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[4] DESCRIPTION

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Pew ih OF NEW JERSEY,

BEING

A FINAL REPORT,

BY

HENRY D. ROGERS,
STATE GEOLOGIST,

PROFESSOR OF GEOLOGY AND MINERALOGY IN THE UNIVERSITY OF PENNSYLVANIA;
MEMBER OF THE AMERICAN PHIL. SOC.; OF THE ACADEMY OF NAT. SCIENCES 5
FELLOW OF THE GEOLOGICAL SOCIETY OF LONDON, ETC.

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GEOLOGY OF NEW JERSEY.

INTRODUCTION.

Tue geological structure of a region being intimately con-
nected with its external physical features, it will usually be found
that a correct view of the latter will materially assist us in under-
standing a detailed description of the former. I therefore propose
introducing my account of the geology of the State of New Jersey
with the following brief sketch of the physical aspect which
characterizes each of the several districts into which it naturally
divides itself.

The State is separated on the northeast from the State of
New York by an artificial boundary line, which commences at
the Hudson river, very near lat. 41°, and extends in a northwest
direction to the Delaware river at Carpenter’s Point, or the
mouth of the Macacomac river: but on every other side it is
enclosed by a natural boundary, namely, by the Delaware river
and its bay, on the northwest, west, and southwest, and by the
waters of the Hudson river, the Raritan bay, and the Atlantic
ocean on the east.

Its extreme length, measured by a line running nearly due
north from Cape May to Carpenter’s Point, is about one hundred
and sixty-four miles,* while its shortest diameter, measuring from
the Delaware river near Bordentown to the Raritan bay near
South Amboy, is about thirty miles.

The area of the State, approximately estimated, is about seven
thousand two hundred and seventy-six square miles. In shape it
bears some resemblance to a bean—its northern half representing
the one lobe, its southern half the other.

* See Gordon’s Gazetteer for New Jersey. ,

4

A slightly undulating line, stretching from the Delaware river
a littie below Trenton to the Raritan river at the mouth of
Lawrence’s Brook below New Brunswick, divides the State into
two regions, which are nearly equal as respects their area, but
which are strongly contrasted if we regard their external physical
features and scenery, their geological structure, mineral produc-
tions, and prevailing soils.

The portion of the State lying south of the Raritan bay and
east of the tidewater portion of the Delaware* and the line above
mentioned, is remarkable for its low, level, and uniform surface.
With the exception of a few isolated hills of humble elevation,
which occur at distant points, chiefly in the northern part of the
region, this extended plain seldom rises higher than about sixty
feet above the sea. It is extensively penetrated, however, by
streams that have a very gentle descent from the summit level of
the region—one half of them running east and directly into the
Atlantic ocean, while the other half pursue a westward course
and empty either into the Delaware river or the Raritan. ‘The
whole surface of this area is extensively undulated by a system
of ravines of denudation, which furnish their drainage to the
numerous streams alluded to. These, in connexion with the
banks of the streams themselves, afford a ready access, to a
moderate depth, to the valuable mineral deposits which expand
widely beneath the surface over large tracts of this section of
the State.

Throughout this entire district the strata are very nearly hori-
zontal, excepting a brown sandstone and a thin limestone, both of
which occur only in a few localities of limited range; the mineral
deposits are generally soft and uncemented masses, consisting of
a series of alternating sands and clays. From the evidence
derived from the organic remains imbedded in the strata of the
southern half of the State, these belong, with very few exceptions,
to the latest period of the secondary formations of our continent.
The exceptions referred to are a few very local and shallow
deposits of a still later tertaary date.

The soil, throughout by far the largest part of this region, is
excessively sandy, and more than three-fourths of the surface is
covered by an almost continuous forest. ‘Towards its north-

* The tide extends as high up as Trenton.

5

western side, however, there prevails a tolerably broad belt of
much more fertile land, extending from the northern half of
Monmouth county, where it is widest, regularly diminishing in
breadth, in a southwest direction, to Salem. Its northwestern
margin ranges parallel with the Delaware river and the railroad
from Bordentown to South Amboy, keeping generally within
from three to six miles of them. This highly favoured tract,
which is denominated the “ Marl Region,” and which will be
minutely described in the following pages, resembles the rest of
the district very closely as to its general topographical features,
but offers a striking contrast in point of agricultural productive-
ness. Its soil, which usually possesses a more or less proportion
of the subjacent “marl” or green sand in its composition—
deriving hence its superiority—belongs principally to the two
varieties denominated by farmers sandy loam and loamy sand.

The northern half of the State, or all that portion of it which
lies north of the line connecting the Delaware and Raritan, at
points respectively a little below Trenton and New Brunswick,
exhibits to the eye of the traveller a scenery wholly different
from that of the more monotonous tracts of the southern division
just described—possessing a surface at once diversified and
picturesque. When we view the several districts included within
this interesting and varied region, whether in reference to their
distinctive physical features, their particular mineral productions
and geological structure, or their characteristic soils, we find the
whole susceptible of a natural subdivision into three well-marked
tracts.

The first of these, or that upon the southeast, comprises nearly
one half of the whole area of the northern half of the State,
which it crosses in a northeast and southwest direction, from the
Delaware river to the New York state line, having a length of
about seventy miles. Its southeastern limit is formed in part by
the line already mentioned as extending from Trenton to New
Brunswick, in part by Staten Island Sound, connecting the
Raritan and New York bays, and in part by the Hudson river.

Its northwestern edge coincides with the base of the range of
hills denominated in New York and in this State, the Highlands.
This boundary follows the foot of the chain from the New York
state line in a southwest direction to the Delaware river, coin-

1*

6

ciding for several miles very nearly with the course of the
Ramapo river; then pursuing, in a gently curving course, the
base of the Pompton Mountain, the Trowbridge Mountain, Mine
Mountain, and the Musconetcong Mountain, until it meets the
Delaware in the vicinity of Durham.

The average width of the district between the two limits here
traced is about twenty miles. Both as respects its geology and
its topographical features, this is one of the best characterized
belts of country in the State. Most of its surface is a moderately
undulating plain, composed almost exclusively of a more or less
argillaceous red sandstone. But this plain is diversified by nume-
rous abrupt and rugged hills, and long and narrow ridges of no
great elevation, but of very steep and rocky sides, consisting of
greenstone trap, which impart to the district much pleasing
scenery, and lend to its geology and mineralogy some highly
curious and interesting peculiarities.

The second division of this part of the State includes the entire
chain of the Highlands, bounded on the southeast by the line
already traced along the base of the Ramapo, Pompton, Trow-
bridge, and Mine Mountains, Fox Hill east of German Valley,
and Musconetcong Mountain, and on the northwest by the north-
western base of the ridges known as the Pochuck Mountain,
Pimple Hill, Furnace Mountain, Jenny Jump Mountain, Scott’s
Mountain, and Marble Mountain at the Delaware.

The belt of hills embraced within the limits here delineated is
widest towards New York, their breadth at the state line being
about twenty-three miles; while a transverse section through
Scott’s and Musconetcong Mountains near the Delaware will
not exceed nine miles.

Though possessing only a moderate elevation, which rarely
exceeds six hundred feet, measured from the adjacent valleys,
they are distinguished by their mountainous aspect, their sides
being usually very rugged and steep, their outlines boldly undu-
lating, and their surface for the most part clothed with forest.
The whole group consists of a series of parallel ridges, composed,
with the exception of a single range—the Green Pond Mountain—
of thickly bedded stratified primary rocks; the prevailing direc-
tion, both of the strata and the ridges which they form, being
about northeast by north and southwest by south. Included
between these ridges occur several long, narrow, and parallel

7

valleys, in which the soil, differing from that of the hills, is fertile
and often highly cultivated. The subjacent rocks of these valleys
is a blue limestone of the ancient secondary date.

The perfect levelness of certain tracts forms a singular and
striking feature in some of these valleys, and in the parts of the
red sandstone region bordering the southeastern base of the
Highlands. ‘These “plains” are in some instances extensive
natural meadows, which are in many cases underlaid by beds of
peat. Among them are the Pompton, Succasunny and Morris
Plains. The substratum of these plains is commonly a deep de-
posit of diluvial gravel.

The third and remaining district, into which the northern half
of the State naturally divides itself, comprising a large part of
the counties of Sussex and Warren, is embraced between the
northwestern base of the Highlands, already traced, and the
Delaware river. A broad and fertile valley, occupying rather
more than three-fourths of this district, and bounded on the south-
east by the base of the Highlands, and on the northwest by the
foot of the Blue and Kittatinny Mountains, extends throughout
its whole length, from the New York state line southwestward
to the Delaware river.

The average width of this comparatively level belt of country,
the proper name of which is the Aittatinny Valley, is between
nine and ten miles, while its length, from the New York line to
the Delaware, is about forty miles. It is drained throughout two-
thirds of its entire length by the Paulinskill, which flows nearly
centrally along it to the Delaware. The other portion next New
York is watered by the Wallkill and its sources. Its surface is
moderately uneven, presenting the aspect of a gently rolling
plain, intersected here and there by abrupt ravines and the
valleys of the streams. It presents many knolls and low ridges,
which become more numerous and elevated as we approach the
base of the Blue Mountain.

Two varieties of rock, /imestone and slate, ranging in several
parallel belts, some of them throughout its entire length, compose
the strata of this valley. The widest zones of the limestone occur
in the southeastern half of the valley, while along the north-
western side a broad belt of the slate extends parallel with the
base of the Blue Mountain. It has many tracts of highly fertile
soil, especially where the limestone underlies the surface.

8

Bordering this valley on the northwest we have the conspi-
cuous mountain ridge known as the Blue Mountain or Kittatinny,
remarkable for the level outline of its summit, the singular
straightness of its course, and its superior elevation, compared
with any of the other hills of the State. The width of the moun-
tain at its base is from one to three miles, varying at different
portions of its length, but being greatest where it traverses the
northern half of Sussex county. Its greatest height appears to
be at the Water Gap of the Delaware river, where it has been
estimated at Fourteen Hundred and Fifty Feet.

The materials composing this mountain are hard sandstone
and conglomerate, imparting to its steep and broken sides, and to
the country immediately at its base, a rough and stony soil, little
congenial to the wants of agriculture. Along its northwestern
base and slope this high ridge is almost every where covered
with forest; but in some portions of its length, especially that
part which lies in Sussex county near the New York line, large
tracts of fertile farms occupy its southeastern flank. This feature,
so unusual to the Kittatinny Mountain throughout its course across
Pennsylvania or New Jersey, and which seems confined to this
part of Sussex and to the adjacent counties of New York, arises
from the circumstance that the soft and tillable slates of the
southeastern base of the mountain rise to a more than usual
height upon its side in these cultivated sections.

The rest of the northern region of the State lying between the
northwestern base of the Blue Mountain and the Delaware river,
is comprised in a narrow valley, the surface of which slopes
gently to the northwest or towards the river. The soil of this
confined belt of country is various, partaking partly of the nature
of the several underlying strata, partly of the materials which
have been swept hither by floods, from the adjoining Blue Moun-
tain and from the more elevated lands of Pennsylvania, lying to
the north and northwest. Jmmediately bordering upon the river
we find a belt of highly fertile land, of diluvial and alluvial origin,
gazing upon which the traveller on the summit of the Blue Moun-
tain may regale his eye with a series of highly pleasing pictures,
embracing a long tract of the richest farms, the meanderings of
the beautiful Delaware, and the picturesque and varied slopes of
the neighbouring ridges.

PART I.

GEOLOGY OF THE NORTHERN DIVISION OF THE STATE, EMBRACING THE
COUNTIES OF SUSSEX, WARREN, HUNTERDON, MORRIS, BERGEN, PAS-
SAIC, ESSEX, SOMERSET, MERCER, AND PART OF MIDDLESEX.

Of the Formations embraced within the Northern Division of the
State.

Tue rocks which constitute the somewhat diversified geology
of the northern half of the State are to be classed in three sepa-
rate groups, readily distinguishable by their different mineralo-
gical characters, the dates of their formation, and the belts of
country to which they severally belong.

Enumerating them in the order of the period of their produc-
tion, they are,

First. A group of primary rocks, confined to the Highlands
and the vicinity of Trenton.

Secondly. A group of older secondary strata, confined to the
northwestern portions of Sussex and Warren counties, from the
base of the Highlands to the Delaware river, and to most of
the regular valleys between the primary ridges of the Highlands.

Thirdly. A group of middle secondary strata, lying in the
broad belt of country between the southeastern foot of the High-
lands and the boundary connecting Trenton and New Brunswick,
including, also, the red shale, red sandstone, and conglomerate
rocks, of the Green Pond Mountain. With the above third group
are connected the trap rocks, which are confined almost exclusively
to the region of the middle secondary formation, just referred to.
We arrive at a knowledge of the relative dates of these several
formations, from the order in which they severally overlap each
other: thus, the lower members of the older secondary or Appa-
lachian series, especially the blue limestone, the second from the

10

bottom of the group, will be found to encircle very extensively
the bottom of the hills, or spurs of the Highlands, and to repose
at a mioderate inclination wnconformably upon the primary rocks
of which these hills are composed. In like manner, both along
the southeastern foot of the Highlands and around the Green
Pond Mountain, the rocks of the middle secondary group are
seen to overlie these /ower secondary or Appalachian rocks with
an unconformable inclination, which plainly establishes the sub-
sequence of their date, by showing that the others had already
been uplifted before these overlapping rocks were deposited upon
them. We behold the trap rocks resting in many instances in
their turn upon the middle secondary strata of their district,
and with such obvious appearances at the line of contact of the
two formations of a disruption and partial fusion of the latter, as
to leave no doubt in the mind of the cbserver, that the former
were poured out through fissures in the middle secondary rocks,
at a period when these had been already deposited, and at least
partially solidified.

The following tabular arrangement of the rocks and strata of
the northern division of the State, specifies the name and nature
of the several formations, and exhibits the order of their succes-
sion from the trap, which is the newest rock of the region, to the
primary strata, which are the oldest.

The Geological Map will render intelligible the range and ex-
tent of each of these formations, while the accompanying Sections
will point out the manner in which they are, severally related in
the order of superposition.

TABLE,

Showing the order of succession of the rocks forming the northern
division of New Jersey.

Trap Rocks.—Generally coarsely crystalline; sometimes fine-
grained and basaltic; they rest unconformably upon the
middle secondary strata, through which they have been pro-
truded.

Middle Secondary Rocks.

1. Variegated calcareous conglomerate. Generally a very
heterogeneous rock, in which a large proportion of the

11

pebbles are limestone, the cement consisting chiefly of red
argillaceous earth.

2. Red argillaceous sandstones and red shales. ‘Towards the
lower part of the formation, contains numerous beds of
coarse gray arenaceous sandstone.

Lower Secondary Rocks.

1. A light blue and gray fossiliferous limestone—the lower
member of formation VIII. of the Appalachian series—ex-
tends between Carpenter’s Point and Wallpack Bend.

2. Red and variously coloured argillaceous shales. Passes
into a heavy compact red sandstone. Occupies the north-
western base of the Blue Mountain.

3. A compact, white and gray sandstone alternating with
massive layers of white quartzose conglomerate—the princi-
pal rock of the Blue Mountain.

4. A dark argillaceous shivery slate, sometimes including
beds of roofing slate. Kittatinny Valley.

5. Blue limestone—presenting great diversity of aspect and
composition—southeast side of the Kittatinny Valley and its
branches.

6. A white quartzose sandstone, somewhat coarse and friable.
Occurs only in a few isolated localities.

Primary Rocks. These are, almost exclusively, of the stratified
class; consisting of gneiss under all its forms—the grani-
toid variety greatly predominating. Innumerable small veins
of felspathic granite, sienite, &c. penetrate the gueiss.

In offering a systematic description of the geological pheno-
mena of a region, we have our choice either to begin with the
deposits of a recent date, referable to easily explained causes,
passing successively to those of more remote eras and obscurer
origin, or to commence our history with the earlier occurrences
of our globe, and trace them in their natural order of succession.

As the latter method seems the one best adapted to our present
object, which is not merely to describe the characteristic geolo-
gical features of the region, but to unfold, in correct chronologi-
cal order, the successive stages through which it has passed in
acquiring its present complicated structure, I shall adopt it in
these pages.

12

The formations will therefore be treated in the ascending order,
as regards their superposition, or in the order of geological time,
as respects the date of their production.

I shall commence with an account of the geology of the
Highlands—these ridges consisting of the oldest or primary for-
mations. : .

CHAPTER I.
Primary Rocks or THE STATE.—GEOLOGY OF THE HIGHLANDS.

Composition and Structure-—The rocks which constitute the
chain of hills to which we give the general name of the High-
lands of New Jersey, are embraced, with a few exceptions, in the
group denominated by geologists the Gneiss System. They are
composed of the same assemblage of materials as the ordinary
varieties of granite, viz. quartz, felspar, mica, and hornblende
(and sometimes augite, magnetic oxide of iron, garnets, &c.), but
differ from the true granites by possessing a stratified structure.

Their strata are, however, very frequently penetrated by veins
and dykes of granite, sienite, greenstone, and other rocks of
unequivocal igneous origin, a circumstance naturally calculated
to lead the inattentive observer to infer that the granitic or unstra-
tified primary rocks form an extensive portion of these hills.
This prevailing misconception is heightened by the granitoid
character of the gneiss, which is seldom comparatively of the
schistose kind, being far more commonly a massive rock in thick
beds, containing relatively few divisional planes. Its analogy to
common granite is still further increased by the relative defi-
ciency of its mica—the usual mixture being either felspar and
quartz, with a little mica, or felspar and quartz alone; or felspar
and quartz and an excess of hornblende; and, not unfrequently,
felspar, quartz, hornblende and magnetic oxide of tron, which in
many places seems to take the place of the mica, giving to the
rock the speckled aspect of a micaceous gneiss. Magnetic oxide
of iron is in fact an abundant, we might almost say a characteristic
constituent in the rocks of this region, for it occurs not merely as

13

an occasional ingredient in the gneiss, but in great dykes or veins
penetrating the strata. It may be stated as a general feature in
the geology of this region, that mica, talc, chlorite and other
laminated minerals of the micaceous order—prominent ingredients
in the more schistose primary strata—rarely prevail to any extent
as regular constituents of* the gneiss rocks of the Highlands.
In this respect this whole primary chain, viewing it from the
Delaware to the Hudson, presents a striking contrast to the other
zone of primary stratified rocks, which traverses the country
nearer to the seaboard with little interruption from New England
to the Southern States. The gneiss rocks of that belt bordering
Long Island Sound, passing through New York and Staten
Island, reappearing at Trenton, and ranging through Pennsyl-
vania and Maryland, are distinguished for the prevalence of mica
and other thinly laminated minerals, imparting to them either the
schistose structure or the more or less thinly-bedded character of
ordinary gneiss.

A common feature in the massive gneiss of the Highlands is,
a tendency to parallelism in the arrangement of its minerals,
especially of the felspar and hornblende. In this case the crystals
are of a flattish form, and are apt to lie in thin and somewhat
separate alternate layers in the rock. This structure seems strictly
in harmony with the doctrine which assumes that the so-called
primary stratified rocks have been once sedimentary deposits,
like the secondary strata, modified into their present crystalline
texture by a heat approaching to a partial fusion of the materials.
The relative absence of mica and of the more thinly laminated
or schistose character, so predominant in some portions of our
southeastern primary belt, has arisen, if this hypothesis, usually
denominated the “ metamorphic theory,” be correct, simply from
a relative deficiency in the original deposits of those earthy mat-
ters, such as clay, lime, magnesia, &c., which are the ingredients
of mica and the minerals most nearly allied to it; or, what is the
same thing, from a relative excess of silica and those other earths
or oxides which are constituents of quartz, felspar, and hornblende.
The influence of a difference of temperature in bringing about a
difference in the mineral aggregation of the various earths, pro-
miscuously mingled at the period of their deposition, is also
possibly connected with the marked contrasts which we see

2

14

prevailing in respect to their composition, between the stratified
primary or metamorphic rocks of different belts of country.

Notwithstanding the innumerable granitic and other veins,
which occur with all the phenomena of violent injection, pene-
trating at small intervals every considerable tract of the gneiss
rocks of the Highlands, these strata are decidedly less contorted
and folded together into those minor flexures so usual among the
micaceous beds of this rock forming the southeastern belt. This
probably arises from the massive character of its strata, and the
absence of the more flexible mineral, the mica.

The strata are usually highly inclined, their average dip
exceeding 45°. In many of the principal mountain ridges an
anticlinal arrangement of the dip is plainly visible. In these
instances the strata on one flank of the mountain, the north-
western, are inclined to the northwest, while on the other they
dip to the southeast.

The common or rather the almost universal direction or strike
of the strata, is from the northeast by north to the southwest
by south. They are only occasionally found to depart from
this direction, which is that of the principal mountain ridges
themselves, and indeed of the entire chain of the Highlands, from
the Hudson to the Delaware.

Geographical Eatent of the Primary Rocks.—The general limits
of the primary region of the Highlands have already been pointed
out in the introductory chapter, when describing the physical
aspect of the northern division of the State. The southeastern
boundary of this belt was there traced as ranging along the base
of the Ramapo, Pompton, Trowbridge, and Mine Mountains;
thence along the base of Fox Hill east of German Valley, and
the foot of Musconetcong Mountain to the Delaware: the north-
western limit was likewise stated to follow the foot of the Pochuck
Mountain, Pimple Hill, Furnace Mountain, Jenny Jump Moun-
tain, Scott’s Mountain, and Marble Mountain, at the Delaware.
Between these two somewhat undulating lines are comprised all
the primary rocks of New Jersey, if we except the small trian-
gular tract of gneiss which enters the State at Trenton, and
which terminates in a point on the Assympink, about six miles
east of that town.

It has been already mentioned, that all the rocks included between

15

the two margins of the extensive belt above traced, do not belong
to the primary class, but that most of the included valleys consist
of an ancient secondary limestone, while the Green Pond Moun-
tain is composed, throughout its whole length, of yet more recent
formations of the middle secondary date.

To convey a more accurate conception of the areas occupied
by the several parallel but somewhat detached belts of primary
strata, which together constitute this broad chain of Highlands,
we would call attention, in the first place, to the manner in which
this whole range of hills is subdivided by several long, narrow
longitudinal valleys.

It will be seen by inspecting the Geological Map, that these
divide the whole chain into two continuous parallel mountain
belts, traversing nearly the entire breadth of the State, and form
also several minor interrupted ridges, skirting the former on the
northwest and southeast.

Delineating severally the limits of these primary ridges, we
begin on the southeast at Mine Mountain. This first tract of the
gneiss rocks includes the whole of the elevated ground which
commences at Morristown with the name of the Morris Moun-
tain, and terminates under the name of Mine Mountain, in
the fork of the north branch of Raritan river and Pepack
Brook.

These primary strata, bounded on the northwest by the lime-
stone and other secondary rocks of Mendham Valley, have their
margin coincident very nearly with the course of the turnpike
from Morristown to the village of Mendham. ‘Thence they are
traceable to the south, following the course of the north branch
of the Raritan as far as its junction with Mine Brook: from this
point they range to the northeastward, parallel with Mine Brook
itself, as far as Vealtown, from which their margin is a somewhat
undulating line, by Mount Kemble back to Morristown. Except
where the short belt of limestone of the Mendham Valley comes
in contact with the gneiss, its border, as here traced, is every
where overlaid by the red shale and sandstone strata of the middle
secondary formation. The general structure of the ridge, as re-
spects the dip and direction of the strata, is such as strongly to
imply the presence of an anticlinal axis traversing it longitudinally
from northeast to southwest, to which, in all probability, its rocks

16

owe their elevation. The next continuous zone of primary strata, is
one of far more extensive area. It is included between the general
northwest boundary of the middle secondary rocks, on the one
hand, and on the other, the long unbroken valley, which com-
mences at Clinton, and extends thence along the south branch
of the Raritan to its source at Drakeville, and by Green Pond,
Macapin Pond, and Long Pond to Dutch Hollow, in the State
of New York. Between these limits its range is uninterrupted
from near Clinton to the State line, or indeed to the Hudson.
To trace this belt of gneiss rocks more exactly, we follow them
from the point where the Ramapo river crosses the State line,
along the northwestern border of the Ramapo Valley to Pompton,
a little north of Ryerson’s. Throughout this distance they are
overlaid by the middle secondary, red shale, and sandstone
group. In the neighbourhood of Ryerson’s, a caleareous conglo-
merate, which when present is the uppermost stratum of that
group, lies nearest to the gneiss; the immediate boundary of
which, however, is very commonly concealed along the base of
the hills, by a deep covering of diluvial gravel. From Pompton,
in contact for a part of the space with the diluvial matter which
composes the substratum of the Pompton Plains, the gneiss rocks
take their course along the foot of the Pompton Mountain by Mont-
ville and Boonton Falls, and thence along the base of the Trow-
bridge Mountain to near Mendham.

As far as this latter point, the overlapping rocks are the upper
beds of the middle secondary formation. In the Mendham Valley,
the gneiss comes in contact, for a distance of a few miles, as far
as Pepack, with the blue limestone of the Appalachian or lower
secondary series. From Pepack the formation extends still to
the southwest, passing about a mile to the north of New German-
town, and thence in a more westward direction to a point nearly.
north from Lebanon and two miles northeast of Clinton, where it
meets the limestone of the valley of the South Branch. Between
Pepack and a point nearly north from Lebanon, the gneiss is, with
some few interruptions, in contact with the calcareous conglo-
merate, the uppermost stratum of the middle secondary rocks.
Sweeping round to the north, and afterwards to the northeast,
the margin of the gneiss thence pursues the southeastern side of
the valley of the South Branch, or German Valley, in contact

17

with the older secondary limestone, as far as a point about two
miles south of Flanders. From hence, along the same side of
the same topographical valley, it is marked by the overlapping
diluvial matter of the Succasunny Plains. Beyond the ter-
mination of these plains, northeast of the village of Succasunny,
the primary rocks, pursuing still the southeastern edge of the
same valley prolonged, come in contact with the middle secondary
strata of the Green Pond and Copperas Mountain, as far as the
Pequannock. Northeast of this stream, for a range of several
miles, they disappear beneath the older secondary limestone of
the Macapin Pond. Beyond this limestone to the State line,
they come again in contact with the red sandstone beds of the
Copperas Mountain, here called the Long Pond Mountain. This
part of the boundary is marked by the southeastern side of the
valley of Belcher’s creek, nearly to Long Pond.

Another axis or elevated belt of the primary rocks, still more
extensive than that just described, as respects length, lies imme-
diately to its northwest, separated only by the long line of vailey
already traced. The southeastern margin of this latter tract of
the gneiss coincides from the State line to the Pequannock, in
some places with the red sandstone strata of the Long Pond Moun-
tain, and in some places with the slate and limestone formations
of the older secondary group, while in other neighbourhoods, it
is separated from these by a narrow strip of diluvium, forming
the bed of the intervening valley. From the Pequannock south-
ward to Flanders, it ranges at an average distance of half a mile
from the northwestern base of the Green Pond Mountain, its imme-
diate boundary being the diluvium of the Longwood and Berk-
shire Valley and their prolongation.

Thus covered, the edge of the gneiss passes Drakeville and
Flanders, until, beyond the latter place, it encounters the older
secondary limestone of German Valley. It thence extends down
along the northwestern side of this valley to its outlet north of
Clinton, the limestone every where forming the overlapping stra-
tum. From the neighbourhood of Clinton, its course is first nearly
westward to the vicinity of Vansickle’s, and thence southwestward,
following the base of the Musconetcong Mountain to the Dela-
ware. Between the South Branch, north of Clinton and the head

of Milford creek, the gneiss rocks dip beneath the ancient lime-
D*

18

stone; but from the latter point to where they strike the Dela-
ware, they are overlaid, throughout the chief part of their course,
by the calcareous conglomerate, which caps the middle secondary
series.

The northwestern margin of this same chain of the gneiss, is
marked by the edge of the Musconetcong Valley, and sometimes
by the border of that stream itself, along the entire distance be-
tween its outlet at the Delaware and the head of the valley, near
the old Andover Forge, the primary strata every where descend-
ing beneath the older secondary limestone. From the old Ando-
ver Forge, it follows nearly the brink of Musconetcong creek
by Stanhope to Brookland, at the outlet of the Hopatcong Pond,
being generally, except at Stanhope, in contact with the limestone.
It there folds round the base of a hill west of the Pond, which it
pursues, passing a little east of Columbia Forge and the villages
of Sparta, Ogdensburg, Hamburg, and Vernon, to New Milford,
at the State line. In all this part of its somewhat undulating
course, the gneiss dips beneath the overlapping edge of the older
secondary limestone.

The mountain belt of which the boundary has here been traced,
consists essentially of a single uninterrupted belt of axes of
elevation, giving to it a general anticlinal structure. It receives,
nevertheless, several distinct appellations, applied to different por-
tions of it. Between the sources of the Pequannock and the deep
transverse gorge which almost intersects the chain at Drakesville,
it takes the title of the Hamburg or Wallkill Mountain. From
the cross valley above mentioned to that of Spruce Run, it bears
the name of Schooley’s Mountain, while between the latter limit
and the Delaware river, it is called the Musconetcong Mountain.

To the northwest of the great continuous belt of primary hills,
whose boundaries have just been traced, there rises a chain of
rather less elevated scattered ridges, which occupy insulated
tracts in what, if we take a comprehensive view of the topogra-
phy of the region, ought to be regarded as the southeastern por-
tion of the Kittatinny Valley. These hills are surrounded on all
sides by the older secondary limestone of that valley, through
which at least some of them seem to have been protruded sub-
sequently to the period of deposition of the limestone over the
gneiss. ‘Though they do not constitute a strictly connected range

19

of the formation, they evidently compose, like the chain to the
southeast, one general belt of axes of elevation, inasmuch as they
all lie within a narrow zone and nearly in the prolongation of
each other. The limestone which encircles them, usually dips
from their flanks, apparently in consequence of an upheaving action
near a central line traversing each hill longitudinally.

Proceeding with our detailed delineation of the boundaries of
these primary tracts, we first meet, towards the northeast, the
Pochuck Mountain. This ridge, in which the gneiss has evidently
an anticlinal arrangement, though a somewhat irregular one, com-
mences in New York, about a mile northeast of the State line,
and terminates near the village of Hamburg, having a length of
about eight miles, and a breadth ranging between one and two
miles.

At its southeastern base, the primary rocks disappear beneath
the limestone of the Hamburg, or Black Creek Valley; while
along the northwestern side they are overlapped by the same
formation, a little east of the Meadows of the Wallkill. This
ridge is interesting from its having, towards its southwest termi-
nation, a valuable deposit of brown hematitic iron ore, to be here-
after described.

The next ridge of importance is Pimple Hill, which, together
with a spur which it throws off towards Sparta, extends from
near that place to Franklin. On the southeast flank of this
ridge of primary, is the much celebrated Sterling Mine, consist-
ing of zinc ore and Franklinite.

From Sparta there extends, towards the southwest, another
elongated narrow belt of the primary to within a mile and a half
of Andover village, while, about a mile to the northwest of this
belt, which is bounded by the limestone of a highly crystalline
and altered aspect, there lies a small oval hill of the gneiss, also
similarly encompassed. Next, in our progress to the southwest,
we encounter two other low and detached hills of the primary, both
of them lying a little east of the turnpike which joins Stanhope
and Andover.. Immediately west of this road, we meet with a
larger tract of the primary, which extends continuously almost
to the road which unites the villages of Hacketstown and Vienna.
Its southeastern boundary passes Lockwood and the old Andover
Forge, thence along the western side of the Hacketstown Valley

20

to near the road last mentioned, its northwestern margin passing
by Alamuche.

From the vicinity of Hacketstown to near Mount Bethel Meet-
ing-house, there ranges another low ridge of the gneiss, having a
length of about four miles and an average breadth of one. Rest-
ing upon the primary strata of this tract, is a small patch of
nearly white sandstone, well adapted for purposes of architec-
ture, for which it has been occasionally used. This is one of a
few isolated patches of the lowermust rock of the older secondary
or Appalachian series, in New Jersey; a formation displayed so
extensively in contact with the primary rocks of the same general
chain, both in New York and Pennsylvania. Another locality
of the sandstone is to be found between Flanders and Succasunny,
northeast of the former village; and two other exposures, are visi-
ble near Macapin Pond, where the rock is in contact with the
overlying blue limestone.

Another considerable surface of the gneiss extends from near
the village of Mansfield southwestward to the Easton turnpike,
a little west of Bloomsburg; bounded on the northwest by the
Pohatcong stream, and on the southwest by the valley of the
Musconetcong.

The next important belt of primary rocks is that of the moun-
tain called Jenny Jump. ‘This ridge, extending from near the
outlet of Bear Brook at the Great Meadows, almost to the village
of Sarepta, is about seven and a half miles long, by about one in
mean breadth.

Its rocks are every where overlapped around its base by the
ancient secondary limestone; an interesting zone of which, in a
highly crystalline and altered condition, ranges along its south-
eastern foot for nearly its whole length.

Two small patches of the primary rocks, which seem to have
been exposed by denudation of the limestone, occur in the valley
of the Pequest, between that stream and the foot of Jenny Jump.

South of the Pequest rises the conspicuous ridge of primary
rocks, called Scott’s Mountain. Its Jength is about twelve miles,
while its general breadth somewhat exceeds three. Encom-
passed at its base by the limestone, the southeastern limit of the
gneiss ranges parallel for several miles with the Pohatcong
stream, and afterwards with the Morris canal; while, on the

21

north, the valley of the Pequest is the boundary as far as Bridge-
ville. On the northwest, the margin is pretty nearly marked by
the road uniting this place and Oxford. It extends thence through
the spot called Concord to Harmony Church.

The last belt of the primary strata to be traced is that of
Marble Mountain, at the Delaware: this is also surrounded by
the limestone, but its western base is almost washed by the Dela-
ware river. It terminates towards the southwest near Phillips-
burg, opposite Easton; and towards the northeast almost unites
with Scott’s Mountain, near Harmony Meeting-house. Its length
is about four miles, and its average breadth one mile.

Of the Igneous Rocks and Metalliferous Veins of the Fnghlands.
—The metalliferous veins of the primary region of the State,
though extremely numerous and widely distributed, embrace but
few varieties. As regards their general structure, they are all,
in fact, very nearly alike; while the only ores they comprehend
in large amount belong to the two metals, iron and zinc; those
of iron being by far the most abundant.

Structure of the Veins.—In their form they are unequivocally
genuine lodes or veins, and often of considerable longitudinal
extent coinciding with occasional slight deviations, with the
direction of the strata which include them. Their position is
usually between walls of the granitoid gneiss, to which they are
parallel, not only in strike, but in dip. They exhibit, however,
many minor irregularities, such as frequent changes in thickness,
suddenly bulging to great width, and rapidly thinning out to
almost imperceptible dimensions. This observation is to be re-
ceived as applying with fullest force to the whole body of injected
matter, regarding it as one vein, which it truly is; while the dis-
tribution of the ore within the vein is liable to even greater irre-
gularities. Viewing these veins comprehensively, they consist
not exclusively of the metalliferous ore, whatever it may be, but
of the ore and other minerals, particularly hornblende and felspar,
in one general injected mass. In some instances, the ore consti-
tutes the body of the vein, resting in contact with the gneiss rock
of the walls; in others, it occupies only a part of the thickness
of the mass, being bounded on either one or both of its sides by
the non-metalliferous minerals, usually termed the gangue; while
in other cases again, the vein of ore is split by a wedge of the

22

same gangue, which either entirely cuts it off on one side, or
being of limited length, soon permits the reunion of the divided
portions.

Not unfrequently this gangue comprises the chief width of the
vein, and the ore included in it lies in detached elongated bodies
of lenticular form, having their longer axes always in the direc-
tion of the course of the vein. ‘These insulated masses of the
ore, denominated pots or pools by the miners, are sometimes
more than a hundred feet in length, their thickness varying in
certain large veins from five to forty feet.

Another feature, deranging occasionally the uniformity of
these veins, presents itself, when detached portions or splinters, as
we may regard them, from the adjoining strata constituting the
walls, are found lodged in the substance of the lode. ‘These and
other smaller wedge-shaped masses, interrupting or dividing the
vein, are commonly entitled horses by the miners.

In addition to these irregularities in the distribution of the ore,
we sometimes find the entire vein cut through by faults crossing
it, commonly almost at right angles, and totally interrupting its
continuity.

The several circumstances here spoken of in the structure of
these metalliferous veins, seem strongly to imply that they are real
veins of injection, and not true beds, contemporaneous with the
adjoining gneiss, as some have supposed. A common thickness
of the metalliferous veins under description is from six to twelve
feet; in their inclination or pitch they are quite various, some
dipping, with the strata that enclose them, at as low an angle
as 50°, while many are nearly vertical. In the shallower exca-
vations the workings are open to the sky, and the deepest
shaft yet sunk, that of the Mount Pleasant Mine, near Dover, in
Morris county, is only about two hundred and twelve feet below
the surface.

Nature of the Ore-—The ore belongs to the species denominated
by mineralogists ovidulated iron or magnetic won ore, and is of
two varieties—compact and granular. In its purest form, this
mineral consists of two atomic proportions of the peroxide of
iron, and one of the protoride, which is equivalent to nearly
72 per cent. of the former, and a little more than 28 per cent. of
the latter—yielding about 72 per cent. of metallic iron. In the

23

state in which it is more usually met with, however, mingled
with a greater or less proportion of extraneous mineral matter,
the amount of metallic iron contained ranges between 60 and
72 per cent. It is magnetic, being endowed with the property of
attracting soft iron, and affecting the magnet. Masses of it are
frequently met with possessing a distinct magnetic polarity, the
opposite ends manifesting a repulsive action upon the corre-
sponding ends of the needle. Such specimens are termed
loadstones.

Though the pure variety is often massive, and mingled with
but little foreign mineral matter, yet this is really less productive
in the manufacture of iron than the granular or imperfectly
crystalline kind, in which we find a moderate proportion of
small crystals of hornblende, felspar, quartz, and other minerals,
interspersed with the ore. Some of the ore contains a small
proportion of titanium. ‘The veins often exhibit a tendency to
cleave by numerous natural joints, extending across from one
wall towards the other; a structure which suggests a strong
analogy to the horizontal colamnar arrangement seen in many
vertical dykes of lava and basalt. This, if the proofs already
cited were not enough, deserves to be regarded as an argument
in behalf of the opinion that these veins of ore have been injected,
while in a fused or molten state, into the gneiss, and are not in
the strict sense beds formed contemporaneously with the surround-
ing rock.

This point, though at first sight unimportant, and seemingly
one of mere theory, is of much practical moment to the miner,
since it acquaints him with the nature of the veins in which he is
operating.

Local Details—In offering a detailed description of the veins
of magnetic iron ore as far as they have been developed, we
shall begin, for the sake of convenience, with those lying towards
the northeast. ‘The first which claim our attention are those of
Pompton township, in Bergen county. The principal veins of
this tract occur in the continuation of the Sterling Mountain of
New York. In the ridges immediately west of the Ringwood
Valley at least two extensive veins are known.

The most southeastern of these has been explored for much the
greatest distance, several mining excavations having been made

24

in it, throughout a length of nearly three miles. That to the
northwest is distant from the former about two hundred feet,
and, where it has been traced or mined, has been found to pre-
serve a parallel direction with it. The first mentioned of these
veins extends to within a quarter of a mile of the New York line.
Their course is north northeast and south southwest. The rock
of this region, containing these veins, is the ordinary granitoid
gneiss, abounding in hornblende, and nearly destitute of mica.
It has a steep dip to the southeast.

Following the most southeastern of these two veins, from the
southwest to the northeast, the first considerable excavation
which displays its structure is an old mine, quarried open to the
day, to the depth of perhaps forty feet, and for about three hun-
dred and fifty feet along the vein. The pitch of the vein at this
point is nearly vertical. Its general regularity is somewhat
disturbed by trivial slides and sudden changes of dip. Large
wedge-shaped masses of the gneiss rock of the walls intrude
themselves into the middle of the ore, subdividing the veins into
two or more branches, which send off parallel filaments, that
either dwindle out entirely in the rock, or reunite with the main
body of the vein.

The mean thickness of the ore in this mine is about ten or
twelve feet, exclusive of these interposed masses of rock. Though
not at present used, the ore is stated to be of average purity.

About one hundred feet to the northeast of this is the mine
known as the Blue Mine, from the bluish hue of the ore. The
excavation from which the ore has been removed, is about one
hundred feet in length by fifty feet in depth, while the width of
the vein varies from six to fifteen feet.

At this place also the vein is divided in the middle of the ore
by a vertical wedge of rock, which increases from one to five
feet in thickness, and consists on the one side of red felspar, like
the adjacent wall of the vein, and on the other of compact green
sahlite. In this part of the vein are several oblique dislocations
or slides, always declining to the southeast.

Within less than half a mile to the northeast of this last open-
ing there is another point where excavations have been made,
called the Mule Mine. The principal vein of ore here is seven
or eight feet thick, swelling out at some spots to twenty feet.

25

Formerly it was extensively wrought, open to the sky, to a depth
of seventy feet, and length of one hundred yards. Within only a
few paces to the southeast of this opening, which is called the
Blue Hole, is another in a more circumscribed vein, of a len-
ticular form, called the Mule Ore. This shorter vein is divided
through its middle by a wedge or horse, consisting principally
of massive crystallized hornblende.

Exclusive of this intruded mass, the vein, at its widest place,
where it is at present worked, is twenty-five feet in thickness.
At a somewhat greater distance, on the opposite or northwest
side of the principal vein, occur three or more similar detached
small veins, or, as we ought, perhaps, more properly to say, lenti-
cular portions of the general vein. One of these pots or pools
of ore, denominated the Henion Mine, is about fifty feet in length
by ten feet in thickness. It has been wrought to a considerable
extent, yielding an ore of excellent quality.

The ore of this and some of the other small subordinate veins
possesses the magnetic character in a distinguishing degree.

The whole of the ore of this immediate vicinity of the Mule
Mine is stated to make a good iron, which is apt, however, to be
red short, or brittle, at a red heat.

The pitch of the principal vein of ore of the Mule Mine is
parallel to the dip of the adjoining gneiss rock, which is to the
southeast at an angle of about 60°.

Northwest of these several workings of the Mule Mine, and
higher up the hill, we meet with another set of short, lenticular
outbursts of the ore, wrought by the name of the Cannon Mine.

The greatest width of the ore in the main excavation here is
forty feet, caused, however, by the coalescing at this point of two
adjoining masses, which are elsewhere separated by wedges or
horses of the gneiss rock. The largest of these divisions of the
vein is fifteen feet across. Another somewhat oval mass, lying
almost. in the prolongation of the one here mentioned, and only
separated from it by an intervening wall of gneiss a few feet
thick, has furnished at its widest part a nearly solid body of ore,
thirty feet in thickness.

These ores smelt with facility, but produce a highly brittle, or
cold short, iron.

Beyond these excavations, to the northeast, succeeds the

3

26

Peter’s Mine, formerly worked, partly in a shaft, partly in a
quarry open to the sky.

At this place the dip, both of the vein and the primary strata
bounding it, is at an angle of about 60° to the southeast. The
rock above the ore is a mixture of felspar and mica in a state of
disintegration; in other places it consists of a fine pinkish felspar
rock in the same rotten condition. The form of the vein at the
place where it has been worked, is that of a narrow wall of ore,
six feet in thickness, which presently swells into a huge mass of
an oval form, fifty feet in diameter. This pool of ore has been
wrought beneath the open air to a depth of about seventy feet,
the water being drained off by an adit cut through the adjoining
wall of gneiss.

This ore is said to yield an iron which is brittle at a red heat,
or red short.

The Spanish Hope and Good Hope mines form the next group
of openings as we proceed to the northeast. ‘They occupy the
southwestern extremity of a spur of the main mountain, and occur
at a distance of not more than one-third of a mile from the New
York state line.

The hill in which these mines lie is very rugged, and the ordi-
nary gneiss rock composing it much disturbed, connected with a
considerable degree of irregularity in the metalliferous veins.
The general width of the main body of ore is about eight feet,
dipping with the strata to the southeast at an average inclination
of 70°. The most northwestern of these openings, called the
Good Hope Mine, exhibits the vein in considerable regularity,
dipping at an angle of about 80° to the southeast, and having
a pretty uniform width of nearly twelve feet. These mines were
somewhat extensively worked by an English company before the
revolutionary war: the Good Hope Mine now showing a large
excavation, sixty feet in depth. The ore proved of superior qua-
lity, which led, about twenty years ago, to a resumption of mining
operations, which have been since abandoned.

In the same prolongation, towards the north-northeast, we
find a continuation of this series of mines for several miles into
the State of New York, but whether these occur upon the same
line of veins, seems to be not quite established.

Reviewing in their general connexion the whole line of veins

27

of iron ore here described, we are forcibly impressed with the
belief, that while they are of a moderate length, taken individually,
they are to be regarded as constituting but one long and exten-
sive belt of closely connected metalliferous injections, contempo-
raneously produced.

It appears from what has been detailed, that the ore in its
course to the north grows more uniform and undisturbed. The
general quality of the ore along much of the line here traced is
excellent, answering well for the bloomery or the furnace. Much
of it is coarsely granular, which is a good feature; a portion, how-
ever, is too compact—being somewhat refractory and red short—
especially a particular band or subdivision of the vein.

Near the openings first mentioned, the second or northwestern
vein has been penetrated throughout a length of about one hun-
dred feet, and to a depth not exceeding thirty. Its ore makes an
iron highly cold short, a circumstance which has caused the vein
to be less explored than the other, though it is probable that it
ranges over a considerable distance. Its position is parallel to
the first. The dip is to the southeast, and its width about ten
feet. The ore in these veins is highly magnetic, some of it pos-
sessing magnetic polarity. It is a coincidence which deserves
at least to be alluded to, that in another even richer locality of
magnetic iron ore, namely, that of Mount Pleasant and Succa-
sunny, in Morris county, there exist two extensive veins or series
of veins, the predominant character of the western vein in that
neighbourhood being just as at Ringwood, that of producing a
cold short iron.

About midway between Ringwood and Pompton, or six miles
from each place, a vein occurs in a similar position to the above,
on the west side of the Ringwood Valley, having exactly the
same bearing, namely, north-northeast.

Westward of the iron range here laid down, there would appear
to occur between this and the vein of Franklinite and zinc of the
valley beyond the Wallkill Mountain, more than one considera-
ble and valuable vein of magnetic ore. We may mention the
veins of Charlottesburg and those of the Wallkill Mountain, four
miles east of Franklin Furnace, as examples.

The next district in the primary region, remarkable for an
abundance of magnetic iron ore, is a range of country extending

28

between the Pequannock and Succasunny, running from the
northeast to the southwest, parallel with the Copperas Mountain,
at a distance from it of between two and three miles. The rock
of this region is the usual granitoid gneiss, consisting principally
of felspar and hornblende. The strike of the strata here, as almost
every where else, is to the south-southwest, the usual direction
of the dip being towards the south-southeast, and at high angles,
commonly exceeding 60°.

A series of parallel veins, or more properly speaking, of paral-
lel belts of closely contiguous veins, consisting of very excellent
magnetic iron ore, imparts especial interest to this range.

I shall allude more particularly to three of these belts cf ore, -
conspicuous for their length and well-developed features. Though
the excavations yet made are not sufficiently numerous to esta-
blish satisfactorily either the independence or the strict continuity
of the several portions of a vein or veins occupying the same
line of bearing, yet the indications are, that the individual veins
are of considerable length, say several furlongs, but by no means
prolonged over the whole district.

I incline to view each supposed long vein as made up in fact
of a string of several veins very nearly in a line, one commencing
either at or a little before the termination of another.

As the question of their strict continuity is one of little practical
importance, we may venture, for the sake of present convenience,
to designate them as three great veins, inasmuch as they lie in
three separate parallel zones. [rom a little to the northeast of
Hibernia, where the larger exposures of the ore commence, to a
point at some distance southwest of Succasunny, where they at
present cease, the space over which these belts of the magnetic
ore have been worked, is upwards of ten miles.

The inclination and strike of the several veins coincide, when-
ever they are at all regular, with that of the enclosing strata of
gneiss. Their direction is from north-northeast to south-south-
west.

Commencing with the southeasternmost line of ore at present
developed, we find upon it the two mines, entitled Muir’s Mine,
and Sweed’s Mine. The next parallel belt towards the northwest
embraces the Hibernia Mine, Jackson’s Mine, and Dickerson’s
Mine, near Succasunny. The third range includes the Denmark

29

Mine, where no large vein of pure ore has yet been discovered ;
the Mount Hope Blue Mine, Mount Hope Mine, Teabo Mine,
Mount Pleasant Mine, Harvey’s Mine, Sterling Mine, and Bur-
well Mine. These several mines are here designated in the
order in which they occur, passing from northeast to southwest.
It is not intended to convey the impression that the above classi-
fication into three belts of veins is regarded as positively accu-
rate, for the distances between the excavations, especially along
the two first ranges, are so very considerable, as to suggest a rea-
sonable doubt whether we might not refer them to a greater
number of parallel belts.

Describing the mines in the order above given, we find the most
northeastern of the southeastern range, to be the excavation called
Muir’s Mine. This is about a mile and a half to the northwest
of Rockaway. ‘The vein at the surface of the ground, where it
is occasionally exposed, is six inches thick, widening as it de-
scends, and becoming two and a half feet thick at the depth of
thirty feet. The adjoining rock is a compact gneiss, dipping
parallel with the vein, which inclines at an angle of 45° or 50°
to the southeast.

At a considerable distance to the southwest of the above is
Sweed’s Mine, situated about midway between Rockaway and
Dover. Here the general features are the same, the dip being
50° to the southeast.

The thickness of the vein of solid ore varies from five to twelve
feet. Next to the hanging or overlying wall, there is usually a
band, of about three feet in thickness, of excellent compact ore ;
“beneath this succeeds four feet of spar, consisting largely of
vitreous felspar, and under this again occurs a very poor ore,
mingled largely with the extraneous mineral matter of the foot-
wall or floor, from which the vein is not clearly separable. The
separation between the vein and the hanging wall, on the con-
trary, is well defined. The upper division of the vein is soft and
of a granular structure, and yields a good iron. The impurer
portion next the foot-wall affords, on the contrary, an iron cha-
racterized as red short. It is worthy of remark, that the adven-
tilious matter in the red short ore, is not different from that in the
ore of standard goodness. The ore in the vein is thrown into
some irregularity by wedges or horses of a species of rock,

3*

30

composed apparently of the injected gangue of the ore, consisting
of hornblende or blackjack and mica, with a variable proportion
of ore in an irregular crystalline or granular form. The mine is
drained by an adit which passes out through the side of the hill
next the east.

Upon the second or middle range of mines, the most north-
eastern excavation is the Hibernia Mine. The situation of this
mine, which is upon the top of an elevated hill, adjacent to the
Hibernia Forge, renders it somewhat difficult of access. The
ore here also sometimes shows itself upon the surface, though it
more frequently requires an excavation of moderate depth before
it can be reached.

The dimensions of the vein are quité variable, though its
average thickness is perhaps about eight or nine feet. ‘The ore,
containing much foreign mineral matter, and being at the same
time highly magnetic, affords an opportunity for using the mag-
netic separating machine, by which it is economically freed from
its impurities.

About half a mile to the west of Dover is Jackson’s Mine,
yielding an ore similar to the last. This is inferred, by its
position, to lie upon the same vein or string of veins.

The vein is here seven feet in width. There is a shaft leading
down to the ore forty feet deep. The excavation is about two
hundred feet in length.

The next, and by far the largest vein of the range, is half a
rnile further towards the southwest, at General Dickerson’s, near
Succasunny. Here the enclosing rock is a variety of gneiss,
composed chiefly of quartz and felspar, with occasionally a little
mica and oxidulated or magnetic iron ore, disseminated through
it. The dip is about 60° to the southeast. The mine has been
wrought to a depth of about eighty feet. In the horizontal drift,
along which the vein has been chiefly worked, the quantity
removed has been very great. Here the average thickness may
be stated at about twelve feet, though near the entrance of the
mine, in consequence of an irregularity, the mass of ore seems to
have been at least thirty feet across. This being in a disturbed
portion of the vein, the presumption is, that it does not continue
far of this dimension.

The general structure of this ore is highly granular, showing a

31

frequent approach to the octohedron, the regular crystalline form
of this species of iron ore. It is also sometimes of the compact
variety. It is considered equal to any in the State for the quality
of the iron which it produces. The same vein is said to have
been opened still further to the southwest, but the remotest point
in that direction to which it may be traced has not been ascer-
tained.

Three varieties of the ore occur at the Succasunny Mine—a
blue ore, a reddish ore, and a sparry ore. The first lies next to
the foot-wall, the red ore occurring adjacent to the hanging
wall, while the sparry ore runs generally in separate veins
between the rest of the vein and the hanging wall. One vein of
this variety, measuring twenty-two inches in thickness, is divided
from the other part of the ore by only about three or four inches
of rocky matter.

The price of the blue and red ores at the mine is $3.50 per ton ;
that of the sparry ore, somewhat less rich in iron, is $2.50. The
mine is not very actively worked; about fifteen hundred tons
per annum having been mined during the last five years.

Entering in the next place upon the third or northwestern
belt of veins, we commence, towards the northeast, with the
unimportant excavations near the old Denmark Forge, which
are to be regarded as openings in search of ore rather than a
regular mine. The first mine of consequence in this series is the
Mount Hope Blue Mine, now no longer wrought, occurring ata
distance of nearly four miles to the sonia of the ewe
openings. The vein seems to average from twelve to fourteen
feet in thickness. At the surface of the ground the vein was
from eighteen to twenty feet thick. It has been worked to a
depth of one hundred feet, being, at the deeper portions, as much
as twenty-four feet in thickness.

The excavations consist of a series of inclined galleries, at a
slope of about 25°, in descending zigzag arrangement. ‘The ore
has been removed throughout a length of several hundred feet.
The mine has been abandoned in consequence of the too rapid
accumulation of water. An adit, carried into the mine from near
the base of the hill, would seem to be ail that is required to give
access once more to this large mass of ore.

The next mine, in our progress to the southwest, is the

32

Mount Hope Mine, about a quarter of a mile from the former,
and upon the same line of metalliferous injections. Its position is
upon the northeastern brow of a hill, about three hundred feet in
elevation, overlooking the old Mount Hope Furnace. The quality
of the ore appears to be analogous to that of the Mount Hope
Blue Mine. The thickness of the vein varies, being only one foot
at the south end of the mine, and six feet at the north end.
A shaft has been sunk here between seventy and eighty feet in
depth. ‘This mine is now in operation.

About one-fourth of a mile to the southwest of the last occurs
the Teabo Mine, on the southwestern declivity of the same hill.
Here the vein of ore is almost ten feet in thickness, holding a
nearly vertical position, its inclination being towards the south-
east. The walls are regular and unbroken, consisting of a
rather micaceous gneiss. This is one of the veins in which the
horizontal columnar structure of the ore is very obviously dis-
played. A wedge of rock separates the vein in one or two
places, but only for a short distance. The ore is of excel-
lent quality, though compact, the foreign matter mingled with
the magnetic oxide of iron consisting of a green hornblende and
some quartz. ‘The mine is about one hundred feet in depth, the
length of the excavation exceeding one hundred and fifty feet.

Upon the same supposed northwestern vein or belt of ore, and
one mile further to the southwest, is the Mount Pleasant Mine.
The average thickness of the vein may be given at about eight
feet, though it is very variable, changing from eighteen inches to
twelve feet, and sometimes thinning away, for a short space,
almost to nothing. ‘These fluctuations of width take place as
well in the vertical as in the horizontal direction. The rock
immediately adjacent to the ore, from all appearance protruded
contemporaneously with if, is an almost pure hornblende,
having an extremely beautiful massive crystallization. ‘The ma-
terial of the regular wall, on the one side, is a hard, light-
coloured felspathic rock, while that of the other, or hanging
wall, is chloritic and often micaceous. In driving to the south-
west in one of the galleries of this mine, the progress of the vein
was suddenly arrested by a cross dike of quartz rock, fourteen
feet in thickness. After many fruitless borings for the recovery
of the vein, it was discovered, heaved to the southeast, many feet

33

out of its original line. Beyond the dike the vein is tossed about
in very considerable confusion, the masses of ore occurring
rather in detached pools than in one continuous lode.

The dip of the regular portion of the vein is to the southeast.
The depth to which the mine has been wrought is two hundred
and twelve feet. Lying below the surrounding streams, its
drainage is effected by machinery; a series of well-contrived
pumps, driven by a small brook acting on a water-wheel, being
employed for the purpose.

Nearly a mile and a half west of Dover we find the Harvey
Mine, once extensively wrought by a shaft, but now no longer in
operation. The ore here resembles that of the Mount Hope Mine,
lying in a vein which varies from four to nine feet in thickness.

About three-fourths of a mile west of Dover occurs the Ster-
ling Mine, not at present wrought. ‘The vein of ore was found
to vary from two to thirteen feet in thickness. At one spot, at
twenty feet from the surface, it was only eighteen inches wide,
but grew l&rger lower down. The walls consist of a hard dark-
coloured granitoid gneiss. Several shafts were sunk upon this
vein; the deepest, however, did not exceed thirty-five feet.

The last in this series of mines lies about half a mile south-
westward from the Sterling Mine, and is known as the Burwell
Mine. The vein of ore is about eight feet wide. Two shafts
have been sunk upon it.

Not far from Mount Pleasant, there is a small mine upon a vein
which is supposed to lie to the southeast of those above traced.
_ But little is known of the length or course of this vein, any further
than that its direction and dip are parallel with those of the
others.

A similar vein is known, and has been mined to a considerable
extent, near Powerville; and no doubt many more exist in the
district, though nothing has been done to develope them, and no
useful facts concerning them have come to light. It should be
mentioned that the long range of ore veins above traced, lies
almost exactly in the bearing of the vein near the old Charlottes-
burg Furnace, on the Pequannock.

But few indications of iron ore have been hitherto discovered
in the southwestern prolongation of this first or southeastern

34

chain of the Highlands, in that part of it which is called the
Chester Mountain.

Adverting in the next place to the metalliferous veins of the
other great parallel range of primary hills, which includes in one
continuous chain the Wallkill, Schooley’s, and Musconetcong
Mountains, we are forcibly struck with the fact of their relative
fewness, when compared with the numerous and extensive in-
jections which traverse the more southeastern belt, above de-
scribed.

Upon the Walkill or Hamburg Mountain magnetic iron ore
may be occasionally met with in the soil, while excavations made
at various spots have also brought to light small bodies of the ore,
but no veins of considerable magnitude. ,

Advancing along this chain towards the southwest, we meet
with similar indications of ore in the neighbourhood of Stanhope,
and also south of this, in the vicinity of Flanders, where many
loose fragments of it occur in the soil, especially in the neighbour-
hood of Bartley’s Forge. About three-fourths of a mile north of
the forge a small excavation for ore may be seen, which, it is
said, yielded a mineral of good quality. An opening has also
been made about a mile from Mount Olive, but it did not deve-
lope a vein of any magnitude.

Nearly a mile and a half northeast of Drakestown, on Schooley’s
Mountain, a digging was lately made (summer of 1838), which
produced some ten or twelve tons of ore, of a highly magnetic
character, pronounced to be of good quality: but it did not lead
to the developement of a regular and solid vein.

Upon the same mountain, and about a mile and a half east of
Hacketstown, some ore is visible in the soil, but of too quartzose
a nature to produce a good iron. The diggings which were made
at this spot did not succeed in disclosing a regular vein.

Upon the mountain, a few furlongs to the west and northwest
of the Heath House, ore in considerable abundance strews the
surface of the fields. A portion of the mineral here is pretty
largely contaminated with hornblende, augite, and other foreign
substances, which do not, however, materially interfere with the
reduction of this species of ore into iron, except where their quan-
tity is considerable. Much of the ore of the same locality, is dis-

35

tinguished by having the magnetic property, sometimes in a high
degree, many masses being found endowed with magnetic polarity
in unusual strength.

Numerous small openings have been made here, at various
times, in quest of a regular and solid vein, but, until recently,
none promising to be of useful quality and dimensions have been
explored. From some excavations lately made the indications
seem to be more encouraging.

In the Musconetcong Mountain, the appearances of the surface
do not justify the hope of there being any considerable veins of
the magnetic ore.

The next and last tract of the primary hills, towards the west,
abounding in this valuable mineral is Scott’s Mountain, in War-
ren county. i

A brief account of the veins in the vicinity of Oxford Furnace,
the locality of chief importance in that district, will complete the
details which we have to offer upon the subject of the magnetic
iron ore of the region.

Here, as elsewhere, the direction of the veins is parallel with
the bearing of the strata of granitoid gneiss which include them.
There appear to be at least two principal veins, but the precise
thickness of either it is difficult to ascertain, owing to their
varying constantly in their dimensions. The quantity of ore,
however, is enormously great. ‘The veins are divided here and
there, by thin beds of the rock, into several parallel branches,
so that the aggregate width of the ore has not been wrought in
many places. The adjoining strata are, moreover, considerably
disordered, and the veins are, in consequence, thrown out of
direction by two or three pretty large faults. These are con-
nected with detached or broken off portions of the lodes, two of
which are known to sweep round a curve of almost semicircular
form.

Some portions of the adjacent strata contain the oxidulated
magnetic iron in a crystalline state, disseminated in sensible pro-
portions through the rock, or rather through certain layers, either
associated with the hornblende or replacing it.

The greater part of the ore resembles in quality that of the
ranges before described, being the magnetic oxide of iron, either
compact and massive, or in granular crystallization. It has the

36

defect common to nearly all the veins in the primary region;
that is to say, it is apt to be too compact fer easy reduction
in the furnace. It yields an excellent iron, and seems especially
well suited for making castings.

Let me here be permitted to express the hope that this favoured
region of New Jersey, so eminently enriched by nature with that
most valuable of mineral treasures, iron, is destined to behold, at
no very distant day, a brighter era as a manufacturing district.
Two important new methods, recently introduced into the
smelting of iron, namely, that of the hot blast and the substi-
tution of anthracite coal for charcoal—now become in many
districts of the State too scarce to be employed—seem peculiarly
well adapted to remove some of the difficulties which attend the
use of these compact magnetic ores. ‘These obviously require a -
more elevated temperature for their profitable reduction than
can be given them by the aid of charcoal and the ordinary blast,
and seem particularly to call for the application of the modern
improvements referred to. ‘The success which has lately attended
the use of anthracite in the smelting of iron in Pennsylvania,
suggests that New Jersey need no longer be prevented from
availing herself of the advantages, arising from her superabundant
treasures in ore, by the absence of wood upon her hills.

Conclusions deducible from the previous facts —The first theo-
retical inference, naturally suggested by the remarkable manner in
which all the veins, without any exception, occuris, that the primary
strata existed in all probability at a rather steep inclination before
the intrusion of the veins; for it is inconceivable how a forcible
injection of fluid ore could-enter a series of beds, lying in a nearly
horizontal position, without in some cases causing and occupying
fissures transverse to the strike of the strata. The fact that other
similar veins—those of the altered white limestone of Sussex—
occupy a corresponding position in reference to the neighbouring
strata, and appear to have been produced after the formation of
the limestone, is another argument lending probability to the
notion that their origin was subsequent to the formation and
upheaving of the gneiss.

Moreover, it is not difficult to conceive, that if the strata
were previously nearly vertical, or at a high angle, the mol-
ten ore would easily insinuate itself in the plane of. the strati-

37

fication of the rock, this being the direction in which the strata
would most readily give way. If the rule be a general one, that
these veins range and dip parallel to the strata, we are led to
some important general hints for seeking and opening mines in
this region. One is, that the veins of ore may be expected to
follow the same layer or bed of rock for a considerable distance :
and that the nature, therefore, of the adjoining rock, will often
prove a clue for finding a previously known vein in the direction
towards which it is prolonged. Another suggestion is, that when
levels are cut, or shafts sunk to reach a vein, the indications of
which are witnessed upon the surface, the excavations should be
made on that side of the presumed outcrop of the vein which is
towards the underlie, or dip of the gneiss, because the vein, keep-
ing parallel with the rock, will descend in that direction.

Respecting the geological date of these veins of magnetic iron
ore, it seems difficult, from the imperfect nature of the data
afforded by the region, to arrive at positive conclusions. The
views which we here venture to suggest in the light of the hypo-
thesis on the subject, are offered as merely conjectural. They
are deemed at the same time worthy of a place in our account
of the geology of the Highlands, as assisting to throw light upon
other questions hereafter to arise, and as opening a train of in-
quiry interesting to future investigators—some of whom, let us
hope, may hereafter find an inviting field for research in the
structure and former physical history of this mountain belt.

In examining the question of the date of the veins of magnetic
iron ore, our attention is at once called to the interesting general
fact, that these veins lie exclusively in the primary rocks. I think
we must conclude, that most, if not all of these veins of ore, were
etruded from their deep source beneath the surface, during the
epochs which preceded the deposition of the first widely dispersed
secondary strata.

CHEMICAL COMPOSITION OF THE MAGNETIC IRON ORES OF THE
HIGHLANDS.

Suggestions concerning the treatment of these ores, can be of
service to the manufacturer only in proportion as they are the
results of numerous and precise chemical investigations into their
composition.

4

38

The following analyses will exhibit their average richness in
iron; and display, moreover, the amount and nature of the
extraneous substances, which occasionally interfere with their
reduction.

ANALYSES.

Peters’ Mine, Ringwood, Bergen county.

Description.— Ore, magnetic, perfectly granular and erystal-
line; the grains uncommonly large and distinct. Contains a few
spots of yellowish decomposed mineral. It is extremely friable.

Specific gravity.— 5112 at a temperature of 65:5° Fahr.

Composition.—Iron, - - 71:9 per cent.
Insoluble matter, 0-3. do.
Alumina, - a trace.
Lime, - - none.

Good Hope Mine, Ringwood.
Description.—Ore, magnetic, beautifully crystalline; the grains
exhibiting nearly regular facets. Contains a little interspersed
yellowish clayey matter.
Specific gravity.—5:019 at temperature 50° Fahr.
Composition.—Ilron, - - 71:88 per cent.
Insoluble matter, 15 | do.
Lime and alumina, a trace.

“ Cannon Ore,” Ringwood.

Description.—Ore, magnetic, highly crystalline; the grains dis-
tinctly angular and rather small. Contains much white and green-
ish mineral matter.

Specific gravity.—4-685 at temperature 69° Fahr.

Composition.— Metallic iron, 63-2 per cent.

Mount Hope Blue Mine, Morris county.
Description.—Ore, magnetic, compact and massive; having but
little of the granular structure. Fracture nearly flat, but not
smooth; somewhat mottled with white and greenish specks.
Specific gravity.—4:918 at temperature 65° Fahr.
Composition.— Metallic iron, : 69.6 per cent.
Insoluble matter, - 2:8 do.

39

Teabo Mine, near Dover.

Description.—Ore, magnetic, compact, slightly granular, fracture
irregular ; lustre, brilliant, metallic. Contains dispersed grains
of hornblende and vitreous felspar.

Specific gravily.—44-82 at a temperature of 69° Fahr.

Composition.— Metallic iron, - 64:9 per cent.
Insoluble matter, - 6:2 do.
Lime and alumina, a trace.

Mount Pleasant Mine, near Dover.

Description.—Ore, magnetic, compact and massive; somewhat
granular; grains less than the average size; contains greenish
and white specks of extraneous matter.

Specific gravity.— 4-697 at a temperature of 70° Fahr.

Composition.— Metallic iron, - 65:99 per cent.
Insoluble matter, - 7h Oo
Lime and alumina, slight traces.

Sterling Mine, near the Mount Pleasant Mine.

Description—Ore, magnetic, massive and granular; grains
distinct, interspersed with specks of a whitish decomposed mineral,
amounting to almost one-half the whole bulk.

Specific gravily.— 4-691 at a temperature of 66° Fahr.

Composition.— Metallic iron, - 66-4 per cent.
Insoluble matter, - 4:4 do.
Alumina, rather more than a trace.

Succasunny Mine.

Description.—Ore, magnetic, highly crystalline; grains large
and distinct.
Composition.—Peroxide of iron, - 70:00 per cent.
Protoxide of iron, = - 28:25 do.
Oxide of titanium, a trace.
Oxide of manganese, a trace.

Oxford Furnace Ore, Scott’s Mountain, Warren county.

Description —Ore, magnetic, and somewhat granular and fri-

40

able. Contains numerous grains of felspar, hornblende, and other
extraneous minerals.
Composition.—Peroxide of iron, - 67:25 per cent.
Protoxide of iron, = - 26:50 do.

Oxide of manganese, - 0°50 do.
Oxide of titanium, - a trace.
Silica, 3 - 2:10
Alumina, &c. - = 3°00

The analyses of these ores being undertaken with a view to
ascertain more particularly the quantity of metallic iron, the pro-
cess adopted was to dissolve the powdered ore in nitro-muriatic
acid, precipitate the iron by potash, to redissolve it in excess of
acid, and subsequently precipitate it by ammonia.

A portion, considered as representing the average composition
of the specimen, was selected for examination. In each instance
the specific gravity has been taken by Nicholson’s hydrometer.

Five or six times the amount which was employed for analysis
being finely pulverized, from ten to twelve grains were generally
used, this being found the most convenient quantity for accuracy.

It deserves the attention of those engaged in manufacturing iron
from these ores, that very frequently the portion of the vein lying
immediately beneath the surface, and the fragments and grains of
the ore, which often fill the soil in very considerable abundance,
are much softer than the ore in the main body of the vein. The
action of atmospheric agents upon it appears to have rendered it
more yielding, and it consequently mingles more readily in the fur-
nace with the other materials, greatly facilitating the smelting of
the mass. The clay and earthy matters, which remain attached
to the surface ore, even after it is washed free from the loose soil,
account, in part, for its beneficial effects; for, the highly silicious
nature of the foreign minerals in the ore, seem to counteract, in
part, the fluxing agency of the limestone, and render it less
efficient than when other ores are smelted. Some trials have
been made at the Oxford Furnace, which consisted in mixing a
loamy clay with the ore, in addition to the limestone, and were
decidedly encouraging. The loose surface ore, therefore, merits
the attention of the smelter. At Oxford Furnace, the soil con-

41

taining it is washed in a stream of water, running through
troughs; after which it is sifted, and the increase in the product
proves that the extra labour spent in preparing it is economically
bestowed.

In two or three places, in the iron region, magnetic separating
machines are used to clear the ore of the foreign mineral matter
with which it there is mixed. They are applied, of course, only
when the quantity of non-metallic matter is so large as to consti-
tute a motive for removing it; nor are they admissible except
where the ore is highly magnetic. One has been used at Ring-
wood, and another at Hibernia.

It is a curious circumstance, that the igneous injections, pene-
trating the older secondary limestone of the chain of valleys,
north of the main range of the Highlands, from Amity, in New
York, to Scott’s Mountain, producing a striking change in its
structure, though sometimes wholly metalliferous in their nature,
rarely embrace veins of magnetic iron ore such as belong to the
_gneiss of the Highlands.

Some of the veins of magnetic iron ore, penetrating the gneiss,
may, therefore, claim an earlier date than those metalliferous
and non-metalliferous veins which traverse only the subsequently
formed blue limestone.

The highly singular phenomena, connected with the intrusion
of these last named veins in the limestone rocks of the valleys,
will demand a particular description, which it is deemed proper,
however, to defer, until the general geology of the older secondary
strata shall have been previously discussed.

Gneiss Formation of Trenton—The very extensive belt of
stratified primary rocks, which ranges nearly parallel with the
Atlantic coast, and forms the western limit of the tide in the
rivers of Virginia, Maryland, Delaware, and Pennsylvania, after
gradually contracting in width, crosses the Delaware at Trenton,
and soon entirely vanishes, dwindling to a point about six miles
to the northeast of the state metropolis. Its further course
through the State is concealed by the overlying horizontal depo-
sits of clay and sand, referable to the greensand series. ‘The
formation again comes into view in Staten Island, Long Island,
and New York.

Where it crosses the Delaware, this belt of gneiss is about

4*

42

three and a half miles broad, narrowing in its course to the north-
northeast, until, by the overlapping of the newer beds upon it,
the visible portion of the formation fines away almost to a point,
about the sixth mile-post upon the Delaware and Raritan canal.
The triangular area which it forms has the valley of the Assun-
pink very nearly for its southeastern boundary, while its north-
western margin is formed by the lower members of the overlying
middle secondary sandstones. Throughout the whole included
space, the mineralogical character of the rock is extremely well
marked. It is usually a triple mixture of quartz, felspar, and
hornblende, the latter being frequently replaced by mica. Like
the rock of the other primary zone of the State, the Highands,
it goes very frequently under an improper name, being called a
granite, and sometimes a sienite. Its well-marked dip and strati-
fication, its occasionally schistose structure, and the decisive fact
of its running in strict continuity with the acknowledged gneiss
rock of the Schuylkill above Philadelphia, are sufficient to esta-
blish its claim to be considered a portion of the great Atlantic
belt of gneiss.

A little north of Trenton, and near its border, there is a
quartzose variety of the rock, containing a little mica, giving it
the laminated form, but the mass of the rock is a close-grained
stratified mixture of felspar and quartz. This band consists of an
intimate mixture of quartzose and felspathic matter fused together.
It seems to be continuous with the felspathic rock of Barrel Hill,
in Montgomery county, Pennsylvania. Splitting into rather well-
formed large slates, and having a smooth surface, it furnishes a
very good flag stone for the walks and steps in Trenton.

Wherever the stratification of the gneiss can be seen, it is found
to dip at a steep angle, nearly 70°, to the southeast. And there
can be no doubt that it underlies unconformably both the upper
secondary, or greensand deposits on its southeast, and the middle
secondary, or argillaceous red sandstone formation, on its north-
west. One variety of the rock possesses the general aspect of a
sienite, and another often contains such an excess of hornblende
as to cause it to resemble closcly a greenstone or basalt, for which
it might be taken were it not for the stratified structure evident
in almost every mass. In some portions the quartz is blue, semi-
transparent, and opalescent, and the hornblende and felspar show

43

a tendency to decomposition. It is met with of this variety upon
the canal about two miles from Trenton, and in several places
further to the northeast, as far as the spot where the rock ceases
to show itself in place, which is about three and a half miles from
the town. It may be traced about two miles further, by observing
the character of the diluvium above it.

Its economical importance consists chiefly in its including seve-
ral valuable varieties of building stone, well adapted to structures
demanding solidity and strength. Some of it would make a very
fine road-stone. To the scientific world it is interesting, as pre-
senting one of our few localities of zercon, which occurs about
fifty yards above the bridge at Trenton. The soil over this
formation is a very heterogeneous mass of diluvium, derived from
the gneiss and the formations to the northwest. It is generally
gravelly. In the valley of the Assunpink it is often a greenish
sand and gravel, derived from the quartz and hornblende, and is
then rather sterile.

CHAPTER II.

OF THE OLDER SECONDARY OR APPALACHIAN ROCKS.—GEOLOGY OF THE
KITTATINNY VALLEY, WITH ITS BRANCHES, AND OF THE REGION OF
THE KITTATINNY MOUNTAIN.

Nature and Composition of the Strata.—Having in the last
chapter described the general and local geology of the primary
districts of the State in as much detail as the limits of the present
work would permit, I propose, in the present place, to offer a
similar account of the geological features and structure of the
region occupied by that extensive group of formations of exclu-
sively sedimentary origin, which I conceive to have been depo-
sited during the period that next succeeded the first elevation of
the primary strata.

As these sedimentary rocks repose in immediate contact with
the gneiss, presenting, from the attitude of their beds, abundant
evidence that they were precipitated upon it while it was yet
only in part elevated above the waters, and, as the same strata,

dt

moreover, hold a similar relation to our primary rocks throughout
their entire range, from Vermont to Alabama, separated from
them by no other group of strata yet discovered, claiming an
earlier origin, | have deemed it expedient, for the sake of classi-
fication, to confer upon them the title of the Older Secondary Strata
of the United States. Constituting almost the entire chain of the
Appalachian or Alleghany system of mountains, in which the
whole series is not only much more complete but better developed
than in an any other region of the continent, I have thought it
judicious elsewhere in my geological descriptions to propose
for these rocks the synonyme of the Appalachian System of
Strata.*

Comparing them with the older secondary rocks of Europe,
they are evidently related, as respects their date, more nearly to
the English silurian strata than to any other known system. The
probable extent of their affinity to these will be touched upon
under another more suitable head.

Confining our attention in this place to those members of the
older secondary series which enter the territory of the State, they
will be found to comprise the five lowermost formations of that
extensive group, together with the lower division of the eighth
(the sixth and seventh being absent), counting always in the
ascending order.

The first, or lowest of these, seen only in two or three localities,
is a white sandstone, Formation I. of the general Appalachian
series; the second in the order of superposition, is the blue lime-
stone of the Kittatinny Valley and its branches, and is Forma-
tion II. of that group; the third great stratum is the slate of the
same wide valley, and in the general series is Formation III. ;
the fourth is the rock of the Kittatinny, or Blue Mountain, a
gray sandstone, passing into conglomerate, and is designated as
Formation IV.; the fifth is the red sandstone, Formation V.,
occupying the northwestern flank and base of the Kittatinny
Mountain; while the sizth, and uppermost, is the blue fossiliferous
limestone, skirting the valley of the Delaware, from Wallpack
Bend to Carpenter’s Point, being the lower division of Forma-
tion VIII. of the same Appalachian system.

* See Annual Reports on the Geological Survey of Pennsylvania.

45

The following table will serve to explain more clearly the
order of stratification, and the prevailing composition of these
several rocks.

TABLE,

Of the Lower Secondary or Appalachian Rocks, as they occur in
New Jersey.

[ates Sale PREVAILING COMPOSITION OF THE STRATUM conrad
ASCENDING ORDER. ; THICKNESS,

A light blue and gray limestone; some of
the beds argillaceous; others, more or
*VITI. less magnesian ; many layers abound- Probe 208
ing in fossils. Lies at the bottom of :
Formation VIII.

A group of alternating red sandstones,
and red, argillaceous shales; the lower ’
We layers, a very compact and ponderous Abou aie?
sandstone, of a claret red colour; These ect.
contain fossil fucoides.

A set of compact white and gray sand-| About 2000

IV stones, with layers of quartzose conglo-| feet at Dela-
: merate. Contains several species of fu-| ware Water
coides. Gap.

A thick mass of dark, argillaceous slates
—bluish, black, gray, greenish-gray, or | Not positively
olive, yellowish, and red. Affords good known. but
Til, roofing slate; contains, also, beds of thought to
dark gray sandstone, and a few layers be at least
of conglomerate. Occasionally exhibits} 30900 feet.
marine fossils.

Not positively

A blue limestone, occasionally magnesian. known ;
a. Contains thin beds of chert. probably
upwards of
2000 feet.

Whole thick-

A compact and very quartzose sandstone,| €ss not as-
I. of light bluish-gray colour, approaching ceriained,

to white. owing tode-
nudation.

46

SECTION I.

Of the White Sandstone—Formation 1.

Geographical Extent—This formation, so largely developed
in Pennsylvania, in the flanks and even summits of the hills,
which constitute the same chain as the Highlands, I have hitherto
discovered in only three or four small isolated tracts in New
Jersey. The first locality, commencing towards the northeast,
is north of the Pequannock, between Long Pond and Macapin
Pond. Its position is in a narrow belt of the ancient secondary
rocks, which extends for several miles along the confined valley
included between the eastern base of the Green Pond Mountain
and the primary hills directly east. ‘The first visible mass of the
sandstone occurs about two miles north of the farm of Richard
Gould, Esq., or about four miles south of Long Pond. The rock
here lies near the base of the primary hills. It probably extends
southward in a continued belt for several miles bencath the lime-
stone (Formation II.) of the same valley, though it does not
show itself again until we reach the farm of Mr. Gould, where it
is displayed near the head of Macapin Pond, in an interesting
exposure, at the base of a ridge of the limestone, dipping beneath
that rock at an angle of 60°.

The next spot at which this stratum reveals itself at the
surface, is, in the prolongation of the same valley, and about
midway between Flanders and Succasunny Plains. The rock
occupies a small low hill, nearly but not exactly in a line with
the low ridges which constitute the denuded extremity of the
Copperas Mountain at Succasunny. The stratum has evidently
sustained extensive denudation, only a patch, not more than a
mile in length, of the lower portions of the formations being left
in the middle of the valley. The rock is nearly white, very
quartzose, and somewhat friable in texture to a considerable
depth below the soil, yielding, therefore, a very pure white sand.

The only remaining locality at present known occurs on the
northwestern side of the small ridge of primary strata, which
commences a little to the west of Hacketstown, and extends
thence southward about four miles. The range of the sandstone,

47

occupying a confined area upon this ridge, is very limited. The
rock is of a grayish white, has an even texture, dresses readily
under the hammer of the mason, and is, in many respects, entitled
to attention as a material well adapted for architectural uses.
It has been occasionally employed with that view at Hacketstown.

Almost every where else along the boundary which separates
the limestone from the primary rocks, where this formation sheuld
be found, we find either no traces of it whatever, or else here and
there a debris, consisting of a white sand and gravel, derived
from the destruction of the rock at its outcrop. The frequent
accumulation of the large deposits of diluvial matter at the bases
of so many of the primary hills, together with the easy destructi-
bility of the rock itself, which can nowhere within the State have
attained to a great thickness, will serve to explain the very
limited extent to which it is exposed.

SECTION II.

Of the Blue Limestone (Formation IL) of the Kittatinny Valley and

- its Branches.

The second rock of the Appalachian series which we meet
with in the ascending order, is the great blue hmestone formation
of the southeastern half of the Kittatinny Valley, and of most of
the valleys included between the several ranges of the primary
hills, or Highlands.

Geological range of the Formation.—Omitting, for the present,
the task of tracing the lesser belts of the blue limestone, which
occupy the narrow longitudinal valleys of the primary chain and
the valley of the Paulinskill, and restricting our attention to the
principal tract of this formation in the State, we may define it in
general terms, as occupying the southeastern half of the Kitta-
tinny Valley, understanding this name in its most comprehensive
sense as extending to the base of the long continuous mountain
range, known as the Wallkill, Schooley’s, and Musconetcong
Mountains. Within this broad belt rise up a number of the de-
tached primary ridges of the general chain of the Highlands,
whose exact position and boundaries we have already traced.

The continuity of its surface is still further interrupted near its

48

northeastern margin, by a succession of long and narrow syn-
clinal belts, consisting of the slate of the overlying formation.

The general southeastern border of this large limestone district
has been already traced in sufficient detail, when describing in -
another chapter, the northwestern limit of the main continuous
range of the primary, above referred to. It was stated as keep-
ing a little to the southeast of the Musconetcong creek from its
mouth nearly to Stanhope, towards its source, and thence to
extend in a more wavering line along the base of the Wallkill
Mountain to New York.

Its northwestern margin, separating it from the main continuous
slate belt of the Kittatinny Valley, may be given as extending
longitudinally in a somewhat undulating course, through the middle
of that valley, from a little above Belvidere, on the Delaware, to
near the intersection of the Wallkill and the state line of New
York.

Tracing this boundary more minutely, it will be found, begin-
ning at the Delaware, to run in a northeast direction for about
four miles, to the little village of Sarepta, to deflect thence north
for several miles, to the Free Church, on the road from Hope to
Columbia ; passing which, it sweeps again towards the east, until
it reaches the vicinity of Johnsonburg. From this point to the
New York line, it preserves a nearly straight course, skirting
the town of Newton on the northwest, passing a little west of the
village of Harmonyvale and a corresponding distance east of
Deckertown, and meeting the meadows of the Wallkill about |
three miles to the southwest of the line bounding the State.

The large zone of limestone now delineated, offers many curi-
ous features to the geologist. Conspicuous among these are its
numerous anticlinal axes and the striking phenomena of an in-
duced crystallization, effected along certain belts of the stratum
by the heating agency of the numerous igneous dikes and veins
which traverse it. ‘These will be systematically described and
traced in their own more appropriate places. In the mean while,
we proceed to give the boundaries of the other lesser bands of
the limestone formation.

Next in extent of surface to the broad area already traced, is
the smaller parallel tract of the valley of the Paulinskill, lying to
the northwest. Commencing at Coursinville in a wedge-shaped

49

point, in the midst of the wide tract of the slate of Sussex county,
it ranges southwestward, following nearly the valley of the Pau-
linskill creek to its mouth, and terminating in another wedge-
shaped point on Cobus creek, in Pennsylvania, about a mile and
a half beyond the Delaware. It has the form of a long, con-
tinuous, and nearly straight belt; varying between one and two
and a half miles in breadth. The only conspicuous irregu-
larity in its margin, is where a long narrow tongue of the over-
lying slate intrudes itself into this tract northwest of Newton,
following the immediate valley of the Paulinskill for several
miles.

The physical features of this extensive range of the limestone,
are those of a valley deriving its outlines from an active denuda-
tion of the rocks along an axis of elevation which traverses it
nearly centrally from one extremity to the other.

On the opposite or southeastern side of the main zone of pri-
mary rocks which crosses the State, we meet with the limestone
extending at somewhat interrupted intervals in a long narrow
band, in the bed of that great continuous valley which separates
the main chain of the Highlands longitudinally into two nearly
equal wide belts of hills.

Taking up this range of the limestone at its northeastern
extremity, the first narrow band which we encounter, is be-
tween the outlet of Long Pond, and the outlet of Macapin
Pond; along the eastern base of the Long Pond Mountain. This
exposure of the rock is about three and a half miles in length,
commencing about two and a half miles north of Macapin Pond.
Another very small patch of the limestone presents itself about
one mile to the northeast of the head of Green Pond. Both
this and the former locality, exhibit a considerable quantity of
fossil marine shells in the rock, belonging, however, to but a
limited number of species. Elsewhere, throughout the State,
this limestone formation is singularly deficient in organic re-
mains; and consequently, these isolated tracts derive consider-
able interest to the geologist from their fossiliferous character.

Extending our researches through the same general valley, we
again come upon the limestone, about two miles to the southwest
of Flanders, from whence we may trace it in an interrupted belt
down German Valley to Clinton, and thence along the south-

5

50

eastern base of the Musconetcong Mountain, past Vansickle’s to
Pattensburg, reappearing again within a few miles of the Dela-
ware, and extending to the river.

The small isolated range of this limestone in Mendham Valley,
forms the only remaining tract of the formation in the State. It
occupies the bottom of the valley, lying between the base of the
Mine Mountain and the Trowbridge Mountain, and first shows
itself about a mile east of Mendham, from whence it extends to
near the mill, which is a short distance below the village. There
it disappears beneath the overlying beds of the middle secondary
red sandstone series, which repose unconformably upon it. It
soon emerges again from beneath this covering, and may be
traced nearly fan Ralston’s to the Pepack iepale

Composition and Structure of the Rock—This rock possesses
a remarkable diversity of aspect and composition. It assumes
almost every variey of tint, from a deep blue, almost approaching
to black, to the lightest shades of gray; but its prevailing colour
is a soft grayish blue. It is equally multifarious as to texture,
presenting every possible gradation, from an almost crystalline
character, to the closest and finest earthy aggregation’ of the
particles. When the latter character is associated with a clear
tint of blue, and with a sharp, smooth, well-defined and conchoidal
fracture, the rock usually consists of pure carbonate of lime ; while,
on the other hand, a rougher texture, a duller tint, and a more
irregular surface of fracture, indicate the presence of other
materials.

The extraneous ingredients which most abound, are carbonate
of magnesia, alumina, and silica ; while oxide of tron and carbon
also frequently enter into its composition, but in less proportion.
The rock is sometimes sandy, especially in the lower part of the
formation; and it is frequently in other portions more or less
argillaceous, in which case it is apt to present a partially slaty
structure. It is also thin-bedded or flaggy, but oftener occurs in
layers of from several inches to a foot or more in thickness.

Throughout a large portion of the geographical range of this
rock, it exhibits in a greater or less degree, the oblique cleavage
planes, so conspicuous in many belts of the slate, which adjoins it.
As this interesting subject of the cleavage of rocks will be consi-
dered rnore in detail when discussing the geclogical features of

51

the slate, it is passed by for the present, with the remark that the
general direction of the cleavage planes in the limestone follows
strictly that which prevails almost universally in the slate, the
dip and strike of these planes of cleavage being in both formations
entire, independent of the direction of the dip of the strata.

Axes of elevation affecting the Formation.—Seeking by the study
of the external phenomena of a formation, to understand either
the revolutions in the past physical condition of its district, or the
present structure of that portion of the earth which it constitutes,
we shall find it essentially important to examine in an early stage
of the inquiry, the nature, extent, and relative situation or direc-
tion of all the axes of elevation, which may disturb its beds from
their original nearly horizontal position. ‘These axes of elevation,
marking the lines along which the subterranean forces have ex-
erted themselves in their greatest energy, are the surest guides
We can possess, not merely to the changes which the strata may
have undergone, both of displacement and of alteration of struc-
ture; but to the existing position of every thing they may regu-
larly include, whether it may interest science only, or prove
particularly useful to the wants of man. They show us what
portions of the formation have become deeply buried beneath the
surface, and often at what depths, whether accessible or inacces-
sible, and they inform us what portions of the formation have
been removed from the surface, by the crushing and washing
away of the strata along the lines where they were most up-
lifted. ‘They constitute, in fact, an indispensable clue to the
operations of the miner, the quarryman, and even the road-
maker, in every much convulsed district where they may abound.

As, therefore, the primary chain of the State, and the whole of
the great valley which borders it upon the northwest, are tra-
versed longitudinally by a most extensive system of such axes,
lying mutually parallel and closely contiguous, and connected
intimately with nearly every point in their geological structure,
both general and local, I deem it important to introduce here a
systematic enumeration of all such as are of much note, intend-
ing, as I proceed, to exhibit their relations to the disturbances
and changes of structure, caused in the adjoining strata.

Pursuing our usual course, from the northeast towards the
southwest, and examining first the southeastern belts of the forma-

52

tion in the Kittatinny Valley, we commence with that axis, or
rather, probably, that chain of axes, which we find ranging in the
prolongation of the Pochuck Mountain.

That the oval-shaped primary hill, called the Pochuck Moun-
tain, owes a part at least of its present altitude, to an axis of
elevation passing through it longitudinally from north-northeast,
to south-southwest, is rendered sufficiently apparent by the anti-
clinal posture of the limestone reposing at its base; that which
flanks it on the southeast dipping towards the Pochuck Valley ;
while that at its northwest foot has an inclination towards the
valley of the Wallkill, in the opposite direction. The valley of
Black and Warwick creeks, which I here call the Pochuck
Valley, contains the limestone in a trough, considerably disturbed,
however, from a symmetrical synclinal structure by a series of
igneous dikes of mineral matter, ranging at broken intervals, at
a nearly straight line from Amity, in New York, to a point a
little south of Hamburg, which either locally derange, or alto-
gether obliterate the dip of the limestone by fusion and recrystal-
lization. The prolongation past Hamburg of this synclinal axis,
is not clearly traceable, in consequence, most probably, of the
close approach of the uptilting primary rocks of the Hamburg
Mountain to those of the Pochuck Mountain; at this vicinity the
upheaving influence of the former countervailing, for a limited
space, the anticlinal axis of the Pochuck Mountain, causing all
in the tract immediately southwest of Hamburg to dip along a
certain distance towards the northwest. But tracing what ought
to be the line of the Pochuck axis, a little further towards the
southwest, we find distinct evidence throughout a belt having a
somewhat confused anticlinal dip, of its prolongation under the
limestone between Hamburg and Munroe. It would seem not to
extend as far as the turnpike, south of the village of Lafayette;
for though the limestone displays a northwestern dip along the
margin of the slate, both at Munroe and on the turnpike, we can-
not find in the proper places any corresponding dip to the south-
east, which might give proof of a continuation of the axis so far
towards the southwest.

Another axis of elevation is traceable in Pimple Hill, for the
limestone at its southeastern base is seen dipping from the hill, or
towards the southeast; and we have already recorded the north-

53

western dip of its beds on the western side, or between Munroe
and the turnpike. Though the stratification is locally much con-
torted and disturbed in the valley between Pimple Hill and Ham-
burg Mountain, by the violent disrupting igneous agencies, which
have so extensively altered the texture of the limestone, yet the
general structure of this belt is that of a somewhat irregular
synclinal trough, which may be traced past Sparta into the valley
of Lubber run, though with many interruptions to the regularity
of the synclinal axis. The portion of this valley between Sparta
and Lockwood owes the uplifting of its beds, along the north-
western side, to an axis occupying longitudinally the narrow
primary ridge which stretches from Sparta to Andover village.

The dip of the limestone becomes, however, very irregular as
we approach the several insulated primary knobs in the vicinity
of Lion Pond and Panther Pond, and between these and Stan-
hope. Just north of Panther Pond, the little limestone which is
visible is seen to dip towards the northwest, evidently thrown off
into that position from an axis in one of these knobs. Whether
the axis of the Sparta ridge, that of the knob south of the pond,
and that traversing the ridge which passes Alamuche, belong to
one line of elevation, or whether, more probably, they are discon-
tinuous, is a point not readily settled, owing to the obscure expo-
sure of the limestone and gneiss, which are here much covered
by diluvium, and to the remarkable intricacy of the country be-
tween Lockwood and Andover village.

Between Panther Pond and Lockwood, though there are pro-
bably several contiguous short anticlinal axes in the primary
knobs, including, no doubt, intervening troughs of the limestone,
yet this rock has been subsequently so affected by extensive
igneous agency in this quarter, as to show an almost total loss of
regularity in its dip.

Prolonging our observations southwestward, we find in the
comparatively broad tract of primary rocks, which lies between
Lockwood and Vienna, indications of more than one axis of
elevation in the gneiss. The most southeastern of these has up-
heaved the limestone rocks of the northwestern side of the
Hacketstown Valley, imparting to them their present dip to the
southeast. This axis has probably brought to the surface, the
narrow tract of gneiss, extending from Hacketstown towards

5*

54

the Mount Bethel Church, pursuing the same line of elevation,
namely, that immediately west of Musconetcong Valley, we trace
the same anticlinal line, or more probably, one parallel and nearly
continuous with it, through what is termed the Mansfield Valley.
This is properly the axis of the upheaved belt of gneiss which lies
between the Musconetcong and Pohatcong streams. We have
proofs that the elevatory force extended southwestward, nearly
to the Delaware, inclining the beds of limestone, on the one hand,
towards the Musconetcong; and on the other, towards the Po-
hatcong.

That this axis of elevation is not strictly coincident with that
which comes in to meet it from the northeast, is rendered likely
by the variable undulating dip of the rocks along the centre of
the Mansfield Valley, where these axes should pass. It is a phe-
nomenon which the geologist may often have occasion to remark
when detecting the near juxtaposition of two anticlinal axes
which overlap or pass each other, that the strata immediately
within its range are almost invariably thrown in a succession of
opposite or undulating dips.

To the southeast of the general axis of elevation, viewing it as
one, thus traceable from near Lockwood to the Delaware, we
have the singularly uniform straight and narrow synclinal valley
of the Musconetcong, along nearly the whole length of which
the limestone will be found dipping away from the hills which
bound it towards a synclinal axis, which ranges not exactly along
its centre, however, but lies nearest to its southeastern margin,
approaching the stream itself. ‘This departure from a central po-
sition in the synclinal axis of the valley, is a very usual feature in
the axes of the Appalachian chain. It results as a necessary con-
sequence from the northwestern dips belonging to the anticlinal
axes lying next to the southeast, or that of the Schooley’s Moun-
tain chain, being steeper than the southeastern dips from the axis
of elevation northwest of it. This want of symmetry in the dip
of the strata would not claim a special mention in this place, but
for the truly remarkable circumstance, that throughout nearly the
whole length of the Appalachian chain, embracing many hundred
anticlinal axes, the same rule prevails with scarcely an exception,
the northwestern dips being steeper than the opposite south-
eastern ones.

55

Resuming our delineation of the anticlinal axes which affect
the limestone formation of the Kittatinny Valley, the next in order
which plainly manifests itself to the northwest of the general line of
elevation already described, belongs to the small ridge of primary
rocks which runs very nearly in the prolongation of Pimple Hill,
southwestward from the turnpike towards Long Pond. South of
the pond, this axis is distinctly traceable in the limestone nearly to
the next turnpike, which passes through Andover. If this and
the axis of Pimple Hill are not identical, they are most probably
the joint results of one elevatory force, exerted along a nearly
continuous line. West of Andover, this line of elevation in the
limestone is no longer traceable, the dips of the rock on the
northern side of the Pequest being referable to the more influen-
tial axis which is prolonged from the violently uplifted ridge of
Jenny Jump.

Between the short axis now described and that of the Sparta
ridge southeast of it, we meet with a narrow belt of limestone,
coming to a point towards Pimple Hill. In this belt, which opens
out towards the southwest in the more expanded synclinal basin,
southeast of the Jenny Jump axes, the limestone is much disturbed,
and along its eastern side is in some places entirely crystallized
by igneous agency.

The axis of elevation which passes longitudinally through
Jenny Jump, is plainly exposed in the limestone for several] miles
in both directions. At the southwestern extremity of the ridge it
passes to the south of the little village of Sarepia, and parallel
with the base of Scoit’s Mountain towards Belvidere, forming a
small synclinal basin in the secondary rocks, between Bridgeville
and Belvidere. Along this anticlinal axis, especially near the
mountain, the beds of the limestone are highly uplifted, and in
many places, greatly crushed.

The movement which elevated Jenny Jump, seems to have
been every where one of excessive suddenness and violence, as
the strata along its anticlinal axis are not only there frequently
much dislocated and broken, but those lying immediately along
its northwestern base, are in several places thrown into an in-
verted posture, dipping, not to the northwest, but in towards the
base of the hill.

Tracing this anticlinal axis towards the northeast, we find it

56

exhibited in very steep, and somewhat disturbed dips in the lime-
stone, for a short distance beyond the termination of the moun-
tain. It afterwards becomes more regular, and may be discovered
running for many miles in a nearly straight course, passing a
little to the east of Greenville. Between this point and the turn-
pike, we fail to follow it in consequence of the difficulty of pro-
curing distinct exposures of the strata; but about a mile north-
east of the turnpike, we perceive an anticlinal axis, ranging
somewhat parallel with and northwest of Long Pond, and coin-
ciding so nearly in direction and position with this of Jenny Jump,
as to warrant us in regarding it as a portion of the same line of
elevation near its northeastern termination. Were this axis pro-
longed yet further to the northeast, it would constitute one long
and nearly straight axis with that which approaches it from the
northeast, through the centre of Pochuck Mountain; but as we
have already shown that the latter subsides near Munroe, we
have a space of several miles along which their continuity is
interrupted.

Adverting now to the synclinal basins, included between this
main axis of Jenny Jump and the chain of axes previously traced,
lying to the southeast of it, we discover the limestone to form one
general trough, in the valley of the Pequest, between Greenville
and the Alamuche belt of the primary. But passing the Andover
turnpike, this trough runs into two, on account of the interposed
short anticlinal axis, prolonged from Pimple Hill. Between the
anticlinal axis and Alamuche, the southeastern dips are observed
to occupy, as they frequently do, a much wider belt than the
northwestern one, the latter being by far the steepest. Whether
farther towards the southwest, between Jenny Jump and the
ridges east and south of the little village of Vienna, the limestone
of this tract may not be disturbed from the simple synclinal
arrangement which it has near Alamuche, in consequence of one
or more short axes of elevation extending into it from the spurs
of Scott’s Mountain, is a question not readily answered, owing
to so large a portion of the surface of the limestone being hid
from view, first by the Great Meadow, and southwest of this, by
the large accumulations of diluvium in that quarter.

That such short axes do disturb the limestone near Scott’s
Mountain, is, however, highly probable, even from the few dips
disclosed.

57

Though it is difficult to trace the axes of elevation as they
traverse the primary ridges, on account of the frequency of the
igneous injections in the gneiss producing much contortion in the
strata, yet viewing the topography of Scott’s Mountain in con-
nexion with the more regular dips which it discloses, we cannot
resist the impression, that it owes its elevation to at least two
considerable anticlinal axes.

One of these would seem to range along its southeastern ridges,
passing not far from Oxford Furnace, and southwestward be-
tween the Lopatcong and Merrill’s brook, affecting the limestone
north of the former stream. The other observes a more north-
western line, and is probably connected with the elevation of the
primary ridge, called the Marble Mountain, at the Delaware. At
the southeastern base of Scott’s Mountain, we find the limestone
assuming the synclinal structure in the valley of the Pohatcong;
but not every where symmetrically, as it gives evidence, especially
as we approach the Delaware, of being in some places actually
inverted along its southwestern border.

It is difficult, indeed, to find the rocks any where dipping to
the northwest, throughout the whole distance from the Pohatcong,
across their strike, to the base of Marble Mountain. ‘This indi-
cates, in the Kittatinny Valley, that those belts of the stratum
lying to the northwest of each anticlinal axis, instead of assuming,
as we would expect, a northwestern dip, have been so forcibly
upheaved in that direction as to have been tilted in many cases
beyond the vertical plane, and made to fold over, with a south-
east dip, upon the southeastern dipping beds belonging to the next
northwestern axis. Connected, most probably, with some early
movement of elevation in the strata around Jenny Jump, there
occurs an interesting and rather unusual phenomenon, in the nar-
row belt of limestone ai the base of the mountain, immediately to
the southeast of the little village of Hope. We allude here to the
uncommon structure of the rock, which is at this place a true
conglomerate, made up entirely of pebbles and rotted fragments,
some of them being many inches in diameter, which, like the
paste imbedding and cementing them, consist exclusively of the
same materials as the rest of the blue limestone formation, in
which this conglomerate occurs as one of the interposed beds.

The same formation embraces, in Pennsylvania, a similar

58

included stratum, occupying, to all appearances, a corresponding
position in the general mass of the limestone. This occurs on
the Northkill, a little above the village of Bernville, in Berks
county: these are the two principal localities at which I have
hitherto discovered this coarse, calcareous conglomerate. But
I am authorized by my brother, Professor William B. Rogers,
the state geologist of Virg’nia, to mention, that an equivalent
rock prevails in the same relative place in the geological series,
at several points along the Kittatinny Valley in that State.

This cong!omerate imparts interest to all inquiries respecting
the date of the disturbances which have elevated our great series
of Appalachian rocks, throughout their prodigious range, from
Vermont to Alabama: it distinctly implies that the shores of the
Appalachian ocean were agitated at the early epoch at which
the limestone was produced, by a movement sufficiently violent to
shatter and convert into pebbles some of that rock already
deposited.

The facts above adduced, prove, also, that, though apparently
sudden and of short duration, this convulsion of the limestone
ranged, if not uninterruptedly at least at intervals, far to the south-
west, along the same line of ancient shore: for it is indisputable,
that the general belt of the Highlands, and their prolongation
southward, formed the general southeastern coast of the great
ancient secondary or Appalachian sea, if not every where at the
commencement of these deposits, certainly after the first two or
three formations were accumulated.

The next main axis of elevation beyond that of Jenny Jump, is
traceable from near Deckertown southward, passing the villages
of Harmonyvale, Lafayette, Newton, and Johnsonburg. Strict
continuity of the anticlinal axis between these several points is
not, however, clearly established; and, very possibly, it is rather
a succession of two or three coincident axes than one of unbroken
regularity: the upheaved belt of limestone containing this chain
of axes is itself uninterrupted from the Wallkill, near Decker-
town, to Johnsonburg, its northwestern margin; and that of the
belts on its southwestern prolongation, at Hope and ‘Belvidere,
have been delineated in detail when describing the geographical
range of the formation. On the southeast, between this anticlinal
belt of the limestone and that which contains the axes of the

59

Pochuck and Jenny Jump Mountains, there is a long and narrow
zone of the overlying slate, Formation III. This starts from the
Wallkill, about three miles northeast of Deckertown, and ranges
in an attenuated ridge, until opposite Newton, passing about half
a mile east of Harmonyvale and Lafayette. It presents through-
out its whole length a regular synclinal structure. lying in the
middle of the trough of limestone, formed by the two parallel
anticlinal axes above referred to. About four miles southwest of
the termination of this narrow range of slate, another commences,
beginning between Reading’s Pond and the turnpike, and passing
a little west of Greenville. Between this belt, which is very
narrow, and Grass Pond, near the anticlinal axis, occurs another
similar small range of the slate. The two parallel little ridges of
this rock lie.in the prolongation of the general synclinal trough,
between the two main anticlinal axes, separated, however, by a
short interposed axis of elevation, traceable between them from
Reading’s Pond, southwestward. Each belt of the slate has,
therefore, the structure of a narrow synclinal ridge.

Lying a little further to the northwest than the principal axis,
which passes Johnsonburg, there commences an axis which
elevates the limestone of the oval tract, extending from near
Johnsonburg nearly to Sarepta.

The axis to which we now allude passes a little northwest
of the village of Hope, dying out beneath the slate towards
Sarepta. Between it and the northwestern dipping limestone,
uptilted by the axis of Jenny Jump, we may trace another long,
narrow, and nearly straight belt of the slate. This small ridge
of the slate, like those previously mentioned, contains a synclinal
axis running centrally along it.

Besides the anticlinal axis which ranges a little northwest of
Hope, we have indications of another shorter one, lying between
it and the western margin of the limestone. But this lesser axis,
the presence of which explains the sweep towards the westward
at this place, at the edge of the upheaved rocks, has not been
accurately traced, owing to the fewness of distinct exposures.

The last of the main anticlinal axis of the Kittatinny Valley
towards the northwest, is that of the limestone belt of the valley
of the Paulinskill.

This axis may be pursued for nearly the whole length of this

60

limestone valley, from northeast of Augusta to the Delaware
river. Its usual position is somewhat to the southeast of the
middle of the valley. Like many of the others, upon its south-
east it is not always symmetrical, the strata on its two sides
dipping at different degrees of inclination, and being, besides,
often separated by either a crush of the rocks near their turn, or
by a partial dislocation immediately at the axis.

West of Newtown the general belt of limestone is traversed,
for a space of several miles, by a narrow tract of the slate,
causing its northeastern termination to be in the form of two
wedge-shaped prongs, one ending near Courserville, the other
about three miles north of Newtown.

This southeastern branch, from the main tract of the limestone,
contains, we have reason to believe, a lesser parallel anticlinal
axis, the cause, indeed, of the elevation of the limestone along
this line. Between it and the main axis, a little southeast of
Swartwout’s Pond, ali the rocks have a synclinal arrangement,
the belt of slate lying in the middle of the trough of the limestone.

Tracing the principal axis of the Paulinskill Valley beyond
the termination of the limestone near Courserville, we find it run-
ning for several miles further towards the northeast, until it passes
a. little west of Deckertown, elevating the beds of the slate.

The limestone valley of the Paulinskill corresponds accurately
in its general physical features with what is termed a valley of
elevation.

Its strata having been upheaved along a central anticlinal axis,
the surface of the valley is somewhat raised in the centre, and
depressed along both margins, while the overlying and surround-
ing strata of slate, less broken and denuded than the limestone,
encompasses it in a regular escarpment, giving to the whole the
true structure of a valley of elevation.

A much broader zone of slate is interposed between the
Paulinskill axis and that of the Newtown Valley, than between this
latter and the axis of the Jenny Jump and Pochuck range. This
is obviously the result of a twofold cause, the greater interval
which separates the two northwestern axes, and the less amount
of vertical elevation in the strata adjoining them: leaving, there-
fore, both a broader and deeper synclinal trough in the slate
to resist the denuding agency of the currents, which have swept

61

off so large a portion of the upper strata from the Kittatinny
Valley. Between Belvidere and Columbia, on the Delaware, the
tract of slate, which is here several miles in breadth, exhibits
numerous local changes of dip, the result probably of a series of
lesser anticlinal axes, which may traverse this end of the belt.
The oblique cleavage planes are so conspicuously displayed in this
part of its range, as to efface, very generally, all distinct traces
of the true stratification, rendering the determination of its axes a
work of extreme uncertainty. The simple synclinal structure of
this belt opposite Newton and Augusta may, however, be readily
established by a close attention to the true dip of the rocks.

Only two other ranges of the lower Appalachian limestone,
besides those already referred to, occur within the State. These.
are, the belt traversing German Valley and its extension, and the
small patch in the valley of Mendham. Both of these have been
previously adverted to, as occurring in the form of narrow syn-
clinal basins, included between the adjacent ridges of the primary
rocks. The upheaving of these latter, by a series of axes of
elevation difficult to trace in detail, has manifestly given to the
limestone its synclinal posture in the intervening valleys, where
this rock obviously once spread itself over much wider tracts than
at present.

Igneous Rocks connected with Formation IT.

Of the changes induced upon the limestone by igneous action. —
The blue limestone of the Kittatinny Valley exhibits, in certain
localities, some highly impressive and remarkable phenomena of
alteration of structure, induced by the heating agency of a series
of igneous injections. The altered bands of the rock may be cor-
rectly grouped into two distinct belts, ranging from northeast to
southwest, parallel to the general strike of all the strata in this
quarter of the State. The more northeastern of these belts oc-
cupies, at intervals, the valley which lies immediately at the foot
of the Hamburg or Wallkill Mountain, throughout nearly its
whole length, keeping usually towards its northwestern margin,
or near the base of the Pochuck Mountain, and the belt of hills
in its prolongation to the southwest, namely, the hills north of

6

62

Franklin, Pimple Hill, and the hills north and west of Sparta
and Lockwood.

That further to the southwest commences at the northeastern
extremity of Jenny Jump, and follows the southeastern base of
this mountain throughout nearly its whole length, beyond which,
after an interruption of about two miles, it again occurs near
Oxford; and further still, at intervals, near Concord and David-
son, where it is within two miles of the Delaware. ‘Traced lon-
gitudinally, the altered rock shows itself not so much in one con-
tinuous line, as in a succession of long, narrow, and somewhat
detached belts, several of which sometimes lie parallel to each
other and closely contiguous.

The northeastern tract first shows itself at Mounts Adam and
Eve, in New York, about five miles beyond the state line, and
has its southwestern termination in the neighbourhood of Lock-
wood. Over this whole distance, though the altered material
exhibits considerable diversity in regard to the imbedded minerals
which it contains, yet the main mass of the rock, or the calca-
reous paste investing them, retains to a. great extent, a uniform
character as to colour and structure.

When destitute, or nearly so, of the extraneous minerals
often diffused through it, the prevailing condition of the rock
is that of a white, perfectly crystalline limestone. An extreme
degree of developement of the crystalline structure, is when the
mass had assumed the condition of rhombic calcareous spar.
It is then often semitranslucent, but more frequently it is of an
opaque white, and occasionally of a pink hue, resembling some-
what reddish felspar. ‘These varieties may be regarded as the
altered rock under its most characteristic features, and are to be
viewed as exhibiting the /imit of alteration of which the limestone
has been susceptible by igneous action, where it has been pure, or
consisted of little else than carbonate of lime. When of such
aspect and structure, the mineral most usually disseminated
through it is plumbago, in small brilliant plates, often perfectly
hexagonal. Besides this highly developed crystallization, it pre-
sents every gradation of crystalline structure down to a finely
granular one, and even to what may be termed the suberystal-
line condition, when it often partakes of the colour and texture
of the blue limestone, out of which all these varieties have origi-

63

nated. Clouded, veined, and spotted, by various mineral matters
mingled through it, and frequently susceptible of an excellent
polish, it promises to furnish, if attainable in masses of suflicient
size, a material of superior beauty for ornamental purposes in archi-
tecture. Various foreign minerals blend themselves occasionally
through the substance of the calcareous rock in every possible
proportion, from a few sparse crystals to such an abundance as
almost to replace the calcareous matter, which then merely fulfils
the part of a cement.

These minerals, several of which are rare in the cabinets of
the mineralogist, constitute a list, when all are enumerated, of con-
siderable extent. Those which chiefly predominate, and which
tend by their prevalence to impart a certain uniform mineral
character to the altered limestone, are: Condrodite, or Brucite,
in orange-yellow crystals; augite, common and crystallized ;
plumbago, foliated usually in six-sided scales; spinelle, often in
octohedral crystals; sahlite, and mica.

The following catalogue, by Dr. Fowler, of Franklin, who has
zealously contributed to draw the attention of mineralogists to this
interesting region, exhibits a sufficiently detailed list of the mi-
nerals hitherto discovered in association with the altered lime-
stone:

“ Franklinite—A new metalliferous combination, containing,
according to Berthier, of oxide of zinc 17, of iron 66, and man-
ganese 16 parts, is very abundant, indeed it appears inexhaustible.
It commences about half a mile northeast of Franklin Furnace, and
extends two miles southwest of Sparta, a distance of nine miles.
It is accompanied in this whole distance by the red oxide of zinc,
mutually enveloping each other. The greatest quantity appears
to be at Franklin Furnace. ‘The bed here is about one hundred
feet high above the adjoining land, on the west side of it, and
from ten to forty feet wide. Various attempts have been made
to work this ore in a blast furnace, but without success. It fre-
quently congeals in the hearth before time is allowed to get it out
in a liquid state, in consequence of a combination of the iron with
manganese. ll this difficulty, I apprehend, might be overcome,
if a method could be discovered of smelting iron ore in a blast

64

furnace with anthracite coal; as the Franklinite requires a greater
degree of heat to cause it to retain its liquid state, than can be
obtained by the use of charcoal. It occurs in grains, imbedded
in the white carbonate of lime, and detached in concretions of
various sizes, from that of a pin’s head to a hickory nut; also in
recular octohedral crystals emarginated on the angles, small at
Franklin, but very perfect, with brilliant faces. At Sterling, the
crystals are large and perfect. I have one from that place that
measures sixteen inches around the base.

«“ Red Oxide of Zinc.—At Sterling, three miles from Franklin,
a mountain mass of this formation presents itself about two hun-
dred feet high. Here, as Mr. Nuttall truly observes, the red
oxide of zinc forms, as it were, a paste, in which the crystals of
Franklinite are thickly imbedded; in fact a metalliferous por-
phyry. This appears to be best adapted for manufacturing purposes.
The Franklinite imbedded in the zinc ore here, is highly magnetic,
and may be all separated by magnetic cylinders, recently brought
into use to separate the earthy portion of magnetic iron ore. It
was long since observed, that this ore is well adapted for the ma-
nufacture of the best brass, and may be employed without any
previous preparation. It is reduced without any difficulty to a
metallic state, and may be made to furnish the sulphate of zinc
(white vitriol.) Berthier found it to contain oxide of zinc 88, red
oxide of manganese 12.

“ Magnetic Iron Ore.-—On the west side of the Franklinite, and
often within a few feet of it, appears an abundance of magnetic
iron ore, usually accompanied by hornblende rock. In some
places it soon runs into the Franklinite, which destroys its useful-
ness; and the largest beds are combined with plumbago, which
renders it unprofitable to work in a blooming forge, but valuable
in a blast furnace.

“The other minerals found in this district are numerous, rare,
interesting, and several of them new, and not found in any other
place, but better calculated to instruct the naturalist and adorn
his cabinet, than for any particular uses to which they have as
yet been applied. A catalogue which I have subjoined, designates
the minerals as they occur in each township.

“In Byram Township, considered the southwestern extremity

65

of the white carbonate of lime, occur: Spinelle, colour reddish-
brown, green, and black, in octohedral crystals, associated with
orange-coloured Brucite. Brucite of various shades, from that
of a straw-colour, to dark-orange, and nearly black. Gray horn-
blende, in six-sided prisms, with dihedral summits.

“In the Township of Hardiston.—At Sparta: Brucite of a beau-
tiful honey-colour: the finest we have is found here. Augite, in
six-sided prisms; colour brownish-green.

“ At Sterling —Spinelle, black, green, and gray, in octohedral
crystals. Brucite of various shades. Rutile; colour steel-gray ;
lustre metallic, in acicular prisms, with longitudinal striae. Blende,
black and white; the white sometimes in octohedral crystals, the
lustre brilliant. Dysluite, in octohedral crystals; colour brown
externally ; internally yellowish-brown; lustre metallic (a new
mineral). Ferruginous silicate of manganese, in six-sided prisms,
colour pale-yellow ; associated with Franklinite. Tourmaline, im-
bedded in white felspar, in six-sided prisms; longitudinally stria-
ted; colour reddish-brown. Green and blue carbonate of copper.
A number of large excavations were made at the Sterling Mine
for copper, during the revolutionary war, under an erroneous
impression, that the red oxide of zinc was the red copper ore. It
was the property of Lord Sterling ; hence the name of the Sterling
Mine. Of copper, we only find there a trace of the green and
blue carbonate,

“ At Franklin.—Spinelle, black and red crystallized. Ceylonite,
green and bluish-green, in perfect octohedrons, truncated on the
angles; lustre of the brilliance of polished steel. Garnets, black,
brown, yellow, red, and green, crystallized in dodecahedrons.
Silicate of manganese, light brownish-red. Ferro-silicate of man-
ganese, of Professor Thompson, and the Fowlerite of Nuttall, light
red or pink, foliated and splendent; has much the appearance
of felspar; is also in rectangular prisms. Sesqnisilicate of man-
ganese, lamellar in scales or small plates; colour brownish-black.
Hornblende, crystallized. Actynolite, crystallized. Tremolite,
crystallized. Augite, common variety, crystallized. Jeffersonite,
common variety, crystallized. Plumbago, foliated and crystallized
in six-sided scales. Brucite of various shades. Scapolite, white,
crystallized. Wernerite, yellow, crystallized. Tourmaline, black,

6*

66

crystallized. Fluate of lime, earthy and crystallized. Galena.
Oolite, in small grains about the size of a mustard-seed, dissemi-
nated in blue secondary carbonate of lime. Asbestus, connected
with hornblende rock. Green beryl. Felspar, green and white,
erystallized. Epidote and pink carbonate of lime. Arsenical
pyrites. Serpentine. Sahlite. Cocolite, green and black. Sphene,
honey-colour, crystallized. Quartz. Jasper. Chalcedony. Ame-
thyst crystallized. Agate. Mica, black and orange-coloured,
crystallized. Zircon, crystallized. Sulphate of Molybdena. Phos-
phate of iron. Carbonate of iron. Steatite, foliated, with yellow
garnet. Phosphate of lime crystallized. Pale yellow blende, of a
foliated structure, lustre, vitreous.

“ Near Hamburgh.—An ore of manganese and iron, of a light
reddish-brown, very compact and heavy. Augite and Brucite.

“In the Township of Vernon.—Green spinelle and Brucite, in
octohedral crystals.

“In Newton Township.—Sulphate of barytes in lamellar masses,
and tabular crystals, in a vein traversing secondary limestone.
Sapphire, blue and white, in rhombs and six-sided prisms. Red
oxide of titanium. Gray spinelle in large octohedral crystals.
Mica, copper-coloured, in hexahedral crystals. Idocrase, crys-
tallized, yellowish-brown. Steatite, presenting the pseudomor-
phous form of quartz, scapolite, and spinelle. Scapolite, in four-
sided prisms.

“For a more particular account of the Newton minerals, see
Silliman’s Journal, vol. xxi. page 319.

“In Frankford Township.—Serpentine, of a light yellowish-
green, bears a fine polish, has a glistening lustre, and is quite
abundant.”

On the Franklin or Warwick mountain, about four miles east
of the furnace, are numerous beds of iron ore, from which many
thousand tons have been taken; and which still contain a large
quantity of the best quality of ore, either for a blooming forge or
blast furnace. [ron pyrites occurs here, both in the valley and on
the mountain, of a proper quality to manufacture sulphate of iron
(copperas). It also occurs crystallized, in cubes, in octahedrons,
and dodecahedrons, frequently perfect and highly splendid.

67

Following the range of the crystalline limestone somewhat
more in detail, we shall commence our description of its geologi-
cal features where it first conspicuously shows itself, in the neigh-
bourhood of Amity, in New York. Here, and for several miles to
the southwest, the belts of altered rock occupy a very considerable
width, in the valley ranging from Mounts Adam and Eve towards
Hamburg, forming a zone averaging, at first, half a mile in breadth,
but contracting to two or three hundred yards. The crystalline
material in its most perfect form, does not, however, fill the whole
space, but occupies rather a series of closely adjacent parallel
bands, most numerous towards the middle and northwestern side
of the valley, where a chain of low irregular ridges usually con-
tain the limestone in the highest state of crystallization. These evi-
dently mark the existence of a series of parallel veins of igneous
origin, the intrusion of which into the limestone, have obviously
caused its alteration. Between the base of the Wallkill Mountain
and the crystalline rock towards the middle of the valley, we
usually meet with beds of the formation which evince but a par-
tial amount of change from the igneous action; the limestone
retaining more or less of its bluish tint, and presenting only a sub-
crystalline, or even the ordinary earthy, texture. These less al-
tered beds, reposing upon the gneiss of the Wallkill Mountain, dip
towards the northwest. ‘Towards the base of the Pochuck Hill,
on the other side of the valley, the limestone would seem to have
undergone a more extensive alteration. Approaching Hamburg,
the crystalline belt contracts considerably in width. About two
and a half miles northeast of that village, we find it occupying a
breken chain of long, narrow, irregular ridges of considerable
elevation. ‘These range parallel with the base of the Pochuck
Mountain, separated from it by a tract of low meadow ground,
about three hundred yards in breadth. In this belt the altered
limestone is in great confusion; the calcareous crystalline matter
being mingled largely, in many places, with a white friable sand-
stone, referable, obviously, to Formation I., the position of which,
when it occurs at all, is immediately beneath the limestone.
The fused calcareous matter seems in some cases to have pene-
trated the substance of the sandstone. ‘The height of this ridge or
chain of ridges may be stated to average about two hundred feet ;

68

the width at the base being not less than a fourth of a mile, and the
length rather more than one mile. Besides the mass of altered
limestone, these ridges comprise portions of Formation I., toge-
ther with beds of the gneiss, both in a highly disordered and shat-
tered condition, with more than one extensive dike of igneous
matter, the immediate cause, most probably, of these disturbances.

From the confusion which accompanies all these rocks, none
of them can be found, even for a short distance, possessing any
regularity of dip.

The gneiss rocks of the Pochuck Mountain, on the contrary,
are distinctly seen dipping steeply towards the valley to the
southeast.

The most conspicuous display of the crystalline limestone is at
the two extremities of the ridge which lie nearest Hamburg.
Between these points, towards its central portion, the same ridge
contains a large well-known deposit of brown or hematitic iron
ore, occupying its summit and sides, and penetrating deeply into
the body of the hill; details regarding this valuable iron mine
will be given under another head.

Separated from the Hamburg belt of altered limestone, by a
spur of the Wallkill Mountain, ities exists another band of the
crystalline rock on the Sand Pond creek, about one mile and three
quarters southeast of Hamburg. This commences near the south-
western termination of a small knob of gneiss.

Though highly crystalline, the limestone still retains consider-
able regularity of stratification, dipping towards the west-north-
west, at an angle of 20°, being well exposed in a quarry, (the
property of Wm. Edsall,) where it is used for making pure lime.
It is white, and highly crystalline, and contains disseminated
scales of graphite. This line of altered rock ranges south-west-
ward nearly to the turnpike, and is met with again on the road
to Sparta, about half a mile beyond the turnpike.

Between the small knob of gneiss, above spoken of, and the
Wallkill Mountain, to the southeast, we meet with another depo-
sit of brown or hematitic iron ore, a little beyond the termination
of the crystalline limestone, none of which, however, is discovered
near it. This ore will be more minutely described in another
place.

69

To the northeast of this altered belt we trace another, occupy-
ing the northwestern side of the Mine Hill, east of the Wallkill
stream, a long narrow point of primary rocks, extending from
Pimple Hill to within about three miles of Hamburg. Not far
from the northeast termination of Pimple Hill, and near the old
Franklin furnace, we encounter, in the northwestern side of the
Mine Hill, next the valley of the Wallkill, a narrow belt of com-
mon gneiss rock, dipping, as usual, to the southeast. Reposing
upon this, with a conformable dip, is seen a highly interesting
mineral vein composed of impure magnetic iron ore, Franklinite,
Garnet, Jeffersonite, and several other crystalline minerals, blend-
ed, especially near the borders of the mass, with the crystalline
limestone, much darkened and changed from its ordinary appear-
ance, by the amount of combined mineral matter; much of this
calcareous portion of the vein is pervaded by small granular
crystals of the Franklinite. The whole vein has a thickness of
several feet.

Immediately east of this metalliferous vein, there rests, in the
main body of the hill, a broad belt of the white crystalline lime-
stone, preserving its original, rather steep, southeastern dip. The
position of the vein here, is therefore, as in the majority of in-
stances in the region, intermediate between the primary strata
and the beds of altered limestone, which, notwithstanding the
partial fusion and intense heat to which it has been subjected, still
furnishes distinct traces of its lines of deposition.

Towards the eastern declivity of the hill, the crystalline rock
prevails in considerable purity, though it is often very free from
foreign admixtures, even adjacent to the metalliferous vein. In
this latter position, however, it is more frequently mixed with
quartz, felspar, sahlite, augite, hornblende, and a great variety of
minerals, some of which are common ingredients in the primary
strata of the country. In the quartz, and near its contact with
the limestone, green spinelle occurs.

The occurrence of so many of the minerals which are constitu-
ents of the adjoining primary rocks, both in the intrusive vein itself,
and in the neighbouring portions of the altered limestone, is a fact
of no little theoretical interest, as it leads us directly to views tend-
ing to explain satisfactorily the several sources of the numerous

70

and varied crystalline minerals found connected with the changes
effected in the limestone.

At the summit of the ridge there is a seam of quartz rock, pre-
senting some indications of its occurring as a vein in the white
limestone. Its nature and origin cannot be proved, for it may be
a vein of mineral matter strictly intrusive, or one of the beds
of chert, so common in the limestone, or a portion of Forma-
tion I., completely fused by contact with the intensely heated
metalliferous vein. The confused arrangement and varied aggre-
gation of the altering and altered materials at this place, render it
next to impossible to trace the true relationship subsisting between
some of the parts comprised in this curiously heterogeneous belt of
mineral matter. The vein, in its course to the southwest, under-
goes a considerable change in its character. About two hundred
yards southwest from the place already mentioned, it appears to
consist almost wholly of garnet rock and Jeffersonite, some of the
latter occurring in enormous crystals, projecting from the face of
the rock, but so fissured and readily broken as to render it diffi-
cult to procure them entire.

Further still to the southwest, and nearly opposite the Old
Forge, are considerable excavations made in former times for
iron ore. The ore was far from pure, abounding in Franklnite ;
which by the manganese and zinc contained in it seriously inter-
fered with the conversion of the ore into iron. This ore includes,
moreover, a considerable proportion of the red oxide of zinc, in
some places remarkably pure, being finely lamellated and un-
associated with any of the Franklinite that generally accompanies
it, and which interferes effectually with its reduction into metallic
zinc on the large scale.

Could this pure red oxide be obtained in sufficient quantity, it
would probably be better adapted for smelting into zinc than the
mixed ore of the Sterling Mine, three miles further to the south-
west. This somewhat rare ore of zinc, the crystallized red oxide,
occupies, in company with the crystallized Franklinite, a metal-
liferous vein, or more probably a line of nearly continuous veins,
in the crystallized carbonate of lime, extending, with occasional
interruptions the whole distance from Franklin to a little beyond
Sparta, a total length of more than eight miles. _

vf

The catalogue already presented, compiled by Dr. Fowler of
Franklin, supplies a nearly complete list of the other minerals
found in this part of the igneous and altered zone of rocks.

From Franklin we may trace the white crystalline limestone
continuous to Sterling, about three miles to the southwest.

Here we find it lying in contact with a remarkable vein
consisting exclusively of Franklinite and the red oxide of zinc;
the former in crystalline granules, often approaching the ochto-
hedral form, invested by a paste of the zinc ore, which frequently
constitutes more than one-half of the mass. The position of this
vein is on the eastern declivity of a hill of considerable elevation,
where it occupies the same intermediate relation to the gneiss
and crystalline limestone which was mentioned of the vein at
Franklin.

At Sterling, the metallic vein, where it is visible at the surface,
rests with a steep southeast dip conformably upon the steeply-
dipping beds of gneiss, rising in the form of a bold cliff or wall
along the side of the hill. Against this wall of ore, and at the
base of the hill, repose the beds of the white altered limestone,
presenting unequivocal traces of its original planes of stratification,
showing the sedimentary origin of the rock. It obviously dips
at the same inclination of from 70° to 80° to the southeast, with
the vein and the gneiss upon which it lies.

The metalliferous vein is from eight to ten feet in thickness,
and consists of no other minerals but the Franklinite and ore of
zinc. From its exposed position on the flank of the hill, the ore
could be excavated to an almost indefinite extent with a facility
unusual in the history of mining operations. Zinc of an admirably
pure quality has been prepared from this ore by Mr. Hitz, under
the directions of Mr. Hasler, for the manufacture of the brass
for the standard weights and measures now making by the latter
scientific gentleman for the several custom-houses of the United
States, by order of Congress. An economical method for the
separation of the zinc from the Franklinite in this ore, still
remains, however, a desideratum in practical metallurgy.

Between Sterling and Sparta, the belt of crystalline limestone
is traceable with but little interruption nearly the whole distance,
affording in some places specimens of a variegated marble of

72

uncommon beauty. It follows the eastern base of Pimple Hill to
the southwestern termination of that ridge, and then appears nearly
in the same line at several points on the west of the gneiss hills,
west of Sparta, and also within a few hundred yards of the
town itself. The narrow valley embraced between those hills
and the Wallkill Mountain on the southeast, is in the immediate
neighbourhood of Sparta, and for some distance southwest,
occupied by the unaltered blue limestone dipping usually towards
the northwest.

About a third of a mile northwest of Sparta, the white crystal-
line limestone crosses the turnpike road. ‘This is one of the prin-
cipal localities whence mineralogists have supplied their cabinets
with specimens of condrodite or Brucite. A better locality, how-
ever, may be seen on the west side of the hill, about half a
mile further north, where another exposure of the white crystal-
line limestone affords crystals of the Brucite and gray spinelle in
an abundance and of a quality far surpassing those of any other
spot yet discovered in this vicinity. At the same place might be
opened inexhaustible quarries of variegated and pure white mar-
ble; some of the former promising to be, if polished, of uncommon
beauty. Care should be observed, in establishing quarries in this
rock, to choose those parts of the belt least shattered by the
action to which it has been exposed.

Between three and four miles southwest from Sparta, on the
northwest side of a low ridge of gneiss, we find a very interesting
locality of the altered limestone, very nearly in the prolongation
of the belt which passes along the southeast base of Pimple Hill.
This spot is remarkable less for the extent or breadth over which
the limestone has been affected by igneous action, than for the
strikingly convincing evidence which it affords of the nature of
the changes induced in the calcareous rock by the series of ig-
neous veins and dykes which we have been tracing. The ridge
itself, along the side of which the limestone has been altered, con-
sists chiefly of a thinly-bedded micaceous gneiss. Through the
summit, or rather on the northwestern flank, which is often ab-
rupt and rugged, there rises a thick granitic dyke or vein of very
heterogeneous composition, supporting the steeply-dipping beds
of gneiss, whose usual inclination is at an angle of 80° to the

73

southeast. The vein, though various in character, and somewhat
difficult to describe, owing to the imperfectly developed nature of
its minerals, and their complete interfusion, may be characterized
as consisting, in the main, of mica in large excess, quartz, carbonate
of lime, felspar, and augite. It contains spinelle, sapphire, and
green talc, besides several other minerals less distinctly crystal-
lized.

When we consider the highly micaceous character of the adja-
cent gneiss rock, through which the matter of the vein must have
passed in reaching the surface, and the abundance of the mica,
especially of the brilliant golden variety, found so plentifully not
only in it, but in the adjacent parts of the altered limestone, we
cannot resist the impression, that a portion of the primary strata
along the sides of the dike, have been melted and incorporated
into it, floating, in combination with the other materials, to the
surface.

Immediately upon the western side of this curious vein, and
ranging along the base of the hill, occurs the narrow belt of
altered limestone. The gradation of change which here exists
between the blue and earthy limestone, and the white crystalline
rhombic spar, is distinctly traceable as we approach the igneous
dike. Ina breadth not exceeding fifty feet, we discover every
degree of modification which the rock can undergo by heat. The
first intimation which the limestone gives us of its having been
subjected to the igneous agency, is its passage from the ordinary
earthy texture to a subcrystalline one. We next behold a slight
change of colour to a lighter tint of blue, and, at this stage of
alteration, we notice the first developement of the graphite, as yet
seen only in small but very brilliant scales, which are oftentimes
hexagonal. Very soon the mass becomes mottled with white,
minutely granular carbonate of lime, the spangles of graphite
growing progressively larger. Approaching still nearer to the
dike, the whole rock assumes the white sparry character, and
contains, near the line of contact, besides the graphite, several of
the numerous crystalline minerals of the vein itself. So completely
has the injected matter of the vein been mingled, in many places;
with the fused substance of the limestone, that no distinct line of
demarcation is discernible between them.

a

74

The series of changes here described may be considered as
representing the phenomena in every instance, where superficial,
deposits have not concealed the vein, the blue limestone, and the
intermediate altered belt. The locality above referred to is dwelt
on in detail, chiefly because it furnishes a distinct exhibition of
each successive stage of the change. ‘The gradation is not more
complete at this place than near many other dikes, but it is
better exhibited within a small area.

The invariable occurrence of the graphite, in portions of the
altered belt remotest from the dike, and its never existing in
more than a very trivial quantity, even adjacent to the vein where
the other extraneous minerals are frequently present in great
excess, strongly imply that it has been derived from the elements
of the blue limestone itself, which may easily be proved to contain
an adequate quantity of iron and carbon for the production of this
mineral.

It is not a little curious that, in some belts, the altered rock
contains the mineral condrodite, in a precisely similar relation as
to the degree of crystallization of the mass, and proximity to the
vein of igneous matter; that is to say, when it first appears in the
portions of the crystalline belt remotest from the line of injected
minerals, it is in small imperfectly developed nuclei, which grow
larger and better formed as we approach the quarter of more
intense igneous action, but which, like the crystals of graphite,
usually remain but sparsely disseminated through the rock.
Showing a strong analogy, in its mode of distribution through the
substance of the white limestone, to the nuclei or geodes of epr-
dote and other minerals seen in the red shales where these have
been baked and altered by the intrusion of dikes of heated trap,
the condrodite seems to claim a corresponding origin to that gene-
rally attributed to the epidote, which is regarded as derived, in
these cases, from the constituents of the rock itself. To trace the
source of the condrodite upon this hypothesis, we have only to
conceive that the injected mineral matter, in an igneous state,
was poured through fissures in a limestone, possessing, what is
very common, a siliceo-magnesian character; and the well
known tendency to the production of specific mineral combina-
tions, in a mass whose particles are ina state of at least semi-

75

fusion, and, therefore, free to obey their several ‘affinities, will
readily explain the formation of these insulated crystalline nuclei.
The mineral condrodite contains about 54 per cent. of magnesia,
with about 38 per cent. of silica, besides trivial propurtions
of oxide of tron, potash, fluoric acid, and water. These sugges-
tions, respecting the origin of the condrodite, receive support from
the fact, that this mineral prevails in its usual uniform and mode-
rate proportion through considerable ranges, longitudinally, of the
altered limestone, even where not immediately contiguous to the
injected veins, while in other parallel zones of the crystalline
rock it is almost wholly absent. Thus, in the chain of sparry
limestone which stretches at intervals from Sparta towards
Lockwood, we find it almost constantly present, though never
but in moderate quantity.

From several chemical analyses of the sparry, rhombic varieties
of the rock containing only graphite, and of the white irregularly
crystalline kinds enclosing the condrodite, we have still more
conclusive evidence tending to settle this interesting point.

Resuming our progress towards the southwest, we next meet
with a succession of detached ridges of the altered sparry lime-
stone, in the valley between the Wallkill Mountain and the
primary ridges southwest of Sparta; the latter tract of gneiss
separating this belt from that previously described. These ridges
first appear nearly four miles southwest of Sparta, at the ex-
tremity of an extensive meadow, and range towards Lockwood.
They are four in number, the shortest being about one hundred
yards long, while the longest exceeds a fourth of a mile. ‘Their
width is between two hundred and three hundred feet; they
occupy one general line; but between their extremities is usually
a space of from half a mile to a mile of primary strata, whose
prevailing dip is towards the southeast, though under circum-
stances of great irregularity.

The white altered limestone of these ridges is rather in the
condition of an amorphous crystallization, than in the form of
rhombic spar. Such is the case at Franklin and Lockwood. It is in
fact a coarse granular white marble imbedding many of the rare
and beautiful crystalline minerals found at Amity and Franklin;
we may mention Brucite and green spinelle of uncommon purity.

76

Notwithstanding the prodigious extent of igneous action to
which the limestone has been evidently exposed in these belts,
manifested by the width of the space over which a total modi-
fication of the rock has been effected, we still discern a very
distinct stratification, the beds dipping steeply towards the south-
east.

In the same line with this series, and about one mile and a half
further to the southwest, occurs another somewhat shorter belt of
the altered limestone, a little beyond Lion Pond. The length
throughout which the limestone has been modified, does not
exceed two hundred or three hundred feet, and the width of the
belt is not considerable. The locality is nevertheless an in-
teresting one, for we find well exposed, within a tract not more
than a fourth of a mile wide, first, the primary strata on the
southeast, then the sandstone, F. I., next the blue limestone, F.
II. passing into the sandstone, and assuming near the passage
a clear reddish hue, and lastly, the belt of altered limestone in
contact with a small elevated hill or dike of felspathic sienite,
the cause of the altered structure of the calcareous rock. All of
these stratified masses, the gneiss, the sandstone, the blue limestone,
and the white crystalline belt, dip alike towards the northwest at
a gentle inclination.

Graphite is here present as usual in the calcareous mass ;
which besides contains other minerals.

Portions of the altered rock are coarsely crystalline, though
other parts of it are more minutely granular. A variety which
is variegated with numerous blue shades of plumbaginous mineral,
might evidently, from its susceptibility of a good polish, be em-
ployed as an ornamental marble.

Between the sienitic ridge here spoken of and another lying a
short distance to the north, there occurs another smaller belt of
the altered limestone, deeply buried between the primary rocks.
At this spot some enthusiast in search of mineral treasures,
expended at a former day no inconsiderable amount of time and
labour, in excavations for silver ore in the sparry limestone.

West of the last mentioned point may be seen, by the side of
Panther Pond, another still more unimportant exhibition of the
altered sparry rock, not deserving of a special description.

77

Near Lockwood, not far out of the general line of the larger
belts or ridges of the crystalline limestone already treated of, we
come upon another band of the calcareous rock which has
undergone alteration. Though of rather local extent, this spot
is deserving of attention, if only for the perfection in which we
here behold the translucent rhombic spar, into which the blue
sedimentary limestone has been converted by the agency of heat.
Disseminated through the spar, we find the graphite sometimes
in regular hexagonal plates half an inch in diameter. From a
large rhombic crystallization, the calcareous rock graduates to
an amorphously crystalline limestone, or a white granular marble.

Some portions of. the mass, especially those having the more
highly developed crystalline character, include, besides the
graphite, several minerals, as Brucite, mica, talc, quartz, and green
spinelle ; the mica being in some cases so abundant, as to imply
probably its derivation from the contiguous gneiss rocks.

While alluding to the vicinity of Lockwood, it may be men-
tioned as an interesting locality of granular and crystalline augite.
Some of the beds of the gneiss in this neighbourhood, being
traversed by bands of a deep-green talcose mineral, pervading a
mass consisting chiefly of lighter-coloured felspar, would furnish
a building material of very beautiful appearance.

Having now described in sufficient detail the numerous bands
of altered limestone comprehended in the one general belt of
igneous action, which stretches in a nearly straight direction
from beyond Amity, in New York, to its southwestern termination
near Andover Forge, a little beyond Lockwood, I shall in the
next place enter upon a more brief account of the shorter, but
no less interesting belt, which pursues the southeastern base of
Jenny Jump.

As in the instance of the altered rock near the eastern foot of
Pochuck Mountain, the beds of the white crystalline limestone of
Jenny Jump do not lie against the flank of the hill itself, but
belong to a separate low narrow ridge, or rather series of ridges,
parallel with its base, but at a distance sometimes of a few
hundred feet. These ridges consist in part of the altered rock,
and in part of a succession of intrusive dikes of what, from its
general aspect and composition, may be termed a sienite rock,

7%

78

but which contains, besides the ordinary ingredients, various
other minerals, as epidote, serpentine, indurated talc, compact
steatite, and jade. In some places the white limestone is wanting,
having been evidently removed by denudation, as indicated by
the rolled fragments occasionally met with in the adjoining
plain. But even where it is absent, we observe the usual narrow
ridge with its peculiar dike of heterogeneous mineral matter.

Towards the northeastern end of the belt, about two miles
southwest of the road which leads to Long Bridge, the road
parallel with the base of the mountain runs in a little narrow
strip of meadow between the dike, which here shows a nearly
vertical wall, and a second parallel small ridge, rising imme-
diately on the southeast, and which is composed of the sparry
limestone and altered chert, dipping at the steep inclination of
80° towards the southeast. The ridge on the northwest of the
road, containing the dike, would seem to include, besides a bed
of the altered limestone, having a distinct dip at this spot to the
north-northeast of 70°, several magnesian rocks, as serpentine,
greenish jade, Saussurite, and indurated talc.

The primary rocks in this vicinity, in the base of Jenny Jump,
display marks of the most violent disruption and compression of
their strata, exhibiting an unusual number of intrusive dikes and
veins, in which, as in those immediately affecting the limestone,
we notice a remarkable diversity of mineral composition. The
constitution of the dike, or chain of dikes, directly in contact
with the altered limestone, though variable, is essentially different
from that of the igneous veins disturbing in a parallel line the
primary strata at the base and on the side of the mountain, being
characterized by a predominance of the minerals of the magne-
sian class.

We have evidence that the limestone at one time spread itself
extensively along the base and slopes of Jenny Jump; for, not
only do we find, on the sides and even summit of the mountain,
scattered blocks of the stratum and its included chert in consi-
derable number and size, but we observe traces of its having
undergone fusion and incorporation with the materials of some of _
the dikes and veins before alluded to, at the southeastern foot of
the mountain. Though the white sparry rock is no longer visible

79

there in mass, its materials, both the carbonate of lime and the
commonly prevailing graphite and condrodite, are frequently min-
gled in variable proportions with the minerals of the intrusive
veins. This incorporation of the altered products of the blue
limestone, its calcareous spar and its graphite and condredite, is
much more intimate and more extensively seen in the ridges to
the southeast, where the regular belt of the altered rock in
contact with the igneous vein has resisted denudation.

Northeast of the locality to which the above descriptions have
been principally confined, the belt of white crystalline limestone
runs for a distance of between two and three miles, forming in
some places a tract of considerable breadth. In some portions of
the line the altering rock is a dike of greenstone, of a close grain
and extreme toughness and density.

About two miles to the southwest of the place first mentioned,
and near the road which crosses the mountain going from Hope
towards Hacketstown, we cross the crystalline limestone at a
point about a mile to the west of the little village of Danville, not
far from the southwest extremity of the Great Meadow. At this

locality the rock has assumed a somewhat unusual colour and
aspect; the carbonate of lime, which chiefly constitutes the mass,
being in the condition of rhombic spar, whose tint very much
resembles that of ordinary reddish felspar. The presence, in
some parts of the rock, of numerous small crystals of greenish
augite, with occasional scales of graphite and even of dark mica,
impart to the whole mass a very marked resemblance to certain
varieties of granite, in which a pink felspar is the prevailing
mineral. An inattentive glance at the rock will leave the travel-
ler deceived as to its nature.

The igneous actions affecting the limestone, display their ordi-
nary phenomena at intervals for several miles still further towards
the southwest.

A small belt of the crystalline rock is traceable in the prolonga-
tion of the general line, occupying a spot a little to the southwest
of the small lake called Green’s Pond, and not far from the southern
termination of Jenny Jump.

We again find it in the same range along the northwest base
of Scott’s Mountain, in two unimportant bands, the last which
we discovered in the State. One of these occurs between the

80

little villages of Oxford and Concord, and the other still further
to the southwest, near Davison’s Mill, which brings us to within
one mile of the Delaware river.

I have been thus full in describing the singular phenomena of
induced crystallization, caused in the limestone by igneous agency,
and in endeavouring to trace to their several sources the various
extraneous minerals which accompany the alteration, from a
persuasion of the interesting relations of the whole subject to the
important doctrine of the metamorphosis of rocks.

The great thickness throughout which the limestone has under-
gone a most thorough crystallization from the heating agency of
the dikes which traverse it, and the curious law traceable in the
developement of some of the minerals, which appear in the light
of segregations from elements contained in the limestone, afford
unquestionably strong support to the theory, which assumes that
gneiss and other primary strata have once been sedimentary
rocks, converted by an extremely intense and wide spread igneous
action into a universally crystalline state.

Respecting the question of the probable date at which the
mineral injections occurred, which have so singularly modified
the structure of the adjacent limestone, we can merely hazard
some general conjectures, which rest rather upon analogies than
upon a foundation of facts,

Economical Relations of F. I.

Perhaps of all the rocks in the State, the formation whose
geological structure we have now described, is that which is
most extensively and variously applicable to the useful purposes
of life.

(a.) Among its several important uses, we may advert, in the
first place, to its adaptation as a bualding stone. The great
readiness with which it may be quarried, the facility with which
it may be shaped and cut, its agreeable colour, and, above all,
its strength and almost perfect indestructibility by atmospheric
agents, unite to recommend it in the construction of dwellings,
barns, public edifices, and the structures connected with civil
engineering, such as locks, bridges, and aqueducts. Lamentable
inattention, however, is frequently displayed in the choice of the

8]

material for these purposes, varieties being selected which require
an unnecessary amount of time and care to shape; and which,
after an exposure of a season or two to the atmosphere, assume
a rusty tint, in consequence of containing too large a quantity of
oxide of iron. To avoid the former of these defects, it is only
requisite to examine closely the form and texture of the freshly
fractured surfaces of the rock, which should generally split with
a smooth, even, somewhat conchoidal fracture, and present to
the eye a very regular and close grain, with a clear, uniform,
and decided tint, either of gray, or grayish-blue, or blue. To
detect the presence of an injurious proportion of the oxide of
iron, calculated in course of time to stain the exposed surface of
the rock, one of the readiest and simplest methods is to reduce a
portion to powder, moisten it with a little water, and add a little
pure muriatic acid. The existence of oxide of iron will be
made apparent by a brownish tinge, seen while the material is
dissolving.

(b.) Another highly useful purpose to which this rock is often
applied, is in the construction of McAdam roads. As a road-
stone, to be employed where the intercourse does not require a
very heavy draught, it is at once the cheapest, most readily pro-
cured, and easily broken material accessible to very exten-
sive and important districts, not merely of New Jersey, but of
the Middle States. Much judgment, it is believed, may be dis-
played in the selection of those kinds which wil] prove the toughest
and most difficult to abrade under the wheels. Those possessing
a subcrystalline texture, and a rough, irregular fracture, espe-
cially when they contain a certain amount of silica and oxide of
iron, | have usually conceived to be the best adapted to endure at-
trition. A little practice with the hammer, will soon enable us to
ascertain approximately, the kinds likely to prove most suitable.

(c.) Marbles.—The great calcareous formation which we have
described, is characterized by several varieties which are fairly
entitled to the name of ornamental marbles, when we consider
their fineness of grain and susceptibility of a delicate polish, com-
bined with their several soft and pleasing shades of colour.

Among the beds which pass ordinarily by the name of lime-
stone, we meet with portions uniting the requisites of texture with
the most beautiful and delicate tints; some are of a very pale-

82

blue approaching to white; others are of a dun-colour; while some
are gray and blue marbles, delicately mottled, veined, and shaded.
In the Mendham Valley, a variegated pinkish colour is associated,
in a few cases, with a texture deemed sufficiently fine to admit
of a good polish. The white crystalline marbles of the altered
belts have been already spoken of. The pure white and granu-
lar kind, seen in many places around Franklin and Sparta, and
further to the southwest, would afford, if carefully quarried and
polished, a superior marble; while the clouded kind, such as we
find near Long Pond, might be procured in very beautiful varie-
ties. The presence of the pale-yellow Brucite, in some very white
portions of the granular rock, would constitute a beauty rather
than a defect. Other portions of this altered rock are in some
places delicately arborescent.

A variegated greenish marble, susceptible of an excellent polish,
occurs, connected with small injected veins of serpentine, near
Augusta, adjacent to the anticlinal axis of the Paulinskill Valley.
It has all the characters of an ornamental marble, the rock
being penetrated in all directions by little veins of serpentine of a
lighter and darker green, mingling with the mass of the rock so
as to impart to it numerous beautiful shades. ‘The occurrence of
minute brightly yellow cubical crystals of sulphuret of won in
some parts of the mass, is calculated to heighten rather than
impair its beauty. A change seems to have been induced in the
texture of the rock by the intrusion of the serpentine, nearly
effacing its original marks of stratification, and causing nu-
merous irregular cross joints.

This creates some little difficulty in quarrying it, but if the
excavation were attempted on a larger scale for the purpose of
finding for this marble a regular market, the rock could be pro-
cured in larger and better shaped pieces than at present. It does
not show more liability to irregularities in the quarrying, than
such rocks usually exhibit.

Character of the Lime for Mortar and as a Fertilizing Agent—
The lime from different portions of Formation II. possesses va-
rious degrees of excellence for mortar.

Two principal species include nearly all the varieties of this
rock, however they may differ in point of colour and aspect. The
first of these is composed chiefly of carbonate of lime, the extra-

83

neous ingredients being oxide of iron, sometimes a little oxide of
manganese, a little vegetable or animal organic matter, and water.
The second kind, besides all these several constituents, contains a
large proportion of carbonate of magnesia, from which it derives
peculiar and important properties.

Those beds of the rock which possess, as I have already de-
scribed, a clear decided tint, especially any shade of blue, and a
smooth, sharp, even fracture, and close, fine grain or texture,
will yield almost invariably, a pure white lime, admirably adapted
for making common mortar; but which is destitute of the pro-
perty of hardening under water. Some very dark varieties
furnish a beautifully white and pure lime, the colouring matter
consisting of bituminous substances, which are entirely consumed
in the process of burning. Such limestones are apt to emit a dis-
agreeable foetid smell when broken or strongly rubbed.

The magnesian limestones constitute a very important por-
tion of the formation before us. Until my brother, Professor Wil-
liam B. Rogers, of Virginia, first analyzed these rocks, which he
has done extensively and systematically as they occur in that
State, their existence was hardly recognised, much less their re-
markable abundance. My own researches made in Pennsylva-
nia and New Jersey, confirm the fact of the magnesian character
of a large portion of this great limestone formation.

Their economical value as hydraulic cements, very recently as-.
certained to be dependent upon the presence of the magnesia,
gives additional interest and importance to the developement of
these extensive beds.

No certain guide can be given for recognising the magnesian
varieties of the limestone, as only the eye of an experienced ob-
server will detect those nice shades of aspect, which denote the
presence of both the alkaline earths. The best general criterion,
is a certain dulness in the appearance of the surface, even when
freshly broken, and the absence of that fine smooth grain distinc-
tive of the pure varieties of the limestone.

The recently discovered general fact, already alluded to, that
the property of forming a hydraulic cement depended upon the large
proportion of carbonate of magnesia in the limestone, was first
hinted at by M. Vicat, of France, and since confirmed by an
extensive series of analyses and experiments, carefully conducted

84

by my brother, not only upon specimens of the formation as it
occurs in Virginia, but upon other limestones of New York and
Kentucky, the details of which were submitted to the public in
his annual report on the geological survey of Virginia for the
year 1838. He there demonstrated that the magnesia is inva-
riably a prominent ingredient in all the limes‘which readily set
under water, while the other constituents, s¢/ica, oxide of tron, and
alumina, seem not to be essential, being variable, and most usually
existing in comparatively minute proportions. His researches
thus far made, would indicate that in the specimens yielding an
active hydraulic lime, the average proportion. of the carbonate of
magnesia to the carbonate of lime is about three to five.

In corroboration of these interesting and useful results, I here
present several analyses of the magnesian limestones of New
Jersey. After determining accurately the chemical composition
of each specimen, a portion of the same mass was carefully cal-
cined, made into cement, and left to repose under water, the pro-
gress and extent of the hardening being ascertained by an instru-
ment, devised by a French experimenter for that purpose.

The more highly magnesian varieties proved in every instance
good hydraulic cements.

ANALYSES.
Blue Limestone from Lafayette, Sussex county.
Description. —Colour, bluish gray; texture, close-grained and
subcrystalline.
Specific gravity.— 2838 at a temperature of 56° Fahr.
Composition.—In 100 parts:

Carbonate of lime, - 53:04
Carbonate of magnesia, - 41:04
Alumina and peroxide of iron, 0:96 .
Insoluble matter, = 3°24
Moisture and loss, - 1°72

100:00

Blue Limestone, Johnsonburg, Warren county.

Description——Colour, light bluish gray; texture, slightly sub-
crystalline.

85

Specific gravity.—2'837 at a temperature of 59° Fahr.
Composition.—In 100 parts: ~

Carbonate of lime, - 53°52
Carbonate of magnesia, - 38°74
Alumina and peroxide of iron, 0°73
Insoluble matter, - 6.29
Moisture and loss, 4 0-72

100-00

Blue Limestone, near Anderson, Musconetcong Valley, Warren
County.

Description.—Colour, dark blue; texture, very fine grained and
compact; fracture slightly conchoidal.

Specific gravity.—2-847 at a temperature of 58° Fahr.

Composition.—In 100 parts :

Carbonate of lime, - 53°59
Carbonate of magnesia, - 41-58
Alumina and peroxide of iron, 1-38
Insoluble matter, 3:44
Moisture and loss, 0:01

100-00

This is said to have been employed as a hydraulic cement
with success.

Blue Limestone, south of the Paulinskill, on the road from Newton
to Swartwout’s Pond.
Description.—Colour, light bluish gray; texture, moderately
close grained; aspect, somewhat dull and earthy.
Specific gravity.—2°832 at a temperature of 54° Fahr.
Composition.—In 100 parts :

Carbonate of lime, . 54:95
Carbonate of magnesia, - 33°99
Alumina and peroxide of iron, 2°10
Insoluble matter, - 745
Moisture and loss, - 1-51

100-00

86

Blue Limestone, Hacketstown Valley, Warren county.
Description.—Colour, dull bluish gray; texture, moderately
close grained, and slightly subcrystalline ; has interspersed veins
of calcareous spar.
Specific gravity.—2'831 at a temperature of 69° Fahr.
Composition.—In 100 parts:

Carbonate of lime, - 50:23
Carbonate of magnesia, - 37:13
Alumina and peroxide of iron, 0°63
Insoluble matter, = 9-93
Moisture and loss, - 2-08

100°00

The above five analyses refer, it need hardly be said, to Forma-
tion IL, which will be found, I doubt not, upon an extensive
examination, to be more often magnesian than purely calcareous.

Having shown the carbonate of magnesia to be an abundant
ingredient in many of the limestones, the lime of which is used
among the farmers of those districts for assisting the fertility of
the soil, it may be of some service to the agricultural interests
of the State, to endeavour in this place to correct the generally
prevailing impression, to this day widely propagated by writers,
of the injurious action of magnesian lime upon the land. It is
now clearly established, that a /arge proportion of the lime
employed by the farmers of the southeastern counties of Penn-
sylvania, for a long series of years past, with such eminent
benefit to the permanent fertility of their soils, is, without their
being aware of it, highly magnesian. ‘This is of itself enough to
refute the popular prejudice upon this subject. But the analyses
above given, of a number of those of New Jersey, of well known
repute as to their agricultural fitness, will enable the farmers of
Warren and Sussex counties in particular, to judge of the merits
of this question for themselves, by uniting with the chemical
results here presented, their own agricultural experience. While
the evidence from experiment and trial now brought forward,
goes conclusively to show, that the magnesia cannot be poison-
ous to the crops, agreeably to common belief, it still leaves an
interesting and useful question undetermined, whether the mag-

87

nesia is merely inert, or whether, like the lime, it exerts an ac.
tively fertilizing influence upon the soil.

Nothing short of a series of agricultural experiments, judiciously
planned and perseveringly conducted, aided by chemical analyses
performed upon the limestones used, can settle this important eco-
nomical inquiry. Alive as our farmers are becoming to the ines-
timable utility of calcareous manures, it m' st soon prove to them
a matter of interest, to ascertain whether the magnesia, constitu-
ting often more than 40 per cent. in the lime which they spread,
is really salutary or wholly inoperative.

The white crystalline limestone of the altered belt, especially
of Sussex county, recommends itself strongly for its purity and
whiteness, particularly that procured from the more perfectly
rhombic variety.

It has long been made into lime near Hamburg, from whence
that material has been transported over the Highlands to the towns
of Patterson, Newark, &c., commanding, at times, as high a price
as one dollar per bushel. This is admirably adapted for the finer
kinds of masonry, by the whiteness of the cement which it yields;
and it is especially fitted for making the hard finish for walls and
cornice work.

In the neighbourhood of Lockwood there occurs a fine exposure
of the crystalline limestone, in a belt already described. This
being within about three miles of the Morris canal at Stanhope,
where there is a ready transportation to Newark and other towns
where lime is in demand, the business of burning the stone is
beginning to invite attention. The pure rhombic semitranslucent
variety, which is, toa great extent, free from magnesia, and capa-
ble of producing, when properly burned, a lime of superior excel-
lence and whiteness, is here in great abundance.

The annexed analysis will show the composition, in 100 parts,
of this limestone. Specific gravity, 2.719.

Carbonate of lime, - 95.86
Carbonate of magnesia, - 1.93
Alumina and peroxide of iron, 0.61
Insoluble matter, : 0.07
Moisture and loss, - 1.53

100.00

88

It is a matter of surprise to the traveller, that, along this whole
range, where the sparry limestone is so accessible, and where
wood is comparatively cheap, so very little has been done by the
inhabitants of the region, in manufacturing lime, either for trans-
portation to the ready market of New York, or for home con-
sumption, as a fertilizing agent of inestimable value to the soil.
Over the whole of the Kittatinny Valley and its branches, in New
Jersey, the importance of lime in agriculture has hitherto been
singularly overlooked. Along the Musconetcong and German
valleys, the practice of limeing has of late years become a com-
mon one; but throughout a large part of Sussex and Warren
counties, where the circumstances are especially favourable for its
general introduction, it remains but little attended it. The exam-
ple of the southeastern counties of Pennsylvania should coyvince
the people of New Jersey, that, upon nearly all soils, whether they
lie immediately over the limestone rock itself, or over the slate, or
belong to the sandstone and primary rocks of the hills, or to the
deep loams of the river flats, the application of lime properly
managed leads to sure and permanent benefit.

The magnesian character of some of the white crystalline lime-
stone deserves attention, as it is probable that the rock will pro-
duce a hydraulic cement. Should the question of the compara-
tive inertness or efficiency of magnesia in agriculture be definitely
settled, it may be of importance on this account to know its com-
position.

By analysis, I find that the white irregularly crystalline, or
somewhat granular kind, which abounds near Sparta, and be-
tween that place and Lockwood, and which is so apt to contain
insulated crystals of Brucite, is decidedly magnesian, as the fol-
lowing results will show.

Analysis of the White Granular Limestone of Sparta, Sussex county.

Description—White, opaque, coarsely crystalline, or saccha-
roidal, containing crystals of Brucite and graphite.
Composition.—In 100 parts:
Carbonate of lime, - 82.85
Carbonate of magnesia, - 15.15
Silica, Alumina, Oxide of iron, 2.00

100.00

89

Of the Pond Marl connected with the Limestone, Formation II.

At several places in the limestone districts of the Kittatinny
valley, we meet with a material which is identical with the Lake
Marl of Europe, occurring around the shores and in the beds of
small lakes or ponds, and throughout some of the swampy mea-
dows of Sussex and Warren counties. This useful deposit is only
found where the water is copiously impregnated with the carbon-
ate of lime, and hence it occurs only within, or immediately adja-
cent to, extensive limestone strata. It would seem to owe its
production, in part, to a chemical precipitation from the water;
in part, to the decay of myriads of small testaceous animals, of the
species usually found inhabiting calcareous waters, which, secre-
ting the carbonate of lime to supply the material of their shells,
generation after generation, accumulate it from the water in
great abundance. The ponds where this deposit occurs present
a rather singular aspect, being fringed with a broad white beach.

Analysis of a Fresh Water Marl, from a pond four miles from
JVewton.

Description.—Light ash colour ; pulverulent.
Composition.—In 100 parts:

Carbonate of lime, - : 90:22
Carbonate of magnesia, « 1:91
Alumina and peroxide of iron, - 0°61
Insoluble matter, - Z 3:13

Organic matter, moisture, and loss, 4:18

100-00

In consequence of the peculiar appearance derived from this
deposit, two or three of the ponds containing it are called on the
map White Ponds; for instance, two ponds west of Pimple Hill,
in Sussex; the more northern one being, however, incorrectly
so termed, as the marl is confined to the other. There is also
another pond about one mile north of Marksboro’, in Warren.
These, however, are not the only depositories of this useful sub-
stance: I enumerate the following as its localities already ascer-
tained: White Pond, near Pimple Hill; a pond near Brighton;
Stickles Pond, two miles south of Newton; a pond a mile and a

g*

90

half northwest of Andover; the White Pond near Marksboro’; a
pond at Stillwater; and some of the small ponds and marshy
grounds in the neighbourhood of Hope.

The marl likewise occurs in a marshy meadow to the northeast
of La Fayette, and again near Peter Merkel’s, in the same range.
Considering the well-tried value of this material in Europe, its im-
portance to the agriculture of the districts which possess it, and
its abundance in the two upper counties of the State, it seems truly
strange that its application to the adjoining soils, should hitherto
have been almost entirely overlooked by the farmers.

A material so easy of access, demanding no preparation to
suit it for the soil, and unquestionably so efficient when judiciously
applied, ought to be extensively used. ‘Though much neglected
until recently, this useful substance is beginning to attract atten-
tion to its valuable properties as a manure. Ample evidence is
furnished of its fertilizing agency, by experience in Sussex county,
even if we had not the testimony of many districts of Europe in
its favour. It should be taken from the pond or low grounds
where it abounds, and drawn to some convenient place, to remain
in heaps, exposed to the air for several months. By this exposure
it becomes dry and pulverulent, and is made to mingle with the
soil more uniformly than when in its recent wet condition.

Brown or Hematitic Iron Ore.—Next to the limestone itself, the
most useful mineral which belongs to this formation in New Jer-
sey, is the brown, or hematitic iron ore. Though much less exten-
sively diffused than in other parts of the same great valley, further
to the southwest, this ore, from its excellent properties, is to be
regarded as a valuable addition, recently discovered, to the
mineral resources of the State.

The main deposit, moreover, is interesting, both in an economi-
cal and scientific light, on account of its great extent, and the
singular geological circumstances under which it occurs.

As already mentioned, when describing the ranges of the altered
white limestone, this large accumulation of the ore occupies the
summit and slopes of a narrow ridge of the sparry rock extend-
ing parallel with the Pochuck Mountain, at a small distance from
its base. The situation of the mine is about two and a half miles
northeast of Hamburg, chiefly upon the western declivity: of the
hill. Very little rock is visible in the immediate vicinity of the

91

ore, which exists in the concretionary state, imbedded in a highly
ferruginous clayey loam, which displays the utmost variety of
colour, texture, and compositicn, being mottled and streaked
with clays of all shades, white, yellow, red, and brown. The ore
distributed irregularly throughout this mass, presents no less
diversity of aspect, though it all belongs to one species, denomi-
nated brown tron ore. It occurs massive and cellular and some-
times fibrous, also in a mamillary and botryoidal form, and is often
so hard and compact as to require blasting. The workings are
generally dry. The earth in some portions of the mine gives evi-
dence of resulting from decayed felspar and the other consti-
tuents of the adjacent gneiss rock, and contains beside much
plumbago in a disintegrated and pulverulent state, clearly indi-
cating that the dissolution of the crystalline limestone has been,
in part at least, the cause of this large accumulation of ore.

The mineral is of excellent quality, yielding a much superior
iron to that procured from the magnetic ores of the adjoining pri-
mary districts. The facility with which it may be smelted in
blast furnaces, compared with the magnetic ore, is another great
recommendation, and when we consider that the latter, by the
usual process of reduction in bloomery forges, requires from six
hundred to eight hundred bushels of charcoal to produce a ton of
malleable iron, while this ore may be brought into the condition
of cast iron by an expenditure of not more than two hundred
bushels, costing between five and six dollars per hundred bushels,
we are still further impressed with its value.

Though but five or six years in use, this ore has already become
rather extensively worked, being not only smelted at a large fur-
nace recently erected near Hamburg, but hauled over the Wall-
kill Mountain a distance of twelve miles to Clinton Furnace, and
a still greater distance to Ryerson’s Furnace, near Pompton.

Another mine of similar brown iron ore, discovered rather be-
fore that in the ridge near Pochuck, lies about a mile and three
quarters east of Hamburg, above the junction of two small streams
called Sand Pond and Mud Pond creeks. This deposit, already
alluded to, is embraced between the primary rocks of the base of
the Wallkill Mountain and a small knob of gneiss a little west of
it, and lies only a short distance from the northern termination of a
belt of white crystalline limestone, the disintegration of a portion

92

of which, once occupying this little valley, may have possibly
been the source of the ore.

The present excavation is only about 140 feet long, 40 wide,
and 40 deep. This deposit of ore was first brought to light, a few
years since, in sinking a well.

Owing to the occurrence of much diluvial matter over the sur-
face of the narrow valleys which embrace the altered limestone,
it is highly probable that considerable bodies of the ore exist
where few or no indications at the surface betray its presence.
The prevalence of the mineral near the white limestone, under
circumstances that imply it to have come from a rather exten-
sive dissolution of that rock, holds out a prospect of finding it in
other localities besides the above. ‘The explorer should carefully
note the signs of the removal of the altered limestone, by denuda-
tion or solution, in spots where the products of its destruction
would, from the features of the ground, be most likely to remain
in their usual form of a deep loamy ferruginous deposit. Such
places will be the broken slopes of hills and the basins in the cen-
tre of confined valleys.

Hematitic brown iron ore occurs occasionally, though not in
extensive deposits, in the limestone valleys between Schooley’s
and Scott’s Mountains. It has been found, for example, though |
in rather humble quantities, very pure, between Mansfield and An-
derson villages, not far from the Morris canal. It exists likewise
in more abundance in connexion with the belt of limestone which
forms the valley of the Delaware river, between Belvidere and
Easton, having been excavated to some extent in the vicinity of
Foul Rift. Much of the ore in this neighbourhood belongs to the
highly valuable stalactitic variety usually denominated pipe ore.

Respecting the geological position of the brown or hematitic
iron ore, we may give it as a general rule, admitting of no
exception in New Jersey, that it abounds only in the highly
ferruginous soils, which either immediately cover this limestone
formation, or which lie closely adjacent to it. In Pennsylvania
and some of the other States such are not its invariable rela-
tions, as several of the other rocks of the older secondary series
present us with extensive deposits of the same species of ore.

Sulphate of Barytes.—West of Newton about two and a half
miles, there occurs a narrow vein of the sulphate of barytes,

93

_ the dimensions of which, where it has been explored, appear to
be too inconsiderable to render it an objeet of profit. It is
crystalline and of a pretty pure opaque white, and has been met
with in two separate spots contiguous to each other. The
locality is near the disturbed anticlinal axis of the narrow belt of
blue limestone, immediately northwest of the main range of slate
next northwest of Newton, being removed from the principal
Paulinskill tract of limestone by a narrow intermediate synclinal
zone of slate.

Upon the site of one of the excavations made some years
since for this mineral, a very absurd mining project was under-
taken, not to procure the sulphate of barytes, which, if abundant,
might repay the miner, but in the futile hope of revealing a mine
of silver. Every informed geologist or scientific miner would
pronounce at once, from all the mineral indications here present,
and from the nature of this and the other rocks, that such attempts
at mining for the precious metals in these strata are likely to
prove wholly abortive; nevertheless a shaft sixty feet deep and
at a cost of two thousand dollars has already been dug. I deem
it my duty to state, that I could discover in this mine nothing that
seemed to contain a trace of silver, or any thing to justify the
anticipation of finding it.

The barytic mineral has become of recent years a substance
of considerable demand in commerce, from the rather extensive
use now made of it by the manufacturers of white lead, many of
whom have been driven by the spirit of competition to mingle it
in a finely levigated condition, in a greater or less proportion,
with their manufactured article. This adulteration, if such it can
be called, would seem not to affect materially the interests of the
consumer, as the mineral appears rather to dilute than injure
seriously the quality of the white lead, while the reduction in the
price will compensate, or nearly so, for the somewhat increased
quantity of the paint which it becomes necessary to employ.

SECTION II.
Of the Slate of the Kittatinny Valley, Formation III.

Geographical Range of the Formation—Having adopted the
ascending order in this description of the rocks of the ancient

94

Secondary or Appalachian System, the next stratum which pre-
sents itself, reposing immediately on the limestone, is the slate of
the Kittatinny Valley. This rock, as already intimated when
tracing the axes of elevation in the limestone, ranges in several
long and narrow belts, the limits of which were specified while
treating of their position in the synclinal troughs embraced be-
tween the upheaved zones of the limestone. Extending our pre-
sent enumeration to all the several belts within the State, we
have now to include, with those alluded to, the principal tract of
the region which occupies the northwestern side of the Kittatinny
Valley, throughout its whole length across New Jersey.

Tracing the limits of these different ranges with as much
minuteness as the purposes of a general description render neces-
sary, we shall begin, as usual, with those which lie farthest
towards the southeast.

The first is that narrow belt at the Wallkill, about three miles
northeast of Deckertown, which runs southwestward, passing
about a mile northwest of Hamburg, and a little southeast of Har-
monyvale and Lafayette. It terminates about two miles south-
east of Newton in a narrow point. This low ridge of the slate is
in many places not more than a fourth of a mile in width, while
its length is about fourteen miles. It owes its position and form to
its occupying the long synclinal axis included between the anti-
clinal axes of Pochuck and of Harmonyvale. Its beds dip
from each margin at a gentle angle towards the centre of the
tract.

Proceeding to the southwest, we meet two other narrow bands
of slate, nearly in the prolongation of that already mentioned.
One of these commences a little east of Reading’s Pond, and
extends, passing directly west of Greenville, almost to Sink Pond.
The other lies in a parallel position at a short distance to the
northwest, the two being separated by a narrow valley of the
limestone, where that formation has been elevated along an anti-
clinal axis. Each of these little belts of slate takes the form of a
low synclinal ridge.

Another somewhat larger belt, of nearly similar breadth, com-
mences at Johnsonburg, and ranges past Hope, where it deflects
a little, extending to the village of Beaver Brook, near which it

95

terminates. Like the other corresponding tracts, it has the form
of a low narrow ridge, bounded on each side by limestone,
which dips beneath it, placing it in the middle of a synclinal
trough.

The next tract of slate, though in the general synclinal arrange-
ment of its strata resembling the others, is one of far greater
extent. Both its southeast and northwest margins have been
already defined, when tracing the borders of the limestone, but
for the sake of connexion we may briefly recapitulate them here.
Beginning at the Wallkill, near the New York State line, the
southeast boundary of this tract of slate runs to the southwest,
passing near Deckertown, and northwest of Harmonyvale, New-
ton, and Johnsburg. Here it deviates more towards the west,
until it passes the Free Church between Centreville and Hope.
There it deflects to the south, passing Beaver Brook, and running
thence in a southwest course, reaching the Delaware a little above
Belvidere. ‘The northwestern boundary, beginning on the Dela-
ware near the mouth of the Paulinskill, pursues the southern side
of that stream to Gravel Hill, near which it crosses it; recross-
ing a little east of White Pond, it thence extends in a northeast
direction for several miles to a point about three miles north of
Newton. Here it unites with the southeast margin of a narrow
belt of the formation which follows the course of the Paulinskill
for several miles. Beyond, where this smaller tract joins the
principal one, the boundary which we are tracing proceeds to
the northeast, again passing to the southeast of Augusta, and
terminating near Coursenville, where the whole zone of slate
southeast of the Paulinskill merges in the still more extensive one
which follows the base of the Blue Mountain.

The southeast edge of this northwesternmost tract, beginning
at the Delaware, about three-fourths of a mile above Columbia,
pursues the northwest side of the valley of that stream to Coursen-
ville, passing north of the little village of Walnut Valley, and
northwest of Swartwout’s Pond. Uniting with the former wide
belt at Coursenville, the two tracts beyond that point have for
their southeastern limit the boundary already traced, which
passes near Harmonyvale and Deckertown to the Wallkill.

The base, or rather the southeastern flank of the Blue Moun-
tain, constitutes the general northwestern boundary of the whole

96

slate formation of the valley. Near the Delaware, the common
limit of the slate and the overlying sandstone of the mountain is
seen at a moderate elevation above its base; but in Sussex,
between Culver’s Gap and the State line, the slate rises upon the
eastern slope of the ridge almost to its summit, giving a fertile
soil to the side of the mountain, and presenting, in a long line of
cultivated farms, a landscape full of pleasing and picturesque
beauty.

Composition and structure of the rock.—The ordinary character
of the third formation of the Appalachian system, as it prevails
in New Jersey, is that of a dark blue argillaceous slate; it is,
however, very various, both as respects its colour and com-
position. It occurs in belts of almost every hue, black, blue,
dark gray, bluish gray, dingy olive, dull brown, and even some-
times yellow.

It exhibits every grade of relative fineness and coarseness of
texture, from that of the finest grained roofing slate, to that of a
rough argillaceous sandstone.

At its junction with the subjacent limestone, its beds are often
almost black, and more or less calcareous, while the contiguous
upper layers of that rock partake in some degree of the argil-
laceous composition and structure of the slate. Near its upper
limit, in like manner, where it and the gray sandstone of the
mountain are in contact, it acquires a somewhat arenaceous
texture, and in certain layers passes to a gray argillaceous sand-
stone.

Nearly all parts of this extensive formation, which is evidently
of very great thickness, present that highly curious feature of
structure denominated cleavage. This remarkable tendency of
the mass to split into thin plates by planes of cleavage, which
preserve a uniform direction and inclination over extensive tracts,
independently of all variations in the texture of the rock, and of
all changes in its dip, is a feature which belongs to many of the
ancient slate rocks, both of the old and new continents; but.in
few regions can it be studied on a more extensive scale than in
the Kittatinny Valley, where it is visible for a great distance on
both sides of the Delaware river. While the beds of slate through-
out a large portion of the northwestern belt dip towards the base
of the Blue Mountains, or to the northwest, and while those of the

97

next great zone to the southeast, especially near the Delaware,
have been disturbed by an anticlinal axis giving them both a
northwestern and southeastern dip, the planes of cleavage are
observed to maintain invariably a southeastern, or, more properly,
a southern inclination, which is usually between 40° and 60° to
the horizon. ‘Their strike, or the line formed by their intersection
with a horizontal plane, is, therefore, far from coinciding with
the prevailing strike of the strata themselves. And it is nota
little curious, that this law, of a nearly south-southeast direction
in the dip of the cleavage surfaces, holds true, not only of the
slate but of all the contiguous formations of the series, except the
coarse sandstone and conglomerate rocks of the mountain, affecting
the softer variegated shales, beds of limestone, and olive-coloured
slates of the still higher rocks, which occupy a breadth of many
miles to the northwest. But its vast extent is more particularly
seen, when we trace the formations in their longitudinal course
along the Kittatinny Valley, where we may behold the cleavage
planes preserving their southeastern dip, with scarcely an inter-
ruption the whole distance, from the Hudson to the Potomac, and
indeed to far more distant limits in both directions.

The theoretical discussion of the interesting problem, the cause
of this truly curious general fact, would be out of place in a
work like the present, restricted, as it is, to the description of a
comparatively small tract of the extensive region over which
this phenomenon prevails. But a hope is cherished, of my being
able at some future day, to connect it with views concerning the
elevation of our primary chain and the neighbouring axes, sus-
tained by facts, and a train of reasoning which may afford,
perhaps, a satisfactory solution of this apparently obscure enigma.

The occurrence of workable roofing slates, is connected with
the presence of these cleavage planes. Hitherto they have been
discovered only in the belt which ranges near the base of the Blue
Mountain, having never been found of sufficient purity but in the
vicinity of the Delaware river, near the Water Gap.

The largest quarry is on the west side of the river, in Penn-
sylvania ; a smaller one, yielding both roofing and writing slates of
excellent quality, lies nearly opposite, on the eastern side of the
river, in New Jersey. In both of these quarries, the true dip of
the rock is towards the west-northwest, at an angle of about 30°

9

98

This is detected by the inclination of the numerous thin layers or
ribbons, of a different colour from the rest of the rock, marking
the sedimentary structure and the true planes of deposition. The
dip of the planes denoting the cleavage is towards the south-south-
east, at an average angle of 50°, except where it is affected
in the Pennsylvania quarry by a small fault, which, traversing
a part of the slate, not only causes a local deviation in the dip of
the stratum, but an alteration in that of the cleavage also.

Several favourable circumstances of structure and position,
must combine to adapt any portion of the formation to being
quarried for roofing slate with success.

The rock must be of a fine uniform and compact grain, as
free as possible from all crushes or contortions of the stratum,
cJeaving with facility into thin plates in one direction, and
breaking with difficulty in every other. It should be exempt,
moreover, from su/phuret of tron, which is often found finely
disseminated in the coloured seams or ribbons, and which upon
exposure to moisture, soon causes a rapid disintegration of that
portion of the mass. The quarry should be situated, if possible,
where a small rivulet of water may be conducted over the rock,
to preserve it in a moist state, in order to render it more easily
and evenly cleaved.

In splitting and trimming the slates, care is taken to reject the
coloured ribbons, lest, in course of time, they should undergo
decomposition.

It is somewhat curious, that while the belt of pure slate
between any two of these ribbons is almost perfectly uniform in
texture and quality, there often prevails a sensible difference in the
respects between two adjacent belts, though only separated by a
ribbon of a slightly different colour, less than an inch in thickness.
It merely marks a difference in the composition of the sediment,
before and after that which formed the more heterogeneous
ribbons.

Inferring from the highly cleavable condition and firm grain
of much of the slate of the belt at the foot of the Blue Mountain,
for many miles east of the Delaware, it would seem not im-
probable, that a minute examination of the stratum for roof-
ing slate, might be rewarded with success at more points than
one.

99

Except the highly useful article just alluded to, the formation
described would appear not to present us with materials of much
interest, as respects their economical applications.

Of iron ores, this formation has been found to exhibit very few
indications in New Jersey, while of other minerals either useful
or curious, it would seem to be equally destitute.

Some of its less argillaceous sandstone beds appear adapted
to the ordinary purposes of a building stone, but care is requisite
in the selection, as too large a share of argillaceous matter leads
to a dissolution of the rock by the frost.

The soil over this formation is usually rather meagre and of
inferior fertility, yet it is susceptible of remarkable amelioration
from the application of lime, which throughout the whole length
of the Kittatinny Valley, may be procured at a distance rarely
exceeding four or five miles from the remotest parts of the slate
districts.

Gray Sandstone of the Kittatinny Mountain, Formation LV.

Geographical Range of the Formation.—Resting immediately
upon the great slate stratum above described, with a conformable
northwestern dip, there is a thick series of hard and massive
gray sandstones, occasionally having the coarseness of a quartzose
conglomerate. These rocks are confined to the long, narrow, and
nearly straight mountain ridge, remarkable for its steep flanks
and almost perfectly level summit, called the Kittatinny or Blue
Mountain, which crosses the counties of Warren and Sussex from
the Delaware Water Gap. to near Carpenter’s Point, but which,
in the form of a nearly continuous mountain, reaches from within
a few miles of the Hudson, near Kingston, to Cumberland county,
in Pennsylvania.

Unlike the somewhat gradual transition witnessed between the
slate and its subjacent limestone, the passage from the slate, which
occupies the lower half of the eastern slope of the mountain, to
this overlying sandstone, is abrupt and every where well marked.
Cropping out in many places in a bold and rugged escarpment
along the upper part of the southeastern side, it forms the rough
but level summit of the ridge, and usually about one half of its
northwestern slope.

The relative position of this gray sandstone to the overlying

100

red sandstone and shale formation of the northwestern flank, and
to the underlying slate, and the conformable dip of all these rocks
towards the northwest, is well exhibited in that fine natural gorge
of the mountain, the Water Gap of the Delaware. Here, the en-
tire structure of the ridge is exposed, showing the gray sandstone
rising in bold grandeur from the water’s edge to the crest of the
mountain, an elevation of about fourteen hundred and fifty feet.
The ridge preserves this height with a remarkably straight and
even summit for many miles, in both directions from the river.
This levelness and perfect straightness of the mountain top, the
regularity of its grand escarpment on the east, and the striking
uniformity in the general dip of its strata, suggests the remarkable
equality in the intensity and direction of that force from below,
which uplifted from their deep bed under the waves, this pon-
derous mass of rocks.

Composition and Structure-—The gray sandstone formation of
the Kittatinny Mountain consists of a thick series of hard white
and whitish-gray siliceous rocks of various degrees of coarseness,
from that of a fine-grained pure sandstone to that of a quartzose
conglomerate of thickly set pebbles, averaging half an inch in
diameter; these several varieties are found interposed in frequent
alternations, though the fine-grained sandstones most abound in
the upper half of the stratum, while the conglomerates prevail
to rather greater amount in the lower division. In the vicinity of
the Lehigh river, in Pennsylvania, the main deposit consists of
pebbles, often of great size, which compose the lowest beds of
the formation, resting in immediate contact with the subjacent
slate.

From the Susquehanna river to the district of the Lehigh and
Delaware, the formation would appear to augment progressively
in thickness and general coarseness of composition, being only
about four hundred feet thick near the first river, and almost two
thousand feet at the Lehigh; but advancing from the Water Gap
of the Delaware towards the Hudson, it again abates somewhat
in thickness, retaining, however, its full proportion of the white
quartzose conglomerates.

Upon examining the composition of the rock, it will be found
to consist of rounded fragments in the condition of sand and fine
gravel, derived from the primary rocks lying southeast and east

101

of it, and in part from the three inferior older secondary forma-
tions of its own group, ranging parallel with it in the Kittatinny
Valley. Among these materials we occasionally meet rounded
pebbles of the flint or chert, characteristic of the limestone, though
none of the softer carbonate of lime itself; also small flattish frag-
ments of the directly underlying slate rocks.

These constituents, of themselves, imply that some great dis-
turbance of the shores of the Appalachian sea must have taken
place suddenly, interrupting the deposition of the slate, and giving
rise to a series of new and more violent currents, sweeping into
it a coarser class of materials from the neighbouring land and
from the freshly risen sediments which now form the Kittatinny
Valley. But on this interesting point we are not left to inferences
derived merely from the nature of the rock ; for towards its north-
eastern termination, we find this formation, as we approach the
Hudson, resting unconformably, with a gentle dip to the north-
west, upon the upturned and contorted beds of the slate, giving
unequivocal proof of the violence of the subterranean actions
which attended the commencement of this extensive sandstone
deposit. Whether the lower formations of the Kittatinny Valley
emerged entirely above the waves at this epoch, in the tract which
they now occupy in New Jersey, is a point open to doubt, though
there exists strong evidence for believing, that, over some portions
of their range at least, further to the northeast, in the neighbour-
hood of the Hudson and beyond it, they were thus uplifted. The
general augmentation in the coarseness of the materials of the
sandstone formation, as we advance from the Susquehanna towards
the Hudson, would tend to confirm the opinion, that in this latter
quarter the disturbances which ushered in this fourth epoch of
the ancient secondary period had their greatest energy.

The gray sandstone of the Kittatinny Mountain is the only
rock of the whole lower secondary group within the State,
from the limestone of the eastern side of the valley to the lime-
stone of the olive slate formation skirting the Delaware in Sussex
county, which exhibits none of the oblique cleavage planes so
conspicuous in Formation ILI. Its massive beds are traversed by
joints, having the same dip and strike, and attributable, probably,
to the same origin.

Its quartzose materials and coarse aggregation have probably

g*

102

interfered with its assuming this structure on a minuter scale.
It may be given, indeed, as an almost universal rule, applicable _
to the whole range of the Appalachian rocks, that wherever this”
cleavage peavails: extensively, it shows itself in the sandstones on
a scale commensurate, as to distance between the planes, with the
thickness of their beds and their coarse arenaceous character.
For even in these coarser strata, though the divisional surfaces are
three feet and more asunder, they preserve their regularity and
constancy of direction, and their parallelism to the slaty cleavage
of the argillaceous parts of the series.

ORGANIC REMAINS.

The relics of organic life imbedded in this great sandstone
formation are singularly few, if we except two or three interesting
species of marine vegetation. 'These belong to the tribe of
extinct seaweeds called fucoides. The principal varieties are
the fucoides Brongniartii, and the fucoides Alleghaniensis. The
cliffs in the middle of the gorge of the Delaware Water Gap
exhibit fine specimens of the former, covering with a beautiful
reticulation the faces of the white sandstone beds over many
square yards of surface. The latter species abounds where the
formation alternates in its upper layers with the lower beds of
the overlying red sandstone. Properly considered, it is a fossil
more strictly characteristic of the latter rock, being confined in
this alternation of the formations chiefly to the red layers.
Hitherto I have discovered but one fossil of the animal kingdom
in the rock of the Kittatinny Mountain.

This is a small species of terebratula of a nearly spheroidal
form, found as yet in few places, and chiefly in the uppermost
beds of fine-grained white sandstone. The turbulent condition of
the currents in the earlier periods of the general deposit, would
seem to have interfered with the multiplication of animated races
on the sandy bed of that ancient unquiet sea.

ECONOMICAL GEOLOGY.

The white and light gray sandstones of this formation seem,
from their durability and the regularity of their stratification, to

103

be well adapted to some of the purposes of a building stone,
though their great hardness, and the difficulty in shaping these
rocks, must restrict their usefulness chiefly to those objects where
very massive or rough structures possessing great strength are
intended.

The white quartzose conglomerate of this range in New York,
is used for making mill-stones, which consist each of a single
block. ‘They are principally made at Esopus, the rock being
taken from that part of the Kittatinny called the Shawunkunk
Mountain, where the quartzose conglomerate is in great perfec-
tion. It is reputed to be well adapted for the purpose. As strata
of the very same aspect and composition occur abundantly on
the northwestern flank of the mountain in various portions of its
range through Sussex, little doubt can be entertained that were
the means of transportation as convenient as at Esopus, this
application of the conglomerate would claim attention in New
Jersey.

Throughout this State the formation before us is singularly
destitute of useful ores or minerals. In a high valley, a little
northeast of the Delaware Water Gap, between the two ridges
which here form the general summit of the mountain, a small
body of very excellent hzmatitic iron ore has been found, not
showing, however, any indications of an abundance.

Red Sandstone and Shale of the northwestern base of the Kittatinny
Mountain, Formation V.

Geographical Range—Immediately overlying the formation
just described, and occupying the valley at the northwestern
base of the same mountain, upon the flank of which it sometimes
rises to a considerable elevation, occurs a thick and somewhat
varied formation, consisting of red and variegated sandstones
and shales.

The general range of these rocks is, of course, in a belt
parallel with the mountain, from the Delaware Water Gap to
Carpenter’s Point, where they enter the State of New York.
Between the Water Gap and Wallpack Bend they occupy the
narrow zone which separates the base of the mountain from the
river; but, northeast of the Bend, they follow in a rather wider

104

tract the valley of the Flatkill, cut off from the river by a parallel
belt cf fossiliferous limestone, the lower member of Forma-
tion VIII.

These red sandstone rocks appear not to reach the Hudson;
but, in the opposite direction, they extend a vast distance to the
southwest, where they are largely developed, as they likewise are
along the southern side of Lake Ontario.

Composition and Structure-—The features of this formation are
considerably less diversified where it ranges across New Jersey
than where it rises to the surface in some of the other States.
The particular belt which follows the base of the Kittatinny
Mountain is marked, indeed, throughout its whole course, by
very little variety in the composition and appearance of the rock.
Its more variegated aspect is confined to the belts which lie
at a considerable distance to the northwest. As it occurs in
New Jersey, this rock consists, in its lower beds, of a dark-red
sandstone of a very ferruginous composition and extreme hard-
ness; and in the middle and upper divisions of the stratum, of a
brownish-red shale, and a very argillaceous sandstone, which are
sometimes slightly calcareous. These latter layers are occasion-
ally divided by thin bands of a different colour, commonly
greenish or yellow, but of the same composition; which, as the
whole rock is much affected by cleavage, assist materially in the
determination of its dip. Throughout its entire range the forma-
tion exhibits the peculiar structure resulting from cleavage;
this is particularly well developed in the neighbourhood of the
Delaware Water Gap; where it offers some interesting pheno-
mena to the geological student. An anticlinal axis of considerable
magnitude traverses the formation for several miles, ranging
immediately northwest of the Water Gap, disturbing the rocks
from their usual northwest dip, and giving to them a series of
undulations, distinctly traceable by aid of the lighter-coloured
bands above mentioned. Notwithstanding these irregularities,
the direction of the dip and strike of the cleavage surfaces con-
tinues every where the same, only slightly modified in their incli-
nation to the horizon, where the cleavage and true stratification
nearly coincide, in which case the latter exerts some influence.
The usual dip of the cleavage is to a point between south-south-
east and south, conforming entirely in angle and direction to

105

that witnessed in the argillaceous rock on the other side of the
mountain.

The only organic remains hitherto met with in the belt of
red sandstone and shale which traverses New Jersey, are the
marine vegetable relics already spoken of; the species denomi-
nated fucoides Alleghaniensis being by far the most usually
found.

ECONOMICAL GEOLOGY.

The argillaceous composition of this rock, and the extent to
which it is affected by cleavage joints, unfit it, to a great extent,
for usefulness as a building stone. In other parts of its wide
range, at a distance from the Kittatinny Mountain, the for-
mation includes a highly valuable seam or bed of fossiliferous
iron ore, which is becoming well known throughout the central
counties of Pennsylvania and Virginia; but this valuable mineral
is wholly wanting where the rock rises to the surface to form
its most southeastern belt at the base of the Kittatinny, and this is
the portion of it which alone crosses the State of New Jersey.

In that part of the formation which ranges between the Water
Gap and Wallpack Bend, two or three spots occur where copper
ore may be seen in small amount; but all hope of discovering in
this region a valuable vein of this mineral, must prove, I conceive,
entirely illusory. At an early period in the settlement of the dis-
trict, two or three excavations were undertaken in search of the
ore, at the western base of the Blue Mountain, near Paha quarry,
but nothing was reached of sufficient value to reimburse the ad-
venturers. The mining holes are now obstructed by rubbish, but
the specimens of the ore indicate nothing to warrant a renewal
of the attempt.

A few indications of copper ore, chiefly the green carbonate,
amounting in reality to little more than stains upon the rock,
occur in the gorge of the Water Gap, connected apparently
with the lower portions of Formation V. Nothing in the geology
of the Blue Mountain or its neighbouring rocks, so far as the
portion of it lying within New Jersey has been investigated, sug-
gests the occurrence of metalliferous veins of any magnitude; in-
deed, the structure of the whole region is adverse to the supposi-
tion, though various legends of the ores of silver and lead having

106

been discovered here, are yet current among those ignorant of
the subject.

Fossiliferous Limestone of the Delaware, Formation VIII.

Geographical Range.—Resting conformably above the forma-
tion last described, there occurs an interesting and important
rock, the uppermost of the older secondary strata embraced
within the limits of the State. It is a blue fossiliferous limestone,
occupying, if we adhere to a simple classification of the strata, a
position near the bottom of the eighth formation of the series. Its
dip is invariably towards the west-northwest, at an angle averag-
ing about 30°.

This rock enters the State at Carpenter’s Point, whence it ex-
tends in the form of a rather steep ridge, parallel with the general
course of the Delaware to the Wallpack Bend, where it crosses
the river into Pennsylvania. This ridge has the valley of the
Flatkill at its southeastern base, for nearly its whole length,
bounding which, it forms in many places a rather steep escarp-
ment. Between its northwestern base and the river, there usually
extends a narrow diluvial plain, in one or more low terraces,
forming the beautiful and fertile flats of the Delaware.

The Boer appears to increase in thickness as we trace it north-
eastward from the Wallpack Bend. In fact it only begins to de-
velope itself as a separate member in the series of our strata, be-
tween the Wind Gap and the Delaware Water Gap in Pennsylvania,
This expansion, conjoined with a gradual reduction in the angle
of its dip as we advance towards Carpenter’s Point, causes the
stratum to occupy, in the vicinity of Milford, a considerable
breadth. This is the same rock which forms the chain of the
Helderberg hills, west of Albany, in New York.

Composition and Structure.—The prevailing aspect of this rock
is that of a rather pure blue limestone, embracing the two leading
varieties, that consisting of the carbonate of lime alone, and that
in which the carbonate of magnesia also forms an important
part. It has usually a fine close grain, a smooth fracture, and a
clear bluish or bluish-gray colour; other portions of it, however,
depart from these characters, being sometimes of an argillaceous
and earthy texture, sometimes sparry or subcrystalline, and some-

107

times so replete in fossil, shells, and zoophytes, as to possess no
distinctive uniform grain.

The following analysis will serve to show the composition of
this rock, as found at the Wallpack Bend.

Specific gravity.— 26-94

Composition. In 100 parts:

Carbonate of lime, - 89.52
Carbonate of magnesia, - 1.45
Alumina and peroxide of iron, 1.03
Insoluble matter, = - - 7.00
Moisture and loss, - - 1.00

100.00

Though it is not difficult, by close attention, to discern its
planes of stratification, and thence to recognise its dip, yet, like
all the calcareous and argillaceous strata within the State, it is
extensively pervaded by the system of cleavage planes, already
menticned as traversing the rocks below it in the series. These
sometimes so efface all traces of the dip, as to compel the ob-
server to resort toa careful scrutiny of the position assumed by the
shells and other flattish bodies, whose larger diameters will com-
monly be found in the plane of the stratification. The average
inclination to the horizon of the cleavage planes is about 50°, their
direction being to the south-southeast, or south.

An attention to these features of structure and stratification
will prove important in all cases where quarries are to be opened
in this formation.

Organic remains.—It not being consistent with the plan of the
present work to offer a series of engravings of the several fos-
siliferous formations of the State, I must content myself with in-
dulging the hope of doing justice to this interesting subject through
the medium of a different publication.

Superficial Deposits——A somewhat curious deposit of coarse
heterogeneous diluvium, cemented into a true conglomerate by
the infiltration of carbonate of lime, occurs in a bed of some ex-
tent, on the western side of the Flatkill, not far above its mouth,
resting immediately under the escarpment of the limestone. The
calcareous matter has acted so as to agglutinate the coarse

108

gravel swept to this point from the valley of the Flatkill and from
the flank of the adjacent mountain.

The obvious identity as to mode of origin between many rocky
conglomerates of the secondary periods, and masses such as this
of relatively modern date, in which we behold unequivocal evi-
dence of the short duration and violence of the action by which
the miscellaneous debris from the adjacent rocks was hurled to-
gether, will aid us, when adverted to again, to understand the
nature of the circumstances that gave rise to the patches of cal-
careous conglomerate which form the uppermost deposit of the
middle secondary strata, immediately at the southeastern base of
the Highlands.

ECONOMICAL GEOLOGY.

The purer varieties of the limestone of this formation pro-
duce, by burning, a lime in no respect inferior to that derived
from Formation II., either for building purposes or for agri-
culture. The numerous beds of magnesian limestone furnish a
source for hydraulic cement, which may, at any future day,
where circumstances shall warrant it, be manufactured along
the Delaware at a very small expense. It is this same rock, in
its range to the northeast, which has for some years past, at Ron-
dout, near the Hudson, yielded a superior cement at a low price,
and in large amount.

Travertine occurs in two or three localities in Sussex, at the
base cf the ridge formed of this limestone stratum. The water
percolating through the rock, carrying with it only the carbonate
of lime and leaving undissolved the oxide of iron, silica, and
other impurities of the stratum, must of course, in depositing its
calcareous particles, produce a material of great purity. This
deposit, called travertine, is usually in the condition of a yellowish,
porous, concretionary limestone, which burns into lime with great
facility, and yields a product of extreme purity and whiteness. It
usually collects near the base of limestone rocks, where copious
springs, highly charged with the calcareous matter of the stra-
tum, enter moist meadows or swampy grounds. It is of two
kinds, concretionary or stony, and pulverulent. The first is well
adapted for making into lime, or, when procurable in sufficiently

109

large blocks, forms a good building stone. The latter kind is often
beneficially applied to the soil, being identical, in i with the
pond or swamp mari already spoken of.

The travertin, or calcareous tufa, which is ene name it
bears, exists in both these varieties, on the Little Flatkill, about
two miles southeast of Dingman’s Ferry, being deposited a few
hundred yards from the base of the Limestone Hill by a small
rivulet. A similar collection of this material occurs nearer to
the river side, a little above the ferry; and traces of its existence,
though in rather small deposits, are not unfrequently noticed
along both bases of the ridge for a distance of several miles.

Subjoined is an analysis of the travertin deposit, as found near
Dingman’s Ferry.
Composition.—In 100 parts:

Carbonate of lime, - - - 93:53
Carbonate of magnesia, = - O15
Alumina and peroxide of iron, - 0-42
Insoluble matter, - - - - 4:24

4 Organic matter, moisture, and loss, 1:66
100:00

The position which the limestone belt holds in relation to the
valleys of the Delaware and the Flatkill, enables the farmers of
this favoured region to avail themselves of its fertilizing treasures,
throughout its whole range through Sussex, as it is nowhere
more than two or three miles from the two cultivatable tracts
which border it. But notwithstanding that the beneficial action
of lime on the soils along the river, and on the more gravelly lands
of the Flatkill and its adjacents hills, has been long admitted by
experience, there still exists on the part of many farmers, a singu-
lar indifference to this most important agent in agriculture.

Of the Circumstances which attended the Production and Eleva-
tion of the several Appalachian Rocks above described.

To comprehend fully that succession of actions which gave to
the northwestern side of New Jersey its present symmetrical
10

110

geology, would require us to go aside into some of the adjoining
States, where many of the phenomena essential to the inquiry
are best beheld, and to take more ample latitude in some descrip-
tions of a speculative kind, than is compatable with the design
and scope of the present work. I shall restrict myself, therefore,
in this place to a concise examination of a few points only, con-
nected with the origin and present position of the Appalachian
rocks.

The previous descriptions embracing but the five lowermost
members of the series and a subdivision of the eighth in the
ascending order, it is necessary for the discoverer to extend his
researches into the adjoining State of Pennsylvania to behold the
rest of that enormous group of strata, whose elevation from the
bed of what I have ventured to term the Appalachian Sea, gave
to a large part of the eastern half of our continent nearly its pre-
sent configuration.

He will then perceive, in the first place, two important forma-
tions, absent from the series, as it is developed in Sussex and
Warren, but of great thickness and vast range in other parts of the
Appalachian chain. These occupy a geological position between
the top of the red shale and sandstone rocks, Formation V., and
the bottom of the fossiliferous limestone of Formation VIII. The
lowest of these, Formation VI., is a bluish limestone, very analo-
gous in aspect and composition to that which ranges between the
Wallpack Bend and New York. The next, Formation VII,
whose true place, when all are present, is between these two
limestones, is a coarse white sandstone, of very distinctive
features.

Above the fossiliferous limestone of the Wallpack Bend, or lower
member of Formation VIII., rest the olive and brownish slates of
Formation VII, forming a stratum of great thickness, which
extends over a belt of many miles in breadth northwestward
from the Delaware.

Pursuing the same ascending order, and tracing the rocks in the
same northwest direction to the Coal Measures of the Wyoming
basin, we meet next with the red shales and argillaceous red
sandstones of Formation IX.

Overlying these are the white and gray siliceous sandstones

111

composing Formation X., then another series of red shales and
soft argillaceous red sandstones, constituting Formation XI.; and
upon these are the coarse quartzose conglomerates of Formation
XII., surmounted by Formation XIII., or the anthracite coal
measures. This last formation, or its equivalent, the bituminous
coal measures further west, occupies the highest place in the
series of our older secondary or Appalachian rocks.

The several members of this multifarious group of strata give
evidence, from their mutual parallelism, to which there is but the
one local exception in the unconformable contact near the Hudson
between Formations III. and IV., that they are the results of one
strictly continuous series of sedimentary actions.

Though the chemical agencies which precipitated the lime-
stones, and the various currents which introduced into the bed
of the same great sea the mechanically suspended materials
of the land, gave place to each other in frequent alternations, or
underwent, from time to time, a total change, yet do we never
find those geological proofs which would indicate an interruption
in this prodigious sequence of deposits. Commencing in the re-
mote period, which also saw the accumulation of the silurian
strata of Europe, their precipitation, unlike that of the latter, was
continued, unarrested by any widely influential physical revolu-
tions, to the close of that remarkable epoch which witnessed the
exuberant vegetation of the coal; whereas, in many portions of
Europe an interval of unascertained duration must have elapsed
between the elevation of the silurian deposits from their oceanic
bed, and the beginning of the new order of things which brought
together the materials of the great carboniferous formation. In
the region of the Appalachian rocks no pause occurred in the
train of sedimentary actions by the elevation and resubmersion of
any part of the vast secondary sea. We therefore find, in con-
firmation of the other proofs of the absence of such revolutions
during the accumulation of the Appalachian strata, that the fossils,
the remains of the organic races of that sea, and its shores, exhi-
bit a gentler gradation in the changes which they have under-
gone as to species, comparing them in the different formations of
the series, than is presented when we compare the silurian and
earboniferous fossils of Europe.

112

The conglomerate character already stated, as belonging to
certain portions of the Kittatinny limestone, would seem con-
clusively to imply, that perfect regularity or quiescence of action
did not prevail during the second epoch of the Appalachian
period. And the fact of the superposition of the sandstones of
the Shawunkunk Mountain wnconformably upon the slates of the
Kittatinny Valley, near the Hudson, is an evidence of another and
seemingly more extensive disturbance, terminating the third epoch.
To the turbulent interval which immediately resulted and brought
together the coarse siliceous materials of the fourth formation,
succeeded the relatively tranquil eras, as evinced by the nature
of their strata, of the fifth, sixth, seventh, eighth, and ninth rocks
of the series; then followed evidently two epochs of widely
diffused agitation, along the Appalachian shores, the tenth and
twelfth.

The heterogeneous nature of the conglomerates visible over
an immense space along the mountain chain of the middle
and southern States, goes plainly to establish the extensive
changes in the physical geography which were taking place, in
preparation, as it would seem, of that wholly new state of the
surface, which so clearly characterizes the last and most striking
interval of all, the epoch of the coal.

It is not a little curious, as casting additional light on the
occurrence of a movement of elevation in the region of the
Kittatinny Valley, at the close of the third epoch, that the rounded
fragments of the slate of Formation III., and of the chert of
Formation II., mingled with the quartz pebbles from the primary
rocks still further east, occur in considerable abundance in both
of the higher conglomerates, but especially in that which
composes Formation XII., encompassing all the anthracite and
bituminous coal fields. These fragments of the secondary rocks
suggest this inference, inasmuch as they show that part at least
of the slate and limestone formations had already been lifted out
of their parent waves, and that the rocky strata of the land
were exposed to the denuding agency which broke and rounded
them into pebbles, to form a portion of these later conglomerate
deposites.

As the conformability of the Kittatinny sandstone to the slate

113

is presented throughout their whole great range, across New
Jersey and Pennsylvania, and is only locally interrupted in New
York, the inference seems just, that much of the Kittatinny
Valley continued, at least to a late date in the Appalachian period,
beneath the waves. But the geological phenomena of the primary
chain southeast of the valley, go to show, with equal force, that
from that quarter probably came the principal portion of the
fragments of Formations I., II., and III. These, rounded by attri-
tion while on their journey, now constitute an interesting part of
the pebbles of Formation XII.

Respecting the precise geological dates of all the great anti-
clinal axes, the results of the enormous elevatory actions which
have upheaved the Appalachian strata from out of their ancient
sea and given them their present inclined positions, it would be
idle to speculate in the present imperfect state of our information.
But the whole evidence yet collected on the subject, manifestly
leads us to this striking generalization, namely, that one great
and general disturbance of the strata terminated the epoch of the
coal. Comparatively sudden, and immeasurably more energetic
than those that preceded it, it produced the almost simultaneous
elevation of the whole Appalachian chain, and was attended by
a commensurately violent denudation, from the abrupt and tre-
mendous drainage of the ancient Appalachian sea. There arose,
uplifting with them a vast belt of strata, the nearly innumerable
anticlinal axes of our Appalachian rocks, inclining and folding,
and breaking these into all their present irregular and contorted
attitudes.

114

CHAPTER III.

OF THE MIDDLE SECONDARY ROCKS.—GEOLOGY OF THE COUNTRY BE-
TWEEN THE BASE OF THE HIGHLANDS AND A LINE JOINING TRENTON
AND NEW BRUNSWICK ; ALSO, OF THE GREEN POND MOUNTAIN.

General Description—In the two preceding chapters, having
treated in detail the geological features of the primary and the
lower secondary rocks, we propose in the next place to describe
the middle secondary strata, embraced principally within the
third and remaining district of the northern half of the State.

In general aspect and composition, this group of rocks is one
of the most uniform and well marked in the country, and in de-
tailing its characters as they are beheld in New Jersey, we shall
be describing, in fact, the prevailing geological structure of the
whole belt, from the Hudson to North Carolina.

The formation consists of dark reddish-brown sandstone, almost
invariably argillaceous, of soft crumbly brown shales and coarse
conglomerates, the latter frequently of very heterogeneous com-
position. The prevailing, we might say the almost invariable
direction of the dip of the strata is towards the north, at angles
varying from 15° to 25°. The lower beds, or those which show
themselves along the southern edge of the tract, consist most
frequently of rather coarse sandstones alternating with red shales,
the sandstones being formed of somewhat angular fragments of
quartz, felspar, and other ingredients of the neighbouring primary
rocks, cemented by a paste of brown argillaceous matter. The
central parts of the series consist more exclusively of brown
shales and brown argillaceous sandstone, while the uppermost
beds, occurring along the northwestern margin of the formation,
have frequently the character of coarse conglomerates, made up
of pebbles derived from a very great variety of rocks, chiefly those
which occur at the base or on the sides of the adjacent primary
hills of the Highlands. Where a large proportion of the pebbles
are of limestone, and the cementing red earth which unites them
contains an adequate quantity of the same material, the rock

115

possesses the character of a marble, being susceptible of a good
polish, and resembling certain highly variegated breccias.

Though this conglomerate constitutes the uppermost member
of the red sandstone group in various places, both in New Jersey
and Pennsylvania, there are other neighbourhoods, for example,
near Bainbridge, on the Susquehanna, where it would seem rather
to occupy a position at the base of the series. All these rocks
of the middle secondary date, of which the argillaceous red and
brown sandstone is the predominant and characteristic variety,
appear, from numerous geological indications, to have been pro-
duced at a period subsequent to the elevation of the lower secon-
dary strata, including the coal deposits. They seem to have origi-
nated in a long narrow trough, which had its source as far south
at least as the eastern base of the Blue Ridge in Virginia and
North Carolina, and which probably opened into the ocean some-
where near the present position of the Raritan and New York
bays. Their materials give evidence of having been swept into
this estuary, or great ancient river, from the south and southeast,
by a current producing an almost universal dip of the beds
towards the northwest, a feature clearly not caused by any up-
lifting agency, but assumed originally at the time of their deposi-
tion, in consequence of the setting of the current from the opposite
or southeastern shore.

Numerous ridges and dikes of trap, some of them many miles
in length, traverse the area occupied by this formation in New
Jersey. The date of their appearance at the surface was mani-
festly subsequent to the deposition of the red argillaceous strata
through which they have burst, overflowing, while in the melted
state, the adjacent beds, and greatly altering their texture, colour,
and mineral aspect.

In what exact period during the secondary ages of the earth’s
geological history, this widely-diffused series of sedimentary
strata, and their accompanying igneous rocks, originated, we are
at present unable to determine with strict scientific precision, but
we are not without data for a somewhat satisfactory approxi-
mation.

The organic remains hitherto discovered are extremely few,
and the evidence they afford is not sufficient to establish within
near limits the era to which these strata should be referred.

116

They consist merely of a few rather imperfect relics of one or
two species of fishes, some indistinct impressions of fucoides, or
other aquatic vegetation, and occasional thin bands of a Ligniform
coal, in which the fibrous structure, apparently that of the wood,
is traceable. The other organic remains, particularly of the
fishes, imply a date somewhere intermediate between that of the
coal and that of the greensand, and indeed suggest it as
probable that the deposition of these beds commenced at an
early period after the elevation of the carboniferous and other
strata of the Appalachian series. That they are not so recent as
the greensand or newer secondary strata of the State, is proved
by their passing unconformably beneath that group, along the
whole of their common boundary, from near Trenton to the Ra-
ritan river, and that they are more modern than the coal is, I
think not less conclusively shown by their reposing unconform-
ably, and without signs of disturbance, upon the lower members
of the Appalachian rocks, in districts of the country where the
uptilting of these, and of the carboniferous strata at the top of the
same series, has obviously been contemporaneous.

A remarkable feature in the stratification of the whole of this
red sandstone belt, is the almost invariable inclination of its beds
to the northwest or north, towards the base of the Highlands,
where the older secondary strata are to be seen in many places
with a steep southeastern dip, passing beneath these newer rocks,
which therefore abut against them in the opposite direction. Had
any portion of these red rocks been produced at a period previous
to the last, and incomparably most violent disturbance, which
shook the great Appalachian basin, and which originated most,
if not all, of the principal axes of elevation in the Highlands
and the region to the northwest, laying bare the coal and all its
attendant rocks, it is extremely difficult to conceive how they
should have remained unaffected in their gentle northwestern

inclination.
Later, therefore, than the carboniferous rocks, and earlier

than the greensand, the most appropriate title claimed by this
group of strata, would seem to be that of the middle secondary
series. Though they present an obvious analogy in general
aspect and composition to the new red sandstone rocks of Europe,

117

and may in fact have originated somewhere about the same
epoch, yet I much prefer the above designation in the present
stage of geological research, because the other name* involves
the notion of an identity of age, which, from the singular paucity
of organic remains in the American group, may probably never
be buacapiibie of demonstration.

The whole middle secondary series, even where we find it, as
in Pennsylvania, presenting its most varied composition, is divi-
sible strictly into not more than three separate formations, the
lowermost and uppermost of which are conglomerates, while the
middle one, the main body of the series, is composed of the
ordinary red sandstone and red shale. In New Jersey, we find
the whole properly classified to embrace but the two upper of
these divisions, the red sandstone portion, and the uppermost
conglomerate, usually calcareous.

Adopting, in conformity with our general plan, the ascending
order, we shall therefore describe in the three following sections :

I. The red argillaceous sandstone formation.

I]. The variegated calcareous conglomerates.

Ill. The trap rocks intruded among and overlying both of
these deposites.

SECTION I.
Of the Red Argillaceous Sandstone.

Geographical Range-——The southeastern margin of the red
sandstone formation coincides, from the northern State line to the
mouth of Newark bay, with the eastern boundary of the State.
Emerging from beneath the range of trap rocks called the Pali-
sadoes, on the west shore of ithe Hudson, it skirts the river and
its bay the whole distance, in fact, from Stony Point, in New York,
to the outlet of Newark bay, called the Kills, or Killvan Kiehl.
Between this spot and Perth Amboy, the edge of these rocks
crosses Staten Island.

From Perth Amboy, we trace it along the north side of the

* Employed by Professor Hitchcock, for the corresponding rocks in the valley of
the Connecticut river. See Report on the Geology of Massachusetts.

118

Raritan river, which it crosses nearly opposite Lawrence’s brook.
Its course thence is along this latter stream for several miles,
until it is interrupted by a prolongation from the ridge of trap
rock which passes south and east of the Sandhills. On the
south of this belt of trap, the sandstone is again seen near the
head of Heathcote’s brook, from whence it takes an almost
westerly course to Kingston. Here its margin deflects south,
keeping a little to the southeast of the Raritan canal, to the head
of the Shipetaukin swamp, the northwestern edge of which it
pursues hearly to the junction of the Shipetaukin with the As-
sunpink, from whence to the Delaware river, a course of about
five miles, it follows the northwest border of the Trenton belt of
the primary strata.

The northwestern border of the formation, commencing at the
State line, pursues for several miles the course of the Ramapo
river, in contact with the primary, until it is fringed by a short
narrow belt of the overlying calcareous conglomerate, east of
Pompton. From this place, its route is again along the primary
strata, by the base of the Pompton Mountain to Montville, where
it is a second time overlaid on the north, by a small tract of
conglomerate.

From Montville we follow it, abutting against the primary at
the base of the Trowbridge Mountain, to Mendham Valley,
where it is interrupted for a narrow space by a belt of the
limestone of Formation II. of the older secondary series, which
it partially overlaps on its eastern side from about a mile west of
Mendham to Pepack. From this point its course is to the
Lamington river, and it is for the third time covered on its
northern side by the calcareous conglomerate which borders it in
a nearly continuous belt, passing New Germantown, to a spot
nearly north of Lebanon, on the turnpike. Curving around the
base of a small hill of trap, and another of gneiss, it next skirts
the edge of the tract of limestone of the south branch, where its
range is nearly westward along the limestone, by Perryville and
Pattonburg. In the neighbourhood of the Old Hickory Tavern,
it meets the gneiss at the foot of the Musconetcong Mountain.
About two miles beyond that spot, about the head of Milford
run, it is once more, for the fourth time, bordered by the superior
beds of the calcareous conglomerate, lying here at the foot of

119

the Musconetcong Mountain. Following the southern edge of
this narrow belt for about six miles, it finally quits the State by
crossing the Delaware river, near the mouth of Gallows run.

Composition and Structure-—While the prevailing and dis-
tinctive rocks of this formation are a dark brownish-red sand-
stene, and a soft and friable argillaceous red shale, it presents a
considerable diversity, especially among its lower beds, both as
respects its aspect and composition. In some parts of the series,
we find the argillaceous matter so predominant, that certain beds
assume almost the character of a homogeneous consolidated clay,
of a brown or dark purple colour, in which the laminations are
hardly discernable. On the other hand, the rock is not unfre-
quently composed mainly of sand, cohering into a true arenaceous
sandstone, by a slight amount of clay, usually red, but sometimes
white. In these cases it often contains a notable quantity of
mica, and is then a red flaggy sandstone, easily divisible in the
plane of stratification. In the inferior part of the formation,
beds of rather coarse and heterogeneous sandstone passing into
conglomerate, are not unusual. But the pebbles rarely make up
the chief part of the mass, and the larger kinds are somewhat
sparsely scattered, in the midst of what ought rather to be
termed a coarse and angular sand. The materials of these beds
seem to indicate a derivation from the contiguous primary
rocks, southeast of the formation, consisting principally of rather
angular grains of quartz and felspar, the latter most usually
passing by decomposition into clay or kaolin, together with a
less proportion of mica, and a little of the red argillaceous matter
so predominant in the formation. We sometimes find in the
coarse conglomerates, besides the abraded fragments of the
primary rocks, flattish pebbles of the red shale, which give to the
rock a rather mottled aspect.

An accurate conception of the diversified contents of this
extensive formation will be best conveyed by a somewhat
detailed description of its several portions, as they are exposed
along a section transverse to the strike of the beds. I shall
select the district bordering on the Delaware river, where the
series is more entire and better developed than in any other
tract of the State, and treat of each natural division in succession
as it presents itself in the ascending order. Commencing, there-

120

fore, with the lower margin of the formation, about one mile
northwest of Trenton, we find a well marked belt of strata occu-
pying a breadth of about two miles, between that point and
Hill’s Creek, its northwestern limit. ‘This consists of conglome-
ritic sandstones of the kind above referred to.

The materials of this lower set of rocks are pebbles and grains
of sand of the same minerals which compose the primary strata,
upon the upturned edges of which these rest. The rounded
fragments are from the size of coarse sand to an inch in diameter,
and comprehend grains and pebbles of quartz, some of which are
of the semi-transparent, partially opalescent kind, pretty abundant
in certain strata of the gneiss. Associated with the quartz there
is much felspar, white or yellowish, and partially decomposed ;
also, a small share of mica and a considerable quantity of horn-
blende. Throughout some of the strata there is a greater or
less proportion of hydrated oxide of iron, dispersed in minute
yellow specks. The decayed condition of the felspar, and the
stains from the oxide of iron, impair to some degree the value of
these rocks for the purposes of architecture. The dip of the
beds is to the northwest about 20°. A want of parallelism in
the planes of stratification, and some minor irregularities, inter-
fere with the value of many of the quarries in this range, by
preventing that uniformity of structure which building stone,
for many purposes, must have. <A good display of these rocks,
in all their distinctive features, is to be witnessed in Dean’s
Quarry, a mile and a half from Trenton, upon the feeder of the
canal. The same varieties show themselves on the Delaware
and Raritan Canal, about six miles northeast of Trenton, where
the beds agree in all particulars with these inferior strata along
the Feeder.

Overlying these more heterogeneous rocks at the bottom of the
formation, there succeeds a belt of a somewhat different character,
having a breadth of about two miles, from Hill’s Creek to the
stream at Abner Scudder’s. The prevailing rock is a coarse-
srained pinkish sandstone, consisting of transparent quartzose sand,
with numerous white grains or specks of somewhat decomposed
felspar, and small flattish pebbles or flakes of the more argilla-
ceous kind of red sandstone. The chief ingredient in this rock

121

is siliceous santf, either transparent and white, or stained yellowish
by oxide of iron. The predominant reddish colour of the rock is
due to the minute particles and fragments of the red shale which
it contains. The beds here described yield altogether the best
building material upon the Delaware. The rock is pretty exten-
sively quarried at the State Prison Quarry, Green’s Quarry, and
Hill’s Quarry, and upon the opposite side of the river at Yardley-
ville. Its stratification is usually very regular, and it is easily
wrought; and some of it seems capable, from its composition, of
resisting decay from atmospheric sources. This and the next in-
ferior group are discernible over a considerable range, pursuing a
direction nearly parallel to the canal towards Princeton, beyond
which they disappear beneath the overlapping strata of the upper
secondary or greensand series, a little to the east of Stony Brook,
and south of Kingston.

Between the stream at Scudder’s, five miles above Trenton,
and the small stream above the Alexsoeckin creek, near Centre-
bridge, the next extensive belt is embraced, occupying a breadth of
many miles. The rocks of this portion of the formation are well
exhibited near the Delaware, having been artificially excavated
in numerous places to make room for the bed of the Feeder of
the Raritan canal. They consist principally of those varieties
which form the usual and predominant materials of the whole
formation both in New Jersey and the adjoining States. The
ordinary species is a rather fine-grained brown or red argilla-
ceous sandstone, varying between soft argillaceous shale and
hard arenaceous and micaceous sandstone.

The colour, though most usually red, is sometimes dull bluish,
or greenish. Much of the rock exhibits cross joints, in great
number and regularity, and gives proof of its having been some-
what consolidated by an elevated temperature, if we may judge
from its compactness, its baked aspect, and the ringing sound
which it returns when struck, and from the extent to which it is
divided by these cross joints. With one single exception, in its
whole breadth along the Delaware the dip is invariably to the
northwest, at about the usual inclination of nearly 20°. The
exception referred to, occurs between Alexsockin creek and the
ridge of trap about a mile above it, where the dike has burst up
through the stratified rock and thrown it out of its usual inclina-

11

122

tion, and caused it to dip to the south and southeast. This
disturbance of position does not, however, prevail over perhaps
more than half a mile; and it is singular enough, that adjacent
to and between the three other bold ridges of trap which cross
the strata nearer Trenton, no similar displacement of the prevail-
ing dip has taken place. I may mention in this place, the same
interesting fact in connection with nearly all the principal out-
bursts of trap rock in the State, which produce no disorder in the
original attitude of the strata, though conclusive evidence will be
offered presently, that the trap must have issued through the stra-
tified rocks after their deposition. The stratified sandstone rises
almost to the top of Goat Hill on its eastern slope, dark and altered
in texture, but preserving its ordinary dip to the northwest.

Upon the northwest side of the large ridge of trap called Goat
Hill, there have arisen changes in the mineral contents and struc-
ture of the adjacent strata which are highly curious and impor-
tant when regarded in a scientific point of view. I allude to the
existence in the sandstone of a profusion of nodules and crystals
of epidote, tourmaline, and other minerals hardly ever found but
in igneous and volcanic rocks, but caused here by the heating
influence of the vast mass of trap, as it issued from the interior,
in a molten state. When treating of the trap rocks of the red
sandstone region generally, I shall dwell more at length upon
these interesting mineralogical changes.

This broad tract of argillaceous red sandstone and shale is in-
tersected in its range to the northeast by the valley of the Rari-
tan, where its beds are finely exposed to observation the whole
distance from Perth Amboy to Boundbrook. To the north-
east of the Raritan, nearly the whole of that part of the middle
secondary region included between Staten Island and the Hudson
on the east and the trap ridges on the west, consists of this divi-
sion of the formation. Resting upon this rather uniform portion
of the series, we find near the Delaware another somewhat more
varied set of strata extending between the small stream below
Centrebridge and the Wickhecheoke, about two miles above its
mouth. They consist of a series of alternating red sandstones
and coarse yellowish conglomerates, occasionally divided by
narrow beds of the softer argillaceous red shale. These conglo-
merates resemble closely those which occupy an inferior position

123

in the formation, and which appear within three miles of the gneiss
at Trenton. A large portion of the pebbles, which frequently are
half an inch in diameter, consist of quartz and felspar; the latter
occasionally in a decomposing state. With these are mingled
flatter pieces of red shale, the whole being bound together by a
small amount of ferruginous matter acting as the cement. Much
of this latter rock is merely a coarse sandstone, and in the vici-
nity of Centrebridge, and at intervals for a mile and more above, it
occurs of a quality excellently fitted for architectural uses, having
been fully tried in the bridges upon the upper end of the Feeder.

This rather arenaceous part of the formation, extends nearly
to the mouth of the Lockatong, if we follow the bend of the river.
Commencing a little above that stream, we meet with an elevated
table-land, the surface of which is about four hundred feet above
the Delaware. At the valley of the river this is about three miles
wide, but it expands towards the northeast, until it reaches the
valley of the South Branch of the Raritan. Its lower edge is traced
by a line, commencing at Bull’s Island, and passing west of Ser-
geantsville and Flemington. Here it bends to the north to follow
the South Branch to within three miles of Clinton. The upper or
northwestern limit is less clearly defined, as the highly indurated
strata pass, by nearly insensible shades in sorne places, into the
less altered rocks of the tract to the northwest. An approxima-
tion, however, to its boundary, will be had by drawing a line
from a little below Smithsville, on the Delaware, through Pitts-
town, to near the south branch of the Raritan.

Throughout this area, the rock preserves a moderately uniform
external character; being a highly indurated altered shale and
sandstone, the prevailing colour of which is a very dark dull blue,
sometimes a deep gray, and sometimes an olive-green. It has a
great tendency to split into rhomboidal fragments, with a some-
what splintery fracture ; and certain varieties yield, when struck,
a clear ringing sound, which has procured it the name of clink-
stone in the neighbourhood.*

The tract where this rock exists, goes in Hunterdon county
under the name of the Swamp, owing to the wet character of the
prevailing soil. Little or no true trap rock is visible in the dis-

* True clinkstone, or phonolite, is a felspar rock of the trap family, usually
fissile, and is sonorous when struck; whence its name.

124

trict, except along the southern border, where, as for example,
northwest of Flemington, it may be seen following the direc-
tion of the altered strata. It is likely that numerous dikes of
trap do exist, especially next the southwestern limit of the table-
land, but concealed beneath the soil, or perhaps existing as narrow
injected veins, not reaching the surface of the rock. The regular
stratified structure and northwestern dip of the strata seem,
however, not to have been changed, even where the rock appears
to have undergone the most decided alteration in all its external
features from the extremely elevated heat, to which it has evi-
dently been subjected since its original deposition. There is a
frequent alternation of the highly indurated beds with others, exhi-
biting but little departure from the commoner features of the red
shale and sandstone.

In the range of country northeast of this tract, the strata, ex-
cept where intersected by some trap ridges, hereafter to be men-
tioned, seem to have sustained no corresponding alteration of
texture and colour; nor are the changes which appear in the
rock for a small distance from the trap which occurs in that
region, of precisely the same nature as witnessed in the strata of
the Swamp.

The next belt of the formation which we meet with in our pro-
gress northwestward, commences at the verge of the altered or
indurated rocks of the Swamp, and extends nearly to the Nischi-
sakawick creek.

In a part of the series the rock is a compact fine-grained, but
somewhat argillaceous, red sandstone, splitting into regular flag-
stone ayers, which render it a convenient building stone, for
which purpose it would seem to be, in other respects also, well
adapted. Its colour is a brighter red than that which distinguishes
the set of beds that next overlie it.

Between the upper border of this more arenaceous tract, and
the southern edge of the variegated calcareous conglomerate, one
mile north of Milford, the predominant material is a very argilla-
ceous sandstone, with much soft friable shale, the whole being of a
deep reddish-brown colour. This extends over a width, measured
along a straight line parallel with the river, of about four miles.
The Nockamixon cliffs, upon the Pennsylvania side of the river,
exhibit a fine display of these upper beds. The angle of dip to

125

the northwest is very gentle, though considerably greater than it
seems to be from looking at the face of that precipitous escarp-
ment, the line of which is not sufficiently in the direction of
the dip to make the full degree of inclination apparent. The chief
part of the beds in this portion of the series are apparently arena-
ceous enough to furnish a very good sandstone for the ordinary
purposes of architecture.

In other parts of their range, these beds, lying immediately
below the conglomerate, are generally of the composition exhi-
bited near the Delaware. Near Pompton, however, where the
very top only of the series is exposed, the red sandstone and shale
occur in somewhat different features. In a quarry near that
place, the red sandstone may be seen of its ordinary character,
alternating in thin beds with a very heterogeneous fine-grained
conglomerate, made up of a great variety of materials, and pre-
senting, as it were, a miniature of the variegated conglomerate
above it. These sandstones are parted by very thin layers of the
soft shale, almost in the state of a compressed red clay. At the
dividing surface of the harder and softer layers, may frequently
be found organic impressions of a class evidently belonging to
some of the older aquatic tribes of the vegetable kingdom, appa-
rently fucoides.

Upon these sandstones there rests a thin bed of a gray siliceous
slate, very schistose, though of too coarse a texture to warrant
its being usefully applied. Besides the sand in its composition,
there is a moderate proportion of mica. Its laminz coincide with
the planes of stratification; the thickness of the whole mass is in-
conderable. The variegated conglomerate of this neighbourhood
rests in a conformable position upon this slate. All these rocks
dip to the northwest.

Having in the foregoing sketch described the several subordi-
nate members of the red sandstone formation, as we find them
developed along the valley of the Delaware, both in their ordinary
condition and in their more or less altered state as affected by the
neighbouring trap, let us in the next place follow some of the
more continuous of these, in their range across the State towards
the New York line. In consequence of the modification of tex-
ture which some of these rocks have received, by the nume-
rous outbursts of trap, by which the northwestern half of the

Ds

126

region, more particulariy, has been invaded, it becomes impossi-
ble to trace with any accuracy the limits of the several subdivi-
sions, even presuming them all to have been once continuous
strata; I shall, therefore, merely attempt an account of a number
of localities, referring the beds described as nearly as practicable
to their respective belts, as seen along the Delaware, and in doing
this shall observe the usual ascending order, proceeding from the
southeastern members of the formation to the northwestern.

Advancing from the Delaware towards the northeast, the first
or lowest beds, reposing on the gneiss rock near Trenton, re-
tain their coarse heterogeneous composition until they pass
beneath the marshes of the Shipetaukin creek, and the canal
south and east of Princeton, beyond which they are buried by the
overlapping white sands and clays of the upper secondary series.
On the declivity, or low escarpment, which bounds the valley of
Stony Brook, near Princeton, about a mile southeast of the town,
we find, near the canal, a gray arenaceous sandstone, which ap-
pears to constitute the upper part of this division, being overlaid
by the more argillaceous and reddish group.of beds next north
of it. The rock at this place has been quarried, and supplies an
excellent building stone. The main edifice of the college, and
several recently erected edifices, in Princeton, are constructed
of it.

The next belt, extending on the Delaware from Hill’s creek to
Scudder’s creek, crosses the canal near Kingston. Here, and
along the southern side of the Sand Hills, it encounters the trap
ridge, prolonged from Rocky Hill, its beds undergoing some inte-
resting tmodifications of structure, which will be more fully de-
scribed when we come to treat of the trap rocks specially, and
the changes induced by them.

Viewed comprehensively, the next subdivision of the formation
should embrace the entire series of argillaceous red sandstones
and shales, included between these arenaceous rocks and the
calcareous conglomerates which overlie the whole, for it is ob-
vious that some of the varieties separately described as occurring
near the Delaware, owe their peculiar texture to igneous actions
of a merely local nature. Such is the case with the thick group
of beds composing the tract called the Swamp. Other subordi-
nate strata, like the coarse sandstones near Centrebridge, would

127

appear not to have a sufficiently continuous range across the
State to make it necessary to carry out the subdivisions of the
formation, as they were detailed when describing the rocks along
the Delaware.

Convenience, however, recommends that we consider sepa-
rately the wide belt of argillaceous rocks, embraced between the
arenaceous ones of Scudder’s creek and the still coarser ones of
the vicinity of Centrebridge.

The inferior margin of this zone of strata, after passing by
Princeton, is prolonged to Lawrence’s brook, where it consti-
tutes also the southeastern edge of the whole middle secondary
region, being overlaid unconformably along the southern side of
that stream by the lowest of the upper secondary series. Beyond
the mouth of Lawrence’s brook, the same rocks extend every
where to the eastern boundary of the State, fringing the western
shores of the Raritan, of Staten Island Sound, and of the Hudson
river.

The upper or northwestern margin may be traced from the
stream east of Centrebridge, past Middlebrook, on the Raritan,
and thence along the eastern base of the easternmost principal
ridge of trap. The occurrence, in the neighbourhood of Pat-
terson, of a coarse siliceous sandstone and conglomerate rock
resembling that near Centrebridge, and the occasional appear-
ance of a similar material at points adjacent to the line designated,
seem to mark this as a boundary not altogether conventional.
Within the two limits thus traced, the almost invariable aspect of
the rock is that of a brownish red shale, including beds of a more
or less argillaceous and micaceous sandstone of a somewhat
lighter tint, some localities of which furnish good building stone
and flag-stone.

Between the Delaware and the Raritan rivers the unaltered
varieties of the rocks of this belt are seldom quarried, and present
but few features of either economic or scientific interest.

The altered portions, important in both these points of view,
will be described somewhat in detail when allusion is made to
the several ranges of trap with which they are connected along
the Raritan, where, as already mentioned, occur fine opportu-
nities for studying this portion of the formation.

At New Brunswick, the dip and structure of the red shale are

128

beautifully exposed on the bank of the canal for a mile above the
town, exhibiting the nearly parallel planes or laminz of deposition,
dipping with extreme uniformity to the northwest, at an angle of
about 15°. Some of the more argillaceous layers contain a con-
siderable amount of the carbonate of lime in small disseminated
crystals, also in the form of hollow nests, lined with crystals form-
ing bands of two or three inches thickness and of thin seams or
plates of satin spar, filling the fissures of the shale. The planes
of lamination are often marked by thin bands of a light bluish-
green calcareous shale, which owe their peculiar colour to the
iron so copiously present in the formation, usually as a peroxide,
but in these instances reduced to the condition of protoxide.
These bands are erroneously supposed to contain copper.

Northwestward, as far as Boundbrook, the stratum retains
very nearly the aspect which it exhibits near New Brunswick.
The only fact of interest is the gradual declension in the angle
of the dip towards the northwest. Between Boundbrook and
Middlebrook the rocks are well exposed on the south side of the
river by the excavations made for the canal. Here the dip
exhibits an unusual direction, being towards the southeast, but at
an angle not exceeding 5°. This change in the inclination of the
strata is not merely local, but prevails over an area of several
miles to the northwest and west, the whole way to the vicinity
of Pepack in the one direction, and the junction of the north and
south branches of the Raritan in the other. Tracing the dip
along the Millstone river, in a succession of fine exposures from
Griggstown towards its mouth, we perceive it to be to the north-
west, but gradually diminishing until we approach the Raritan,
where it becomes horizontal, and soon after assumes the contrary
direction, as beheld in the vicinity of Middlebrook. The line
of no dip or synclinal axis is traceable continuously from Bound-
brook, taking a west-southwest direction through Millton, or
Rogers’ Mills, to Flaggtown. Along the southeastern base of
the ridge of trap, which extends from the Bridgewater Copper
Mine towards Pluckemin, the southeastern dip is towards the
hill obliquely, indicating that it is not a result of the protrusion
of the trap, which, throughout the region, has usually exerted
very little influence in disturbing the direction assumed by the
red sandstone formation at the time of its deposition.

129

An explanation of the probable cause of the unusual dip
assumed by the strata in this quarter will be attempted under
another head, while discussing some of the physical circum-
stances which attended the formation of this whole series of
middle secondary deposits.

Extending our observations northeast of the Raritan, we meet
with few features in the geology of this belt of the red sandstone
tract deserving of a special description, until we reach the neigh-
bourhood of Newark. The direction of the dip, wherever this
can be noticed, is towards the northwest at an angle rarely
exceeding 15°. Between Boundbrook and Scotch Plains, along
the valley of Greenbrook, so general is the covering of diluvial
matter for three or four miles east of the base of the first trap
ridge, that it is impossible to ascertain whether the synclinal axis
passing from Flaggtown to Boundbrook is prolonged in this
direction. The existence of a regular northwestern dip in the
strata between the first and second trap ridges, at points north of
Plainfield and Scotch Plains, renders its continuation far to the
northeast of the Raritan very improbable.

The surface of the formation is covered throughout nearly the
entire distance between Rahway and Plainfield, by a deep sandy
loam, imbedding occasionally loose fragments of sandstone and
some rolled masses of primary rocks derived from the Highlands.
A level, sandy plain, stretching for some miles in length, from
northeast of Scotch Plains to southwest of Plainfield, exhibits a
succession of fine farms, and several thriving villages. An abun-
dance of excellent water is usually procured by descending about
fifteen or sixteen feet into the diluvial sand and gravel.

The country included between Rahway, Elizabethtown, and
Newark, on the east, and Scotch Plains and Springfield, on the
west, is very similar in its general aspect, being rather level, with
occasional gentle swells and undulations of the surface. The soil
is a fertile reddish sandy loam, well cultivated. Boulders and
loose fragments of rock are fewer on the surface here than a few
miles further towards the northeast. Throughout much of this
area the underlying rock is deeply covered.

Pursuing our course to the northeast, the sandstone is exposed
in a quarry above the village of Jefferson, in the immediate vici-
nity of the trap rock, dipping to the usual quarter, the northwest,

130

at an angle of between 12° and 15°. The main mass of the rock
in the quarry is a dull red siliceous sandstone, of a uniform
grain, having numerous interspersed specks of mica.

In the neighbourhood of Newark the more arenaceous variety
of the red sandstone is moderately abundant, affording much
good building stone. About half a mile north of the town
quarries are extensively worked, giving a good exhibition of the
composition and arrangement of the strata.

The rock here is for the most part a siliceous sandstone of a
dull brownish-red colour, and an even grain. It contains a little
mica. Alternating with the beds of sandstone are thinner layers
of red, argillaceous shale, which soon disintegrates upon exposure
to the air. In some of the lower beds are thin plates of carbona-
ceous matter, and a minute seam of a pure ligniform coal
between one and two inches in thickness. The dip of the
planes of deposition in this vicinity is about 10° to the northwest.
Between Newark and Paterson the rock displays little or no
departure from the usual character which it preserves further to
the southwest in the same belt, being the usual mixture of red
shale and more or less arenaceous red sandstone. Its dip is
every where the same, or northwest between 10° and 15°: no
change in this respect is perceptible as we approach the trap
ridge to its west. Between East and West Bloomfield villages
are some quarries affording a moderately good building stone.
The rock is the common red sandstone of the region divided by
thin interposed bands of red shale. It displays a northwest dip,
the angle being 12°. In one of the sandstone beds there is seen
a thin layer of coal, of a variety approaching to lignite.

Near the Passaic Falls at Paterson, the sandstone is seen
under a considerable diversity of aspect, varying from a coarse
conglomerate, containing numerous pebbles of white and reddish
quartz, limestone, and other rocks, to a close-grained, siliceous
sandstone, moderately well adapted for building stone. There
are occasional interposed layers of red shale. This conglomerate
and sandstone rock bears a near resemblance to that on the
Delaware below Centrebridge, and would appear to occupy
a corresponding position in the general series of beds which
together constitute the red sandstone formation.

To the southwest of Paterson, at the Little Falls of the

131

Passaic, a sandstone of a somewhat different composition and
appearance occurs on both sides of the river, though in the
immediate vicinity of the trap dike of the second mountain; it
preserves its almost invariable dip to the northwest, which is
here at an angle of from 10° to 15°. This sandstone is of a very
superior quality, both for the purposes of architecture and sculp-
ture, and the quarries which have been opened furnish blocks of
almost any dimensions. One of these quarries has been con-
ducted under the direction of Mr. Thom, the celebrated sculptor,
who has found in it a material extremely well adapted to receive
the admirable delineations of his chisel.

From Paterson eastward to the Hudson, and northwestward
to the New York line, the formation exhibits little or no departure
from its ordinary type, as respects its composition, structure, and
the direction and degree of dip of its planes of stratification.

The upper or northwestern half of the red shale and sandstone
formation, extending on the Delaware, between the mouth of the
Lockatong and the overlying conglomerate at Spring Mills, and
between the first trap ridge and the foot of the primary hills in
the country north of the Raritan, is nearly identical in composition
with the belt already described; the chief departure from uni-
formity of structure in either district arising from the changes
induced by the numerous ridges and dikes of trap to be presently
considered. Adhering in this place to the plan proposed of pre-
senting a brief account of the formation in the different portions
of its range, by selecting a few characteristic localities where the
rocks are plainly disclosed in their prevailing features unaffected
by igneous agency, let us glance at the northwestern belt of the
formation beginning as before at the end next the Delaware.

To the west of the wide area of altered shales, composing the
tract called the Swamp, we find a zone of ordinary red shale and
argillaceous sandstone, in the prolongation of the Nockamixon
rocks on the Delaware. Between Evittstown and Mount Pleasant
these strata are well seen under their usual type, dipping regularly
and gently to the northwest. To the southeast and east of
Evittstown an arenaceous variety of the sandstone affords an
excellent material for architectural uses. Approaching Bap-
tistown, the rocks begin to manifest, by a change of colour and
texture, their proximity to the trap dikes of the Swamp.

1382

From that neighbourhood northeastward this portion of the
formation presents little that is worthy of record until we reach the
eastern side of the Round Valley Mountain. About a mile south-
west of the White Horse Tavern, and nearly opposite the curve
of the Round Valley Mountain, there occurs a rather singular
ridge of considerable elevation, extending southeastward from the
trap. On the southwest of this long ridge the beds of the red shale
have their prevailing gentle dip to the northwest, but immediately
after crossing it towards the White Horse Tavern, there is a
total change in the direction of the dip, which is to the northeast,
at an angle exceeding 40°; the change is sudden and strongly
defined. This ridge, apparently forming the axis of dislocation,
extending southeastward from the curve of the Round Valley
Mountain towards the Raritan, the angle of dip in the strata
gradually diminishes as we proceed north, or towards New Ger-
mantown, assuming a more eastern inclination, and becoming, east
of the Lamington river, the southeastern dip already spoken of.

In the valley of the Passaic river, east and south of the
trap ridge, called Long Hill, the shale and sandstone, in many
places, appear finely exposed for examination. ‘They constitute
an escarpment of some height on the southeastern declivity of
the hill, rising nearly half way up the steep ascent, exhibiting
great regularity of stratification, and an undisturbed dip to the
northwest, at an angle of 15°, directly towards the trap in the
body of the hill. In several spots along the base of this ridge the
shale has sustained a change of aspect from the heating action of
the trap. Being soft, friable, and, when wet, of a nearly black
colour, it has given origin to a mistaken notion in the neighbour-
hood, that these strata contain coal, and hence many fruitless
explorations have been undertaken here in search of that mineral.
In fact, it is said a company was organized, and expended $1000
in digging and boring for coal. A little geological knowledge
would have shown the absurdity of anticipating coal any where
in this red sandstone formation.

On the eastern bank of the Passaic river, at a point about a
mile and a half above Chatham, where the Morris and Essex
Railroad crosses the stream, the red shale has been exposed to
view in a quarry, from which the building stone for the viaduct
over the river was procured.

133

Beneath several feet of alternating bands of lead-coloured and
yellowish slate, lies a very extensive bed of compact red shale,
in thick and solid layers. This mass has evidently been partially
acted on by the elevated temperature of the adjacent trap dike
of Long Hill to its west.

It is traversed by natural joints, generally several feet asunder,
extending parallel with each other from northeast to southwest,
separating the whole into immense blocks and tabular masses,
which are readily cleft into pieces of any desirable size for
masonry. In many places the laminz of the rock are somewhat
contorted. ‘Towards the bottom of the quarry the material
acquires more of the character of a sandstone. The dip is at an
angle of 15° towards the west. On the same side of the Passaic,
about a mile above Chatham, near a mill, the sandstone is
again exposed to view by the erosive action of a small tributary
stream.

At Lindsay’s Mill, three miles southwest from Madison, denu-
dation has exposed the rock in many places. It has the aspect
of a thinly laminated shale, with layers of a bluish and yellowish
slate, containing cubical crystals of su/phuret of tron. A yellowish
ferruginous sandstone is also visible in one or two spots.

The indications at this place imply, that by removing the
overlying shale, a good building stone, which is much wanted
in this vicinity, might be procured. The dip in some places is
slightly irregular, being in certain spots. horizontal, and again
being directed eastward at an angle of not more than 5°.

A deep diluvial bed of sand and gravel covers the plain from
Morristown to the end of the ridge of trap, which extends north-
ward from Green Village by Spring Valley; but west of this
outburst of trap the sandstone appears. In the vicinity of New
Vernon the red shale is often exposed, dipping generaily at
about 8° to the westward. South of the last named village the
shale and sandstone display their ordinary features, although
they show in some places traces of alteration from their proxi-
mity to the trap. The same remarks apply to the vicinity of
Basking Ridge. East from this place, and northward from Long
Hill and Green Village, there is an extensive level tract called the
Great Swamp, consisting chiefly of meadow, the rocks here being
covered throughout by a wide deposit of diluvium.

12

134

North of Plainfield, the red shale occasionally shows itself be-
tween the first and second trap ridges. A clay is found here of
which good bricks are made. In the next little valley northeast of
this, and still between the first and second belts of trap rock, and
north of Scotch Plains, the red shale is well exhibited along the
banks of the stream, presenting a low but regular escarpment
in the hill side. About the middle of these beds of shale, and
running parallel with them throughout the whole face of the rock,
is a thin belt of Umestone, a material of unusual occurrence,
particularly in this central portion of the formation.

It is thinly bedded, in layers varying from an inch to six inches
in thickness, constituting together a bed between one and two feet
from top to bottom.

On the other side of the stream, in the northern face of a deep
ravine, a similar, in all probability the same, bed of limestone is
exposed for a considerable space. It is more massive than at
the other spot, being a solid seam between two and three feet in
thickness; above it and beneath it occurs the ordinary red shale,
the whole dipping to the northwest, at an inclination of about 12°.
The upper beds of shale along the whole valley, are here very
regular, but in the bottom of the ravine above mentioned, the
trap seems to have invaded the strata, inducing considerable
confusion. Besides producing much alteration in the shale and
sandstone, it has in places modified the limestone, giving rise to
a mass of white semi-crystallized carbonate of lime. These
unusual features, so easily understood by science, have led to
several fruitless mining enterprises in this neighbourhood.

On the northwestern side of the mountain, near the road from
a paper-mill, there is a quarry of slaty sandstone, furnishing an
excellent flag-stone. It is also used for tombstones, being both
neat and durable. It exhibits signs of having been baked by an
adjacent dike of trap.

Following the course of the Passaic, from Chatham to the
semicircular valley enclosed by the Hook Mountain, (laid down
on the map as ‘Towakow Mountain,) we pass over a wide and
nearly level tract of almost uninterrupted diluvium. But in the
recess of the Hook Mountain, the red sandstone sometimes
appears along its southeastern base.

About one-third the distance from its eastern to its western

135

termination, there is a quarry from which much good building
stone has been procured, though the rock is rather thin bedded.
Notwithstanding, that it is in almost immediate contact with the
trap of the Hook Mountain, the sandstone appears in this place
to have undergone very little change from igneous action, nor
is the usual northwest dip disturbed.

West of the Hook Mountain, between Parcipany and Mont-
ville, and again at Montville, we find the red shale and sandstone
formation retaining its prevailing aspect and direction of dip.
At Montville, it is overlaid by a coarse heterogeneous conglo-
merate, composed of very loosely cohering fragments.

The somewhat diversified character assumed by the shale and
sandstone, near its contact with the variegated calcareous
conglomerate of Pompton, near Ryerson’s, has already been
described in sufficient detail’ Beyond this last named point to
the State line, these rocks are occasionally exposed, but with no
peculiarities of composition or structure demanding from us any
special description.

The district east of the Ramapo river, for several miles is
extensively overspread with diluvial matter, imbedding nume-
rous bowlders of primary rocks, the whole having evidently come
from the elevated belt of primary hills and mountains, composing
the broad chain of the Highlands lying to the west and north.

Variegated Calcareous Conglomerates.

Description and Geographical range—This heterogeneous
though well characterized rock, may be regarded as a distinct
formation from the group of red shales and sandstones beneath
it, being the result of a wholly different train of physical causes.
It constitutes the uppermost member of the middle secondary
series, overlying the red shale along its northwestern margin, not
in a continuous belt, but in several insulated patches that range in
one general line, near the foot of the primary hills. In almost
every portion of its range, the materials of this rock are extremely
heterogeneous, consisting of pebbles or water-worn masses of all
sizes, from that of a man’s head down to that of a small pea,
belonging to most of the older formations discovered in the region.
A large portion of this very motley mass is made up of variously

P 136

coloured sandstone pebbles. Sometimes there is a considerable
mixture of pebbles from the primary rocks; and in certain parts
of its range, the stratum consists, throughout nearly the whole
thickness, of pebbles of limestone, firmly cemented by a limestone
paste. Usually, the cement or imbedding paste contains a sensible
proportion of the materials of the red argillaceous shale of the
stratum beneath. In fact, where the Baltimore and Ohio railroad
crosses this rock in Maryland, the chief part of the cement is
nothing else. ‘This admixture of red matter in the rock in New
Jersey is easily explained. ‘The harder sandstones and the lime-
stone have retained the fragmentary state, while the soft red shale
has been reduced to powder or mud, by the violent action which
biought together this vast mass of water-worn materials.

A large portion of the formation in its course across New
Jersey, exhibits all the characters of the rock which forms
the columns of the Hall of Representatives at Washington, and
which has received the name of the Potomac Marble. The most
northeastern locality of this rock which occurs within the State,
is on the Ramapo river, near the village of Pompton. It is
traceable in all its obvious features, in a belt of more than
a mile in length, passing in the immediate neighbourhood of
Ryerson’s. Here its actual contact with the inferior sandstone
formation was detected, and the conformability of the rocks
clearly ascertained. Over the red sandstone rests a bed of rather
thin siliceous slate, the upper portion of which is somewhat
calcareous; and immediately upon this reposes the very close
conglomerate containing a pretty large share of limestone pebbles.
This occurs near the Ramapo, a mile to the northeast of
Ryerson’s. The dip of the whole is to the west, the angle being
between fifteen and twenty degrees.

‘ine conglomerate is seen again with the same dip about half a
mile to the west of this, and contiguous to a ridge of gneiss, which
appears to have caused some local displacement of the neigh-
bouring strata. This is upon the border of the plain through
which the Ringwood stream passes. It seems altogether probable
that the difficulty of tracing the conglomerate more extensively
in this quarter arises, first, from the irregularities in the direction
of the strata, caused by the intrusion of the trap; and in the next
place, from the western part of the formation resting beneath

137
the deep covering of diluvium which forms these plains. At the
spot last mentioned, the conglomerate was disclosed by some over-
credulous miner in an excavation for silver ore, led astray by the
occurrence of very minute crystals of yellow sulphuret of iron.
The rock is nearly all limestone, and specimens which have been
polished, prove exactly identical in character with the Potomac
marble. The conglomerate is traceable along the side of the
Ramapo river, near Ryerson’s barn, where it has the same dip
and general composition as elsewhere, though it is less calcareous.

The next place at which we witness unequivocal traces of the
formation, is at the foot of the inclined plane, upon the Morris
canal, at Montville. It there forms the abutments of a mill-dam,
where it will be found to agree very strictly with the slightly cal-
careous variety which forms the lowest part of the stratum upon
the Delaware. At Montville the pebbles are often very large,
and consist principally of primary rocks and red sandstone, so
that it would be useless to attempt burning it for lime, although a
more calcareous layer may possibly occur nearer the top of the
stratum, or which is the same thing, a little farther to the north-
west, that being the direction of the dip of the stratum at this
place.

Another interesting belt of this formation is that which skirts
New Germantown upon its northwest, in a tract perhaps half a
mile wide and several miles in length, extending nearly as far north
as the Lamington river. At New Germantown it is an almost
pure limestone, and is somewhat extensively used for making
lime. The pebbles are of various shades of colour, blue, yellow-
ish, and red, and much of the cementing matter is tinged red. It
is susceptible of a high polish, and constitutes a beautifully varie-
gated conglomeritic marble. ‘The dip of the rock in this portion
of its range, is somewhat various in direction, but at a uniform
angle of about 20°. The usual diameter of the pebbles is about
an inch, though many are much larger. They are not fully
rounded, but occasionally exhibit edges and angles, though much
blunted and worn, as if by attrition. The superposition of
this rock to the red shale or sandstone series upon which the
village of New Germantown rests, is very evidently shown in its
vicinity. On the northwest side of the little valley which borders
the town, we see the conglomerate; while upon the southeast

12*

138

side we behold, within a few hundred feet, and dipping in the
same direction and at the same angle, the northwestern edge of
the red shale.

The relation of the calcareous conglomerate to the underlying
stratum is well shown on the route from Pepack to New German-
town, east of the Lamington river. The rock is generally a sili-
ceous conglomerate or coarse arenaceous sandstone, with some
thin layers of shale, all dipping at a moderate angle to the west
and southwest.

At New Germantown, a little north of the village, the red shale
is seen dipping westward, changed to a greenish-gray colour
near the brook by its vicinity to a narrow dike of trap. |

At the same spot an argillaceous limestone occurs, also dipping
westward and occupying a place in the strata a little Jower than
the red shale nearer the town. About a quarter of a mile to the
northeast of the bridge over the brook, are several quarries in a
field east of the road, exposing the calcareous conglomerate,
which is here used for burning into lime. Some of its pebbles
are very large, consisting of limestone of various colours, a small
proportion only belonging to other rocks. The cement is also
highly calcareous. The dip of the stratum at this place, is west
5° south, at an angle a little exceeding 20°.

Half a mile northeast from this is another quarry more recently
opened, exposing a calcareous conglomerate similar to that in
Ogden’s quarry, next to be mentioned. The beds have a gentle
dip towards the southwest.

Lying about three quarters of a mile still further to the north-
east, is Ogden’s quarry, at present the most extensive in the tract.
The cement uniting the pebbles is at this spot generally very
calcareous; it is of a reddish colour, and some portions are highly
stained by the brown matter of the red shale. ‘The aspect of the
rocks is singularly diversified, owing to the variety in size, shape,
and colour of the imbedded pebbles. Specimens may be obtained
here susceptible of a beautiful polish, and affording an ornamental
marble of considerable beauty and novelty of appearance. The
dip of the beds in this neighbourhood is eastward, at an angle of
20°. The conglomerate is not found beyond Ogden’s quarry, a
high ridge to the east seeming to arrest it in that direction.

About two and a half miles to the northeast, on the Lamington

139

river, a limestone appears; not, however, in the form of a con-
glomerate, but resembling that at Pepack and Mendham, and
belonging evidently to Formation II. of the older secondary
series. Between the Lamington river and the valley of the Pe-
pack, this limestone is again buried under a high ridge of the
arenaceous sandstone, which in this neighbourhood underlies at
a short interval the calcareous conglomerate.

Tracing the conglomerate westward, we find it next in a belt
separated by a space of about half a mile from the New German-
town tract. It commences on the Rockaway creek, a little north
of the road to Potterstown, and ranges near the foot of the gneiss
hills, for a distance of about four miles to a point a little north of
Lebanon, where it is intercepted by a low ridge of the gneiss.

In aspect and composition the rock here is very similar to that
at New Germantown, being equally, if not more calcareous, and
therefore well adapted for burning into lime. It has evidently
been much denuded, the surface being strewed with large, irregu-
larly-shaped blocks. ‘The dip, where it can be noticed, is towards
the northwest at a gentle angle.

As the farmers of this belt of country along the base of the
gneiss hills are becoming alive to the importance of lime in agri-
culture, a motive is furnished them for discovering this whenever
it may be found; and little doubt exists that excavations will dis-
close it in many spots where it is now hidden by the superincum-
bent soil.

Another smaller tract of this useful and curious stratum, pro-
tected from the general denudation, which has obviously removed
so large a portion of it along the base of the primary hills, exhibits
itself on the surface near a small stream, about two miles and a
half southwest of Clinton. Apparently inferior in order of strati-
fication is a siliceous conglomerate, met with north of the stream.
South of this there occurs a red shale, exhibiting considerable
local derangement of dip, inclining to the southeast at an angle
of 35°.

Alternating with this, and apparently underlying it, lies a cal-
careous slaty rock, also considerably disturbed; the prevailing
dip of which is also rather steep, and to the southeast. It con-
tains thin layers of moderately pure limestone. On the opposite
side of the stream and southward of the former beds only a few

140

hundred yards, is the calcareous conglomerate, having the same
composition with that north of Lebanon and New Germantown.
Its dip is apparently to the northwest.

Pursuing our course to the Delaware, we next meet the con-
glomerate in a belt of more than a mile wide, between Milford
and Spring Mills, coming to the river nearly opposite Gallows
run. It rests conformably upon the upper layers of the red sand-
stone, which it joins probably about one mile to the northwest of
Milford. Dipping to the northwest, or directly towards the
eastern base of the Musconetcong Mountain, its near proximity
renders the conclusion certain, that it meets the strata of the hill
in an unconformable position.

Upon the Delaware, the rock which immediately overlies the
argillaceous red sandstone, and soft argillaceous shale, is a siliceous
conglomerate of great thickness, which is finely developed along
the banks of the river for the distance of a mile, crossing the
strike of the beds at an acute angle. The principal part of the
pebbles in this portion of the formation are from the primary
rocks, being chiefly quartz. They present a great diversity of
size, varying from the dimensions of a pea to huge rounded
masses, weighing from sixty to one hundred pounds.

Higher up the river we meet with another conglomerate, the
representative of the true calcareous variety, differing obviously
in composition from that just described, from which_it is probably
separated by intervening beds of red shale. This upper con-
glomerate is a less finely cemented rock, and includes a con-
siderable proportion of calcareous matter, both in the limestone
pebbles and in the imbedding paste. ‘The fragments are less
rounded and water-worn than in the conglomerate below. Some-
what angular fragments of a bluish compact limestone are
frequent in the rock, while the siliceous mass exhibits but little
corrosion from atmospheric agency ; this more calcareous stratum
presents on its surface a loose cellular structure, showing innu-
merable pits and cavities, from whence the limestone pebbles
have been dissolved. A little below Johnson’s Ferry, the rock
near the road is thus greatly weather-eaten.

This upper calcareous conglomerate rarely occurs, except in
the neighbourhood of the regularly stratified limestone of Forma-
tion II., along the base of the primary hills. It is in this position

141

accordingly, that we find it upon the Delaware, where its beds,
observing a gentle northwest dip, abut unconformably against
the highly upturned strata of the older limestone, reposing with a
steep southeastern dip upon the primary rocks in the flank of the
Musconetcong Mountain. |

The more calcareous variety of this rock, where the cementing
matter is not too soft, affords a material of the highest beauty for
ornamental uses; and it is a subject of surprise that so little has
been done to call attention to its numerous applications. The
rock is frequently so exclusively composed of materials derived
from limestone, that it makes as good a lime by burning as many
strata which do not possess the conglomerate structure. It has
been in reference to this, its most valuable property, that I have
felt especially solicitous to fix as nearly as possible the range
which it pursues across the State, that farmers in the northern
portions of the red sandstone district, needing lime for the im-
provement of their agriculture, might be induced to seek it from
this formation, which, when it is sufficiently calcareous, is of
course the nearest source.

The theoretical views respecting the mode of origin of these
masses of calcareous and siliceous conglomerate which overlie
the red sandstone formation, suggested by their various geological
relations, will be presented in a subsequent section, after treating
of the trap rocks and the changes induced by them.

To that part of the Geology of the middle secondary region, I
now proceed.

Of the Trap Rocks, and Phenomena evincing Igneous Action.

Geographical range.—Between the Hudson and Delaware
rivers, the middle secondary or red shale region is traversed in a
longitudinal direction, from north-northeast to south-southwest,
by a number of nearly parallel ridgeg and dikes of trap rock,
some of which are of great length and uniformity of structure.
Some of these are nearly straight over a course of many miles,
others are considerably curved, and several again are of a nearly
semicircular form. The height of the larger of these belts is
about four hundred feet, while many have not more than half or
even one-fourth of this elevation. In one class of these ridges,

142

the entire hill consists of no other rock than the trap, the huge
weathered masses of which, covering the summit and flanks,
impart an aspect of extreme ruggedness. In other instances, the
predominant rock at the surface is the red shale, indurated, baked,
and altered in colour, by the excessive heat that has been ap-
plied to it, while the trap either does not appear at all, or has
reached the day only in a series of narrow dikes. The hills of
the latter class, have a more round and swelling contour, than
those consisting solely of the trap, and admit of tillage to a cer-
tain extent.

To enumerate the principal trappean belts of the region we
shall commence on the northeast with that called the Closter
Mountain. This long range follows the western shore of the
Hudson, from the Tappan Sea to Bergen Point, presenting a bold,
unbroken ridge, which overlooks the river in the lofty mural pre-
cipice of many miles’ length, known as the Palisadoes. The
next belts west of this are the two extensive parallel ranges
usually called the First and Second Newark Mountains. They
commence at the Passaic, near Paterson, and keeping east of
that river, pursue a course about south-southwest almost to its
source, observing a nearly straight line until they approach the
Raritan, where they curve, first gently westward, and after-
wards more abruptly northwestward. The more eastern of these
ridges is usually single; but the westernmost, especially near its
southern termination, where it takes the name of Stony Hill, is in
parts of its course double or even triple. West of the Passaic
and east of Pompton river, Preakness Ridge, with its spurs,
which united compose a continuous belt of trap, having almost
the form of a horseshoe, encircles the Preakness Valley.

Somewhat similar in shape is the next principal outburst of trap
rock called the Hook Mountain (Towakow on the map), which
has the form of a nearly perfect semicircle, embracing in its
concave the bend of the Passaic river, called the Horse Neck.

Still further to the southwest we meet several partial exposures
of the trap, in the ridges west of the Passaic, near Bottle Hill,
Green Village, and New Vernon, and in the more continuous belt
called Long Hill.

If we add to these the hill extending from south of Basking
Ridge to Pluckemin, immediately east of Mine brook, we shall

143

have enumerated all the conspicuous elevations of the trap north
of the Raritan river.

Between the Raritan and the Delaware we have first the
Rocky Hill range, commencing, properly considered, on Law-
rence’s brook, east of the Sand Hills, and extending across the
Millstone, north of Kingston, into Rocky Hill, which forms the
other half of this belt, to its western end.

Almost in the prolongation of the Rocky Hill line of trap occur
the hills between Pennington and Woodville, and upon the Dela-
ware those called Smith’s Hill and Bellmont.

Northwest of Rocky Hill lies the nearly parallel range of the
Rock or Sourland Mountain, having the features of a broad
table land, rather than of a rugged dike of trap, its superficial
rocks being chiefly altered shales.

Nearly in a southwestern direction from the end of the Sour-
land Mountain, the trap, probably of the same belt, shows itself
near Rocktown, ranging hence to the Delaware, where it consti-
tutes the bold ridge known as Goat Hill.

Higher up the Delaware, above the mouth of the Alexsockin,
we find another shorter belt of trap, showing itself near the river.

The last principal outbursts of the rock towards the northwest,
are the Round Valley Mountain, and the dike or dikes which
traverse somewhat obscurely the elevated table land styled the
Swamp, and which are traceable from near Black’s Eddy for
several miles to the northeast. Several other narrower dikes
exist, some of which will be mentioned hereafter.

Composition and Structure of the Trap, and its Relation to the
other Rocks.

The ordinary aspect of the rock varies from that of a fine-
grained, compact basalt, to a coarsely crystallized greenstone
trap. It contains, in different localities, besides its more essential
components, hornblende, felspar, augite, and titaniferous oxide of
iron, various other minerals of more rare occurrence, such as
epidote, prehnite, zeolite, stilbite, analcime, and datholite.

The rock to which we have here given the generic name of
trap, consists in reality of several varieties, differing somewhat in
composition, the more important of which it may be proper to

144

describe. Its essential constituent is felspar, which is united in
some cases with hornblende. It then belongs to the class of rocks
denominated greenstones. In other instances the felspar is asso-
ciated with augite, a very common case along the Delaware;
and this mixture is a true dolerite rock. Again we find it con-
stituted of felspar, augite, and the titaniferous oxide of iron, a
composition which entitles it to the name of basalt. This basalt,
however, often contains hornblende, as we may behold in the
rock of Goat Hill. A fourth variety, of more rare occurrence in
New Jersey, is the kind called toadstone, an amygdaloidal trap
composed of a vesicular cement or paste, usually of fine-grained,
rather earthy basalt, embracing small spherical or ellipsoidal
cavities, occupied by extraneous minerals. A trap rock of this
character occurs in the ridge north of Scotch Plains.

The crystalline structure of these trappean rocks is no less
various than their composition, presenting every gradation, from
that of a homogeneous paste, in which all traces of a distinct
grain disappears, to a coarsely granular aspect, in which we may
plainly detect the several constituent minerals. The same ridge
or broad dike frequently shows all these shades of crystallization,
disclosing usually the more compact varieties near the out-
skirts of the belt, and the conspicuously granular kinds near
its centre.

The structure of the trap is usually that of a massive or amor-
phous rock, destitute of any greater regularity in its divisional
joints than such as occasion a prevalence of the cubical and
trapezoidal form in the blocks into which it separates. But in
some instances is displays an approach to the bedded structure,
as if, while in the melted state, layer had flowed over layer in a
nearly parallel arrangement. This may be seen at several
localities on the Delaware. In other cases, for instance at the |
Little Falls of the Passaic, we find it assuming the true basaltic
character, separating into regularly formed perpendicular pris-
matic columns. At the same locality the lower portion of the
mass of trap has the spheroidal structure, being a confused
assemblage of concentric nodules.

Almost every relation which igneous rocks ever.present to the
strata intersected by them, may be witnessed in these trappean
belts of the red sandstone region. But the usual modes of posi-

145

tion are, first, where the trap reposes unconformably upon the
secondary strata, as may be seen in a number of interesting
exposures; and, secondly, where it intersects or traverses the
strata in nearly vertical dikes, conceived, from the known volcanic
nature of the rock, to exist in every trappean ridge, but only
occasionally disclosed to observation.

That the trap is of posterior origin to the red sandstone forma-
tion which it overlies and intersects, is obvious, but at what pre-
cise epoch we are to suppose it to have been etruded to the
surface, and whether all its numerous outbursts were contempo-
raneous or occurred at successive periods, are points open to
discussion. After reviewing all the phenomena of igneons action
in the region, we shall touch upon these interesting questions.

Throughout the whole district where the trap abounds, we
notice instances of its superposition to the stratified shales and
sandstones through which it has burst its way to the surface.
Interesting proofs of this occur along the shore of the Hudson, at
the eastern base of the Palisadoes, where several varieties of the
sandstone are visible near the water’s side, dipping at a gentle
inclination westward and into the ridge. The same thing is well
displayed in the bed of the Passaic river below the Falls at
Paterson; the trap reposing over the westerly dipping beds of
the sandstone, and presenting some curious evidences of its
having reached this position while fluid and in a state of intense
ignition.

Of the Local Features of the Trap and the Alterations induced by
it on the Adjacent Strata.

I now proceed to a particular account of some of the more
striking features of these injected dikes, and of the modifications
they have produced in the contiguous stratified rocks. Many of
these changes in the texture, contents, aspect, and properties of
the neighbouring rocks, attributable to the intense heat originally
imparted by the intrusive trap, are of a kind familiarly noticed in
the vicinity of igneous veins and dikes; but there are some which
I shall have occasion to describe, that are of a less common cha-
racter, and which tend, by the views connected with them, to

13

146

corroborate some fundamental doctrines recently advanced by
geologists.

The first Newark mountain is an elevated range of trap, dis-
playing in many places south of Paterson, fine mural escarp-
ments of considerable height, especially along its eastern side.
The face of these cliffs is often remarkably smooth and regular.
Near Paterson, the trap rock is seen at the Falls of the Passaic
overlying the red sandstone, which displays near their contact a
modification of structure not unusual in such cases.

The interesting waterfall at this spot, seventy feet in height, is
caused by the dike of trap which crosses the river in the form of a
fine naturaldam. The entire mass of water precipitating itself over
the brink of this dam, passes first into a lateral cleft or chasm in
the dike, and thence descends into a deep pool or basin, which it
has excavated for itself in the subjacent softer sandstone. The
trap rock of the cliffs around, presents a strong tendency to the
columnar structure. Within a few yards above the level of the
river, beneath the Falls, we behold the junction of the igneous and
the sedimentary rocks. Between the true trap rock above and
the altered sandstone below, there occurs a mass, of five or six
feet thickness, possessing the structure of a toadstone or amygda-
loid, enclosing geodes filled with prehnite, analcime, zeolite, and
several other minerals. Immediately beneath this, we discover
a layer of the sandstone, a few inches in thickness, bearing all
the marks of partial fusion, being filled with small vesicular cavi-
ties, as if from the extrication of steam, and looking like an over-
baked mass of brick or pottery.

At a gorge in the same ridge, near Plainfield, the rock departs
somewhat from its ordinary aspect, being easily splintered, rather
metallic in its lustre, and containing frequent streaks or fine lines
of the red oxide of copper. Near another notch in the mountain,
a little north of Scotch Plains, a credulous miner seeking for the
precious metals, has disclosed an interesting mass of cellular or
amy gdaloidal trap, of a peculiar light yellowish-green colour. In
this neighbourhood minerals of the zeolite family are frequently
found.

While mentioning the thin seam of limestone in the narrow
valley of Greenbrook, between the first and second trap moun-
tains, a few miles north of Scotch Plains, reference has been

147

already made to the changes induced by the trap of this locality,
both upon the limestone and the red shale.

The next belt of the igneous rock towards the northeast worthy
of especial mention in this place, is that called the Second New-
ark Mountain. Where this ridge crosses the Passaic river, form-
ing the gorge of the Little Falls, the structure and relations of
the rock are finely developed. A little below the Falls, the trap is
seen in direct contact with the red sandstone, overlying it in a
mass from twenty-five to thirty feet in thickness, and presenting
a rather unusual appearance. The lower portion, about fifteen
feet in thickness, resting immediately on the stratified rock, is
an assemblage of irregular spheroidal ba ls of a somewhat con-
centric structure, traversed in all directions by small fissures or
joints; externally these are of a rather rusty hue from atmosphe-
ric action oxidizing the iron in the rock, but when broken they
show a dark, iron-gray colour, with a somewhat metalliferous
aspect. The material filling the interstitial portions between the
balls, is a dark-coloured, close-grained, very earthy basalt. It
sometimes includes crystalline quartz of various colours; among
others the amethystine and smoky varieties.

Above this confused mass of nodular concretions, the rock
assumes the true basaltic structure, exhibiting regular columnar
prisms, beautifully symmetrical, extending up to the superincum-
bent soil.

At this locality, the trap rock includes crystals of prehnite,
stilite, carbonate of lime, and other minerals.

Somerville Trap Ridge and Bridgewater Copper Mine.—The
next point on this first belt of trap at which we meet with any
phenomena of a specially instructive nature, is in the neighbour-
hood of Somerville, where the ridge has curved round to assume
a northwest course. In the various excavations of the old Bridge-
water copper mine, we have an opportunity of beholding the
acticn of the trap upon the rock into which it has been intruded.

At this mine we have ocular evidence that the igneous rock
issued through the strata through fissures of contracted width,
when compared with the base of the ridge which it constitutes.

A level extends from a shaft near the southern base of the
ridge in a north direction, towards the centre of the hill, or

148

beyond it, reaching upwards of seven hundred feet. The rock
which it chiefly traverses is the red shale, not much affected in
structure by the trap which overiies it in the hill, until we approach
very near the point of contact of the two materials. The refuse
matter at the mouth of the gallery of the mine itself, shows that
very little genuine trap was intersected in cutting this tunnel
across the strata.

The copper ore, which was the object sought, was found
chiefly adjacent to the slightly altered shale, or immediately
before it becomes excessively changed in structure, near its
contact with the trap. This interesting circumstance of the posi-
tion of the ore, which embraces principally the carbonate, red
oxide, and silicate of copper, is by no means confined to the
locality before us, but seems to prevail in relation to all the
explorations of any magnitude hitherto made for copper within
the State. The theory of the origin of these ores, suggested by
this and other facts, will be presented under another head, when
the copper mines have been specially described. The ore, as in
nearly every copper locality in the State, is connected with no
true gangue or vein stuff, implying a genuine metalliferous lode
or vein, but is diffused as if by sublimation through the altered
red shale, filling or lining its minutest fissures, and presenting,
therefore, a large surface of bright green ore to the eye, while
the metalliferous coating is in reality extremely thin.

Deeper in the hill, there occurs a more highly altered variety
of the red shale, but this is usually destitute of metatliferous matter.
In external aspect and structure it resembles somewhat the trap
rock, but its texture and composition show it to have been the
stratified shale changed by heat. Its fracture is conchoidal, very
nearly resembling that of the trap, and it has the same tendency
to form numerous spherical balls.

New Brunswick.—The next locality which deserves description,
belongs to a more eastern belt of trappean injections. This
ridge is one and a half miles west of New Brunswick, of gentle
elevation, composed principally of red shale, apparently under-
laid in part by trap rock. The shale has an altered colour, and
in some of the higher parts of the hill, the trap obtrudes itself at
the surface in loose fragments. At one point in the immediate

149

vicinity of the trap, there occurs a considerable quantity of the
sulphate of baryta, scattered in detached pieces over an area of
perhaps a fourth of an acre, which is nearly barren of vegetation.
Precisely the same circumstances exist in a locality of the same
mineral, in Bucks county, Pennsylvania; the sulphate of baryta
lying adjacent to the trap, and giving rise to a remarkably sterile
soil.

In some deep borings made at New Brunswick in search of
water, it is evident, from the description given of the materials
which were encountered, that more than one narrow dike or
perhaps bed of trap rock was met with, whose outcrop on the
surface has not been detected.*

Rocky Hill and its Prolongation.—The next trap belt, interesting
from the phenomena connected with it, is that of Rocky Hill.
Commencing at its eastern termination near Lawrence’s brook,
we observe the shale on both sides to assume, as we approach
the dike, a bluish colour, and an extremely compact structure:
On the southern declivity of the hill it is of a purplish or cho-
colate tint, and excessively hard and tough. It is studded
throughout with small spherical knots or crystalline nodules,
consisting apparently of the minerals epidote and hornblende, in
a state of incomplete crystallization. This belt of altered shale
extends from a point about half a mile southeast of the straight
turnpike to the Millstone river, which it crosses at the foot of
Rocky Hill, near Kingston. The changes induced in the whole
lithoid character and structure of the shale, by the intruded
igneous rock, are very finely exhibited along the canal, at both
the northern and southern bases of the Rocky Hill dike, evincing
a curious gradation in the crystalline action, as we approach the
trap.

Near the southern base of the ridge, the red argillaceous sand-
stone displays the series of changes already noticed, its colour
becoming deepened, and dark crystalline knots or kernels abound-

* I may here mention as adding another locality to the numerous ones already
observed, both in Europe and this country, showing the increase of the earth’s
temperature as we descend, that in one of these artesian wells, the water derived
from a depth of 175 feet being 52° Fahr., upon reaching a depth of 275 to 300 feet,
its temperature was 54° Fahr. This last is exactly the permanent temperature of a
fine natural spring, which issues from the side of a hill about a mile southeast of
the town.

13*

150

ing in it; we then come to the true trap, which at the river is
not wide. Immediately upon the northern side of the trap, the
sandstone rock re-appears with its usual dip to the northwest, but
presenting some remarkable modifications. ‘These may be seen
Opposite the toll-house, at the village of Rocky Hill, upon the
canal, in a quarry one hundred feet to the north of the trap rock.
The inclination of the strata being not more than 15°, the lower
beds in the quarry cannot be fifty feet remote from the subjacent
trap. They are filled to such a degree with various crystalline
matters, and show therefore so much inequality of composition
and hardness, as to be unfit for building stone. As we descend
in this quarry, the rock departs from its character of a sandstone,
though at a certain depth the change of texture is precisely that
which is desirable in a material ordinarily too easily acted on by
the weather. About one hundred feet from the trap, the rock has
the condition of a very close-grained, compact, and reddish, or
purplish sandstone, of a somewhat argillaceous texture, while it
is full of dark spheroidal kernels or nodules, of a radiated struc-
ture, of the dimensions of a pea or less. The nature of the
mineral is rather obscure, from the absence of all definite crys-
talline character. This stratum is a very durable rock, and is
extracted in regular masses, furnishing a building stone which is
in considerable request. In the middle of this stratum, there is a
thin bed, four feet wide, which seems originally to have. been a
sandstone containing much felspar. It is full of small irregular
cavities, the sides of which are studded with a black mineral,
crystallized in regular prisms. This is schorl, regularly and per-
fectly developed. Numerous fissures or joints in the rock are
occupied with the same black mineral, which is always highly
crystallized. The rock of this bed is rejected as a building stone.
Near the top of the thick stratum, of which this is but a narrow
layer, the rock acquires a less altered aspect, being redder, softer,
and having less of the jaspery texture, but containing kernels of
pure epidote, well developed. This variety extends from where
it first shows itself, which is from the trap, about one hundred
and fifty feet in the thickness of the stratum, to a distance of a
fourth of a mile, where it is well exposed, being excavated at
another quarry. It gradually and regularly acquires the ordinary
unaltered features of the red sandstone; but is even in the second

151

quarry remarkable for the distinctness and size of the green
spheroidal masses of epidote. The degree of baking which it
seems to have received even at this distance from the trap, has
given it a closeness of texture which fits it finely for purposes
requiring a durable building stone. Near the same quarry, the
rock contains a narrow band of nearly pure epidote, about an
inch and a half thick. Beyond this second quarry, towards
Griggstown, the rock soon assumes its usual soft slaty texture
and deep red colour.

The zone of altered shale, having the structure above described
at the Millstone river, extends particularly along the northern
flank and base of Rocky Hill, to its western termination, rising
high on the slope of the ridge, whose southern crest alone contains
the trap.

North of Princeton the southern belt of the altered rock lies in
a lower ridge, parallel with the ridge of trap, but separated a
little from it, the intervening depression having resulted from the
comparatively easy disintegration of the highly altered rock
lying directly in contact with the trap. When we trace this belt
of discoloured shale westward, we find it disappearing before we
quite reach the termination of the prominent portion of Rocky
Hill, whose actual termination is, however, much beyond the
point indicated on the map. It forms, in fact, a continuous
though irregular chain with the trap hills east of Herbertstown.

Near the head of Jacob’s creek, at the abrupt termination of
one of these trap hills, there is an old mine, where excavations to
some extent have been made in search of copper ore, the rubbish
discharged from the diggings, showing some traces of that metal.
_ The same series of nearly continuous dikes extends to the
Delaware, forming two conspicuous elevations near the river
called Smith’s Hill and Belle Mount. In this western portion of
the belt the trap has produced effects on the shale and sandstone
similar to those seen along Rocky Hill. Upon Moore’s creek
the strata are much altered, having a dark bluish or purple
colour, and being excessively indurated. Their nearly black
hue, when wet, has led to the notion that these shales are the
dark carbonaceous slates of a coal formation.

In the hill called Belle Mount the trap rock is well exposed,
having been excavated in making the feeder of the Raritan canal.

152

It possesses less of the basaltic character than belongs to much
of the trap in the Newark ranges. It is of a gray colour, rather
coarse texture, and consists of a large proportion of felspar,
united with augite, and is therefore a true dolerite or augitic trap.
Some portions contain hornblende instead of the augite, being in
these cases the rock called greenstone trap. These two varieties
are distinctive of nearly all the belts of this rock in this neigh-
bourhood, including the important one of Goat Hill.

Sourland Mountain.—The next zone of trap and altered rock
which claims our attention is that of the Sourland Mountain and
its prolongation, Goat Hill. This lies northwest of the belt just
described. Viewing the general topographical features of the
Sourland Mountain, and the wide plain of red shale and sand-
stone around its base, from any part of the Somerville trap ridge
distant several miles, we are led to some interesting reflections
regarding the small degree of violence which has accompanied
the protrusion of the trappean rocks of this region generally.
Standing on the large rubbish banks of the old Bridgewater
copper mine, where we are elevated scarcely one hundred feet
above the general surface of the wide level tract of red sandstone
spreading to the south, southwest, and west, we overlook the
country for a great distance, and behold the Sourland Hill rising
like a broad solitary island from the smooth surface of the
extended plain. The very features of the scene are enough to
indicate the absence of any great convulsive disturbance of the
strata during the outpouring of the trap, which seems to have
made its way to the surface through a series of long and narrow
fissures, produced by the mere gaping asunder of the rocks, and
not, as in some regions, by enormous vertical disruptions and
irregular uplifting movements, imparting invariably a broken or
undulating contour to the scene.

In the Sourland Mountain the trap rock is confined. chiefly to
its broad rounded summit, forming the axis of the hill; while,
from this position to beyond its base, reposes, on each side, in
undisturbed and regular stratification, a thick belt of the indurated
and baked shale. On the northwestern flank of the mountain,
towards Flaggtown, the rock in some places shows striking
evidence of the intensity of the igneous action, for it has all the
aspect of the fused slag or cinder of a furnace. Portions of it

153

are excessively hard and tough. At the base, near the northern
termination of the hill, the shale still manifests a great degree of
induration; it is of a blue colour and compact grain, but retains
its slaty structure sufficiently to fit it excellently for flagstones,
for which it is quarried. ‘The condition of things in and around
the Sourland Mountain is well seen by crossing it northward from
the little village of Hopewell, near its southeastern base. Imme-
diately north of Hopewell we pass over a ridge of little elevation,
at the base of which is a light gray arenaceous sandstone, easily
disintegrated, containing both the micaceous and brown oxides
of iron in considerable abundance. The summit and northern
declivity of this low ridge consist of blue shales somewhat indu-
rated. Crossing a narrow valley to the southeastern foot of the
main Sourland Mountain, we find its entire slope composed of
the shale in a highly altered state, being blue, compact, and
greatly indurated. It is excessively tough, difficult to fracture,
and produces a clear ringing sound when struck. The loose
masses often exhibit externally a peculiar glazed aspect, analo-
gous to that upon the surface of some kinds of slag. These
altered strata extend to the highest parts of the mountain.
Crossing a slightly depressed belt, the trap rock next displays
itself, and continues to the northwestern declivity, where it gives
place again to the altered rocks composing the other flank. The
whole mountain is thus formed of a series of nearly parallel
elevations, with more or less considerable intervening depres-
sions, or valleys, which are by no means regular, the single
axis of trap rock occupying a nearly central position.

In the southwest prolongation nearly of the Sourland Mountain
we find the same or rather another almost continuous and parallel
dike, which passes a little south of Rocktown, and thence to the
Delaware, making there the axis of Goat Hill. This elevation
ranges about half a mile southeast of Lambertsville, and crosses the
Delaware in an oblique direction, appearing on the Pennsylvania
side below New Hope, where it displays some interesting pheno-
mena. Along the northwestern base of this ridge, on both sides
of the river, the strata dip as usual, but are affected in a striking
manner in their structure and composition for at least a fourth of
a mile from the trap. In the quarry northeast of Lambertsville,
we discover the commencement of the change. There the red

154

sandstone, varying but little from its ordinary colour and being
only rather more compact, contains a multitude of the large
spheroidal nodules of pure green epzdote, many of which are at
least an inch in diameter. ‘They seem not to be distributed pro-
miscuously through the rock, but to be arranged somewhat in
layers, parallel to the planes of the strata, though they are often
several inches asunder. Two or three hundred feet nearer to
the trap, we find the rock darker and harder, and the number of
nodules greatly augmented, though they are generally of much
smaller size. The common colour of the reck is here a very
dull purplish blue, and that of the included nodules a dull black
or a deep blue. They are of all sizes, from minute specks to the
dimensions of a large hazle-nut, and possess every shade of
distinctness contrasted with the material enclosing them. They
seem to consist of some imperfectly formed mineral, apparently
tourmaline in a semi-crystalline state. ‘These spherical nodules
or specks, are oftentimes surrounded by a crust or coating of
another material, usually nearly white; and I have remarked that
the more obviously formed this crust appears, the more crystal-
line or fully developed is the interior kernel, which, at this spot,
seems to approximate in its features to black schorl or tourma-
line. A few hundred feet nearer to the trap, or almost at its
base, the rock presents a still different aspect, being of a dark
gray hue, and somewhat coarse-grained. It seems to have been
a sandstone, containing little or no clay, as it has nothing at all of
the baked jaspery texture of that previously described, which has
plainly been either a shale or a very argillaceous sandstone. This
gray rock is speckled with innumerable small crystals of very
regularly formed tourmalines, some of which are more than half
an inch in diameter. Upon the opposite side of the river, below
New Hope, we meet with very nearly the same order of things,
except that the rock containing the completely formed tourma-
lines is absent.

In one thin layer of the altered red argillaceous rock on the
Pennsylvania side, the mass, which is of a pink hue, contains,
blended with the crystallized epidote, some minute but perfectly
formed crystals of a mineral, apparently idocrase, of a beautiful
Wine colour.

The altered belt here described, ranges northeastward from

155

the river for several miles, being continuous, in fact, with that
already spoken of, which forms the northwestern flank and base
of the Sourland Mountain. About a mile southeast of Mount
Airy, the blue and purple shale contains an abundance of epidote
in oblate spheroidal concretions of very regular shape. The
average breadth of the belt is very considerable, amounting at
least to a quarter of a mile.

West of Ringoes the shale in some places exhibits a considera-
ble degree of change from its proximity to a bold dike of trap,
which shows itself in a hill above the mouth of the Alexsockin
creek. In crystalline structure this trap departs even more
widely from the fine-grained basaltic variety seen in the hills
near the Passaic, than does that of Goat Hill and Belle Mount,
lower down the Delaware. It is coarsely granular and crystal-
line, consisting chiefly of a yellowish-white felspar, traversed by
bladed or elongated tabular crystals of green hornblende of con-
siderable size. Much of this rock bears indeed a closer resem-
blance to some varieties of sienite than to ordinary trap rock,
exhibiting the justness of that generalization which makes the
trappean family of rocks to include those sienites which are
composed of the two minerals, felspar and hornblende. Between
this belt of trap and the Alexsockin creek we find a disturbance
in the direction of the dip, being the only irregularity of this kind
of any magnitude in the whole red sandstone region, which is
referable to the protrusive action of the igneous rock. On the
southeastern side of the dike the strata of shale and sandstone
are in some places much contorted and broken, but their prevail-
ing dip is towards the southeast, or directly opposite to the usual
quarter. This contrary order of the dip throughout the district
along the Raritan and its north branch, I attribute to the pecu-
liar direction taken by the currents which precipitated these
sediments in this portion of the basin, and not to any upheaving
force.

1 have already when describing the several zones of the red
shale and sandstone formation along the Delaware, mentioned
the altered aspect of the strata over the wide tract called the
“ Swamp,” the general limits of which were at the same time
defined. With the exception of some occasional exhibitions of the
trap rock, particularly in the vicinity of the southeastern margin

156

of that table land, the only material generally visible upon its
surface, is the highly indurated and altered shale; the igneous
matter itself having apparently in but few instances reached the
day. Along the Delaware, however, about two miles above the
mouth of the Lockatong, and nearly opposite the mouth of the
Tohickon, near Black’s Eddy, the trap appears on both sides
of the river in a somewhat massive dike. On neither side of
the Delaware does the trap appear at the surface on the top
of the ridge or table land; and would never have been exposed,
but for the denudation which excavated the deep channel through
the rocks, by which the river now flows. The existence of the
trap rock under these circumstances, lends confirmation to the
opinion already implied, that the induration of the strata in many
of the broad belts described, is the result in part of the heat pro-
pagated from masses of igneous rock which have never reached
the surface.

Regarding this conclusion as almost demonstrable from the
phenomena, does not analogy furnish us ground for the interest-
ing doctrine, which attributes the crystalline structure of gneiss
and other stratified rocks of the primary class, to the modifying
influence of subjacent bodies of granitic, and other igneous matter
intensely heated, acting upon sandstones, slates, and similar sedi-
mentary strata ?

Reviewing the several facts presented in the previous descrip-
tion of the principal belts of altered shale and sandstone, we find
many of them of a kind calculated to add weight to this hypo-
thesis.

In the great thickness of the zone of strata throughout which
such remarkable changes have been induced in the texture, and
evén the molecular structure of the rock, by the heated trap, we
have evidence of the magnitude of that cause, which when exerted
in far greater intensity and universality upon the sedimentary
deposits of the earlier periods of our planet, may have been fully
adequate to produce that more entire change to general crystalli-
zation, which the metamorphic theory assumes. A curious and
important proof that the modifications in the strata described,
have resulted wholly from the high temperature of the molten
trap, is to be found in the circumstance that all the indications
of alteration or an approach to a semifusion of the mass, augment

157

regularly as we approach the dike. The crystalline nuclei, first
extremely minute and faintly marked, become progressively
larger and better defined, assuming when within a certain,
though still considerable distance, all the characters of a fully
developed mineral, possessing in some instances the structure
of a perfectly regular isolated crystal. As this gradual segrega-
tion of certain specific mineral combinations increases, we notice
a progressive obliteration of all the ordinary features of the
rock.

Another highly interesting point is the intimate connexion, che-
mically, in every instance, between the composition of the stra-
tum acted on, and the species of mineral secreted. Thus in all
the principal localities of the epidote, we find the red shale con-
taining by analysis all the constituents essential to that mineral,
even the lime. Moreover, the red sandstone, so usually destitute of
lime, is singularly enough the stratum in which the tourmaline, a
mineral not holding any lime, abounds.

Where the rock has been a calcareous and very argillaceous
red shale, the mineral produced has invariably been epidote, the
ingredients of which are silica, alumina, lime, oxide of iron, and
a little manganese, the five prevailing constituents of the red shale.
On the other hand, where the rock has been originally a some-
what more arenaceous compound, such as usually goes by the
name of argillaceous red sandstone, a triple mixture of alumina,
silica, and peroxide of iron, there we find, in place of epidote,
a profusion of black tourmalines, the composition of which,
as analyzed by Kloproth, is 40 alumina, 35 silica, and 22 oxide
of iron.

There are several other imperfectly crystalline minerals some-
times associated with the above, but I have not yet found time
to investigate their composition and probable origin.

A careful examination of the altered rocks near the trap would,
I doubt not, result in much useful information of a strictly prac-
tical kind, in reference especially to a right selection of stone for
purposes of architecture. I conceive that the very best varieties
of building rock in this region of the State, will be found in the
indurated strata, contiguous to the ridges of trap, where the baking
process has obliterated the slaty cleavage, and destroyed that
soft friable texture which usually renders so large a portion of

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158

the red sandstone of the district of no value. As this section of
the country is not well supplied with building stone capable
of withstanding the weather, the hint that durable varieties
abound near the trap ridges, may prove of service. From what
has been said, it will be seen that the most probable position for
the better kinds, is neither too near the trap nor too remote from
it, but is indicated by the amount of baking, which the rock ap-
pears to have undergone. This should not be too great, lest the
rock be very hard and difficult to cleave into regular blocks;
nor yet too little, as it will be then soft enough to be operated on by
the frost. When a rather compact and extremely durable kind
is sought, I would suggest that it will usually occur within one
or two hundred feet of the trap, and may be known by a bluish
or dull purple colour, and by a multitude of dim round spots, the
commencement, as it were, of the crystalline nodules. On the
other hand; when a rock of rather softer variety, but cleaveable
into larger blocks, is desired, then I would propose the beds rather
more remote from the trap, where the stone retains a pretty
bright red colour, and contains large, fully formed nodules of
green epidote.

It is not asserted that these altered strata will always appear
bordering the ridges of trap; but I find them in frequency far
greater than might be expected, and their importance therefore,
is considerable. By following the base of a range of trap, though
we may not at once meet with any rock of that exact degree of
induration which we seek, we cannot pursue the search far in
the longitudinal direction without falling upon a locality where
all the requisite varieties present themselves. Much aid will be
derived from inspecting the spots and nodules upon the fragments
scattered over the surface of the soil.

OF THE COPPER ORES OF THE RED SANDSTONE REGION.

The ores of copper, especially the carbonate, red oxide, and
blue sulphuret, exist in many places in the red sandstone region,
though hitherto they have never been procured in abundance.
Their position in every case would appear to be contiguous to
dikes of trap; the present seems therefore the appropriate place
in which to describe them.

159

The particular manner in which these ores occur, gives to the
inquiry concerning them, some degree of interest both as respects
the question of their origin, and the probability or not of a lucra-
tive return for the expense of mining them. Several vigorous
and persevering attempts have been made at successive times,
to open mines of copper in this region, but invariably without
success; and it becomes an important point to trace, if practi-
cable, the cause of the general failure, and to ascertain in fact,
whether it is not mainly referable to an actual deficiency in the
amount of ore, and to its diflused state through the rock. As
it is desirable that the information collected should have a prac-
tical and salutary bearing upon future mining enterprises in the
district, much capital having been already absurdly wasted, I shall
submit such details as have been collected, believing that the
conclusions they suggest, if not positively demonstrable, are
highly probable.

The principal points where mining operations have been under-
taken at different times, are near Belleville, Griggstown, Bruns-
wick, Woodbridge, Greenbrook, Somerville, and Flemington.
For details concerning the early history of the mines at Bruns-
wick, Belleville, and Somerville, I refer the reader to Gordon’s
Gazetteer of the State; at the same time expressing my belief,
that far too favourable an impression is conveyed in that work
of the metallic riches of those localities. With the exception of
the Flemington Mine, which has lately been worked to some ex-
tent, and which is a more recent enterprise, these several works
are all at present in such a state of decay, as to make it impossi-
ble to ascertain by direct inspection, the mode in which the ore
occurs. My information upon this head, has been derived from
examining the masses of ore and rubbish near the mines, and
especially from the testimony of persons familiar with the works
while they were in operation. Every thing that I have witnessed
or collected in regard to it, has led me to the opinion, that the ore
does not exist, in any instance, in the shape of a true vein; in
fact, we have no evidence that a regular copper vein, properly so
called, has hitherto been met with any where in the formations
of the State.

By a true vein is meant “the mineral contents of a vertical

160

or inclined fissure nearly straight, and of indefinite length and
depth.” Such veins have usually a well-defined line or plane of
separation between their contents and the rock on each side,
which is named the wall of the vein. Now the chief peculiarity
in the copper ores of the region before us is, that they occur, not
in regular sheets of mixed metalliferous and mineral matter tra-
versing the rock, but in irregularly ramifying and intersecting
strings and bunches, in which the masses of ore are not mingled
with the usual foreign materials of metallic veins, but blended
with the adjacent red sandstone or shale, which is in a more or
less altered state. The nature of these accumulations of metalli-
ferous matter will be best understood, however, from a descrip-
tion of the position of the ere at two or three of the principal
mines.

In the Schuyler Mine, near Belleville, in Essex, the principal
body of the ore is stated to be imbedded in a stratum of sand-
stone, twenty or thirty feet in thickness, and to dip about 12° from
the horizon, rather by steps than regularly. It has been worked
two hundred and twelve feet below the surface, and one hundred
and fifty feet horizontally from the shaft. The chief ores are
sulphuret and carbonate of copper, and they occur almost inva-
riably blended with portions of the indurated red sandstone.
Judging from the latter fact and the gentle dip of the mass, which
appears to be about that of the neighbouring strata, it is pretty
obvious that it has but little claim to the character of a true vein,
though it is not asserted that the quantity of ore in this mine may
not be considerable. It would seem as if a particular band of the
rock had been injected with the metalliferous matter, not filling a
cleft or fissure, but dispersed and as it were dissipated by subli-
mation through the substance of the sandstone. There is no trap
exposed on the surface any where in the immediate district of the
Schuyler Mine.

At the Falls of the Passaic, near Paterson, traces of copper, in
the form chiefly of the green carbonate, occur near the foot of the
high cliff of trap rock, on the north side of the river, immediately
at the base of the Falls. A fruitless excavation was formerly
made at this spot, in quest of a regular vein. Huge perpendicu-
lar rents or chasms divide the trap, of unknown depth, and in a

161

direction nearly coincident with that of the ridge. It is into one
of these great clefts that the waters of the Passaic precipitate
themselves at the Falls.

In the red sandstone between East and West Bloomfield, green
carbonate of copper is occasionally seen, but always in the form
of a very thin film or crust, filling the minute seams and divi-
sional joints of the rock, and never but in very inconsiderable
quantity.

At several points in the neighbourhood of New Brunswick, ores
of copper have been found; and prior to the revolutionary war,
an extensive and costly attempt was made to establish a mine
here, but without success. The red shale is in many places coated
by the blue and green carbonates of the metal, in the form nearly
of a thin pellicle. In a few instances the metal occurs in the pure
state, soft and malleable, in the shape of a thin plate, injected
into the body of the rock, rarely more than the twentieth of an
inch in thickness. In every such case, the contiguous rock is
more or less indurated, as if by heat; and in immediate contact
with the vein of metal, its ordinary brownish-red colour is
changed to a light-gray for the thickness of a third of an inch or so.

The Franklin Copper Mine, near Griggstown, in Somerset
county, is ‘situated on the western declivity of a hill, whose sum-
mit is occupied by trap rock, but up the side of which the shale
rises to a considerable height. It is in this shale, which is consi-
derably altered by the trap, that the copper ore has been found.
The mine is in a dilapidated condition, and no longer accessible.
Judging from the character of the materials brought out from the
mine, and from the testimony of those who were familiar with it
when open, the excavation runs for some distance horizontally
through an altered shale of a dark purple colour, which becomes
afterwards paler and more siliceous. The ore occurs diffused
through this altered shale. Occasionally it has the aspect of existing
in very narrow short strings, or little veins of injection, being in
such cases mixed with carbonate of lime, felspar, hornblende, and
other minerals, constituting what approximates to a true metalli-
ferous gangue. The best ore found here is a soft blue sulphuret,
associated always with carbonate of lime; but the principal
species is the usual carbonate of copper and the red oxide, min-
gled through the altered shale, which abounds in little geodes or

14*

162

crystalline nodules of epidote and black tourmaline, sometimes
beautifully crystallized. The principal shaft is said to have been
one hundred feet deep; and the mine was drained by a long adit
which commences near the base of the hill, not far from the
canal. A considerable sum has been expended without success,
in opening this mine.

Interpreting all the appearances connected with the nature and
the mode of distribution of the ore, it would seem to be so diffused
throughout the altered shale, as to preclude its being ever profit-
ably wrought.

At the base of the trap ridge north of Somerville, occurs the
Bridgewater Copper Mine, once worked to some extent, but with
a serious waste of capital. Several facts respecting the position
of the ore in the midst of the altered shale, at some little distance
from the dike of trap, have been already mentioned. It was found
here principally in the moderately altered rock, near to which it
is excessively baked by proximity to the igneous rock. The ore
is pronounced to have been very rich, consisting of a considerable
proportion of massive red oxide of copper. There was also
found some native copper. The chief variety of ore, however,
was the usual green carbonate, mingled occasionally with green
phosphate, and some of the green silicate of copper.

This mine has been for a number of years closed up. Judging
from the character of the rubbish outside of the mine, which
gives a tolerably correct conception of the mode in which the
ore occurs, we infer that it is here accompanied by very little
true gangue or vein stuff, being sometimes in the form of thin
partial injections, but much more frequently existing in a dis-
seminated state among the altered shale and sandstone.

The Flemington Copper Mine, the only one recently wrought
to any extent, being open to inspection, gives an opportunity of
ascertaining accurately the usual mode of position of the ore.
In this mine the appearances are almost conclusive, as regards
the absence of a true vein, and corroborate strongly the opinion
already advanced, that the chief portion of the ore has pene-
trated the minute crevices of the impregnated rock, rather by
a species of sublimation, than by intrusion or injection in the
fluid state.

There seems to be a belt of metalliferous rock of very variable

163

breadth, sometimes twenty or thirty feet wide, which preserves a
nearly north and south direction for several hundred feet. What
the total length of this may be no one pretends to know, but two
miles due south from where it is exposed in the present Flemington
Mine, there are strong indications of a belt of precisely similar
character. In the Flemington Mine, the ore, which is a mixture
chiefly of gray sulphate and carbonate of copper, exists intimately
blended or incorporated with the semi-indurated and altered
sandstone, and parts of the mass have therefore somewhat the
aspect of a conglomerate of re-cemented fragments, the me-
talliferous part acting as the cement. ‘Though usually minutely
disseminated, it occurs occasionally in lumps of great purity and
considerable size. The line of rock containing the ore has no
definite separation from the unaltered red shale outside of it, and
it is therefore not always easy to judge of the precise space
which it occupies. The ore in this mine is of good quality, and
so far as I have been able to ascertain, the dimensions of the
band containing it, are such as to admit of the existence of a
large mine here, should the proportion of metallic matter in the
rock prove profitable. The mine seems to have been very judi-
ciously worked; cuttings being made across the ore in a series of
east and west alleys to ascertain its extent and position. But
while mining is of all arts the most precarious, it is especially so
where the metalliferous deposit does not occur under the shape of
a regular or true vein or lode. The doubts which some entertain
regarding the final success of this and other copper mines in the
State, proceed chiefly from the views entertained regarding the
manner in which the copper ore is diffused.

The Nechanic Mine lies apparently on the metalliferous belt of
rock above spoken of. The ore occurs under circumstances very
similar to those at the Flemington Mine. It is not at present
productive.

From the excellent quality of the ore of this belt, it is to be
regretted that a regular vein of some extent cannot be discovered,
the disseminated condition in which the ore exists, rendering all
mining operations very expensive, and limiting the supply of ore.
These mines are all near a narrow dike of trap of scarcely per-
ceptible elevation, which runs southward from the main ridge of
trap and altered rock, northwest of Flemington, and extends a

164

considerable distance to the south. The adjacent strata are in
most places considerably altered, and in some spots coated with
flakes of the green carbonate of copper.

Recurring to what we have adduced respecting the copper
ores of the State, it will be seen that they do not occur under
circumstances to make the adventurous miner sanguine in pur-
suing to a costly issue, the indications of this metal which so
frequently meet us throughout the red sandstone region. Nume-
rous cases exist in other countries, it is true, where rich mines
have been wrought in masses of ore that were not genuine
veins, nevertheless, when the deposites are like those common in
the copper region of New Jersey, mining becomes peculiarly
precarious. I have been thus explicit upon this subject, from a
persuasion, that one main advantage to be anticipated from a
rightly conducted geological survey, is the aid which it is capable
of affording to enterprise, by stimulating every branch of whole-
some industry, and checking rash and visionary undertakings. It
should furnish a faithful statement of what every district possesses,
and when necessary of what it does not possess. The one is as
needful as the other, if our motive be to give the industry of the
community a right direction. It may depress, and it cannot
strengthen the spirit of useful enterprise, to permit capital to be
misapplied to purposes that, when pursued, lead to loss and dis-
appointment.

When we contemplate the singular degree of uniformity which
attends the copper ores of the State, their strict resemblance in
point of composition, and the zdentity of the geological relations
under which they are found, we are strongly impressed with the
persuasion, that they all owe their production to one epoch, and
to one generally-operating cause. Finding them in almost every
case adjacent to igneous dikes, but not in contact with them, we
are led at once to the inference that they entered the crevices of
the somewhat crushed shales at the time of the outpouring of the
molten trap, and that hence, like it, their presence at the surface is
the consequence of an intense heat. The remarkable manner in
which the carbonate of copper is diffused among the minutest
fissures of the shale, its great re/ative abundance, and the well
known property of its ready sublimation, together with the curious
circumstance that both it and the other ores are rarely in im-

165

mediate contiguity to the trap, but among the moderately altered
less heated rocks at a little distance, all go to indicate that a con-
siderable proportion at least of the metalliferous matter, especially
the carbonate, entered the strata in a gaseous or volatile condition,
and not that of igneous fusion. This latter was more probably
the state in which the metallic copper, such as occurs near New
Brunswick, and perhaps some of the less volatile ores of the mine
at Griggstown, were injected.

In reference to the above speculation, it should be recollected
that the mass of the trap rock itself is not unfrequently seen to
contain both metallic copper, and its ores.

ECONOMIC GEOLOGY OF THE RED SANDSTONE REGION.

Several subjects have been already discussed, which from their
obviously practical importance, are entitled to a place in the eco-
nomic geology of the red sandstone region, but it was deemed
more expedient to introduce them in immediate connection with
the descriptive details which respectively suggested them.

Thus, in the general description given of the several members
of the red shale and sandstone formation, mention was made in
every instance of the degree of adaption to useful purposes, such
as those of architecture, statuary, paving, &c. of each particular
belt of rock examined. A similar allusion was also made to the
uses of the calcareous conglomerate, its fitness for burning into
lime and for cutting as an ornamental marble being both alluded
to. Care was taken to point out the precise position and dimen-
sions of any thin beds of limestone found interstratified with the
red shale or sandstone, and suggestions offered concerning the
most suitable situations in which to seek for good and durable
building materials among the altered rocks contiguous to the belts
of trap. In like manner, in treating of the copper ores of the
formation, whatever was of a practical bearing was fully con-
sidered.

I proceed to mention one or two other subjects of a somewhat
desultory nature, not yet adverted to, which appear to come
appropriately under this head.

Peat.—In the meadows and low boggy grounds about Spring-
field, and also near Connecticut Farms, occur large quantities of

166

excellent peat or turf. Itis rather extensively dug, and employed
in the neighbourhood as fuel. According to the statement given,
a cord of it properly prepared is as productive of heat as a cord
of good oak wood. The mode of preparing it is, to cut it into
regular quadrangular masses about two feet in length, with a
base four or five inches square. These pieces are carefully dried
and sold by the cord like wood.

Back water on the Passaic, caused by the trap dike at the Little
Falls—The Passaic and Pompton rivers, for many miles above
the Little Falls, are sluggish and half stagnant streams bordered
in most places by extensive meadows and marshes, which are
subject to frequent inundations, deemed prejudicial to the health
of the neighbouring country. This want of current is manifestly
produced by the bold dike of trap rock which intercepts the
stream at the Little Falls, forming a sort of natural dam, that
backs the water for a great distance along the level country
above. The mere removal of this dam of rock from the bed of
the river, to a depth of twenty or thirty feet, and over a width
sufficient to prevent inundation in times of high water, would be
a measure extremely beneficial to a large district bordering on
the two streams. A great extent of level meadow land along
the Passaic, at present too wet to be productive, would be
rendered dry and arable, and might become, when under the
plough, some of the best grain land of the State. Such a step
would, moreover, ameliorate the quality of the water in the wells
of the district, materially benefit the roads, and, a consideration
far above all others, it would improve the health of the inhabitants,
The expense would be in the removal of the obstruction, and in
the compensation to the owners of the water-power which would
be destroyed, but its entire amount would fall far short of the
great gain to the community, which many conceive would result
from the undertaking.

GENERAL VIEW OF THE CIRCUMSTANCES UNDER WHICH THE MIDDLE
SECONDARY ROCKS WERE DEPOSITED.

In the general description of the middle secondary system of
strata presented in the beginning of this chapter, the notion was
advanced, that these materials were deposited by an extensive

167

ancient river, having its source in the southern States, and its es-
tuary in the region of the Raritan and the Hudson, and having its
course for the most part southeast of the chain of the Blue Ridge
and the Highlands. Several important facts connected with this
trough, such as its present configuration, the uniform dip and
direction of its slightly inclined beds, implying a steady current,
their singular constancy of character, so indicative of one general
source for the whole, and the obvious identity of their materials
with the soils now furnished by the ancient rocks from whence
we would derive these deposites, all go to confirm the above
supposition.

When the details of the geological surveys of Pennsylvania,
Maryland, and Virginia, now approaching to completion, shall
have been united with the delineations herein given of this inte-
resting group of rocks, the long and narrow tract which they
occupy, will be seen to possess in a striking degree the features
of a noble river, taking its rise in the primary region of the
-southern States, and meeting the ocean, probably, at and eeyene
the outlets of the Raritan and the Hudson.

The traveller passing along the red sandstone belt from the
Hudson to the northern confines of North Carolina, will, if his
mind be directed to these considerations, become early impressed
with the accordant nature of the evidence which accumulates as
he advances. In commencing his journey, he will see the whole
formation, occurring in part still beneath in part above the present
level of the ocean. Passing the Raritan, where, for a certain
distance, the tide washes a portion of it, he will next find it on
the Delaware, elevated above the ocean level throughout its
entire width from Trenton to Durham. Advancing to the
Schuylkill between Norristown and Reading, he will observe its
height above the tide to have augmented ; and crossing thence in
succession the Susquehanna, the Potomac, and the James rivers,
he will perceive the tract still gradually and uniformly to ascend,
until it attains a level of several hundred feet above the sea,
marking an inclination nearly corresponding to that which belongs
to many of our large rivers now descending from the Appala-
chian chain into the ocean.

The progressive diminution in the breadth of the formation
is strictly in accordance with these facts. At the Delaware,

168

adjacent to the presumed ancient estuary or mouth of this sup-
posed stream, the width of the deposit amounts to thirty miles;
at the Susquehanna to about twelve; at the Potomac to be-
tween six and eight, and at the James river to not more than
four miles.

It may be objected to the argument above advanced touching
the regular and gentle ascent of the formation towards the south-
west, that the existing slopes of the whole district southeast of
the mountains may have been produced during the elevation of
the greensand and tertiary strata, at periods subsequent to that
which witnessed the drainage of the red sandstone valley.

Did the scope of the present treatise authorize the detailed
discussion of this curious point, we think that a comprehensive
investigation of the existing levels of the respective tracts, or, in
other words, the relief above the ocean of the several parallel
belts of country conceived to have successively emerged from
beneath the sea, would go far to convince us that the channel
which received the red shale deposits, possessed to a considerable.
degree, at least its present gentle slope towards the northeast,
during the epoch of its formation, which was apparently soon
after the cessation of those disturbances which finally elevated
the coal.

Let it be observed that the Kittatinny Valley, formed of rocks
uplifted at the close of the older secondary or Appalachian
epoch, has the same regular and gradual declension in level from
the interior of Virginia to the Hudson which we find in the red
sandstone belt of the parallel valley southeast of it. From an
elevation in the vicinity of the New River, approaching one
thousand feet above the level of the sea, it slowly descends
northeastward, until, at the Hudson, its general surface rises not
more than one hundred feet above the tide. While this is true of
the plains occupied by the older and middle secondary rocks, no
such variation in the level of the more recently lifted tertiary
plain along the sea-board is discernible. From the Roanoke to
the Delaware the tide every where penetrates this latter, and its
surface in that distance does not descend probably more than
one hundred feet. It seems, therefore, altogether improbable
that the whole of the northeastward descent in the first two
valleys, that northwest and that southeast of the Blue Ridge

169

chain, should have been acquired at the time of the elevation of
the tertiary, or at any period later than that of the final drainage
of the middle secondary trough. The disturbances of level which
took place at the close of the newer secondary or greensand period
are still further in favour of the same conclusion; for, while the
strata of that date were raised to a moderate height, averaging
sixty or eighty feet above the ocean in the latitude of New
Jersey, they underwent no permanent elevation above the tide
in the region further to the southwest, between the Chesapeake
and the Roanoke.

That the almost universal inclination of the planes of depo-
sition in the red shale and sandstone formation is the result of
the oblique or slanting mode in which the sediment has been
laid down by a rapid and steady current, and is not due to any
upheaving action, admits, I conceive, of very little doubt. If it
were a consequence of the latter cause, the vast width of the
region in New Jersey over which this northwest dip prevails
would imply a thickness for the deposit so enormous as to be
beyond all precedent among stratified formations. But we have
conclusive evidence of the comparative shallowness of this group
of beds, in the fact, that, in several localities, even in the interior
of the belt, it has been washed off in patches by denudation, so
as to expose the subjacent Appalachian limestone, which appears
in these places to have been the original floor of the basin. The
denudation along the southeastern border of the tract has, in like
manner, in many neighbourhoods, cut away the coarse sandstone
and conglomerate beds—the first deposited, and undermost, by
order of dip—making the now undermost layers to consist of the
red shales. This could obviously not occur if the materials had
been precipitated in a nearly level position, as in that case they
would have spread themselves along the bottom of the trough too
far to the northwest to be removed by local denudation along its
southeastern margin.

The very general dip of the strata towards the northwest and
north seems plainly to imply the side from which the sedimentary
matter chiefly entered this valley. That the lateral influx was
principally from the belt of country immediately bordering the
basin upon the southeast there can be little doubt; and we have
only to observe the nature of the rocks skirting that side of the

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170

belt in a broad tract, the whole length from the Susquehanna to
North Carolina, to find at once the red soil of which these strata
consist. Throughout this distance, talcose, chloritic, and horn-
blendic rocks compose nearly the entire zone of country lying
immediately southeast of the red shale; and the red soil which
they produce is so identical in aspect and composition with the
shales, and is at the same time so copiously furnished by their
disintegration, as to point plainly to these primary strata as the
source of most of the matter of this middle secondary trough.
If we conceive the northwestern side of the valley next the base
of the hills to have been, as it probably was, the deepest portion,
and the red ferruginous materials to have entered this large river
from the neighbouring talcose rocks, by currents setting obliquely
across and down the channel, we may at once explain, not only
the origin of these beds but their inclined position, and their pre-
dominant northwestern and northern dip.

In attempting thus to account for the prevailing dip of the red
shale and sandstone strata, ] am aware of the local exception to
be found in the southeastern inclination of the beds between
Middlebrook and Pepack, and its seeming incompatibility with the
above views. I would direct the reader’s attention, however, to
the peculiar position of the Mine Mountain, jutting out into the
estuary of the red shale, considerably to the southeast of the
general line of coast. It is easy to conceive that its influence
must have been to intercept the regular northward current, and
to deflect it over a certain area into a species of eddy, in which
the sedimentary matter would of course assume an unusual
direction in its gently inclined surfaces of deposition. Proceeding
east from the Round Valley Mountain, we find the dip at the
White Horse to be nearly northeast, then east, and near the mouth
of the Lamington river, southeast, and beyond Somerville, nearly
south, affording an almost convincing proof that such an eddy
prevailed, and presenting ample evidence, if such were wanting,
that the inclined posture of the strata is not the result of an
elevatory action.

Respecting the variegated calcareous conglomerates which
overlie the red sandstone formation, but little difficulty exists in
explaining both their source and the nature of the circumstances
which accompanied their production. The fragmentary materials

171

of which they consist, can be traced in every instance to the older
rocks of the neighbouring hills immediately bordering the middle
secondary plain upon the northwest; and we can discover a
relation between the amount of the several kinds of pebbles, and
that of particular sorts of easily abraded strata along the flanks
of the valley. Thus, in every case where calcareous pebbles and
a calcareous cement are abundant in the conglomerate, the older
secondary limestone (Formation II.) may be seen at the base of
the adjacent hills, and usually at an elevation that indicates it
to have been sufficiently above the waves to undergo extensive
destruction from a sudden and powerful rush of waters.

In order to account for such a violent denudation along the
base of the Highlands, we have only to advert to the state of
things attendant upon the outbursting of the trap. This rock,
intersecting and overlying equally all portions of the red sand-
stone, both its earliest and latest formed beds, was manifestly of
simultaneous date throughout the entire region. The violent
agitation of the whole belt of country, and the vertical rising of
the bed of the red shale valley to a higher leve!, would necessarily
set into rapid motion the entire body of its waters. These, rush-
ing impetuously along the shattered strata at the base of the hills
confining the current on the northwest, would quickly roll their
fragments into that confused mass of coarse heterogeneous pebbles
which we see, and strew them in the detached beds of conglo-
merate which they now form. The protrusion of the trap, the
formation and deposition of the conglomerate, and the elevation
and final drainage of the whole red sandstone basin, have hardly
been consecutive phenomena, so nearly simultaneous appear to
have been these events. The whole time occupied by these
stupendous changes must have been extremely brief, compared
with the period which produced the main mass of the materials
of the basin—the red shales and sandstones—which occupy so

large a part of it.
Of the Middle Secondary Rocks of the Green Pond and Long
Pond Mountains.

When describing the older secondary rocks of the long, straight,
and narrow valley which separates the two principal ranges of

172

the primary strata of the Highlands, it was stated that those
formations where they appear in the neighbourhood of Green
Pond and Macapin Pond, were overlaid unconformably by a
group of much newer date, conceived to have been produced in
the middle secondary period. I propose to offer a brief account
of the position, structure, and probable origin of these insulated
strata.

Geographical range.—Tracing these unconformable rocks frem
New York towards the southwest, they are found to constitute a
nearly continuous mountain chain, extending from the western
side of Long Pond, past Macapin and Green Ponds, to a point
west of Succasunny. From the State line to the Pequannock, the
belt consists of a single ridge, somewhat broken down in some
places by denudation—this is known as the Long Pond or Raflen-
berg Mountain; but from the Pequannock southwest for several
miles the belt is double, the shorter range forming the Copperas
Mountain, and the longer parallel one the Green Pond Mountain,
ending north of Succasunny.

These ridges are for the most part remarkably straight, while
their summits are nearly level. Throughout considerable dis-
tances they present a succession of bold precipitous escarpments,
facing invariably the east-southeast. The strata dip in all cases to-
wards the west-northwest, at an angle which is somewhat varia-
ble, but which is usually about 30°.

The almost perpendicular outline of these ridges on their south-
eastern side, the repetition of the same rocks in the two adjoining
ranges, and their dipping towards the same quarter, are facts
which strongly indicate the existence of one or more extensive
longitudinal dislocations of the strata. We can hardly conceive
how a mere denudation of the surface, unaccompanied by a disrupt-
ing movement along certain lines, could have given to the topo-
graphy of this formation its present peculiar features.

The Green Pond Mountain terminates in three oval-shaped out-
lying hills in the prolongation of the main ridge, separated from
each other and from it by transverse valleys or notches; through’
one of which the Morris canal has been carried. A fourth low hill,
not precisely in the same line with the others, commences a little
south of these and extends longitudinally towards Flanders. It
would appear to belong to a different formation from the others,

173

being manifestly an insulated remnant of the sandstone, Forma-
tion I., of the Appalachian series.

Composition and Structure—The formation we are describing
embraces two principal members, which preserve their respective
characters with very great uniformity. The lowest of these,
which reposes sometimes on the primary rocks at the foot of
the adjoining hills, sometimes on the lower strata of the older
secondary series, originally forming the bed of the valley, is a
conglomerate easily recognised. This rock consists of a rather
fine-grained compact red sandstone, occasionally argillaceous,
imbedding rounded, water-worn pebbles of various dimensions,
generally composed of white quartz. When these pebbles are
large and diversified in their colour and composition, as happens
in certain beds, and when the paste is less abundant and more
argillaceous than usual, the whole mass possesses a considerable
resemblance to the less calcareous varieties of the Potomac
marble. Bowlders of a rock having these features lie strewed in
great numbers in many parts of the red sandstone region east of
the Highlands, extending as far as the Hudson, and traceable to
this stratum of the Green Pond Mountain.

In the inferior beds, the character of the rock is somewhat dif-
- ferent; being in many places almost white, and consisting chiefly
of a white sandstone, thickly studded with white quartz pebbles.
These layers are conspicuously seen in the outlying low hills,
near the southern termination of the Green Pond Mountain; they
are also visible at many other points, as, for example, ten miles
north of Macapin Pond. Their contiguity to a tract of white sand-
stone of the older series, Formation I., suggests this rock as the
probable source of the arenaceous materials of these beds. We
thus find in this, as in other formations, that the lowermost layers
are derived from the more immediately adjacent rocks, being
deposited during the first influx of the currents, before time had
elapsed for the introduction of the sediments from more distant
quarters. Ascending a little, the beds of the lower part of the con-
glomerate become progressively more tinged with the red matter,
so prevalent throughout the higher portions of the formation.

The other division of the formation overlies the former, and
is a compact argillaceous red sandstone, much resembling the
firmer varieties of the red shale of the district east of the
. i5*

174

Highlands. It is seen well developed about one mile north of
the head of Green Pond, where it forms the point of the Green
Pond Mountain, near the notch or dislocation which traverses it
two miles south of the Pequannock. Both in this vicinity and
in other parts of the range, this stratum is divided by a system
of oblique cleavage joints, which cross the general plane of the
dip nearly at right angles, having an inclination of about 45° to-
wards the southeast. These joints impart to much of this rock
a slaty structure, calculated readily to mislead the observer
respecting the true direction in which these strata have been ele-
vated. The conglomerate is in like manner jointed by planes of
cleavage, but at far wider intervals; being divided into large
massive cuboidal blocks. These joints observe the same direc-
tion and dip as those in the overlying fine-grained red sandstone
and shale.

The total thickness of the formation, including the conglomerate
and the red sandstone, probably exceeds six hundred feet; but
from the appearance of great faults or dislocations in these strata,
the determination of their precise depth is attended with much
uncertainty.

Of the probable Origin of the Formation.—F rom the wholly in-
sulated position of these unconformable strata, encompassed on
all sides by rocks of older date, and from the nonappearance
hitherto of any organic remains of a distinctive kind, by which to
infer their age and mode of origin, we are prevented from arriving
at any very satisfactory views regarding the particular circum-
stances under which they were produced. The striking analogy
which they bear, however, to the strata of the middle secondary
series both in composition and appearance, and their lying in the
same unconformable manner upon the previously uplifted rocks
of the Appalachian group, induce us to consider them as deposits
from the same mass of waters. This suggestion acquires addi-
tional weight, when we reflect that the long and narrow valley
embracing this belt of conglomerate and sandstone, opens imme-
diately into the great basin of the middle secondary series. From
the denuded condition of the southwestern portion of the Green
Pond range, and from the apparently natural outlet which German
Valley would afford for the waters in their passage across this
mountainous district, it seems not improbable that these rocks

175

once filled the bed of this valley throughout its whole length as
far as Clinton. At the final elevation of the red shale and sand-
stone rocks, if, as we suppose, these strata were also uplifted, the
extensive dislocations to which they have obviously been sub-
jected, will account for the removal of a portion of the beds, ex-
posed as they must then have been to the full violence of the
floods thus set in motion.

PART II.

GEOLOGY OF THE SOUTHERN DIVISION OF THE STATE.

Introductory Remarks.

Tue strata of the southern half of the State arrange themselves
in two distinct groups, and belong to two separate periods. The
oldest or earliest deposited of these groups is proved, by the
character of its organic remains, to have originated during the
latest eras of the secondary period, while the more modern belongs
to an earlier epoch of the succeeding tertiary dates.

In tracing these deposits over any considerable area, we disco-
ver that the whole series, though nearly horizontal, possesses an
appreciable dip towards the southeast. As a consequence of this
slight inclination, the lower strata rise successively to the surface
as we advance towards the northwest; those at the bottom of
the series forming the northwestern boundary of the region, where
they repose upon the more steeply dipping beds of the middle
secondary and primary formations, between Trenton and the
Raritan river.

A gently undulating line, drawn from Shark Inlet on the
Atlantic coast, to Salem, separates the secondary and tertiary
groups. The district to the northwest of this line comprises only
the former, while that to the southeast contains the latter. The
tertiary region is extensively overspread, however, by a deep
covering of nearly white oceanic sand, destitute of organic
remains. We are thus precluded, not only from ascertaining
definitively to what precise date we ought to refer this super-
ficial stratum, but the extent to which it conceals the tertiary and
secondary deposits. The tracts in which the former are actually
exposed near the surface, are comparatively inconsiderable.

177

CHAPTER I.

OF THE UPPER SECONDARY SERIES, EMBRACING THE GREENSAND
FORMATION.

General Description.— Adopting as hitherto the ascending order,
we shall describe first the upper secondary formations lying to
the northwest of the line above designated. This series -includes
naturally five separate sets of beds, the characteristic features
and composition of which, commencing with the lowest, are as
follows:

First. A group of sands and clays of several colours and
of somewhat variable constitution, but frequently of extreme
whiteness and remarkable purity. Among these occur beds of
pure potters’ clay. This division of the general series rests, along
its northwest margin, from the Raritan to the Assunpink, in an
unconformable manner upon the middle secondary rocks, and
from the Shipetaukin to the Delaware upon the upturned strata
of the primary belt. It contains towards its upper beds much of
the dark blue sandy clay, which is also associated with the over-
lying greensand, from which it is not separated by any well-
defined limit.

Second. A somewhat mixed group, consisting of beds almost
wholly composed of greensand in a loose and granular condition,
alternating with and occasionally replaced by layers of a blue,
sandy, micaceous clay. This is the “ greensand formation,”
properly so called. The greensand having become extensively
employed in agriculture as a fertilizer of the soil, the bed in
which this mineral is the chief ingredient has acquired the name
of marl. The various features assumed by these strata in the
different parts of the extensive tract which they occupy, will be
specified in another place.

Third. Immediately overlying the greensand formation near
its southeastern border, we find several limited exposures of a
yellowish granular limestone of rather crystalline structure,
and frequently siliceous composition. This rock exists in rather

178

irregular thin flaggy bands, usually from one to three inches
thick. Between these we often find thin layers of loose granular
calcareous sand, identical, or nearly so, with the matter of the
rock, but destitute of cohesion.

This formation contains a profusion of organic remains, many
of which belong in like manner to the underlying greensand,
though some occur in it alone. Resting usually in direct contact
with the greensand stratum, it contains often a moderate pro-
portion of the green granular mineral, sprinkled throughout its
mass.

Fourth. A yellow very ferruginous coarse sand, containing
sometimes a small proportion of the green mineral. ‘This stratum
is in some places thirty feet thick. In the Nevesink Hills and in
one or two other localities, it occurs as a soft sandstone, con-
taining hollow casts of several characteristic fossil shells of the
greensand formation. Throughout much of the central portion of
the greensand region, this bed is in the condition of a loose sand,
but abounds in organic remains in the state of solid casts, showing
the interior form of numerous bivalve and univalve shells. The
thin limestone next under it being very partially developed, this
yellow sand generally rests in immediate contact with the green-
sand deposit, the two beds sometimes blending almost insensibly
into each other.

Fifth. Resting upon the former and constituting the highest as-
certained member of the upper secondary series in the State, there
occurs a coarse brown ferruginous sandstone, sometimes passing
into a conglomerate. It is composed of translucent quartzose
sand, small fragments of felspar, and pebbles of white quartz,
cemented together by a dark brown paste of oxide of iron.
The green mineral in detached grains is likewise a common
ingredient. The position of this rock is usually upon the summits
of the insulated outlying hills, which rise occasionally above the
general plain of the “ marl region.”

In employing for these upper secondary deposits of the State,
the title of “ greensand series,” and for one member of the group
that of the “ greensand formation,” I wish not to convey the
impression that I regard these strata as the equivalents in the
strict sense of the word, of the greensand formation, so called,
of Europe. The remarkable abundance of the green granular

179

mineral in some of these beds, and its existence in greater or
less degree in all, besides the obvious identity between most of
the fossil genera in this and the European group, suggest the
propriety of adopting the above name, as characterizing the
peculiar composition of the deposit, and its relationship to the
rocks of a well known system in other countries. But much yet
remains to be ascertained respecting the organic remains of the
two deposits in the respective continents, before we can determine
more than approximately the true amount of affinity subsisting be-
tween them. The existence of but one or two species common to
the European and American formations, renders it indeed a ques-
tion of much uncertainty, to what part of the cretaceous period as
defined in Europe, we are to refer the origin of these deposits of
New Jersey, nor are we able positively to decide, merely by the
relationship of the genera, whether the cretaceous period em-
braces both the commencement and termination of the American
greensand series.

SECTION I.

Of the Potters’ Clay Formation ; Geology of Middlesex and part

of Mercer counties.

Geographical Range.—The southern edge of the middle se-
condary district marks the northwestern boundary of this forma-
tion, from the mouth of Lawrence’s brook to the Shipetaukin
creek, between which and the Delaware, the gneiss rocks of the
Assunpink form its limit. Advancing southwestward, the forma-
tion occupies a narrow belt along the Delaware, from Borden-
town to a point opposite New Castle, the southeast bank of the
river being its northwest boundary. Its inferior beds do not
appear in Pennsylvania, having been washed away by the cur-
rents which excavated this part of the valley of the Delaware.

In some places the river in its meanderings cuts across the belt
almost to the southeastern margin, where it is bordered by the
lower beds of the greensand deposit. ‘This is the case at Borden-
town, where the greensand approaches the Delaware within half
a mile. Where the river on the other hand recedes towards the
northwest, as for example opposite Tullytown, the lower beds of

180

the series are preserved; and hence we have in that locality the
white clays and sands of the “clay banks.”

This lowest division of the upper secondary series passes into
the greensand formation by a gradual transition; we cannot,
therefore, delineate very precisely, the limit which separates the
areas of the two formations. It will be traced with as much
minuteness as practicable when we give the ascertained boundaries
of the greensand or marl tract, being the northwestern margin of
that important belt. It will be sufficient for our present object to
state that this line, bounding these inferior clays and sands on the
southeast, ranges nearly parallel with the railroad which unites
South Amboy with Bordentown, lying southeast of it at an
average distance of about three miles. Between Bordentown-
and Salem it preserves a rather greater distance from the Dela-
ware.

Besides the tract thus traced, embracing most of the deposits
of pure potters’ clay in the State, there occurs an isolated bed of
remarkably pure white clay and sand, which obviously belongs
to this formation: it lies between Woodbridge and the Raritan,
having escaped the destructive diluvial action which has swept
away so large a portion of these lower beds of the formation in
other places.

Composition.— White and yellowish sands, and white-blue and
mottled-blue, and pink clays, used in pottery, occur abundantly in
the lower and middle portions of this formation. Higher in the
series these beds become less predominant, and we meet with a
larger proportion as we ascend, of darker, more ferruginous and
carbonaceous sands and clays. A very common material among
these is a dark, sandy, micaceous clay. ‘This deposit when moist,
is usually lead-coloured or a dark-blue, or sometimes almost
black. In this state it is somewhat plastic, becoming as it dries,
of a light bluish-gray colour. It is rarely free from a consider-
able proportion of ordinary siliceous sand and mica, both usually
in a state of minute division. The dark colour seems chiefly to
arise from a small quantity of carbonaceous matter in a diffused
condition. Relics of vegetation, such as carbonized wood or
lignite, amber, and retinasphaltum, often occur in it, but par-
ticvlarly the first. It exhales the smell of marsh mud, though
this gives place occasionally to that of sulphur, emitted by

181

the decomposing sulphuret of iron, which is often copiously
present.

To the reaction of the alumina and sulphuret of iron, assisted
by the oxygen of the atmosphere, we are to attribute the incrus-
tation of sulphate of iron and sulphate of alumina sometimes seen
upon its surface, imparting to the mass an astringent and acid
taste, and endowing it with properties very noxious to vegetation,
Some layers, containing a larger quantity than usual of the sul-
phuret of iron, acquire even a brown colour at the surface, caused
by the amount of the hydrated oxide of iron produced by decom-
position. The impervious texture of this material, causes the
water which reaches it through the overlying porous sandy beds,
to appear along its upper margin in the ravines and other de-
pressions of the surface wherever its outcrop occurs. Much of
this water passing through the adjacent beds of greensand, which
are often charged like the blue clay with the decomposing sul-
phuret of iron, becomes impregnated to some extent with the
sulphate of iron, producing a precipitation under favourable cir-
cumstances, of the hydrated peroxide of iron, in the form of bog
iron ore, and yellow ochre.

To exhibit more definitely the composition of this blue earth, I
here submit a chemical analysis of a specimen procured from the
base of the Nevesink hills, on the Raritan bay, which will show
the average composition of a very abundant variety of the
stratum.

Analysis of the Blue Astringent Micaceous Clay.

Silica, - - - - - 35°75
Alumina, - - - = - 39°25
Protoxide of iron, - - - 12°10
Sulphuric acid, - - 3s - 1:95
Carbonaceous matter, - “ 1:00
Potash, »»- > - - - 0:30
Magnesia, - - - - - 0-25
Muriate of soda, - - 2) altrace.
Oxide of manganese, - - - a trace.
Water and volatile matter, - : 7:00

97:60

16

182

That certain portions of this deposit may be rendered available
for enriching the soil, I firmly believe. The statement already
made, that there sometimes exists in it a considerable share of
the greensand, in other words, of the fertilizing material of the
marl, is enough to encourage those who possess it and not the
genuine marl, to give it their attention. Notwithstanding the very
frequent, we may say the almost invariable occurrence, of the
astringent matters, which are in themselves so unequivocally
deleterious to vegetation, certain precautions may be adopted,
such as must make it a valuable auxiliary to the farmer in places
where the genuine marl lies too remote. The recommendations
respecting the mode of using it, will be found in the chapter on
the economic geology of the greensand formation.

This material alternates both with the lighter coloured clays
and sands already spoken of, and with the greensand, which it
overlies in some parts of Monmouth county. It is well exposed
for examination in the cuttings upon the Camden and Amboy
railroad. Containing occasionally a small proportion of the
green grains, and resembling somewhat, when moist, the true
greensand or marl, it is frequently applied to the soil through a
misconception of its true nature, to the serious detriment of the
crop.

ECONOMICAL GEOLOGY.

White Clay of Woodbridge-—About one mile southwest of
Woodbridge, near the level of a small stream on the road to New
Brunswick, there occurs an insulated deposit of white clay and
white sand, in which both materials are of remarkable purity.

This local bed is surrounded by the red shale rocks of the
middle secondary series, and would seem to be a remnant of the
lowermost layers of the upper secondary group, lying in a de-
pression of the surface where it has escaped removal during the
general denudation of the strata.

Beneath about ten feet of reddish diluvial matter, derived from
the adjoining red shale, we find a bed of pure white sand, re-
gularly stratified, and dipping gently westward. Its thickness is
about ten feet. This sand is much esteemed as an ingredient for
the manufacture of fire bricks. Underneath the sand lies the

183

white clay, in a bed about eight feet thick; when dry it is very
nearly white, some portions of it, however, have a very slight
bluish tinge. It is much used in the manufacture of pottery and
fire bricks. The purer varieties are admirably adapted for
making the glaze for paper-hangings, being employed for this
purpose.

About three-fourths of a mile southwest of this excavation,
another similar deposit is exposed in some recent diggings. The
clay at the latter place surpasses. even that of the former in
whiteness, and in its exquisite smoothness of texture.

In the descending order, the beds at this place are, first, diluvial
matter ten or twelve feet thick, then a layer of sand, and under
this again the clays between seven and eight feet thick. These
consist of an upper bed, somewhat sandy, but well adapted for
making fire bricks, two feet in depth, and a lower layer, also two
feet thick, remarkable for its whiteness and fine texture. This
latter kind is particularly esteemed for making the glaze for paper.
Immediately below this lies another bed of pure clay, having
also a fine texture. It is white with reddish or pink blotches; its
thickness is from three to four feet. It is an observation of the
workmen, that when the clay is pure the sand associated with it
is so likewise.

White Clay, Albion Mill—A similar deposit of white clay and
sand, occurring like the last near the bottom of the series, is to
be seen not far from the Albion Mill, about five miles southeast of
Trenton.

The clay at this spot, though moderately white and free from
ferruginous matter, is mingled with rather too large a proportion
of fine white sand, to suit it for making the better kinds of stone-
ware. It is not improbable, however, that its composition is
such as to fit it for the manufacture of good fire bricks.

Clay Banks of the Delaware—About half way between Bor-
dentown and Burlington, beds of clay of somewhat analogous
composition occur along the southern shore of the Delaware, in
the line of cliffs called the “Clay Banks.” The deposit in this
place presents more variety than is visible in the other localities
described.

The clay, though in some layers nearly white, is in many places
slightly tinged or spotted with pink or bluish stains. It is dug to

184

some extent and employed for making pottery. Besides the
whiter varieties, there occur others of a dark blue colour, having
more or Jess sand and ferruginous matter in their composition.
Imbedded between the layers of clay are seams of white and
yellow sand.

The clay beds of this locality would appear to occupy a middle
position in the formation, being higher than those southwest of
Woodbridge, but inferior to the strata of potters’ clay near
South Amboy, to be next described. They lie very nearly in a
range with the white sandy clay seen near Albion Mill, with
which also a dark blue argillaceous bed is associated.

Potters’ Clay, South Amboy.—Somewhat higher in the order of
stratification, we find beds of bluish white and mottled clay, well
suited for the manufacture of a much esteemed variety of stone-
ware.

This highly useful material occurs in a bed several feet thick,
ranging along the shore of the Raritan Bay from South Amboy,
for a space of about two and a half miles, to the marshes called
the Cheesequakes. ‘The stratum is nearly horizontal. Its upper
surface is washed by the tides upon the beach; a mile farther to
the southeast, it rises twenty-five feet above the shore, and a few
hundred yards beyond this, it gently sinks again, so that two
miles from Amboy it is overlaid by the ordinary dark-blue as-
tringent clay. There are two principal banks or quarries where
this clay is procured on a rather extensive scale. In that nearest
to South Amboy, which goes under the name of Churchill’s bank,
the mass has been excavated to the depth of twenty-five feet.
The lowest bed, which is that principally used, is a grayish blue
clay, which, on drying, becomes nearly white. Besides a large
proportion of alumina, it contains a large quantity of silica, in a
minutely subdivided condition. Scattered through it occur nume-
rous dark specks, which seem to be sulphuret of iron in a state of
decomposition. After the surface of this clay has been exposed
for some time to the air, these specks acquire a light yellow
colour, which most probably arises from the oxidation of the iron.
It is a curious fact, that the clay in which these dark specks are
seen, is preferred in the manufacture of the stoneware, for which
the material is chiefly used. Resting immediately above this
layer, there is a variegated or mottled variety, often most beau-

185

tifully stained with red, green, and other coloured blotches.
This, which is called peach blossom clay, is mixed with the former
sort to make a particular variety of the pottery. About a fourth
of a mile further to the southeast is another very extensive clay
bank, the property of Mr. C. Morgan. At this spot, the lowest
layer seen above the beach, is a variegated gray sand of un-
known thickness, its surface being near the level of the tide.
Immediately upon it rests the bed of clay, which varies in thick-
ness from nine to twenty-one feet. It closely resembles Churchill’s
in composition, and is a very superior clay for making the kind
of pottery called stoneware. In one part of the bed the clay
contains a little mica in very minute scales. This is said greatly
to injure its value as a material for making pottery. Other
portions contain the dark specks supposed to be useful. Some
bands in this portion of the stratum are reddish, and furnish the
peach blossom clay. A white astringent efflorescence, probably
a sulphate of alumina and iron, or a kind of alum, is found upon
a certain layer near the upper part of the bed. This seems to be
derived from the decomposition of the sulphuret of iron, which
appears to be a characteristic component of the whole series of
strata of which this clay bed is a member. The upper surface of
the clay, though slightly undulating, is pretty nearly horizontal.
Immediately upon it there occurs in many places a layer of sand
of a few inches thickness, which contains vegetable relics, such
as fragments of wood completely carbonized, and in the state of
lignite, and also small pieces of nearly pure charcoal. Amber
also occurs here, called rosin by the workmen.

Resting on the top of this layer is a bed of variegated sand,
streaked with white, gray, red, and other colours. This is in some
places ten feet thick, and over it, at various elevations, is a layer,
generally about two feet thick, of the tough dark-blue astringent
clay, showing a yellowish efflorescence of copperas upon its
exposed surface. It contains, as this material very frequently

does, a good deal of mica in minute scales, and a considerable

_ proportion of common siliceous sand. This upper bed increases

in thickness as we advance towards the meadows of the Cheese-

quakes, and southeast of Morgan’s excavations none of the under-

lying clay has been found. In all probability it lies a little below

the level of the beach, though it is possible that it may either
16*

186

thin out or graduate into the dark clay that elsewhere lies
above it.

On the top of the uppermost bed of sand above described, but
somewhat nearer South Amboy than the commencement of the
dark astringent clay, there is a yellow and much coarser sand,
extending up to the soil. In this place its total thickness above
the white clay is twenty feet. The materials of this uppermost
layer are sometimes as coarse as gravel; and it seems to belong
to the superficial diluvium, as it has an irregular undulating out-
line which strongly contrast with the nearly straight surfaces of
the beds beneath. A similar exhibition of the diluvial sand and
gravel reposing upon the other sands and the dark clay here
described, may be witnessed at various places upon the Camden
and Amboy railroad, and also conspicuously in the banks at
White Hill, where the line separating the two deposits is very
distinct. It is undulating, as if the original surface of the lower
bed had been scooped by the currents that carried along the
sand and gravel now forming the upper or diluvial stratum.

ANALYSIS.
Potters’ Clay, Morgan’s Bank, South Amboy.
Description.—Mottled white and red throughout the mass, but
more particularly on the surface; highly gritty between the
teeth; by calcination at a full red heat becomes of a brick red
colour.
In 100 parts it contains:

Silieay oe : - = 67-6
Alumina, - - - 15:8
Peroxide of iron, - - 5:6
Water, - : - = 9:3
Loss, - - 5 1-7
100°0

SECTION II.

Greensand Formation—* Marl.”

Geographical Range-——The second division of the upper
secondary series, which, in allusion to its peculiar composition,

187

I have entitled the greensand formation, is by far the most
interesting portion of the whole deposit, whether we consider the
curious properties of its chief constituent, the interesting relations
of its numerous fossils, or the highly valuable use as a fertilizing
agent, to which a large portion of the stratum is applicable.
Dipping at a very gentle inclination towards the southeast, its
Jower layers rise to the surface, and are finally lost towards the
northwest, along the irregular denuded margin already referred to
as forming the southeastern limit of the underlying potters’ clays.
Traced in detail, this northwestern boundary of the greensand
formation may be described with sufficient accuracy as com-
mencing at the southern shore of the Raritan Bay, a little to the
northwest of the western termination of the Highlands of Neve-
sink, about the mouth of Compton’s creek. Its course from this
point, where the underlying strata are seen to rise above the level
of the water, is a little south of west, past the small village of
Mount Pleasant, to Deep run. From Deep run, the visible limit
of the greensand takes a nearly south direction for nearly two
miles, and then a westerly one to the Matchaponix creek, which
it crosses about two miles southeast of Spotswood. It next
crosses the Manalapan, two miles above the mills marked on the
map as Mount’s, previously sweeping in a somewhat concave
line to the southeast. Between the Manalapan and the Millstone
streams, it presents a similar curve towards the southeast,
appearing on the latter about half a mile above the spot called
the Red Tavern. Thence, bending as before, first to the south
and then to the west, it crosses Rocky brook, half a mile below
Millford. From this point its course is first south to Empty run,
then southwest to Doctor’s creek, a little above Allentown, and
then west-southwest along the southern side of the same stream
to Crosswick’s creek, which it passes about half a mile above the
little village called Groveville. From Crosswick’s creek to Bur-
lington creek the line of the greensand is nearly straight, crossing
Black’s, Craft’s, and Burlington creeks, each at points about one
mile and a half from the Delaware. Passing the latter stream, it
recedes somewhat from the river, meeting Rancocus creek about
four miles above its mouth, near Franklin Park and Pensaukin
creek, one mile west of Moorestown. Its course next, is a little
more westward, to Cooper’s creek, down which the stratum

188

extends, to within four miles of Camden. Sweeping again
slightly to the south, the line reaches Timber creek, one mile and
a half from the river. Thence its direction is nearly west-
southwest as far as Raccoon creek, the line crossing in the
interval Woodbury creek near Woodbury, and Mantua creek
near Sandtown. Passing Raccoon creek about one mile below
Swedesboro, it deflects more to the south, and pursues a nearly
straight course to its point of termination near Salem, crossing
Oldman’s creek at Sculltown, and Salem creek about two miles
west of Sharptown.

The undulations of this northwestern boundary of the green-
sand appear to arise less from any variations in the amount of
the southeast dip, which is nowhere more than barely perceptible,
than from the inequalities in the denudation of the stratum along
its margin, and more especially from the irregular overlapping of
the diluvial covering, which, particularly in the eastern side of
Middlesex, conceals the true limit of the formation in all the
higher tracts of ground between the streams, and gives to the
visible boundary the curving outline alluded to. The denuding
flood, which has evidently swept along the valley of the Dela-
ware, seems, in curving to the south, to have cut away a large
portion of the greensand, which originally extended southwest
of Oldman’s creek, giving to it a wedge-like form at its termi-
nation near Salem. The true strike or direction of the stratum
would carry its northwest margin to the Delaware somewhere
opposite Newcastle, as shown by the position of this side of the
formation, where it reappears in the State of Delaware, in the
vicinity of Bowersville. ‘The oblique course of the denudation
across the belt is further manifested in the nearly north and south
direction of its margin on the western side of the river. In con-
sequence of this, the southwest point of the formation in New
Jersey lies opposite the general southeast margin in Delaware;
and the northwest termination of the tract in the latter State, is
in the prolongation of the general northwest edge already traced
across New Jersey as far as Oldman’s creek.

From the point where the northwest boundary of the green-
sand commences, the formation is exposed for a considerable
height along the base of the Nevesink Highlands, the whole
distance from Compton’s creek to the mouth of the Nevesink

4

189

river. South of this point it appears along both sides of Shrews-
bury river, east of the head of which it is seen skirting the sea
coast. From about two miles north of Long Branch, southward
as far as Shark Inlet, the stratum reaches almost to the ocean
beach, being only hidden in places by a superficial covering of
white sand, blown for a short distance inland from the shore.
We do not find it either at the sea side or for three miles in the
interior any where south of the estuary of Shark river. Buta
little west of the Poor House the edge of the formation crosses
Shark river, and takes a gently undulating course towards the
southwest.

In consequence of the wooded character of the country along the
southeastern side of the greensand, and the irregular and obscure
manner in which the white sands overlap this stratum, the south-
east boundary is much less capable of being distinctly defined than
that on the northwest. Aiming at as close an approximation to
accuracy as the structure and condition of the region will permit,
I have traced the margin of the formation from Shark river to
where it crosses the Manasquan river, about one mile east of
Squankum. Its general course thence is nearly westward until
it is seen on Tom’s river, which it crosses about a mile northeast
of Goshen. Assuming in this neighbourhood a nearly southwest
direction, and passing near the above village, it ranges about a
mile to the southeast of New Egypt, and passes Scrabbletown
to Rancocus creek, which intersects it about one mile east of
Pemberton. Thence it passes about one mile and a half south-
east of Vincentown, and a mile southeast of Medford, reaching
Timber creek near Clementon. It lies rather more than a mile
to the southeast of Blackwoodtown. On Mantua creek, the
limit of the greensand is rather further to the southeast, being
visible near a mill-dam about two miles in a direct line from
Glassboro. Upon Raccoon creek, its position is nearly two miles
to the southeast of Mullica Hill, and upon Salem creek about half
a mile east of Woodstown. Pursuing the same general south-
west direction, it is seen on Mannington creek, three-fourths of
a mile to the southeast of Mannington Hill; beyond which to
Salem, where it terminates, it follows very nearly the margin of
the meadows of Fenwick’s creek.

The belt embraced between the two lines thus delineated, has

190

the form of a long and acutely tapering wedge, the base of which
is traced by the coast of the Atlantic Ocean and Sandy Hook
bay—the point being marked by the limit of the firm land north
of Salem. A slight inclination of the surface of this formation
may be shown to exist uniformly from its northeastern towards
its southwestern extremity. Independently of proofs derived
from the known elevation of the country at various points, we
have evidence of the correctness of this statement by merely
observing the position which the belt occupies in relation to the
streams in the different portions of its range. In Monmouth,
where it is widest, it includes the head waters of nearly all the
streams which empty either into the Atlantic Ocean, or the
Raritan and Delaware rivers. But, crossing Burlington, Glou-
cester, and Salem counties, its position as we advance south-
westward is nearer and nearer to the mouths of the several
creeks entering the Delaware. The whole of the strata have
been manifestly uplifted to a greater height in Monmouth than
elsewhere, which circumstance, in connexion with the less ex-
tensive denudation of the northwest side of the belt, readily
explains the breadth of the formation in that quarter.

The area here designated as including the whole of the visible
greensand formation, embraces also several local, insulated tracts
of the other overlying divisions of the upper secondary series.
These are obviously but the remnants of strata which at one time
spread themselves extensively over the greensand. The general
southeast dip of all these deposits, renders their existence beneath
the superficial sands of the region to the southeast extremely
probable. To the almost universal destruction of the yellow
sand and brown sandstone, which form the two upper strata of
the series, we are to ascribe, I conceive, the deep and general
covering of loose yellowish and white sands which conceal
the rest of the formations throughout so large a portion of the

region southeast of the greensand belt.

Composition of the Greensand or “ Marl’ Formation.

The greensand formation comprises, strictly speaking, several
subordinate beds, all belonging, however, to two principal varie-
ties. In the first of these, the green granular mineral is the pre-

191

dominant and characteristic ingredient. The second consists, on
the other hand, of a dark-blue clay, mingled with more or less
siliceous sand. This latter material constitutes the usual floor
upon which the true greensand deposit rests; and it occurs, in
like manner, especially in the northern and eastern portions of
Monmouth county, both above the uppermost visible greensand,
and included between its beds in one or more alternations.
Appearances would seem also to indicate that these two deposits
replace each other in the same bed, when traced for considerable
distances. Indications of this passage from the one material to
the other are chiefly discoverable in the lower portions of the
formation, or along its northwestern margin. As the same dark
clay, associated with the greensand, abounds throughout the
upper portion of the next inferior division of the series, or that
which we have styled the potters’ clay formation, it is impossible
distinctly to define the lower limit of the true greensand forma-
tion. I shall, for convenience sake, however, group all the strata
below the lowest bed of greensand, with the division containing
the potters’ clay.

The external characters, and usual chemical composition of
these blue astringent clays lying adjacent to the greensand, have
been described in the previous section, when treating of the lower
part of the series, to which deposits they more strictly belong
than to the greensand. I shall confine myself, therefore, in this
section to a description of that part of the present formation
which mainly characterizes it, namely, the greensand deposit
itself.

Composition of the Greensand.

Description.—The predominant and often the sole ingredient
in this bed, is a peculiar mineral occurring always in the form of
small dark granules, about the size of grains of gunpowder.
their form is roundish, and they are often composed of two or
three smaller ones united together, a distinctive feature, by which
they may at once be recognised from other dark kinds of sand.
Though they contain on the average nearly fifty per cent. of silica,
they are not gritty, but may be readily bruised between the teeth,
or upon the nail, and some varieties, when moistened, admit of
being kneaded into a half plastic mass, like impure clay. The

192

prevailing colour of the grains is a deep green, though sometimes
the tint is as light as that of verditer. Itis often of a “dall oa
blue, and not nareqaerile of a dark chocolate colour.

Along the eastern side of the marl tract in Monmouth, Bur-
lington, and Gloucester, the stratum comprises very generally two
varieties of the greensand, distinct as to colour, and holding
generally the same relative position to each other. The upper-
most layer, where it appears (for it is not always present), is of a
light and glowing green, having very nearly the hue of the green
paint called verditer; while the lower one is the common dark
variety, of a dull bluish-green, or sometimes of a dull blue colour ~
from adhering clay.

In some instances, particularly where the material constitutes
the soil, the granules possess a brownish colour, the consequence
evidently of the protoxide of iron which they contain, having
undergone upon the surface a change to the condition of the
peroxide. The dull colour so usual to the surfaces of these
grains, when contrasted with the brighter green within the mass,
would appear manifestly to proceed from the same cause. Some
shade of green may be pronounced to be the colour essential to
this mineral, as all the deviations from this tint are attributable
either to oxidation, or to a thin coating of clay, which frequently
encrusts each grain, and from which the deposit is rarely al-
together free. When a mass of the greensand or “marl” is
washed, especially with water to which a small quantity of an
acid has been added, we invariably find the granules assuming a
bright green surface. This colour is also produced in all cases
when we mash or bruise a grain, no matter what may be its
colour externally. By crushing the grains upon a sheet of white
paper, we have an easy and unerring test in the colour of the
streak, by which to recognise this material from all other varieties
of sand.

Though the green granular mineral here described, constitutes
the essential and distinctive ingredient in the greensand stratum,
it rarely exists unassociated with several extraneous substances,
particularly clay and white siliceous sand. These constitute
sometimes as large a proportion as fifty per cent. of the bed,
causing much variety in its external aspect, and influencing ma-
terially its properties as an agricultural agent. The sand which

193

is generally white or semitransparent quartz, existing usually in
relatively small amount, the clayey matter being ordinarily the
most abundant. This latter is of several tints, but is commonly
of alight gray or lead-colour. It is also occasionally chocolate-
coloured, brown, and even nearly white. Coating frequently the
surfaces of the green grains, it conceals their true colour, im-
parting its own hue to the entire mass. As it is somewhat adhe-
sive when moist, it gives to the stratum where it is abundant the
character of a partially plastic clay. Besides the white sand and
this clayey material, we often find a minute quantity of finely
divided mica mingled with the greensand.

Subjecting the marl in the compound condition in which it
occurs in the stratum to analysis, mechanically performed, J have
ascertained the relative proportions of its several ingredients for
a great number of localities. A large body of results will be
presented in the section treating of the economical details of the
greensand formation. But in the mean time, with a view to
exhibit the prevailing composition of the stratum, the seven fol-
lowing analyses are presented.

ANALYSES OF THE “ Mart.”

A specimen from the pit of William Little, near Middletown Point,
Monmouth county.

The material at this locality is of a light stone-gray, inclined to
greenish. Closely examined, the green granules are easily dis-
tinguishable. Ata little distance it has the aspect of a light-
coloured clay. The greensand procured from it by washing is
of a light green colour.

When separated into its constituents, 100 parts, afford :

Greensand, - 46°78
Clay, - - 53:27
Quartzose sand, - none.

100-00

A specimen from Thorp’s pits, near Squankum, Monmouth county,
(upper part of the bed.)

This marl is of a dark leaden-gray colour, owing to the pre-
yi

194

sence of a large proportion of clay. The greensand when
freed from this adhering clay by washing, is of a dark green.
Besides the clay, the mass contains a considerable proportion of
quartzose sand.

100 parts, afford :

Greensand, - 58°36
Clay, - - 27°64
Quartzose sand, - 14:00

100-00

A specimen from Horner’s pits, near the Bridge, Hornerstown, Mon-
mouth county.

' The colour of this marl is a rather light green. After having
been washed, its greensand though consisting chiefly of bright
green granules, contains, also, some of a brown ferruginous
colour. Besides a rather large amount of clay, this marl pos-
sesses a small per centage of quartzose sand.

100 parts, afford :

Greensand, - 75:90
Clay, - - 20-10
Quartzose sand, - 4:00

100-00

.

A specimen from John Woolston’s pit, one-fourth of a mile south of
Birmingham, near Rancocus creek, Burlington county.

This marl is but slightly cohesive. Its colour is a leaden-gray.
Being washed, the greensand exhibits a clear green colour; it
occurs in small granules, with a little quartzose sand admixed.

100 parts, afford :

Greensand, - 82-60
Clay, : = 10:40
Quartzose sand, - 7:00

100:00

195

A specimen from the pits of Mr. Hoffman, one mile and a half east
of Barnesborough, Gloucester county.

In its native condition, this marl is of a rich green, rather
lighter than the medium tint. The greensand which it yields by
washing, is of a somewhat darker colour, but uniform. The
granules are moderately large, and with very few intermingled
grains of common siliceous sand. Minute grains of carbonate of
lime occur in it, but in trivial proportion.

100 parts, afford:

Greensand, 2 85°58
Clay, 1) lisp Aagaeae
Quartzose sand, - 1-00

100-00
A specimen from Jonathan Riley’s pits, at Woodstown, Salem county.

The marl of this locality is of a dark dull greenish gray, with
a tint of brown. This colour is owing to the ferruginous character
of its clay. It is almost entirely free from quartzose sand, but
contains a very small amount of carbonate of lime in minute
granules. When washed, its greensand is of a very deep tint,
nearly black; some of the grains, however, are brownish.

100 parts, afford :

Greensand, - 88:28
Clay, Sibel a
Quartzose sand, - none.

Carbonate of lime, a trace.

100-00

A specimen from the farm of James Smith, Mannington Hill, Salem
county.

This marl has a rather green colour, of the average depth of

tint. When washed, the greensand is of a rich dark green.
100 parts, afford :

Greensand, - 88:80
Clay, - - 10-20
Quartzose sand, - 1-00

100-00

196

Besides the aluminous and siliceous matters here recorded as
usually present with the greensand in the general mass, there
occur occasionally several other substances, which, though com-
paratively minute in quantity, are possessed of active properties.
Some of these materials are probably deleterious, while some are
undoubtedly beneficial in their action upon vegetation. The
substances referred to are carbonate of lime, already mentioned,
sulphate of tron, sulphate of alumina, sulphate of lime, and sulphate
of magnesia ; also, phosphate of iron.

They appear to be derived, mainly at least, from constituents
in the clay, and only very partially, if at all, from elements in the
greensand itself.

The carbonate of lime, in most instances, we can trace to fossil
shells and other organic remains, imbedded in the stratum. The
sulphate of iron, obviously proceeds from the action of the at-
mosphere and moisture on the sw/phuret of tron, so abundant in
the clay; and the sulphate of alumina from the union of a portion
of the sul, huric acid thus developed, with the argillaceous earth
of the clay; while the sulphates of lime and magnesia may result,
either from the combination of the same acid with some of the
lime and magnesia, sometimes presetit in a minute share in the
green mineral, or more probably from its reaction on the car-
bonates of lime and magnesia, existing like the sulphuret of iron
in an insulated state. The phosphate of iron, is no doubt derived ~
from phosphoric acid, traceable to the animal remains, acting on
oxide of iron.

Several of these substances develope themselves upon the mass
of the marl after it has been dug and exposed to the atmosphere,
in the form of a white efflorescence, encrusting alike the clayey
matter and the granules of greensand, with a delicate crystalliza-
tion resembling a light frost. Collected and carefully examined
and analyzed, this efflorescence will be found almost invariably
to consist when it is of a pure white, of either the sulphate of
magnesia, or sulphate of lime, (gypsum,) the latter predominating ;
and sometimes, these two occur united. In some instances, we
recognise it to contain the sulphate of magnesia, (epsom salts,) in
sufficient quantity to be distinguishable by its taste. A yellowish
tint and an astringent flavour are apparent when it consists chiefly
of the sulphates of alumina and iron. The carbonate of lime

197

more generally shows itself, not in the shape of an efflorescence
on the surface like the others, but dispersed in minute granules
throughout the body of the marl. Many of these calcareous
granules are grains of dolomite, analogous in composition to the
magnesian variety of the limestone, which overlies the greensand ;
whence probably the true source of the sulphate of magnesia
above referred to. When the traces of shells are very numerous
in the bed, and their conversion into the sulphate of lime has
happened on the large scale, the gypsum forms a conspicuous
part of a soft white clayey matter derived from the shells and
interspersed among the green grains. The mixed mass of car-
bonate and sulphate of lime is then usually in a yellowish white
chalky condition. Sometimes we may detect the gypsum in the
marl in the shape of small regular crystals of transparent selenite,
at times so minute as only to be detected by the magnifier.

Various fossil shells and other marine organic remains, amount-
ing to considerably more than one hundred species, are scattered
through the greensand. They do rot occur very evenly distri-
buted, but lie together in groups or colonies, forming layers, often a
few feet in thickness, which extend over moderately large spaces.
These collections of fossils would seem to be most abundant in
those parts of the stratum which consist largely of the greensand.

The water percolating through the overlying sands, and also
through the pervious greensand itself, has effected, and is daily
effecting, important changes in the condition of the shells and
other fossils; sometimes replacing their carbonate of lime with
oxide of iron, sometimes removing it altogether, and leaving a
mere mould forming either an inner or an outer cast, and some-
times obliterating nearly every trace of their former presence.
We can perhaps nowhere meet with a better exemplification of
the various alterations induced by the infiltration of water through
porous strata, than are to be witnessed in these greensands and
their associated deposits, where numerous substitutions of the
elements are continually in progress, and where every species of
dissolving and cementing action is hourly going forward upon
an extensive scale.

The oxide of iron, the chief sources of which, as I have hinted,
are the sulphuret of iron in the clays of the greensand and the
ferruginous particles of the overlying yellow sands, is frequently

1 hg

198

so abundantly introduced into the marl stratum, as to act the
part extensively performed by it in nature, of a cement, bind-
ing firmly together into a semi-rocky mass, the materials with
which it is in contact. When this occurs, the marl is often ren-
dered too hard to be excavated by the ordinary implements.
When indurated or solidified from this cause, it is most commonly
in the form of large round concretions, from the size of a bushel
to that of a barrel, lying in horizontal layers, generally near the
top of the stratum. These masses thrown out and exposed to the
frosts of a winter, most usually crumble down into the friable
state so essential to form a useful marl; and the material seems
to be not in any way impaired in its virtues, from having been
united in such firm cohesion. When the cementing action has
proceeded farther, a regular stratum of indurated greensand rock
exhibits itself. Such may be seen in some portions of the cliffs
on the bay side in the Nevesink hills, large blocks of it strewing
the beach, and offering some beautiful specimens of a fine brown-
ish-green rock, in which the green granules are dispersed through
a cement (or paste), deeply coloured by oxide of iron, giving the
whole a pleasing variety of tint.

The above descriptions embrace the principal changes which
the materials of the greensand formation seem to have undergone
since their original deposition. They claim attention, not merely
for the elucidation they afford of some of nature’s most impor-
tant operations, performed in her quiet laboratory by her silent
but potent chemistry, but for the valuable practical suggestions
they furnish concerning the greensand deposit in its interesting
light of a fertilizer of the soil.

The total thickness of the greensand formation, estimating it
from the bottom of the lowermost layers abounding in the green
granular mineral to the overlying yellow ferruginous sands, or
the limestone bed when this is present, may be stated approxi-
mately at about one hundred feet. The only place in the whole
district where it is practicable to ascertain, with any approach to
accuracy, either the depth of the formation, or the relative situa-
tion and number of the separate beds which it comprises, is along
the shore of Sandy Hook bay in the cliffs of the Nevesink high-
lands. This, the only coast section of the strata, is still an im-
perfect one; large masses of the upper beds, fallen from above,

199

covering the lower deposits near the water side. It would appear
from what we behold in these cliffs, as well as from evidence
collected throughout the “marl region,” that the greensand con-
stitutes generally but a single stratum, conceived to be continuous
beneath the whole district, and to be itself in many places, more
than thirty feet in thickness. That it is occasionally divided into
two or even more subordinate thinner beds by bands of clay
and sand, which are sometimes interpolated, and swell to a
thickness of several feet, is obvious enough from the features seen
in many excavations. But it should rather be considered as a
deposit remarkable for the permanency of its composition, thick-
ness, and external features. Owing to the large amount of water
which it usually contains, the greensand is rarely penetrated in
the numerous diggings which are made in it for the marl, to a
greater depth than about twenty feet, the pits becoming at that
limit too wet to be prosecuted deeper.

In one or two instances, wells have been sunk through the
stratum, and the depth of the greensand ascertained to be about
thirty feet, as already mentioned.

Specific Gravity.—The specific gravity of the green granular
mineral, carefully freed from all extraneous adhering matter is,
according to several] experiments cautiously made, about 2-65.
Three different specimens, taken from remote localities, gave for
the two lowest each 2°63; for the highest 2-70.

The hardness of this mineral varies materially, being dependent
somewhat upon the time elapsed after it has been dug; it is softest
when moist and recently uncovered. Freshly extracted, its hard-
ness often does not exceed that of tale; but when long uncovered
and dry, it nearly equals that of gypsum.

It would appear by experiment to be entirely insoluble in water,
both cold and boiling; but it dissolves with tolerable facility in
any of the stronger acids, though different specimens vary ma-
tzrially in this respect.

Chemical Composition of the Green Mineral.

From a number of analyses of the greensand, selected with the
greatest care for the purpose, and ascertained to be entirely free
from extraneous matter, it would seem that this mineral is not

200

quite uniform in its composition, but exhibits slight variations in
the proportions of its principal constituents.

The following results will serve to display its prevailing chemi-
cal nature, and the moderate fluctuation of the several ingredients:

Greensand of Thorp’s Marl, Squankum.

Description.—Colour, a dark olive-green ; granules of a medium
size; it composes 58°36 per cent. of the marl of the upper part of
the bed, and 72-36 per cent. of the lower.

Composition.—'n 100 parts:

Silica, - - - - 51-00
Alumina, : - : 6:50
Protoxide of iron, - : 21:55
Potash, - = - - 10°50
Lime, - - - - a trace.
Magnesia, - : - 1-08
Water, - 5 : = 9-00

99°63

Greensand of Joseph Vanderveer’s Marl, Freehold, Monmouth }
county.

Description.—Colour of the granules, rich green ; size, small;
composes 70 per cent. of the upper part of the bed, and 92 per
cent. of the lower.

Composition.—In 100 parts:

Silica; - = - = 50-00
Alumina, 2 . : 7:00
Protoxide of iron, - 3 22-00
Potash, - A = 2 11-00
iaime sane - = - 1:00
Magnesia, - z - a trace.
Water, - : 2 : 9-00

100-00

Greensand of the Marl of Poke Hill, near Plattsburg, Burlington
county.

Description.—Colour of the granules, a rich dark olive-green ;

201

their size, rather above the medium ; composes 98 per cent. of the
marl.
Composition.—In 100 parts:

Silica, - - - . 50°75
Alumina, - - : 6:50
Protoxide of iron, - - 22°14
Potash, - - - - 12-96
Water, - : = = 7°50

99°85

Greensand of the Marl from the Pits of Thomas Edwards, Bur-

lington county.

Description —Colour a rather light grayish green; the granules
somewhat less than the medium size; it forms 93°51 per cent. of
the marl.

Composition.—In 100 parts:

Silica, - - - - 51:00
Alumina, = - - 6:75
Protoxide of iron, - - 22-00
Potash, - - - - 11:00
Lime, - - - - a trace.
Magnesia, = - - none.
Water, - - - - 9-00
99°75

Greensand from the Marl at Evesham, Burlington county.

Description.—Colour of the granules, a medium tint of green;
their size rather large; constitutes almost the whole of the marl.
Composition.—In 100 parts:

Silica, - - - - 48°50
Alumina, = = = 7°50
Protoxide of iron, - - 22-80
Potash, - = = = 11-00
Water, - 2 E ; 9°50

99°30

202

Greensand from the Marl of Josiah Heritage, two miles and a half
east of Barnesborough, Gloucester county.

Description—Colour of the granules, a very dark olive-green
approaching black; size rather large; forms 93°70 per cent. of the
marl.

Composition.—In 100 parts:

Silica, - - - - 47°50
Alumina, - - - 7:84
Protoxide of iron, - - 23°78
Potash, - - - - 11-11
Lime, .- - - - 0°50
Water, - - 2 9:00

99°73

Greensand from the Marl of Michael Allen’s pits, one mile and a
half east of Mulhca Hill, Gloucester county.

Description —Colour of the granules, brownish green; they
are of about the medium size ; constitute 96°36 per cent. of the
marl.

Composition.—In 100 parts:

Silica, ~ S 48°50
Alumina, 2 - - 7:00
Protoxide of iron, - - 21-40
Potash, = Z : 12:90
Lime, - - 2 - a trace.
Magnesia, - : 1:00
Water, ~ 2 . 8:80

99-60

Greensand from the Marl of Elijah Horner’s pits, one mile and a
half southwest of Mullica Hill, Gloucester county.

Description Colour of the granules, a rich green, rather
darker than the average; size, large; forms 90°75 per cent. of
the marl.

203

Composition.—In 100 parts:

Silica, - = = - 51-09

Alumina, - - - 8:23

Protoxide of iron, - - 21:99

Potash,

Magnesia, : ; aie

Water, - = - - 5°51
100°88

Greensand from Marl of Benjamin Coulson’s pits, three miles north-
east of Woodstown.

Description.—Colour of the granules, a dark rich olive-green ;
size, rather large ; constitues 90 per cent. of the marl.
Composition.—In 100 parts:

Silica, - = - - 48°35
Alumina, ~ = 2 9°35
Protoxide of iron, - = 20°86
Potash, : = - 11-73
Lime, - - - - 0:50
Water, - - = - 9-00

99°79

Greensand from Marl of Allen Wallace’s pits, two miles and a
half west-northwest of Woodstown, Salem County.

Description.—Colour of the granules, a dark green; size, rather
large; constitutes 90 per cent. of the marl.
Composition.—In 100 parts:

Silica, - - - : 48°40
Alumina, - - - 7°30
Protoxide of iron, - - 23-00
Potash, - 2 = 11:47
Lime,z* - - - - 1:20
Water, - - E 8:15

99°52

204

Greensand from Marl of Jonathan Cauley’s pits, three-fourths of a
mile northwest of Woodstown.
Description.—Colour of the granules, a rather dark olive-
green ; size, large; constitutes 86 per cent. of the marl.
Composition.—In 100 parts:

Silica, - - - - 48°45
Alumina, - - - 6°30
Protoxide of iron, - = 24°31
Potash, - - - 12-01
Lime, - - - - a trace.
Water, - - - 8-40

99°47

Greensand from Marl of Samuel White’s pits, Woodstown.
Description.—Colour of the granules, the medium tint of green;
size, somewhat large; composes 88°26 per cent. of the stratum.
Composition.—In 100 parts:

Silica, - - - - 50°16
Alumina, - - - 6:00
Protoxide of iron, - - 24:74
Potash, - - - 11-70
Lime, - - - - a trace.
Water, - - - 7:00

99-60

Greensand from Marl of Paul Scull’s pits, three miles northwest
of Sculltown, Salem County.
Description.—Colour of the granules, a very dark green; com-
poses 91:5 per cent. of the marl.
Composition.—In 100 parts:

Silica, - - - = 51°50
Alumina, - - - 6°40
Protoxide of iron, - - 24-30
Potash, = - = 9-96
Magnesia, - : - a trace.
Water, - - - 7-70

99-86

205

Greensand from Marl of James Smith’s pits, Mannington Fill,
near Salem.

Description Colour of the granules, a rich dark olive-green;
size, rather large; forms 88-8 per cent. of the marl.
Composition.—In 100 parts:

Silica, - - = = 50-00
Alumina, : = : 6:99
Protoxide of iron, - - 20:99
Potash, - - - 10-99
Water, - - - 10-00

98:97

Comparing the details of these several analyses, we perceive
that the greensand even when of the greatest purity is not
absolutely constant, either in the nature of the ingredients which
enter into its composition, or in their relative proportions. The
per-centage of the silica is seen to vary from 475 to 51:5; that of
the alumina from 6 to 9:35; that of the protoxide of iron from
20°86 to 24-74; that of the potash from 9:96 to 12-96; and that
of the water from 5:5 to 9°5. We find, moreover, that, in some
instances, besides these clements, ime enters into the constitution

. of the greensand, in other cases magnesia; while occasionally
both occur. The amount of these earths is, however, always
inconsiderable.

From the above series of analyses it appears that the mean
proportion of the siica is approximately 49-5 per cent.; that of
the alumina 7-3 ; of the protoxide of iron 22°8; of the potash 11:5;
and of the water 7-9 per cent.; while the dime when present
seldom exceeds one half per cent., and the magnesia is rarely
more than a mere trace.

A comparison of the greensand of New Jersey with that of
Europe shows no essential difference in their chemical nature.
M. Berthier, an able French chemist, has analyzed that of the
vicinity of Havre, in France, and reports the following as its

composition.
18

206

Greensand of Havre, in France.

Composition.—In 100 parts:

Silica, 2 - - - 50
Alumina, - - - - 7
Protoxide of iron, . - 21
Potash, : - - - 10
Water, “ : - 2 11
Loss, - - - - 1

100

The late lamented chemist, Dr. Edward Turner of London,
also examined with great care the chemical constitution of the
greensand of Kent, in England.

His experiments gave in the 100 parts:

Silica, - - - - 48°5
Alumina, - - - 17:0
Protoxide of iron, - 3 22:0
Potash,» = . - a trace.
Magnesia, - - - 38
Water, - - - : 7:0

98°3

The absence of potash in the green granules of the English
greensand, and the large proportion of magnesia are facts not a
little remarkable.

ECONOMICAL RELATIONS OF THE GREENSAND FORMATION.

Abundant evidence might be adduced to prove that the true fer-
tilizing principle in marl is not lime but potash. The analyses which
have been made, give us in several cases no lime at all, and where
a small proportion of lime is present in the green granular mineral,
it is in a combined state, chemically united with the other ingre-
dients, and not traceable to the organic remains, which are in
many of these instances not present in the stratum. Besides, the
quantity of shelly matter, even where the shells are plentiful, is so

207

disproportionately small, and the matter of the shells often so firm
and unsusceptible of that easy disintegration, necessary to form a
calcareous marl adapted to act speedily upon the crop, that the
striking effects witnessed from the marl can in nowise be attributed
to the trivial amount of lime which the shells may occasionally fur-
nish to the land. Nevertheless, as some feebly beneficial effects may
possibly arise from this source, it may be of service to the agri-
culturist, in choosing between different fossiliferous marls, to at-
tend to the nature of the particular fossils, and the state of more
or less decomposition or change in which they are to be found.
It must be borne in mind, that a large portion of the visible marl
stratum is immediately overspread by a very porous layer of yel-
low ferruginous sand, and that this introduces to it a perpetual
supply of water, furnished with great regularity as from an im-
mense filter. From the upper or ferruginous sand it must descend
charged often with a considerable amount of the oxide of iron,
as may be seen in the abundant ochreous sediment which it almost
always deposits as it issues from the surface or upper part of the
mar] bed. It is ready, therefore, to precipitate this oxide of iron
upon any substance capable of displacing it from the water, and
meeting with the more soluble carbonate of lime of the shells, an
interchange.of materials arises, and the calcareous matter of the
shells is dissolved and carried away, while the oxide of iron takes
its place. Hence we often see the shells of a deep yellow or brown
colour, and upon inspection they are found to consist less of car-
bonate of lime than of oxide of iron. In such case they are to
be regarded as wholly inert upon the soil, as, in fact, so much
useless matter, usurping the place of a far more serviceable sub-
stance, the greensand or marl. But this is not the only change
which seems to have been effected in the foreign materials of the
marl by this unceasing infiltration of water. I have before alluded
to the peculiar composition of the overlying dark-blue astringent
clay, and to the fact that it frequently contains a sensible quantity
of the sulphate of iron or copperas; and that both this clay and
its astringent impregnations are very often mingled through the
granular marl itself. Now the water from either of these sources
must dissolve in its passage a considerable quantity of the cep-
peras (an easily soluble substance), and where there are shells or
other calcareous fossils, it must carry with it a portion of the car-

208

bonate of lime derived from them. These two substances coming
together in a state of solution, a chemical reaction, of course, en-
sues, both the sulphate of iron and carbonate of lime are decom-
posed by the mutual affinities of their ingredients, and the result
is a precipitation of the oxide of iron of the former, and a combi-
nation of the sulphuric acid and the lime to form sulphate of lime
or gypsum. ‘That such is the fact is apparent from our finding,
in many cases, a sensible amount of gypsum, either in the earthy
state or in minute crystals intermixed with the marl; and from
our observing besides, that when the gypsum is in greatest plenty,
we can most generally discover a strong sulphurous odour, an
evidence upon grounds before explained of the existence of sul-
phuret of iron, undergoing a conversion into the sulphate of iron.
It will suggest itself to every one, that the existence even in small
quantities of so potent a stimulant to vegetation as gypsum, must
have a powerful influence in modifying the useful properties of
the marl containing it. Yet it must not be inferred from this, that
the efficacy of the greensand is owing to the gypsum which [|
have shown to be frequently present. ‘The comparative inertness
of plaster upon the sandy soils of parts of the region where the
marl has never been applied, as in several places near Salem, is
a fact in itself sufficient to overthrow this notion, even if it were
not true that very many marls which do not contain gypsum in
any shape, are endowed with the highest fertilizing power.

Directions for Selecting and Analyzing the Greensand.

The valuable fertilizing properties of the greensand, and the
extensive use which is made of it in agriculture throughout nearly
the whole of the region which it occupies, suggest the propriety
of our offering in this place, some practical directions for select-
ing, analyzing, and applying it.

In seeking for the marl stratum in neighbourhoods where it is
likely to occur, but where a covering of any of the superficial
deposits obscures it, the primary point to be remembered is, that
the true greensand stratum is the lowest accessible deposit of the
region. We should find out, therefore, the deepest depressions of
the land, such as the meadows and natural ravines, and by the
use of an auger or other instrument for boring the ground,
several feet in length, ascertain whether the stratum lies suffi-

209

ciently near the surface to be easily and economically uncovered.
A rather sure guide to the marl is afforded by the aspect and
composition of the earth existing at and near the surface. Should
it be at all greenish, or contain upon close inspection, any of the
green granules, the probability is that the marl lies beneath at a
very moderate depth, and the chances augment when we find our
borings bring up an increasing proportion of this mineral as we
descend. I have repeatedly found the position of the marl stratum
indicated by the trickling forth of the water from the foot of a
bank, for the water is almost invariably seen to issue along the
top of either the dark clay or the true marl.

For judging of the quality of a marl by observation, some fami-
liarity with the multiform aspects which it assumes is indispen-
sable. The leading rule, however, is to bear in mind that the
fertilizing efiicacy of the compound, resides in the minute round
greenish grains which compose most, or sometimes all of it; and
that it seems, moreover, to be dependent upon the proportion in
these green grains of those powerful alkaline stimulants to vege-
tation, potash and lime, but especially potash. The first thing
then, is to approximate to the relative quantity of the green grains
in the whole mass, and this may be effected with a greater or
less degree of accuracy in several ways. The simplest and
readiest method is to employ a small pocket magnifying-glass,
and to become familiar with the dark-green grains, so as to dis-
tinguish them at once from other dark varieties of sand which
sometimes occur associated with them. A little practice will
very soon enable one to use the glass expertly, and to arrive at
a pretty true estimate of the probable per-centage of the green
granules. But as these granules cannot sometimes be distin-
guished from the grains of ordinary white flinty sand, or from
other kinds, in consequence of the particles being all alike coated
with a thin film of the dark cementing clay, it will be useful to
adopt some method of bringing out under the magnifier their dif-
ferent characteristics of colour and form. Let the mass be washed
in a large glass tumbler, and repeatedly agitated with the water
until as much of the clay as possible has been detached from
the grains. After pouring off the turbid water by repeated rins-
ings, and permitting it to settle until clear, we may estimate the
comparative quantity of clay in different marls by the relative

18*

210

amount of sediment which subsides. If we wish to be more
accurate, we can weigh out a given quantity of the marl, then
pursue the above plan, and decant the clear water from the clay;
and after thoroughly drying the clay, weigh it to ascertain its
amount. Having got away most of the clay, we should spread
out the granular matter upon a sheet of paper and dry it, when
there will be no farther difficulty in distinguishing, by their colour
and lustre, the foreign impurities from the grains of true marl;
and also of estimating the relative abundance of each. When
the marl to be examined contains much clay, I would recom-
mend the experiments to be made upon a regularly weighed
quantity, weighing both the clayey and the granular portions. A
delicate apothecary’s balance will commonly be found accurate
enough. Another more expeditious, though less accurate method,
is merely to dry the marl, spread it extremely thin upon a sheet
of white paper, and then hold it near a window or in the light, to
examine it carefully by the magnifier. The flinty sand, though
stained with clay, may then be clearly discerned in consequence
of its transparency; whereas when we inspect a solid lump, all the
particles upon the surface are nearly alike dark.

A useful suggestion is, to place a portion of the marl upon a
hot shovel or on the top of a stove, when all the granules will
change from their ordinary green tint to a light red or brick co-
lour, while the other materials of the mass sustain little alteration.
This will often render obvious to the naked eye the proportion of
the green grains.

When there is a yellowish or whitish incrustation upon the
marl after the moist surface has remained for some time exposed
to the weather, it is indicative of the existence of a portion of
either copperas or sulphate of alumina, the hurtful nature of which
has already been explained.

An astringent inky taste will very often detect the presence of
these noxious substances at times when no such efflorescence
shows itself. If the quantity be too small to betray them dis-
tinctly to the palate, and we are still in doubt as to their presence,
other more rigorous tests are within our reach; and as these
astringent matters are so unquestionably pernicious in their action,
it is of importance to have the means of determining in what pro-
portion they abound in different marls. This can be effected with

211

precision only by a systematic chemical analysis, but their exist-
ence can be made to appear by the following simple tests. Put a
small portion of the marl in a flask or other thin glass vessel;
pour upon it some pure water, and heat it moderately. After
causing the water to dissolve in this way as much as possible,
remove the heat, and let it settle; then decant the clear fluid into
some glass vessel, such as a wine-glass. If there is any copperas
present, it will be evident upon adding to the fluid a little lime-
water, which will produce a milky turbidness that after a little
while will become stained of a yellowish-brown colour. The
milkiness is owing to the formation of gypsum, and the brown
colour to oxide of iron from the copperas. Or in lieu of this, add
a solution of oak bark; and if copperas be present, we shall have
a dark inky colour at once produced.

A good marl will, upon being squeezed in the hand, fall asunder
again rather than bake into a tough doughy mass; and upon
being left in heaps to dry, will assume a light grayish green co-
lour and be extremely crumbly. It seems to be a very general
characteristic of the better class of marls, that they throw out a
white efflorescence or crust upon those grains which are most
exposed to the air: hence the very light colour externally which
some heaps of marl possess. This crust I have already shown
to consist usually of the sulphate of lime (gypsum), sulphate of
magnesia, and carbonate of lime. A drop or two of strong
vinegar, or any strong acid, will produce an effervescence or
frothing if it be the carbonate of lime; and should nothing of this
kind take place, we may set it down to be gypsum. Of course,
from the minuteness of the quantity of the white coating, much
care and accuracy of observation are demanded in doing this, in
order to avoid erroneous conclusions.

Marls deemed equally good with the kind showing the efflo-
rescence, very frequently occur, exhibiting none of the white in-
crustation.

It does not seem that any general rule can be given for distin-
guishing the fertilizing properties of a marl by its mere colour, as
it must appear from what has been said, that the peculiar shade
of colour is frequently owing to the colour of the intermingled
clay. When the mass, however, is comparatively free from clay
or common sand, and consists of little else than the greensand,

212

observations go to show that the rather dark green variety is
more potent in its effects than the very light green, which some-
times overlies it.

The presence or absence of shells I look upon to be a point of
but little moment, for I find that several of the most active marls
in the region show no traces of fossils. The whole amount of
carbonate of lime in the shape of fossils, and in that of the occa-
sional white incrustation upon the grains, can in very few in-
stances amount to one per cent.; while, as analysis shows, the
lime chemically combined with the other ingredients in the green
grains, is sometimes one per cent., and the potash nearly twelve
per cent.

There yet remains, however, a more important, and by far
more difficult inquiry, namely—into the exact constitution of the
green grains, in order to determine the per-centage of the several
ingredients—or the richness of the marl in potash and lime. I
had entertained hopes that the external aspect of the grains
might perhaps depend in part on the presence and proportion
of these bodies, and that mere inspection, after multiplied ana-
lyses were made, might enable any one following certain direc-
tions, to inform himself whether a mar] abounded in these essen-
tials or not. But, I find that so far from being a mineral of
definite and constant proportions, as some mineralogists have
regarded it, the greensand is in fact a compound which fluctuates
considerably in its external characters, and its chemical compo-
sition. The numerous analytical results which I have presented,
will abundantly prove this. It is manifest, therefore, that we
possess no shorter method to discover the exact quantity of the
potash, than to subject the marl to a systematic chemical analysis.

Three different plans have been pursued in procuring the com-
position of the marls described in this work. The first consisted
in separating, mechanically, that is to say, by washing and
selecting the several ingredients, the greensand, the clay, and the
quartzose sand, together with any carbonate of lime which may
be present. The second, in analyzing systematically the green
granular mineral, with a view to determine accurately its consti-
tution. The third, in partially analyzing the marl for the purpose
of ascertaining the proportion of its chiefly efficacious element,
the potash. Besides determining the relative quantity of potash

213

by the two latter methods, it has been approximately esti-
mated for a series of specimens too numerous to be subjected
to the more operose process of analysis, by ascertaining by the
first mode the amount of the green mineral, and then calculating,
from the average per-centage of potash, the proportion in which
it prevails in the particular marl.

Though it is not presumed that among those engaged in agri-
culture, more than a very few persons possess the requisite
chemical skill, or the facilities for this species of research, yet
for the sake of such as may chance to be competent to execute
this kind of analysis, I have thought it well to introduce a state-
ment of the method of analyzing the mineral in question. Several
plans, modifications of the same general method, have been tried
for the purpose of arriving, if possible, at some mode sufficiently
simple to make it practicable by those who possess but a limited
knowledge of analytical chemistry. But the nature of the com-
pound seems not to admit of either a very direct or expeditious
mode of operation.

Method of analyzing the Greensand.

1. Digest the mass in a flask with pretty strong muriatic acid,
by a sandbath heat for at least three days, or boil it actively for
five or six hours. Every thing is dissolved but the silica, which
must be filtered, ignited, and weighed.

2. Precipitate the oxide of iron and alumina by ammonia and
estimate them together, and detach the alumina by caustic potash.

3. Evaporate the ammoniacal solution to total dryness, and
heat the mass to incipient redness, to expel the muriate of ammo-
nia. There remain the chlorides of calcium, magnesium, and
potassium, which redissolve in water, dividing the liquor.

4. To one half add oxalate of ammonia, and separate the lime,
then by ammonia and phosphate of soda separate the magnesia.
Subtract the combined weight of these two computed as chlo-
rides, from the original triple chloride, and we have the chloride
of potassium.

5. Now evaporate the other half again to dryness, and dissolve
up all the chlorides of calcium and magnesium by alcohol, and
dry and weigh the residual chloride of potassium. If further

214

check is necessary, convert this into chloroplatinate of potassium,
and estimate the potash from this.

Suggestions for correcting the Noxious Effects of the Astringent
Clay underlying and associated with the Greensand, and for
using u as a Marl.

From the descriptions of this stratum already presented, it
appears that the action of this astringent mass upon the crop is
decidedly pernicious, when the material is employed in any
amount beyond the most stinted doses; and the cause of its poi-
sonous property would seem, judging from the chemical analyses
made, and from other evidence, to be attributable to the acid re-
action of the astringent ingredients which it possesses, namely,
the copperas and sulphate of alumina.

Copperas, though a neutral salt, is well known to chemists to
exert an acid reaction, and hence we are not to be amazed that
a clay containing it in obvious quantities, should burn, or more
strictly poison, the vegetation. Knowing, as we do, the source
of the deleterious properties of the clay, a few simple correctives
suggest themselves, and such as any one wishing to use this sub-
stance as a substitute for marl may adopt.

My first recommendation to the farmer who is about to make
use of this clay upon his soil, is, that he be careful to select, when
he has the choice, that variety which contains the green granular
material of the true marl, and to avoid altogether the kind which
is wholly destitute of this substance. When the green grains are
pretty numerous in the mass, as they are near Spotswood, Bur-
lington, Camden, and generally upon the northwest side of the
marl tract, I would then advise its use, but guarded by the follow-
ing precautions. Let the clay be dug several months before it is
to be scattered on the land, and Jet it be spread out in broad,
shallow, flat heaps, where the rains may soak through it and earry
away the copperas and sulphate of alumina, which, from their
well known solubility, will be easily dissolved and washed out.
The green mineral does not dissolve in water, and hence, while
the rains will purify the mass, no loss of its more active portions
ean happen. Numerous attempts at using this clay as a marl
have shown, that though noxious at first, it is often permanently

215

beneficial to the land, after the second, third, or fourth year;
a fact which I attribute to the gradual escape of the astringent
matter by the rain. Though I do not think that the exposure
of even an entire winter will always suffice to rob the clay of
all the sulphates (copperas, &c.) which it may contain, yet it
bids fair to do much good, and therefore deserves a careful
trial.

I have to offer another, and I think, far more promising sug-
gestion, for making the better portions of this stratum beneficial
in their effects upon the soil, Chemists are aware that both the
sulphate of iron and the sulphate of alumine are decomposed by
caustic lime ; and the antidote I propose is founded upon this fact.
My recommendation is, to add to every heap of this spurious
astringent marl, a small quantity of freshly burnt lime, and to
mingle them thoroughly together. The sulphuric acid of the
copperas or alum earth, or of both if present, will pass over to
the lime and form sulphate of lime (gypsum or plaster), the value
of which, as a stimulant to vegetation, is well understood; the
other ingredients, the oxide of iron and clay, will on being libe-
rated, contribute also towards improving the texture of the soil
should it be sandy. A bushel of lime to every hundred bushels
or five tons of the mass, will in most cases be sufficient to neu-
tralize all the astringent matter present, and to convert it into, or
rather replace it by, gypsum. The dressing of an acre of sucha
mixture will contain of the green marl, of gypsum, and of uncom-
bined lime and lime in a state of carbonate, in all probability fully
enough to impart to the soil a most decided improvement in point
of fertility.

Lastly, | would recommend, for this astringent marly clay, the
same course so appropriate also in regard to lime: I mean the
practice of making a compost of the substance with the common
manure of the farm.

This, like the former suggestion, is justified by good chemical
reasons. In the fermentation of animal manure, ammonia always
escapes in greater or less quantity ; and ammonia, like lime, has
the power of decomposing the sulphates of iron and alumina.
In this case, however, gypsum is not a product.

From what is here said, it will be obvious, that when a field
has been made sterile by the indiscreet use of this caustic clay, a

216

ready and certain remedy will be found by spreading upon every
acre a few bushels of newly made lime.

Should these hints, which are designed to render useful cer-
tain portions of this lower stratum, receive their final corrobo-
ration from experience, we may consider that the area of the
region susceptible of improvement by marling without the expense
of hauling the material from a distance, has been in many districts
doubled or tripled in extent. To ascertain whether the clay pos-
sesses a sufficient share of the green granules to warrant a trial
of it upon the land, it may be necessary to employ the aid of a
small magnifying-glass, which will be found by every farmer to
be of indispensable use in the discrimination of all greensand
marls.

SECTION III.

Limestone of Salem, Gloucester, and Burlington counties.

Resting immediately over the greensand formation, we find
occasionally the locally developed and thin calcareous rock
which we have defined as the third formation of the upper se-
condary series. Though unimportant as regards its thickness
and the extent of surface which it occupies, it derives value from
its usefulness as a source of lime, in a district having no other
calcareous stratum, while considerable interest attaches to it,
from the number of its fossils, and its affinity to an extensive and
thick formation in the southern States, the dower limestone of
Alabama.

Geographical Extent—The general range of the stratum is from
a point a little northeast of Salem, past Woodstown, Black wood-
town, Mullica Hill, Vincentown, and New Egypt to Prospertown;
beyond which J have been as yet unable to discover a trace of it.
But it is not to be inferred that it exists as a stratum of much
extent or importance throughout all of this long line. It has
hitherto been detected at distant points only, and nowhere but in
Mannington, Salem county, does it cover a wide area, or possess
more than a very insignificant thickness. It lies along the south-
eastern edge of the visible marl tract, and if it dips at all, it is
towards the southeast, to underlie the ferruginous sands. At its

217

greatest width, four miles northeast of Salem, it can be traced
over a breadth of three-fourths of a mile. Its thickness in the
same neighbourhood, as proved by a well sunk through it, is as
great in one spot as twenty feet ; though elsewhere in the same
vicinity it is not more than six or eight. Near Vincentown it
seems to be still less; and upon the branches of Crosswick’s creek,
it is reduced to less than one foot. The stratum preserves its
prevailing structure and position, at its several localities, leaving
us in no uncertainty as to its identity.

Composition and Aspect.—This rock is usually a soft yellowish
or straw-coloured limestone, with a structure varying from sub-
crystalline to coarsely granular. It is often replete with organic
remains, the disintegrated shells and corals, and other fossils,
composing a considerable portion of the mass. Much of the
rock contains impurities, as sand, clay, and oxide of iron; and
its value as a limestone is therefore very variable. At times it is
little else than a sandstone, in which the sand is cemented to-
gether by a trace of lime. It occurs with this character in loose
rounded masses, resting above the marl, at Woodstown. Again
it exists as a firm calcareous rock. This is its state in some
places near Salem, in Mannington township. In the several
accompanying analyses, the composition of the leading varieties
of the rock may be accurately seen. This limestone is nowhere
to be found in thick massive strata; on the other hand, it occurs
only in thin horizontal beds, or irregular layers, not often more
than four or six inches thick, and commonly separated by a thin
parting of sand and carbonate of lime in small grains, to all
appearance an incohering mixture of the same materials that
form the rock itself. The more calcareous beds have not un-
frequently some resemblance to some of the thin oolitic strata of
England, in consequence chiefly of the granular form of much of
the carbonate of lime; together with the innumerable fragments
of fossils which sometimes form almost half of the mass. Unless
attentively observed, this rock will appear much more sandy than
it actually is, owing to some of the carbonate of lime being in the
shape of small round yellow grains, like those of sand. Occa-
sionally, especially near the bottom of the stratum, where it
adjoins the marl, it contains a sensible proportion of the green
grains, sometimes in such abundance as to unfit it for being burnt

19

218

into lime, the potash and other ingredients of the green mineral
serving to vitrify it and form a kind of slag.

LOCAL DETAILS.

Mannington.—The most southwestern spot at which this lime-
stone appears, is east of Mannington Hill, about three miles from
Salem. It occurs in the banks bordering the meadows of Man-
nington creek, on the farm of Miss Parrot, lying two or three
feet beneath the surface. The stratum here is of a light yel-
lowish colour, and consists of minute fragments of shells and other
fossils in a chalky state, together with grains of quartzose sand, and
a few granules of greensand, all invested by particles of carbonate
of lime. ‘The rock is in thinly bedded layers from three to five
inches thick, accompanied by a calcareous sand, differing in no
respect but in the absence of cohesion from the material of the
limestone. This sand rests both above and between the more
solid layers.

Analysis of the Limestone from the farm of Miss Parrot, near
Mannington Mill, Salem county.

Description.—Colour, straw-yellow, granular, and subcrys-
taline ; fossiliferous.

Composition.—In 100 parts:

Carbonate of lime, - - 81°35
Carbonate of Magnesia, - 1:95
Alumina and oxide of iron, 1:04
Insoluble matter, - - 14-64
Water and loss, - - 1-02

100-00

On the farm of Mr. W. Petit, in the vicinity of Mannington
Hill, the limestone displays itself in considerable thickness, the
layers of the rock alternating with the calcareous sand as de-
scribed above. This locality is about a mile and a half south-
westward from the poor-house.

The following analysis exhibits the proportion of carbonate of
lime in the limestone of this neighbourhood.

219

Analysis of the Upper Secondary Limestone of Woodnut Petit,
Salem county.

Composition.—In 100 parts:

Carbonate of lime, - 77°80
Carbonate of magnesia, - 1:20
Alumina and oxide of iron, 1°80
Insoluble matter, - - 17:80
Water, - : - - 1:12

99:72

This stratum is destined to prove of signal service to the agri-
culture of all the region adjacent to it; for lime is particularly
useful upon lands destitute of calcareous matter, like some of the
more sandy tracts of New Jersey. The lime from this rock in
Salem, is growing rapidly into use. I would recommend—as
promising to prove highly beneficial—the soft, friable, uncon-
creted parts of the stratum which lie between the solid layers,
especially near the bottom of the formation. Being already in a
pulverulent state, and composed chiefly of carbonate of lime,
with occasionally some of the grains of the green marl, the whole
must constitute a calcareous marl, admirably adapted to ame-
liorate the lands of the surrounding country.

Both the limestone and the calcareous sand occur well de-
veloped on the farm of Mr. J. Ridgeway, near Mannington Hill.
The rock at this place has a subcrystalline texture, being tolerably
well cemented; towards the centre of the layers it is of a bluish
colour. It is quarried to some extent and burned on the spot,
yielding a very good lime. The price of this lime is about nine
cents per bushel. The calcareous sand of this place is also
growing into demand as a marl, and is vended at the rate of
twelve and a half cents per load.

Analysis of Limestone from the farm of Hazleton Stacy, Salem
county.

Description—Colour, straw-yellow, compact, subcrystalline,
and granular; consists largely of the fragments of fossils.

220

Composition.—In 100 parts:

Carbonate of lime, - - 75°56
Carbonate of magnesia, - 1:20
Alumina and oxide of iron, 2-50
Insoluble matter, - - 18-49
Water, - - - - 2:00

99:75

Salem Creek east of Woodstown.—'To the southeast of Woods-
town, upon Salem creek, the limestone is visible in two or three
places, though rather deeply covered by diluvial sand. I cannot
learn that it has attracted attention or been burned for lime. It
seems to be of very local extent, though possibly the main portion
of the stratum has not yet been exposed.

Near Mullica Hill—The limestone is found on the small tri-
butaries of Raccoon creek, at two places about a mile and a half
southwest of Mullica Hill. Though not as highly calcareous as
that near Mannington Hill, it effervesces actively with an acid,
and contains a moderate proportion of shells, in a fragmentary
condition. It occurs in flat thin layers, separated by more or less
of the calcareous sand. Its total thickness has not been ascer-
tained, the stratum having been quarried to a very limited extent
for the purpose of procuring lime. By selecting the more compact
and crystalline portions of this rock, and observing proper pre-
cautions in the burning, it affords a very good lime, for agricultural
purposes. This material is exposed in the banks of a meadow
on Raccoon creek, on the farm of Charles Batten, where it shows
the following beds:

1. Dark micaceous earth, thickness variable.

2. Similar bed, abounding in fragments of white fri-

able shells, - - . - - : 1 ft. 6 in.
3. Soft, porous, fossiliferous limestone, - - 0 4
4. Calcareous sand, with shells, - - - 0 10
5. Gray, compact, subcrystalline limestone, - 108
6. Calcareous sand, - - - - - 236
i

Hard subcrystalline limestone only penetrated to
the depth of eight inches, it is probably con-
siderably thicker, = - - - - - 0 8
The more compact bands of the limestone afford a very good lime.

221

Wear Barnsboro—Two miles and a half east of Barnsboro,
the calcareous stratum occurs near Mantua creek, on the farm
of Josiah Heritage. The layers of the rock are between six
and eight inches thick. It consists chiefly of comminuted frag-
ments of shells and other fossils, and scattered grains of ordinary
siliceous sand, and a few granules of greensand. It is a gray
limestone, the interior of the mass having some degree of com-
pactness, and promises with care in the calcination, to yield a
lime fit for the purposes of the agriculturist.

Analysis of the Limestone overlying the Marl on the farm of Josiah
Heritage, near Blackwoodstown, Gloucester county.

Description.—Y ellowish-gray, granular, and subcrystalline, and
very fossiliferous.

Composition.—In 100 parts:

Carbonate of lime, = 75°0
Carbonate of magnesia, - 1:8
Alumina and oxide of iron, 2:5
Insoluble matter, - - 18-7
Water, - - - - 1:7

99-7

Near Blackwoodstown.—Upon the southern branch of Timber
creek, the limestone is again met with south of Blackwoodstown.
As in the other localities above mentioned, its thin layers are di-
vided by more or less calcareous sand, a bed of which also overlies
it at this place. The relative order of the beds commencing with
the diluvium, and extending to the surface of the greensand
stratum, is as follows:

1. Diluvial sand and gravel, - - - - 3 feet.
2. Yellow ferruginous sand, - - - - Nivea
3. Dark ferruginous clay, very tough, - - - 1 «
4. Gray siliceo-caleareous sand, containing fossils

similar to those of the underlying limestone, ce

5. Yellowish-gray limestone, in thin irregular flaggy
layers, contains several species of shells, and the
eschara digitata in considerable abundance, 2h «
6. Greensand marl, at the level of the stream.
19*

222

Clementon.—In the vicinity of Clementon, on the north branch
of Timber creek, the limestone shows itself in several places,
occurring in thin horizontal bands, about six inches in thick-
ness, imbedded between layers of the calcareous sand. These
layers are some of them two and a half feet thick, furnishing an
abundance of excellent calcareous marl, which is used to a small
amount in the neighbourhood, and with striking benefit to the
crops. The limestone itself is quarried and converted into lime.
The upper surface of the stratum is about twenty-five feet above
the level of the stream, and is overlaid by about five feet of
diluvial matter.

The stratification here presents a somewhat singular anomaly,
the calcareous sand forming in some places tall narrow cones or
eminences, rising almost through the overlying stratam, which
fills the intervals between them. Some of these cones are four
feet high and two or three feet in diameter.

Analysis of the Limestone from the Farm of Mr. Isaac Thompson,
near Clementon, Gloucester County.

Composition.—In 100 parts:

Carbonate of lime, - - 77-0
Carbonate of magnesia, - 1°5
Alumina and oxide of iron, 2-0
Insoluble matter, - - 18-0
Water, - - - - 1-0

99°35

The fossils in this limestone are some of them very beautiful
and in high preservation. Among them occurs the species
Eschara digitata, in vast quantities; also, Spatangus parastatus,
Ananchytes cinctus, and A. fimbriatus, and an echinus; besides
Anthophyllum Ailanticum, Scalaria annulata, Gryphea convexa,
G. Vomer, Flustra sagena, and teredo; together with several
more zoophytes and shells.

Medford.—At Charles Haines’s mill, two miles below Medford,
on the creek, a section is seen exhibiting on the top a greenish
siliceous sand; beneath this, a gray sand some feet thick, contain-

223

ing a small proportion of the green granules, and under this again
the straw-coloured limestone two feet thick.

These beds hold the same order, and are identical with those
above the green marl at New Egypt and elsewhere, towards the
eastern side of the “ marl tract.” One-fourth of a mile from the
mill, the beds have been cut through, in digging a well into the
greensand stratum underneath. ‘The limestone was reached,
between seven and eight feet below the surface. It was in thin
irregular beds, separated by incohering sand and calcareous
grains, similar to the mixture which composes the rock; its total
thickness is about six feet; the organic remains are the same
which characterize the limestone at Vincentown.

The limestone belt measured from northwest to southeast,
appears as far as exposed to be about one mile wide, and there
are pretty good reasons for concluding that it expands still more
to the southeast.

Vincentown.—The thin limestone stratum of the vicinity of
Vincentown extends to the northeast, as far as Benjamin Pea-
cock’s, on the road between Vincentown and Pemberton, and
one mile from the limekiln, on the south branch of the Rancocus.
To the southwest it extends between Vincentown and Medford,
and is seen on the farm of James Lippincott. It occurs at
Hosea Moore’s, on the Red Lion road, three and a half miles
from Lumberton.

I do not think it at all established that Benjamin Peacock’s is
the extreme northeastern limit of this formation, for there is a
thin band of calcareous rock in the marl bank at New Egypt,
which is almost identical in character with the rock at the lime-
kiln on the Rancocus; and what is remarkable, the top bed at
Egypt is identical with the top or overlying bed at the limekiln,
being a thin layer of a brownish siliceous sand, tinged here and
there with green. This would extend the limits of the limestone
much towards the northeast. On the Rancocus it is very thin,
consisting of two layers, each only six or eight inches thick,
and separated by eighteen inches of sand. It overlies the marl,
as we know the corresponding stratum does in Mannington,
Salem county.

224

Analysis of the Yellow Limestone, from the neighbourhood of
Eayrstown, Burlington County.

Lime, - - - - 49-69
Carbonic acid, 2 : 38:31
Silica and other impurities, 9-00
Water, - - - 2 3:00

100-00

It is in many places a very pure limestone, containing ninety
per cent. of carbonate of lime. It has a structure somewhat
resembling certain varieties of the oolite of Europe, imparting to it
a granular and sandy aspect, which might lead the careless ob-
server to regard it as a more impure limestone than it is.

SECTION IV.

Ferruginous Yellow Sand—Formation IV. Brown Sandstone and
Conglomerate—Formation V.

Geographical Range and Extent of the Yellow Ferruginous
Sand.—This formation cccurs immediately above the greensand,
unless where the thin fossiliferous limestone intervenes, and
directly beneath the brown sandstone. Its position is usually at
the base and in the sides of the outlying hills capped by the sand-
stone, and it probably spreads extensively to the southeast of the
marl region in the district called “ the pines.”

Geographical Extent and Composition of the Brown Sandstone.—
The circumstances under which this stratum occurs, have in the
general way been already mentioned. The brown sandstone is
found high upon the sides, or crowning the tops of all the insu-
lated hills scattered over this district of the State ; it lies in masses
of all dimensions, from considerable blocks to pebbles the size of
gravel, strewing the adjacent portions of the plain, and constituting
in fact, in its disintegrated state, an essential part of the surface
matter of the district. Being the only native material of the
nature of building stone, known or employed throughout the
lower section of the State, it becomes a matter of interest to

225

ascertain and trace its numerous detached beds, so as to repre-
sent their place and extent upon the map. It is obvious that the
topography of the map of the State is not sufficiently minute for
such a purpose; and it is equally manifest, that the task, however
useful, would far exceed the scope and time allotted to this
general survey. Though I am not able therefore to specify all
the localities of this rock, which indeed are very numerous, it
may be useful to mention that the higher the ground the more
likely we are to find it in mass, and that it is by no means con.
fined to the distinctly formed hills, but occurs extensively in the
more elevated parts of the intermediate country. We may state,
moreover, that the larger and more angular are the loose frag-
ments scattered around, the greater is the probability, that the
rock exists in a solid stratum near at hand. The rock consists
of two varieties, the one a coarse sandstone, the grains of quartz
being cemented by brown oxide of iron, which colours the
whole mass; and the other a similar sandstone, containing in
addition, small white or yellowish pebbles of quartz, giving it the
character of a puddingstone. In many instances, I have found
the finer grained variety to lie beneath the other, but whether
this be a universal rule or not, I cannot say.

The most conspicuous of the detached hills containing the two
ferruginous strata before us, are:

The Nevesink range, on the southern shore of Sandy Hook
bay; the range south and southeast of Middletown; the two
isolated hills near Red Bank; those near Colt’s Neck; the Sand
Hills, between New Brunswick and Kingston; Mount Holly ;
Arney’s Mount, near Juliustown; the Evesham Mount; the hill
at the mouth of Shark river; and the Forked River Hills, near
Barnagat.

Besides these localities there are several others where the
brown sandstone, the uppermost of the series, occurs at an eleva-
tion but little exceeding that of the general surface of the district.
One of these points is about four miles from Burlington, on the
road to Mount Holly.

The ordinary condition of the yellow ferruginous sand is that
of a loose, dry, and rather coarse sand, deeply stained by the
hydrated peroxide of iron. This ingredient is sufficiently abun-
dant in some places to act as a cement to the sand, and to form

226

large masses or concretions of a singular ferruginous sandstone
of a cellular structure. These occur in many places in the cliffs
of the Highlands of Nevesink, especially af their southeast extre-
mity. In the cliffs near the mouth of the Nevesink river the
ferruginous sands contain also numerous hollow concretions
composed of the same brown mixture of sand and oxide of iron,
having the shape of bottles, flasks, and hollow balls or bombs;
and what is curious, these are full of white sand, the ferruginous
particles seeming to have been withdrawn from the sand within,
during the formation of this concretion.

The nearly uniform height at which the yellow ferruginous
sand and the overlying brown sandstone occur, wherever they
are found in the greensand region and the tract bounding it on
the northwest, leads us to infer, that these beds were once conti-
nuous over the whole area at present occupied by the lower
members of the series.

The denuding currents, which have removed so much of these
materials from the surface of the marl tract, have, in their pro-
gress towards the ocean, deposited apparently a large portion of
the looser particles, in a general diluvial covering, concealing the
strata, throughout the whole southeastern side of the southern
half of the State.

The superficial sands thus derived occupy the area generally
known as the Pines. Constituting as they do the debris of strata
remarkable for their ferruginous composition, we can readily
account for the extensive deposits of bog tron ore, which they
furnish wherever circumstances favour a sufficient infiltration of
water through them.

ORGANIC REMAINS OF THE UPPER SECONDARY STRATA.

It is of little importance to the practical purposes of the present
report, to enter into any details respecting the numerous highly
curious fossils which abound in the formations, a genera] de-
scription of which I have now given. The most fossiliferous beds
are the greensand or marl stratum and the limestone, which so
generally reposes immediately upon it. The fossils from these
deposits, together with others from some equivalent formations in
the Southern States, are described with the requisite details in an

227

interesting work devoted expressly to the subject, by Dr. 8. G.
Morton, of Philadelphia. This highly esteemed contribution to
our geology, is entitled “Synopsis of the Organic Remains of the
Cretaceous Group of the United States,”—1834.

To that source I must refer for much specific information
respecting the individual fossils of the greensand group. I may
be allowed, however, to indulge in a few generalizations calcu-
lated to impart more correct notions than commonly prevail
respecting the nature of the fossils, and the relative age and origin
of the strata in which they are imbedded.

There have been found up to the present time, in the marl and
the deposits connected with it, relics of about seventy-five extinct
species, chiefly marine; of these, at least seven are of the class
of large reptiles, including three species of crocodile; two of
fishes; a tortoise, and a wading bird; upwards of sixty-five are
remains of shell-fish, corals, and other tribes low in the scale of
organised beings. It is a curious fact, that not one of the fossils
of this catalogue can be traced to belong to any species living in
the present day ; and it is a scarcely less interesting circumstance
that between these fossils and the organic remains of the most
nearly related strata of Europe we discover but one species,
the Pecten Quinquecostatus, common to the deposits of both con-
tinents.

The first fact determines the place of the marl group to be
somewhere among the secondary rocks, and the generic affinities
of the fossils to well known fossils of the greensand and chalk
formations of Europe, makes us naturally regard that part of the
secondary series as the most probable place to which to refer
them. The striking want of identity between the species, renders
it, however, a question of much uncertainty, to what precise for-
mation of the secondary series of Europe these deposits strictly
correspond.

To refer the production of the marl strata of New Jersey to
the same period which produced the greensand rocks of Europe,
merely in consequence of their both containing the green granu-
lar mineral, and to their having, moreover, a general resemblance
in their fossils, is to commit the decision of the question to far too
loose a mode of reasoning. Received principles of geological
investigation require us rather to consider our own deposits as

228

having originated during a somewhat different epoch from that
which produced the European greensand formation.

The following list embraces nearly all the organic remains of
the upper secondary series, hitherto discovered in New Jersey.
It is compiled principally from the synopsis of Dr. Morton.

ORGANIC REMAINS OF THE GREENSAND FORMATION.

RepTILEs.

Mosasaurus.—Teeth, vertebra, and bones of the extremities of
this large massive saurian, have been found at various points in
the greensand tract, in the excavations made for marl. ‘They
are thought to be identical with those of the Mosasaurus of
Europe.

Geosaurus.—Teeth, with a portion of the jaw.

Crocodile-—Teeth and other portions, indicating three species,
occur in the greensand.

Saurodon, (Hays).—Portions of a jaw of an extinct animal; the
relations of which are not very clearly known. It is thought
to be analogous to the saurians.

Great saurian, (of Honfleur).—I have discovered two vertebre in
the greensand near Big Timber creek, which I regard as either
identical with, or very closely allied to bones figured by Cuvier
from Honfleur, which he considers to approach nearer to the
plesiosaurus than to any other genus.

Testudo.—Several bones of a large species of the order Testudo.

Coprolites.—These bodies have been occasionally met with, espe-
cially in the neighbourhood of Crosswick’s creek, near the top
of the stratum. In the present instance, they are most probably
the fossilized dung of a species of crocodile ; some of the bones
and teeth of which occur near them.

FisHes.

Squalus.—Teeth and vertebrae of several species, considered for-
merly to belong to the genus Squalus, but lately placed by
Agassiz under genera only more or less allied to the shark, are
abundant in nearly every part of the greensand formation.

Sphyrcena.—Part of a jaw and several teeth of this curious
genus of fishes have been found in the greensand, in Monmouth
county.

229

Birps. ;
Scalopax (Snipe).—A solitary tibia, apparently belonging to this
genus, has been found in the greensand, near Arneytown.

TESTACEA.

Sepia.—Several remains supposed to be of this genus.
Nautilus Dekayi, (MM)
Belemmites Americanus, (M.)
Ambiguous, (M.)
Ammonites placenta, (Dekay.)
Delawarensis, (M.)—Chesapeake and Delaware canal.
Vanuxemi, (V.)—Chesapeake and Delaware canal.
Scaphites hippocrepis.
reniformis, (AL)
Baculites ovatus, (Say.)
Bulla lignaria?
Turritella vertebroides, (M.)
encrinoides.
Rostellaria arenarum, (Jf)
undetermined, (M.)—Casts, Delaware.
Tornitella bullata, (M.)
A small species ; casts only found.
Cyprza.—A solitary cast, Delaware.
Patella tentorium, (M.)—Arneytown.
Ostrea falcata, (M.)—An abundant fossil.
plumosa, (M.)—Arneytown.
panda, (M.)—Delaware.
torosa, (M.)—Mullica Hill.
Gryphea convexa, (M.)
matabilis, (.)
vomer, (M.)
Exogyra costata, (Say.)
Pecten quinquecostatus, (Sowerby.)
craticula, (f.)—Arneytown.
venustus, (V.)
Plagiostoma gregaie, (JV.)—Burlington county.
pelagicum, (J)
Anomia argentaria, (M.)—Delaware.
tellinoides, (M.)
20

230

Placuna scabra, (JZ)
Plicatula urticosa, (JZ)
Avicula laripes, (JZ)

A cast; species undetermined, (JZ)
Pinna.—Two species not determined, (JZ)
Pectunculus.—Species undetermined, (JZ)
Cucullzea vulgaris, (1)

antrosa, (JZ)

Nucula.—Small casts of an unknown species, (J)
Trigonia thoracica, (JZ)
Cardium.—Apparently two species.
Cardita? decisa, (M/.)\—Delaware.
Crassatella vadosa, (7)

tellini, (J) :
Venilia Conradi, (14)—Arneytown.
Cytherea excavata, (Z)—Arneytown.
Lutraria ?
Pholodomya occidentalis, (14.)—Delaware.
Pholas cithara, (JZ.)—Monmouth county.
Teredo tibialis, (J)
Clavagella armata, (Z)—Arneytown.
‘Terebratula Harlani, (4Z.)—New Egypt.

fragilis, (Z.)—New Egypt.

Sayi, (14)—Burlington county.
Serpula barbata, (14)—Deal, Monmouth county.
Hamulus onyx, (J)

CrusTAcka.

Astacus.—A small species, Delaware.
Cancer.—Fragments of several distinct species have been found.

EcuINoDERMATA.
Clypeaster florealis, (1Z.)—Delaware.
geometricus, (14)—Delaware.
Spatangus ungula, (J7)—Delaware.
Turbinolia inauris, (JZ)

LOCAL DETAILS OF THE GEOLOGY OF THE MARL REGION.

With a view to exhibit the various aspects which the greensand
assumes in different neighbourhoods, and to bring forward many

231

matters of local interest not appropriate in a general account of
the formation, I shall here introduce a series of descriptions
embracing the principal localities where the marl is at present
excavated.

Pursuing the usual order adopted, in tracing the local features
of the other formations of the State, that is to say, proceeding
from the northeast towards the southwest, I shall commence with
the township of Middlesex, in Monmouth county.

Middletown Point.—The lowest portion of the greensand stra-
tum, where it passes into the underlying blue sandy clay, is exposed
at several places in the vicinity of Middletown Point, which is a
little outside of the boundary designated as the northwestern edge
of the formation. The proportion of the green granular mineral
in the marl of this neighbourhood, is, therefore, less than where
the higher layers of the greensand are most developed, towards
the southeast.

On the farm of Mr. William Little, not far from Middletown
Point, the stratum is of a light ash-gray colour, inclining some-
what to greenish. Though it contains a large excess of clayey
matter, the green granules are readily discoverable. These
particles after separation from the marl by washing, are of a
light clear green.

The composition of this marl is, in 100 parts:

Greensand, - - - 46-73
Clay, - - - - 53:27
Quartzose sand, - - none.

100:00

Assuming the proportion of the potash in the green grains to be
11°5 per cent., which is the mean of the fifteen systematic ana-
lyses given in a preceding chapter, we find the amount of the
alkali in this marl to be 7-47 per cent., a quantity capable of
imparting very decided fertilizing effects.

Mount Pleasant.—One of the most northern points where the
stratum is dug for marl, is upon a farm of J. Morgan, near Mount
Pleasant. In the same neighbourhood a marl of very similar
quality, is found underlying a part of the farm of Mr. Castle-
reagh, near the northwestern base of the belt of hills lying south

232

of Middletown. ‘These localities being near the northwestern
margin of the formation, where only the lower portion of the
greensand, adjacent to the underlying blue clay exists, the material
contains, as in nearly every similar locality, but a moderate pro-
portion of the green granular mineral, in which, as we conceive,
the chief fertilizing power resides.

The hills here referred to, terminating on the farm of Mr.
Conover, near the Dutch Church, consist of the ferruginous
yellow sands, immediately overlying the greensand, overlaid by
the brown ferruginous conglomerate which constitutes their sum-
mits. Greensand, therefore, occurs in places, beneath these hills
and around their base. It is generally replete in the green
mineral, and is of excellent quality, having been used in the
neighbourhood since the first discovery of its fertilizing effects.

At Conover’s, near the Dutch Church, we are in the midst of a
highly fertile marl tract. The country is rather flat, or gently
undulating, and extensively intersected by shallow valleys of de-
nudation, or by meadows which are furrowed out down to the
marl stratum, and in some cases twelve feet into it.

Analysis of the Marl, from the farm of Jacob Conover, Freehold
township, Monmouth county.

Composition.—In 100 parts:

Greensand, - - - 85
Clay, - - - ~ lI
Quartzose sand, - = = 4

100

The amount of potash which this mar] contains, deducing it
from that of the greensand, is 9°7 per cent.

The soil is mostly a loamy clay, sometimes sandy, and not
often more than thirty feet above the top of the marl. Upon the
marl lies a sandy stratum, containing a trifling share of the green
particles and much ferruginous matter, which in some cases, by
filtering down, has produced a change on the upper part of the
marl bed to the depth of a few feet, dissolving out the shells and
replacing them by oxide of iron. ‘The thickness of the marl bed
is not known, but perforations twenty feet deep have not pene-
trated through it. Its general aspect when moist is a deep blue,

233

or black ; when dry a light blue, or gray. The lighter kind con-
tains more clay, which is of a dove-colour, and sometimes of a
light gray. The tint of the grains is a dark olive-green, almost
black, and in this quarter rarely a light green. Sometimes the
clay exceeds in quantity the green grains, and this in marls which
are regarded as being very active. Those varieties which
possess the lowest reputation are found invariably to contain
either a quantity of siliceous sand or mica.

The fossils are Exogyra costata, Gryphea convexa, G. muta-
bilis, Ostrea falcata, Belemnites Americanus, Terebratula, Spines
of Cidaris, Teeth of Shark, and Vertebrze of Crocodile.

When the mar! dries, the surface is sometimes covered with a
white or gray incrustation. When moist, the black marl often
exhales a sulphurous odour, and the white efflorescence has an
astringent sweetish taste, indicating it to be in part at least, a
sulphate of alumina.

The marl in this quarter has been known and used as a fer-
tilizing agent for forty years. It is applied very profusely ; one
hundred loads to the acre, or even more, being no unusual
dressing. The improvement to the soil is very permanent, chang-
ing the natural growth from Indian grass and five finger, (or
cinquefoil,) to fine white clover. White alder and other plants
of rich soils abound in the meadows.

The natural timber of this, as of most other parts of the marl
tract, consists of several varieties of Oak, also Chestnut, Locust, -
Beech, Maple, Dogwood, Hickory, Liriodendron or Tulip Pop-
lar, &c.

The following analyses exhibit the composition of the marl in
this vicinity :

Analysis of a Marl, (the upper stratum,) from the farm of John
Smock, Freehold township, Monmouth county.

Composition.—In 100 parts:

Greensand, - - - 90-00
Coarse siliceous sand, - 2:00
Ash-coloured clay, - - 8:00

100-00

20*

234

Analysis of the Greensand.

Composition.—In 100 parts:

Silica, "= - - . 51:00
Protox. Iron, - - - 25:10
Alumina, - - - 7°50
Potash, - - - - 9:30
Lime, - - - - "(a trace.
Water, - - - - 6:50

99-40

Marl from the farm of Dr. Conover Thompson, two and a half miles
northwest of Freehold, on the head waters of South river.

Description.—Colour, light-gray, with a very little tinge of green;
is adhesive, and has much the character of clay.
Composition.—In 100 parts :

Greensand, - - - 50
Clay, - - - - 40
Quartzose sand, - - - 10

100

The proportion of potash in this marl, deduced from that in the
greensand, is 5°7 per cent.

Marl from the farm of William T. Sutpham, on the head branches
of South river, two and a half miles northwest of Freehold.

Description.—Colour, earthy-gray, with but little tinge of green,
mottled and coloured with oxide of iron.
Composition.—In 100 parts:

Greensand, - : - 40
Clay, . = - : 52
Quartzose, - - - - 8

100

The potash in this marl, deduced from that of the greensand, is
4°6 per cent.

Mr. Joseph Vandeveer has opened pretty extensive pits, about
half a mile to the north and west of Bucks. The marl is much

235

like that of Mr. Smock’s. The following analyses will show the
composition in 100 parts, of the upper and lower strata, the last of
which is the best.

Upper stratum :

Greensand, - - - 70
Clay, - - - - 27
Quartzose sand, - - - g

100

Lower stratum :

Greensand, - - - - 92
Clay,. - - E = 5
Quartzcse sand, - - - 3

100

The amount of potash, as deduced from that of the greensand,
is, in the upper bed, 8 per cent., in the lower 10°5. The washed
grains of the above marl are of a rich green, and small in size.

Large excavations have been made to the north and east of
Bucks, by Mr. Charles Hendrickson, and a marl obtained cor-
responding in character to the preceding.

The above specimens furnish fair examples of the character of
the marl in the vicinity of Swimming river.

Few exposures of marl are noticed in the tract between Bucks
and Bloomdel. One and a half miles west from the latter place,
it has been quite extensively worked by Elisha Holmes and Mr.
Ely. A specimen taken at a point one-fourth of a mile from
Bloomdel, where the road approaches to the side of Swimming
river, will furnish an example of the marl of this neighbourhocd.

This marl is greenish-brown in colour, and somewhat argilla-
ceous in texture. When washed, its granules become more dis-
tinctly green, they are of small dimensions.

Composition.—In 100 parts:

Greensand, - - - 83
Clay, - - - - 13
Quartzose sand, - = - 04

100

By direct analysis, this marl yields 8:5 per cent. potash.

236

At Ely’s mill the marl is very impure, being almost entirely
composed of siliceous sand; and doubts may exist whether it
belongs to the marl bed, or the overlying clay.

At Mr. John Johnson’s, Vut Swamp, the marl consists, towards
the top, of the usual ferruginous yellow clayey bed, containing a
small portion of the dark grains. This is not used, but is pared
off to a depth of two or three feet. Next to this comes the dark
marl, nearly black when wet, and rather hard in the bed, from
the quantity of ferruginous matter which cements it. It crumbles
on exposure, and becomes gray or even white, from the efflores-
cence which collects upon it. In it are large roundish masses of
the marl cemented into firm stone by the oxide of iron. These,
however, crumble down in time by exposure. In these beds the
siliceous sand is very little in quantity. The top of the bed is the
richest in greensand; lower down there is more of the dove-
coloured clay, resembling precisely the clayey marl at Conover’s.
The vertebrze of a species of crocodile have been found here.

On Porricy brook, upon the road to Middletown, there occurs
a fine exposure of the marl. It seems to be very thick and is
covered by the yellow ferruginous sandy marl which is seen
again half a mile south of Middletown, in the meadows. The
black marl lies beneath.

At Middletown and its immediate vicinity, the upper yellowish,
or ferruginous bed is chiefly seen; while the greensand marl has
been reached in only a few points, though there can be no doubt
of its existence at a small depth every where in the neighbour-
hood.

This upper portion of the marl] stratum contains a considerable
amount of the green grains, but mixed with much ferruginous clay
and sand of an orange and variegated yellow hue. This orange
and many-coloured clay is distributed in streaks and blotches.

The upper stratum is inferior to the green marl in fertilizing
power, though it is used with excellent effect in many places near
Middletown.

Marl from the Farm of Captain Edward Taylor, at Middletown.

Description.—Colour dull green; texture clayey, grains of
small size. After being washed and freed from clay, the colour
is more distinctly green. |

237

Composition.—In 100 parts.

Greensand, - : z 80
Clay, - - - - 14
Quartzose sand, - - 6

100

The proportion of the potash, ascertained by direct experiment,
is 8 per cent.

The marl from the lower portion of the bed at Captain Taylor’s,
is richer in greensand than that from the upper, as will be seen
by the following analysis:

Composition.—In 100 parts:

Greensand, - = - 90
Clay, ~ J = : 5
Quartzose sand, - - 5

100

The amount of potash which it contains, is 9.9 per cent.

Between Middletown and Chapel, Jonathan Tunis has pene-
trated into the lower greensand marl, and uses it in preference to
the yellow top bed, and with great advantage to the crop.

Near to Chapel, and about two miles east of Middletown,
Mr. Daniel G. Conover, after penetrating the overlying soil
and ferruginous layer, has obtained a marl of a singular
mottled appearance ; consisting of a mixture of light-coloured
clay and greensand, looking when freshly cut somewhat like
a decomposing granite. The lower portion of this marl has
for its

Composition.—In 100 parts:

Greensand, - - - 84
Clay, - . - - 10
Quartzose sand, - - 6

100

The proportion of potash deduced from that of the greensand,
is 9°6 per cent.

238

The colour of the green mineral, after washing, is but little
changed.

The upper portion of the mar] bed of Mr. Conover is less valu-
able in greensand, as will be seen by the following analysis :

Composition.—In 100 parts:

Greensand, - : é 67
Clay, - - - - 30
Quartzose sand, - - 3

100

The amount of potash which it contains, is 7°3 per cent.

Chapel is upon a flat hill or table land; and a well near this
place dug seventy-four feet through the upper strata, did not reach
the marl, though it shows itself, near the surface, in all the sur-
rounding low grounds, where it is of very good quality.

The hills are sandy and strewed with fragments of the con-
glomerate, which is also in place, being quarried half a mile
south of Chapel.

The timber growth on the hills contains a pretty large mixture
of cedar.

The marl extends from Chapel north towards the Bay shore,
as far as the permanent land itself. Richard Wallin has reached
it in digging a well; it was seven feet below the surface, and was
penetrated fourteen feet. Mr. Anderson, within half a mile of
the shore, also has a marl pit. The dark green grains abound in
the sands of the beach, and every where as we pass along the
road from Chapel to the Bay shore, towards the east.

Bay Shore and Cliffs of Nevesink Hills.—The marl appears to
extend to within a short distance of the Bay shore near Compton
creek. The first cliffs which we meet with on going along the
shore to the east, exhibit a dark stratum, chiefly clay and siliceous
sand, with mica, containing very little of the marl, and often a
considerable share of copperas, which shows itself upon the sur-
face, in the state of a yellow efflorescence. Tracing the base of
the cliffs, we see this stratum slowly rising and forming the lowest
bed visible along the beach, nearly the whole way to the termina-
tion of the highlands at the Telegraph hill.

In some places the cliffs have a height of fifty or sixty feet,

239

composed of several different beds, all containing more or less of
the marl; but some of the layers are chiefly made up of siliceous
sand, and clay, and ferruginous matter. Over the dark lead-co-
loured siliceous clay, a stratum of the sand is seen, often green,
though for the most part gray and quartzose. High above this
the true marl is seen in many places, and may be known by its
white efflorescence.

The marl taken from the cliffs about two miles northwest of
the Telegraph Tavern, exhibits the following,

Composition.—In 100 parts:

Greensand, - - - 92:2
Clay, - - - - 58
Quartzose sand, - - 2:0

100

The proportion of potash, deduced from that of the greensand,
is 10°6 per cent. The appearance of this marl is a dull or dirty
green, and is little changed by washing.

Where the cliffs are high, the conglomerate is seen in its natu-
ral place, over the top of all. Near the upper surface of the
marl bed may be seen large globular masses of indurated and
cemented marl, like that found beforeat Nut Swamp. They here
possess the hardness of a true rock and do not crumble. The
freshly fractured surface is often very beautiful, showing the
green grains of marl distributed through a cement of argillaceous
red oxide of iron. The globular masses are seen in horizontal
layers in the marl, and they strew the beach pretty thickly. The
blocks of the horizontal iron stone are often several feet in
diameter. Sometimes the consolidated ferruginous masses of the
cemented sand are the size of a small apartment.

In several places beneath these cliffs of the Highlands, vast
masses of the strata have subsided by the undermining action of
the water passing through the lower beds, and they form an
under-cliff or landslip with a steep pitch toward the land, bringing
down into nearer view the top strata, the upper ferruginous sands
of which, owing to the condition of their oxide of iron, are of a
most beautiful reddish colour. 5

At the shore beneath the Telegraph hill on the ocean side, the

240

lower dark astringent stratum is seen at the water’s edge, the
piles in the foundation of the wharf, in front of the Telegraph
Tavern being driven into it. Some portion of this bed is said to
be marl, and the green grains abound every where among the
sands of the beach, as they do at Long Branch, a few miles more
to the south, and indeed the whole way from the commencement
of the Nevesinks along the bay shore, and along the sea-shore
to Deal.

Tracing the cliffs round the Telegraph Point to the mouth of
the Nevesink river, the lower or marl-bearing strata, are covered
by a steep talus or inclined bank of fallen matter at the base of
the cliff, reaching thirty or forty feet up. Above, are the yellow
sands covered by a layer of the cellular iron stone several feet in
thickness, being beautifully displaved at the Devil’s Chimney.
Above this there is a very ferruginous, brownish, consolidated
sandstone, full of impressions or casts of shells, especially ostrea
falcata. It seems to be a more ferruginous portion of the stratum.
A little above this, at the height of eighty or ninety feet, is a bed
a few feet thick, of a bright green clay, consisting apparently of
the same material as the light green variety of the marl, but not
in a granular condition ; it includes a few indistinct light green
grains. Over this again and towards the top of the hill, the frag-
ments of the conglomerate abound, and there is every reason to
believe that all the hills near the mouth of Nevesink river, are
capped by the conglomerate in place.

Along the north bank of the Nevesink river, at Mr. Harts-
horn’s, the stratum which is on a level with the beach is the
copperas-bearing dark clay and sand. It has been found by him
to be hurtful to the soil when applied thick, but as it contains a
very considerable share of the green grains, it is probable that
applied in lighter dressings, it might prove somewhat beneficial.

There is no good marl from the mouth of Nevesink river up as
high as Claypit creek, above which as far as its head, the marl
extends on the north side and is generally very good. The other
or astringent stratum below the marl, sometimes takes its place
in the banks on the water’s edge.

Ascending the Nevesink river, no good marl occurs below the
west side of Burgis’s or Claypit creek, where it is of excellent
quality; from thence to the next, or Redneck creek, the impure

241

astringent kind prevails; on the west of the creek, the bed at the
water’s edge is again the true marl, being like Burgis’s. The
deleterious bed contains much ordinary sand and mica, abounding
also in oxide and sulphuret of iron, and seems to be in fact the
same stratum as that upon the bay shore under the Greenland
banks, in the Nevesinks.

We may trace the marl to Crow’s creek ; approaching which
it becomes very green and good. Here and farther east it lies
below the layer of nodular indurated marl seen on the bay shore,
on the top of which is the micaceous sandy bed containing cop-
peras. In one place on the very beach, the marl has been dug
and exported to Barnegat, for sixty-eight cents for the load of
twenty bushels.

On drying this marl, it assumes a light-green colour. The
spurious bed almost invariably presents the yellow astringent
efllorescence, and is evidently a different layer from the good
marl; and there seems to be no good reason to doubt that this
shore if examined, would every where display both beds; the as-
tringent clay above, the nodules next, and below all, the pure
greensand marl.

The reason that the banks of the Nevesink river display some-
times the true marl, and at others the dark astringent clay, seems
to be, that there occurs a slight undulation of the strata. Some
have thought them portions of the same stratum, shading into
each other upon the same level. ‘The above view is the correct
one, and is important, as it indicates the possibility of reaching
marl almost any where by sinking to a very small depth.

Red Bank.—In this neighbourhood the banks of the river vary
in elevation from ten to twenty feet and upwards. On the north
side, near the bridge, on the land of Mr. Tylee Conover, the
bank presents a bed of diluvium four feet thick, the lower part of
which is tinged with oxide of iron. Beneath this lies the upper
layer of the marl, eight feet in thickness, consisting of a mixture
of very tenacious clay and greensand. Resting directly below
this, and nearly on a level with the tide, occurs the main bed of
marl, forming the beach of the river. It is composed almost
entirely of the greensand, the extraneous matter being merely a
little white siliceous sand and clay. Excavations to the depth of
several feet are made at the retiring of the tide, and the marl

21

242

thus procured is much preferred to that of the overlying layer in
the bank. Its colour is a dirty green; that of the washed green-
sand is brighter; the granules are rather larger.
That portion of the stratum which is below the level of high
water at Mr. Tylee Conover’s, gives the following:

Composition.—In 100 parts:

Greensand, - - - 93°85
Clay, - - - - 6°15
Quartzose sand, - - none.

100-00

The amount of potash in the whole marl, as obtained by direct
analysis, is 9.5 per cent. Though the marl throughout this
neighbourhood is generally rich in the greensand, the good effects
of this are sometimes impaired by the presence of decomposing
sulphuret of iron, which it derives especially from the overlying
ferruginous bed.

At Judge Patterson’s we have a convincing proof of the hurt.
ful influence of the copperas, in a marl otherwise excellent; his
being extremely rich in the fertilizing green grains. The bank
for a few feet up from the level of the water, is composed of the
marl stratum, abounding in the yellow astringent efflorescence.
Tried upon the land, it has been found injurious to the crops for
at least the first year or two, unless when applied in great
moderation.

Where the poisonous impurity is abundant, it is not safe to
employ more than five loads of the marl upon an acre; nor do I
see any good reason why five loads of a rich marl is not enough,
in nearly all cases, for a single dressing.

The entire material of the beach beneath the bank, consists of
the dark greensand, from which nearly the whole of the astrin-
gent matter appears to be removed by the washing of the waves,
as the caving of the bank from time to time, brings down the
matter upon the beach, and within the dissolving action of the
water.

This washed marl is pure, and may be used, as some experi-
ments made by Judge Patterson have fairly proved, in any pro-
portion, even at the rate of one or two hundred loads to the acre,

243

without showing any caustic action upon the vegetation. This
among other facts induces me to recommend to the farmers, to
expose their caustic or astringent marls to the rain for a season,
before attempting to employ them.

On the south side of the river, one-fourth of a mile below Red
Bank, the shore, which is rather steep and about twenty-five feet
high, displays a bed of dark micaceous sandy clay, overlaid by a
mass of diluvial sand and gravel twelve feet in thickness—the
line of separation between these being very obvious. The dark
micaceous clay and sand on this side of the river seems to replace
the upper impure layer of marl of the opposite or north shore.
From the surface of the water to its upper edge it is about twelve
feet in thickness, and it extends down along the water’s side as
far as Jeffries’ Point.

The stratum of pure greensand lying immediately below this
layer, corresponds to the lower bed on the north side of the river.
It consists almost entirely of the green granules. The marl is
penetrated to the depth of about twenty feet at several spots
along the beach. Though Jeffries’ Point seems to be the termi-
nation of the dark micaceous clay and the underlying greensand
on the south side of the river, yet there are good reasons for
inferring that the marl extends along the opposite side at an
accessible level the whole way to the extremity of the peninsula
dividing the Nevesink and Shrewsbury rivers.

The marl at Jeffries’ Point is of a lighter green than any in
this immediate quarter. Very few organic remains occur in the
greensand formation in this vicinity, either in the cliffs of the
Nevesink Hills or in the banks of the river.

The marl of Jeffries’ Point gives by analysis the following:

Composition.—In 100 parts:

Greensand, - - = 2 92:5
Clay, - - - - v5)
Quartzose sand, - - none.

100-0

The proportion of potash in this marl, deduced from the
average quantity in the greensand, is 10 per cent.
When washed, the granules are large and of a dark green colour.

244

A marl taken from the beach near Red Bank, belonging to
Jonathan M’Lane, exhibited the following

Composition.—In 100 parts:

Greensand, - - - 91°4
Clay, -- - - - 86
Quartzose sand, - - ‘none.
100-0
The potash in this marl, by calculation, is very nearly 10

per cent.
The ordinary aspect of the marl is a dull green; that of the

washed greensand is a brighter, purer green. The granules are
rather large.

Marl of good quality displays itself in several places between
Red Bank and Shrewsbury, and around Eatontown. That at
the farm of Mr. Lafetrea near Katontown affords by analysis the
following

Composition.—In 100 parts:

Greensand, = - = 79
Clay, - : - - 13

Quartzose sand, - -

100

The potash in this marl, by estimation from the amount of the
greensand, is 9.1 per cent.

About one mile southeast of Eatontown, in a low swampy tract
of ground, Dr. John P. Lewis has uncovered a stratum of some-
what peculiar marl, composed of fragmentary shells, a little
greensand, and much quartzose sand intermixed. From several
trials which have been made, it would appear to be endowed
with decidedly fertilizing properties.

Between Eatontown and Long Branch, and about three miles
from the sea-shore and two from Eatontown, at a mill called
Turtle Mill, there occurs a variety of marl somewhat analogous
to the above. It consists of hardly any thing but shells in a
fragmentary condition, very friable and purely calcareous, and
contains but a very small share of the green particles; its colo ur

245

is yellowish, owing to a small portion of common sand. The
shells are in a very broken»condition, but we may recognise
them to belong to the well known secondary fossils of the marl.
The large shell called Terebratula Harlani seems to constitute a
large portion of the mass. Something similar is seen farther to
the south, on the farm of Mr. Field, about one and a half miles
from Eatontown. This deposit deserves to be traced more mi-
nutely, as it is probably a new variety of mar! fit for the agricul-
ture of. the neighbourhood, containing much more lime than the
greensand formation usually possesses.

Long Branch.—Along the cliffs facing the ocean in front of the
boarding-houses at Long Branch, appearances in several places
show that the true marl stratum meets the sea-coast in this
quarter, and that it cannot lie at any considerable depth below
the beach. About half a mile north of Renshaw’s, at apparently
the highest point in the cliff, the astringent clay bed which so ge-
nerally accompanies the marl as an overlying stratum is exposed,
rising four or five feet above the average level of the beach. This
itself is strongly indicative of the existence of the marl at no great
distance beneath. The probability of this is manifested, how-
ever, in another way. ‘The sand of the beach contains a very
notable proportion, often five per cent. or more, of the green
granules, of the marl, which examination assures me cannot be
derived from any of the strata in this part of the bank, and which
therefore, can only come from a bed extending into the sea below
the ocean level, or at least lying as low as the base of the cliff.
This mixture of the green granules among the sand of the beach
is observable along the whole of the bay shore, from near Chapel
to the Telegraph Hill, and thence along the ocean side from the
mouth of the Shrewsbury river past Long Branch to Deal, and
somewhat further. It has been discovered somewhat recently,
that the beach sand throughout this line is endowed with active
fertilizing powers, attributed heretofore to salt and other supposed
marine substances in the beach. But the well known properties
of the green grains, coupled with the fact that in every place
along the shore further south than Deal, where the marl does not
reach the coast, the sand of the beach contains none of the dark
granules, prove conclusively that the benefits so distinctly per-
ceived, are attributable to the source which I suppose. The good

21*

246

effects of the beach sand are strikingly exhibited upon Wardell’s
farm, a little north of Long Branch: no less decided results are
also witnessed on the farm of Jacob Curlis, at Deal.. The most
sterile patches of sandy soil are made to yield very abundant
crops of corn by the use of this powerful agent. The quantity
of the beach sand applied, is often as great as two hundred loads
to the acre; but the facilities for procuring and spreading it are
very great. It is obviously a point of importance to discover
those portions of the beach where the green matter is most abun-
dant; for there are spots which are much darker than the rest from
this cause. Experience has already taught that the sand gathered
afier the heavy storms of the winter, is the most efficient, a fact
countenancing the notion that the green grains are cast up by the
beating of the surf. The high degree of fertilizing power pos-
sessed by the beach sand, upon both the clayey and dry sandy
soils of this portion of the sea-board, goes far towards establish-
ing several very essential points in the doctrine previously ad-
vanced concerning the cause of the enriching qualities of the
greensand. It clearly demonstrates, in the first place, that the
efficacy of the marl lies mainly in these green granules, and not,
as many imagine, in the shells and other foreign substances dis-
covered occasionally in the bed. It moreover decides the point,
that the more essential and permanent. properties of this mineral
are in no way connected with the gypsum, or with the carbonate
of lime, which so frequently form a coating upon the green grains.
Both of these incrusting matters, should they exist in the stratum
from which the granules are derived, are too easily dissolved by
the water which incessantly washes the shore, to remain in the
sand in the smallest appreciable quantity.

We are torced, therefore, to ascribe the usefulness of the green
mineral to its potash, the only ingredient of an alkaline action
which is always present and which is essential to its composition.

Another important consideration is, that the marl or green
mincral loses nothing of its potency by a long exposure, even of
years, to water and the atmosphere; in other words, that it is not
dissolved, or decomposed, or changed, by the ordinary atmosphe-
ric agents which react so powerfully upon many other minerals.
We are to regard it, therefore, as nearly unchangeable until the
roots of the plants come in contact with it, cause its decomposi-

247

tion, and by the vital powers of their organs, imbibe a portion of
some of its constituents.

When we behold a luxuriant harvest, gathered from fields in
which the original soil is of a kind least of all congenial to vege-
tation; when we find that all this feriility, contrasting so strikingly
with the barrenness around it, proceeds from a few granules of
a substance sparsely distributed through the enormous and coun-
teracting excess of sea-beach sand, more arid than the soil to
which it is applied, are we not led to look with admiration on the
potent properties of this curiously constituted mineral? The deve-
lopements of geology are full of instances like this, showing in
how many unlooked-for ways, the mineral world may be made
subservient to the good of mankind.

- This striking proof of the fertilizing power of the marl ought
to encourage those districts not directly within the tract, where
some of the strata possess the green granules in a sensible pro-
portion. It expands most materially the limits of the territory
where marling may be attempted, and points us to many beds as
fertilizing, which otherwise would be deemed wholly inefficacious.

There can be no doubt that the agriculture of our seaboard
States is destined to derive essential benefit from the remarkably
wide distribution-of this green granular mineral under various
geological relationships, besides those in which it presents itself
in New Jersey.

Thus the tertiary shell marls of Delaware, Maryland, and Vir-
ginia, and I might add of other States still farther south, contain
not unfrequently as high a per centage of the greensand, as does
the sea-beach sand upon the coast of Monmouth county in New
Jersey; and I may mention that my brother, Professor William
B. Rogers, of the University of Virginia, charged with the geolo-
gical survey of that State, has already done important service to
the agriculture of some districts, by discovering, and calling at-
tention to the existence of the greensand in the tertiary strata of
Virginia.

Between Long Branch and Deal, the marl stratum has been
penetrated thirty feet. The upper two feet consist of a green
clay, seemingly derived from the disintegration of the green
grains, intermixed with a large proportion of yellowish white
clay. The main marl bed having a thickness of about twenty-
six feet, contains several subordinate layers, but all contain a

248

large share of the green granules. Beneath the whole there is a
gray-yellowish clay, in which the grains abound; they are remark-
ably large, and are associated with numerous casts of shells. A
similar layer is seen in Jacob Curlis’s pits, where it contains beau-
tiful casts of the nautilus and several univalve shells, and also
shark’s teeth. The marl stratum, composed of nearly the same
layer, is exposed again between Jacob Curlis’s and the Whale
Pond Mill, at John Curlis’s. At all these points, the bed contains
a considerable share of astringent matter, sulphate of iron, which,
wherever it shows itself in excess, may be counteracted by fol-
lowing the suggestions proposed in this report.

Elisha West’s,. near Long Branch.—A very interesting and
rather extensive exposure of the marl stratum may be seen on
the farm of Elisha West, about one mile south of the boarding-
houses at Long Branch, and in a direct line, not more than a
fourth of a mile from the sea. The pit is dry, a rather unusual
circumstance, and occurs near the head of a gently sloping
hollow or small valley, which circumstance in connexion with
the obvious outline of the ground between it and the shore, leads
the observer to believe that the top of the stratum is not as low,
by several feet, as the sea-beach. It follows, if this be correct,
either that the marl bed runs horizontally and:meets the cliffs at
the sea-side, above their base, where the inclined pile of fallen
matter may conceal it, or else that it descends with a gentle
eastward dip until it merges beneath the ocean at a lower level
than the tide. This question is of some consequence to the neigh-
bourhood, for a good marl pit opened directly on the shore would
benefit no inconsiderable line of coast.

The section in the pit is about twenty feet deep, being almost
entirely in the marl stratum. ‘The top layer, one foot thick, con-
sists of an indurated marl, somewhat similar to that at the top of
the marl at Ely’s, on Shark river. It contains but a trivial pro-
portion of the granules, which are imbedded in a paste of a
grayish-white calcareous clay, identical in aspect and compo-
sition with certain waterworn rocky masses which strew the
beach in front of the boarding-houses. This apparent identity in
all respects except hardness, furnishes a farther proof that the
marl stratum is prolonged to the sea-side, and rests either at the
level of the beach or at so small a depth beneath the surface, as
to be within the action of the surf, which may, I conceive, disturb

249

and bring to shore not only portions of this upper bed, but likewise
of the softer marl below.

Beneath this upper bed in the pit at Elisha West’s, there occurs
a hard, somewhat firmly cemented mass, consisting of light green
grains and a little ordinary sand, the whole being eight feet thick.
In it is a very thin layer of white clay. Lower down we meet a
gray and afterwards a yellowish ferruginous marl, both rather
sandy, and in aggregate thickness about three fect.

Sull lower and throughout the rest of the vertical section we
find a layer of yellowish ferruginous sand, containing a very
moderate proportion of the green grains. Few or no shells are
visible in the perpendicular wall or section disclosed in this pit,
but numerous traces of casts occur, showing that they have once
been there, and intimating the nature of the change which they
have undergone, and the possibility that they may have furnished
to parts of the stratum a small amount of diffused carbonate of
lime and perhaps gypsum.

The marl from the pit of Elisha West displays by analysis the
following

Composition.—In 100 parts:

Greensand, - - - 73:2
Clays candace i oils iGiobes
Quartzose sand, - - 04:0

100:0

The amount of potash, deduced from the above proportion of
greensand is about 8-4 per cent.

This marl is a light yellowish green; adhesive; the admixed
clay giving it a mottled appearance. The washed material is
darker and more distinctly green; the granules are small.

Tinton Falls.—The stratum here is a dark brown and greenish
friable sandstone, which forms a horizontal ledge across the
creek, causing, by its abrupt termination, a sudden fall of about
sixteen feet. It seems to be nothing more than a very sandy and
highly ferruginous marl, consolidated by the cementing action of
the oxide of iron into a moderately compact sandstone. It
abounds in the usual characteristic shells of the marl series, but
these are almost invariably in the state of casts. The amount of
the green grains in the rock is not very considerable, though

250

sufficient, in some of the layers, to impart a decidedly green or
dark olive hue to the otherwise brown mass. Three layers of
nearly similar aspect, all differing somewhat in their hardness
and the proportion of oxide of iron and of the green granules, are
to be observed here.

Whether this rocky stratum at Tinton Falls may not be the
equivalent of the brownish ferruginous sandstone with casts,
which overlies the friable marl in the Nevesinks, near the mouth
of Shrewsbury river, or whether it is the true marl stratum rather
more than usually cemented, and ferruginous, are questions which
it is of some importance to determine, in order to form a just
opinion as to the probability of meeting, at a moderate depth, the
valuable bed of loose greensand itself.

Nearly upon the same horizontal line with the top of this rock,
and at a less distance than a fourth of a mile, a bed of sandy
green marl, not consolidated, shows itself very near the surface of
the fields upon the Monmouth road. The somewhat clayey tex-
ture and greenish hue of the road itself between this point and
Eatontown, is strongly indicative of the proximity of the marl
stratum to the soil.

Poplar Swamp.—At Jacob Woolley’s, Poplar Swamp, the sec-
tion of the marl stratum which is exposed, exhibits three separate
layers. The top bed is about three feet thick; the granules are
of a light green, and mixed with them, is a small quantity of com-
mon siliceous sand. ‘The next, or middle layer, is four feet thick,
of a much darker green; and the bottom bed is of a dull green-
ish ash colour, and contains rather less than fifty per cent. of the
green granules, the rest being clay and ordinary sand. Very few
shells occur at this locality, though bones of the fossil crocodile
and shark’s teeth are occasionally met with.

The middle stratum gives indications, from its darker green
colour and greater freedom from foreign matter of being the most
efficacious of the three as a marl. Astonishing results have been
produced by it when applied in the proportion of from seven to
ten loads to the acre.

This marl lies on Poplar Brook, the source of which is about a
mile west of Mr. Woolley’s, its entrance to the ocean being at
Deal. There is marl in the banks of the meadows and adjacent
ravines throughout nearly the whole length of the stream.

251

Mr. Woolley manured a piece of land in the proportion of two
hundred loads of good stable manure to the acre, applying upon
an adjacent tract of the same soil his marl in the ratio of about
twenty loads per acre. The crops, which were timothy and
clover, were much heavier upon the section which had received
the marl: and there was this additional fact greatly in favour of
the fossil manure over the putrescent one, that the soil was also
entirely free from weeds, while the stable manure had rendered its
own crop very foul.

This greensand stratum at Poplar Swamp seems to be almost
entirely free from any sulphate of iron or other astringent mate-
rial, and, as a consequence, the crops seem not to be scorched by
an extra dose, however lavishly applied.

There can be no doubt that twenty loads of marl per acre
must be regarded as an unnecessarily bountiful dressing, but
computing the relative cost of the two manures, when Suiplayed
in the ratio above stated, we find a considerable disparity in fa-
vour of the greensand. Placing the home value of farm-yard
manure at one hundred cents for each two-horse load, and that of
the marl at twenty-five cents per load, we have the expense of
manuring one acre, two hundred dollars; of marling the same,
five aaaars

This being an experiment, an extravagantly large dressing of
manure was employed, but not Satie the fein average ap-
plication more than the twenty loads of marl surpassed what was
necessary.

Experience has already shown that ]and once amply marled
retains its fertility with little diminution for at least ten or twelve
years, if care be had not to crop it too severely; while with all
practicable precautions, the stable manure must be renewed at
least three times in that interval to maintain in the soil a corre-
sponding degree of vigour.

Marl from Mr. Woolley’s middle bed possesses this

Composition.—In 100 parts :

Greensand, - - - 86 ©

Clay, - - : - 12

Quartzose sand, - - 2
100

252

The amount of potash by experiment in this marl, is 7-5 per
cent.

I present here the analysis of another marl from the same
neighbourhood. It is that of Mr. John Howland, of Poplar
Swamp. Its colour is grayish-green, owing to a coating of car-
bonate of lime on some of the particles. ‘The washed material
is a light and rather rich green.

Composition.—In 100 parts :

Greensand, - - = = 3g Wiehe H2
Clay with a little carbonate of lime, = - 6:5
Quartzose sand, - 4 2 - - 5:0

100°0

The amount of potash deduced from that of the greensand, is
9-7 per cent.

Shark River.—Ely’s mar] pits, on Shark river, present the fol-
lowing layers in the descending series:

Ist. A dark-brown or amber-coloured mixture of sand, aly
and mica; reminding one strongly, both from smell and aspect,
of an ooze of the ocean. It sometimes contains thin seams of
very coarse sand, completely water-worn and rounded. This bed
is between seven and eight feet in thickness, and is seen resting
immediately on an iudurated or cemented marl. It is visible
elsewhere in the neighbourhood, and always has the astringent
character of the corresponding bluish sandy clay already so
often mentioned, with which, in fact, I hold it to be identical as
a stratum.

2d. A hard cemented marl, being a paste of a yellowish white
clay, perhaps containing gypsum, with a moderate sprinkling
of the marl grains. Except in its being a cemented mass it
differs but little from the bed of friable marl which underlies it.
It is two feet thick.

3d. This lower stratum yields the well known marl so much in
request in this part of Monmouth. When moist, the mass pos-
sesses a dark, dull, grayish hue, from the colour of the clay
which coats the granules. When dry the colour is a very dark
plumbago (black-lead) tint, or sometimes a deep olive-green tinge.
It consists of little else than the dark granules, the small quantity

oo

253

of clay present occurring only as a thin coating upon the grains.
The lower part of this layer has a more yellowish hue from a
greater excess of the clay, which is here rather ferruginous.
The thickness of the bed is not known, though it has been pene-
trated sixteen or seventeen feet.

I have witnessed its action on some very poor light soils, which
were rendered highly fertile from the use of this marl in a first
dressing of five loads to the acre, and an equal quantity at the
next rotation of the crops.

The best marl of Ely’s bed exhibits the following

Composition.—In 100 parts:

Greensand, - : - 80
Clays Sub Io. shy VOM SoH
(Quartzose sand, - = - none.

100

The amount of potash in this marl, by calculation, is 9:2 per
cent.

The following analysis shows the composition of another marl
of this neighbourhood, that from the pit of Mr. John Shaft, of
Shark river.

The specimen was taken from near the mill, and is the best of
the several samples procured.

Composition.—In 100 parts :

Greensand, - - - 87
Clay, - - - - = 11
Quartzose sand, - - - 2

100

The amount of potash ascertained by analysis, is 9.5 per cent.

Squankum.—Thorp’s marl, near Squankum, presents the fol-
lowing varieties :

Ist: On the top, a bed of diluvial sand and gravel, and in
certain places a coarse, ferruginous sandstone, sometimes two
feet thick.

2d. A light greenish-blue clay, the upper part of which some-
times shades into a brown sandy clay, like the corresponding bed
at Shark river. One portion of this contains a small mixture of
the green granules. This portion appears, in fact, to graduate

22.

254

into the upper part of the marl bed, in which there is not un-
frequently as much as fifty per cent. of the clay itself.

3d. The inferior layer is the true marl stratum, consisting of
little else than the green granules. When dry, the colour of the
mass is a tolerably light grayish green, but not uniform, light
specks occurring throughout the marl.

When the heaps have dried, the external grains are coated, in
some degree, with a white efflorescence. The upper portion of
the bed, in consequence of containing much of the astringent
clay, presents a good deal of the yellowish efflorescence ascribed
to copperas. The depth which has been reached in the pits is
about twenty feet, and hitherto the bottom of the marl has not
been struck. The lower part of the stratum is conceived to
contain the best marl. It is not free from decomposing sulphuret
of iron, judging from the strong odour of sulphur which every
pile of it exhales, and which it does not lose even after being
conveyed to a distance, and long exposed to the weather. It
probably, therefore, contains a slight impregnation of sulphate of
iron or copperas, but not enough to injure it, if we are to infer
from the reputation which this marl possesses.

At the pits, which are very extensive, the marl is sold at the
rate of 372 cents the load, the purchasers having to dig it. It is
transported by wagons to a distance, in some directions, of twenty
miles, and retailed, when hauled that far, at the rate of 10 or
even 122 cents per bushel, being very profitably spread upon the
soil in the small proportion of twenty-five or even twenty bushels
to the acre.

In its external aspect this marl does not differ from many
others in the State, nor am I convinced that it surpasses a nume-
rous list in point of efficacy as a fertilizing agent. The amount
of potash which it contains is materially less than belongs to a
large proportion of the better marls of the region.

Marl from the upper part of the bed at Squankum.
Composition.—In 100 parts:

Greensand, - - - 58°36
Clay, - . - . 27-64
Quartzose sand, - - 14:00

100-00

255

The amount of potash in this marl, deduced from an analysis of
the greensand of this locality, is 6-1 per cent.

Marl from the middle part of the bed at Squankum.

Composition.—In 100 parts:

Greensand, - - - 35°72
Clay, - - - - 54:28
Quartzose sand, - - 10-00

100-00

The amount of potash in this marl, deduced from that of the
greensand, is 3°7 per cent.

Marl from the lower part of the bed at Squankum.

Composition.—In 100 parts:

Greensand, - : - 68-29
Clay, - - - - 27°71
Quartzose sand, 3 2 4:00

100-00

The amount of potash which this marl contains, derived from
an analysis of the selected grains, is 7:1 per cent.

In the neighbourhood of Mount’s Mills or Berkelue’s, at Mr.
Rue’s, half a mile south of Spotswood, there is a black clay
like that of Middletown Point, containing a considerable quantity
of the marl. It has been thought to be somewhat beneficial to
the land. It is near Mr. Berkelue’s mill-pond, and not in the
lowest ground. There is a considerable undulation of the surface
in this quarter, though the denudation would seem not to have
reached a low level. The superficial. stratum is sandy, contain-
ing also some of the loose materials characteristic of the marl
region.

At the pits of William Johnson, one mile east of the former,
the supposed marl stratum exhibits a small proportion of the
greensand with much siliceous sand, some clay and mica, and
has a decidedly sulphurous odour; it also tastes of copperas,

256

and has a yellow crust. These pits lie in the side of a hill, on
the road from the mills to Johnson’s house. Around this neigh-
bourhood the land is rather high, and hence perhaps the true
mar] has not yet been reached. The proximity of this impure
mar] to the railroad, makes it desirable, if possible, to learn
whether the true greensand bed does not lie below it at an ac-
cessible depth.

Three miles from Englishtown, on the Matchaponix creek, at
John Perrine’s saw-mill, the same stratum is seen as at Rue’s.
It is not so destitute of the grains of marl as to be entirely unfit
for use. It occupies the bed of the creek for some distance
below the saw-mill. It is sandy and micaceous, with small
irregular concretions of clay cemented by oxide of iron, and a
few grains of marl.

In many parts of this section there is a stratum of a mottled
bluish clay with blotches of yellow ferruginous clay. This lies
over the spurious marl stratum, and looks not unlike the upper
marl bed at Middletown and its vicinity.

Around the parsonage, two and a half miles from Englishtown,
on the road to Freehold, the marl is pretty good, though a little
impure from containing some sand and clay. At no great depth
it contains shells and other fossils. The soil is sandy, but grows
better to the northwest. All the indications. of the marl region
are present here.

In and around the farm of Mr. Hunt, one mile from Blooms-
burg tavern, the marl lies extensively denuded in the meadows.
It is pretty good, consisting mainly of greenish grains, with a
good deal of clay. These meadows are very ferruginous, and
contain bog iron ore.

Marl from the farm of Mr. Hunt.

Composition.—In 100 parts:

Greensand, - - - 75:0
Clay, i - - - 19°5
Quartzose sand, = - 55

100°0

The proportion of potash which this marl contains, deduced
from that in the greensand, is 8-6 per cent.

257

The marl seems not to be known much farther to the north-
west, in which direction there is a low range of hills of denu-
dation.

Below the dam at Bargain’s mill, on the Millstone creek, the
spurious marl stratum is visible again. At Lewis Perrine’s, half
way between this and the Presbyterian church, the marl is found,
but not very good; it lies rather high in the fields. The true
marl is known here as far west as Mr. Van’s, two miles farther
towards the railroad on Rocky brook, one mile below Imlay’s
mills. The quality is not known, but it is supposed to be the
inferior sort.

At Willow Tavern or Clarksburg, a thin layer occurs in the
roadside, being a light-green marl with yellow specks. Beneath
this there is a whitish bed of siliceous sand with white clay and
a very few yellow and green specks.

The ochrey olive hue, so common in the clay of the marl
region further to the southwest, is seen here upon the road, and
though no marl has been dug, I do not doubt its existing in this
quarter. Marl, declared to be good, has been found two miles
to the northwest of Willow Tavern.

The country between this and Allentown is, for a certain dis-
tance, somewhat hilly, then flat and very sandy. Hills occur of
some magnitude near the head waters of Rocky brook, and
range from east to west. The highest is called Pine Hill, and is
the same which is seen so conspicuously from Hendrick Cono-
ver’s insulated hill, as before noticed. We pass through a gap
in this range, in coming from the northeast to the Willow
Tavern.

Two ranges of high grounds seem to extend in parallel direc-
tions to the southwest, one on each side of the road going to
Wrightsville, before reaching which place, however, the western
one is crossed. To the east is Cream Ridge.

At the head of Montgomery’s mill-pond, near Allentown,
Mr. Burden has dug in search of marl. It is very poor (of the
spurious kind), no green grains being visible, and it tastes strongly
of copperas. At the rate of twenty loads to the acre it destroys
the crop. A very slight dressing, however, was thought to be
beneficial to potatoes. The stratum is the blue sandy clay
usually so astringent.

22*

258

At Crosswick’s, Gideon Middleton has a mar] pit near the mill,
in which the layers are as follows:

1. A micaceous tough clay on the top.

2. A rather greenish gray marl, somewhat micaceous, but
pretty rich. Beneath this, one foot of ferruginous marly concre-
tions, each about the size of a man’s head.

3. A dark blue marl.

4. A black sand and marl.

In sinking a well at his house, many years ago, the beds
traversed were ten feet of yellow sand, then twenty-seven feet of
marl, and below all a white sand. Low down in the pit just
spoken of, shells, belemnites, &c. occur. Fossil wood, with
much pyrites attached, is sometimes seen in the marl pit near the
bottom.

This marl is highly fertilizing, as Mr. Middleton’s fields show.
Mr. M. has mixed it with lime with very beneficial results. In the
upper stratum, yellow incrustations of efflorescent sulphate of
iron abound.

Marl from the farm of Gideon Middleton.
Composition.—In 100 parts:

Greensand, - - - 68:00
Clay, io 2totnu, -besd. ect: 1eeao ie
Quartzose sand, - : 3:00

100:00

The proportion of potash which this marl contains, deduced
from that in the greensand, is 7:8 per cent.

The marl is very good one mile lower down upon Cross-
wick’s creek, at David Killey’s. It lies in a bank on the side of
the meadows along the creek, and has a top layer of the black
astringent clayey or spurious marl. (There is a good marl on
Crosswick’s creek, half a mile above Hogsback landing, and J
am told it extends still lower down. ‘This proximity to the rail-
road is a matter of much importance to the adjacent region. |

Near the Sand Hills, and in places between these and Borden-
town, the lower or spurious marl stratum is visible in the sections
of the railroad, and I am now firmly of the opinion, that the clay

2909

with lignite at Bordentown landing and below, is the lower bed .
of the marl formation, and identical with the astringent blue clay
bed beneath the true marl or greensand at the base of Nevesink
Hills and elsewhere in Monmouth county, and throughout a great
portion of the whole marl region.

Shelltown.—Howard’s mar] is near this place on the south side
of Crosswick’s creek, and presents both the true marl stratum and
the astringent clay. The marl! is dark, friable, smells of sulphur,
and is found to be very efficacious. The overlying lead-coloured
clay is somewhat micaceous, and contains a trivial quantity of
the greensand, being in all respects like the underlying bed which
shows itself at Wall’s mill near Burlington. It resembles very
much the character of the bed where it caps the marl at Cross-
wick’s and in the neighbourhood.

On the road from Shelltown to James S. Lawrence’s, which is
one mile southwest from Varmington; the same overlying bed is
exposed in numerous places in the banks of the meadows.

All these cases are adduced to show that the true marl over-
lies and alternates with the dark astringent clay along nearly the
whole northwestern edge of the marl tract, as, for example, near
Burlington and Camden.

Fine exposures of the marl offer themselves to view in the
vicinity of the residence of Mr. Lawrence. ‘The soil itself is a
brown ferruginous loam, being a portion of a narrow tract of
red clayey soil, which extends. a considerable distance northeast
and southwest, passing by Arneystown, and exibiting wherever
it is seen, every evidence, from its texture and the minute water-
worn grains of quartz, of its having resulted from the breaking
up of an overlying stratum of brown sandstone. In some of
Mr. Lawrence’s fields, it contains a very sensible quantity of the
green granules. The upper part of the marl stratum here differs
materially in aspect from the lower. For a thickness of several
feet, it is little else than a mass of decomposed shells almost inva-
riably in the state of casts, the shells replaced by oxide of iron.
An inconsiderable proportion of the green grains is mingled with
a yellowish white pasty matter, which is a mixture principally of
sulphate and carbonate of lime, derived no doubt from the shells, .
and which imparts many valuable qualities to the marl.

The lower stratum is a mass of dark greensand, in which we

260

. witness few traces of the changes noticed in the materials of the
mass above. The quantity of oxide of iron in the free state
mixed with the mar] causes it to be rather hard to dig; this is
the case with nearly all the more ferruginous kinds, but a brief
exposure to the air renders it friable, when it is found to be a
very powerfully fertilizing marl. Striking benefits result from
the use of this marl when it is applied in the ratio of about ten
loads to the acre. In this bed have been found teeth of the
mosasaurus and several bones apparently of the fossil crocodile.
Mr. Lawrence states that his lower or dark green mar], which is
very full of the astringent matter or sulphate of iron, will not
admit of being lavishly employed, for it then invariably poisons
the crop. If as much as twenty-five loads be used, the growth of
the corn is seriously checked; nor does it recruit until late in the
season, after which the vegetation is wonderfully quickened. The
upper stratum, on the other hand, will admit of being applied in
any excess, one hundred loads or even more, producing no dele-
terious effects upon the crop. Where the banks of the meadows
are high, a different stratum from either of the previous two is
seen, and to all appearance occupying a higher place in the
series. This is the calcareous sandy stratum which in another
part of this Report I alluded to as being in all. probability a
deposit of the same date with the limestone of Vincentown and
Mannington. It is here a yellow calcareous sand with scattered
grains of marl, and with a multitude of solid casts of various
fossils, some of which do not show themselves in the green marl
beneath. In this bed I have procured coprolites.* All the casts
m question consist chiefly of carbonate of lime in an earthy state
mixed with a little clay and sand.

The stratum in some places is more than twenty feet in thick-
ness. Being the upper bed, it is in many instances the only
accessible one, in which case I think it deserves to be employed
as a substitute for marl, not merely for the amount of calca-
reous matter in it, but for the quantity of the greensand. Bones
of some reptile, the crocodile apparently, are found in this stratum,
and we may hence form a conjecture of the source of the copro-
lites. From the same bed we may procure solid internal casts

* Coprolites, are the fossilized dung of extinct animals.

261

of claws of a fossil crab, two species of baculites, teeth of the cro-
codile, and many interesting species of bivalve and univalve shells.

In a deep ravine on the opposite or west side of Crosswick’s
creek, and a little lower down than where the previous beds are
seen, and very near the line of an ancient Indian path, we have
an exhibition of a very different group of beds.

The upper layer is a yellow sand. A little beneath this, there
occurs a brownish, ferruginous, sandy rock, characterized by
casts of the ostrea falcata, identical in all its features with the
stratum containing ostrea falcata, and resting high up in the cliffs
of the Nevesinks. Next beneath is a dark siliceous sand, with
casts of shells, and masses which appear to have been lignite or
fossil-wood, replaced by a sandy clay. This bed is very astrin-
gent, the surface in many places being coated with the yellow
efflorescence. Lower still there exists a mottled gray and yellow
sand, and beneath all a gray sand with lumps of what was once
lignite but is now clay, having all the markings and occupying
the place of the woody matter now removed.

At John Miers, two miles south of the localities above de-
scribed, excellent marl is seen in two layers, the top one being a
light green, with little or no white incrustation upon the grains,
and this graduating into the inferior, or dark green marl, which
seems to be rather less friable and considerably more ferruginous.
The grains in the lower part of the stratum acquire, when drying
in the heap, the white tasteless incrustation or efflorescence so
common to the marls of the region, and which chemical experi-
ment establishes to be the sulphate of lime or gypsum.

Marl from the farm of John Miers, on Lahaway creek, near
Hornerstown, Upper Freehold township, Monmouth county.
Upper part of the bed.

Description.—Colour, light green, clayey and adhesive. The
washed granules, which are small, are of the same bright green
colour.

Composition.—In 100 parts:

Greensand, 2 - 2 84:5
Clay, - - - - 14°5
Quartzose sand, : - El

262

The proportion of potash which this marl contains, deduced
from that of the green grains, is 9°7.

Lower portion of the stratum.

Description.—Colour, bluish-gray, texture clayey and tena-
cious. The washed granules dark, almost black, and very large.

Composition.—In 100 parts:

Greensand, - - - 77°45
ape ios ieee ia) aie os era ass
Quartzose sand, - - none.

100-00

The proportion of potash, by analysis, is 9 per cent.

It is an observation made in this neighbourhood, and one in
complete accordance with my observations throughout the marl
tract, in its range from hence through Burlington and Gloucester
counties, and even Salem, that when the light green shows itself
it is usually along the eastern side of the marl belt, and invariably
occupying a position on the top of the dark greensand. The
latter, I find in many districts to be esteemed the most efficient of
the two varieties. '

At Snuff Mil, on a small tributary of Crosswick’s creek, about
one mile north of New Egypt, we witness the same limestone
bed which appears lower down the State, at Vincentown, and in
Salem county. It holds the same position on the top of the green
marl, is a stratum of about a foot in thickness, and contains the
same corals or zoophytes—for example, the same alcyonia, and
the same shells seen in the districts where this stratum of rock is
of more important thickness.

At Fuller Horner’s, on Crosswick’s creek, about a third of a
mile below New Egypt, there is a bank exposing the strata, where,
during the last twenty years, enormous quantities of marl have
been procured for the use of the neighbourhood. The section is
between twenty and twenty-five feet high. Near the top of the
bank, the upper layer is a greenish siliceous and slightly calca-.
reous sand, and beneath this occurs the rubbly, straw-coloured,
and somewhat sandy limestone, the frequent capping to the marl.
Both these layers are represented in precisely the same order

263

near Vincentown. In the bank before us the limestone is rarely
more than one foot thick, and reposes upon the greensand, or
marl bed, which consists of a series of thin layers of different
tints, and various degrees of purity, occupying a depth of at least
twenty feet.

This is a locality containing some very interesting fossils, but
the present is not the place to treat of them. The marl has the
very usual odour of sulphur, and exhibits, when dry, the gray or
white efflorescence. It enjoys a high reputation as a manure.
Most of the shells in it show that the carbonate of lime has been
nearly all supplanted by oxide of iron, and here, as in the instance
of many other greensand marls, the virtues of the mass are not to
be attributed to the lime, but to the specific power of the consti-
tuents of the dark granules, chiefly the potash.

Marl from the farm of Fuller Horner, New Egypt.
Upper part of the bed.

Description.—Colour dark olive-green; washed granules very
dark green, size large.

Composition.—In 100 parts:

Greensand, - - - 100
Clay, - : - - none.
Quartzose sand, - - none.

100

The proportion of potash which this marl contains by analysis,
is 11 per cent.

Marl from the bridge at Hornerstown, Monmouth county.

Description.—Colour, a rather light green. The washed
grains quite small, and of a richer green.

Composition.—In 100 parts:

Greensand, - - - 75°90
Clay, - - 2 bite 20-10
Quartzose, - - - 4:00

100-00

264

The proportion of potash in this marl by direct amalgaiets is 9.1
per cent.

Near Arneystown, the marl is to be met with in nearly all the
meadows and low grounds. The soil is the red or brown loam,
derived from the destruction of the brown ferruginous. sandstone,
one of the principal upper beds of the secondary strata of the _
region.

The underlying marl does not, to my knowledge, offer either
the overlying light-green layer, or the still superior seam of lime-
stone, a fact Bee ine what has been said, that these lie
chiefly upon the eastern or ocean side of the marl tract. The
dark mar] here is highly effective upon the crops.

Between Arneystown and Hornerstown, we meet the same
superior thick mass of calcareous sand full of organic remains ;
these are usually in the state of solid casts of the interior of the
shells. ‘The whole corresponds to what we see nearer to Var-
mintown, at Mr. Lawrence’s. The spot where this bed best
shows itself is on the hill side overlooking the meadows at Cross-
wick’s creek, and it is thought that we may behold here, as. at
Lawrence’s a slight dip of the strata to the southeast. Upon the
other side of the valley, on a level with the meadows, we meet
with a gray loose sandstone full of ostrea falcata, in an undis-
solved and beautifully pearly condition.

At Cookestown, a rock, equivalent to the Vincentown seam of
limestone, is seen lying near the level of the stream.

At Imlay’s, where the Monmouth road crosses Crosswick’s
creek, and about half a mile below Fuller Horner’s beds, the
marl series is exposed at a considerable elevation above the
creek. Gray sand shows itself on the top, then follows a yellow
sand, with ferruginous bands of cemented shells, and then sand
with green grains, through a thickness of several feet, down to
the top of the pure greensand stratum.

A light-green marl, four feet thick, full of casts of shells suc-
ceeds; below which lies the dark-green marl, rather coherent
or slightly cemented by oxide of iron, and a few shells.

The top of this is many feet above the meadows, and I can
well comprehend how, by the descent of the meadows to Law-
rence’s, space enough may exist sor the siliceous beds, cha-

265

racterized by ostrea falcata, to occupy a yet lower place in the
series.

Marl from the farm of William Imlay, between Plattsburg
and Arneytown, Burlington county.
Description.—Colour, dark olive-green ; washed granules, dark
clear green, and of large size.
Composition.—In 100 parts:

Greensand, - = - 91-85
Se ea 6°65
Quartzose sand, - - 1:50

100-00

The proportion of potash in this marl, deduced from that of the
greensand, is 10°5 per cent.

Mari from Crosswicks creek, at its intersection with the Mount
Folly and Monmouth road.

Description—Colour, dark earthy green.
Composition.—In 100 parts:

Greensand, - - - 82:22
Clay, - - - - 13°58
Quartzose sand, - - 4:20

100-00

The proportion of potash in this marl, as deduced from the
greensand, is 9°6 per cent.

Plattsburg, or Sykesville——Mar] of excellent quality is procured
at several places in this neighbourhood, as the following analyses

will show.

Marl from Poke Hill, near Plattsburg, Burlington county.
Description.—Colour, a greenish olive-gray ; washed granules,
a rich dark olive-green, rather above the medium size.
Composition.—In 100 parts:

Greensand, - - - 98.0
Ch, gee ane he 2:0
Quartzose sand, - - none.

100-0

23

266

The proportion of potash in this marl, by analysis, is 10-7 per
cent.

Marl from the farm of Sarah Willis, half a mile northwest
of Platisburg.

Description.—Colour, a rich green; the washed granules have
a still richer tint; they are of medium size.

Composition.—In 100 parts:

Greensand, - . en 2 |
Clay, Bi thei betas
Quartzose sand, - ~ 2-0

100-00

The proportion of potash in this marl, deduced from that in the
greensand, is 7-9 per cent.

Marl from the farm of John Pancoast, half a mile northwest
of Plattsburg, Burlington county.

Description.—Colour, light verdigris-green; the washed granules
even lighter in colour; size, small.
Composition.—In 100 parts :

Greensand, - - - 76:50
Clay, - - ~ - 22-00
Quartzose sand, . - 1°50

100-00

The proportion of potash in this marl, deduced from that in
greensand, is 8°7 per cent.

Marl from the farm of Thomas Earl, three quarters of a mile
northwest of Platisburg.

Description.—Colour, earthy pea-green; the washed grains,
small in size and of a dark sea-green colour.
Composition.—In 100 parts:

Greensand, - e 56
Clay, 2 - : - 36
Quartzose sand, - - 8

267

The proportion of potash in this marl, deduced from that in the
greensand, is 6°4 per cent.

Marl from the farm of Caleb Newbold, two miles southwest
of Platisburg, west side of Lowland road.

Description.—Colour, pea-green; the washed grains small in
size, and of a sea-green colour.

Composition.—In 100 parts:

Greensand, - = : 84:10

: Clay, - - - - 15:90
(Quartzose sand, - - none.

100-00

The proportion of potash in this marl, by direct analysis, is
9-2 per cent.

Marl from the farm of Thomas Black, two miles west of
Platisburg.

Description.—Colour, dark dull green, but little changed by
washing; granules large.

Composition.—In 100 parts:

Greensand, - = Z 90-50
Clay, - - - - 9.50
Quartzose sand, - none.

: 100:00

The proportion of potash which this marl contains, ascertained
by direct analysis, is 10°8.

Arney’s Mount is a considerable hill at the Friends’ meeting-
house, one and a half miles southwest from Juliustown. The
sandy soil of the neighbourhood, even that of the road, is mixed
with the greensand, so that its colour is sensibly influenced by it.
Eastward from the meeting-house, a few hundred yards, there
is a small opening on the road, where the ferruginous conglome-
rate has been quarried. Most of the cemented particles in this
rock are grains of coarse siliceous sand, but some of them are

268

felspar. It is very hard and durable, and shows no departure
from the horizontal position.

On the top of Arney’s Mount, there lies a pretty thick bed of
this sandstone; it is largely quarried, dipping very gently to the
east. This mount is distinctly visible from Mount Holly, from
which there is a rather extensive view. The whole surrounding
landscape is extremely flat, the eastern horizon, more especially,
being perfectly uniform. Marl occurs, near the surface of the
fields, to the southeast; its existence being shown by the water
oozing forth along the base of the hill or mount.

Marl from the farm of Thomas Coats, half a mile southwest
of Juliustown, Burlington county.

Description.—Colour, a very rich verdigris-green; the washed
grains of a darker colour and very small.
Composition.—In 100 parts:

Greensand, - - - 77°25
Clay, - - - - 12-75
Quartzose sand, - - 10:00

100:00

The proportion of potash in this mar], deduced from that in the
greensand, is 8:8 per cent.

On the Assiscunk (Barker’s branch) a little above Slabtown,
marl has recently been opened. It is not good, owing to its con-
taining too much of the ordinary impurities. ‘The opening is on
the side of the road. It is said to contain fossils.

Higher up, on the same branch, the marl seems to be consi-
derably better, yet it is too siliceous to be ranked as the best
kind.

Burlington.—The nearest place to the river where marl occurs
in this vicinity, appears to be at the mill-pond near Wall’s mill,
one mile south of the town. The pit is not deep, owing to the
stratum being wet. It is exposed in a spot where the dam some
time since gave way, and its top is very little below the level of
the original water course. The top of the stratum is covered by
a thin, hard, ferruginous crust. The mar! is highly siliceous *and

269
micaceous, yet contains a very sensible proportion of the green
particles. No fossils appear in it. It has a strong sulphurous
odour, and presents the yellow efflorescence and astringent taste
of copperas, and resembles pretty closely that at Johnson’s, near
Mount’s mills.

This material manifestly underlies the true greensand, which
here and at Bordentown, and indeed generally throughout the
belt of country bordering the Delaware, has been extensively
swept away along the northwestern margin of the formation by
denuding currents.

At Costiil’s mill the marl is pretty much of the same character,
containing perhaps rather more of the black clay and siliceous
sand. Sulphuret of tron also occurs in it, in little nodular lumps.
It smells strongly of sulphur. When applied in hight dressings to
the land, it has been found useful. It is said to contain shells and
shark’s teeth.

On the Rancocus, near Franklin Park, the good marl lies at
the level of the tide, being covered by the yellow ferruginous
sand, and has much clay mixed with it. It has been found very
beneficial, but is regarded as inferior to that which lies higher up
the Rancocus. It contains fossils.

Higher up the Rancocus, the marl extends to Pemberton and
Vincentown, and, it would appear, almost to the vicinity of the
Pine Cottage.

Marl from Pemberton Mills.— Upper part of the Stratum.

Description.—Colour, yellowish pea-green; the washed grains
of a darker green and of small size.
Composition.—In 100 parts:

- Greensand, - - - 54:13
Clay, es ee ete) eee
Quartzose sand, - - 25.40

100-00

The proportion of potash in this marl, by direct analysis, is

6°5 per cent.
23*

270

Lower part of the Stratum.

Description.—Colour, very light greenish-gray ; highly clayey
and adhesive.
Composition.—In 100 parts:

Greensand, - - - 38°05
Chy, <a. - ea
Quartzose sand, - - 35:00

100-00

The proportion of potash which this marl contains, deduced —

from that in the greensand, is 4°3 per cent.

On the Haybridge run, a mile and a half north of Pemberton,
there is very good green marl which is dug near the road. Over
this is a thin layer, containing much of the copperas earth in a
state of efflorescence.

At Forsyth’s, north of the road between Pemberton and Lis-

bon, and one and a half miles from the former place, there is
very good dark-green marl, lying on the surface of the meadow.
It contains numerous fossils. On the edge of the meadow, and

near the top of the marl, there were found, some years ago, the

principal portions of the head of a mastodon, and also a tusk,
pieces of the tibia, ribs, &c. It would seem, from the state of
the bones, and the unworn condition of the teeth, to have been
a young one. The head was exposed to the air, lying only
eighteen inches below the surface of the meadow, and was much
decayed.

In a ravine, on the edge of the meadow, and lying in the yel-
low sand which covers the marl, there was found a mass having
all the external characteristics of retanasphaltum.

Shark’s teeth, phosphate of iron, &c. occur in the marl of this
vicinity.

Birmingham.—The marl is generally of a superior quality
along the north branch of the Rancocus, both above and below
Birmingham. On the north side of the stream, it is extensively
opened on the farm of Jacob Gaskill, where the greensand may
be penetrated to a depth of twenty-five feet without serious
inconvenience from the infiltration of water into the pits.

:
+04
’ ne

271
Marl from the farm of Jacob Gaskill, near Birmingham, Burlington
county.— Lower part of the bed..

Description.—Colour, dark greenish-gray ; washed granules,
dark olive-green; rather large.

Composition.—In 100 parts:

Greensand, - . - 92°9
Clay, - - . - 6°1
Quartzose sand, = - 1-0

100:0

The proportion of potash which this marl contains, by analysis,
is 10-8 per cent.

Marl from the farm of John Woolston, a fourth of a mile south of
Birmingham, Rancocus creek.

Description.—Colour, dull grayish-green; the washed grains
of a light green colour, and rather small size.

Composition.—In 100 parts:

Greensand, - - - 82:60

Clay, . - = : - 10:40

> Quartzose sand, - . 7-00
100-00

The proportion of potash, deduced from that of the greensand,
is 9°5 per cent.

Marl from the farm of John Dobbins, a fourth of a mile south of
Birmingham, Rancocus creek.

Description.—Colour, dark olive-green; texture, granular, gra-
nules of a medium size; when washed of a deep full green.
Composition.—In 100 parts:

Greensand, - - a 92°75
Clay, - - - - 6:25
Quartzose sand - . 1:00

100-00

The potash, by direct analysis, in this marl is 10-02 per cent.

272

Marl from the farm of Mr. Charles Euen, one-fourth of a mile south
of Birmingham, on Rancocus creek.
Description.—Colour, sea-green; the washed grains of rather
large size, and of a very rich green colour.
Composition.—In 100 parts:

Greensand, - - 3 91:35

Olay, - - - 8°65

(Quartzose sand, < = none. .
100-00

The proportion of potash in this marl, by analysis, is 10 per cent.

Vincentown.—The proportion of greensand in the marls of the
vicinity of Vincentown, though such as to confer decidedly active
properties, is yet somewhat inferior to that of some preceding
localities. In other respects these marls are of ordinary purity.

Marl from the farm of Mr. Job Frick, near Vincentown.

Description.—Colour, dull greenish-gray ; washed granules of a
dark rich green, and of medium size. 7
Composition.—In 100 parts:

Greensand, - - 1755
Clay,. - : - - 20°45
Quartzose sand, : Z 2:00

100-00

The proportion of potash in this marl, by analysis, is 8°3 per cent.

Marl from the farm of Mr. Benjamin Peacock, near Vincentown.
Description.—Colour, dark grayish-green; the washed grains —
of a deeper green and small size.
Composition.—In 100 parts:

Greensand, - - - 76:13
@lay, | --. .-. .. -hitee-deuuliigts
Quartzose sand, - - 8°42

100-00

273

The proportion of potash, as deduced from that of the green-
sand, is 8°7 per cent.

Marl from the farm of Edward Hilliard, half a mile south of

Vincentown.— Lower portion of the stratum.

Description.—Cclour, verdigris-green; the washed grains of a
darker colour, and very small.

Composition.—In 100 parts:

Greensand, - = - 72°58
Clay, - - - - 19-92
Quartzose sand, - - 7:50

100-00

The proportion of potash in this marl, by analysis, is 7-9 per cent.

Eayrstown.—The marl in the meadow midway between Eayrs-
town and Newbold’s Corner, presents something unusual. The
grains are generally coarse and dark green, while some are very
light, almost white, and seem to be decomposing. These owe
their whiteness to an incrustation of carbonate of lime, their in-
terior being of a very light green.

I here submit the analyses of two marls from the vicinity of
Eayrstown, by which it will appear that the greensand formation
exists here in considerable purity.

Marl from the farm of Thomas Edwards, half a mile southwest of
Eayrstown.

Description.—Colour, lead-gray; contains a few particles of
carbonate of lime, adhesive; the washed granules are light grayish-
green, and of medium size.

Composition.—In 100 parts:

Greensand, - - - 93.5
Clay, . - - a 6°5
Quartzose sand, - - - none.

100-0

The proportion of potash which this marl contains, is 10-1 per
cent.

274

Marl from the farm of Messrs. Thomas and Wiliam Edwards, near |
Eayrstown.

Description.—Colour, dark verdigris green; the washed grains,
quite small and of a very rich green.

Composition.—In 100 parts :

Greensand, - - - 81:59
Clay, - - Bs - 18°41
Quartzose sand, - none.

100-00

The proportion of potash in this marl, deduced’ from that of the
greensand, is 9-30 per cent.

Points south of the Rancocus.—On Haines’s creek, or the main
south branch of the Rancocus, one mile and a half below Haines’s
place, the banks exhibit the black micaceous and astringent clay,
ascertained to rest throughout a considerable area beneath the true
green marl. In a meadow half a mile to the north of Joseph
Haines’s the two beds are seen in contact.

At Charles Haines’s mill, two miles below Medford, on the
creek, a section is seen, exhibiting on the top a greenish siliceous
sand; beneath this, a gray sand some feet thick, containing a
small proportion of the green granules; and under this, the straw-
coloured limestone two feet thick.

These beds hold the same order, and are identical in com-
position with those above the green marl at New Egypt and
elsewhere, towards the eastern side of the “ marl tract.” One-
fourth of a mile from the mill, the beds have been cut through, in
digging a well, into the greensand underneath. The limestone
was reached between seven and eight feet below the surface. It
was in thin irregular beds, separated by incohering sand and
calcareous grains, similar to the mixture which composes the
rock ; its total thickness is about six feet; the organic remains are
the same which characterize the limestone at Vincentown. The
marl stratum here possesses when dry, a dark, slightly greenish-
gray hue, the granules being coated with a very copious efflo-
rescence ; it resembles the marl at Inskeep’s. In the upper part of
the bed there is a layer four feet thick, of decomposed shells,
(Gryphea, &c.) mingled with the green grains, in a dark friable

275

brownish mass; the efficacy of this upon the soil is found to be
very great. Capping this upper layer, the diluvium contains a
bottom band of very ferruginous cemented sand and gravel, a
foot and more in thickness.

The extensive range of meadows in which these exposures of
the strata occur, meets the meadows of the Rancocus about two
miles above the limit of the tide, at Joseph Haines’s. They con-
tain marl along their banks almost to the source of the stream.
None of the overlying limestone seems to occur nearer the
Delaware than this point, for the marl here is the uppermost
stratum.

The limestone belt measured from northwest to southeast,
appears, as far as exposed, to be about one mile wide, and there
are pretty good reasons for concluding that it expands still more
to the southeast. In the marl at J. Haines’s, shells, shark’s teeth
and bones are occasionally found.

The marl is traceable as far to the southeast as Pricket’s, upon
the edge of the sandy tract, denominated from the prevailing
timber, the Pines. It is here very similar to the upper and mo-
derately pure variety seen in the stratum at Medford.

Near Medford, which is about two miles from the edge of the
pines, pretty good marl abounds in all the ravines or meadows
adjacent to the town.

Evesham.—Some of the marl in this vicinity is remarkably
pure, as the following analysis will show:

Marl from Evesham, Burlington county.

Description.—Colour, a medium tint of green; granules of
rather large size.

Composition.—In 100 parts :

Greensand, - - - 100
Clay, - - - - none.
Quartzose sand, - - none.

The proportion of potash, by direct analysis, is 11 per cent.

On the north branch of Cooper’s creek, and about one and a
half miles south by west from Swain’s, the marl is very exten-
sively laid bare in the banks bordering the meadows. The marl

276

pits of Mr. Buck, J. P. Rogers and others, are very extensive.
At the former, which are low, the marl is of a pretty light bright
green; upon drying, it does not become covered with much
efflorescence. The excavations enter the stratum about ten feet;
no shells or other fossils are seen. The sand of the overlying
diluvium contains some of the green granules, and a layer which
has somewhat the aspect of a green clay, derived perhaps from
the granular marl below. That this overlying bed is certainly
diluvium, is proved by the fact of its occasionally filling troughs
or undulations in the top of the marl, which seems to have been
furrowed at some time by rapid currents sweeping over its surface.

At J. P. Rogers’, the colour of the marl is darker, being a deep
dull bluish green. These varieties in colour are due more often
to small admixtures of differently coloured clays than to an in-
trinsic difference in the tints of the granules themselves. The
marl now before us exhibits a copious white efflorescence on
drying. It is certainly a curious fact, but is true, as far as I have
yet observed, that the darker marls have more of this than the
light ones. The dark and light green varieties in this quarter,
seem not to be, as in many places elsewhere, distinct beds. At
the depth of about ten feet numerous fossils occur. Besides the
ordinary shells, there have been found sharks’ teeth, and a por-
tion of the jaw of a crocodile, containing three of the teeth in
their sockets. A small mass of a black bituminous substance
possessing all the characters which belong to retinasphaltum,
was procured two feet beneath the top of the marl. It is iden-
tical in all respects with the mass found near the top of the marl
at Forsyth’s.

At Cooperstown, upon Cooper’s creek, five miles from Camden,
there is a marl much in use throughout the neighbourhood; it
lies near the surface, being covered by a yellowish mottled bluish
clay, apparently the same with the brick earth upon which Phila-
delphia stands.

It has been penetrated in pits which dre dry, to the depth of
twenty-four feet. It is a tough unctuous bluish clayey stratum,
with only a moderate per-centage of the green granules, and a
considerable amount of ,the astringent matters, (copperas, &c.)
It contains numerous shells, some of them of great size, an ozygra
costata found in it weighing upwards of nine pounds.

277

Marl from the farm of William Skinner, near Cooperstown,
Gloucester county.

Description.—Colour, dark dull green; the washed granules
more distinctly green; these are of large size.

Composition.—In 100 parts:

Greensand, - = = 85°63
Cee ee ee ome OO ay
(Quartzose sand, - - none.

100-00

The proportion of potash in this marl, deduced from that in the
greensand, is 9°8 per cent.

Within one mile of the Delaware, to the north of Cooper’s
creek, a bed is reached having all the characteristics of that at
Burlington and near Spotswood. It is highly astringent, though
when used in moderation it has been found to be serviceable
upon the potato crop. Shells and shark’s teeth are said to have
been found in it, though of this I have not been able to get dis-
tinct information.

LOCALITIES BETWEEN CAMDEN AND SALEM.

Good marl abounds on Big Timber, Woodbury, and Mantua
creeks, within the limits already designated. In the vicinity of
Barnesborough, the proportion of greensand in the stratum gives
it a high degree of fertilizing power. The following analyses
will serve to show its composition in this portion of the tract.

Marl from the farm of Thomas Bee, Esq., Union Cross-
Roads, about five miles southwest of Woodbury, Deptford
township, Gloucester county.

Description.—Colour, rich verdigris green; the washed grains
of a deeper green.
Composition.—In 100 parts:

Greensand, - = - 92-48
Clay, - - - - Coe
Quartzose sand, - - none.

100-00

24

278

The amount of potash in this marl by absolute analysis, is
10-35 per cent.

Marl from the farm of Josiah Heritage, two and a half miles
east of Barnesborough, Gloucester county.

Description.—Colour, dark olive-green; washed granules still
darker, approaching to black; size, rather large.

Composition.—In 100 parts:

Greensand, = = - 93°70
CAG: tote 1d) sow Wha
Quartzose sand, - - none.

100-00

The proportion of potash in this marl, by analysis, is 10-4 per
cent.

Marl from the farm of Joseph Clarke, three quarters of a
mile east of Barnesborough.

Description.—Colour, very dark greenish gray; the washed
grains, quite coarse and of a dark sea-green colour.

Composition.—In 100 parts:

Greensand, = - - 8431
Clay, ee ee ha -69
Quartzose sand, - - 1:00

100-00

The proportion of potash in this marl, by direct analysis, is 9:8
per cent.

Marl from the farm of Mr. Hoffman, one mile and a half
jsrom Barnesborough.

Description.—Colour, rich verdigris green, granular ; washed
grains unchanged.

Composition.—In 100 parts:

Greensand, - - - 85:58
Clay, ent a ee Oe. Sao
Quartzose sand, - - 1-00

279

The proportion of potash in this marl derived by direct ana-
lysis, is 9°5 per cent.

Marl from the farm of John Gaunt, one mile and a quarter
west of Barnesborough.

Description.—Colour, dark gray, somewhat tinged with oxide
of iron; granules large, and when washed of a dull earthy
colour. +

Composition.—In 100 parts:

Greensand, Z = - 82°45
Clay, «Lids &s000 Sugg: Org
Quartzose sand, - - none.

100-00

The proportion of potash deduced from that of the greensand,
is 9-4 per cent.

Marl from the farm of James Jehnes, one mile and a quarter
west of Barnesborough.
Description —Colour, pale yellowish green, somewhat clayey
and cohesive in texture; the washed grains are dark green and
of medium size.

Composition.—In 100 parts:

Greensand, o = = 90:22
Clay, - = - 8:78
Quartzose sand, - E 1:00

100:00

The proportion of potash which this marl contains as deduced
from that in the greensand, is 10-1 per cent.

At Carpenter’s Landing, and about one hundred yards north of
Mantua creek, the blue clay, containing a small proportion of the
green granules and much siliceous sand, displays itself upon the
road where the top of the stratum holds up and discharges the
water. It is seen very generally upon the side of the marl tract
next the river, and may, in nearly every instance, be known by
the water which it throws out, and the astringent impregnations
contained in it.

280

A pretty deep section of the beds belonging to this portion of
the marl region, is beheld in Richard’s Hill, about two miles
north of Mullica Hill. A loose yellowish sand containing a few
of the green grains, and having the depth of about five feet,
occurs on top, being underlaid by about seven feet thickness of
ferruginous sand full of disintegrating shells, casts, and concre-
tions, intermingled with a small amount of the greensand or marl
grains. Below this there occurs a brown ferruginous sand, con-
taining a few of the granules, indistinct casts, and cemented
lumps or concretions of the same with the calcareous matter of
the shells. Beneath all, and nearly at the base of the hill, is a
bed of unmixed ochreous ferruginous sand, very yellow. It has
been dug by the meadow side, and applied to the soil, but with
what good results I know not. By adverting to the section at
Mullica Hill, to be given next, it will be seen, that this last bed is
in all probability the same which lies at the base of the series
there, and that to search, therefore, lower in the earth at this
place for a purer marl than that half way up the hill, would be to
experiment without hope of success, or at least any that could
be justified by our present knowledge of the marl stratum in this
quarter.

About four miles northeast of Mullica Hill, a marl is dug in a
ravine near the road which leads to Woodbury, which is of a
dark green colour, and found to be extremely beneficial upon the
land.

Analysis shows it to possess the following
Composition.—In 100 parts:

Silica, - - 2 : 52:05
Protoxide of iron, - = 23:20
Alumina, - = - 7°50
Potash, - - = - 11:26
Water, - - . - 5:25
Lime, - - - =a traces

99-20

Mullica Hill—At the village of this name, a fine escarpment,
formed by the valley of Raccoon creek, exposes an interesting

series of beds through a height of about forty feet. The upper-

281

most deposit of all, is about six or eight feet of diluvial sand and
gravel. In the descending order the beds are:

1. A light-coloured bright greensand, very free from any
foreign substance, if we except a moderate share of greenish
clay. It has all the aspect of the light-green or upper marl of
many other localities, the efficacy of which has been proved in
some cases to be equal to that of the darker stratum which lies
beneath ; notwithstanding which, the farmers of the vicinity deem
it to be quite inert, and therefore erroneously call it a clay. It is
admitted that very imperfect attempts have been made in using
this material as a manure, and I cannot but believe that a too
precipitate judgment has been passed upon it; for, as the follow-
ing exhibition of its chemical constitution shows, it differs but
little from many marls of long acknowledged efficacy, Its com-
position, it will be seen, does display a less than ordinary propor-
tion of potash.

Analysis of the hght-green Greensand of Mullica Hill.
Composition.—In 100 parts :

Silica, - : : 3 52°32
Protoxide of iron, - - 27°56
Alumina, - = - 8-94
Potash, - : = = 5:50
Water, - - - - 5-42

99°74

2. A chocolate-coloured bed, in which about one half is the
green granular matter and one half a fine clay of a light purple
or chocolate tint. This also has all the features of a good marl,
though it is not reputed to have any power.

3. A thin seam, not more than a foot in thickness, of a dark
bluish-green marl, unquestionably very good.

4. A bed consisting of dark greensand and shells in the state of
casts; the shelly matter being all replaced by oxide of iron.

5. A dark yellow ferruginous sand, with casts of shells and
ferruginous concretions, and a small proportion of the green
granules.

6. A dark yellow ferruginous sand, almost entirely free from
the grains of marl, and containing no trace of organic remains.

24*

282

In the meadows east of Mullica Hill about half a mile, excel-
lent marl is dug from a level many feet higher than the bed of the
stream. As far as the general aspect of the surface enables us to
judge, the position of this bed is lower than the green stratum in
Mullica Hill; but whether they are different horizontal beds, or
one and the same stratum connected by a slight dip to the east,
are points demanding additional research to settle.

The width of the visible marl tract in the neighbourhood of
Mullica Hill, is about three miles.

The several beds seen at Mullica Hill are discernible in the
same relative positions in various places more to the southwest.
At Colston’s, four and a half miles off, the marl is very good.

The analyses which follow will exhibit the character of the
marl in the neighbourhood of Mullica Hill.

Marl from the farm of Isaac Sherman, one mile east of
Mullica Hill.

Description.—Colour, dark-green; the washed grains, small
and of a deeper tint.

Composition.—In 100 parts:

Greensand, - - =) Oe
Cigna ye 763
Quartzose sand, - - 2:00

100:00

The proportion of potash in this marl by analysis, is 9-9 per
cent. .

Marl from the farm of Michael Allen, half a mile north-
east of Mullica Hill.

Description.—Colour, light pea-green; the washed grains, me-
dium size and of a darker green colour.

Composition.—In 100 parts:

Greensand, - - - 96°36
Clay, - - - - 364
Quartzose sand, “ - none.

283

The proportion of potash which this marl contains, as obtained
by analysis, is 12 per cent.
Marl from the estate of William Howe, Mullica Hill.

Description.—Colour, dull verdigris green; the washed grains
of a richer green, and small in size.

Composition.—In 100 parts :

Greensand, -- - - 91:95
Clay, - - - - 8:05
Quartzose sand, - - none.

100:00

The proportion of potash in this marl by actual analysis, is 10-2
per cent.

Marl from the farm of Mr. Jonathan Coulson, one mile
Jrom Mullica Hill.

Description.—Colour, dark grayish-green ; the washed grains,
large in size, and of a deeper green colour.

Composition.—In 100 parts:

Greensand, 2 L 2 86
Clay, - - ° - 11
Quartzose sand, - - - 3

100-00

The proportion of potash in this marl deduced from that in the
greensand, is 9°8 per cent.

Marl from the farm of Josiah Lippincot, one mile south-
southwest of Mullica Hill.

Description.—Colour, dull grayish-green, owing to the presence
of clay; the washed granules dark green, and of medium size.
Composition.—In 100 parts.

Greensand, - - = 89°52
Clay, - - - - 7-88
Quartzose sand, - - 2°60

100-00

284

The proportion of potash deduced from that in the greensand, is
10-2 per cent.

Marl from the farm of Elijah Horner, one mile and a half
southwest of Mullica Hill, Gloucester county.

Description—Colour, rich green, of medium tint; washed
granules dark, and of large size.

Composition.—In 100 parts:

Greensand, - - - 90°75
Clay, - - - - 8:25
Quartzose sand, - - 1:00

100-00

The proportion of potash shown in this marl] by direct analysis,
is 10°8 per cent.

Marl from the farm of John Doull, between Woodstown and
Mullica Hill, three miles from the former.

Description.—Colour, dull earthy green; the washed grains of
a dark green and very small in size.

Composition.—In 100 parts:

Greensand, - = - 89°55
Clays <9) 284 =) a ips
Quartzose sand, - - none.

100:00

The proportion of potash in this marl, deduced from that in the
greensand, is 10:2 per cent.

Woodstown.—The exposed portion of the marl tract opposite
Woodstown is of inconsiderable width, extending from a little
east of the village to about one mile and a half northwest of
Sharptown. In this neighbourhood, the streams cut rather deeply
into the bed, and reveal very nearly the same varieties of the
marl or greensand as at Mullica Hill. Upon Old Man’s creek,
the marl is found as far towards the Delaware as Skulltown,
which indicates a wider expansion of the deposit than might be

285

inferred from confining our observations to the exposure upon
Salem creek. The marl of Skulltown resembles closely that —
which is seen in many other places as we approach the Delaware.

The excavations at Woodstown are very extensive in con-
sequence of the excellent quality of the material and the circum-
stance that this is near the extreme southwestern termination of
the marl tract, or at least of that portion of it which lies at a
sufficient elevation to be of easy access. The features of the
stratum where it is opened in the eastern bank of Salem creek,
are such as belong to a great number of other localities, more
- particularly within the southern half of the marl region.

The beds in the descending order are as follows:

First, the usual covering of diluvium, in which there abounds
a considerable quantity of white quartzose gravel, and near to the
top of the subjacent marl a number of large rounded blocks of a
yellowish sandstone, scarcely calcareous. It is close grained,
and often excessively tough. It has been derived evidently from
a stratum once in place upon the upper surface of the marl, a
portion, I have no doubt, of the bed which still occupies that
position in many places not remote. I see every reason to con-
sider it as representing the stratum known as the siliceous lime-
stone of Mannington, Vincentown, and other points. It seems to
differ from this rock in the relative proportion of the sand and
lime, containing but very little of the latter. At the bridge over
Salem creek about a fourth of a mile to the west of the mar! pits
where these rounded blocks occur, there exists in an undisturbed
condition a stratum of rock in the very position here assumed,
and of a composition and aspect strictly intermediate between
the almost pure limestone, and the above mentioned almost perfect
sandstone. It lies close to the water’s edge, and has therefore
been little noticed. It effervesces pretty actively with an acid,
and has been found when burned in the small way to yield a lime
capable of slaking. It possesses a yellowish-gray hue, showing
the ordinary flinty sand which is its main ingredient, and in
addition, a trivial per centage of the green granules.

The next deposit is the light-green mar], which does not overlie
the dark green in all parts of the bed, being absent in all the exca-
vations nearest the town. In the banks lower down the creek, as
at Mr. White’s, the section exhibits a layer of the light green or

286

upper marl four or five feet thick, resting upon the dark green,
which is here called blue marl, and from which it is occasionally
separated by a crust of cemented ferruginous matter an inch or
two in thickness. Mr. White has applied the material of this
upper stratum to a portion of his soil without any apparent benefit
to the crops, and his sentiment is, that it is destitute of fertilizing
powers. In the pits farther up the creek, where a thin stratum
of it occurs, it is dug and use is made of it, though the farmers
prefer the marl from the darker bed below.

In the banks nearest the town, we behold only the lower marl
penetrated in some places to the depth of fourteen feet, and resting
under the gravelly diluvium, from which it-is parted by a thin
cemented ferruginous crust, a proof of the imperviousness of the
stratum, and the facility with which the water penetrates the
diluvium, and brings down the oxide of iron which it contains.
As the covering of diluvial sand and gravel increases in thickness
in receding from the creek, it is becoming a daily augmenting
obstacle to the uncovering of the marl, rendered more serious by
the copious ingress of water from the marl itself. I take this
place to recommend attention to the advantages to be derived
from the application of some simple machinery, for the purpose
of more effectually elevating the marl and draining the pit, that
it may not be necessary to abandon each excavation at the trivial
depth of ten or twelve feet, and to incur the labour of uncovering
fresh surfaces of the marl bed.

Marl from the farm of Michael Nulls, three miles from
Woodstown.

Description.—Colour, dull green; the washed grains, very fine
and of a very rich sea-green colour.

Composition.—In 100 parts:

Greensand, + = = 83:5

Clay, - - - : 14°5

(Juartzose sand, - . 2:00
100:00

The proportion of potash in this marl deduced from that of the
greensand, is 9-6 per cent.

287

Marl from the farm of Mr. Benjamin Coulson, three miles
Jrom Woodstown, on the road to Mullica Hill.

Description.—Colour, very rich verdigris green ; washed gra-
nules, dark rich olive-green, rather hie in size.

Composition.—In 100 parts:

Greensand, - = - 90
Clay, - - . : 10
(Quartzose sand, - - none.

100

The proportion of potash in this marl by analysis, is 10-1 per
cent.

Marl from the farm of John Dickinson, two miles from
Woodstown.

Description.—Colour, light sea-green; the washed grains, dif.
fering from the original only in their deeper colour.

Composition.—In 100 parts:

Greensand, - - - 92°59
Clay, - - - - 7:41
Quartzose, - - - none.

100-00

The proportion of potash in this marl by direct analysis, is 10-4
per cent.

Marl from the farm of Mr. Allen Wallace, two miles from
Woodstown.

Description.—Colour, dark sea-green; washed granules, still
darker, size rather large.

Composition.—In 100 parts:

Greensand, - - - 90-00
Clay, - - - - 8:00
Quartzose, - - - 2-00

100-00

The proportion of potash which this marl contains by analysis,
is 10°2 per cent.

288

Marl from the farm of Jonathan Cauley, three quarters of
a mile from Woodstown.

Description —Colour, a clear light-green; washed granules, a
little darker; size, large.

Composition.—In 100 parts:

Greensand, - - + 86
Clay, “a = - = 14
Quartzose sand, - - - none.

100

The proportion of potash which analysis shows in this marl, is
10°3 per cent.

Marl from the farm of Elizabeth Borton, two miles north-
east of Woodstown, Gloucester county.

Description.—Colour, dark grayish green; washed granules,
dark-green, of medium size.

Composition.—In 100 parts :

Greensand, - - - 90:13
Clay, - - - - 9:87
Quartzose sand, - - none.

100-00

The potash in this marl deduced from that in the greensand, is
10°3 per cent.

Marl from the farm of Mr. Jonathan Riley, Woodstown.
Description.—Colour, dull greenish gray; the washed grains

of a very rich sea-green colour and very small in size.
Composition.—In 100 parts:

Greensand, - - - 88:28
Clay, - - - - 11°72
Quartzose sand, - - none.
Carbonate of lime, - a trace.

100-00

The proportion of potash, as deduced from the greensand, is
10-1 per cent.

289

Marl from the farm of Mr. Samuel White, Woodstown,

Description.—Colour, light sea-green; the washed grains
coarse and of a dark sea-green colour.
Composition.—In 100 parts:

Greensand, - - - 88:26
Clay, - - : - 8°74.
(uartzose sand, - - 3:00

100-00

The proportion of potash in this marl, by direct analysis, is
10°3 per cent.

Marl from the farm of Mr. Henry Guest, near Skulltown.

Description.—Colour, dull sea-green; the washed grains small
in size and of a dark sea-green colour.
Composition.—In 100 parts:

Greensand, - - - 48-30
Clay,....- - - - 21-47
Quartzose sand, - - 30°23

100:00

The proportion of potash in this marl, as deduced from the
greensand, is 5°5 per cent.

Marl from the farm of Paul Skull, three miles northeast of
Skulltown, Salem county.
Description.—Colour, dull grayish-green; the washed grains
rather large in size and of a deeper green colour.
Composition.—In 100 parts:

Greensand, - L < 91°5
Clay, - - £ - 75
Quartzose sand, - - 1-0

100:0

The proportion of potash contained in this marl, shown by
analysis, is 9 per cent.

In the vicinity of Sharptown, and in two places near Dr.
Swing’s, upon the road from thence to Salem, the marl stratum
is pretty fully exposed, and seems to present almost precisely the

25

290

same succession of beds as seen at Mullica Hill. The upper
stratum invariably consists of little else than the green granules,
their colour being a light verditer green, and on drying rarely
presents the white crust upon the grains seen in the darker sort.
The dark green bed possesses a larger share of dark clay inter-
mingled with the grains, which, according to its hue, imparts
different tints to the stratum. The grains themselves are not of a
very deep green. In Dr. Swing’s neighbourhood, the lower bed
alone is used, under the impression, not based upon experience,
however, that the other is inert. This lower marl has proved
to be highly beneficial, the evidences of which may be seen upon
Dr. Swing’s farm. Yet this lower bed is apparently identical in
all respects with the lower stratum at Mullica Hill, where it is
pronounced equally inefficient with the upper. This fact ought
to show us how many experiments remain to be made before we
ean pass a final judgment upon the non-existence of fertilizing
properties in any of these marls. ‘The lower bed here contains
but few shells. At Woodstown there is one layer containing a
prodigious abundance of the gryphed convexa, ‘and a less propor-
tion of one or two other species. Sharks’ teeth, and the bones of
the fossil crocodile are not uncommon. The shells possess but a
small amount of lime, much of it having been dissolved away,
and its place supplied by oxide of iron, from which they derive
their brown ferruginous colour. Their presence is therefore of
little or no benefit to the marl. |

Marl from the farm of Dr. Swing, near Sharptown.

Description.—Colour, dark earthy-green; the washed grains
of the same colour, and large’ in size.
Composition.—In 100 parts:

Greensand, - - - 91-20
Clay ete 2 Nie Nae 8:80
Quartzose sand, - - none.

100:00 -

Potash, by direct examination, 10 per cent.

Four miles to the southwest of Sharptown, the surface of the
country suddenly drops twenty-five feet, or more, toa lower level

291

forming an extensive plain, characterized by a clayey soil, and
noted in this section of the State for its greater relative fer-
tility. The same tract borders, in a belt a few miles in width, the
Delaware river and bay, to Cape May. Throughout the whole
of this area, in consequence of the very small elevation of the
surface above the tide, the marl stratum is scarcely once in-
tersected by ravines or streams; though I entertain but little
doubt that it spreads itself in the southwest direction to the De-
laware. At Joseph Bassett’s, about four miles from Salem, the
marl may be seen at a small depth beneath the surface. It re-
sembles in all respects that which is generally the lower stratum;
containing the same gnixture of clay, the same shells, and having
the same white efllorescence. ‘The principal fossils are gryphea
convexra, exogyra costata, ostrea falcata, and several spiral uni-
valves in the state of casts, finely preserved, from which we may
justly infer that the stratum is not very wet. Teeth and bones
also occur.

Marl from the farm of Joseph Bassett, north side of Branch.

Description.—Colour, dirty-green, unchanged by washing.
Composition.—In 100 parts:

Greensand, - : - 89-81
Clay, - : - = 5:19
Quartzose sand, - = 5-00

100.00

The proportion of potash in this marl, deduced from that in the
greensand, is 10°3 per cent.

Marl from the farm of James Smith, Mannington Fill,
Salem county.
Description—Colour, rather green, of average depth of tint;
the washed greensand is of a rich dark green.
Composition.—In 100 parts :

Greensand, - - - 88-80
Clay, - - - - 10-20
Quartzose sand, - - 1-00

100-00

292

The proportion of potash which this marl contains, by direct
analysis, is 9°5 per cent.

Marl from the farm of Woodnut Petit, near Mannington
Fill, Salem county.

Description.—Colour, light yellowish-green; washed granules
dark-green, of medium size.

Composition.—In 100 parts:

Greensand, - - - 77°15
Clay, - - - - 18°35
Quartzose sand, - - 4:50
gee
100-00

The proportion of potash in this marl, eure from that in the
greensand, is 8°8 per cent.

I have thus brought my observations as far to the southwest
as any traces of the marl stratum show themselves. The chief
object of the numerous details here given is to furnish hints,
possibly of some future advantage to the several neighbourhoods
specified, and moreover to awaken in each district a spirit of
inquiry and experiment, which, should it ever be aroused to vi-
gorous activity, must sooner or later be productive of the greatest
benefits to the whole marl region, and to the State at large.

CHAPTER IL.
DISTRICT SOUTHEAST OF THE MARL TRACT.

Tue physical features of the extensive sandy plain which
reaches from the southeastern margin of the greensand, almost
to the seacoast, have already been described. It only remains
for me to detail a few points in its geology of a chiefly practical
bearing. These are some small tracts of tertiary calcareous marl,
its numerous deposits of bog iron ore, and the extensive stratum
of white glass-maker’s sand, with which its surface is covered.

293

SECTION I.

Tertiary Calcareous Marls.

These are highly interesting in a twofold point of view: first, in
reference to our agriculture, as occurring in the midst of a region
of sandy soils where the greensand marly lime, and other like
sources of fertility are remote; and secondly, in reference to the
progress of our scientific geology, from being the only terteary
formations yet discovered in the State, and at the same time the
extreme northeastern limit of the very extensive range of the

. tertiary deposits of the Atlantic border of the middle and southern
States.

The geology of these beds is at present somewhat obscure,
though the few fossils found prove that they belong to one of the
oldest periods of our tertiary formations. Their range is very
circumscribed, the only locality of much importance being near
the western corner of Cumberland county. Nevertheless, the
deposit demands a brief description from its economical value to
the neighbourhood where it occurs, and the clew which it may
furnish to corresponding strata in other sections of the sea-
board region of the State.

These small insulated patches of tertiary, are evidently refer-
able by their fossils to the miocene epoch, notwithstanding the
disproportion of extinct over recent species. We can at present
enumerate only about thirteen clearly recognized species; twelve
of which are no longer in existence. Though this proportion
might rather imply an eocene date for the deposit, the number of
discovered fossils is too few to justify us in concluding this to be
the actual relation of the extinct to the recent shells; while on
the other hand, all the species are either identical with those of
the miocene of Maryland and Virginia, or exhibit a close analogy
of form.

The position of the principal known tracts of tertiary in the
State, will be seen by consulting the geological map.

The principal deposit of these tertiary marls occurs in Cum-
berland county, upon the upper part of Stow creek and its tribu-
taries, but whether it extends farther through the country, con-

25*

294

cealed by the superficial sands, or, what is rather more likely,
occupies what was originally a cove or bay in the midst of the
adjacent secondary strata, are points still obscure. At Elwell’s
pits, about two miles northwest of Roadstown, the deposit shows
the following features :

The superficial stratum of the neighbourhood is a rather coarse
yellow sand, five or six feet thick in the bank where the marl is
excavated. Beneath this, there is a layer four or five feet thick,
of a reddish-yellow clay, abounding in traces more or less obscure
of fossil shells in an extremely rotten and decayed condition,
Beneath this there is a bluish-green clay containing a multitude
of the same fossils in a somewhat less decomposed state, though.
very soft and tender. These two fossiliferous beds are in some
places twelve feet thick, and rest upon a dark greenish-blue
adhesive sand, bearing a close resemblance to the tenacious
sandy clay of the greensand formation. In the adjacent bank it
has the prevailing colour of that bed, and the same astringent
substances (copperas, &c.) which characterize it so generally.
The mass of loose friable clay, both yellow and green, exhibits a
very considerable proportion of carbonate of lime derived from
the decomposition of the shells, and the calcareous matter of
these fossils themselves. It is a marl calculated to be especially
beneficial upon the very sandy land of the vicinity. It will be
found valuable as a fertilizer in proportion to the lime which it
contains, the crumbly state of the shells, and its freedom from
sand.

The description here given of Elwell’s marl, will apply pretty
well to the other marls excavated upon the same streams, with
this reservation however, that the shells in some localities are
less rotten and in their nature less destructible, which is the case
with those of the oyster. These occur in one part of the deposit
at Davis’s bank; and also in the greater number of the openings
higher up the stream, where the clay seems to possess a rather
larger share of sand.

Another stratum of the same geological age, occurs about a
mile and a half southeast of Fairton, and near the Rattlesnake
run. It isa very thin bed of a similar bluish clay, containing a
small proportion of decomposed shells, and resting, like the Stow

295

creek marl, upon the same astringent argillaceous sand. It also
is of two varieties, one containing only oyster shells and much
sand: the other being more clayey, and possessing a larger
amount of calcareous matter, and the fossils in a very decayed
state. The deposit here has not been much developed, though it
obviously deserves to be zealously explored.

Much of the value of a marl of this description depends upon
the condition of the shells which furnish the lime. These may
be very indestructible, the case most generally with the oyster ;
or on the contrary so easily decomposed, as to be found generally
in that chalky and decayed state necessary to constitute a good
marl. The largest, and at the same time one of the most
abundant fossils in the Stow creek marl, is the Perna maziillata,
a thick, flat, pearly shell, dividing into numerous -thin scales, and
valuable from the readiness with which it decays and distributes
its calcareous particles.

In excavating marl in this neighbourhood, it is all important to
avoid mixing with the calcareous stratum any of the astringent
matter which lies immediately beneath. This is noxious to the
crop and seriously detrimental to the soil. It will be known by
its taste, and its rarely containing fossils.

I have accompanied this account with the following analyses
of these marls, for the purpose of ascertaining for the inhabitants
of the quarter interested, the relative efficacy of different spe-
cimens from several localities.

1. A specimen of average richness from the marl pits of Mr.
Elwell, yielded

Lime, - 2 : - 25:5 ) Carbonate of lime 45:5
Carbonic acid, - - 20-0 per cent.
Greenish residue, chiefly clay,
with some oxide of iron, 54:0
Loss, - - “ - 00°5
100°0

The shells in a very rotten chalky state, principally Pernas,
and a good many small turrited univalves.

296

2. A specimen of the better variety in Mr. Davis’s pits, afforded
iime,.\ = = - = 20-6 Carbonate of lime 36:8
Carbonic acid, - - 16:2 per cent.

Greenish residue, clay and sand
containing some oxide of iren, 63-0
Loss, —- - - - 00-2
100-0

The shelly matter much decayed, consisting chiefly of Pernas

and Turritella.

3. The Fairton marl affords from the best variety

Linte,<x'= - = = 19-0 ) Carbonate of lime 34
Carbonic acid, ¥ - 15-0 per cent.
Greenish residue of clay and
sand, - - - - 65°5
Loss, - - - - 00:5
100:0

The shelly matter fragments of Perna.

The inferior variety, consisting of sand with a little clay and
shells belonging to a species of oyster in an undecayed condition,
contained, in two examinations made, not more than four per
cent. of carbonate of lime, after the shells were picked out.

Bog Iron Ores.—This district is characterized by an abundant
supply of bog iron ore, which sustains in fact a principal part of
its manufacturing industry.

The origin of the deposits of bog ore of the region before us,
we can readily understand, by adverting to the very ferruginous
nature of nearly all the strata, both the greensand and the beds
overlying it. ‘The water, not only in the marl region proper, but
throughout the adjacent tracts, contains very generally a consi-
derable quantity of the oxide of iron, which it procures in its
passage through the upper strata. Upon coming into the open
air it parts with the carbonic acid, the agent by which it is en-
abled to retain the oxide of iron in the dissolved state; this it
quickly precipitates, and hence the accumulations of bog ore in
all situations where the low grounds are entered by springs

297

passing out of the more ferruginous beds of sand and clay. As
some of these, the marl stratum for instance, contain a notable
proportion of the phosphate of iron, we discover whence the bog
ore is contaminated with phosphoric acid, producing a cold short
iron. The source of the ore accounts for the interesting fact that,
after being dug, the deposit is again renewed after a series of
years. In some places, the requisite period does not exceed
twenty years. It is essential to the continual deposition of the
ore, that the soil in which it is precipitated should not be drained,
but that it should be incessantly washed by the ferruginous
springs. Where the water from these is enabled readily to
escape, and the surface of the ore laid bare and exposed to the
rains, the oxide of iron vanishes almost as rapidly as it before
accumulated. The lumps retain, it is true, the cellular struc-
ture of bog ore, but the matter left consists almost entirely of the
more earthy portions, from the solvent power of rain water for
oxide of iron in the loosely cohering state in which it exists in
the ore. The rain water seems to owe its capacity of dissolving
the iron in the ore to the small quantity of carbonic acid which
it collects in its passage through the atmosphere.

We derive one important hint from these facts: namely, that
those who make use of this variety of ore, should avoid keeping
large accumulations exposed to the weather as we so frequently
witness at the furnaces in the section of the State where the bog
ore abounds. It should be dug, in fact, only as it is needed.

The map accompanying this report, will exhibit the general
limits of the several tracts of bog ore, both those confined to the
greensand region, and those of far greater extent which occur in
the wide sandy country lying between it and the ocean. While
the areas represented on the map embrace all the deposits of
magnitude and importance, they are not to be regarded as con-
taining the bog ore throughout every portion of their surface.
On the contrary, the mineral lies principally along the borders of
the main streams and their tributaries, and in the beds of those
extensive swamps and wet meadows, with which, owing to the
sluggishness of their waters, they are generally surrounded.

Two great deposits, incomparably the largest in the State,
border the principal tributaries of the Little Egg Harbour river.
The most western of these is connected with the waters of

298

Atsion river and most of its branches, extendinz from near the
sources of these streams in a tolerably wide belt southeastward
to Landing creek. The length of the tract within which the bog
ore is found on nearly all the tributaries, is about twenty miles,
while we may state its average breadth at three miles. The
other, or eastern tract, lies along the Tulpehaukin or Wading
river, and its several branches. It covers an area quite as exten-
sive as the former, but the deposit of ore in this latter district is
greatly inferior in abundance to that on the Atsion river, particu-
larly in the neig'\bourhood of Atsion iron works.

The several minor deposits of bog ore are confined to the
limits of the marl region.

One of these occurs on Talman’s creek, a small tributary to
the Rancocus; another is found upon the south branch of the
Rancocus near its junction with the north branch; and another
lies on the Manasquan river, near the little village called Georgia,
in Monmouth county. Other similar deposits are met with on
the Manalapan and Machaponix creeks, in Monmouth county, two
small tributaries of the South river, which flows into the Raritan.

The usual features of the beds of bog ore, their probable origin,
and the peculiarities in the structure of the ore itself, will be
understood by the following description of those which occur in
the vicinity of Atsion iron works, which may be regarded as
representing those deposits generally.

The Atsion river takes its origin within a mile of Long-
acoming, In the greater part of its course, it flows through ex-
tensive flats or cedar swamps, the water becoming in its passage
through these, highly tinged with vegetable matter.

Near to the source of this stream, and at numerous other
places along its course, the sand, though of a snowy whiteness on
the surface, presents a ferruginous tinge wherever the inferior
layers are to be seen. The water oozing from these sands,
carries with it more or less of the oxide of iron, derived evidently
from the upper and more exposed parts of the stratum, depositing
it as it reaches the air,

Within two miles of the source of the Atsion, bog ore is found,
though not in very considerable quantity.

The ores which are used at the Atsion works, are obtained
from above the furnace, the present excavations are chiefly at

299

about three or four miles above the pond or dam which supplies
the water power. Great quantities of the ore are also taken
from the bed of the pond during the winter, when the furnace is
out of blast and the water is drained off. The ores which are
used at this furnace are, the Joam ore, the seed ore, and the massive
ore. ‘The swamps of the river (which is rather sluggish) are
extensive, and form numerous shallow coves, some of which are
covered with water to the depth of about a foot, while others
contain a very spongy peat, which is always found on the edges.
The ore is chiefly taken from these coves when the water is not
too deep, especially along their wet margins. Excavations eight
or ten feet square are made, between each of these a thin dike is
left, so as to prevent the water from one flowing in upon the
workmen in the others. The three kinds of ores are generally
found in each hole; the loam ore nearest the surface, the seed
ore under this, and the massive ore at the bottom. In some
positions, however, only one of these kinds occurs, unaccompanied
by the others. In other positions, the several varieties may be
seen in their various stages of maturity. The loam ore is that
which appears to form first, being in reality merely the infiltra-
tion of ferruginous sediment into the soil of the bog. This, which
is at first quite soft, becomes by the accumulation of oxide of
iron, heavier and more compact. In the centre of many lumps,
the mass has a crystalline or regular ore-like character. This
structure would pervade the whole deposit, could it be exposed
for a sufficient length of time to the correcting action. The loam
is thus in time completely replaced by the oxide of iron, which
is seldom solid, but of a honeycomb structure, the cavities being
more or less filled with yellow aluminous matter. These ores
are obtained in various conditions of compactness. That which
is partly concreted, partly pulverulent or loamy, is called young
ore, a variety which experience shows to be better adapted for
easy fusion, than the more concretionary harder kinds.

Great quantities of woody matter, such as stumps and trunks
of trees, abound in these ore beds, completely converted into
oxide of iron. The curious process of replacement which has
taken place, has preserved the precise form and structure of the
bark and woody fibre, down to the most delicate lines and
markings.

300

Anailyses.—The following analyses will display the composition
of the bog ore, in its ordinary varieties.

Bog Ore.—Atsion Iron Works.

Description.—V ariety called seed ore.
Composition.—In 100 parts:

Peroxide of iron, - E 66°10
Alumina, - ~ : 66
Insoluble matter, - : 20°53
Water, - - - 12°54

99°83

The metallic iron in this ore amounts to 45:83 per cent.

Bog Ore.—Atsion.

Description.—Concreted, cellular; taken freshly from the bog.
Composition.—In 100 parts:

Peroxide of iron, - ‘ 68-90
Alumina, - - - 2°37
Insoluble matter, = - - 13-99
Water, - - - 14:04

99-30

The metallic tron amounts to 47-71 per cent.

Bog Ore.— Upper Squankum.

Description.—Concreted, cellular.
Composition.—In 100 parts:

Peroxide of iron, - - 76°35
Alumina, - - 4 0:23
Insoluble matter, - = 9°29
Water, s : “ 12°76

98:63

The amount of metallic iron is 52-94 per cent.

301

Bog Ore.—Shrewsbury river, near Eatontown.

Description.—Concreted, cellular.
Composition.—In 100 parts :

Peroxide of iron, - . 67°78
Alumina, - - - a trace.
Insoluble matter, - E 18°54.
Water, - - - 8:69
Organic matter and loss, 4-99

100:00

The amount of metallic aron in this ore is 46:98 per cent.

White Sand for Glass Making.

Upon the Maurice river, about three miles below Millville,
in Cumberland county, an important locality occurs, which fur-
nishes this valuable material in great abundance. This deposit
of sand presents a number of layers, more or less approximating
to absolute purity ; but previous to its being employed in the glass-
house, it is always necessary to submit it to a careful washing,
in order to discharge a small quantity of yellowish and slightly
ferruginous clay, with which it is intermingled in the bank.
After the washing it is a pure transparent quartzose sand, the
grains of which are small and of very uniform size. There are
five glass-houses in the vicinity of Millville, besides many at a
distance, which are supplied with sand from this spot. Numerous
other places throughout the very sandy district before us, yield a
material equally good, but scarcely any other point yet explored
offers the same readiness of access.

In the neighbourhood of Mount Hope much good sand is
found ; it is used at the Windslow and several other glass works.
The sand used at the Waterford glass works is procured in the
vicinity of that establishment.

Within two miles of the Brooklin glass works good sand is
procured, and is employed both in these and in the Squankum
works.

The neighbourhood of Jackson’s glass works furnishes a sand
well adapted for the manufacture of both window and _ bottle
glass.

FINIS.

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