrary to the delineation of the map
(Fig. 27) and published papers. For convenience, we will describe them
further on in connection with the several sections crossing the Helder-
berg strata.

We have very little to say concerning the considerable development of
clay slate from Parker hill to Partridge pond. The dip in the south-west
part is thought to be south-easterly. There are irregularities in it two
miles before reaching the north line of Lyman, on the road to West Lit-
tleton. South from Partridge pond the slates stand nearly vertical, with
a north-east strike. There is a narrow band of clay slate dipping south of
east, conforming with the Lisbon schist at the east base of Gardner
mountain. We have notes of it, also, at E. C. Stevens's, a mile north,
and in West Littleton at the north base of Gardner mountain. It is
rather more micaceous and ferruginous than is common in the larger
areas. It points towards the tapering end of the Lyman group across
the Connecticut river in Vermont. There are two or three very small
patches of slate in the north-west part of Littleton. One of them has a
quarry in it, at R. Smith's.

3l6 STRATIGRAPHICAL GEOLOGY.

Coos Grouj

Two areas referable to the Coos group constitute much of the eastern
boundary of the tract now being described. The first enters Littleton
from Dalton, crosses the Ammonoosuc near Littleton depot, and rises
into Eustis hill. The north end is about two and a half miles north-east
from the Littleton line, dipping near J. Ouimby's in a westerly direction.
There is a considerable hornblende schist between the mica schist and
the gneiss. The band is about a mile wide where it enters Littleton
upon Mann's hill. The common or Lake gneiss borders it on the east
in Dalton, but in Littleton it comes in contact with porphyritic gneiss,
and on the west at first the Huronian. Further along it may touch the
Helderberg, but for two or three miles it borders gneiss, especially on
Oak hill and at the village of Littleton. At A, Annis's the dip of the
mica schist is 70° N. 37° W. Part of these ledges north of Mann's hill
are calcareous, reminding one of the calciferous mica schists of Vermont.
Towards the crest of the hill and the western border of the formation,
the dip is 70° N. 52° W. Beds of hornblende occur in it, also. On the hill
west the dip is 70° N. 70° W. of mica and hornblende schists. Another
dip is 30° in the same direction, in ledges containing many staurolites
and garnets. There are a few feet thickness of granite associated with
the staurolite beds near Annis's. A mile farther south, near the road
turning to Smith's slate quarry from Mann's hill, the mica schists dip
80° N. 55° W., and also west. Where the formation crosses the road
near P. C. Wilkins's, the strike of it is N. 22° W, It was noticed that
the layers were somewhat twisted, and contained large hornblendic nod-
ules. It seems therefore to run athwart the underlying Lake and porphy-
ritic gneisses in an unusual direction, and, of course, unconformably. The
mica schist then proceeds southerly to Scythe Factory Village. It out-
crops in two or three places along the railroad on the east bank of the
Ammonoosuc. One ledge of it, by a mill-dam, exhibits the dip 75°-8o°
N. 22° W. Three fourths of a mile east on the railroad there is an iso-
lated outlier of it. Opposite the new scythe factory the micaceous quart-
zite dips 80° N. 37° W. With it are intcrstratificd argillaceous bands,
sometimes wrinkled. The gneiss crops out at the second dam at Scythe
Village. Perhaps a fourth of a mile above, on the railroad, the micaceous

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

317

quartzite reappears, carrying staiirolite. The dip is 65° westerly. The
actual junction of the quartzite and gneiss may be seen on the Ammo-
noosuc, near where the railroad has cut a passage
through a ledge of gneiss. Certain layers here and
in the village of Littleton are properly micaceous
quartzites, of a type that is characteristic of the Coos
group in Stewartstown, Vershire and Thetford, Vt.,
and at various other localities. In the river, near
the Littleton depot, the dip is 80° northerly. On
Eustis hill it is 57° N. 27° W. This formation is
the same with that coming from Whitefield, east of
the Boston, Concord & Montreal Railroad, on Kim-
ball hill, and extending nearly to the Wing Road
junction. Both these ranges may once have been
united near Littleton, and crossed over the hill of
Bethlehem gneiss to join the Lisbon area about to
be described.

The Kimball Hill range of these Cobs mica schists is rep-
resented upon Fig. 34, which is partly the same with Fig. 11,
PI. VIII. The latter figure shows the unconformable super-
position of the mica schists upon the Lake or Atlantic gneiss,
which is not separated here from the Bethlehem series. Some part of the valley be-
tween 2 and 3 is occupied by porphyritic gneiss. As the country is swampy and
wooded, it is difficult to trace the limits of the several formations within it. Farther
north there are patches of mica schist outcropping in it.

The rocks of East Lisbon abound in staurolite, the ledges about Mink
pond having been long known to mineralogists. This area, the second of
our description, was separated from all other rocks in our first report, in
1869, under the designation of "staurolite schists;" and there is very
little change to be made from that representation of its topographical
distribution, save that the argillaceous division west of it is now incor-
porated with the grayish mica schists. The three leading varieties of
this formation in Lisbon are (i) quartzite, (2) staurolite mica schist, (3)
stauroliferous and garnetiferous clay slates.

Of these the quartzites occur chiefly in a narrow strip colored as gneiss
on some of our maps, extending from the South Branch half way through

3l8 STRATIGRAPHICAL GEOLOGY.

the township. They follow a road parallel to the Ammonoosuc between
the South Branch and Salmon Hole brook. Near the South Branch we
have in order, proceeding northerly, gneiss, slaty layers, perhaps slightly
calcareous, dipping 80° north-westerly, quartzite, with a dip of 75° S. E.,
limestone, and quartz. This series is only a few rods wide. Quartz and
limestone, with gneiss, are found along this road nearly to Salmon Hole
brook (near J. Hildreth's) in a very narrow band. The quartzite is evi-
dently older than the adjacent staurolite schists, and the structure may
be anticlinal. The limestones are connected with the gneiss, being of
the same age with the bed at Bronson's kiln. The quartzites are rejDre-
sented in the Ammonoosuc collection, in Nos. 2S;^-y88. See, also, the
Map, PL XH.

The Coos area east of the Ammonoosuc naturally divides itself into
two parts mineralogically, the western consisting of clay slates, with
many garnets and a few staurohtes, and the eastern part being a mica
schist, everywhere stauroliferous, and often holding magnificent crys-
tals. The slates at the upper end occupy about half the space between
the quartzite range and the Huronian, At the south-west end of Streeter
pond the dip is N. 27° W. at a high angle. A mile west the position
is the same. Near the mouth of the South Branch, at a bend in the
stream, these slates dip 60° N. 29° W., and are exposed for a width of
thirty rods. The relations of the slates to the adjacent Huronian and
Helderberg strata are given further on, in a section under the descrip-
tion of the latter rocks. On Salmon Hole brook these slates dip 85° W.
The section in Fig. 28 crosses this and the schistose band farther south
along Mink brook. The thickness of the clay slates here is given at
3000 feet, with an average dip of 58°, and that of the schist at 3300 feet.
Beginning at the Atwood gold mine on this section, the following were
the dips observed across the slates : 48° N. 62° W., 50° N. 67° W., 64°
N. 57° W., 68° N. 62° W., and 65° N. 32° W. The distance is about fif-
teen sixteenths of a mile. These slates terminate on the west side of
Pond hill in Landaff, with the dip 58° N. 32° W.

The mica schists begin in the edge of Bethlehem, south of W. Bur-
leigh's, on the road from Littleton to Franconia, with the dip 20° N.
57° W. The valley continues to Baker's hollow in Bethlehem; and it
would not be surprising if the staurolite rock extended further in that

GEOLOGY OF THE CONNECTICUT VALLEY DLSTRICT. 319

direction, as the ledges there are all covered by drift. There is a beau-
tiful display of large staurolites on the road from the furnace, a little
north of west over a hill towards the north-west line of quartz, passing
by the names D. A. Oakes, J. Bowles, etc., of the county map. On Sal-
mon Hole brook the staurolite mica schist agrees with the slate in posi-
tion, viz., 85° W, Recorded observations are meagre north of Mink
pond ; but the usual dip is north-westerly to westerly. A hornblende
schist occurs near H. N. Page's, on the west side of the gneiss and
quartz ridge. Near Mink pond the dips are 65° N. 57° W., N. 42° W.,
and N. 72° W. (See Fig. 28.) The formation narrows in proceeding
southerly into Landaff. It seems to cross Mill brook three fourths of a
mile below the village, the garnetiferous ledge dipping 80° N. 52° W. It
may possibly be represented in argillaceous schist layers near the school-
house at the west base of Green mountain ; though we have not yet fully
established in this neighborhood the boundary between the Coos and
Swift Water series. We find quartzite by the Baptist church, about a
mile from the north line of Landaff, dipping at a low angle north-west-
erly, and a larger conglomerate exposure west of W. Hunt's. Our notes
speak of quartzites also following the limestone of the Bronson range in
Lisbon. These are on the same strike with the outcrops at the Baptist
church and at Hunt's. The range is parallel with that on the north-east
road between Jesseman's and Hildreth's, and may occupy a synclinal fold
of the same stratigraphical horizon with that. The latter line of out-
crop may divide the mica schists stratigraphically, as it does territorially.
There is no evidence to prove that the slates on the west of the schists
have been folded. The quartz is beautifully developed farther south
through Landaff, Benton, Haverhill, etc., passing into the mountainous
masses referred to the Coos group. These will be described further on,
in the next division of the Connecticut Valley rocks.

There is considerable variation in the aspect of the staurolite rocks.
We have fine-grained homogeneous clay slates, with slender staurolites.
Then there are coarsely-crystalized ledges of mica, staurolite, and garnet.
Perhaps the most characteristic is an argillaceous schist, with numerous
stems of staurolite about three inches long, of a reddish-brown color,
cutting through the rock in various directions. The staurolite is also
found in a gray micaceous rock, and in the western edge of the gneiss

320

STRATIGRAPHICAL GEOLOGY.

by Mink pond. Some of our specimens suggest the existence of the
Coos slates to a limited amount upon Walker hill and its neighborhood,
the continuation of the Eustis Hill range from Littleton lying between
the Bethlehem and Swift Water series. The last that can be depended
upon is at P. H. Padelford's, at the south line of Littleton,

Swift Water Series.

While occupied in studying the geology of the gold field, I found a set
of specimens which could not be readily referred to any of the series that
have been mentioned. They approximate nearest to the
Lisbon group, and occupy the territory east of that for-
mation. Its whole extent from Haverhill to North Lis-
I bon (Fig. 28, p. 278) shows the position of this series
^, in the typical section, crossing the east part of the field
I at Lisbon village. The combined thickness of the quart-
S zites, sandstones, hornblende schist, and slates amounts
^ to 4400 feet.

I Our attention was directed to this group partly by the
s slate bands, and partly by a nondescript conglomerate
". adjoining it, particularly noticeable a mile and a half
I north from Lisbon, west of Mrs. A. Bishop's, on the
I north-west side of the river. The pebbles are not dis-
I cernible till the rock has been weathered nearly white,

o

^. and even then it is difificult to understand their charac-

^ ten This band is not more than fifty feet thick.

« Following up the Wild Ammonoosuc river in Bath,

S there is a characteristic representation of this series of

'^- strata; and our name is derived from that of a small

I village on its banks. The facts given are chiefly from

I the notes of Mr. J. H. Huntington. The Lisbon group

to

I seems to extend up this stream for more than a mile
above its mouth, judging from its general distribution.
A little above a starch factory (Fig. 35) there are strata
of micaceous conglomerate, of gneissoid aspect, dipping
40" N. 65^ W. The slate, or the continuation of the Lisbon band, is half
a mile above the factory, and it dips 65° N. 82° W. Less than half a

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 321

mile above is a more distinctly gneissic band, dipping 56° N. 62° W.
About the village of Swift Water are various exposures of a whitish mica
schist, from 40° to 55° dip in the same general direction. There seems
in many cases to be feldspar present ; certainly a hasty look would make
the ledges to be gneiss. On the north side of the river one ledge dips
50° N. 2° W. There is a band near a cemetery, in the south-west out-
skirts of the village, containing crystals of chlorite. Passing above the
village the dip rises to 80° and more, or, in order, 83° N. 54° W., and 82°
N. 74° W. The last is the most remote exposure seen. The rocks are
micaceous friable quartzites, decomposing so as to appear ferruginous.
There are thin, glossy black micaceous bands, of a few inches in thick-
ness, interstratified with the quartzites. This is at a bridge a mile and a
half above the village. A wide band of hornblende schist below the
bridge should not be forgotten. The gneiss above has a high dip. It
is possible that an anticlinal axis may be indicated by the divergence in
the steepness of the dips. There seems to be a prolongation of a spur
from the gneiss of Haverhill directly to this point of dip-divergence.
There is considerable lithological similarity between the rocks along the
Lisbon and Swift Water sections.

The slate band (No. 4) of the section is quite interesting, as it can be
traced to Lisbon village, and perhaps Littleton, bounding the series on
the west. A conspicuous locality of it is at L Clark's, about two miles
east of Bath village. Going south-east from J. M. Nutter's, for a mile, the
following three dips were noticed: 80° N. 50° W., 68° N. 52° W., 60° N.
42° W. The rocks are mica schists, also, at W. Bass's. Ninety rods
south of W. Waddell's, the rock adjoining the mica schists is chloritic.
A quarter of a mile south-west of the Hon. A. S. Wood's we have mica
schist and hornblende rock somewhat calcareous. Next L Clark's slate
there is mica schist, and a slightly chloritic rock sixty rods north. Mica-
ceous quartzites occur half a mile south-west of S. Clark's, on the Bath
line, at L. Elliot's, and at J. Chandler's in Landaff. At S. Clark's there
is a mica schist, with acicular hornblende. By J. Chandler's we find a
little of the Coos group, also. West of Mrs. Bishop's, in connection with
the conglomerate referred to above, the dip is N. 40°-58° W. Across
the section, in Fig. 28, we have the following dips proceeding east : Slate,
60° N. 60° W. ; hornblende, 50° N. E., 50° N. 6f W. on hill-top, also
VOL. II. 41

322 STRATIGRAPHICAL GEOLOGY.

quartzite with smaller dip ; sandstone, 70° N. 66° W. ; hornblende layer,
70° N. 62° W. ; and rock at Atwood's gold mine, 50° N. 72° W,

As at present advised, the rocks north of Lisbon village may be thus
classified. At the railroad crossing is the Swift Water slate, continued
northerly from I. Clark's, which seems to point across the river to join
the ledges associated with the conglomerate west of Mrs. A. Bishop's.
Nearly two miles of exposure next are concealed by the meadows. A
little white quartzite, once thought to resemble Bethlehem gneiss, appears
by M. Kimball's ; then the Lisbon group as far as W. (not S.) K. Chase's
up the Ammonoosuc. These dip high north-westerly. As mentioned
on page 284, this area of Lisbon rocks seems to be disconnected v^ith
both the other ranges. The hornblende band succeeding dips N, 82° W.
beyond Chase's, and may be seen upon both sides of the river for some
distance. It occurs again at G. H. Buel's, upon Walker hill. I think that
is the branch proceeding towards Fitch hill, while that on the east side
of the river directs towards Streeter pond. (Compare with statement on
p. 284.) This hornblende band is thought to be Huronian. Next are
supposed Helderberg slates, dipping N. 50° W. just before reaching the
Whipple Brook road. Beyond that turn a short distance are calcareous
rocks 75° N. 42° W., followed by fossiliferous Helderberg strata 75° N.
32° W. Then there comes, by J. Dexter's, 2d., and D. S. Richardson's,
a series of micaceous limestones, green rocks, and conglomerates, having
the aspect of the Swift Water series, dipping N. 32° W. This brings us
nearly to North Lisbon, and the peculiar conglomerates and limestones
of the Helderberg group.

These Swift Water rocks seem to be continued at eighty rods south of
W. Morse's house, — a white, soapy rock with quartz pebbles, the slate of
Walker hill used for whetstones, a ledge adjoining the Bethlehem group
west of D. Dexter's, and in general from this ledge across to the road
from Walker hill past W. Jackman's and Col. H. Richardson's into the
south part of Littleton. The ledges along this road dip 55° N. 32° W.
There is a fine development of them on a private road up to P. K. Corey's
in Littleton. Near his house the sandstone rock dips 70° N. 52° W.
South of the house the schistose rocks dip 75° N. 52° W., and there are
a large number of ledges. These Swift Water rocks are not seen farther
north-east, being covered by the alluvium. The Cambrian joins them
on the west.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT, 323

Our general impression of the age of this new series is, that it is alHed
to the Helderberg. The Coos group disappeared finally about two miles
below the Lisbon section, so that the Swift Water series lies contiguous
to gneiss of a very ancient period for five or six miles. Were the pres-
ence of chlorite an index to its age, it would be ranked with the Lisbon
group. No one need be troubled by the apparent dip both of the Coos
and Swift Water groups, as well as of the Helderberg strata beneath the
Lisbon series ; for the lateral force has been exerted so forcibly in New
Hampshire that inversion is the rule rather than the exception.

Postscript. With the view of finally settling the relations of the Swift
Water series to the Huronian and adjacent rocks, I have reexamined the
Ammonoosuc valley between Lisbon and Littleton while the foregoing
pages were being set up, and think evidence is afforded to prove them to
be a part of the Huronian, perhaps the equivalent of the strata developed
along the Upper Ammonoosuc river in Stark and Milan (p. 52). This will
enable us to color the area between the clay slates and the Coos group
in Lisbon as Huronian. The Bethlehem group at North Lisbon may
extend a little farther south-west than appears on Fig. 27, and the small
area of it by M. Kimball's may be eliminated. I also think that the slate
band, spoken of as extending from Swift Water river past I. Clark's to
the north part of Lisbon village, should not cross the Ammonoosuc to
join the rock near Mrs. Bishop's, but continue to North Lisbon, perhaps
dividing above the saw-mill near the mouth of Whipple brook, and the
western branch continuing over Walker hill, constituting the whetstone
quarries there, and outcropping at Paddleford's just in the limits of Lit-
tleton. If there is to remain any relic of the Swift Water series in our
classification, it will be this band of slate. I cannot fully satisfy myself
whether it belongs to the Huronian, Coos, or Helderberg series. Future
explorers of this district may well commence by fixing the age of this
slate. A hornblende band lies adjacent to this slate on the west, trace-
able perhaps from Lisbon village, certainly from about the mouth of the
Salmon Hole brook to W. K. Chase's and the adjacent saw-mill, G. H.
Buel's, J. Clark's, and so on into Littleton at or near Fitch Hill summit.
I suppose the same, or a closely-related hornblende band, courses to
Streeter pond from the Whipple Brook saw-mill. This is the band spoken
of on page 284, and it is to be regarded as Huronian.

324 STRATIGRAPIIICAL GEOLOGY.

A few details additional to what has been already given will now be in
order. The greenish sandstones erop out on the hill south of the Atwood
mine, dipping 70° W. By S. C. Simonds's, next the town line, there are
hard greenstones, not conglomerate, dipping 65° N. 70° W. There are
bands of a white quartzite a little west of the Atwood mine, believed to
be the same with the wliite ledges by M. Kimball's, and near the mouth
of Salmon Hole brook. In following up this latter stream we find the
following order: — First, there are the usual hard dioritic schists of the
riuronian, much like those in the railroad cut, being the same layers in
fact, dipping 65° north-westerly. These layers contain interesting iron
ore nodules, consisting of the specular variety, enclosing hematite, the
latter verging into limonite as it decomposes. The ledge is full of holes,
caused by the washing out of these iron ore nodules. Close to the rail-
road crossing of the stream are micaceous quartzites underlaid by the
white rocks. About a fourth of mile back are large blocks of hornblende
rock, which are supposed to represent this rock as it continues south
from the saw-mill called above "near W. K. Chase's" and the "Whipple
Brook" establishment. It must be in jDlace very near. Next comes the
slate band, occurring at a bend in the stream quite conspicuously. The
remainder of the distance to the display of the Coos slates is mostly cov-
ered by drift; but two or three exposures of conglomerate are visible,
dipping 60° north-westerly like all the strata upon this brook. This is
believed to connect with the coarser "egg" conglomerate at North Lis-
bon, but here it closely resembles the auriferous variety so common in
Lyman. A micaceous schist occurs with it. No other rock intervenes
between this fragmental one and the Coos staurolite slates, which begin
to show themselves three fourths of a mile above the Ammonoosuc. It
is the place for a narrow band of Huronian to occur between this con-
glomerate and the staurolite slates, as appears from the order of succes-
sion at North Lisbon.

Following up the Ammonoosuc, the next outcrop is the massive horn-
blende at the saw-mill, coursing in the direction of G. H. Buel's. The
first ledge above it is a black slate, with many small veins of quartz, much
contorted, and with a strike carrying it squarely across the river. This
is thought to be the continuation of the slate just mentioned, and the
contortions arc due to local compression. It appears distinctly on the

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 325

west side, near the house of P. Ash. Ilelderberg rocks may appear next,
which I will notice hereafter. The following is the order of rocks seen
from D. Richardson's house, up a deserted road towards Sugar hill : At
the house, Helderberg limestone ; measures concealed across the railroad
and field; at the base of the hill, conglomerates, one variety holding stones
of the size of a hen's egg, and the other indurated and composed of small
fragments, together with mica schist, both the same with the rock expos-
ures in the South IJranch. ]5ands of quart/Jle accompany tlic schist, and
all dip 85'^ north-westerly. Close by these schists, and next in order, arc
ledges of the hard Huronian diorites. On climbing the hill for half a
mile, no other ledges were seen. This order of rocks agrees with that
figured in one of the Helderberg North Ij"sl)on sections.

Taking the west side of the river, the following are the rocks seen,
beginning with Chase's hornblende. It appears on the river bank oppo-
site a curious sheep-house, shaped like an old-fashioned straw beehive,
near the house of P. Ash. Then we find the slate band. Between J.
Dexter's, 2d., and D. S. Richardson's, arc schists referred heretofore to
the Swift Water series. Near a school-house is a hard quartzite, like
some Huronian varieties. There is nothing else till we reach the con-
glomerate under the bridge crossing to the station.

On the road from Walker hill over to the south part of Littleton arc
numerous greenish schists, with large, pebbly grains of quartz. The
same occur in large amounts to the north-west towards the house of P.
K. Corey. There is quite a broad band, — say a mile wide between the
slates and the gneiss in the north part of Lisbon, — which belongs to the
Swift Water member of the Huronian. In South Littleton this mostly
disappears beneath the alluvium of the Ammonoosuc, and may connect
with the narrow Huronian band east of the Helderberg by Parker's river.
By such a reference of these strata it is easy to understand the relations
of the several formations along the Ammonoosuc valley. There will be
further reference to them in the description of the sections crossing Blue-
berry hill under the next topic.

IlELDERnERG.

There are three divisions of the Helderberg rocks of Littleton. The
lowest member is quartzitc or buhrstone ; the middle is a limestone ;

326

STRATIGRAPHICAL GEOLOGY.

and the upper a few slates. We have several sections crossing this area,
on which one can see many other rocks besides the Helderberg deline-
ated, and described here for convenience. The first (Fig. 36) is near the
north-east extremity, extending from Palmer to Burnham hill, nearly a
I mile and three fourths. Palmer hill is composed of
Lyman schist, dipping '/^° N. 48° W. In passing to
I the depression, which is in reality a water-shed for
I streams flowing northerly and southerly, — Cow and
I Parker brooks, — the strata, first, are vertical, then
I they dip north-westerly; and, finally, several meas-
^ urements in a distance of thirty rods gave 80° S. 54°
i E, S. 30° E., and 85° S. 45° E. The rock here, near
y C. Closson's house, is an indurated slate, chiefly sili-
■^ ceous. Next we pass up a hill over the Lisbon schist,
t .• perhaps dipping 80° S. 25° E. On top of the hill
0^1, there are good exposures of the Lyman argillitic
I 2 quartzites, dipping 80° S. 37° E. Immediately to
^ I the east succeeds a siliceous rock, which, from dif-
ferent observers, has received the names of sand-
stone and buhrstone. It dips sometimes north-west,
but perhaps oftener to the south-east. On the north
slope of the hill the sandstone varies in position from
about 80° S. 18° E. to S. 2° E. This rock can be
followed a mile north-easterly across the road going
eastward to Mann's hill, or nearly to W. I. Heyer's,
and then is supposed to turn and follow up the hill
to the south-east of Burnham's house, and to con-
tinue south-west to Parker river. It has its maximum
development on the east side of the basin, and prob-
ably connects with the buhrstone of Fig. 38.

Overlying the sandstone, as I suppose, is the fos-
siliferous limestone. It has been excavated at several
places quite extensively, and burnt in a contiguous
kiln. It is usually of a light-drab color, somewhat
brecciatcd; and the fossils are not conspicuous, but upon search they
prove to be considerably abundant. The thickness varies from ten to

2 -t

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 32/

sixty feet. On the north side the limestone forms a precipice of twenty-
feet, in consequence of excavations. It is an excellent locality for large
crinoidal stem fragments. In contact with it, on the section line, is a
slate dipping 80° S. 30° E. I understand this dip, as it involves the
limestone, also, to be an inversion. The Lyman schist and Helderberg
here adjoin each other without the intervention of the quartzite. I find
it also stated in my note-book, that a chloritic rock and a rough mixture
of quartz and feldspar occur with the limestone at the kiln, perhaps as
horses, to use a mining term ; and also the fact of a change of a quadrant
in the strike, in a few rods' distance. The overlying slate is seen to best
advantage in descending the hill toward Littleton. It is rather dark, soft,
splits readily, and contains fucoids and markings like CJiondntes, and
dips south-east. The top of this hill is an excellent place to observe
contorted strata; and, on account of their variation in position, it is diffi-
cult to be satisfied with any interpretation of them,

I do not suppose that all the facts are indicated by so even a synclinal
as appears in the figure. There may be hummocks of underlying rocks
to disturb the continuity; and the strata are certainly contorted. The
limestone was not observed to the east of Mr. Burnham's house ; but, as
the sandstone beyond has a small reverse dip, we may presume that the
limestone changes with it. Still farther to the south-east gneiss occurs.
The country is wooded, and slopes rapidly, and would not be likely to
afford good ledge exposures.*

A mile to the south-west a more satisfactory section may be obtained
(Fig. 37), so far as the position of the strata is concerned ; but the lime-
stone has not been observed. The west end lies in a valley, a tributary
of Parker brook ; and the rock is chiefly the chloritic rock of the Lisbon
group, dipping a few degrees, S. 20° to 30° E. The ground is cleared,
and the ledges common. The junction between this rock and the slates
can be seen to the best advantage near A. Mills's house. At the house
the slates dip 85° N. 20° W., and a short distance south-east 70° S. 30°
E., showing a small synclinal, where the rock was crowded hard. The

* Fig. 36 was constructed from fragmentary observations obtained at two different visits, and was based partly
upon theory. It was drawn several years since. Having had an opportunity to examine the rocks again, though
not sufficiently to thoroughly understand them, I will add in Fig. 36a, to be placed upon some plate further on, a
new delineation of the order and position of the strata east of Closson's house. The slates will there appear to
underlie the Helderberg series, as I found them in the hill south of the house to dip 70° S. 70° W. and, on top,
N. 38° E. The sandstone may be five hundred feet thick.

328

STRATIGRAPHICAL GEOLOGY.

schists, including calcareous limestone, a drusy rock, and diabase, dip

85° N. 80° W. At A. P. Hubbard's, exactly upon the section line, the

i dip is 85° S. 30° E. The soft clay slate is thin-bedded,

tc jointed but not contorted. The same position continues

I two thirds of the way to the house of J. Shute. The

J, last third of the way the slate resumes the dip of N. 30°

^" W., and disturbances are common. The cleavage planes

§ can also be distinguished from the strata in a few ledges.

-^ The quartzite is a rough-looking rock, somewhat like

^ buhrstone, dipping even as low as 35° N. 30° W. The

i; i band of chlorite schist dips 75°-8o° N. W., and corre-

1^^^ spends to a similar rock in the next section holding the

^. c same position. Last of all is the gneiss, dipping at a

^: s moderate angle in the same direction, and probably un-

I 5 derlying unconformably the whole series described. This

^ I section is four hundred and twenty rods long. The slate

a,' -^

.-< I is estimated to be 1490 feet in thickness.

'? The slate is continuous from Fig. 37 to Fig. 38, grad-

I ually narrowing, and disappearing before reaching the

I section in Fig. 39. That which appears on the latter oc-

^~ cupies a slightly different line. Fig.

'i 38 crosses the best locality of buhr-

;! stone, from E. P. Miner's, on a tribu-

i tary of Parker brook, and an eighth

"^- of a mile north of the Littleton cem-
etery. It is one hundred and sixty rods long. The
western edge of the gneiss appears at Miner's. The
chloritic layer is mostly concealed by drift. The buhr-
stone crops out on the hillside: it is quartz, massive
and brecciated, sometimes jaspery and opaline, with a multitude of seams
covered by quartz crystals. About forty feet in thickness of it are ex-
posed. Following up the hill, we find next the slates, the limestone
being concealed by drift. It appears in a place only a few rods to the
south of the section. The slate is bent everywhere, and shows a ten-
dency to contain drusy quartz. Two measured dips are 70° N. 70° W.,
and 85° N. 80*^ W, Other strikes are more easterly. The section, if

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

329

continued, would pass down a precipitous hill and across Parker brook
into a swampy forest.

The next (Fig. 39) is the most important of all the sections, partly
because it is near the travelled road to the Connecticut river west from
Littleton village, and partly because it comes from Sec-
tion IX. It is a mile and three eighths long. The gneiss i
is the Oak Hill deposit, and is in place an eighth of a ;
mile north of the section, with a dip of 3 5^-40° N. 30° i

W. The chloritic rock appears next. It is close by the -" F^i^lili I

n
road, opposite the last house before reaching the Parker |

brook, and can be traced along the ridge extending north- g

east for one fourth of a mile. The dip is 60° N. 60° W., -

with a somewhat higher dip down the slope. The fossil- | x

iferous limestone follows immediately. The first layer '^ ^

seems to conform with the wall rock. At the kiln, which gw

is not fifty feet from the base, it dips 60° N. 85° E., and |f

also westerly. Hence there is a small anticlinal axis. The 3 >-

same fact was also observed farther north, near Fig. 38. '^ |

Directly at the kiln no fossils were obtained : they came 9 s

from a dark layer, with a westerly dip, near the brook. | 'J,

The Zaphrentis and the Favosites, with small crinoidal | ^

fragments, are found here. Geologists have searched for h %.

fossils at the kiln, and, finding none, have concluded that \-

our story about them is a myth ; but they should look in "^

the right place. Dr. C. T. Jackson visited this kiln in |

1 84 1. He says, — "The bed is included in mica slate, em- ^^

braced on both sides by granite, which crowded the lime- |

stone in such a manner as to produce contortions of the ^

strata. The course of the limestone, as indicated by ^

strata marks, is N. 20° E., S. 20° W., and its dip is to the

north-west." He figures the bed as enclosed between two masses of

granite, but does not exhibit any contortions in the strata.*

The alluvium of Parker brook intervenes, and conceals the rock for an

eighth of a mile, perhaps. On the south-west side there are several out-

* Geol. Report, p. io8.
VOL. II. 42

330 STRATIGRAPHICAL GEOLOGY.

crops of limestone, some of them containing coral masses. A slaty mass
with no cleavage is mixed with it. The limestone near the first house on
the west side of Parker brook is bluish, and was at first supposed to be-
long to the Lisbon series, as it is not fossiliferous. It has been excavated
for a kiln in years gone by. Recent researches indicate that the whole
of this hillside, perhaps into Lisbon, is of Helderberg age. The strata
have somewhat of a zigzag arrangement, which need not be described in
detail.

Directly beyond the brick-kiln we find the chloritic rock in its per-
fection, dipping in the same direction with that already noted, but at a
steeper angle, and the range is only thirty rods wide. At a turn in the
road, slate of less width, seemingly vertical, appears ; and we discovered
imbedded in it two feet thickness of compact crinoidal limestone. This
identifies the slate with the deposit upon Fitch hill, a quarter of a mile
to the south-west, where the Pentameras is found. The mingled slate
and limestone extend up the hill, and then across the ridge.

The chloritic rock reappears on the section at a fork in the road, and
continues uninterruptedly for three eighths of a mile, dipping 75°-8o°
north-westerly. This would give a thickness of about 1900 feet of strata.
This is undoubtedly continuous to the west end of Fig. 36 in one direc-
tion, and to the ledge under the slate quarry in the other, a distance of
about three miles.

The Fitch Hill locahty was discovered September 22, 1873. Mr. J. H.
Huntington and A. S. Bachelor, of Littleton, and myself composed the
exploring party; and Mr. Huntington first detected the presence of the
Pentamerus. Our attention was called to the spot by Mr. A. R. Burton,
of the village, who had seen limestone there. It is about fifty rods south-
erly from E. Fitch's house, in an open pasture, near the forest and above
an orchard. The first rock seen above Mr. Fitch's is the chloritic feld-
spathic layer of the Lisbon group, running N. 55°-6o° E., and containing
a layer of white quartz. In the pasture the strike changes to nearly east
and west; and this fact is made certain by the position there of the white
quartz, which curves with the Lisbon rock, but may be a little nearer the
Helderberg after the bend is passed than before. This is confirmed by
examining the rocks east of the Helderberg range. On Fig. 39, below,
there are thirty rods of chloritic rock east of the slate range, but on

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

331

Fitch hill, in consequence of the transverse course of the latter, it is
wanting, as shown in Fig. 40. To the south-west there is another out-
crop of this older range, and the Helderberg is cut off by it ; but the fos-
siliferous seam again covers it when the low ground is reached, and the
hard rock is seen no more.

Furthermore, the contact between the Helderberg and the diabase or
chloritic strata on Fitch hill is not a direct succession or interstratifica-
tion, since there has been a sliding of one rock over the other. The
removal of the turf revealed a slickenside between them. As expressed
by Prof. W. B. Rogers, who examined the locality
with us a few days later, it "looks as if the lime- 9
stone had backed up on to the green rock." These :^ I'
facts are mentioned to show our reasons for be- | |.
lieving that the Helderberg rocks on Fitch hill and i "
the neighborhood overlie the Lisbon group uncon- « |
formably. "^ ^

The order of the rocks from Fitch's house to the I f
very summit of the hill is well shown in Fig. 40. ^;:
What I have called the top of the hill thus far, sig- f ?
nifies the highest part of the cleared land. This ^ ^.
section reaches the very summit, which is wooded.
Above the Lisbon series come about fifty feet of
Lower Helderberg limestone, holding the chain
coral, Pcntavienis, and a gasteropod, with the oth-
ers mentioned by Mr, Billings. This is followed by
forty or fifty feet of coralline slate ; thirty or forty
feet of friable conglomerate, white, when weath-
ered, like the Oriskany sandstone of New York,
the quartz pebbles being of the size of kernels of Indian com. Next is a
bluish, compact feldspar, somewhat resembling siliceous limestone; then
follows considerable tough, massive hornblende rock, with no signs of
stratification, which, with the felsite, is supposed to be a repetition of
the underlying Huronian. On the very apex of the hill is a sandstone
weathering white, but gray in the interior. It dips apparently fifty de-
grees east of north. The section is about half a mile long.

Following the limestone south-west, perhaps a fourth of a mile, we

n r
3

332

STRATIGRAPHICAL GEOLOGY.

find the purest carbonate of lime yet seen. This is interrupted by chlo-
ritic rock, — to be succeeded by fossihferous slate and limestone, — which
passes west of the slate quarry and lower down
the hill, if its strike does not alter. Commenc-
ing near the fork in the road turning to the slate
quarry, there is, first, the chlorite rock on Fig. 41,
with its usual position; second, the Helderberg
rocks just mentioned. The slates predominate,
and decompose readily and unequally. High up
the hill is the gray sandstone, decomposing white,
continued from Fig. 40. The hornblende rock on
the crest of the hill is one massive stratum, with
no indication of divisional planes. The slates
were at first thought to be the continuation of
the quarry ledge on Fig. 42. Both have the py-
rites in abundance, and the same general aspect;
but, by comparing the several figures together,
it seems as if the sandstone would properly corre-
spond with the conglomerate back of the quarry ;
and the hornblende rocks agree with the green
schist. That would make the slates just men-
tioned correspond with each other, as well as the
harder dark slates in which a synclinal appears.
The latter slate is a hard, black, even-bedded rock, which also shows
itself continuously nearly to Parker brook. The east part of the syncli-
nal is wanting in Fig. 41, its supposed place being covered by the allu-
vium of the Ammonoosuc. The strike varies to the north-west near L.
A. Parker's house, at the east end of the section ; and the rock makes a
part of the zigzag arrangement before alluded to.

The next section (Fig. 42) passes from the slate quarry to the Ammo-
noosuc river, near the south line of Littleton, a mile and seven eighths
long, and seven eighths of a mile south-west from P^ig. 41. The same
hill is traversed as before, but the upper slates are better displayed. They
are covered by two grades of argillaceous sandstones, the lower portion
being more argillaceous and of a darker color; the upper grayish, and of
a different texture from the sandstones on Figs. 40 and 41. The hill

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

333

was crossed transversely as far as indicated; the eastern slope remains
unexplored. The strike varies N. 65° E. to N. 70° E. There seems to
be an outcrop of the Lisbon group dipping tow-
ard Bluberry hill in the valley east. |

The slate quarry is a location known to resi- ■§
dents, on account of extensive excavations once •<
made there. The slate is of excellent quality, -^
and, were it not for a profusion of cubical crys- | c|.
tals of pyrites, would be worth quarrying. It o p
dips about 80° south-easterly. Above it on the ?"
hill is an interesting conglomerate, with pebbles i- o
averaging the size of a hen's egg. This is what | I
we have familiarly called the "egg" conglomer- f" s
ate. The paste is the slate of the quarry. One t- -
pebble is a foot long. Siliceous fragments of a -^p
dark color predominate, which seem to have been "^ Z
derived from the Lisbon group, as also have been n ^
a few greenish chloritic bits. Others, and possi- \ ^
bly the greater portion, show resemblances to fl-
the compact feldspars of the Porphyry group. "„ f-
There are small bits of black slate like that oc- \ ^
curring near the east end of Fig 41. ^ §■

Two recent visits to the east end of the above \ \
section give the following information respecting | -^
it. Starting from S. Hastings's, Jr., in Littleton, \ %
the Huronian rocks were not seen, because cov- '^ \
ered by drift. The slates have somewhat of a 5-^
sandstone aspect, dipping north-westerly up the s w
side of the mountain. On top the layers exhibit ? |
contortion, and have a more easterly course. The \ "^
east slope is very precipitous for three hundred % «
feet; and the strike is fairly east and west, or ?
running with the section line for a considerable \

a-

distance, with vertical strata, or 80° southerly. |^
At the base of the precipice are numerous large |
Huronian loose blocks. The first ledges seen

334

STRATIGRAPHICAL GEOLOGY.

are of the same character, dipping 70° N. 52° W. Upon them are some
narrow ranges of conglomerate Hke that seen above the slate quarry.
On examining the fields back of J. K. Corey's house, we find some of
these ledges isolated, and others resting upon the Huronian, with the
same dip as the underlying strata. Next there occurs a large ledge of
Helderberg limestone, full of coralline and crinoidal remains. Some of
the limestone bunches contain irregularly shaped masses of chlorite,
evidently of later origin than Helderberg, or, more precisely, of the age
of the elevation of the fossiliferous sediment. Still farther east is a
mass of white quartz, full of reticulated veins. Then there succeed a
great many ledges of green schists, full of fragmental grains, belonging
to our Swift Water series, dipping like the fore-
going. Near J. K. Corey's house some of the
layers have the aspect of calcareous decompo-
sition. On the height of land to the south there
^: S is a great abundance of embossed schistose lay-
1 1 ers, like those near the house, dipping 75° N. 52°
1 1 W. Below Corey's house the greenish, sandy
* I schists dip 70° N. 52° W.

c s Another trip was made from the slate quarry

-2 f to Corey's farm. The conditions of Fig. 42 were

'o^ „- found up to the slate. On the ridge I found ar-

i,-| gillaceous schists, with the high north-westerly

■I ^ dip. The eastern slope is gradual, but so covered

1 1 by earth that no ledges appeared. The blocks

ffi of Huronian hornblendes and diabases suggested

- the possible presence of ledges to connect the

I Corey schists with those on the wooded summit

I of Fitch hill. North from Corey's is a spur from

-o" the main Blueberry range, running south-east-

I erly. This proved to be the same greenish, sandy

I schists with those before described, dipping to

•^, the north-west.

The next section in Fig. 43 is three and three
eighths miles long, and passes over more strata.
It begins high up the early course of Mulliken's brook, crosses Blueberry

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 335

hill, and terminates a short distance north of North Lisbon, reaching
the gneiss. At the beginning is the Lyman instead of the Lisbon group,
though the latter would appear if the section had been elongated half a
mile. Near G. D. Shute's house and "Indian Rock" these schists dip
85° N. 30° W. The east border of this group dips 80° N. 40° W. It
weathers whitish, presenting a chalky aspect at a little distance. Along
th'e carriage-road succeeding is an extensive range of Helderberg slates
and limestones, containing Favositcs. The strata stand perpendicular,
running north-east. On a tributary stream, near C. Hastings's house, is
a fine exposure of grit, slates, and calcareous beds, greatly resembling
fossiliferous strata in Maine and New York, but they yielded no relics
of life, in a half-hour's search. This series of strata forms a steep cliff
seventy or eighty feet high, which can be followed a mile and a half to
the slate quarry. The country at the base of the cliff is everywhere a
swampy forest not intersected by roads, so that its exploration is not
inviting.

Passing up the hill there are so many boulders of conglomerate, that
we must believe this to be the rock in place. Near a school-house it dips
S. 6?)° E. Its character does not vary from that seen in Fig. 42. This
view will make the fossiliferous slates correspond with the slates at the
quarry. Near the top of Blueberry hill are slates with the course N. 55°
E.; and others dip 20° south-westerly, which may be explained by sup-
posing cleavage planes to be present having a different strike from the
strata, or by a local sliding. On the crest of the hill the slates dip 70°
N. 35° W. This continues about half a mile on the line of section, or
as far as I was able to travel upon it. There is room enough for the
double thickness of slate seen in Fig. 42.

The slates extend on the eastern slope of the hill to the ridge east of
C. Ela's in Lisbon, where there is an excavation in them made for some
mining object. The greenish Huronian schists adjoin them, followed by
a hornblendic band, seen at J. Clark's, dipping north-westerly. Speci-
mens of the mica schist come next, probably the whetstone slate layer,
followed by more hornblende and the Swift Water sandstone, a rock with
whitish cement and pebbles of the size of buckshot, with vertical dip.
The locality of the last is on top of the hill, next the Ammonoosuc river.
The hornblende first spoken of is that connecting the Whipple Brook

336

STRATIGRAPHICAL GEOLOGY.

saw-mill and perhaps Fitch hill. The other strata belong to the Swift
Water division of the Huronian. There is a resemblance between the
mica schist spoken of and the rock of Eustis hill. The gneiss following
belongs to the Bethlehem group, dipping 30° northerly, and is a part of
the range mentioned upon page 274, running into Bethlehem, and termi-
nating less than two miles south-west from the section line. Whatever
may be the stratigraphical character of this group in Bethlehem, it* is
practically an inverted anticlinal at North Lisbon, since it is flanked on
both sides by newer rocks, all dipping in the same general direction, un-
less the discordance in strike of the gneiss and Huronian is of enough
consequence to be styled an unconformity.

Fig. 43, if protracted, would cross another interesting Helderberg area;
but, for the sake of clearness, I will add a small section (Fig. 44), with
greater horizontal scale, situated about a quarter of a mile to the south-
i g west, crossing the Ammonoosuc nearly at North Lisbon
"^ ;3 railroad station, and passing up its south branch. The
I Z gneiss dips 36° N, 47° W, at the lead mine. Next is a
X S coarse conglomerate, seen in the field and under the
>^ "^1 bridge, dipping 6s°-70° N. 22° W. As there is a gen-
# i J eral resemblance between this and the conglomerate of
s' I = the Lisbon group, it was not till the recent discovery of
h5 I extensive Helderberg strata that these ledges at North
I * & Lisbon appeared to belong to the Paleozoic series. The
J I 3 materials of the pebbles are white and blue quartz, hy-
" '^ ^ dro-mica schist or Lisbon group, two or three gneisses,
I I o Coos slates, and calcareous masses, with an argillo-mica-
ceous paste. Some pebbles are a foot long. They are
usually slaty, but not contorted.

Crossing the river and walking over twenty rods of gravel, we came
next to a more interesting locality in the South Branch valley. The first
ledge, back of the last house on the road, is micaceous slate, with calca-
reous layers, cut by an obscure igneous dyke. The strata dip 45° N. 32°
W. Beneath are fifty feet of coarse conglomerate, containing, in addi-
tion to the pebbles under the bridge, pieces of the mica schist of the
Coos group, without staurolite. The slates next observed have a higher
dip. They are followed by indurated slates dipping 50° N. 22° W. They

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 337

are traversed by beautiful ribbons of banded trap, from half an inch to
three inches in width, which jump and curve in a fanciful way.

The next series evidently belongs to the Lisbon group, having essen-
tially the same strike and dip with the last mentioned beds. It extends
for about twenty-five rods along the stream. The rock is a labradorite-
diorite, according to Mr. Hawes's careful determination. Probably this
is the place for a coarse hornblende aggregate or diorite rock, which is
seen on the west side of Streeter pond in situ, and in enormous boulders
between North Lisbon and the pond. These hard rocks terminate just
as the stream bends and passes through a narrow, rocky gorge of clay
slates, containing staurolite and garnet, dipping 60'' N. 2cf W. The
same dip is manifest higher up. The ledges extend for twenty-five or
thirty rods ; after which the rocks are covered with earth for a great dis-
tance. The banks are made up of boulder clay, which is undermined by
high freshets ; and the road has been torn away so many times that the
town authorities have been compelled to discontinue the carriage-road,
thus necessitating pedestrian explorations in this interesting spot. A
slate similar to that just described crops out on the new road from the
station to Streeter pond, about a mile north-easterly. The course is
nearly east and west, and the strata are more nearly vertical; but the
ledges must be continuous between these points. It is shown, also, by
the presence of enormous blocks of diorite, whose source must be to the
north of the slates, and not far distant. The map shows the distribution
of all the parts of this section. The width of the coarse conglomerates
is about forty rods, which implies a thickness of at least five hundred
feet. The clay slates correspond perfectly to portions of the Coos group
in the Lyme and Lisbon sections, as well as to the interesting staurolite
slate seen at Purple's quarry in Bernardston, Mass., described by Prof.
Dana.*

When I first made this section (Fig. 44) I believed the coarse ''o-g^'^
conglomerate of Blueberry mountain and the accompanying sandstones
and slates belonged to the Helderberg. Hence the discovery of isolated
beds at North Lisbon led to the supposition of the existence of a Helder-
berg area there. The chief evidence of this Helderberg age, however, I

* Amer. your. Sci., Ill, vol. vi, p. 348.
VOL. IT. 43

338 STRATIGRAPHICAL GEOLOGY.

have not stated. The vacant space in Fig. 44, between 2 and 3, is on the
line of strike of a Hmestone containing Helderberg crinoids. Therefore
the rocks associated with it are to be regarded as of the same age. The
readier decomposition of the Hmestone has left the space vacant on the
section, being covered by a thick deposit of gravel. It is now an unan-
swered question whether these conglomerates are to be ranked with the
adjacent fossiliferous limestones, or with the coarser conglomerates asso-
ciated with the Cambrian slates. In the absence of definite knowledge, I
shall consider these conglomerates at North Lisbon as Helderberg, and
the other as probably Cambrian. It must not be forgotten that there are
sandstones and fine-grained conglomerates on the west side of the Blue-
berry Hill range readily referable to the Helderberg. Such are those on
Fitch hill, near C. Hastings's, Littleton, and numerous loose blocks scat-
tered along the unfrequented road back of Bald hill in the north-west
corner of Lisbon,

I have a little further information about the Helderberg limestones
below North Lisbon, At D. Richardson's house, and in the river bank
adjacent, are several ledges of white limestone, some of them quite pure
carbonate of lime, standing nearly vertical. About one hundred rods be-
low, or nearly opposite J. Dexter's, 2d, the limestone appears on the same
side of the river, holding fragments of the large crinoids characterizing
this formation, both at Littleton and Bernardston, Mass. The limestone
is here only twenty-five feet wide, traversed by veins of pyrites and quartz.
Bunches and large masses of hornblende are associated with it in such a
way as to suggest the possibiHty of their belonging to the underlying
floor, as the Helderberg limestones and accompanying mica schists have
been subjected to a violent pressure. Nearly opposite are similar slates
and limestones at the water's edge, dipping 75° N. 22° W, Lastly, there
are calcareous beds exposed a short distance above the turn of the car-
riage-road up Whipple brook, dipping 75° N, 42° W, All these ledges,
of unquestionable Helderberg age, may be embraced in an area of a mile
and a quarter in length, and having a thickness of strata rudely estimated
at five hundred feet.

It is a matter of interest to know whether the Helderberg rocks could
not be traced continuously from Fitch hill south-westerly along the west-
ern border of the Cambrian in Lyman. We have on this line of expos-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 339

ure an area of slates and limestones, the latter very scanty in amount,
upon the top of the hill east of the Reduction Works Company's mine,
near the house of D. Knapp. The limestone contains many small cri-
noidal fragments. The slate is friable, dipping 75° north-westerly, and
is eight hundred feet wide. This area has been preserved from denuda-
tion by the presence on the exposed side of a thick mass of conglomerate,
described upon page 305. On passing northerly the slates expand so as
to adjoin the conglomerate above the fault, and seem to extend nearly to
Young's pond. In this area are several veins of white cavernous quartz,
full of iron rust, which have been opened to a slight extent for gold,
though evidence that gold is present is meagre. It occurred to me,
when examining them, that these Helderberg veins might be distin-
guished from the Cambrian auriferous quartz by a very fetid odor and
the absence of ankerite. The very cavernous feature would hardly be
distinctive, since it may have arisen from a more perfect atmospheric
disintegration. North of Young's pond are some irregular slates, which
may perhaps represent the Helderberg.

Still another possible locality of this formation exists about half a mile
from Mill brook in Lisbon, on the road running south-west from a saw-
mill. Loose blocks of crinoidal limestones were seen adjacent to an out-
crop of the auriferous conglomerate, which seem to have been derived
from a ledge. Without doubt other similar patches will be found in dif-
ferent parts of the Ammonoosuc gold field after further search.

In my article upon the Helderberg of New Hampshire, published in
the American Jotirnal of Science, I remarked upon the probability that
the Dalton Mountain slates are of Helderberg age. Much of the rock
there is a fine argillaceous sandstone. Since the later reference of the
argillaceous rocks of Blueberry hill to the Cambrian area, this opinion is
greatly weakened. The possibility of the Helderberg slates back of the
Crawford house is set aside by further investigation.

Fossils. We have found quite a number of fossils. The circumstances
of their original discovery have been noted in Volume I, page 48. Two
parcels of these organisms were forwarded to the late distinguished pale-
ontologist of Canada, E. Billings, who had special familiarity with the
fossils of about this period in the extension of the series northward. At
first he found Favosites basaltica and a ZaphrentiSy with small crinoidal

340 STRATIGRAPHICAL GEOLOGY.

fragments. There was nothing in them that would enable us to localize
the horizon more definitely than the general term of Helderberg, which
is partly Upper Silurian and partly Lower Devonian ; but the fact of the
existence of the upper part of the series only at Lake Memphremagog,
fifty-five miles distant, led to the opinion that the newly-discovered area
was of the same age. Of the second parcel sent, from Fitch hill, Mr.
Billings wrote as follows:

"The fossils came last night. They are Favositcs Gothlandica, a large
crinoidal column, a Peutamerns closely allied to if not identical with P.
Knightii, and a gasteropod. The first two prove nothing. The Pentam-
erus goes far to show that the rock is about the top of the Upper Silu-
rian— say Lower Helderberg. The gasteropod is just like some that
occur in the same horizon. I do not consider the fossils sufficient to
decide the age of the rock very closely, but only that it is either Upper
Silurian or Lower Devonian. I have specimens of the Bernardston en-
crinites, and will endeavor to determine whether they are identical with
yours or not."

Since then we have obtained large masses of the chain coral, Haly-
sites, and probably fragments of the tribolite Lichas. This last discovery
seems to be sufficient, coupled with the presence of the Paitavierus, to
identify our New Hampshire deposits with the Lower instead of the
Upper Helderberg, The chain coral has been considered characteristic
of the Niagara limestone, a formation lower than the Helderberg. Its
extreme range is from the Trenton to the Lower Helderberg, culminat-
ing in the Niagara. Possibly we shall be able to search further for fossils
in our Helderberg and other fossiliferous strata, and thus obtain material
for a chapter upon paleontology. In that case there may be presented
hereafter full descriptions and figures of the genera enumerated above.

Relations of the New Hampshire and MassacJuisctts Helderberg. An
allied rock has long been known at Bernardston, Mass. It was first de-
scribed by my father in the Massachusetts report of 1833, with a draw-
ing of the crinoidal stems. Quite recently Prof. Dana has described the
locality and the adjacent strata,* deducing important generalizations from
his observations. The Memphremagog and Bernardston deposits lie on
the opposite sides of the same formation, — the calciferous mica schist

* Avier. Jour. Set., Ill, vol. vi, p.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT, 34I

group of the Vermont report, and Upper Silurian (supposed Niagara) of
Sir W. E. Logan's report, — and separated by a distance of one hundred
and sixty-five miles. The mica schist is probably an older formation
than the Helderberg, lying in a trough of clay slates, the latter consti-
tuting the floor of the fossiliferous beds. These slates may be Cambrian,
judging from general considerations. No fossils yet appear in them.
The calcareous schists carry a few obscure crinoidal fragments at Derby,
Vt., which are of no value in the identification of strata.

At first sight, one would declare that there is no similarity between
the Littleton and Bernardston rocks. After considerable study of both
localities, I find a few points of resemblance, perhaps as much as we
have a right to expect in synchronous deposits more than a hundred
miles apart. In our studies we often look for exact resemblances in re-
mote localities. Perhaps it is better that the connecting tie be discov-
ered with difificulty, in which case the conclusions may be more surely
established. The surroundings at Littleton are different from those at
Bernardston. The series rests on diorites and diabases, close by gneiss
and argillitic quartzites at Littleton. At Bernardston, the underlying as
well as the overlying rock is quartzite ; and in the neighborhood are the
mica and staurolite schists denominated in my report as the "Coos
group." Prof. Dana thinks it clear that the Massachusetts Helderberg
and the Coos group, as defined by me in reports of 1869 and 1870, are,
"if correctly traced out," identical.

Inasmuch as the limestones in all these localities are characterized by
a similar large crinoid, those at Bernardston and North Lisbon contain-
ing no other form whatever, and occur in the same open valley of the
Connecticut, it is presumable they are of the same age, and that is the
Silurian Helderberg, as made known by the presence of Halysites and
Pentaincnts. The opinion of Prof. James Hall, to the effect that the
crinoids in the Bernardston limestone are like those of the Onondaga or
Upper Helderberg limestone of New York, has been quoted.* Since
that time I understand that similar fossils have been found much lower
down, so that they were not necessarily confined to the Onondaga. The
correlation of the Massachusetts and New Hampshire limestones is bet-
ter, using the same fossil for our guide, since the localities are contiguous

* Proc. Avter. Ass. Adv. Sci., vol. vi, p. 300,

342 STRATIGRAPHICAL GEOLOGY.

to each other, and situated in the same ancient valley of depression.
The animals, when living, occupied the same arm of the sea, and were
separated from New York by the long Green Mountain ridge.

Extent of the Helderberg Sea. The many localities of Helderberg
rocks scattered over the middle Atlantic region indicate the presence
of the ocean in very many parts of it. At Littleton some of these rocks
now rise at least 1800 feet above tide- water. If the region rose and sank
in close correspondence with its present surface, it would be compara-
tively easy to map out the limits of the land and water. The impression
gains upon me that this depression occupied certain great valleys, leav-
ing, as hills between, the areas that are now in many places lower than
the uplifted Helderberg. The Connecticut would have been one of these
areas of submergence, the Memphremagog a second, nearly parallel, sup-
posing that the first named followed the course of the Upper Ammo-
noosuc and the Androscoggin lakes into Maine. Littleton village must
have been at least 2000 feet lower than now. The low region of the
Merrimack basin has not yet afforded any evidence of a Helderberg sub-
mergence. More likely it constituted an elevated island at the time of
the growth of the Grafton county coral reefs.

Until recently I had supposed the Blueberry mountain range consisted
of rocks even newer than the Silurian, anticipating future paleontological
discoveries of Devonian life. For reasons given above, it is probable
that these slates, sandstones, and conglomerates should be placed with
the Cambrian, a much older formation. That mountain range may have
been a submarine ridge, with the coralline growth upon both sides, as is
proved by the occurrence of the fossiliferous structures along the two
diverging lines. There is a very marked want of conformity between
the coralline and Huronian layers, while there is not so much difference
between the Helderberg and Cambrian. The former, closely pressing
the latter, would naturally exhibit the same line of strike; and the near
verticality and inversion of the strata, the force of elevation having been
greater in some areas than others, render it difficult to distinguish an
unconformability through the dip.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

343

Catalogue of the AmjMonoosuc Collection.

The same general remarks will apply to this catalogue and the accom-
panying maps, that have been made heretofore respecting the similar
illustrations descriptive of the Coos and White Mountain areas. In par-
ticular, it may be said that these numbers appear on two distinct maps,
the one of the entire field, and of the limited area in Lyman specially
surveyed with reference to the mining interests. A few of these num-
bers have been placed upon Plate XII.

PORPHYRITIC GNEISS.
Bethlehem.
I, Porphyritic gneiss.

Littleton.
2-7, Porphyritic gneiss.

BETHLEHEM GNEISS.

Lisbon.

17-20, 22, Gneiss, with much black mica.

Littleton.
21, Gneiss, with much black mica.
22 a, Gneiss, sHghtly epidotic.

ATLANTIC GNEISS.
Littleton.
8-11, 13-16, Gneiss.
9 a, Diorite dyke in 9.
12, Hornblende schist.

Lisbon.
25, 46, Hornblende rock.
26-28, 30, 32, 33, 40-42, 44, Limestone.
29, 45 a, 45 b, Mica schist.
31, 34, 35, 55, Calcareous schists.
36, Conglomerate.
37-39, Gneiss.

43, Junction of limestone and granite.
45, Magnetite.

45 c, Ferruginous mica schist.
47, Hornblende and chlorite.
54, Trap.

Landaff.

48, Gneiss, with garnets.

49, Mica schist.
50-53, 56, Gneiss.

57, Granitic gneiss.

LISBON GROUP.
Littleton.
59-65, 67, 68, Green schists.
66, 72, Ti, Sandstones.
69, 70, 75, ']•], Diabase.
71, 74, 76, 78-81, Green schists.

82, Hornblende dyke.

83, Galena and copper pyrites.

84, Gossan — Albee mine.

85, Talcose gangue of copper vein.
86-89, Greenstones.

89 a, 89 c, 89 e, f, g, Argillitic mica schists.

89b, Diorite.

89 d. Green schist.

89 h, Protogene.

891, Mica schist.

868, Compact feldspar.

869, Hornblende schist.

Lisbon.
23, 24, 90, 91, 96, Hornblende schist.

58, 99, g-i, 1, 622, Quartzite.
92-95, Labradorite diorite.

97, 99, 99b-d, 99 n, Dioritic schists.
99 a, Iron ore nodule.

344

STRATIGRAPHICAL GEOLOGY.

99 6, f, j, m, Hornblende schist.
99 k, Gray micaceous conglomerate.

Section from Bronson's Quarry to
Dodge Gold Mine (Fig. 28). Nos.
100-141.

Gneiss.
TOO, Limestone — Bronson's quarry,
loi, Trap.

102, Staurolite gneiss.

103, Hornblende rock.

Coos Group.
104-106, Staurolite mica schists — Mink

pond.
107-108, Staurolite slates.
109, Garnetiferous slate,
no. Slate, with staurolite and garnet.

111, Garnetiferous slate.

112, Pyritiferous slate.

113, 114, Garnetiferous slates.

Swift Water Series.

115, Slate — Atwood gold mine.

116, Quartzite.

117, Sandstone, with white cement.

118, Actinolite schist. S. M.

119, Hornblende schist.

120, White mica schist.

121, 122, Sandstones.

123, 124, Hornblende schists.

125, Argillo-mica slate — railroad crossing
at Lisbon village.

Lisbo7i Group.

126, 127, Light-colored hydro-mica schist.

128, Conglomerate.

129, Hydro-mica schist.

130, Diorite schist.

131, Diorite schist— decomposing.

132, Galenite in schist.

134, Diorite schist.

135, Gray schist.

136, Quartz, near J. Titus's house.

Lyman Croup.
^37i Argillitic mica schist.

Cainbrian.

138, Clay slate.

139, Quartz vein.

140, Clay slate — Dodge mine.

Lyinau Group.

141, Argillitic mica schist, back of mine.

South-east Corner of Lyman.
142-147, 149, Protogene.
148, Hornblende rock.

Range passing Gordon''s house.
150-152, Argillaceous sandstone.
153-155, Diorite schists.
156, Hornblende schist.
157-163, 165, Green schists.
164, 623, Quartz vein.
590, Conglomerate.

Parker Hill Range.
166-171, 173-180, Green schists.
172, Light-colored schist.
181-184, 189, 190, 248, 278, Green schists.
185-188, Argillaceous schists.
563, Conglomerate.

Landaff.
939, 940, Chlorite schist.

LYMAN GROUP.
Lyman.
191-212, Dolomites.

Littleton.
213-216, 218, 220-222, i-2\--ii\, 849, 850,

852, Argillitic quartzites.
217, 223, Slates.

Landaff.

235, Argillitic quartzite.

236, Slate.

237, 238, Quartz veins.

Bath.
239-242, 245-247, Argillitic quartzites.

243, Dolomite.

244, Copper vein.

Lyman.
249-264, 266-268, 270-273, 275-278, 282,
283, Argillitic quartzite.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

345

265, Quartz vein.

269, 274, 279, 281, Slaty layers.

RAXGE FKOM J— 6 TO NEAR B — 12.

2S6, 287, 293, 294, 297, Green schists.
288-292, 295, 296, Argillitic quartzites.

Main Range — Divided into small

Areas.
Between Lines U and V, east of i i .

298, 301, 302, 304-307, 309-318, 320-322,
Argillitic quartzite.

299, 300, Slaty layers.
303, Greenish schist.
308, Ferruginous slate.
319, Femiginous sandstone.

Between Lines S and T.
3-3-333^ Argillitic quartzite.

334, Slate.

Between S and R.

335, Conglomerate, argillitic quartzite peb-
bles in argillaceous paste.

336-339, 342-346, Argillitic quartzite.
340, 341, Dolomitic slate.

Between Lines R and O.
347, 348, 350-361, 363-376, Argillitic

quartzite.
349, Conglomerate like 335.
362, Quartz vein.

Between N and M.
377, 380-390, Argillitic quartzite.
378> 379, Greenish schist.

Between M and L.

391-395, 398-400, 402, 404, 406-416, 418-

421, 423-431, Argillitic quartzite.

396, 405, Argillitic quartzite — ferruginous.

397, 401, 432, Grayish schist.
403, Slate.

417, Grit, with ferruginous spots.

West of Line ii and East of Aurif-
erous Conglomerate Ranges.
Between V and O.

433, 436, Greenish schists.
VOL. IL 44

434. 435, 437, 43^"^, 444-447. 449-457, 459.
460, Argillitic quartzites.

439, 458, Quartz vein.

440, 441, 448, Slate.
442, 443, Dolomitic slate.

Between O and L.

461, 463, 464, 465-474, 476-4S6, 488-493,
Argillitic quartzite.

462, 475, 487, Schists somewhat ferrugi-
nous.

Between L and G.

494-499, 501-506, 508, 509, 512-523, Ar-
gillitic quartzite.

500, Quartz vein.

507, Schist, with calcareous incrustation.

510, 511, Schists — ferruginous.

524, Dolomitic slate.
West of Conglomerate Ranges.

525-529. 536, 539. Slates.

530-533. 535. 538. 540-544. 546, 547. Ar-
gillitic quartzite.

534. 537. Dolomite.

545, Greenish schist, with ferruginous
spots.
Miscellaneous Localities.

548, 550-554, 557-561, Argillitic quartzite.

549, Dolomite.

555, Drab conglomerate.

556, 562, Shale.

Other Localities in Lyman.
564, "Stevens's fertilizer."
565,567-570, 573-575. 577. Argillitic

cjuartzites.
566, 571, Dolomite.
572, 576, Conglomerate.

Narrow Bands of Slate inclosed in
Lyman Group.

578-588, Slate.

589, Argillitic quartzite.

346

STRATIGRAPHICAL GEOLOGY,

AURIFEROUS CONGLOMERATE.

LyiJian.

591-594, 596-603, 605-609, 614, 617-620,

Conglomerate of quartz pebbles.
595, 604, 615, Conglomerate containing

greenish pebbles.
610-613, Pebbles from conglomerate.
616, Conglomerate, with greenish layers.

Bath.
621, Conglomerate, with chlorite.
CAMBRIAN.
Lyman. South-east Range.
624-626, 628, 630, Clay slate.
627, 629, Quartz veins.

Fragmentary masses, possibly beds in the
Lytnan Group.

631-639, Clay slate.

Maiji Range.
640-662, 669-691, Clay slate.

663, Pyritiferous slate.

664, 665, Auriferous quartz.

666, Quartz, with pyrites.

667, 668, Quartz, with ankerite.

Bedell Branch— West.
692-722, Clay slate.

Bedell Branch — East.
7^3—7^7, Clay slate.

Area north of J. Williams'^ s.
738-750, Friable clay slate.
Areas in north-west part of special map.
751-764, Clay slate.

Beds in Lymatt Cronp.
765-768, Argillaceous schist.

Littleton.
769-771, Clay slate.

854, 855, 8553, 856, Argillaceous schists.
85 1) 853> Sandstones.
872-874, 877 b, 877 f, 878-882, Clay slate.
873 a, 876, 877 c, 877 d, Argillaceous sand-
stones.

875, 877 a, 877 e, Argillaceous schists.
877 g, 883-892, 892 a, Conglomerates.

Lisbon.
772, Bent slate.
772 a-b, 772 e-f, 772 h-k, 916, 917, Clay

slate.
772 c, 772 1-m, Sandy slates.
772 d, Quartz.
772 g. Trap — loose.
772 h. Large pebble from conglomerate.

Lyman.
772)^ 916, Clay slates.

Bath.
774, Schist in slate.
77S^ 777, Clay slate.
776, 778-781, Quartz veins.
782, Galena.

COOS GROUP.
Lisbon.
783-788, Quartzite.

Landaff.
789-799, Quartzite.
941, Mica schist.

Littleton.
800, 8or, 804-811, 812 a, 812 b, Mica
schist.

802, 812, Staurolite mica schist.

803, Hornblende schist.

Lisbon.

813, Whetstone mica schist.

814, 815, 821-823, 832, 835, 836, 816, 819,
837, Garnetiferous slate.

817, 820, 824, 825, 831, 833, 834, Stauro-
lite schist.

818, Clay slate.
826-829, Trap.

830, Hornblende rock.

HELDERBERG.
Littleton Buhrstone and (2iiartzite.
838, 840-848, Buhrstone.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT.

347

839, 839 a-c, Sandstone.

Littletoti Limestone.
857, " Horse" in limestone.
858-865, 865 a, Limestone.
865 b, Chlorite in limestone.
Other Rocks.

866, Conglomerate.

867, 871, Sandstone.

North Lisbon Series of Rocks.

893, 898, 902, 914, Limestone.

894, 895, 897, Mica schist.

896, 903-907, 909-913, Conglomerate.

899, 901, 908, Slates.

900, Calcareous mica and hornblende
schist.

900 a, Argillaceous mica schist.

900 b, Conglomerate.

900 c, Mica schist in 900 b.

good, Ouartzite.

915, Siliceous dyke.

Specimens between D. S. Richard-
son's AND D. Richardson's.

915a, Micaceous quartzite. D. S. Rich-
ardson's.

915 b, Mica and hornblende schist. Near
D. S. Richardson's.

915 c, White limestone. Between D. S.
Richardson's and J. Dexter's, Jr.

915 d. Micaceous quartzite. Same as the
above.

9156, Conglomerate. Same as the above.

915 f, Quartz vein. D. Richardson's.

915 g, White limestone. D. Richardson's.

915 h, Gray micaceous limestone. D. Rich-
ardson's.

Lisbon.
9151, Sandstone — loose.
915 j-k. Limestone.

Lyman.

917, Slate.

918, 919, Ouartzite.
920, 921, Limestone.

SWIFT WATER SERIES (^Huronian).

Section from a Bridge above Swift

Water to near Starch-Mill (Fig.

923, Micaceous quartzite.

924, Decomposing quartzite.

925, Glossy mica schist.

926, 927, Hornblende schist.
928, 929, Mica schist.

930, Micaceous quartzite.

931, 932, Mica schist.

933, Chlorite schist.

934, Gneiss.

935, Slate.

976, Micaceous conglomerate — at starch-
mill.

Lisbon.

937, Conglomerate.

938, Slate.

Landaff.
942, 943, 947, 954-956, Micaceous quartz.
944, 945, Quartzite.
946, Mica schist, with acicular hornblende.

948, 953, Chlorite schist.

949, 951, 952-960, Mica schist.

950, Slate.

952, 962, Hornblende schist.
961, Mica schist conglomerates.

34-8 STRATIGRAPIIICAL GEOLOGY,

THE CONNECTICUT VALLEY BETWEEN HAVERHILL AND CLAREMONT.

The second section of the Connecticut valley occupies the country
between the north part of Haverhill and Claremont, the limits being de-
signed to cover the territory south of the Ammonoosuc gold field as far
as to include the rocks of Mt. Ascutney, The following are the rock
formations in this area, arranged in the supposed order of their age: i,
Bethlehem gneiss; 2, Huronian, with three or four subdivisions; 3, Cam-
brian clay slate; 4, Coos quartzite; 5, Coos slates and schists; 6, Calcif-
erous mica schist; 7, Eruptive granites, including the Mt. Ascutney area,
which is partly composed of rocks older than Huronian. This territory
is about fifty-eight miles long and fifteen wide, including all of Vermont
that appears upon the map. That which lies in New Hampshire is
usually five or six miles wide.

Bethlehem Gneiss.

Regarding the narrow quartzite areas as the eastern border of our field,
it is clear that we have three isolated fields of Bethlehem gneiss on the
east side of the Connecticut, and perhaps the representative of another
among the foundations of the Ascutney formations. First, is the one in
Haverhill ; second, in Orford and Lyme ; third, in Hanover and Lebanon.
These all have certain features in common, and each has its peculiarities.
They are all repeated east of the quartzite areas in the Merrimack dis-
trict.

HavcrJiill Area. This is confined to the town of Haverhill, with a
length of about eight miles and a width of three. Three sections cross-
ing it are represented. (Fig. 45 to Fig. 47.) In the most northern
there appear to be an anticlinal and a synclinal ; in the second, nearly
vertical strata throughout, which may therefore include one or more in-
verted axes ; and in the third, a synclinal. We have noted the following
varieties of rock in this area: Protogene; common gneiss; the same, with
an excess of black mica; granitic beds; hornblende schist; soapstone;
and limestone. The first ledges of gneiss seen south-east from Woods-
ville are inclined 40° N. 82° W. at a less angle than those farther east, as
at the soapstone quarry, dipping as much as 75° north-westerly. The
soapstone is from twelve to fifteen feet wide, with some pyrites scattered

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 349

through it. The rock south from the quarry is quite granitic. The
strike runs about east and west, changing abruptly from the north-east
curve in a quarter of a mile. There is a large quarry of granite at H.
Eastman's, about a mile north-easterly from North Haverhill, with other
smaller openings in the neighborhood, and a similar stone upon the high
hill-top north of French pond. By F. C. Handford's the granitic blocks
are so numerous as to suggest the close proximity of the ledge. Other
exposures of gneiss, dipping 70° north-easterly, appear at the south-east
of a hamlet north of North Haverhill. The enormous area of alluvium
along the valley of Demming Pond brook conceals the ledges over much
of this formation.

On the road from North Haverhill to Swift Water Village are other
interesting gneissic outcrops. Hornblende schist and protogene gneiss,
dipping 65° S. 43° W., occur by W. C. Marston's and a school-house. By
R. M. Sly's, half a mile from the town line, we find ordinary gneiss dip-
ping 6S° S. 77° E. There are important irregularities in the course of
the strata, in the north part of Haverhill, not yet worked out. Close to
the Bath line, on the road passing French pond, the dip is 40° N. 72° W.
I observed along this road, also, a considerable hornblende schist. There
is protogene on the east side of Brier hill. There is an extension of the
Swift Water division of the Huronian, nearly as far as French pond, of
at least a mile and a half width along the town line, and a smaller pro-
jection up the valley of the tributary streams to the west. Between
these projections is a similar point of gneiss, to which allusion has been
made heretofore, as it seems to underlie the Swift Water rocks (Fig. 35).
It is the north-easterly continuation of the Brier Hill range.

Another region of interest is afforded by the limestone and its sur-
roundings. There are numerous ledges of the gneiss, holding an excess
of black mica, on the road from Swift Water to the limestone quarry.
By E. Header's the dip is N. 26° E.; by H. & H. S. Carr's, and to the
south, the dip is about 70° N. 60° W.; by M. Mann's the dip is 70° N.
50° W. By S. Hartwell's the gneiss dips 85° N. 34° W., and the layers
seem to run to Black mountain in the north part of Benton. The lime-
stone dips N. 20° W. as much as 70° W. Of this rock there is an im-
mense supply. It occupies the valley of the north branch of Oliverian
brook, and may be several hundred feet wide. We have been unable to

350 STRATIGRAPHICAL GEOLOGY.

explore it, but it may be followed north-easterly a considerable distance.
It has been quarried largely here (at Mason's) for burning. It should
also extend westerly. South of the quartz towards East Haverhill the
gneiss dips 40° N. 20° E. The limestone crops out near the quartzite,
but is connected unmistakably with the gneiss. On Knight's hill the
gneiss dips 70° N. 30° W., holding a large trap dyke. The high land to
the south-west of Knight's is probably composed of a later formation,
overlying the gneiss unconformably. The village of East Haverhill lies
upon a drift plain. Many large blocks are of gneiss, so as to give one
the impression at first that this rock underlies the village, especially as
it constitutes Iron Ore hill to the south. An outcrop of the Bethlehem
gneiss by J. Blake's, a mile and a half north of the railroad station, has
the dip of 40° N. 32° W. Between this and the limestone quarry is the
westerly extension of the Sugar Loaf Mountain quartzite. The latter
may form a synclinal resting upon the gneiss. Sugar Loaf showing strata
dipping south, and Hogsback mountain having the north dip of the quart-
zite. The gneiss crops out upon Blueberry and Owl's Head mountains
in Benton; but I have no data to show whether the synclinal structure
pertains to the lower as well as the upper series in that town. There is
evidence of its existence in the east part of Haverhill, as shown in Fig.
47. Gneiss exists near Haverhill town-house and in the valley of Cold
Spring brook, but I have no facts to present in reference to its position.

As the conclusion to be drawn from these statements, we have, first,
the anticlinal ridge from North Haverhill village to Swift Water, flanked
westerly by obscure Huronian rocks at one time thought to represent the
Montalban scries ; second, an anticlinal line from near Knight's hill north-
easterly ; third, there is the synclinal between these anticlinals; and,
fourth, the more important basin underlying the Sugar Loaf quartzite.
These axial lines all have a general north-easterly course. I have not
described the whole of this area, as a portion of it passes out of the Con-
necticut into the Merrimack district, and it will be alluded to again in a
subsequent chapter.

The Orford-Lyme Area. This extends from near Indian pond in the
north part of Orford, to include l^ear hill in the south part of Lyme, a
distance of ten miles. It may possibly represent the continuation of the
Haverhill area, the intervening space of about ten miles being covered

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 35 1

by Cods rocks. The i)rcdominant varieties of rock arc the same here as
before, the limestone occurring in a longer range, and the protogene ex-
isting in larger amount. Pine hill may be the north end of the outcrop
of this formation. It appears along the road over its northern flank. On
the north and south road, west of Pine hill, none of these ledges occur
north of the North Branch. Just to the south of this stream is a great
profusion of its boulders, suggestive of accumulation by glacial agency.
East of Sunday mountain, at the fork in the road, and by J. and A. Mars-
ton's, half a mile east, the protogene gneiss dips 80° N. 42° W. South
of L. Hancock's and the blacksmith's shop, the same rock dips the same
way. On the road north-east from J. Howard's the ledges are concealed
mostly, but it occurs both west, at J. M. Learned's, and east, at Mrs. R.
Hall's. On the north slope of Cuba mountain a hornblendic variety
crops out three or four hundred feet above the road, dipping 85° S. 17°
E. The rock seems to form a floor, on which the slates and quartzites
of Cuba rest, the latter series being probably isolated, so that in "Davis-
town" this area of gneiss connects directly with that of Wentworth and
Warren.

There is a large development of protogene in the valley of Jacob's
brook. On the north side, near its western limit, it dips 80° N. 54° W.
The dip is essentially the same at its eastern limit. On the south side
of this brook, at the north base of Bass hill, a north-easterly dip of 85° is
recorded. The same rock extends to the summit of Bass hill, where it
holds a vein of quartz, with titanic iron and massive hornblende crystals.
East of A. English's, near the south Orford line, the dip is 70° N. 62° W.
On the same line, east of Lime hill, the dip is 60° N, 54° W., and half a
mile west, on the east side of Davison hill, the dip is 15° east. The hill
is composed entirely of the same material.

An interesting feature of this area is the occurrence of a long line of
limestone. We have it first at the west base of Cuba mountain, near B.
Sanders's ; then it appears towards Lime hill. Just in Lyme, by D. F.
Tillotson's, it dips 40° N. 74° W.; at J. Smith's it dips 50° westerly. At
the fork of the road from Lyme turning to Dorchester and Canaan, there
is a long exposure of limestone dipping 60° N. 82° W. As one follows
the Canaan road, the limestone shows for a considerable distance. This
limestone can be traced continuously, therefore, for a distance of about

352 STRATIGRAPHICAL GEOLOGY.

eight miles. In my second annual report I ranked this layer with the
Coos group, as well as the band of Bethlehem gneiss accompanying it to
the west. That reference is an error. The gneiss here is obviously the
rising up of an older formation in the midst of slaty rocks, separating the
mica schists from the quartzite believed to be of the same series, since
they are not separated from each other farther south.

West of Post pond in Lyme this gneiss crops out, dipping N. 52° W.
To the south, along Grant brook, the outcrops constitute massive bosses,
rounded by ice, in which I find it difficult to identify the planes of depo-
sition. I suppose they must agree essentially with the inclination of
the slates to the west, and the limestones to the east. At A. B. Dim-
ick's, near the western border, I have an observation of a dip in it of 25°
N. 50° W. By I. P. Stark's the dip is 30° N. 17° W. Hornblendic and
epidotic varieties occur half a mile south of Stark's, on another road, dip-
ping 15° N. 28° E. This is probably a local irregularity in the position.
Near J. P. Dimick's, at the north foot of Bear hill, the recorded observa-
tion indicates the position of 20° N. 24° W. Along the Canaan road,
between Bear and Holt's hills, are fine exposures of gneiss. Bear hill
rises precipitously on the west for two or three hundred feet. It is prob-
ably composed of gneiss at the base and quartzite at the summit, both
with a very low north-westerly inclination. There should be further de-
tails of the position and character of these rocks in the south-east part
of Lyme, in the following chapter. The south end of Bear hill is precipi-
tous ; and the gneiss terminates as abruptly as the hill.

The dip of this gneissic area seems to be essentially monoclinal, with
slight indications of a synclinal under Mt. Cuba, and at the east base of
Davison hill. The structure will probably prove to be like that of the
Hanover area, which has been examined with greater care. Some fur-
ther light as to its relations to the adjoining rocks will be gained by re-
ferring to the several sections crossing the rocks in Orford and Lyme
(Figs. 50-54)-

The Hanover-Lebanoii Area. This extends from the north part of
Hanover to the south part of Lebanon, about ten miles long and three
miles wide at its maximum. The north end is narrow, commencing in
Woodward's and Spencer hills, rising into Lord's and Prospect or Pinnco
hills, which are the culmination of the range as respects height ; it con-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 353

tinues into Corey hill, is cut deeply by the valley of Mink brook, but
rises into large hills in the north part of Lebanon. These are again cut
by the Mascomy river; and the country rises into considerable eminences,
but falls off before terminating in the south part of the town. As rocks,
we have, first, the typical variety of protogene ; second, common gneiss,
or that which contains a considerable black mica ; third, schists, consid-
erably ferruginous, passing into mica schists ; fourth, quartz beds ; fifth,
hornblende schist, at the borders, which may belong to the Huronian
system. The most northern of the hills referred to this series is deeply
covered by drift, with a strongly ferruginous soil. Next, the Spencer
hill has ledges of gritty pyritiferous mica schist. About L. Hall's the
rock is similar, dipping as much as 55° N. W. South of O. Pinneo's we
have a mixture of ferruginous, micaceous, and gneissic strata, dipping
45°-50° N. 32° W. With them is a quartz bed ten or twelve feet wide,
extending for several rods. About on the top of Prospect hill the rocks
are similar, dipping 20° N. 26° E. They are the same on the summit.
North of Lord's hill, where a road turns to O. Pinneo's and to the south,
are ledges of micaceous and ferruginous rocks dipping 50° N. At J. C.
Child's the same schists, less siliceous, dip 50° N. W. At H. S. Davis's
there is gneiss dipping 65° N. 32° W. Lord's hill is composed appar-
ently of the same materials with Prospect. Perhaps the schists as far
south as the bases of Prospect and Lord's hills should not be ranked
with the Bethlehem. I put them here provisionally, chiefly to render
unnecessary the making of another division of the strata.

The unequivocal strata show themselves to the south of these high
hills. At A. Wright's the gneiss dips N. 13° E.; at J. J. Mason's the
dip is 25° N. 2° W., with a band of white quartz twelve or fifteen feet
wide, and like that mentioned on the north side of Prospect hill. The
ledges on the south side of the last-named hill are numerous, dipping 20°
northerly. It is 18° N. 12° W. at T. W. Durkee's. By C. C. Foster's
the dip of gneiss is 30° north-westerly. The gneiss may be followed a
short distance down the ravine towards C. Houston's till it adjoins horn-
blende schist, dipping in the same general direction. Near W. Hall's, on
top of Balch hill, is a gneiss dipping 20° N. ^,7° W. The rock contains
a large part of black mica, and this seems to characterize all the layers
on the west side of the area, others occurring in Lebanon. The same is
VOL. II. 45

354 STRATIGRAPHICAL GEOLOGY.

true of the broader eastern belt at J. Hough's and at Mill Village. At
the former place hornblende is present, the strata inclining 75° N. 55° E.
The following is the order of rocks from west to east across this mica-
ceous band along Mink brook and through Mill Village: Mica schist,
near Hon. I. Ross's, on road turning to Lebanon, dipping 65° easterly;
schist, 65° E.; decomposing mica schist, 45° N. 6^)° E.; epidotic mica
schist or gneiss at Mill Village store, 65° N. 30° E. There is an abun-
dance of similar ledges to the Baptist church. East, the same rocks ex-
tend about a quarter of a mile. A few rods north of the church there is
a massive micaceous schist, resembling hornblende rock. A real horn-
blende schist by Mrs. Kinne's, about a mile north, dips 80° N. 70° E.
On the hill east of Mill Village there are light-colored soft schists, show-
ing the presence of pyrites abundantly, on exposure to the air, dipping
55° N. 65° E. Passing southerly on a road to East Lebanon, schists ap-
pear more like those upon Prospect hill. At W. Knight's there is gneiss
dipping 70° S. 50° E. Over the ridge, about on the town line, the schist
has a greenish tint, dipping S. 45° E. Near A. Freeman's, ferruginous
schists dip 80° S. 23° E. Between this hill and the high land west of
the road from Mill Village to Lebanon is a deep and gradually broaden-
ing valley, in which the ledges are concealed ; and those which we should
expect to find there are of the same character with the schists under con-
sideration. Li passing to the south of the village we seem to meet better
defined mica schists, referable to the Coos group, occupying the place of
much of the rock running south from Mill Village ; but the outside vein
of the Bethlehem area from Lebanon village to its extreme southern end,
and thence on the west side through Lebanon and Hanover, is clearly
composed of this feldspathic mica schist. Among other localities I may
cite the school-house north of F. Peabody's, and the north edge of the
Colburn hill in Lebanon (70° N. 80° W.); the valley of Mink brook, and
the west base of Corey hill in Hanover (50° N. 80° W.).

The dark schists just spoken of surround a massive protogene gneiss,
which is the characteristic Bethlehem rock. Its northern end is the top
of the hill back of A. P. Balch's stone house. On Corey hill, near the
summit and by H. H. Marshall's, it has been quarried for building. The
foundations of Culver Hall came from the latter; and those of the Epis-
copal church in Hanover from the former quarry. Other openings are

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 355

on the Sand hill, south-east of the college, in the valley of Mink brook,
near J. Wright's, and near S. Tenney's on the road to Mill Village. The
following are the positions of the strata proceeding east from the Sand
hill along the line of Section VI: Top of hill, 32° N. 55° W.; spotted
gneiss, 33° N. 55° W. and 25° N. 40° W.; thick bedded, with large crys-
tals of flesh-colored feldspar, 58° S. 50° E. north-westerly, the last rock
holding small bits of epidote and tourmaline. These strata are nearly all
monoclinal, the exceptional case being a little east of the centre, and be-
ing evidently a relic of what once represented the position of the whole
eastern half, and what is still retained by the micaceous upper layer. In
other words, this is an example of an inverted anticlinal, not extending
sufficiently far to include the upper division, or else there is a fault at
the east border of the massive heavier member. Essentially a similar
inversion may be seen wherever the area is crossed to the south, as
along Mascomy river and the south part of Lebanon, In the latter local-
ity not only the gneiss and micaceous layers, but also the green, soft
Coos schists adjacent upon both sides, all dip westerly and not at a
very high angle. These facts show the thoroughness of the overturn.

There is a band of gneiss of superior character for quarrying, the coun-
terpart of that on Corey hill, extending southerly from near S. Tenney's
in Hanover, through the high hill south to the west part of the village of
Lebanon. The white ledges east of the school-house, near Freeman's
quarry, seem to belong to this layer. It is quarried extensively at Free-
man's and Walling's openings, on the road from Hanover to Lebanon.
The quarries are arranged in two lines, on the two sides of the anticlinal.
Near the scythe factory are huge blocks of sienite, which are probably in
place near at hand, and may follow the river into the village. Between
J. Ela's and F, Peabody's the gneiss dips north-west. Other facts about
these rocks may be seen upon the small sections crossing them, pre-
sented in Figs. 55-58. The whole series of rocks near the Connecticut
river is repeated in Moose mountain. (See delineation of Section VI.)

3. HURONIAN.

These rocks extend the entire length of the tract under description;
and we may trace the three divisions of them mentioned in the preceding
sketch, viz., Lisbon, Lyman, and Swift Water groups. The first is the

35^ STRATIGRAPHICAL GEOLOGY.

most constant ; the last is recognized only in Haverhill ; the second has
been separated from the first only recently, as I had supposed it did not
extend out of the gold district. Hence I may not be able to separate it
entirely from the first. I will describe the three divisions in the order
of convenience.

Sivift Water Schists. These are properly a part of the preceding
field, extending no farther south than North Haverhill, and being the
extension of those exposed along the Wild Ammonoosuc river. There
are three prongs reaching into the gneissic area. Two have been spoken
of already, in the east part of the Bethlehem gneiss area. Rising from
the modified drift south-east from Woodsville we find a long, gently-
sloping hill, allowing the ledges to appear only on its summit, as about
F, D. Kimball's, the strata dipping 60° N. 60° W. The rock has this
strike in the ledges at Kimball's house, but on the north side of the road
the dip is more westerly. The rock is a micaceous, arenaceous schist.
Garnets are said to be abundant in this neighborhood. Following the
road into Bath, around the north side of the hill, the only ledges seen are
near A. Johnson's, — greenish arenaceous beds, — dipping 40° N. 80° W.
The strike of the rock would carry it to the village just south of How-
ard's island. On the most eastern extension of this group there are
hornblende and argillaceous schists, dipping north-westerly. Near D.
B. Blodgett's, on the town line, slates dip 40° E., with a large mass of
white quartz.

Lyman Group. These strata are not abundant, save in the north part
of Newbury. They occupy most of the section line from Woodsville
across to Boltonville, Vt. (Fig. 45), and they stand upright at Woods-
ville. In Wells River village, ledges are abundant. There seems to be
a ridge of the lower division in the village, perhaps explaining the exist-
ence of the anticlinal. At the first cut in the Montpelier Railroad the
rock is greenish, with many nodular veins of quartz carrying chlorite,
ankerite, iron, and copper pyrites. There is, also, what seemed to me to
be a dyke, about two feet wide, of diabase. Others who have since ex-
amined the locality do not esteem it an injection. Opposite the railroad,
in the anticlinal portion, are layers of dolomite. All these rocks are sug-
gestive of the Lisbon group. If it is present, it is only in small amount,
since the argillitic layers predominate to the west and south.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 357

After passing the green rocks the argillitic schist succeeds in great
profusion, beginning at a steam mill and extending to Boltonville. It is
soft, occurs in thin, slaty layers, and is in this respect different from the
more common variety as seen in Lyman. It weathers white, staining
the rock an inch deep. When fresh there are two shades of green, a
bluish and a drab. Thin layers of a darker variety, and hard, green sand-
stones, are interstratified. The first strikes are almost east and west ;
near the railroad bridge over the river the strike is N. 20 E., dipping N.
70° W. at a very high angle. After reaching the railroad flag station the
ledges are mostly concealed by sand. Half a mile before reaching Bol-
tonville there is a greater proportion of the hard, green schists. Those
by A. Sly's house dip 55° north-west, while at Boltonville dam they dip
85°. The formation probably extends a mile farther up the river, but
everything is concealed. Farther south in Newbury, down nearly the
whole valley of Hall's brook, the Lisbon schists predominate, so that
ground is afforded for believing the lower group comes up west of Bol-
tonville.

The county map represents a conspicuous range of hills from Wells
River village to Mt. Pulaski, below Newbury village. This seems to be
mainly composed of the argillitic strata, which continue into Bradford.
At the railroad cut below Wells river they dip 70° N. 55° W., and are
finely exposed. Further on they dip 75° N. 65° W. They are the same
by C. J. Scott's, or where the railroad nearly touches the river. In the
south part of Newbury village, where crossed by Section VIII, there is
an anticlinal, as if the lower rock came very near to the surface. At the
railroad cut south of Newbury station, close to the Connecticut, the dip
is 85° south-easterly. Where the road turns to cross the bridge, the dip
is 75° S. 80° E. The position is exactly the same thirty rods west, while
on the continuation of the Pulaski schists the dip is 85° N. 80° W.; and
this rock does not extend more than a mile to the west. There are sev-
eral ledges of this rock near South Newbury station. All the Huronian
seen in Bradford belongs to this division. It is prominently exposed by
road cuttings opposite the "Ledge," dipping 70° east. The road from J.
Clark's, back of the "Ledge" down to the fair-ground, runs over Cam-
brian slates, showing that the Lyman slates pass southerly under the_
sand ; but there is a repetition of the latter upon the hill back of Brad-

358 STRATIGRAPHICAL GEOLOGY.

ford village, whose presence can be explained only by the action of eleva-
tion with faults. It runs from the hill at least to the bridge over Wait's
river south-west from the village. At the bridge over this river in the
village the rock is Cambrian. In the south-east part of Bradford we find
a range of the same rock from a school-house near Piermont station to
the east side of the north end of Fairlee pond. It dips 85° easterly at
the school-house; 80° S. 60° E. opposite the turn of the Connecticut
easterly north of Shaw's mountain, and it may be the same by the lake.
This band has not been recognized as yet farther south. To the east
the protogene comes in, composing Shaw's, Sawyer's, and Morey's moun-
tains, crowding out the slates. Further observations will probably show
the existence of this member farther south, since it is only recently that
the Pulaski range has been separated from the lower group.

Lisbo7i Group. Two divisions of this formation may be followed along
the Connecticut river, — first, hard greenstones of various shades of com-
position; second, protogene. The first are the prevailing varieties; the
latter occur occasionally. All that appears in Haverhill and Newbury,
so far as observed, is of this kind. Along the section (Fig. 45) very little
appears, and that in Wells River village and west of Boltonville. It may
exist beneath the sand of Woodsville, since it is known to crop out oppo-
site Howard's island. Along the section (Fig. 47) it is more abundant.
There is a conical hill near the north Newbury bridge, composed of dia-
bases resembling those that yield fossils. The dip is obscure, most prob-
ably easterly. The rocks have been much shattered by the action of
frost. Between the river and Wood's pond is a great development of
these ledges. They are so abundant that the land is mostly uncultivated.
By the Haverhill depot the hard schists dip 75° S. 35° E. Half a mile
north-easterly, on the road to the town-house, the dips are irregular and
westerly, making a synclinal axis. West of Wood's pond green mica-
ceous schists dip north. About half a mile north of the pond the schists
occur for the last time, with north-westerly dips. The ledges are con-
cealed by alluvium, and they are probably Bethlehem gneiss beyond D.
H. Hale's.

At and above the bridge over Oliverian brook, by Haverhill Corner,
argillaceous quartzites appear, very much contorted. The best observa-
tion of the dip is to the cast 70°. Others dip north. A fourth of a mile

Ti..

XIV

-Sections Illustrating the Huronian.-

f/6. 45. Near North Lines or N fwbury and H/^ver h ill

Fi6. ±€. From HalCs Brook , A/ewbury, to Limestone /n Haverhill

Fie. 4-7. From Hedgehog Brook, Newbury, to Fast Haverhill

4 ?? ^^

ilVetsterSlideMt.

Fig. 4r8. From N.E. Bradford to Webster Slide Mountain.

JPierjaont iMTt.

JBSS?-

Fig. 4-5. From 3RADroRO to Piermont Mountain.
VERTICAL Scale, 200 O Feet to an Inch. ^^^
HoRixoNT^Ai. » , 2^ Miles " " "

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 359

above the bridge the dip is south-east. The rock bears some resem-
blance to that in Stark. East of D. Randall's a fine-grained mica schist,
resembling hornblende when water worn, succeeds, dipping 70° W. This
may belong to the Coos group. In Newbury this greenstone range occu-
pies the ox-bow north of the village. At its northern end the ledges are
prominently exposed, large bosses extending to the water's edge, which,
by their superior hardness, have turned the course of the Connecticut.
They dip 75° N. 70° W. The mineral spring near the village comes
from these schists. The valley of Hall's brook in central Newbury is
underlaid by these greenstones. On the water-shed between this and
Wells River, I found large boulders of serpentine, which probably came
from a ledge not far off. The range is broadest about the middle of the
town. It appears on the east side of Ticklenaked pond in Ryegate, dip-
ping 80° N. 80° W., but disappears entirely after reaching the Bradford
line, that last seen having an easterly dip. In Piermont a few ledges
appear in the north-west part of the town, next the Connecticut river.

An important range of protogene commences in a large hill north of
Piermont village, crosses the river at a great bend, rises first into the
isolated Shaw's mountain, and then into Sawyer's and Morey's moun-
tains, terminating with them in Fairlee. East of Piermont hill the pro-
togene and mica schists are separated by a fault about N. 25° E. The
protogene dips east of south, and the mica schists west of south. Near
Gully brook, west of Mrs. E. Bixby's, there is an anticlinal, the dips being
75° N. 30° W. and 70° S. 35° E. On the Vermont side the strata are
usually about vertical. The mountains named have inaccessible preci-
pices on their eastern sides, with debris at their bases, and, as seen from
Orford village, are very conspicuous. One of them was colored as gran-
ite in the geological map of Vermont. The same error occurred there in
the delineation of the similar rock in Northumberland and Lancaster;
and in a statement descriptive of Section X the diabase of Littleton was
called porphyritic granite. The error is an easy one to make on a super-
ficial examination. Without a very thorough study of the relations of
the protogene to the other Huronian members, I have thought it to
occupy a high place in the Lisbon group below the interesting quartz
bosses of Lyman. It does not occur in the valley, as I remember, above
Claremont and south of Vershire.

360 STRATIGRAPHICAL GEOLOGY.

In Orford the Huronian is wanting, unless it is connected with the
soapstones of Sunday mountain and the quarry of Mr. Strong in Orford-
ville. In Lyme a narrow strip occurs above Gilbert's bridge, close to the
river. Large ledges by E. P. Snow's, in the north-west corner of the
town, dip easterly about 70°, and the same at the North Thetford bridge.
Dolomite occurs between these two localities, Fig. 53 showing the rela-
tions of the Huronian and Coos groups in North Lyme. None of the
greenstones crop out in Hanover or Lebanon, but they cross in great
force from Hartland into Plainfield.

The range is continuous from Fairlee southward in Vermont through
Thetford, Norwich, and Hartford. I have not separated the two groups
below Fairlee as yet upon the map. On the first hill north of North
Thetford, hard siliceous schists dip S. 60° E. at their contact with slate.
A mile east of Thetford hill the green schists dip 80° N. 30° W. At a
school-house still farther east, perhaps two thirds of the way to the sta-
tion from the hill, is a quartzite dipping north-westerly 50°. This may
indicate the eastern limit of the Huronian. Following these rocks to
Union Village we find them making an anticlinal, with a strike to the
north-east, where cut down deeply by Pomponoosuc river. The ledges
of this rock extend through Norwich, are abundant, and have been deter-
mined with much pains. The ledges in the north part of the town are
allied to the greenstones holding fossils. A range of argillaceous schist
lies in the Huronian, extending from a little north of the station for two
or three miles. It undoubtedly shows the place of a synclinal line. By
a windmill, half a mile above Hanover bridge, the hornblende comes in
contact with greenstones; and in a railroad cut adjacent there is a large,
unconformable mass of serpentine. Somewhat similar schists make the
cliff for half a mile above. A similar junction appears in railroad cuts
south of the depot, as near the paper-mill. On that line we have, going
west, hornblende schist (the Observatory range) dipping 46° N. 85° W.;
serpentinous mass above it; soft slaty layers, dipping 70° N. 57° W.,
separated from the last by a quarter of a mile of earth covering ; green
schists, with dolomitic layers, vertical, having a strike of N. 5° W.; schists
dipping N. 30° E.; on the ridge, both hard and soft vertical schists; and,
lastly, in the road, half a mile from the depot, dioritic rock dipping 50°
N. 70° W. The Meeting House hill, a mile north of Norwich village, is

. GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 361'

composed of greenstones mostly, with a bed of steatite and cupriferous
schists, once worked for copper. The steatite continues through the
town northerly into Thetford. The ledges north of the village of Nor-
wich are the same diorites. The boundary on the west side appears
about a mile above the village, at a bridge over the stream called Bloody
brook. At Kibling's old mill the schists dip 65° W. The stream exposes
other ledges of the same rock, all of the Lisbon group. In the valley to
the right of the road from the depot to Norwich village are dolomites and
thin-bedded schists, holding many small crystals of magnetite. The east-
ern base of the hill south-west from Norwich village is composed of green-
stones, cropping out at the tannery and on a back road farther south.
Section VI crosses this range in Norwich and Hartford; and the dips
upon it are uniformly high westerly.

A few allusions to Huronian rocks upon Figs. 51, 53, and 55 may be
found in the descriptions of them under the head of Coos Group. The
ledges at Snow's (p. 360) are argillitic.

In Fig. 58 we have the dehneation afforded by the facts descriptive of
Section VI. There is an excellent development of green dioritic schists
by the grist-mill on Bloody brook, near the railroad, dipping 65° westerly.
By S. Godard's, gritty schists dip 50°; and west of J. Newton's in Hart-
ford, at the base of the hill, softer layers appear, dipping 80° N. 80° W.
These facts afford data for perceiving the existence of two or three folds.

The slate range is of considerable width at the north-west angle of
school-district No. 14, Norwich, and appears on both the roads running
west from the Connecticut before coming to the depot. It is an open
question whethet this is an equivalent of the Cambrian, or a part of the
Huronian. Turning on to the Thetford road, at the school-house No.
14, we leave a friable slate, and pass diabases and breccias on the right,
which make up the cliff alongside of the railroad. After passing the slate
range at the angle of the district, we find hard, green sandstones, accom-
panied by dolomite, at school-house No. 5. Similar dioritic schists appear
on the road at W. Johnson's, and on the line between districts 6 and 7.
About half a mile north of Norwich village is a narrow band of cuprifer-
ous schist; and east of the old meeting-house hill, near Deacon Cole-
man's house, is a bed of soapstone, where excellent specimens of green
talc may be obtained.
VOL. II. 46

362 STRATIGRAPHICAL GEOLOGY.

From J. K. Eclgerton's, near the south line of Norwich to the river, \vc
have the following order of Huronian rocks : Greenish sandy schist ; east
of S. Godard's, grit, dipping 50° N. 70° W.; soft green schists ; hard and
slaty layers on top of the ridge, vertical, strike N. 30° E.; green schists,
78° N. 60° W.; dolomitic seams, vertical, strike N. 5° W.; and, lastly,
soft argillitic schists, dip 70° N. 57° W. The last ledge does not reach
the railroad, where the hornblende rock makes its appearance, with the
inverted westerly dip.

An interesting section is that from Craft's hill in Lebanon to a little
north of White River village or Hartford post-office, as delineated in
Fig. 59.

On the south side of White river, by the Hartford post-office, the clay
slates appear in a railroad cut, standing vertical, and full of small faults.
This position seems to be the result of enormous lateral pressure. Great
disturbances appear in the slates, because, being weaker than the hard
Huronian schists adjacent, they yield more easily to the force exerted.
The Huronian schists immediately contiguous to the slates are thin-
bedded, and dip 70° S. E. On the north side of the river, in a tributary
north-south valley, the greenstones properly begin, and extend nearly to
the railroad. At the eastern side of the valley the diorites dip 50° E. 5°
S., and this position is continuous to the top of the hill overlooking the
road to Norwich from White River village. Here the dip of 80° west
commences ; and we find narrow hornblendic layers, diorites, sandy grits,
and diabases, like those holding fossils. Midway to the road from the
hill-top are twenty-five or thirty feet thickness of finely-bedded, white
siliceous rocks. Other layers are of green chlorite schists, with white,
ragged spots of quartz. These may be twelve hundred feet west of the
road. Next come fossiliferous diabase, fine-grained schists, white feld-
spathic sandstone, fossiliferous diabase, and diorites. East of the road
the strata are similar to those described, there being no established order
between the sandstones, diabases, diorites, and siliceous layers. Evidence
is afforded of the existence of two anticlinals and a synclinal in this dis-
tance of nearly a mile. The whole section, therefore (Fig. 59), would in-
dicate five axes, — first, at the east end, an overturn anticlinal ; and lastly,
at the west end, a closely pressed anticlinal. Thus the aspect of the
Huronian is that of an older underlying formation, the slates at the west

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 363

end being supposed to be the same with those in the synclinal between
the road to Norwich and the railroad. The latter arc not certainly seen,
but are believed to continue from the line of exposure fartlicr north in
the east part of Norwich. The thickness of the Iluronian here may be
estimated at about 2500 feet, allowing for five duplications.

On reaching the railroad, a band of hornblende schist crops out, dip-
ping only 45° N. 85° W. This is the range appearing on Observatory
hill in Hanover. The angle of the dip is the same at the lower falls, on
the east bank of the Connecticut river. This is an interesting place to
observe the course of narrow quartz veins, sometimes cutting the strata,
and then running between the planes of deposition. On reaching the
carriage-road, the strata dip 70° W., thus suggesting the presence of an
inverted anticlinal. Passing from the house at the foot of Craft's hill
easterly, loose materials conceal the ledges for 2000 or 3000 feet ; and
then crumbling mica schists, sometimes calcareous, appear in the hillside,
standing about vertical. These belong to the Coos group, and may over-
lie the hornblende schist, which appears higher up and extends nearly to
the summit. The latter dip 75° W., and are certainly four hundred and
fifty feet wide on the surface. Craft's hill has two summits ; and upon
the west side of each the hornblende rock appears, continuous from one
to the other, besides extending down the south slope to cross the Mas-
comy river a mile east of the Connecticut. On the summit ridge, in
several places, are mica schists dipping from 6o°-8o° W., and occasion-
ally holding staurolite. In a few places quartzite occupies beds in these
schists, closely resembling the Coos quartzite of Moose mountain. It
may not be more than a fathom thick upon Craft's hill, but it is thicker
upon Colburn's hill to the north, and is still more abundant in Hanover,
it having been followed through that township into Lyme. Hence it is
believed this small development upon Craft's hill represents the horizon
of the Coos quartzite. The country falls off east of the summit of this
hill ; and the next rocks are the two members of the Bethlehem group
in the Hanover-Lebanon area described on a previous page. The great
value of the eastern part of this section is the development of the whole
Coos group, though in greatly reduced dimensions. Samples of every
part of its representation upon the west side of Moose mountain appear
here. Hence it is plain that the formation is repeated upon Craft's hill;

364 STRATIGRAPHICAL GEOLOGY.

and the materials are afforded for an understanding of the structure of
the rocks in Hanover and Lebanon.

The Huronian rocks range through Hartford soutli of White river, and
then pass through the north-east corner of Hartland, before crossing the
Connecticut into New Hampshire. They are mostly hard, green diorites.
Along White river the strata are nearly vertical, — both diorites and dark
hornblendic varieties. About a mile below the junction there is a rail-
road cut through the hard greenstones. Towards the agricultural society
grounds the yellowish-green hard schists are vertical, with the course N.
13° E. The formation extends to the school-house No. 14 at the cross-
roads. In the south-east corner of Hartford the ledges are mostly con-
cealed by sand. At the falls. North Hartland, the hard green schists
form an island. A mile north they dip 85° N. 70° E.

The Huronian, in crossing the Connecticut below Ouechee falls, has
left several high ledges resembling the piers of a bridge. Seams dipping
85° westerly traverse them, and are believed to represent the stratifica-
tion both of the diorites and the adjacent hornblende schist. The Huro-
nian schists now leave the river, and form the foundations of Willard's
ledge. Numerous embossed ledges of greenstone show themselves over
this hill as far as Beaver brook ; the dips are a little north of west. Newer
rocks and alluvium conceal the Huronian schists to the south of Beaver
brook. There is evidence of the presence of these underlying ledges
about a mile north of the Windsor bridge, in the production of a westerly
dip and an anticlinal in the calciferous schists. Dingleton hill must have
these greenstones within it, since they crop out in a single ledge along
Section V, at its southern end.

The rocks supposed to underlie Dingleton hill appear again in the
ridge south of Walker's brook, in the north-west part of Claremont.
The country between has not been explored. At the school-house No.
19 there are hard, green sandstones, dipping S. 30° W. This reaches
for a mile or more, when the valley of Sugar river intervenes, occupied
by Calciferous mica schist. The continuation of the Huronian is to be
seen in Barber's mountain, in the angle of a large curve in Connecticut
river. The near proximity of the Ascutncy granite suggests a reason
why the bosses in the north-west part of the town should be thrust out
so far east of the continuation of Barber's mountain. The summit of this

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 365

eminence consists of dioritic and dolomitic schists, cut by large veins of
quartz. The dip is quite variable, perhaps the most prominent being 12°
S. 10° W. Others dip due south, and also easterly. On the west side
of the summit there is a south-east dip. To the north of the summit the
rock is more slaty, and inclined southerly. On the south-west side of
the mountain, at J. Woodill's, the rock is somewhat argillitic, dipping 48°
S. 55° E.

Crossing Connecticut river, we find a north-westerly dip of 75° to the
Huronian schists at the south-west angle of the stream, and between the
mouths of two brooks. A similar position seems to pertain to the ledges
on the Claremont side, as seen from Vermont. A little north of Weath-
ersfield Bow post-office the rock is an indurated slate, dipping 80° N. 60°
E. From these observations we conclude, first, that disturbances of con-
tinuity are more common than usual; second, that the structure is anti-
clinal ; third, that the group is the Lisbon rather than the Lyman.

Hornblende Sehist. A band of hornblende schist, forming as it were
the "connecting link" between the Huronian and Coos groups in this
district, may properly be described here. It seems to extend continu-
ously from Orford to Plainfield. Back of Orford street, on the hill, it
dips 65° N. 60° W. Another development of it is near the south-west
corner of the town, on Section VII. A mile and a half east of the north
bridge in Lyme (Fig. 53) this range appears, dipping 50° N. 70° W. It
passes southerly to the west side of Post pond. A similar rock, half a
mile south of Gilbert's bridge, probably dips 60° N. 30° W. This is some-
what associated with the soft, green talcy schists of the Coos group. This
range should properly strike across into the south-east corner of Thetford,
where immense accumulations of soil conceal the ledges. On the south
side of the Pompanoosuc river this rock makes the eminence known as
Blood mountain, on which is a copper mine, the cupreous schists dipping
N. 70° W. There is a similar dip at T. Tilden's house, at the south end
of the same mountain. The range crosses into Hanover at a bend of the
river below Pompanoosuc station, and crops out near the mouth of Slate
brook. There are ledges of hornblende dipping 40° S. W. near the out-
lets of the stream from the town farm and the small brook north of it.
Where the stream follows a ravine, above C. Houston's, this rock dips
about 30° N. W. adjoining the gneiss. Next is the large outcrop of the

366 STRATIGRAPHICAL GEOLOGY.

Observatory hill, from 32°-4i° N. 50° W. The western border of this
band touches Norwich about a quarter of a mile above the depot. Along
Connecticut river the rock appears abundantly below the Ledyard bridge,
as at Negro island, Granny's island, and at both the upper (Olcott's) and
the lower falls. The hill east of these localities shows the same rock rising
above the alluvium. (See plate opposite p. 302, vol. i.) At the upper falls,
east side, the dip is 52° N. 80° W. On the west side of the river the dip
is 44° N. 85° W., and at the railroad nearly 46° N. 85° W. This is at the
extreme western edge of the formation, where it comes in contact with
the Huronian grits. The positions at the lower falls are indicated upon
Fig. 59. Below the lower falls the ledges are frequent as far as the rail-
road bridge by White River Junction. A mile or so south of the junc-
tion the hornblende dips 65° W., nearly in contact with the Huronian.
Opposite this point is a small hummock of the same rock, rising out of
the meadow south of Mascomy river. The formation now increases in
width very much, and lies entirely on the east side of the Connecticut.
West of S. Waterman's a large hill is made of hornblende, dipping 50° S.
65° W. Blood's or Hinckley brook cuts through this hill near the line
of Lebanon and Plainfield, making a deep, narrow gorge seventy-five feet
deep for a distance of half a mile. In this chasm the dip is 50° S. 70°
W. In this neighborhood there are several ledges dipping in the oppo-
site direction, so that two foldings of the strata are inferred. They may
not be of large extent. The noticeable change in the strike is due to the
disappearance of the Bethlehem gneiss to the east, as the hornblende
rock is forced to conform in disposition to the older area. In the north-
west part of Plainfield this ridge is continuous in Governor's and Black
hills. Beyond, our observations are scanty, but we seem to be authorized
to affirm that the hornblende rock ceases to crop out on the surface in
the neighborhood of Mud pond. Ledges of it are marked adjacent to
Connecticut river, in the north-west corner of the town, towards Wil-
lard's ledge, and by Governor's hill. Near W. H. Daniels's the dip is
north-westerly, and the rock is somewhat gneissic.

The range appearing on Craft's hill crosses the Mascomy river with
the railroad, dipping 42° N. 63° W. We arc unable to trace this band
to a direct connection with the main mass farther south. The ledges by
S. Woods's, extending half a mile south to the school-house and dipping

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 36/

80° S. 70° W., also standing on edge, seem to be a repetition of this
band, — perhaps the eastern border of the principal area. (See Fig. 6i.)
In agreement with our theory of the relative ages of the rocks about
Hanover, we have the repetition of the hornblende rock on the east side
of the Bethlehem gneiss, in the central parts of the town, midway be-
tween Hanover centre and Mill Village. The general situation of the
formation along the river is in the line between the Bethlehem group and
the Huronian, with a westerly dip. Inasmuch as a rock of similar min-
eral character is associated with the Coos slates, the first supposition
placed the two together as a part of the newer group. Reflection sug-
gests that it should be regarded as an older member than the Coos, pos-
sibly even underlying the Huronian. Further descriptions will set forth
interesting ranges of hornblende overlying other areas of the Bethlehem
group in Grafton and Cheshire counties, which stand related to the anti-
clinal ridge extending from West Brattleborough to Leyden, Mass., at
Shelburne Falls, Mass., and elsewhere in southern Vermont. They seem
to be more nearly allied to the Huronian than any other system of strata.
It is probable that these schists in Piermont should be referred to the
same age, though for convenience described with the Coos slates farther
along. A limited outlier of the same rock in Cornish will be noticed in
the description of Section V.

Cambrian.

Allusion has been made (p. 311) to the existence of three ranges of
clay slate along the Connecticut valley, — first, the more northern one
from Kirby to Barnet in Vermont; second, the series of basins in the
Ammonoosuc gold field ; and third, the larger area from Fairlee to Hart-
land in Vermont, repeated again below Ascutney from Rockingham to
Massachusetts. Extensive argillaceous and slaty rocks occur on the east
side of the river, and upon previous maps I have colored them the same
with these Vermont ranges. With the exception of the one extending
from Plainfield to Charlestown, upon the east side of the calciferous mica
schist, I think the latter should be placed with the Coos group, since they
often contain staurolite, and especially a multitude of garnets. It is very
uncommon to find these minerals in the former set of ranges, so that for
the present I think it desirable to separate these argillaceous develop-
ments from each other, calling the one Cambrian and the other Coos.

368 STRATIGRAPHICAL GEOLOGY.

Upon our earlier unpublished maps we distinguished a band of con-
torted clay slate, commencing in West Stewartstown and passing north-
erly into Quebec along Hall's stream. The structure of this band on
Sections XIII, XIV, and Fig. 2, Plate VI, is anticlinal. It joins the Cal-
ciferous mica schist, just like the Cambrian in Vermont; and further
facts about it have been given upon pages 40-42. I think it best to give
this band prominence upon the map, and refer it to the Cambrian series.
It often carries minute pebbles, and is full of ferruginous spots, caused,
probably, by the decomposition of ankerite or bitter spar. With these
minerals gold is also found, thus allying the rock to that in Lyman.

The Vermont observations represent the Kirby-Waterford range, with
easterly dips, mostly from yo°-So°. The notch near its northern end is
caused by the existence there of a bunch of granite. There is an abun-
dance of material suitable for building purposes in this area, and the rock
is quarried at two places in Waterford for slates.

Concerning the range properly lying within our present field of descrip-
tion, we may say that all along the eastern border of the Calciferous mica
schist there are many argillaceous bands, so much so that our Vermont
official observations led us to connect together the Waterford and Fairlee
termini. At Barnet, Newbury, and Bradford the argillaceous bands are
prominent. Between the Union church, Newbury (Section VIII), and
Bradford village there may be a fault, which has displaced the slates and
concealed them from sight. At the north-east end of Fairlee pond these
slates are at least two hundred and fifty feet wide, with a high easterly
dip. There has been a quarry in this vicinity, upon the land of Amos
Waterman, and the slate is said by good judges to be excellent. I have
not seen any outcrops on this range, though they undoubtedly exist, till
we come to the turn of the road over the hill to Fairlee lake, near Ely
station. Both here and in the new road following up the brook, the slates
dip about 80° N. 75°-8o° W., and they may be a mile wide. Nearer the
station (Ely) the strata arc vertical. In the north-east part of Thetford
there is a westerly dip, while at the old Howard quarry the dip is 70°-8o°
E. A mile north of the academy the dip is 80° S. 50° E. At the "lead
mine" we have also the south-easterly dip. The slate ledges are abun-
dant between the mine and Potato hill. Between the academy and Union
Village, on the Pompanoosuc river, numerous slate outcrops have been

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 369

observed, many of them showing contortions. Veins of quartz are abun-
dant all through this formation in Thetford. Just above Union Village
the slates are well developed, most of them vertical, and others nearest
the Huronian dipping 80"^ easterly in consequence of an overturn. The
Union Village Huronian anticlinal has been the older rock, whose north-
westerly pushing has produced this overturn. I have followed the range
from the Pompanoosuc to Norwich village, and find it standing vertical
for the most part. At G. W. Simmonds's it dips 85° S. 65° E., and it is
about the same at E. Johnson's. A valley has been excavated by the
east branch of Bloody brook between Meeting-House hill on the east,
and an equally lofty eminence to the west. The east edge of the slates
is well shown at the crossing of Bloody brook at S. Wright's. It also
crops out in the valley of this brook in school-districts Nos. 17 and 11,
not extending above school-house No. ii. The hill west of Norwich vil-
lage is entirely composed of this same clay slate. The rock shows itself,
also, in the valley of the stream descending from school-house No. 2. To
reach these last-named localities, the slate bends considerably southerly.
In the edge of Hartford, along the valley of a stream, the slate dips 80°
N. 80° W. Between this and White River valley no observations have
been made. In the last-named region, near Hartford post-ofBce, a rail-
road cut exhibits vertical and disturbed slates, and there is a greater
breadth of measures. Not far to the west of school-house No. 14, the
slates dip 70° N. 70° W., and the country rises. At a bend in the road
farther west, the slates dip 70° S. 70° E., thus making a synclinal axis.
The slates continue to the foot of a higher range of hills forming the
dividing ridge between the Quechee and Connecticut rivers. Along this
line, parallel wath White river, the formation is twice as wide as it is far-
ther south. It diminishes towards North Hartland. At the south end
of this village the slate dips 75° E. If the range follows the adjacent
Huronian, it should cross the Connecticut here ; but there are no clay
slates of consequence opposite in Plainfield. Hence, for the present, we
must believe the formation terminates at North Hartland, and it is so
represented upon the map.

Our studies of this range have been fragmentary; but we seem to have
evidence of an anticlinal in Fairlee, an overturn synclinal at Union Vil-
lage, a synclinal, with enough measures to supply other axes, in Hartford,
VOL. II. 47

3/0 STRATIGRAPHICAL GEOLOGY,

etc. I suppose the formation marks a horizon between the Huronian and
Calciferous mica schist.

The quartz veins of Thetford are auriferous, and resemble those of Ly-
man, The galena is more abundant in the former locality ; and the other
characteristic minerals, as ankerite, blende, and mispickel, are present.
Quartz veins occur also in Norwich and Hartford; and in the latter town
there is said to be a gold-mining location.

There is another range of clay slate connecting our two areas of de-
scription, to the east of the Connecticut and the Calciferous, from south-
ern Plainfield to North Charlestown. It bears the same relation to the
Cornish and Plainfield area of Calciferous mica schist that the Thetford
range just described does to the great Calciferous range to the west. In
Plainfield the ledges lie a short distance east of the school-house No. i6.
Many of the exposures in the east part of Cornish resemble this series ;
and on the west slope of Croydon mountain, opposite Parsonage hill,
there is a quarry of slate, the flags dipping 60° S. 80° E. Their exten-
sion southward is noted as argillaceous in the deep valley of a small
stream between N, Lear's and Mrs. Huggins's, and their position is sim-
ilar to that just noted. In Claremont the slates are much better devel-
oped. There is a small quarry on Redwater brook, in the north edge of
the town ; and Bald mountain is mainly composed of this rock, with in-
tercalated sandstones and quartzites. Between Bald and Green moun-
tains, on the "cat hole road," there are clay slates dipping 40° E. They
occur at intervals on the road following around the west and south flanks
of Green mountain, dipping S, ^y" E, very near the junction of the slate
with quartzite. In the valley of Sugar river, towards the village of Clare-
mont, the ledges show evident marks of distortion, with average, dips of
70° S, 85°-87° E. They are also permeated by many fissures, produced
in comparatively modern times, since they are not filled by veins. At
Mrs. O. Walker's there is a dip of 6y° N. 70° W,, which may be of limited
extent. Farther east there is another small synclinal, the basin being not
more than fifty feet wide. Of this the westerly dip on the east side is
very steep, while the easterly dip on the west side is not over thirty de-
grees. At the end of this side road, by S. Nott's, the dips are mostly to
the east, with the strike N. 30° E. Nearly opposite, on the main river
road, we find a strike N. 7° W,, and easterly dip. Near H, Hubbard's

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 37 1

the dip is 80° S. 62° E. For half a mile north of Hubbard's the slate
becomes micaceous, dipping 60° N. yj" W. A section of the rocks along
Sugar river is given farther on. The slate does not underlie the principal
village, though it touches its south-east extension, approaching the rail-
road station. The west line runs over the westerly slope of Bible hill, the
hill itself and the Flat Top near the village being composed of slate.
At a reservoir on the northern slope of Flat Top hill the strike is N. 27°
E., the strata being vertical or leaning slightly to the east. On the east
side the westerly dip is strongly marked. On top, the irregularities in
dip prevail, on the east side dipping 75 '^ N. W., and on the very apex
34°-50° S. E. On the summit of Bible hill, the highest part of the rock
mass of which Flat Top is the northern spur, the dip is about 85° S. E.,
with north-westerly variations. In descending south-westerly, we observe
a large vein of white quartz. Near R. Cassady's there is a bed, ten feet
thick, of quartzite, full of minute undulations. Near N. Stone's house the
strike is north-east, and the dip is vertical. This house marks the west
edge of the formation. The mica schists adjacent dip towards the slate.

I had occasion to examine Bible hill more carefully than usual, and
was impressed strongly by two classes of facts : First, the great diversity
in the position of the strata. As indicated above, north-westerly and
south-easterly dips are mixed together confusedly. It may be explained
by the second class, viz., the existence of numerous fissures of modern
origin, say post-glacial. I have never observed such fissures elsewhere
so abundant as here, either because attention was not specially directed
to them, or they do not exist. The fissures have probably been made
since the ice period, because the hill-top is covered by striae. Had the
cracks been as abundant when the glacier pummeled the hill, the ledge
could hardly have resisted its blows. It would have been carried away,
and the Sugar River valley been much widened. These fractures have
probably been caused by the lateral pressure, which shows itself often-
times in quarrying. When the strain is taken off by the removal of large
blocks, the tension will relieve itself by a spreading or moving of the
rock.

To the south the slates diminish. They occur at North Charlestown,
on Calavant hill, with nodular masses of quartz thought to be auriferous.
A hornblendic rock — possibly gneiss — from the east point of this hill,

372 STRATIGRAPHICAL GEOLOGY,

together with the slate itself, is a little suggestive of Huronian. Towards
the village of North Charlestown I have an observation of a dip of 80°
S. E. In Springfield, Vt., near school-house No. i, the slates crop out
strongly, dipping 50° S. E., and holding auriferous quartz veins. There
is also an observation of slaty rocks at N. Spaulding's, in the north part
of district No. 6. These outcrops are the last seen of this range, and it
is believed to be cut off by the rising up of the quartzite and Huronian
in Springfield, about Skitchawang mountain. The line of slate outcrop
is therefore situated between two Huronian masses, — Barber's mountain
to the north in Claremont, and near Skitchawang to the south in Spring-
field. It is possible that the Huronian hills existed before the mud of
the Cambrian period was deposited beneath the quiet waters. Beginning
in Plainfield, this band of slate has Coos schists upon the east ; next, are
quartzites in Claremont ; Coos schists in North Charlestown ; and, finally,
the Huronian and Coos quartzite in Springfield. On the west side the
border is uniformly the Calciferous mica schist. It will be quite desir-
able, in order that these formations be thoroughly understood, to investi-
gate further the south-west end of this slate range.

COOS QUARTZITE.

There are fifteen or twenty areas of quartzite near the eastern border
of the Connecticut Valley district, between Lisbon and Claremont, which
are grouped with the Co5s slates on account of their proximity and inti-
mate association. Some of them repose upon gneiss, entirely isolated
from all connection with the staurolitic schists. They also extend to Ber-
nardston, Mass., and may have some connection with the quartzites con-
nected with the Helderberg limestone there. For these reasons, they
are described by themselves, and are distinguished from all other forma-
tions upon the map.

Mr. Huntington has examined most of these areas, and will describe
them in the next section. I will only speak of a few things which he
has not seen.

Starting at Landaff, there are one or two isolated patches of sandstone;
and then commences the range which is so curiously developed among
the mountains in the west part of Benton and eastern Haverhill. After
passing the gap of the Oliverian stream in East Haverhill, there succeeds

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 373

the beautiful quartzite culminating in Piermont mountain, and terminat-
ing in the north part of Orford. Then there follow, possibly connected
directly with the preceding, the mass of Mt. Cuba, and several isolated
patches in Wentworth and Dorchester. Next, there is a Lyme range;
then comes the Moose Mountain mass in Hanover, terminating obscurely
in the east part of Lebanon. Several insignificant outliers occur in the
gap ensuing before the quartzite gathers itself together to form the Croy-
don Mountain mass. Li Claremont and Newport there is another devel-
opment, seemingly curving round an area of Bethlehem gneiss. Towards
the river there is an interesting bed of quartzite, quite narrow, but dis-
cernible through Lyme, Hanover, and Lebanon. A few others will be
mentioned presently.

]\rt. Cuba. A hasty climb of Mt. Cuba in Orford will show the rela-
tions of this quartzite to the accompanying schist. Starting from "Hall-
town" on the west side, and passing thence up the north edge of the
mountain, we leave Bethlehem gneiss standing on edge, and come to ex-
ceedingly twisted thin layers of rusty staurolite mica schist, with strike
N. 3° W. Another ledge standing vertically has the strike N, 5° E.
Still farther east, about one third of the distance up the mountain, the
same rock dips 85° S. 85° E. From a third to half the distance up, we
find quartzite dipping 70°, 75°, and 80° S. 20° E. After reaching the
first eminence, or outlying spur of the mountain, we again discover the
hard mica schist, — another mass, — but it is not extensive. The apex of
the mountain is composed of the quartzite, hyaline, and dipping N. 65°
W. I had no time to explore the woods to the south. In order to prop-
erly understand the relation of the mica schist and quartzite, we need a
model of the mountain carefully constructed from a perambulation of the
entire surface. Judging from all the data at command, it would appear
that this quartzite is of an oval shape, unconformably reposing upon
gneiss, with some intermixture of mica schist. Fig. 5 i shows its situa-
tion, in relation to the other rocks, as well as we can judge. The shape
of Cuba and Smart's mountains is such that, from a distance, one would
think the rock was continuous from one to the other ; but I believe ob-
servation does not verify this anticipation. It is not impossible, however,
that the Cuba Mountain mass should join the continuation of the Pier-
mont range. Between the two the ledges are concealed by soil; and

374 STRATIGRAPIIICAL GEOLOGY,

their directions seem to correspond, save that the first quartzite seen in
our ascent dips to the south, overlying mica schist and gneiss. If, how-
ever, there were an upthrow of the mountain, the facts would be con-
sistent with a former union of the two.

The Western Range. Quite recently the facts establishing the exist-
ence of a narrow but persistent range of quartzite in the west part of
Orford, Lyme, Hanover, and Lebanon have been observed. It seems to
follow the western border of the Hanover-Lebanon area of Bethlehem
gneiss. Commencing in the south part of Lebanon, we find large blocks,
and, I believe, ledges of a conglomeratic quartz, east of A. Hall's and sons.
They occupy a hill-top, extending nearly a mile northerly past the two
Stearns houses. This layer cannot be large. Upon Craft's hill a stra-
tum of it, perhaps three feet thick, may be seen in two places. There is
another outcrop of quartzite on the south side of the top of Colburn hill,
and there are some appearances of it on the long north slope towards
Hanover plain. In the valley of Mink brook, and through much of Han-
over, this rock is concealed. Back of C. Houston's, there is an outcrop
conspicuous for a long distance. We begin to find many ledges of this
rock on a large brook opposite Pompanoosuc. Near F. Merrill's it is a
sandstone, dipping 40° N. 48° W. It may be followed for a mile along
the hill road to Lyme with certainty, cropping out in several places.
In Lyme, in the bend of Fairfield brook, it appears again, also at Lyme
church ; and the hill west shows a white rock like it, but it has not been
visited. It is equally plain to the east of the road to Post pond. It is
unusually thick at the fork of the road north-east of Post pond, dipping
north-westerly. High up the west side of Acorn hill, as you take the
north-east road from Post pond, the same rock appears. At J. Hall's
the quartzite dips 75° N. 50° W. There is a mass of quartzite, on the
south-west side of Indian pond in the north part of Orford, eight miles
distant, which may belong to the same band ; for that traced northerly
from Lebanon skirts the west line of the Bethlehem gneiss, and this in
Orford occupies the same stratigraphical horizon. Future search may de-
tect occasional ledges of quartzite through Orford, connecting the two
remote points. It is worthy of note, however, that the quartzite immedi-
ately adjacent to the gneiss is much more limited than that connecting the
two Bethlehem areas together, from Merrill's in Hanover to Hall's in the

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 375

north part of Lyme. The Moose Mountain and other ranges border the
Bethlehem gneiss as well as the longer range near the Connecticut river.
Both areas lie upon the west flanks of the gneiss, and none occur upon
the eastern. Both occur in staurolite mica schists, while the western
comes very close to hornblende rock all the way, though probably not
connected with it. These ranges are undoubtedly of the same age, and
originally constituted beaches upon the shores of Bethlehem islands.

Moose Moiintain Range. The gap between Bear hill, Lyme, which is
the southern end of a quartzite area, and Moose mountain, Hanover, is
one thousand feet above the sea. The valley is covered by drift, and
might conceal this rock, save that the south end of Bear hill is so com-
pletely occupied by other rocks that there is no place for it. Moose
mountain rises very rapidly 1300 feet above the valley; and it is easy to
see, from the hills north, the gradual thickening of the white quartzite
from below upwards. This range, as conspicuous as Cuba, Piermont, and
other similar mountains to the north, owes its existence, like the others
named, to the presence of quartzite. On the road over this mountain
the quartzite dips 50° N. W. Nearly three miles farther south the dip
is 72° W., and it is somewhat interstratified with mica schist. Less than
a mile farther, the observed dip is 80° W., and the rock occupies the very
crest of the mountain. The course, which has been south, now changes
to a few degrees east of south. Almost at the south-east corner of the
town, it doubles back westerly so as to run S. 33° W., and abruptly dis-
appears beneath the slates as if it were broken off, while its thickness is
not great. A considerable search in the neighborhood, in East Lebanon
and the north-west part of Enfield, fails to find any trace of the continua-
tion of this particular type of quartzite. The boundary between the slates
and gneiss has been carefully examined ; and nothing is met with north
of Lily ponds, where it is largely developed, and probably dips westerly.
It lies in the proper stratigraphical position, between the slates and the
gneiss ; and it is likely that the material is wanting in the Mascomy val-
ley, just as it was along Fairfield brook in Lyme, at the north end of the
range. I have never explored Mt. Tug — 1700 feet — (980 above the lake),
which is in a direct line between the last exposure seen upon Moose
mountain and another locality about to be mentioned. The rocks have
a south-westerly strike, as if the two quartzites might be continuous.

376 STRATIGRAPHICAL GEOLOGY.

Much of the mountain is bare, and, as seen from the road, looks alto-
gether like slate. There are large boulders of an interesting conglom-,
erate of quartz pebbles in a brook crossed by the road east of Mt. Tug,
which must have come from this range.

East Lebanon Areas. I regret never to have worked out the relations
of several small quartzite areas in the east part of Lebanon, etc., the first
of which is in the line of the Moose Mountain rock, after its westerly-
bend. It is probable it is a repetition of the same band, by folding, per-
haps, under the synclinal which is observable between the sides of the
valley by Walker's slate quarry in Hanover. A friable sandstone, from
fifteen to twenty feet thick, known in the neighborhood as the "Sand-
hill," is a landmark on the sloping ridge west of the slate quarry. On
the south side of the valley, back of J. W. Cleveland's, is a hard quartz,
often showing constituent pebbles, twenty-five feet wide, and carrying
mispickel. At one place it has been broken, and one end shifted about
twenty-five feet. The dip is 75° N. 75° E. On climbing the hill, it is
again seen before coming to I. Eastman's. The argillaceous schists about
it are much twisted. A quarter of a mile south of Eastman's is a short
piece of quartzite, which looks as if it had broken out of the long reach
of this rock, continuous for three or four miles S. 8° E. from the sand-hill.
This fragment dips 60° N. 20° E. West of A. P. Hoyt's, the range is
continuous for more than a mile to the Enfield line. Two other outcrops,
apparently belonging to the same range, are just south of Stony brook
and near a church in the south-west corner of Enfield. This would seem
to be continued in the area west of school-house No. 14 in Plainfield, on
the course of Ring brook, if extended. An outcrop west of Leavitt pond,
in the edge of Grantham, appears to be the continuation of the Lily Pond
(Enfield) exposures. That at the Grantham Lily pond is obviously con-
nected with the Croydon Mountain mass, and perhaps another small one
south-west from Sugar hill. There remain two others not yet mentioned.
The first is a quartz conglomerate, about a mile above the mouth of Stony
brook in Lebanon; the other is south of East Plainfield, — and both are
equahy distant from the other ranges. It may be that the suggested syn-
clinal at Walker's quarry is continued southerly, so that the Enfield and
Stony IBrook ranges are the same, uniting again in Grantham or Croy-
don mountains. In that case, the two more western outcrops might be

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 377

the indication of an anticlinal on the west side. With this latter range
would naturally be associated the Bald Mountain outcrops in the north-
east part of Claremont. There are three bands there, at least one of
them being- a beautifully spotted rock, with white, flattened pebbles in a
dark, slightly argillaceous paste. One of the dips is N. 80° E. An ob-
scure quartzite occurs a short distance above J. Clark's saw-mill, which
may connect with one of the Bald Mountain exposures. After another
look at the map, it seems possible that these eastern ranges are all con-
verging towards the Craft's Hill range. The nucleus of Bethlehem gneiss
undoubtedly causes this convergence, and further exploration may pos-
sibly illustrate this feature more strikingly. The most western of the
eastern ranges, near the mouth of Stony brook and Bald hill, is the one
most like the Craft's Hill band, and the one that would most naturally
join it in case the convergence became conjunction.

Croydon Range. One gets the impression that the whole of Croydon
mountain, in Grantham and Croydon, must be composed of quartzite.
Plans that were made for the exploration of these mountains have failed
to be carried out; and therefore the coloring of this area must not be
regarded as necessarily correct. Beginning quite high ujd, near Cranberry
pond, with westerly dips, the rock continues southerly into the Grantham
mountain, the land rising all the way. Traversing the road at the east
foot of the Grantham mountain, one gets glimpses of supposed quartzite
ledges on the summit. In the notch, where the Croydon road passes
over to Cornish Flat, the quartzite is abundant. At the east base it
dips 75° N. W., or at a much higher angle than the underlying gneiss.
After passing a band of white, vitreous quartz in the ascent, there is a
mica schist dipping 50'' S. 80° E.; and this is probably the range which
extends northerly to the Croydon trigonometrical station occupied by
the Coast Survey party in 1874. At the summit there is more quartzite,
dipping 50° southerly. The south end of Croydon mountain is certainly
quartzite, dipping 70° N. 75° W. and 60° N. 85° W., and to some extent
is interstratified with varieties of mica schist in the district a fourth of a
mile west of the Croydon mine. I have no evidence to show that the
quartzite extends out of Croydon into Newport.

Claremont Area. There may be quartzite upon the north-west side of
Green mountain. There is but little adjoining the slate by C. Dean's, on

VOL. II. 48

3/8 STRATIGRAPHICAL GEOLOGY.

the south side, but it widens southerly. It is quarried near R. Page's,
and is near hornblendic, chloritic, and garnetiferous schists. At A. C.
Dodge's it is a conglomerate, composed of flattened pebbles, dipping 75°
S. 85° E. There is said to be quartzite on the south side of Sugar river,
on the east side of Bible hill. If so, it is the natural continuation of this
range. I have seen there only a very large vein of white quartz, cutting
the mica schists west of D. W. Barney's, near the south line of Claremont.
It appears that the gneissic rocks east of this range belong to the Beth-
lehem group ; and that around its north end, in Claremont and Newport,
the same band occurs, perhaps all the way, though colored upon the map
only where it has been seen.

5. Coos Schists and Slates.

Most of the area between the Huronian and the Quartzites is occupied
by mica schists, clay slates, and a few hornblende schists, believed to be-
long to a group of strata not well understood, and therefore described
under a local geographical name of no original geological significance.
Their easy passage into the group described in the Vermont geological
report as the Calciferous mica schist, makes it difficult to decide between
them in many cases. I am sometimes disposed to maintain that the two
were synchronous, the calcareous layers forming in deeper waters than
the sandy and clayey sediments of the Coos series.

There is a natural separation between the Coos schists of the Ammo-
noosuc and Connecticut Valley areas. The Haverhill gneisses form an
impassable barrier between them, not likely to have been overcome un-
less it were far back in Paleozoic time. The rocks are largely argillo-
micaceous schists in the south part of Haverhill. Perhaps the most
northerly outcrop of it is on the south slope of Knight's hill, dipping 80°
N. 20° W. They crop out on the ridge east of Wood's pond, with an
inclination of 75° N. 40° W, Fig, 48 shows the order and position of
the formations near the southern line of Haverhill. Leaving the gneiss
inclined only twenty degrees westerly, the quartzite first appears, dipping
45° N. 30° W. Then we have wrinkled staurolite slate, with a smaller
dip. This is followed by hornblende schist, dipping 80° N. 80° W., occu-
pying about half the space between the quartzite and the turn of the road
down Eastman's brook; afterwards, in the whetstone slate at a quarry.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 379

with a variable dip of 30°-8o'' W, Tliis is followed by hornblende again,
the slate having been quite limited in amount. Near the forks of a road
leading to East Haverhill there is a broader band of whetstone, three
hundred feet wide, and a larger (the principal) quarry. This extends
north-easterly to join other gneisses of the same material in East Haver-
hill, Hornblende succeeds again. Without specifying the changes in
order, it is sufificient to say that there are five bands of hornblende schist
and five of whetstone slate between the quartzite of Iron Ore mountain
and the stream flowing northerly into Oliverian brook on the north-east
part of the town line between Piermont and Haverhill. The map shows
only one of these hornblendic outcrops. The last half mile of Piermont
shows a good soil, with the ledges mostly concealed. This suggests the
presence of the limestone of the Calciferous. The hornblende, close to a
school-house near the town line, dips 65° N. 70° W.

I am inclined to carry out the suggestion of a previous page, to the
effect that much of this hornblende should be regarded as Huronian. In
agreement with this notion, it would form hummocks underlying the
mica schists, probably unconformably. Such is the present relation of
the first staurolite and hornblende schists mentioned upon this section.
Lateral force exerted in subsequent periods seems to have exaggerated
the discordance. This theory will explain the occurrence of the whet-
stone rock, in limited outlying patches, sometimes exhausted by quarry-
ing. Were it interstratified with the hornblende, it should descend into
the earth at the same angle to indefinite depths. This theory, then, re-
gards the eastern part of the hornblende of Piermont the same with that
in Hanover, Eyme, and Orford, bordering the west line of the Bethlehem
group. A similar view will make plain the proper relations of the horn-
blende rock in Fig. 59; but the more western of these hornblende ranges
must remain with the Coos group, as they are evidently interstratified
with each other.

On ascending the west side of the valley, on the town line just named,
the ledges bear more resemblance to the calciferous layers found in Ver-
mont. They dip 70° S. 75° W. There is a little hornblende with it at
first, then it is soft, and, by J. Wallace's, hard, from the abundance of
silica. On Catamount hill, just in the edge of Piermont, is an interest-
ing mass of eruptive granite, unlike any other granite seen in the state.

380 STRATIGRAPHICAL GEOLOGY.

The three constituents are about equally developed. The general effect
of the stone is like that of the Concord variety, only the mica is blacker
and more abundant. It is extensively quarried. Its period of eruption
must be set down as subsequent to the deposition of the Coos slates,
since the latter have been disturbed by its protrusion ; yet the direc-
tion of the dip is unchanged, as at J. Blaisdell's in Piermont, dipping 70°
N. 50° W. The Haverhill Corner (court-house) village lies on a hill of
drift, and hence the junction of the Coos and Huronian systems is not
exposed ; but, by following up the valley of the Oliverian stream, one can
see much of the structure. At the bridge in the village the rock is the
argillitic Huronian quartzite, dipping east and S. 65° E., and continuing
for a quarter of a mile up the brook. The Coos schists commence near
D. Randall's, dipping 70° west. It slightly resembles hornblende when
water-worn, decomposing readily. Higher up the Oliverian, the strike
changes to east of north. At P. P. Bowen's the dip is west. There are
several good exposures of these schists on the railroad between Haver-
hill and East Haverhill stations.

The order of rocks down Eastman's brook in Piermont has been care-
fully ascertained. As before (Fig. 48), we start with quartzite, staurolite
schist, hornblende, and the first whetstone slate dipping 70° W. at the
junction of the roads from Piermont and Haverhill villages. Then we
have hornblende, whetstone, with dip 65° W., and hornblende with strike
N. 30° E., vertical. On the hill south the next layer is a small band of
quartzite, with whetstone slate, dipping 60° N. 80° W. Then comes an-
other small quartzite layer. Between A. C. Walker's and H. Chandler's
there is a synclinal of argillaceous schist or slate, the dips being 70° N.
60° W. and 80° S. 55° E. This is related to the slates occurring north-
westerly at A. W. Putnam's, just in the edge of Haverhill. The rest of
the rock to the village of Piermont is mostly mica schist, with and with-
out staurolite. Our observations are 54° N. 50° W., 50° N. 60° W; horn-
blende band, ss"' N. 20° W., 35° N. 60° W., 45° N. 55° W., and 45° N. 60°
W. at the village. Just to the south of the river is a noticeable conical
hill, called "Peaked," whose composition is the prevailing rock of the
country. It is not easy to comprehend why this conical mass should
have been spared, while the adjoining strata were eroded. Similar cases,
however, occur in the towns south. First, we have Sunday mountain in

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 38 1

Orford ; and, second, Acorn hill in Lyme, — the first more difficult to un-
derstand than the Piermont Peaked hill. West of Piermont village there
is a hard argillite, dipping 20° N., adjacent to Huronian protogene. On
the road to Haverhill, the Coos rocks come in contact with the Huronian,
likewise, in connection with a fault. The protogene dips 60° S. 20° E.;
while close by the mica schists dip 70° S., the common position being to
N. 50° W. The line of the fault, as mentioned upon page 359, is about
N. 25° E.

There is a hilly country, not at all inhabited, between Eastman's brook
and Catamount hill, concerning whose geology nothing is known. While
the probabilities are in favor of its being, as represented upon the map,
the continuation of the mica schists, it may be granitic, or gneissic, or
hornblendic. Such a composition as the granitic would better agree with
the lack of inhabitants, the presumption being that the poverty of the
soil occasions the absence of farms. The west part of Fig. 49 is included
in the description of the rocks along Eastman's brook. To the east of
Peaked hill the line of this section leaves the river and passes directly
to Piermont mountain. On that there are mica schists, dipping 50° and
55° N. 54° W., also 80° N. 40° W. These are supposed to continue uni-
formly to the quartzite. Near the Christian church on Bean brook, a
little south of this section, we have a dip of 85° S. 32° E., which would
seem to indicate the place of a fold in the strata.

The hills in the south part of Piermont remind one of the character-
istic domes of the limestone region. They are very high, rounded, with
deep valleys between them, while good farms occur universally. Start-
ing south-easterly from Piermont village for Indian pond, we find the fol-
lowing facts: At the village the dip is N. 50° W.; on top of the first hill,
the continuation of the Peaked Hill range, the mica schists are slightly
stauroliferous, dipping N. 60° W., with a small overturn anticlinal, the
steepest pitch being upon the south-east side. Whether this small fold
is local or not, I cannot say. The north-west dips occupy the south-east
side of the range. Beyond Bean brook there is a higher hill, with mica
schist dipping 8o°-85° N. 70° W. Just in the edge of Orford the schists
are pyritiferous.

These rocks in the north part of Orford are represented in Fig. 50, a
section from Pine hill to the Soapstone mountain. On Pine hill are the

382 STRATIGRAPHICAL GEOLOGY.

highly inclined strata of Bethlehem gneiss (p. 351). Near the four cor-
ners, south-west from Indian pond, is a band of quartzite dipping 65° N,
60° W. At the school-house by the corners are vertical slates, becom-
ing notably minutely contorted beyond. A little north of the road, by
J. Stickney's, the dip is 6"]° N. 38° W. The dip is obscure west of T.
Ames's, thought possibly to be easterly. At E. Lovejoy's are large loose
slabs of siliceous limestone. On the long dome hill beyond, the north-
westerly dip is the common one, one observation being 75° N. 34° W.
Echo hill is a conical, isolated rock, precipitous on the east side. South-
west from it, near T. Ford's, the rock is sandy, dipping 20°-30° N. 40°
W. The strike is perceptible here for several rods in extent. On top of
Soapstone mountain, which is properly on the section line, the dip is 30°
N. 25° W. The mica schist here is full of small contortions, whose axes
run north and south, like those on Sunday mountain, showing that the
shoving force came either from the east or the west. This moderate dip
continues to the soapstone quarry on the southern slope, where it varies
from 30°-40° N. 45° W. Some of the layers have a little feldspar; but
this soapstone is essentially in the Coos formation. There is a sugges-
tion, not yet verified by analysis, that the mineral is agalmatolite. It con-
tains the rare brown tourmaline. The bed is forty or fifty feet thick, and
is not now worked.

Next we have a section from Cuba across Sunday mountain to Orford
street (Fig. 51). The rocks of Mt. Cuba have been somewhat noticed
already. A bunch of mica schist seems to be caught in the quartzite,
and there is another mass on the west side below the quartzite. Both
these formations rest on the edges of Bethlehem gneiss. Between Cuba
and Sunday mountains we find an anticlinal of gneiss in the low country.
The first of the mica schists dip 75° N. 40° W. at the union of the four
roads. Two miles north, on the strike of the east part of Sunday moun-
tain, there is a slight leaning to the west ; and the course of the schists
on the north side points towards the curious conical mass. On top of
Sunday mountain garnetiferous schists dip N. 30° W. It is a little feld-
spathic on the west slope. At the west base of the highest part of the
mountain, in a small valley, soapstone crops out, inclined 60° N. 58° W.
The same rock occurs on the south-east slope, and there is said to be an-
other to the north, thus making four beds of this mineral in Orford in the

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 383

mica schists. Probably these four are continuations of the same bed, re-
peated by undulations of the strata. As the dip is essentially monoclinal,
the repeated occurrence of the same rock indicates overturns. On the
south side are nests and crystals of chlorite. The west side of Sunday
mountain furnishes admirable examples of contorted strata on a small
scale ; and I have obtained a large block of the stone showing them, for
the museum. If it were figured, the curves would be like those already
given, on Plate X, of the boulder from Bemis brook. The dip by the town
farm, on the north-west slope, is N. 40° W. On the line of section, just
west of the North Branch valley, the dip is not more than thirty degrees
in the same direction. At the grist-mill, at the north end of the "street,"
we find argillo-mica schists, with staurolite in distinct crystals, in hori-
zontal disposition, and also inclined as high as 25° N. 50° W. At one
exposure there is a small, shallow synclinal. Cleavage planes, cutting
the strata and highly inclined, are also present, which is uncommon in
New Hampshire. A related example may be seen east of the cheese
factory, perhaps two miles east of the centre of the village. The first
ledge is of argillaceous schist, at the fork in the roads, apparently dipping
65° N. 45° W. A few rods east there seem to be stratified layers, dip-
ping 20° S. 15° E., while cleavage planes occur corresponding with the
supposed strata of the first ledge described. There are several other out-
crops similar to the first ; but no others, like the second case mentioned,
have been seen close at hand.

The north-west dip is resumed at Orfordville and westward, but there
is a development, a hundred yards wide, of what is probably Huronian.
In the east part of the village is a bed of soapstone, in argillitic schists,
with mineral aspects different from that in the other localities described.
It is green, like chlorite. The excavation, when examined, Sept. 20, i "^^2,
proved to be about sixty feet long and twenty feet deep in one part. The
stone occurred in three places, and seemed to occupy three undulations
of the strata, with two small faults. The strike is N. 17° E., and the dip
is N. 73° W., all the layers being inverted. The course is towards Sun-
day mountain. Should this ancient rock occur beneath that eminence,
we can understand its origin, since the elevation of the floor must of ne-
cessity raise up the underlying schists above those of the neighborhood.
A narrow Huronian axis, just including the soapstone band and inclosed

384 STRATIGRAPHICAL GEOLOGY.

within newer Coos rocks, with the same monodinal dip, would not be the
most unreasonable method of accounting for the presence of this rock,
which has heretofore been supposed to be confined to the older forma-
tions in New England.

A visit to Strong's quarry in 1875 showed a greater thickness of soap-
stone than appeared at first; and many of the adjacent rocks seemed to
be charged with talc, so as to be genuine talcose schists. Passing to the
south-west, a mongrel rock occurs, covering the soapstone quarry univer-
sally, with the dip of N. 45° W. along the line of the quarry. This is fol-
lowed by a hornblende, dipping 65° N. 55° W.

In Fig. 52 there is a section from Bass hill to the Connecticut, a mile
north of the south town line. The east side of the hill consists of the
granitic Bethlehem gneiss, which dips N. 55° W., probably 80°. At the
summit, or a little west of it, may be seen the meeting of the gneiss with
argillo-arenaceous schists, dipping 80° S. 50° E. This is an overturn, and
is not seen away from the hill-top. At the west base the dip is 75° W.;
and farther north mica schists, with alternating bands of quartzite, dip
70° N. 47° W. At the first bridge east of the Strong quarry, the dip is
58° N. 46° W. Then occur the dips at the quarry and farther south,
mentioned above. Near N. & T. M. Rugg's, the dip is 70° N. 60° W.;
west of the same, 6S° N. 50° W.; half a mile west, 50° N. 60° W.; at J.
C. Sanborn's, 65° N. 55° W.; near D. E. Tillotson's, 50° N. 80° W. These
are all argillaceous. A mile west of Tillotson's is mica schist dipping 48°
W.; the same, 50° N. 40° W. in contact with a mass of eruptive granite
from ten to fifty rods wide. Bands of mica schist follow, dipping 25°-35°
S. 30° W. Hornblende schist, with a north-westerly dip, succeeds, thirty
feet wide. Mica schist comes in again before reaching the alluvium, dip-
ping 65° N. 60° W. There is not much variation in the position along
this section line.

Fig. 53 presents the strata from the North Thctford bridge to Davison
hill in the north part of Lyme. The Huronian of Lyman aspect occurs
at the bridge, with dolomite near by dipping 70° E. The same rock is
seen at C. F. Carr's, dipping 50° W. The ledges, a fourth of a mile north
of the road, particularly l)ack of M. D. Baxter's, seem to possess the same
inclination. Alluvium conceals the ledges for a mile along the road ; and
the first rock peering above it is hornblende schist, by J. Wise's, dipping

J'i.

XY.

—Sections rN the Connecticut Xalley. —

Talmer Hill.

F/6. .36a. From Palmer Hill through Burnhams Limb Quarry. (See jfp.3t6-7)

Scale of Figures heloTV; { S,'l°^ili}f2T:2SC *■■

an JjticJh.

it
I ^1 Culm Ml

/»>IT£ITE,

Fig. 5'^. Union Village to Bl/ss Pond Fig. 56. Pompanoosuc to Moose Mt.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 385

50° N. 70° W. The same, with talcy seams, occurs in the valley of Clay
brook and at a school-house to the east, with probably no change in the
dip. Ferruginous schists occur next, up a hill. A very tough and ferru-
ginous hornblende rock crops out at Mrs. J. A. Whipple's, dipping 80° N.
W. No outcrops appear in the valley south-east ; but their strike leads
north-easterly to soft talcy schists, resembling hornblende superficially,
with the same position as the last, also, 46° N. 48° W. at J. Converse's.
At J. Hall's comes the narrow band of quartzite alluded to previously.
East of the quartzite, protogene gneiss occurs on Davison hill.

This section differs entirely from that in Fig. 52, a distance of not
over four miles. Between them, on the roads passing Turtle pond, we
have chiefly the soft, green schists. On the Bass Hill road a mica schist
touches the gneiss, by A. English's, with dip of 70° N. 60° W. On the
north-east side of Acorn hill there is a greater resemblance to limestone,
at E. F. Cutting's. It is pyritiferous at J. and H. P. Stetson's.

The next important section is given in Fig. 54, through Lyme and
Thetford. This afforded one of the typical sections of the original Coos
group, as published in the report for 1 870. We find layers of Bethlehem
gneiss and hornblende on the road to Smart's pond, the latter dipping
48° N. 60° W. north from E. Blaisdell's. Just east of the cemetery is a
band of quartzite, which is the eastern branch of the principal range, as
given upon the map. Between the cemetery and saw-mill, I found gneiss
like that common in Enfield village. The quartzite by the mill dips 85°
N. 70° E., and this is east of the crest of the mountainous range. Horn-
blende rock shows itself farther west, having the same position with a
strong band of vitreous quartzite, dipping 55° N. 62° W. The quartzite
seems to lie east of the road, after it bends to the south-west, near A.
W. Clough's ; and there occur, first, epidotic gneiss ; second, hornblende
rock, dipping 15° N. 30° E.; and by P. Allen's, where the road joins the
Canaan branch, limestone dipping 50°-6o° N. 70° W. Westward along
Grant brook extensive outcrops of Bethlehem gneiss show themselves, as
at L. Conant's and A. B. Dimick's ; but the position of the strata is not
easily ascertained. I thought, at my first visit, that Dimick's ledges au-
thorized the figures of 25° N. 48° W. I should say now the position had
better be made to agree with that of the limestone. The rock is unusu-
ally massive, planed down thoroughly by ice action, and simulates granite.

VOL. II. 49

386 STRATIGRAPHICAL GEOLOGY.

This quartzite range seems to lie altogether u23on the ancient gneiss, and
does not connect at all with the mica schists in East Lyme. A band of
mica schist occurs next, about three fourths of a mile wide. There are
no outcrops in the valley; but about a mile north the dip is 70° N. 63°
W. Other observations near by give 60° N. 50° W., both of which may
represent the average position of this formation. It is succeeded by clay
slates, both garnetiferous and stauroliferous. In the eastern part of the
belt, or by a road-crossing of the stream, the dip is 50° N. 50° W. It is
about 30° at another crossing by a tannery. Farther west the dip may
be 35°-40°; and at the western limit of the formation, by A. A. Lam-
phere's, the position is 50° N. 40° W. These slates have thus a much
lower dip than the schists eastward. By D. Fales's and at the church,
just in the edge of the village of Lyme, the western quartzite range crops
out. From here to the river there succeed greenish, soft schists, with a
mineral much resembling chlorite. The dips observed are the following :
About 50° N. 60° W. just north of the village; 50° N. 68° W., slightly
calcareous, at a bridge at the south end of the village ; about the same
at numerous exposures for a mile and a half along Grant brook ; at its
mouth, hard mica schists, 50° N. 40° W. Similar ledges occur between
the brook and Gilbert's bridge over Connecticut river, the rock resem-
bling hornblende schist, though quite soft, and dipping 60° N. 30° W.

In Vermont there is a band of Coos schists, like that in the north part
of Orford, and carrying steatite, near the Norwich line. Two outcrops of
the soapstone are represented upon the map. At the school-house west of
Childs's pond is a quartzite, constituting the west edge of the Coos rocks,
dipping 50° N. W. A band of these schists, in which staurolite and kya-
nite occur prominently, extends southerly over Oak hill till it is covered
by the sand of the Pompanoosuc basin. It is represented as extending
to the west of a hornblende range. West of this there is about a mile
width of the eastern slope of Thetford, underlaid by the characteristic
Huronian schists, dipping, in accordance with some observations in the
Vermont report, 80° E., and, by my own measurement, 80° N. 30° W.
Before reaching Thetford hill, the clay slates succeed, with south-easterly
dips. At Thetford Centre, and generally along the valley of Vershire
brook (or Pompanoosuc river), the rock is a micaceous quartzite, dipping
80° S. 50° E. This was at first placed with the Calciferous mica schist.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 38/

Recent studies in Thetford and Fairlee lead to the opinion that this
quartzite may be the proper equivalent of the quartzite described as a
part of the Coos group, as in Hanover, etc. There is nearly as much
silica in the Thetford as in the Moose Mountain series, the first adding
mica in small proportion to the usual vitreous compound seen east of the
Connecticut. In agreement with this suggestion, I have colored quite a
large area west of the Cambrian slates as belonging to the Coos group.
It is worthy of notice that this formation carries the copper beds of Ver-
shire, and perhaps the pyrites of Copperas hill. It is represented as ex-
tending to meet the ancient gneiss in the west part of Hartland. Its
occurrence at West Hartford and to the south of Quechee village has
been particularly noted. The resemblance between these schists and
specimens from Littleton is very marked.

In the south-west part of Lyme there is a large development of soft,
green schists, whose silicate mineral seems to be talc or chlorite. They
are well seen on the hill road to Hanover, between Grant and Fairfield
brooks. Without close inspection, one would be disposed to say the rock
was hornblende ; — in fact, some of my earlier notes give that name to it.
With it are occasional calcareous seams, so that it presents a resemblance
to the formation about to be described as the Calciferous mica schist in
Lebanon and Cornish ; and I have sometimes thought the Lyme area, as
well as much of the Hanover rock, should be regarded as Calciferous.
The position is uniform over this part of Lyme, except a dip of S. 50° E.
at C. C. Webb's. At N. Kendrick's it is S. 57° W. 70°; at S. Hewe's,
70° N. 80° W.; but farther north not more than 60°. Towards the Han-
over line, the rock becomes considerably ferruginous. At a bend in the
road by A. Smith's, in the north-west part of Hanover, the limestone is
present in the greenish schists, with a north-westerly dip. To the south,
we find the ferruginous schists of Spencer, Lord's, and Prospect or Pin-
neo hills, which have been noticed under the head of Bethlehem group
(P- 353)> and are more likely to belong to the Coos than the other series.

The section in Fig. 55 shows the position of the layers from Bliss pond
and near the south line of Lyme to Union Village, Thetford. The quartz-
ite is wanting east of the pond; and the mica schists join the gneiss with-
out it a little west of J. Tyler's, south of Bear hill. Hornblende schists
are interstratified with them at A. Blood's, standing nearly perpendicular.

388 STRATIGRAPHICAL GEOLOGY.

From the vicinity of the pond is seen an abundance of slate ledges on
the west slope of Bear hill, apparently dipping north-westerly. South of
Bliss pond we find the beginning of the more argillaceous band, dipping
80° N. 50° W. From Fairfield brook the land rises gradually but consid-
erably to Hanover Centre, and consequently afforded an excellent lodging
place for the drift. Hence it is rare to see any ledges near the town line.
West of I. F. Clark's, a mile and a half from Bliss pond, the slate dips
85° N. W. The green schists, referred to above, replace the slates before
we reach the place where the stream crosses the town line. A short dis-
tance west occurs the quartzite; then the schists at S. Hewe's, which
continue westerly until concealed by the alluvium. On the west side we
find chiefly Huronian rocks, with a supposed outcrop of hornblende, and,
possibly, mica schists on Oak hill, by the south line of Thetford. The
Huronian has the anticlinal in it at Union Village, and an overturn east-
erly dip of the slates on the west side of it.

Fig. 56 contains a section from Moose mountain to Connecticut river,
near Pompanoosuc station. At the east end is a porphyritic gneiss, sup-
posed to be a lower member of the Bethlehem group, with a north-west-
erly dip. The Moose Mountain ridge is entirely of the Coos quartzite
dipping 50° N. W. on the section, though usually the angle is greater.
The schists of the Coos group adjacent hold the same position, as do the
clay slates along their eastern border. Hornblende schists are interstrati-
fied with these slates. Boulders of siliceous limestone are plenty at the
west base of the mountain. On the main road to Lyme from Hanover
Centre the slates dip very high N. 60° W., and at their west border are
fairly vertical, with the same strike. Woodward's hill, though mainly of
drift, shows ferruginous schists. Lower down, we find the western range
of quartzite, with its north-westerly dips, and, last of all, the mica schists
overlying them.

Fig. 57 is designed to illustrate the Bethlehem group. Fig. 58 shows
the rocks along the route of Section VI in Hanover. The Bethlehem
gneisses, with a dip of 75° W., are followed by the quartzite similarly
disposed. The Coos mica schist range occupies the steep west slope of
Moose mountain, with a breadth not exceeding half a mile, conforming
essentially with the quartzite, and both perhaps constituting a ridge be-
neath the slates succeeding. It is not certain that the Coos schists recur

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 389

again upon this section, as their place, between the gneiss of Corey hill
and the hornblende schist of Observatory hill, is covered by clay. The
section crossing Craft's hill in Lebanon, which is a very important one,
has already been described upon page 363, Fig. 59.

Fig. 60 shows the position of the rocks along Mascomy river, through
Lebanon to Enfield village. West Lebanon shows hornblende schist in
the Connecticut river. The village is entirely covered by alluvium for a
mile back from the mouth of the Mascomy; and then succeed ledges of
argillo-mica schist, vertical, strike N. 24° W. Massive hornblende comes
next, at the joint crossing of the Mascomy by road and railroad, dijDping
42° N. 63° W. The mica schists of Craft's hill are believed to succeed
on the east, before coming to the Bethlehem area. Hard sienitic ledges
are seen near the scythe factory. These are replaced, near the village of
Lebanon, by protogene gneiss. In the south-east part of the village are
many ledges of mica schist, dipping 60° S. 40° E. Among them are lay-
ers carrying patches of the peculiar variety of fibrous hornblende, called
locally "Bentonite." Other ledges are conglomerates, holding distorted
pebbles. One of them, consisting of a decomposing feldspathic material,
is represented — half the natural size — in another part of this volume. I
have in other publications enlarged upon the distortion of pebbles, and
their bearing upon the subject of metamorphism, and will not say more,
now, than that the shape of this pebble is not a natural one. The upper
end of it has been compressed more than the lower, so that it has been
drawn out, as if plastic, and somewhat bent. Other ledges in the village
show abundant cavities, produced through atmospheric decomposition of
limestone patches. On the hill, also, is a nodular vein of quartz, carrying
hornblende, sometimes fifteen feet thick. South of the village are ledges
thought to dip 75° N. 23° W. Half a mile east of the village a railroad
cut develops similar ledges, thought to stand vertically, with the strike
N. 53° E. This is somewhat like the gneiss of Mill Village, Hanover.
The hills north-east are of mica schist, often considerably ferruginous.
Near the mouth of Stony brook, ledges of ferruginous mica schist, with a
north-east strike, are visible as one rides past them on the cars. The
section crosses next two bands of quartzite, with the intervening argilla-
ceous schists. In Enfield the staurolite mica schists are finely developed.
The railroad cuts through them near the lake, west of the village, where

390 STRATIGRAPHICAL GEOLOGY.

the dip is about 75° easterly. In the west edge of Enfield village the dip
is 72° N. 72° E. The gneiss at the east end of the section has a dip a
few degrees less ; but there is no change of importance in the strike.

The range of mica schists, on the western flank of Moose mountain
through Hanover, is comparatively narrow, but in Enfield it covers four
or five times as much width. There is a bed of magnetic pyrites, with
chalcopyrite, dipping 75° N. 40° W., on the water-shed between Mink
brook and the Mascomy, in the south-west corner of Hanover; and a bed
of the pyrites, said to have been mined once for iron, in the west part of
Enfield, near the lake, dipping northerly. The Shaker villages are situ-
ated mainly upon these schists. At the road turning off southerly from
them there is a ledge of hornblende, dipping 75° N. 75° E. A mile to
the south the mica schist dips 75° N., succeeded by the staurolite layers,
dipping N. 55° E. on top of the hill. I have never seen staurolite crys-
tals more abundant than in the neighborhood of West Enfield post-office.
The layers have an easterly dip. On the surface are large boulders of
siliceous limestone. On an old road to the Lily j^onds, now abandoned,
the mica schists appear, with some conglomeratic beds, dipping due east.
The ledges about here are greatly distorted. It is probable that these
Coos schists rest unconformably upon the gneiss. In the south-west
corner of Enfield the dips are about S. 70° E. After leaving Enfield,
these schists begin to narrow, and in Cornish and Claremont they are
not much broader than in Hanover. The north-west corner of Gran-
tham shows these rocks also. The westerly restriction of the mica
schists is caused by the presence of the same related rocks, interstrati-
fied with siliceous limestone, and described under another head farther
on. The correctness of the line of demarcation, as well as of the distinc-
tion, may be questioned ; but we cannot do better at the present state of
knowledge. The following arc the rocks and their dips from Lebanon
village up the valley of Great brook to Cranberry pond, by the east line
of Plainfield: Mica schists, 75° N. 23° W. for a mile; 50° N. 35° W. at
H. Wood's, on the road crossing the brook ; occasionally the same as far
as East Plainfield, the dip not changing till we reach T. Cutt's on the
Meriden road. It is mostly drift from East Plainfield to school-house
No. 14; west of which are two quartzite bands dipping 52° S. 54° E. By
H. L. Sleeper's the schists dip 48° S. 50° E. Staurolite is abundant

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 39I

between Sleeper's and Cranberry pond, dipping 35° S. 40° E. Near the
pond I have seen some of the Hmestone. Between it and the quartzite
is a band of shining mica schist, which dips 65° S. 40° E. On Blood's
brook the greenish calciferous schists are made to extend to school-house
No. 16; then come the clay slates before alluded to, while all the Coos
schists, both those containing staurolite and others, are confined to the
area between the slates and quartzite of Grantham mountain.

In Cornish, on the road over Croydon mountain (Fig. 62), the stauro-
lite schists overlie the Calciferous, dipping 50° E. into the mountain. On
their western flank, mica schists, without very much staurolite, seem to
be interstratified with quartzite ; and there is a band of the schist on the
very apex of the mountain, at the trigonometrical station. The stauro-
lite schist east of the slate quarry, close by the east line of the town, dips
55° S. 80° E. Taking the road over the south end of Croydon mountain,
from Cornish to Newport, there is a perplexing succession. Leaving the
main Calciferous, with a high south-easterly dip, argillaceous schists may
follow for half a mile, passing into the Calciferous ; then a band of stau-
rolite rock, with the same dip, to O. Fletcher's. For a mile along the
road the genuine Calciferous reappears as far as Wm. C. Poole's, where
large veins of pure white quartz show themselves. These look like large
snow-drifts, from a little distance. From here to the gneiss, mica schist,
holding staurolite crystals in abundance, is the only rock seen. At first
the dip is 28° southerly, then only 15° N. 70° E., with gray sandstones.
Ledges similar to the last are at a charcoal furnace in the edge of New-
port. East of A. Ward's, Croydon, the mica schist of the gneiss group
dips 75° N. 70° E.

The cat hole road in Claremont affords a display of staurolite ledges
similar to those just mentioned at the south end of Croydon mountain.
Leaving clay slates at the road fork between Bald and Green mountains,
they dip 85° N. 5° W. about a quarter of a mile below the summit, and
70° E. at the latter locality. Within a distance of eighty rods the strike
changes ninety degrees. Still farther east on this road, quartzite appears,
and the staurolite rocks cease. This range seems to be pinched out to
the south of Green mountain, but reappears south of Sugar river, a mile
east of Claremont village, and southerly along Quabbinnight brook, with
high easterly dips. This rock widens much in proceeding southerly.

392 STRATIGRAPHICAL GEOLOGY.

In the south part of Lebanon the mica schists fold around the area of
Bethlehem gneiss, and in Fig. 6i we have a section illustrating the fact.
It begins on the west, with a hill of hornblende schist back of S. Water-
man's, dipping 50° N. 85° W. Next will come the continuation of argillo-
mica schists, believed to dip west. At A. Hall's and sons the argillaceous
matter predominates, dipping south-west, with conglomerates. Farther
south, near S. Wood's, are vertical layers of hornblende, with a course
north-south and N. 20° W. By O. S. Martin's the green, soft schists of
the Coos group appear, dipping 80° W. The same occur half a mile east.
The gneiss is not seen upon this road, as it does not extend so far south.
Its central line should strike by R. Wood's. The gneiss is visible from
the road upon the hill north, with a north-westerly dip ; and the outside
of the area corresponds with the upper layer of this rock, as observed
farther north in Lebanon and Hanover. Farther north, by F. Peabody's
and a school-house, the gneiss has the same position. The green schists
east of the axis, by L. Freeman's, dip north-west, and are very fully de-
veloped at J. Hebard's. About three fourths of a mile east of the gneiss,
the same mica schists dip north-west, and still farther east, 75° N. 35° W.
Where a north-south road crosses the east-west one, near W. and E. Kim-
ball's, the same rocks dip N. 25° W. This section illustrates, therefore,
a very clear case of inversion. The gneiss has a monoclinal, north-west-
erly dip, the same with that of the soft, green schists ; but the inclination
is steepest upon the west side. The force of compression has been so
great that one side of the anticlinal has been forced to dip in unison
with and beneath its opposite ; and the overturning has affected the Coos
schists as well as the gneiss. The hornblende does not appear to have
shared in the overturning, as it is not repeated on the east side; but its
course has been made to agree with that of the central axis. The curv-
ing of the newer schists around the gneiss is also illustrated in the strike
of N. 40° W. of the former at T. Wood's, half a mile south of O. S. Mar-
tin's. A north-west course is extremely rare in this vicinity, and its
occurrence here has an important significance.

Coos Slates. We hope to distinguish several areas of slate from the
mica schists upon the map, partly because some portions of them are
with difficulty separated from the Cambrian series. It may prove here-
after that the distinction we have made is untenable ; hence their separa-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 393

tion from the CoiJs schists may enable us in the future readily to assign
them where they belong. As a rule, the Coos slates differ from the Cam-
brian by the occasional presence of staurolite and garnet; by standing at
smaller angles, the latter being very commonly vertical; and by the ab-
sence of auriferous quartz veins. The first area of this kind in the Con-
necticut valley has already been described in Lisbon (p. 318). Next are
two small areas in Piermont. Two others in Orford have been alluded
to, upon page 383, where reference is made to the existence of cleavage
planes distinct from the stratification. The largest one known begins
south of Acorn hill in Lyme, and extends through Hanover and East
Lebanon, being almost the continuation of the Cambrian range from
Springfield, Vt., to Plainfield. This is crossed by sections in Figs. 54,
55' 56' 58, ^nd 60. The smaller areas are all readily referred to the syn-
clinal form, and are believed to be small fragments of a newer scries than
the adjoining schists. This larger area is not so easily disposed of. It
is easy to call its position on the Lyme section (Fig. 54) an anticlinal.
Figs, 55 and 56 show a still better correspondence with the basin struc-
ture. We have more abundant information concerning the region of Fig.
58, along the valley of Mink brook and over Hayes hill in East Hanover.
Passing up Mink brook, we find the gneissic series extending as far as
the first crossing by the road above the Baptist church. The slates suc-
ceeding at the second crossing dip 75° and 60° W., the latter in the road
turning northerly. A few rods higher up, at a small fall, the slates dip
80° W. There and farther along are frequent layers of a slaty conglom-
erate. This must be newer than the ordinary slates, since it is composed
of the ruins of an older series. I have sometimes surmised them to be
as recent as the Helderberg, an impression heightened by the occasional
occurrence of patches superficially resembling corals. At an old mill-
site, at the upper end of a sort of gorge cutting through the glacial drift,
we find similar slates, with conglomerates, standing vertically. There
are bluish quartzites interstratified with the slates at the brook crossing
above the gorge, also vertical. The slates at a road turning northerly to
a school-house, up a large tributary, are slightly plumbaginous and soft.
A quarter of a mile beyond, after passing several slate outcrops without
essential change of position, an interesting dyke of dolerite cuts the
slate at a slight angle. This trap is remarkable for containing perfect
VOL. II. 50

394 STKATIGKArniCAL GEOLOGY.

crystals of labradoritc, some of them two inches long. This is about the
eastern limit of the slate.

If we pass over the hill, directly east from Mill Village, the last of the
Bethlehem series occurs about half a mile up the hill, the rock being
white and ferruginous, and therefore becoming reddish-brown upon ex-
posure. A band of quartz occurs here, such as is found in this gneiss
area in two localities near the river (p. 353.) The dip is 55'''' N. 65^"" E.
Drift conceals the ledges over most of the westerly slope of the hill.
At I. Fellow.s's the .slate runs N. 35° E., and stands on edge. On the
top of the hill the dip is 85'' S. 50'"'' E.; on the eastern slope, near the
eastern edge of the formation, the dip is 73'"-' N. 40"^ W. These observa-
tions do not give much insight into the number or nature of the foldings,
because the dijjs are mostly perpendicular; and such ledges may have
been folded without giving any indication of an axis. By Walker's slate
quarry there are indications of a .synclinal and an anticlinal. This range
may be separated from the other by a narrow band of mica and cuprifer-
ous schist, on the water-shed between Mink brook and Mascomy river.
I find that the observations in the Mink lirook valley show a northerly
strike, while those on the hill are north-easterly. Further search will
show whether this variation is correct, and, if so, whether it is due to the
presence of cleavage planes, or whether it has a deep significance, due
to the occurrence of different formations unconformable to each other.
The western border of these slates, just south of the Hanover line, joins
ferruginous schists, both dipping 80'' S. 43° E. At the slate quarry in
East Lebanon the slates are mostly vertical, with a north-south strike.
Those due east over the Enfield line are inclined at a very high angle to
the east. Back of Cleveland's house the slates are about vertical. On
the hill south, by I. Eastman's, the dips are quite irregular, one observa-
tion being 60'^ N. 20*^ E. That is not a common position; and my notes
speak of a change in the strike of thirty or forty degrees from this within
half a mile, in proceeding southerly. I think there is an anticlinal in
the slates between the two quartz ranges of East Lebanon. There are
several slate outcrops upon Stony brook, which I think dip to the north-
west, but I have preserved no record respecting them. Certainly all the
ledges to the west have that position, while those on Eastman's hill to
the cast dip in the opposite direction.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 395

6. Calcii-erous Mica Schist.

This name is adopted from the Vermont final report. Professor C. B.
Adams called them "Calcareo-mica slates." IVAh the expressions really
ought to be replaced by a geographical designation.

The formation consists of mica schists, micaceous quartzitcs, argilla-
ceous schists, and especially siliceous or bluish micaceous limestones.
The limestone is the most abundant at the north end of the Vermont
deposit, while the mica schists predominate in Massachusetts. The for-
mation is broadest in Caledonia and Orange counties, narrowing nearly
one half as it enters Canada. Below White River junction it divides, the
broadest area running down to Proctorsville, where it terminates, and the
other following the west side of the Connecticut through the state, with
a nearly uniform width, enlarging a little near the Massachu.setts bound-
ary. The strata are less highly inclined in the broadest portions of the
area, and they are much tilted up where the band is the narrowest.

Two areas of the formation occur in New Hampshire. One is in Cole-
brook, Columbia, and Clarksville ; the other is in the present field of de-
scription, extending from the southern part of Lebanon to Charlestown.
The first is isolated ; the second is a part of the great Vermont range,
separated from it by the Connecticut river.

Passing up Blood's brook, from the last of the hornblende rocks to
Meriden, the rocks are mostly soft, greenish schists, commencing near
the mouth of the tributary following down the valley on the west side of
Morgan hill. We find a sandy schist, with the dip 80° N. 30° E., at the
mouth of this stream. About a mile higher up, the greenish schist dips
45° westerly; and the rocks have essentially the same position all the
way to Meriden, save that the angle of inclination is constantly becom-
ing steeper, reaching 75"^ or 80'^. Narrow seams of limestone occur in
the square fronting Kimball Union Academy. The easterly dip begins
just east of the academy; and the rocks may be followed to the clay
slate band near school-house No. 16. The hills to the north of Meriden,
as Batchelder and Morgan, with the Pinnacle in the extreme south part
of Lebanon, are composed of the same formation, the axial line running
from the academy to T. Cutts's, and perhaps to the anticlinal recently

396 STRATIGRAPHICAL GEOLOGY.

spoken of east of Stony brook, as well as to Walker's slate quarry in
south-east Hanover, but in a different formation.

From Meriden to Cornish Flat — four miles — we see the same rock in
abundance, with a south-easterly dip. Bean's, Colby's, Fifield's, Smith's,
and Jordan's hills, and French's ledge in Plainfield, are all of this type of
structure. A northerly projection of the formation, to connect the Plain-
field area with that in North Hartland, would add Prospect and Home
hills to the list. On the first there is a considerable band of a grey dolo-
mitic limestone, unlike the usual variety of this rock. I suppose it to be
the same with that analyzed by Jackson, giving, of siliceous matter, 25;
peroxide of iron, 2.8; carbonate of lime, 23.8; carbonate of magnesia,
46.6=98.2. We have traced it through Prospect hill, about three quar-
ters of a mile. It may extend to some of the localities mentioned by
Jackson south of the "Plain." This rock is unlike anything else in the
neighborhood, and we have had suggestions of its reference both to the
Huronian and to the Helderberg. It is on the line of the Huronian of
Willard's ledge. There is another outcrop of similar material south of
A. Bugbee's; and Mr. W. H. Daniels thinks its continuation may be
seen on the west slope of Black hill. The question of age cannot be
decided without further study.

Mr. Huntington has carefully studied the rocks of Prospect hill, and
presents us with the following additional statement respecting them:

"Just below D. Burnap's there is a synclinal in the hard, green schist,
with strike north and south. The limestone crosses the road fifteen or
twenty rods below Burnap's, and dips N. 50° W. 64°. Directly west a
quarter of a mile, the strike is nearly east and west; three fourths of the
way to A. D. Reed's the strike is nearly north and south. Above Bur-
nap's the green schist is strangely contorted. On the hill, a little west
of north from Burnap's, a whitish mica schist dips S. 80° E. 75°, but it
is bent very much in places. South-west of A. K. Reed's, a green schist
dips S. E. 72°.

"The limestone north of Burnap's has a strike nearly north and south,
with westerly dip. There is no absolute proof that this limestone is Hel-
derberg. The surrounding rocks certainly are Huronian."

Along the Connecticut river, the Calciferous ledges extend to Beaver
brook, the first seen there dipping easterly, and being quite argillaceous.

Tn^^rrE 7CVI.

-Sections in the Connecticut Valley-

9 ^

Gneiss

Ft6.$7. CoNN.f^..To BaftjstCh. Fig. 58. Leoyahd BhidgBj Hanove.r , to Moose Mt.

/5^ HuRONiAN,^- DioriteS, "r* Etc

.^- fig ^^

Fig. 59. White River Village, Vermont^, to Crafts Hill, Lebanon.

^11 ^j^i

F1G.6O. Along Mascomy River.

Fig. 67 /n South Part of Lebanoh

Fig. 62. From Windsor, Vermont, to Croyoo/v Mount-ain.

i

^ 3arl>ex- IvTt

^HUR O M IAN.

t

I

. ^ Trisback Hill. ^ * Bethlehe(v»

I" i* Cauciferou& Mica Schist.^ Clay Slate. J Gneiss.

F/G 6S. Section through C laremont.

Vertical, scale of Fig^,. .S7, 58, 60, 61, and 63 - 2.000 Fbet to an Inch; of Fiq.33 =12oo

Feet; At^D or Fid. 62 =-3000 •• » " /< .
HafiizoNTAL Scale of Fics. 57,^)8, 6'0, and GI = 5;^ Milb^ ro an //vchj of F/g.5& "l Mtcej

AND OF Fi6S.G'2 Afio6'3 ~ l^z Miles '■ " " •

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 397

On the west slope of Home hill are several prominent veins of quartz,
perhaps the continuation of those carrying a little argentiferous galena
at the Ascutney Mining Company's property in Hartland. These occur
at the house of Capt. C. Gallup. Near the old Hart's Island bridge the
schists dip south of east, A mile south-west of the plain the dip is 35° S.
E., and 30° S. W. at A. K. Reed's, two miles north. The most northern
outcrops of this rock on the hill road north from the plain are at L. Wil-
liams's, on the west side of Prospect hill.

Cornish is nearly all underlaid by this formation; and the character-
istic topographical features of a limestone country are well exhibited
both here and in Plainfield. This consists in rounded steep hills and
deep valleys, everywhere fertile. Along Connecticut river the normal
dip is easterly. At E. Pike's, at the most north-western road fork in
the town, the dip is 75'' south-east. At the crossing of Blow-me-down
brook, near its mouth, we see dips in both directions, making an anticli-
nal. The westerly dip is shown nearly a mile farther south, at Capt. D.
D. Freeman's, and in small, rocky islands in the river. Near Windsor
bridge the dip somewhat south of east prevails to the exclusion of the
other, save as it may exist unseen beneath the waters of the Connecticut,
The strike carries the easterly dip in such a way that we may believe in
the existence of an anticlinal certainly two miles long, and lying near a
Huronian ridge (Dingleton hill, p. 364). The westerly crowding of the
older ridge would naturally produce this arching of the strata.

The rest of Section V, through the central part of Cornish (Fig. 62),
gives a good idea of the position of these rocks, the dip being mostly in
an easterly direction. At the east edge of the formation the schists dip
about 57° S. 30° E. This is on the east side of Parsonage hill; and the
dip 60° S. 50° E. occurs next, the strata being much crumpled and de-
cayed. At the town farm and hall the limestone is abundant, and the
dip is 57° S. 40° E, Near the Methodist church, on reaching Bryant's
brook, there are bands of a decomposing, fine-grained white granite,
dipping 85° N. 30° W. At the school-house No. 11, hornblende schist
occurs, dipping 55° N. 70° W. East of a cemetery it is more massive,
and is properly a diorite. West of this, near the saw- and grist-mills,
the Calciferous schists recur, crumpled, and dip 57° E. This is just east
of the Dingleton Hill Huronian ridge. Two faults probably exist here,

398 STRATIGRAPHICAL GEOLOGY,

SO as to account for the presence of this segment of mica schist in the
midst of Huronian ledges. We have reason to beheve the mica schist
possesses the anticlinal form at its recurrence in Connecticut river. On
the west bank of the river in Windsor the Calciferous group is present,
with its normal appearance and dip of 55° S. 80° E. It continues up on
to the flank of Mt. Ascutney. At a quarry at the north-east base of the
mountain the dip is 80° E., where the rock is quite argillaceous. At the
crossing of Mill brook the rock is micaceous quartzite, like that of Fairlee
and the Ely copper mine. The eastern part of Weathersfield shows the
Calciferous series, with dips like those in Windsor. The south branch of
Bryant's brook, between Kenyon and Wellman's hills in Cornish, shows
mica schist, chiefly, with a few beds of limestone, and positions corre-
sponding with those along the line of the section. The same general
statement will apply to much of the northern part of Claremont west of
Bald mountain. At the Lottery bridge over Sugar river, very near the
Connecticut and in the valley between two Huronian masses, the lime-
stone layers show themselves, dipping on the average 50° W.; but the
layers are badly doubled up, as would naturally be expected from their
position between older rocks, and also the neighborhood of Mt. Ascut-
ney, There is a large precipitous ledge of Calciferous rocks at the high
railroad bridge over Sugar river, dipping easterly.

Fig. 63 shows a section along Sugar river, in Claremont, where details
have been carefully worked out. At the west end is the Huronian
Barber's mountain, with its irregularities, perhaps an inverted anticlinal.
The Calciferous mica schist shows a well marked anticlinal in Trisback
hill ; and the facts are best explained by supposing this rock to rest upon
the dolomitic and sandy schists to the west. The axis lies just to the
west of the mass of the hill, the western dip being 50° S. 75° W. On
the east side limestone is unusually abundant. Near the mouth of Red-
water brook the dip is east. On arriving at the edge of Claremont village,
at the lowest fall of water in Sugar river, where two mills are located, the
argillaceous variety of the formation dips 60° S. 70° E. At the dam of
the paper-mill the dip is 56° S. 6^° E.; and the rock weathers like the
average of this formation in Vermont. At the bridge just above, the
strikes N. 20° E,, N. 10° E., and N. 27° E. were measured. Above this
bridge the strike N. 20° E. was observed, and also at a dam near two

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT, 399

large mills. Near the first dam below the upper bridge the dip is 6i°
S. 70° E. This is an excellent exposure of the soft, green schists, like
those described heretofore as belonging to the Coos group, with many
strings of white lime interstratified. At the bridge itself, the schists dip
6S° S. ^8° E. Above this the clay slates, with high easterly dips, succeed,
followed by quartzite and gneiss, whose details of position have been de-
scribed heretofore with sufficient minuteness. Trips to Cornish, over any
of the roads leading there from Claremont village, show occasional good
exposures of the soft, green schists, with easterly dips. They also occur
to the south-west, just encroaching upon the borders of Charlestown.
Near school-house No. 9 they dip about 65° S. 70° E. On the north-
west flank of Bible hill the dip is 63° S. 48° E. At W. Clark's a tougher
variety of the rock, making a ridge, dips 59° S. 42° E. At the edge of
the formation, near N. Stone's, the strike is N. 30° E., and the strata
nearly perpendicular. About school-house No. 16 the green schists are
very abundant. They likewise occur in many excavations for building
purposes within the limits of Claremont village. A review of the dips
about Claremont would indicate an anticlinal and a synclinal, the latter
inverted, in this area of Calciferous mica schist. The rock is believed to
be newer than either the schists on the west or the slates on the east
side of it in Claremont.

On comparing together the positions of axes, it seems not improbable
that the Trisback anticlinal may run northerly to join that in the dis-
placed segment by the mills in Cornish, and thence north-easterly past
Meriden to East Lebanon and Hanover into another formation. The
direction of the axis being more easterly than that of the strata, it runs
off into the adjacent formations beyond East Plainfield. A comparison
of the dips with those in the gneiss of Enfield and Canaan, in the next
chapter, will show whether this line of elevation also affected the older
gneisses, and should therefore be regarded as occasioned by a very pow-
erful earth movement.

T/ie Calciferous m Vermont. Hardly any group of strata occupies
more space than this in Vermont ; and as our thirteen sections across
that state, the continuation of those measured in New Hampshire, have
recently been reexamined, it seems proper briefly to refer to what has
been learned there respecting their formation.

400 STRATIGRAPHICAL GEOLOGY.

On Section I, in the eastern part of the area, an anticHnal brings up
gneiss and hornblende schist. The same is true in Massachusetts to the
south, and at West Brattleboro', on Section II, to the north. This is
the same with the granite of Black mountain in Dummerston. The same
three sections allow certainly of a synclinal west of this anticlinal, nar-
rowing on Section II. It is known to extend as far north as New Fane
and Dummerston. On our revised Section III, in Westminster, observa-
tions are wanting on this formation ; but in Section IV, of Vermont, the
dip is altogether monoclinal, with the average easterly dip of 60°. This
being the narrowest part of the formation, I calculated the thickness here,
in the report upon the geology of Vermont,* finding it to be 4800 feet.
It was presumed the narrowness of the band might indicate its true thick-
ness, without any repetition, such as occurs almost everywhere else. Es-
sentially the same state of things is believed to occur on our No. IV in
Springfield. Section V crosses Mt. Ascutney, an eruptive mass in the
midst of the mica schist, and therefore teaches nothing concerning this
rock. I believe the strata on both sides of Ascutney are monoclinal, and
dip easterly. But we have stated evidence of the existence of two anti-
clinals in this rock on Section V in Cornish, besides the possible inverted
synclinal to the east of the last ridge. The western arm of this formation
is crossed by this section in Reading, where it may be a synclinal of lim-
ited extent.

Section VI first gives us an idea of this formation where it is very
broad. There would seem to be a synclinal of this schist in Hartford, —
clay slate to the east and a Coos micaceous quartzite to the west, — the
same range with that holding the copper and pyrrhotite ores to the north
at Copperas hill. It is very likely a fault occurs west of this cjuartzite.
The Calciferous group following in Pomfret is largely composed of lime-
stone as far as to the argillaceous schists in Barnard marking the western
limit of the formation. In this area there arc two anticlinals and three
synclinals, the last joining a faulted fragment. Section VII shows the
Coos quartzite, extending as far as the eastern part of Strafford, occupy-
ing a place between the clay slate, which usually adjoins the Calciferous,
and the Calciferous itself, with a uniform, probably inverted easterly dip.
A fault may, perhaps, separate it from the Calciferous, which consists of

*VoI. ii,p. 617.

GEOLOGY OF 1 HE CONNECTICUT VALLEY DISTRICT. 4OI

an inverted synclinal to the cast of Strafford Centre ; a normal anticlinal
in the west part of the town ; a synclinal in South Tunbridge ; an anticli-
nal, followed by a synclinal, beneath argillaceous schist; and an anticlinal
again before touching the western band of Cambrian slate at Bethel. On
Section VIII there may be a band of Coos rocks in Newbury, consisting
of argillaceous seams much twisted and devoid of limestone, in a possi-
ble anticlinal aspect. The Calciferous group succeeding is mostly lime-
stone; and four or five duplications may be made out in it before coming
to the central hill in Washington, where we find a very low easterly dip
of massive limestones. These supposed duplications are monoclinal, with
various degrees of dip. From this central range the dips are all westerly
to the slates of Northfield, with certainly indications of three axes, occa-
sioned by different inclinations of the strata. As originally published,
this section seemed to be one gigantic anticlinal; but our repeated ob-
servations indicate the existence of several closely pressed folds upon
both sides of the centre, and this middle point may be the newest part
of the formation. Sections V-VIII were carefully resurveyed by me in
1875, and hence are understood in greater detail than before.

Section IX loses its central hill of limestone, and its place is taken by
an enormous mass of granite, perhaps erupted in a period subsequent to
the deposition of the limestone. On the west side of it is a satisfactory
synclinal overturn at its junction with the western band of Huronian.
On the east the dips are monoclinal, probably all overturned to the east.
Section X is more singular still. Most of the area is a high table-land
of limestone, the recurrence of the Washington ridge ; and at both sides
there is a narrow synclinal, closely pressed and adjoining Cambrian slates.
Section XI shows the central plateau, disturbed and broken in two by
eruptive granite. On the east the inclination is gentle towards the rising
sun ; and at East Burke the crowding westerly of the older rocks has
inverted the limestones to dip high to the west, and thus show a syn-
clinal basin. West of the granite are two regularly formed basins, sepa-
rated by a symmetrical anticlinal. This is succeeded by a smaller por-
tion of the schist caught in eruptive granite adjacent to the Cambrian
slates. Section XII gives us an anticlinal in Brighton, elevated appar-
ently by an upward push of granite. It joins an older granite directly
on the east side, as the slates usually bordering it farther south have
VOL. II. 51

402 STRATIGRAPHICAL GEOLOGY.

disappeared. West of this anticlinal there is another mass of granite,
which seems to mark a fold in the Calciferons. To the westward the dip
is altogether westerly; and three or four supposed overturn synclinals
appear there. The dips in Section XIII, naturally protracted, give us
the fan-shaped structure, which may be easily resolved into a double
synclinal basin. The synclinal form appears yet more distinctly after
passing into Canada. I do not present any diagram in the text to illus-
trate these sections, hoping that the way may be opened to publish in
the Atlas the entire group of them as they cross the two states of Ver-
mont and New Hampshire. Their publication is not authorized at the
time of writing this brief notice of them.

In brief, all the sections across this Calciferous formation can be best
interpreted by constructing them upon the theory of their more recent
age than the adjoining bands of Huronian, — one, in the Connecticut val-
ley, and the other, skirting the east base of the Green Mountains. This
is also the position assigned to the continuation of the limestones into
Canada by Sir W. E. Logan. He did not speak so clearly of the clay
slate band, not separating it from the limestone, and calling them both
by the indeterminate name of Gaspe. If the first position assumed is
sound, that the limestone or Calciferous overlies the Huronian, then it
will easily follow that the slates will come between them in age, as they
do in territorial distribution, and are to be called Cambrian, Another
view might be taken of the westerly band. It might be considered as a
narrow, closely pressed Helderberg synclinal, inasmuch as Upper Hel-
derberg fossils occur in somewhat similar layers on their course at Lake
Memphremagog. It would be better to say that the band belongs to the
Cambrian series ; but in Helderberg times, when this entire northern re-
gion was submerged, there was a subsequent slaty deposit of that later
age directly over and derived by disintegration from the Cambrian, The
same supposition may be extended to the eastern band, as all observers
so far have agreed that this series underlies the Bcrnardston Helderberg.
These slates make up the mass of West mountain, situated to the west
of the village, underlying the Helderberg limestones.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 403

7. The Ascutney Area.

Mt. Ascutney is the highest mountain immediately adjoining the Con-
necticut river in any part of its course. The nearest one to it is Bovvback,
in Stratford, which falls short of it about two hundred feet. Ascutney is
also more conspicuous than any other mountain near the river, since it
rises from a lower plain. It is essentially a cone, nearly three thousand
feet higher than the river at its eastern base, only three miles distant ;
and there is a small subordinate cone on the west. The principal cone
is composed of eruptive granitic material. The smaller mountain is in
part eruptive, but is mainly made up of gneiss of Eozoic times, probably
older than Montalban. The larger mountain rises from a fissure cutting
directly across the Calciferous mica schist, indurating but not greatly dis-
arranging the course of the strata.

Our map shows a strip of gneiss in Vermont, extending from Marl-
boro', or Athens, to Hartland. This has a narrow band of hornblende
schist upon both sides of it. We should have been glad to study it
carefully, but it lies outside of our field of labor. It is thought to agree
with the gneiss of our Lake period, while some parts of it resemble the
Montalban. Its environment by the hornblende suggests its eciuivalency
with the Bethlehem group of Cheshire county, where a similar concen-
tricity is displayed. Upon Section V we find a very distinct anticlinal in
the south part of Reading, just west of Little Ascutney. It is our theory
that that range of gneiss is a repetition of the Green Mountain rock, and
that both are older than the intermediate Huronian. The Ascutney rocks
are situated on the east side of the northern part of this ancient gneissic
range; and the eruptive portions cut across both this older rock and the
adjacent Calciferous mica schist. A careful delineation of the boundary
between these two formations, upon both sides of the eruptive mass, indi-
cates the course to be the same, and to have been continuous before the
eruption. The erupted materials came from an east and west rent in the
strata ; and, in consequence of the abundant liberation of heat at the time
of their protrusion, the character of the limestone and other rocks adja-
cent to it has been changed.

There is reason to believe the nucleus of Little Ascutney belongs to a
period distinct from either the Lake gneiss or the eruptive age. There

404 STRATIGRAPHICAL GEOLOGY.

is a conglomerate upon its summit, associated with porpliyry, both of
whicli are unhke anything in the neighborhood, while slightly similar to
certain ledges in the White Mountain district. The phenomena upon
this mountain have been described in the Vermont report (vol. ii, pp.
565, 624) as illustrations of the alteration of conglomerate into porphyry
and granite. It is stated that

On the top, just where the southern slope begins, masses of a conglomerate of a
decided character, several feet and even rods wide, appear on the side of porphyry
and granite. All traces of stratification in the conglomerate are lost, and it passes,
first, into an imperfect porphyry, and this into granite, without hornblende, in the
same continuous mass, without any kind of a divisional plane between them. Where
the conglomerate is least altered, it is made up almost entirely of quartz pebbles and a
larger amount of laminated grits and slate, the fragments rounded somewhat, and the
cement in small quantity. It is easy to see that a metamorphosis has taken place in
all the conglomerates, and some of the pebbles might even be called mica schist. In
the cement, also, we sometimes see facets of feldspar. In short, it is easy to believe
that the process of change need only to be carried further to produce sienite, por-
phyry, or granite. One cannot resist the conviction that the granite rocks of this
mountain are nothing more than conglomerate melted down and crystallized, or, at
least, that such was the origin of a part of them. [Page 566.]

The basis of this theory rests largely upon the supposition that these
three kinds of rock occur along the line of strike. A revisit to the
locality in 1872 shows that these three sorts of rock occupy different
layers, the strike being N. 80° W., or nearly at right angles to the course
common in the neighborhood. The ledge exposure showing them all is
continuous. I do not see why the change in the direction of the strike
should have been overlooked in 1858. The fact of this change in the
strike, together with a variation in the nature of the rock material, sug-
gests whether we have not here the relic of a different formation, resting
upon the gneiss. We shall see presently that it extends farther east than
the gneiss, bordering the granite of the larger mountain. Little As-
cutney has two peaks. The more northerly one is close by Mill river
in West Windsor; the other, which is higher, is in Weathersfield, over-
looking Black river. I will describe the rocks as they occur on a line
from about the house of Mrs. T. Piper in Weathersfield, — the southern
foot of the mountain, — over the two peaks towards Brownsville in West
Windsor. The south slope is quite steep, and furnishes several outcrops

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 405

of ancient crystalline gneiss. Near the road the dip is 60° N. 52° W.;
forty rods north, it is 25° N.; fifty rods, 40° S. 50° E.; seventy rods, 45°
S. 58° E. Next to the conglomerate the gneiss dips 25° N. 70^ E. The
conglomerate dips N. 10° E., perhaps 50°. The pebbles consist of gneiss,
hornblendic gneiss, greenish quartzite, hard mica schist, compact feldspar,
and transparent quartz. Most of these are readily referable to the gneiss
near by for their origin. The greenish quartzites may have come from
the Huronian. The cement is feldspathic; but there is nothing, so far as
examined, that appears to have been derived from the Calciferous. Next
occurs felsite, in a variety of aspects. One is that of a dark, compact
variety, with whitish dots, showing pebbles only where it is weathered.
Another has a slightly trachytic aspect, of gray color, having crystalline
bunches scattered through a fine-grained paste sprinkled or peppered
with small black grains. Other portions have black hornblendic frag-
ments disseminated through them. Both these varieties contain crystal-
line bunches, having one mineral inside of another. I have specimens of
hornstone from this vicinity, but do not remember how abundant it may
be. Between the two peaks the ledges are chiefiy common and horn-
blendic granites. There is a junction of granite with a ferruginous rock
at the summit of the more northern peak, the line of union running north
and south. In the road between the two Ascutneys the rock is mostly
sienitic. Following the lower edge of the sienite easterly, we find a nar-
row band of gneiss extending beyond the point where the west line of
the mica schist would naturally pass. I should judge this might extend
three quarters of a mile east of the natural boundary line. The gneiss
to the east and south of Little Ascutney dips to the east. The edge
between the sienite and gneiss is quite irregular on the north and west
sides.

The union of the sienite of the larger mountain with the calcareous
rocks is full of interest. The phenomena clearly establish the fact that
the limestones change their character in approaching the sienite, and
that their strike is not affected essentially. The strata dip at a very
high angle to the east, and cease abruptly on reaching the granitic rock.
It follows, that the granitic rock has been protruded through a fissure in
the Calciferous mica schist, and the accompanying heat and other agen-
cies have indurated the limestones, perhaps inducing in them the forma-

406 STRATIGRAPHICAL GEOLOGY.

tion of crystals of scapolite. The resultant rock rings like metal when
struck with a hammer. The width of the space between the two walls
of schist is two miles. The length of the rent, — that is, of the erupted
mass, — is five and one third miles. The direction is a little south of east.
It is very possible that a portion of t^e rock removed from this enormous
gap may have been absorbed or melted by the sienite; but most of the
opening must have originated from the forcible rending apart of the
strata. The edges of the schist next the sienite, wherever favorably
exposed for observation, show enormous granitic veins of a fine-grained
variety branching out from the larger mass of sienite. One is reminded
of the corresponding phenomena described upon Mt. Webster (p. 175).
It is interesting to know that these branching veins are usually finer
grained than the masses from which they proceed.

In a small valley on the north-west side of the mountain, opening tow-
ards Brownsville, the limestones dip 75° S. 80° E., and abut vertically
against the sienite. Similar facts were observed in a valley on the south-
west side, the dip of the strata being 44° N. 50° E. In the precipice
here may be seen a granite vein sixty feet high and ten rods wide. In
another valley farther east the limestone and granite join each other
along a vertical line.

Along the path up the north-east side we find the indurated calcareous
slate, about five hundred feet above the place of leaving the carriage-road,
dipping 40° E. The texture of the sienite up this path is usually some-
what coarse, the crystalline debris resembling gravel. The masses are not
so coarse, however, as those of the Conway granite in the White Moun-
tain district. On the very summit the hornblende is scanty, quartz is
wanting, and the rock is mostly a fine-grained crystalline felsite. The
rock of the mountain almost always carries some mica, so that hand
specimens may be procured of genuine granite. Of other granitic rocks
in our field of labor, the Chocorua aggregate is the most like that of As-
cutney. The conglomerate of the smaller mountain might be compared
with the Franconia breccia.

Our final conclusion from the above facts, respecting the age of the
mountain, is, that there must have been an Eozoic foundation for it be-
fore the production of the limestones, a hill branching off from the great
gneissic range to the west. Subsequently the Calciferous mica schist

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 407

covered up the first formed hummocks. Still later, the force elevating
the calcareous schists showed itself; and, perhaps in conjunction with it,
came the outburst of sienite constituting the principal mass of the two
mountains. This was the proper epoch of the eruption of this mountain
mass. In this respect it agrees with the supposed age of such mountains
as Pequawket, and perhaps the whole series of elevations composed of
Chocorua granite.

In the Geology of Vermont {vol. i, p. 225) my father presents the theory
that the adjacent mica schists must once have existed upon both sides of
the erupted mass of Mt. Ascutney, at least to equal it in height. If the
sienite were once in a melted condition, it would require walls of schis-
tose rock to keep it in place, and thus prevent its flowage over the sur-
rounding county. He presented this theory in order to illustrate the fact
of enormous erosions by atmospheric agents along the Connecticut val-
ley. Other authors would not say this granitic rock had been melted,
like lava, but that it was formed under a pressure equal to ten thousand
or twelve thousand feet of strata. According to either view, the argu-
ment for an enormous amount of erosion would hold good.

We have been unable as yet to prepare our usual "specimen map" of
this second section of the Connecticut valley, together with a catalogue
of the rocks obtained for the museum, upon which our descriptions are
based. Should the map and catalogue be presented, they will be found,
with the corresponding descriptions of the two southern sections of the
Connecticut valley, at the close of this chapter.

408 STRATIGRAPPIICAL GEOLOGY.

GEOLOGY OF THE CONNECTICUT VALLEY BETWEEN CLAREMONT
AND HINSDALE, INCLUDING THE COOS OUARTZITE ON THE EAST-
ERN BORDER OF THE MERRIMACK TOPOGRAPHICAL DISTRICT.

BY J. H. HUNTINGTON.

General Features.

While in general the hills approach very near the river, there are
localities where broad meadows extend for a considerable distance on
either side. Usually, however, where an interval is found on one side
of the river, on the side opposite the hills are often abrupt and near the
river, but very frequently it is the case that the hills are very near on
both sides ; and thus we have the varying scenery that is the charm of
the Connecticut valley.

Just below North Charlestown the quartzite hills approach the river
on both sides. Rattlesnake hill, with its nearly vertical quartzite, and
opposite in Springfield the same rock on Skitchawang mountain, forms
a high, precipitous bluff. East of the road south of Rattlesnake hill the
country rises quite abruptly into a high, plateau-like area, then descends
into the valley of Winter brook, but rises immediately on the east border
of Charlestown into Perry mountain. South of Beaver brook we have in
part a terrace plain, but this is broken by the quartzite ridge of Oak hill,
which is cut by Mill brook, and then rises again in the ridge directly east
of the village of Charlestown. To the south-east there is no marked
elevated area, except Sam's hill. Going east from the village there is a
gradual rise until the country reaches the general height of 1300 feet in
Acworth. In Vermont, west of Charlestown, the country is elevated and
broken. Between Charlestown village and South Charlestown the mead-
ows extend a considerable distance from the river; but the hills approach
the river again, and Kilburn peak rises abruptly opposite ]3ellows Falls.

From l^cllows Falls to Brattlcboro' the valley is narrower than it is
either north or south ; and, since the sides of the valley are abrupt, the
terraces extend only a short distance from the river. South of Kilburn
peak the country rises from the river in broken, undulating ridges; those
on the east side increase in height southward until they culminate in

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 4O9

Mt. Wantastiquit, opposite Brattleboro'. Southward the valley is much
broader, but still it is bordered by high ridges, those in Vermont being
near the river. So far as the general features of the country are con-
cerned, they differ very little, as the rocks change. Skitchawaug moun-
tain is quartz-conglomerate. Kilburn peak is gneiss, and Wantastiquit
is mostly argillaceous schist or slate ; yet Skitchawaug, as seen from the
west, differs very little from Kilburn peak as seen from the east, or Wan-
tastiquit as seen from the same direction. The area of country in which
the rocks are here described begins with the north lines of Charlestown
and Unity, and extends southward to Hinsdale. The line limiting it on
the east runs a few rods east of Unity Centre, and southward just east of
Acworth Centre, through Alstead, diagonally, the south-east part of Wal-
pole, and through Westmoreland and Chesterfield. The gneiss of Kilburn
peak is an island surrounded by newer rocks. In Westmoreland the east
line extends westward nearly to the Connecticut, but in Chesterfield it
turns eastward to a point east of Factoryville, whence it extends south-
ward to the state line. The rocks in Vermont immediately along the
river will also be noticed.

The rocks belong chiefly to the Coos group, but, considering the large
extent of country, there are not many different kinds. Besides the rocks
of the Coos group, we have a few that belong to the older formations.
The following is the order in which the rocks occur, beginning with the
lowest: I. Bethlehem gneiss. 2. Gneisses of the Montalban series. 3.
Huronian. 4. Coos quartzites. 5. Coos slates and schists. 6. Calcifer-
ous mica schist. 7. Eruptive granite.

I. Bethlehem Gneiss.

The Bethlehem gneiss does not differ essentially from that found in
the northern part of the state. The feldspar is generally flesh-colored,
and it contains a greenish mineral, probably chlorite, while associated
with it here and in places in the topographical area east there is a very
marked band of quartz. The principal outcrop is on Quimby hill in
Unity, though it extends across the valley west, and appears on the east-
ern slope of the hill near E. T. Bailey's, and connects with that in the
east part of Claremont, It can be seen in the south-west part of the
town, near M. Johnson's, and it is probably continuous from Quimby hill

VOL. IL 52

410 STRATIGRAPHICAL GEOLOGY.

southward to this point. It resembles in shape the areas in Hanover and
Lyme, and, Hke that in the latter town, it is surrounded by newer rocks.

2. MONTALBAN SeRIES.

The rocks that appear to belong to this series are found in the south-
west part of Charlestown and in the north-west part of Walpole. In
some locahties we have a gneiss that resembles the common or Lake
gneiss, but still it is not identical with it, while elsewhere the rocks can-
not be distinguished from those we have referred to the Montalban series.
If the whole of the rocks of this area do not belong to the latter series,
the more compact variety of gneiss being the lower division, it would
naturally be classed with the Lake gneiss, — yet I suppose they all belong
to the Montalban series. Like many other outcrops of rock in the state,
it is a somewhat oblong area, nearly as wide as it is long, and presents
rounded contours, both in its northern and southern prolongations,
though it is more abrupt on the south than on the north. It begins in
the hills north-east of South Charlestown, and widens so that opposite
Langdon Centre it extends over a space of two and three fourths miles ;
but in it there is included a band of hornblende gneiss. From its out-
crop on Saxton's river to Paper Mill Village, it is not far from ten miles
in width. It has its southern limit about a mile and a half south of
Drewsville. The rock varies considerably in texture. Along its northern
border, on the west to its southern outcrop on Saxton's river, through
Langdon, and at Paper Mill Village, we find the variety that is coarser
in texture, and it is like some of the common or Lake gneiss of the At-
lantic system. This rock, however, at the falls carries fibrolite, which is
unknown in the common gneiss. Going from South Charlestown tow-
ards the south-east, through the pastures that slope to the north, there
are many ledges of the gneiss that have segregated veins; and in the
coarse we find a band two feet wide of the finer variety, like that at Cold
River bridge.

The points where this rock comes in contact with those that surround
it are all concealed by drift. At Langdon Centre we have the gneiss at
the school-house, and a mica schist in front of the church. The gneiss
has an easterly and the schist a westerly dip, showing clearly their un-
conformability. At Bellows Falls, in the gneiss beside the fibrolite, there

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 4 II

are wavelite and prehnite. At Drewsville, in the river above the bridge,
there are small but very fine crystals of prehnite in narrow veins in the
gneiss. The following figures show the dip of the gneiss to be exceed-
ingly variable: East of J. Milliken's, Charlestown, S. 50° E. 64°; at E.
Osgood's, S. 36° W. 50°; at B. Sartwell's, E. 25°. On Porter hill, Lang-
don, S. 45° W. 30°. At grist-mill in Alstead (Paper Mill Village), S. 70°
W. 24°; below Paper Mill Village, N. 23° W. 24°; at J. Chandler's, N. 40°
E. 45°. In Drewsville, N. 30° E. — variable; in Walpole, at the mouth of
Mountain brook, N. 12° E. 38°; at Cold River bridge, N, 35°; between
Cold River Bridge and Bellows Falls, E. 35° to 60°; at Bellows Falls, by
railroad bridge, N. 50° W. 62°.

3. HuRONiAN Rocks.

These rocks, if they appear in this area, are very limited in extent.
In Vermont, however, opposite Charlestown, we find a few that undoubt-
edly belong to this group. They begin on the west side of Skitchawaug
mountain, and south of the Black river they probably extend to the Con-
necticut, and form a narrow band along the river to a point just south of
Saxton's river. The band probably turns to the east and extends around
the Montalban gneiss, since there is a limited outcrop in Walpole on the
railroad some eighty rods south of Cold River bridge. The first outcrop
west of the Cheshire bridge is a greenish chloritic schist, with the strata
nearly vertical; but south in Rockingham we also have dark siliceous
schists, and these are the prevailing rocks immediately west of Bellows
Falls. In the north-east corner of Westminster, on Saxton's river where
there were formerly some mills, the rocks are probably Huronian. On
the hill half a mile south-east of this we have hard siliceous schists, and
with these there is a peculiar breccia. This is probably near the south-
ern limit of the Huronian rocks in this section of Vermont,

Nearly opposite this point in Walpole we have a dark siliceous schist,
with a northerly dip ; but where the rock is cut by the railroad south of
Cold River bridge we have a distinct conglomerate. These rocks are
very limited, and are the only ones that we have referred to the Huro-
nian.

412 STRATIGRAPHICAL GEOLOGY.

4. The Coos Quartzites.

These rocks pass on the one hand into quartz-schists, and on the
other into quartz-conglomerates. The chief constituents of the latter
are quartz and quartzite pebbles, from those that are very small to those
that are a foot or more in their longest diameter. In some places the
pebbles are very distinct, while elsewhere it requires weathering to show
that the rock is not a common quartzite. Although in a very few places
the pebbles are nearly round, there are many localities where they are
oblong, and sometimes they appear to be elongated and bent. In the
north part of Springfield, Vt., on Rattlesnake hill, there are a few argilla-
ceous pebbles, probably derived from the Cambrian slates.

In this area there are two distinct bands of the Coos quartzites. One
is in the immediate valley of the Connecticut ; the other is to the east in
Unity, and is an extension southward of the main band that has its origin
in Landaff.

The Western Band.

The most northern outcrop of the quartz-conglomerate in the section
we are describing is on Rattlesnake hill in Springfield, Vt., and here it
appears to be an isolated area. It is composed chiefly of flattened quartz
pebbles. There are, besides, a few fragments of slate ; and the strata dip
east at a high angle. The rock on both sides is calciferous mica schist.
South along the Connecticut river the Skitchawaug mountain, extending
from the first school-house in Springfield almost to the Cheshire bridge,
is also a quartz conglomerate, and the strata have a high easterly dip.
At one point it is probably continuous to the second road running par-
allel with the Connecticut, as it outcrops immediately east of the road
near J. D. Chase's. In some places the rock has the character of an in-
durated schist, and the pebbles can scarcely be recognized, but elsewhere
they are very distinct. In Charlestown the most northern point where
the rock was seen is Rattlesnake hill ; and on top of this hill the pebbles
are almost altogether quartz and quartzite. The largest are from four to
five inches in diameter ; but descending to the railroad the pebbles dis-
appear, and the rock has the character of many of the quartzites. The
rock has a high westerly dip. Thus, with rocks opposite, we have a dis-
tinct synclinal axis.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 413

The next outcrop southward is on the ridge extending northward from
Oak hill, where it contains pebbles, and encloses many large fragments of
the argillaceous staurolitc schist so extensively developed to the east in
Charlestown. South of the summit of Oak hill it turns eastward, and
crosses the road just north of the grist-mill. Here it turns to the south
again, and crosses the road running east from the grist-mill near H.
Hall's; thence extending south it forms the summit of the hill directly
east of the village of Charlestown, but at the south end of this hill it very
suddenly disappears. Towards the south part of the town, and on a ridge
south-east of school No. i, we have probably the same band of rocks.
The band comes to the road near A. Powers's, and it extends north-east
towards H. Hull's, Jr.; but the band of quartz schist that extends along
the road north of Hull's does not so clearly belong to this group of rocks.

The Eastern Band.

The ridge of Perry mountain is in part quartzite ; but there is a large
proportion of quartz, which is intrusive with other rocks. At the first
cemetery west of Unity Centre there is a band of quartzite which ex-
tends through the town. South it runs nearly parallel with the road, and
extends into Acworth; northward it crosses the road near P. Smith's,
and outcrops between J. Luf kin's and Mason Huntoon's, but probably
disappears beneath the mica schist before it reaches Newport. South of
Unity Centre and east of A. C. Sleeper's there is an outcrop of quartzite,
but it is very limited. On the road from Unity Centre to Gladden hill,
just east of the stream near school No. 3, there is another band of quart-
zite ; also directly south, at the forks of the two branches of Little Sugar
river, there is quite an extensive outcrop. An extension of this band
can be seen on the east of the road going south from this point towards
Acworth.

Acworth. In this town the last-mentioned band of quartzite crosses
the road going up the hill south of K. Smith's. Just south of William
Putnam's, on both sides of the road, quartzite is largely developed. Half
a mile south of Putnam's it is on the east side of the road only, and far-
ther south it has not been traced, unless the small outcrop that crosses
the road running north-east from Acworth Centre is a continuation. In
the west part of Acworth, extending along the border of the town, there

414 STRATIGRAPHICAL GEOLOGY.

are several areas of singular shape. In the north-west corner there is an
extension southward of Perry mountain. Near J. Grant's it crosses the
road, and on the south it terminates in an abrupt hill, the strike pointing
down a deep valley towards the south-west. The most remarkable area
is at Z. Slader's, where it is circular in form ; and the strike conforms
to the shape of the hill as though there had been a doubling up of the
whole mass. The surrounding argillaceous rock also shows great dis-
turbance.

On the road up Stebbins brook at the first there is an extensive out-
crop. It runs a little south of east, and appears on the road at T. Dun-
can's. Here it turns south, and can be traced for three fourths of a mile,
but it outcrops on Cold river in Langdon a quarter of a mile from the
line of Acworth.

Charlestozvn. In the eastern part of Charlestown we have Sam's hill,
which, on the west, is largely a quartz conglomerate. It is an immense
triangular area, sending an arm north-westerly, which crosses the road
at the height of land near William Rupp's ; another arm goes south-east,
extends into Langdon, and outcrops near E. Baldwin's. The west point
of Sam's hill is a distinct conglomerate; but the arms north-east and
south-east are generally like the quartzites elsewhere. But in its exten-
sion northward, after it crosses the road near William Rupp's, where it
disappears beneath the argillaceous schist, it shows pebbles on the weath-
ered surface.

Alstead, and southward. On the south-west extremity of Cobb's hill
there is a limited area of quartzite, in which the joints are not so marked
as elsewhere. In the west part of the town, a quarter of a mile south of
A. Alden's, there is another small area with well-marked joints. In Wal-
pole the quartzite can be seen in the central part of the town, on the
road from where the old church stood east to Fisher brook. On the road
that crosses Sugar brook, where it turns to the south, there is a quartz
conglomerate, and some of the pebbles are a foot in length. From the
general section, it will be seen that the quartzite is unconformable with
the mica schist, both on the east and west. In the south-east part of the
town, on a small stream a few rods north-west of Asa Gilbert's, we find
quite an extensive outcrop of quartzite; and this may be an outlier of
that which is so extensively developed in Westmoreland. Although there

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 415

are many outcrops of qiiartzite in Westmoreland, the most extensive is
south-east of Granger's mill and just east of a road now practically dis-
continued. The strata dip nearly north-west, generally about 15°; and,
what is rather uncommon, we have in it great veins of quartz. On the
south-east there is a narrow band of wrinkled argillaceous schist ; and on
the north-west a similar rock that extends to Westmoreland depot. This
wrinkled schist probably entirely surrounds the quartzite, and rests on its
edges. Just above Granger's mill, in the stream, we have the mica schist
with staurolite, that is the jDrevailing schist of Unity and Acworth. Here,
with strata nearly horizontal, it lies on the quartzite. The rock that out-
crops on the road near Westmoreland village seems rather to belong to
some of the lower formations, though it has in its jointing and cleavage
some resemblances to the Coos quartzite. On the road now discontin-
ued, that runs east from the Hill Village, we find quartzite dipping di-
rectly north. Near Wm. Starkey's the quartz schist probably belongs to
the quartzite band, and, with varying texture, extends south-west to the
town line. A rock that resembles it very closely is found at the molyb-
denite mine; but a typical variety of the quartzite is found south-west
of the mine near T. Dunham's, in the corner of Chesterfield. South-
east of Dunham's, near T. Briggs's, we have a band of whitish quartz
schist, which resembles that at Starkey's.

South-east of Factoryville in Chesterfield, perhaps a hundred rods from
the church, there is a marked outcrop of quartzite. While most of the
rock is like ordinary quartzite, where the rounded grains appear to be
imbedded in a purely siliceous, glossy-looking cement, there are masses
of the rock here in which the cementing material is almost altogether
wanting, and the rock is really a white, friable sandstone. A few dark-
shaded lines running through it give to the rock the appearance of lime-
stone ; and it was thought to be marble by the country people who had
seen it. At school No. 12, south of Spofford lake, a narrow band of
quartzite extends southward nearly a fourth of a mile. West of the lake,
on the hill north of William Bennett's, the quartzite appears, and proba-
bly extends southward, as it crosses the road half a mile west of the
Lake house ; and on the road from the lake to Chesterfield it can be seen
on the west of the road. In the south-west part of the town, near a saw-
mill, we have probably the extension northward of the quartzite so exten-

4l6 STRATIGRAPHICAL GEOLOGY.

sively developed on the mountains southward. South of the Brattleboro'
bridge the quartzite is just opposite E. S. Horton's, and on the side of
the mountain north it has been quarried; the stratification and jointed
structure of the rock enable the workmen to break it into fragments suit-
able for building-stones. It is quite probable that the strata are here in-
verted. A more extended notice of this quartzite, in its extension to the
south, will be found elsewhere.

The dip of the quartzite is as follows :

Charlestown. At T. Duncan's, S. 75° E. 58°.

At H. Hall's, S. 75° E. 35°. South-east of N. Hayward's, N. 60° W.
On Sam's hill, N. 40° W. 40°. 20°.

On hill east of Charlestown village, N. 80° At Wm. Putnam's, S. and S. 10° W. 28°.

E. 15°. At Z. Slader's, N. 22° and N. 50° E. 24°.

North of Hull's, Jr., N. 30° W. 18°. Near L. R. Hardy's, probably north.

On Rattlesnake hill, 38° W. 40° to 70° N. At T. & J. F. Murdough's, N. 20° W. 25°.
On Skitchawaug mountain, east side, N. Cheste7-field.

7o° E. 76°. North of Wm. Bennett's, S. 80° W. 30°.

Unity. . East of Factoryville, S. 10° E. 15°, and S.

At P. Smith, S. 50° E. 20°. 10° W. 62°.

West of H. Smith's, S. 80° E. 20°. West of Lake house, N. 80° W. 35°.

At cemetery west of Unity Centre, N. 80° On mountain north-west of H. Streeter's,

E. 25°. S. 70° E. 50°.

Near Mrs. McClure's, S. 30° E. 38°. Westmoreland.

Acivorth. At Westmoreland village, vertical.

At J. H. Howe's, S. 30° E. 12°. Near Mrs. Carlisle's, N. 40° W. 25°.

At K. Smith's, S. 50° E. 20°. At A. B. Cole's, vertical.

At J. Grant's, jjrobably horizontal. At J. Cowdrey's, N. 70° W. 20°.

Quartzite on the Border of the Gneissic Rock of the Merri-
mack Valley District.

The band of quartzite that is so persistent along the eastern border of
the Coos rocks of the Connecticut valley, and is sometimes found in
irregular, detached areas associated with the gneiss, has its most north-
ern outcrop in Landaff. It is usually a compact, fine-grained, and dis-
tinctly granular rock, very hard, often brittle, and is frequently, especially
to the southward, divided by numerous joints, which cause it to split into
fragments more or less rhomboidal. The typical varieties, when exam-
ined by a lens, seem to be made of grains of quartz imbedded in a sili-
ceous cement ; but they are found to pass, on the one hand, through a

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 417

qiiartzose mica schist into a genuine mica schist, and, on the other, into
quartz conglomerate. When the mica becomes quite apparent in the
rock, we shall designate it as quartz schist, otherwise, quartzite, or, where
pebbles are present, quartz conglomerate. Here, as in many places else-
where, it consists of a narrow, interrupted band. It is first seen near the
forks of the road at O. Bronson's, and south at W. Hunt's. It is uncon-
formable with the gneiss on the south-east, and with schist on the north-
west. It is found in the south-west part of the town, on the road, now
practically discontinued, that runs south from Landaff village. The road
passes over it on the hill south of J. Clough's. We have gneiss here on
both sides of the quartzite, though unconformable, but both dip westerly.
The strike of the rock would take it near the outcrop at Bronson's. To
the south it keeps on the east of the road, but crosses it about half a mile
north of D. N. Page's, and an eighth of a mile west of Page's it crosses
the road running parallel with the river. Here the strike is somewhat
variable ; it has a fine-grained gneiss on the east, and a coarser variety
on the west. A characteristic of this band is the low dip of the strata.
It rarely exceeds twenty degrees. West, near Mrs. Grant's, there are
isolated bands of quartzite that dip north.

In the east part of Benton there is one of the most extensive outcrops
of quartzite that we have; and we find here all the varieties, — quartz
schist, quartzite, and quartz conglomerate. It first appears south of D.
Howe's, and it may be a continuation southward of the band that out-
crops on the north side of the Wild Ammonoosuc in Landaff. In shape,
this area, as a whole, in Benton and its extension into Haverhill, is pecu-
liar to this rock. The strata seem to have been doubled up and bent on
themselves ; and where the great fold occurs it forms the ridge and sum-
mit of Black mountain. From Howe's the strike is southward ; on the
ridge more to the west, and on the summit of Black mountain, and on the
ridge west where it has its greatest thickness, it is almost directly east
and west. It differs from the area north in the greater inclination of the
strata.

Near D. Howe's, east of the quartzite, we have a hornblende gneiss,
with nodules of epidote ; and east of this is the common gneiss. On the
west of the quartzite we have gneiss, the strata of which are nearly ver-
tical ; and the inclination of the strata of the gneiss on the east is greater
VOL. II. 53

41 8 STRATIGRAPHICAL GEOLOGY.

than that of the qiiartzite, though all the rocks may have a westerly clip.
The quartzite extends southward along the ridge of Sugar Loaf mountain,
and is followed both on the south and west by protogene gneiss. Near
the summit of Black mountain, and on its southern slope, is a greenish
chloritic and micaceous schist. At an old mill between Black mountain
and Sugar Loaf is a conglomerate composed chiefly of quartz, quartzite,
and pebbles of a whitish indurated schist. Where the quartzite outcrops
in Haverhill, on the road north of Mrs. S. Tenney's, it is associated with
hornblende schist, as is also the mica schist on the south side of Black
mountain. On both sides of the quartzite in Haverhill we have proto-
gene gneiss ; and it suddenly terminates here, unless it forms a transition
state into the arenaceous whetstone slate near E. Dean's.

In Piermont, quartzite is found in the east part of the town ; and in
the north part, where it is crossed by the section, we find gneiss ; on the
east and on the west, wrinkled mica schist, that carries staurolite, horn-
blende and mica schists. Farther south, on Piermont mountain, there
is protogene gneiss on both sides of the quartzite ; and there seems to
be the same doubling of the strata that we find in Benton. As it extends
south and passes into Orford, a short distance east of where the road
crosses the town line, south-west of the mountain, the rock is a quartz
schist. Near the house of P. C. Savage, in Orford, it is a quartzose mica
schist ; and it seems to be the case, nearly everywhere that this band
thins out, that it forms a transition state into mica schist. In the north-
east corner of Dorchester, between McCutchins pond and the summit of
Smart's mountain, a band of quartzite has been traced. Whether it is
connected with that to the west of E. Lamprey's we have not been able
to determine, though, from the many isolated bands elsewhere, it is not
improbable that this may be. The rock on both the east and west sides
of the summit of Smart's mountain is a friable, tender gneiss ; and it has
the protogene gneiss on the west and the Lake gneiss on the east. The
unconformability of this band of friable gneiss with the other gneiss will
be shown when we come to speak of the common gneiss.

The quartzites, quartz schists, and quartz conglomerates of Gilsum,
Surry, and Keene are among the most interesting of any we have exam-
ined, but they require a much more careful study than we have been able
to give them, to understand fully their relations to the other rocks. Then

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 419

there is the quartz of Mine ledge, that extends south into Westmoreland
and Keene, and though with the protogene gneiss it sometimes forms a
breccia, yet it is entirely unlike the quartzites and quartz conglomerates.
The quartzites here do not differ essentially from those in the topograph-
ical district of the Connecticut valley. Graphite, however, has been found
here, though nowhere else in the quartzites ; and the associated rocks are
quite different from those found elsewhere. Among the questions that
arise, is the relative age of the quartzite and quartz schist, as compared
with that of the quartz conglomerate. There are many reasons for sup-
posing that the latter are the most recent of all the rocks in this section
of the state. The most easterly band of these quartzose rocks has its
northern outcrop a quarter of a mile north-east of the Fish place in Gilsum.
The strata here have been much disturbed, though the general strike is
east and west, and the dip south. About half a mile south the dip is S. 22°
E. 20°. Not far from M. T. Wilcox's, the strata seem to have been little
disturbed. The outcrops extend half a mile nearly parallel with the road ;
and the strike is almost directly north and south, while there is a slight
westerly dip. Alongside of a small stream there is a fine opportunity for
examining the strata, which here contain flattened pebbles. This rock
is cut off on the north by a coarse intrusive granite. We have not been
able to trace it south, as the valley across which the strike would carry
it is covered by drift. But in Keene, on the west side of Beech hill, we
find a quartz schist, also on the hill a little east of south from the station
at South Keene. On Surry mountain the general strike of the Montal-
ban gneisses is nearly north and south ; but on the south end of the
mountain, about half a mile north of the Austin place, we find a band of
quartz conglomerate apparently resting on the contorted strata of the
gneisses. It extends north-east, and is found on the hill just back of J.
B. Elliott's in Gilsum, and also just west of O. McCoy's, about twenty
rods from the road. The pebbles are from an inch to more than a foot
in diameter, and are generally oblong. This band, running diagonally
across the general strike of the rocks of the country, is shown clearly
to be the most recent of all the rocks in this section. In the south-
west part of Surry, a few rods east of H. Britton's, there is a limited out-
crop of quartzite, and it is very near the quartz. In Keene, south of the
railroad and on the range of hills known as West mountain, there are

420 STRATIGRAPHICAL GEOLOGY.

apparently two bands of quartzite, though they may be connected at the
north end of the mountain. Ascending the mountain from the east, we
do not find the hornblende schist that usually succeeds the protogene
gneiss ; but the quartzite rests on the gneiss, and has a westerly dip of
from 15° to 20°. It contains what seems to be flattened pebbles. Rest-
ing on the quartzite we find a folded and contorted mica schist, which
sometimes carries andalusite. The quartzite bends around as we go tow-
ards the north end of the mountain. It has a southerly dip, and is prob-
ably connected with the second band of quartzite that we find when we
go directly west across the mountain. This second band has a slight
dip to the east, thus giving to the quartzite a synclinal structure. The
quartzite rests on the protogene gneiss ; and the contorted mica schist
is included in the quartzite. The two bands of quartzite near the south
line of Keene are perhaps a mile apart. The westerly band of quartzite
contains graphite, and there is quite a large opening where it was for-
merly worked. The mica schist near the graphite contains some very
pure quartz veins. On the north-east side of the mountain, west of
White's, the quartz found in the gneiss was at one time used in the
manufacture of glass.

Dip of the Quartzite, Quartz Schist, and Quartz Conglomerate.

Landaff. Piermont.

40 rods south-west of O. Brownson's, S. 2° At south end of Piermont mountain, N.

E. 20°. 22° W. 40°.

h mile south of J. Clough's, N. 68° W. 15°. Dorchester.

North of D. N. Page's, N. 50° W. 15°, Between McCutchins's and top of Smart's
k mile west of Page's, N. 70° W. 20°. mountain, N. 82° E. 50°.,

Near Mrs. Grant's, N. 10° E. 40°. Enfield.

Benton. At Lily pond, N. 80° E. 60°.

At D. Howe's, N. 72° W. 40°. At D. L. Smith's, S. 65° E. 48°.
On ridge south of D. Howe's, about half Granthatn.

way up, N. 68° W. 50°. South-west of Sugar Loaf hill, S. 45° E.
At top of ridge, N. 48° W. 65°. 80°.

On summit of Black mountain, N. 5° W. At L. M. Bean's, N. 34° W. 85°.

70°. Opposite Mrs. Chase's, vertical.
At saw-mill north, N. 15° W. 40°. Plainfield.

At west end of Sugar Loaf mountain, N. At W. L. Martin's, S. 64° E. 52°.

10° E. 50°.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 42 1

AFeivport. General strike on top of ledges, N. 11°

East side of Blueberry ledge, S. 82° E. 50.° W. ; dip easterly.

The dips of the quartzitcs of Unity and Acworth have been given on
page 416.

Cilsiun. Surry.

Near the Fish place, S. 38° E. 20°, and North of the Austin place, S. 53° E. 40°.

variable. Keeiie.

At M. F. Wilcox's, N. 82° E. 15°. On West mountain, S. 36° E. 50°.

Argillaceous axd xVrgillaceous Mica Schists.

There are very few purely argillaceous schists in this area, and those
that arc found are exceeding variable in texture. In Charlestown the
rock is thick-bedded, and is very little broken by joints and cleavage
places. In many places it contains staurolite in tessellated crystals like
chiastolite. In Westmoreland the rock is decidedly micaceous, and then
further south along the Connecticut, opposite Brattleboro', it differs very
little from ordinary clay slate.

From North Charlestown the argillaceous schist extends east to the
top of Fifield hill in Unity; thence it extends southward through the
central part of Charlestown into Langdon, until it is cut off or crowded
out by the gneiss. Along the eastern border of this area the strata are
frequently nearly vertical and sometimes contorted, as at Wm. Smith's,
Both on the east and west, in the vicinity of the quartz conglomerate,
the strata are often bent, and generally stand at a high angle. At the
height of land on the road from Charlestown to Langdon, the strata are
at right angles to the quartzite. But as on the road near Ashbel Ham-
lin's, where there is neither quartzite nor quartz conglomerate near, the
strata are nearly horizontal. On the southern border of the CharlestoAvn
area, at L. Fairbanks's, we find the strata again almost vertical. With
the quartzite in the west of Acworth, there is a band of argillaceous mica
schist that has very much the same relation to quartzite as this in Charles-
town, It extends from Z. Slader's south, and is found with the quartzite
at T, Duncan's, where the strata are vertical. We have here a repeti-
tion of the schist and quartzite of Charlestown,

The area of argillaceous schist in Walpole is quite limited, and lies
between Drew mountain and Walpole village. There is, however, an

422 STRATIGRAPHICAL GEOLOGY.

argillaceous mica schist that outcrops in the southern part of the town,
west of the Christian church, and extends into Westmoreland. There is
also an outcrop below the railroad station, and also at school-house No, 9.
Southward in Westminster, along the river at H. P. Farr's, there is an
argillaceous mica schist, containing staurolite that undoubtedly belongs
with these Coos schists.

The principal rock of the Mount Gilboa area in Westmoreland is an
argillaceous mica schist, but the hill south-east of the railroad station is
eruptive granite. Immediately north of this the dip of the rock is exceed-
ingly variable, and continues so until we reach the top of the ridge ; the
rock here is ferruginous, and dips N. 23° to 30°. Following the ridge,
which runs north-east, the rock is quite free from iron, and carries stau-
rolite in abundance, and there is very little change in dip. Following
the railroad south from the station, after passing the granite, we find in
the first cut an excellent place to study the argillaceous schist. At the
north end, on the east side, the strata appear to be vertical, but suddenly
they become horizontal, and they continue so, with occasional folds and
bendings, to the end of the cut. The rock becomes more micaceous to
the south, and at the Hill Village it is an argillaceous mica schist. East
of the church it is quite ferruginous ; it contains a quartz vein and a nar-
row band of eruptive granite. To the south-east, at Daniel Farr's, there
is another narrow band of eruptive granite; and this is succeeded by
hornblende schist.

On the road south from school-house No. 9, the rock is a dark mica
schist. It is very much wrinkled, and has the general appearance of the
argillaceous schists. South, near the town line and close to S. Amidon's,
it is unconformable with a quartzite band that is on the west. In Ches-
terfield the distinction between these rocks and the mica schists is not
so marked as in the towns north, but still it is very noticeable even here.
The argillaceous mica schist occupies the central part of the town, to the
west and south-west of Spofford lake. It outcrops at Capt. C. N. Clark's,
C. F. Daniels's, and at many other places. We have given in Fig. 66 a
section that shows the argillaceous mica schist in a new relation, from
which it appears there has been an inversion of the rocks on the west,
bringing up in the axis the quartz schist, and causing the western band
of quartzite to rest on the schist. Southward, at the forks of the road

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 423

near John Harris's and at J. B. Fisk's, there are prominent outcrops. It
is the principal rock nearly as far south as A. G. Newton's in Hinsdale,
where it is cut off by granite. The argillaceous schist opposite Brattle-
boro' seems to be rather an outlier of the great band that extends from
Vernon northward along the Connecticut. The boundary between this
rock and the slate that is sufficiently fissile for roofing, and the boundary
between it and the Calciferous mica schist, cannot be readily traced; but
perhaps closer study would enable one to do it. The strata of this band
are very often nearly vertical. Opposite Brattleboro' the dip is E. from
75° to 80°, but the inclination, as we go east, is less. Going up the river,
we find both easterly and westerly dips. In Chesterfield this rock does
not extend along the river above Catsbane brook, for here we have a hard
siliceous schist that may belong to some older group. This is suggested
by the fact that we have at G. T. Dunham's a hornblende schist, which
must extend some distance up the river, as it appears above Putney vil-
lage. The argillaceous schist does not extend more than a mile and
three fourths below the Brattleboro' bridge, and here it is succeeded by
quartzite. The argillaceous schist in Fig. 6^, across Wantastiquit moun-
tain, shows the nearly vertical strata that characterize this rock here
and its extension west in Vermont. The exception, as we go east from
the crest of the first valley, is probably due to the folds so common in
the argillaceous schist northward. On the east it is often vertical, but
sometimes it has an easterly and sometimes a westerly dip. In the south
part of Winchester, near C. Lyman's, we have a band of argillaceous mica
schist, of limited extent, and a quartzite band on the west.

It is difficult to determine with certainty the relation of these argillites
to the quartzite, since the strata seem so often to be inverted ; but if the
argillite of Charlestown is identical with those southward along the river,
then it must be more recent than the quartzites, since the immense frag-
ments found in the quartzite must have been folded in from overlying
strata. The following dips have been observed :

Charlestown. Near forks of road east of Miss Wheeler's,
At William Smith's, strata nearly vertical N. 55° W.— variable.

and contorted. \ mile north-west of J. Gregg's, S. 30° E.
At G. Hamlin's, N. 55° W. 50°. 40°. ; \ mile north-west of J. Gregg's,

South-west side same hill, N. 35° E. 55°. S. 70° E. 50°.

424

STRATIGRAPHICAL GEOLOGY.

Near L. Fairbanks's, S. io° E. 80°.
Near J. Gregg's, S. 50°.

La/igdoa.
At J. Bairs, S. 80° E. 50°.
Near E. Baldwin's, N. 62° W. 3°.

Acwortk.
50 rods west of T. Duncan's, S. 80° E.

53°.
i mile south of Z. Slader's, N. 40° W. 64°

and variable.

IValpolc.
At J. W. Hayward's, N. 50° E. 20°.
At S. W. Griffin's, N. 20° W. 25°.
Near Griffin's, north, E. 58°.
Near forks of road noith of Griffin's, N.

80° E. 24°.
60 rods south-west of A. P. Nichols's the

strike is N. 68° W. — dip variable.

The rock has a tendency to split in-
to longitudinal fragments.
South of Sugar brook, near E. A. Marsh's,

N. 8° W. 8°.
South of Westmoreland station, strata very

much contorted.

Mica

h mile north-east of the station, N. 1 1° W.
20°.

i mile east of Mrs. James Ware's, strata
wrinkled, but dip westerly.
Chesterfield.

At C. F. Daniels's, 5. 50° E. 30°.

At C. N. Clark's, S. 50° W. 13°.

At Chesterfield village, S. 60° W. 10°.

At S. Waldo's, S. 30° E. 10°.

Near J. C. Hubbard's, strike N. 10° W. ;
dip both east and west.

Near J. Cobleigh's, S. 45° E. 55°.

At J. B. Rich's, much contorted, and some-
times bent at right angles to the gen-
eral strike.

At Brattleboro' bridge, N. 70° W. 75°.

On Wantastiquit mountain, N. 40° E. 20°.
Hinsdale.

On Bear hill, south side, vertical, or near-
ly so, dipping easterly.
Winchester.

Near C. Lyman's, N. 40° W. 42°.

Sen

The mica schist of this area is characterized by having its strata, as a
whole, more nearly horizontal than any of the other rocks. It is often
swollen into gentle anticlinal curves, and has corresponding synclinal
depressions ; but sometimes, where it comes in contact with other rocks,
the strata are highly inclined. It rests unconformably, both on the
quartzite and the gneiss, at least on the protogene gneiss. In a following
chapter on the gneissic area of the Merrimack topographical district,
there are several sections across the gneiss, the quartzite, and the schist.
The mica schist has generally a thin, laminated structure ; it often con-
tains staurolite crystals ; cyanite is sometimes found in it, but graphite
seems to be limited to the rocks of the preceding groups. Mica schist is
more extensively developed in the southern part of the Connecticut valley
topographical district than either of the other kind of rocks. It forms a
narrow band in the central part of Newport ; but where it enters Unity

— Sections in the Connecticut Valley.—

By J. H.Huntington.

^ i ^

Fie. 6^. From the Devices Gully^ Charlbstown , to the Height
OF Land o/w the Lan g don Road.

=?

B

f

^°cr

Modified Drift.

i / 1 1«

r€#^

^fPP^y

Fig. 65. From Rockingham^ Vt. , t-o Kilburn Peak.

Fig. 66. From Dan/el Bornham's^V^estmoreland, to C^pt. C.N. Clarks, Chesterfield.

Fig. 67. /\c«oss Y^antasti^uit Mt. to Road oveh Beak Hill.

yERTicAL Scale. , 150O Feet to am Inch.

HoRaoNTAL >' ,1 Mile » >• » """"

V\t^\<2i"^-<?t

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 425

it embraces a section of country several miles in width west of the gneiss.
It is developed in its characteristic form in Acworth, and there is a small
but important area north and east of Sam's hill in Charlestown. Just
north of the Langdon road, at the height of land north of Sam's hill, we
see plainly the super-position of the mica schist. In Fig. 64 the relation
of the rocks in Charlestown is shown. One thing to be noticed is that
the argillaceous schist, where it comes in contact with quartzite, is at
right angles to it, and, on account of the argillaceous schist, the quartz
conglomerate, and the mica schist dipping in different directions, it does
not show the exact relations of these rocks. The strata of argillaceous
schist are very much contorted, but the unconformability with the quartz
conglomerate is apparent, while the latter runs under the mica schist.
The western band of quartzite shown on this section is farther north
on Oak hill, vertical, so that probably its normal position, in relation to
argillaceous schist and the Calciferous mica schist, is an anticlinal. The
common gneiss is on the eastern border of the mica schist, both in
Unity and Acworth. In the south-east part of Langdon, and also in
the adjoining town of Alstead, there is a mica schist that may be a
continuation of that in Charlestown and Acworth. In Langdon it out-
crops at the forks of the road, near G. Kingsbury's on Walker's hill, and
many other places. At the first locality mentioned it contains andalusite.
In Alstead, it is found on the south-west side of Cobb's hill, where it
contains cyanite, which, near the surface, has undergone decomposition,
so that it has the appearance of mica.

Going towards the south-east, this mica schist appears in Walpole ;
there are extensive outcrops on the Walpole and Surry road, especially
near the height of land, and it is like that of Unity and Acworth, and
very frequently it contains staurolite. South-east, in Surry, the strata
are nearly horizontal, and, as in the vicinity of school-house No. 4, they
rest on the protogene gneiss. The schist in the north-west part of Surry
and in the south-east corner of Alstead seems to be rather the argilla-
ceous mica schist than the common mica schist.

In Westmoreland the principal area, and this limited, is found in the

south-east part of the town. Here the strata are nearly horizontal ; and

the rock occupies the top of the hill above L. Hyland's. In a following

chapter on the gneissic area of this town, there is a section showing the

VOL. II. 54

426 STRATIGRAPIIICAL GEOLOGY,

relation of mica schist to the underlying rocks. East of the Hill Village,
and near Fall brook, there is a very narrow band of mica schist between
the argillaceous mica schist and the eruptive granite, but it has not been
followed either north or south. We have on West mountain, in Keene,
very much the same succession of rock as in the east part of Westmore-
land. A section (Fig. 80) will be found in the following chapter.

In Chesterfield the mica schist occupies a very irregular area. This is
particularly true of its eastern extension. Just west of Factoryville we
have a slaty gneiss that dips at a small angle to the south. At the vil-
lage, in the stream at the Turning shop, there is a quartz breccia, and
directly east there is quartzite ; then south of this, and on the road run-
ning east, we have the mica schist, and its greatest width north and south
is not more than two miles. The eastern limit of the principal area is
not far from school-house No. 14. There is, however, a narrow band of
schist east of the band of protogene gneiss at the forks of the road east
of school-house No. 14. South of W, Bingham's the mica schist has a
laminated structure, and is very much contorted, but the general dip is
southerly. This area is the limit southward of this band of mica schist.
The following are some of the dips that have been noted :

Unity. At G. Gilmore's, N. 40° E. 20°,

At forks of road west of P. Smith's, N. 80° At A. J. Straw's, variable and contorted.

E. 30°. Near A. H. Church's, N. 80° E. 14°.

At J. Sleeper's, N. 80° E. 15°. I mile north of T. & J. T. Murdough's, N,
At A. C. Sleeper's, S. 60° E. 12°, and S. 10° W. 8°.

30° E. 20°. South-east of N. Haywood's, N. 20° W,
At O. Sleeper's, S. 68° E. 20°, 13°.

At Col. E. J. Glidden's, E. 8°. Walpole.

At G. Breed's, S. 30° E. 15°. At R. Leonard's, strata nearly horizontal.

Acworth. Chesterfield.

At Acworth Centre, S. 30° W. 22°. East of Factoryville, S. 10° E. 13°.

Calciferous Mica Schist,

There are three limited areas of the Calciferous mica schist. The
most northern is in Charlestown, west of the quartzite. It extends from
the Cheshire bridge southward along the Connecticut river. It consists
chiefly of argillaceous bands, which have an uneven cleavage, and the
rock breaks up into irregular fragments, on account of the swelling of

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 427

the concretionary veins of quartz between the lamina; of the schist. On
the general section, there is a change in the dip of the strata. If this
exists in reality, the band next to the river is probably slate and not Cal-
ciferous mica schist. This would not be improbable, since the rocks on
the opposite side of the river are Huronian. The Calciferous mica schist,
both in Rockingham, Vt, and on the Connecticut below South Charles-
town, presents a monoclinal structure ; and we have a narrow band of Huro-
nian rock between, while in their present inverted position the Montalban
rocks rest upon the Calciferous ; and these relations are shown in Fig. 65.
In Alstead, east of the gneiss at Paper Mill Village, there is a band of
Calciferous mica schist. It extends up Warren brook above the road to
Alstead Centre, and up Cold river into the edge of Langdon. The rock
consists of a decomposing mica schist and a bluish siliceous limestone;
and everywhere the rock appears the strata are nearly horizontal.

The third area is in the extreme western part of Westmoreland. At a
spring by the side of the road, near Daniel Burnham's, there is a siliceous
limestone interstratified with argillaceous schist. The strata are nearly
vertical, but have an easterly dip opposite the quartzite and schist in the
north-west corner of Chesterfield. At A. B. Cole's we have slate with-
out the limestone. This band as a whole resembles very much the rocks
along the river in Brattleboro' and those immediately opposite in Dum-
merston. The following dips were observed:

At grist-mill west of H. Hall's, S. 85° E. East of grist-mill, Alstead, nearly horizon-

50°. tal.

At South Charlestown, S. 75° E. 60°. At Farmer's foundry, W. 10°.

At railroad a mile north of South Charles- At D. Burnham's, Westmoreland, N. 50°

town, N. 70° W. 65°. E. 70°.

Eruptive Rocks.

The absence of eruptive rocks in this area is quite noticeable, as there
are very few compared with those found in other parts of the state. The
boulders of trap that occur may have come a long distance, since the boul-
der of serpentine seen in Keene must have come from Vermont, and some
of them have travelled twenty-five or thirty miles. The only eruptive rock
of any extent that is found is in Westmoreland, and forms most of the hill
south-east of the railroad station in the west part of the town. The railroad

428 STRATIGRAPHICAL GEOLOGY.

cuts the granite near the station, but it extends only a short distance on
either side. It extends to the top of the hill ; but on the north side, a
few rods from the summit, the schist comes in contact with it. The
granite east to the base of the hill and a narrow band are crossed by the
railroad nearly opposite school-house No. 12.

HELDERBERG SECTION OF THE CONNECTICUT VALLEY.

For the sake of properly setting forth the relations of the interesting
series of Helderberg rocks at Bernardston, Mass., to the older New
Hampshire schists more or less associated with them, I propose to de-
scribe the formations between Chesterfield or Brattleboro', Vt., and the
fossiliferous group in Bernardston in a special section, having reference
to the question how far the rocks connected with the crinoidal limestone
are of the same age with it. The towns concerned are Hinsdale, Ches-
terfield, and Winchester, N. H., Brattleboro', Vernon, and Guilford, Vt,
and Northfield and Bernardston, Mass. The area comprises about ninety
square miles. Being at the boundary of the states of New Hampshire,
Vermont, and Massachusetts, the several geologists have mostly confined
their explorations to their respective territories, and I regret not to have
been able to study the towns outside of New Hampshire as thoroughly
as is desirable. The formations represented in this area upon a special
map, with contours, Plate XVHI, are the following: i. Bethlehem gneiss.
2. Hornblende rocks. 3. Cambrian slates with siliceous beds. 4. Quartz-
ite. 5. Coos slates and schists. 6. The Helderberg limestone and its
accompaniments. 7. Trias. 8. Alluvium. The sixth of these groups
has been known for nearly fifty years ; and we have on record the views
of E. Hitchcock, Sir Charles Lyell, James Hall, J. D. Dana, J. P. Lesley,
and others respecting it. The other formations have been examined very
slightly, principally those in Vernon and Guilford, and are described in
the report of the geological survey of Vermont, 1861.

I. Bethlehem Gneiss.

The gneiss of Vernon and Hinsdale presents such a likeness to the
Bethlehem group in New Hampshire, that I refer it to that series without
hesitation. Connecticut river flows transversely across this area in Ver-
non and Hinsdale. The level of the surface outcrops is invariably quite

Pji^ate JCVIII.

Tr.^TE J^IX.

— Sections Illustrating the Helderberg Area,

Clay§ Slate.

U, Beds.

-«ifr""^,.T!V!,''

Ill

f/6. 68. A T Brattlcboro' Railroad Station ,
CurF, 2() Feet hish; S£Ctio/\,75 Fee t long.

FiG.b'S. Aloa'G Broad Brook in GuiLFORr- Am Vernon.

___ VfSr/CAL Sc.f^Lt. 200C FeST TO AM I.VCH ^^

//o/n^'i.-^TAL .. , ^ Mile. >' « » .

5 ^ I

Clay Slate.

Bethlehem
Gneiss.

Mica Sc^

F/G.70 Through Central Vernon and H i n s d /kl e

\/e.P~TicAL Scale, SOOO Feet to \n Inch.

\lti^TicAL Scale, 3000 Feet

H0R,i0.yT»L ■■ , I;f^ A1,L£S

Fig. 71. Along State Line, from near Fall River to Winchester.

_____ \/£rtical scale, 3000 fc£t to ah inch.

HoH/TiONTAL >i .7,^ Miles <• •■ /- .

Fig.72. From S.W. Base of Bald Mt. to Grass Hill, in S.E.Cchner of Bernardston.

^^ Vertical Scale, SOOO Feft to ai^ Inch.

FtG.l^. On Williams^ Hill, BEfiNARDSTof^;
DterANCE, ^Mile; Vertical Scal£,Sooo Ft.to ANi/^cn.

Fig 74-. From Williams' H/ll to North Paut of Gill.

VEflTICAL SoALt,3000 FiET TOA-V Inc»

~~" HoHtzoHTAL. « ,iyi Miles • - " ■

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 429

low, being rarely elevated very much above the alluvial deposits. Upon
the general map the latter occupy a large part of the space properly be-
longing to the gneiss. Ledges may crop out beneath a sand bank just
enough to indicate the nature of the solid foundation, but not sufficiently
to be colored upon a map of so small a scale as two and one half miles to
the inch. Our special enlarged map will not be encumbered unnecessa-
rily by the surface deposits. The basin-shaped appearance of the Hel-
derberg section has been already alluded to in our chapter on Topogra-
phy, while the recently prepared contour lines exhibit the details. There
is more correspondence than is common in New Hampshire, in this sec-
tion, between the topography and the stratigraphy.

Represented upon the map, upon the east side, is part of an oval area
of porphyritic gneiss, ten miles long, lying in Chesterfield and Winches-
ter chiefly. It will be specially described in the next chapter. It is
regarded as older than, and hence underlying, the Hinsdale gneiss. In
Northfield, boulders of this rock are extremely common, enough to sug-
gest that it may be found in place there beneath the alluvium. If so, the
length of the oval area would probably be doubled, and thus extend much
farther south than the Bethlehem group, which barely reaches into
Massachusetts. These two older series do not join each other visibly,
because their boundary is covered by extensive developments of mica
schists and quartzite.

The structure of this gneiss is like that of the Hanover area, mostly
inverted, but the general inclination is reversed from that, being easterly
rather than westerly. The following are observed positions :

Verno7i. West of E. P. Brown's, 70° E.

Near L. F. «Sc G. F. Gould's, school district At west edge of formation, near school-
No. 4, 45° S. 20° E. house No. 7, 70° E.

Farther west, 55° southerly. Hinsdale.

At school-house No. 5, 40° E. On Elmore's island, easterly, the same as

West of railroad, between the church and at Cooper's point.

the Whithed family cemetery, sever- At school-house No. 4, east.

al ledges, 65° E. South of E. Ashcraft's, about N. 70° E.

Between the church and Vernon station on East of D. Fisher's, vertical ; strike about
railroad, 55° E. north and south.

This region was averaged by E. Hitchcock At S. E. Butler's, east.

at about 30° E. Between F. Thomas's and Bear hill, east.

430 STRATIGRM'IIICAL GKOLOGY,

At saw-mill near S. Tlionias's, northerly. South-east from village, N. 44° W. and

Winchester. 50° !•:.

At west edge o{ formation, 50° iN. 30° W. ; Warwick.

25° N. 40° W. ; 20° N. 40° \V. At west edge of the town, 20° N. 12° W.

Northficld.
At the west edge, do'^ northerly.

Tlic gneiss of the kisl thi-co towns Ijclon^^s to a range not mentioned
above, bordering- the Ilelderberg field on the cast. It is very likely of
the same age with the typical area in Hinsdale and Vernon. The dips
indicate a synclinal between the Vernon and Winchester areas, thus con-
firming the suggestion of their identity. I have not included certain
gneisses in Vernon and Northficld associated intimately with the quartz-
ite, believing them to belong to the latter series of rocks. They differ in
the absence of the talcose mineral and in being fine-grained, scarcely dis-
tinguishable from the quartzite.

The principal variation from the east dip is in the first two observa-
tions. Here, there is abed of crystalline limestone in the gneiss quite
near the border of the area, and, as usual, overlaid by hornblendic rock.
The southerly dip of these strata beneath quartzite and mica schist agrees
with our theory of the inversion and greater antiquity of the gneiss. The
limestone presents a slight likeness to the ]5crnardston rock; but a care-
ful examination did not reveal the existence of any fossils. The Bethle-
hem group in Orford and Lyme carries a very large bed of limestone,
which may be the analogue of this. Likewise, any bands of quartzite not
readily separated from the gneiss might be regarded as the equivalents
of the quartz seen at Hanover in it.

The general aspect of this gneiss may be expressed by the word gran-
itic, because the stratified lines are obscure. Plence it is possible that the
formation may be represented in the Whately and Hatfield area of sien-
ite, as given in the Massachusetts map.

HoiiNiu.KNDK Schist.

Our studies indicate the existence of a narrow band of hornblende
schist adjacent to several of the areas of Bethlehem gneiss in the Con-
necticut valley. Allusion has been made to the positions of several of
them, upon page 367, and others will be described in the following

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 43 1

chapter. The licklcrbcrg area contains an unusual amount of this rock,
and it seems proper to refer the c^rcater part of it to the same horizon
witli the hornblende bands of Slielburne r\'i]ls, Mass., l^rattleboro', and
the long belt from Marlboro' to Reading, Vt., Westmoreland, Plainfield,
Hanover, Orford, Canaan, etc., N. H. Often the rock is properly a horn-
blendic gneiss, and for that reason has not been distinguished from tlie
gneiss adjoining. In New Hampshire it seems to encircle areas of the
Bethlehem group. This suggests whether we ought not to incorporate
with these protogenic rocks other gneisses similarly enclosed, but devoid
of talc or chlorite. Objection has very properly been niade to separating
formations by means of mineral characters ; but we have now the means
of uniting common and talcose gneisses in this Bethlehem series, which
may be characterized mineralogically by the presence of the talc in a
portion of the group. The classification is based upon stratigraphy, not
lithology exclusively. We may be able to say that the gneiss of Shel-
burne Falls, the range between Marlboro' and Ilartland, Vt., as well as
the small Bratlleboro' area, should all be ranked as part of the Bethlehem
series, and hence probably corresponding with the Laurentian in age.

The hornblende rocks occur on both sides of the Hinsdale area. On
the west we have an excellent outcrop opposite the mouth of 15road brook,
dipping 50" east. It is about two hundred and fifty feet thick, of a glossy
black color, often containing epidotic nodules (Nos. 47, 48, of the cata-
logue). On the north edge of the gneiss we find it at H. Streeter's (Nos.
50, 52), and above the Thomas saw-mill (No. 47). On tlie eastern border
it appears east of S. E. Butler's (No. 51), at Davenport's island, and fifty
rods cast of F. Doolittle's (No. 46). These arc all in Ilin.sdale. After
crossing into Vernon I have noticed the same material, outside of the
gneiss, near the Whithed cemetery.

After reaching the line between Vernon and Northfield, an abundance
of hornblende rock, with a fine-grained gneiss, makes its appearance,
both of which seem to belong to a formation above the Vernon or Beth-
lehem gneiss, as just described. Both occur abundantly farther south.
On the town line the dips are all easterly, hence indicating inversions.
The details will be described presently (Fig. 70). On a line diverging from
this section, at the crossing of the state line by a road from Lily pond
south-easterly, and thence following the track as far as the rocks extend.

432 STRATIGRAPHICAL GEOLOGY.

the position of the strata is essentially the same, while the hornblende has
diminished in amount, occurring in two places. This rock occurs about a
mile south of the Vernon line, along Bennet's brook, dipping south-east-
erly. My father's map of Massachusetts represents this hornblende band
as extending along the east line of Bernardston southerly, reaching to the
Connecticut river at the ferry leading to Northfield village, thence occu-
pying the whole area from the Connecticut west to Woodard's or Una-
dilla brook. My own observations confirm and extend this area, at the
expense of the red sandstone. Less than a mile from the Turner's Falls
ferry, in Gill, the hornblende rock shows itself; and I did not see any-
thing else as far as to the ferry crossing to Northfield, where are also
some related metamorphic strata. I also find this rock over a mile to
the south-west from Grass hill, dipping somewhat south of east. Be-
tween this point (four corners in the road) and Otter pond, in the north-
west corner of Gill, are extensive quartz ledges, with north-westerly dip.
We may therefore extend the hornblende more south-westerly than be-
fore, and perceive its want of conformity to the quartzite, on account of
the change in the dip. The north part of Gill is covered with the irreg-
ular lenticular hills of drift, to be described hereafter. Without doubt
their abundance has led previous observers to overlook the presence of
the older schists, and to believe the place occupied by the Trias. Our
sketch shows that the hornblende pursues a more north-easterly course
than is indicated upon the Massachusetts geological map.

3. Cambrian Slates.

Clay slates occupy the western part of our map. It is believed to be
the same band with that described in the second section of Connecticut
river, between Hartland and Fairlee. The range commenced again in
Rockingham, and is continuous thence to Brattleboro', Guilford, and
Bernardston, terminating in the north part of Greenfield, because covered
by the Trias. The last remnant of it to the south is represented upon my
father's map as situated in Whately. There are quarries of slate upon
this range in Dummerston and Guilford.

Observ^ers have not been agreed as to the age of this band. My father's
latest views led him to suppose these slates identical with those over-
lying the fossiliferous limestone at Mr. Williams's house in Bernardston ;

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 433

and hence that the whole series of rocks was presumably of the same
general age. Professor Dana has called specific attention to the differ-
ence in lithological aspect between the two slates, and is well satisfied
that the clay slate of West mountain is an earlier unconformable forma-
tion.* This is undoubtedly the correct view.

Commencing at the north end of this field of description, I will enu-
merate the position of the slates along sectional lines. First, in Brattle-
boro' and Chesterfield. In the west part of Brattleboro' village, the
Calciferous mica schist underlies the slates, both dipping 50° E. Farther
east the dip 60° W. has been observ^ed. At the depot the dip averages
66° south of east. At this locality I noted some interesting irregularities,
represented in Fig. 6S. The slates indicate an anticlinal dip, those at the
south end of the cliff being inclined at a less angle than the others, which
are vertical. Each side exhibits a band of quartz, sometimes bent and nod-
ular, but indicating an identity to the enclosing slates. Between them is
an older hard rock, separated distinctly by faults from the slates upon both
sides, showing most decidedly upon the south, both by divergence in dip
and a distinct fissure. This harder rock may not belong to an older for-
mation, but the layers certainly underlie the clay slates. On following the
ledge around to the village, it is seen to be much crushed and bent out of
place. I think many other ledges of slate would display similar irregulari-
ties if carefully studied. At the east end of the bridge over the Connect-
icut in Chesterfield the slates dip 80° N. 80° W. To the east of this the,
slates dip easterly, thus forming an anticlinal support to underlie the Coos
schist of Wantastiquit mountain. The synclinal is observable both north
and south of the Brattleboro' ridge. To the north are interesting bands
of quartzite, apparently elevated from beneath like the hard rock at the
depot just mentioned.

South of the Windham county agricultural park in Brattleboro' the
slates are minutely twisted, with the general dip of S. 70° E. The line
between them and the Calciferous group is crooked. At East Guilford
the Calciferous dips 55° E., followed immediately by the slates having
the same position. The roofing-slate band lies just to the east of the
village, and is supposed to stand at a higher pitch. Near the mouth of

* Avier. your. Set., iii, vol. vi, p. 343.
VOL. II. 55

434 STRATIGRAPHICAL GEOLOGY.

Broad brook in Vernon is an anticlinal in the slate ; and there is reason
to believe much of the rock in the neighborhood dips to the west. Fig.
69 illustrates the Broad Brook line.

Another sectional line, across school districts Nos. 4 of Guilford and i
and 2 of Vernon, is the following : In the valley of Fall river we find the
old slate quarry, that has been known for so many years. This is an
anticlinal valley, with dips of 80° N. 80° W. and jf S. 80° E. West
of it, in Guilford, is an extensive area of novaculite. There is also an
anticlinal, with similar steep sides, near school-house No. i of Vernon.
The most eastern outcrops of slate dip at a higher angle to the east
than the overlying quartzite. Between the two last sectional lines are
abundant slate exposures. The best known of these lines starts from
school-house No. 9, in Guilford, and crosses the slate ridge a little north
of east to Vernon Centre. This is shown in Fig. 70. At the school-
house and its vicinity is the quarry range, dipping 75° S. 20° E., with
its bosses of white quartz. On crossing the ridge to school-house No.
13, two bands of a white granitic rock, possibly conglomerate, separated
by slate, are passed. The last is at the more eastern school-house,
dipping south-east. Next succeed a few feet thickness of siliceous
limestone, like that belonging to the Calciferous. Associated with these
rocks by the school-house are feldspathic sandstones and felsites, and
talcose conglomerate. These conglomeratic, feldspathic, and calcareous
rocks occupy a breadth of less than a mile. They seem to belong to
some older group that is just touched by the erosion of the slates to form
the valley of Fall river. Passing into Vernon the older slates reappear,
with the usual easterly dip. Towards the top of the hill there is a west-
erly dip. A small anticlinal appears near the summit ; and the westerly
dip is restored on the crest of the ridge, and continues all the way down
the east side. The last ledge of it east of M. Lee's dips 80° W. The
first ledge of quartzite succeeding dips 30° N. 50° E. If these observa-
tions represent the mutual relations of these two formations, the latter
rests very unconformably upon the former. The slates of this ridge are
almost black, without lustre, and remind one of the darker slates of Blue-
berry hill, Littleton, formerly believed to belong to the Helderberg series,
but now referred to the Cambrian.

At about the crossing of the state line are slates, with a dip of S. 60°

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 435

E. 50°. Some of the layers are sandy. Near the line, on the west side
of Bald mountain, Bernardston, the dip of the black slate is 15° S. 50° E,
Clay slate occurs along this road for two miles north and south. At the
crossing of the state line by the back road from Vernon to Bernardston,
on top of the water-shed, twisted slates dip only 5° S. 20° W. — possibly
an abnormal position. On the west side of the road the dip is 70° S. 70''
W. A quarter of a mile south the slates dip 15° S. 50° E. on top of a
cliff, and then 50° E. A mile and a half east, on the line, we come to
an argillaceous schist, with staurolite on Pond mountain, which is supposed
to belong to the upper or Coos series. On passing to the "Basin" in dis-
trict No. 9, from the base of the hill, we find, first, a schist similar to those
holding imperfect crystals of staurolite, dipping east and north-east. This
is followed by a neatly-splitting slate, dipping 75° W. In the "Basin" the
rocks are slaty, twisted, with white quartz bosses, and a general inclina-
tion to the east. This locality is close to the town line. The hill west of
Fall river is composed of this same slate, including West mountain, where
the dip is 60° N. 86° E.

We see that foldings occur on all these sectional lines across the clay
slate, and that anticlinals are prominent. They may perhaps best ex-
press its stratigraphical structure, and that it unconformably underlies
the Vernon and Bernardston quartzite series of formations.

There is a singular interstratification of slates, with siliceous rocks, in
the north-east corner of Vernon, On passing to the north we find the
usual quartzite at the Hubbard place, opposite the location of old Fort
Bridgeman, dipping about 35° E. The range may be half a mile long
(No. 103). At Mrs. E. Howe's, by old Fort Sartwell, is an argillaceous
schist (No. 102). Just north of the Witch gutter the quartzite reappears,
with the same dip as before. The slates succeeding are much contorted
and broken, as if by pressure between the sandstones. Nos. 99 and 100
are quartzes, one hundred and thirty rods south of Broad brook ; No. 98
is a slate, ten rods farther north ; Nos. 96 and 97 are siliceous rocks, with
a little mica and iron, ninety rods south of the brook. From this point
to Brattleboro' all the ledges are of slate. These siliceous rocks may be
continued in the quartzites appearing on the east bank of the Connecticut,
just above the Brattleboro' bridge (Nos. 104 and 105).

43^ STRATIGRAPHICAL GEOLOGY.

4. Qltartzite.

The quartzites in the Helderberg area are gray, white, and bkie, in dif-
ferent localities, and are very abundant. They are often quite friable
sandstones, and again approximate to the usual vitreous variety most
common in the Coos group. Whether they belong to more than one
series, remains to be proved.

The first range to be described seems to skirt the Vernon and Hins-
dale gneiss area, bordering it almost everywhere. In the north-west part
of Hinsdale, about half a mile south of the Brattleboro' bridge, we find
bluish quartzites (Nos. 83, 84). At a quarry the dip is east. Farther
south it adds mica to its composition, and has a slaty color. At a shanty
near G. Thomas's is a little slate with it, dipping east, and then standing
vertically. The quartz continues along the river bank till we reach the
hornblende just opposite the mouth of Broad brook. It may strike
across the south-west spur of Wantastiquit mountain to the valley of Ash
Swamp brook. Nos. 71-75 represent the quartzite from one mile south
of H. Streeter's north to the line between Hinsdale and Chesterfield,
Daniel's mountain is composed of it, lying to the east of the stream (Nos.
^6, yy). Next we see it a little north of the saw-mill near S. Thomas's,
between Daniel's and East mountains. The dip is 60° N. 60° W., over-
lying hornblende schists, and followed by staurolite schist dipping east.
The map would seem to imply the existence of a separate range from
No, 71 to the saw-mill, resting upon the gneiss, and perhaps not connect-
ing directly with what succeeds. A little south of the summit of Bear hill
is an easterly-dipping quartzite, which has been traced more than a mile
a little west of south, just overlying hornblende rock. The range is seen
farther south, at A. H. Sumner's. Another exposure is in the east part
of the village of Hinsdale. We have no well defined quartzite along Fox-
den mountain, south of Hinsdale village, though its components are largely
of silica. The range may reappear on the south side of Great brook, with
the dip of 80° N. 30'' E. It probably crosses the Connecticut near South
Vernon bridge to join the quartzites at the railroad cut on the state line,
and also nearer the Connecticut. The dip may be 20° N. E. at the cut,
but much higher near the river. About two miles south of the Great
brook locality, at a saw-mill in Northfield, is a quartz conglomerate (No.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 437

89) which may be connected either with this range or another to be
spoken of hereafter.

Just out of the village of South Vernon, to the north-west, the quartzite
dips 20° N. 35° E. It is hkely this continues to join the quartzite far-
ther west, or No. 53, north-west from a brickyard near C. D. Severance's,
with the dip 25° S. 80° E. On the west side of this small hill is a sili-
ceous conglomerate, dipping 45° S. 80° E. I will not repeat the obser-
vations along the state line, where quartzite and hornblende rock alter-
nate, and will be noticed presently. It is not clear that the quartzite is
continuous from the railroad cut in South Vernon to the exposures near
Lily pond, though presumable. The quartz (No. 20) has a strike nearly
with the road, or north-westerly, between Lily pond and the state line.
Directly south from the pond there is a south-east dip, with irregulari-
ties. From here to the old fort in the north part of Vernon the outcrops
are easily traceable, curving from north-west to north, and then crossing
to connect with the quartzite in the north part of Hinsdale, The gneiss
east of the pond and along the direct road to Vernon is very siliceous,
and is with difficulty separable from it. Different observers would not
draw their boundary lines in the same place. By G. W. Lee's, in district
No. 9, the dip is east. Farther on, or near the school-house, the dip is
N. 48° E. Near L. C. Brooks's, the dip is 30° N. 50° E., but more east-
erly at the Hubbard place. This range invariably dips easterly, towards
if not beneath the gneiss. It is probably to be regarded as inverted, and
thus passing beneath the older rock, rather than resting unconformably
upon it.

The following is the order of rocks for two fifths of a mile in length,
from the edge of the alluvium in West Northfield, along the road nearest
the state line, illustrated by Nos. 143-156:

143, Quartzite, one fourth mile west of the 150, Breccia of quartzite and schistose
railroad,— dip, 60° S. 35° E. fragments,— dip, S. 35° E.

144, Micaceous quartzite — same dip, also 151, Argillo-mica schist,
dip of 60° S. 80° E. 152, Gneissoid quartzite.

145, 146, Quartzite, weathering as if from 153, Compact hornblende.

feldspar. 154, 155, Staurolite mica schist,— dip, 40°

147, Argillo-mica schist,— dip 70° S. 35° E. S. 45°-50° E.

148, Hornblende schist, — dip, S. 38° E. 156, Mica schist, much silica, and little stau-

149, Micaceous quartzite. rolite— quarried ; dip, 35° S. 30° E,

438 STRATIGRAPHICAL GEOLOGY.

Beyond this the rocks are covered for a quarter of a mile with gravel.
Then there is an indurated argillaceous schist, with many interlaminated
seams of quartz (No. 157), at a fork in the road, dipping 85° N. 40° W.,
and also near a deserted house.

For purposes of immediate comparison, I will introduce here the de-
scription of a section along the state line across this whole area, extend-
ing from Winchester to Guilford (Fig. 71). The previous section termi-
nates with No. 157, which is the point of intersection with the one about
to be described. The figures are taken from the catalogue of Section
I, as far as to Connecticut river.

66, White gneiss, near E. Lyman's, Win- 69, 70, Tourmaline schists, and

Chester,— dip, 20° N. 40° W. 71, Gneiss, dipping 40° N. 30° W.

67, 68, Decomposing gneiss,— dip, 25° N. 72, -ji, Ouartzites, vitreous and jointed,—

40° W. just east of tributary from the dip, 85° N. 25° W., and, in a few feet,

north emptying into Perchog brook. 75° N. 65° E.

The last named is on a hill constituting the high western bank of the
Perchog river. The gneiss is seen to pass directly beneath this quartzite,
both rocks retaining essentially the positions assigned above. It is there-
fore an excellent example of unconformity, as the quartzite is the younger
rock.

74, Mica schist,— dip, 80° E. and 80° W. 76, Mica schist, siliceous, half a mile west,

by school-house ; the same beyond. — dip 50° N. 30° E.

75, Coarse granite vein in 74, by S. H. 'j']. Micaceous quartzite,— dip, 45° N. 45°

Smith's. E. near C. Stebbins's.

With this (No. Tj) are layers carrying nodular veins of quartz, — ferru-
ginous and argillaceous strata. Nos. 74-77 are clearly the mica schist of
the Coos group. This is the last specimen obtained in Winchester.

78, 79, 80, Ouartzites, near W. Coombs's, Hinsdale, near Connecticut river, and dip-
ping 80° N. 30° E.

Next succeed the quartzites adjoining the river on the west side, 60°
N. 20° E., and at the railroad cut dip one third as much. The rock is
mostly quartzite, with mica schist layers of different degrees of coarse-
ness. The south end of the cut is gneissic, and there is a trap dyke here
also. In the road adjoining the cut is mica schist, dip N. 18° E. In the
field west is a large development of hornblende schist, dip about 48° east.

GEOLOGY OF TFE CONNECTICUT VALLEY DISTRICT. 439

Higher up are beds of micaceous quartzite, not very abundant, dipping
N. 60° E. These are followed by grayish-green hornblende rock, partly
actinolitic. A breccia was also noted between masses of hornblende.
The several bands following are these, in order : quartzose gneiss, horn-
blende, quartzose gneiss, hornblende, mica schist, dipping 40° S. 50° E.,
of considerable thickness ; hornblende schist, at the height of land, argil-
laceous and staurolitic schists, dipping 50° S. 58° E., and 45° S. 72° E.
This brings us to No. 157, an indurated schist, where the first road west
of South Vernon crosses the line. The relative thicknesses of these
several beds may be ascertained by referring to the published figure.

The eastern ends of these two sections are a mile apart, but they come
together at No. 157. Hence we may learn how the breadth agrees upon
the lines so near together ; and it is surprising to learn that the predomi-
nating rock along the state line is but slightly represented upon the other,
but the dips are everywhere the same. Two narrow bands of hornblende
rock are cut on the southern line, both of them combined hardly five
hundred feet wide ; on the other, at least one third part of the strata con-
sists of this material. The western bands seem to correspond with each
other, while we may say the eastern has narrowed extremely in proceed-
ing southerly, or else it is covered by quartzite and mica schists. The
latter is probably the better view, since the hornblende expands very
much to the south in Northfield and Gill.

Following our section along the state line, we find next a considerable
breadth of staurolite mica schist, thicker-bedded and more uneven from
contortion than a similar rock in Bernardston (No. 158). On the small
hill west of the road crossing the state Kne, the dip is 45° easterly (No.
160). In the deeper valley beyond, not traversed by a public road, the
dip is north-east (No. 161). This valley marks the place of an anticlinal,
the rock on the west side, and up to the summit of the steep hill-side
(No. 162), dipping 65° S. 20° W. This whole hill, known as Pond moun-
tain, consists of the same staurolite rock. The crystals are very small,
and in other respects differ from any found elsewhere in this Helderberg
area.

The rock for the three quarters of a mile succeeding has not been
examined. That next seen is at the crossing of the Bernardston road
over clay slate, where we have, first, by continuing the strike a short

440 STRATIGRAPHICAL GEOLOGY.

distance, 50°, then 5° S. 20° W. and 75° W. Then we have on the west
side of Bald mountain the dip 15° S. 50" E., and above Shattiick brook,
in the valley of Fall river, 50° S. 40° E.

The quartzites are supposed to be continuous from South Vernon
to the north-west part of Gill, passing through the south-east corner
of Bernardston. At the railroad crossing, in the south-west corner of
Northfield, the quartzite (No. 14) dips 25° S. E. immediately adjacent to
hornblende schist (No. 16) supposed to have the same dip. Near Pur-
ple's house, in the east part of Bernardston, we find a gneiss (No. 13) and
a conglomeratic feldspathic quartzite (No. 65), with well-defined quartz-
ites, all dipping about 30° S. 30°-40° E. Thirty or forty rods north-west
of this house are ledges of hornblende schist, dipping 70° S. E., extend-
ing very near to Purple's quarry. A section line from No. 16 to No. 139
(Purple's quarry), a part of Fig. 72, shows the same order of rocks as along
the state boundary. The same order may be obtained farther south-west.
The eastern mass of hornblende occupies much of Gill; and its junction
with the quartzite appears at the crossing of the north line of the town at
Unadilla brook, and at a fork in the road about a mile east of Otter pond.
No. 15 represents quartzose gneiss, a rock physically like quartzite, and
shown by Prof. Dana to have feldspar in it. The dip is i5°-25° S. E. On
the road north-westerly from No. 1 5 are outcrops of hornblende schist,
graduating into sienitic gneiss, dipping 15° S. 40° E. (No. 17), In passing
west, the next rock is the principal mica schist range (No. 138). The
quartzite range continues from this last sectional line, underneath a wide
expanse of gravel, to the neighborhood of Otter pond in Gill. About half a
mile's width of it may run between this pond and Fall river, dipping south-
westerly. It then passes out of sight beneath the Trias. At No. 68, west
of Grass hill, the dip is 30° S. 40° E., agreeing with the usual dip of this
formation, but near Fall river, along the line of strike, it has changed to
north-west. This fact may indicate the ])rcscnce of an anticlinal, not
commonly observable because inverted. This affords data for believing
this quartzite is the repetition of the bands, soon to be mentioned, north
of the village of Bernardston. All authors have assumed the identity of
the South Vernon range with that connected with the fossils. If so, the
connection is through folding and not by continuity, since the strikes are
different, as exhibited upon the map. P^or the benefit of any persons

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 44 1

disposed to doubt the reality of the connection, it may be said that all
the gneissoid quartzite of this region occurs along the eastern range, from
Otter pond to South Vernon, and is not found at all in connection with
the western range; also, the gneissoid quartzite is intimately associated
with hornblende schist, and is related to the Vernon gneiss; and all these
more crystalline layers are situated east of the pimpled mica schists with
staurolite. The fossiliferous locality is two miles distant, in the direction
of the dip from the nearest part of the South Vernon range. I have
separated areas of this gneissoid quartzite along the state line and east
of Bernardston village, upon the map, calling them Bethlehem, or the
equivalent of the Vernon area. I presume most of the quartzite, from
which these smaller areas have been separated, is essentially the same.
It is noticeable that hornblende occurs upon both sides of this range of
quartzite and gneiss, just as it encircles the Vernon and Hinsdale area
of gneiss.

The quartzite next the crinoidal limestone usually dips 25° S. 35° E.
The strike very nearly points to a school-house on the east side of Fall
river. A short distance south the dip is more southerly. It occurs also
a quarter of a mile to the north of the limestone (No. 64), and is verti-
cal, with westerly-dipping slates on the east. On crossing the valley, a
quartzite is found (No. 69) behind the first dwelling above the school,
running into the hill as if it were making for the corresponding rock in
the west part of Vernon. The strike is about N. 50° E., and the strata
are vertical. It may be followed for half a mile (No. 63). Part of the
way it presents a precipitous slope, with many reticulated quartz veins.
The debris at the base of the cliff is too great to allow a view of the lime-
stone, if it exists, in the place corresponding to its position on the west
side of the valley. The rock is largely white and bluish-gray, not very
granular, mostly vitreous. On crossing towards the back road to Vernon
the quartzite and slate dip south-easterly. Quartzite also appears south
of the school-house, at No. Gy. There are no other indications of the
presence of this rock in the north part of the town.

There is a second range of quartzite behind the limestone, towards

West mountain, possessing an easterly dip. I find, among observations

made in 1858, that there is a quartzite, dipping 60° westerly, some twenty

rods north of the limestone. There is also a westerly-dipping breccia a

VOL. II. 56

442 STRATIGRAPHICAL GEOLOGY.

few rods west. These may be spoken of again in the description of the
section upon this hill. After protracting these quartzites west of Fall
river, upon the map, none of them seem to connect directly with the
band east of the stream back of the school-house.

Little is known of the extension of the Perchog Brook (Winchester)
quartzite southward. I have noted it as having a westerly dip near the
north line of Northfield. The Massachusetts map represents a range of
it reaching to Miller's river, through Northfield and Erving. Starting
from the place where it is known to occur in Winchester, at a saw-mill
near F. Doolittle's, just in the edge of Winchester (Nos. 90, 91), there
is a quartzose conglomerate, carrying a little galena.

5. Coos Mica Schists.

We have at least three prominent varieties of these mica schists.
I. An ordinary mica schist, argillaceous, and containing crystals of stauro-
rolite. 2. Very siliceous mica schist, without staurolite. 3. Even bedded
slate, with and without staurolite. In this latter variety, this mica is
abundant in small, brown prisms, showing their faces where the strata
have been broken. Though resembling phyllite (chloritoid), it is likely
the mica is a phlogopite. Small red garnets are often present in great
abundance, so that when freshly fractured the surface of these slates is
covered with small pimples and pits. We have often, in the field, dis-
tinguished between the Coos and Cambrian slates, by observing the
presence or absence of these pimples. The distinction is not complete,
since the Guilford and Vernon slates are often much pimpled, yet belong
to the older series.

In Hinsdale and Winchester the mica schists carry beds of granite,
both coarse and fine grained. Other beds are of nearly pure quartz, of
mechanical origin.

Wantastiquit mountain is mainly composed of these mica schists which
are thought to overlie the quartzite range in the north part of Hinsdale,
already described. The strata on Bear hill dip easterly at a high angle ;
and the position all through the eastern part of Hinsdale is essentially
the same. These beds of granite show themselves in climbing Bear hill
from the north. Ashuelot river has cut through the ridge at Hinsdale
river, but it rises in Foxden mountain to fall again southerly in the south-

GEOLOGY OF TIO CONNECTICUT VALLEY DISTRICT. 443

west corner of Winchester. The dip is usually to the east. At Hinsdale
depot the dip is 60° E. By R. Smith's, three fourths of a mile south, it
is 70° N. 56° E., and it is nearly due east between the last two. More than
a mile south of the depot it is also to the east, by S. Doolittle's (No. 177).
There is a granite vein east of school-house No. 6, besides the one
already mentioned in Section I.

After crossing into Massachusetts the dips of the mica schists change
to the west, as No. 167; half a mile south of the line, a soft wavy rock,
inclined 80° N. W. A short distance further the schist is sandy, decom-
posing like siliceous limestone, almost vertical. East of Northfield vil-
lage, to the north and east of Mill brook, the mica schist is considerably
quartzose, dipping easterly. At Nos. 168, 170, the dip is irregular to the
north-west. It is about the same at 169. Returning by a more south-
erly route along Mill brook, we have, first, a northerly and then a west-
erly dip. No observations have been made farther south.

A branch from this range crosses the Connecticut to South Vernon
from about school-house No. 6 of Hinsdale. Between the Whithed ceme-
tery and the railroad crossing above school-house No. 4, of Vernon, are
several exposures of staurolite mica schist dipping 40° S. 50° E. and east.
The most northern and southern exposures have the first position named.
There is some hornblende rock between the most northern ledge and the
Vernon gneiss. Just in the edge of South Vernon is some mica schist,
the thinning out of this area towards the railroad junction.

Next we find the Bernardston area barely connecting with the mass
just described, through Nos. 165, 166. As alluvium covers the valley of
the outlet from Lily pond, we cannot be absolutely certain whether the
quartzites or the mica schists occur here. Before erosion, both may have
been here. Across the road from the limestone in gneiss (No. 11), mica
schist dips 50° S. 25° W. Next we find it on the state line section,
mostly dipping easterly, east of the road, and showing an anticlinal on
Pond mountain. From this mountain south-westerly to Fall river the
rock is mostly the pimpled mica slate. East of Bald mountain the dip
is south, then south-east. Near the end of a branch road (Nos. 128, 129)
there is a hard, siliceous rock, not well defined. The dip is usually small
to the south-east over all this area. It is last seen to the south-west,
about a mile north-east of Bernardston village.

444 STRATIGRAPHICAL GEOLOGY.

The relations of this group of strata are best seen in a section (Fig. 71)
from about the mouth of Couche's brook, a tributary of Fall river from
the west, across the supposed eastward repetition of the Williams quartzite
to Purple's slate quarry, and beyond. The Cambrian slates are believed
to dip about 50° S. E. along the west end of the section, beneath the allu-
vium of Fall river. The quartzite seems to stand vertical, and then to dip
south-east. The wrinkled schists cover it at the school-house, and dip 35°
S. 40° E. On the ridge west of Purple's slate quarry the dip is about
12° S. E. At the quarry the dip is about 20° S. E. About a stone's
throw to the south-east succeeds hornblende schist, dipping 70° S. E.
At the house are the gneissic quartzites, dipping about 30° S. E. At
No. 68 the dip is 30'^ S. 40" E., and the hornblende beyond is supposed
to lie in about the same position.

Our observations seem to establish a direct continuity of exposures of
these pimpled staurolite mica schists from the east foot of the Williams
hill, overlying the quartzites to Chesterfield, and consequently with the
extensive area of the Coos groups reaching to Haverhill. Hence it con-
firms the first part of the previous conclusion of Prof. Dana,* that the
" Coos group, which is but the northern continuation of the same [Ber-
nardston] series, is, if correctly traced out, also Helderberg." The refer-
ence here is to the mica schist division of the group.

6. Helderberg Limestone.

There is but a single exposure of this limestone, and therefore I will
carefully describe the jDOsition of the rocks associated with it. It occurs
upon the east slope of a hill a mile north-west from Bernardston railroad
station, and not over a fourth of a mile distant from ledges of the Trias-
sic sandstone. We enter through a gateway of Mr. Williams's from the
carriage-road, and encounter immediately a small knob of the blackish,
pimpled clay slate, dipping 30° S. 48° E. This is the western edge of
the Coos slates ; and in the field farther north it occurs with a high dip
to the north-west. Next succeeds the quartzite, dipping at first 29° S.
35° E., and then 25° S. 50° E. This is at a quarry. A hundred feet to
the south of the section line, and nearer the limestone, the quartz is more
vitreous, and dips 52° S. 40° E. In the field north of the section, in

* Amer. your. Set., iii, vol. vi, p. 349.

GEOLOGY OF TIiE CONNECTICUT VALLEY DISTRICT, 445

1858, I noted a quartzite dipping 60° N. W.; and in 1874 I observed a
ledge, presumably the same, standing vertically. Earth covers the imme-
diate junction of the quartzite and limestone; but as the latter dips ap-
parently beneath it, though at a small angle, it is so represented upon the
section. Yet the higher dips of the quartzite so near the limestones on
both sides may warrant one in suspecting the possibility of some irregu-
larity which should change our views of the relative ages of the rocks.
The limestone may be twenty-five or thirty feet thick, the place being
shown at No. 94. It abounds with fragments of crinoidal stems often
an inch across ; one end is frequently larger than the other. I have, also,
specimens of coral from it, quite obscure, which have never been sub-
mitted to a paleontologist. From the decomposition of the limestone a
considerable limonite has been formed, which was once manufactured into
pig iron. The limestone consists of carbonate of lime, 98.38; peroxide
of iron, 0.62; silica, i .00:= 1 00.00.

A short distance west of the limestone occurs a brecciated rock, com-
posed of fragments of quartz and slate, dipping apparently 25° W. This
is succeeded by a dark-colored quartzite having the same position. This
is followed by quartzite of the usual variety seen to the east, with a dip
rather more southerly than that. The length of the section, protracted
sufficiently to include the westerly band of quartzite, is eighty rods.

The observations from which our figure is constructed are mainly
those taken by my father in 1857 and by myself in 1858, and published
in the Vermont report. Prof. Dana has published a somewhat similar
figure in his sketch, to be mentioned presently. I do not speak of two
narrow argillaceous seams adjacent to the limestone, mentioned in 1858,
as they did not seem prominent in any later visits. I have examined
the section several times since 1858, once in company with Prof. Dana.
Some further remarks about this limestone, in its relations to the adjoin-
ing strata, will be appropriate after alluding to the opinions of my prede-
cessors.

Later Rocks.

The map shows an extension of the Triassic sandstone up the valley
of P^all river, reaching nearly to the limestone quarry. The slates have
probably been excavated across their edges transversely to form the basin

446 STRATIGRAPHICAL GEOLOGY.

for the sandstone, though the north-westerly dip of the quartzite, near
Otter pond in Gill, is suggestive of the existence of an underlying syn-
clinal. The area of the sandstone is much restricted from its representa-
tion on the Massachusetts map, in consequence of the discovery of the
harder rocks in Gill. The north end of the Trias in Northfield is com-
posed of a very coarse conglomerate, and is regarded as the uppermost
member of the series.

There are several lenticular-shaped drift hills in Gill and Bernardston,
noted upon the map, which may be regarded as ancient glacial moraines,
and therefore devoid of ledges. They constitute a feature in surface
geology hitherto overlooked; and their presence here makes it certain
that no ledges will be found upon their surfaces. Prof. Dana speaks of
seeing a ledge of gneiss upon one of these drift hills (D D' of his map),
which must be a loose fragment, though of large size. Another class of
drift deposits occur along the railroad east of Bernardston village, which,
equally with the moraines, obscure our knowledge of the ledges ; but
enough of the outcrops are visible to make clear how the solid strata
in the neighborhood of the fossiliferous band are to be grouped. The
alluvium is not represented except where it is so abundant as to conceal
the underlying ledges, and make it uncertain what formation properly
belongs there.

Catalogue of Specimens from the Helderberg Area.

In the museum the specimens are labelled looi, 1002, etc., to 1192, but
upon the map the figures commence with i, 2, etc. In all other respects
the map resembles those drawn heretofore to illustrate the Coos, White
Mountain, and Ammonoosuc districts,

BETHLEHEM GNEISS. 11, Limestone.

Vernon. Bernardston.

1, Gneiss, with much mica and pyrites. 13, 15, 65, Gneiss, very siliceous.

2, 5, 8, 12, 58, Granitic gneiss. Hinsdale.

3, Gneiss, very talcose. 20-27, 29-36, 39-43. 45- Granitic gneiss.

4, Hornblendic gneiss. 27a, Feldspathic gneiss.

6, Gneiss resembling Montalban. 28, Ferruginous gneiss.

7, Gneiss, with dark mica. 37, 38, Conglomerate gneiss.
9, 10, Gneiss, very siliceous. 44, Gneiss, very siliceous.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT,

447

HORNBLENDE ROCK.
Northjield.

1 6, 1 8, Hornblende schist.

19, Epidotic hornblende schist.
Bcniardston.

17, Hornblende schist.

Hinsdale.
46-43, 50-52, Hornblende schist.
49, Epidotic nodule in 48.

cm.

52 a, Hornblende schist.

QUARTZITE.
Vei'jion.
53-56, 57, 58 a, 59, 62, 70, Ouartzite.
57, Conglomerate.

Beriiardston.
14, 63, 64, 67-69, 93, Quartzite.
66, Quartzite, with mica blotches.

Hinsdale.
71-77, 81, 82, 86-88, Quartzite.

78, 83, Bluish quartzite.

79, Feldspathic quartzite.

80, Sandstone.

A^orthjield.
89, Conglomerate.

Winchester.
90-91, Conglomerate.
92, Quartzite.

HELDERBERG LIMESTONE.

94, Large crinoid, Williams's quarry, Ber-

nardston.

CAMBRIAN SLATES AND SILI-
CEOUS BEDS.
Verrion.

95, 98, 102, Argillaceous schist.

96, 97, Ferruginous quartzites.

99, loi, 103, Quartzite.

100, White quartz in 99.

Chesterfield.
104, 105, Quartzites, opposite Brattleboro\

Cidlford.
Ill, Conglomerate.

1 1 2-1 14, Conglomerate, with greenish min-
eral.
1x6, Sandstone.

117, Talcose conglomerate.

118, Reddish quartz.

119, Conglomerate.

120, Compact quartzite.

CAMBRIAN.
Bernardston.
106, 107, 127, Clay slate.

108, Argillaceous schist with 107.
131, 132, Wrinkled slate.

Cnilford.

109, Clay slate.
no, Novaculite.

l^ernon.

121, 122, 125, Argillaceous schists.
124, Blackstone.

COOS SLATES AND SCHISTS.
Bernardston.
128, 129, Siliceous micaceous rock.
130, 138, 140-142, Pimpled slates.
133-137, Argillaceous schists.
139, Staurolite slate — Purple's quarry.

Vernon.
163-166, Staurolite mica schist.

Northfield.
167-171, Mica schist.

Section along the road from West North-
field to the state line, and the?ice to the
second road crossing the line.

143, Quartzite.

144, 145, Micaceous quartzite.

146, Gneiss.

147, Argillo-mica schist.

148, Hornblende schist.

149, Micaceous quartzite.

150, Breccia.

151, Argillo-mica schist.

152, Gneiss.

153, Compact hornblende schist.

154, 155' 156, Staurolite mica schist.

448 STRATIGRAPHICAL GEOLOGY.

157, Indurated argillaceous schist. 178, Mica schist, coarsely crystalline.

158, Mica schist, with staurolite. 179, Mica schist— pyritiferous.

159, Indurated schist. Hinsdale— north of the village.

160, 161, 161 a, Staurolite schist. 182,184, 186, 189-191, Staurolite mica
162, Clay slate — second road crossing the schist.

state Jine. 183, 185, 187, Mica schist.

Hinsdale — south of the village. 1S8, Argillaceous schist.
172, 173. Quartzite. Chesterfield.

174, 175, 177, 180, 181, Mica schist. j^js, Granite, with plumose mica.
176, Staurolite schist.

History of Exploration.

This sketch will not be complete without extensive reference to the
writings of my predecessors in this field. The first notice of this lime-
stone I have seen in print is in the Report on the Geology, etc., of Massa-
chusetts, published by my father, in 1833, page 295. He says of it, —

Since the first edition of the first part of my report was published, I have had the
satisfaction of discovering organic remains of the family of encrinites in the bed of
limestone in Bernardston. From the highly crystalline character of this rock, I had
been led to suppose it older than the encrinal or transition limestone ; and that it
formed a bed in the argillaceous slate, which appears to be one of the oldest varieties
of that rock. But its organic remains settle the question of its position ; and, differing
in dip and direction from the slate, 1 have been led to doubt whether it really forms a
bed in that rock. The slate in the vicinity runs more nearly north and south, and the
dip is nearly 90° ; but the limestone runs N. E. and S. W., and dips S. E. not more
than 20°, Besides, the rock that is found above the limestone appears to be mostly
composed of quartz, and probably ought to be called quartz rock. It does not lie in
immediate contact with the limestone, nor is the slate visible immediately beneath the
limestone. Upon the whole, I am of opinion that this limestone lies beneath the oldest
variety of the new red sandstone series, which has been described, and upon the argil-
laceous slate, in an uncomformable position. * * * *

The encrinal remains in the Bernardston limestone are usually quite imperfect ; but
the transverse septa and the central perforation are generally distinct. Plate XIV,
Fig. 47, exhibits an end view of one encrinus, about an inch in diameter, and a view
of another lying horizontally in the rock.

No additional facts respecting the limestone appear in the final report
of 1 84 1. It is noticed in a brief paper On the Geological Age of the Clay
Slate of the Connecticut Valley, in Massachusetts and Vermont, presented
to the American Association for the Advancement of Science, in 1851 (2

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 449

vol., p. 299). The substance of the paper is, that this limestone has been
discovered to underlie a portion of the slate, and hence is thought to be
of the same age with it. The fossils were shown to James Hall, who
believed they might belong to the period of the Onondaga limestone of
New York ; at least, that they are not more ancient than that rock.

Thus we fix the age of this day slate as a part of the Devonian system, unless there
is some mistake in the observations or the opinions as to their character. If this
result be admitted, it does not follow that all the rocks of the Green and White Moun-
tains are no older than fossiliferous rocks, as some maintain ; for the slate formation in
the Connecticut valley is manifestly a newer rock than those which succeed, either on
the east or the west. Perhaps it is a portion of the Hudson River slate, which once
arched over the intervening Hoosic mountain, and which has been subsequently worn
away, except in this deep valley. * * * j \13_yQ met nowhere with rocks more
thoroughly crystalline than those which constitute most of the White Mountain ranges.
Gneiss, mica slate, and hornblende slates, just such as you find in the central Alps,
constitute most of the White Mountain ranges. * * * We shall be cautious in
admitting a conclusion [that the New England rocks are as new as the paleozoic] which
goes to the very extreme of metamorphism, without decisive evidence. We should at
least wait till the White Mountains have been more carefully studied.

Not far from this same year, the locality was visited by James Hall and
Sir Charles Lyell, but none of their publications add anything to what
has been already stated in this historical sketch.

A fuller account, with a section, is given in the geology of Vermont,
based upon my father's and my own observations made in 1858. They
have been given essentially without change in the preceding description
of the section (Fig. 72).

The fullest description of this region hitherto published was prepared
by Prof. J. D. Dana, and has been already alluded to. The facts of his
paper do not differ materially from my own, as given above, and I will not
quote his statements of the distribution and positions of the strata, but
present his conclusions. I feel very grateful to Prof. Dana for the interest
he has taken in this field. He perceived the true relations of the Coos
group to the mica slates of Bernardston before any one else; and it is a
pleasure to me to be able to confirm this conclusion by actually tracing
the Bernardston slates, ledge by ledge, to Chesterfield, and so on to
Haverhill, and finding them to be the same with what I have called the
Coos group in New Hampshire. If the Bernardston slates belong to the
VOL. II. 57

450 STRATIGRAPHICAL GEOLOGV.

Helclerberg series, it is certain the principal part of the Coos series must
go with them.

1. This Heidelberg series in central New England comprises a large part of the
common kinds of metamorphic rocks, gneiss, of several varieties, undistinguishable
lithologically from the oldest ; hornblende rock and schist ; sienitic gneiss ; coarse
mica slate ; staurolitic slate.

2. A large part of the rocks that have been distinguished as of the "Montalban" or
"White Mountain Series" in New Hampshire, and regarded as of pre-Silurian age, are
here included, and are hence nothing but altered Helderberg sediments. It is there-
fore far from true that " the crystalline rocks of the Green Mountain Series," and " the
whole of our crystalline schists of eastern North America, are not only pre-Silurian,
but pre-Cambrian in age." Hunt.

3. The passage of quartzite into gneiss is exhibited in different ways. The presence
of mica in the quartzite is one of the steps; but at the locality marked q [15] on the
map, part of the quartzite is very finely banded with white and gray. The white por-
tions are feldspathic, as is proved by their fusibility before the blow-pipe ; while the
light gray are cjuartz, and some short darker lines are micaceous. Thus this region,
like that of Berkshire, demonstrates that gneiss and quartzite are rocks of the most
intimate relations, — as intimate as anud and sand along sea-shore flats. Part of the
feldspathic layers widen at intervals into forms an inch or more thick at the middle,
but they are generally nearly even.

4. Hornblende rocks of the purest kind and of great extent are here so intercalated
with quartzite and mica slate, and so often graduate into one or the other, that all must
have been alike a result of the metamorphism of sedimentary beds. It is not possi-
ble that these hornblende rocks, constituting part of a Devonian or Upper Silurian
formation, should have come from the metamorphism of beds of a pre-Silurian, chemi-
cally-deposited, meerschaum-like hydrous silicate.

5. The Bernardston, South Vernon, and Northfield beds being of Helderberg age,
the Coos group, which is but the northern continuation of the same series, is, if cor-
rectly traced out, also Helderberg. Hence, in the era of the Lower Devonian, the
Connecticut valley, from the latitude of Bernardston northward, was an arm of the
sea, extending down from the great Devonian Gulf of St. Lawrence. Crinoids require
the best of ocean water, and thus they had it in central New England.

6. The Bernardston beds have been supposed to be Lower Devonian or Upper
Helderberg, on the ground of Hall's opinion, and also that of Billings's, recently ob-
tained. But both of these paleontologists speak of it only as the most probable con-
clusion from the fossils thus far found ; — they may belong to the Lower Helderberg or
later part of the Upper Silurian. According to Prof. Hitchcock, a slate containing
imbedded crystals of mica, just like that of Bernardston, occurs near Lake Memphre-
rnagog, where there are fossil corals of unquestionable Lower Devonian types ; and, as
the same slate follows the Cocis series through to that region, the lithological resem-

GEOLOGY OF TJIE CONNECTICUT VALLEY DISTRICT. 45 I

blance suggests identity of age, though not proving it without a further stratigraphical
study of the region between.

7. At Littleton, also, fifty miles south-south-east of Lake Memphremagog (S. 24°
E.), there is a limestone, half metamorphosed, containing Helderberg corals, — one of
the important discoveries of Prof. Hitchcock, to whom I am indebted for guidance
over the region. The limestone is associated with quartzite and clay slate, and also
with a series of chloritic rocks, partly feldspathic, including chloritic slate and a kind
of protogene, in which a pseudophite-like mineral is disseminated in small grains ; and
it appeared to me that all were conformable. If this conformability is sustained by
further observations, we shall have here the additional lithological fact that chlorite
rocks, including protogene, may constitute metamorphic beds of Helderberg age.

8. The facts which have been presented sustain the statements made on an early page
of this article, that lithological evidence of geological age is to be distrusted. If, when
used by one who has made it a special study, it leads to the conclusion that true
Helderberg xozVs in the White Mountain series are of Cambrian or earlier age, it is
surely a bad reliance. If it also makes out that Green Mountain rocks are of Huron-
ian age, or of some pre-Silurian period, when in reality belonging to the later part of
the Lower Stliiriatt, geologists may well be afraid even of its suggestions, unless it
have sure stratigraphical support. " Huronian" areas have been defined in various
parts of the country and the world on the basis of this evidence alone ; and in such
cases who knows anything whatever with regard to the real age of their rocks ? It is
probable that the rocks considered characteristic of the Huronian occur also among
true Laurentian terranes ; it is certain that they do in formations later than the Lower
Silurian.

Finally, what reason is there in chemistry or geology why crystals of andalusite and
staurolile should have been made only in pre-Silurian times? Andalusite consists
simply of silica and alumina, and staurolite of the same, along with iron. These three
ingredients are now and ever have been the most abundant of all the mineral constitu-
ents of the globe. With or without the iron, they are the materials of all clay depos-
its ; and clay deposits, from the decomposition of granite, gneiss, and related rocks,
have been forming all over the globe, and increasing in amount, ever since these rocks
began their existence. They are therefore the very last minerals that should be thought
of as pre-Silurian "fossils." Were zirconium, or any other of the rare metals a con-
stituent in the species, there would be some reason for suspecting their restriction to
the more ancient formations, since later sediments would contain only traces of them.
But silica, alumina, and iron belong to all time. These remarks apply equally to chlo-
rite, in which these three ingredients occur, with only a litde magnesia besides, and
water.

9. The epoch of disturbance, in which these Helderberg rocks of the Connecticut
valley were upturned and crystallized, was probably that closing the Devonian, when,
as Dawson and others have shown, extensive upturning, plication, and crystallization
of Devonian and older rocks took place over New Brunswick and Nova Scotia. It was

452 STRATIGRAPHICAL GEOLOGY.

the most prominent epoch of mountain-making on this eastern border of the continent,
after the Lower Silurian. Facts are against any earlier epoch ; and the only other
probable suggestion is, that the time was after the Carboniferous age, when the AUe-
ghanies were made. Hence the various Helderberg rocks of the Connecticut valley
have their actual date, as crystalline or metamorphic rocks, either from the close of the
Devonian or that of the Carboniferous era. The conclusions which have been pre-
sented are based on a foundation of facts, certainly as far as the region of Bernardston,
Vernon, Northfield, and Hinsdale is concerned, where my own observations were
made ; and, judging from the descriptions of Prof. Hitchcock, they appear to be sus-
tained as regards the Coos range to the north. Aiuer. Jour. Science^ iii, vol. vi, pp.
348-351.

Several other conclusions of a hypothetical character, relating more
especially to southern New England, follow the above, but do not need
to be quoted here.

Views of J. P. Lesley. Under date of October 27, 1858, Mr. Lesley wrote me, say-
ing he had obtained large crinoids and a possible CyathophyllH7ii from this limestone,
which had been sent to Prof. Hall for determination. "My Impression, from the
whole aspect of the ground, was, that I was on old and familiar ground, namely, V,
Vn, and VIII, with us, — Clinton and Helderberg, — but such impressions are never to
be trusted. The limestone may be Onondaga, and have a Cyathophylliim.''''

Conclusions.
Now that no further field-work is possible, I will state fully what con-
clusions seem to be warranted in regard to the order of all the formations
in this Helderberg area; how far their age can be determined from the
presence of the crinoidal limestone ; and what may be learned by a com-
parison of the rocks in the Helderberg and Ammonoosuc areas.

1. The porphyritic gneiss of Winchester is encircled by strata of the
Bethlehem group. Therefore the first is the older of the two, and, as we
shall see by further comparison, the oldest formation in the Connecticut
valley, as well as in all New Hampshire.

2. The Bethlehem gneiss in Hinsdale and Vernon is encircled and
overlaid by hornblende schist. The same has been observed in five or
six other areas, so that the relations between these two groups of rocks
in the Connecticut basin may be regarded as thoroughly understood.
Hence, whenever the hornblende seems to underlie the gneiss, we know
that it has been inverted.

3. Quartzite encircles the hornblende. Hence, as the relations of the

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT, 453

hornblende and Bethlehem gneiss are well understood, the innermost be-
ing the oldest, it follows that the quartzite is newer than the hornblende
schist. It may be there is more than one quartzite in this field ; but
none of the authors who have written about these rocks have assumed
the existence of quartzite of more than one age.

4. There was probably a long interval between the period of the depo-
sition of the hornblende and quartzite, so that there is an unconformity
between them ; and the presumption is, that the quartzite west of the
hornblende in Vernon lies upon the latter, both strata dipping easterly,
and the former may not be inverted. The possibility of inversion here
has been suggested heretofore. The clay slates of West mountain and
Guilford are universally admitted to underlie the quartzite unconform-
ably. Therefore we have both the period corresponding to the strati-
graphical break, and the time occupied by the deposition of the clay
slates, to represent the interval between the quartzite and hornblende
schist. The quartzite has also been mentioned as unconformably over
the hornblende east of Otter pond in Gill. The superiority of the quartz-
ite to the gneiss, in the absence of the hornblende, is well shown on the
Perchog river in Winchester (Fig. 71).

5. It is well agreed, also, that the Coos slates overlie the quartzite.
This appears from the section at Mr. Williams's (Fig. 73); from the rela-
tions of the quartzite east of Fall river to it (Fig. 72); and from many
sections that have been described in the other Connecticut areas. Mr.
Huntington has come to the same conclusion in his essay upon the rocks
between Charlestown and Chesterfield.

From these conclusions, others of importance follow.

6. The Coos slates, starting from the Bernardston plain, cross trans-
versely the clay slate, quartzite, hornblende schist, and Bethlehem gneiss
before reaching the Chesterfield deposits of the same age, which extend
uninterruptedly thence to Haverhill, embracing the typical area of this
name in Hanover, Lyme, and Orford. Hence it is the newest of all the
several series named.

7. It follows that there are important inversions in this whole field,
where no one would suspect their existence without a previous knowl-
edge of the facts now set forth. Perhaps the most singular is that of the
Coos slates between Fall river and South Vernon. They dip at a very

454 STRATIGRAPHICAL GEOLOGY.

small angle, yet must be inverted along their eastern border (Fig. 71); and
they may possibly fold over the quartzite by the school-house opposite
Williams's (Fig. 72). The quartzite range is also inverted ; — it hes between
two hornblende bands, all three dipping south-easterly. Hence it must
constitute an inverted synclinal. There is the possibility, however, that
there may be a band of the Bethlehem gneiss between these hornblende
areas. I have so called them upon the map, but would prefer the con-
clusions of Prof. Dana, that we must not rely too strictly upon lithology;
and, as by his conclusion (3) gneiss and quartzite are rocks of the most
intimate relations, we may say that the very quartzose gneiss of this range
is not of Bethlehem but of Coos age. As once before intimated, the horn-
blende schist of Northfield may be regarded as the repetition of two bands
of the same rock to the east, and of the Leyden and Shelburne Falls
groups farther west, though some of them may be apparently monoclinal.
Furthermore, many of the easterly-dipping mica schists in Hinsdale and
Winchester may be regarded as inversions, particularly near their eastern
border. I cannot now state all. the overturns existing in this area.

8. It is not so easy to be sure of the repetitions of the quartzite, yet
the following seem probable : On the east we have the range from the
Perchog river in Winchester through Northfield. This must pass under
mica schists, and come up in the range at Doolittle's saw-mill, at South
Vernon and West Northfield, which passes south-westerly into Bernards-
ton and Gill. These ranges are connected naturally and obviously, the
dips not being inverted. The next repetition is the range near a school-
house, a mile north of Bernardston. Though it seemed to point directly
to the quarry back of Williams's, the discovery of the northward contin-
uation of the latter makes any connection between them improbable, save
by a synclinal fold beneath the valley of Fall brook. Then, if there is
but one band of quartzite, there must be a repetition of it upon the Wil-
liams section (Fig. 73). The dips that have been observed show a ten-
dency of the rocks to conform to this position. The north-westerly dip
of this rock in the north-west part of Gill indicates a connection between
the Williams Hill range and that east of Fall brook (Fig. 74). We find
here, also, that all the dips along the eastern border of this largest range
are not inverted.

9. Next will follow the most singular of all our conclusions, the proba-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 455

bility that the crinoidal Hmestone occupies a small valley in the quartzite,
and therefore would be newer rather than older. In other words, it may
be the newest rock in this Helderberg section, resting upon the quartzite,
instead of underlying it, as is commonly represented. Whether it may
not crop out somewhere between the quartzite and Coos slates, remains
to be seen. There is nothing in its relations, if correctly interpreted,
rendering this an impossible position. The quartzite and slate in the
field north stand vertically and dip west. Though the limestone at the
quarry seems clearly to dip under the quartzite, we must not forget that
the state of things is entirely different close by. That this limestone
should bear the structure of an inverted synclinal may seem strange, but
it is not any more singular than many similar exposures of Chazy lime-
stone in the Champlain valley, as shown conclusively by the presence of
fossils. Lesley's views seem to confirm this opinion.

This view agrees with the interpretation given heretofore regarding
the related rocks in the Ammonoosuc area. There the quartzite under-
lies the limestone in many exposures. In that region the staurolite slates
nowhere touch the Helderberg. In fact, a conglomerate associated with
the crinoidal layers contains fragments of a rock supposed to have been
derived from the development of Coos schists not very far away, but
separated by a well-marked Huronian ridge. There is nothing in the
relations of the same two rocks in Bernardston to prevent us from inter-
preting them in the same way, /. ^., to regard the slates as much older
than the limestone.

10. Granting that the staurolite slates of Bernardston are the southern
end of the Coos group, it does not follow that the latter are of Helderberg
age, as Prof. Dana supposes ; for we have first to prove that the former
are so intimately associated with the limestone as to be necessarily of
the same age. These slates nowhere touch the limestone, so far as
known. They are separated by the quartzite.

1 1. Nevertheless, the Coos rocks are the newest in the whole Connecti-
cut valley north of Massachusetts, unless it be this fossiliferous limestone.
Provided some intimate connection can be made out between them, — and
there is plenty of ground to work over in search of the paleontological
evidence, — they may all be regarded as Helderberg. There is nothing
incongruous between a Helderberg Coos series and the doctrines laid

456 STRATIGRAPHICAL GEOLOGY.

down in previous chapters regarding the great antiquity of most of the
New Hampshire rocks.

12. In case the Coos schists are to be regarded as of Helderberg age,
the whole of the Calciferous mica schist must be taken with them. These
occupy about a third of the area of Vermont, and such reference would
add much to the breadth of Paleozoic areas in New England. This was
very nearly the view of Logan, of twenty years since, who supposed that
this formation belonged to the Niagara group.

13. There is no connection whatever between the Coos and Montalban
groups, as is inferred by Prof. Dana. If we grant the former to be Hel-
derberg, it does not bring the latter any higher up, since all the White
Mountain rocks have been shown to underlie them unconformably.

14. There is no interstratification of the chloritic rocks at Littleton
with the Helderberg. There may be a few small bunches of chlorite in
the limestone. Chlorite is a mineral that may exist wherever rocks have
been elevated and permeated by fluids transporting the proper chemical
reagents. Its presence does not indicate a high degree of metamorphism.
The chloritic rocks do not come anywhere near the Bernardston series,
so that it is clear they do not belong to the Helderberg series, even upon
the most comprehensive definition of them.

15. It is probable that the epoch of elevation of the Helderberg rocks
along the Connecticut valley occurred in middle Devonian times. We
find at Mcmphremagog lake the upper Helderberg limestone, and also
elsewhere in northern New England, but no later groups. In the east
part of Maine I have found Helderberg strata, elevated at a considerable
angle, overlaid unconformably by Hamilton beds. It is presumable that
this epoch of elevation in Maine may correspond with that in this valley.
I am persuaded it was an epoch of elevation of the greatest importance,
perhaps more so than any other that has manifested itself in New Eng-
land. (See page 263.)

16. Interpreting the facts as above to harmonize with what seems well
established about the older New Hampshire rocks, it is clear that we may
still eliminate the thoroughly crystalline schists from the catalogue of
Paleozoic formations ; and, conversely, the Helderberg rocks have not
been very much metamorphosed, even if we refer the Coiis rocks to that
age. Staurolite and andalusite may be found anywhere, because their

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 45/

constituents are universally common, as explained by Prof. Dana ; so
that their presence does not argue a high degree of metamorphism.

j^F:E'Ei>rjDx:K. to csi^i^tek, iat.
TiiE HuROXiAN System.

On page 267 I have promised at this place to discuss the claims of the Huroniaii
system to recognition. It will be done briefly, while our comparisons must extend over
a very wide territory.

In the large geological map of the United States, prepared in conjunction with Prof.
W. P. lUake for the Smithsonian Institution, and exhibited in Philadelphia at the
Centennial Exposition, seventeen areas of the Huronian system west of the St. Law-
rence river are represented, irrespective of those along the Atlantic border.

The first use of the word Huronian I find is in the Esqidsse Geologiquc du Canada,
prepared by T. Sterry Hunt for the Paris Exposition of 1855. It is represented as
being a series of grits, schists, limestones, conglomerates, and diorites, reposing un-
conformably upon the Laurentian, and lying beneath the Silurian. It is said to hold
about the position of the lower Cambrian of Sedgewick. The area from which the
name was derived lies upon the north shore of Lake Huron. A section from the Lau-
rentian outcrop on the main land opposite Drummond island, and running a little
north of west to Lake George, would pass in succession through all the members
of the series. I find these overlaid by the St. Peter's (Chazy) sandstone, according
to Logan.

The following is a section of the Huronian rocks from this typical locality, as derived
from the geology of Canada, 1863, and the accompanying atlas, wherein the distribu-
tion of the several members is clearly represented with colors.

Feet.

/. White quartzite, chert, and limestone 2,100

k. Yellow chert and limestone, 400

/. White quartzite, ......... 2,970

//. Red jasper conglomerate, ....... 2,150

g. Red quartzite with greenstone ; ripple marks, .... 2,300

f. Upper slate conglomerate, 3,000

e. Limestone, with diminutive contortions, 300

d. Lower slate conglomerate, with greenstone, .... 1,280

c. White quartzite, 1,000

b. Green chlorite slate, 2,000

a. Gray quartzite, 500

18,000

This typical locality does not enable us to restrict the limits of the system so closely
as may be done upon the south side of Lake Superior, in the northern peninsula of
VOL. II. 58

458

STRATIGRAPHICAL GEOLOGY.

Michigan. The underlying rock is the same, but it is covered by the " Copper series,"
a group of strata devoid of fossils, and situated beneath the Lake Superior sandstone,
which is now commonly esteemed as the equivalent of the Potsdam. The Huronian
is therefore older than the fossiliferous Cambrian.

Huronian System of Michigan.

The latest studies in this region have been made by Messrs. Pumpelly, Brooks, and
Wright, and are described partly in the report upon the geology of Michigan, and
partly in special papers, by Major T. B. Brooks, in the American Jo7irnal of Science.
I accept these latest studies as the best. The system is divided into twenty parts, and
I give in parallel columns the specifications concerning their nature in the two best
known districts, Marquette and Menominee. The Huronian is said to be distinctly
unconformable to the Laurentian.

'Marquette Region.

XIX. Mica schist, with staurolite, an-
dalusite, and garnet ; quartz, in bunches,
and rare hornblende seams.

Ouartzite, and probably soft slate.

XVII. Anthophyllitic (?) schist, usually
magnetic and manganiferous.

XVI. Banded ochrey porous quartz
schist.

XV. Blackish argillaceous slate, rarely
micaceous, occasionally with garnets.

XIV. Gray arenaceous quartzite ; quartz
conglomerate.

XIII. Hematite and magnetic ores;
banded jaspery schist, and beds of chlo-
ritic and hydro-mica schists.

XII. Red quartz schist, with banded mi-
caceous iron ; quartzose limonite ores.

XI. Diorite, hornblende schist, chlorite
schist, chloritic-looking mica schist ; rare-
ly hornblende gneiss.

X. Hematitic and limonitic schists, of-
ten manganiferous ; siliceous schists ; gar-
netiferous, anthophyllitic schists.

Menominee Region.

XX. Granite and gneiss.

XIX. Mica schist, with staurolite and
hornblende schist — rarely gneiss — chlorit-
ic schist ; granitic dykes.

XVIII. Quartzite, with chloritic, mica-
ceous, and argillaceous schists and slates.

XVII. Chiefly hornblende schist and re-
lated greenstones and chloritic schist.

XVI. Chiefly clay slate, often ferrugi-
nous ; also hydro-magnesian schists ; mi-
caceous quartz schists ; hematite schists ;
rarely hornblende rocks and greenstones.

XV. Gabbro or diabase, with green-
stones ; ferruginous and actinolitic schists.

XIV. Unctuous hydrous magnesian
schist ; sericite, quartzite, and chloritic
greenstones.

XIII. Chloro-argillaceous slate, chlorit-
ic schist, diorite, carbonaceous slate, and
anthophyllitic schist.

Hornblende rock and chlorite mica
schist.

Micaceous clay slate (phyllite), with
seams of quartz ; carbonaceous slate.

Whitish dolomitic marble, with
tals of tremolite and wollastonite.

crys-

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 459

IX. Hornblendic rock, diorite, and dia- Clay slate, quartzite, mica schist,
base.

VIII. Ferruginous quartzose flags ; clay Hornblende schist,

slate and quartzite.

VII. Hornblendic rocks. Hydrous magnesian schist and probably

ferruginous clay slate.
VI. Ferruginous quartzose schist, clay VI. Hematite schist and siliceous flag
and chloritic slates. ore ; ferruginous clay slates ; hydrous mag-

nesian schist; rarely granite dykes.
V. Quartzite verging into protogene ; V. Dolomitic marble ; rare beds of

beds of dolomitic marble ; novaculite ; quartzite and hydrous magnesian schist.
rare chlorite and mica schist ; sienite, di- IV. Arenaceous magnetic mica schist.
orite, diabase, hornblende schist, con- III. Soft schist, not made out.

glomeratic quartzite and quartzose iron II. Ouartzites, arenaceous, micaceous,

ores ; talc schist. and actinolitic. Ripple-marked.

I. Protogene gneiss ; hydrous magnesian
schist ; schistose conglomerate ; quartzite
and diorite.

Major Brooks devotes much attention to Nos. XIX and XX of the Huronian as they
occur in Wisconsin, just over the Michigan line.* Though the rocks resemble the
Laurentian, he is satisfied they occur above all the other eighteen Huronian members,
while lying unconformably beneath the copper-bearing series, which he calls Keiveiiaw-
ian. Readers of our New Hampshire geology will recognize the resemblance between
these youngest Huronian rocks and our Coos or possibly the Montalban series. The
position at the summit of the Huronian is in exact agreement with the place of our Cods
group. This resemblance is sufficient to attract the attention of observers, and to give
new interest to the determination of the New England groups.

Brooks estimates the thickness of the Menominee groups (exclusive of XX) at 12,000
feet, and only half that amount in the Marquette region. Steatite and serpentine are
rare in these Michigan rocks.

The Huronian in New Brunswick.

Under the name of Coldbrook, Messrs. Matthew and Bailey describe rocks of this
age near St. John, in New Brunswick. They are the following :

Upper Coldbrook.

b. Red and greenish-gray argillites, 170 feet.

a. Red sandstones and conglomerate.

6. Gray feldspathic sandstone, beds chloritic schists, conglomerate.

* Amer. your. Sci., iii, vol. xi, p. 206; also vol. xii, p. 194.

460 STRATIGRAPHICAL GEOLOGY.

Lower Co I db rook.

5. Greenish-gray clay and micaceous slates, with slaty dolomite.

4(5. Feldspathic and dioritic sandstones, with chlorite and epidote.

4«. Sandstones, chloritic schist, diorite, and especially petrosilex.

3. Fine gray dark diorites.

2. Pinkish or white felsites, and feldspathic quartzites, \ . , . ,

^ ^ \ half a mile thick.

I. Diorites, )

In other sections of the jDrovince the red felsites and dolomites are both more promi-
nent than in the Coldbrook series above.

Views of Thomas Macfarlane.

Allusion has been made (vol. i, p. 532) to the views of this gentleman, erroneously
said to be James, who is well known for his book on the Coal Regions of America.
Mr. Thomas Macfarlane thinks he was improperly referred to by Dr. Hunt, and has
taken the pains to state his views concisely in the Canadian Naturalist for 1871. He
commences by remarking upon the incongruity of Logan's map, in representing by a
single color the metamorphic Quebec group of Eastern Canada, the Calciferous sand-
stone, and the upper copper-bearing rocks of Lake Superior. I will quote from what
he says respecting the Huronian and Cambrian rocks of Canada, which of course applies
equally well to our Connecticut Valley Huronian, their southern continuation.

" In referring to the gneissic series of the Green Mountains, Dr. Hunt makes mention
of my having, in 1862, 'ventured to unite it with the Huronian system.'* I am not
aware of ever having done this, nor do I think that there are even good lithological
reasons for assuming the identity of the two series. In the paper referred to by Dr.
Hunt, in which I instituted a comparison betwixt the rocks of Norway and Canada, I
endeavored to point out the resemblance between the rocks of Tellemarken, or the
quartzose group of the Urschiefcr, and Sir W. E. Logan's Huronian series, as devel-
oped on the north shore of Lake Huron. As differing from these, I expressly distin-
guished the Dovrefjeld slates, the schistose group of the Urschiefer, and pointed out
their resemblance to the semi-crystalline schists of Vermont and Eastern Canada.
The lithological differences betwixt the Tellemarken rocks and the Dovrefjeld slates in
Norway are just as decided as between the Huronian series and the Green Mountain
schists in North America. Enormous beds of quartzite, and perhaps felsite and pecul-
iar conglomerates, characterize the Huronian, while micaceous, chloritic, and argilla-
ceous schists and serpentines distinguish the Green Mountain rocks. It may be that
these differences are not sufficient to justify us in regarding them as belonging to differ-
ent formations, but they would seem to afford grounds for distinguishing them as
groups. Therefore in my paper on the subject f I have separated the quartzose from
the schistose division of the Urschiefer, the former and not the latter being identified
with the Huronian. If it were considered advisable to distinguish the Green Mountain

* Dr. //tint's Address, p. 33. f Canadian Natura/ist , vii, 161.

GEOLOGY OF T^IE CONNECTICUT VALLEY DISTRICT, 46 1

rocks as a separate formation, it would seem to me most advantageous for the science
to use the term Cambrian for this purpose, as has ahxady been done by eminent geolo-
gists, and as I propose to do on the present occasion.

" The Cambrian SystExM. In studying the various geological formations which pre-
sent themselves in Canada, it is impossible to avoid comparing their architecture, lithol-
ogy, and mineral contents with the same or similar formations in European countries.
Any one who has had an opportunity of observing them will at once perceive that not
only do the Dovrefjeld slates resemble our eastern townships rocks, but also that the
primitive and transition rocks of Saxony have much in common with them. Moreover,
in examining the manner in which the eastern townships rocks succeed each other, the
analogous order of the schists of the Erzgebirge at once presents itself to the mind,
and suggests ideas as to the respective ages of the corresponding rocks in Canada.

" When the traveller in the Saxon Erzgebirge mounts the steep escarpment which
borders that range of mountains towards Bohemia, passes northward up the valley of
Joachimsthal, and stands at last on the ridge overlooking to the south the valley of the
Eger, with Carlsbad in the distance, he has entered the primitive region of Saxony,
rendered classical in geology by the labors of Werner and his successors. If the jour-
ney is continued northward, by Annaberg, Elterlein, and Lossnitz, to Stollberg, gneiss,
mica schist, and clay slate formations are passed over successively, and at last une-
quivocal sedimentary and fossiliferous formations arrived at. The order of succession
of these schists of Saxony afforded the foundation for the law, long ago propounded by
Werner, that mica schist forms the lower, and clay slate or its substitutes, chlorite and
talc schist, the upper part of the Urscldcfcr. Further, since the mica schist, in those
districts where the primitive formations are present in all their completeness, is found
to be supported by gneiss, it follows that in the architecture of these oldest rocks the
three groups of gneissic, micaceous, and argillaceous schists succeed each other in
ascending order. It must not, of course, be forgotten that in some instances one or the
other of these groups may be absent ; — those which are present, however, always show
the order of succession here indicated.* This is observed not only in the Erzgebirge,
but also in the Fichtelgebirge, the Siideten, the Riesengebirge, Scotland, Ireland,
Norway, and Hungary.

" Turning now to south-eastern Quebec and the states adjoining it, we find that fol-
lowing the line of the Grand Trunk Railway north-westward, the succession of primi-
tive and even transition strata occurring in the Saxon Erzgebirge is repeated. After
leaving the granite and gneiss of New Hampshire, we cross the mica schist district of
Compton county, and then chlorite and clay slates from Sherbrooke to Richmond.
From the latter place, through the townships of Durham, Acton, and Upton, green and
grayish slates, graphitic slates, grauwacke sandstone, and gray limestone, in strata more
or less highly inclined, are traversed. All this time the country becomes less and less
hilly, the rocks less and less frequent, until near Britannia mills, or, still keeping in a

* Naumann, Geo^noz:e, ii, 155.

462 STRATIGRAPHICAL GEOLOGY.

north-west direction, near the village of St. Helene, the wide-spread alluvium of the
St. Lawrence valley is reached, occupying an area of several thousand square miles, in
which very few rock outcrops are observed. This area is said to be underlaid by the
Utica and Hudson river formations, which again are said to overlie conformably the
Trenton and Chazy limestones, and the Calciferous and Potsdam sandstones. All
these rocks form part of a series of sedimentary strata occupying certain areas in the
valley of the St. Lawrence, lying horizontally or nearly so, and supposed to be of Lower
Silurian age. The Potsdam sandstone is the lowest member of this group of strata,
and is regarded as the oldest Silurian rock, and possessing even greater age than the
mica schists and clay slates of the eastern townships. Indeed, in the attempts which
have been made at determining the age of the latter rocks, it has always been the rule
to begin with the Potsdam sandstone as the oldest rock, and to assume that those to
the eastward (regardless of their lithological characters) followed each other in ascend-
ing order. Any one who has studied the structure of similar regions in Europe, such
as those above mentioned, can scarcely fail to come to the conclusion that the opposite
of this assumption is the truth ; that the oldest rocks are those of New England, and
that, as we come north-westward, we pass over more and more recent strata. This
view would be maintained in spite of the prevailing dip to the south-eastward, which
can only be accounted for by assuming, with Emmons, that the strata have been over-
turned,— this, and indeed the plications of the whole series, having been caused by
some enormous pressure from the south-east.

" In distinguishing the Green Mountain series. Dr. Hunt seems to have been unable
to leave the beaten track, in which he had previously travelled, and to regard the more
eastern crystalline rocks as the older instead of the newer. He still adheres to the
idea that the Green Mountain rocks, because they apparently underlie the White
Mountain mica schists, etc., are the older rocks. In referring to the Laurentian sys-
tem, it has been shown how entirely inconsistent with European experience this sup-
position is.

" In the preceding section the opinion has been expressed that Dr. Hunt has gone too
far in asserting the pre-Cambrian age of the Green Mountain schists. In maintaining
their pre-Silurian age, however, he merely adopts a view advocated by myself as early
as 1862. In describing the Dovrefjeld slates, and comparing them with similar rocks
in the Quebec group and Green Mountain series, I made the following remarks :
' Different views prevail, as to their age, in different countries. In Cornwall they are
considered Devonian ; in Scotland, Lower Silurian ; and in Bohemia, as in Norway,
pre-Silurian, In Belgium, Rhenish Prussia, Westphalia, and Nassau, they are by some
geologists regarded as Devonian, and by others as belonging to an older formation.
In East Russia, on the western slope of the Ural Mountains, they are supposed to
represent Lower Silurian strata. A dissimilarity of views will probably continue to
prevail as to the position of these rocks until the question is decided as to what value,
in the absence of fossils, the petrographical characters o'f a group, taken in connection
with its stratigraphical position, should have in determining its age. Perhaps there

GEOLOGY OF TTIE CONNECTICUT VALLEY DISTRICT. 463

prevails at present too much of a tendency to attribute extraordinary influences to met-
amorphic agencies. So soon as tlie true limits and effects of metamorphism are
recognized, it will probably be acknowledged that whatever view may be entertained
as to their origin, the schistose rocks above referred to underlie the Silurian and all
7in altered or j/ietatjwrphosed fossiliferous strata.''^''

The Huronian of Quebec.

In consequence of the changes of opinion respecting these rocks in the more west-
ern area, or that represented upon Plate I and mentioned upon page 12, it is difficult
to estimate the proper succession and thickness of the several members. Sir W. E.
Logan has described them under the general name of Quebec group, with three divi-
sions. He has grouped together a large series of fossiliferous Cambrian and metamor-
phic rocks, assuming that the one was the equivalent of the other. I have endeavored
to separate the fossiliferous from the metamorphic portions, with the assistance of Dr.
T. Sterry Hunt, upon Plate I, though it may not be so easy to decide between the
bands as belonging to the one or the other series. On page 12, I have stated that the
western band of Huronian extends to the end of the peninsula of Gaspe. That is an
error. After eliminating the fossiliferous portion, the metamorphic area is found to
reach only about as far east as the city of Quebec, and it is properly represented upon
the map, and there is also a small isolated area near the end of the peninsula. The
line of the Bayer and Stanbridge anticlinal is the proper division between them.

Logan's classification, as derived from the report upon the geology of Canada for
1866, is the following: The lower or Levis series consists of limestone, black shales,
gray shales, dolomites, and conglomerates, amounting to 6,145 feet for the maximum
thickness. This carries numerous graptolites and other fossils distinctly belonging
to the region of the Calciferous and Chazy.

The middle or Lauzon division is marked by a predominance of green, red, and
purplish shales, with thickness ranging from 100 to 6000 feet. Two brachiopods occur
in it. The metamorphic portion is bounded by two magnesian bands, dolomite, soap-
stone, or serpentine. Logan supposes the soapstone and serpentine are altered dolo-
mites. These two bands are accompanied by beds of metallic ores, particularly of
copper. Of the three synclinal areas, the most western is regarded as unaltered, and
the two eastern as true Huronian. The second synclinal carries chlorite and epidote,
which are wanting in the first or Paleozoic basin. Other rocks are talcoid schists,
greenish micaceous sandstone, nacreous slates, etc. The third synclinal is like the
second lying east of the Green Mountain range. The upper or Sillery division, unal-
tered, consists of greenish (slightly calcareous) sandstone, passing into fine conglom-
erates, about 2000 feet thick. The metamorphic portions are chiefly epidotic and
chloritic schists and quartzites.

From this series, as proposed by Logan, we must eliminate all the fossiliferous por-
tions, and invert the order. The fossils known to occur in the unaltered formations
agree to this reversal, and we find the Sillery and Lauzon groups correspond to the

464 STRATIGRAPHICAL GEOLOGY.

older Cambrian of England, and the Levis to the Skiddaw slates, or the lower part of
the Cambro-Silurian of America. This view renders it unnecessary to regard these
fossiliferous groups as at all connected with the proper Huronian, or the rocks of the
two eastern synclinals ; but it shows that inversion is the rule for these rocks near
Quebec, and therefore the rocks east of the Sillery are older. This is in agreement
with the recently quoted view of Mr. Macfarlane, and has been also insisted upon by
Dr. Hunt.*

Separating the eastern part of the area called Quebec group by Logan, we may
clearly understand it to be older than the fossiliferous Cambrian of any part of the
world, and therefore to be named Huronian, unless we adopt the suggestion of Mac-
farlane. He is probably correct in referring this eastern portion of the Quebec group
to the upper division of the Urschiefer, in distinction from the lower, which may be the
same with the Michigan rocks. But instead of calling the upper division Cambrian, it
is better to say Upper H2ironian ; and, if further examination confirms the suggestion
that none of the upper division is to be found about Lake Huron, we may call that the
Lower Huronian. Where it is not possible to define between the upper divisions, it
will still be proper to use the general term for the whole. Our statements respecting
these rocks in New Brunswick indicate the presence of the felsites of the lower divi-
sion with the more argillaceous upper group.

The Vermont Huronian.

The Vermont Huronian, save that along Connecticut river, is the southward contin-
uation of the Quebec group of Canada. It is divided into two parts by the central
ridge of the Green Mountains, which continues a few miles into Canada.

Macfarlane follows the report on the geology of Vermont in regarding the Green
Mountain ranges as older than the adjacent Upper Huronian. We have in that early
publication (1861) insisted that these Green Mountain rocks underlaid the green schists
upon both sides (see p. 31), and they are consequently older. The name Green Moun-
tain gneiss, as applicable to this formation, was in use in 1846; and therefore the use
of the same geographical designation by Dr. Hunt, in 1871, for the Huronian, is both
inappropriate and improper, on account of prior usage. The Green Mountains are not
Huronian at all, though flanked by it upon both sides in the northern half of Vermont.
They belong to the Montalban series. Adopting the principle of inversion, as applied
to the members of the Quebec group, we find they overlie these Montalban gneisses
in the proper order of succession. As Macfarlane says, those who once accepted the
theory of the metamorphism of New England seem to retain erroneous notions of the
age of the successive mountain ranges, calling the Green Mountains newer than the
Adirondacks, and the White more recent than the Green. They are both nearer the
Laurentian than the Huronian, in respect to age.

* Chemical and Geological Essays, p. 613.

GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 46$

HuRONiAN IN New Hampshire.

We seem to have in the Connecticut Valley area at least three groups, — the Lisbon,
Lyman, and auriferous conglomerate. To this should be added the SwiftWater series,
giving a thickness in all of 10,269 f^^t- The volume of these rocks is greater in Coos
county. The rocks present a greater similarity to the lower Huronian than those of
the Vermont area next the mountains.

We have yet to consider a great thickness of rocks in the south-eastern part of New
Hampshire, consisting of quartzites and mica schists. These seem to us to be related
to the Upper Huronian, and may be thus described in the later chapters of this book.
These extend into Massachusetts, where are also developed very plainly the felsites of
the Lower Huronian. The porphyries of the White Mountain district resemble them,
and would be classed as Huronian, I suppose, by Dr. Hunt.

Huronian of the Atlantic States.

These same rocks occur at intervals in Connecticut, New Jersey, Pennsylvania,
Maryland, Virginia, North Carolina, South Carolina, Georgia, and Alabama. Litho-
logically, they agree with the areas mentioned in New England. Observers do not
agree in referring them to the Huronian. Geologists are beginning to study them, and
therefore will gradually accumulate the means for their final and correct determination.

Fig- 75- — SECTION OF DISTORTED PEBBLE, LEBANON, ONE HALF NATURAL SIZE.
VOL. 11. 59

CHAPTER V.

THE GNEISSIC AREA FROM LANDAFF TO THE SOUTHERN BOUNDARY OF

THE STATE.

BY J. H. HUNTINGTON.

IJOiHIS area embraces the entire western part of the Merrimack Valley
J% district, and its western limit corresponds with that of the dry land
in the Labrador period, as marked on a map in Volume I, opposite page
528. The rocks that bound it on the west are the quartzites and mica
schists of the Coos group. On the east the limit is generally the por-
phyritic gneiss, except towards the south, where it embraces the whole
of Cheshire county. The line that bounds the area on the west runs
nearly parallel with the Connecticut river ; that on the east is not so
direct, yet it has the same general direction as that on the west.

Along the western border, at intervals where the newer rocks are
included in this district, there are mountains of considerable elevations,
as in Orford, Dorchester, and Grantham. Elsewhere the country is high
above the sea-level, and rises in hills of varying height. East of this
the common gneiss forms the central part of the area, and in places
extends to the western border, the country nowhere rising into hills of
very great height ; but in parts of Warren, Wentworth, and Dorchester
the country is generally high, while in the eastern part of Unity and in
Lempster, it forms an elevated plateau-like area. East of the common
gneiss, a fine-grained gneiss, — forming a transition state into mica schist.

GEOLOGY OF THE MERRIMACK DISTRICT. 467

and generally carrying fibrolite, — is the rock of some of the highest
mountains in this district. East of Baker's river we have Mt. Carr and
the ridge extending southward, that terminates so abruptly in Rattlesnake
mountain west of Rumney. Southward we have high hills and moun-
tains : Plymouth mountain, in Plymouth ; Mt. Crosby, in Hebron, from
the summit of which we have such a fine view of Newfound lake ; Tenney
hill, immediately north, and the high land in Groton ; then we have, south,
the deep valley of Cockermouth brook, and the high hills between this
and the north-east branches of Mascomy river, and south of these the
porphyritic gneiss of Mt. Cardigan. The water-shed then descends to
the famous notch in Orange cut by the Northern Railroad. In Grafton,
the country everywhere is high ; Isinglass hill, Alger's hill, where the
immense beryls are found, Ford hill, a little south-west of the last, and
Prescott hill, are the most noticeable points ; — they vary in height from
1600 to 1800 feet. The ridge which we have followed, if it appears in
Springfield, except in the extreme northern part, is not prominent above
the general level of the country. It appears, however, again southward,
in a high ridge in the east part of Goshen ; also, in Lempster mountain,
and still farther south in Surry mountain. The country in the south-east
part of Cheshire county and along its southern border is everywhere high
land, having an average of at least a thousand feet above sea-level. Well
marked hills are not very numerous ; hence Monadnock is one of the
most prominent mountains in the state, as the view in every direction is
unobstructed. In the east part of Winchester, in the west part of Rich-
mond, thence northward in Swanzey and extending into Keene, are round
hills and mountains composed cheifly of gneiss. The depression in this
area seems to have the general direction of north-west and south-east,
though there are others not so well marked in other directions. It is to
be noted, however, that they pass through nearly all the varieties of rock.
The following are the prominent groups of rocks noticed, in what appears
to be their order of superposition, beginning with the lowest :

1. Porphyritic Gneiss, for the most part, forms the eastern boundary of
the area we propose to describe; but it has outliers in the south which
extend to the western part of the district.

2. Bethlehem or Protogene Gneiss. This rock varies somewhat in tex-
ture and composition in this area. That in Enfield is very closely allied

468 STRATIGRAPHICAL GEOLOGY.

to that in Bethlehem, and it has been often described. South, where it
occurs in Grantham and Unity, and in the more extended area in Ches-
hire county, it is generally finer-grained. The feldspar is often reddish,
and it sometimes contains hornblende ; the chlorite is in places abundant,
but elsewhere there is little, or it is wanting altogether. In general, how-
ever, its lithological characters are such that the rock is easily recognized.

3. Coinmon or Lake Gneiss. In the north part of the area it has uni-
formly a remarkably coarse texture, and is composed largely of quartz
and black mica, and generally the mica is quite abundant.

4. Ferruginotis Concretionajy Schist. This is largely developed in the
south-east part of Cheshire county. It is a siliceous schist, nearly every-
where pyritiferous, and frequently contains brilliant garnets in imperfect
crystals. It is sometimes plumbaginous, and, as in Nelson, it contains
extensive beds of plumbago or graphite.

5. Fibrolite Schist, sometimes gneissic and passing into common mica
schist. It is often thick-bedded, and is characterized by having immense
veins of coarse granite along its entire outcrop.

6. Quartzites and Quartz Conglomerates. These are evidently of the
same age as those of the Connecticut Valley district.

7. Intrusive Rocks and Veinstones.

Laurentian Series.

Porphyritic Gneiss. The lithological characters of this rock have been
so often described in preceding pages, that it is not necessary to repeat
the description here. It is characteristically developed in Ellsworth, to
the north-west of Stinson pond; in Rumney, at the north end of Stinson
mountain ; on Mt. Cardigan ; also, in Sunapee, Stoddard, Marlow, Chester-
field, Winchester, Hinsdale, and Rindge. In Canaan there are crystals
of feldspar ; but the general character of the rock is that of the common
gneiss. The area north-west of Stinson pond is in the forest; and on
both sides of it we have fibrolite schist. In Ellsworth it outcrops on
Moulton brook, where the road crosses it at H. & D. Sanborn's mill.
The strata appear to be vertical. Here, also, we have mica schists and
a fibrolite on the west. Both outcrops, however, are some distance from
the mill. Going east, the next outcrop of porphyritic gneiss is near G.
Avery's, in the road, probably sixty rods west of the house. Here it

GEOLOGY OF THE MERRIMACK DISTRICT. 469

comes in contact with the fibroHte schist. It is nearly vertical, but at
one point it dips N. 70° W. 78°. South-west of Avery's, in the edge of
Rumney, partly in this rock and in a "trap" dyke, there is a mineral vein
that carries galenite. From what I was able to see, it appears to be a
very promising lode.

On the north end of Stinson mountain there is an outcrop of porphy-
ritic gneiss in the pasture farthest up that side of the mountain, and it is
entirely surrounded by the schist. In the south part of Groton the gneiss
has a few crystals of feldspar, but it does not seem to be the characteristic
porphyritic gneiss. Farther south, in Alexandria, there is no doubt about
the character of the rock, and it is entirely east of the fibrolite schist.
The small area of gneiss in the west part of Canaan that contains crystals
of feldspar probably belongs to the common gneiss, since in its general
foliated texture it does not differ from that rock elsewhere. From the
line of Canaan and Orange, the western boundary of the porphyritic
gneiss runs a little to the east of south through Grafton and Wilmot to
Pleasant pond in New London ; then it turns a little to the west, and in
Sutton it turns almost directly west, and goes to Sunapee lake. At Sun-
apee Harbor, and on the hill immediately south, we have the porphyritic
gneiss associated with a rock that resembles the White Mountain gneiss,
and the dip is easterly 70°. North of Sugar river. Straw's ledge in Suna-
pee is porphyritic gneiss. In the vicinity of Sunapee lake we frequently
have fine-grained granitic gneiss that evidently belongs to this series of
rocks. South, on the road from Goshen to Washington, opposite J.
Glinn's, we have a fine-grained gneiss enclosing bands of porphyritic
gneiss; thence south-east, towards Washington centre, there are gneisses
and pyritiferous and mica schists ; but the rock in the south and east
part of Washington is chiefly porphyritic gneiss, and a band extends into
the north-east corner of Marlow. Its north-western limit is near Sand
pond, and the line separating it from the rocks on the north-west runs
south-west, probably between F. M. Lewis's and school-house No. 3,
thence bending a little north, and extending to a point near the upper
part of the letter L of the name of the town on the country map ; thence
it sweeps round to the south-east, nearly to the road south of Bald moun-
tain. Its south-eastern limit would be marked by a line extending from
the south-east base of Bald mountain, and crossing the road running

470 STRATIGRAPHICAL GEOLOGY.

north through Marlow, a mile and three quarters above the village.
There are ledges near the road, and it is almost the only rock on the road
from C. D. Symonds's to Ashuelot pond in Washington. It is the rock
of Huntley mountain, south of Sand pond, and it is probably continuous
to Bald mountain, and this appears to be its south-eastern limit. The
rock north-west of the porphyritic gneiss is mica schist, containing im-
perfect crystals of andalusite ; on the south-east and south we have gneiss,
at first fine-grained, but coarse as we go southward.

Going southward, the next area of porphyritic gneiss is included in
the towns of Chesterfield, Swanzey, Winchester, and Hinsdale. This
area is wholly in the topographical district we are describing. It forms
the high, rough, and rugged portions of the towns where it is found. Its
northern limit is about a mile and a half south of Spofford lake in Ches-
terfield. It soon widens and sends off an outlier into Swanzey. It ex-
tends south into Winchester, and has its southern limit about three and
a half miles from the state line. As a whole, the area is oval in shape,
and in a line east and west it extends from near Kilburn pond in Win-
chester to within a mile of the Ashuelot river. The road from Chester-
field to Winchester, except for the first mile, passes over a country where
this is the underlying rock. On the road from Chesterfield to Ashuelot
village, there are many outcrops. Near its northern limit, not far from
D. L. Sanderson's, there are many ledges ; and on the road near Crouch's
saw-mill, in the south-east part of Chesterfield, there are numerous out-
crops. In Swanzey, near H. Albee's, is a porphyritic gneiss; and here
it has a fibrolitic schist interstratified with it, but in a way that seems
to show that the schist is the newer rock. Some of the boulders of por-
phyritic gneiss here contain fibrolite, which has not been seen in this
rock elsewhere. This band of gneiss extends north to school-house No.
6, and as far south, at least, as the road that runs past M. Riley's. It is
possible that this band may be separated from the rock west, in Chester-
field, by a band of schist. Where the porphyritic gneiss is found on the
road directly west of Winchester village, the crystals of feldspar are
flesh-colored, — a characteristic that is not common in this rock. Where
the Ashuelot river has cut a deep, broad ravine through this rock, the
stream is rough and rapid ; and as the many boulders with which the
channel is lined resist the current, and the water is poured over and

GEOLOGY OF THE MERRIMACK DISTRICT. 471

around them, the noise of the rushing and tumbhng of the waters equals
some of our fierce mountain streams. South of the Ashuelot river, on
the road that runs west from Ashuelot village, the porphyritic gneiss ex-
tends to the edge of Hinsdale. South-west of Ashuelot village there is
an outcrop, near the house of C. Wise, and this is near its southern limit.
The rock in this area, as well as that in Marlow, is nearly everywhere
stained with iron. Near the central part of Fitzwilliam there is a limited
area of porphyritic gneiss. At Dr. S. Cummings's, we find a characteris-
tic variety. West, near the railroad, and just north of the granite quar-
ries, there are several outcrops, and the one north of the Richmond road
and east of the railroad is quite extensive. Some boulders on the road
from the station to the village enclose rounded masses of the dark gneiss
that is quarried on the Richmond road and below the station. There
may also be an outcrop on the east side of South pond. From the
State Line station on the Cheshire railroad, going north, we have White
Mountain gneiss, dipping north-westerly ; this is followed by a fine-
grained gneiss, and this in turn by a band of well-marked porphyritic
gneisses which extend to Sip Pond hotel, while northward are granitic
gneisses of the White Mountain series.

In Jaffrey, south-west of Gilmore pond, near A. Emery's, there is a
small area of prophyritic gneiss. In Dublin, south of Monadnock pond,
there is an isolated hill near W. Phillips's, where the crystals of feldspar
are much smaller than those found elsewhere in the porphyritic gneisses ;
here they are not much more than a quarter of an inch in thickness, and
three quarters of an inch in length. The same rock outcrops near P.
Morse's, and it is associated with a pyritiferous schist, but interstratified
with it there is a dark, fine-grained gneiss. The dip of the porphyritic
rock is N. 8° W. 35°, and the pyritiferous schist is unconformable with it.
The rock in the south-east part of the town has many of the lithological
characteristics of the porphyritic gneiss, though the large crystals of feld-
spar are wanting, and it resembles the gneiss of Bradford. In the north-
east part of Dublin, and extending into Harrisville, the gneiss is porphy-
ritic. At J, Gilchrist's are many ledges, and there are outcrops along
the branch of Contoocook river to the outlet of North pond. Its western
boundary extends from near the forks of the road above school-house
No. 9, a little west of north, to D. French's, south of Long pond ; thence

4/2 STRATIGRAPHICAL GEOLOGY.

it extends northward through Nelson, and in the north part of the town
it outcrops near M. Wilson's. It then extends north through the central
part of Stoddard, thence into Washington, and probably dips under the
common gneiss, to come up again in the narrow Marlow range. In the
east part of Stoddard, as well as in the east part of Washington, there
are not only numerous ledges of porphyritic gneiss, but in many places
there are boulders of immense size. In the study of this rock we have
found in Ellsworth that there are areas of it surrounded by fibrolite
schist, and that on the east it is unconformable with the schist ; that in
Orange, the relation of the two rocks are not certain, as they do not
come in contact; that in Sunapee, we have detached masses, on both
sides of which are micaceous and granitic gneisses of White Mountain
series, — and the same fact has been observed in Fitzwilliam ; that in
Marlow, it has, on the south and south-east, gneisses that cannot be re-
ferred to either of the well-marked divisions of the rocks; that in Ches-
terfield and Winchester, it has at least on one side the common gneiss ;
and that in Jaffrey, Dublin, Nelson, and Stoddard, it is associated with
a siliceous pyritiferous schist, that is found not unfrequently in basins
of the porphyritic gneiss. The fact that rounded fragments of a dark
gneiss are found in the porphyritic shows that the porphyritic rock in
Fitzwilliam is either intrusive, or that in the process of metamorphism
these fragments were not obliterated, and that the dark gneiss — which
is very limited, but resembles some varieties of the Bethlehem gneiss —
is the older rock.

The Bethlehem or Protogene Gneiss, and the Common or Lake

Gneiss.

The common gneiss enters this topographical district from the north,
and its western limit coincides very nearly with the western boundary of
the Atlantic or gneissic period, as represented on a map in Vol. I, opposite
page 516. It extends a little more to the west in Westmoreland; and
although in Hinsdale the rock is a gneiss, it does not seem to be the
common variety ; and, as already noted, the rock from Chesterfield south-
ward is porphyritic gneiss. The eastern boundary is for the most part
definite and easily traced, and the rock bordering on it is a fibrolite schist.
It extends southward through the cast part of Landaff, through Benton

GEOLOGY OF THE MERRIMACK DISTRICT. 473

along the side of Moosilauke, far up its western slope, through Warren
along the steep slope of Mt. Carr, and extending south it crosses the line
between Wentworth and Rumney near its southern terminus; then it fol-
lows near the line of Dorchester and Groton, then runs just east of the
west line of Canaan, thence southward, near the west line of Grafton.
In Springfield it is not so well defined, but is probably about a mile west
of the old Sulloway tavern. In Sunapee it is not far from Union church,
on the road from Sunapee Harbor to Newport. In Goshen it runs nearly
parallel with the road that goes south through the east part of the town, —
generally a little to the east of this road. From Goshen it turns west-
ward, and runs south along the west slope of Lempster mountain, thence
south-east nearly to East Alstead. Though the boundary is not well
marked through Alstead, yet in Surry it is again well defined. South-
ward, the boundary becomes more indistinct again ; and the rock on the
east verges into the micaceous and granitic gneisses of the White Moun-
tain series, and the line turns somewhat to the east, running almost
directly to South Keene ; thence southward, and crosses the Cheshire
railroad just above Marlborough depot, when it goes south near the line of
Swanzey and Troy. After it reaches Richmond, it turns suddenly to the
south-west, and strikes the line of Richmond and Winchester a mile and
a half north of the state Hne, and leaves a small area of White Mountain
gneiss in the south-east part of Winchester. Between this line through
Richmond and the porphyritic gneiss in Winchester, we have for the
most part the Bethlehem or protogene gneiss, though it differs from the
gneiss in the northern part of the area we have described. We find also
several areas of protogene, which are contemporaneous with or older than
the common gneiss.

Protogene Gneiss. This is found along the western border of the com-
mon gneiss in Haverhill and some of the towns south. It is quite unlike
that found in Grantham, Keene, and some of the adjoining towns. In
the latter the feldspar is often flesh-colored, and sometimes it largely
predominates. We find elsewhere a large proportion of quartz ; then we
have a greenish mineral, probably chlorite, — certainly not mica. If the
chlorite is wanting, mica, when present, is in minute scales, and collected
in patches through the rock. The protogene gneiss, known as the Beth-
lehem gneiss of the northern part of the topographical district of the
VOL. II. 60

474 STRATIGRAPHICAL GEOLOGY.

Connecticut valley, has been already described, so we shall notice only
that which is found east of the main range of the quartzite.

The lithological characteristics of the northern variety of the proto-
gene or Bethlehem gneiss have been pointed out so often that it will not
be necessary to repeat them here. When this rock occurs east of the
quartzite, it is not always easy to tell where it ends and where the com-
mon gneiss begins. A characteristic variety of the Bethlehem gneiss
is found in Hanover and Canaan, to the east of Moose mountain ; and a
fine-grained variety extends northerly into Lyme. The whole forms an
oblong area, the northern limit being near the saw-mill north of the old
Holt tavern, and its southern, near the village of Enfield. On the south
it is compact, rather thick-bedded, contains quite a large proportion of
flesh-colored feldspar, and it is quarried in the north-east corner of Han-
over and in the south-west corner of Canaan. Northward, especially in
Lyme, it becomes quite friable and crumbles easily, and it is separated
from the protogene area westward by a band of quartzite. The water-
shed between the Mascomy river and Goose Pond brook is probably
the limit of this area eastward in Canaan. Other areas of the protogene
gneiss that occur along the north-west border of the common gneiss, that
have not already been described, will be noticed with the common gneiss.

In Grantham, west of Croydon branch, we find a reddish protogene
gneiss that is quite different from the protogene gneiss northward ; it is
much finer-grained, is cut by numerous joints, and in it here and south-
ward there are intrusive bands of quartz. It extends from the road north
of D. S. Hastings's southward to the road running north-west from Croy-
don east village. The principal band, however, of this rock begins in
Surry, across the ravine south of George Joslyn's, and extends through
the edge of Keene and Westmoreland into Chesterfield to the forks of
the road south of J. Putnam's. The first prominent outcrop is south-east
of G. Grain's : at first there are few quartz veins ; then south the rock
seems to be almost entirely quartz; but west of C. Wright's we have
ledges of protogene ; and cast of school-house No. 4 we find in basins
of this rock the mica schist which is so common to the north-west.
The reddish gneiss, — for the protogene character of the rock is not
always apparent, — is cut by the railroad in the south-west corner of Surry,
and below, at the first crossing in Kcenc. In the latter cut we find, going

GEOLOGY OF THE MERRIMACK DISTRICT. 475

west, — (i) gneiss ; (2) quartz bands, with well defined walls (the rock is
very much jointed, and resembles a dyke) ; (3) we have a chloritic rock ;
(4) we have the intrusive quartz repeated. In the Surry cut we have
hornblende schist, which terminates abruptly at the line of a fault, and
there is a slight change in the inclination of the strata. The inclination
of the fault is about 70° easterly. At the line of the fault we have a band
of quartz twenty or thirty feet wide. The inclination of the strata of the
hornblende schist is very nearly the same as that of the gneiss ; so we
have simply a downthrow of the rocks at the east end of the cut. It is
the best defined of any fault that we have found, and it is shown in Fig.
80. Here, as in this quartz elsewhere, there are some fragments of gneiss
included in it. Gneiss begins abruptly against the quartz, and going
west the inclination of strata is aj^parently quite variable, — generally,
however, about 15° v/esterly, but more inclined as we go west. There
are several quartz veins penetrating the gneiss, and in one of these pyr-
rhotite was found. On Gray's hill, a little west of south from the Surry
cut, the protogene gneiss is found on the summit and westward, and it
is probably continuous from the railroad. It is here cut by the intrusive
quartz veins ; — the strata seem to be nearly horizontal, and resting on it
are hornblende and chloritic schists. The protogene gneiss occupies the
entire western part of Keene, except where it is covered by other rocks.
It is also found on the western slope of the hills east of the central part
of the city of Keene, just west of the road along Beech hill. Hence it
is altogether probable that this rock underlies the drift across the valley
of the Ashuelot from West mountain to Beech hill.

Besides the rocks on Gray's hill there are outcrops a mile south-east
of the Wilson farm, half way from school-house No. 12 (of the county
map, now No. 7) to the railroad crossing, near D. B. Stearns's, at G. Per-
ry's, and on the hills both north and south along the Chesterfield road
from Keene west of the railroad. On West mountain there are extensive
outcrops ; but the reddish protogene rock disappears in the north part of
Swanzey, but the rock southward does not differ very much from some
varieties of the protogene northward. From the eastern slope of West
mountain, in the broad valley of the Ashuelot, we find only drift until we
ascend the hills on the east side of the valley, where there is a decom-
posing gneiss, probably the common variety of this section in the Beth-

476 STRATIGRAPHICAL GEOLOGY.

lehem gneiss. A section across the valley shows the protogene, and the
rocks associated with it. In Westmoreland the gneisses occupy nearly the
whole of the south-east part of the town. The principal rock is the pro-
togene gneiss ; but the boundary between it and the common gneiss has
not been determined. The limits of the gneisses westward, and the prin-
cipal places of outcrop, will be noticed further on ; but the rocks of the
south-east part of Westmoreland deserve especial notice. The following
is the succession of rocks from Samuel Gordon's, just south of the Barker
place, to A. Parker's ; and it seems more than probable that they occur
here in their natural order, without having been overturned, and without
having been pushed very much one over the other. The older rocks
form a basin in which these were deposited. Going north from Samuel
Gordon's, we have (i) protogene gneiss, — dip, N. 74° W. 22°; (2) horn-
blende schist, containing nodules of epidote, — dip, N. iq'^ W. 12°; (3) at
J. Tilden's, a foliated and wrinkled gneiss, — dip, N. 9° W. 10°; (4) at D.
Hyland's, quartzite, — dip, N. 10° E. 16''; (5) forty rods north of Hyland's,
a wrinkled mica schist, with staurolite, dipping N. 80° E. 8°. At Parker's
there is a hornblende gneiss, resting on a protogene gneiss, which dips
N. 60° W. 25°. These rocks are entirely surrounded by protogene gneiss.
A section showing the relation of these rocks can be seen in Fig. 79.

Protogene gneiss occupies the north-east part of Chesterfield, and
it is succeeded on the south by porphyritic gneiss, and on the west by
argillaceous and mica schist and quartzites. North-west of the gneiss
there are staurolite, siliceous, chloritic, and other schists. On the south-
east there is mica schist, generally fine and even in texture, while with
the gneiss there are hornblende schists and quartzites.

Common or Lake Gneiss. The common gneiss occupies the central
and south-western parts of Landaff. The gneiss varies greatly in text-
ure. In the area between Easton and E. E. Merrill's it is coarse and
granular, with an abundance of black mica ; but south of Cooley hill it is
somewhat finer, and at the forks of the road from Easton and the old
road from the McConnell place, it is followed by mica schist. Where the
Easton road crosses the Wild Ammonoosuc there is gneiss, and it outcrops
three fourths of a mile east of Danville. Northward, on Cobble hill, we
have a hard, greenish rock, probably diorite. It is so jointed that the
stratification cannot be determined with any certainty. North of Cobble

IPzu\.nri] XX.

— Illustrations of Chapter V. — .^

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Vertical Scale, 1500 Feet to an Imch.

Horizontal • , I Mile " » >• —

V\tV\0'^y VL

GEOLOGY OF THE MERRIMACK DISTRICT. 47/

hill, on the road turning to the left, about fifty rods east of J. T. Gale's,
in the gneiss, is a vein containing iron. This is crossed by a coarse
quartz vein. Near the house there is a fine-grained gneiss, which seems
to pass into a granular quartzite ; and in this is a large vein of quartz.
Near J. Clough's there is a fine-grained gneiss ; and west of Green moun-
tain there seems to be a granitoid gneiss. To the north there is a fine-
grained, thick-bedded gneiss as far as the south side of Pond hill. South,
three quarters of a mile from Clough's, we cross a band of quartz ; then
we have gneiss, — a dark, fine-grained variety. Still south, at an abandoned
iron mine, we have gneiss, which extends into the edge of Bath and out-
crops on the hillside east of J. Mann's. Along the road, on the north
side of the Wild Ammonoosuc, the first gneiss that is seen has a more
distinct, foliated texture than is common to the great body of the gneiss
in this section, and the quartz in it seems to be more abundant. The
thickness of this band is, however, quite limited. The gneiss, which is
fine-grained, continues nearly to D. N. Page's, where we have a band of
quartzite, and this outcrops nearly half a mile north of Page's. The
gneiss outcrops again east of Page's; and at L. W. Hubbard's we have
a chloritic rock. At Mrs. W. Grant's we find quartzite and a dark, fine-
grained gneiss ; then, eastward, there is gneiss, as already noted.

In the north-west part of Benton the prevailing rock is gneiss, between
the quartzite and Tunnel brook. East of the quartzite, near D. Howe's,
we have a narrow band of hornblende gneiss that contains nodules of
epidote. This band may be the source of those immense crystals of epi-
dote that have been found in the south part of Benton and in Warren.
East of the hornblende rock we have gneiss, and it extends south to the
height of land. East of the road south of the height of land the rock is
coarser than the gneiss in general, and has some of the characteristics of
the porphyritic gneiss. West of the same road, the mountain ridge be-
tween it and the railroad is protogene gneiss. It is also the rock of the
railroad cut at Warren summit. From the western slope of Moosilauke
the common gneiss extends southward, and there is an outcrop at the
saw-mill on Baker's river, near J. P. Boynton's, and near Dr. D. C.
French's ; also, at the saw-mill below. At both saw-mills the water has
worn deep channels in the rock.

Above Warren village, at S. Flanders's, we find common gneiss ; and

478 STRATIGRAPHICAL GEOLOGY.

north, near A. Whitcher's, the rock is fine-grained, and the stratification
is remarkably distinct, A mile and a quarter north, on a road west, near
J. Whitcher's, is a thick-bedded, very light-colored gneiss ; and south,
near N. Libby's, there is hornblende gneiss. West of the railroad,
beginning at Webster Slide mountain and extending west to the Cross
iron-ore mine in Piermont, and south-west to Ore hill, the rock is a
fine-grained gneiss, sometimes forming a transition state into mica
schist, — and everywhere it is more or less ferruginous. A band of this
rock extends southward into Wentworth. Gneiss is found between Ore
hill and Tarleton pond, and there is an outcrop near J. H. Kelley's ; that
on the road west of Ore hill may be more allied to the Bethlehem than
the common gneiss. At Warren village we find common gneiss ; and on
Hurricane brook there is the same coarse variety as at the saw-mills on
Baker's river. The fine-grained gneiss and quartzite west are the min-
eral-bearing rocks of this section of the state.

In Wentworth a very large proportion of the rocks is common gneiss ;
but we have besides a fibrolite schist on the ridge of Mt. Carr, which
crosses the north-east corner of the town; a mica schist, which runs to
the north from near N. Coolidge's and outcrops at the outlet of Lower
Baker pond ; and west of the mica schist, at T. Simpson's, we have the
Bethlehem gneiss. The last two disappear a mile and a half south of
Simpson's; and the common gneiss extends entirely across the south
part of the town. On the south-east, it extends beyond the border of
Wentworth into Rumney. A fine-grained gneiss outcrops at E. Cur-
rier's ; and west of this we have fibrolite schists. On the west, the com-
mon gneiss extends into Orford a fourth of a mile west of E. Lamprey's.

In Dorchester the prevailing rock is also common gneiss. Its western
boundary runs from near E. Lamprey's in Orford to a point just west of
McCutchins pond, thence to Norris pond and to the west of its outlet,
and thence it probably runs to the south line of Dorchester, near Clark's
pond. In the north-west corner of the town it has on the west quartzite
and the chloritic hornblende schists of Smart's mountain; at J. Clough's,
a hornblende rock and a fine-grained gneiss or mica schist ; and south of
the outlet of Norris pond, the friable, brittle rock that resembles pro-
togenc gneiss. On the cast we have only the fibrolite schist. It runs
along in the edge of Groton, crosses over into Dorchester a mile north

GEOLOGY OF THE MERRIMACK DISTRICT. 479

of the Stream near Mrs. R. P. Holt's, then runs south nearly parallel with
the line of Groton, and strikes the corner of Orange. Included within
these lines common gneiss is the only rock, except a feldspar porphyry
on the new road east of Norris pond, and a breccia, with porphyry, on
the east side of Pollard hill. The dip of the strata here, as in Went-
worth, is easterly.

The gneiss of Canaan has not that uniformity of texture that we find
in the gneiss of Dorchester and Wentworth. While the protogene gneiss
in the west part of Canaan is coarser than that northward, the other
gneisses become finer-grained and more variable in texture ; besides, we
have hornblende schist that appears, in some instances, to be interstrati-
fied with the gneiss. Sometimes these hornblende bands are continuous
for some distance. One is seen on Indian river, near East Canaan, con-
tinuing west, parallel with the railroad. It turns north, extends along the
west side of the Pinnacle, and northward, crossing the road near J. P.
Barber's. That which outcrops near R. Hayward's is probably a con-
tinuation of this, and possibly that at R. Atwell's ; — at least, we find that
the coarse gneiss which we have in Dorchester and northward, is east of
the line of the outcrop of this hornblende schist, and that the rocks
intervening between it and the protogene gneiss are generally fine-grained
granitic gneisses, and probably form the upper division of the Bethlehem
group. These rocks extend south, and occupy a large part of Enfield ;
for directly south from Canaan the Bethlehem gneiss disappears, and it is
only in the extreme east part of Enfield that the common or Lake gneiss
is found. These fine-grained granitic gneisses in the north part of Gran-
tham are replaced by the Lake gneiss. It is difficult to tell anything
about the stratigraphical relations of this granitic gneiss, since the ar-
rangement of the constituents of the rock gives little or no indication of
stratification. In Canaan, on the west, we have the Bethlehem gneiss ;
but south, in Enfield, we have argillaceous schists, mica schists, and
quartzites. The line that separates the schists from the granitic gneiss
runs — from a point half or three quarters of a mile east of the north-
west corner of the town — south-east; but after it passes Lily ponds it
turns a little to the west, then suddenly to the east, and forms a curve
around the Lake gneiss in the north part of Grantham. As a whole, this
area of granitic gneiss is oblong. It is about twelve miles in length, and

480 STRATIGRAPHICAL GEOLOGY.

has its greatest width in Enfield, where it is about five miles wide. In
Canaan, however, west of Hart's pond, it is not more than two and a
quarter miles wide.

Confining the Lake gneiss to the gneiss of a coarse granular texture,
it is narrow in the north part of Canaan, but to the south it becomes
wider, and opposite Hart's pond it extends into Orange. South of East
Canaan it contracts again, and nearly the whole is crowded into the
south-west corner of Orange. The rock at Orange summit is a coarse
granular gneiss; and though there are occasionally feldspar crystals, yet
the amount of feldspar in the rocks as a whole seems to be much less
than is usual in the Lake gneiss. Following this rock, on the east, every-
where in Orange we have fibrolite schist. The common gneiss extends
along the entire western part of Grafton. It has quite a uniform texture,
and is a mile in width along the northern border, and two miles in width
on the line of Springfield. Typical varieties of this rock are found, par-
ticularly in the vicinity of Grafton pond. It does not extend far into
Enfield ; but near the south-eastern corner of the town the northern and
western boundary turns to the west along the line of Enfield and Gran-
tham. It outcrops in Grantham east of the Butternut pond, where it is
coarse and granular. To the south-west, it can be seen on Grass Pond
brook, near G. Colburn's. These outcrops are near its north-western
limit ; and from near Colburn's the western boundary of the gneiss ex-
tends along the east side of Sugar hill, thence southward along the east
base of Croydon mountain. East of this line, except the protogene
gneiss and quartz, the common gneiss is the only rock in the town. We
have not yet determined the exact eastern limit of this rock in Spring-
field. The rock in many places has feldspar crystals scattered through
it, which sometimes make it difficult to distinguish it from the porphy-
ritic gneiss to the east; though where the rock has been examined its
foliated texture is always more marked in the gneiss of the west part of
Springfield than in the porphyritic. In Sunapee, along through the west
part of the town, we find the typical Lake gneiss, and on the west we
have the White Mountain schists and gneisses. There are many out-
crops of the common gneiss on the road west and south of Ledge pond,
on Young's hill, to the south of Sugar river, and in the hill south of H.
Crowcll's, near Union church. The strata have an easterly dip, and the

GEOLOGY OF THE MERRIMACK DISTRICT. 48 1

inclination is much less than that of the rocks farther north. In the
north part of the town the inclination is 15°, but it increases southward,
and near G. B. Wilson's it is 45°.

In Croydon, except the mountain range on the west, and the protogene
gneiss and the quartz, all the rocks are the common or Lake gneiss. In
the south-east corner of the town the inclination of the strata is less
even than in Sunapee ; but we have here what is not common in this
gneiss, namely, coarse granite veins. There is one south-west of J. Ry-
der's ; and near H. Clark's there is one where the crystals of mica are
two inches across. Near Rock Bound pond the common gneiss has a
westerly dip — a thing quite rare. There is quite an area west of Croydon
branch, where the gneiss resembles the protogene more than the common
gneiss ; but west of this, as near W. Stockwell's, the common gneiss has
an easterly dip of 20°. Along the road from Croydon Flat to Brighton,
the strata seem to be horizontal, though the jointing may have made the
stratification obscure. The gneiss extends southward, and occupies the
whole of the town of Newport, except a strip about two miles wide along
the western border. The line separating the gneiss from the schists and
the quartzites is very direct ; it crosses the road near N. Gould's, east of
D. C. Story's, near T. M. Cutting's, east of Mt. Tug, and between L. P.
Tenney's and S. Wright'.3. The common gneiss is found on the high
hills in the east part of the town, and specimens were obtained between
Newport village and Kelleyville and near A. D. Pike's. We found here,
as in Sunapee, that the inclination of the strata is nowhere very great.
There is a large amount of drift along the Goshen branch and moraines
east of school-house No. 12. In Goshen, there are prominent outcrops of
the common gneiss, on the stream north of Mill Village, on Dodge hill,
east of the Goshen branch, and at the Four Corners. From Chandler
hill, northward, there is a fine-grained rock, which, in some places, is pyr-
itiferous; and south of A. D. Bartlett's there is granitic gneiss. This
small area belongs to the Montalban series, and is an outlier from, or con-
nected with, that in Sunapee.

In Unity, the common or Lake gneiss is found in the entire east part
of the town, and extends west nearly to Unity Centre. The line that
separates the gneiss from the schists and quartzites extends southward
from Newport, and crosses the road near S. Pierce's, just west of S.

VOL. II. 61

482 STRATIGRAPHICAL GEOLOGY.

Messenger's. We then follow it southward, near J. Kimball's and west
of Cold pond. The rocks have everywhere an easterly dip. They vary
somewhat in strike, but are quite uniform, generally running north and
south, and have the coarse granular texture of the common gneiss. In
the gneiss near E. Cutting's there is a coarse granite vein ; and we also
have a quartz schist associated with the gneiss at the forks of the road
near S. Walker's. The band crosses the road near J. G. Smith's. It is
quite uncommon to find the quartz schist running across the gneiss, as
here, and it shows clearly its unconformability with the gneiss, and its
more recent origin. Going eastward from A. C. Sleeper's, we have (i)
mica schist, with a dip of S. 50° E. 15°; (2) a quartzite, with a dip of S.
70° E. 20°; (3) a mica schist, with staurolite, dipping S. 20° E. 20°; (4)
gneiss, with a dip of S. 30° E. 20°, — showing not only that the schist
and quartzite have been inverted, but that the gneiss has been pushed
over them. The common gneiss extends southward from Unity and
Goshen into Acworth and Lempster. It occupies a strip a mile and a
half to two miles in width in the east part of Acworth. A line bounding
it on the west extends south from a point west of Cold pond, around the
west base of Coffin hill. It crosses the road near J. Davis's, and runs
near Mitchell pond and school-house No. 7. Keeping east of the road
across Grant hill, it crosses Cold river near Wyman's saw-mill, and con-
tinues southward around the west side of Gates mountain. In Lempster,
it occupies the whole of the north part of the town, but it keeps to the
west of Lempster mountain. In the south-east corner of the town we
find the schist and gneisses of Lempster mountain, and the porphyritic
gneiss to the south-east of these. The common gneiss sends out an out-
lier on the road near William Gee's ; but the schist is found on the road
by Beaver pond ; so we have a very narrow strip of gneiss, if any, in the
extreme south-west corner of the town.

South of Acworth and Lempster this great band of common gneiss,
which we have followed southward from Landaff, loses, in a great meas-
ure, its well defined limits. As the isolated area of gneiss that extends
from the Connecticut to the north-west part of Alstead, and which has
been described upon page 410, passes into the micaceous gneiss of the
White Mountain series on the south, so here, as we go southward from
the northern boundary of Alstead and Marlow, the character of the rock,

GEOLOGY DF THE MERRIMACK DISTRICT. 483

as the common gneiss, except in a few small areas, is almost obliterated,
and in its place we have micaceous and hornblende gneisses ; and at the
same time the fibrolite schist assumes more the character of a well de-
fined gneiss. When it is known that these rocks have again their char-
acteristic forms, in Surry, it leaves little doubt that all these rocks — the
common, the hornblende, the micaceous, and the fibrolite gneisses, in-
cluding the fibrolite schist — belong to one great series. From near L.
Honey's in Acworth the common gneiss extends into Marlow, and its
southern boundary is probably just below Trout pond. Near H. Priest's
we again find the common gneiss ; but as we go northward we have mica
schist, at C. W. George's in Acworth. The rock has the character of a
fine-grained gneiss at G. H. Gassett's. At J. Buckminster's and S. E.
Mann's we have mica schist. Frequently in this vicinity we find bands
of hornblende schist. In the north-east corner of Alstead, near J. H,
Shepherd's, we have a fine-grained gneiss again. Going towards Mar-
low, and turning north by the cemetery, we find bands of hornblende
schist; but between the cemetery and Gustin pond is the boundary be-
tween these rocks and the fibrolite gneiss. At the forks of the road, east
of A. Mack's, and in Alstead, at A. Kent's, we have mica schist, the dip
being easterly, and nearly the same at both places. We have mica schist,
also, north, near Mrs. Whitcomb's ; and in the coarse granite veins here
there have been several openings made for mica. In the vicinity of Warren
pond we have common gneiss. An outcrop at J. Caldwell's, south-west
of the pond, has an easterly dip, and it seems to pass into a mica schist.
In the northern part of the town, on the south-east side of Cobb's hill,
there is a fine-grained gneiss, which has generally a westerly dip, though
the strata are often curved, so that in places they are inverted. One out-
crop, where it runs into the hill, looks like a section of a cone ; and here
we have schists on both sides of the gneiss. This has been noticed in a
preceding chapter.

South-east, near the road up Warren brook, between J. P. Forrestall's
and L. Way's, there is gneiss again with an easterly dip, and about a mile
above Way's there is mica schist. South-west, at Mrs. Emerson's, on the
road north of Alstead centre, the rock is a quartzose mica schist, and the
dip is exceedingly variable. On the road south-west from the centre, we
have mica schist to the line of Walpole, except at George Pratt's, where

484 STRATIGRAPHICAL GEOLOGY.

there is a gneiss rich in quartz. South, at J. H. Moriarty's, there is
gneiss also rich in quartz, and a dark arenaceous schist. From this point
south-east, on the road to Surry as far south as R. E, Smith's, and also
in the road east from E. Slade's, the schists are like those of the Coos
group. But fifty rods north-west of T. A. Bolster's, there is a greenish
quartzose rock in which there is hornblende ; this is interstratified with
a dark gray gneiss and pyritiferous schist. On the road south from
Bolster's, we have the wrinkled argillaceous mica schists of the Coos
group. In the south part of Alstead, on the Surry and Alstead road, we
have a wrinkled and contorted mica schist. Just below Robbins's there
is a broad band of coarse granite, mostly feldspar ; and on both sides of
this there is a mica schist, common elsewhere in Alstead. At a turn in
the road, three quarters of a mile north of Robbins's, there is gneiss rich
in quartz, and above this mica schist. At the forks of the road near E.
H. Flint's, there is hornblende schist ; but east, to J. B. Cady's, we have
gneiss ; north from Alstead centre to Ellis's there is also gneiss, and east
of these two points there is mica schist ; but with this, at J. Blood's, there
is hornblende schist. As we go southward, on the road from Blood's, we
come to the micaceous gneiss of the White Mountain series, and there is
a well-marked outcrop near the southern border of the town, at J. N.
Hodgkin's. On a road farther east, that runs south from Warren pond,
we have, at D. W. Sawyer's, a micaceous gneiss of fine foliated texture,
forming a transition state into mica schist, — and this is the character of
the rock south to the line of Gilsum. Near J. A. Kidder's it contains
coarse granitic veins that have been worked for mica ; and there has been
a small excavation by the side of the road at Gleason's. A quarter of a
mile west of S. Goodhue's, mica has been quarried at intervals for many
years, and the rock is in places a genuine gneiss, and frequently contains
fibrolite. Along the top of a ridge there is an immense coarse granitic
vein, in parts of which there are masses of glassy, translucent quartz.
On the road north-east from Gleason's the rock is generally a micaceous
gneiss. At D. Knight's, there is an opening that has been made for
mica ; also, one at H. R. Knight's. On the road the rock is more like
mica schist, contains garnets, and is often pyritiferous. North-west of
the house there is a coarse granitic vein, and then the rock resembles
the gneiss of Marlow, which will be described under the division of

GEOLOGY OF THE MERRIMACK DISTRICT. 485

pyritiferous schists. At A. Whittemore's, in Marlow, west of Grassy brook,
we have a fine-grained gneiss. On this road, from the Hne of Marlow to the
village, the micaceous gneiss was not seen. As we go south from the
west part of Alstead into Surry, the rocks have a more definite character,
although the typical variety of the common gneiss has not been seen in
any extended outcrop. There is gneiss east and south-east of the village.
Even here the rocks are more allied to the protogene than the common
gneiss, and they are probably varieties of it. We find gneiss on the road
to Mine ledge, and on the road south it can be seen at E. Woodward's ;
from thence to Keene there are no ledges of any kind ; neither are there
any ledges on the direct road from Surry to Keene. As there is some
doubt whether there is any outcrop of the typical variety of the com-
mon gneiss in Keene, the rock is described under protogene gneiss,
which is the prevailing rock. In the central and south-east part of West-
moreland we have a gneiss that is, at least, closely allied to that in the
northern part of this district, and northward. Specimens of the reddish
variety of protogene gneiss from Surry and Keene can hardly be distin-
guished from some specimens of the gneiss obtained in Jefferson, near
the Mt. Adams house.

The northern and western limit of the gneiss, including the protogene,
is as follows : A line drawn from a point just north of school-house No.
4, in Surry, to the tannery north-west of Westmoreland village, would
represent the boundary on the north-west. This, continued to the south-
west nearly to the molybdenite mine, then sweeping round into the edge
of Chesterfield, just north of L. Pierce's, would represent it on the west ; —
the line then extends to the north part of Spofford pond, crossing it, and
runs south of A. Chandler's ; then round to Factory village, crossing the
outlet of the lake, striking the stream again by the lower mill, crossing the
road near E. R. Wellington's, and turning southward to the forks of the
road east of school-house No. 14: this represents its south-western bound-
ary. South of the east part of this line, between the gneiss and the por-
phyritic gneiss, we have an oval area of mica schists, quartzites, and
conglomerates. The area in the east part of Westmoreland is noticed
under protogene gneiss. The gneiss outcrops at the harness shop
near D. Warren's, on the top and east side of the hill west of Mrs. Car-
lisle's, at J. L. Paine's, at O. Leonard's, and J. Briggs's, Jr. South of the

486 STRATIGRAPHICAL GEOLOGY.

village, at the Curtis mine, and as far south as Spofford lake, south-east
at E. Pierce's and Jas. Corastock's, south-west of Comstock's nearly to
Factoryville, and along the east side of Pistareen mountain, there are
many ledges. At the south end of the mountain the rock appears to be
intrusive, and is composed largely of feldspar. South of Spofford lake
there is a slaty gneiss, unlike anything found elsewhere, unless there is a
small area north of the Barker place in Westmoreland, and west of Mine
ledge in Surry. It is cut by numerous cleavage planes, and dips to the
south. Nowhere is the hornblende gneiss so persistent as in Westmore-
land, but it is associated with the mica schist rather than with the com-
mon gneiss, and quartzite is also found in many places. The succession
of the rocks here is as follows : Gneiss is everywhere the underlying
rock ; hornblende schist follows the gneiss, and mica schist the horn-
blende. At Westmoreland, however, as shown in Fig. y?>, there is a
quartzite or quartz between the gneiss and the hornblende schist.

Between the area of gneiss in Surry and Westmoreland and that in
Swanzey, where gneiss occurs, it is of the protogene variety, and in Surry
and southward to the state line the gneiss is a well defined variety of the
Bethlehem gneiss. It appears on Mt, Caesar, in the Ashuelot mountains,
on the line of Swanzey and Winchester, on Attleboro' and Second moun-
tains in Richmond, and in the south-east part of Winchester. In the
north-east part of Swanzey the rocks are for the most part concealed by
drift. Going west from Marlborough depot into Swanzey, near A, T.
Lane's, is a gneiss that has some of the characteristics of the common va-
riety, and it contains a coarse granite vein that carries magnetite. Some
of the crystals are an inch in thickness. On Mt. Caesar the strata seem
to dip westerly io°, though generally the strata of this rock are nearly
vertical. North, at L. Dickenson's, the gneiss is more micaceous than
elsewhere ; and the dip is about the same as on Mt. Caesar. Northward,
to the town line, there is drift, generally a fine gravel. Southward, at
Unionville, there is gneiss ; and in the south-east corner of the town, and
in the edge of Troy, there is a granite composed largely of quartz. East
of Swanzey pond, near L. W. Darling's, there arc extensive outcrops of
gneiss ; and in the extreme south-west corner of the town, between Win-
chester and Richmond, the rock is altogether gneiss. On the north-west
side of Franklin mountain it has been quarried to some extent, and a

GEOLOGY OF THE MERRIMACK DISTRICT. 487

very desirable stone is obtained. It was used in the construction of the
Episcopal church at Keene.

On a road, now discontinued, south of Franklin mountain, there are
several outcrops of gneiss ; and a boulder was seen, containing iron ore,
evidently from this rock. At R. Weeks's, on the road south from school-
house No. 8 in Swanzey, the rock may be intrusive. Where this road
enters Winchester, at Naramore's mill, there is an interesting outcrop of
gneiss. The strata are nearly vertical, and dark bands are very distinct.
The mineral giving these bands their dark color is probably hornblende,
though there may be some tourmaline present. To the south-west, near
W. Hartwell's, these dark bands are also found. South-east, on the road
to Richmond, at B. Corliss's, and from school-house No. 3 to Sandy pond,
the rock is chiefly granite, but occasionally there are dark gneissic bands.
In Winchester, on the western slope of Second mountain, there is gneiss
nearly vertical, but dipping westerly. On the north-west side of Stone
mountain there are many outcrops with dark bands, as at Naramore's
mill, and this rock extends south to Peaked hill, where the strata are
vertical. Going west from the summit of Peaked hill, we have a mica-
ceous gneiss, and this extends northward along the west slope of Stone
mountain, two thirds of the way from the summit to the base. In this
rock, on Stone mountain, there is quite an extensive vein of rhodonite.
The locality can be discovered after finding a depression that in the spring
is filled with water ; — it is about five rods north-west of this depression.
West of this micaceous gneiss, on the ridge of Peaked hill, we have a
pyritiferous schist with an easterly dip, and in this are coarse granite veins.
Near the road is a hornblende schist, the dip of which is variable. East of
the micaceous gneiss of Stone mountain we have a fine-grained gneiss. It
outcrops just north of the cemetery; and where it is seen between the
cemetery and the village it contains a coarse granite vein. On the road
south-east from William Follett's, gneiss is the prevailing rock; but on
a road, now discontinued, south-west of Follett's, we have hornblende
gneiss. This contains an iron ore, which was worked to a limited extent
many years ago.

STRATIGRAPHICAL GEOLOGY.

Gneiss. Dip of the Strata.

Landaff and East on.

At J. T. Gale's, N. 70° E. 20°.

West of J. Clough's, N. 40° W. 50°.

Dark fine-grained gneiss, a mile north of
iron mine, N. 60° W. 50°.

At iron mine, N. 80°.

Fine-grained gneiss, N. 34° W. 45°.

I mile west of D. N. Page's, N. 62° W. 70°.

West of Iron Ore hill, N, 30° W.

Fine-grained gneiss west of last, N. 40°
W. 68°.

Besides several of these localities there are
specimens in the cabinet from near E.
E. Merrill's, J. McConnell's, W. L.
Shattuck's, a mile above Dansville, —
the last especially represents the com-
mon gneiss.

Benton.

East of D. Howe's, S. 80° W. 60°.

At saw-mill. Tunnel brook, N. 46° E. 40°.

Height of land, N. 70° E. 65°.

The strata dip easterly, also, along the
section on the western slope of Moos-
ilauke.

Warren.

At R. B. French's saw-mill, S. 30° E. 70°.

Up Hurricane brook, a mile above Clif-
ford's, S. 50° E. 62°.
IVentworth.

Between J. L. Ellsworth's and Rocky
pond, S. 22° E. 58°.

At S. Ellsworth's, S. 52° E. 50°.

Near W. Evans's, S. 82° E. 50°.

The specimens in the cabinet which are
on the section that passes through
Wentworth represent well the rocks
of the town.

Dorchester.

\\ miles N. W. of W. Robbins's, S. 70°
E. 64°.

Near McCutchins pond, S. 62° E. 55°.

At J. Cogswell's, S. 82° E. 35°.

At town-house, S. 55° E. 20°.

At A. Blodgett's saw-mill, S. 30° E. 25°.

At J. Blaisdell's, S. 53° E. 65°.

Outlet of Norris pond, N. 75° E. 60°.
Canaaii and Orange.

Protogene gneiss, h. mile up Martin Mead-
ow brook, S. 32° E. 40°.

At brick school-house, S. 56° E. 20°.

At S. Towle's, N. 32° E. 25°.

Fine-grained gneiss between school-house
and Goose pond, N. 32° E. 25°.

At C. Bartlett's, N. 63° E. 20°.

Coarse granular gneiss, R. C. Ladd's, S
82° E. 32°.

Enfield and Grafton.

At D. Goodrich's, N. 82° E. 62°.

Line of Enfield and Grantham, W. 76°.

East side of East hill, N. 80^ E. 46°.

Near M. S. Choate's, S. 53° E. 62°.

At W. C. Buffum's, N. 80° E. 30°.
Gratttham.

At C. Colburn's, S. 43° E. 45°-

At O. B. Buswell's, S. 18° E. 25°.

East of Butternut pond, S. 78° W. 70°.

Croydon.
Rock Bound pond, S. 62° W. 15°.
At W. Stockwell's, S. 58° E. 20°.

Siaiapee.
At S. Dodge's, S. 70° E. 50°.
At Charles George's, S. 68° E. 25°.
Near H. Crowell's, N. 82° E. 60°.
At G. B. Wilson's, S. 50° E. 45°.

Newport.
Near H. E. Hanson's, S. 12° W. 10°.
At Henry A. Jenks's, S. 10° W. 18°.
Near T. Scranton's, W. 12°.
At A. D. Pike's, S. 56° E. 10°.

GEOLOGY OF THE MERRIMACK DISTRICT.

489

At L. P. Tenney's, N. 82° E. 20°.

The massive character of the rock in some

of the localities in Newport makes the

dip of the strata very obscure.
Unity.
At N. C. Himtoon's, N. 80° E. 10°.
At S. Pierce's, N. 82° E. 15°.
East of A. C. Sleeper's, S. 38° E. 18°.

Acivorth.
South of Coffin hill, S. 18° E. 15°.
At S. McKeen's, S. 53° E. 68°.
Forks of road east of school-house No. 10,

S. 68° E. 15°.

Leinpster.
At J. Carpenter's, S. 53° E. 15°.
At T. Pollard's, S. 68° E. 18°.
At Wm. Gee's, N. 38° E. 70°.

Marloiv.
At L. S. Rogers's, N. 82° E. 48°.
At H. Priest's, S. 48° E. 25°.
Fork of road east of A. Mack's, S, 32° E.

60°.
East of village, S. 58° E. 80°.
At A. Whittemore's, S. 56° E. 50°.

Stoddard.

At C. D. Elliott's, S. 62° E. 88°.
Keene and Westmoreland.

South of reservoir, S. 70° E. 40°.

The protogene gneiss in the east j^art of
Keene seems to have an easterly dip ;
but here and in Westmoreland, the
dip is very obscure.
Swajizey.

The gneiss of Swanzey appears to be gen-
erally vertical, though there seem to
be two exceptions, one on Mt. Caesar,
and the other at L. Dickenson's. At
both places the inclination is 10° or
12° north-westerly.

Winchester.
At Naramore's mill the strata are vertical.
West slope of Second mountain, S. 82°

W. 75°-
North-west of E. S. Adams', N. 82° E. 80°.
West base of Stone mountain, S. 70° E.

58°.
Peaked hill, strata vertical ; strike N. 10°

W.

Ferruginous Schists.
These schists are scarcely distinguishable, on the one hand, from
the White Mountain schists and gneisses, and, on the other, from the
fibrolite schists. So nearly allied are some of these rocks to the White
Mountain schists, in many of their lithological characteristics, that
they seem to pass, by insensible gradations, into rocks so like those
that occur in the White Mountain region, that there seems to be little
doubt but that all of the rocks we shall describe under the head of
"Ferruginous Schists" belong to the White Mountain series. Neither
is there any very marked distinction, save the presence of fibrolite, be-
tween these rocks and those we shall describe under the head of "Fibro-
lite Schists." In these ferruginous schists the large plates of mica are
usually, though not always, wanting. They often contain beds of graph-
ite, and are sometimes concretionary. The relations to the porphyritic
gneiss show them to be among the oldest of our crystalline schists. The
VOL. II. 62

490 STRATIGRAPHICAL GEOLOGY.

most northern outcrop where this rock is seen is on Mt. Prospect, in
Holderness, and here it is associated with a porphyritic rock, which in
some respects is unhke the porphyritic gneiss found elsewhere. It
extends southward, and is the rock at Ashland village ; also of Squam
mountain to the east.

On the road north of Little Squam lake, near the town-house, we have
the ferruginous schist, and with it the characteristic porphyritic gneiss ;
while south, on the road to Center Harbor, particularly at Mrs. T.
Shepard's, we have distinct White Mountain gneiss. Elsewhere along
this road, northward, the rock frequently contains mica, and is de-
cidedly ferruginous, showing plainly that the ferruginous schist and the
White Mountain schists belong to the same series of rocks. We have
the same change in the rock, though not so marked, going west from Ply-
mouth. South, through Bridgewater, the rocks are uniformly pyritif-
erous. If this is the same rock as the fibrolite schist or gneiss, then we
have a line of outcrops from Mt. Prospect to the southern border of the
state, including Ragged, Kearsarge, and Monadnock mountains. In the
town of Goshen, east of L. Baker's, we have porphyritic gneiss, and with
it there is White Mountain gneiss. East of this is the pyritiferous schist,
which here contains graphite. North-west of Washington Centre there
are outcrops of this siliceous pyritiferous schist; but it is in Cheshire
county where these schists are most extensively developed. They occupy
a large part of Sullivan, Nelson, Roxbury, Harrisville, Dublin, and
Rindge, also parts of Marlborough, Jaffrey, Fitzwilliam, and Richmond.
In Marlow there is a gneissic rock that does not come under either
of the heads we have mentioned, and it may form a transition state
into mica schist. There are boulders of it at the village, and an out-
crop just east, where it is a fine-grained gneiss, and contains a gray
fibrolite that has a fibro-lamellar texture. A mile below the village, and
east of the road, there are many outcrops of gneiss. Here it contains
nodular masses of quartz, from half an inch to three or four inches in
diameter; and sometimes it contains amorphous masses of feldspar from
half an inch to two inches in diameter. Elsewhere we find the crystals
of the common varieties of porphyritic gneiss. Through the west part
of Stoddard the rock is gneiss, and is exceedingly variable. On Stoddard
heights it resembles a micaceous gneiss. Along the Ashuelot in Gilsum,

GEOLOGY OF THE MERRIMACK DISTRICT. 49I

as far south as the village, the outcrop examined was a coarse granite.
In Sullivan, at Bear Den mountain on the west, and from near D. Sew-
ard's, at least as far as Moore's mill in Stoddard, the rocks resemble very
closely the White Mountain gneisses. Between these points the rocks
are generally highly siliceous and pyritiferous. Where the rocks are not
ferruginous, as east of D. Seward's, the strata are often twisted into nod-
ular-like masses. South-east of the church, on the road to East Sullivan,
near Weathron & Cordney's, there is a coarse granite vein containing
beryl. In Nelson the rocks are uniformly pyritiferous, except in the ex-
treme eastern part of the town. In the north-east part of the town, at
H. Wilson's, there is a bed included in the porphyritic gneiss. At A.
Robbins's we find nodular concretions in the schist, which is here graph-
itic, and contains bright almandine garnets. In the vicinity of the Sea-
bury graphite mine, the rocks are decidedly pyritiferous. Near the town
farm, where large quantities of graphite have been obtained, the rocks
are of the same character. At Page's, to the west, the cleavage is more
marked than elsewhere in the town. Near Noah W. Hardy's the rock is
generally the common pyritiferous schist, though there are bands that
resemble gneiss.

In the entire eastern part of Roxbury we find that the rocks are ferru-
ginous, and probably extend as far west as G. Nims's, on the road from
the church to Keene. In the south part of the town they extend half a
mile west of the forks of the road south of Horse hill. West of these
rocks we have the White Mountain gneisses. In Roxbury, the ferrugi-
nous schist abounds in concretions. They are much more frequent than
in this rock elsewhere, and they lie in all directions, with regard to the
strata, sometimes directly across them. They are of various sizes and
shapes. One was seen three feet in length, and not more than three
inches in thickness. Usually they look like rounded pebbles, which some
have thought them to be; but a fragment, two feet in length and not
more than two inches in thickness, would hardly lie at right angles to
the stratification of the rock, or even diagonally across the strata. The
shape of some are peculiar, being thick at one end and tapering almost
to a point at the other. This shows, also, that they can hardly be peb-
bles or boulders. Near the church, at the centre of the town, and on the
south-west side of Horse hill, a person can have a fine opportunity for

492 STRATIGRAPHICAL GEOLOGY.

studying these forms. The Pinnacle, north-west of the church, is topped
out with a coarse granite containing graphic granite and plumose mica.
On the south of the Pinnacle and on Bassett hill we have the rock com-
mon to this part of the town. In the west part of the town the ferrugi-
nous schist appears to verge into the schists and gneisses of the White
Mountain series ; at least, there is no well-marked line of demarcation be-
tween them, except when we come to granitic gneiss, which is not found
with the former. In Marlborough, except for a short distance on the
road south-west of Cummings pond, the gneiss on the road west of Stone
pond, and in the south-east part of the town, the rocks are either fibro-
lite schists or White Mountain gneisses. In the west part of Harrisville
the rocks are nearly everywhere pyritiferous. At West Harrisville the
cleavage is more distinct than is common in this rock. A mile to the
east, where the rock is more gneissic, the strata are bent and contorted, —
something not very common in this section. There is a small area of
dark gneiss near the outlet of Breed pond. On the road from West Har-
risville, and at James Derby's, the rock is also gneissic. To the east, at
John Yadley's, the rock is very much jointed and decidedly ferruginous;
but east, near S. Follett's, and on the hill south, near J. White's, the rock
is less ferruginous, and has somewhat the character of hydro-mica schist.
At Harrisville village the rock is gneissic, and resembles somewhat that
in Marlborough village. A line drawn from near the outlet of Long
pond to the inlet of North pond, and extended southward to the east
end of Monadnock lake, would show the eastern limit of the ferruginous
schist.

In Dublin, near P. Morse's, and north-west, we have the ferruginous
concretionary schist. On a farm road running south from the road west
of Thomas Fisk's, the concretions are numerous and distinct. These
schists extend north-west, probably, to the line of Marlborough ; but on the
road south from J, Morse's to Marlborough the rock has more the character
of gneiss. Near S. P. Frost's, at school-house No. 3, there are numerous
ledges. Just north of Thorndike pond, in the south part of the town, is
the only other locality where there are characteristic rocks of the ferru-
ginous and concretionary schists. Most of the rocks in Dublin, includ-
ing Beech hill, the great ridge of Monadnock, and quite an area to the
south-east of the village, differ quite widely from these, and will be

GEOLOGY O'^ THE MERRIMACK DISTRICT. 493

described under the head of fibroHte schists. In Jaffrey, except the
north-west part, some outcrops on the road west of Jaffrey village, and two
areas of porphyritic gneiss, the rocks are generally pyritiferous schists,
and mostly without concretions. On the road to Mt. Monadnock, for
some distance above the gate, we find pyritiferous schist ; but east, on
the road to Jaffrey village, there are several kinds of rock. Near the
height of land there is a granitic gneiss quite uniform in texture ; then
we have a common gneiss with crystals of feldspar ; this is followed by a
highly contorted mica schist near an old mill ; then we have the concre-
tionary ferruginous schist ; and between this and the village, the gneiss
with crystals of feldspar. Three miles north of Jaffrey village, on the
road to Dublin, there is gneiss with small feldspar crystals, and for a mile
north-east we find pyritiferous schist ; also on the road east of Thorndike
pond. South-west of Jaffrey village, between J. Priest's and J. Spauld-
ing's, we find gneiss ; and then, except the porphyritic gneiss near A.
Emery's, we have only drift to East Jaffrey, and there are no outcrops of
rock on the road towards West Rindge. Following down the Contoo-
cook, we find ledges of pyritiferous schist near the town line. On both
of the roads running south-east from East Jaffrey we find nothing but
drift, until we get nearly to Prescottville (Squantum). About half a mile
north-west of school-house No. i, there is a band of gneiss quite free
from iron with the ferruginous schist ; near Capt. E. Prescott's there is a
band of coarse granite, — and the schist here, although decidedly pyritifer-
ous, has the mica of the White Mountain gneisses. The rock at the village
and at S. Rolfe's, half a mile west, is very much discolored with iron.

The rocks in Rindge are more uniform than in any other town in
Cheshire county. The town is, however, largely covered by drift, which,
in this southern section of the state, is quite different from that north-
ward. In Rindge, particularly, boulders of large size are seldom found ;
the drift occurs in rounded hills, which are composed largely of gravel
and pebbles. From the town line, on the road from Fitzwilliam, there
are no ledges until we get near West Rindge (Blakeville). Fifty rods
to the west of the station, the rock is a decomposing, foliated pyritiferous
gneiss ; and east, at a brook, there is a coarse granite vein. Going towards
Rindge, near C. K. Stickney's, the rock resembles that west of the station,
and here there is a coarse granite vein. Near the village there are many

494 STRATIGRAPHICAL GEOLOGY.

ledges ; they are everywhere pyritiferous, and in places they resemble
the White Mountain schists. South-east of Rindge, on the road by F.
Wilder's, there is only drift to Monomonac lake. North of the east arm
of the lake there is an outcrop of schist, but the rock here is mostly
an intrusive quartzose granite. South-east of J. R. Bixby's we have a
ferruginous schist, and also coarse granite veins ; at A. Griswold's
there is a coarse granite, and then drift south-east to the state line.
At East Rindge there are many outcrops of pyritiferous schist, and north
it can be seen near A. Giles's ; also at school-house No. 7, with granitic
veins. On the road to New Ipswich, at J. F. Hale's, there is a fine-
grained gneiss ; and a quarter of a mile east, south of the road, the strata
are twisted and contorted. At S. J. Hardison's, and east to the town
line, where the ferruginous schist appears, the dip is generally easterly,
though the inclination is quite variable. Along the road north of Hub-
bard pond, nearly to L. P. Towne's, the drift is sand. The outcrops of
rock on the road from Grassy pond to Rindge are ferruginous schist.
The north part of the town is mainly drift, but there is a ledge near F.
Gardner's. Between Rindge and the south-west corner of the town, the
rocks, although somewhat ferruginous, are closely allied in many of their
lithological characteristics to the White Mountain schists and gneisses.

In Fitzwilliam, near Wm. F. Ferry's on the east, and at H. Fisher's
on the north-west, the rocks are decidedly pyritiferous ; — elsewhere in
the town we have andalusite and White Mountain schists, and porphyritic
gneisses. In Richmond, except in the north-west part of the town, we
have White Mountain schists and gneisses and pyritiferous schists ;
though here the two are hardly distinguishable from each other, and
are probably only a continuation of the White Mountain rocks of Troy.
They will be mentioned more specifically under the next head.

FiBROLiTE Schists and Gneisses.

This group of rocks consists of two bands. One is long and narrow ; it
extends from Landaff southward, and continues with some interruptions as
far as Keene ; — the other is found farther to the east, and its culminating
point is Mt. Monadnock ; from this it extends northward to Harrisville and
south-east nearly to the state line. The rock is somewhat variable, but in
Grafton county there is always a marked distinction between it and the

GEOLOGY CF THE MERRIMACK DISTRICT. 495

common gneiss on the west and the porphyritic on the east. In Sullivan
and Cheshire counties it seems sometimes to verge into the White Moun-
tain gneisses. In the south-east part of Landaff the rocks that we have
referred to in this group appear, but here they have more the character of
mica schist than gneiss. In general they are thin-bedded, and split with an
even cleavage into comparatively thin plates. Garnets are quite common,
and we find a few coarse granitic veins. The band, as a whole, seems to
have a synclinal structure ; and on the west we have hornblende schists
and common gneisses, and on the east ferruginous schists. The great
ridge running southward towards the summit of Moosilauke, between Tun-
nel brook and the great ravine west, is composed of a rock very similar to
that in Landaff; though, as we approach the summit of the mountain, the
rock has more the character of a micaceous gneiss. The old bridle path
from North Benton follows the ridge, and in many places there are
ledges, the outcrops being more numerous than on any of the other
approaches to the mountains. The whole width of the band, measured
across Moosilauke, is not far from one mile and four fifths. This is not
directly across the strata, since between the east and west summits the
strike corresponds in places very nearly with the ridge. On the west
spur of the mountain we find the rock not very unlike that on the east,
except that the cleavage planes are not so numerous, and the rock
appears to be thick-bedded and contains fibrolite. The mountain has
a synclinal structure, and the relations of the rocks to those on either
side are shown in Section VIII. The south-west side of Moosilauke is
largely covered with drift, and the micaceous gneiss and schist extend
nearly to N. Merrill's. As far as Warren is concerned, the fibrolite rocks
are found along the entire eastern border of the town. They can be seen
on the ridge east of R. K. Clement's, and there are many outcrops along
Mt. Carr. On Hurricane brook, about a mile and a quarter above R. F.
Clifford's, they succeed the common gneiss, and occupy the whole moun-
tain east. The rock here is almost massive, and is composed mainly of
quartz, mica, and fibrolite. On the ridge of Mt. Carr we begin to meet
with those great coarse granite veins so common along the entire outcrop
of this formation southward. Although the fibrolite rock has a high east-
erly dip on Mt. Carr, as we go eastward it becomes more nearly vertical,
and in Ellsworth the dip is generally westerly. It extends to Ellsworth

496 STRATIGRAPHICAL GEOLOGY.

pond, and when it comes in contact with the porphyritic gneiss it rests
unconformably on it. The porphyritic gneiss does not He entirely to the
east of the fibrohte rock, but there are several small areas where it is
entirely surrounded by it. One is on Moulton brook, where the road
crosses it at H. & D. Sanborn's mill; and there are two in Rumney, — one
west of Stinson pond, and another on the north side of Stinson mountain.
This is probably the extension southward of the large area at Ellsworth
pond, most of the porphyritic gneiss being covered up by the fibrolite
rock. As the areas of porphyritic gneiss to which we have referred are
nearly equidistant from each other as far as the strike of the rocks is
concerned, it seems altogether probable that they constitute a synclinal
axis underlying the fibrolite rock ; and it is possible that this may give
us the data for determining the actual thickness of the latter.

In Rumney, except the small area of porphyritic gneiss, a fine-grained
gneiss in the south-west corner of the town, an area of granite or granitic
gneiss north of Quincy station, and a band of granitic gneiss north of
Rattlesnake mountain, the rocks are mica schists or micaceous gneiss,
and they contain either fibrolite or andalusite; the coarse granitic veins
carry beryl. Graphite (black lead) is found in the drift north-west of the
saw-mill near G. L. Merrill's, and probably came from these rocks. The
high bluff of rocks west of the village, and the hills north of West Rum-
ney, are andalusite schists ; they are found south of the river ; but the
rock of Hawks mountain resembles more the common White Mountain
gneiss. In general, the distinction between the rocks of Rumney, and
the Montalban rocks as they occur in the White Mountains and east in
Campton, is very slight. The andalusite schists consist chiefly of quartz,
mica, and fibrolite, or andalusite. The mica is in smaller plates, and feld-
spar, except in the granitic veins, is not so common. In regard to the
porphyritic gneiss, it is to be noted that in Rumney the band that en-
ters the town from the north disappears beneath the fibrolite schists.

In Groton, in the north part of the town, except in the extreme western
part, the rock is entirely fibrolite and andalusite schists. As we go south
it divides, and one band goes south-east and extends into Hebron, where
it is the rock of the ridge of Tenney hill and Crosby mountain ; it out-
crops on the road north of Newfound lake, and here we find some quite
good crystals of andalusite. The other band goes south-west, towards

GEOLOGY OF THE MERRIMACK DISTRICT. 497

the corner of the town. The easterly band does not extend much south
of the north end of Newfound lake, but eastward it is the rock of
Plymouth mountain, where the rock contains fibrolite. East of A. J.
McClure's, and at the town-house, we have fine-grained granitic gneiss.
In the south part of Groton, between the two bands of fibrolite schist, we
have coarse gneisses, sometimes porphyritic. The westerly band of
schist that extends south-west from North Groton, outcrops in extensive
ledges near where the road crosses Cockermouth brook, and it extends
west into the edge of Dorchester. South of Kimball hill, and at G.
Thompson's, the rock resembles the more micaceous of the Montalban
series. Coarse granite veins are quite common in Groton and Hebron,
and some of these carry fine crystals of beryl and mica. In the narrow
band of fibrolite rocks in the south-west part of Groton we no longer find
the synclinal structure that we saw in the broader band northward, but
all the rocks have an easterly dip. Section VI crosses the south part of
Groton, and the dip of the rocks will be given, which will show the rela-
tion of the fibrolite schist to gneiss.

In Orange, a line drawn from near R. R. Smith's south to Grafton,
passing near the outlet of Orange pond, will point out the boundary
between the fibrolite schist and the porphyritic gneiss. Another line,
drawn from near the north-west corner of Orange, and bending to the
west so as to pass just through the border of Canaan, near W, Davis's,
turning eastward to the forks of the road near S. H. Stevens's in Orange,
thence southward to a point between the height of land and Tewksbury
pond, will follow nearly the western boundary of the fibrolite schist.
Here, as southward, we have the Lake gneiss on the west. It will be
noticed that the schist is quite variable in width, being two miles and
three quarters in width on the north, and for some distance southward,
when it suddenly contracts, near the middle of the town, to a band a mile
and a half in width ; and on the southern border of the town it is not
more than a mile wide. In this area most of the strata are nearly verti-
cal, and in the narrower portions it has both an easterly and westerly dip.
There are coarse granitic veins in several places, and fibrolite can gen-
erally be found.

In Grafton the band widens somewhat, and here we have the coarse
granitic veins that have produced so much mica. The rock can be seen
VOL. IL 6^

498 STRATIGRAPHICAL GEOLOGY.

on the railroad near the outlet of Tewksbury pond, and on the hill be-
tween the pond and W. Aldrich's ; and south it is the country rock of
Isinglass mountain. Thence it extends south to Springfield, and has
a width of about a mile and a quarter. Along its entire outcrop it
has coarse granitic veins, and in these openings have been made for
mica. Through the town we have the Lake gneiss on the west and the
porphyritic on the east.

In Springfield this rock is not so easily traced, and in the north part
of the town it seems to disappear altogether. Running southward from
Aaron's ledge to Col. Sanborn's hill there is a band of rocks, but they are
more micaceous than the common fibrolite rock, and as far as they have
been studied no fibrolite has been seen, though the coarse granitic veins
are common.

In Sunapee the rocks between the porphyritic and the common gneiss
resemble those of the common White Mountain series. They can be seen
at the village of Sunapee Harbor, on the road north at J. Newton's, and
south at D. Winn's. Keyser hill, east of the narrow band of porphyritic
gneiss at the village of Sunapee Harbor, is composed of White Mountain
gneisses, sometimes granitic. The porphyritic band is probably an out-
lier of the great area to the south-east. The rock that outcrops near
Union church, in the south part of the town, consists of fine-grained and
micaceous bands, and is followed on the west by common gneiss. It is
closely allied to the typical White Mountain gneisses, and extends south-
ward into Goshen, where it outcrops along the west side of Sunapee
mountain. North-east of Mrs. L. Blood's we have both the micaceous
and granitic gneisses, though the former may be more allied to mica
schist than to gneiss. Here we find a peculiar form of fibroHte, which is
not seen north, but is quite common southward. It is sometimes green-
ish gray in color, is compact, and often has the semblance of crys-
tals, the centre portions of which have been removed by weathering.
East of L. Baker's we have prophyritic gneiss, then the band of mica
schist, and in this is a bed of graphite, from which years ago tons of the
mineral were extracted.

In the south part of Goshen, at J. Glines's, on the road to Washington,
there is a narrow band of fibrolite rock intimately associated with the
porphyritic gneiss. Southward the whole Lempster mountain range is

GEOLOGY OF THE MERRIMACK DISTRICT. 499

mica schist or micaceous gneiss. It contains the compact fibrolite, and
has coarse granitic veins that carry beryl and tourmaline. The strata
have a high easterly dip, and there is common gneiss on the west and
porphyritic gneiss on the east.

The band of mica schist in Marlow is less than two miles in width.
Its northern limit is near Stone pond, and it is limited on the south-west
by the porphyritic gneiss of Bald mountain. Half a mile south of Stone
pond the compact fibrolite is very abundant, and is brought out finely by
weathering. One of the best exposures is south-west, near S. Mathews's.

In Alstead the rock changes somewhat, being more compact and more
gneissic in its character. In the south-east corner of the town it con-
tains coarse granitic veins, where several mica quarries have been worked.
The character of the fibrolite also changes, and is more like the common
variety.

South-west, in Surry, we find Surry mountain composed of rock that is
more like mica schist than gneiss; though it sometimes has the character
of a micaceous gneiss, and sometimes, though rarely, contains fibrolite.
On the west side of the mountain, east of the village of Surry, about three
fourths of the way up, there is a vein, sometimes two or three feet wide,
that carries galena, zinc-blende, and pyrrhotite. It appears also near the
north end of the mountain, at nearly the same level. The southern ex-
tremity of Surry mountain is the limit of this band of the fibrolite rock
southward. The rock of Bald hill, — which seems to be an extension of
Surry mountain northward, although cut off from it by the deep valley of
the Ashuelot river, — resembles very closely the White mountain gneiss,
and probably belongs to the same group of rocks as Surry mountain.
We have already referred to the rocks of Bear Den mountain when
speaking of the pyritiferous schists, but they are hardly distinguishable
from the rocks of Surry mountain, and evidently belong to the Montalban
series.

Then, going south, in the east part of Keene and extending into Rox-
bury, and southward in Marlborough and Troy, we find the White Moun-
tain schists and gneisses. In Keene, on Beech hill, and on the road east
of D. Wood's, we have a micaceous gneiss ;^.also in the hills south-east of
South Keene.

In Roxbury, at school-house No. 3 and on the hills north, we find the

500 STRATIGRAPHICAL GEOLOGV.

same rocks. On the hill east, about a mile from school-house No. 3, we
have a granitic gneiss, and this is succeeded by a pyritiferous concretion-
ary schist. South of school-house No. 3 we have the famous Roxbury
granite, — a granitic gneiss of the Montalban series. There are also quar-
ries along the west base of Horse hill, where the rock is somewhat coarser
in texture. On the road south, perhaps three fourths of a mile west of
Cummings's pond, we have the concretionary schist.

In Marlborough this band of rocks becomes wider, and extends east
along the north line of the town, taking the place of the concretionary
schists of Roxbury, and probably resting on them. Going south-east
from Horse hill in Roxbury, after crossing bands of White Mountain
and fibrolite schists, we strike another band of concretionary schist,
before we reached the line of Dublin, exactly like that in Roxbury; and
this band may extend north through Harrisville and connect with the
Roxbury schist west of Breed pond. If the schist that we find north-
west of West Harrisville is not continuous north-east and connected with
a similar rock in Nelson, then we have an oblong area of White Moun-
tain and fibrolite schists extending into and partly surrounded by concre-
tionary schists. On the south-east side of this area we have fibrolite
schists, and they resemble more the schists of Monadnock than the com-
mon White Mountain schists. If these are connected with similar schist
on the hill north of Harrisville, then we have a band nearly parallel to the
Monadnock range, and separated from it by the concretionary schists.
In the extreme north-east part of Marlborough, on the line of Harrisville
and just south-west of the forks of the stream below West Harrisville, we
find the compact fibrolite, so common in the schists of Marlow. This
band of rocks outcrops to the south-west near L. Blodgett's, and the east-
ern limit here is between Blodgett's and school-house No. 6. From this
point the line separating the two schists runs southward near Meeting-
house pond, thence near the forks of the road north-west of D. Field's.
The boundary here and southward is not so well defined as the southern
limit of the band of concretionary rock west of Monadnock is, in the
south-east corner of Marlborough,

The rock of the western and central part of Marlborough is White
Mountain schists and gneisses. At the glen above the village there is an
extensive exposure of micaceous gneiss. There is a great gorge, with a

GEOLOGY OF THE MERRIMACK DISTRICT. 5OI

wall of rock thirty or forty feet in height, and pot-holes in the ledges
where the water has poured over. The strata are nearly vertical, and
there are granitic veins. South of the village is the granite quarry, and
on account of the arrangement of the mica the rock appears to be bedded.
It has two micas and two kinds of feldspar, — one beautifully striated.
South, along the railroad, there are many outcrops of micaceous gneiss ;
the strata are nearly vertical, with nearly everywhere an easterly dip ;
while along the road south of the old church the dip is westerly, thus giv-
ing a synclinal structure to the Montalban rocks. Here, as elsewhere,
these rocks frequently contain coarse granite in veins. They are quite
numerous on the hills east of Marlborough station. On the west of these
rocks we have a gneiss in the edge of Swanzey that resembles more the
Bethlehem than common gneiss, while on the east, in Marlborough and
in the edge of Dublin, we have siliceous pyritiferous schists.

Rocks of the Montalban series are the prevailing, if not the only, rocks
of Troy, and many of them cannot be distinguished from those found on
the summit of Mt. Washington. We have east of the village a granitic
gneiss of this series that is quarried. The strata are generally nearly
vertical, but the prevailing dip is easterly. The most important thing in
connection with the rocks of Troy is that the Monadnock range meets
Montalban rocks at such an angle as to show their unconformability.
The western boundary of the Montalban rocks of Troy and southward
follows very near the line of Troy and Swanzey, and from near the north-
east corner of Richmond it extends in a curved line nearly to the village
of Richmond ; thence it extends a little south of west, and strikes the
town line perhaps a mile south of Peaked mountain.

In Winchester there is a small area of these rocks in the south-east
corner of the town, and they may extend in a narrow band as far north
as the west side of Stony mountain.

In Richmond all the rocks south-east of the line we have mentioned
belong to the Montalban series, with the exception, possibly, of the band
of rocks that embraces the soapstone. The strata generally are nearly
vertical, and have both easterly and westerly dips, while the strike is
frequently north and south. In some places the strata are twisted and
contorted, and so ferruginous as to disguise the real character of the rock.
South-east of school-house No. 14 is a band of soapstone, included, in part.

502 STRATIGRAPHICAL GEOLOGY.

in hornblende schist. The soapstone is identical with that at Frances-
town, but on account of its hmited area, and sometimes portions of it
containing iron, it has not been worked with profit. When attempts
were made to work it there were two openings, one nearly east from the
school-house, and the other south-east from L. Harris's. The width of
the bed was forty-two feet, and apatite, rutile, pinite, and iolite have been
found, — the pinite in very perfect crystals. At E. Harkness's, near D,
Martin's, N. Putney's, and several other localities, there are coarse gran-
itic veins, and graphite above school-house No. 12. South-east from
Richmond, in the town of Royalston, particularly at Royal cascade, we
have the typical Montalban rocks. In the north-west of Fitzwilliam, ad-
joining Richmond, we have an extension southward of the Montalban
rocks of Troy ; there are outcrops west of S. W. Keith's, at M. Broad's,
N. Howe's, and in many other places. Extending diagonally across the
town we have a band of andalusite rocks, apparently an extension of the
rocks from Monadnock. They outcrop on the road between Bowker
pond and S. Drury's, south of R. Fairbanks's, on the railroad north of
the Richmond road, and in the south-west part of the town at G. Rich-
ardson's. Except the granitic gneisses that are so extensively quarried
near the village of Fitzwilliam, and a few rocks along the railroad, we
shall have to regard this as the limit of the Montalban rocks, unless
the pyritiferous schists of Rindge belong to this series.

The Eastern and Western Bands. The eastern band of fibrolite schist
differs in many respects from the western, yet in some points they are
alike. Most of the rocks of the eastern band are mica schist ; but while
many of the rocks of the western seem to be hydro-mica schist, yet there
are some that are clearly mica schist. The compact fibrolite, common
in the southern part of the western band, is also common in the eastern
band, and is one of its marked characters. The fibrous variety is com-
mon to both. The rocks of the eastern band are very closely allied to,
if not identical with, the range north that includes Mt. Kearsarge and
the Ragged mountains. On the other hand there are many points of
resemblance between this eastern range and some of the rocks we have
described under pyritiferous schists. We have already alluded to an
outcrop of rock north of Harrisville, which seemed to be a part of a
band that extended south-east into Marlborough; but the Monadnock

GEOLOGY OF THE MERRIMACK DISTRICT. 503

range has its northern hmit at the northern extremity of Beech hill,
where it has a dip almost directly north ; but on the same hill south
the dip is north-west. The rock seems more allied to hydro-mica schist
than to the common mica schist, and it contains compact fibrolite.
It is the rock directly east of Monadnock lake, and it occupies an area
of country here at least two and a half miles in width. It is the
rock of the country directly south of Dublin village nearly to Thorndike
pond, and south-west it is connected with the ridge of Monadnock. There
is an outcrop just south-east of the eastern extremity of Monadnock, and
on the road still farther south the rock is more decidedly a hydro-mica
schist than that found elsewhere in this range. Following the ridge of
Monadnock, the rock is quite uniform until we get near the highest point
of the mountain, when it becomes more compact, has fewer cleavage
planes, and contains some chlorite. The fibrolite, though generally pres-
ent, is not so abundant as on Beech hill, and it is the variety that was
formerly called bucholzite. On the north side of Monadnock, probably a
hundred and twenty rods a Httle east of north from the hotel, considerable
quantities of graphite were formerly obtained, but the mine is now nearly
or quite exhausted. The fact that graphite occurs here, would ally the
rocks of Monadnock with the older rather than the newer rocks. On the
north-west side of the mountain, and not far from a mile south-east of L.
Darling's, the rock resembles the micaceous gneiss of the White Moun-
tains, and it contains an abundance of the fibrous variety of fibrolite. The
rock on the ridge extending southward from the summit of Monadnock
is very similar to that on the ridge northward, and it crosses the road
just west of the toll-gate, where it is a very narrow band, and nearly
vertical. Southward, on Gap mountain, we have the andalusite schist
associated with a rock probably intrusive, and also with a dark gneiss.
The schist that outcrops in Fitzwilliam, west of S. Drury's, has a large
proportion of andalusite, and where it was examined had no other rock
with it ; that south of R. Fairbanks's has a fine-grained granitic gneiss ;
on the east and adjacent to it, that near G. Richardson's has the strata
vertical, and with it is a dark gneiss, similar to that on Gap mountain,
and it is probably the same kind of rock as that quarried near the station.

504

STRATIGRAPHICAL GEOLOGY.

Dip of the Rocks of the Montalban Series.
These include the ferrusrinous schists, the fibroUte schists, and the

White Mountain schists and gneisses.

Easton.
At Easton village, N. 82° E. 60°.
On road towards Kinsman Notch (Bun-
gay), N. 83° W. 60°.
Warren.
A mile east of R. K. Clement's, S. 28°

E. 70°.
On Mt. Carr, at head of Hurricane brook,

S. 48° E. 65°.
On crest of Mt. Carr, S. 38° E. 60°.

Wentworth.
On ridge of Mt. Carr, N. 80° E. 58°.
Other dips in Wentworth and in Ellsworth

are shown on section VII.
Rumtiey.
On summit of Stinson mountain, N. 68°

E. 60. North-west side, N. 78°

W. 50°. West side, N. 75° W. 65°.
South-west side of Rattlesnake mountain,

S. 65° E. 80°, and opposite.
Near cemetery opposite West Rumney, N.

87° E. 76°.
Near H. M. Swain's, S. 75° E. 55°.
Near J. C. Burnham's, N. 48° W. 75°.

Plymouth.
On the hill south-west of C. G. Batchel-

der's, S. 68° E. 64°.
Near C. Nutting's, S. 82° W. 65.
Near J. Nutting's, S. 85° W. 58°

Canipton.
On Wolfe hill, above Blair & Sanborn's

quarry, N. 70° E. 58°.
Near Capt. J. Cook's, N. 82° E. 70.

Holderness.
On Mt. Prospect, N. 57° W. 65°.
On north spur of Mt. Prospect, N. 68°

W. 76°.

On Squam mountain, north of road, S.
84° W. 55°.

North of town-house, N. 72° W. 68°.

Near Mrs. T. Shepherd's, S. 38° E. 40°.
Bridgewater.

On the hill near S. Fifield's, N. 58°. W. 74°.

Near J. C. Barrett's, S. 76° E. 70°.
Hebron.

Near E. Woodbury's, S. 68° E. 70°.

Near Tenney hill, S. 76° E. 65°.
Grot on.

North part of Groton, on road to Rumney,
N. 36° W. 75°.

At school-house south, N. 58° W. 63°.

At North Groton the strata are often ver-
tical, but west, they have an easterly
dip, and east, they have a westerly
dip.

At P. Chase's, N. 45° W. 65°.

At D. Esty's, S. 82° E. 80°.
Grafton.

At M. Kilton's, S. 60° E. 72°.

At mica quarry, N. 32° E. 80°.

At west side, S. 50° E. 75°.

At north, S. 63° E. 70°.

k mile south-east of J. Martin's, S. 78°
E. 70°.

At Alger hill, N. 62° E. 75°.

At H. Bullock's, S. 38° E. 50°.

At Prescott hill, N. 82° E. 40°.

I mile north-east of T. Foss's, S. 65° E. 70°.

At Mrs. Arvin's, S. 62° E. 78°.

At Tewksbury pond, S. 33° E. 75°.
Orange.

At J. Eastman's, N. 82° E., variable.

North-west of J. W. Hooper's, S. 6o<' E.
70°.

GEOLOGY OF THE MERRIMACK DISTRICT.

505

At school-house No. 7, N. 40° W. 78°.
Opposite P. Stevens's, S. 6° W. 80°.

Shu a pee.
Near Union church, N. 80° W. 76°.
Near D. Winn's, S. 82° E. 60°.

Goshen.
Near Mrs. L. Blood's the westerly dip is
probably local, as elsewhere here, and
at the graphite mine the strata have a
high easterly dip.

Leinpstcr.
At signal, Mt. Lempster, S. 76° E. 62°.
A mile north-east of same, S. 53° E. 50°.
A mile north of D. Hall's, S. 36° E. 75°.
Near T. Wellman's, S. 52° E. 72°.

Acworth.
Near L. Morse's, N. 80° E. — contorted and

variable.
Second road north of Beryl mountain, N.

82° E. 15°.
North end of Beryl mountain, N. 66° E.

10°.
Near J. Buckminster's, S. 36° W. 46°.
Near G. H. Gassett's, N. 48° W. 50°.
Near C. W. George's, N. 80° E. 40° ; half
a mile south, S. 53° E. 15°.
Marloiv.
Just south of Stone's, S. 50° E. 65°.
i mile south of Marlow hill, S. 25° E. 70°.
Near S. Mathew's, S. 2° E. 70°.
At Gustin pond, 2)T E. 60°.

Stoddard.
On Stoddard heights, at signal, N. 6}° W.
75°.

Gilsum.
Near R. Nicols's, S. 68° E. 55°.
At school-house No. i, N. 82° E. 32°.;
also a fine-grained gneiss, S. 66° E.
70°.

Surry.

On west side Surry mountain, opposite the
village, N. 80° W. 60°.
VOL. II. 64

On Bald hill, S. 80° W. 62°.

South of Lily pond, S. 75° W. 70°.

h. mile north of the Austin place, S. 88° E.

70°.
At the Austin place, N. 82° W. 60°., and

variable.

Roxbnry.
Near school-house No. 3, N. 80° E. 40°,

Nelson.
At Page's, N. 53° W. 40°.
At N. H. Hardy's, N. 88° W. 45°.
At M. Wilson's, N. 68° E. 48°.

Marlborough.
Fifty rods south-west of Cummings pond,

N. 55° E. 64°.
At the Glen, N. 48° W. 60°.
At J. H. Knight's, westerly.
South of brook near J. P. Smith's, N. 28°

W. 46°.
Sulpher spring, westerly, nearly vertical.
At L. Blodgett's, N. 58° W. 60°.
At Wm. Tenney's, S. 82° W. 20°.
At Granite quarry, S. 65° E. 60°.
At T. Tollman's, S. 85° E. 65°.
At A. Bemis's, S. 80° E. 50°.
h mile north of B. Morse's, N. 76° W. 55.

Troy.
At S. Tollman's, S. 68° E. 50°.
Near J. Bemis's, N. 62° E. 80°.
At W. Boyden's, N. 72° W. 62^.
At L. Wright's, N. 85° E. 70°.
At school-house No. i, N. 68° W. 55°.
At M. K. Tapley's, N. 72° W. 60°.
Gap mountain, west side, north peak, N.

80° E. 70°.
Top of ridge, S. 78° E. 75°.
On south peak of Gap mountain, N. 70°

W. 72°.

Dublin.
South-west of Monadnock pond, N, 28°

W. 62°.
North end of Beech hill, N. 40°.

5o6

STRATIGRAPHICAL GEOLOGY.

South-east side of Beach hill, N. 42° W.
30°.

South end of Beach hill, S. 35° W. 36°.

South of the east end of Monadnock pond,
i mile south-east of L. Darling's,
N. 68° W. to N. 12° E.— variable.

East side of Mountain brook, N. 12° to
N. 36° W. 35°.

In the pasture on extreme north-east spur
of Monadnock, N. 50° W. 18.

I of way to north peak of Monadnock from
the lake N. 80° W. 35°.

North peak of Monadnock, N. 72° W. 45°.

A mile north-east from summit of Monad-
nock, S. 84° W. 65°.

East of A. H. risk's, N. 46° W. 82°.

South of Wood's brook, N. 48° W. 70°.

7qfrey.
i mile north of summit of Monadnock,

N. 82° E. 50° ; summit, N. 36° W; 60°.
i way to Mountain house, N. 38° W. 20°.
h way to Mountain house, N. 48° E. 25°.
Near toll-gate, N. 38° W. 60°.
Near J. W. Harris's, N. 62° W. 74°.
A mile north-east of Jaffrey centre, N. 36°

W. 50°.
East of Thorndike pond, N. 43° W. 50°.
Saw-mill on Contoocook river, N. 85° W.

53°.
At Capt. E. Prescott's, N. 36° W. 55°.

50 rods south of A. Baker's, N. 20° to N.
50° W. 62°.

At the village, S. 53° W. 70°.
South-east of J. R. Bixby's, S. 53° E. 20°.
At school-house No. 7, S. 48° E. 55°.
At J. T. Hale's, S. 8° E. 72°.
i mile east and south of the road, N. 8°

W. 50, — variable and contorted.
Near Gate's, S. 80° W. 45°.
South-west of village, and west of railroad,

S. 75° W. 50°.

Fitz'iuiUia7n.
North of State Line station, N. 58° W. 45°.
At W. F. Terry's, strike north and south ;

strata vertical.
At G. Richardson's, N. 63° W., and opp.
On road west of S. Drury's, S. 8° E. 65°.
At M. Broad's and H. F. Hildreth's, N.

80° W. 40°.

Richmond.
At J. Hill's, N. 80° E. 60°.
At Z. Bowen's, N. 82° E. 40° to 70°.
At E. Harkness's, S. 58° E. 48°.
At M. Allen's, S. 68° E. 80°.
At W. Wright's, S. 80° W. 74°.
At A. Keton's, N. 75° E. 65°.

Winchester.
On Peaked mountain, N. 85° E. 75°, and

vertical.
On Stone mountain, west side, N. 78° E.,

nearly vertical.

Hill north-west of Haskell's, N. 63° W. 70°.

[Note. The quartzites and quartz conglomerates occurring along the western border
of this district have been described in connection with those of the Connecticut Valley
district, pages 416-421.]

Intrusive Rocks and Vein-Stones.

Quarts. There is a band of quartz that has its northern limit on Giles
pinnacle in Grafton. Southward there are extended outcrops in Gran-
tham, Unity, Surry, and Kecne. This band of quartz has some marked
peculiarities which distinguish it from all the other rocks that we have
described. There are, however, two bands of rocks in the eastern part of

GEOLOGY OF THE MERRIMACK DISTRICT. 50/

the state that are its equivalents. The northern area, that in Grantham
which forms the elevation known as Giles pinnacle, may be three hundred
and fifty yards in length, and is probably five hundred feet in width. As
the outcrop is surrounded by drift, this limit may be far too small, and
the drift also prevents our knowing what rock the quartz penetrates. The
nearest rocks, however, are common gneiss. The rock is not often a pure
white quartz, but is generally of a dull yellow or of a reddish color. In
many places it contains cavities that are lined with quartz crystals, and
it frequently encloses decomposed feldspar. Sometimes there is a ten-
dency in the rock to a banded structure, though this is not common.

The outcrops of the quartz in Grantham are not so prominent as those
of Grafton. Here the quartz has been worn away nearly to the level of
the other rocks, and everywhere that we have seen the quartz it rises
above the rock it penetrates in proportion to its width. The character of
the rock is very much like that of Grafton. It outcrops on the road that
runs south-east from the Methodist church, and at D. S. Hastings's where
it forms quite a hill, and on both sides of it we have gneiss. It can be
seen west of N. Shaw's, and southward it crosses the road at the forks
near W. G. Winter's, and below, at R. Winter's, there is a prominent ledge.

In Croydon, north-west of East Village, near W. R. Bartlett's, we find
the quartz penetrating the protogene gneiss, and it contains iron ore both
limonite and hematite. The masses are sometimes four or five inches in
diameter. The quartz is several rods in width, and from the principal
area it sends off veins into the surrounding gneiss.

The next outcrop southward that we have examined is on Quimby hill
in Unity. In width it is much more extensive than the rock in Gran-
tham. It is more compact, and has fewer cavities. There is also another
outcrop on the hill directly south of Quimby hill. The drift conceals all
the rocks except the quartz, but as there is a protogene gneiss east, it is
more than probable that the quartz penetrates it here as in Grantham.
We also find quartz at the south end of Perry mountain, and some of it is
very white. It is here very near a band of quartzite. This quartz is
probably the source of the very white quartz boulders scattered through
Langdon.

In the south-west part of Surry there is quite an extensive area of
quartz, and at Mine ledge it attains a greater width than anywhere else

508 STRATIGRAPHICAL GEOLOGY.

along the line of its outcrop : we have here nearly all the features that
characterize the rock. At the extreme north end of Mine ledge, perhaps
half a mile south-east of the house of E. Grain, Jr., there is a narrow band
of the rock, with veins penetrating the protogene gneiss in every direc-
tion, making in many places a complete breccia. Southward the band of
quartz widens, until opposite school-house No. 4 it is not far from six hun-
dred feet in width. Just north of the road that passes through Mine
ledge, in the quartz we find quite a quantity of iron ore, chiefly limonite,
that forms botryoidal and mammillary masses on the quartz. From this
circumstance this quartz hill received the name it bears, though the ore is
not found in workable quantities. On the east side of the ridge there is
a high and precipitous wall of rock, and opposite this, on the west, the
ridge is quite steep. Besides the brecciated character of some parts of
Mine ledge, we find not only in the rock here, but elsewhere, that the
quartz encloses feldspar, generally partially decomposed, as though the
quartz had been formed in a great fissure, and that the vapor or solution
that carried the silica had penetrated the rocks adjoining, and absorbed
all but a remnant of the feldspar.

Southward, on the railroad, instead of being concentrated mainly in one
vein, there are several. In the cut below the crossing, in the corner of
Keene, we find two veins with chlorite schist between : one of these
veins has well defined walls. In the Surry or "mile cut" the principal
vein of quartz is from twenty to thirty feet wide, is a breccia in part, and
is on the line of a fault. On the east side it abuts against hornblende
schist, while on the west there is gneiss, and in this there are several
small veins of quartz. Both of the larger veins follow the line of an axis
or a fault. South of the railroad, one band of quartz extends southward
along the east side of Gray's hill, and soon disappears. Another band
can be followed over Gray's hill and down on the south-west side. There
is an outcrop of the quartz at A. Parker's and at the Barker place in
Westmoreland, and also west of J. Hyland's, but all of these are compara-
tively narrow.

On the east side of the Ashuelot river, in Keene, there are several out-
crops of the quartz, — one north-east of the cemetery, another south, and
still another near South Keene. On the east side of West mountain,
on the slope toward the Ashuelot, there are extensive outcrops. It is

GEOLOGY OF THE MERRIMACK DISTRICT. 509

nearly continuous, and a brook near the line of Keene and Swanzcy
crosses it, but it does not extend far into Swanzey.

In Chesterfield, near C. A. Lincoln's, we have small veins of quartz ;
and at the forks of the roads south of J. Putnam's the veins have consid-
erable width, and contain many cavities with quartz crystals. Here, as
elsewhere, the quartz penetrates the protogene gneiss. This locality is
the southern limit of this peculiar vein quartz, as far as we have been able
to trace it.

From our study of this rock we conclude (i) that these veins are
endogenous, i. e., the material of which they are composed was derived
from the adjoining rocks and from the deeper parts of the fissure ;
(2) that the vapor or solution from which the silica was deposited was
strongly alkaline, — so much so that in some cases it absorbed the silica
of the adjacent rock ; and that this was re-deposited with that already
held in solution, enclosing portions of the feldspar of the county rock.

Granite. There are seven well-marked areas of granite in this topo-
graphical district. The boundary of each, however, does not seem to be
so regular as that of the areas of granite in the central and eastern part
of the state. Here, except that in Roxbury, the areas are much longer in
the general direction of the strike of the rocks of the country than across
it. At Sunapee and Fitzwilliam they differ not only from those east,
but also from others in this district, by having several different kinds
of rocks immediately associated with the granite.

Specimens of rock from different localities vary in the coarseness or
fineness of their mineral constituents rather than in their composition ; —
at least, examining the specimens with a common lens, about all we can
say is, that one is coarser or finer than another; but microscopic analysis
may show much greater distinctions.

The most northern area is in Rumney. Immense boulders of the gran-
ite lie along the side and at the base of Rattlesnake mountain. These
boulders are quarried ; and it is wonderful how they have withstood the
action of the atmosphere through the ages that they have been exposed
to its influence. Many of them are scarcely affected by weather, showing
that it is one of the very best of our granites. North of Quincy station
there are ledges of granite, but the rock seems to be of a different char-
acter, more quartzose, and not so suitable for working.

510 STRATIGRAPHICAL GEOLOGY.

Farther east, just in the edge of Rumney and extending into Plymouth,
is Wolf hill ; this is almost one mass of granite. It is in many respects
unlike any of the other fine-grained granites, and seems to be metamor-
phic rather than intrusive.

In Sunapee the granite is confined to a small area bordering on Suna-
pee lake, south of Sugar river, but there are several kinds of rock in the
immediate vicinity of this granite. Three quarters of a mile from the
outlet of the lake we have a typical variety of the White Mountain schists ;
between this and the lake there is porphyritic gneiss ; and with the gran-
ite at the quarry south-east of the Harbor there is a dark-colored gneiss
that belongs to the upper division of the Bethlehem gneiss. Then on
Keyser hill and towards the lake we find porphyritic gneiss again. When
this locahty was visited, the granite seemed to me to be intrusive, and,
from my study of similar rocks elsewhere, we have had no reason to
change our opinion. About a mile and three quarters south of the Har-
bor, and on a road running east and west, there is quite an extensive
quarry, and the stone obtained here is one of the best for many purposes
of any that is found in the state. It is fine-grained, the colors are bright,
and the rock does not have the dull appearance characteristic of some of
our granites. South-east of this last quarry, and near E. Woodward's,
there is a very dark-colored granite composed largely of quartz and mica,
which resembles very closely a granite associated with fine-grained granite
on the Nulhegan river in Vermont. A little south-east of this, on the
road nearest the lake, we find porphyritic gneiss.

In Goshen the amount of granite is very small, and the area is on the
road in the east part of the town just north of Chandler brook. The
rock is rather coarse, and contains a much larger proportion of white
mica than most of our granites. There are no outcrops of other rocks in
the immediate vicinity, though to the south-east we soon come to porphy-
ritic gneiss, fibrolite, and ferruginous schists.

In Acworth, in the south-west corner of the town and north of Cold
river, there is a very limited area of granite, and it is known as Osgood's
ledge. The surrounding rocks are quite unlike those associated with the
granites elsewhere. On the north and west we have quartzites and
schists of the Coos group, while on the south we have rocks that proba-
bly belong to the Montalban series.

GEOLOGY OF THE MERRIMACK DISTRICT. 5II

The granite of Roxbury occupies an area in the south-west part of the
town, on the road running north-east from Cummings pond. Instead of
extending north and south, as most of the granite areas do, it extends
rather east and west. On the western slope of Horse hill, in several
places, the rock has been uncovered and quarried to some extent. The
joints are not so numerous as in many other quarries ; the principal ones
have a gentle inclination northward, and are from two to three feet apart,
while along the face of some of the quarries scarcely a vertical joint can
be seen. The rock here is somewhat peculiar in that it contains a few
bright garnets. From hand specimens one would be disposed to think it
was a vein-stone rather than the country rock.

The granite extends northward, and there is an outcrop south of the
stream near G. Nye's, and probably this is its limit in this direction.
Westward from Horse hill, west of the road and south of Roaring brook,
is the Nye granite quarry; and a short distance south, but on higher
ground, is the quarry of the Keene Granite Company. The rock from
the two quarries does not differ very much, though that from the latter
is somewhat finer in texture than that from the former. The rock has a
brighter look, and the joints that run nearly horizontal are not so near
together, so that blocks of immense thickness can be raised. About an
equal amount of black and white mica, the bright colors of the feldspar
and quartz, and its pleasing appearance when cut, make it one of the
most attractive of our granites. Its use in the construction of the capitol
at Albany shows that it is appreciated. The rocks on the north, east, and
south, at least, are those of the Montalban series.

It is quite probable that the granite of Roxbury extends across the
branch of the Ashuelot into Keene, since there is an outcrop of granite
on the Lawrence place. The rock here is very much jointed, but was
used in the construction of culverts and abutments of the Manchester &
Keene Railroad. On the hill south-west of this ledge we have a dark
granite similar to that found in Sunapee. The next area of granite going
southward is in Marlborough, south of the village. This is in shape more
like the common outcrops of Concord granite in the central and eastern
part of the state, and it is surrounded by the schists or gneisses of the
Montalban series. We suppose this to be a typical variety of the granites
of this section of the state. It is composed of light gray quartz, of ortho-

512 STRATIGRAPHICAL GEOLOGY.

clase and oligoclase feldspar, and has both black and white mica. The
rock here appears to be stratified, on account of the seams of mica that
run straight through it at an inclination easterly of sixty degrees.

But there are places here, as elsewhere in granite, that the mica
occurs in patches about in the rock quite irregular, and more often bent
than in straight lines. Sometimes it even occurs in nodular masses, so
these lines of mica cannot be regarded with any degree of certainty as
lying in the plane of bedding. A quarry in this rock is one of the oldest
in this part of the state. A rock that withstands the weather and retains
its freshness after years of exposure develops qualities that give it the
highest recommendation as a building stone. That this rock has these
qualities is shown in some of the county buildings in Keene.

In Troy the granite is largely covered by drift, but there are several
places where it appears on the east and south-east of the village. The
rock is fine in texture, and is a very desirable stone. The rock on the
west is the schist of the Montalban series. Towards Monadnock there
is a dark granite, and on Gap mountain it is associated with andalusite
schists.

Southward, in Fitzwilliam, there is quite an extended area of granite.
The northern outcrop is at the Fitzwilliam Granite Company's quarry,
about three quarters of a mile north of the village. At the principal
opening the rock is of a coarser texture than that found elsewhere, but
for some purposes it is a superior stone. Just north of this, on the east
side of the road, there is a very fine-grained rock, and this is in contact
with andalusite schist. The most important outcrops of granite are on
or near the railroad. It extends up the road about eighty rods above
Angier's sheds, and, where it comes in contact with the schist, is one of the
most interesting points for study. Below the Richmond road the railroad
cuts the granite, and then south of the road we have extensive quarries
which produce some of the best granite that we have. The immense
blocks that are raised here show that the joints are not so frequent as
in most of our quarries. The fresh, brilliant colors of the mineral con-
stituents of this rock make it exceedingly desirable as a building or as
an ornamental stone. On the hill south of the railroad station, and on
its northern slope, is one of the oldest quarries in Fitzwilliam. The rock
is cut by numerous joints, the planes of which correspond very nearly

GEOLOGY OF THE MERRIMACK DISTRICT. 513

with the slope of the hill. This jointing enables the quarrymen to
remove immense slabs that are only a few inches in thickness. In parts
of the quarry, however, the joints are not so frequent, and large blocks
for building or other purposes can be obtained. At the quarry on the
eastern slope of the hill the joints are not so frequent, and, among the
other desirable qualities of the rock obtained here, it is susceptible of a
high polish.

With this light granite there is a dark rock that is extensively quarried.
This rock we suppose to be a gneiss, and a more specific description than
that already given will naturally come in the chapter on building-stones.

A section through the hill south of the station shows the dark gneiss
on the south-east and the light gray granite at the quarries. But, a few
rods north-west of the principal quarry worked by Mr. D. M. Reed, he
has made an opening to obtain the dark gneiss ; and here it is that we not
only find the light gray granite in contact with the dark gneiss, but many
veins of the granite penetrating the gneiss. The light gray granite is
certainly intrusive here.

On the railroad, in a cut about ninety rods above the Richmond road,
we have an exposure of the granite and the schist. On the right hand,
as we enter the cut from the south-east, we find the schist nearly vertical,
and extending to the bottom of the cut. But a few steps, and the granite
suddenly appears, three or four feet above the rails, and it gradually
rises until it reaches the surface of the ground. Except at the top of the
cut the strata of the schist stand nearly vertical on the granite. After
extending a short distance along the surface the granite is again capped
by the schist, and soon disappears altogether.

Starting again from the south-east, on the left opposite the schist, the
strike of which should carry it across the cut, we have nothing but gran-
ite, and we find the schist again only as we pass out of the rock cutting.
Metamorphism may explain what we see here ; but that the granite is
intrusive is more probable.

Another interesting feature in the rocks here is, that below the Rich-
mond road the porphyritic granite or gneiss is very near the light grey
fine-grained granite, the intervening space being covered with drift.
The porphyritic rock elsewhere seems to be stratified ; but we have here,
on the road from the station to the village, immense boulders of the
VOL. iL 65

514 STRATIGRAPHICAL GEOLOGY.

porphyritic rock enclosing what appear to be rounded fragments of the
dark gneiss, some of which are a foot in diameter. But whatever may
ultimately prove to be the true character of these rocks, this section, from
the variety of the rocks and their relation one to the other, will always
be of interest.

Granitic Vein-Stones. Although there are many granitic veins in the
east part of the Merrimack River Topographical District, yet there is one
that can be called preeminently the granitic vein. It is nearly coexten-
sive with the fibrolite schist, and follows mainly the axis of a great fold in
the strata. It is important, as it contains the workable mica quarries of
the state, and many interesting minerals. It is developed to a greater or
less extent from Warren to Lempster. It first becomes noticeable on the
crest of the ridge of Mt. Carr, where it contains rose-colored quartz. It
probably follows this ridge southward, as it is found in Wentworth where
the section crosses it.

North of West Rumney and east of J. Sawyer's, there is a vein that
contains beryls, some of which are four inches in diameter. They occur
chiefly in the feldspar, are of a yellowish color, and are not very brilliant.
There are large boulders with granitic veins on the north-east side of
Rattlesnake mountain, and these contain beryl. On the hill south of
West Rumney we find the vein, and it continues southward in Groton.
Near S. D. Southwick's some brilliant beryls have been found ; some of
the larger specimens are six inches in diameter. In the midst of the
granitic vein at Southwick's there is a bed of arsenopyrite about a foot
across. South, at H. N. Hall's, west of the house, the vein is composed
largely of quartz ; and some of the beryls found have their lateral axes
two and a half inches in length. Following this vein southward we find
large crystals of mica, some of the plates being fifteen or eighteen
inches across. East of A. J. McClure's there is a granitic vein in
granitic gneiss. From this vein some brilliant beryls and good crystals
of mica have been obtained. A vein in the south-west part of the town,
which is probably a continuation of the one at Hall's, contains plumose
mica.

East, in Hebron, on the ridge running south from Crosby mountain,
there is an extensive vein that carries beryl. Large crystals have been
found, but they are generally of a dull greenish color. By patient search

GEOLOGY OF THE MERRIMACK DISTRICT. 515

and some labor in this and the towns just mentioned, many brilliant
crystals of beryl could undoubtedly be obtained.

The next outcrop examined was southward, in Orange, near P. Ste-
vens's. Here the vein was formerly worked for mica. Beryls were
obtained, and large crystals of tourmaline are still found ; also mica,
apatite, and albite, the variety Clevelandite.

Grafton is better known than any of the towns through which this
granitic vein runs, and many years ago it became famous for its mica
and its beryl. There is a vein on the ridge a little south of west from
M. Kilton's, which extends northward ; and south, on Isinglass mountain,
is one of the oldest mica quarries in the state, it having been worked
almost continuously for the last thirty-five years. Some of the strata
adjacent to the vein were evidently changed contemporaneously with its
introduction, where they come in contact with the vein rock, having
been bent, and also changed in texture. We find here beryl, tourmaline,
albite, apatite, and triphylite. On the east side of the ridge of Isinglass
mountain, and north-west of T. Foss's, there has been an opening made
for mica within a few years ; and here large beryls are found. On Alger's
hill, which is almost directly south from Isinglass mountain, and across
a deep ravine, we find the granite vein on the crest of the ridge ; and
here the largest known beryls in the world have been found. One hex-
agonal prism from this locality weighs 2900 pounds, and measures four
feet, three inches in length, with one diameter of thirty-two inches and
another of twenty-two. A still larger crystal was partly dug out, but
being left exposed to the weather it fell to pieces. It measured forty-five
inches by twenty-four in its diameters, and was calculated to weigh
two and one half tons. On a hill south-west of Hale pond recent exca-
vations have been made for mica, and here formerly many fine beryls
were found.

In Springfield the granite can be seen on Aaron's ledge, and it extends
south-east towards N. Heath's. At J. W. Hill's mica has been worked,
and the quarry is not yet exhausted. North of N. Heath's black tourma-
line of remarkable size have been obtained. One crystal in the cabinet,
with a perfect termination, is five inches in diameter ; another, somewhat
fractured, is about five and a half inches.

Southward, there are no marked granitic veins in Sunapee or Goshen,

5l6 STRATIGRAPHICAL GEOLOGY,

that^we have seen, but in Lempstcr, north of the signal on Lempster
mountain, there is one of considerable size that carries beryl.

The vein in Acworth that has been celebrated many years on account
of its beryls, which have been widely distributed in this country and in
Europe, seems to be in altogether a different line of fracture from the
one we have followed, though the rock in which it occurs may belong to
the same series. The locality is known as Beryl mountain, and is on
the south side of Cold river, a mile south-west of South Acworth. The
vein is composed largely of quartz, some of which is rose-colored. The
excavation made for mica and beryl is on the north side of the hill, near
the top. The opening seems like a fairy grotto, fallen somewhat to
decay ; for it has been made in the pure white quartz, and in this are set
the beryl, several of which can still be seen. In 1830 Prof. C. U. Shepard
visited this locality and obtained a part of a crystal, the whole of which
he estimated to weigh two hundred and thirty-eight pounds. He sup-
posed this to be the largest crystal noticed up to that time. The vein
here seems to be confined to. the immediate vicinity of Beryl mountain.

Southward, in Alstead, are several veins, but they are confined to the
east part of the town. On the road south of Mrs, S. Whitcomb's there
have been several openings made for mica, and black tourmaline is abun-
dant with the mica. At D. Knight's there is an opening, and at J. A.
Kidder's mica has been quarried. The most extensive excavations, how-
ever, are about half a mile west of S. Goodhue's. The vein extends south
of where it has been worked for mica, and the quartz, often translucent,
forms in this quite a distinct band by itself. An analysis of the feldspar
from this locality by J. D. Whitney, gave silica, 70.84 ; alumina, 21.20;
soda, lime, and oxide of iron, 7.97.

Fine crystals of beryl are found, and perfect crystals of tourmaline
enclosed in the mica, and sometimes the tourmaline is found in the adja-
cent schistose rock. Southward, on Bald hill, in Surry, there is a coarse
granitic vein, but it is not known to contain any minerals of special
interest ; and farther than Bald hill we have not been able to trace this
vein.

There are other beryl-bearing veins, but they are generally small in
size compared with those we have mentioned. There are some in Sulli-
van : one can be seen at Weathron & Cordney's. They are also found in

GEOLOGY OF THE MERRIMACK DISTRICT.

517

Marlow. There is one in Marlborough, at L, Blodgett's, where there are
small but brilliant crystals, and another near the summit of Monadnock.
These are among the most important we have seen.

There is one thing of special interest that we have noticed in regard to
the position of the larger crystals of beryl. We find that all those above
five inches in diameter have their vertical axes perpendicular, or very
nearly so, to the plane of the horizon. If the strata were in their present
position at the time of the formation of the vein, and the material of
which it is comprised was derived from the adjacent rocks, this would
seem to be the natural position of the crystals.

3Stie

■Sheet

J H. RAE.

Improvement in Voltafc Amalgamators for Gold and Silver

No. 123.932. Patented feb. 20, 1872.

\vvv»,n.\««.

CHAPTER VI.

GEOLOGY OF THE MERRIMACK DISTRICT SECOND PART.

InYriHE description of the geology of the Merrimack district is pre-
J^ sented in two chapters on account of different authorship. The
dividing Hne between the areas described is the western boundary of
the largest range of porphyritic gneiss, or that producing the high land
between the Connecticut and Merrimack rivers. The geology of the
territory west of this boundary has been already presented in Chapter V.
The limits of the whole district have been stated in the chapter upon
Topography. Speaking geographically, it may be said the area to be
described in the present chapter is that of Merrimack and Hillsborough
counties entire, with a few towns from Rockingham, Belknap, and Graf-
ton. For convenience, the whole of the porphyritic gneiss of Ashland,
Meredith, etc., and also the sienite of the Belknap mountains, will be
described in the account of the Lake district. Chapter VH.

The formations occurring in the Merrimack district, as thus limited, are
I. Porphyritic gneiss. 2. Lake gneiss. 3. Montalban series, including
the Concord granite. 4. Ferruginous schist. 5. Andalusite mica schist,
with coarse granitic veins. 6. Rockingham mica schist. 7. Kearsarge
andalusite group. 8. Merrimack group, including a little clay slate.
There are no eruptive rocks in this area of sufficient importance to find
a place upon the map.

I. Porphyritic Gneiss.

The largest area of this formation in New Hampshire is that commenc-
ing on the north in Groton, expanding at Grafton, narrowing in Wilmot,

GEOLOGY OF THE MERRIMACK DISTRICT. 519

reaching* its greatest breadth between Washington and Henniker, and
coming to a point southerly in Jaffrey. It is sixty-one miles long, fifteen
wide in its broadest part, seven and a half in Danbury and Grafton, and
three and seven tenths in Wilmot. This area represents the height of
land between the Connecticut and Merrimack rivers, which has been
stated heretofore to constitute the first territory in the state that was
redeemed from the primeval ocean. The normal structure of this mass
should be anticlinal.

Besides this principal mass there are certainly eleven smaller areas, (i)
Bean's hill mass, in Salisbury and Warner ; (2) along Schodac brook, in
Warner and Webster ; (3) a smaller one in the same towns farther south ;
(4) Blackwater river range in Webster ; (5) (6) the continuation of the
same in the hill back of Tyler station, and near the village of Hopkinton ;

(7) the largest one next to the main ridge, in the north part of Weare;

(8) north-west from Oil Mill station, Weare, perhaps continuous with the
outcrops in the north part of New Boston ; (9) a little known area in
Pelham ; (10) in East Concord; and (ii) in Alexandria.

The western boundary of this larger area has been sufficiently well
defined by Mr. Huntington on page 469. There are also a few small
outliers west of it, as on the west side of Moosilauke in Benton, the north
part of Rumney, three miles west of Sunapee lake, one about three miles
north of Washington centre, the large range from the east part of Lemp-
ster to Marlow, a tract between Thorndike and Gilmore ponds in Jaffrey,
and five small patches in Fitzwilliam, besides the oval district in Chester-
field and Winchester. These will not be farther alluded to.

The prevailing rock of this formation is the characterisic gneiss full of
distinct crystals of feldspar. More than one species of feldspar may be
present. The different areas are characterized by special features of size
of crystals, their arrangement, or frequency of occurrence, so that it is
possible to identify the source of boulders that have travelled several
miles. Other layers consist of ordinary gneiss, ferruginous schists, and
mica schists passing into quartzite. These associated rocks occasionally
predominate, and the perplexing query often arises, Where shall we draw
the line between this and the superior formations .'' Rocks repeat them-
selves in different ages, so that we have mica schists, etc., associated with
the oldest as well as the newest formations, and it is not always possible

520

STRATIGRAPHICAL GEOLOGY.

from hand specimens to particularize the period. There are reasons for
believing the porphyritic type of gneiss may not be the very oldest rock
of the state, as instanced upon page 472. It was quite early remarked in
one of the annual reports that this porphyritic rock seemed to have been
thrust in between older strata. There are two areas of gneiss included
within the territorial area of the older mass in Bradford, Warner, and
Henniker. In other cases, an associated rock may be specified, though
not delineated upon the map. It is a matter of regret that this principal
area of porphyritic gneiss has been only slightly examined. Our studies
upon it were mostly confined to the early years of the survey, before it
was understood to be a stratified rock. Our observations of dip are
therefore scanty, and its stratigraphical relations not well worked up.
Then, latterly, also, the territory lay between the district being explored
by two of us, and hence it was neglected.

Messrs. Whitney and Williams, in a description of the section from
Portsmouth to Claremont, speak thus of this rock : " Large boulders of
porphyritic granite are very numerous over the surface, from the West
Parish of Concord to the centre of Warner, where we find the rock itself
in place. It is a peculiar rock, having large crystals of feldspar uniformly
distributed through its mass ; they are often glassy, so as to furnish beau-
tiful and striking specimens. This bed of granite extends across the
state in a general N. E. and S. W. direction ; it is from eight to ten miles
in width, though often interrupted with veins of granite of various tex-
ture, often very coarse grained, and containing occasional beds of mica
slate. * * * This rock continues, on this sectional line, about three
miles west of Newbury, where it is replaced by mica slate." Final
Report, by Jackson, p. 51.

In our second report a range was represented as extending from Wa-
terville to Jaffrey, connecting across from Danbury to New Hampton,
and not extending northerly from Danbury to Groton. Subsequent
observations showed the existence of two instead of one principal range,
and that no visible connection can be found between them. The inter-
vening Montalban schists may be underlaid deep down by a synclinal
basin of the older rock. The height of land in Springfield, New London,
and Sunapee is represented on the map as consisting of the Lake gneiss,
the porphyritic rock curving around it through Wilmot. I do not feel

GEOLOGY OF THE MERRIMACK DISTRICT. 521

certain that we should not regard the Springfield gneiss as a part of the
porphyritic group. Lithologically, it is more like the Lake division.
Rarely crystals of feldspar are disseminated through it. The Montalban
section of rocks carrying coarse granitic veins is also cut off by this
Springfield gneiss.

We have four or five sections crossing this porphyritic range. At the
north end, the formation is poorly exposed in Groton, on Cockermouth
brook, and the positions are represented upon Fig. 82, Plate XXL
The strata are said to dip about 30° E., in the fork of the road east
of Kimball hill. On the west the next ledges are of mica schist, dip-
ping 50° and 60° N. 40° W. Hence, there may exist a strongly marked
unconformity here. The rock through this valley in Groton contains
many fine-grained gneisses ; also, ferruginous schist west of A. Fox's and
the saw-mill, where the dip is 50° E. The rock is not seen in Hebron.
This section, therefore, makes the dip of this rock in Groton essentially
monoclinal. Farther north it is not seen, that is, for a distance of over
nine miles, when we come to the Moosilauke-Kinsman range. It is
probably exposed in the valley of Cockermouth brook, just at its northern
extremity. The country north rises rapidly, and constitutes a high ridge
about eight hundred feet above the porphyritic outcrops. This elevated
mass of rock is probably a later formation, occupying a natural depression
in the older rock. There may be an inverted anticlinal underneath the
Kimball hill schists, in order to enable the porphyritic rock to present a
proper face towards the easterly dipping gneisses of Dorchester.

The next section traversed is from the north end of Crystal lake in
Enfield across Grafton and Danbury (Fig. 83). At the west end are strata
of the fine-grained Bethlehem gneiss, with easterly dips. On the east side
of East hill there is a gneiss somewhat porphyritic in aspect, dipping west.
The rock is like this for two miles into Grafton, but the dip has changed
to east. Then we pass the mica-bearing rock with its very coarse granite
veins, dipping 53° S. 20° E. and 70° S. 80° E. This rock is believed to
mark the place of a synclinal. The first ledges seen after leaving Grafton
Centre are of genuine porphyritic gneiss, but I have no observation
recording their position. The dips are believed to be easterly. In
Danbury there is a south-west dip near S. Howe's, a mile north-east of
the section. At the east end of the formation, half a mile north-west

VOL. IL 66

522 STRATIGRAPHICAL GEOLOGY.

from Bog pond, the dip is 80° S. 70° E., and it is succeeded by a hard
quartzite having the same position. The raih-oad cut in the ridge south
of Danbury station is through this formation.

Next we cross through Wihnot (Fig. 84). This rock first appears on the
east, between Potter Place and West Andover, standing vertically. Near
the west point of Andover, in Wilmot, the dip of the well characterized
rock is about S. 70° E. At Wilmot centre the stream falls over ledges of
this rock, dipping 50° in the same direction. A mile west, by a saw-mill,
there is a layer of hornblende rock, a great rarity in this formation. With
it are the usual types of this rock, including layers with feldspar crystals
three or four inches in length. These all dip like the last. By C. Rowe's,
a little farther west, there is a magnificent display of these rocks, dip-
ping the same way. Mica schists and porphyritic rocks with a dark base,
having sparingly disseminated crystals of feldspar, occur here. By a small
mill west of the " Gay stand," in the west part of Wilmot, the mixed por-
phyritic and common gneisses dip southerly. By our map this should be
the western limit of the formation, but there is a porphyritic gneiss on the
west town line, adjacent to Springfield. Our observations have shown
the gradual increase of other varieties of rock in passing west from
Wilmot, and therefore we may believe the characteristic feature may be
almost gone, yet the age not change. Special conditions of deposition or
metamorphism may have precluded the formation of the larger crystals in
abundance. Along this section line the outcrops of ledge have been rare
in the region west of the "Gay stand." Porphyritic gneiss is noted also
about a mile east of the Springfield line. These dips recall the "fan-
shaped stratification" spoken of by the older geological writers, perhaps
resolvable into several closely pressed anticlinals and synclinals.

In the south part of New London there are large bands of porphyritic
gneiss interstratified with the gneiss. The ledges on the south edge of
Pleasant pond are abundant. There is a wide contrast agriculturally
between the country of the porphyritic ledges south of Pleasant pond, and
those southerly from New London centre upon the ordinary gneiss, the
latter exhibiting beautiful farms, the former rocky pastures.

Sutton is nearly all underlaid by porphyritic gneiss. Near the north
line, by C. A. Fowler's, the dip is 75° N. 75° W. The main road, through
the hamlets of North Sutton, Sutton Mills, and South Sutton, abounds

GEOLOGY OF THE MERRIMACK DISTRICT. 523

with porphyritic ledges. At the mills the descent is considerable. Be-
tween Kezar and Gile ponds there is an extensive meadow, and also
below Sutton Mills. About South Sutton are steep conical hills, steepest
on their south sides, as seen from the north-east. At the head of Long
pond is a mass of compact flinty rock, dipping 80° N. 25° E., girt by the
porphyritic rock on both sides. On Stevens brook this rock begins at
the town line, and for two miles the ledges are nearly continuous. Sand
obscures the ledges in the northern half of the town, on the road to Wil-
mot Flat from Stevens brook. It was surprising to us to find such a
level road between Warner and Potter Place, through the Stevens Brook
valley, in this mountainous region.

Another route, affording excellent views of this formation, is from
Waterloo station in Warner along the railroad to Newbury summit. At
Waterloo, north of the village, there are many ledges. Next they abound
on the hill by Capt. S. Watson's. The dips may be north-westerly in
them. Other outcrops are at a flag station midway between Waterloo
and Melvin's Mills, and also at the mills. On a ridge south is a bed of
the hard schistose rock usual in this group, standing vertically, with the
strike N. 20° E. Other ledges crop out at Bradford mills, and quite
abundantly along the railroad beyond, through Newbury. The dips on
this route were not recorded. At the summit cut, near the south end of
Sunapee lake, the rocks are finely shown. A dark micaceous porphyritic
gneiss predominates, dipping 50° S. 65° E., and containing very irregular
veins of coarse granite. Sketches of the veins show the mass composed
of a coarse variety, full of beautiful minute garnets, and on both sides,
adjacent to the walls, narrow bands of a finer grained granite. Next the
vein the schists for a few inches' distance are often altered. Just north
of the station the dark rock lacks the crystals of feldspar, retaining the
same position. The formation is supposed to extend along the west
shore of the lake to the north-west Hmit of the town, and also to make
up the mass of Sunapee mountain farther south.

We have the data for a more satisfactory section from Washington to
Contoocookville, across the very widest part of this porphyritic range,
and shown in Fig. 85. The strata dip easterly along the western border
of the rock. In Washington we have first a synclinal, an anticlinal, then
a synclinal again at East Washington. The high hills in the south-west

524 STRATIGRAPHICAL GEOLOGY.

part of Bradford are thought to constitute another anticHnal, the dip of
30° S. 52° E. having been measured by A. Putney's. An anticHnal is put
down for the highlands farther east, and the mica schist between Brad-
ford centre and Bradford pond is reckoned as occupying an inverted axis.
Ledges appear at the height of land, at the Baptist church, and along the
west shore of Bradford pond. The last part of these dip easterly. Next,
there is a considerable area of fine-grained gneiss supposed to belong to a
later age, and occupying a basin in this older group. The east side of
it is reached at Day pond, in the south-west corner of Warner, where
high precipitous ledges of the porphyritic variety occur. Another mica-
ceous schist, dipping 70° E. 80° E., occurs next on the Warner and Hen-
niker line. Farther east, the dip is twenty degrees less. The whole
width of this outlier is about half a mile on the town line, wider to the
south. Next reappear the porphyritic gneisses, continuous to the most
north-eastern school-house in Henniker. The schist on the western bor-
der of the gneiss, east of the porphyritic, dips 75° S. 70° W. Thus this
section also shows the fan-shaped stratification.

The occurrence of a curved line of hills in Washington, Bradford, and
Henniker, is interesting. Lovewell's mountain is the highest and farthest
west ; the others are much elevated, and curve like a bow till the Contoo-
cook river is reached. A trip from Bradford mills to Hillsborough Bridge
showed porphyritic gneiss as far as Bible hill. Ledges were abundant
near E. Cheney's, Bradford centre, and on the high hills in the south part
of Bradford ; and on Murdo hill, at the school-house near Loon pond,
Hillsborough centre, and Peaked hill, in Hillsborough. Other localities of
these rocks in Hillsborough appear at the Johnson place, and at the house
of Miss Gibson, west of the lower village. It outcrops at the head of
Long Falls, on the Contoocook river, dipping possibly 28° N. 52° W ;
about a mile farther north-east, two miles south-east from West Henni-
ker, on the northern slope of a large hill, and at Henniker village, having
the strike of N. 5° E., judging from the course of the longer axis of the
feldspar crystals. The slates on the east dip towards the porphyritic
gneiss.

In Warner, the Mink hills are all composed of this ancient rock. South
of Bald Mink, a ledge of it, not necessarily typical of the mass, dips 20°
W., and carries a vein of hyaline quartz, four feet wide. Ledges are

Plj^t^ XXL

<^ PoRPhYRITIC

J- Gneiss-

M

^ J^ ^-

Fig. 82. Section between Two Main Ranges of Porphyritic Gneiss.

Fig. 83. Section from Fast Enfield to Danbury.

G N E I /S /s.

Fig. 85. Section from Love well Mr. nearly to Bear Pond, Warner.

,< Porphyritic -? Gneiss

^ ! >*^ P^'^O R P H Y R I .v-T I C

GNEISS

Fig 84^. Section IN Wilmot. Fig.SG. Section in Stoddard and Antri

Gj<fN<$'E I V'S S. xO' Mica Schist. (f J J Granite. LAKE GNEISS.!

/ ^T A' ^^ ^(,UNCANOON0cl!A*:E)<(,^^'^00KSETrRANGE^ ^V ^ t

mmmnmnnmimL -^

TlIJJ7TmiJTrnmTTm/ii/!ii::.'^.-xv^'.^^^:mTiTrrrTTrnrVYnTT^

Fig. 87. Section from South Weare to Manchester.

SCA.LE, HORIZONTALLY. 2s MILES TO AN INCH; VtHTICALLY., 3000 FF-tT TO AN INCH.

GEOLOGY OF THE MERRIMACK DISTRICT, 52$

extremely common along the Mink hills, and the country west and south
to the town lines of Bradford and Henniker. The road from the North
branch in Antrim, across Windsor to Washington, shows chiefly ledges
of porphyritic gneiss. The first hill climbed is very steep, and the strata
may dip north-west. After reaching the crest of the hill, ledges are not
abundant, the surface of the country being mostly covered by immense
boulders of the same material, particularly between the southern school-
house and Black pond. It is a characteristic feature of the porphyritic
region that the surface should be conspicuously covered by large boulders
of the same material with the underlying rock. Fertile tracts of land
occur where the covering of drift has been finer than usual, or they have
resulted from the filling up of low grounds. By Black pond in Windsor,
the strata dip south-east. The road through the northern half of Wind-
sor is over a smooth drift ridge, descending to a deep and wide alluvial
peaty flat, below the outlet of White pond. This water flows north-
easterly, tributary to the Contoocook, though not so represented upon
the county map. In the edge of Washington, the profusion of boulders
of porphyritic gneiss recommences, and the ledges appear at school-house
No. 6. Near here are a few ledges of common gneiss, followed very
speedily by the ordinary coarsely crystalline variety, which occurs several
times on the road to Washington centre. Hills to the east, like Kings-
bury, in Washington, and those in the east and north part of Windsor,
seem to have the same underlying rock.

The next section (Fig. 86) extends from Stoddard to North Branch vil-
lage, in Antrim, the strata appearing mostly monoclinal without any anal-
ysis of the dips. As in Washington, farther north, quite ferruginous schists
flank the porphyritic gneiss on the west side, dipping 60° S. E., near Stod-
dard centre. At the mill village are the first porphyritic ledges, dipping
in the same direction. These ledges are magnificently displayed near the
east line of Stoddard. We have not passed directly over Tuttle hill, but
followed the road to the north, down the North Branch valley, where we
observed ledges of this rock at S. Dinsmore's and near the village. Its last
outcrop on the section line is near Campbell pond, on the west side of Mt.
Riley. Between the North Branch and centre villages are several outcrops
of this rock seeming to dip N. W. The gneisses of Mt. Riley dip easterly,
and therefore we represent a dip of the porphyritic variety conformable

526 STRATIGRAPHICAL GEOLOGY.

with it, thus necessitating the supposition of an antichnal east of the north-
ern village. The east part of the town of Antrim is occupied by a later
gneiss, supposed to be encircled by the coarser rock, and to be that which
crops out at first north of South Antrim and continues to Bennington, on
the west side of the Contoocook. At Bennington the strata are about
vertical, and the strike runs north-east and south-west. The rock at the
mills in the village is well characterized. Hancock is entirely underlaid
by porphyritic gneiss, and the whole breadth of the formation is repre-
sented by the town limits. To the south it narrows rapidly. A trip up
Nubanusit river, into the east part of Dublin, showed only drift ; but near
the north-west corner of Peterborough there is a hard rock associated
with porphyritic gneiss, dipping N. 50° W. The ledges were seen at
intervals for two miles parallel with the north town line.

There is a spur of the porphyritic gneiss running from Peterborough
into Greenfield and Francestown. An enormous boulder of it first
attracts notice at J. Miller's, near the Greenfield line, — no ledges appear-
ing from Peterborough village till we come to A. Green's. The country
is flat, and covered with glacial drift much of the way, with a very few
rocky outcrops. In Francestown the eastern limit of the porphyritic is
reached near S. Duland's, the ferruginous seams there indicating a posi-
tion of 50° N. 85° W. It is noticeable that this branch points towards
the large porphyritic area in Weare, and an axial line is probably indi-
cated by this circumstance. The areas of this rock farther south, in
Jaffrey and Fitzwilliam, have been noticed in the previous chapter.

Upon Plate I there is a small area of this rock represented in Massa-
chusetts, occupying the natural extension of the main New Hampshire
range. The observations were taken from the Massachusetts report,
where we find both our northern ranges noticed. The more western one
shows itself in Northfield. The more eastern is said to be situated imme-
diately east of a range of hornblende slate, which is made to extend from
the Connecticut line at Monson directly north to Royalston. It will be
noticed that Royalston adjoins Fitzwilliam; so that the connection
between the Massachusetts and New Hampshire main ranges of this
ancient rock is clear, and the general north and south course of the range
is also continuous. My father thinks a strip of it may be found extend-
ing as far south as Long Island sound. He speaks of the fine develop-

GEOLOGY OF THE MERRIMACK DISTRICT. 52/

ment of this rock in the high hill east of Ware Village, extending south-
erly through Palmer. Those who ride over the Boston & Albany Railroad
cannot have failed to notice this rock in Brookfield and Palmer. My
father did not distinguish this formation upon the map, as he did not
attempt to subdivide the gneiss, but has furnished data which enable his
successors to trace out the formation.* The recognition of this porphy-
ritic rock outside of the New Hampshire limits is of great importance,
and it may furnish a clue to the structure of our New England geology.

Some observations of a trip through Winchendon and Royalston will
further illustrate our position. Rindge has just been left, with its uni-
form ferruginous aspect. One mile west of Springville, in Winchendon,
we observe the same rock in a horizontal position. One mile west of
Winchendon the same rock, with coarse granite beds, dips 35° N. W.
On reaching New Boston, a small hamlet in the south-west part of the
town, ledges of porphyritic gneiss are perceived dipping west. A massive
even-bedded variety succeeds, followed by the porphyritic, before coming
to the village of South Royalston, dipping 85° west. This ancient band
is nearly three, and perhaps five miles wide, cropping out in the direct
line of continuity from the main backbone range of New Hampshire. On
the west of South Royalston a gneiss like that of Winnipiseogee appears,
dipping west, and within three miles the dip is reversed, giving us a syn-
clinal axis. At Athol the rock is like the Montalban series, and dijDS
westerly. The Lake gneiss comes up again in the New Salem, Shutes-
bury, and Pelham hills, with westerly dips. These may represent the
southward continuation of the older rocks of the western part of Cheshire
county. There is therefore a correspondence between the order of the
formations in southern New Hampshire and northern Massachusetts,
through Worcester and Franklin counties.

The Smaller Ranges. I will speak first of those about Warner. Bean's
Hill, near Union church, in the south part of Salisbury, furnishes the
beginning of an area of this rock a little over three miles in length.
Tucker pond, Salisbury, and Bagley pond, Warner, with the west branch
of Schodac brook, are situated upon it. The land stands out by itself,
to some extent. There are three minor elevations upon it in Salisbury,
and one in the very north-east corner of Warner. I do not find observa-

* Final Report Geology, Mass., p. 628.

528 STRATIGRAPHICAL GEOLOGY.

tions of the position recorded. On the main Schodac branch, where it
crosses the Warner Hne, is a smaller area, about a mile long. It is bound-
ed on both sides by ferruginous schists. Near Davisville is a third area,
considerably smaller than the last, having an andalusite schist joining it
on the west. All these areas are isolated from all connection with each
other, or with the longer range to the east in the Blackwater valley.
The smaller areas have a north-east course, the larger runs east of north,
and all of them differ in direction from the Blackwater range, which
courses a little west of north. They are separated by the Lake gneiss.

This Blackwater range begins near Webster post-office, and runs east
of south, crossing the river in a band by a saw-mill and other buildings
midway between the post-office and the south town line. It then con-
tinues in a high narrow ridge to the north part of Hopkinton, a distance
of four miles, where it is covered up by the sand of the three converging
rivers, — the Blackwater, Warner, and Contoocook.

This range is discernible in Hopkinton. It first crops out on the hill
south of Tyler's station, on the C. & C. Railroad, with the dip 70° N. ds''
E. There may be some veins of it cutting the adjacent ferruginous rock.
Next is an outcrop of limited dimensions, a short distance north-westerly
from the village of Hopkinton. These ranges point to the north end of
the Weare area, in the south part of the town. Near J. & J., and E. G.
Quimby's, we have porphyritic and common gneiss and mica schist, dip-
ping 32° N. 85° W., with six feet width of white quartz. There are sev-
eral exposures of porphyritic gneiss along the east and west road and the
north part of Weare. South of J. Edmunds's the base rock holding the
crystals is a clear, dark-colored, fine-grained mass. On two west roads
farther south are other exposures. Near East Weare this rock dips 20°
west. In the western part of this area, by D. D. Rowe's and S. S. Clark's,
the dip is 20° S. 48° W. A little nearer North Weare it dips more west-
erly, and is succeeded by an overlying granitic gneiss with a small dip.
This area is three and a half miles in its greatest diameter, and nearly as
wide. The dips are all in the same general westerly direction, so that it
must be an inverted anticlinal in its structure. A comparison of the
trends of outcrops tends to the theory that the Greenfield spur from the
main range may be continued in the North Weare, Hopkinton, and Web-
ster areas.

GEOLOGY OF THE MERRIMACK DISTRICT, 529

In the south part of Weare, about a mile north-west of Oil Mill Village,
is a small area of this rock, dipping 45° N. 50 W. Passing south-westerly
into New Boston the same range crops out at J. E. Woodbury's, near the
Weare line, with a north-westerly dip, and near Still pond, dipping 75° N.
60° W. The last has ordinary gneiss layers interstratified with it. These
three localities are obviously connected, and constitute an ancient ridge
parallel to the one previously mentioned.

There is an outcrop of limited extent east of the Merrimack river in
Concord, near the " Mountain farm." The twin structure of the feldspar
crystals is more obvious here than at any other known locality. The dip
is north-westerly. It is associated with a rock like Concord granite, and a
small trap dike is contiguous. I judge this outcrop to be unlike any of
the others that have been noticed, and, if of the same age, belonging to a
different or parallel range. It is quite near a quartz band, of which more
will be said eventually.

The amount of the porphyritic gneiss in Pelham is not definitely
known. When crossing the town on the line of Section I, I found in the
valley, from one to two miles west of Pelham village, near J. Gage's,
ledges of a porphyritic gneiss, but did not preserve a memorandum of the
dip. It probably dips southerly. There is a record, also, of a single ledge
of this nature by the high bridge over the Souhegan river, near the north
hne of Greenville. The dip of the associated rocks is 15° N. W, There
is another a mile west of Pratt pond. Large blocks of this gneiss occur
frequently in the valley of the Souhegan farther north, which may possibly
have been derived from the neighborhood.

ConcliLsions. The facts stated thus far about the porphyritic gneiss
authorize the following conclusions :

I. The central ridge has been subjected to such powerful pressure that
both sides have been inverted frequently, and we observe the fan-shaped
variety of stratification. A hasty generalization might state that this was
the newest instead of the oldest formation in the state, because newer
rocks apparently dip beneath it upon both sides. The same questions are
raised here that have been discussed for many years in respect to the
structure of the Alps in Switzerland. This main New Hampshire range
may have formed a high mountain chain in past geological time, the more
elevated summits having been eroded to furnish material for the building

VOL. II. 6"]

530 STRATIGRAPHICAL GEOLOGY.

up of the adjoining Lake and Montalban schists. We find here no
examples of the modern type of syncHnal mountains comparable with
the Catskills or Greylock, since all such have been removed entirely by
denudation. The ascent to the highest topographical line here is gradual
from all sides, — something of the ge-anticlinal structure as set forth by
Dana. From this elevated surface there is an occasional remnant of a
later superimposed formation, like Monadnock and Kearsarge mountains.
These features indicate a greater antiquity to the height of land in New
Hampshire than belongs to the Green Mountains of Vermont. The
latter still exhibit the anticlinal build. Should they be compressed still
more, so as to produce inversions on both sides, and have their summits
levelled down to the general average height of the mass, they would then
be like the older New Hampshire range.

2. The repetition of the porphyritic gneiss in the smaller areas, and
the occurrence of limited basins of gneiss and schist upon it, indicate the
presence of anticlinal and synclinal lines, and thus aid in unravelling
the stratigraphical features of the state. First of all, there is what might
be called the Pemigewasset basin, a depression between the main range
and that along Squam and Winnipiseogee lakes, allowing the accumulation
of the Montalban series. Next, the Pelham area may be a remnant of
an ancient ridge of this rock to constitute, with the main range, a basin
for the deposition of the gneisses and schists of the lower Merrimack
region. Third, smaller lines of upheaval or demarkation of basins are
more clearly defined about the well established area ; e. g., there is the
Peterborough and Greenville branch, continuous in the Weare, Hopkinton,
and Webster outcrops. This gives us a basin for the deposition of the
rocks between Greenfield and Salisbury. A smaller basin is that enclosed
by the three Schodac areas of Warner, with the main mass in the Mink
hills and Sutton. The gneiss outside of the Greenfield and Webster fine
is divided into two parts by the New Boston and South Weare line.
There are two very obvious depressions in the porphyritic gneiss, about
Bradford pond and in the west part of Hcnniker. Others must occur in
the very large area between Wilton and Dublin, which farther explorations
will bring to light. The depressions for the Monadnock and Kearsarge
series must have been more extensive than any that have been mentioned.
These lie partly upon this ancient formation, but as they involve others

GEOLOGY CF THE MERRIMACK DISTRICT. 53 1

of later origin, notice of their limits must be deferred. Opportunity may-
be afforded for the perfection of our general sections before the final
completion of our explorations, in which case the reader will find in the
atlas further details of structure in this ancient formation than appear
from our descriptions.

We have not yet identified the Bethlehem gneiss in the eastern part
of the Merrimack district. In the western part of the district three areas
of a fine-grained variety are separated from the more characteristic rock,
and delineated upon the map ; and it is likely this kind of material, if not
the other, might be found east of the porphyritic ridge. This distinction
was made after the conclusion of all field work, so that it has not been
practicable, as yet, to apply it to the eastern region. There is also a
scarcity of hornblende in the Merrimack valley, the rock made use of in
the Connecticut valley to mark the limits of the Bethlehem areas.

2. Lake Gneiss.

These rocks occupy about the same territorial area as the main porphy-
ritic range just described. There are three principal lines of its occur-
rence, divided into many subordinate or isolated areas, which have been
separated on account of concealment by overlying later formations. We
find, first, the Northfield and Antrim line ; second, the Dunbarton and
Peterborough, — areas separated widely by a subsequent covering of rock,
but connected directly with the next by an axial line ; third, the Deerfield
and Mason line ; fourth, the Hampstead and Pelham. I will notice each
of these in order.

NortJifield and Antrim Range. The north-east end of this range is
in several parts, or isolated areas, in S?,nbornton, Tilton, and North-
field. West of Merrimack river, the principal exposure upon this first
line is met with, occupying a large part of Salisbury, Webster, and
Warner, and small portions of Boscawen, Sutton, Hopkinton, and Hen-
niker. Next comes an area occupying the Contoocook valley in Hills-
borough, Deering, and Antrim. Outliers on a parallel north-east line are
in Francestown and Deering, having the Greenfield-Weare-Hopkinton
porphyritic ridge for its eastern boundary. On the west side are the two
outliers upon the porphyritic gneiss in Bradford, Warner, and Henniker.
This line of outcrops is forty-one miles in length, and twelve in its great-

532 STRATIGRAPHICAL GEOLOGY,

est breadth. The most north-eastern of these areas in Sanbornton is five
miles distant from the southern end of the typical district of this rock in
Meredith. On the west side of Cawley's pond are many outcrops of
gneiss. A little north are three embossed ledges, dipping north-east, and
farther north they dip north-west. There is a hill of granitic rock, the
highest land in the north-east part of the town, where the dip is north-
westerly. The rock has been quarried for underpinning to a slight
extent near O. Eastman's. It is not easy to say this does not belong to
the mica schist series, particularly since granitic beds are found in the
neighborhood, such as belong to the later series. I have specimens of
gneiss from D. P. Tucker's, a mile north of Tilton village, with a north-
west dip. At Tilton village the Montalban strata dip high to the south-
east, and another exposure of gneiss occurs near C. Emerson's, in the
north corner of the town, next New Hampton.

In Northfield, near D. M. Howard's, about a mile from Tilton, granitic
gneiss dips 30° N. 65° W. Towards T. E. Poor's the ledges have the
segregated aspect so commonly, seen about Lake Winnipiseogee, and the
dip is higher. There is gneiss, also, about the village of Northfield centre,
but our information concerning this area is meagre.

The shape of the Salisbury area indicates the presence of an anticlinal
in the eastern portion, as the newer Montalban schists wedge into it from
the south along the valley of Mill brook, and from the north include Salis-
bury centre. The Montalban rocks of Franklin dip north-west to their
very end, crowding closely upon these compact gneisses standing verti-
cally and with a strike west of north along a line of hills near the east
town line of Salisbury. The contrast between the two formations is well
marked, and their relative positions indicate an unconformity between
them. These hills are unnamed on the map, and are a mile and a half
east of South Salisbury. At the village the rocks are more like the
Montalban, and perhaps this eastern range should be isolated from con-
nection with the gneisses west of the village, at H. Heath's and A. Ward-
well's. These gneisses occur for two miles south of South Salisbury, on
the road to Boscawen, with north-westerly dips. Ledges appear at the
town line, and at C. Smith's in Boscawen. The ridge a mile and a half
north of Corser hill, separating the Blackwater from its tributary through
Great pond, is composed of this gneiss. South of Corser hill, outcrops

GEOLOGY OF THE MERRIMACK DISTRICT. .533

appear at Mrs, M. French's, E. Little's, etc., but it is not easy to obtain
satisfactory dip observations. Farther south, as at E. Shepard's in Web-
ster, the strike is well defined, running S. 20° E., the strata being vertical.
These are repeated by J. and Capt. I. Allen's, nearly a mile farther south.
Other observations enable us to color this rock as a narrow strip east of
the porphyritic ridge as far south as Hopkinton. In Boscawen village
there is a gneiss, possibly of this age, dipping 60° E. It resembles the
Concord granite, and lies at the north end of the village. There are
many ledges of this gneiss in the Blackwater valley at North Salisbury,
at the lower end of the bay. Others occur farther south, north of J.
Wiley's, and at his house. The area makes a notch in the porphyritic
rock in the south-west part of the town. Along the Blackwater valley
many ledges are obscured by alluvium, and we have not had the oppor-
tunity to travel along the two long stretches of nearly parallel east and
west roads in Salisbury. In Webster, and north of Long pond, the pecu-
liar features of the Lake gneiss are clearly recognizable in its granitic
aspect and the traversing by numerous segregated veins. Ledges are
noted at the north end of the porphyritic ledge dipping S. 20° E. ; at the
mills by the crossing to Corser hill from the west ; at the top of the hill
west, overlooking Long pond, where are large veins of quartz ; north of
this pond ; and by the water's edge, where several houses occur near
together. In most of these cases the dip is obscure. At the last-named
locaHty the strike is N. 30° E, The long hill south-west from Long pond
shows many ledges resembling this formation as seen from the valley
west.

In Warner observations are more abundant and satisfactory. West of
the Long pond exposures in Webster we find the schists to the town line
considerably ferruginous before coming to the isolated porphyritic area,
and also west of Mud pond in Warner. Compact gneiss is abundant from
this porphyritic outlier southerly as far as the alluvium of Warner river.
Back of the school-house the layers are ferruginous, — less so at T. H.
Bartlett's. The gneiss is of the normal variety at S. Bartlett's, on top of
the high hill west of Schodac brook. Most of this hill is composed of
drift. Between J. C. F'landers's and the lower Warner village granitic
gneiss occurs with diverse dips, at first to the north-west, and near the
village 80° S. E. Between the two villages the dip is 80° N. 20° E. A

534 STRATIGRAPHICAL GEOLOGY.

mile north-east from the centre the gneiss shows itself at the crossing of
Willow brook. Other ledges occur on the hill west of Bagley pond, as at
J. L. Mason's, dipping north-west at a small angle. Willow brook flows
for more than a mile through swampy land in the north part of the town.
On taking the road to Mt. Kearsarge, from Warner, we find gneiss at the
point of starting, with a north-westerly dip. On top of the first consider-
able hill, at S. C. Pattee's, the compact gneiss dips 80° N. 30° W. There
is more of this rock at the south-west corner of Salisbury, and at the
crossing of French brook, near J. George's. This is the northern limit of
the formation. It is succeeded by vertical masses of andalusite schists,
with strike N. 30° E. Sawyer's hill and the south-west part of Salisbury
are supposed to be underlaid by this same gneiss. The last mile of Ste-
vens brook, in Warner, shows the same rock, more especially between
the tributaries called French and Meadow brooks. There is a ledge at
the Sutton line, also, which adjoins the porphyritic gneiss. Between
French brook and the village of Warner the rocks are concealed by
coarse alluvial and drift deposits, which are very extensive. Taking the
road towards Bald Mink we first see gneiss with a north-westerly dip close
to the river, then 70° N. 52° W., near E. W. Sargent's. The same rock
continues to the height of land south of Bald Mink. Others are to be
found constituting two hills, — one having three Davis houses upon it, and
the other west of G. Foster's. The next is a little west of Levi Bartlett's.
Others, perhaps the most south-eastern in this area, occur in " Joppa," be-
tween the school-houses, with a south-east dip. The rock is a mica schist,
and at W. Danforth's there is a small bed of limestone associated with it.
It is probable mica schists intervene between Danforth's and the locality
of limestone west of Pleasant pond. The latter bed is associated with
quartz, and has been burned once for the manufacture of quick-lime.
The bed is twelve feet wide. The rock adjacent is a mica schist, dipping
70° S. 70° E. West of Tom pond, in Davisville, is a gneiss much like the
Concord granite. These schists, with the quartz and limestone, will be
represented upon the map as Montalban. Well defined gneisses often
make their appearance on the hills on the south-west side of the railroad,
between Davisville and Warner lower village.

The conclusion as to structure derived from these observations is the
existence of an anticlinal line from the Bagley pond area of porphyritic

GEOLOGY OF THE MERRIMACK DISTRICT. 535

gneiss across to the north-east point of the same kind of rock west of
Bear pond. There are probably two similar axial lines in Salisbury.

Little is known of the area put down for Amy brook, Henniker, and
extending into the edge of Warner. It may possibly belong to the ferru-
ginous schist deposit. The rock is like the siliceous layers occasionally
associated with the porphyritic gneiss.

The Bradford pond area distinctly belongs to this Lake formation. It
extends into Warner, where the stone has been quarried, as it splits read-
ily into long slabs suitable for underpinning and pillars. It is believed to
dip north-west at its east border by Day pond. It crops out along the
west side of Bradford pond. The rock also occurs in enormous boulders
over this area, and the dips are obscure. At the outlet of the pond the
dip is 50° N. 26° W.

The Hillsborough area may commence two or three miles below the
bridge, the land being free from ledges in the valley. The village at the
end of the railroad occupies a ridge of glacial drift that has been thrown
across the valley in ancient times, producing a lake which by filling up
gave rise to the long flat meadow land above. The ledges at the upper
dam consist of gneiss and coarse granite, dipping N. 40° W, On the east
side of the river a rough gneiss dips 80° N. 80° W.

About two miles into Deering, by H. Preston's, is a small ledge of a
hard variety of the Lake gneiss, which constitutes the eastern limit of the
formation. On the line of Section III, about three miles from the bridge
in Deering, is a gneiss of similar character. The dip is uncertain. It
should be westerly if like the same strata farther north, but easterly if it
agrees with the schists overlying it. The latter is the probable dip, thus
giving us an anticlinal axis in the Contoocook valley. The rock is sup-
posed to extend south-westerly to pass into the known outcrops of similar
rock between Antrim centre and Clinton village. Just south of the latter
hamlet the rock is a hard, dark-colored, crystalline gneiss, such as is charac-
teristic of the Lake group farther north. This Hillsborough area is very
much like the well-defined one already noticed in Bradford, only larger,
being nine and a half miles in length instead of three and three quarters,

I think it well to regard the three isolated patches in Francestown,
Deering, and North Weare as continuous, constituting a range ten miles
long. On the north-east the gneiss has been observed in a precipitous

536 STRATIGRAPHICAL GEOLOGY.

cliff, facing westward, nearly three miles west of North Weare station, and
near the union of Dudley brook with a large tributary from the north-
west. Half a mile south from the cliff is a gneiss of this age, yellowish
from superficial oxidation of iron, having the strike N. 23° E., and a
vertical position. Other ledges occur a mile west, and at the town line
between Weare and Deering the dip is 85° N. 75° W. The next gneisses
crop out at J. Downing's, and in the brook to the east of his house, south-
east from Deering centre, and are thought to dip westerly. At D. Gregg's,
two miles south of Deering, is the unmistakable gneiss of the Lake
group, dipping 85° N. 70° W. This is upon a hill. The rock may not
be more than a mile in width. Ledges are rare in this neighborhood,
because of the extensive development of the lenticular hills of drift, to be
described fully hereafter.

Next we have the larger portion of this area in Crotched mountain, in
Francestown. I have not ascended the summit of this peak, but on the
north and south sides ledges of Lake gneiss occur, which make it proba-
ble that the mountain is composed of the same. The large boulders on
the south side of the mountain are also of the same character, as would
be the case if our view is correct. About a mile and a half west of
Francestown village are the first known ledges of this rock, and they
occur through the township on the old turnpike leading to Hillsborough.
Near the town line the strata dip 80° N. 60° W. There are no ledges
exposed along the road on the south side of Crotched mountain, only
enormous boulders. The first rocks seen to the south-west of this moun-
tain are the overlying ferruginous schists, and the range just described is
therefore terminated.

The Dunbarton-Pctcrborotigh Range. The next line of elevation is less
extensive. Nothing is seen of it, — that is, of this rock, — beyond the Dun-
barton elevation. It will be noticed that the five hundred feet contour
line almost isolates Dunbarton, and that the rock is largely the Lake
gneiss at the north-east end of this range. Moraines cover the low neck
of land connecting the Dunbarton island with Hopkinton, so that the
north-western limits of this rock are not fully known. To the north-east
it is easily confounded with the Concord granite. I think it well to say
that the latter stop with the south-west end of Great Turkey pond, and
hence the similar rock in the very south-west corner of Concord may

GEOLOGY O-^ THE MERRIMACK DISTRICT, 537

be regarded as the first ledge of the Lake gneiss. It is near a saw-mill,
and dips south-east. The next known ledge is at J. Heath's, in the north-
west corner of Dunbarton, the north-west part of Bow being concealed
by river deposits. The rock is white and slaty, dipping from 55°-6o° N.
55°-8o° W., opposite to the other position. There are several of these
ledges between Paige's corner, or North Dunbarton, and Dunbarton cen-
tre. At H. Jameson's, not far from the west line of the town, opposite
East Weare, and on the brow of the hill, the gneiss dips 50° N. 60° W.
At a school-house nearly a mile east, on another road, the dip is essentially
the same, or ten degrees less. An abundance of drift covers the ledge at
the village, and a mile and a half to the south the Montalban rocks suc-
ceed. A narrow strip of territory in the east part of Weare is included
in this part of the gneiss. The porphyritic gneiss has the shape of a
wedge, and makes, as it were, a notch in the edge of the granitic variety,
another spur running out from East to North Weare. On the south side
of the North Branch, at East Weare, the gneiss dips 20° W. Other ledges
occur farther south, and notice has already been taken of the gentle north-
west dip of this rock a mile north-east of the village. The western edge of
this spur comes within a mile of Clinton Grove. The same rocks occur
in several places at the north base of Mt. William, in following the road
around to East Weare. Mts. William and Wallingford are composed of
mica schist, which take another piece out of this Lake area, only this is by
covering the other formation instead of eliminating it, as was the case
before. The south part of Weare shows the Lake gneiss as characteris-
tially as its typical locality on Winnipiseogee. Two miles south of Mt. Wil-
liam pond, by H. S. Hoyt's, the gneiss dips 80° N. 20° W. Next the por-
phyritic range in the south-east corner of the town the dip is 45° N. 50°
W. The most western outcrop is about a mile and a half south-east of
M. A. Hodgdon's, at the east base of Mt. Misery and Odiorne hill. Other
outcrops are near J. G. Dearborn's and at the village of South Weare, by
a school-house. West of A. H. Buxton's and a school-house the dip is
80° N. W. Near J. Sargent's the dip is 70° N. 80° W. At A. W. Cilley's,
near the south line, is the most western ledge noted, dipping northerly
and north-west. At the town farm the dip is 50° N. W. In New Boston
there is a fine exposure at G. Cram's. This formation does not occupy
quite the whole of the township of New Boston to the north-west of the
VOL. II. 68

538 STRATIGRAPHICAL GEOLOGY.

porphyritic range, as the ferruginous schists appear at the extreme corner.
Possibly the gneiss may just enter the eastern Hmits of Francestown, near
Haunted pond.

The gneiss of Peterborough is beUeved to be an extension of the Dun-
barton and New Boston ledges, although isolated, because it lies close to
the Greenfield branch of the porphyritic gneiss, which has been regarded
as on the same axial line with that in the north part of Weare. The
dimensions of this area are correctly given on the map, but little is known
of the dips. By Mrs. Chapman's and J. Smith's, near the south town line,
the dip is westerly. Gneissic strata appear in Peterborough village,
near the mouth of Nubanusit river, standing vertically, and as far as W,
French's, a mile and a half north, also a mile to the north-west. East of
the Contoocook the gneiss is extensively quarried for underpinning, and
is an excellent material for that purpose. The dip is 80° N. 72° E. The
same rock extends south-westerly towards Jaffrey. These observations
indicate a synclinal structure to this area, but are too meagre to enable
us to assert that no other axes exist, as that is of great consequence.
The west side of the basin, or that nearest the porphyritic gneiss, is the
steepest, as might be expected from its proximity to the older formation.
Perhaps the north end of the gneiss area in Royalston, Mass., seen on the
map, may be the continuation of this other Antrim range.

The Manchester Range. This is the most important of all the areas of
this rock in the state, because it is traversed by two parallel bands of
quartz, certainly thirty-three miles in length in this district, and probably
over eighty in all between the remotest points of occurrence. The area
may be naturally divided into two parts, — first, that enclosed by the two
bands of quartz ; second, that lying to the south-east of them. With the
first may be included an inconsiderable portion to the north-west, lying
south-east of the anticlinal line indicated by the long narrow band of por-
phyritic gneiss in New Boston and Weare. Perhaps, however, it will be
best to describe, first, the courses of the two bands of quartz. We may
distinguish them by the names of the towns where the bands respectively
cross the Merrimack river, or Hooksett and Manchester. Their general
course is north-cast and south-west, and of course the Hooksett range
lies to the north-west of that denominated Manchester. The history of
their exploration and certain facts concerning their distinction were first

GEOLOGY OF THE MERRIMACK DISTRICT. 539

given in our Report of Progress for 1872, and in Vol. I, pages 49-51, of
this work. The material of this rock is usually a stratified white quartz,
varying somewhat in color according to local circumstances. Wherever
it bends, and at other parts of its course, it is penetrated by an immense
number of veins of a whiter or more milky quartz, insomuch that these
veins often constitute the principal part of the rock. The whole bed may
have been deposited from thermal waters ; but we do not yet discover evi-
dence that the original stratified siliceous material occupied a previously
existing fissure. The beds we regard as conforming with the stratification,
and as guides in the study of the structure of our rocks.

The Hooksctt Range of Quartz. Leaving out of view the bed in the
south part of Pittsfield, as that may be either Montalban or Rockingham,
we find first of all, on the north-east side, ledges of this rock in Aliens-
town, in the narrow neck of land between the Suncook river and Hook-
sett. Next, in Hooksett, between Lakin's pond and a road turning
south-westerly towards the village, are exposures about forty rods long.
I think there is another ledge between this and the river. The railroad
bridge of the Concord & Portsmouth Railroad, at Hooksett, rests upon
ledges of this rock, the two islands consisting of quartz dipping north-
west. Next we find it prominently in the Pinnacle, a conical, isolated
peak, perhaps three hundred and fifty feet above the river. There is a
pretty pond on the west side of it, A little to the south-west, perhaps a
mile from the bridge spoken of, is a vein of metalliferous quartz carrying
galena. The stratified quartz dips 50° N. W. From the Pinnacle one
can look to Hackett's or Whittemore's hill, in the west corner of the
town, in a south-west direction, the next conspicuous hill of quartz on
this range. The outcrops are numerous between the lead mine and
Whittemore's hill, all having essentially the same position, but not so
great a width. There is a high hill of it, covered with trees, back of S.
Bachelder's. My impression is that the widest part is not over two
hundred and fifty feet in breadth. I did not see any outcrop of this
quartz along the line of Section HI. It should appear near W. A.
Hackett's, near the west town line. The dip of the rocks here is to
the north-west, and judging from the position of the strata along the
section line, there is a possibility that the quartz may reappear, dipping
south-east, in the east part of Bow. South-west from Hackett's the

540 STRATIGRAPHICAL GEOLOGY.

country rises gradually into a ridge, culminating at Whittemore's, between
seven hundred and eight hundred feet above the sea. The dip is high
north-west here, and there have been excavations in search of gold. The
west border of it is calcareous. To the south-west, and west of J.
Cheney's, in the edge of Goffstown, is a high peak that has not been
visited, but is surely made of this rock. North of M. W. Woodbury's,
upon Black brook, the quartz is fully displayed, dipping north-west usually,
but having a strike west of north for a short distance. For more than a
mile the country is away from roads, and the condition of the rocks can-
not be reported upon, but the quartz comes out on the next road, near E,
Jones's, on the west side. Next to the south-west our line crosses the
lower land of Harry brook, and the rock crops out just on the east side.
On the next northerly running road, near D. Kidder's, are outcrops upon
both sides of the road. No other outcrops are reported for three miles,
when it is seen along the railroad, a quarter of a mile south-east from
Oil Mill station, dipping 70° N. 25° W. A hard schist overlies it, and
there is a nondescript sort of gneiss beneath. The band may not be over
fifty feet wide. It next appears between the Piscataquog river and south
of Mrs. Morse's, in the north-east corner of New Boston. We failed to
find it on the two roads next crossing the line, but it appears between a
school-house and Miss Beard's, about three miles to the south-west of
Oil Mill Village. The line must curve a little more south-westerly, but
being somewhat back from roads, and the country covered by lenticular
drift hills, no satisfactory outcrop is reached till we arrive at P. Dodge's,
a mile and a half north-west of New Boston village. Near J. H. and L.
Richards's is a small drift hill chiefly composed of angular fragments of this
rock, so that its place cannot be far distant. At Dodge's the dip is 80° N.
80° W., and the band is not more than thirty feet thick. There is a possi-
ble exposure of the quartz west of L. Dodge's, two miles south-west of
the village. Here we lose sight of this rock. Diligent search has been
made all through New Boston and the adjacent towns, but nothing can
be discovered short of a hill east of J. Haggett's, in the east part of
Lyndeborough, probably with the usual north-west dip of the neighbor-
hood. The distance between these exposures is five miles, and the direc-
tion S. is"" W. There is said to be a little quartz by a saw-mill a quarter
of a mile north of the natural place for the line of outcrop to cross

GEOLOGY OF THE MERRIMACK DISTRICT. 54I

the stream, but the rock appears near E. N. Patch's. Irregularities in
direction are to be expected in Lyndeborough, since the trend of the
rock at Patch's if continued, would carry the ledge a mile below its next
outcrop, west of J. F. Holt's. It continues south of west, and makes
the hill near the glass works at South Lyndeborough, The range runs
S. 55° W., near the village, and dips 50° S. 35° E. The first railroad cut
west of the station barely touches this bed of quartz dipping 75° S. 40° E.
By the eye this range can be followed over the large hill east of Burton
pond, on the town line between Lyndeborough and Wilton. I am not
certain of the occurrence of this rock in the north-west corner of Wilton,
but it may be seen just in the edge of Temple, between A. H. Fry's and
J. Kendall's. On the other side of Kendall's is one of the finest develop-
ments known anywhere along the range. It is from four hundred to five
hundred feet wide. The strike is about N. 30° E. It may be traced
continuously from Kendall's to near Temple village. The dip is probably
north-westerly. The rocks adjacent dip in that direction, and the only
observation I have of the position near Temple is that it is doubtful.
About two miles west of Temple village is a small quartz outcrop, west
of N. Holt's, dipping N. 50° W. into a hill. There is a valley running
west from this point, or rather a notch between Temple and Kidder
mountains leading to Sharon. I have searched diligently all through
this gorge, the mountains upon both sides, and the whole of the adjacent
townships of Sharon and New Ipswich, and am unable to find any
further traces of the Hooksett band of quartzite. Whether it is con-
cealed by the material composing Temple or Barrett mountain, seeing
that it overlies the gneiss formation, whether some enormous disloca-
tion has put it far to one side, whether the formation has pinched out,
or whether some other theory may be devised to explain its absence, is
at present unknown.

The Manchester Range of Quarts. The first well-developed outcrop
of this range, at its north-east extremity, is in the south-west corner of
Allenstown, at J. Hall's. We find a high hill, at the comers of Hooksett,
Allenstown, and Candia, the existence of which may be due to its being
composed of this refractory material. The ledge is clearly traceable from
T. J. Gate's to J. Clark's, or nearly to Moody pond, with the dip north-west.
The surface at Gate's has been beautifully smoothed and polished by the

542 STRATIGRAPHICAL GEOLOGY.

passage of the glacial sheet. Two miles from Moody pond is an excel-
lent exposure of this quartz upon Campbell hill, dipping about 65° N. W.
The rock here partially resembles buhr-stone, being of a grayish color,
and filled with numerous reticulated veins of white quartz. The ledges
extend perhaps half a mile, and are then covered up by the sand plains
bordering the Merrimack river. The same cause prevents a view of the
white bosses on the west side for about two miles. As there is a curva-
ture in the river, causing the water to flow in the same direction with the
trend of the strata, more of the rock is concealed than would be the case
ordinarily at a valley crossing. The quartz shows itself first at G. Kim-
ball's, in Manchester, A high terrace conceals it back from the house,
and it has been noticed next on the hill west, on the road east of Black
brook, and close by the west line of the town, dipping north-west. A mile
farther to the south-west it may be seen at E. Dow's, in Goffstown, after a
long stretch of sand. On the south-west side of the Piscataquog river
the place of the quartz is near J. Black's. Another ledge is near a saw-
mill, a mile to the south-west; and the same is true of another mill
about the same distance beyond in the same direction. Next succeeds
a long interval away from roads, which has not been traversed. After
reaching the roads in the north part of Bedford the quartz is not seen
till we approach the Amherst line, at E. C. French's, and at another
place still nearer the boundary. In the very north-east corner of Am-
herst is a well known locality of hard siliceous limestone, carrying gar-
nets, idocrase, and other interesting minerals, immediately overlying
quartz, all dipping N. 50° W. Three other outcrops show themselves in
the course of a mile. After that, partly on account of the presence of a
great amount of drift, the rock is traceable with difficulty, and it seems
to pass more southerly. At the crossing of the south tributary of Ba-
boosic pond, in the middle of the town east and west, is a large pile of
quartz blocks, too numerous to have been transported by drift. Less
than a mile north of the village is a narrow band of the quartz, twenty-
five feet wide, on the west of the two roads leading to Manchester.
The strike is N. 20° E., the dip vertical. At W. A. Mack's, just against
the most south-eastern corner of Mont Vernon, there is an unusual
quantity of quartz boulders.

We find now the same state of things which has been noticed between

GEOLOGY OF THE MERRIMACK DISTRICT. 543

New Boston and Lyndeborough on the Hooksett range, in the absence
of continuity in the rock, and its recurrence five miles distant on a differ-
ent line of exposure. It appears next on the south side of the Souhegan
river in Milford, back of the school-house situated upon a triangular
area produced by the intersection of roads. The course from the last
locality of the quartz vein in Amherst to this new exposure is S. 65° W.
The quartz dips 75° N. 70° W. It is more gray than usual, almost
passing into gneiss, and very abundantly traversed by reticulating veins
of milky-white quartz. It occupies a hill, and may be followed as a ridge
for about two miles. At B. Gray's, just within the town of Wilton, the
quartz dips 80° N. Tj° W. Other exposures occur in the south-east
corner of Wilton. The last ledge of this range that has been found is
situated near I. A. Brown's, in the north-east corner of Mason, with the
strike N. 15° E., and dip N. 75° W. The country along the proper
place for the continuation of the quartz, and all the adjacent towns, have
been carefully explored in search of further exposures; but, like the other
range, this seems to come to an abrupt termination, and the proper
explanation of its behavior remains to be satisfactorily set forth. It
may be stated, however, that two parallel ranges of similar quartz occur
in Royalston, Mass., the northern about two miles south of a Baptist
church, and the southern close by the village of Pine Dale. One of
them comes within the limits of our general map, where it is designated.
It is twenty-one miles from the last exposure in Temple, and the direc-
tion is S. 62° W., almost in the proper place for the extension of the
Hooksett range. Both older and newer formations intervene, and I am
disposed to think the Royalston ranges belong to another fold, and con-
sequently a parallel line of exposure,

A few words about the relations of these ranges to each other. At
their beginning in Hooksett they are four and one tenth miles apart.
They gradually diverge till we reach the breaks in New Boston and
Amherst, where they are seven and a half miles apart, directly op-
posite each other, the extreme ends being eight and two tenths miles
distant. The next appearances in Lyndeborough and Wilton are four
and three tenths miles apart, and their south-western termini in Temple
and Mason are seven and two tenths miles apart. At Royalston the
exposures are four and a half miles distant from each other. Before

544 STRATIGRAPHICAL GEOLOGY.

drawing conclusions from these facts, it will be well to describe a few
carefully measured sections from one to the other range in Goffstown,
New Boston, Wilton, etc.

Sections across the Quart::; Ranges. In Fig. 87 is a somewhat gener-
alized section from the Oil Mill station in Weare to the locality on the
west line of Manchester, This does not run square across the strike.
The quartz dips 70° N. 25° W., and is followed by a nondescript siliceous
gneiss with the same position. Between here and Goffstown the ledges
are mostly concealed by alluvium. From the study of the rocks not far
away it is believed the first rock next the quartz is a gneiss, breaking
naturally into long angular pieces. Next is a large amount of fine-
grained granite or granitic gneiss, dipping perhaps 65° N. 40° W., as at
J. Butterfield's, on the south side of the river. This band passes up
the west flank of the Uncanoonucs. There is then a gneiss extending
to the east part of West Goffstown village. Next is a broad band of
coarse mica schist, cropping out along the road for a mile and a half,
nearly to the centre village. This is the range occupying the space
between the two Uncanoonucs, farther south. Gneiss succeeds, a nar-
row band occurring where the road bends to the north-east to enter the
village. This is followed by narrower belts of mica schist and gneiss
before reaching a broader mica schist strip at the west end of Goffstown
centre. It is mostly mica schist, with a north-west dip for a mile's
width. The rock is somewhat ferruginous and coarsely grained. There
is a coarse granite at E. Sargent's, which may be followed a mile north-
easterly on the road to the north-east corner of the town. Beyond the
first mile of this north-east road the ledges are concealed by drift. East of
Sargent's, on the Manchester road, is a few rods width of mica schist,
but the rock is mostly coarse granite to a bend in the road east of E.
Whitney's. The same may be seen on the southern slope of the hill
towards the river. This is succeeded by a half a mile width of granite,
in texture like that quarried in Hooksett. This is somewhat coarser
than the Concord variety, but otherwise closely resembling it. Near L.
Hunkins's or W. Wortley's gneiss is found, which continues to the east
line of the town. A portion of it, by E. Morrill's, is usually white and
siliceous. About a quarter of a mile's width adjacent to the quartz,
mostly within the limits of Manchester, is composed of a coarse mica

Fl ^te XXII,

n/^4fL A K E G^N E I S S. ^^ UjlcanooiUK- Alis. ^

yM^MjMwMmm^mwmy^^^^^^ ^^

(i/iiih

F/G.S8. From New Boston to Bedford over Uncanoonuc Mrs.

%.^

^ A<» "5? L A K E J^ 0* G N E I

>S irf o- A* r-T-n 'TT—r-, —

<3 ^^ ^r£'.co£ner«r>^'''^"t. ^ r

'3 ^"

/i'

L<Va K E j? ^* G M E I S S . V? ^

FiG.Sd, From New Boston to the South Part of Bedford.

-'-^^

.y,^" Lake Gneiss.

F/6. 90. South Lyndeborough roMiLFo/to. Fig.^2. Amoskeag Village to S.E. corner

OF Manchester.

Fig. si. Section from Temple to Brookline.

^ 0 *

& it

i'G n/e I s s . ^"'

^y'-S <f MicaSchisx. i»^ »;i«

- -^ '^,^0 0 0

.^'

FiG.d3. Section IN Derry and Salem. Fig.S4-. Section through New Ipswich

SCALC, HORI^OrVTALLY, 2% MILCS TO AA/ /fVCH ; V £ KTI C A LLY , SOOO rECT TO Arv //\/CH.

'^

GEOLOGY 07 THE MERRIMACK DISTRICT. 545

schist, with a granite to correspond to it in texture. The dip of all these
rocks in this section is north-westerly. The western part of the quartz
seems to be somewhat calcareous. If the soil were cleared away, beds of
limestone might be found.

On the south side of the river through Goffstown, on a line parallel
to the section about a mile distant, the correspondence is not perfect.
West of Goffstown the conditions do not allow comparison. To the
east we find close to the village a large mass of granite that has not
been observed in the mica schist across the river. Opposite the centre
village the band of gneiss is much broader. The granite on the south
side is less abundant, and disappears altogether before coming to the
south part of the town. The white gneiss of E. Merrill's is repeated at
C. and D. Wyman's. The place of the quartz near J. Black's is under-
neath the sand. There is an interesting assemblage of igneous boulders
by a watering-trough at the second fork in the roads east of the Centre
station. It is a sienitic conglomerate, mostly of mica schist fragments,
suffering much from weathering, which I have nowhere found in situ.
The pieces may be four and five inches long, consisting of gneiss, gran-
ite, mica schist, and quartzite. A careful search of the adjacent region
disclosed very large blocks of it at the bottom of the sand hills towards
the river, smaller pieces at E. Moore's, in Bedford, about three miles
south from the stream, and none on the north side. Our conclusion is,
that the ledge from which they were derived exists underneath the
meadow of the Piscataquog river, not far from the station and village.
On the road between the quartz at M. W. Woodbury's, at the Dunbar-
ton and Goffstown line, and the Merrimack, all the ledges are inverted,
as both ranges dip north-west.

Fig. ?>d> shows the order and position of the rocks on a sectional line,
cutting both quartz bands, through the Uncanoonucs. It is assumed
that the quartz has the same position here as the strata on both sides,
namely, a dip to the north-west. Near the eleventh mile-post from Man-
chester, where the section crosses the Piscataquog river in New Boston,
gneiss with coarse granite veins dips 60° north of west. Granite is seen
at the west base of the Uncanoonucs, just by the west line of Goffstown.
Gneiss succeeds, dipping N. W., and is supposed to constitute the bulk of
the first of the twin mountains. Mica schist occupies the space between,
VOL. II. 69

546 STRATIGRAPHICAL GEOLOGY.

reaching to the summit of the east and highest Uncanoonuc. There is
a large granite vein here also. At the east base of the mountain, back
of J. Person's, is gneiss, which may connect with that in the edge of
Goffstown Centre, upon Fig. 87. Mica schist next occupies the field
nearly to E. Dana's, save a narrow band of gneiss at G. Robertson's.
Gneiss occupies the rest of the way. The granite and schistose bands
found near the east band of quartz on Fig. ^ty, if present, are concealed,
as well as the quartz itself, beneath the drift. All the dips on this sec-
tion are also to the north-west.

Fig. 89 illustrates the positions on the next line, perhaps the most
carefully explored of any, from P. Dodge's in New Boston to the north-
east corner of Amherst. The quartz dips 80° N. 80° W. Close to it is
a hornblende rock, almost a trap or sienite. Between W. Whittemore's
and N. Hall's, beds of mica schist with coarse granites occur. At New
Boston village are interstratified gneisses with twisted seams of coarse
mica schist. To the south-east thick drift deposits conceal the rocks,
supposed to be essentially gneiss, as far as A. Leach's, where it contains
ferruginous fragments, and is very much twisted, dipping in a general
north-west direction. By J. Fairfield's the gneiss dips 85° N. 60° W.
At the north base of Joe English hill the gneiss is much like the Concord
granite. The mass of the mountain is composed of similar material,
dipping 65° N. 80° W. This is a little south of the section. At S. Moor's
are other ledges, and at the school-house by a saw-mill, the gneiss carries
coarse granite veins dipping 15° N. 25° W. Following up the stream a
short distance, away from the regular road, are similar rocks tending to
dip in the opposite direction. Near here is the proper commencement of
a range of mica schist, that running between the Uncanoonucs, dipping
60° N. 50° W. Numerous granite veins or beds occur with them. On
top of the hill, near the west line of Bedford, these schists dip 75° N. 35°
W. They also crop out east of W. A. Hobart's, and along the east road
in the north-west part of Bedford, as far as W. D. and J. F. McPherson's.
Almost at the south line of Bedford, next Amherst, gneiss dips N. 40° W.
Next we find ourselves at the limestone quarry and quartz in the north-
east part of Amherst, with the dips of 80° N. 50° W. A short distance
northerly, in Bedford, there is a northerly-dipping gneiss.

Fig. 90 illustrates the rocks from South Lyndeborough to the west

GEOLOGY OF THE MERRIMACK DISTRICT. 54/

pirt of Milford, through East Wilton. The quartz dips 78° S. 40° E.,
just beyond a railroad cut through a hard sienitic rock. In the south
edge of the village, following the carriage road instead of the railroad, the
next interesting rock is a granite like the Concord in general appearance,
but full of small, distinct crystals of feldspar. This being of peculiar
aspect is easily recognizable, and will be mentioned as occurring at the
west end of the next section. The sienite rock at the railroad cut also
reminds us of the related rock near Dodge's, at the west end of Fig. 89.
The gneiss adjoining this porphyritic granite dips 85° N, 80° W. Drift
conceals the ledges for more than a mile. Ferruginous mica schist,
dipping 70° N. 25° W., crops out shortly after crossing the stream, in the
north part of Wilton. At the next crossing of Stony brook the mica
schists dip 40°-45° N. 40° W., and are inclined at a smaller angle beyond.
Half a mile farther they dip 30° in the same direction, with coarse granite
beds. Near a cabinet shop the dip is 65°, Just in the edge of East Wilton
is a coarse granite. At the village is mica schist. At the tannery, in the
east part of the village, are veins of coarse granite, with a small dip.
The dip is 75° N. 75° W. near the new factories, in the west edge of
Milford, before crossing the river. The rock next the quartz on the hill
in Milford, already alluded to as dipping 75° N. 70° W., is hardly a gneiss.
The greater part of this section has been occupied by a low-dipping,
coarsely-grained mica schist, the equivalent of those in Figs. 87, 88.

Fig. 91 illustrates the rocks between Temple and the east line of Wil-
ton. The sienitic rock of Figs. 89 and 90 is wanting next the quartz.
The gneiss west of the quartz is of the angular-breaking kind, dipping 70°
N. 80° W. Between the quartz locality and a north-east road from Tem-
ple, the gneiss contains much feldspar, and dips 65° N. 70° W. It is ob-
vious that the quartz must correspond with these dips just recorded of
the gneiss upon both sides of it, its own inclination not readily showing
itself. The porphyritic granite seen in Lyndeborough is much thicker in
Temple, making its appearance next on the south-east road from the village.
Next is granitic gneiss, followed by ferruginous mica schist, half a mile
distant from the hotel, dipping 85° N. 50° W. on the average. The roads
are now inconveniently located for our purpose, and the next ledge seen
is at West Wilton, two miles distant from the last ledge, but as it courses
with the strike it cannot be far distant from its place on the section. There

548 STRATIGRAPHICAL GEOLOGY.

is a mixture of coarse mica schists and fine-grained granitic beds dipping
about 65° N. W. Half way to Wilton the mica schist dips 30° N. 25° W. ;
also at Wilton, No ledges appear for a mile and a quarter on the section
line, when we find a spotted granite by H, F. Frye's, on the north-west
slope of a high hill. There is gneiss higher up, and at intervals to B.
Gray's, On the hill west of Gray's the rock is micaceous and gneissic,
dipping 80° N, 70° W., and that is also the position of the quartz. This is
about two miles from the south-east end of Fig, 90, There is a great
width of gneiss here at Gray's, though its place seems to be taken by
mica schist on Fig, 90, The gneisses, porphyritic granite, and mica
schists observe the same order as on Fig. 91, in proceeding from Temple
towards Greenville. There is a possibility that the rocks of New Ips-
wich and Greenville are older than those carrying the quartz, and hence
cut it off by rising to the surface. We have taken other observations
respecting the rocks between Figs. Sy to 91, which will be presented
later. The mica schists of these sections are supposed to belong to
the Rockingham series.

Coiichtsions. These are not altogether satisfactory, i. We think the
quartz bands are stratified, and connect in a synclinal manner with each
other, though inverted. Fig. ^% shows repetitions of a basin character, but
not in a decisive manner. The comparative recency of the mica schist is
apparent. It lies like a blanket upon the older gneiss. All the sections
can be explained in the same way, especially Fig, 90, where the quartzes
dip towards each other, 2, The southern segment of the Hooksett range
has a decided tendency to dip south-east., as shown through Lyndebor-
ough. The Manchester range invariably dips north-westerly. This fact
seems to confirm the theory of a synclinal connection between these
bands. 3, It would seem as if there had been a great fault in the strata
between Amherst and New Boston, so as to explain the absence of the
bands over so great a distance, 4, South of the break the bands are
much nearer each other than to the north ; yet the synclinal structure is
seen clearest where the compressions were most powerful, granting that
lateral force was the cause of the break and of the crowding together.
5, The Greenfield spur of porphyritic gneiss is parallel with the quartz
band, and extends exactly the same distance to the north-east, while
beyond there is an expanse of the Lake gneiss directly opposite the

GEOLOGY OF THE MERRIMACK DISTRICT. 549

break in the quartz. 6. The mica schist seems to have been deposited
after the first period of elevation affecting the Lake gneiss. Hence the
mountains of it in the Pack Monadnock and Lyndeborough ranges may
not have exerted a marked influence in producing the break. It could
easily conceal quartz bands by covering them up. 7. An anticlinal ridge
composed of quartz would withstand denudation much longer than the
enclosing rock alone. Hence certain comparatively isolated ridges of
this quartz may represent the tops of underlying formations. Such are
the supposed continuation of these quartz bands in Strafford, Wakefield,
Effingham, far beyond the limits of the Merrimack district. 8. Quartz
bands similar to these occur in the Montalban and Bethlehem gneiss ;
also in the Lisbon, Merrimack, and Rockingham groups. They occur on
both sides of the central ridge of the state, usually much more isolated
than the cases recently considered. Care must be exercised not to con-
found together these bands that were deposited in different ages. 9. The
occurrence of fragments of quartz in the drift throughout the state
furnishes admirable illustrations of the dispersion of boulders by the ice.
Many localities have been discovered through their instrumentality, and
we have evidence to suggest the existence of these ledges in localities
now obscured by surface accumulations.

Additional Fads. There remain to be stated a few further facts and
observations respecting the gneisses between and to the north of these
quartz ranges. In Hooksett, three types of rock approach one another,
and I do not feel satisfied that their respective limits have been properly
assigned. The distinctions were not drawn till after the comjoletion of
field work, and therefore perplexing questions arise respecting the proper
hmits of each. The ferruginous and Rockingham schists contain large
granite beds, which often closely resemble the Concord granite. When
the adjacent schists are intermediate in texture between the Rockingham
and Montalban, it becomes difficult to decide with which formation a
particular granite should be placed. There is also a close resemblance
between the Concord granite and some of the Lake gneisses, as, for
instance, those of Salem. The radical distinctions between all these
groups are well founded, and if opportunity were afforded for further
examination of their distribution, I do not doubt that entire satisfaction
respecting their territorial limits would be attained. As it is, I will draw

550 STRATIGRAPHICAL GEOLOGY.

the lines as well as possible, and beg the indulgence of future observers
should any of the boundaries prove to have been incorrectly delineated.

Subject to these modifications, therefore, I shall include the Allenstown
quartz with the Lake gneiss, and draw the northern boundary of the forma-
tion a little beyond what the mineral character of the rock would seem
to warrant, including quite a large portion of Allenstown. This will bring
the well-known Hooksett granite into the Lake series, as well as that of
Manchester. Either one of these deposits might be said to be a Mont-
alban synclinal outlier, resting upon the Lake gneiss, should the imme-
diately associated layers make such reference desirable. I have not
separated the granites of the Lake series from the gneisses on the map,
as is the case with the Montalban. Near the east corner of Hooksett,
upon Gate's hill, is a hard, jointed, granitic gneiss, just beyond the quartz.
Two lines of travel cross the country farther west in Hooksett, between
the two quartz beds, nearly at right angles, and may be taken on either
side of the Merrimack river. Starting with Campbell's hill, we find the
quartz dipping north-west, and then the rocks are concealed by allu-
vium for more than a mile. Next follow nearly two miles' width of the
granite that is so extensively quarried on the hills east of the railroad.
The sheets of granite on the hill dip from forty to fifty degrees north-west.
The strata are more nearly vertical half a mile north, with large veins of
very coarse granite. On both sides of the Pinnacle quartz range are hard
granite layers. In the river below the railroad bridge the rock is dis-
tinctly gneiss. The dips are north-westerly. On the west side of the
river, in Hooksett, all the strata .dip in the same general direction. A
coarsely crystallized rock crops out by W. Taggart's. The road nearest the
west part of Manchester and Goffstown runs over granite similar to that
quarried, save a patch of mica schist, at the south corner and on the very
west, line dipping io° N. W. Adjacent to Bow line the soil is entirely
ferruginous, and the rocks very much so. The granite is quarried some-
what in the bend of the Merrimack river in the south part of Hooksett.

New Boston is mostly underlaid by the Lake gneiss. The most
characteristic lines of outcrop have been discribed in Figs. 88 and 89.
Gneiss is the prevailing rock on the high land parallel with the Piscata-
quog river on the north side. It occurs near the village, two or three
miles south, by B. Hopkins's and a saw-mill. The layers resemble

GEOLOGY OF THE MERRIMACK DISTRICT. 55 I

mica schist at the looking-glass factory a mile south of the village.
Between Joe English hill and the south town line gneiss abounds and
is well defined. Its southern limit towards Roby hill is near the
south line, and near Joe English pond on the south-east. Between
the pond and hill the rock is not so clearly defined. At the base
of the hill are possible strata dipping only 30° N. W., containing
segregated veins. The south side of Joe English hill is a precipice.
Gneiss occurs by J. Cochran's, about three miles south-west from New
Boston village ; about Colby's pond, in the south-west corner of the town ;
and about the mills, in a small hamlet adjacent to the east. Nearly oppo-
site North Lyndeborough post-office, by I. Gage's, is the most western ex-
posure of the gneiss in this town. The north-west part of Mont Vernon is
made up of the same rock. By E. A. Green's the gneiss dips 30° S. 70° W.
The same rock appears at W. Odall's. The south end of Piscataquog
mountain, in Lyndeborough, has not been examined. On the west side of
Badger pond the rock is like the Concord granite, and is used extensively
in the neighborhood for underpinning. The dips about Lyndeborough
centre are high to the north-west. It has a similar character two miles
to the south-west, near S. Cummings's. A hard granitic gneiss occupies
the country in the valley of Stony brook for about two miles west of
South Lyndeborough. The range runs through the north-west part of
Wilton to Temple. The dip in Wilton is north-west. The New I^DSwich
rocks present difficulties just like those at Hooksett. It is very likely that
this Temple range crosses Barrett mountain near the state line, and also
follows the boundary to the east, so as to connect directly with the
Manchester range, and perhaps cause the mica schist deposit to termi-
nate near the village of New Ipswich. Our observations are so scanty
that it cannot be affirmed that the schists do not converge somewhat at
the village, and then extend into Massachusetts. The particular charac-
ter of the rocks and positions through Greenville and New Ipswich may
be best learned by referring to the description of Section I. In the south-
west part of the town I have collected gneiss by W. Young's, dipping
irregularly S. 60° W. On reaching the ridge of the hill a mile farther
north-east, the dip is much the same, greatly crumpled. Near J. Nut-
ting's, on the east side of the ridge, the dip is N. 35° E. There seems to
be an anticlinal in this rock on the ridge. At the chair shop the schists

552 STRATIGRAPHICAL GEOLOGY.

have become ferruginous. The next ledge seen near the state Hne is
near W. Frissell's, in the south-east corner of this town, seeming to dip
only 5° N. E. This may be a part of the more eastern range.

The strip of gneiss on the east side of the mica schist is very narrow in
Bedford, but widens out in Amherst. On the map it seems to make one con-
nected mass with the more eastern range, but the presence of the quartz
furnishes us with a fixed stratigraphical boundary. There is little to note
of this rock before coming to Amherst, save where it is crossed by the
section in Fig. 89. The gneiss in the north part of the town dips north-
west. There is a good exposure by S. Austin's, near the Mont Vernon
line, and at J. Mark's, close by Williams pond, dipping 50° N. W. About
a mile north of Amherst village is a new quarry of granite, or of granitic
gneiss, which clearly belongs to the Lake series. The direct road from
the village to Mont Vernon is mostly over a plain, and drift, after begin-
ning to climb the hill. At W. Richardson's, a little way into Mont Ver-
non, the gneiss is well-defined, and dips N. 25° W. To the south, in
Amherst, at W. Pratt's, the same rock dips 20° N, W. At L. Elliott's is
a limited outlier of coarse mica schist standing vertical, with the strike
N. 75° W. This strike also shows itself at T. Patch's, about a mile west
of the village. The north part of Milford is supposed to be occupied with
the granite that is quarried so extensively farther south. At the south-
east corner of Lyndeborough this gneiss appears, and it is near the east
line of the mica schist group. Figs. 90 and 91 show the occurrence of
this rock in the east part of Wilton. Similar ledges of gneiss occur in
the south-east part of Wilton, and the north-east part of Mason as far as
the quartz extends. There is a granite at Elliott's mill in Mason, which
is the last of the rocks to be described in connection with the quartz.
The gneisses and granites farther west properly belong to the next range.

A review of all the positions of the gneiss noted between the mica
schist and the Manchester range of quartz shows a uniform pitch towards
the north-west, varying to north. The last may possibly belong to the
next range, which had been crowded — at Amherst village — to the south-
east, and passes nearly due west, directly to join the north end of the
western quartz band. More light is required for the satisfactory un-
derstanding of the break in the quartz. Perhaps the difficulty may
be removed by disregarding the quartz outcrop near Amherst village

GEOLOGY OF THE MERRIMACK DISTRICT. 553^

and thus making the range touch the south-east corner of Mont Ver-
non.

The Dcerfield and Mason Range. We are introduced next to a ma-
terial somewhat different from the ordinary gneiss of the Lake series. It
is thoroughly and coarsely crystalline, being generally much more sac-
charoidal in appearance than even the typical varieties about Winnipi-
seogee, and not so fine. It is more like the Laurentian gneiss of typical
localities than anything else in the state, except a range of similar type
passing through Berlin. In some early publications I have spoken of
this formation as the Manchester or Berlin gneiss. Were it not for mul-
tiplying distinctions it might be well to separate this from the other
ranges ; but it approaches the Lake gneiss more nearly than anything
else, and therefore may be classed with it. Supposing it to underlie the
series associated with the quartzes, it would be repeated in the Weare
and Dunbarton range on their north-west side. The latter are very
crystalline in their aspect, though readily referred to the Lake series.

Another peculiarity of the Manchester range consists in its ready pas-
sage into granite, together with a disposition to a minute twisting of the
strata. The readiest method of understanding this peculiarity is to
imagine a thorough squeezing of the rock from both sides, and then a
melting of the curled layers sufficiently to cause many of them to disap-
pear by conversion into genuine granite. Much of this rock would
pass for a true granite, full of miscellaneous patches of twisted strata of
mica schist. There are also bands of a coarsely crystalline mica schist
connected with this gneiss, which are of the same age, and not to be con-
founded with the later formation so extensively developed in Rockingham
county.

This range extends farther east than Deerfield, but our descriptions
must commence with the line separating the Merrimack and Coast dis-
tricts, which is the height of land between the hydrographic basins of the
Merrimack and the Lamprey and Exeter rivers on the east. On reference
to the map it will appear that Deerfield is mostly excluded from the Mer-
rimack district ; Candia is divided transversely into equal parts ; Chester
is mostly east of it, and Derry is situated upon both sides of the line.

The following represents the rocks on a line from Campbell's hill, in
Hooksett, to the Candia ridge. Campbell's hill is of quartz. Half a mile
VOL. II. 70

554 STRATIGRAPHICAL GEOLOGY.

south are imperfect gneisses with interbedded granites, dipping 30° north-
westerly. Near the quartz a more careful measurement indicated a dip
of 50° N. 30° W. Traces of similar rocks are to be found all the way to
Sawyer's pond, the materials being very crystalline close to the water.
At M, Collins's, east of the pond, the layers are micaceous, dipping 50°
N. 30° W, Not a great distance beyond are layers of granite, entirely
devoid of any marks of stratification, arranged between seams of mica
schist. Wherever the schists are bent, the granite layer is also curved in
conformity with them. These granite beds are from one to six inches
thick. With them are occasional bunches of crystalline feldspar, eighteen
inches thick. Rude crystals of quartz occur in some of the feldspar
bunches. Before reaching the old Rowe's station on the C. & P. Railroad,
a ledge of granite appears. This is the height of land, and, consequently,
the eastern boundary of our district.

Near the south line of Hooksett, next to Manchester, feldspathic schists,
with narrow granite seams, dip N. 30° to 50° W. Similar rocks occur
occasionally all over the north part of Manchester. At the Trotting
Park is a ledge of similar character, planed down thoroughly by ice. A
little south of the Reform School is a field of granite which has been quar-
ried. This points to the similar material on the west side of the Amos-
keag bridge. Opposite to it, near the river, are ledges of micaceous gneiss.

There is a great amount of glacial drift in Manchester, serving to con-
ceal ledges, yet many exposures of rock may be seen. There is an inter-
esting bunch of granite less than a mile north-east from the Amoskeag
reservoir, quarried by the Amoskeag Company and by Bodwell. One
would judge from the appearances that this granite occupied an elliptic
space in the midst of coarse mica schists. It might be said to be a
gigantic egg-shaped concretion, containing the good materials segregated
from the surrounding uncouth rock. Such an impression is not gained
for the first time from the inspection of these quarries. I have thought
of the same illustration at Fitzwilliam and Concord. Early in the work-
ing of the Bodwell quarry I noticed that a species of cap rock extended
over the granite. This required to be blasted away before good stone was
found. But the presence of a cap rock was not universal. On the south-
east side of the Amoskeag quarry coarse mica schist dips 75° N. 20° W.,
and also more north-westerly. The granite runs against the edges of the

GEOLOGY OF THE MERRIMACK DISTRICT. 555

schists at the south end of the quarry, and the two rocks adhere together,
though not firmly. In Bodwell's opening there is a plain line of separa-
tion between the two, almost a fault. The granite is apt to be of inferior
quality when it approaches the walls. The material is related to the Con-
cord, but it is coarser and breaks more readily into angular pieces. It lies
in sheets, dipping io° N. W., while the rock on the east side (Bodwell's)
stands vertically, with the strike N. 60° E. On the north sides are very
large veins of coarse and graphic granites, standing like chimneys. There
are splitting planes in the granite, parallel to the walls. The action of the
glacial force in breaking the rock on top of the ground is well shown in
these quarries.

The mammoth road passes near these quarries, behind them, and the
rock there is the schistose variety. Farther south, on Hanover street
crossing, the gneiss runs N. 50° E., the strata vertical. There are several
small anticlinal folds, a yard wide, seen here. A few streets to the west,
on the crest of the hill, are irregular and coarse granite veins. Many
veins in Manchester consist of nearly pure feldspar. I have occasionally
seen limestone seams two inches wide in the gneiss. The twisted rocks
east of Sawyer's pond, Hooksett, and Candia lie to the east of the schis-
tose ledges holding the granite nodules. They commence at about the
crossing of the mammoth road and Hanover street. Ledges occur occa-
sionally between the ridge east of the city proper and Massabesic lake
composed of this rock. By the Methodist church south of Hallville, this
gneiss dips 85° S, 30° E. Half a mile west of the extreme south end of
Massabesic lake is a quarry in this rock, the blocks extracted from which
have been largely used in the buildings of the city. The foundation stones
and steps of the city hall are of this character. Between the pumping
works and Massabesic lake the gneiss dips 80° S. 60° E. The most south-
east ledges of this rock observed are about a mile south of the lake, in the
south-east part of the town, dipping 65° S. 50° E, The very corner, for
half a mile, is occupied by a coarse mica schist. The change is first
indicated, in proceeding south-east, by the enormous blocks of the schist
by A. D. Coming's. Gneiss dipping north-east occurs on the promontory
at the north-west end of Massabesic lake, a short distance within the town
of Auburn. The north end of the lake is sandy and swampy, but a large
promontory west of the village is composed of gneiss dipping N. 70° E.

556 STRATIGRAPHICAL GEOLOGY.

The rocks on the south-east side of the lake are of the mica schist divi-
sion. The whole of Candia is occupied by this twisted gneiss, and most
of our observations relate to the ledges on the eastern slope. The dips
south of the railroad are generally to the south-east. To the south of
Manchester we find a large number of white ledges of this rock below
Bakersville, and on the south-west side of Cohass meadows, on the road
to Londonderry. Another ledge appears at the fourth mile-post on the
same road. It extends into Londonderry as far as R. White's and E.
Young's, with the dip south-east. These observations evidence the exist-
ence of a main anticlinal axis in this range, and are embodied in Fig. 92.
Passing to the west side of the Merrimack the rocks are found to cor-
respond with those already noticed. The twisted varieties are all on the
south-east half of the range. At Amoskeag falls one can examine a large
variety of ledges. The basis is a coarse mica schist, dipping north-west,
varying to N. 10° W. This contains four or five thick masses of very
coarse granite. The very conspicuous bosses of rock seen in the falls
consist of this latter variety. Smaller inconsequential veins may cut the
strata, like two of somewhat similar character near the west end of the
bridge. Some of the schists contain large egg-shaped nodules of a
quartzose character. The granite is often graphic, and contains tourma-
lines. The schistose rocks may also be well seen upon the island, a
quarter of a mile to the south. In Amoskeag are extensive ledges of
granite similar to that quarried to the north-east of the reservoir. There
is mica schist on the north side of Black brook. Near Rock Rimmon is
a ledge of coarse granite similar to that in the falls, and with it consider-
able of the finer grained material, which has been quarried. It is some-
what ferruginous. The dip is northerly and N. 20°-30° E. On climbing
the rock itself the material is seen to be distinctly gneissic, some layers
being very coarsely crystalline. On the south-east side the dip is S. 85°
E. ; on the south-west side the dip is N. 85° W, ; at the north end ^y" N.
The strata are often curved along the strike. None of the dips are the
prevailing ones, and the peak looks as if it had been subjected to rough
pressure. It is isolated by its situation in a sandy plain, — being the rock
seen so conspicuously to the west from the streets of the city opposite.
South of the Piscataquog river, in the village of the same name, we
observe first several ledges of the mica schist variety, dipping 65° north-

GEOLOGY OF THE MERRIMACK DISTRICT. 55/

west. The band shows a width of certainly seventy-five feet. Gneiss
appears at the road fork nearly half a mile to the west, and also near the
town line on the Bedford road. On the most northern line of roads
through Bedford the rock is gneiss as far as J. Witherspoon's, save a
single ledge of mica schist at Mrs. Mullett's,

Taking the direct road to Amherst from Piscataquog, all the ledges
seen through Bedford are gneiss. It crops out prominently at Bedford
village, and a little beyond. Near McQuade's brook, east of G. Fletcher's,
is a mass of granite related to that in Manchester. There is more of it
half a mile to the north-east. It is probably another ovoid mass at about
the same stratigraphical horizon, as well as that in the quarry near Am-
herst village. At S. P. Campbell's, gneiss dips northerly. On the north
and south road, near the north-east corner of Amherst, are ledges ap-
proaching mica schist in character, and containing very much coarse
granite. South from J. P. Conner's the gneiss dips 85° N, 40° W. Other
ledges of this rock occur farther along, — notably, west of W. E. Brown's,
in Amherst ; west of Williams pond, dipping 50° N. W. ; a mile north of
the village, vertical, with strike N. 20° E., and elsewhere. South of Wil-
liams pond, the country is mostly covered by drift as far as the village.
The hill south of the court-house is clearly occupied by this ancient
gneiss, as it is also farther west. On the road to Milford, near the height
of land, west of A. Hartwell's, it dips 85° N. 30° W. In Milford is a large
mass of granite, occurring very nearly on the line of the Manchester
quarries. It is extensively quarried about three miles north-west of the
village. I noted the two usual sets of joints in this rock at one of the
quarries, about 10" W. and 80° E. The gneiss is quite well developed
along the banks of the Souhegan, at Milford village.

South from Piscataquog village, along the river road, are ledges of
various sorts. At the village is the coarse mica schist previously men-
tioned. Near the south town line is a red crystalline gneiss, dipping N.
20° W. This belongs to the twisted crystalline variety. Bowman's
brook obscures the ledges for the next two or three miles, and we observe
the return of the ancient gneiss at the easterly turn of the road near J.
Walker's, Bedford. The ledges approach the river here, at the expense
of the modified drift. They are also numerous near Goff's falls. Farther
south, by C. K. Ball's, this twisted gneiss dips 88° N. 40° W. Layers of

558 STRATIGRAPHICAL GEOLOGY.

dark micaceous gneiss are interstratified here with the common variety.
The next ledge seen is at Reed's ferry, in Merrimack ; then at the cross-
ing of McOuade's brook, near its mouth, with south-east dip. At the
crossing of the Souhegan river, in the village, the coarse mica schists dip
70° S. 40° E. No related rocks appear farther south. It would appear
from this line of outcrops that the twisted gneisses possess an anticlinal
structure, and are flanked on both sides by a coarsely crystalline mica
schist, evidently belonging to the same general series, and not to be con-
founded with the Rockingham group. It is the same with that at Amos-
keag falls.

The next route traversed was from Thornton's ferry, across Merrimack
and the south part of Amherst, to Milford. Perhaps a mile and a half
back from the ferry is a small ledge of the coarse mica schist with granite,
beyond R. H. Pratt & Co.'s, dipping 80° S. 25° E. A coarse granite
occurs next, west of the school-house, midway across the township. Just
in the edge of Amherst is a coarse granitic gneiss, dipping 50° S. 55° E.
This region is covered by wide-spead alluvial deposits, which greatly
obscure the ledges. At Danforth's Corner, or South Amherst station,
the very twisted gneisses appear in their characteristic development. At
the west town line a fine-grained granite, like the Concord, succeeds.
It may be seen from the road, also, about a mile and a half south of Mil-
ford, by means of the openings that have been made for quarrying.
There may be an anticlinal on this route.

South-west from Milford there may be a similar granite as far as
Osgood's pond. The gneiss dips north-west by E. B. Tuck's and A.
Gutterson's. Taking the south row of towns next, we find the eastern
border of the gneiss near the town lines of Brookline and Hollis,
a mile north of Massachusetts, and part of this route agrees with that of
a section from Temple to Brookline, Fig. 91. West of F. Smith's the
gneiss dips south-east. By L. Sawtell's there is a coarse indigenous
granite, with the same position. Several varieties of gneissic rocks are
found near N. Farrar's, a mile west of the town line, dipping 60° S. E.
Next, there is a plain for a mile and a half to Brookline village, where
the gneiss contains distinct crystals of feldspar approaching the por-
phyritic variety, with the same dip as before ; here it is 65° S. 70°
E. A little west of the village is some mica schist and granite, dip-

GEOLOGY OF THE MERRIMACK DISTRICT. 559

ping 50° S. 55° E. South and west of Potanopa pond is a fine-
grained granite that has been quarried somewhat. It has a rusty color,
so far as seen. At the very west end of the pond, by E. Wheeler's,
the granitic gneiss dips 50° S. 35° E. In the east part of Mason, or
about the town line, there is an anticlinal. At W. Scripture's, coarse
and fine granitic gneisses intermingled, dip 50° N. 70° W., — the dip being
about north-west half a mile to the east. A mile west of Scripture's, the
gneiss is coarser, dipping 40° westerly. There is a dark micaceous
variety between the Peterborough & Shirley Railroad and Mason centre.
The dip is 15° W. at Mason. On the summit of the ridge west, midway
between the post-office and the west line of the town, the granitic gneiss
dips 20° N. 85° W. Essentially the same dip occurs on all this high
land, certainly for two miles to the north. On a parallel line two miles
to the south, we find the rocks much like what has been described.
Gneiss at R. L. Cumnock's and at C. Blood's, near the railroad, dip 50°
N. 30° W. The ledges all over Mason resemble that of Lake Winnipi-
seogee, both in its granitic aspect, and the presence of segregated veins.
Between Mason and Greenville the ledges are abundant upon the high
land, dipping at a small angle to the north-west, near the first named
village. The dip is north between A. Elliott's and the railroad crossing,
and the mica predominates. By Pratt's pond and the edge of Wilton are
extensive granite quarries. The texture is fine, somewhat like the Man-
chester variety. A similar material is abundant by Elliott's mills, and
still farther north-east. Mica schists at Pratt's pond dip north-west. On
the hill west, small eruptive outbursts of the Manchester granite occur
frequently. In one place there is a ledge of porphyritic gneiss. Granite
is quarried between L. Joslin's and A. Elliott's, a mile south-east from
Greenville village. At the cemetery south of the village, the granitic
gneiss dips 25° S. 70° W. In the edge of the village there is another
ledge similarly situated. Our observations are meagre for the south-
east part of New Ipswich and the south-west of Mason, where this Lake
gneiss is supposed to extend. We find in Ashby similar rocks, and in
the west part of Townsend a fine-grained granite.

Conclusio7is. I. The rocks of this Mason and Manchester gneiss area
are arrayed in parallel bands, according to their character. The north-
west part consists of micaceous gneisses and schists, holding layers of

560 STRATIGRAPHICAL GEOLOGY.

indigenous coarse granites. The south-east part is made up of the crys-
talHne twisted variety of gneiss. 2. There is a row of ovoid masses of a
fine-grained granite from Manchester to Mason, all having a similar char-
acter, and contained within the micaceous part of the formation. They are
the Amoskeag and Bodwell quarries to the north-east, that near Fletcher's
in the west part of Bedford, and those near the villages of Amherst, Mil-
ford, and Mason. This line is one along which those needing this material
may search for new localities. 3. There is a well marked anticlinal in
the south-eastern part of this range, confined to the twisted gneiss. It
would seem to commence near the west part of Candia, pass near the
north end of Massabesic lake, north of the city reservoir, Manchester, the
south-east corner of Bedford, Danforth's corner in Amherst, and the
south-east corner of Mason. 4. On both sides of this anticlinal is a very
coarse mica schist, different from the Rockingham group. It has not
been traced throughout the range, because attention was not directed to it
sufficiently early in our explorations. It is not distinguished on the map.

Hampstead and Pelham Range. The east boundary of the Mer-
rimack district being rather indefinite in the south part of the state,
I will regard, for convenience, this gneissic area as its south-eastern
limit, and not describe the gneiss beyond Hampstead, so as not to
encroach upon the maritime district. This is an independent range.
In its character it is losing the peculiar features of the Lake gneiss, being
intermediate between that and the Concord granite. The range may
commence in Epping and terminate in Massachusetts, only a short
distance beyond the limits of our map. It terminates because covered or
surrounded at the southern end by the Merrimack schists. It begins
very narrow in Epping, — if that is to be regarded as the same area, — and
at Hampstead it is two and a half miles wide. Its course at first is
almost south, but changes to south-west in Windham and Pelham. It is
eight miles wide from Nashua to Dracut, across the strike, and ten miles
in breadth on the southern border of our map.

The eastern limit of the gneiss in Hampstead seems to be at the Con-
gregational church south of Wash pond, and a section across it to Derry
shows a monoclinal dip. At N. Hoyt's, half a mile from the church, the
dip is 50° N. 30° W., with beds of granite. Near the west line of the
town, on the first road north of Island pond, we find the same materials

GEOLOGY OF THE MERRIMACK DISTRICT. 56 1

dipping 85° N. 50° W. On the town line, at A. Ordway's, the dip is 70°
N. 40° W., and the beds of granite are noticeable for their large size.
For a few rods a south-east dip was noticed. On the west road it is at
least three miles before coming to the next observation, at Mrs. Black's,
dip 70° N. W. On a road farther south I noticed, near J. C, Drew's, very
abundant ledges on high bluffs, facing westward. Other ledges crop out
at H. N. Campbell's and R. Taylor's. Perhaps these dips diverge suffi-
ciently to authorize us to believe that there exists here an anticlinal axis.
There is more gneiss in the south-east part of Derry, said to be granitic,
and to dip N. 50° E. Passing through North Salem we find the same
rock standing on edge. At the school-house next D. Dunlap's the dip is
40° S. 60° E. Near Merrill & Bailey's factory the dip is vertical again.
At B. Foster's the direction is to N. 35° W. On reaching the westerly
branch of Spicket river we come to a narrow range of sienite, supposed
to extend beneath the village of Salem as far as I. T. Foster's, nearly
three miles. Fig. 93 embodies these observations through Salem in
graphic form. In the west edge of the village the gneiss dips 80° N. 75°
W. A coarse feldspar rock is interstratified with it at W. G. Crowell's,
two miles north-west. It is a coarse schist east of E. Sanders's, but far-
ther west the same gneiss dips 80° N. 50° W. North-west from Policy
pond are several exposures of the best defined Lake gneiss seen in this
neighborhood, dipping 85° N. 50° W. It is succeeded by a modern mica
schist beyond the school-house. These ledges are traversed by segregated
veins, and the series of outcrops just named represent a section across
the whole belt. The strata are more distinctly monoclinal here than in
Hampstead and Derry. West of the Salem depot are quarries of granite,
or rather of this gneiss, the dip being distinctly 50° N. 70° W. It
behaves just like the Concord granite in respect to its excavation. It is
traversed by the same vertical and nearly horizontal joints. There is a
cap of inferior rock over it also. This is at Gage's quarry. At B, A,
Cole's, a little to the east, the material is more granitic, and has large
masses of mica schists caught in it, in conjunction with large veins of
coarse granite. Passing westerly into Windham, on top of the hill a short
distance south-west from Policy pond, is a ledge of dark, fine-grained
gneiss, dipping north-west. Farther along are mica schists, holding a
similar position, at the south end of Corbett's pond. At the centre of
VOL, II, 71

562 STRATIGRAPHICAL GEOLOGY.

Windham the gneiss dips north-west, and is speedily followed by a simi-
larly inclined mica schist of the newer series.

Upon Section I this formation assumes the anticlinal form. The
western edge of the gneiss dips 50° N. 30° W. in the west part of Hud-
son. Near the east line it is incHned 85° N. 35° W., changing very soon
to S. 35° E., and just in the edge of Pelham, 87° S. 50° E. There is
a very fine exposure of gneiss, 75° S. 55° E., west of Compass pond. It
is followed by ledges of intermingled gneiss and granite, and by porphy-
ritic gneiss a little more than a mile south-west from Pelham village.
The granite of this town is like that of Salem, a stratified gneiss, with
some porphyritic crystals in it. After passing a wide alluvial tract, —
Beaver creek, — we find granites and slaty layers dipping north-west. For
two or three miles on the section line the dips are concealed.

In the south-east part of Nashua are various gneisses not fully charac-
teristic of the formation. They are seen on the road nearest the state
line, about a mile back of the Merrimack, with a vertical vein of granite
one foot thick. They dip about 70° S. 20° E. The strata are much con-
torted. Near M. F. Sawyer's, a mile farther west, they dip 70° N. 50° W.
This is their western limit, save as they may be buried beneath drift.
This corner of the town shows us an anticlinal in the gneiss.

We conclude there must be at least one anticlinal in this range, and
perhaps other folds. It is so well developed in Hudson and Pelham that
it is easy to believe it continues to the monoclinal section in Salem, and
the presumed anticlinal in Hampstead. The Merrimack group lies upon
both sides of it. Our studies of Massachusetts rocks lead us to call
gneisses very similar to this band, — and, in fact, the repetition of this one
beneath the Merrimack synclinal, — Laurentian. Should the Lake and
Laurentian series prove identical with each other, it would not be strange.

The small area of similar gneisses and granites in Nashua may be the
same with this Pelham range. That follows the Nashua river from the
city to the state line, and perhaps further. It is quarried extensively a
short distance beyond the city cemetery. There is a fine opportunity at
the quarry to observe the strata. On the south wall there is a change of
color, one shade showing distinctly strata dipping 80° S. 35° E., and the
other simulating the granite stone. The latter seems to be the more
highly prized by the quarrymen. There appears to be little other change

GEOLOGY OF THE MERRIMACK DISTRICT. 563

between these masses save in the color. Both sets of joints occur here,
as in the regular Concord granite. Of the minor features of interest, I
observed a good case of slickcnsidcs, where one part has slid over another,
affording a smoothed plane of contact, and small veins of translucent
quartz. Ledges of gneiss are found farther south-west, dipping S. 40° E.
There is a porphyritic mica schist with gneiss at the crossing of the
Nashua river, in the south-east corner of Hollis. The extreme north-east
and south-west limits of this area are unknown, on account of the great
profusion of sand and gravel in the Nashua and Merrimack valleys.

3. MONTALBAN SeRIES.

There are three principal areas of the Montalban rocks in the Merri-
mack district, and certainly three smaller patches. The three larger ones
are disposed like basins. The first lies in the Pemigewasset valley, com-
mencing in Lincoln in the White Mountain district, and extending south
to Salisbury. It is connected with our second area, extending from
Boscawen to Winnipiseogee lake ; but that is spoken of separately, on
account of its great divergence from the first. The third is the largest of
all, extending from the west corner of Barnstead south-westerly to the
edge of Goffstown and Weare. It is twenty-five miles long and nine
miles wide, oval in shape. There is a small area of this rock in Antrim,
and a little known expanse in New Ipswich. There is a third in Warner
and Webster.

The Pemigewasset area. This is fifty-five miles long. It starts on
the east flank of Mt. Kinsman, increases in width to the north part of
Thornton, and then suddenly doubles in size, being divided into two
parts by a narrow range of porphyritic gneiss, which keeps close to
the Pemigewasset river as far as Campton. The range is eleven miles
wide in Campton. It narrows at Ashland to four miles, being covered
up by the fibrolite variety of mica schist, possibly a member of the Mont-
alban series, carrying the gigantic veins of granite. The same width is
attained that we saw in Campton after passing the fibrolite schist. This
is continuous to Hill, where the narrowing, on account of the northward
extension of the Kearsarge andalusite group, and the westward hedg-
ing of the Sanbornton schists, amounts to three and two tenths miles.
From Franklin there is a broad spur, extending to the south-west into

564 STRATIGRAPHICAL GEOLOGY.

Andover and Salisbury, upon the south-east side of the Kearsarge rocks.
This is hmited southerly by the Salisbury area of Lake gneiss already
described. That part of the area in the Merrimack valley north of Con-
cord may be regarded as belonging either to this or the next basin.

The facts concerning this area above Campton have been set forth
upon pages 133-136. It would appear that the eastern portion of the
mass has generally the disposition of a synclinal basin, and that the
strike does not conform to that of the adjacent porphyritic gneiss.
Nothing is said about the exposures west of the river in Woodstock
and Campton. A portion of those in Woodstock are with difficulty
separable from the Lake gneiss. About half a mile south-east of Elbow
pond the dip is 80° S. 30° E. The rock is much contorted. The dip is
S. 85° E. by J. Downing's, in the south part of the town. At Hubbard
pond the dip is 75° N. 35° W. For about two miles through the middle
of the town, next the river, the rock is a wrinkled andalusite schist, like
that in Rumney. I have no observations relating to the occurrence of
this rock in Thornton, west of the river, but from what has been stated
it seems probable that the synclinal from the east passes near Hubbard
pond towards Rumney.

The position of the rocks across Campton is portrayed in the delinea-
tion of Section VH. The first rocks west of the porphyritic gneiss dip
north-west; — as N. 60° W. in the south-east corner of Thornton, and 35°
N, 30° W. on the summit of Mt. Weetamoo. At the base of the moun-
tain the dip changes so as to produce a synclinal. This position is con-
tinuous through to the river, giving us probably two foldings. Here is an
axis of porphyritic gneiss. On the first considerable hill west the dip is
southerly. This dip is so nearly like that in the east part of the town
that the axis is truly an inverted one. Near the west line the dip is 70°
N. 82° E., so that we have a synclinal here resting upon the older gneiss.
The character of the rock in the north-west projection of the town may be
known by stating the nature of the ledges proceeding south-westerly from
Bald hill to Rumney. At M. Cram's and W. Leavitt's is a mixture of fine
and coarse granites interstratified with the more micaceous layers, dip-
ping 30° E. At R. Pike's, in the edge of Rumney (or the school-house
south), the granite seams dip three degrees southerly. At L Chapman's,
more than a mile east of Rumney village, is the Concord granite variety.

GEOLOGY OF THE MERRIMACK DISTRICT. 565

At E. Blodgett's, in the south-east corner of the town, is an east dip.
These are all characteristic Montalban outcrops.

It would not be surprising if the andalusite mica schist of the north
end of Stinson mountain were identical with the similar rocks in Ells-
worth (page 472), and also with related layers in the central parts of
Woodstock. The Montalban of Mt. Weetamoo is now represented as
connecting directly with that composing the greater part of Sandwich
Dome, heretofore marked as an outlier (Plate XII). The granite of the
south-west corner of the town is more or less connected with the Rumney
and Plymouth area (pages 509, 510). At the high bridge over the Pemi-
gewasset at the south town line, and at the village on Beebe river, there
are ferruginous schists with high south-east dips. Mt. Prospect, in the
north part of Holderness, is mostly of porphyritic gneiss interstratified
with highly ferruginous schists, dipping N. 60° W. There is therefore a
synclinal axis between Prospect mountain and Campton. Specimens of
Montalban rocks have been obtained along Beebe river, east of Mrs. J.
Leavitt's, N. B. Crowell's, and at the fork of the road leading northerly.
Close by the east line of the town the dip is 57° N. 24° W. The same is
true respecting the south-west slope of Morgan mountain. Perch pond, and
at W. Brown's, in the south-east part of Campton, along the higher part of
Ryan's brook. Ledges occur at Plymouth village, and to the west and
south, one of them dipping 40° S. 60° E. In the west part of Plymouth
there is a small area of Lake gneiss, brought to light since the printing of
the pages previous to this one. At C. W. Nelson's and S. Morse's this
rock appears, with an east dip. At C. Nutting's, south of school-house
No. 10, a ferruginous schist dips 65° W. We find chiefly ferruginous
mica schist between Plymouth and Squam lake, with westerly dips. At
the town-house on the north side of Little Squam lake, a quartzose schist
dips 70° N. 64° W. East of school-house No. 2 of the old town of Hol-
derness is a ledge of quartz like that described in Hillsborough county.
The line of Section VI, passing through Ashland, Bridgewater, and the
south part of Plymouth, represents westerly dips to Bridgewater, and
then the reverse, enabling us to state the presence of a synclinal axis on
this route. The similarity between the ferruginous schists belonging to
the porphyritic and the Montalban groups in Holderness, Ashland, Ply-
mouth, Campton, etc., produces trouble when attempting to assign the

566 STRATIGRAPHICAL GEOLOGY.

several outcrops to their proper places. Near the outlet of Newfound
lake is a fine-grained gneiss, dipping 80° S. 68° E., and also vertical. On
a hill west an andalusite schist dips 75° S. 65° E. Near E. Woodbury's,
in Hebron, near the lake and south of the section line, a Montalban rock
dips 70° S. 60° E. In Bridgewater, fibrolite schist crops out at N. Chap-
man's, a mile and a half east of a bay in the lake. At S. and N. Brown's
is a pyritiferous schist. The same rock near S. Fifield's dips 74° N. 50°
W. At J. C. Barrett's the dip is 70° S. 85° E.

The following rocks were observed in the road from Danbury to Bris-
tol, down the valley of Smith's river. Porphyritic gneiss extends for a
mile east of the station to its junction with a hard micaceous quartzite,
dipping with it 80° S. 70° E. The river valley expands greatly in the
east part of the town, covering the ledges with low marshes and meadows,
the filling up of a former lake basin. There is a mica schist by T. H.
Danforth's, on the east side of the river. Near it, on the north side, the
dip is 35° N. 40° W., and the rock carries andalusite. At C. W. Buttrick's
and H. S. Clifford's, in the south corner of Alexandria, are fine-grained
gneisses, clearly Montalban in type. The dips are 60° N. 60° W., and 65"
S. 60° E. Near M. Gordon's are sihceous and ferruginous mica schists,
dipping irregularly 80° W. At school-house No. 2 is a distinct gneiss,
dipping 65° N. 30° E. Very near it, at J. Tilton's, the rock becomes
ferruginous, and dips north of west. Between the corner of Alexandria
and Bristol village, extensive sand deposits cover the ledges. At Bris-
tol we find mica schists, somewhat rusty. Following up the Pemi-
gewasset river from Bristol village, we see ledges of similar character at
G. Ingalls's and H. M. Emmons's, dipping N, 63° W. The position and
material are the same at school-house No. 4, and close by the river at P.
E. Heath's, and the rock contains andalusite. At the line between Bristol
and Bridgewater, a hard siliceous rock dips 80° S. 50° E. There are
several other ledges like it in the next three miles up the river, on the
west side. At the bridge leading to Ashland there is a gneiss dipping
63° W. This line of travel has revealed a synclinal in the east part of
Danbury, an anticlinal in the south part of Alexandria, a synclinal near
the east line of the same town, and an anticlinal in Bridgewater. Perhaps
the last is the same that occurs near the New Hampton bridge.

We have indicated an anticlinal line from the neighborhood of Plymouth

GEOLOGY OF THE MERRIMACK DISTRICT. 56/

village nearly due south to the Bridgewater boundary, a mile and a half
west of the Pemigewasset ; then it continues in the same direction along
the Bridgewater hills towards Peaked hill in Bristol. It may pass through
Bristol to connect with the anticlinal at a school-house in the south-east
part of Alexandria. The one along the river in Bridgewater and New
Hampton may be parallel. Fig 95 shows the relations of some of these
axes to each other.

In Alexandria, at Lamore and Berry's saw-mill, the dip is 50° E. ; near
Mrs. L. Gale's it is 49° S. 6" E. At the mill and school-house No. 6
above, is the east limit of the porphyritic gneiss. There is a patch of
vertical schists in the north-west part of the town, in the great basin
above H. J. Welton's, and lying upon the porphyritic gneiss. At Bristol
village the rock is largely ferruginous, but at the south end of Newfound
lake it is light-colored and compact.

In New Hampton the most northern outcrop of andalusite schist is
on the top of the hill south-west from C. Smith's, and over an interest-
ing glacial clay. The dip is 35°-4S° W. The same rock, with a similar
position, occurs in several other places in this town on the north-west
side of the porphyritic gneiss. At the north end of Shingle-Camp hill
it is much contorted, nearly vertical, with strike N. 30° E. The ledge
near the bridge over the Pemigewasset dips 50° S. 70° E. It is gneissic
in character, dipping 45° southerly, just before coming to Spectacle pond,
on the town line towaVds Meredith. At the south end of the pond the
schist is ferruginous, and dips more westerly. In the edge of Sanborn-
ton the dip is to the north-west. East from this point is the south-east
dipping gneiss of Cawley pond. From New Hampton village to the
crest of high land between Burleigh and Hussey mountains, drift prevails ;
but mica schist and gneiss occur near J, Merrick's, dipping 45° W. Fol-
lowing what was once a road from here to Cawley pond, I found, on the
Sanbornton line, mica schist, dipping 50° N. 50° W. At C. Emerson's,
the rocks are horizontal or dip 5° N. W., and hold some gneissic layers.
Next the gneissic layers prevail altogether, dipping 50° S. 75° W. South
of S. J. Dearborn's the schists dip 60° N. 60° W., occurring in high
embossed exposures. At S. Brown's the material is mostly siliceous.
Parts of it may be feldspathic, and approach the Concord granite in
character. This adjoins the supposed gneiss near Cawley pond, dipping

568 STRATIGRAPHICAL GEOLOGY.

north-west. These facts are embodied in Fig. 96. Sanbornton mountain
has not been visited, but it is supposed to consist of mica schists. On the
north side of White Oak hill, near Bristol village, the same schists dip
south-east. Ledges are abundant on the high hills opposite Hill, but they
have not been examined. In Hill the rocks are mostly mica schists.
Two miles west of the village, at a fall in Flanders's brook, the dip is to
the south. At the town-house the schists become ferruginous, and dip
south-east. The hills to the north-west seem to possess the same char-
acter. No other ledges appear in proceeding south-west from the town-
house till we come to the Kearsarge schists in Andover.

In Franklin, a mile and a half south of the Hill line, the schists dip 50°
S. 40° E. At J. W. Simonds's is a local anticlinal, the dips being 80° N.
70° W. and 80° S. 50° E. This is at an angle in the valley, the rock
crowding the river easterly. This axis is continued at S. G. Pike's, a mile
to the south-west. Near the town farm the rock is gneissic, and has been
quarried. Beyond H. N. Ingalls's the dip is 60° S. 25° E. At S. Judkins's
the rock is garnetiferous, and dips 80° S. 15° E. The dip is the same in
a gneissic rock a quarter of a mile to the west, above the sand. There are
many embossed ledges of these rocks in the north-east part of Franklin.
The structure of the Andover spur of Montalban may be learned from an
examination of the positions along Section V. At the village the dip is
80° S. 50° E. At A. and J. E. Colby's it is 80° S. 30° E. At the south
end of the Webster lake it is 50° S. 30'' E. It is 65° S. 30° W. at P.
Garrily's. The ridge west, in Andover, is covered by drift. These ledges
might be the northward continuation of the Salisbury gneiss, unless that
line is indicated by the Webster lake anticlinal. At the crossing of the
railroad by M. M. and P. Durgin's, the dip is 65° S. 40° W. West of
Horseshoe pond the dip is 70° W., the rock being ferruginous. Per-
haps this may be regarded as the western limit of the Montalban rocks.
So nearly alike are the mica schists of the different groups that no satisfac-
tory line of demarcation can be drawn, with our present limited knowl-
edge. Near the south line of the town the high hill east of Bradley pond
is a synclinal of ferruginous and other schists. On the north side the dip
is S. 17° E., and in the opposite direction, on the south side, the north-
ern dip being much the steepest. The lower part of the hill is composed
of gneiss. At the town hue the schists arc ferruginous. The schists a

GEOLOGY OF THE MERRIMACK DISTRICT. 569

mile south of Horseshoe pond dip north-west. Near the town Hne, along
the Blackwatcr river, are micaceous and ferruginous schists, dipping 75°
N. 85° W.

We may regard the anticlinal line by Webster lake as produced by the
presence underneath of the Salisbury gneiss ; — hence, in connection with
the development of that older rock in Salisbury to the south, and San-
bornton to the north, we observe a natural boundary between the Pemi-
gewasset basin and the area following the valley of Winnipiseogee river
to the lake. It will be noticed that this axial line points to the area of
Lake gneiss extending southerly from Squam lake in Center Harbor and
Meredith.

Winnipiseogee River Range. This may be regarded as starting in
Gilford and terminating in Boscawen. It touches the lake south of
Sanborn's point. Near H. Hunt's, back upon the highest land near the
point, is ferruginous schist dipping high S. 85° E. There are micaceous
schists on a high hill south from L. Gove's, nearly two miles east from
Lake Village, dipping 5o°-6o° S. 80° E. The layers are minutely con-
torted. Half a mile east of Lily pond, near M. C. Dexter's, a very fer-
ruginous schist dips 45° N. 60° E. A mile back from Laconia village,
towards Saltmarsh pond, the rock dips 25° S. 20° W. Just back of Lake
Village there are several outcrops of schists, containing a few garnets
and stauroHtes, dipping 75°-8o° S. 40° E. At the south end of Lake
Village, the white looking rocks are of andalusite gneiss, dipping lo^-so"
S. 65° E. On top of the hill behind them the dip is 80° E. At the fork
in the road by J. Davis's, a mile south of the village post-office, the dip is
south-west ; so that there must be a synclinal or a fault here between
the two villages. Lake and Laconia. At J. M. Weeks's, at the west foot
of the northern Gunstock peak, the gneiss dips 50° S. At J. B. Morrill's
there is a north dip, the ledges about here being considerably distorted.
There are schists at Gilford village. Between Long bay and Round bay,
in Laconia, are ledges of mica and ferruginous schists, dipping 7o°-8o° N.
50° E., minutely contorted. A little east of the jail, between Round and
Great bays, is a gneiss dipping southerly. North of K. Hall's, near the
south line of Gilford, are ferruginous schists with the strike N. 60° E.
This is thought to be continuous to ledges of quartzite, ferruginous schist,
and granites near R. Randlett's and the cemetery in the north part of
VOL. II. 72

570 STRATIGRAPHICAL GEOLOGY.

Belmont, dipping S. io° W., also W. and 12° N. 10° E. At the cross
roads, nearly to the west, the dip is S. 10° W. There is a white gneiss
running easterly at R. Rowe's, just in the edge of Gilford, to the south-
east of K. Hall's. The northern part of Belmont is universally covered
with ferruginous debris. Between J. Sawyer's and P. Folsom's is an
anticlinal with low dips. Near Sawyer's is a large ledge of gneiss. At
the north-east corner of Belmont, at the south end of the Belknap moun-
tains ridge, are ledges of ferruginous schist, dipping 10° N. 5° E., overlaid
by a hard gneiss, of texture like that of Concord granite, A few rods
to the east, in Gilmanton, the dip is 60° S. W., and the hill south seems
to be composed of the same material. At the north edge of the schists
next the sienite the indurated layers dip 80° N. 35° W. The line of Sec-
tion V runs through the south part of Belmont, and the rocks there are
probably of the newer age of mica schists.

Diligent search has been made in vain for a range of white quartz,
similar to that of Hooksett, in Belmont, Gilford, and Laconia, Boulders
of large size are scattered over these towns. They seem to be most
abundant on the ridge two or three miles back from Laconia village, but
extend as far as to the modified drift close by the houses. None are found
on the north side of the river. Hence the conclusion is reached that
the source of the fragments must be beneath the alluvium of Winnipi-
seogee river in Laconia and Gilford. That gives us a range of quartz in
the Montalban, just as we had a relic of it in the Pemigewasset basin
in Holderness.

The data for the delineation of these rocks in Sanbornton, Tilton,
Northfield, and East Franklin are unsatisfactory. Li the south-west part
of Franklin, half a mile back from the river, the dips are to the north-
west. Along the line next the Salisbury gneiss there is a hard quartzite,
with unsatisfactory dip. In Boscawen, at the north end of the village, are
rocks like Concord granite, with a north-west dip. The same occur near
Mrs. P. Arcy's, dipping 60° E.

The Concord area. This extends from Barnstead to Dunbarton, and
is noted for the presence of the well known granite of our capital. The
Concord granite seems to form two contiguous oval bunches, very much
like the smaller ones along the Manchester range, mentioned heretofore,
and a little more than eight miles in length. The best known portion

GEOLOGY OF THE MERRIMACK DISTRICT, 5/1

is upon Rattlesnake hill, where it has been extensively quarried. The
south-western limit is placed in the south-west corner of the town of
Concord. It is exposed at the cross-roads east of Great Turkey pond,
east of the smaller one, and from Millville across to the western limits of
the thickly settled district near the Asylum pond. A massive gneiss
flanks it on the west, at Millville. It crops out west of the railroad, in
the south-east part of the town, with north-westerly dipping seams ; and
occasionally in the city proper, as seen in the excavations for laying
the water-pipes on Tremont street, near the state prison. On the road
to Penacook lake the ledges crop out just beyond the sharp southerly
turn of the road half a mile west from Horseshoe pond. Near Little
pond the same kind of ledges seem to run N. 20° E. The southward
continuation of these rocks is quarried near W. M. Fox's, where the most
prominent seams dip 80° S, 70° E. In the other direction the rocks
continue into the hill, where most of the quarrying is done, and the same
ledge continues through to West Concord. West of Penacook lake is a
ridge of ferruginous rock with quartz. There seems to be a recurrence
of the Concord granite, or something very much like it, on the north-west
continuation of Pine hill, near A. C. Carter's ; and there are white ledges
between L. F. Ferrin's and the bend in the Concord & Claremont Rail-
road. This mass has not been observed for more than two miles in length,
unless the unusual prevalence of boulders of this material indicates out-
crops near D. Dimond's. At Contoocookville is still another mass of
Concord granite, perhaps a mile long. It does not appear to advantage
upon the map, on account of the overlying alluvium.

At A. A. Blanchard's, beyond West Concord, the rock is more gneissic
in appearance, dipping south-east, and must constitute the outer edge of
the granite. On the east side of the Merrimack, all the ledges seen north
of East Concord are of different character, but the granite makes up the
mass of some hills in the west edge of Loudon, The immense sand plain
of eastern Concord prevents us from knowing whether the granite is con-
tinuous beneath it from the city to Loudon village, the presumption being
against a connection.

The most extensive quartz range known in the Montalban runs through
Concord. It may be known first at the south-east corner of Warner, in the
small area noticed there on page 534. More likely there is a synclinal

572 STRATIGRAPIIICAL GEOLOGY.

between the two localities, occupied by the later ferruginous group. It is
first seen in Concord, at Pine hill, on the west side of Penacook lake. One
would expect to see it on Jerry hill, farther south, but we cannot find any
trace of it there. It dips north-west, and comes up again by I. Rowell's,
at the north end of the lake. At the first railroad cut beyond West Con-
cord it is certainly fifty feet wide. It is then concealed by alluvium, and
comes to view magnificently upon Oak hill, on the east side of the Merri-
mack, extending into Loudon. It is more than two hundred feet wide.
Search for the range farther east has not developed any other exposures,
but our explorations have not been sufficiently exhaustive to cover all the
territory. From miners' reports it would seem as if it cropped out again
to the east of Loudon village.

At the railroad bend two miles from West Concord are gneisses and
ferruginous layers dipping 65° N. W., and it looks like the still older Lake
gneiss with segregated veins a mile south of Horse hill. Near Sewall's
falls the gneiss with protrusive granite veins dips north-west. Hence
there is an anticlinal between, the falls and Blanchard's. On the Moun-
tain Farm hill the dip is north-west. At Snow pond it is the same. At
I. and J. Chase's, east of Hothole pond, Loudon, are coarse mica schists,
dipping north-west. The dip is south-east at the north end of Pleasant
street, and farther south the strike is nearly east and west. At J. C.
Eastman's and J. S. Ordway's the schists carry coarse granite beds with
north-west dips. At J. C. Sanborn's, on the continuation of Pleasant
street, west of Rollins pond, is a white gneiss, very much twisted, dipping
west. On the east side of Beauty pond, in the west corner of Barnstead,
there is considerable coarse Concord granite, and this is the most north-
eastern outcrop known in this Montalban area. The system is developed
farther to the north-east, in the coast district, after passing the overlying
mica schists of Barnstead and Alton. The ordinary coarse granites and
schists of this region crop out abundantly in the north corner of Pem-
broke and through Chichester, dipping north-west. On the west side of
the Merrimack they constitute most of the towns of Bow and Dunbarton,
being the natural continuation of the ledges in Pembroke and Chichester.

On a trip from Hooksett to Hopkinton, through the middle of Bow, I
found gneiss and coarse granite dipping north-west for some ways past
Bow centre. The south-cast dip is first prominent in the south-west

GEOLOGY OF THE MERRIMACK DISTRICT. 573

corner of Concord. The rocks seen on the river road through the town
between Concord and Hooksett may be described in the same language.
In the south part of Dunbarton and Bow the successive portions will
run along the course of Section III. The dips are N. 60'^ W. south of
Dunbarton centre, as far as Kimball pond, where there is a change to the
south-east, in a ferruginous rock. The south-east dip ensuing continues
through the rest of Dunbarton and Bow to Hooksett, to the edge of the
Lake gneiss. The strata dip so high that there is room for one or more
inversions, and there seems to be a sharp synclinal fold on the east line
of Bow. I have noted a possible N. 80"" W. dip near T, Johnson's, in
Dunbarton, south-east from Kimball's pond, in a long ridge of bare rock.
It is followed a mile south by a similarly inclined quartz.

Small areas of Montalban rocks occur also in Antrim and Warner,
together with the ferruginous tracts in New Ipswich and Deering.

/\. Ferruginous Schists.

Three of the designations mentioned at the outset are highly ferrugi-
nous : first, portions of the porphyritic gneiss ; second, of the Montalban ;
third, the Rockingham mica schist. These rocks may carry six or seven
per cent, of red peroxide of iron, and impart a rusty color to all the
ledges and the soil for hundreds of square miles. The basis of the rock is
twofold : sometimes a nearly pure gray quartzite, full of pyrites, which by
decomposition displays to us the rusty colored ledges ; and, again, a mica
schist, coarsely grained, probably containing the same compound of iron.
Iron is not a mineral that would enable us to use the fact of the presence
of a small percentage of it as a satisfactory criterion of geological classifi-
cation. But in exploring, one finds it nearly impossible to separate the
several ferruginous areas from one another. The ledges rarely show them-
selves free from decomposition. The region is not attractiv^e through
the great fertility of the soil, and one is inclined to dispose of any question
concerning them in the most rapid way possible. The large area in the
south-west part of Hillsborough county may be set down as Montalban,
and it is represented upon the map by some appropriate modification of
that color. It occupies an equally important area in Cheshire county, and
is there described as belonging to the Montalban series, page 489. The
rocks of the Montalban group in Bridgewater, Bristol, Alexandria, etc.,

574 STRATIGRAPHICAL GEOLOGY.

are as fully ferruginous as those in New Ipswich and Sharon, but have
not been separated from the others upon the map. Between the ferrugi-
nous portions of the Rockingham and Merrimack groups it is still more
difficult to draw a satisfactory line of distinction.

The following notes may express the nature of the rocks across the
patch of ferruginous Montalban in New Ipswich. At the south edge of
Greenville are gneisses of an older period, dipping 25° W. At the cross-
ing of the Souhegan, by a factory, ferruginous schists hold granite beds,
dipping 40° N. 80° W. Taking the road to Factory village, coarse, dark
mica schists appear. At M. Farrar's, on the north road to New Ipswich,
are Montalban schists, dipping 28° N. 50° W. Half a mile south of the
hay-scales a mica schist with granite veins dips 35° W. The same rocks
occur farther south, at G. Willard's, with the same position. Taking
first a line to the south-west corner of the town, we find ferruginous
schists at the chair-shop pond. East of the summit of the mountain is a
dip of N. 25° E.; and a crumpled gneiss on the ridge, perhaps dipping
west, as a similar rock certainly does in the south-west corner of the
town, S. 40° W. irregularly. Returning to New Ipswich village we find
mica schist with granitic beds, both somewhat ferruginous. It is thick-
bedded, dipping 20° N. 85° W. in the outskirts of the village. By S. C.
Wheeler's there is a ferruginous schist, dipping 20° E. This is some-
what local, though it may agree with the rock having the same dip on
the ridge near J. Nutting's to the south, just mentioned, and to the dip
of N. 85° E., at the south end of Kidder mountain, to the north. At W.
Shattuck's it is the same. On reaching the ridge of Barrett mountain
the dip changes to 40° W. This is continuous for over a mile. Near
G. Stratton's, half a mile before reaching the west town line, the dip
has changed to 15° E. It is higher in the east part of Rindge, and soon
makes an anticlinal axis. It will be interesting to compare this section
delineated in Fig. 94 with that about five miles to the north, in Fig. 91.
On the line of Sharon, ferruginous rocks dip 80° N. 60° W. Similar
rocks occupy the whole of Sharon. It is conceived that Kidder, Temple,
Pack Monadnock, Pinnacle, and Lyndeborough mountains may be dis-
tinct from this group, and they will be spoken of as Rockingham schists.
I judge the ferruginous type of rock extends west of this into Greenfield.

The next ferruginous group of this age is that of Dcering, occupying

GEOLOGY OF THE MERRIMACK DISTRICT. 575

the country west of the Crotched mountain range of Lake gneiss. The
rock a mile south of the south-west corner of Deering, in Francestown,
dips 80° N. 60° W. On top of a high hill in the south-west part of Deer-
ing, near W. Wilson's, the rock is abundant, and dips 65° N. 50° W. At
J. O. Dinsmore's is a hard quartzite, dipping 80° S. 30° E. This gives us
an anticlinal, and there must be a synclinal to the east, before coming to
the westerly dipping Lake gneiss on Gregg's hill. Through central
Deering, along the route of Section III, are westerly dips of gneiss from
J. Downing's to S. Carr's, more than a mile west of Deering church.
They stand nearly vertical here, but dip 50° S. 80° E. half a mile west, at
I. McKean's. Hence we have a synclinal here, and this easterly dip is
continuous to the Contoocook river. Through the north part of Deering
the rocks dip very much, as along the section shown in Fig. 97. West
of J. B. Hall's is a hard, flinty rock, dipping 75° S. 80° E. At J. H.
Gould's, on top of a hill, the schists dip S. 65° E. On reaching the
valley by L Smith's, the same flinty rock dips 65° N. 50° W. Large
garnets sometimes occur with it, and many layers are ferruginous. A
mile east the ferruginous element is more abundant, the dip being the
same. West of the school-house by B. Gove's, the rock is as red as ferric
oxide ever occurs, with a north-east strike. There are some gneissic
layers in a similar rock, dipping 85° N. 75° W., on the town line. This
brings us nearly to the vertical layers of Lake gneiss in Weare. The
hills in the south part of Henniker are composed of mica schists of
different aspect and position, and therefore are not included in this area,
though the strike would naturally seem to include with it all the rocks
west of the gneissic range, as far as the notch made by alluvium along
the line of the old New Hampshire Central Railway.

Another ferruginous area, thought to be like these, lies in Hopkinton,
Concord, and Boscawen, apparently occupying the region beneath the
abundant alluvium of the Contoocook. It lies east of the narrow porphy-
ritic gneiss range in the east part of Hopkinton. They have the strike
N. 20° E., at S. Gale's, with easterly dips nearer the village. Nearer I.
Proctor's, in Concord, a mile west of Little Turkey pond, the dip is 80° W.
The old gneiss near Tyler's station, Hopkinton, joins a ferruginous rock
dipping 75° N. 65° E. West of J. Patch's the dip is 20'' N. 65° E., and it
may be as low as 10'^ in some exposures. The same style of very rusty

5/6 STRATIGRAPHICAL GEOLOGY.

rock covers the road east of Ash brook in Concord, and west of Jerry hill.
Between Jerry and Pine hills the dip is north-west. At the west base of
Horse hill, at Mast Yard station, the dip is 55° N. 65° W. By E. C.
Elliott's and Mrs. Eastman's the rocks are gneissic, dipping 75° N. 40°W.
By E. Terry's is a single lenticular ledge, eight feet long, of the same
material. Gneiss with north-west dip appears also by G. Colby's. Per-
haps the ferruginous rocks next, in Boscawen, should be included with a
later group, but everything in the village of Fisherville properly belongs
to this section. The rocks there are ferruginous gneisses, compact dark
schists, and fine- and coarse-bedded granites, all dipping north-west.

5. FiBROLiTE Group with Coarse Granite Veins.

This band of rock, carrying the best veins suitable for quarrying mica,
enters our field of description in Hebron and Plymouth, but I can add
nothing beyond what has already been said of them in Chapter V.

6. Rockingham Mica Schist.

This term was first used in the report for 1872 (Vol. I, page 55). It is
very convenient to designate a large mass of mica schists, with the mica
often in coarse blotches and the predominant mineral, by a geographical
reference until its proper geological place is known ; and therefore we
cannot yet dispense with the term. The closest resemblance is to the
micaceous portion of the Montalban series, specimens holding the coarse
mica being undistinguishable from many ledges among the White Moun-
tains. When large crystals of andalusite occur in the schists it is not
easy to distinguish them from the Kearsarge group. There is no diffi-
culty in discerning the relations of the formation to the Merrimack group,
yet the boundary line between them is not satisfactory. It is thought to
correspond with the mica schist division of the Coos group along the
Connecticut valley. When well filled with ferric oxide, the rock becomes
one of the varieties of the ferruginous division. It is better developed in
Strafford than in Rockingham county, but the necessity of separating the
group from everything else made itself manifest from the study of the
formation in the first named district.

Two features further characterize the group. First, bands of quartz
pass through it, as in some of the older series, before described ; second,

GEOLOGY OF THE MERRIMACK DISTRICT. 577

beds of granite are innumerable. They are often of sufficient conse-
quence to be specially colored upon the map. These two features show
how closely the formation imitates the Montalban. As regards elevation,
the strata are commonly inclined at small angles, with numerous local
foldings, and they constitute mountain masses when slightly inclined.
These characteristics agree with their reference to a comparatively mod-
ern period for their deposition. The grinding up of the Montalban strata
would furnish the materials for the recomposition of ledges very similar
to them, and at their junction the differences might be so slight as to pre-
vent a ready recognition of the discordances in stratigraphical structure.
It has been stated heretofore that this group is spread like a blanket
unconformably over several of the older gneissic groups. This statement
still seems to be correct. In our delineation of it in map No. 5 of the
physical history of the state, the color is made to embrace on the north-
west side the Kearsarge group and the fibrolite rock with coarse granite,
and on the south-east the Merrimack groups. A small area near Umba-
gog lake is also placed with it, which is reckoned as Huronian on the
final map.

In the Merrimack district the following areas of this rock will be noted :
(i) in Sanbornton ; (2) (3) branches of the enormous Strafford county
blanket, prominently occupying Canterbury and Northfield on the north,
and Allenstown and Epsom on the south ; (4) (5) at least two long
narrow bands between the quartzes of Hillsborough county ; (6) the
Lyndeborough and Temple mountain range ; (7) Mt. William in Weare ;
(8) that associated with the Merrimack group, between the Manchester
and Hampstead gneissic areas.

Sanbornton. This area touches the porphyritic gneiss and the Great
bay on the north-east, small patches of Lake gneiss on the north and
south, and Montalban on the south-west. It does not seem to cross
either the Winnipiseogee or Pemigewasset rivers, though reaching to the
banks of both streams. On the slope towards Great bay, the ledges are
mostly concealed by a sloping mass of drift. The granite of the series
appears north of O. Calef's. Going north from Tilton the boundary of
this group is reached at the "gulf," the dip changing abruptly to the
south-east instead of north-west. It changes back again a mile north of
the "Square," near W. Paine's, 60° N. 27° W., also 30° N. 60° W. The
VOL. II. 73

5/8 STRATIGRAPHICAL GEOLOGY.

dip sometimes descends to io°. At T. B. French's, beds of granite occur.
As far as E. F. Plummer's, ledges dip N. 60° W. The mica schist is red
at J. Flanders's, near the Meredith line. About the granitic rock, on the
high hill, the dip seems to be north-west, and to belong to this series
better than any other, though there is room for difference of opinion. At
J. & H. N. Marsh's, a mile west of the gulf, the dip is 80° N. 85° W., and
the ledges are common between this point and Tilton village, some of
them belonging to an older series. No further observations have been
recorded of dips in Tilton. The only points of interest ascertained are
the fact of the unconformable relations of the mica schist to the porphy-
ritic gneiss of Meredith, with an axis at the gulf. The strike of the
schists points square across the gneiss. In the north-west part of San-
bornton the dips are mostly to the north-west. The relations of the
several rocks across this area are shown in Fig. 96. It starts near the
Pemigewasset river in Bristol, exhibits the anticlinal in that valley in the
Montalban series, then a synclinal hill, and mostly north-west inclinations
over the Sanbornton mountain ridge, and two ridges of gneiss, — the last
in the valley of the outlet of Cawley pond. After this follow the mica
schists with the same dip on the "Square" ridge, and the various gneisses
of Tilton and Northfield.

Canterbury, Northfield, etc. This north-western extremity of the blanket
occupies also portions of Belmont and Gilmanton, west of the eastern
boundary of the district. The relations of the rocks appear in a section
(Fig. 99) from Belmont to Lower Gilmanton. At Belmont occurs one of
the minor irregularities liable to be seen in any of our formations. The
average dip is south-westerly. There is evidence of a synclinal near the
town line, and it may be the same undulation with the shallow basin on
the north side of Little pond in the south corner of Belmont. South-east
from the pond is a large mass of coarse granite, considerable ferruginous
and other uncanny rocks. Through Gilmanton the dip is monoclinal,
north-westerly. The rock is ferruginous north-west from the centre
village, and also at the lower village, but not so between them. We find
the dip north-west on top of the hill, between Shell camp and Rocky
ponds. The Bean Hill area in Northjfield and Canterbury has considerable
granite in it. That near Little pond crops out again in the Pinnacle, —
possibly it is contiguous, — with the same north-west dip. There is a large

:Pi^^EXJcin.

F/G.B5. Through Alexandria and Bristol to N ew Hampton C£nt£:r.

/

N tJ^a u b a in . ^ ^

S "V R0CKINCHA.M 0

v"' SiuiharjitoaMt.JGdde. Mica Schist W a «^ o

* ^^^^^ -■ * P* RocKincHAM Mica Schist.

WMi/m/mMimm

F/G.S6, From Bristol to Northkield

Fig. 97. From North Deering Fig. 98. From Townsend to 6f<oTON,AlAss.

/NTO We A RE.

J?R O C K

N G^

^'

M i/c Ak

^^^^Mmsm^m// \-mmM.

FiG.SS. Through B elmont ano Gilmanton.

SC/\LS ^ HORIZONTALLY, 2^ MILES TO A/V INCH; VERTICALLY ,^00 FEET TO AN INCH.

GEOLOGY OF THE MERRIMACK DISTRICT, 579

vein of white quartz near Capt. T. Fellows's. The top of Bean hill is also
mostly coarse granite, with only enough ferruginous mica schist to indi-
cate the north-west or west pitch of the mass. The mica schist has the
same position at the north base of the hill. The dip is io° S. i8° W. on
the line between Belmont and Northfield, where a tributary of the Tioga
river crosses it. The long narrow ridge from Hill's corner to Shaker
Village is gneissic schist, with a small dip. Possibly it is an anticlinal.
The north part of Canterbury has not been explored.

Pittsficld, etc. In Pittsfield, Epsom, and Allenstown is the other
branch of the Strafford county area. At Pittsfield village the mica
schist dips south-west. At E. French's, a mile and a half south, we find
westerly dips, with small granite beds. On Catamount mountain granite
beds occur ; the dip is south-east, showing the presence of an anticlinal
axis. Near Webster's mills the railroad has cut through a ledge of
quartz similar to the bands that have been described above. The dip
is N. 75° W. On the east side are two hummocks of coarse granite, —
one of them seemingly cutting across mica schist, — dipping N. 30° W.
In Epsom the beds of granite are not uncommon, and they often carry
tourmaline. The dips along the Little Suncook river, near the east line
of the town, are north-westerly. There is an anticlinal in the south-west
corner of the town, in connection with some schists in Deerfield. Brush
hill, McKoy's, Fort, Nottingham, and Nat's mountains are composed of
these schists, and are supposed to dip north-west; but this is an impres-
sion from recollection only, not based upon recorded observations. In
Allenstown the ledges are not numerous, as deposits of drift are very
abundant.

Between the Quarts Bands. The sections in Figs. 87 to 91 cross nar-
row strips of this mica schist, and have been already described in detail.
The rock is closely allied to the Montalban schists. Two bands appear
on the map. The first lies chiefly in Goffstown, and runs between the
Uncanoonucs, being over six miles long. Possibly it should be extended
farther north-east, to include the low-dipping schists on the west line of
Hooksett. The other starts from the middle of Goffstown, and extends
to New Ipswich, through Bedford, Amherst, Mont Vernon, Lyndebor-
ough. Temple, and Wilton, a distance of twenty-three or twenty-four
miles. It is a trifle over a quarter of a mile wide at its north-east end,

580 STRATIGRAPHICAL GEOLOGY.

and gradually increases to nearly four in Temple and Wilton. The dip
is invariably north-westerly, and usually at a small angle. It forms a
sort of plateau through Mont Vernon. Roby hill, in the north-west part
of the town, is composed of mica schist. It crops out with a low, north-
westerly dip at A. J. Twiss's and B. Jones's, near a mill ; a mile north-
east from the village ; at the church, with granite ; near G. A. Wallace's,
on the Francestown road; near J. Hartshorn's, dip 15° N. W. ; near A.
Upton's, and elsewhere. At Purgatory falls, on the line of Mont Vernon
and Lyndeborough, the schists, with coarse granite beds, dip 50° N. 30°
W. In the north-east corner of Wilton the dip is small to the north-
west. This range is made to terminate in the north part of New Ipswich,
but it may possibly continue into Massachusetts, On the north-east it
points towards the Allenstown deposit, and may occupy the same depres-
sion with that or some portion of it.

Temple Mountain Range, The map shows a line of elevations from
Lyndeborough to New Ipswich, whose similar topographical features
suggest identity of geological character. The Lyndeborough mountains
rise abruptly from the comparatively flat ground of New Boston and
Francestown ; and the rocks change as quickly as the elevation. Gneiss
is exchanged for mica schist. We observed the following facts in cross-
ing from Francestown to the centre post-office : Irregularly curved mica
schists, like those holding andalusite, with westerly dip, on the Piscata-
quog river near the south line of Francestown ; at L. Spaulding's, a
mile farther, the mica schists dip north-west at a small angle ; on the
summit of the ridge the dip is 50° N. 20° W.; and the same rock extends
nearly to the centre village. Loose blocks of the schist hold excellent
specimens of the long, fibrous mineral andalusite or fibrolite, showing
that it characterizes the deposit, though not actually found in place.
Between the Pinnacle and Pack Monadnock mountains is a deep valley,
cut down by Stony brook, and the place where the railroad passes from
Wilton to Greenfield. For two miles or more, the mica schists are well
exposed along the axis of the mountain ranges. In the saddle between
Pack Monadnock and Temple mountain the schists dip 30° N. 50° W.
On the west side and summit of Temple mountain the rock is mica
schist, with granitic beds, dipping 8°-io° W. At the south end of Kid-
der mountain in New Ipswich, which is of the same material with the

GEOLOGY OF THE MERRIMACK DISTRICT. 581

Others mentioned, the dip is N. 85° E. A narrow band of rock has been
stated to continue southerly from this mountain to J. Nutting's, on the
east side of the Barrett Mountain range, a mile north of Massachusetts.
It may represent this formation. Barrett mountain, being more gneissic,
is thought to be older. Accepting the correctness of the identity of the
rocks of these several mountains, it would appear that the strata have
been pushed into an anticlinal form, while the dips are very small. This
range presents greater resemblances to the Monadnock rock than any of
the others described.

Mt. William. In Weare, Mts. William and Wallingford are composed
of this mica schist, dipping 70° N. 40° W.

T/ic Deny Range. This is the most important of all, since it stands
closely connected with the Merrimack group. It covers a greater area
on the Coast than the Merrimack district. Entering our field of descrip-
tion at Derry, it crosses into Nashua and Hollis, and then leaves the
state, being identical with the mica schist group crossing through Mas-
sachusetts past Lancaster, Sterling, and Worcester nearly to Connecticut.
The best idea of it, as it occurs in this district, may be gained from an
examination of a section through Derry (Fig. 100). The mica schist
adjoins gneiss in the south-east corner of Manchester, having a south-
easterly dip. Just in the edge of Londonderry is a feldspathic layer. A
band of white quartz, similar to others that have been prominently de-
scribed, crosses the section midway through the north-east corner of the
town, near a school-house. Other ledges of mica schist occur between
the school-house and the west line of Derry, dipping to the south-east.
Commencing with the Derry line, we find next a rock consisting of crys-
talline feldspar, extending, by measurement, two hundred and eighty rods
along the route of the section, dipping south-east. A few rods of it dip
north-west at the Upper Shields pond. Next follows a quartzite contain-
ing numerous segregated quartz bands or veins, dipping about 85° N.
30° W. Near W. Palmer's begins a series of regularly-bedded mica slates,
dipping 80° S. E. These extend as far as Beaver pond. The face of
the country varies according to the nature of the underlying rocks.
Over the feldspathic area the soil is barren ; but excellent farms cover
the slate area.

There is a feldspathic rock at Derry west village, with uncertain dip.

582 STRATIGRAPHICAL GEOLOGY.

A broad meadow conceals the ledges next, as far as the double road
around J. Patten's, where the mica schist changes to dip 45° N. W. The
angle of the dip here is much less than by Beaver pond. Next the mica
schists dip south-east at three localities, — the valley of West Run brook,
at J. Boynton's, and midway between them. This south-east series of
outcrops extends for a mile and a half. At J. Low's, north of Ezekiel
pond, mica schists dip 80° N. W. Just east of the pond succeed coarse
granites. The same occur at E. Hobbs's, on the south side of the pond,
dipping 75° N. 50° W. These rocks are chiefly porphyritic feldspars,
with hard mica schists, freshly exposed in a railroad cut. Along the
Lawrence railroad, west of Mitchell's pond, near the north line of Wind-
ham, similar schists and feldspathic rocks occur. Less than a mile south-
west from Mitchell's pond is a large amount of feldspathic rock. Farther
south, where small bends in the road are conspicuous, the feldspar beds
and mica schists alternate. We find granitic rock at D. Kelley's, schist
at T. Dinsmore's, and so on to the Lake gneiss, the last half mile of the
section being mostly devoid of granite. The last mile of the way shows
small bands of quartz, and there are enough large boulders of this material
on the surface to suggest the near proximity of a considerable bed of it.
The section suggests a general synclinal structure of the whole band, with
correspondences on the sides. We find the coarse feldspathic beds on
both sides, with the possibility of a quartz bed repeated. The central
portion is occupied by a slate, which may perhaps be traced south-
westerly to connect with the clay slate of the Worcester county, Mass.,
range. The mica schists are usually more siliceous than the majority of
the Rockingham schists in the other areas, but are not quite the same
with the micaceous quartzites of the Merrimack group. There is a mass
of Huronian aspect, however, in the north part of Derry, which requires
farther exploration before its relations are satisfactorily made out.

Section II crosses the formation transversely, and we glean the follow-
ing facts from it. From Derry station, on the Rochester railroad, to East
Derry, the dips are north-west, and the rocks mica schists. No ledges
occur anywhere about the village. Between this village and the eastern
town line a few ledges dip 70° N. W., and carry large granitic beds in
their eastern outcrops. Between Derry west village and the Lawrence
railroad depot are mica schists with north-west dip. West of the railroad

GEOLOGY OF THE MERRIMACK DISTRICT. 583

is the mica slate range coming across from the north side of Beaver pond,
dipping 70° N. 30° W. At the west town line they stand about vertical'.
The dip of 85° N. W. extends about half a mile into Londonderry. At
the cross-roads east of L. Welch's the first south-east dip is found. The
rock stands vertical at A. P. tiardy's and at the school-house. The dip is
south-east a mile north, at the Pinkerton cemetery. It is vertical at S.
Bancroft's. At the forks in the road by P. Crowcll's, a few layers of the
feldspathic sandstones begin to show themselves in the schists, dipping
high south-east. Between Crowell's and N. Chase's, hard blue schists
prevail. Along the Mammoth road east, back of J. Royce's, the white
ledges are very conspicuous. At D. Goodwin's an ancient appearing
mica schist dips 80° N. 60° W., also at N. Boye's. At F. Coming's the
rock dips south-east, and at the cemetery near by the schist is somewhat
ferruginous. This is the last ledge seen on the line of the section, and is
a mile and a half east from the Litchfield line. The river sand now con-
ceals everything to the river. This gives us the main synclinal and two
subordinate axes along this route, and the feldspathic beds near the bor-
ders as before.

A few other facts in Londonderry are these. On the Mammoth road
the feldspathic beds begin just north of the railroad crossing. A little
south are the mica schists, which may be followed north-east to cross the
railroad again by Wilson's station, and appearing on Fig. 100, south from
the quartz band, a distance of four miles. Next is a feldspathic band
beginning south-west, to the south of Cyrus Nesmith's, dipping S. 45° E.,
appearing east of the Mammoth road, north of J. Brickett's, and so on to
its place on Fig. 100. The next schist band is seen about a Baptist
church, and farther south-west, north of J. Dickey's, and so on towards
Scabies pond. There is a still more prominent feldspathic band adjoin-
ing this, — from L Kimball's, in the west part of the town, to the east of
the Mammoth road, by J. Royce's, and at Moore & Perkins's. Almost all
these outcrops dip south-east. To the south of this last named white
band are no feldspathic layers of any account on the north side of the
synclinal line. Numerous quartz boulders near A. Smith's, east of I.
Kimball's, suggest the near occurrence of the ledge. Drift is more abun-
dant in the middle of the town, but there are north-westerly dipping out-
crops at the town-house and a mile west. There are other ledo-es of

584 STRATIGRAPHICAL GEOLOGY,

similar nature and position elsewhere in the south part of Londonderry
and the north part of Hudson. On the route from Windham town hall
across to Nashua the following observations may be relied upon. The
schist first appears on the south-east edge of the formation, a mile west
of the hall, by J. Evans's, dipping north-westerly. There is a gneissic
appearing rock at the west town line, by a railroad station, and feldspathic
bands at Noah Robinson's and D. Clement's, in Hudson, with mica schists
between. Several other ledges occur on the route, all of them with north-
west dips. Under the bridge over Merrimack river micaceous grits dip
80° S. 30° E., and there must be a synclinal between the last two obser-
vations. The rocks in Nashua are more like the Merrimack group than
those in Derry. The reservoir rock, dipping 80° S. E., is an argillaceous
quartzite. This may be the southward continuation of the similar rocks
wdth slates at the drug mill, on the north line of Nashua, dipping south-
east. At an excavation in North Pine street is one of the feldspathic
bands, dipping 80° N. W., and carrying small oval patches of mica. Two
miles south of the post-office, at R. Godfrey's, mica schists dip 45° N. 33°
W. At the cemetery a mile north of the state line, next the Lowell rail-
road, the same rock dips 50° N. 20° W. A feldspathic band occurs a
mile north. Taking the route between the two gneiss areas to the
south-west, we find a hard mica schist with segregated veins at A. and C.
Lund's, dipping 75° S. E. Three miles out, on the Acton railroad, a cut
shows several varieties of mica and sandy schists, dipping 15° S. At L.
White's, near Lowell pond and the state line, is an unclean, coarse, ferru-
ginous mica schist, dipping 65° S. 60° E. Near S. Swallow's, feldspathic
mica schist dips S. 40° E. This section of the formation dips altogether
south-easterly.

The more argillaceous member occurs east of H. Wood's, near the
west line of the town and north of the Nashua river, dipping 85° S. 30°
E. At Terrill's, near the town farm of Hollis, it is more slaty, dipping
45° S. 50° E. Near Hollis centre similar ledges, jointed and micaceous,
dip 50° S. 40° E. Proctor hill, in the west part of the town, is composed
of mica schist — dip, 45° S. 70° E. — and a large protrusion of the granitic
layer. On the western slope of the hill the schists dip 55° S. 80° E.
This rock is believed to occupy the south-east part of Brookline. In the
north-west part of Nashua, at B. F. Colton's, the schist dips south-east,

GEOLOGY OF THE MERRIMACK DISTRICT. 585

and breaks naturally into prismatic fragments. The same is true of the
rocks at South Merrimack, with the addition of fine-grained feldspathic
beds. All the rocks in the south part of Merrimack dip to the south-
east.

A few statements will show how these rocks appear farther to the
south-west in Massachusetts. In the south part of Lunenburg, along the
Fitchburg railroad, is an exposure of a white quartz band, similar to the
one mentioned in Londonderry, having the strike N. io° E. A slate near
it dips irregularly to the south-east. Crossing from Townsend to Groton,
we find, first, gneiss, then mica schist with feldspathic beds dipping
45° E. In Shirley, the west part of Groton, and in Pepperell the rock is
argillaceous and slaty, dipping east. A mile north of Groton centre is
a bed of soapstone, in a jointed mica schist, dipping 25° S. 20°-30° E.
Near the north line of Ayer we find the regularly-jointed, coarse-bedded
gneiss, dipping 75° N. 20° W. Hence a section here indicates easterly-
dipping monoclinal strata resting in a synclinal of gneiss.

7. Kearsarge Andalusite Group.

The Monadnock area of andalusite rocks has been described in Chapter
V. A similar mass of strata occurs upon Mts. Kearsarge and Ragged,
constituting a band twelve miles long and from three to four wide, in the
towns of Warner, Sutton, Andover, and Salisbury. Starting from the
Warner side, the peculiar rocks of the mountain are first seen at Stanley's,
a quarter of a mile south of the toll-gate, standing perpendicular, with the
strike N. 30° E. The strata display large contortions, while the gneisses
below do not seem to have been greatly disturbed. I have often noticed
that the newer strata are usually the ones apparently showing the great-
est signs of pressure, but not necessarily crystalline. The older ones
may have lost the tokens of a greater action by metamorphism, but it
is certainly not apparent in the condition of foldings or faults. For this
reason I do not consider it a sure guide to antiquity among our forma-
tions, to affirm that the most disturbed are the oldest. Clearly these
schists are granitic masses, approximately similar to those so common
in the Rockingham country, and they continue until replaced by the fer-
ruginous schists at the toll-gate. These occur occasionally in climbing
the turnpike. On reaching "Plumbago point" these schists are vertical,
VOL. II. 74

586 STRATIGRAPHICAL GEOLOGY.

with the strike N. 70° E. The road started out to the north-east, but
after passing Pkmibago point it changes to north-west, passing along the
crest of the mountain, receiving the name "Mission ridge." The rock
is a hard, brittle, fine-grained granite. At its north end, near the "White
house," at the beginning of trees, the hard schists dip N. W. 85°. Large
veins of a porphyritic granite, a little like the Albany, appear next. A
quarter of a mile higher up this granite has planes dipping 50° W.
Others dip 10° S. Half way to the " Garden" quartzites dip 75° S. 62° E.
Further on they contain scattered crystals of andalusite, and dip east.
Near the Garden the dip is 50° N. 50° W. At the last abrupt turn in
the road the dip is N. 40° W. In the depression called the "crater" the
dip is 70° N. 52' W., the rock being mostly an andalusitic quartzite, in
strata resembling sandstone. On the very summit the dip is N. 35° W.
On descending to the Winslow house the dip veers more northerly. At
the top of the clearing below the woods, I measured dips S. 35° and 40° E.
At the hotel the dip is 80° N. 80° W. A quarter of a mile below this
house the dip is 85° E. There is a ledge of mica schist near the east line
of Wilmot, below the hotel. Taking another route down the north-east
side, in Andover, I found the dip becoming northerly ; also an interest-
ing curvature with a quartz vein, which is delineated in Fig. loi. The
ledge had been cut by a joint, leaving a nearly vertical smooth surface,
fifteen feet high and forty long, showing two curvatures. The axis of the
folds runs N. 42° E. The vein occupies a fissure where the rock had
been subjected to the most pressure. At the edge of the woods the dip
is 30° N. 18° W. Lower down are abundant crystals of andalusite two
inches long. Before reaching the lower edge of the forest the strata are
vertical, with the strike N. 50° E. At a saw-mill the dip is 85° N. 40° W.,
much andalusite being present. Nearly down to the road, parallel with
the west line of Andover, the dip is 75° S. 30° W., though more usually
N. 30° E. In a sort of meadow north of the "pyroligneous acid manu-
factory" of the county map, the rock resembles the Montalban schists,
crowded with foldings and inclined perhaps S. 80° E. Between Cilley-
ville and Potter Place a dark quartzite dips 70° N. 70° W., and the rock
is said to be plumbaginous. On the west side of Mt. Kearsarge in
Sutton, on an old road to S. S. Felch's, the mica schist dips 85° N. 80° W.
It lies next to porphyritic gneiss. The south-west and east sides of the

Tj^^^jejJCXIV,

R O c/ K I N^"" G Hb^ A . M M I C A ^ S C H I S T.

* >i- i' i'- ^ J ^'

^

'^Fei.osPATMtc Beds r ^\^ g

u mm SOME Schist. A' Lak e^'Gne iss. ^

FiG.JOO. Through Derry, ^c.,to Salem D epot.-Contwuation of Rg.92.

Yj2i nMLBS TO J\N INCH i V E ^T I C A, LLY , SOOO 1^ E E T To ^/v //VC«

SCAL.E , HORII-Or

^^ An OAiusir^ Mica Schist 1^ -^ ^

1-^^^ Granite. |-

Fig. lOl . Cur va tures in Sera ta,

15 f^££r HIGH J '4-0 rEET long.

FigJ02. Mr. Kearsarge.

HORfZ-Or^TAL SCALE , 2^ MILES To /\/V INCH.

V E ftTicA.1- " , 4rOOO Eter- - ./ .

G/

mrnMimmmm..

FiG.103. In Andover. FiG.l04r. From Hart's Saw-mill to West Base of

.2\

.es TO An ll^CH; VE KTIC ALt-Y , 3000 fEET TO At

^

m

t

K

llL.

G fN

i

\\hmmmmmmimMrmiMm/

Fjc J05. From Mad River to Wakefield Junction .

SCALE, HORIZONTALLY , 7k f^'t-ES TO AM INCH; VERTICALLY, 5 OOO FEET TO AH INCH.

GEOLOGY OF THE MERRIMACK DISTRICT. 587

mountain have not been explored. Fig. 102 embodies the observations
taken from Plumbago point across the summit to the Winslow house, and
so on to Wilmot Flat. I'he more elevated portion shows the presence of
two anticlinals and three synclinals, and the general attitude of the area is
synclinal, because it rests upon older rocks everywhere.

Fig. 103 exhibits the stratigraphical structure of the mass in a section
through Andover, following the Northern Railroad. It would be possible
to recognize the same folds here as in Fig. 102, though they are closely
pressed together. The rocks rise again to the north in Ragged mountain,
and we ascend from Andover centre. Half a mile before reaching the
last house (G. W. Thompson's), andalusite schists dip 70° N. 70° W. The
lines of ascent and descent taken may be from a quarter to a half mile
apart. On the more western one, six hundred and fifty feet above the
house, the rock is vertical, and dips 80° N. 40° W. Eight hundred feet
higher than the house the dip is 85° N. 40° W. On the summit the
andalusite flags show numerous small convolutions, as on Kearsarge, the
average position being 75°-8o° N. 40° W. On looking south-westerly,
the strike of the ledges points towards Mt. Sunapee instead of Kearsarge.
Should this direction prevail, it would indicate the repetition of the Kear-
sarge strata upon Ragged mountain, separated by an axial line. This
mountain is just as much isolated as Kearsarge. The summit is in three
parts, the eastern peak being the highest of all, perhaps twenty-five feet
above the middle eminence supporting the signal of the Geodetic Con-
nection Survey. The strata on the eastern line of descent agree nearly
with those seen in ascending. Near Thompson's the strike is N. 30° E.

The Ragged mountain ridge has been crossed between East Andover
and Hill. At the railroad curve, drift conceals the ledges. At L. Brown's,
after beginning the ascent, the strata dip high to the north-west. At B.
Tucker's are a few ferruginous layers. On top of the ridge the strata dip
80° N. 70° W. On reaching the town line, hard andalusite sandstones
and feldspathic beds occur, dipping io°-20° N. 70° W. On the north
slope, east of the road, are numerous embossed ledges, probably of the
same character. The first rocks seen in Hill are not adjacent to these
andalusite beds, and they are Montalban ferruginous schists, dipping
south-east. Our observations on this eastern line indicate the existence
of a probable anticlinal, but information sufficient to establish the nature

588 STRATIGRAPHICAL GEOLOGY.

of the other folds in the range is wanting. There is one correspondence
between the Kearsarge and Rockingham schists : both contain prominent
feldspathic or granitic beds near their borders, perhaps their lower mem-
bers. The former have not yet shown extensive bands of quartz, but
mention should be made of the small lenticular veins of rose quartz,
common both on Kearsarge and Ragged mountains. Large portions of
the ledges are thoroughly packed with andalusite. The crystals are
smaller than on Monadnock, or the east side of Mt. Washington, but are
well defined in certain localities, — sufficiently so to render probable the
reference of all the elongated prisms to the mineral andalusite rather than
fibrolite. The Kearsarge area is more sandy than the Monadnock, or
especially the Mt. Washington, which carries a great deal of argillaceous
matter. All these areas enumerated are believed to be of the same age,
and are so colored on the general map. Possibly the Kearsarge area may
reach into Franklin. I have not been able to traverse the road over the
continuation of this ridge in the west part of that town.

8. Merrimack Group.

I have not attempted to separate from the Rockingham series a narrow
band of Merrimack schists in Nashua and Derry. A few facts in refer-
ence to them have been already stated. There remain to be noticed a
few areas of rock, easily referred either to the Merrimack or Rockingham
series, mostly of a ferruginous character, between Francestown and Can-
terbury, The range is of importance, because it carries the soapstone
beds occurring in these two towns. The distribution of this rock indi-
cates its presence in three separate areas, — Canterbury, Boscawen, and
between Henniker and Greenfield, Except for a broad alluvial covering,
these three areas would not appear isolated upon the map.

There is not a predominance of quartzite in these rocks. Ferruginous
and mica schists, with feldspathic beds, constitute the prevailing strata.
The first have lost their original appearance, by the decomposition of the
ferruginous mineral, and might perhaps be called pyritiferous quartzites,
before disintegration. The soapstone of Canterbury is supposed to lie
in this rock. It is about a mile and a half south of the station. There
seem to be two beds of the stone, one hundred feet apart, separated by
hard hornblcndic masses, and each about twenty-five feet wide. On the

GEOLOGY OF THE MERRIMACK DISTRICT. 589

east side is a broad, white feldspathic band, with the dip of 50° W. This
extends south-east to the cross-roads near A. Sargent's. This band must
be three fourths of a mile wide. At J. Neil's and G. Barney's, near the
south-west corner of Canterbury, is a mica schist, dipping 75° S. 15° W.
In the edge of Concord is a very ferruginous schist, dipping 70° N. 50'^
W. Nothing is known of the extreme north-east extension of this rock
in Canterbury. Its limits are marked on the map at random.

In Boscawen the ferruginous schists occur at the village, dipping east.
The most western outcrop is near a saw- and turning-mill, next W. B.
Burpee's, and it reaches northerly to Salisbury. Back from Fisherville,
among the houses, is a slaty, ferruginous rock, dipping 35° N. 30° W.
Several ledges occur for a mile. At L. Morrison's the quartzites are
interstratified with andalusite bands, dipping 70° N. 20° W. There is a
feldspathic ledge here, also. Taking a deserted road towards Horse hill,
we pass gneissic rocks just at a brook-crossing, the dip being north-west.
In Concord the dip is 78° N. 40° W. At Mast Yard ferruginous slate
dips 55° N, 65° W. It occupies most of the west edge of Concord, next
Hopkinton, and the whole of Hopkinton south of the Contoocook river.

There are some indications of soapstone at a school-house by Mrs. J.
Butterfield's, at four-corners in the west part of the town, dipping north-
west. Between D. Tucker's and R. P. Copp's, farther west, is a repeti-
tion of the white feldspathic rock seen in Canterbury, which dips to the
north-west. The rocks on the north side of the Contoocook are crossed
by Section IV, and include the soapstone at Davisville in the south-east
corner of Warner, The schists here dip S. 50° E., and they crop out
strongly on the east side of Warner river in Webster. The soapstone is
certainly twenty feet thick, and has been quarried slightly. About on
the south town Hne of Warner flinty schists dip 65°-70° N. 6t>° W. This
rock crops out at the shingle-mill, and at Annis's and Rand's, with fibro-
lite. On the hill south of Bear pond in Warner, hard quartzite schists
dip 75° S. 70° W. Similar ledges crop out on the hill to the west of J. B.
Colby's in the north-east corner of Henniker. Near J. Foster's, a mile
west of Gove's pond, the dip is 80° N. 73° W. South of the Contoocook
in Henniker are several exposures of mica schist thought to belong to
this formation. At the old railroad crossing, a mile north of the Weare
line, is a massive rock dipping 10° N. W. South of A. D, L. F. Connor's

590 STRATIGRAPHICAL GEOLOGY.

it is high to the west ; farther south it is east of north. The high hills
to the south are made of it. This range terminates against the Deering
Montalban series.

In Weare the principal range is embraced between two areas of Lake
gneiss. Near the north line of the town a large hill contains mica schist
dipping N. 60° E., perhaps making an anticlinal with those in Henniker,
just named. In the west part of Weare there are numerous outcrops of
ferruginous and mica schists dipping north-westerly, as two miles north
of Clinton Grove, and a mile west. Mt. Misery and Odiorne hill are
composed of this rock, and perhaps a part of Wallingford mountain. The
top of Mt. Misery dips north-west. Just over the soapstone fibrolite
layers may be seen. The soapstone lies on the south-east slope, and is
about sixty feet wide. It has been opened extensively by Hon. M. A.
Hodgdon. It is of the same character with that in Francestown, and
perhaps on the same line of outcrop. Both are characterized by massive-
ness, arising from the uniform dissemination of crystalline radiated bunches
of talc through the rock. Minute bits of pyrrhotite occur occasionally,
but they do not seem to injure the stone for use in the manufacture of
stoves. Two horses, or large masses of hard rock, occupy a considerable
portion of the breadth of the bed ; but they may disappear, as the rock is
quarried deeper into the hill. There is arsenopyrite here also, with
asbestus and crystals of feldspar. Portions of the wall rock are horn-
blendic. At the south base of the mountain is a westerly dip, and the
rocks on the slope are both ferruginous and fibrolitic. Ferruginous
ledges appear with westerly dips at W. H. Hutchins's saw- and grist-mill,
north of J. M. Waldo's, and at the school-house by the cross-roads at D.
White's, dipping 50° N. 65° W. Between this point and L. Locke's all
the ledges are ferruginous. This is a particular band extending into
Francestown from Mt. Misery, just north-west of the soapstone. Its
place would seem to be near the school-house just named, where a little
of the same rock has been found. The fact of three localities of this
rock along a line just bordering the ferruginous band should be remem-
bered in further explorations. At the town farm in Weare the ferrugi-
nous schists dip 50° N. W., and also in the east part of Deering, inter-
stratificd with hard schist. The formation extends to the Lake gneiss.
The Francestown soapstone is one of the most important beds of this

GEOLOGY OF THE MERRIMACK DISTRICT. 591

substance quarried in New England. It is known to be four hundred
feet long and forty feet wide, seems to be free from horses, and is all of
good quality. It dips N. W. 60°, and has been excavated to the depth of
one hundred feet. Mica schist is found on the south-east side. At
Francestown village ferruginous schists dip north-west, and also half a
mile north-west of the turn of a road to Deering. The whole of the
eastern part of the town is composed of the same material. Near the
south-east corner it is compact and twisted. At S. Duland's, near the
Greenfield line, the dip is 50° N. 85° W. Ferruginous quartzite crops out
at the south-east end of Haunted pond, with the strike N. 57° E., and
vertical strata. The same is true of the rocks at S. Langdell's, in the
west part of New Boston. Between this point and S. & J. P. Todd's, the
white feldspathic rock described in Canterbury and Hopkinton makes its
appearance. At times it resembles a conglomerate. With it are gray
quartzites, and soft, talcy strata resembling soapstone. The ferruginous
rocks of this series make a branch into New Boston from the main rano-e,
and are believed to extend as far as the lenticular drift hills on both sides
of J. Cochran's. South-west from Francestown the ferruginous band
occupies the space between the Rockingham schists of Lyndeborough
and Temple mountains, on the east end of the gneissic areas to the west,
perhaps extending into the north edge of Peterborough. The mica
schist at the south end of Cragin pond, Greenfield, dipping 85° S. 50° E.,
may belong here. On the north-east side of Pollard pond ferruginous
mica schist dips 70° N. 30° W. The short Henniker and Warner range
is obviously a repetition of the longer bands, while that is folded in Weare,
and probably also in the east part of Francestown, in connection with the
spur running into New Boston. The similarity of the rock to the Rock-
ingham series is quite obvious, especially if the feldspathic beds may be
the equivalent of those in Londonderry, etc. The presence of the soap-
stone may be a still better band of union. Boulders of soapstone occur
in Pelham, and a short distance over the Massachusetts line, in Dracut.
They are of large size. I have also seen specimens of the rock from
Island pond in Hampstead. These fragments must have been derived
from the Merrimack or Rockingham group, from some ledge north of the
localities of the boulders, perhaps the continuation of the Groton range.

CHAPTER VII.

GEOLOGY OF THE LAKE DISTRICT.

*J|lIHIS is the smallest of all our areas of description. It properly
Jf% embraces the hydrographic basin of Winnipiseogee lake, the flat
country to the north, and the rest of the territory as far as the state line
of Maine. There is a large tract in Maine represented upon the map,
chiefly of Montalban rocks ; and the extremely few facts concerning them
in our possession would properly be noted here. For convenience, I will
include the whole of the porphyritic gneiss of the Squam Lake region
and the Montalban and Moose Mountain granite areas lying partly in the
Coast district. I will leave out a very inconsiderable tract of mica schist
in Alton. Thus limited, we have only three stratified groups to sketch :
I. Porphyritic gneiss. 2. Lake gneiss. 3. Montalban. The eruptive
rocks are more plentiful and varied, consisting of i. Conway. 2. Albany.
3. Chocorua granites. 4. Porphyry. 5. Pequawket breccia. 6. Labra-
dorite diorite. 7. Sienite. 8. Granite, not allied to any of the foregoing.

I. PoupiiYKiTic Gneiss.

The principal area of this rock has the shape of a fish-hook. It comes
out of the White Mountain district into Sandwich and Ashland, makes
its principal curve in New Mampton and Meredith, and runs to the point
just south of Squam lake, while the barb takes a course east of south
through the east part of Meredith, and crops out occasionally along the
west shore of Lake Winnipiseogee. On the north-west side are two

GEOLOGY OF THE LAKE DISTRICT, 593

small areas, one of which, Mt. Prospect in Holderness, is the culminating
point ; and the other extends from the north corner of Sandwich into
Waterville, occupying the north flank of Sandwich Dome. A third
occurs at J. H. Calder's, in the southern edge of Thornton. There
is but a single outcrop, dipping 20° S. 50° E. The Montalban of
the Dome is probably an overlying mass in the porphyritic basin. The
range in the north-west part of Sandwich exhibits in a section a fan-
shaped structure. The dip of these rocks on the south-eastern slope of
Squam mountain, in the north-east part of Holderness, is north-west.
Taking the road over this range, the hard, ferruginous schists predomi-
nate, dipping north-west. Section VI crosses this formation, and also
shows the fan-shaped structure. South of Little Squam lake in Holder-
ness is almost a mountain ridge of this rock. We find a north-west dip
at J. Weeks's in the north part of New Hampton ; a mile south, towards
Shaw's hill, the dips are S. 25° W. and N. 50° W, On the ridge between
Shaw's and Beech hills the feldspar crystals do not lie in any uniform
plane. Schist intervenes before reaching the stream to the south; and
at J. H. Harper's the porphyritic rock dips easterly. By H. Harper's, on
the north flank of Harper hill, are dips of N. 50° W. and S. 30° W. West-
erly dips prevail along the west border of the formation towards New
Hampton centre. From this village, for two miles towards Meredith, is
the most beautiful display of porphyritic gneiss I have ever seen. The
crystals of feldspar are of large size and very beautiful. Other ledges
occur in New Hampton near the railroad, but I have not preserved any
record of their dips. The western border of the formation assumes a
south-east course beyond New Hampton centre, reaching Great bay in
the town of Sanbornton. The rocks on the hills overlooking the bay are
interesting, on account of the perfection with which the twin crystals of
feldspar are displayed, and also for bunches of a mineral like fibrolite dis-
seminated through the ledges. On the west side of Randlett's pond the
dip is 75° N. 60° W. Between Meredith centre and the south line of
the town is a rich profusion of porphyritic ledges. At the road crossing
the outlet of Pickerel pond the rock dips westerly. West of this pond is
a crystalline trap dyke, ten feet wide, exposed for one hundred feet, with
a north and south course. The feldspar crystals in the north part of
Laconia have the direction N. 70^ E., and these are supposed to indicate
VOL. II. 75

594 STKATIGKAnilCAL Gi:OLOGY.

the course of the strata. The rock crops out in several places as far as
to the cemetery close by the north end of Round bay. We sec it again
on the point and hill back of the Wicrs station. It is the only rock seen
between Wicrs and Meredith Village. On Wadleigh's hill arc two large
veins of quartz, — one, on the summit, a fo(;t wide, with a norLli and south
direction; the other of double width, nearer the lake, and showing decom-
posed ankcrite and dolomitic crystals. Both are vertical, and traceable
for half a mile. There are several exposures of this rock between Mere-
dith and Lake villages on the nearest road. The outcrops at the former
village dip north-west. At S. M. Lawrence's, west from the Centre, are
ledges of hornblende rock — an unusual occurrence in this formation. On
the east side of the north-west cove, ledges of porphyritic gneiss are
abundant all the way to Spindle point. Rollins hill, the highest land on
the Neck, is compo.sed of a hard schistose rock, peculiar to this forma-
tion, dipping 80'' N. 65° W. The middle ridge of the Neck shows por-
phyritic gneiss back of W. Mead's. This is the eastern limit of the rock.
Stonedam island would naturally belong to this group. This rock occurs
on the high land west of Little pond, and near B. G. Young's on the high
land to the north. On top of the hill west of the Center Harbor landing
this rock appears in not very great amount, perhaps three fourths of a
mile wide. There are two important localities in Center Harbor, — one
at the extreme south end of Squam lake, by an old saw-mill, the other on
Sunset hill. All the ledges here dip northerly.

The barb of the fish-hook is to be found in the country south of Mere-
dith Neck, I have not examined Pitchwood island, but Eagle island, a
mile off Wicrs landing, is composed of porphyritic gneiss. The same is
found at the south end of Governor's or Davis island, dipping S. 85° E.
The north end of Gilford is underlaid by the same material, and probably
the area of Smith's Neck. Adjacent to the northern end of the Belknap
range the porphyritic gneiss dips 75*^ N. 80° W. Welch and the other
islands opposite have not been explored.

About three miles from Alton ]5ay landing, on the west side of the
water, is a mass of porphyritic gneiss, intercalated with the other variety,
dipping west. The high land bordering the water may contain consid-
erable of this material. It also occurs on a cross-road at J. P. Gilman's,
with sicnite. An area known to be longer occurs between Avery hill and

GEOLOGY OF TIIK LAKE DLSIKICT. 595

Pine mountain. The line of junction l)ctwcen the j;neiss and sicnite is a
perpendicular seam running cast and west. The dip of the gneiss is east.
The gneiss occupies the lower ground, the sienite the hills adjacent.
There is a possible additional locality of this rock in New Durham.

The most remarkable feature of this range is its singular double curva-
ture. So far as our observations extend, it seems to be a real bending of
the strata, rather than an accidental uncovering of an older unconformable
formation by the abrasion of the superincumbent groups. The latter
have been involved in the bending and overturning, and it is a significant
fact that the Lake gneiss within the folds of the hook d(jcs not come up
again on the west side in Ashland. Were the fan-shaped stratification
along Section VI a synclinal, as a slight examination might suggest, then
the Lake gneiss should reappear in the Pemigewasset valley. That it
does not, confirms the truth of our theory that the porphyritic gneiss is
the oldest.

3. Lake Winniimsko(;i;e Gneiss.

This formation has been so well defined already that it is unnecessary
to speak of its particular character in the region where it was first recog-
nized. It has stratification not easily recognized, occupies low ground,
occurs in embossed ledge.s, .showing stria; wherever disintegration has not
been too rapid, and is traversed by numerous segregated veins. These
features are suggestive of Laurentian age. I have in the first chapter
called the formation "Atlantic," signifying a period intermediate between
the Laurentian and Iluronian. I shall not find fault with any who seek
to refer it to a still older period. The general course of the area occupied
by this gneiss is north-west and south-east, and it corresponds very
nearly with the direction of Lake Winnipiseogee. There is a branch on
the west, leading southerly to Meredith, and a widening of the territory
occupied at the Maine boundary line. The extreme length of the area is
thirty miles; average, twenty-two and one half; average width, eleven :
total dimensions in square miles, about two hundred and sixty. The fol-
lowing are our principal observations respecting the position of strata:

Sandwich. Between North and Centre villages, many

At A. Y. Irving's, beyond North Sand- ledges on both roads, usually vertical,

wich. with strike N. 60° E.

596

STRATIGRAPHICAL GEOLOGY.

At M. Bean's, and all through west part of
town, dip north-west, nearly vertical.

Near Hart's saw-mill, north-west part of
town, 72° N. 70° W.

One mile south-east of last, dip south-east.

On Israel's mountain, dip northerly.

Near J. D. Cook's, with quartz, strike
N. 30° E.

At S. Dinsmore's, next sienite, dip south-
east.

Tannvorth.

At South Tamworth, 45° N.

At N. Locke's, near west line, 55° W.
Moidtonborough .

East side of Round pond, M. Hutchins's,
80° S. E.

At T. S. Adams's, south of sienite, 60° S.
60° E.

South side of Long pond, 60° S. 60° E.

East base of Sunset hill, 80° E.

Half a mile east of landing. Center Har-
bor, J. Graves's, 85° E.

Near stream at Centre village, dip westerly.

At A. B. Hoyt's, 80° E.

Between P. Brown's and H. Thompson's,
55° N. W.

At H. Smith's mill, 45° N. 85° W.
Center Harbor.

Near M. "Wade's, promontory of Squam
lake, dip south-east.

East of J. G. Thompson's, dip westerly.

West of Bear pond, 80° S. 50° E.

East side of Long pond, dip north-west.

Abundant between Long pond and Mere-
dith Village, dip north-west.

At J. W. Paine's, south line of town, north-
west.

Holderness.

East base of Shepard's hill, anticlinal line,

north-east and south-west,
Meredith.
Back of H. Bedee's, north of village, 70°

N. 80° W.

Near W. Jenness's, near town line, 70°
north-west.

Near Advent church on Neck, 65° N. 50°
W.

At chair shop, near J. Ouimby's, N. 70°
W.

At Meredith centre, dip west.

West side of Lake Wukawan, dip westerly.
Tiifioiiboroiigh .

At Tuftonborough corner, dip north-west.

Near S. Mclntyre's, 70° N. 85° W.

At Tuftonborough Neck village, dip W.

At "Canaan," vertical, strike north-east
and south-west.
Islands in Lake lVin?tipiseogee,

On Sandy island, east end, 85° E.

On Long island, south-east point, N. 85°
W.

On Jolly island, east and north sides, 60°
S. 80° E.

On Mark island, south-east dip.

On Governor's island, north end, 50° E.
Wolfeboro7(gh.

Near N. Brewster's, dip north-westerly.

Same towards Smith's pond.

Near G. W. Nute's, dip east.

At Porcupine ledge, near North Wake-
field, 70° N. 80° W.

Quartz at the same, 70° N. 60° W.
Alton.

At West Alton, dip west.

Near H. Hunt's, east of bay, 80° E.
Brookfield.

North corner of town, dip north-west.
Wakefield.

At S. Cook's, dip south-east.

Quartz at L. C. Perry's, dip 80° N. 50° W.

At N. H. Cook's (Peavey place), 15° W.
(limestone).

Quartz near foregoing, dip N. 60° W.

Near D. W. C. Wentworth's, dip north-
easterly.

GEOLOGY OF THE LAKE DISTRICT. 59/

Ossipee. Quartz, at O. Sanders's, strike N. 50° E.

At Samuel S. Fogg's, small southerly 90°.

clip. On Pocket hill, clip north-westerly.

Some of these dips are embodied in a section from Hart's saw-mill in
north-west Sandwich to the west base of Ossipee mountain (Fig. 104).
The strata generally run north or north-east, so that they do not con-
form to the direction of the area as it is laid down topographically. The
inference from this fact would be that it may continue indefinitely, both
to the north-cast and south-west, underneath the adjacent Montalban.
These observations show the presence of several axes. The Meredith
branch gives mostly north-westerly dipping monoclinal strata, as would be
expected from the inverted position between walls of porphyritic gneiss.
The anticlinal at the east base of Shepard's hill cannot be of much con-
sequence, unless it be proved more extensive. The Sandwich dips are
so nearly vertical that folds may be numerous. There seems to be a syn-
clinal west of the quartz; one for the sienite of Red hill; another along
the west base of Ossipee mountain ; and one strongly marked at Moul-
tonborough centre. Anticlinals appear west of Long island and through
Wolfeborough. The long fiord of Alton bay is situated upon an anti-
clinal. Between Tuftonborough corner and Canaan it seems like a syn-
clinal. Fig. 105 will show these axes in a section crossing the whole area
at right angles from Sandwich to Wakefield.

I will mention a few points of interest in these several towns. At C.
F. Hawkins's, Center Harbor, this rock carries a five-foot vein of porphy-
ritic granite. At C. Chase's, on the line between Meredith and New
Hampton, small crystals of feldspar are scattered through the rock. At
South Tamworth the rock is like the Bethlehem gneiss, including a hard
siliceous layer. The strata are highly siliceous and ferruginous in the
extreme west part of Sandwich, and this formation extends only a little
way into Holderness. At the east end of Sandy island is a vein of very
coarse granite, with large crystals of feldspar. At the south-west comer
of Long island and on Mark island are numerous beryls. Trap and
other dykes occur at the following places : Irregular trap dykes, with very
pretty, small granite veins, at S. Mclntyre's, Tuftonborough ; small trap
band on Jolly island ; one four feet wide at Canaan ; dyke of hornblende
and feldspar fourteen feet wide, seen for twenty rods, on the east side of

598 STRATIGRAPHICAL GEOLOGY.

Lond pond, in Meredith, with course N. 30° E.; trap, west of S. and S.
Fogg's, Ossipee ; near Wolfeborough village and other places.

The quartz bands of the Manchester gneiss occur here, also, though
they have not been traced out so carefully. As they extend but a
short distance, they cannot be expected to be so well developed. It is
possible that two of the ranges seen in the Lake district are the natural
continuation of those in Hillsborough county after their emergence from
the mica schist blanket, and beyond the eruptive mass of Moose moun-
tain. An examination of the map will show that the Hooksett and Man-
chester bands might correspond to these in Strafford brought up with
the gneissic island, then, submerged again, turning to run more northerly,
and reappearing in Wakefield and Effingham. In Wakefield the eastern
range is one hundred feet wide at L. C. Perry's, midway between
Wakefield and East Wakefield stations. There are also signs of the
quartz at B. Drew's. At the Peavey place (N. H. Cook's) limestone
just like that in Amherst, with similar associated minerals, — epidote
and molybdenite, — overlies the quartz, dipping to the north-west, ex-
posed in a ledge twelve feet wide. Inasmuch as the related rocks here
agree in mineral contents and position, we have reason for believing this
is the Manchester band of quartz prolonged into the Lake district. It
may be the same with that on the town line close by Province pond. To
the south there is a similar band, to be mentioned under Montalban, on
the north side of Lovewell's pond, which occupies very nearly the place
of this range, but is a superior formation. The Hooksett range appears
on Porcupine ledge, near North Wakefield, in the east corner of Wolfe-
borough. The quartz is more than a hundred feet wide, lying somewhat
to the rear of the precipice. It may be traced for several hundred feet
in length, and dips north-westerly; so that both ranges are inclined in
the same direction. It is said there is a ledge of quartz at C. Hodgdon's
in Ossipee. I have not been there, but it is exactly on the line from the
Porcupine ledge to Pocket hill in the east part of the town. At O. San-
ders's it runs up hill, being vertical, in the direction N. 50° E., and it is
fifty or sixty feet wide. It has been explored by miners in search of the
precious metals. There are indications of the continuance of this range
at B. H. Emerson's and J. Leavitt's, 2d, in Effingham. The boulders are
almost large enough to be called ledges. These two bands have been

GEOLOGY OF THE LAKE DISTRICT. 599

converging. Those in Wakefield and Wolfeborough are three, and these
near Province pond but one mile apart. Those who come after us may-
find the extension of these bands in Maine, Effingham being the border
town of our state.

The limestone of Wakefield deserves a further notice. It is a siliceous
rock of peculiar appearance, from the presence of a green mineral, per-
haps pyroxene. Its stratigraphical place being known, great interest will
be attached to other localities where the associations are somewhat dif-
ferent. In Brookfield, near the "corner," are large quadrangular blocks
of this rock, looking as if they had not travelled a hundred feet from
their source. There is a siliceous rock resembling this in color, dipping
60° W., at A. Berry's, west of Cook's pond. A related ledge at J. Per-
kins's, a mile east of the corner, dips 40° N.; a mile south-west from the
village of West Newfield, Me., small boulders of this rock are very nu-
merous. There is a limestone bed at the Davis mine, on the east side of
Balch pond in this town, which is of this material. In Acton it is quite
characteristic, dipping 5° S. W. a mile west of the south end of Manson
pond, and is associated with gneiss. Near school-house No. 10 of Milton
the blocks are sufficiently numerous to inspire a belief in the existence
of a ledge near by. I think the limestone beds described by Jackson in
York and Oxford counties, Me., may be of this same variety; and further
study may eliminate interesting facts concerning their stratigraphical dis-
tribution.

There is a peculiar granitic rock occupying a portion of the east rim
of the Winnipiseogee basin. Batson and Trask hills, and Whiteface
and Cotton mountains, along the east line of Wolfeborough, are com-
posed of it ; and on the continuation of the ridge near J. Jenness's in the
same town, at the church on the high land east of Cotton Valley station,
and on the hill north of Cook's pond in Brookfield, similar rocks occur.
It curves from a south-east course, and runs southerly towards Cropple
Crown. I have esteemed the material as gneiss, and have not distin-
guished it upon the map separately from the Lake group. I have not
been able to find marks of stratification in it, though diligent search has
not been made for them. The occurrence of this rock along a line of
hills suggests a possible connection with the Mt. Bet series of granites
in New Durham. The east sides of Whiteface and Cotton mountains are
precipitous.

600 STRATIGRAPHICAL GEOLOGY.

3. MONTALBAN SeRIES.

The Montalban rocks of the Lake district may be grouped in two
areas : first, those occupying the north-east portion of the territory ; sec-
ond, those encircHng the Moose mountain eruptive rocks, lying partly in
the Coast region, but described here for convenience. We may group
the dips as follows :

Samhvicli. Effingham.

On Guinea hill, 52° N. 53° W. Near A. W. Drake's, 70° S. 70° E.

At Weed's mills, 50° N. W. At W. Rumney's mill, 80° N. 85° W.

Near L. C. Clark's, east line, 55° S. \V. At south-west corner, N. 70° W.

TamivortJi . Tuftonborotigh .

At W. Cushing's, N. 30° W. At J. Bean's, east corner, 50° N. W.

On Stevenson's hill, near West line, north- At T. Durgin's, near corner, west.

west. Freedom.

At Tamworth centre, westerly, small. At village, 75° W.

At South Tamworth, 30° southerl}^ East part, westerly.

One mile east of South Tamworth, 50° N. At E. Wood's, West Freedom, 50° W.

Madison. Ossipee.

Near John L. Frosfs, 60° N. W. At Water village, 60° N. W., contorted.

At Lead mine, 60° N. 75° W. One mile south-west of court-house, 30° N.
At L. Long's, 60° W. to N. W. 85° W.

Farther cast, S. 65° W.

It is surprising to find the Montalban rocks over so large an area as is
indicated by these figures, possessing monoclinal dips. In rocks at the
north base of the Ossipee mountains are evidences of anticlinal structure,
but in a gneiss greatly resembling the Bethlehem group. In Effingham,
on the south side of a large intrusive mass, are synclinal dispositions, but
everywhere else the inclination is uniform. To understand this arrange-
ment we have to resort to the supposition of extensive inversion, as has
been already explained (p. 253). The great central anticlinal of Frye-
burg, Me., does not, however, make its appearance through Eaton and
Madison, as would be the case if the rock in the Lake district con-
formed to those farther to the north-east. It may pass a little more to
the east, and manifest itself in the Green Mountain granite of Effingham.

A few points require special mention. At Weed's mills. Sandwich, the
gneiss is a little like the segregated variety, with interstratificd ferrugi-

GEOLOGY OF THE LAKE DISTRICT. 60I

nous bands. Across the north part of this town, and the north of Tam-
worth, no ledges appear, everythhig being covered by drift. Since the
preparation of Plate XII I have thought best to connect this North
Sandwich area with the outcrops on the Chocorua range (p. 133), elimi-
nating the intermediate granite, thus located in consequence of a mis-
understanding. This gives us an area twelve miles long and from two to
three wide, possibly isolated from connection with the principal part of
the formation. We can easily understand that this may consist of a folded
synclinal, separated from the Tamworth exposure by an inverted anti-
clinal. At L. C. Clark's, andalusite is present in the ledge, and there are
two small trap dykes. On Stevenson's hill, in Tamworth, the rocks are
indefinite, — granitic, gneissic, and ferruginous. At T. Perkins's, north of
the Iron Works, is a coarse granite vein. Between the two Tamworth
villages are gneissic outcrops, whose dips are not recorded. At W.
Cushing's, the ledges are mostly of the granitic varieties. The east part
of Tamworth and the west part of Madison abound in high, isolated hills,
mostly of a granitic variety of the Montalban series, where stratified
planes are scarcely recognizable, yet the Montalban character of the
material is evident. Chatman hill contains much coarse, indigenous
granite. At J. Lyman's, on the south-west side of Hedgehog hill, Madi-
son, is a granitic gneiss. Pine hill is probably composed of the same
material. There is a granitic rock at N. Snell's, in Tamworth, nearly two
miles west. The same, with ferruginous rock and trap, is repeated at
the school-house on the north-east corner of the town. The hill south-
west from Whitton pond, in Madison, is composed of Concord granite,
with jointed seams dipping 60° N. W. The north-west side of this hill is
precipitous. The hill a mile and a half east of this is thought to be com-
posed of similar material.

The east part of Madison is separated by a broad valley from the west,
just considered ; and the stratified schists take the place of the Concord
granites. Very few observations have been made in this region. At L,
Long's and farther to the east the strata are variable. Some of the finer-
grained mica schists are traversed by segregated veins, and weather like
the siliceous limestones of eastern Vermont. The usual dip through the
town of Eaton is 5o°-6o° W. The rock at the old lead mine in Madison,
formerly Eaton, is largely composed of silica. On the east side of White's
VOL. II. ^6

602 STRATIGRAPHICAL GEOLOGY.

pond, in Tamworth, Dr. Jackson visited an excavation for lead mining in
a "solid vein of reticulated and compact jaspery quartz rock." This sug-
gests the possible existence of one of the Hillsborough county bands of
quartz. Two miles north of "Atkinson's tavern" Jackson found an inter-
esting assemblage of igneous rocks. They were dykes of a "singular por-
phyry, having a greenish, compact feldspar base. The porphyry dykes
cut through a hill of granite composed of a pure white feldspar, quartz,
and bright transparent mica. Porphyritic granite also abounds in the
vicinity. These dykes, from ten to sixteen and a half feet wide, traverse
this rock, and run in a N. 70° E. direction. One of the dykes contains
carbonate of lime in sufficient quantity to produce rapid effervescence
with acids. It contains, also, crystals of hornblende, epidote, and feld-
spar." Iron and copper pyrites in small amount occur in one of these
dykes. At Freedom village I found large boulders of a peculiar sienite,
which has not yet been seen in place. In the east part of the town are
occasional eruptive masses of a porphyritic granite like that composing
the bulk of Green mountain in Effingham. Near the Maine line the dip
is 15° S. 80° E. At the north end of Ossipee pond the dip is 45° W.

TJie Southern Area. This seems to be a belt two or three miles wide
surrounding the eruptive granites of Moose, Cropple Crown, and other
mountains on the borders of Carroll and Strafford counties. In the east
part of Wakefield there is an anticlinal, with the ridge near T. Chapman's,
where the rock is a micaceous gneiss, with coarse granitic beds, and the
dip is 15° S. E. At the outlet of Newichwannock pond the dip is 25° in
the same direction. The rock is cut by trap dykes carrying calcite, dip-
ping north-west, also by large granite veins. The opposite dip appears
on Brackett's brook, a tributary of Lovewell's pond. Here is a quartz
band, also, adjacent to gneiss, inclined 75° N. 70° W.; and another half a
mile north. On top of the hill south, near J. Copp's and the town line,
ferruginous and mica schists, dipping 25°-30° S., are cut at right angles
by granite veins several rods wide. Similar rocks at N. Kimball's, a mile
east of the Branch river, have a strike east of north. Between the Junc-
tion and "corner" the schists dip 50° N. 10° E., with granitic layers. At
Union Village, typical Montalban schists and granite dip 12° N. 40° W.
Nearly three miles to the north, by E. P. Oilman's, hard granitic beds
dip 80° W.

GEOLOGY OF THE LAKE DISTRICT. 603

Tumble-Down-Dick and Mt. Delight, in the west part of Brookficld,
show the Montalban schists well, dipping 50° N. 85° W., and 85° W. near
R. H. Piper's. The range crops out to the north-east on the Wolfebor-
ough line, dipping 45° N. 80° W.; also at D. F. Stoddard's the mica
schists dip 14° N. 85° W. At J. Goodhue's, Brookfield, is an irregular
granitoid rock, with trap. On the north side of Cotton Valley station
are ferruginous schists, inclined 50° W., about one fourth of a mile wide.
At the northern base of the granite mountains, in Brookfield, ledges are
scarce ; but there are mica schists at G. W. Chamberlain's. These facts
show the development of the Montalban rocks between the granite range
and the usual Lake gneisses near the Wolfeborough line, and a decided
anticlinal in the east part of Wakefield. The variations in the angle of
the dips in Wakefield suggest the presence of a synclinal.

Along the line of Section V there seems to be a synclinal in Middle-
ton, — there being a dip of N. 20° W. near J. B. Stevens's and at Mrs.
Gibbs's. The easterly dip appears at a "mine" a mile west of the road.
The veins there are of coarse granite, containing the minerals mispickel,
tourmaline, mica, and feldspar crystals. An anticlinal follows, as there is
a south-west dip of mica schist and granite in the east part of New Dur-
ham, where the road crosses the Cocheco river. The change to a north-
erly dip is seen at a mill at New Durham corner and at G. D. Savage's, a
little north, 80° N. 5° E. On the north side of March's pond the mica
schist is full of granite in its crevices. The dip changes from other east-
erly observations to N. 30° W., and back to N. 10° E., before coming to
Merrymeeting lake. After passing the granite, dips somewhat northerly
prevail through Alton to the lake. The rock on this route is therefore
full of subordinate undulations. Towards Gilman's pond in Alton the dip
is 45° N. E. There are sienitic beds a short distance west of Alton bay.

Eruptive Rocks.

These are finely displayed in the Lake district. Perhaps the southward
extension of the Chocorua group into Tamworth has been already suffi-
ciently mentioned in Chapter III. There is also a large ledge of Albany
granite in the south-east corner of Thornton. Besides that, there are four
important eruptive areas: (i) of the Ossipee mountains; (2) Moose moun-
tain, etc. ; (3) Red hill and Gunstock ; (4) Green mountain. No two of

604 STRATIGRAPIIICAL GEOLOGY,

these areas resemble each otlicr at all, and each one constitutes a moun-
tain mass.

Ossipec group. We find this is an elliptical mass, nearly round, a little
more than half composed of porphyry, with a narrow belt of Albany gran-
ite on the west side, a considerable tract of Conway granite in the east,
and the Pequawket breccia on the north-east. The porphyry is better
developed here than anywhere else in the state. It is partly brecciated
and partly stratified, like a clay slate without very many cleavage planes.
An excellent place to see this rock is near the hamlet east of South Tam-
worth, half a mile up the mountain's side, where some have fancied there
might be cord. The rock is a fine, compact fibrolite, with occasional
black scams resembling bony coal, dipping 15° S. 20° W., or into the
mountain. Drift conceals most of the ledges at the north base of the
mountain, but the slaty band crops out a mile west of the "coal"-opcning,
at the end of a spur. On following up the valley south from the village
of South Tamworth we find slates, felsites, and breccias at Thompson's
shingle-mill, mostly dipping west. Epidotic seams and bunches are plen-
tiful. Above N. Johnson's, compact, dark felsites have vertical seams,
with a north-east strike. The mountain south has not been visited. At
Ossipee falls, on the south side of the mountain, is a fine display of these
black and spotted porphyries. The joints at the top of the falls dip south-
east, in a reddish rock. The lowest slate seen is black with greenish
spots, inclined 25° N. W. The ridge south of Canaan is a coarse gray
fclsite. North of Dan Hole pond a steep hill is comjiosed of a black,
spotted felsite, with joints dipping 60° N. 25° W. We also find felsite a
mile south of l^ear Camp river, just in the edge of Ossipee, in the valley
north of Mt. Whittier. The peak east of Mt. Whittier shows brecciated
porphyry, while the principal mass is a spotted granite containing slaty
fragments, thus resembling the Pequawket rock. Jointed seams run
N. 40° W., dipping N. 50° E. The smaller eminence just against West
Ossipee station is composed of breccia, some pieces of slate being two
feet long. Some ledges consist of a jumble of masses of the dark por-
phyry, almost too large to be styled a breccia. Above the "coal mine" is
a breccia, where the pieces are of small size, and the cementing material,
almost like trap, constitutes the principal portion of the rock. It com-
mences perhaps one hundred and fifty feet above the mine, and is believed

GEOLOGY or THE LAKE DISTRICT. 605

to extend to the top of the mountain. It is also seen farther west, on a
path used for cHmbing the mountain.

A strip of Albany granite has been noted upon the west side of the
area. From the top of the western spur, next South Tamworth, Prof.
Vose brought specimens of this granite. On climbing the mountain from
N. B. Hoyt's, on the line between Moultonborough and Sandwich, we find
this rock in its relations to others. First is the Lake gneiss, dipping 80°
E. ; then the porphyritic or spotted granite, about one hundred feet thick.
This is covered by a black felsitc, perhaps two hundred feet thick, and
that in turn is capped by a breccia. The Albany rock is also found
farther south, near the Ossipee falls. On the east side we find it north
of J. Hobbs's, nearly a mile west of Ossipee lake; and on the road up
Lovell's river into the very heart of the mountains, the rock is rather
intermediate between the Conway and Albany varieties. There may be
some of this rock on the north side of Mt. Whittier.

The Conway granite is also conspicuously present. From the house
of S. C. Abbott, a mile south of Moultonville, to the end of the road
under the highest Ossipee mountain, this variety predominates in all the
ledges. It is well seen on the ridge north of Moultonville. I under-
stand that this variety underlies the Albany, as in the White Mountains.
For this reason, and also because large blocks of the latter are common
about the lower end of Dan Hole pond and other places on the south-
east side of this area, I anticipate the discovery of the Albany rock in
place in Ossipee. Near J. Hobbs's are large boulders of a very interest-
ing labradorite porphyry. Nowhere else has anything been found that
shows the labradorite crystals so finely. It is probably in place on Mt.
Whittier. This area affords an excellent opportunity for the study of
these eruptive rocks, since it is comparatively small, easily accessible, and
what I have done can hardly be dignified with so full a title as a recon-
110 is sane e.

The Moose Mountain Area. This lies between the counties of Carroll,
Strafford, and Belknap, occupying, in order from the east, Parker, Bald,
and Moose mountains, Mt. Major, Cropple Crown, Mt. Molly, Devil's
Den mountain, Mt. Bet, Birch hill, and Mt. Eleanor. Moose mountain is
largely a felsite, passing into sienite. It is everywhere fine-grained, and
reminds one slightly of the Albany granite. The very summit is com-

6o6 STRATIGRAPHICAL GEOLOGY.

posed of a fine-grained granite. The ascent was made from the north
side. Near the end of the road, at the south base of Parker mountain
in Middleton, the same rock occurs. Next, on a trip from Wolfeborough
to Middleton, I found a fine-grained granite just to the south of the Lake
gneiss, near Rust pond, containing large spots of hornblende. A granite,
quarried somewhere in the southern part of Wolfeborough, resembles the
Concord very much superficially, but it splits and breaks more like the
Moose Mountain rock. Through the north part of New Durham a red
granite predominates. At the south end of Cropple Crown it is some-
what like the finer variety of Conway granite found about Mt. Nancy.
I think it is rather coarser on the east side, and this mountain may be
regarded as a granite. Very pretty banded traps occur in this granite.
There is one much coarser from a large hill north of Mt. Bet. From Mt.
Bet and the region east comes a similar red, crumbling granite, not un-
like that comprising the Profile in Franconia. These hills are sugar-loaf
shaped, crumbling down in the usual type of granitic decomposition.
Birch hill is sienitic, as indicated by loose blocks at its base; and Mt.
Eleanor, for a like reason, may be said to be composed of a fine-grained,
reddish, normal granite. It has about the grain of the Concord granite.
This whole eruptive mass is therefore quite unique, and well worthy of
further study. It is over eight miles in length. Merrymeeting lake is
very prettily situated near its southern extremity. The granite seems to
prevail at the western, and the hard feldspathic and hornblende varieties
at the east.

Giinstock a7id Red Hill. Two areas are alike in composition, — the
Red hill in Moultonborough, and the Belknap mountains. These are all
true sienites. The first is only three miles long. It is composed of two
summits, the most northern being the highest, and is much visited for
views, as it rises conically from quite a plain. The rock is a genuine
sienite, abounding in hornblende. Some ledges show the hornblende as
conspicuously as the coarse granite veins of Cheshire county carry their
tourmalines. Two kinds of feldspar prevail. All these eruptive rocks
will be very carefully described by Mr. Hawcs, in the mineralogical part
of this report ; and I will content myself with mentioning their general
occurrence and relations to the stratified rocks adjacent. Vertical joints,
with a north-eastern strike, cut through Red hill. The junction of the

GEOLOGY OF THE LAKE DISTRICT. 60/

sienitc with the gneiss may be well seen at the north end of the mass.
To the south of S. Dinsmore's in Sandwich, the gneiss dips 75° S. E.; and
the sienite rests upon it at the same angle. Joints dipping 5° N. cut
both rocks. Dykes of crystalline compact feldspar, three feet wide, cut
the gneiss at a considerable distance from the sienitic mass. Back of S.
Smith's, in the north-western part of Moultonborough, the joints in the
sienite run north and south, and stand vertical. At M. Hutchins's, on
the east side of Round pond, the two rocks seem to meet on the strati-
fied plane of 80° S. 85° E. At the south end of the hill the junction of
the two rocks is concealed by drift ; and the dip of the gneiss is uncer-
tain. At Moultonborough centre the gneiss is hornblendic, and it is
believed to dip westerly. Many of the ledges at the west base of Ossi-
pee dip west also. That would indicate that the Red Hill sienite came
up through a fault along a synclinal line. I have a suspicion that the
conical mountain just in the edge of Holderness, on the north shore of
Squam lake, will prove to be composed of sienite.

The Belknap Area. This lies in Gilford, Gilmanton, and Alton. It is
eleven miles long, and six miles in its greatest width, the general direc-
tion being parallel to the lake. The most northern exposure is opposite
Thompson's island in Gilford. It comes in contact with the porphyritic
gneiss, and it is more fine-grained than usual, full of dark hornblendic
spots, and brecciated. On the beginning of the mountain range, a mile
and a half south-west and back of J. Smith's, the rock is coarser. The
northern of the two most conspicuous peaks, directly east from the house
of N. Weeks, shows a rock of the texture of the Ouincy, Mass., rock.
Joints on the summits dip 75° N. 20° W., and also south of east. There
is trap dyke there, also, ten feet wide, with the course N. 65° W. Small,
reddish feldspathic veins are common. Part way up on the west side is
a vein of magnetic pyrites occupying one of the vertical fissures. Green
augite occurs on the mountain at some forgotten locality. The gneiss
dips 50° S. at the western base of the mountain, with joints, 85° S. E.,
which may possibly be taken for strata. As the gneiss in West Alton
dips westerly, it is likely the Belknap sienite has been exuded through
a synclinal fault just like that of Red hill.

The road from Gilford across the mountain to West Alton shows a
fine-grained, brecciated variety of the rock at J. J. Morrill's, where the

6o8 STRATIGRAPHICAL GEOLOGY.

west edge is touched. At M. M. Potter's it has the average coarse text-
ure. At M. Leavitt's, at the crossing of the road by the brook emptying
into the lake, is a very coarse and singular breccia, requiring further
examination. The coarser sienites occur as nodules in a rock resembling
trap, and the jointed planes dip westerly. A chmb to the pond on the
ridge south of Gunstock mountain shows the fine-grained variety predom-
inating on the way up, and also on the mountain to the east. Between
the water-shed in the road to West Alton and M. Leavitt's are several
of the brecciated outcrops. A climb of the south end of the mountain
shows us ferruginous mica schists and indigenous granite, and next the
sienite indurated schists dipping 80° N. 35° W. towards the south-west
spur of the former rock. The rock of the mountain is like that on the
northern peak, just described, and with similar accessories. The rock
has a reddish cast. Joints cut each other vertically, running north-west
and north-east. The summit rock is somewhat porphyritic, from the
presence of feldspar crystals. The sienite was not reached till we passed
up Mt. Straightback in Alton, at some distance beyond the end of the
carriage-road. In a large ledge one can see the sienite and porphyritic
gneiss joining each other, Avery hill is of sienite. Quite a large piece
is taken out of the sienite area here by the presence of porphyritic gneiss
and mica schist. The junction of the first with the sienite is well shown
between Avery hill and Pine mountain. The line of junction is vertical,
running east and west. The latter summit is probably of sienite, but has
not been visited. The two Rocky mountains are composed of the ordi-
nary variety of sienite. With them the rock terminates, and the country
becomes comparatively flat. The Rocky and Pine mountains, with Avery
hill, constitute a semicircular ridge like the half of an amphitheatre. The
best part of this sienitic area is away from the travelled roads, in the for-
est country, so that the facilities for its understanding are not good.
Diamond island, in Winnipiseogee lake, is made up of a fine-grained
sienite ; and it is presumed Rattlesnake island is composed of the same
material. Scarcely any of the islands at the south end of the lake have
been examined.

The Red Hill and Belknap sienites obviously belong to the same age,
as they are so much alike. They are both very free from admixture with
granites. The Tripyramid and Jackson sienites are to be allied with

GEOLOGY OF THE LAKE DISTRICT. 609

them rather than the Exeter or Quincy, and they are unUke the Chocorua
series. Opinions as to the comparative antiquity of these several eruptive
rocks cannot yet be suggested with any probabihty. They occur in the
midst of Lake and Montalban gneisses, while the granites have disrupted
andalusite slates.

Green Mountain Area. This is a little over four miles long and two
wide in the north part of Effingham. The prevailing rock is a porphy-
ritic granite, the feldspar crystals usually not exceeding half an inch in
length. I have seen this variety of rock for three miles along the south-
ern part of the area. Judging from this circumstance, and from the abun-
dance of large blocks dispersed by drift in the neighboring towns, I have
concluded the whole mountain might be composed of the same material.
I have found the Mt. Bet granite on the north side, at the ice cave. What
the material is upon the very summit can be ascertained only by actual
visitation. There are no schists cropping out adjacent to the granite on
the northern half of the area. A ferruginous mica schist at A. W. Drake's,
upon the south side, dips 70° S. 70° E. This makes an anticlinal axis
with the nearest ledges to the west, in Ossipee.

RocKS IN Maine.

The geology of quite a wide tract in Maine is presented upon our
sheets, opposite the three northern topographical districts. No geologist
has ever traversed the north-east portion of the northern sheet. It is
from the most meagre data that the delineation represented is based.
On the Magalloway river, specimens have been obtained of both the
Lyman and Lisbon groups of the Huronian. Mt. Eziscoos and the neigh-
borhood are genuine granites. There is believed to be a considerable
area of the Lake gneiss in Andover and westward. To the south the
great bulk of the formations consists of the Montalban series in its vari-
ous forms. There is a greater development of this group in Maine than
in New Hampshire.

One of the most interesting areas of igneous materials in Maine is the
trachytic rock of Mt. Pleasant, in the towns of Bridgeton and Denmark,
This elevation is recognized readily from the mountain summits of New
Hampshire, as it is a long mass rising up from an apparent plain. The
mass of the mountain is a sienite like that of Tripyramid, with tri-

VOL. II. T^

6lO STRATIGRAPHICAL GEOLOGY.

clinic feldspar. From the south end there extend large dykes crossing
Beaver pond, which are entirely composed of trachyte. This same rock
has been discovered by Mr. Hawes in Albany, since the printing of Chap-
ter III. It is a very interesting discovery, showing that what has usually
been regarded as a volcanic rock of tertiary age has also been erupted
in a much older period, and especially in the very ancient region of the
White Mountains. The rock will be fully described in Volume III.

I understand, from Mr. Huntington's statements, that the Montalban
rocks prevail through Parsonsfield, Cornish, and Limington with a south-
east dip. In Newfield, I found the same rocks abundant all through the
western part of the town. The granitic beds are the ones most usually
showing themselves. At the Davis mine, close by Balch pond, the dip
is high to the south-east, and probably elsewhere throughout the town.
Dr. Jackson describes sienite from "Thyng's mountain," without naming
the town where it belongs. None of the maps give any such name. He
speaks of it as the highest summit in the neighborhood ; and I have used
my judgment in locating it in the northern part of Shapleigh, near some
houses marked as owned by men having the same designation. I have
extended the area of Lake gneiss into Parsonsfield, because the peculiar
minerals of the Amherst and Wakefield limestone occur there in two or
three localities. When the exact place of this older gneiss is ascertained
beyond Parsonsfield, we may have the data afforded for tracing out the
master anticlinal of this region.

I have marked with more care the rocks from Acton across to Bidde-
ford. At first are the Rockingham schists, with north-west dip. There
is a small anticlinal by school-house No. 6, and north-west dips beyond.
Passing through South Acton village is a band of the Kearsarge andalu-
site rock, more conspicuous both to the north and south. Half a mile to
the east it dips io° W. The south-east part of the town is believed to
belong to the Lake gneiss. Very ferruginous rocks appear in Shapleigh,
about Emery's mills and at Spring Vale, in which an anticlinal structure
may be perceived. After this, we find compact feldspar and sienite in
Sanford and Alfred, All through Lyman is an ordinary granite, suc-
ceeded at Goodwin's mills by the Merrimack group. In Biddeford is a
very beautiful variety of the Conway granite, eruptive, and extensively
used for building purposes.

CHAPTER VIII,

GEOLOGY OF THE COAST DISTRICT.

KPhE Coast district embraces the south-east corner of the state, prin-
JC cipally Strafford and Rockingham, and a little of Belknap counties.
It lies altogether east of the Merrimack hydrographic basin, and includes
most of the Salmon Falls drainage area, save a little treated of in the
preceding chapter for convenience. It is the least elevated part of the
state. On a natural scale, where the horizontal and vertical are the
same, and the size that of our general map, the highest point in Rock-
ingham county would be elevated one sixteenth, and the most conspicu-
ous hill in the whole district, in Gilmanton, would rise only one eighth
of an inch above the base level. The general average would not exceed
one twenty-fifth of an inch. The great erosions that have brought the
region to this lowly condition have removed the crests of the folds to an
unusual extent; and the ice has been instrumental in covering large
tracts with sand, gravel, and till, thus preventing the solution of many
important stratigraphical problems. The surface deposits, as represented
by colors upon the map, cover more area in this district than in any of
the others. While this prevents so full a knowledge of the solid rocks,
it enables us to carry on successfully the study of surface geology, as
will appear in the sequel.

The following formations crop out in the Coast district, including the
adjacent portion of York county. Me., and a little of Essex county, Mass.,
so far as represented upon the south-east part of the map: i. Porphyritic

6l2 STRATIGRAPHICAL GEOLOGY.

gneiss. 2. Lake gneiss (including the Laurentian of Massachusetts)
3. Montalban. 4. Rockingham group. 5. Merrimack group. 6. Kearsarge
group. 7. Huronian and Cambrian of Massachusetts. The unstratiiied
rocks are the sienites of Exeter and Pawtuckaway, inferior granites, and
the well-developed granites and porphyries of York county, besides a
great many trap dykes along the coast.

I. PoRPHYRiTic Gneiss.

Only a relic of this ancient formation appears in this district, and that
is at the extreme south-eastern corner, in Seabrook. It lies at the north-
east end of the sienitic range. The crystals are small ; and the rock is
traversed by segregated veins. Perhaps it had better be ranked with
the eruptive mass of Green mountain, or with the Lake gneiss. Its
association with the sienite reminds one of the like condition of things
to be described presently in Brentwood. The ledges appear in the salt
marsh region near the mouth of Little river, and are frequently covered
by the tide.

2. Lake Gneiss.

Five principal areas of this formation may be mentioned in this field :
(i) in the corners of Barnstead, Alton, New Durham, and Farmington;
(2) Strafford and Northwood ; (3) Barrington to Candia, connecting with
the Deerfield-Mason range; (4) the Hampstead range, with the small
patches in Chester, Epping, and Fremont ; (5) the north end of an
ancient range from Massachusetts, terminating in North Andover and
Boxford.

The Barnstead and Northwood Areas. These are isolated patches,
almost on the same line of outcrop, each about eight miles long. The
first is mainly restricted to the elevation known as New Durham ridge,
there being a small village upon the summit. At school-house No. 3 the
gneiss dips 5° N. W. By the Free-will Baptist church, at the very high-
est point, the layers are exceedingly twisted, with micaceous and ferrugi-
nous seams, dipping 20° S. E. Coarse granite veins twenty-one feet wide
cut the strata. At L. S. Nute's, in Alton, the dip is S. 30° W. For a
mile or more the north-west strike predominates. At J. Morrison's the
dip is south-east. Drift covers the ledges on the north side of Half-

GEOLOGY OF THE COAST DISTRICT. 613

moon pond, and the outcrop is obscure near G. Hill's. Near the west
line of the town, west of T. Hill's, the strike is north-east. These
observations indicate great irregularities: first, a synclinal cast of New
Durham church ; an anticlinal to the west, before reaching Alton ; and
a possible synclinal in Alton. The strike conforms with the ridge, north-
west, a part of the way, which is an unusual course. In Strafford, the
band crops out a mile east of Bow lake, in district No. i6, the gneiss near
by dipping 45° N. W. On the eastern side of the lake, farther north, the
vertical strata run N. 20° E., and others dip N. 40° W. near by. This rock
occupies the north part of Northwood, at the " Narrows," and about Bow
and Long ponds is believed to dip westerly. The stone at the Bow lake
outlet dam is well-defined gneiss, and comes from a quarry to the west of
the village. No ledges except gneiss were met with between the outlet
and East Northwood, and also from the same beginning to the west cor-
ner of Barrington. North of James Crawford's, in Strafford, the gneiss
dips south ; a little to the south is a fine, dark colored variety, with the
inclination S. 20° E. Close by the small pond in the west corner of Bar-
rington is a knob of coarse, hard granite, seemingly the prevailing rock
for a mile into Nottingham.

Barrington and Candia Range. It is probable that most of Barrington
is underlaid by gneiss, while observations respecting it are very meagre.
It is the north-east end of the Manchester band of the Merrimack dis-
trict, and does not extend into Rochester. The town consists of hills of
coarse granite, not of large size, with schists between in the valleys, the
latter having suffered the most from denudation. The specimens col-
lected from. Section IV resemble the Montalban series. In the south
corner of the town, near E. Randall's, is gneiss ; and at school-house No.
9 it dips south-east. At Thompson's, close to the Nottingham line, well-
defined gneiss dips S. 60° E. At a saw-mill half a mile west the same
rock occurs. The low country to the west reveals similar ledges, as at A.
Witham's, dip S. 80° E., and near the Baptist church. There seem to be
mica schists in the north part of Nottingham, but most of the west part
of the town is believed to be underlaid by this gneiss. There are a few
ledges of it between the north outlet from Pawtuckaway pond and the
west town line. In Deerfield there are similar ledges on the road from
the Square to the Parade, and on the height of land coming very close to

6l4 STRATrORAPIlICAL GKOI.OOy.

sicnilc. No observations liavc been taken between this road and Saddle-
back niounl:iin, in Noilliwood. Iktween the two vilkif^es of Dcerficld is
a coarse mica schist, of the kind associated with the gneiss. The north-
ern boundary of the latter rock is irre^^ular throii{;h this town. Granitic
gneiss hummocks abound east of the ('entre, dip north-west. At the
cemetery, sf)uth of S. V. Rollins's, the dip is north-west. The same at
the brook a mile south. The north-west part of Raymond belongs to the
gneiss. The boundary line between it and the mica schists may be
drawn from the south end of I'awtuckaway to a little below Jones's pond,
and then direct to Massrd)csic lake. At C. G. Smith's, near the north
line of l\.aymond, the dip is north-west ; as also in the south-west part of
Nottingham. From Jones's pond to the west line of Candia the rock is
the twisted gneiss of Manchester, and there is a synclinrd axis in the east
part of Candia, followed by a very marked anticlinal in the central part of
the town. A short distance north of the depot is the south-east dip; but
it is lo the north-west at Candia village. The axis has not been traced
farther to llic north-east. Its course, as mentioned on a previous page
(560), would, if continued, proceed to the sicnitic eiuptive mass of the
I'awtuckaway mountains. The south-east jiart of Candia contains many
gneiss ledges, particularly on T'atten's hill. Rattlesnake hill, in Raymond,
is of this materia], and may be an isolated fragment. There is a similar
one of unknown extent near D. liall's, in the south-east part of Auburn.

There is a small area of gneiss in the north part of Chester, consti-
tuting a large hill. 'J'he strike is N. 55" K. in the south j)art of it, and
the dip N. 30° W. on the summit. It crosses the road near a school-
house, more than a mile west of the village. We find the same rock
farther north-east, bolli in Clicslcr and RaynK)nd, but it does not seem to
connect with the West J^i)ping exposures. The latter crop out by the mills
on the Lamprey river in vertical strata, with the course north-cast and
south-west. A large number of loose blocks of this gneiss are spread over
the plain near the station. Drift covers the natural continuation of the
range in the south part of l'>pi)ing and the north part of JM-emont; but it
appears near D. Rowc's, west of the village, and in the south-west part of
the town dips S. 75° E. These observations indicate the anticlinal struct-
ure in this area. The town of Sandown has not been explored yet, so that
the representation upon the map is based only upon probabilities. The

GEOLOGY OF Till'. COAST DISTRICT. 6\ $

projection of all Iho fucL.s at comiiiaiul ccrlainly siip^f^csts tlic direct con-
nection of the ICpping and Fremont gneisses with the JIampslead area.
In Brentwood a few ledges of this gneiss, dipping 70" S. 60" W., with
joints inclined S. 40'' K., appear to the east of a Congregational (iiiirch,
more than a mile west of Marshall's corner. It adjoins sienile, and does
not extend far along the line of strike.

Massac// r/.u-t/s Area. The map i)resents to view seven or eight miles'
length of the north-cast end of a very important gneiss band, called
Laurentian by some, and designated as Atlantic upon i'late I. It is
noted upon page 23 as forming the outermost of the formations encir-
cling the Boston basin concentrically. 'Die section (I'late 11) gives it a
monoclinal north-west dip. Concerning this gneiss in Andover and
North Andover, I wrote the following in i<S67,* including a notice of a
very coarse granite :

The gneiss foimalion includes ;in ii;;ly I<)()kin<i; gneiss,— a very (cniii^inous variety, —
quartzites in limited amount, nnicli rinc-j^Maincd j^rauitc^ a bed ui slcalilc, and jicrliaps
Other varictie.s worthy of notice. It occupies most of the area of tiie two towns, lyin;^
north-west of the hornblende rock, and limited by an overlyinj^ mica schist on the Mer-
rimack river. South of Aslcbc hill is a fine-grained granite, uui. far Irom the steatite
bed atW. Jenkins's .saw-mill. 'I'lic first ledge oljservcd wcstof Asiebe hill is (|iiarl/,ile.
Patches of the fine-grained granite were noted at J. Cummings's, near Carmel hill ; in
small amount at the railroad station at .South Andover; near J. Adams's, on the south
shore of North Andover pond ; several localities south-west from the West Andover
cemetery; at about three fourths of a mile north from West Andover church, at J.
Chandler's, near the almshouse, and in many other places. There may be a .synclinal
structure in this formation, for at the South Andover station the dip is 80° N. 67^ W.,
and 46° S. E. west of West Andover church. In several other places east of Shaw-
sheen river the north-westerly dip was noticed ; and it is my impression that the south-
easterly dip prevails in the railroad cut at South Lawrence. Along the north-western
boundary of this group there is a belt of peculiar gneiss, whose feldspar has the appear-
ance of small pebbles. I am uncertain whether it belongs to the gneiss below, or to
the mica schist above.

The coarse granite apjjears on the map like a flattened ellipse, with sharp ends cut-
ting the gneiss at an angle of about twenty-five degrees. 1 have not searched for it
south of Foster's pond ; but to the north from that point, as far as IJ. Rogers's in the
north-east corner of the Phillips district, the outcroi)s are very numerous. From the
middle of Scotland district to a point west of Moses Abbott's, nearly a mile and a half,

* Proc. Essex Institute, vol. v, p. 157.

6l6 STRATIGRAPHICAL GEOLOGY.

this rock forms a high, precipitous ledge, of which the culminating point is Sunset Rock.
The buildings of the Theological Seminary appear to be on the boundary between the
coarse granite and the gneiss to the west. The most easterly outcrop of the coarse
rock is near Simeon's, west of H. Gray's, in the Holt district. The length of this
granite is a little more than four miles, and its greatest width 440 rods. The crystals
of mica and feldspar are sometimes six inches broad, and are universally very large.

This area carries beds of limestone, in which Eozoon has been found,
as at Chehnsford, by L. S. Burbank.* The same fossil occurs at New-
bury. The occurrence of the Laurentian and associated rocks in this
town will be found further described under the topic of Economical
Geology.

3. MONTALBAN.

In Farmington is an area of excellent Concord granite, two or three
miles long, occupying the valley of a large tributary of the Cochecho river.
A hill back of the railroad depot is composed of the same material. The
drift is so extensive to the north of it as to make it uncertain whether
this area may directly join the Lake gneiss of New Durham, or be sep-
arated by a covering of mica schist. This series, without the granite,
crops out extensively in Sanford, Alfred, and the adjacent towns farther
north in Maine. There is a synclinal axis in it near Springvale.

4. Rockingham Mica vSchist.

This may occupy more space in this district than any other group.
Two areas may be noted, united to each other in Rochester. The first
is the continuation of one previously described, and extends from Aliens-
town to Alton, and to near Newfield in Maine. The second joins the
Nashua deposit, previously noted, and may be followed adjacent to the
Nashua & Rochester Railroad to Berwick, Me. The following positions
have been noted in the first area:

Gilmanton. At J. L. Page's, dip 45° N. 50° W.

At S. C. Place's, dip 65° N. 20° E. On Grant hill, dip 25° N. 80° W.

At J. D. Nelson's, dip 30° N. 20° W. At east base of Lamprey hill, dip irregu-
At J. F. Nelson's, dip 57° N. 5° E. larly 30° N. E.

At D. B. Morrill's, dip N. 30° W. On Hall's hill, south-cast corner, dip N.
West of D. B. Morrill's, dip 10° N. 60° W. 60° W.

* Proc. Boston Society Natural History, vol. xiv, p. 190.

GEOLOGY OF THE COAST DISTRICT.

617

North of Mrs. J. Gilman's, granite beds,

dip N. E.
West of Cogswell hill, dip 25° N. 70° W.
At T. J. Gale's, dip 25° N. 60° W.
At Iron Works village, east edge, dip small

N. W.
At tannery south of Butler brook, 45° S.

25° E.

Banistead.
At T. Edgerly's, dip E. i5°-20°.
At W. Jenkins's, Jr., dip S. W.
At J. Blake's, dip 50 N. 85° W.
At Clarke's corner, dip 30° southerly.
At S. Lougee's, dip 70° S. 30° E.

Alton.
At J. Morrison's, hill west of "Bay," dip

70° N. 50° W.

Afew Du7-}iaiii.
At brook, east part of town, dip S. W.
At W. H. Tush's, near corner, dip 80° S.

25° E.
At G. D. Savage's, dip S. 75° E.
I mile north-west from corner, dip N. 20.

W.

Northwood.
At north-east corner, dip N. 30° W.
At east border of Jenness pond, dip 60° W.
South-east from Suncook pond, dip S. 40°

W.
On Saddleback mountain, dip N. W.
At L. Durgin's, north base of Saddleback

mountain, dip 25° W.
Milt 071.
At mills, dip 12° S.
At W. F. Cutts's, dip 20° S. 5° W.
At school-house No. 8, dip 12° N. 10°

At N. H. Roberts's, dip 25° N. 40° W.
At town line, next Wakefield, dip N. 80°

W.
At top of Teneriffe mountain, dip 60° W.
At W. W. Kicker's, dip S. 50° W.
On west side of Milton pond, 65° N. W.
At Three Ponds village, dip S. E.
At South Milton, dip 70° N. 30° W.

FarviingtoH.

At J. A. & L. T. Tibbitts's, dip north-east-
erly, small.

The same at saw-mill in school districts
Nos. II and 12.

West of O. K. Otis's, dips S. 20° E.

At O. K. Otis's, dip S. 50° W.

North of the above, dip N. 50° E.

At G. F. Nutter's and J. B. Lyman's, dip
S. 60° E.

On Chesley mountain, west side, dip S. E.

At Merrill's corners, dip 80° N. 40° W.

Strafford.
At school-house No. 11, dip 15° N. W.
At B. Hayes's, dip 45° N. 60° E,
At C. E. Evans's, dip S. 70° E.
On top of Blue hills and at T. & C. Cas-
well's, dip S. 80° E.
At D. P. Caswell's, dip S. 80° E.
At "Corner," dip N. 50° W.
At S. Young's, dip N. 40° W.
At A. H. Cater's, dip N. 40° W.
At J. Mills's, top of ridge, dip S. 20° E.

Deerfield.
At north-east corner, dip 85° S. 70° W.
East of E. R. Rowell's, dip N. 70° W.
At W. T. Smith's, dip S. 40° E.

The second area mentioned is hardly to be separated from the Merri-
mack group, save as certain parts of it closely resemble the typical Huro-
nian. The following positions have been noted :
VOL. II. 78

6i8

STRATIGRAPHICAL GEOLOGY.

Auburn.
At P. Preston's, strike N. 70° E.
East of Devil's Den, dip N. 5° E.

Chester.
At C. Chase's, dip 80° S. 30° E.
At I. Forsaith's, dip 75° N. 40° W.
At Cliester village, dip vertical.
At Wm. S. True's, dip 50° S. E.

Epping.
At I. F. Norris's, dip 70° S. 75° E.
At A. Randlett's, 80° S. 75° E.
North of J. French's, 80° S. 75° E.
At school-house west of French's, 70° N.

85° E.
Between Gov. Prescott's and the village,

dip S. E.
Near J. Ely's, dip 70° S. 80° E.
At J. P. Chase's, dip 70° N. 70° W.
At B. Dow's, near railroad, vertical, strike

N. 30° E.
On Red Oak hill, dip N. W.
In north-west part of Epping, dip N. W.
At railroad cut h. mile south of Junction,

dip 75° E.

Danville.
At Wm. Bagley's, dip 45° N. 60° W.

Newmarket.
At E. Hilton's, vertical, north-east strike.

Nottingha7n.
At North Corner, dip 45° E.
I mile north of S. Priest's, dip easterly.
At S. Priest's, dip westerly.
At J. C. Tattle's, dip S. E.
Near Epping line, dip 90° ; strike, N. and

S.
At J. Gile's, dip S. E.
At Tannery near J. Hill's, dip N. W.
Half mile west of tannery, dip N. 20° W.
At G. Marston's, dip S. 20° E.
West of square, dip north-westerly.

At B. P. Harvey's, near Epping line, dip

north-westerly.

Dover.
City, dip north-westerly.

Raymond.
Near pond west of village, dip 70° N. 40°

W.
North of village, dip 55° N. 35° W.
At B. Dearborn's and quartz, dip 75° N.

W.
At cemetery south of railroad, dip 80° N.

50° W.
Near A. Brown's, south-west part of the

town, dip 90° ; strike N. 40° E.
Quartz east of village, dip 70° northerly.
East of above, dip 70° N. W.
At S. Blake's and J. Brown's, north-east

part of the town, dip N. W.
Near Raymond depot, dip 55° N. 20° W.
Near L. Moulton's, east and west strike.

Fremont.
At J. Morrill's, dip 80° S. 80° E.
Near D. Beede's, dip S. E.
Near O. B. Poor's, dip 80° N. W.

Brenttuood.
At north-west corner, dip N. W.
At S. Fuller's, dip 88° N. 10° W.
At nurseries by west line, dip N.
At Ladd's mill, south-west corner, dip 40°

N. W.
At Crawley's falls, dip 55° N. W.

Lee.
South of C. H. Tuttle's, dip 80° N. 60° W.
At Wadley's Falls, dip 40° W.
At school-house No. i , dip 65° N. 40° W.
At M. Thompson's, dip N. 45° W.
At O. Davis's, dip 50° N. 50" W.
At S. W. Bateman's, dip 85° S. E.
At Jas. Gile's, dip 85° N. W.
South of J. P. Haley's, near Epping line,

dip 850 N. W.

GEOLOGY OF THE COAST DISTRICT. 619

Sotnersworth. Rollinsford.

Near Smith & Roberts's, dip southerly. At S. Hale's, dip 65° N. 70° W.

At Great Falls academy, dip 70° N. 30°
W.

Of the several axes indicated in this list, perhaps the most important is
the continuation of the anticlinal from the Hampstead gneiss through
Sandown, Fremont, and Epping into Nottingham. This seems to con-
nect the different gneisses together, placing the Nashua and Raymond
schists in a separate stratigraphical district from those of Epping, Dan-
ville, etc. Through Fremont and Epping we get evidences of a well-
marked synclinal, perhaps terminating in Nottingham. Through Fre-
mont and Brentwood this is a natural basin between ridges of gneiss.

Between the Raymond and Epping sides of the anticlinal are marked
differences in lithological composition. In the former area is a rock
much like the typical Huronian, with its dolomites. They occupy a con-
siderable space in Raymond, characterized by an almost east and west
strike. Similar ledges have been noticed in the north part of Derry,
north of Beaver pond (pp. 581,582). There is a related rock more than
a mile wide in the south-east part of Auburn, which seems like the
natural continuation of the Raymond belt. On the Epping side nearly
all the exposures consist of gray micaceous quartzite and mica schist, not
different from the common variety of the Merrimack group. The mica
schists on the Raymond side are coarser and less siliceous. Perhaps this
axial line ought to be employed on the map as the boundary between the
Rockingham and Merrimack group.

A few facts of interest respecting the rocks over this area are the fol-
lowing: In Auburn, north of the Devil's Den, at J. Calef's and R Pres-
ton's, the schists are cut at an angle of eighty degrees by a vein of
granite. East of the den are many large white beds of granite. The
den itself seems to be a knob of mica schist. The south part of Auburn
is largely occupied by drift, and the most easterly outcrop of Lake gneiss
is by D. Ball's, perhaps an outlier. I do not find mention made of bedded
granites in the west part of Chester. The quartz bands have a large
development, being nearly continuous from a mile south of Raymond vil-
lage to Nottingham square. This principal band crosses the railroad east
of Raymond village, and there is a smaller one about a mile west of the

620 STRATIGRAPHICAL GEOLOGY.

depot, coming up in connection with a very coarse granite. The princi-
pal range rises to Flint hill, in the north part of the town, then falls oppo-
site the Pawtuckaway river, and rises to view with a north-west dip at
several places in Nottingham. In Lee, near M. Thompson's, is an un-
usual display of similar boulders, as if their source could not be far dis-
tant. There are ledges of this rock in the other area in Northwood,
on the east side of Pleasant pond, with a northerly course. It does not
yet show itself to the east of the main anticlinal. The bands observed
must belong to a later formation than the typical ranges in Hillsborough
county.

The granitic masses are unusually large in Danville, being more than a
mile wide east of Wm. Bagley's. In the area lying partly in Danville and
partly in Kingston, between Long and Half-moon ponds, the granite con-
stitutes something of a hill. The granites of this group are mostly want-
ing in Fremont, Brentwood, and Epping. The same is true of the south
part of Nottingham, Lee, and Madbury. In Somersworth there is a large
granitic area, in the north part of the town, possibly of eruptive character.
In Dover, at Sawyer's mills, the schists are well exposed in a railroad ex-
cavation, and bear marks of strong pressure, with many small slickensides.

The Rockingham group in Hillsborough county is characterized by
orographical features, as exemplified by the presence of a mountain range
commencing with Kidder and Temple, continued in Pack Monadnock
and the Lyndeborough hills, and preserved farther north-east in the soli-
tary pile of the Uncanoonucs. The Merrimack valley brings up the older
gneisses, and as soon as we pass a few miles to the north-east this ele-
vated range reappears very prominently in the four mountains of Epsom,
— Brush hill, McKoy's, Fort, and Nottingham mountains, — Catamount
in Pittsfield, and then there is a range just a little farther to the south-
east, consisting of the Blue Hills range in Strafford, Blue Job, Nubble,
Hussey, and Chesley mountains in Farmington, and Teneriffe in Milton,
These disconnected portions of a once continuous range suggest eleva-
tions of the underlying formations along what are now valleys of denuda-
tion, and the subsequent wearing away of the mountains of mica schist
now needed to fill up the gaps in the range.

GEOLOGY OF THE COAST DISTRICT.

621

5. Merrimack Group.

Under this head we may continue the description of the last part of
the preceding, or what agrees with it hthologically, but in a different
geographical field. This territory embraces all the schists usually re-
ferred to the Merrimack series on the south-east side of the principal
sienitic range, passing through Exeter, and what lies south-east of the
Pelham gneiss. Viewed in its entirety, it may be said to occupy the prin-
cipal area between the Exeter and Newburyport ranges of sicnite, as well
as that between the two great gneiss areas of Pelham and Andover. This
is the typical area of this group, from which the name was derived. The
rock is mostly a micaceous quartzite, varying to argillaceous schist, and
frequently reminding one of the rock carrying Paradoxidcs in Massachu-
setts. We have the following observations of its position :

Massachusetts.
In Andover, along Merrimack river, dip

50° N.
At North Andover, generally, dip 30°-4o°

north-westerly.
In Dracut, south of Peter's pond, dip 60°

N.
At Lawrence post-office, dip 70° N. 80° W.
In Methuen, north part, dip 20° N. W.
In Bradford, on B. & M. R. R., dip 25° N.

50° W.
In Haverhill, dip generally about N. 60°

W.
In Boxford, dip 25°-6o° N. W.
In Salisbury, dip N. W.

Plaistoiv.
At J. Noyes's, in east part of town, dip 80°

N. 80° W.
At S. Calden's, dip 80° N. 80° W.

Atkinson.
Near school-house in east part of town, dip

50° N. 60° W.
Near D. Noyes's, north corner, dip 50° N.

60° W.

Hampstead.
At S. Harris's, dip S. E.
At J. Bradley's, dip vertical, or 80° S. E.
At E. Morse's, dip S. 80° E.
At S. Dow's, dip S. 80° E.
At the town hall, too variable for measure-
ment.
At J. E. Emerson's, dip 50° N. 30° W.

Newton.
At east part of town, dip 80° N. W.
At N. Gould's, dip 55° N. W.
At M. Bartlett's, dip 50° N. 70° W.

Sojith Ki tigs ton.
At E. Hunt's, dip S. 60° E.
South Hampton.
Near west line, dip 85° N. W.

Seabrook.
North of church, dip 80° S. 10° W.
Near school-house east of the railroad, be-
tween villages, dip 80° N.
Hampton Falls.
At W. W. Healey's, dip N. W.
At Baptist church, dip N. W.
South of village, dip S. E.

622

STRATIGRAPHICAL GEOLOGY.

Hampton.
At school-house east of "Wolf hill, dip N.

W.
At Mrs. C. Leavitt's, dip vertical.

North Hampton.
At S. Brown's, Jr., dip vertical.
Near Little Boar's Head, dip 70° N. 40°

W.
At J. S. Hobbs's, dip 55° N. 80° W.
At T. Hobbs's, Jr., dip N. 40° W.

Rye.
At W. Holmes's, dip 65° N. 40° W.
At C. S. Jones's, dip 65° N. 60° W.
At W. W. Seavey's, dip 70° N. W.
At Sagamore house, vertical, N. 40° strike.
At Frost's Point, dip 65° N. W.
On Breakfast hill, dip 75° N. 30° W.

Newcastle.
At north end, dip S. E.
Generally, dip N. W.
At south end, dip 50° N. 50° W.

Stratham.
At G. Lane's, dip N. W.
At north base of Stratham hill, dip N. W.
At J. Thompson's, dip 50° N. 75° W.
At N. Chase's, dip 50° N. 75° W.

Greenland.
At Brackett's crossing, dip 70° N. 40° W.
A mile north of Greenland church, dip 50°
N. 40° W.

Newington.
At E. Coleman's, dip 60° N. 50° W.

Rollitisford.
At L. Stackpole's, dip N. W.
At S. Hale's, dip 65° N. 70° W.

Maine.

In Kittery, next Portsmouth, dip 85° N. W.

In York, at Long sands, dips 80° S. 40° E.

and N. 50° W ; also at a less angle to

the north-west.

Near Kenncbunk river, north-west strike.

Portsmo7ith.

Near bridge at south mill-pond, dip 50°
north-westerly.

A mile south of post-office, dip 70° N. 20°
W.

At bridge over Sagamore creek, dip 70° N.
25° W.

East of railroad intersection, dip 45° N.
35° W. and 55° N. W.

At S. Tacker's, dip S. E.

At A. W. Simpson's, etc., dip N. W.

North of Sagamore creek on road to Break-
fast hill, 80° S. 50° E.

At T. Lightfoot's, dip 60° N. W.

At A. Holden's, near S. line, dip N. W.

At Jos. P. Marden's, dip N. W.

On Goat island, dip S. E.

One fourth mile west of Newcastle bridge,
vertical, strike N. 55° E.

At school-house north of north mill-pond,
dip 85° S. 20° E. and 80° N. 20° W.

Between Eastern Railroad depot and Con-
cord Railroad wharf, dip N. W.
Exeter.

At south edge of village, on branch of the
Exeter river, in two places one mile
apart, dip 80° W.

At Exeter river, east of village, dip N. W.

In north-east part of the town, dip 80° W.
South Newmarket.

East of Junction, dip 70° N. 70° E.

Much the same through Newmarket.
Durham.

All along the shore of Great bay the dip is
usually 80° N. 60° W.
Dover.

At "Point" near T. Couch's, dip 80° W.

At Mrs. Coleman's, dip 70° N. 70° W.
Star Island.

Strike N. 40° E. ; dip variable.

GEOLOGY OF THE COAST DISTRICT. 623

In the east corner of Plaistow, quite near the railroad, is a large mass
of granite, thought at first to represent the porphyritic gneiss. At J.
Noyes's, a prominent set of joints clip 35° N. In the east part of Atkin-
son coarse granites abound at L. Darling's. Smaller beds are scattered
through Hampstead. The schists seen in a trip through the east part of
Plaistow and Hampstead were thought to be more like the Rockingham
than Merrimack. A fine-grained granite has been observed on the high-
est land on the west side of Country pond, at South Kingston, which is
probably continuous with a similar rock on a north-west ridge in East
Hampstead, visible for half a mile. The course of this mass would be
about east and west, not agreeing with the strike of the schists. In the
very west corner of South Kingston are large beds of coarse granite.
Kingston is mostly covered by sand, but there are indications of a schis-
tose ledge in the north-east corner of the town. There are a few out-
crops of unclean ferruginous schist near Mrs. Morrill's, in the south-east
corner of East Kingston. Almost the only ledge found in South Hamp-
ton occurs on a hummock close by the west line of the town. It is a
gray quartzite, breaking into innumerable pieces in consequence of ex-
posure to frost. In Seabrook there is more variety. North of the vil-
lage ferruginous quartz and flinty slates are interstratified, traversed by
a peculiar porphyritic diorite. Other trap dykes occur at the village, and
at a school-house east of the railroad. Half a mile west of Seabrook vil-
lage there is a granite mass. At a Baptist church in Hampton Falls the
rock is a gray sandstone, easily mistaken for sienite at a little distance.
Two miles north the slates are friable and decompose easily. Trap
occurs at the school-house east of Wolf hill, and north of Little Boar's
Head, in Hampton.

About Portsmouth the ledges are well displayed. There seems to be
a synclinal axis from the south end of the town through to the north end
of Newcastle. The anticlinal on the north is very near to it. Bands of
gneiss or indigenous granite are quite conspicuous in this and the adjoin-
ing towns. One of the most prominent is Breakfast hill, perhaps an anti-
clinal. This band crops out north-easterly at the railroad crossing in the
extreme south part of the town, near J. Marston's, T. Lightfoot's, and north
of Sagamore creek, on the Telegraph road. It also appears just north
of the same creek on the road to Frost's point from Portsmouth, on a

624 STRATIGRAPHICAL GEOLOGY.

parallel band, and near D. D. Whidden's in Ward No. i. There must be
many others. Near the south end of Newcastle the origin of these gran-
itic beds is apparent. They have been formed by the alteration of sand-
stones in situ. There is nothing indicating disturbance in these beds,
while there is a freshness about the mica crystals. None of the larger
beds are probably over 200 feet in breadth.

Dr. Jackson examined the rocks about Portsmouth. A few sentences
are extracted from his report, stating the phenomena in his own language :

The rocks to which I refer are the dark blue flinty slates, possessing an imperfectly
stratified structure, a very compact texture, sonorous when struck by the hammer, and
often breaking with a more or less distinctly conchoidal fracture. Occasionally they
evince a passage into an imperfect micaceous slate, especially where they border on
granitic rocks. * * Another change is also observed in the flinty slate rocks near
the railroad cutting in the vicinity of Portsmouth. The rock is filled with an infinity
of reticulated veins of carbonate of lime. This may have been produced by the fusion
[infiltration] of calcareous matter contained in the rock by the action of heat. * *
Iron pyrites abound in this locality. * * The strata of flinty slate are much con-
torted; and this contortion took place,. evidently, anterior to the eruption of the trap
dykes. The flinty slate contains numerous veins of compact feldspar, which probably
were formed at the epoch of the elevation of the granite rocks. * * The joints are
generally in directions parallel to those of a rhombic prism. * * The flinty slates
are succeeded by granites, which in numerous places have been erupted so as to isolate
portions of the slate by intrusion between their masses. Such phenomena would give
to a casual observer the idea that the slates and granite alternate with each other. It
will be found on further observation that such is not the case, for the primary rocks
have merely been forced in between portions of the slate. Near the house of Samuel
Langdon, a mile and a half from Portsmouth on the road to Boar's Head, a mass of
granite has been intruded through the slate, and occupies a considerable area, beyond
which the flinty slate again appears, and then gives way to a regular granite and gneiss
formation, which extends through a large portion of Rye. In Portsmouth the intrusion
of granite veins and trap dykes into the flinty slate may be seen in Shoar's woods.

The Isles of Shoals have been neglected. I have noted the fact of the
presence of gneiss on Star island, without stating which is the predomi-
nant dip. The following brief notes about them are taken from Jackson.
Star island is said to be composed of a coarse variety of granite, having
large crystals of white feldspar, gray quartz, and but little mica, with
intercalated beds of mica schist. Along the middle of the island is a
trap dyke running north-east. There is very little soil upon the island.

TLJ^TElcx^r,

■'^'

/ o/\ M E Ro^R I M A cj):<. G RO U P.

Merrimack
Group.
ExtTER SlENITt. ^ ^

Fig 106. From Fawtuckaway Fond to Exeter Village.

J

V

0^

V

Jr

"'^^^Merrimack ^ Merrimack v^ ^t« ^
ySi Group. <.^ Group. /> vY /

i

T

-^3

EHITE.

5

^i-?rrry^^

J

Fig. 107. From Brentwood to Seabrook.

/

y

f

^o^R.OCK(MGHAM

^^ Group.

An dalusite

5cm isx.

il4 /

/

LB AN

Fig. 108. From Milton Mills to Alfred, Me.

^ M ^R

/

R I M /Ij^C K

^

fTUT¥i^

FuAagsa"

^:^^rmmmrmr!mmr,^wmn^\-^:ss^

f/

J An D ALU S.<-ITI

Fig. 10^. From Salem to N.Ando\^er,Mass. FiG.llO.lNFARMiNGTON and Rochester.

SCALt-^HORIZO/VTALLf, 2iMILES TO AN INCH; VeRTICALLV , 2000 FCST TO AN INCH.

GEOLOGY OF THE COAST DISTRICT. 625

Hog island is composed mostly of mica schist. Duck island shows gran-
ite and gneiss. The other islands arc granitic.

The most modern-looking rocks I have seen are situated in a cut by
Brackett's station on the Portsmouth railroad. Geologists familiar with
Cambrian fossiliferous strata would find many ledges in the east part of
Rockingham county very similar to those yielding trilobites, worms, and
mollusca elsewhere. Careful search will undoubtedly develop them here-
after.

Kittery, York, and Eliot, Maine, are a continuation of these slaty
quartzites of the Merrimack group, and they follow up the Newichwan-
nock river between the two sienite areas to Berwick. Similar strata may
be followed along the coast nearly to Portland. On the Kennebunk and
Saco rivers are areas more argillaceous, possessing a north-west strike.
This fact suggests the existence of later groups resting uncomformably
upon the Merrimack series, similar to the Cambrian along Parker river,
Massachusetts.

Great bay must be underlaid by these rocks, as they yield to decom-
position sooner than the hard sienite. One would naturally expect to
find a shallow synclinal beneath the water of Great bay, but the strata dip
at large angles, though showing the basin form. From Exeter village to
South Berwick the slates occupy only a small space adjacent to the water,
being a fringe skirting the sienite. What irregularities of position be-
tween these rocks have been perceived, are represented upon the map.
These may, perhaps, have arisen from igneous ejections, accompanied
with lateral pressure. A like irregular boundary may be seen in York,
Wells, and farther along the coast of Maine.

Plate XXV illustrates the relations of the Merrimack group to the adjoining forma-
tions. Fig. 106 shows the order of rocks between Pawtuckaway pond and Exeter vil-
lage. At the west end in Nottingham are the north-westerly dipping mica schists,
carrying the quartz band. Then appears the most important anticlinal, dividing the
group naturally into two parts, followed by unimportant flexures and the Epping syn-
clinal. The sienite of Exeter occupies an important place at the east end of the sec-
tion, seemingly supporting the slates ; and the high westerly-dipping schists at the east
side of the village would seem to indicate an inverted anticlinal, when compared with
those on the other side of the sienite.

Fig. 107 gives an insight into the relations of the strata between Brentwood and Sea-
brook. In the first-named town there is an area of gneiss adjacent to the sienite.
VOL. II. 79

626 STRATIGRAPHICAL GEOLOGY.

This seems to be a more natural association than between sienite and the schists.
The discovery of the gneiss here has raised the question whether it may not be
the usual floor of the sienite. Sometimes the latter is traversed by planes like those
of stratification, but they have not been carefully traced out in this region. The
sienite through Exeter is quite broad. Then we have north-westerly dipping schists
of the Merrimack group, followed by a narrower band of sienite in the north part of
Hampton Falls. At the Baptist church is the gray feldspathic member, perhaps con-
tinuous with one of the granitic beds of Rye or Portsmouth. Seabrook shows more
variation in the dip, with a bit of sienite and ancient gneiss at the eastern end.

Fig. io8 illustrates the country between Milton Mills and Alfred, Me., properly con-
nected with the previous chapter, and the continuation easterly of Section V. The
first rock is the Rockingham mica schist, with south-westerly and westerly dips. A
small anticlinal occurs near school-house No. 6 of Acton, where the dip changes back
to north-westerly, and the rock is quite ferruginous. Next occurs the andalusite mica
schist of the Kearsarge type, not differing greatly from that already passed over. There
is a knob of granite on it at its west edge. East of South Acton post-office the dip is
10° N. W. About a mile before coming to Mousam pond is a siliceous limestone with
gneiss, dipping 5° S. W. This is thought to belong to the Lake series. In the neigh-
borhood of Emery's mills in Shapleigh, ferruginous schist of Montalban type dips irreg-
ularly 50° S. 80° W. About Spring Vale in Sanford we have similar rocks, with a
synclinal axis, the west dips prevailing from the town line. Just in the edge of Alfred
the felsite begins ; and at a railroad cut the ledge is distinctly of sienite. The same
rock occurs several times before reaching the village of Alfred, the last being at the
mouth of Middle Branch. At the village there succeeds a fine-grained granite, a
little like that about Merrymeeting lake.

Fig. 109 shows the relations of the Merrimack schists to the adjacent gneisses. The
Salem gneiss has not been observed south of the railroad station, where the dips are
south-westerly (p. 561). Inasmuch as south-east dips prevail along the eastern border
of the gneiss in Pelham (Section I), they are supposed to continue to the place of this
illustration. Near Messer's railroad station the Merrimack schists appear, and are sup-
posed to agree with those measured in the north part of Methuen, dipping 20° N. W.
These rocks are sandy flags, separated by narrow argillaceous seams. At ledges near
Lawrence post-office the strata are vertical. On the northern side of the river are
other exposures. In the railroad cut, 150 rods south from the junction in South Law-
rence, we find the return of the gneiss. It may not certainly be the same with that in
Salem. It contains many rounded spots of feldspar, and several small faults are appar-
ent. The dip is thought to be south-east, and within three miles it is reversed ; and
there is consequently a synclinal attitude to the strata in the west part of the Andover
gneiss. An examination along the strike indicates the presence of a synclinal south of
Lawrence in the Merrimack group, so that three axes seem to represent its structure in
the figure.

GEOLOGY OF THE COAST DISTRICT. 62/

6. Kearsarge Group.

The general character of the rocks of the Kearsarge group has been
stated previously. In the Coast District the rocks differ from the mica
schists of the Rockingham series principally by the addition of the min-
eral andalusite. Hence what has been called Rockingham may prove to
belong to this Kearsarge series after the discovery in it of the mineral
andalusite. One such case has come to hand since the printing of the
sketch of the Merrimack district. Dr. Jackson says he found fibrolite
together with garnets and black tourmaline upon McKoy's and Fort
mountains in Epsom. The principal area of this rock near the east line
of the state occupies most of Rochester, and may be followed into Maine
through Lebanon and Acton into Newfield. In Fig. no is a section
from Chesley mountain, Farmington, to Rochester village, lying partly in
the Rockingham and partly in the andalusite group. This mountain is
part of the series of Rockingham elevations from Temple to Teneriffe.
The strata are much twisted, with a general south-east dip, and the
schists contain beds of granite. Quite near the south base, at M.
Thompson's, are the hard rocks accompanying andalusite schists, dipping
80° N. The same direction is continuous through the rest of the section.
The dips continue high through Farmington, and in the north part of
Rochester become much smaller. At D. Rogers's is a bed of quartz
similar to those in Raymond. The section shows a sharp synclinal in
the andalusite schists resting unconformably upon the Rockingham. As
the dip is greater in the south part of the town, were the section pro-
tracted farther we might add an anticlinal to the present delineation.
The following observations of dips in this area have been preserved, not
repeating those already mentioned:

Rochester. At R. T. Rogers's, dip is<=' N. 50° W.

At school-house No. 17, dip 50° N. 40° W. In East Rochester, dip 55^-60° N. 60° W.

At D. G. Ricker's and the brook east, dip In Gonic, dip south-easterly.

65° N. 10° W. At railroad near Mrs. Trickey's, dip 45° N.
The same at J. Foss's and H. Evans's. 10° W.

At F. Gray's, in north-west corner of the At Mrs. Pike's, in school district No. 20,

town, dip 85° N. 10° W. dip 10° N. 10° W.

At Jas. McDuffie's, dip 15° N. 25° W. At Hayes's crossing, dip 30° westerly.

628 STRATIGRAPHICAL GEOLOGY.

Farviington. At H. Lord's, dip 45° N. 60° W.

At Mrs. B. Willey's, ferruginous, dip N. At Lebanon post-ofFice, several places, dip

W. 50° W.

At MerrilPs corner, dip 80° N. 40° W. At Baptist church, to the south, an anti-

Milton. clinal.

At south corner, dip 30° westerly. Acton, Me.

At South Milton, dip 70° N. 30° W. Half a mile east of South Acton, dip ig°

Lebanon, Me. N. W.

At south corner, dip 50° N. 60° W. At Acton corner, dip 85° S. 50° E.
At C. D. Rankin's, dip 45° N. 60° W.

There is not great opportunity afforded in this table for making out
many axes, otherwise than by inversion. The observation at Gonic would
afford an anticlinal with those farther north. This might agree with the
supposed inverted axis south of Rochester Junction. There is another
in Acton. The rocks have a fresher look than pertains to the Rocking-
ham schists, and perhaps this fact has led us to esteem the andalusite
group the newest, in the absence of the proper stratigraphical evidence.
The analogues of this group in other parts of the state are the Monad-
nock, Kearsarge, Ragged, Mt. Tom, Mt. Washington, and a few other
areas. They seem commonly to constitute elevations resting upon older
metamorphic formations. This last-described area is an exception to the
general rule, as none of it is much elevated. This Rochester area, if con-
tinued, might connect with the more argillaceous portions of the Merri-
mack group in Derry, Nashua, and so on into Massachusetts, to join the
celebrated made rock of Lancaster.

7. HURONIAN AND CaMBRIAN.

The rocks referred to these groups are in the Massachusetts portion of
the south-east sheet of the geological map. There are two areas. The
first is called "hornblende slate" upon the geological map of Massachu-
setts, and lies on the west border of the large extent of sienite of the
Newburyport district, being about eight miles long by two wide. The
second occupies the Parker River basin, and consists of three different
kinds of rocks, all of them unlike anything yet recognized in New Hamp-
shire.

The hornblende schist resembles one of the members of the Huronian
in the Connecticut valley, seen repeatedly between Bernardston and

GEOLOGY OF THE COAST DISTRICT. 629

Orford. Lying upon the west border of the sienite, one might imagine a
gradual passage from the one into the other. The distinction between
them is very clear in the south-east part of North Andover, where the
sienites exist as limited patches of eruptive materials in the midst of the
hornblende rock. This, however, is to the west of the proper field of the
sienite, as marked upon the map. I have examined several exposures of
this hornblende rock in Georgetown and North Andover, and everywhere
see that it is a well-defined stratified rock; and it seems to be like the
Connecticut valley deposits, which border the ancient gneiss in the same
way with this. If we call it Huronian, it would represent the older part
of the system, as it is developed in northern New England. It seems to
be cut off by the Merrimack group, which has a north-easterly course,
while the hornblende runs north and south.

On my father's map the Parker River area is divided into three parts,
the middle called Silurian rocks, the northern porphyry, and the southern
metamorphic slates. In 1859 I crossed this basin along the Eastern Rail-
road, and suggested in the Proceedings of tJie American Association for
the Advancement of Science (p. 118), that the two outer bands might be
of the same age, being the corresponding parts of a synclinal fold, the
northern dipping at the highest angle and considerably altered from the
conglomerates of the southern band. The question of the alteration of
conglomerates into porphyry has been often discussed in the meetings
of the Boston Society of Natural History, and reported in its proceedings.
It is claimed by Mr, T, T. Bouve that the gradual passage of the conglom-
erate into porphyry can be satisfactorily traced out in Hingham and
elsewhere. T do not feel entirely satisfied with the view, because the peb-
bles of the conglomerate are mostly of porphyry, and it would seem there-
fore as if that formation had an existence before the sedimentary rock
had been manufactured. Elaborate field work will be required to settle
the question properly.

The order of the rocks across this basin is the following, from north
to south. At the Devil's Den in Newbury is a mass of serpentine and
limestone of Laurentian age, furnishing well characterized Eoaoon from
a locality a quarter of a mile to the north. The dip is 30° N. W., and I
think there are ledges of gneiss near it. Next are compact porphyries,
not very extensive. They are replaced by red and gray argillaceous

630 STRATIGRAPHICAL GEOLOGY.

schists, dipping 75° N. W. Near the crossing of Parker river are com-
pact green schists, somewhat serpentinous, dipping 70° and 60° northerly.
The slates dip 52° N. W. On the south side are the coarser conglomer-
ates, with porphyry pebbles, not distorted. The last outcrops on the
south side, before coming to the sienite area, consist of compact feld-
spars and siliceous slates, and a few diorites with dips like the others
named. The first sienitic or gneissic rocks are traversed by seams,
possible strata, dipping 35° N. E.

Until further exploration, I think the porphyries may be ranked as
Huronian, corresponding to the similar rocks of Lynn, Saugus, and else-
where in the Boston basin, while the slates and conglomerates agree
with the related rocks of Braintree containing the characteristic trilo-
bite Paradoxides.

Eruptive Rocks.

The most conspicuous of the eruptive rocks of the Coast district is the
sienite of Exeter ; the quartz is often absent, and it would then be styled
diorite. As both types of rock are common in this district, neither name
is appropriate for the whole series ; but for convenience I will follow the
Massachusetts report, and use the name of sienite for the rock generally.
My father points out the distinction clearly between these rocks in his
report, in the eastern part of the state, in the areas which are the perfect
analogues of our New Hampshire ones. The best known of them in
Massachusetts is that of Quincy, popularly called granite.

There are six areas of the Exeter sienite upon the south-east sheet.
The first extends from Alfred to Berwick, Me. This has been crossed
at Alfred, where a compact feldspar occupies the western border. Be-
tween Sanford and Lebanon are several exposures ; and Bonny Bigg hill
in North Berwick is of the same character. The second area, exclusively
in Maine, lies in York, South Berwick, and Eliot. Mt. Agamenticus
forms a part of it, and it is crossed on the road from York to South
Berwick. It extends down to Cape Neddock, also. The shape of this
area is like a crescent. The third and most important New Hampshire
area is on the line of the continuation of the first one mentioned, and we
cannot say with certainty they are not connected together. We have it
first in Rollinsford, whence it proceeds directly to Exeter and Brentwood,
where it passes beneath the lenticular drift hills that are so numerous

GEOLOGY OF THE COAST DISTRICT. 63 1

there. In Rollinsford the exposures lie to the south of the Portland
turnpike, appearing a short distance west of L. Stackpole's and along the
boundary road west of Fresh creek. In Dover there are a few outcrops
between Fresh creek and the main Cochecho river. The western limit
is at Sawyer's mills, and it is the prevailing rock west of Bellamy river
south of the Durham road. There is not much of the sienite in Mad-
bury, because of the narrowness of the town. Durham is chiefly under-
laid by this rock. It occupies ledges at the village, and at five places on
the direct road to Newmarket. West of the railroad it extends to school-
house No. 4. Following around the Great bay it is found to alternate
repeatedly with the Merrimack slate, as is the case all the way to Exeter
village. The slate is wider in the town of Newmarket than at any other
point between Dover and Exeter. The west border of the sienite is rep-
resented as even, perhaps through ignorance. All through Durham the
seams in the sienite dip north-westerly, as if they indicated the place of
strata. The more southern portion of this range displays a character-
istic feature of the exposures. They are very numerous, not much loose
material overspreads the ledges, and the soil is consequently barren.
There is also a profusion of boulders scattered upon the surface, whose
presence is usually a sure guide to the western limit of the area.

In Brentwood the western limit is reached at Marshall's corner, and it
lies next to gneiss. Seeing sienite blocks at Brentwood post-office (Craw-
ley's falls) used for piers of a bridge, I inquired for their source, and was
told they came from a quarry about a quarter of a mile to the south. I
have put in a small area to represent this statement, not feeling confident
that it can connect with the main mass to the east. The unusual amount
of surface deposits in Kingston and East Kingston obscure the ledges
along the proper line of the continuation of the sienite, yet we have hints
of it in Hampstead and Atkinson, and better evidence in Salem. There
is reason to believe in its existence also farther south-west in Dracut.

There may be a dioritic ledge on the east side of Exeter river, a mile
before coming to the north-east line ; but nearly all the east part of Exe-
ter is so covered by drift as to make a knowledge of the ledges impracti-
cable, save after a very thorough examination. The very point of the
town touches our fifth area of sienite, from Greenland to the south line
of Kensington. There are exposures of sienite along the Winnicut river.

632 STRATIGRAPHICAL GEOLOGY.

on the line between Greenland and Stratham, in the edges of Stratham
and North Hampton, and on the confines of North Hampton and Exeter,
west of J. L. Philbrook's. The west border of this point is composed of
felsite. In the west part of Hampton Falls are exposures by E. C. San-
born's, and next to a tributary of Taylor's river. At Sanborn's there has
been an opening for mining- purposes which reveals an intrusive diorite,
bunches of ankerite, plates of calcite, chlorite, crystals of smoky quartz,
narrow quartz seams, etc. The farthest exposure seen of sienite in this
range is near Miss Page's, in the south-cast part of Kensington. Its
further course is concealed by an abundance of till.

The last of these areas is that of Seabrook, which is the north end of
the Massachusetts mass. The western limit of it is where the Eastern
Railroad crosses the state line. It extends a mile and a half into the
township, and is then covered by drift. In the marshes opposite Bound
Rock the natural continuation of the sienite is taken by a granite. I
have examined a few ledges of sienite in Salisbury, Newburyport, and
Byfield, and have copied the delineation from the Massachusetts map.
Our observations develop nothing additional to what has been already
published by my father. There may be some further notice of these
rocks under the topic of Economic Geology.

The sienite of Mt. Pawtuckaway in Deerfield and Nottingham is repre-
sented as like that of the Belknap mountains. As it is midway between
the different areas, it is also intermediate in character between them.
Situated in the midst of gneiss, it does not afford evidence of age when
compared with the various mica schist groups. Like the more northern
variety of rock, it is accumulated in a mountain mass, and cannot easily
be esteemed a gneiss slightly altered.

The granites of our south-east sheet are of little moment, apart from
the numerous beds interstratified with mica schists, which have been
mentioned in their proper places. The granite of South Kingston and
in Andover, Mass., has been already alluded to. There is a very large
granitic area in North Berwick, Sanford, and Alfred, Me., which is more
like the Mt. Bet series of New Durham than anything else described in
New Hampshire. It may be that some of the sienitic area to the south
of Newburyport is to be regarded as granite.

The trap dykes are well represented in this district. Concerning one

GEOLOGY OF THE COAST DISTRICT. 633

on Pawtuckaway, Whitney says, in Jackson's report, — "On the lower
mountain there occurs a dyke of greenstone trap, wliich crosses its sum-
mit and divides it into two nearly equal parts. This dyke is singularly
columnar, and, on the face of a bare ledge, inclined about 45°, it assumes
the form of steps, fifteen or sixteen in number, each about nine inches in
height. They are known to the inhabitants as the 'Stairs.' It varies
from six to twelve inches, and was traced for a quarter of a mile." Final
report, page 30. Jackson speaks of other dykes on the sea-coast north
of Little Boar's Head, running in a north-east direction, and varying in
width from a few inches to ten feet.

One of the most interesting dykes seen near Portsmouth is one of
sienite twenty-five feet wide, near the powder magazine, two or three
miles out from the post-office. It has the course N. 50° E., and seems
to be conformable with the schist adjacent. The phenomena indicate
that this diorite, lithologically the same with much of the Exeter group,
was erupted after the deposition of the Merrimack group, probably dur-
ing the epoch of its elevation. I observed it for 200 or 300 feet in length.
Such facts suggest the origin of the Exeter rock subsequently to the
deposition of the Merrimack series.

There are several trap dykes on Frost's point. Rye. One of them is
fifteen feet wide, with many small, irregular branches. Loose specimens
near by seem like labradorite diorites. Several have been noted in Sea-
brook, as in the village and at the school-house to the south-east. A
short distance north of the village there is a beautiful porphyritic trap,
where the feldspar crystals are like kernels of rye, of light color, scat-
tered through the black base.

Little has been done in the study of the trappean rocks, as we have
been waiting to ascertain their proper mineralogical designations, which
will be given under the head of Lithology. Meanwhile we may call at-
tention to an interesting case of dykes crossing one another at Bald Head
in York. The first eruption was of a large, porphyritic trap dyke, with
the course N. 55° E.; the second kind is more compact and fine-grained,
running north-east, but irregularly ; the third series cuts across both the
others, and must therefore have been injected at a later epoch. The ma-
terial is a brown scoriaceous trap. These three kinds of rock occur in
our state, and belong to the same epochs of eruption with those in York.
VOL. iL 80

CHAPTER IX.

DESCRIPTION OF THE GENERAL SECTIONS.

•HE conduct of the geological survey of New Hampshire has been
based upon the careful measurement and delineation of fourteen
sections, crossing the state at regular intervals. These have been drawn
several times during the progress of the work, for the museum and for
study. Their final representation may be seen upon the geological map
in the atlas. Lines are drawn to indicate their positions through the
various townships, while the projections appear at the bottom of the sev-
eral sheets, so placed that the eye can readily connect the profiles and
geological coloring. These sections are drawn upon the same horizontal
and vertical scale. Our conclusions as to the age and equivalency of the
formations are based upon these delineations.

The museums of the New Hampshire College of Agriculture and the
Normal School contain the specimens procured for these sections, both
for New Hampshire and Vermont, those from the latter state having been
obtained at private expense by special trips taken for the purpose. The
shelves of the first-named museum show the perfected arrangement, and
it is to be hoped the same will be true of the collection at Plymouth.
At Culver hall a wall forty feet long is devoted to this set of specimens.
Fourteen shelves are arranged in order, one over another, from the floor
to the ceiling. Care is taken not to impede the view of the colored pro-
files between the shelves by braces or railing in the gallery, so that the
visitor may take in the whole structure at a single glance. The speci-

DESCRIPTION OF THE GENERAL SECTIONS. 635

mens from each section are placed in front of the drawings, each one
directly in front of its place on the profile, and corresponding numbers
enable one to identify the place of the 3,000 localities represented. This
wall of sections is therefore a truthful representation of nature. Every-
thing is in its proper place, not distorted by theoretical views; and one
can study the rocks nearly as well as in the field. The bringing together
of the specimens in geographical order will save years of travelling for
any who examine the collections.

The College of Agriculture caused to be prepared and exhibited at the
centennial exhibition at Philadelphia, in 1876, a delineation of thirteen
of these sections across both the states, on the horizontal scale of two
miles and a half to the inch. It would be very desirable to have this
drawing reproduced, one fourth the size of the original, for the atlas.
Much more detail could be given in such a sketch than is possible upon
the profiles placed at the base of the map sheets, and it would be possible
to illustrate the relations between the formations of the two states. This
is done to a small extent upon our sheets, as the profiles are made to
extend as far as the coloring, somewhat beyond the state limits. This
method of survey and illustration was first proposed by my father for the
Vermont survey, and was fully carried out for the report upon the geol-
ogy of that state. In the museum at Montpelier the specimens were
properly placed, but no sections were protracted for the spaces between
the shelves. It was supposed that the curator would have attended to
this business, as he aided in the collection of the specimens. Our
later collections and sections, relating alike to two states, possess more
than double the value of the first, since they cover twice as much area,
and exhibit the results of ten years of study. Repeated visits to the
localities and a comparison of conclusions enable us to locate overturns
and faults, very essential to the proper understanding of the positions of
the rocks, but which cannot be discovered without great effort. It is not
claimed that the representations are yet beyond the possibility of im-
provement.

Our limited space will prevent us from giving detailed descriptions of
all these sections. Those desiring information beyond that of the report
will find it at the museum. I will notice the sections in order from south
to north.

6^6 STRATIGRAPHICAL GEOLOGY.

Section I.

The first section follows the most southern tier of towns in the state,
and is made to extend to the Atlantic ocean, in the south part of Ipswich
in Massachusetts. Our collection of specimens commenced at Lawrence.
The section delineated is about ninety-six miles in length, ten miles dis-
tance being in Vermont, beyond Connecticut river.

At the east end next the ocean is a broad stretch of salt marsh. There
is a broad band of sienite next, followed by hornblende schist. In George-
town is the hornblende schist range, possibly of Huronian age. Boxford
and North Andover exhibit the gneiss, called Laurentian by some, and
much like the Lake group of New Hampshire. After this, in the Merri-
mack valley through Lawrence, Methuen, and Dracut, we find the Mer-
rimack group dipping usually at a high angle to the north-west. The
gneiss east of Lawrence dips easterly; and there may follow, first, a syn-
clinal before reaching Essex street, Lawrence, then an anticlinal, the west
end having a smaller dip {see Fig. 109). The junction of this Merrimack
quartzite with the Pelham gneiss is not seen ; but the dips in Dracut and
Pelham indicate that the pressure has been exerted so as to fold the anti-
clinal beneath the westerly-dipping gneiss at N. Hobbs's. The gneisses
in the extreme east and west parts of Pelham dip towards each other,
though the presence of a porphyritic gneiss at J. Gage's, west of the vil-
lage, suggests a double synclinal resting upon an older rock between.
There are materials for two axes in Hudson, the western border of the
gneiss dipping 50° N. 30° W. at a turning-shop.

Next there is the broad valley of mica schist of the Nashua valley,
referred to the Rockingham series, and making a double basin with a
narrow range of gneiss in the middle. This extends into the edge of
Brookline. Proctor hill furnishes examples in the western part of the
micaceous area of the interesting feldspathic or granitic beds, such as
have been noticed farther to the north-east. A range of Merrimack slate
seems to belong to the middle of the band, in the west part of Nashua.
The Lake gneiss following displays a prominent anticlinal along the west
line of Brookline, with a probable synclinal to the cast of the village. In
Mason there is so much divergence between the dips east and west of
the railroad as to suggest the presence of a folded westerly inclined anti-

DESCRIPTION OF THE GENERAL SECTIONS. ^l*]

clinal. On reaching Greenville we are introduced to a considerable
breadth of the ferruginous and other mica schists most, likely connected
with the Montalban series. The westerly dips prevail entirely through
New Ipswich, but we have shown in Fig. 94 a basin of mica schist over-
lying the older rocks, reaching from the village to the east base of Barrett
mountain. It is likely an anticlinal is present in Barrett mountain, which
is the mountain ridge between the Merrimack and Connecticut valley
depressions. Between the east line of Rindge and Peasley pond are two,
perhaps three, axes in the ferruginous group of the Montalban. In Fitz-
william there rises to the surface a little porphyritic gneiss, with the pecu-
liar granite of the region upon both flanks. There is a difference of opin-
ion whether the latter rock is a true granite or gneiss, whose planes of
stratification are usually obliterated. There are also two appearances of
the Bethlehem series in Fitzwilliam. In the west part of the town the
Montalban rocks dip 75° westerly, making a sharp synclinal with the same
strata in the east part of Richmond ; and there is another anticlinal be-
fore reaching the village. From this village through the rest of the town
and the principal part of Winchester the gneiss is thought to belong to
the Bethlehem series, with quite variable dips. There would be the basin
structure before reaching Muddy brook, perhaps a second synclinal in
the valley of that stream, though this is not clear, and a very distinct
anticlinal between Muddy brook and the tributaries of Perchog river.
This gneiss distinctly and unconformably underlies the Coos quartzites,
the point of contact being visible. This comparatively modern group
furnishes three ranges of quartzites before coming to Connecticut river,
which are supposed to constitute one band repeated, and to underlie the
mica schists, the latter assuming the basin shape, and carrying notable
quantities of indigenous granite.

The quartzite crops out on the west side of the river at South Vernon.
As the next seven miles have been described already with much detail
(p. 437, Fig. 71), it will be unnecessary to repeat the observations here.
To the west of the Cambrian are easterly-dipping slates, at Fall river.
Guilford will be found represented in a basin of the Calciferous mica
schist, followed by an anticlinal ridge of hornblende schist, supposed to
be Huronian. The sheet ends with the repetition of the calcareous
rocks on the west side of the hornblende.

638 STRATIGRAPHICAL GEOLOGY.

Section II.

The second section commences at Seabrook, at the south-east corner
of the state, and passes through the towns of South Hampton, Newton,
Kingston, Hampstead, Dcrry, Londonderry, Litchfield, Merrimack, Am-
herst, Milford, Wilton, Temple, Peterborough, Jaff rey, Marlborough, Swan-
zey, and Chesterfield, a distance of ninety miles. About five miles of
Vermont are appended, in the town of Brattleboro'.

The very east end of the section consists of the northern termination
of the Newburyport range of sienitic rocks, overlaid by thick deposits of
sand and marine mud. There are exposures of a granitic rock traversed
by segregated veins in the marshes, which may underlie the sienite.
There is about a mile width of Merrimack schists to the west of the
crystalline masses, extending a short distance beyond Seabrook village,
which are much disturbed by miscellaneous trap dykes. They seem to
stand very nearly on edge. One of the large feldspathic masses common
in this group is found a short distance west of the village. From there
no ledges can be found for eight miles, because they are concealed by
the enormous development of lenticular drift hills. The rock is thought
to be the same with that in Seabrook. Through Newton and Plaistow
the dips are north-westerly, and of material suggestive of the Rocking-
ham group, save the first ledge in South Hampton, The dip changes so
as to furnish a synclinal in Hampstead, and an inverted anticlinal next
the ancient range of gneiss extending from Hampstead village to the
Nashua & Rochester Railroad in Derry. In this are some minor undu-
lations, but the general inclination is westerly, to underlie the broad mica
schist belt in Derry, Londonderry, and Litchfield. The structure of this
last is usually synclinal, the axial line running through the east part of
Londonderry. In the west part of Derry are argillaceous schists, the
highest part of the series possibly belonging to the Merrimack division.
Extensive feldspathic or granitic beds prevail in the outer parts of this
basin upon both sides. Litchfield shows no rocks, being covered by
sand. The next group is the ancient twisted gneiss of the Manchester
range. At Souhegan village are outcrops of a very coarse mica schist,
seemingly the upper layer of the formation, and repeated on the other
side of the fold. This last axis is a very marked one, the ridge line con-

DESCRIPTION OF THE GENERAL SECTIONS. 639

necting with the antichnal noticed on the first section between Brookline
and Mason. In Milford is found a large development of granite, one of the
ovoid masses occupying the stratigraphical horizon of the rock quarried
in the north part of Manchester. There is no change in the position as
far west as the formation occurs, into the eastern edge of Wilton. Not
far from its western border there occurs one of the famous quartz bands
dipping north-westerly, and reappearing in the eastern part of Temple.
Between them the rock is mostly a long, narrow strip of Rockingham
mica schist, with several small, subordinate folds, the western part hav-
ing a less inclination than the eastern. The quartz of Temple lies in a
narrow band of Lake gneiss, followed on the west by the mountain mass
of mica schist in Pack Monadnock, dipping west. In Peterborough the
western edge of the mica schist makes a synclinal trough; and another
gneiss area shows itself, with two or more folds in it. In the west part
of the town and in Dublin the porphyritic gneiss succeeds. This forma-
tion occurs along two different lines in Jaffrey, each believed to extend
beneath both the Peterborough gneiss and the ferruginous Montalban
rocks of south-eastern Cheshire. Mt. Monadnock follows next. This is
believed to belong to the Kearsarge andalusite group, and to overlie un-
conformably the Montalban rocks. In structure it seems to be a double
synclinal, and it rests upon a basin-shaped arrangement of strata. The
Montalban strata on the west side in Marlborough dip easterly generally,
and contain patches of Concord granite. In Swanzey there is a broad
Bethlehem band, with nearly uniform high easterly dips. It overlies the
Winchester and Chesterfield anticlinal porphyritic gneiss area. A little
Montalban gneiss skirts this on the west, followed by the Coos group,
which exhibits the common structure of two basins side by side. In the
Connecticut valley it is followed by an older ridge of Cambrian slates.
West of the slate the structure is exactly the same with that west of Fall
river on Section I, with Calciferous mica schist on both sides of the
hornblende schist anticlinal. Denudation has cut through this horn-
blende in West Brattleboro', and displays the underlying arched gneiss,
which may correspond either with the Bethlehem or Lake division of
New Hampshire gneiss. I once calculated the amount of erosion from
this arch, finding that 950 feet of gneiss and 2,640 of hornblende were
required to fill out the gap.

640 STRATIGRAPHICAL GEOLOGY.

Section III.

Section III extends from Newcastle and Portsmouth to Walpole, as
specially measured, a distance of seventy-five miles, but some additional
facts are known for a little of Kittery, Me., and Westminster, Vt. From
Kittery through to Newmarket Junction the rocks are referred to the
Merrimack group, composed of quartzites, siliceous mica schists, argilla-
ceous rocks, with a few feldspathic beds resembling granite, consisting of
arenaceous beds metamoriDhosed in place. From Kittery through to
Stratham the predominant dip is westerly, corresponding to the easterly
dips on the west side of Great bay in Newmarket. Along this section the
water of the Great bay seems to occupy a natural basin. In the eastern
section of the basin we find several minor axes, as in the north part of
Newcastle, among the houses in Portsmouth, etc. More will be discov-
ered after careful scrutiny. Next to this modern group comes the Exeter
sienite, lying in Newmarket and the east part of Epping. It is followed
by essentially the same micaceous and quartzitic formation, though de-
scribed in the report under the designation of Rockingham. There is a
well-marked basin just east of Epping village, and an equally distinct
anticlinal in the west part of the town. This has been noted as the great
line of division between the eastern portion, perhaps belonging to the
Merrimack group, and the Rockingham and Huronian beds to the west
in Raymond. The anticlinal is made by the presence of the Hamp-
stead gneiss range, choosing for itself a partly subterranean pathway to
join the ancient gneiss in Nottingham, but coming to the surface in West
Epping. The schists to the west of this gneiss constitute a synclinal,
closely pressed in the east part of Raymond, and containing a very marked
band of white quartz just east of the depot. On the west side of the vil-
lage, as far as to Jones's pond, the ledges consist mostly of supposed
Huronian hydro-mica schist, with some dolomites, suggestive of the Lisbon
group in the Ammonoosuc district. There is next a considerable width
of the Manchester range of gneiss, remarkably twisted, very granitic, and
showing in the central part of Candia the master anticlinal noticed upon
Sections i and 1 1, in Mason and Amherst. East of it is the inverted
anticlinal in the west part of Raymond, and a synclinal in the east part of
Candia. The Manchester granite is not conspicuous in its proper place

DESCRIPTION OF THE GENERAL SECTIONS. 64I

on the line of strike, but an additional band shows itself, the continuation
of the Hooksett area, in and on the west side of the Merrimack river in
the south part of the town. On Campbell's hill is the southern range of
quartz, not far from its eastern termination. Through Hooksett the rocks
dip westerly to just beyond the western band of quartz, where there is
evidence of a short synclinal, which ought to cause a repetition of the
quartz if it be a genuine basin. There would seem to be an anticlinal
following, between the south end of Bow and Dunbarton. These rocks
all belong to the Lake gneiss, but that which follows in Dunbarton is
Montalban, and strangely enough it presents the anticlinal structure at
Kimball's pond. On Dunbarton hill the Lake gneiss reappears with
west dips. Hence this Montalban development either rests unconform-
ably upon the Lake gneiss, or else there is an inversion equal to that
described as characterizing the porphyritic gneiss (p. 529). In the east
part of Weare occurs one of these porphyritic gneiss areas, with westerly
dips. This has Lake gneiss upon both sides, all three bands similarly
inclined, and hence inversion must be invoked to explain the phenomena.
In the middle of Weare is the westerly-dipping mass of Mt. WiUiam, con-
sisting of Rockingham mica schist, and resting upon the Lake gneiss,
which is more characteristically developed in this town than is usual
away from its typical region. We have evidence of two foldings in the
west part of this area, the last dipping westerly, to come up again in the
narrow range to the east of Deering village. The rock between the
Merrimack ferruginous slates, partly in Weare and partly in Deering,
and so far as seen along the section, dips uniformly to the north-west.
West of the Deering gneiss belt the ferruginous slates reappear, with a
very distinct basin shape, resting upon still another gneiss belt along the
Contoocook river. The two gneisses are also supposed to dip towards
each other beneath the ferruginous formations.

In the Contoocook gneiss, on the west side of the river in Antrim, is
an outher of Montalban dipping with the former, because apparently
caught in it and forced to conform to it. On reaching the valley of the
northern branch the porphyritic gneiss of the main central range is met
with, dipping easterly underneath the Lake gneiss. Very soon the dip
is reversed, and in the west part of the town there is a well-marked syn-
clinal in it. The easterly dip is then continuous to Stoddard village,
VOL. II. 80

642 STRATIGRAPHICAL GEOLOGY.

where it is underlaid by inverted gneisses of the Montalban series. In
Stoddard this assumes the anticlinal form, followed by a synclinal in the
east part of Gilsum. This Montalban area terminates obtusely in the
north part of Stoddard. The west part of Gilsum is occupied by east-
erly-dipping strata of Lake gneiss. In the north part of Surry we cross
the narrow range of fibrolite schist carrying the very coarse granite
veins. This rock dips westerly at a high angle, and probably rests un-
conformably upon the Lake gneiss to the east in Gilsum, and upon the
Bethlehem group in the west part of Surry, the latter dipping easterly,
being almost vertical. Walpole is entirely composed of the Coos rocks.
The high hill west of the Ashuelot river exhibits mica schists, carrying
granitic beds with small westerly dips, running underneath the quartzites
along Fisher brook. Farther to the west the dips are higher, indicating
an antichnal, and hence the quartzite is older than the mica schists, but
made to assume the inverted attitude by the terrible crowding from the
east by the Gilsum and Surry gneisses. Just east of Walpole village are
ledges of argillaceous schists, dipping only 10° N. W. If these belong
to the Coos group, as seems probable, they would correspond to the
schist in the east part of the town, and are in their normal position.

We have now reached the modified drift of the Connecticut valley,
which conceals the ledges for a considerable distance. In Westminster
we find the Cambrian clay slates, nearly vertical and inclined towards
the Walpole rocks. The few miles west of the river on this line have not
been directly traversed. The occurrence first of the calcareous rocks
west of the slates, and then of a narrow band of hornblende schist, over-
lying a large gneiss area, is well established by observations upon both
sides of the section line.

Section IV.

Section IV properly commences at Great Falls, passing through Som-
ersworth, Rochester, Barrington, Strafford, Northwood, Epsom, Chiches-
ter, the north part of Concord, Hopkinton, edge of Warner, Bradford,
Washington, Lempster, Acworth, and Charlestown to Connecticut river,
a distance of eighty miles.

The rocks east of it in Maine for ten miles are believed to consist
exclusively of the Merrimack mica schist. Their stratigraphical position

DESCRIPTION OF THE GENERAL SECTIONS. 643

has not yet been determined. The same group extends through Somers-
worth and the south part of Rochester, and there is an antichnal in it.
The enormous sand plain of Rochester and Gonic obscures the under-
lying rock ; but in Barrington is a considerable Rockingham schist, with
the uprising of an ancient gneiss in the south part of the town. In the
west part of Barrington the Rockingham rock reappears, followed by the
gneiss of the Bow lake and Northwood region, in which there is an anti-
clinal, and the westerly dips prevail through Northwood, underlying the
next Rockingham band through Epsom. This shows us the basin struct-
ure, resting upon Lake gneiss in Northwood on the east, and the Montal-
ban in Chichester on the west. In Chichester and Pembroke the dip is
north-westerly, so that this White Mountain series is anticlinal in form.
Next the broad sand plains of Concord cover most of the ledges. The
section passes across the north end of the oval granite area of Concord,
and the smaller patch north-west from Pine hill. The same north-west
dip prevails through this formation in the north part of Concord, includ-
ing the interesting band of white quartz at West Concord. This Montal-
ban ridge is not crossed at right angles by the section, as it runs between
north-east and east. Before reaching the west line of Concord we dis-
cover the later ferruginous slates, with dips at such diverging angles as
to suggest the presence of one or more foldings. At Contoocookville
another Concord granite area presents itself, following an outcrop of the
ancient porphyritic gneiss on the hill south from Tyler's station. The
dips of this and the accompanying ferruginous schists are easterly, all
overturned. West of the Contoocook granite is another part of the
ferruginous group, apparently synclinal in aspect, with soapstone in the
edge of Warner. The section nearly crosses the Montalban of the south-
east part of Warner, carrying the quartz and limestone, and evidently a
repetition of the West Concord exposures. The ferruginous slates to the
west of this Montalban upheaval dip westerly, folding over the underlying
formation. Next follows a long breadth of porphyritic gneiss from Hen-
niker to Washington. This consists of a series of folds, an anticlinal in
Henniker, followed by a synclinal to accommodate the hard schists oc-
curring along Warner or Harriman brook; a second anticlinal east of
Day pond, and the succeeding basin holding the Lake gneiss area about
Bradford pond ; another repetition in the same order in the south part of

644 STRATIGRAPHICAL GEOLOGY.

Bradford, where is another patch of mica schist. Other axes occur just
to the north of Murdo hill, East Washington, and perhaps at Washington
village, the western border of the gneiss. Part of this section has been
given in Fig. 85. The west part of Washington is occupied by the
usual Lake gneiss of the country west of the porphyritic dividing ridge.
The strata everywhere stand nearly vertical. Near its western border the
porphyritic gneiss reappears in what has been called the Marlow range.
West is the Lempster mountain range of mica schist, carrying the very
coarse granite veins from which mica is obtained in merchantable quan-
tity. The dips are all easterly.

The greater part of Lempster and the east of Acworth belong to the
Lake or common gneiss, as described in Chapter V. Many dips are south-
erly at small angles, so that one or more folded axes may be made out.
The western border of the ancient gneisses is reached near Lynn in Ac-
worth ; after which Coos mica schists and quartzites prevail to the Con-
necticut river through Acworth and Charlestown. These rocks exhibit
several foldings; and extensive denudation is indicated by the isolated
patches of quartzite on several hills. There is evidence in Acworth and
Charlestown of conspicuous faults, insomuch that any present theory of
structure must be received with large allowance. Starting from the east
border of the mica schist, near the village of Acworth, there is a strongly
marked anticlinal. On the hill by J. Grant's (p. 416) the quartzite is said
to lie horizontally. The southern extension of the range at Z. Slader's
acts like a shallow synclinal. At Prospect hill in Charlestown is a high
south-east dip; vertical strata on the high land between Page and Oak
hills, so that a synclinal is needed to connect the Prospect with the Ac-
worth schists; four axes before coming to the Oak Hill quartzite range,
near Charlestown village; and an inverted synclinal in Calciferous mica
schist west of the quartzite range. One can hardly help suspecting the
recent age of this quartzite from the descriptions given of them in Chap-
ter IV. They are repeated in Skitchawaug mountain, in Springfield, Vt.,
making a distinct synclinal axis (p. 412). There is now a new matter of
interest on the Vermont side of the river, since a band of Huronian two
miles wide has made its appearance in nearly vertical strata. West of
it is the continuation of the Calciferous mica schist group, probably in
synclinal attitude, and beyond is the ancient gneiss of Chester, whose

DESCRIPTION OF THE GENERAL SECTIONS. 645

structure will appear to better advantage farther north, because it has
been studied there. The clay slate of the lower sections seems to be
wanting on Section IV, unless it be buried beneath the alluvium.

Section V.

We have satisfactory data for the delineation of the whole of this
section, from the extreme eastern limits in Alfred, Me., to Reading, Vt.,
a distance of ninety-five miles. It passes through Alfred, Sanford, Shap-
leigh, and Acton, Me.; Milton, Middleton, New Durham, Alton, Gilman-
ton, Belmont, Tilton, Franklin, Andover, Wilmot, Springfield, Grantham,
edge of Croydon, and Cornish, N. H.; Windsor, including Mt. Ascutney,
West Windsor, and Reading, Vt.

The Maine portion of this section has been illustrated sufficiently well
in Fig. 108, PI. XXV, and the accompanying description. The first rock
in our state is the Rockingham group, showing several undulations in the
first two towns, usually of little general consequence. The presence of
the andalusite schist on the east of a prominent anticlinal in Acton sug-
gests the possibility of finding the same repeated in the east part of Mil-
ton. In Middleton may be seen Montalban rocks underlying the mica
schists of Milton, imperfectly developed on account of the abundance of
drift scattered everywhere as a thin covering over the ledges. The axes
through to Lake Winnipiseogee are noted upon page 603. On the west
side of Alton bay is a large ledge of sienite ; and near the travelled road
no other ledge has been noticed, except one of mica schist on the sum-
mit, dipping 70° N. W. This is the northern end of a large area of this
description, repeated on reaching Gilmanton. Between Pine mountain
and Place's pond are areas of porphyritic gneiss, with vertical strata, and
sienite. The Rockingham group through Gilmanton and Belmont is char-
acterized by the presence of numerous minor undulations, six or more in
number. Among them is a synclinal constituting the ridge of Grant and
Lamprey mountains ; and the place of an inverted anticlinal west of Bel-
mont village, occasioned by the underlying gneiss. Another well-marked
gneiss area appears in Northfield. At Tilton the dip changes abruptly,
since the rock is different, most likely Montalban, the beginning of the
Merrimack Valley area of this formation. Near the west line of Franklin
appears the anticlinal in it, caused by the extension northward of the

646 STRATIGRAPHICAL GEOLOGY.

Lake gneiss of Salisbury. The Montalban may extend a little beyond
Horseshoe pond ; after which are the close complicated axes of the Kear-
sarge group, illustrated in Fig. 103. Past Andover succeeds the great
central ridge of porphyritic gneiss in Wilmot, with two closely pressed
folds. Across Springfield and Grantham is the widest part of the Lake
gneiss development west of the central ridge to be found anywhere in
the state. There seems to have been an extensive uprising of the earth-
mass in this region, not sufficient to bring up the porphyritic rock, but
enough to prevent the deposition of the micaceous group, unless the
elevation took place after its accumulation, and its exposure to atmos-
pheric agencies has led to its removal by denudation. Portions of this
gneiss are somewhat porphyritic. There must be a synclinal between
Col. Sanborn hill and Station pond, both sides dipping easterly, the east
one the most. Stocker pond is about the place for the anticlinal. There
is a basin for the valley of Croydon branch in Grantham, on the west side
of which is a long stretch of white quartz. Farther west we come to an
area of Bethlehem gneiss, extending into Croydon, and possibly reaching
to the west border of the gneiss, though not so represented upon the map.
A synclinal to the east and an anticlinal on the west show us the struct-
ure of the area. Protogene gneiss characterizes the centre, and a por-
phyritic variety the west side of this development. The last dip is quite
moderate, only 15° W., and it is covered by the Coos rock of Croydon
mountain. The first met with is quartzite, dipping 75° N, W., and soon
afterwards the dip is in the opposite direction, so that the first range of
quartzite is a closely pressed basin. On the west slope of Croydon moun-
tain the mica schists with staurolite overlie the Calciferous schists, proba-
bly by inversion. The attitude of the rocks through Cornish is expressed
in Fig. 62, page 397. This is the broadest area of this formation in the
state, and is evidently characteristic of the group. The eastern portion
is clearly monoclinal, and here is inverted. Two or three faults develop
subordinate axes in the west part of the town, the first between two Hu-
ronian bunches, the second occurring on the east bank of the Connecti-
cut, a short distance above the bridge. These Huronian bands are the
narrow representatives of hornblende and hydro-mica schists developed
much more extensively farther north. Crossing into Windsor the section
passes over Mt. Ascutney, which is a high mountain composed of igneous

DESCRIPTION OF THE GENERAL SECTIONS. 647

material, partly of Eozoic age and partly exuded since the deposition of
the Calciferous. The igneous material occupies an east and west chasm
in the limestone, and has altered the rock in contact with it. The mate-
rial is sienitic and felsitic, much like the Chocorua series. On reaching
Little Ascutney we find partly the same eruptive rocks, breccias, and
gneisses, the latter making an anticlinal with the eastern part of the
range found at the west ends of the first five sections. I have traversed
this line across the state of Vermont, and find the normal structure of
this gneiss range in West Windsor and Reading to be anticlinal. The
gneiss is like that of Grantham and Newport in New Hampshire. A
depression in it in the west part of Reading carries a small synclinal of
the Calciferous mica schist, and the gneiss most likely exists as a syncli-
nal underneath it. This gneiss does not crop out again on the line of
strike until we reach Section X.

Section VL

In proceeding northerly the width of the sections in New Hampshire
diminishes, the present one being seventy-one miles long, from Effingham
border to the Ledyard bridge at Hanover. The coloring of the map and
section extends ten miles farther into Vermont. The eastern portion in
Maine has not been explored particularly, though confidently believed to
belong to the Montalban series, and so described heretofore. The ridge
of Lake gneiss extends into Parsonsfield from Wakefield, thus separating
the Montalban into two parts. The dip has been represented as uni-
formly monoclinal to the east in this section of Maine. Green mountain
consists of granite, which has come up through an east and west fissure
in the schists, like Ascutney, and accumulated in amount sufficient to
build up a considerable eminence. Our observations exhibit an anticlinal
to the south of the mountain, the first dips being to the south-east. This
has been thought to be naturally connected with the formation of the
fissure through which this granite has been erupted. The Montalban
schists through Effingham and Ossipee are like those of the typical re-
gion, tender, friable, imperfect, and often ferruginous gneisses. In the
town of Ossipee there is a closely-pressed synclinal showing this forma-
tion to overlie the Lake gneiss of the Winnipiseogee basin. This more
ancient gneiss shows itself in vertical exposures about Dan Hole pond,

648 STRATIGRAPHICAL GEOLOGY.

overlaid both to the north and south by eruptive rocks, the Conway
granite on the former side, and porphyry on the latter. In passing near
Melvin peak the porphyry is found to succeed the gneiss of "Canaan,"
and to occupy nearly the whole of this eruptive area of Ossipee. At the
Ossipee falls, on the west side, the Albany granite is found beneath the
porphyry in a thin strip, resting like a blanket upon the upturned edges
of the Lake gneiss. To the south of the mountain mass the dividing line
between the Montalban and Lake groups runs through Tuftonborough
corner. Between Ossipee falls and Center Harbor the section passes
through the typical region of Lake gneiss, and exhibits three important
flexures. West of the Center Harbor landing we find porphyritic gneiss,
with westerly dips. This has been already shown to be doubled like
the barb of a fish-hook ; and the range repeats itself, with fan-shaped
structure, in New Hampton. The Lake gneiss between has been forced
into a monoclinal attitude, with a small anticlinal just at its west border
north of White Oak pond in Holderness. After passing the porphyritic
gneiss, the Montalban succeeds through Bridgewater and Hebron, exhib-
iting no less than five foldings. The anticlinal of Peaked hill in Bridge-
water seems to be quite an important one. Fig. 82 covers nearly the
same ground with this section between the Ashland and Groton bands
of porphyritic gneiss. Another, on a parallel line to the south. Fig. 95
(p. 567), shows five foldings in the Montalban. North of Hebron village
we have the mica-bearing rock in its largest development. Groton, along
the section line, mainly consists of porphyritic gneiss, being the northern
end of the great central range, and exhibited only because Cockermouth
brook has cut down through the superincumbent formations. The west-
ern border of the porphyritic gneiss is thought to be overlaid unconform-
ably by the mica schist, the same with that in the north part of Hebron,
and is disposed as a double basin. This is underlaid on the west side
by the Lake gneiss, in a closely-pressed anticlinal dipping easterly. It
is supposed to underlie by inversion the porphyritic gneiss in the axis
between the micaceous basins just mentioned.

Two bands of hornblende schist occur in Canaan, on the sides of a
synclinal mass of fine-grained Bethlehem gneiss. To the west of this
hornblende, cropping out near Goose pond, is an anticlinal mass of the
coarser Bethlehem gneiss, occupying all the space between the finer-

DESCRIPTION OF THE GENERAL SECTIONS. 649

grained variety and the Moose Mountain Coos development. The west-
ern part of it is coarsely porphyritic.

In Hanover we find on Moose mountain a conspicuous and persistent
range of quartzite, standing nearly vertical, and not exhibiting, so far as
understood, any folding. It is overlaid by staurolite mica schists, dipping
westerly, and, it is supposed, beneath clay slates of the later part of the
Coos age. These last are disposed in the double basin attitude, supposing
that the western part, consisting of purely vertical strata, is a fold closely
crowded. They bear some resemblance, however, to the Cambrian slates
of the Connecticut valley (p. 394). The segment of micaceous schist fol-
lowing belongs to the upper part of the Bethlehem group; and I have
sometimes represented it as separated by a fault from the slates on the
east, and the typical Bethlehem area on the west. They have an east-
erly dip throughout. West of Mill village follows next the Hanover area
of Bethlehem gneiss of the typical variety, a coarse protogene gneiss.
The structure of this has been studied more than that of some regions,
because of its situation near the head-quarters of the survey; and we
are well satisfied it is an inverted anticlinal dipping westerly. A band
of white quartz traverses it like those so often referred to in other for-
mations. On the west side of it is a repetition of the Moose Mountain
quartzite and mica schist, less in their thickness but identical in composi-
tion and age. Their dip is westerly, the same as that of their analogues.
On the college grounds the hornblende schist, inverted over the Coos
slates, makes its appearance, dipping to the west. It is about a mile wide,
and may be seen in close contact with the Lisbon group of the Huronian
in Norwich. A careful analysis of this formation in Norwich (p. 363)
shows the probable existence in it of five flexures. I doubt not similar
reduplications can be found in every town of the state, if explored as
thoroughly as these conveniently-situated ledges near our head-quarters
have been. Next occur the Cambrian clay slates, monoclinal, and in their
natural place between the Huronian and Calciferous groups. The latter
exhibits through Hartford a synclinal structure, and on the west side
succeed micaceous quartzites dipping easterly beneath them. The latter
I have referred to the Coos group, believing the calcareous strata usually
overlie them. The area occupied by similar non-calcareous schists is
quite large in Vermont, and I have not yet been able to satisfy myself
VOL. II. 82

650 STRATIGRAPHICAL GEOLOGY.

thoroughly that they are properly classified. In order to explain their
place in West Hartford, one of two alternatives must be taken : either
these micaceous quartzites are the equivalent of the clay slates, since
the two formations dip tov\^ards each other beneath the limestones, or
there must be tv^o faults, one on each side of the quartzites, to enable
them to lie between two calcareous areas. The larger fault would in
this case stretch along the valley of White river, perhaps running up to
the neighborhood of Copperas hill. After leaving West Hartford the
limestones reappear, more thoroughly calcareous than before, and dip-
ping at a much smaller angle easterly, or in the same direction. If this
rock be followed through to Barnard, we find three well marked folds
in it, with a supposed fault before coming to the clay slate group again.

Section VII.

This was not one of the original sections marked out. It was found
desirable to represent the rocks along its route, and therefore observa-
tions were taken for it from Freedom, just touching the north base of the
Ossipee mountains, passing thence north of west to Sandwich notch.
Our specimens and observations have been taken along this line. Reflec-
tion shows that this is an unfortunate route, because quite crooked and
terminating too near Section VI. I have therefore made use of whatever
observations could be had along a line farther north, and will draw the
profile to fit the new locality, saying what seems to be true of it, hoping
to be able to travel over the ground directly along the line before the
representation has been finally engraved and colored. Should there be
any discrepancy between the description and the protraction, the reader
may know the latter to have been obtained from information provided
subsequently to the preparation of the text.

As thus altered, Section VII commences near Sebago post-office, in
Maine, reaches New Hampshire in Eaton, passing then through Madison,
Tamworth, Sandwich, Campton, Ellsworth, Wentworth, and Orford, and
in Vermont through the limits of Fairlee, Thetford, and Strafford. The
total distance through New Hampshire is fifty-nine miles ; from the
extreme point in Maine to the end in Vermont, eighty-seven miles.
On this line we first touch the outer edge of the White Mountains.

From Sebago across to Chocorua pond the rocks are exclusively Mont-

DESCRIPTION OF THE GENERAL SECTIONS. 65 1

alban. It is believed the great anticlinal, causing the rocks to dip in
opposite directions, while those on each side are mostly inverted, takes
its course nearly along the state line, so that all the Maine ledges on this
section have the south-east, and those in Eaton, Madison, and Tamvvorth
the north-west, dip of this arrangement. On reaching the north part of
Tamworth the Chocorua group of granitic rocks is met with. The section
crosses the southern extension of these eruptive masses, protracted south-
erly from Mt. Chocorua. The view of the latter mountain in our colored
heliotype certainly suggests the presence of other groups besides this on
the north side of the pond, but I have no positive knowledge respecting
their possible occurrence. A range of Montalban succeeds, extending to
Weed's Mills, and thought to consist of a folded synclinal. The occur-
rence of Lake gneiss a little south of the section in Sandwich and con-
verging to a point, suggests its presence across the line of description
underground, thus producing an anticlinal division of the Montalban,
which may not necessarily show itself at the surface. Farther south the
gneiss shows three folds. In order to reach the Notch from Weed's Mills,
one may pass north of Guinea hill and over the Black mountain spur of
Sandwich Dome. We find here gneiss dipping north-west and north.
The west part of the town is occupied by a range of porphyritic gneiss.
Next is a synclinal of Montalban holding a large dyke of Albany granite,
and showing a slight recurrence of the porphyritic gneiss in the east part
of Campton, and quite fully in the Pemigewasset river. Between these
two ancient ranges we must conclude the monoclinal Montalban strata to
consist of an inverted synclinal. A similar easterly dip prevails west of
the Pemigewasset, before coming to the porphyritic gneiss of Ellsworth.
The latter consists of two folds, the most western occupying the slope of
Carr's mountain. In a basin near Ellsworth pond is a considerable band
of andalusite mica schist, either Montalban or later, perhaps connecting
related rocks in Rumney with others in Woodstock. On the summit and
west side of Carr's mountain the andalusite mica range occurs contiguous
to the porphyritic gneiss and dipping towards it. In Wentworth the
Lake gneiss has a full development, having a monoclinal east dip before
coming to Baker's river, and showing an anticlinal on the west side. An
isolated band of quartzite indicates an underlying gneiss basin in the
west part of the town. In Orford the prominent quartzite range of Mt.

652 STRATIGRAPHICAL GEOLOGY.

Cuba rests upon Bethlehem gneiss, the first indicating a basin form, and
there being a well marked anticlinal between the two quartzites. Fig. 5 1
shows facts of stratigraphy in a section from Mt. Cuba to Orford street,
a little to the north of our route of examination. The Bethlehem range
is well marked west of the Cuba ridge. It contains an important bed of
limestone, and exhibits one or two folds, the undulations being less marked
here than farther north, because more compressed. West of Bass hill the
particular features of this section as far as Connecticut river are shown
in Fig. 52. These are, first, two foldings in Coos schists; second, an
underlying patch of Huronian with soapstone at Orfordville ; third, mono-
clinal Coos schists containing narrow bands of granite and hornblende
schist. Underneath the meadows of Orford and Fairlee there must be a
considerable amount of Huronian to connect the known outcrops of that
formation in North Thetford and Fairlee. The first rock visible to the
west of the modified drift is clay slate, near by the north end of the Hart-
ford and Thetford band. Next is a broad band of the Coos micaceous
quartzites, reaching as far west as Podunk pond in Strafford. Next the
eastern border of this group, in the extreme north part of Thetford, two
folds are obvious, while in Fairlee a synclinal band is indicated by the
divergence in the dips, 15° and 60° N. E. There is a new strike in the
strata about the Ely copper mine in Vershire, and also at a similar vein
east of Strafford. On comparing other copper veins with these, we find
a suggestion that the copper is either in or near an older hornblende
range, and hence we may be guided in determining the nature of the
foldings in the cupriferous region. West of Podunk pond, in Strafford,
the change in dip and rock is so abrupt as to suggest the presence of a
fault. The hill east of the Centre village appears like an inverted syncli-
nal of the mixed mica schists and limestones lying upon a hornblende
band. The characteristic limestones with easterly dips occupy the valley
of the Pompanoosuc in the middle of the town, and make an anticlinal
in the hill west.

Section VIII.

Section VIII may be said to begin at Bridgeton, Me., reach the New
Hampshire boundary at Kimball's pond in Chatham, pass over Mt. Pe-
quawket, and extend through the towns of Bartlett, Hart's Location, Liv-
ermore, Woodstock, Benton, and Haverhill to Connecticut river, thence

DESCRIPTION OF THE GENERAL SECTIONS. 653

through Newbury and Topsham in Vermont, a total distance of eighty
miles.

The Maine portion of this section is believed to consist entirely of
Montalban strata, extending to the east base of Pequawket, where it dips
westerly at a small angle beneath the mountain. The mountain itself
presents interesting peculiarities, whose details are fully given on page
237. We find three kinds of igneous rocks, — a sheet of Conway granite
at the base, Albany granite in the middle, and the peculiar breccia of
Pequawket constituting the upper half of the mountain. From the Saco
valley across to the Pemigewasset nearly all the ledges are of varieties of
granite distinctly eruptive. At first is the Conway rock ; then the Al-
bany granite over the ridge around which the Saco finds it necessary to
flow northerly, or the north-eastern spur of Moat mountain. In Upper
Bartlett the Conway granite returns, extending about to the west edge
of the town. The section just touches the north edge of the Chocorua
group in two places, as piled up in the area of Mt. Tremont and its asso-
ciated summits. This lies upon a Montalban area in the Saco and Saw-
yer's rivers valleys, where the strata show monoclinal Vv^esterly dips. After
crossing a little more Conway granite, the section reaches the very inter-
esting outlier of porphyritic gneiss in Sawyer's River valley, at the south
base of Mt. Carrigain, the most northern exposure of this range known.
The relations of this rock to the porphyry of Mt. Carrigain are well shown
in Fig. 15, Plate X, save that the gneiss should be represented as dipping
east instead of west. The porphyritic area is followed by a broad expanse
of Conway granite, capped by the Albany in the upper part of the Han-
cock Branch valley, and about the forks of the east branch of the Pemi-
gewasset. Near Pollard's in Lincoln, and constituting the west border
of the eruptive area, is situated the Conway rock, probably the same with
some large eruptive dykes. Between Pollard's and the Pemigewasset
river the Montalban crops out with high easterly dips, which are evi-
dently normally synclinal. The following broad band of porphyritic
gneiss through Woodstock and Benton has not been much studied. It
is believed to underlie Moosilauke, so that both the floor and the mica
schist of the summit exhibit the basin structure. West of this mountain
are the Lake and Bethlehem gneisses, with several folds. In Haverhill
the Coos quartzite and schists are well developed, and are fully illustrated

654 STRATIGRAPHICAL GEOLOGY.

upon Plate XIV. Fig. 47 seems to follow very nearly the course of Sec-
tion VIII. Among its most important features are the numerous flexures
in the Huronian ; and the presence of the Lyman group for the first time
in our sketch of the sections, in following their numerical order. Viewed
generally, the Lisbon group is seen clearly to underlie the Lyman. They
are followed by the Coos micaceous quartzites, with reversed easterly
dips; and these in their turn by the Calciferous mica schists near the
western edge of Newbury, dipping in the same easterly direction. The
valley of Tabor creek indicates clearly an inverted basin, followed by an
anticlinal in the deepest part of the valley. The hill between this and
Wait's River village seems to exhibit the double basin character. The
great axis of the formation is reached in the east part of Washington,
while the rock continues to the east line of Northfield.

Section IX.

Section IX has been measured from the state line between Batchel-
der Grant and Bean's Purchase, through the last-named tract. Green's
Grant, Thompson & Meserve's Purchase, Sargent's Purchase, in which
the top of Mt. Washington is situated, Crawford's Purchase, Nash & Saw-
yer's Location, Carroll, Bethlehem, Littleton, and Monroe to Connecticut
river, a distance of fifty miles; thence through Barnet and Peacham in
Vermont to the western limits of the map. No attempt has been made
to traverse the part lying in Maine east of Bean's Purchase, though that
is believed to belong to the same series with those first seen within the
state.

In Bean's Purchase the rocks are altogether Montalban. From Mt.
Royce to Carter all the strata are said to dip westerly. Between the
ridge and the Peabody river there may be two flexures. Concerning the
route westward from the Peabody river, or from the Glen house to the
summit of Mt. Washington and to the base on the west side, our obser-
vations have been numerous, and are fully described upon page 1 16 and
Plate VII. The general conclusion reached is, that the mountain is
essentially anticlinal in attitude, with several subordinate flexures upon
the east side, including the very important synclinal below the Half-way
house carrying the squeezed and somewhat faulted basin of andalusite
slates. The pitch of the Mt. Washington anticlinal is westerly. Below

DESCRIPTION OF THE GENERAL SECTIONS. 655

the base station of the mountain railway is a broad expanse of a granitic
rock, hke the Concord, not necessarily stratified. Ledges are wanting
for about two miles east of the Lower Ammonoosuc falls, where the
Conway granite sheets, dipping slightly north-west, appear, constituting
the north end of the Rosebrook range. This is the only ledge seen along
the river; but the Sugar-Loaves on the southern side consist of similar
material. Shortly before arriving at the Twin Mountain house in Carroll
are indications of the presence of the typical area of Bethlehem gneiss.
The section, unfortunately for showing structure, follows nearly along
the line of strike of this formation. The nature of the axes is somewhat
uncertain. It seems clearly enough to be an anticlinal, through the
diversity of dips near the east end, but synclinal, with a monoclinal in-
clination, through Bethlehem. The lower part of the formation is por-
phyritic, while the upper is nearly a mica schist, with white feldspathic
nodules. The best argument for the basin structure is the occurrence
of porphyritic gneiss on both sides, with synclinal dips.

At Littleton two formations overlie the Bethlehem series, — first, a strip
of ordinary (Lake) gneiss, and, second, the Coos schists, the last the most
highly inclined. The last are usually between the two gneisses. On the
west occurs a narrow strip of the Lisbon group, and then alternations of
this with fossiliferous Helderberg (p. 329), The Lyman group comes up
west of the Lisbon ; and west of Partridge pond there is a range of clay
slate. The section crosses the north end of Gardner's mountain, seen on
Plate XIII to consist of several flexures closely crowded together, with an
anticlinal in the centre. The clay slate appears in scanty amount west
of the Huronian at Barnet. It is inverted beneath the Huronian of Mon-
roe, as is also the Calciferous mica schist farther west. No variation in
the dip of the latter is noted ; and in the west part of Peacham it comes
in contact with the Marshfield area of granite. This eruptive mass is
probably of diverse ages, like that of Mt. Ascutney, a part of it being
earlier, but most of it later, than the calcareous schists.

This section was first measured for the Vermont geological survey in
1858, and a view of it published in the final report of that state, connect-
ing together the White and Green Mountains. The present sketch is
not so lengthy ; but the New Hampshire portion has been greatly im-
proved over that early delineation.

656 STRATIGRAPHICAL GEOLOGY.

Sections X-XIV.

These have been ah'eady described on pages 86-97, and figured more
in detail upon Plate VI than upon our general map. We have also added
something to X and XI from Vermont, besides a great deal to XV in the
Canadian portion of the sheet. The west end of Section X in Lancaster
is obscure, the dips not being readily understood on account of the nature
of the rocks. In Lunenburg, so far as known, the Lyman group is nearly
ubiquitous, with a westerly inclination. Miles mountain is of monoclinal
westerly-dipping Montalban strata, having Lyman schists upon both
sides, so that it may for the present be set down as anticlinal. The Coos
group appears at West Concord, then the Lisbon series, probably with
easterly dips. The Waterford slate range has the same position still far-
ther west, followed by a broad expanse of the Calciferous mica schist in
St. Johnsbury, Danville, Walden, and Hardwick,

Section XI shows the continuation of the Northumberland and Lisbon
rocks into Guildhall, dipping westerly, beneath the Lyman synclinal of
Burnside mountain. The remnant of the latter is a clay slate, and the
Coos mica schists are located between this Lyman rock and the Montal-
ban of Granby. The last series is better developed than upon Section X,
and displays unmistakably the anticlinal structure. Inverted Coos schists
appear on the west side of this Montalban patch, and are believed to rest
upon the latter group, but to dip beneath the Calciferous group of East
Burke by an overturn. The synclinal in East Burke is well marked,
while an easterly dip is persistent through to the granitic axis in the cen-
tre of Sheffield, where they dijD in the opposite direction.

Reference has been made already to the west end of Sections XII and
XIII. Inasmuch as the north-west sheet could be easily drawn so as to
include a part of Canada, I have prolonged the short section XIV, (PI. VI,
Fig. I) to Massawippi lake. It exhibits next to New Hampshire, first, a
little clay slate; second, a broad band of the Coos schists; third, the Cal-
ciferous mica schist ; fourth, a repetition of the clay slate, and perhaps
the continuation of the range bordering the Calciferous group on the
west side through northern Vermont. Logan connected this slate with
the limestone succeeding it on the west, carrying Hclderberg fossils, but
on account of its situation I have believed it must be the equivalent of

DESCRIPTION OF THE GENERAL SECTIONS. 657

that in central Vermont. The Helderberg fossils described in the Can-
ada reports belong to the upper part of the series, or Devonian. The
presumption is, therefore, that these limestones upon Massawippi lake
are of Devonian age, and therefore different from those of Littleton, Ly-
man, Lisbon, and Bernardston, which are so plainly Silurian.

I regret very much not to have room enough in this volume to present
further details of these sections, and catalogues of the specimens ob-
tained, as has been done with respect to those collected along Sections
X-XIV, on pages 92-97. A hundred pages would be required to set
forth all these details in a proper manner. An opportunity may be
offered for their presentation in the future, after further study. The
facts will not be lost, being preserved in the museum at Hanover, where
they will be accessible to any one who may desire to become acquainted
with them.

S3

CHAPTER X.

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS.

E have at last reached that epoch in the development of New
Hampshire geology when it is proper to state our conclusions in
regard to the establishment of the stratigraphical column. The rocks of
each topographical district have been taken up in turn, and the most
important details of their position and mineral composition presented.
As this work has been progressing, many of the formations have quietly
found a place for themselves, and there has insensibly arisen a scheme of
classification, in some respects peculiar, but mostly similar to the general
order of the older American systems. The reference of most of our rocks
to systems older than the Silurian early commended itself in preference
to the more modern doctrine of alteration from Paleozoic sediments. It
has been our business to grapple with one of the most difficult strati-
graphical problems ever presented to an American geologist for solution,
and it would be presumption in us to claim that entire satisfaction has
been obtained. I will first attempt to show how the formations may be
classified without reference to their supposed age, — using local names
derived from the localities where each one is best exposed for investiga-
tion. This course will enable those who may not accept our views of
correspondence to establish for themselves any relation to Paleozoic
groups which will commend itself. It has been our constant aim so to
divorce the facts and theories from each other in the descriptions, that
those who hold different general views from our own will not find the
observations unwarrantably obscured by individual speculations.

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. 659

Every one will grant at the outset that onr field of labor must abound
in inverted flexures and dislocations of the strata. Those who are not
familiar with inversions will not be prepared to accept our statements at
the first reading of them, because they seem contradictory to nature. It
is only because inversions are the opposite of reality that apparently ex-
travagant statements are correct. One who will apply the ordinary rules
of superposition to the formations of a country like ours, will not only fail
to detect the true structure, but will involve himself in labyrinthine per-
plexity. If our interpretation fails in any particular it will be in the neg-
lect to invoke all the inversions and faults that are required for truthful
elucidation.

Let us take an example for illustration. A section twenty miles long
crosses a formation — say a hornblende schist — four times. The strata
all dip in the same direction, both the hornblende rock and the interca-
lated groups. The natural method of interpretation is, to say there are
four different horizons of this formation. One who has explored much
among the crystallines will find it desirable to say there is but one for-
mation, and that has been repeated three times. That view will simplify
the classification, perhaps allowing us to refer the seven separate bands
of the section to two. Cases exactly like this can be found, but usually
the same bed is not repeated so many times. The principle is one that
we are compelled to accept as fundamental, and to apply constantly.

Our older formations show a tendency to assume an ovoidal shape.
Those familiar with New England geology will recall the similar repre-
sentation of Percival's ancient groups in Connecticut, called K i, K 2,
and K 3. Our porphyritic and Bethlehem gneisses show this feature
the most markedly. Where no subsequent disturbances have modified
the natural order of the later bands, grouped concentrically around the
ovoid nucleus, an easy method of determining relative age is afforded,
even ifthe whole series is inverted. Then if there is a number of the
ovoidal areas, not very far apart, we understand the comparatively recent
origin of the rocks between them.

Another important doctrine relates to the identification of formations
in our field of labor by means of mineral characters. Allowing for a
certain degree of modification, we must believe that the same kind of
rock in adjoining counties, or for greater distances, belongs to the same

660 STRATIGRAPHICAL GEOLOGY.

age, unless there is reason of importance to the contrary. For example,
we trace one calcareous rock continuously for over 150 miles. There are
slight modifications in its appearance from place to place, and still more
so when we compare the specimens taken from the most extreme locali-
ties. I refer to the case of the Calciferous mica schist. In Canada a
considerable portion of the series is purely a limestone, with occasional
spangles of mica scattered through it. At the other extreme, in Franklin
county, Mass., the limestone is reduced to occasional strata, a few inches
thick, of micaceous character, perhaps containing 50 per cent, of calcium
carbonate, while 90 per cent, of the formation consists of a mica schist.
This modification of character is greater than is usually insisted upon for
New Hampshire. The style of similarity, made use of for identification,
is better shown in the porphyritic gneisses. There are over thirty areas
of porphyritic gneiss, in which the feldspar crystals are very conspicuous
for their size, the rock being the Augen gneiss of Europe. I assume that
all the areas of this rock are identical in age, and, in speculating upon the
relative positions of the intervening groups, rely upon the correctness of
this starting-point. A thorough study of the specimens from the several
porphyritic areas shows there are unimportant but uniform differences
between them, so that boulders which have been transported from ten to
fifty miles can be referred directly to their particular source, one or
another of these areas. The fact of minor differences would seem to
confirm our assumption of their identity in age, just as the paleontolo-
gist finds, from the presence of the same fossils, proof of contempora-
neity in rocks with dissimilar mineral character.

Of still greater consequence is the method in which flexures are dis-
posed. The following are some of their peculiarities in this field: i. Sym-
metry of flexure is common, but by no means universal. Our sections
are made much more even in the drawings than is natural. The elevat-
ing forces have crushed the strata together roughly, and we may not find
the same thickness of strata upon both sides of an axis. 2. Hence the
tenderest formations, like slates, are the ones most disarranged, the hard
bunches of granite or gneiss being incompressible, and forcing the others
out of place. 3. The vertical position does not necessarily indicate
greater antiquity than an adjacent inclination of a much smaller angle.
This appears also from the fact that the less inclined formation may

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. 66 1

sometimes have been inverted, — that is, moved more than to the perpen-
dicular position. 4. Vertical strata may be resolved into compressed
folds, — as many as the necessities of correlation seem to require. 5.
Where there is an ascending series of groups, any one of the number
may show several flexures. When their whole number is not known, the
band may seem to possess an anticlinal structure instead of both the
ridge and basin shape, or a fault may have cut away one of them. More
than one section is often required to determine the structure of a- partic-
ular band. 6. We have cases of what the older geologists called fan-
sliapcd stratification. Some such are only apparent, and are readily re-
solvable into separate folds. Others cannot be thus explained, and are
regarded as anticlinal, with the arch removed by denudation, 7. We
find several examples of anticlinals on a gigantic scale. Should these
be regarded as a single fold, thicknesses of 80,000 or 100,000 feet of
strata must necessarily exist. A careful study of some of them suggests
an origin from a double basin. The rising up of an older rock along
the centre induces the anticlinal structure, — the ge-anticlinal of Dana, —
and a continuance of the pressure produces on each side of the middle
a series of inversions, each set turned outwardly from the central line
(see p. 253); or the central line may be occupied by an eruptive rock.
This will induce, in connection with subsequent lateral force, the same
complicated anticlinal arrangement, while it will allow the belief in the
original basin shape of the formation, now appearing so very different.
We have, therefore, a basin that has the shape of a ridge for a part of its
area ; but in such a case there should be a closely compressed synclinal
upon each border. 8. A somewhat different structure will result when
there has been a sinking instead of a rising along the middle line, — the
undulation called geo-synclinal by Dana. 9. The double-basin structure
in its simplest form is one that has been very often invoked to explain
the position of our formations, particularly in Chapter IX. Its frequency
of occurrence, and the ease with which it can be made to explain the fan-
shaped and complex anticlinal structure, show it to be the normal condi-
tion of flexure in our state. Other important structural features might
be specified.

I will endeavor next to ascertain the mutual relations of several of the
metamorphic groups, commencing with what seems to be very evident.

662 STRATIGRAPHICAL GEOLOGY.

Various well ascertained sections will be mentioned, from which our
column may be constructed.

In various parts of the Connecticut valley are narrow but persistent
bands of hornblende schist, usually skirting the borders of gneiss. Near
the west ends of Sections I and II in Vermont this band is seen unequiv-
ocally to fold over an arch of gneiss. The same feature is shown even
more palpably at Shelburne falls, Mass., where the same four groups
appear successively on both sides, viz., — gneiss at the base, dipping 15 or
20 degrees; hornblende schist, mica schist, and Calciferous mica schist.
There is a similar strip along the eastern border of the gneiss between
Athens and Hartland, Vt.; and the underlying rock has the anticlinal
structure, shown from careful scrutiny upon Section V. The same belt
of rock lies above the Hanover gneiss, the Westmoreland area, and others,
with the same relative positions. The Vernon-Hinsdale gneissic area is
likewise encircled by this rock, but the dip is monoclinal : hence we have
here an example of an inversion whose genuineness cannot be called in
question. The hornblende layer occurs in a few other localities where
our information is scanty ; but the facts warrant us in assuming the ex-
istence of the same relations in the unknown as well as in the familiar
spots.

The position of the porphyritic gneiss may be gathered from two or
three classes of facts. The most extensive range, between Groton and
Jaffrey, is flanked by the Lake and Montalban groups for a large share
of its development. Going east from Warner, the Lake gneiss is well
marked in Webster, followed by Montalban schist in Boscawen. Going
south-west from the same town, after a long journey to cross the group,
the Lake gneiss is first seen, extending all the way from Grafton to mid-
dle Stoddard in immediate proximity; and next is the Montalban from
Stoddard to the state line south. The topographical distribution of these
three formations indicates very clearly a succession. From what has
been stated, either the basin or ridge structure is needed to explain the
recurrence of identical formations on both sides of the porphyritic gneiss,
which, by the way, is located along the height of land between the Con-
necticut and Merrimack rivers. Now the porphyritic gneiss possesses
the fan-shaped disposition of strata; and there is very commonly a dip
of the Lake gneisses towards it, both from the east and the west, as if

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. 663

the first-named rock capped the others. To make that view consistent,
the Montalban rocks should always dip beneath the Lake series, in local-
ities free from suspicion of inversion. Such are in Gilsum (Section III),
the Salisbury gneisses notching into the Montalban (p. 532); the well
marked anticlinal of Milan and Berlin, where the latter rock does not
press closely upon the gneiss ; and other cases. Hence the porphyritic
gneiss cannot be the superior rock. Next we have the relations of
the porphyritic gneiss to the Montalban, as in the great synclinal in
Fig. 95, between Alexandria and New Hampton, the latter being up-
permost, and likewise between Ellsworth and Sandwich, where the same
truth is apparent. Near Thorndike pond in Jaffrey the porphyritic gneiss
is distinctly synclinal beneath the Montalban. Consider, also, the mutual
relations of these groups in other particulars. In Warner and Bradford
isolated basins of Lake gneiss repose upon the porphyritic gneiss (Fig.
85), which is inconsistent with the notion that the former is underneath
the latter. Between the Center Harbor and Ashland ranges (Section
VI) the Lake gneisses are forced to conform to the porphyritic series,
though at the very western edge of the Lake series is a local anticlinal.
This agrees with the curvature of the porphyritic band from Ashland
through New Hampton and Meredith. The numerous examples of iso-
lated porphyritic areas can be explained best by their inferior position to
the adjacent schists. Some of them are arranged in lines, as from Web-
ster through Hopkinton and Weare to Greenfield.

From these facts it is inferred that the porphyritic gneiss is older than
either the Lake or the Montalban gneisses, the last being the newest
Accepting this as a starting-point, we can understand the origin of the
usual fan-shaped structure, arising from enormous pressure and subse-
quent denudation. (Further remarks to the point occur upon p. 529.)
Numerous other cases of inversion and complicated structure make them-
selves clear after accepting these conclusions, which have been stated in
the body of the report.

The place of the Bethlehem gneiss areas is not perfectly clear, though
probable. They occupy the Connecticut valley to the west of the por-
phyritic gneisses. In only one place can we find the two ancient gneisses
in contact, and that has been represented in Fig. 7, Plate VI. Between
Franconia and the Wing road are monoclinal Bethlehem gneisses, while

664 STRATIGRAPHICAL GEOLOGY.

the porphyritic rocks seem to clip beneath them. If the relations between
these two sets of rocks are properly represented in this figure, the greater
antiquity of the porphyritic series is established. For want of better evi-
dence, we have accepted this as decisive, and must so regard it for the
present. The porphyritic gneiss of Winchester is partially encircled by
the Bethlehem group, a fact that confirms the conclusion obtained from
the Wing Road section. Our order, as now set forth, is the following:
After porphyritic gneiss, the Bethlehem, Lake, and Montalban series. It
may as well be said now as at any time, that nothing older than the por-
phyritic gneiss has yet been discovered. This formation constituted the
first dry land in the state, as has been set forth in the first volume.

Another set of groups are the argillaceous, talcose or hydro-micaceous
and calcareous series. Along the Connecticut river are the Lisbon and
Lyman hydro-mica schists or greenstones, to use Mr. Hawes's proposed
terminology. The same occur more abundantly along central Vermont
east of the Green Mountains, characterized by the presence of serpen-
tine, soapstone, and dolomite, which are found likewise in the eastern
band. These two bands must be of the same age. Their dips are not
constant, so that their relations to each other must be determined by
the relations of the rocks between. Adjoining the greenstones, towards
each other, are narrow areas of clay slate. Between the two slates the
rock is mostly the Calciferous mica schist, with occasional bunches of
eruptive granite. A careful analysis of all the dips across this cal-
careous group shows the structure to be synclinal (p. 402). The very
large area of granite in the central part of this group is found showing
itself from Section VII to Section XI, ridging up the strata just as might
be expected from igneous action in connection with lateral pressure.
Now if the central group, twenty miles or more in width, extending more
than half through the state with this breadth, is a proper synclinal, and
the two groups adjacent on both sides are the same, we have the most
positive evidence in favor of the greater antiquity of the outer rock or
the two greenstone ranges.

There is no portion of this report more carefully prepared than what
relates to these greenstones and associated rocks in the Ammonoosuc
field. Our observations may be generalized thus: There is a basin
about ten miles wide, with several subordinate flexures, having the Lisbon,

CLASSIFICATION OF THE NEW HAMPSIHRE FORMATIONS. 665

Swift Water, and hornblende series for its lower division, the Lyman
argillitic schists for the second, and a thin band of conglomerate (aurifer-
ous) for its third or upper division. To establish this classification there
is no need of resort to inversion, as the strata dip naturally in the basin
form. The groups named are covered by several later series, — the clay
slate, the Coos schists, and the Helderberg area. The first two are
monoclinal, and the Helderberg rocks often stand on edge, owing to the
enormous pressure that has been exerted upon them. The slates illus-
trate finely the change from the basin to the inverted form. In Bath
the synclinal shape is perfectly distinct. In passing north the angle of
inclination increases. Hills of the Lyman and Lisbon rocks have pushed
through the slate very much as a nail punches through the same material
in the form of tiling. Patches of the upper rock in Lyman remain as
fragments of the original basin, but eventually near the Littleton line
all the dips are westerly, and of course inverted. They are in separate
parallel bands, divided by the greenstone.

There is another set of rocks, consisting of quartzites and mica schists,
called the Coos group, that seems to underlie the Calciferous group, inter-
vening between the limestone and clay slate. They all belong to essen-
tially the same period, and their precise relations to each other are not
of great consequence in the present discussion. The latest group of
strata have a well-defined horizon in consequence of the discovery of
Lower Helderberg fossils in them. They are found resting upon the clay
slates and greenstones, while fragments of the Coos group aid in the
building up of a supposed Helderberg conglomerate. For these and
other reasons set forth in the sketch of the Bernardston deposits (p.
452) it is thought the Helderberg series is distinct from and newer than
the Coos or Calciferous group ; but if the Helderberg rocks carry with
them any of our formations, it would be those named, and no others.

The next important question concerns the relations between the green-
stones and the gneisses. This answer can be given quickly, assuming
the correctness of the structure of the greenstones and calcareous groups,
as already set forth. Gneiss dips westerly beneath the Ammonoosuc
rocks, and easterly from the Green Mountain region, thus making a syn-
clinal. There is no great difference between these gneisses, and they are
referred to our Lake division in the descriptions. Some of the Bethlehem
VOL. II. 84

666 STRATIGRAPHICAL GEOLOGY,

areas are intimately connected with the eastern band. These two groups,
then, are older than the greenstones. In Hanover the apparent ascending
order is this: first and lowest, Bethlehem gneiss with the Coos schist on
its flank; next, hornblende schists; then the greenstones, followed in
Norwich by the clay slates and calcareous rocks. This is apparently
the natural order of age, the arrangement of the last three members
having been already decided upon, and it shows the hornblende rocks
and greenstones to overlie the Bethlehem group. It is more difficult
to define between the Montalban and greenstones. A section from
Success across to Dummer shows the greenstones bordered on both
sides by Montalban, dipping south-easterly. In case the eastern area
is anticlinal, as seems probable from the few facts at command, we
have a clear case of a Montalban basin supporting greenstones, making
the latter the newer rock. Our section in Fig. 5, p. 54, shows a Montal-
ban anticlinal flanked by greenstones upon both sides. In Concord and
Granby, Vt., is an anticlinal mass of Montalban rocks crossing Sections
X and XI, having the anticlinal structure. Upon the east side are green-
stones, and on passing to the next group east we find the Lake gneiss.
This section from Concord or Granby to Lancaster would afford another
synclinal basin of gneiss supporting the greenstones, but only one of
them is Montalban. Essex county, Vt., shows a large amount of ancient
rocks, evidently older than the formations of the Connecticut, Passump-
sic and Clyde river valleys. Looking to the south-west we find, half way
through Vermont, the gneiss range of Hartland and Athens. It seems
natural to believe there may be some connection between these gneisses
of Essex and Windham counties. This is important only as it carries
out the general correspondences of age in different parts of the Connecti-
cut valley. Between the Windham and Cheshire county gneisses is a
narrow strip of greenstones, seemingly in a basin. The eastern range is
continuous to the more northern section across Lancaster to Granby,
where one sees gneisses as before in Windham county, and would natu-
rally consider its relations of comparative antiquity to the greenstones
the same. Though the gneissic ridge is not continuous between Essex
and Windham, the greenstones may take its place in the gap, certainly
so far as it is related to the superior slates and limestones upon both
sides.

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. ^^J

The Labrador system, if present in New Hampshire, is in very limited
amount. Recent investigations make it difficult to say that the labrador-
ite rocks are not of eruptive character. They have the composition of
dolerite; and certain exposures of them upon Mt. Washington are surely
injected dykes. Hence great doubt arises whether the larger area of
Waterville really represents the Labrador system of Canada. At all
events, its age is great, for these dykes cut through Montalban strata.
This dolerite may be regarded as one of the oldest eruptive rocks in the
state, coming to the surface in what was the Labrador age of the world.

Next there is an enormous surface occupied by various types of mica
schist. They much resemble one another, and are confined to the region
south of Winnipiseogee lake, unless one or more of them should be made
the equivalent of the Coos group along Connecticut river. We have the
local names of Rockingham, Kearsarge, and Merrimack applied to them.
Of these the second is characterized by the abundant presence of andalu-
site ; and the formation lies unconformably upon the Montalban at Mts.
Monadnock and Kearsarge. In the sections across the mica schist group
at Derry (Fig. lOo) its synclinal structure is very obvious, resting upon
the Lake group. The Merrimack group holds a similar relation to the
gneisses, as in the Massachusetts section (Fig. 98) and between North
Andover and Salem (Fig. 109). The Merrimack rocks would seem to
rest upon the Rockingham, and probably the Kearsarge series does the
same.

The eruptive rocks are not readily assigned to comparative ages, since
the epoch of eruption cannot usually be fixed closely. There are three
general centres of their distribution within the limits of our map. The
largest is in the midst of the White Mountains ; the next occupies the
northern part of the same mountain group, divided midway by the Grand
Trunk Railway ; the third is in Essex county, Vt. Perhaps the labrador-
ite diorites, and some of the dolerites cutting the older gneisses, should
be ranked as the first rocks that have been injected. The principal erup-
tive masses seem to have made their appearance in the debatable period,
either at the close of the Eozoic or early in the Paleozoic. They are the
Conway, Albany, and Chocorua granites, sienites, and other granites.
The porphyry has preceded these granites, since fragments of the former
occur in the latter rocks. There are dolerites mineralogically like those

668 STRATIGRAPHICAL GEOLOGY.

of Triassic age in Massachusetts, and trachytes. The latter are com-
monly regarded as of volcanic origin, or later than Cretaceous. The
question of the age of these eruptive rocks is now being studied by Mr.
Hawes, and he will be able to present more satisfactory conclusions re-
specting them in his chapter on Lithology.

Equivalen'cv of New IIampsiiire For:matioxs.

Having stated the probable succession of our formations, it is proper
next to correlate them with similar groups in adjacent territory. We
find in Canada the systems Laurentian, Labrador, Huronian, and Cam-
brian. The first two of our groups may be referred to the oldest of
these, the Laurentian, without great hesitation. We do not possess ex-
haustive information about the occurrence of this oldest system in other
regions. So far as is understood, there are two sorts of associated rocks
in its typical localities, one being largely pyroxenic. That variety is
wanting in New Hampshire. A porphyritic or angcn gneiss is eminently
characteristic of the fundamental rocks in every part of the world, and
hence ours may readily be called Laurentian. The Bethlehem group,
consisting largely of protogene gneisses, is closely related to Laurentian
rocks, though not so characteristic of them as the preceding.

Those who are familiar with the crystallines, as Prof. Dana (p. 109) and
Dr. Sterry Hunt, after examining some parts of the Bethlehem group in
New Hampshire, say that there is a close resemblance between them and
the Laurentian. In a geological map of New Hampshire and Vermont,
published in 1877 for a topographical atlas of the first named state, I
have grouped these rocks, the porphyritic and Bethlehem gneiss, as
Laurentian.

The next division, the Lake gneiss, cannot be so readily assigned. Its
affinities are strongly with the Laurentian, but it is not pyroxenic nor
poriDhyritic, nor does it abound in any triclinic feldspar. The Manchester
range is thoroughly crystalline, and shows intensely twisted stratification,
features that do not prevail in the other areas. I sometimes think this
particular area, as well as its analogue in Berlin, might be separated from
the others and put into an older group. In Massachusetts this group
carries the Eosoon, but that fossil is not confined to the Laurentian.
Limestone is not usually present in this group in New Hampshire.

CLASSIFICATION OF THE NEW HAMPSIIIRE FORMATIONS. 669

The ]\Iontalban series are certainly not characteristic of the Lauren-
tian. Dr. T. Sterry Hunt has thoroughly discussed this formation in his
recent publications, to which repeated reference has been made in the
foregoing chapters. In Volume I, page 526, I proposed to have the word
Atlantic include the Bethlehem, Lake, Montalban, and Franconia groups,
signifying a system between the Laurentian and the Labrador, and
intending to restore an ancient use of the new word. After consultation
with geologists, I find this usage not altogether satisfactory. Hence in
the final classification I will drop the word Atlantic as applied to a dis-
tinctive system, using Montalban in its place. We retain the term
Atlantic, however, in a geographical sense, and understand it as defined
upon page 6. The Atlantic area includes geographically all the crystal-
line terrancs that aid in building up the mountains adjacent to the ocean
on the eastern border of the continent. There are Laurentian, Montal-
ban, and Huronian rocks within it. The Montalban will certainly em-
brace the characteristic rocks of the White Mountains, the Concord
granite, various ferruginous and fibrolite gneisses carrying the gigantic
veins, and the Franconia breccia.

There is a point not yet made clear in the discussions about the rela-
tions of the Montalban rocks. Dr. Hunt is satisfied that they overlie the
Huronian or greenstones. Our own observations lead to the view that
the typical Montalban rocks tmderlie the same, as recently stated, though
the precise relationship is not beyond controversy. There can be no
doubt of the relation between the Berlin range of Lake gneiss and the
Huronian, as shown in Fig. 6 and Section XI. These statements indi-
cate the proper place to refer our Lake series. Inasmuch as it has cer-
tain affinities with the Laurentian, and clearly underlies the Huronian,
we may for the present place it with the former, and leave the question
of the relations of the Huronian and Montalban to be settled by other
considerations. Our Laurentian column will therefore consist of the
porphyritic, Bethlehem, and Lake gneisses.

The word Huronian has just been applied to the greenstones. Much
has been said about this formation in the report, particularly a sketch of
its distribution in the best known localities in eastern America (pages
457-465). It appeared that there are two well marked divisions of this
system, the upper quite chloritic, and the lower quartzose and feldspathic.

6/0 STRATIGRAPHICAL GEOLOGY.

The greenstones of our state seem to be closely allied to the upper Hu-
ronian, and the porphyries of Lynn, etc., Mass., to the lower division. It
is possible that our supposed eruptive porphyries of the White Moun-
tains belong to this lower division. They certainly possess the same
lithological features, and in some cases have been protruded through
what we consider the upper division. A different view has been taken
of these greenstones. Sir W. E. Logan regarded them as the altered
Quebec group of the Cambro-Silurian ; and we find this view carried to
a fatal extreme by Prof. F. H. Bradley, who insists that the original typi-
cal locality on Lake Huron is the same Silurian group metamorphosed,
so that there is no such thing as Huronian in existence. If logic carries
the theory to such an extreme, we need not be troubled to defend the
Huronian, since there are few points in American geology better estab-
lished than the inferiority of the Huronian grits to the Cambro-Silurian.
We claim not merely lithological evidence to support the reference of
certain New Hampshire rocks to the Huronian system, but also that
the study of the stratigraphical relations of the several Canadian sec-
tions (Plates II, III, and IV) indicates a similarity in the order of the
various groups. The Green Mountain gneisses, being either of the Mont-
alban or Lake series, clearly underlie the Huronian in the East, just as
the ancient gneisses do in Ontario and Michigan. We have a different
classification of the Huronian in New Hampshire from t^at in Canada.
No one yet understands the system sufficiently thoroughly to institute
close comparisons, though only study is required to discover the proper
correlation.

There is no reliable evidence yet in our possession to enable us to
locate the precise place of the Merrimack, Rockingham, and Kearsarge
groups of mica schist. The first is somewhat related to the Huronian, as
well as in its argillaceous beds to the Cambrian. They are all referred to
the Paleozoic system in our table, with a large interrogation point. The
slates of the Connecticut valley are called Cambrian, because they are
supposed to be the equivalent of the Paradoxides beds. The various
members of the Coos group are ranked as Paleozoic, without direct evi-
dence of their proper place. The same is true of the Calciferous mica
schist. Logan referred it to the Niagara limestone. No fossils, except
very obscure minute crinoidal fragments, have been found in it. Noth-

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. 6/1

ing need be said of the two Helderberg series, as their relations are well
known. There are no formations in the state of later date than the
Lower Helderberg, save the surface deposits. Full details respecting
them may be expected in Part III.

Thickness of the Formations.

Making all suitable allowances for repetition of strata by flexures, I
venture to add a column indicative of the thickness of our New Hamp-
shire formations. For future reference, I will briefly state the localities
relied upon for these estimates.

The figures for the surface deposits are taken from a general impression
of the viaxinia. The thickness of the North Lisbon Helderberg has been
roughly estimated at 500 feet (p. 338). In the Vermont report (vol. i, p,
449) the thickness of the Coventry Upper Helderberg deposit is esti-
mated at more than 200 feet. The Calciferous mica schist, at its min-
imum, perhaps, is given in the same report (vol. ii, p. 617) as 4,800 feet.
I have used the thickness of 3,000 for staurolite slate and 3,300 for the
mica schist of the Coos group, from the measurements taken from the
section in Fig. 28. On the Orford section the same are respectively
2,700 and 2,700 feet.

On the Lyme section they are 2,250 feet (reduced one half from the old
measurement in the annual report, to allow the further folding indicated
in Fig 54) and 1,500. The green schists following, 3,791 feet, may pos-
sibly be the equivalents of the Calciferous mica schist. In Hanover the
slates amount to 2,400 feet and the schists to 2,100. These various
measurements indicate that the thickness is not constant. The quartzite
in Hanover is 800 feet, and in Orford 1,000 feet thick. I will use double
the thickness stated in conection with Fig. 28 for the clay slates (Cam-
brian), because the inversion supposed to be present is doubtful, and 3,000
feet will better express our notion of the usual thickness of this formation.

In Andover the thickness of the Kearsarge group (Fig. 103), allowing
five foldings, would be 1,300 feet. The Rockingham group cannot be
measured satisfactorily. The average of two attempts (Figs. 99, 100)
gives us 6,000 feet. For the Merrimack group, the thickness of one side
of the Epping synclinal (Fig. 106) is taken for the standard.

The thickness of the Huronian members is taken from Fig. 28, except

6/2 STRATIGRAPHICAL GEOLOGY,

the hornblende group. We assume fifteen sixteenths of a mile as its
breadth, and 40° as the average dip o£ this band in Hanover. Dividing
the result by two, the quotient is 1,580.

For the Montalban series, I will figure only upon the fibrolite and the
ordinary series. The first, three tenths of a mile wide, at an angle of 60°,
will show 1,370 feet thickness. Perhaps a fair average of the Montalban
series may be obtained from a section between Glen Ellis falls and the
north base of Mt. Pequawket, allowing for two folds and an average dip
of 50°. This is not satisfactory, but the result of the calculation, approx-
imately 10,000 feet, expresses fairly our idea of the thickness of the series.

For the thickness of the Lake series I have calculated the breadth of
one half the Manchester range, or from Hallsville to near the south-east
corner of the township, three and three fourths miles, at an average dip
of 70°, making 18,600 feet. The breadth of the Bethlehem series in
Hanover is calculated to be about 6,300 feet. The upper division may
be estimated as 5,000 feet. Taking the broadest part of the porphyritic
gneiss from Washington to Warner (Fig. 85), and allowing for seven
flexures, we shall get 5,000 feet thickness for it.

Geological Map.

Constant allusion has been made to the general geological map of the
state in the descriptions of the rocks. This has been drawn upon the
scale of two and a half miles to the inch, and contours for every one
hundred feet of altitude. It embraces portions of Maine, Vermont, and
Quebec, and is engraved upon six sheets. The facts embodied upon it,
both topographical and geological, have been derived from our survey.
The formations represented are essentially those of the stratigraphical
column given on a subsequent page, with such variations as the state of
the case or the degree of knowledge allows. Many persons will recog-
nize in it the features of a topographical atlas of the state recently pub-
lished by Comstock & Kline. These gentlemen were allowed to use our
delineation for their map. Quite a number of improvements in detail
over this subscription map will be found upon it by those who examine
the topography critically, and it covers a larger area. Many geological
facts are added, besides the difference in paper and the elegant coloring.
In case the distribution of the formations differs from the description of

Pl.atkXXM.

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS. 673

them in Part II, it should be remembered that there has been an oppor-
tunity for adding improvements since the printing of the text. Any
points of great importance may be noticed hereafter in an appendix to
Vol. III.

Axial Lines.

It has not been possible, till the last sheet has been printed, to prepare
a diagram illustrating some of the principal anticlinal and synclinal lines
of elevation or depression throughout the state. The general map is in-
tended to show all the important dip-observations that have been taken
and mentioned in the text, with a few additions. It may not be practica-
ble to draw these lines upon the general map, so I have prepared a small
sketch to show the principal ones, both in New Hampshire and Vermont,
in Plate XXVI. This is the final summing up of all the multitudinous
observations of this report. Very much might be said to good purpose
respecting them, but our limits will not permit. This map and the state-
ments of the last few pages are the key to Part II. They are the gene-
ralizations derived from our entire work, both in the New Hampshire
and Vermont surveys.

The Atlantic Area.

Since the printing of Chapter I, more knowledge has been acquired
respecting the distribution and equivalency of several of the groups in
the territory adjacent to us. For example, the upper division of the Nova
Scotia Carboniferous (p. 21) has been referred to the American represent-
ative of the Permian. The Mascarene series (p. 16) is now definitely
known to belong to the Upper Silurian. The Canada reports claim the
occurrence of the Medina group in the St. Lawrence valley, while no
fossils of the period have yet been discovered in the red slates believed
to be of that age. I have brought together upon page 675 a list of the
larger stratified groups known to occur in the middle section of the
Atlantic area. A comparison of the two columns will show that the
later systems are absent from our state, while nearly every one of them
is represented in the middle section of the Atlantic area.

VOL. IL 85

6/4 STRATIGRAPHICAL GEOLOGY.

FORMATIONS IN NEW HAMPSHIRE.
I. Stratified Groups.

Thickness

U f Modified drift, including kames, gravel, and sand deposits, Champlain '" feet.

clays, 250

200

W (

U V Total Cenozoic, 450

'Upper Helderberg (Vermont), 200, Lower Helderberg, 500, . . 700

Calciferous mica schist, 4,800

g r Staurolite slate, 3,000

c i Mica schist, often stauroliferous, 3, 300

g [Quartzite, 1,000

Cambrian slates (Connecticut valley), 3,000

Total Paleozoic, 15,800

Kearsarge andalusite group, i ,300

O Rockingham mica schist, 6,000

O ■> Merrimack group, 4,300

21

g I Glacial drift

Ferruginous slates, with steatite (probably repetition of preceding),

Total Paleozoic? 11,600

( Auriferous conglomerate, 50 to 300

Lyman group, 2,330

Lisbon group, containing steatite and serpentine, .... 3,539

Swift Water series, 4,400

^ Hornblende schist, 1,580

Total Upper Huronian, 12,129

Lower Huronian, porphyries of Massachusetts,

Labrador system,

Franconia breccia, ..........

Fibrolite schists, with gigantic granite veins, . .... 1,370

< ^ Ferruginous schists, .........

Concord granite,

^ Gneisses and feldspathic mica schists, 10,000

Total Montalban,

Lake Winnipiseogee gneiss, .......

Bethlehem gneiss — fine-grained,

g J Bethlehem gneiss— ordinary,

Porphyritic gneiss,

Total Laurentian, 34,900

Total, 86,249

11,370

18,600

5,000

6,300

5,000

CLASSIFICATION OF THE NEW HAMPSHIRE FORMATIONS.

^7^

11. Eruptive Masses.

Conway granite,
Albany granite,
Chocorua series,
g \ Granite cutting Coos group,
Granite not otherwise assigned,
Sienite of Mt. Gunstock, etc.,
Exeter sienite and diorite (Quincy),

Labradorite diorite,
Porpliyry,
Pequawket breccia,
Trachyte.

Diorite,
Dolerite.

FORMATIONS REPRESENTED IN THE MIDDLE SECTION OF THE
ATLANTIC AREA.

O (

N]

Quarternary,
i 1 Tertiary.
U I

Cretaceous,
Triassic.

f Permo-Carboniferous,

y Carboniferous,

O

N Devonian,

^\

W Silurian,

I—]

< Cambro-Silurian,

Cambrian.

U
O J.

Huronian,
Labrador,
Montalban,
Laurentian.

I

INDEX TO VOLUME II.

Page.

Adirondack area, .... 6
Albany granite, 142, 150, 153, 163, 183
261, 605, 667
Amalgamator, Rae's, figure of . . 517
Ammonoosuc gold field, . . . 272
Andalusite slate, 116, 164, 175, 232, 259

585

Appalachian mountain club, . . 268

" system, how restricted, 7

" referred to by Rogers, 191

Argillaceous mica schists, . .421

Ascutney area, geology of . . 403

Atlantic area defined, ... 6

'♦ rocks, 8, 10, 54, 67, 252, 276

669, 673

Auriferous conglomerate, . . 303

Axial lines 673

Basin in Franconia, . . .158

Beaver falls, . . . . 47, 150

Bethlehem gneiss, 104, 348, 409, 428, 473

663, 666

Berlin gneiss, 11 r

Beryl, place of, . . . • SH

Boston basin, 23

Boulder from Bemis brook, . 182, 241
Breccia granite, . . . .169

Page.

Catalogue of specimens from White

Mountain district, . . . 243

Catalogues of sections X-XIV, . 92
Cave in Berlin, .... 79

Cenozoic, . . . . .21

Chocorua group, 154, 181, 230, 262, 406

667
Champney falls, . . . .150
Classification of formations, . . 658
Clay slate, . 279, 311, 326, 367, 432

Conclusions as to Bernardston area, 452
" porphyritic gneiss, 529

" quartz bands near

Manchester, . 548
Conclusions as to White Mountain

rocks, 251

Concord granite, . . 112,161,570

Connecticut valley district, geology of 271

Continent, growth of ... 4

Conway granite, 142, 151, 163, 174, 183

261, 605, 667

Coos and Essex district, geology of, 37

Coos group, 18, 36, 278, 316, 578, 420

424, 442, 665, 670

" quartzites, . 372, 412, 416, 436

" slates, 392

Copper on Gardner's mountain, 288, etseq.

Cretaceous, 21

Crumpled strata, . . . 119.383

Calciferous mica schist, 41, 395, 426, 665

670
" in Vermont, 399

Calciferous sandrock, . . .13
Cambrian, 13, 16, 23, 279, 311, 367, 432
628, 668
Carboniferous, .... 20

Catalogue of specimens from Am-
monoosuc field, .... 343
Catalogue of specimens from Coos

county, 81

Catalogue of specimens from Held-
erberg section, .... 446

Dana on Bernardston rocks, . . 449

" Franconia gneiss, . . log

" White Mountain notch, . 180

Devonian, ... 19, 194, 263

Devil's Slide, 69

Dykes, . . 76, 116, 137, 157, 632

Dolomite, 298

Dwight, Pres., on White Mountains, 184

Eagle Cliff, 151

Elevation of White Mountains, 254, 263

Gyd,

INDEX TO VOLUME 11,

Page.

Eozofin, . . . 22, 6i6, 629, 668
Eozoic system, New Hampshire rocks

belong to 264

Equivalency of N. H. formations, 668

Eruptive rocks, 136, 427, 603, 630, 667

675
Essex county, Vt., 31, 54, 55, 64, 198, 666

Ferruginous schists, .

Fibrolite gneiss.

Flexures of strata, . . . ,

Flume, Franconia, ...

Hitchcock, on Mt.Willard, 1 7
Fossils in Helderberg,
Francestown soapstone, .
Franconia breccia, .
Frankenstein cliff,

489. 573

• 494
. 660

157
242

• 339

• 590
^Z7, 2S7
I So, 229

Gaspd slate, 17

" sandstone, .... 19

Goodrich falls, 146

Gold mines, 41, 298, 304, 308, 312, 318

Granite,

" of Manchester, .
" of Green Mountains
" of Moose mountain, .

of Haverhill,
" ofHooksett,
" Coast district, . . 62
(For granites of Albany, Breccia
Chocorua, Concord, and Con
way — see under those names.)
Granitoid gneiss.
Grand Trunk Railway, rocks alon
Green Mountain axis,
Green's cliff, ....
Guyot on the Appalachian Mountain
system

73, 509
554, 566
609
605
379
550
632

74

25, 31
151

Hawes, G. W. .
Helderberg, Lower

14.

• 232,
18, 208, 325

•' Upper ....

" sea, ....

" section, geology of

Hitchcock, C. H., chapters by 3, 98,

518, 592, 611, 634,

E. . . . 187,448,

" flume, . . . 171,

Hornblende schist, 284, 324, 365, 378,

Hubbard, O. P

Hunt, T. .Sterry . . 196, 252,
Huntington, J. H., chapters by 37,
on eastern part of the White
Mountains, ....
on limestone in Plainfield, .

on Mt. Lafayette,

666

444
665

19

342
428
271
658
629
242
430
662
185
274
466

127
396
160

Huntington, J. H., on rocks alon
G. T. R.,
on rocks in Maine,

" of part of Connecticut

Valley district,
" of country south of the
Saco river.
Section XI V-XX,

Page.

i8g
204

408

148
86

Huronian, n, 39' 47, 53, 209, 234, 259
277, 355, 411,664, 669
of Atlantic states, . . 465

of Michigan,

of New Brunswick,

of Ontario,

of Quebec,

of Vermont,

458
459
457
463
464

Intrusive rocks (see also Eruptive),

68, 131, 506
Inversions, ..... 659
Isles of Shoals, .... 624

Jackson, C. T. .

Kearsarge group.

. 186, 235, 624

502, 585, 627, 667

Labrador system, 8, 11, 209

LaMotte limestones,
Laurentian, 8, 9, 209, 251, 273
(See, also, Bethlehem, Lake,
Porphyritic gneiss.)
Lake gneiss, 74, in, 472, 476,

Lesley, J. P. . . . 194,
Lenticular drift hills.
Limestone, 41, 112, 129,319,326,
341, 349, 351,
Limestones, Cambro-Silurian, .
Lisbon group, . . 277, 280,
Loraine shale, . . . .
Lyman group, . 50, 277, 293,

, 257, 667

• 32
, 468, 668
and

, 531, 665
595, 612
202, 452
446, 638
329, 338
396, 599

• 14
358, 66s

14, 32
356, 665

Macfarlane, Thomas, on Huronian, 460
Maine, geology of part of 203, 609, 625
Map of Ammonoosuc gold field

" Cobs county,

" Helderberg section,

" New England,

" North America, .

" part of Lyman,

" White Mountain district,
General map,
Mascarene series.
Mica schists of Connecticut valley, . 424

275, 280

29s

80

428

7

5

295

243

672

16, 673

INDEX TO VOLUME II.

Mica quarries, .
Merrimack group,

Mountains :

Mt. Adams,

Andalusite,
Ascutney,
Bet, .
Blue Job, .
Carr, .

Cropple Crown,
Chocorua, .
Clay,
Cuba,
Croydon, .
Carrigain, .
Cardigan, .
Clinton,
Dartmouth,
Deception,
Delight, .
Field,
Flume,
Franklin, .
Gunstock, .
Haystack, .
Israel,
Jackson, .
Jefferson, .
Kearsarge,
Kinsman, .
Lafayette, .

" range-
Lovewell, .
Lowell,
Liberty,
Lyon,
Moat,

Monadnock, Vt.,
Monadnock,
Madison, .
Monroe,
Moosilauke,
Misery,
Oseola,
Pack Monadnock,
Passaconnaway,
Pequawket,
Pleasant, .
Pleasant, Me.
Prospect (Holder
Pawtuckaway,
Starr King,
Stinson,
Sugar Loaves,
Sable,

Silver Spring,
Sunapee, .
Tom, . 144,

Tripyramid,

[53

Page.

>59, 288, 621, 667

[64

403, 647

62s

62Q

495
625
232
115
373
yil, 4^0
147, 22s
468
122
124
124
603
177
157
121
606
160
203
122
113
58s
102
261
223
524
225

157
64, 71

159. 239

• 69
503> 639
ii3> 233

. 121
473, 495

• 590
155. 195

580, 620, 639

[44

160, 2:

24,

155,

203,

211,

28,

121,

216,

162,

229

151

184
609

• 593
. . 632

• 71
• 469, 565

• 143
. 229
. 229

227, 240, 261
. 211

Mt. Wantastiquit,
Washington,
White face,
Webster, .
Welch,
Willard, .
Willcy,
Weetamoo,
Uncanoonuc,
William, .

RTcntntahi :

679

Page.
. . . 423

9, 116, 185, 195, 253
. 104, 228

123, 171, 173
. • 135

164, 177, 240

. 175

• 204, 56s

• 545
. 581, 641

Crotched,

Green,

Gardner's,

Fort

Lyndeborough, .
McKay, ,
Nottingham,
Moose, Hanover,

" Strafford county,
Ossipee, .
Profile,
Ragged, .
Sanbornton,
Temple,
Squam,
Twin,

Ni//s :

Blue,

Bean,

Green,

Pine (Gorham),

Red,

Green's cliff,

Kilburn peak, .

Nubble, .

Sandwich Dome,

Tumble-down Dick,

• 536

. 609
. 288
529, 620
580, 620
579. 620
529, 620

375
605
604
158

587
568
580

593
224, 239

. 620

579
. 152

113.233

203,

608

151
410
III

593
603

Mountains, names of . . . 267

Montalban rocks, 65, 67, 112, 127, 131

162, 253, 410, 500

563, 600, 616, 666

" relations of, to Hu-

ronian, . . 666
Mt. Washington river, . . 124, 217

North America, map of

" " rocks of

New Brunswick, rocks of
New England, map of
Newfoundland section,
" rocks of

Niagara limestone, .
Nomenclature of mountains,

12,

S

4
18, 20

7

7

9, 12

18

267

680

North Carolina mountains,
Nova Scotia, rocks of

INDEX TO VOLUME II.

Page.

7

Page,

Section from Berlin to West Milan, 55, 669

Opinions respecting White Mountains,

184, 251

" Bernardston, 44^

Oriskany sandstone, . • 205

Olenellus, . •' • • • ^2^-7

Paradoxides, . • 16, 23, 27, 265,
Pemigewasset rocks, . • 142,

(See Albany, Conway, etc.)

148, 235, 262

Pequawket breccia

Perkins, G. H., ....

Pierce, James

Pool. Franconia . . . •
Porphyrite, . • \ .' ,1
Porphyry, 148, 222, 260, 604, 667

Port Daniel limestone,
Porphyritic gneiss, 8, 9, 98, 468, 514,
602, 662,

P. &0. R. R.,

Potsdam group, . • I3' i"

Problem of New Hampshire geology,

21

184
158

70
670

18

593

668

166

27

36

Quartz of Belknap county,
" " of Rockingham group

" of Lisbon group, .

" of Lyman group, .

" in gneiss,

" in Lake district, .

" Hooksett range, .

" Manchester range,
Quartzite, Coos, . 372, 41
Quebec group, .

metamorphic,

(Same as Huronian.)

581

570
619
282

. 506
. 598

• 539
. 541
6, 436
13, 26

• 39

Relations of N. H. Geology to that of

adjoining territory, . . • 3
Rockingham schist, .
Rogers, H. D. and W. B.
Mountains,

Section L
II,

III, .

IV, . . • 107

V,

VI, .

VII, .

VIII, .
IX,
X,
XI,

XII, .

XIII, .

XIV, .
Section from Belmont to Gilmanton,

576, 616
White

. 187
. 636

638,582
. 640

109,

397.

Dalton to Carroll,
Dummer to Millsfield, 54,
Franconia to Bethleh'm,

99.

Hartford, Vt., to Craft's

hill, ....

" Mt. Desert in Maine to

Bourg Louis, P. Q.,

Mt. Lafayette to Mt.

Tom,
Mt. Monadnock, Vt., to
Columbia,
" Northumberland to Pas-

sumpsic river, .
Northumberland to Pi-
lot mountain, .
" Plymouth, Mass , to

Whitehall, N. Y., .
Portland, Me., to Aber-

crombie, P- Q.,
Sherbrooke, P. Q., to
Connecticut lake, .
" Stark water station to

Milan,
Tamworth to White's
ledge, .
" Townsend to Groton,

Mass.,
" Tin to Hancock moun-

tain,
Section across the Ammonoosuc gold
field,
Mt. Kearsarge,
" Sanbornton, . _ •

Sections across Gardner's mountain,
Hillsborough county
quartz, .
Sections, delineations of, at Hanover,
illustrating the Merrmiack

642

645

647

564

237

109

666

666

88

87

86

578

no

666

109

362

32

261

67

65

52
261

585
146

277
586

287

544
634

group,
in Haverhill,
in Helderberg rocks,
in Lyme, . . . •
in Orford, . .
in Piermont,

in Hanover, . • 388
in Lebanon, . • 389
in Andover,

in Cambridge and Errol, •
in Cornish, . • 39^

in Claremont,
in Dalton and Whitefield,
in granite near Twin Moun-
tain house,
in Norwich, Vt.,
in Thornton,

through Mt. Washington, .
thro' Swift Water village,
along state line from Win-
chester to Guilford, Vt.,

62s

. 348

326-336

. 384

381
380
393
392
587
51
. 397
398
no

143
361
135
n6
320

438

INDEX TO VOLUME II.

68 1

Page.

Page.

Shephard, C. U.

. . . 184

Bradford, Vt., .

• • . 358,368

Serpentine,

. 49

Eraintree, Mass.,

i6, 630

Sienite, 68, 214,

228,

606, 630, 633, 667

Brattleboro\

• 427, 433, 630

Silurian, .

.

13. 17

Brentwood,

612, 619, 625, 630

Soapstone,

348,

382, 583, 589, 590

Bridgeport, Conn.,

ID

Stratigraphical col

amn.

. . . 674

Bridgeton, Me.,

. 609

Swift Water series

278, 320, 356, 665

Bridgewater,
Brighton, Vt., ,
Bristol,

. 490, 655, 648

88, 401
. . . 566,578

Taconic rocks, .

. 25

Brookfield,

• 599, 603, 605

Thickness of New

Ham

pshire rocks, 671

Brookline,
Brunswick, Vt.,

. 588, 636
. . 55, 66. 88

Towns, Index to

Burke, Vt.,

. . . . 67

Academy grant.

• 53, 59, 73r S7

Cambridge,

. 52, 54, 61, 65

Acton, Me.,

599.

610, 626, 627, 645

Camp ton.

99, 102, 204, 563

Acworth, 413, 421

425.

482, 510, 516, 642

Canaan, .

431, 468, 473, 479, 648

Albany, 132, 143,

148,

153, 183, 226, 235

Canaan, Vt., .

43,88

261, 610

Candia, .

553, 556, 612, 614, 640

Alexandria,

. 469, 519, 566

Canterbury,

• 577, 588

Alfred, Me., .

616,

626, 630, 632, 645

Carroll, .

75, 99, 105

Allenstown,

24, 550, 577, 616

Carlisle, .

. 259

Alstead, 411, 414,

425-

473, 482, 499, 516

Center Harbor,

• 594, 597, 648

Alton, . 594

603,

607, 612, 616, 645

Charlestown, 367,

371, 412, 421, 425, 642

Amherst, 542,

546,

552, 557, 579, 638

Charlestown, Vt.,

. 88,408

Andover, .

522,

564, 56S, 585, 645

Chatham,

127, 143, 227, 237, 262

Andover, Me., .

. . . 609

Chelmsford, Mass

. 616

Andover, Mass.,

.

. 615,611,616

Chesham, P. 0.,

. 56

Antrim, . 525,

53i>

535, 563, 573, 641

Chester, .

. 612, 614

Ashby, Mass., .

• 559

Chesterfield, 415,

423, 426, 428, 433, 468

Ashland, .

99.

490, 563, 592, 648

474, 486, 509, 519, 638

Athol, Mass., .

• 527

Chichester,

. 572, 642

Atkinson,

.

. . 623,631

Claremont,

272, 364, 370, 377, 390

Auburn, .

. 555, 614, 619

398, 409

Auckland, P. 0.,

• 44

Clarksville,
Clifton, P. 0.,

40, 46, 59, 77, 88
44, 92

Barnet, Vt.,

• • • 367

Colebrook, " .

40, 42, 46, 68, 77

Barnstead,

.

563, 570, 572, 612

Colebrook Academy grant, . 41,45

Barrington,

. 612, 642

College grant, .

• • • 53, 59, 74

Bartlett, 29, 124

132

137, 146, 148, 151

Columbia, 40

62, 69, 78, 88, 200, 259

221

227, 235, 261, 269

Concord, 112

,519, 529,571,575, 642

Bath, 272, 280

285

295, 312, 321, 665

Concord, Vt., .

. 54,65,67,281,666

Bean's Purchase,

. 127, 209, 221

Contoocookville,

• 571

Bedford, .

542, 552, 557, 579

Conway, .

. 142, 151, 234

Bellows Falls, Vt.

, .

. 410

Cornish, . 272

364, 370, 390, 396, 645

Belmont, .

. 570, 578, 64s

Cornish, Me., .

. 610

Bernardston, Mass

•,39

208, 340, 372, 402

Craftsbury, Vt.,

II

428, 444, 450, 454

Croydon,

373,377,481, 507,645

Bennington,

.

. . . 526

Cuttingsville, Vt.,

• 230

Benton, 99, 319

372

417, 472, 477, 495

519

Danbury,

. 521,566

BerHn, 55, 68,

73, 79, 91, III' 202, 234

Danville, .

619, 620

Berwick, Me., .

. 616, 625, 630

Danville, Me., .

. 203

Bethel, Me., .

. 203

Dalton, .

. 52, 55, 68, 274

Bethlehem,

100, 104, 274, 318

Deerfield,

• 553, 612, 632

Biddeford, Me.,

II, 610

Deering, .

• 531,535,573,641

Bloomfield, Vt.,

43, 88

Denmark, Me.,

. 609

Boltonville, Vt.,

.

• 357

Derry,

560, 581, 619,628, 638

Boscawen,

531, 569, 575, 588

Ditton, P. Q., .

41,44

Bow,

.

• 572, 641

Di.xville, .

12, 51,60, 74, 78, 259

Bradford, .

471

520, 524, 531,642

Dorchester,

373, 418, 473, 479, 497

VOL. II.

86

682

INDEX TO VOLUME II.

Dover,

Dracut, Mass.,
Drewsville,
Dublin, .
Dummer,

Dummerston, Vt.,
Dunbarton,
Durham, .

Page.

II, 620, 631

591, 631, 636

. 410

471, 490, 503, 526

[2, 52, 55, 61, 66, 80

201, 259, 666

. 400, 427, 432

536, 570, 572, 641

. . . 631

Easton, 476

East Kingston, . . . .631

East Haven, Vt., . . .31,43,67
Eaton, ...... 600

Effingham, 549, 598, 600, 602, 609, 647
Eliot, Me., .... 625, 630
Elkins's Grant (Livermore), . . 99

Ellsworth

Enfield,

Epping,

Epsom,

Errol,

Erving's Location

Eustis, Me.,

103, 468, 495

376, 389, 420, 467, 474, 479

560, 612, 615, 619, 625, 640

577, 579, 620, 627, 642

52,61, 74,88, 259

. 60

207

Exeter,

II, 216, 609, 621, 625, 630

Fairlee, Vt.,
Farmington,
Ferdinand, Vt.,
Fisherville,

Fitzwilliam, 490, 494,
Flagstaff, Me.,
Francestown, .
Franconia, 99, 105, iii,

Franklin,
Freedom,
Fremont,
Fryeburg, Me.

311, 358.367,387

612, 616, 620, 627

. 88

• : • 576

502, 512, 519, 637

. 207

526, 531, 535, 590
138, 142, 157, 252

255, 257

. 563, 558, 645

. 602

. 612,915,619

. 600

569,

Gilead, Me., .
Gilford, .
Gill, Mass., .
Gilmanton, . 579, 578, 607,
Gilsum, . . . .418,
Gloucester, Mass., .
Goffstovvn, . . . 542,
Gorham, . . 54, 66, 75, 113,
Goshen, 467, 473, 481, 490, 498,
Grafton, 467, 469, 473, 480, 497,

Granby, Vt., . . 31, 43, 67,
Grantham, 376, 390, 468, 473,

Granville, Mass

Great Falls,

Greenfield,

Greenland,

Greenville,

Groton,

526, 548,

529, 548,
467, 469, 473, 496,

• 203
594, 607
432, 446
611, 645
490, 642

544, 579
115, 202

510, 515
506, 515
518, 521
204, 666
479, 507
645
II
619, 642

574, 591
625,631
551,637
514, 518
521,648

Page.

Groton, Mass., . . .23, 585

Groveton, . 52, 63, 72, 78, 91, 200

Guildhall, Vt., . . 31, 54, 64

Guilford, Vt., . . 428, 432, 438, 637

Hampstead, 560, 591, 612, 615,

Hampton,
Hampton Falls,
Hancock,
Hanover, 105, 35:

623,

Harrisville,

Hartford, Vt., .

Hartland, Vt., .

Harvard, Mass.,

Haverhill, 272, 319, 348, 356,

360, 363, 367,
387, 393, 430,
• 471,
360, 369,
360, 367, 387,

Hebron, 467,

Henniker,
Hereford, P. O.,
Highgate, Vt.,
Hiil,

Hillsborough, .
Hinsdale. 423, 428,
Holderness,
Holland, Vt., .
Hollis, .
Hooksett,
Hopkinton,
Hudson, .

Island Pond, Vt.,
Isles of Shoals,

496, 514, 566,
520, 524,531,

. . 563,

• 524,
436, 442, 452,

99, 490, 565,

. 539,
519, 528, 531,

623, 631
638

. 623
626, 632

. 526
373< 379
474, 649
490, 500
387, 400
396, 403

• 23
372, 378
418,473
576, 648

575, 589
44,46

568, 587

531,535
468, 472
593, 648
43,88
563, 581
549, 641
575, 642
562, 636

66, 74, 199
28, 624

Jackson, 29, 36, 112, 127, 142, 146, 216, 221

227, 229, 234, 259, 262

Jaffrey, . . . 471,490,519,638

Jefferson, 31, 55, 68, 71, 74, 80, 91, 108, 228

Keene, 24, 418, 426, 473, 485, 499, 50S

Kennebunk, Me.
Kensington,
Kilkenny,
Kingston,
Kirby, Vt.,
Kittery, Me., .

Laconia, .
Lake Village, .

511

11

631, 632

. 75, 80, 91, 228

620,623,631,638

• 67, 367
. 625, 640

• 569, 593
569

Lancaster, . 31, 52, 55,64, 68, 91, 259
Landaff, 112, 272, 281, 318, 372, 416, 472
476, 495
Langdon, . . 410,414,421,425

Lawrence, Mass., . . . 626, 636
Lebanon, 352, 360, 366, 374, 389, 393

Lebanon, Me., . . . 627, 630

Lee, 620

Lempster, 467, 473, 482, 498, 5 16, 519, 642
Limington, Me., .... 610

INDEX TO VOLUME II.

683

Page.

Page.

Lincoln, 99, lor, 109, 131, 137, 156, 209

New Durham, 595, 599, 603, 606, 612, 616

220, 257

632, 645

Lisbon. 105, 272, 279, 2S2, 317, 321, 335

New Hampton, . . 567, 592, 648

Litchfield, 638

New Haven, Ct., ... 12, 17

Littleton, 39, 68, 105, 207, 263, 272, 276

New Ipswich, 24, 541, 548, 551, 559, 574

292, 301,315- 325030,341,451

579, (-'37

Livermore. (See Elkins's grant and

New London, .... 469, 520

"Pemigewasset.")

North field, . . . 531, 570, 577

Londonderry, 556, 581, 583, 591, 65S

Northfield, Mass., . 428, 442, 454, 526

Loudon 571

Northfield, Vt., . . . .401

Lunenburg, Vt., . . . • 54, 65

Northumberland, 52, 63, 71, 80, 90, 200

Lyman, 16, 20S, 272, 279, 293, 296, 313

207, 228, 259

368

Northwood, . . .612, 620, 642

Lyme, 272, 350, 360, 365, 373, 379- 393

North Andover, Mass., 612, 615, 629, 636

430

North Hampton, .... 632

Lyndeborough, 540, 546, 551, 577, 620

Norwich, Vt., . . . 360, 366, 369

Nottingham, . . 24,619,625,632

Machiasport, Me., . . . .16

Madbury, .... 620, 631

Odell, ... 55, 66, 74, 80, 88

Madison, .... 252, 600

Orange, .... 480, 497, 515

Maidstone, Vt., ... 54, 66

Orford, 272, 350, 360, 365, 373, 379, 382

Manchester, . 10, 538, 541, 554, 581

418, 430, 478

Marlborough, 24, 490, 500; 511, 517, 638

Ossipee, . . . 11,598,604,647

Marlow, 468, 482, 490, 499, 517, 519

Martin's Grant, . . . 75, 114

Paris, Me., 203

Mason, . . 24, 543, 552, 559, 636

Parsonsfield, Me., . . . 610,647

Mclndoe's Falls, Vt., . . . 286

Pelham, 519, 529, 562, 591, 621, 626, 636

Mechanic Falls, Me., . . . 203

Pembroke, 572

Meredith, 592

"Pemigewasset" (Livermore), 131, 145

Meriden, 395

260, 263

Merrimack, . . , 558, 585, 638

Pepperell, Mass., . . . -585

Methuen, Mass., . . . 626, 636

Peterborough, . . . 526, 538, 638

Middleton, . . . 603, 606, 645

Piermont, 359, 367, 373, 379, 393, 418

Milan, 12, 52, 55, 62, 67, 75, 80, 90, 201

Pittsburg, . .12,17,40,43,59,77

259' 323

Pittsfield, .... 579, 620

Milford 543, 557, 638

Plainfield, 360, 366, 367, 376, 390, 396 431

Millsfield, . 52, 54, 61, 74, 78, 88

Plaistovv, 623

Milton, . . . 599, 620, 626, 645

Plymouth, 490, 497, 510, 565, 576, 634

Monroe, .... 272, 286, 290

Pomfret, Vt., 400

Montpelier, Vt., . . ir, 17, 19,635

Portland, Me., ... 23, 28

Montreal, P. O., . .11, 14, 32, 208

Portsmouth, . . 623, 624, 633, 640

Mont Vernon, . . . 551,579

Pownal, Me., 203

Moultonborough, . . . 597, 606

Putney, Vt., 25

Mt. Desert Island, Me., ... 32

Quebec, P. 0., . . .12, 463

Nashua, . 562, 581, 584, 619. 62S, 636

Ouincy, Mass., . 11,607,609,630

Nelson, . . .197, 468, 472, 490

Newbury, 368

Randolph, . . 68, 73, 75, 108, 203

Newbury, Mass 616,629

Raymond, . . 614, 619, 627, 640

Newburyport, Mass., . 10,621,632

Reading, Vt., 645

Newbury, Vt., . . . 356, 359

Richmond, . 467, 473, 486, 490, 501

Newcastle, . . . 623, 624, 640

Rindge, 24, 468, 490, 493, 502, 537, 637

Newfield, Me., . . 610,616,627

Ripton, 12

Newington, .... 622, 640

Rockingham, Vt., . 12, 367, 411, 432

Newmarket, 631

Rochester, . . .616, 627, 642

Newport, . . 373,421,424,481

Rollinsford, 630

Newport, R. L, . . . . 12

Roxbury, . . . 490,499,511

Newton, 638

Royalston, Mass., . 24, 526, 538, 543

New Bedford, Mass 10

Rumney, 99, 103, 468, 478, 496, 509, 514

New Boston, 519, 529, S37, 540, 546, 550

519. 564

591

Rutland, Vt., 26

684

INDEX TO VOLUME II.

Rye, ....

Ryegate, Vt., ....

Salem, .... 549,
Salisbury, 519, 527, 531, 564,

Salisbury, Mass.,
Sanbornton, . . 531, 568,
Sandown, ....

Sandwich, 11, 104, 203, 252, 592,

Sanford, Me., 11,
Seabrook, 612,

Sharon, .
Shelburne,
Sherbrooke, P. O.,
Somersworth, .
South Hampton,
South Newmarket,
Springfield, 473,
Springfield, Vt.,
Stark, 12, 52, 62,

616, 626, 630,
623, 625, 632.
24,
54,65

480,498, 515,
372, 400, 408,
63, 69, 78, 90,
228, 259,
• 40,46,77,

Stewartstown, .

St. John, N. B.,

Stoddard, . 468, 472, 490,

Strafford, . . 549,612,

Strafford, Vt., ....

Stratham, ....

Stratford, 52, 62, 69, 70, 74, 80,

Success, . . . . 54, 68
Sullivan, ....

Sunapee, 468, 473, 480, 498, 510,
Surry, 25, 418, 467, 473, 485,

Sutton, .
Swanzey, .

Tamworth ,

. 469, 522,
24, 467, 470,

Page.
626, 633

• 359

561, 631

569, 585

. 632

577, 593

614, 619

597, 600

607

632, 645

633, 638
541, 574
, 75, 202

. 92
620, 642
623, 638

. 640
520, 645
412, 644
200, 209
3^3, 359
317. 368
16, 19
525, 641
620, 642

. 400
632, 640
154, 199
259
, 90, 252
490, 516
515, 519
499, 507
516,642

531, 585
473> 486
501, 638

229, 232,

Temple, 24, 541, 547,
Thetford, Vt.,
Thornton, 102, 131,

Tilton,

Townsend, Mass.,
Troy, . . 24,

Tuftonborough,

252, 261, 597,601
605
577, 579, 620, 638
317, 360,368,384
156, 252, 563, 603
531, 570, 578, 645

• 559, 585
473,494, 501, 512

• 597, 648

Unity, 409, 412, 421, 424, 468, 481, 507

Vernon, Vt., 428,

Vershire, Vt., .
Victory, Vt., .

434, 443, 452, 637

• 317

. . . 67

Warner, 519, 524, 527, 531,

Warren, ....
Warwick, Mass.,
Washington, . 469, 490,
Washington, Vt., .
Waterford, Vt., . 54,65,
Waterville, 99, 103, 151, 155,
226, 228, 235,
Weare, 519, 528, 535, 537,

Weathersfield,Vt., .
Webster, . 519, 528,

Weedon, P. O.,
Wells River, Vt., .
Wentworth, . . 102,

Wentworth's Location,
Westmoreland, 25, 414, 419,
431, 472,
Westminster, Vt., .
Whitefield, 12, 55, 68, jt,^

Wilmot, . . . 469,
Wilton, . . 543, 546,
Winchendon, Mass.,
Winchester, 423, 428, 438,
,486,
Windham,
Windsor,
Windsor, Vt., .
Wolfeborough,
Woodstock, . . 99,
Woodsville,

Page.

563, 571, 585
589, 642

473. 477, 595

519, 523,642
. 401
281, 292, 368
194,203,211
252, 258, 593
575,581, 590
641
365, 398, 404
531, 563, 589

• • 356

373,478, 514
61, 74
422, 425, 427
476, 485, 508
. 411,642
105, 204, 274

518, 522,645
551, 579, 638

• 527
452, 467, 473
501, 519,637

. . 561

• 525
. 403, 645

• 597, 606
102, 131, 564
285, 348, 356

York, Me.,

Trachyte,
Triassic,

Tuckerman's falls, .
" ravine.

Utica slate.

II, 625, 630, 633

. 609

• 21, 445

. . . 183

. 120, 253

14

Veins,
Vose, G. L.

76

152, H

Wakefield,
Walpole, .

410,

549, 598, 602, 647
414,421,425,642

Walker's Staircase, . . 1 01, 159

White Mountain district, geology of 98
" notch, . . 161, 122

" rocks, age of . 264

Winnipiseogee Lake gneiss. (See
Lake gneiss.)

Winnipiseogee lake, . . . 595

ERRA TA.

On page 12 the first entire sentence should be corrected to read thus: The two
united extend only as far as Quebec, as shown upon Plate I, while there is an outlier
upon the peninsula of Gaspe.

On page 20, lines 18, 20, and 22, omit the commas after First, Second, and Third.

On page 32, line 7, for "Upper," read Lower.

On page 126, line 13, for '"branch," read bajik.

On page 134, line 20, for "P. Q.," read P. O.

On page 176, line 28, insert co>?imencing before 700.

On page 200, line 21. for " notch," read station.

On page 204, line 3, for "Waternoo," read Weetamoo.

On page 265, omit the sentence commencing "The Atlantic," in line j6.

On page 287, line 19, for "Fig. 32," read Fig. 31.

On page 302, line 26, for "Mt.," read IVest.

On page 352, line 8, for "Post," read Pout.

On page 408, line 3, for "EAST," read WEST.

On page 426, line 7. for "Fig. 80," read Fig. 81.

On page 444, line 2, for "Fig. 71," read Fig. 72.

On page 507, line 2, for "Grantham," read Grafton.

On page 514. line 8, for "east," read west.

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