REPORT
GEOLOGICAL RECONNOISSANCE
“ THE

STATE OF VIRGINIA.

MADE UNDER THE APPOINTMENT OF THE BOARD OF PUBLIC WORKs.

PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF VIRGINIA.

PHILADELPHIA:
, ALAA

DESILVER, THOMAS & CO.
1836.

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REPORT.

GENTLEMEN,
I beg leave to present the following report of the geo-

logical reconnoissance of the state of Virginia, authorized by an act
of the legislature, bearing date March 6th, 1835, with the execution
of which I have had the honour to be entrusted.

In the prosecution of this duty, while my attention has not been
withheld from such observations of a minute and detailed descrip-
tion as opportunities occasionally threw in my way, it has been
chiefly directed to the legitimate objects of such a reconnoissance,
namely, the general geological and mineralogical features of all the
important divisions of our territory, with a view to exhibit the
benefits to be derived from a detailed survey, and the mode of con-
ducting it best adapted to develop the structure and resources of
the state, Although in the course of these inquiries many new ob-
servations have been made calculated to prove extensively advan-
tageous, numerous matured discoveries were not to be anticipated,
considering either the design of the reconnoissance or the very
general nature of the investigations which are appropriate to an
examination strictly preliminary in its character. Inquiries of a
more minute description, extended to all the divisions of the state,
would obviously have been impossible, and until some scheme
of systematic investigation in detail is put in operation, compara-
tively of little value. With such views, it is thought that the objects
of the reconnoissance are accomplished, in exhibiting the prominent
geological features of the great divisions of the state, the more im-
portant natural resources dependent upon their mineral structure,
and in pointing out in relation to each the various desiderata to
which future inquiry may be beneficially directed.

MODE OF CONDUCTING THE RECONNOISSANCE.

With the view of exhibiting clearly the geological structure and
Yelative extent of the various formations in the state, as far as ascer-

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tained during this reconnoissance, it was important to construct
what is termed a geological section or profile, from actual observa-
tions made from point to point in one or more lines transverse to the
general ranges of the strata; thus combining in one view, all the
most important mineral formations of the state, together with their
prevailing order of succession, and their relative inclinations, or the
angle in which each inclines to the horizon. The general line of ob-
servation selected for this purpose, extends from Hampton Roads to
the mouth of Guyandotte. A belt of country of variable breadth,
spreading to some distance on either side of this line, was the more
immediate subject of investigation, and furnished the materials from
which the geological section appended to the present report was
constructed.

In prosecuting the examinations necessary for this purpose, no
one line of observation was rigorously adhered to, but numerous
local profiles were first formed, and thence by a reference of them
all to the general line already specified, the entire profile was formed,
which is now presented. It is, therefore, tendered at this time only
as an approximate delineation of a transverse geological section of
the state, and as such, though sufficiently accurate for the purposes
of occasional reference in the present report, lays no claim to the
minute precision of geological profiles constructed from the accurate
data of a detailed survey. Several minor belts also transverse to
the general ranges of strata, and remote from the former, were like-
wise examined, and particular profiles constructed from the data
thus obtained. One of these extends in a general direction from
the White Sulphur springs, by Covington and Lexington to Bucking-
ham courthouse; a second from Columbia, by ee da
and Rhodes’ gap, and Harrisonburg, to the North mountain; and a
third embraces a portion of the Potomac. In addition to these
transverse lines of observation, several routes have been explored
more nearly conforming to the bearing or direction of the strata.
One of these extends in a general direction from Halifax, on the
Roanoke, to the lower falls of the Potomac, and is nearly coin-
cident with the western boundary of the tide water or tertiary
section of the state. Another embraces a general view in the
longitudinal direction of the valley of Virginia, from the Potomac to
the James river, &c. Beside these, many other lines of ‘observation
were examined, some of them embracing a distance of 50 or 60
miles, on either side of the general route. Keeping in view the im-

SRR IT co perc

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portant practical inquiries appertaining to the reconnoissance, as
much local information of a useful nature has been obtained on each
excursion, as was consistent with the time which could be devoted
to investigations of a special character. The general nature of the
observations contemplated in the reconnoissance, and the necessity
of rapid movements when so great a breadth of formations was to
be traversed, rendered much delay in minute local observations in-
expedient, on which account many points of great practical interest
: will be excluded from the report, which might otherwise have been
introduced. These would be among the proper subjects for inquiry
in a detailed survey.
| In regard to the tide water section of the state, it is proper to
| remark, that through some previous attention to its geology, I am
enabled to present a somewhat minute account of its important
features, as observed in several large and interesting districts which
I have explored. Among which, I would specify the peninsula
bounded by the York and James rivers, and many of the counties
on either side. More recently, and in connexion with the recon-
noissance, I have examined the country on both sides of the Pamun-
key, from the junction of the North and South Anna to its mouth,
and have extended my inquiries with some success into similar
formations south and north as far as the James river and the Potomac.
The discovery of a material likely to prove valuable to the agricul-
ture of that section of the state, may, without impropriety, be re-
ferred to as an illustration of the utility to be expected from minute
geological inquiries, directed to every portion of our territory.

But in addition to the duty of exploration performed according to
the plan which I have now described, I have devoted some time to
_ “the chemical analysis of rocks, ores, earths, marls and mineral
waters. In relation to this department of my duties, however, it is
easy to perceive, that the tedious nature of such investigations,
would preclude the completion of many accurate analyses within the
period allotted to the reconnoissance; but a variety of useful che-
mical results have been obtained, which as far as compatible with
the scope and objects of this report will be detailed in the following

pages.

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ETS ET RNR INT

Ai

LBNERAL GEOLOGICAL DIVISION OF THE STATE.

_ For the sake of exhibiting under one view, each group of analo-
gous formations, the whole territory of the state may be conveniently

8

divided into five principal regions. These we will treat of in a geo.
graphical rather than geological order; first defining the limits of
each respectively, with as much precision as in the imperfect state
_ of knowledge on the subject can be attained, and then in general
terms describing the geological features by which they are, to a cer-
tain extent, severally distinguished.

(1.)—The first of these, which may be called the tertiary marl re-
gion, embraces nearly all that portion of the state included between
its eastern boundary, the Chesapeake bay and the’ Atlantic, and a
hypothetical line intersecting the principal rivers at their lowest falls.
Various beds of clay and sand, nearly horizontal in position, abound-
ing in fossil shells, and the remains of large marine animals, form
the characteristic strata of this division of the state, while occasional
bands of iron ore, and beds of green sand, and a small portion of
gypsum, occurring in connexion with one of the fossiliferous -de-
posites of the region, are among its other materials of value.

(2.)—The second division is comprised between the hypothetical r
line above mentioned and the western flank of the Blue Ridge—in-
cluding under this title the range very improperly denominated the
Alleghany mountain in Franklin and Patrick counties. According ;
to the delineation of Mr. M’Clure, by whom the first attempt was
made at marking out the great geological divisions of North America,
the rocks of the Blue Ridge and a narrow adjacent belt of territory
should be regarded as belonging to the primary system of geologists
—while a large portion of the area between this and the belt of yn-
equivocally primary character which ranges along the lower falls of
our rivers on the east, is to be looked upon as the equivalent of the
old red sandstone rocks of Europe, Others who have attempted to
sketch the outlines of our principal geological forma have witli r
even less approach to accuracy, confounded all these strata under
the sweeping denomination of primary—and have thus given to the |
diversified and extensive region whose limits are above described, i
the distinctive appellation of the primary region of Virginia, Such '

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a view appears to have been adopted by the authors of the map of
our state, the brief geological sketch appended to which describes
the Blue Ridge as the western boundary of the primary. A more
recent writer also, professing to derive his views from an actual «t
examination of the structure of this mountain, has contributed to —
confirm the prevailing error by proposing as an appropriate name for
the Blue Ridge—the title of the Atlantic primary chain. It is deeply

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“to be regretted that while so little has been done towards a minute
exploration of the diversified and complex formations of the region
now in question, the writers who have attempted to describe it, and
more especially those who have professed to give a scientific exposi-
tion of its character, should have observed so little caution in the
application of names, and have indulged so much of the spirit of
superficial and precipitate generalization. There is no division of
the state which presents greater difficulties to the geological inquirer,
than the region here referred to, and none which will require for its
elucidation more minute and patient investigation. The observa-
tions respecting some parts of it, which will be presented in the body
of the report, imperfect as they necessarily have been, were directed
in part to the determination of some of the difficult problems which this
portion of our geology presents—and although insufficient to re-
move the difficulties in which the subject is involved, will, it is be-
lieved, lead to several interesting and important views of a scientific
as well as practical nature, while they overthrow the errors which,
either through ignorance or inadequate investigation, have hitherto
existed. So far from regarding the whole area in question as of a
primary character, these observations conclusively demonstrate that
the extent of the rocks, to which that title may be unequivocally ap-
plied, bears but a small proportion to the whole surface of this divi-
sion of the state—and while they render it doubtful whether in the
Blue Ridge any truly primary rocks occur, they evince the existence
in that range, as well as throughout a very extensive district to the
east, of sandstones, conglomerates, and other sedimentary deposites,
unquestionably referable to a different period of formation.

The gold region, so remarkable for its extent and richness, and
the bituminous coal fields of Chesterfield, Goochland, Powhatan and
Prince Edward, constitute important divisions of this region of the
state, while the slates and soapstones, iron ores, limestones, and
other minerals which it includes, are objects of practical as well as
scientific interest. To all of these a proper place will be allotted in
the body of the report.

(3.)—Our third genera] division, commencing near the western flank
of the Blue Ridge, comprises all the region generally called the Valley,
extending westward in the counties of Berkeley, Frederick, Shenan-
doah and Rockingham, to the base of the several ranges called the Lit-
tle North mountain, in Augusta and Rockbridge, nearly to the base
of the North mountain, and in the counties further south, occupying

2

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an area, which, for the present, does not admit of being accurately
defined. Limestone strata of vast extent, hydraulic lime, marble,
travertine or deposite marl, slate, iron ore, and in the south, lead ore,
are among the valuable materials included in this section of the
state. Declining to apply the title of Z’ransition to the strata of
which this region is composed, because much additional observation
is required for the determination of their true geological relations,
we must for the present be content with referring them to the oldest
of that group of rocks in which the organic remains or fossils have
been discovered.

(4.:\—The fourth general division to which we shall refer is, at
present, even less susceptible than the preceding, of being defined by
lines of precise limitation. Nearly the whole of its surface is occu-
pied by chains of mountains, and extremely little has hitherto been
done towards exploring its geology. In general, it may be described
as comprised between the western limits of the great valley forma-
tion and the front ridge of the Alleghany, the Greenbrier and Muddy
creek mountains ; but with regard to its extent and boundaries fur-
ther south, nothing definite can be affirmed until it shall have been
carefully and systematically explored. Besides the interest in a
scientific point of view which attaches to this region, on account of
the peculiar structure of its mountains, the stupendous natural sec-
tions which it exposes, and the astonishing abundance and variety
of the fossil impressions found among its rocks, it claims a high
importance from the great value of its materials, economically consi-
dered. Its anthracite, pseudo-anthracite, or semi-bituminous and
bituminous coals, its limestones, sandstones and grits, and iron ores,
and its numerous thermal, chalybeate and sulphuretted springs, con-
stitute collectively an amount of mineral treasures of which few
other territories of the same extent are as largely possessed. With-
out, at present, venturing to apply any precise geological designa-
tion to this singularly interesting region, it will be shown to have
marked peculiarities which distinguish it from the division pre-
viously described.

(5.)—Our fifth and last division, stretching from the eastern limits
of the former to the western and south-western boundaries of the
state, presents an area of vast extent, and embraces regions abound-
ing in materials of the highest economical utility.

This immense territory, characterised by nearly horizontal strata,
gently dipping towards the west refers itself unequivocally to the

1]

group of secondary rocks—and from the numerous and rich beds of
bituminous coal which it includes, may with strict propriety be de-
nominated the great secondary bituminous coal region of Virginia.
Besides its numerous and widely stretching strata of the above-
mentioned material, this favoured region possesses the additional
treasure of a saline formation of immense extent, towards its western
boundary—and if the limits of the region are not improperly as-
signed, a similar formation, accompanied with gypsum and other
valuable minerals in the south-west corner of the state.

(6.)—Pursuing the order in which the several divisions of the state
have now been sketched, the Tertiary marl region will first claim
our attention.

TERTIARY MARL REGION.

The extensive area embraced in this division of the state, though
presenting comparatively little diversity in external aspect, includes
strata, which, by their fossil contents, unequivocally refer themselves
to two distinct geological periods, though they are all without doubt
comprised in the general class of tertiary formations. Adopting the
names which have been recently applied in Europe to parts of the
tertiary series, to which the strata referred to may be regarded as
probably equivalent, though without implying any conviction on our
part, that such equivalence is in general to be expected in the two
continents, we shall indicate by the term Miocene the strata which
occur in the eastern and greater portion of this region, and from
which the ordinary shell marl is procured, while we will apply the
name Locene to the deposit of an older date existing beneath and
west of the preceding, containing fossils of a different character, and
characterised by the prevalence in considerable proportion of the
peculiar mineral called green sand.

The first of these, or the Miocene marl district, comprehends all
the area from the seaboard or water boundary of the state on the
east, to a line conceived to be drawn through Northbury on the Pa-
munkey, and Croggin’s point on the James river, in a direction
nearly meridional, but through what precise points, further observa-
tions are necessary to determine.

The other or Eocene marl district is comprehended between the
imaginary line above described and another line passing from the
mouth of Acquia creek, through Wales, at the junction of North and

12

South Anna rivers, and thence through City Point, and further south
in a direction not yet precisely ascertained. Much of the district
here defined exhibits Miocene as well as Eocene marl, the former
being found either in highlands remote from the rivers, or in the
superior parts of the-river cliffs overlying the latter. The localities
above named were selected as points marking the eastern boundary
of this region, because at those places the Eocene marle was ob-
served to disappear below the water line by a gentle dip to the east.
Its existence extensively beneath the Miocene district may be looked
upon as highly probable, though under what circumstances as to
depth and inclination of the beds, we have no positive data to deter-
mine.

MIOCENE MARL DISTRICT.

In the most eastern portion of this division of the tertiary, the
general level of the surface is but little elevated above tide. The
country is a uniform flat, in some places subject to be occasionally
overflowed. The rest of the region in question has an elevation
above tide, varying from twenty to eighty feet. But few points,
however, in the district have a level corresponding to either of these
extremes, and by far the larger portion of the surface preserves a
height of from forty to fifty feet.

The surface of this more elevated portion, though preserving a
general level of remarkable uniformity, is deeply channelled by innu-
merable ravines. The smaller of these connect themselves with
large ones, and these with the wider and deeper excavations forming
the beds of the creeks flowing into the neighbouring rivers. The
system of ravines connected with one river are separated by a nar-
row central tract from those connected with the next, and in a gene-
ral view of the district, these systems present the appearance of
mere creeks or inlets subordinate to the great rivers by which this
region is broken into peninsulas. The number and extent of the
large rivers and the navigable streams of this portion of the
state, constitute the most inestimable of its natural advantages.
The numerous creeks indenting its peninsulas furnish the cheap-
est and readiest avenues for a commerce which comes home to
the abodes even of its rural inhabitants, while its surface scooped
into ravines and its river cliffs washed by the tides, disclose the
rich materials which are hereafter to bestow the highest rewards

13

upon its enterprise, by spreading fertility and wealth to its remotest
boundaries.

The superficial stratum of the region we are describing is an
argillaceous and ferruginous sand of a yellow and sometimes of a
reddish colour, in which are occasionally found at or near the sur-
face, pebbles and small boulders of sandstone, rarely as much as six
inches in diameter. The nature of these boulders would indicate
that they were most probably derived from the sandstone formation
which ranges along the eastern boundary of the primary ridge. In
some places this stratum consists of little else than a white silicious
sand; in others, the admixture of ochreous clay is so considerable
as to furnish a suitable material for the manufacture of bricks.

Beneath this superficial layer, beds of a very argillaceous clay
occasionally occur, sometimes of considerable depth and extent, and
ofa texture to be useful in puddling. Its colour is various, being in
some places a dark blue or green, in others a bright red or dingy
yellow. Wherever found, its upper boundary is remarkably even
and horizontal; but where it rests upon beds of fossil shells, its
lower limit conforms to all the irregularities of surface which those
beds usually present. Its appearance, in some places, is that of a
steep, almost perpendicular wall of smooth surface, and divided by
very narrow lines running horizontally. These narrow lines, at a
distance of from five inches to a foot asunder, are formed by a more
ferruginous and silicious clay. At Bellefield, on the York river,
seven miles from Williamsburg, this deposite may be seen overlying
the stratum containing shells, in some places having a thickness of
from twelve to fifteen feet, and then gradually fining out and passing
into a light coloured and coarser mass. The upper surface is hori-
zontal, and the lines of division above alluded to are perfectly paral-
lel and regular. The lower surface of the clay conforms to that of
the shell stratum upon which it rests. In many places these argilla-
ceous beds consist of a yellowish clay, beautifully variegated by
streaks of red and blue. In some places there exists a slight impreg-
nation of alum and copperas in these beds of clay. This is particu-
larly the case in some localities on the Rappahannock and the York
and Chickahominy rivers. The proportion of these ingredients is,
however, not sufficiently great to entitle these strata to attention in
an economical point of view, although it is fully sufficient to impart
a very ungrateful flavour, and perhaps some useful medicinal pro-
perties to the springs and wells of the neighbourhood.

14

A thin stratum of red ferruginous stone, containing a large propor-
tion of oxide of iron, is found in this region, running horizontally
below, and sometimes in the beds of clay before described, and ge-
nerally separated by only a few feet from the underlying masses of
shells. This stratum, which is very generally present, varies in
thickness from an inch to a foot. Its texture is sometimes cellular,
sometimes compact and fibrous, like that of certain varieties of he-
matite. In the more eastern portions of the Miocene district, the
peculiar structure of which will be hereafter described, much ore of
this description lies loosely scattered on the surface; while in the
more elevated parts of the country, its invariable position is such as
above described. The character of the ore in many localities is such
as to promise great facility in reducing it to the metallic state, toge-
ther with a large per centage of resulting metal. A specimen ob-
tained from above the marl on the cliff at Mount Pleasant, Surry
county, yielded by analysis in the 100 grs,

per oxide of iron, 72.40
alumina, 3.90
silica, Grol
water, 14.35
98.36

Loss, 1.64
100.00

With a sufficient supply of ore like this, accompanied with the ad- -
vantage of a shell limestone sometimes beautifully crystalline, in its
immediate vicinity, the manufacture of iron would promise a high
degree of productiveness; and it is by no means improbable that in
some parts of this region the supply of the ore may be found suffi-
cient to make such an enterprise not only safe but profitable. The
subject is at all events worthy of some attention. Indeed it appears
not a little surprising that this rich mineral seems hitherto to have
escaped observation, or at least to have been regarded as undesery-
ing of an especial notice.

In some places, as for example, in Essex county, chiefly upon the
ridge land, beds of a ferruginous sandstone are found of sufficient
extent to be used as a building material. This rock is not to be
confounded with the sandstones which occur some distance to the
west of this, on the borders of the primary region, but it is to be

15

looked upon as in the case of a very similar material recently made
the subject of minute inquiry by my brother in New Jersey, as a
remnant or outlying portion of a once somewhat extensive deposite
of ferruginous gravel and conglomerate, which by subsequent de-
nuding action has been almost entirely removed.

The matter which in most cases rests immediately upon the
shells, is a yellowish brown sand, frequently ‘containing a large
proportion of clay. Throughout this mass, and often extending to
the distance of five or six feet from the shells, particles of green
sand, or the silicate of iron and potash, are more or less abundantly
disseminated ; and in the immediate vicinity of the shells, these par-
ticles are generally condensed into narrow stripes conforming in
flexure to the irregularities of the bed beneath. Even where a
deep hole exists in the layer of shells, the stripes of green sand are
seen still following the depression and rise of the surface, and pre-
serving a uniform distance from it. Sometimes these thin layers
are so much indurated as to have almost the appearance of stone.
In none of the strata above described have fossils of any description
ever been discovered.

The materials with which the shells are intermixed, or in which
they are embedded, have various characters. In some cases they
consist principally of a nearly white sand ; in others the argillaceous
matter greatly predominates, and the mass is a somewhat tenacious
clay. Frequently much oxide of iron is mingled with the earthy
matter, giving it more or less of a yellow or brown appearance,
and this is the aspect which the upper beds containing shells most
usually present. Very generally the lowest visible fossiliferous
stratum is composed of a green silicious sand, and a bluish clay,
which being always very moist, is soft and tenacious, and presents
a dark blue or black colour. At the base of the cliffs on the
James and York rivers, this stratum may be traced continuously
for considerable distances, rarely rising more than two or three feet
above the level of the water, and presenting an even horizontal
outline. In the deep ravines, and low down in the banks of shells,
generally, throughout this region, a similar dark bluish green argil-
laceous sand is observed, enclosing frequently a great number and
variety of shells. This constitutes what is usually denominated
blue marl, which from the soft condition of the shelly matter which
it contains, as well as the predominance of clay in its composition,
is found peculiarly beneficial when applied to the more arenaceous

16

varieties of the soil. Many highly valuable marls extensively in use
are of this description.

The very general existence of the lower stratum, above described,
forms an interesting and prominent feature in the geology of the
Miocene Tertiary districts, as well of eastern Virginia as of
Maryland. Throughout all the upper fossiliferous strata, as well
as in the argillaceous beds just mentioned, will be found disseminated,
greenish black grains of Silicate of iron and potash, identical with
those already described as existing in the stratum immediately
overlying the shells, and having the same form and composition
with the granules contained very abundantly in an older formation,
both in this country and in Europe. In some beds of the marl or
shells, these particles so abound as to give a very deciced colour to
the whole mass. In specimens from James City and York counties,
as much as thirty-five per cent. of the green sand has been found,
and occasionally shells are seen filled with this substance almost
alone.

The surface of the strata containing shells is usually irregular.
Sometimes it rises abruptly, in the form of a hillock,, then it is
scooped out into depressions of a few feet in depth. These irre-
gularities, however, are apparently of two kinds; the one the origi-
nal form of the deposite, the other produced by denuding action upon
the surface. Thus in many places the same stratum may be re-
marked, rising with more or less abruptness, then again descend-
ing, and perhaps preserving a nearly horizontal line for some dis-
tance, marked at its upper surface by a clear and unbroken outline,
and presenting no indication of violent abrasion from above. In
other places, and this is a very frequent occurrence, deep and irre-
gular furrows and cavities are seen, such as would naturally arise
from the action of the currents and eddies of a large mass of water
in rapid movement. Whether from this cause, or from the gradual
dissolving action of percolating water, sinks exist in this region in
many places, though they are by no means as numerous or ex-
tensive as in the limestone districts.

Having thus given an account of the nature and arrangement of
the strata overlying the shells, as well as those in which they are
embedded, we will now describe the general condition and disposi-
tion in which the shells occur.

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Ssh

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MN SRR OD.

17
CONDITION OF THE SHELLS IN THE TERTIARY DEPOSITES.

In general the state of the shells, and their arrangement in the
earth, are such as to indicate their tranquil deposition at the spots in
which they are found. Thus the corresponding valves are very
often found together and closely shut. Many of the smaller shells,
such as Arca centenaria, Arca incile, Nucule, Venericardia alticosta,
and Chama congregata, which are most usually found thus, are
_ often either entirely empty, or contain a small quantity of clay
that is quite impalpable,Wndicating plainly that they have been ex-
posed to no violence, and that only such solid matter as could pass
between the edges of the closed valves had obtained access to the
interior. Whenever such shells, however, have been previously
drilled, as is very frequently the case, even with the largest and
thickest shells, the interior is found entirely filled with sand, clay,
green sand, and small fragments of shell. In most cases the larger
species of shells, even when their valves appear to be in accurate
juxtaposition, is thus filled, and in this case it cannot be supposed
that the contained matter has entered through the holes thus drilled,
since in many instances shélls of considerable magnitude are found
imprisoned within. Such shells, no doubt, after the death of the
animal, remained open, or at least partially so, and received the
sand, clay and other materials which they contain, by the gentle
action of the waves. The ligament at the hinge in the mean time
would decay, until at length, yielding to the pressure of the accumu-
lating matter above,the shell, in favourable circumstances, would
collapse into its natural closed condition.

The very common occurrence of the valves in juxtaposition, is
a striking proof, that during or subsequent to their deposition,
they have not been exposed to violent agencies. This becomes
even more remarkable in the case of such shells as the Panopea
reflexa, which almost in every instance is found with the valves
properly united. The connexion between the two valves in this
shell is the slightest imaginable, after the destruction of the natural
organic bond, and an inconsiderable force would have sufficed to
separate and break the valves.

The admirable preservation of the shells in many cases is also
an interesting fact, and affords another evidence of the absence of
all violent agencies at this period. The most fragile species of
Natica, delicate Tellin, Mactra Tellinoides, the shell and processes

3

18

of the Crepidula, the minute and sharp angles of the Fusus Tetricus,
the thin and hollow Fissurella—are found in perfect preservation
in many places. The state of the shells seems to depend chiefly
upon the mechanical texture and chemical character of the materials
with which they are mixed, and of which the overlying stratum is
composed. In the moist blue clay, the shells are generally found in
a very soft condition. In a highly ferruginous clayey bed they are
found either partially or entirely dissolved, and beautiful casts re-
main in their stead.

In many places entire banks occur, composed of casts of Chama
and other shells, sometimes separate, sometimes cemented together

so as to form a species of rock. These appearances occur chiefly

near the surface, and when the soil is porous and ferruginous.
The casts thus formed, often consist chiefly of carbonate of lime,
and in many specimens as much as eighty per cent. of this sub-
stance is found. Casts of this kind belong mostly to the smaller
shells, and by far the most common are of the Chama congregata.
These, as already stated, are often found nearly or quite empty,
and we may, therefore, conceive, that as the matter of the shell in
an extensive bank of Chamas is gradually dissolved, the water
charged with carbonate of lime enters the cavities, and slowly de-
posites the carbonate mixed with fine particles of clay and sand.
Thus by degrees the cavities are filled. In the mean time the shell
disappears, frequently leaving on the surface of the cast a chalky
covering, like the decomposed inner film of shelly matter. In sup-
port of this explanation it may be added, that in many casts beauti-
ful crystals of carbonate of lime are found, forming a portion of the
cast, and having the appearance of Dog-tooth Spar. In some cases
the shelly matter appears to have been dissolved, and its place sup-
plied by the crystallized carbonate, encrusting the earth formerly
contained within the shell. Sometimes, too, a thin film of oxide of
iron surrounds the cast, showing very distinctly all the markings
of the inner surface of the shell. In many localities, presenting a
series of beds differing in composition, the shells will be found per-
fect in some of them, while in others immediately above or below,
only casts remain. Thus at the College mill, about one mile from
Williamsburg, the upper fossiliferous layer is a yellow silicious sand,
containing perfect shells. Below this is a brown ferruginous clay,
filled with the most beautiful casts of Chama, Pectunculus, Turri-
tella, &c. The shelly matter has entirely disappeared, and the

Re ee

Ty Stee Re

eeseteieatet a cheats

ene

TTP TEs

TE I

19

easts lie loosely in the cavities produced by the removal of the
shells, entirely distinct from each other, and covered by a film of
oxide of iron. The layer beneath, consisting of bluish green
silicious clay, is full of well preserved Pectens, Pernas, and a variety
of other shells.

In general, the various species of shells are found associated in
colonies or groups, but, as in the case of banks of recent shells,
these colonies contain many scattered specimens, differing from the
general contents of the group. The two species of Chama, the C.
congregata and C. corticosa, which are found in almost every de-
posite of shells in this region, in many cases form extensive beds,
with a very small admixture of other genera. The best agricultural
marl, of a purely calcareous nature, which is used in lower Virginia,
is derived from these beds of Chama, the friable texture of the shell
upon exposure to the air, rendering this species of marl more easy
of application to land, and more prompt in its ameliorating effects.
Crassatelle often form an extensive deposite, and the large Pectens
occur in continuous layers of considerable depth and extent. The
different species of Arca, Artemis Crepidula, &c. present a similar
arrangement. Even those shells which are of comparatively rare
occurrence, are usually found in little groups. Thus the Isocardia
fraterna is found, to the extent of a dozen or twenty, closely packed
together. This gregarious assemblage of shells of the same species
is what would naturally be anticipated in the absence of violent
agencies during or after their deposition, and furnishes another very
striking proof of the comparatively tranquil condition of the sea or
estuary in which they were allowed to accumulate.

DISPOSITION OF THE FOSSILS.

In nearly all the vertical sections of the deposite we are now de-
scribing, a series of beds or strata may be observed, each dis-
tinguished by the predominance of one or more species, and the
order of superposition of these beds frequently continues without
interruption for some distance. It does not appear, however, that
in localities remote from each other, the arrangement of the
shells is always alike, although in many instances there appears to
be a striking correspondence. In a majority of cases in the neigh-
bourhood of Williamsburg, the upper layer is composed principally
of Chama congregata. In many localities also, the large Pectens

20

mingled with Ostrea Virginica occupy the highest place. But gene-
rally, the same shell re-appears as a predominant constituent of one
or more of the subjacent beds; and such is the diversity of ar-
rangement, even in places but a few miles distant, that it is obvious
that no general order of succession exists. Thus, in a range of
three miles we find Perna maxillata in some localities in the lowest
stratum of dark blue argillaceous sand; in others, forming an
upper, or even the highest layer of the series. At Waller’s mill,
three miles from Williamsburg, this fossil overlies the other shells;
whereas at the College mill, as already stated, it forms a part of
the lowest visible stratum.

With the view of conveying more precise ideas of the disposition
of the fossils in this region, we annex the following details in relation
to some of the more important localities, which have been minutely
examined.

King’s mill, one of the most interesting fossil localities in the
neighbourhood of Williamsburg, is situated on the north bank of
James river, about twenty-five miles from its mouth. The cliff in
which the shells appear is abrupt, and has a height varying from
twenty to forty-five feet above the water. The strata of shells
extend along the river with slight interruptions, when the cliff sinks
nearly to the level of the water, for a distance of between two and
three miles, and they are found in a somewhat similar order of
superposition for some distance inland. Their general direction is
horizontal, but the outline of any one stratum is frequently very
irregular, the surface rising and falling with a steep inclination.
This irregular outline is particularly remarkable with the beds of
Chama, which are very thick at some points, and then fine out
rapidly and again expand.

This deposite of shells is covered to the depth of from four to six
feet by a brownish yellow sand, intermixed with stripes of clay.
Beneath this is a thin layer of about one foot, of very argillaceous
and ferruginous clay of a red colour. This rests upon a few inches
thickness of gravel, consisting of water-worn quartz, rarely larger
than a pea. Beneath this is a layer, from one to two feet thick,

consisting of yellow sand, containing a great deal of the green or
chloritic sand, arranged in narrow stripes. Next follows a layer of
the same sand, containing principally Chama and Venus deformis.
This is from two to three feet in thickness. Immediately below is a
stratum consisting almost exclusively of Chama, with a few Area

ee

EEE SS SS ST OG

21

centenaria, &c. This stratum, varying from three to four feet in
thickness, is a mass of compacted shells, with but little earthy
matter intervening. The earthy matter contains a very large pro-
portion of the chloritic sand. The next stratum is composed chiefly
of large Pectens, and has a thickness of from one to two feet. Be-
low this is another dense stratum of Chama, together with Arca
centenaria, Panopea reflexa, &c., and also very rich in the green
sand. Thickness, from four to six feet. Then follows a second
layer containing Pectens with Ostrea compressirostra, one foot in
thickness. A third stratum in which Chama predominates, follows
next, in thickness from two to three feet, and at the base of the
cliff is a layer containing Pectens, Ostrea compressirostra, &c. from
four to five feet in thickness.

Thus through a height of more than twenty feet in some places,
the cliff consists principally of shells, of which there are a great
many species, besides those mentioned as predominating in the
several beds. On the extensive contiguous estates of King’s mill
and Littletown, these shells are largely used as a manure: and for
this purpose the first and second beds of Chama are preferred on
account of the immense amount of calcareous matter, and the large
proportion of green sand which they contain. Judging from the
occasional appearance of bluish green clay on the line of the beach,
and in some places immediately at the base of the cliff just de-
scribed, it is highly probable that a continuous stratum of this sub-
stance lies beneath the other beds throughout the whole extent
observed. A horizontal bed of yellowish clay extends for some
distance along a lower portion of the cliff, in which there are no
fossils ; running within a few feet of its upper edge, and beneath
this bed, and parallel to it, is a thin layer of the iron ore formerly
described. At the foot of this cliff appears the underlying stratum
of clay.

DESCRIPTION OF THE CLIFFS AT YORKTOWN ON YORK RIVER.

The elevation, abrupt form, and peculiar construction of the cliffs
at this point, and for some distance, both above and below, render
it an interesting spot to the geologist. A dry and ample beach, un-
interrupted by creeks or inlets for several miles, affords a ready
access to the banks, while the river’s edge, strewed with fossils
which have fallen from the cliff, exposes a considerable variety of

22

interesting specimens. Immediately at York, the river is only three-
eighths of a mile in width, but both above and below it expands to
a breadth six or seven times as great.

At Wormley’s creek, about two miles below the town, the cliff
about to be described begins; but from this point, down to the ex-
tremity of the peninsula, the banks are uniformly flat and low. The
cliff here consists at bottom of a bluish sandy clay, containing im-
mense numbers of Turritella alticosta, Cytherea sayana, and many
small Univalves, over which lies a layer of brownish yellow sand,
with very few shells, and those chiefly Nucula limatula, and a few
other species. To this succeeds a stratum composed almost entirely
of Crepidula costata, so closely packed together, as to leave little
space for sand or other earthy matter. The whole is covered to a
variable depth by a stratum of coarse sand of various strong tints,
and evidently highly ferruginous. The elevation of the cliff in-
creases, and the nature of its contents gradually changes in ap-
proaching York. The lower stratum disappears entirely after con-
tinuing for something less than half a mile, previous to which, how-
ever, its fossil contents are changed; the layer of the Turritelle
being replaced by Crepidula closely packed together. Crepidula
still runs on horizontally above, and the intermediate stratum is now
densely filled with Pectens, Venus deformis, Ostrea, and a great
variety of small shells frequently connected together, so as to form
hard masses of considerable size. Still higher up the river the de-
* posite assumes the character of successive layers composed of com-
minuted shells, connected together so as to form a porous rock.
These fragments are generally so small and so much rubbed and
water-worn, as to render it impossible to ascertain the species of
shells of which they once were portions. Many small shells, and
occasionally large ones, particularly Pectens, are found mingled with
the other constituents of the rocks ; and in some places thin layers
of shells, such as Venus and Crepidula, intervene between the ad-
jacent strata. The height of this fragmentary rock amounts in
some places to forty feet. In most places it has a highly ferruginous
aspect, though this is not invariably the case. Frequently shells of
considerable size, such as Lucina anodonta, are seen coated with,
or entirely changed into, crystalline carbonate of lime, firmly ce-
mented in the mass. The texture of the rock is various, at some
points admitting of being readily excavated by the pick and spade,
so as to form caves which have been occasionally used by the in-

PLE ARES ENE SS BOL NT TIO OE a

23

habitants; in other places exhibiting a hard and semi-crystalline
structure, and having the compactness of some forms of secondary
limestone. The lower portion of the cliff, having less cohesion than
the rest, has been scooped out by the action of water, so as to give
it occasionally an impending attitude.

Above the town, the stratum of fragmentary rock becomes much
thinner, being now reduced to about ten or twelve feet. A stratum
of yellowish argillaceous clay, abounding in Artemis acetabulum,
Mactras, and other large shells, lies immediately beneath the rock ;
and lower still, appears the stratum of bluish clay, filled with
Nucula Limatula, several species of Fusus, and various other
fossils.

A narrow layer of iron ore extends along the cliff, with occasional
interruptions, at a small distance above the fossiliferous strata.

This fragmentary rock continues in a narrow band, with some
interruptions, for about a mile and a half above York. Beyond
this point it is met with chiefly in detached masses. Extensive
beds of shells, similar to those which appear at York, come to view
in the vicinity of Bellefield, and line the shore for a distance of about
three miles. These beds rest on the usual stratum of sandy clay,
and are in some places, as already described, covered by a stratum
of the same substance. At a stil] remoter point, about six miles above
York, on Jones’ plantation, a porous rocky mass occurs, overlying
the stratum of shells in a thin and interrupted layer. Though very
similar in appearance to the fragmentary mass before described,
and evidently at one time composed of portions of shells, it is almost
devoid of any trace of carbonate of lime. It appears to consist of
silex, slightly tinged with oxide of iron; approaching in its porous
character and harsh gritty texture, to the nature of the burr stone
of France. Associated with this, is a more compact rock, contain-
ing some carbonate of lime, with much silex, and exhibiting very
perfect casts and impressions of Pectens, Cardium, &c. Over these
strata is the usual layer of ironstone, and the general aspect of the
upper beds is somewhat ferruginous.

It is interesting to remark, that with some interruptions, a frag-
mentary deposite, similar to that observed at York, extends to the
lower extremity of the peninsula. At Pocosin, a flat swampy
country, which is often inundated by the tides, this deposite is uni-
formly met with by digging a few feet below the surface. Pectun-
culus, Pecten, Ostrea, as well as numerous small shells, occur

24
mingled with it, as at York; the fragments, however, are not ce-
mented together but form a loose friable mass. A rock, consisting
of cemented fragments of shells, occurs also at various other points
on the eastern portion of the Miocene district ; and a fragmentary
deposite, like that above described, is found near the extremity of
all the peninsulas formed by our great rivers.

A very interesting feature in the structure of the cliff at York
remains to be described. Though the general direction of the fossil
beds is nearly horizontal, several of the strata of rock are composed
of transverse layers parallel to each other, generally dipping to-
wards the north, and making an angle of fifteen or twenty degrees
with the horizon. The course of these lamine sometimes differs in
adjoining strata, and in some places the obliquity diminishes gradually
until the laminz become horizontal; thus presenting a remarkable
resemblance to the appearances described by Lyell and others, as
existing in the Crag of England. The phenomenon here described,
viewed in connexion with the fragmentary structure of the rock, and
the general distribution of broken shells over the lower extremity
of the peninsula, would seem to indicate the former agency in this
district of coast currents and an ocean surf. The beds of shelly
matter comminuted by these means, and subsequently elevated
above the level of the tide, would be gradually cemented into a
rocky mass by the crystallization between the particles of such
portions of the calcareous matter, as the rain when just fallen was
capable of dissolving. 'The solvent power of rain, being chiefly due
to a portion of carbonic acid with which it becomes united in its
descent through the air, would be lost, as the liquid percolated
through the shelly strata, and thus the calcareous matter which it
had seized, would be gradually deposited in the crystalline form.

Besides shells and Zoophytes, the bones of cetaceous animals
and the teeth of sharks, are of very frequent occurrence in the
fossiliferous beds, but no remains of fresh water or land animals
have as yet been discovered. The total number of species of shells
from these points which have yet been identified, is about ninety-sjx,
to which may now be added several new species recently dis-
covered,"and described in a joint paper by Professor H. D. Rogers
and myself.

The structure of the interesting portion of the state lying on the
eastern side of the Chesapeake is, so far as hitherto explored, ex-
tremely simple; but as yet only the surface strata have been

PY SALT SES ST ae

Aw ee as ea a we Ue

25

examined, and it is far from being improbable, that at no very con-
siderable depth beyond that reached by the ordinary wells of the
country, deposites calculated to prove of much economical value,
might be attained. Beneath the superficial sands and sandy clays
of the country, a bed of clay of a tenacious character is first reached,
frequently impregnated with salt, and communicating to the water
obtained from it more or less of a brackish flavour. Beneath this
a more arenaceous bed occurs, beyond which, as far as I can learn,
no digging has been carried. From this more sandy stratum, water
of a purer quality is procured. Hitherto no beds of marl or fossil
shells have been found anywhere in this region. Yet there is
reason for the opinion, that such deposites would be met with by
boring to some depth, and possibly near enough to the surface to
prove available in the agriculture of the country.

The water of the Miocene mar] district, whether of wells or
springs, presents nearly as great variety as the mineral beds from
which it issues. In the more eastern parts of the region, it generally
contains a notable impregnation of common salt, and in neighbour-
hoods where shell marl abounds, a marked proportion of calcareous
matter. The copiousness and transparency of springs of the latter
description, as well as the carbonate of lime which they hold dis-
solved, give them a character nearly allied to that of the limestone
springs of other regions, while the common salt which they almost
invariably contain, and with which they are sometimes strongly im-
bued, constitutes an important feature of distinction. The beds of
ferruginous clay and sand in many cases, impress a slight chaly-
beate character upon the water, and accasionally impart to it so
large an impregnation of iron as to render it of decidedly medicinal
utility.

Owing to the calcareous matter, and occasionally other substances
which it holds in solution, nearly all the water of this region pos-
sesses the character of hardness. By boiling, this evil is entirely re-
medied ;—the carbonate of lime is precipitated, first rendering the
liquid cloudy, and subsequently collecting on the sides and bottom
of the vessel in the form of a thin incrustation. In such of the arts
as require a water free from this peculiarity, the marl water should
be boiled previous to use; or, in lieu of this, though by no means an
effectual substitute, it should be exposed for some time to the sun in
open reservoirs. The carb. acid which is the chief solvent of the cal-
careous matter, being expelled by heat, suffers the latter to separate

4

26

from the liquid, and thus the cause of the hardness of the water is in
a great degree removed. It is obvious from these facts, that the wa-
ter obtained from strata of gravel, sand or pure clay, will in general
be purest and most suitable for employment in the arts. As an ex-
ample of the kind of impregnation usual in the water of this district,
I subjoin the results of an analysis of the contents of a spring in
James City county, near Williamsburg. In 400 cubic inches of this
water, the aggregate of solid matter was found to be 104.49 grs.
consisting of the following substances, viz:

Muriate of soda, 49.84
Muriate of lime, 15.08
Carbonate of lime, 26.73
Sulphate of lime, 6.24
Silica and alumina, 4.00
Sulphate of soda, 0.25
Ammonia, a trace.
Organic matter, 1.00
Loss, 7D

104.49

The large proportion of Muri. soda shown to be present in the
above instance, is an interesting fact, particularly when taken in
connexion with the locality whence the water was procured. For,
it cannot be considered probable that this ingredient could be de-
rived from the neighbouring rivers or the bay, as this would imply
an extent of filtration in a horizontal and upward direction, which
it would be unphilosophical to admit. It is rather, as I conceive, to
be looked upon as referable to the former impregnation of saline
matter derived from the waters of the ocean, beneath which nearly
all the strata of this region were originally deposited.

NATURE AND VARIETIES OF THB MIOCENE SHELL MARL.

In the general description of the district of which we are now
treating, a detailed account has been given of the arrangement of
the beds of fossils as they occur in nearly all the localities which
have been examined, accompanied by an enumeration of the princi-
pal shells, an account of the materials in which they are embedded,
and with which they are associated in contiguous strata. We are
next to consider the materials of these beds in relation to their agri-
cultural importance, and to exhibit the relative value of the marl of

RNR

Sapeeeaersit-s 6,

REO NT TIES ag I a RS RE AN ae es sd cae sat a ee

&
&
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2 EOE TELIGEO ILE LI LOGE ISLE LGD TE

zed

27

different localities as illustrated by chemical examination. A large
proportion of the matter of all shells consists of carbonate of lime.
Hence they are nearly identical in composition with limestone, chalk
and marble. To this ingredient, in whatever form it may be applied
to the soil, general experience has ascribed a very high degree of fer-
tilizing power, and hence, in the application of all the varieties of cal-
careous marl, we are guided chiefly by the proportion of the carbo-
nate which they contain, as determined by chemical analysis. It
should not, however, be inferred, that the various mixtures of earths
and other substances with which the calcareous matter is usually as-
sociated, are devoid of useful action when applied to land. The ex-
perience of agriculturists is certainly inconsistent with such an opi-
nion, though it has most clearly evinced the powerful efficacy of cal-
careous manures. The invaluable publications of the editor of the
Farmer’s Register by directing the attention of farmers to the em-
ployment of the shell marl with which nature has supplied them in
such rich abundance, have led so extensively to the application of
this manure, and have produced so general a conviction of its fer-
tilizing effects as to render it unnecessary in this place to introduce
either facts or arguments in its favour. To the valuable practical
suggestions of this gentleman, contained in the ‘‘ calcareous manures”
and other publications, we are indebted for much of the amelioration
which has taken place in the agriculture of eastern Virginia, and I
therefore cannot do better, in alluding to this branch of my subject,
than to recommend these works to the earnest perusal of all who are
interested in advancing the prosperity of that portion of the state.
But although the richness of the marl is mainly dependent on the

proportion of its calcareous contents, it is also largely influenced by

the nature and condition of the shells of which it is composed. _ It is

well known that the recent oyster shell, especially in its unbroken

state, is far less immediate and powerful in its action upon land than

the friable and pulverulent shells, of which many of the most valua-

ble marl beds are principally made up. Yet in the composition of
the recent oyster shell, the amount of calcareous ingredient is nearly

as great as in the richest marl beds which we have examined. Ac-

cording to an analysis which I made some years ago, 100 grains of
this material were found to contain :

28

Carbonate of lime, 95.18 gts.
Phosphate of lime, 1.88
Silex (probably accidental,) 0.40
Water, 1.62
Insoluble animal matter, 0.45
Loss, &e. 0,45
100.00

[Vide Farmer’s Register, Vol. 1, and Silliman’s Journal.

These remarks being also applicable to some species of fossil
shells, it becomes necessary to a judicious selection of the marl, to
give some attention to the different nature of the shells contained in
the several varieties of marls offered to our choice.

KINDS OF SHELLS WHICH ARE LEAST LIKELY TO BE USEFUL.

The Fossil oyster and Scallop shells, (Ostrea Virginica and Pec-
ten,) of which many marl beds are almost exclusively composed, are
generally found in a nearly unaltered state. Comparing the compo-
sition of these shells, as ascertained by my analysis, with that of the
recent shells, the animal matter which, though small in quantity,
seems to act powerfully as a cement for the other materials, was
found to have been retained in almost undiminished proportion; and
thus these shells are scarcely better fitted for the soil, than recent
ones of the same species. It is to the animal matter retained by the
fossil scallops that we are to ascribe the dark colour which they as-
sume when burnt for lime. Whatever might be the usefulness of
this ingredient if mingled with the soil, it here operates to impair the
value of the shell as calcareous manure by the insoluble character it
imparts to the materials it holds together. Next in tardiness of dis-
integration, and in consequent inefficacy as a manure, may be enu-
merated the large clam, (Venus mercenaria,) and an oblong smooth
flat shell, (Crassatella.) These, however, have evidently undergone
a change, which prepares them for yielding, more readily than the
former, to the agencies of the seasons. Most of the other species,
though entire when first found, soon fall to pieces and spread their
fertilizing fragments through the soil. There is, however, even
among them some room for choice—and this leads us to consider
the

29
KINDS OF SHELLS WHICH ARE MOST SUITED FOR THE PURPOSE OF MARLING.

The Chama, formerly mentioned as occurring in extensive beds
in some portions of the Miocene, and existing in considerable pro-
portion in nearly all the fossil strata, forms the principal component
of some of the most productive marls. This is a small two-valved
shell of rugged exterior, which readily breaks to pieces in the ground,
and is spread evenly over the land with great facility. Another
shell, (Serpula,) of which there are numerous rich beds in Surry
county, possesses these advantages in a still higher degree. From
its fragile texture, and irregular tubular structure, it is quickly min-
gled with the soil ina minutely subdivided state, and as like the
Chama, it frequently occupies the marl beds to the exclusion of other
fossils, it furnishes a marl of a very superior description. As a ge-
neral rule, the small shells are most likely to prove efficacious, as well
from the fact that, where they occur, the proportion of carbonate of
lime and green sand is usually great, as because they are most
easily reduced to the condition in which they become available in the
land.

Of the Pulverulent white marl.—In many situations the marl pre-
sents an appearance not very unlike that of an impure chalk. The
mass of the stratum is chiefly made up of a white or yellowish fri-
able material, intermixed with fragments of the harder species of
shells. In such cases the shells are rarely found entire, and the con-
dition of the fragments is usually such as to render it difficult to re-
cognise the species of fossil to which they belonged. Many exten-
sive beds of mar] of this description have been opened in the coun-
ties of Middlesex, New Kent, James City, York and Gloucester, all
of them largely abounding in calcareous matter. Even as much as
97 per cent. of this substance was found in a specimen from one of
these localities ; and it will appear from the table of calcareous marls
hereafter to be given, that in general the proportion exceeds 80 in
the 100. Occasionally, however, a mixture occurs in which the cal-
careous matter is blended with a large proportion of white clay and
sand, presenting in the mass an aspect so nearly resembling the for-
mer, that without chemical analysis it would be difficult to distin-
guish between them.

Of the Blue marl.—In our general description of the arrangement
of the fossiliferous strata, mention has been made of the bluish green
or clayey marl which occurs Jow down in the ravines and near the
water’s edge on the river banks. This is what is usually known

30

amongst farmers as the blue marl. From the soft condition of the
shelly matter which it contains, and the predominance of clay in its
composition, this has been found peculiarly serviceable when applied
to the more arenaceous varieties of soil. In the quantity of calcare-
ous matter which it contains, it is usually inferior to the beds of a
white or brown colour, which in many places rest above it, though
itis not to be inferred that in many instances it may not prove
equally advantageous to the land. The colouring matter of the clay
appears in part to consist of a carbonaceous matter, derived proba-
bly from the organic materials originally associated with the shells,
and often in part of a minutely divided greensand, either of which
ingredients might be expected to aid the calcareous and clayey mat-
ter in benefiting the soil.

Of the hard Ferruginous Marl.—In some localities the beds con-
sist of shells more or less broken, intermixed with a brown ferrugi-
nous sandy clay, and often cemented with these materials into
masses which are broken with some difficulty. These, although
rich in calcareous matter, must obviously, from their mechanical tex-
ture, prove less valuable than either of the former. To this class,
also, may be referred the shell rock, and fragmentary masses ap-
proaching to limestone, which occur in various places.

From the large per centage of carbonate of lime, which these con-
tain, there can be no doubt that, by burning, they might be con-
verted into a highly valuable lime. A specimen from the cliff at
York, yielded eighty-seven per cent. of calcareous carbonate, as
large a proportion as most of the valley limestone have been found
to contain: computing the quantity of caustic lime, corresponding to
this, we find that one hundred pounds of the shell rock would yield
48.7 pounds of strong lime. It is, therefore, well worthy of consider-
ation, whether the conversion of this material into lime, might not
be an object of profitable enterprise. In the neighbourhood of York
and other places, where it occurs, rock of sufficient hardness might
be obtained in great abundance and at comparatively little cost ; and
the cheapness of fuel would render the operation of burning, one of
moderate expense. That much of this rock,’ when exposed to
intense heat, would fall to pieces, and thus injure the value of the
product for distant use, is undoubtedly true. But there is also
much of it found in bands throughout the cliff, which has almost as
great solidity and permanency in the fire, as a secondary limestone,
and from this, a lime of superior character might unquestionably be

CRN ERITRI Tae:

seen

aaa ics

|

31

produced. Owing to the great abundance of shell marl in these
places, and the general resemblance of this material to the consti-
tuents of a marl bank, its probable utility in this point.of view, ap-
pears hitherto to have been overlooked. But regarding it in its true
light, as a tertiary limestone, we see no reason why it should not
become a source of profitable manufacture in its immediate vicinity.

OF THE GREENSAND, SULPHATE OF IRON, SULPHUR, AND OTHER MATTERS
ASSOCIATED WITH THE MARL BEDS.

Greensand.—As already intimated, this substance is frequently
found disseminated in the marl, and also in the overlying stratum of
clay or sand. From the remarkable effects of comparatively small
quantities of this material when applied to land, there can be no doubt
that many of the marls of lower Virginia owe some of their value
to its presence. Supposing only as much as ten per cent. of this
substance in a marl, and this is far below the amount which I have
ascertained to exist in many localities, one hundred loads of marl
would correspond to ten of the greensand, an amount which in New
Jersey has often been found productive of striking benefit. Several
of the most efficient marls which I have examined, were more
remarkable for the large proportion of this substance contained in
them than for their richness in calcareous matter. In many marl
pits which I have visited, the impressions of the pick and spade were
streaked with green marks, which upon inspection were found to
result from the bruised granules of this matter. In such cases, there
can be no doubt of the existence in the marl of an amount of green-
sand capable of affording material aid to the growing vegetable. In
the layer immediately above the marl, also, it sometimes exists in
considerable quantity—and hence instead of rejecting this overlying
mass, in many cases it would be decidedly better to carry it out
upon the land along with the calcareous matter. The experience of
many farmers has already shown the propriety of this plan, and
some even entertain the opinion that this upper layer, where the
greensand abounds, is quite as beneficial as the marl itself. Fur-
ther observations respecting the greensand will be given in treating
of the Eocene marls, of which it constitutes a very important ingre-
dient.

Sulphate of Iron and Sulphur.—tIn some parts of the Miocene
district, there occur beds of clay more or less sandy, and usually of
a dark colour, containing these substances in a minute but still ap-

32

preciable quantity. Such matter, there is reason to believe, would
not in general prove directly beneficial to the soil. The former has
been thought positively detrimental to vegetation, and certainly
when applied in considerable quantity, this is its effect. What
agency it might exert in a more diluted state, and mingled with
other matter, we are without the means of determining. Probably
under such circumstances it might operate as a stimulant, and thus
contribute to the growth. The same doubts are also applicable to
the other substance above named. Yet in some well authenticated
cases, the action of these copperas and sulphur clays has been found
strikingly beneficial. In these instances, however, it would seem
that much if not all the benefit was produced by the effectual protec-
tion which even minute quantities of these substances, especially the
latter, afford against the attacks of insects. In a cotton field in
which all the alternate rows were lightly sprinkled with earth of this
description, the plants so treated grew up vigorous and healthy,
while the others became sickly and were nearly devoured by insects.
Much careful observation is required to determine the kind and
mode of influence which these substances exert, and it would be
premature, in our present ignorance of the matter, to assert any con-
victions on the subject. The presence of the former of these ingre-
dients, if not recognised by the copperas flavour, will be readily dis-
covered by steeping the earth in water, decanting the clear liquid,
boiling it down to a small volume, and then adding tincture of galls
or prussiate of potash. A black or brown colour with the former,
or a blue one with the latter, would indicate its presence. The ex-
periment, however, should be made in a glass or china vessel. The
sulphur becomes manifest to the smell when the clay is heated, and
even at ordinary temperatures its peculiar odour may often be per-
ceived.

The following table exhibits the per centage of carbonate of lime
in a number of the Miocene marls which I have examined. The
analysis were made with the “apparatus for analysing calcareous
marls and other carbonates,” described in The Farmer’s Register
and Journal of Science. No attempt was made to ascertain the pro-
portions of sand, clay or greensand, because the trouble of the ana-
lysis would have been increased more than ten fold, and probably no
useful result could have been attained. In each experiment the ap-
pearance and character of the undissolved matter was noted, and
thus a general estimate formed of the other ingredients of the speci-

33

men.

These notes are contained in the fourth column, the first

giving the localities, the second the aspect, and the third the quan-

tity of calcareous matter.

TABLE, exhibiting the per cent. of Carbonate of Lime in

Miocene Marls.

GLOUCESTER.

Walter Jones,

ments of Perna,

Walter Jones, : White clayey marl,
T. W. Fauntleroy,

T. W. Fauntleroy—several feet
below surface, . ‘ :

Do.—from same bed near the] shells,

White pulverulent,

surface, : . . - |More arenaceous,
Dr. Taliaferro—from gray low

grounds, . =. : : : : °
Do.—black low grounds, . 5 . ae

Do.—highlands, upper stratum, =
Do.—highlands, lower level, .

ISLE OF WIGHT.
Burwell’s bay, . {Blue marl,
Ditto, F : . {Yellow marl,
Joel Holleman,
JAMES CITY.
The Grove—Burwell’s,

specks of g. sand,

Do.—from a lower stratum, . |Similar appearance—-specks

more numerous, .
King’s mill cliff, . z - |Similar aspect,
Judge Semple’s farm, two miles
below Williamsburg,
Dickie Galt’s, near Williams-
burg hospital, ‘
Dr. Semple, thirteen miles from
Williamsburg, ‘ Yellowish pulverulent,
Do. do.—another stratum, Grayish yellow,
Dr. Peachy’s, near Jamestown,|White pulverulent,

Similar aspect,

Pulverulent and white,

. |White sandy marl, with frag-

Fine chalky—few traces of

White, with small shells, .

Reddish gray, with fragments
of shells and numerous

37.1/The residuary matter chief-
ly silex—No greensand.

61.5/The residuary matter chiefly
clay, witha little g. sand.

60.0|Chiefly clay—No g. sand.

96.8) No g. sand.
61.8)\Sand.

62.0) A little g. s.—chiefly clay.

55.2/Sand, clay, and a conside-
rable proportion of Per-
oxide of iron.

80.2)A little g. sand.

60.2\Sand, clay, and large pro-
portion of g. sand.

54.7,Do. do.—still more g. sand.

iediee do.—much g. sand.

79.0;Do. do. do.
79,0) No g. sand,

\84.3 Sand and clay.

54.5 Do. do.—and some g. sand.
\7: .0\Chiefly clay.

72.7|\Clay, and a little g. sand.
69.1 Do. do.

Mr. Wynn’s, near York, ; Do. do.
Mr. Wade’s, § 3 ‘ Do. do.
: LANCASTER,
Curratomen—J. Cabell, Esq.—
Ist bed, . 4 : Grayish yellow—siliciousclay

filled with hollow casts of

Astarte Undulata, - |48.8/Clay, sand, and ox. iron—
Do. do.—2d bed, Fragments of shells, but no o g. sand,
casts, 3 . ; - 154.6 Do.
Do. do.—3d bed, * Do. rte Fea 57.4 Do.
Do. do.—4th bed, 3 Do. do. 52 7 Do.
Do. do.—dth bed, m ‘ Do. do. 38.4 Do.

34

ce

MIDDLESEX. -
Mr. Jesse’s, near Urbanna—
No. 1, + : . {White pulverulent, . . |92.3}Chiefly clay-
Do.—No. 2, . {Sandy and greenish blue, . {33.0/Much g. sand.
Dr. R. Christian, near Urbanna,|Chalky—small sisi of
shells, * . (59.5/Sand and clay.
Mrs. Thruston’s, 8 patles from
Urbanna, . ‘ . {White and pulverulent, . (95.4
NEW KENT.
Mr. B. Crump, five miles below
court-house, a . |White pulverulent, . - 193.6
Mr. Ro. Christian’s, ‘ Do. UO: a 70:1
Mr. J. Marshall, . ; 5 Do, don =. - 185.0
PRINCE GEORGE.
Mr.Wm. Harrison, . . Do. (1 (3 ote hoeseoe cal v pay
SURRY.
Mr. C. Jones, ea. GRR VIED Cow. a, WOO RAG i clay, and much g.
sand.
Mr. C. Jones—lower stratum, |Grayish yellow, . « {43.2)Sand, clay, ox. iron, and
much g. sand.
Do.—upper stratum, . . |Abounding in Chama, . '62.7/Do.—much g. sand.
Capt. Smith, court-house, . |Bank made up of Chama and
Serpula, . |72.91Much g. sand.
Bacon’s Castle, . . [White pulverulent, ‘ . 197.7{No g. sand.
Mr. D. Stith, court- house, . |White sand, with fragments
of Perna, ‘ j . {35 |Sand—no g. sand.
Union Hall, : x . |Very argillaceous, . . |29.8)No g. sand.
YORK.
Mr. R. Garrett's, three miles
below York, . |White pulverulent, . . 190.
Belle farm—Major T. Griffin, Reddish yellow—fragments 0
’ shells, - |79.2\Clay and ox. iron,
York cliff, ‘ 4 ; . |Rocky and subcrystalline, 87.31 Do. do.

EOCENE MARL DISTRICT.

As already indicated, the extent and boundaries of this interest-
ing portion of eastern Virginia are as yet in a great degree matters
of conjecture. The discovery of an Eocene deposite in the state first
announced by me about eighteen months ago, in a communication
to the Farmer’s Register, has been followed up by a minute per-
sonal examination of some parts of the district in which it occurs,
more especially on the James river and Pamunkey. Its existence
on the Rappahannock and Potomac has also been ascertained, and
specimens have been obtained from a number of intermediate points.
With regard to the region South of the James river, though facts
have been procured which show conclusively that the deposite con-
tinues to the southern boundaries of the state, time has not ad-
mitted of such an investigation as would be necessary in defining
its extent. A regularly continuing line of observations on the

35

Pamunkey river, commencing below the point at which the deposite
appears above the water’s edge, and extending up the river to the
junction of the North and South Anna, where it terminates, has
served to develope the arrangement and composition of the strata,
and to determine the width of this portion of the formation. An
inspection of the most important Eocene localities on the James
river has also contributed many interesting and valuable facts,
while on the Rappahannock and Potomac, its western limits have
been determined with as much accuracy as could be attained by
transient observations directed only to a few localities.

Wherever observed, the arrangement of the beds of the Eocene
and the minerals and fossils contained in them, have been found
strikingly alike, and hence the description of any transverse line of
the formation may be regarded as conveying a just representation
of its character throughout. At the same time, however, it is by
no means to be assumed, that in all localities the same arrange-
ment or composition of the strata must necessarily exist; for within
a short distance in observations already made, considerable diversi-
ties have been observed to exist. But there can be little doubt
that the general order of the strata already remarked, as well as the
character of the fossils which they contain, will present much uni-
formity whenever the formation may be discovered within the
limits of the state.

The existence of Miocene strata over the Eocene, has been re-
ferred to under a former head, and some account of this more
recent overlying deposite within the district of which we are now
treating, may, with propriety, be prefixed to the description of the
Kocene itself.

» OF THE MIOCENE WHICH OVERLIES THE EOCENE.

Westward of the limits of the Miocene previously defined, the
general level of the country continues gradually to rise. A surface
more generally undulating, and strewed with water-worn fragments
of stone, sometimes of considerable size, marks our approach to
the region of hills and rocks, whence these memorials of the de-
structive forces | of a former period have been derived. The
superficial strata i in the western portion of this district js generally
a coarse sand or gravel, often containing large masses of rounded
sandstone and other rocks, of which the parent strata are gene-

Yaw }

36

rally to be found at no remote distance to the northwest. An in-
spection of these pebbles is sufficient to show, that in many, if not
nearly all cases, they are derived from the grits and sandstones
with which the bituminous coal of eastern Virginia is associated,
while from the similar nature of the sand and gravel in which they
are embedded, we are entitled to conclude, that at least in part,
they also refer themselves to the same region for their origin. In
the hills at and below Richmond, and in many other places these
beds of gravel have considerable depth, and present a structure at
once curious and instructive. A series of strata at these places, in
some of which the pebbles are disposed in horizontal lines; in
others, in lines oblique, but still generally parallel, inclining down-
wards to various points in the different layers, give striking evidence
of the agency of those diluvial and oceanic currents, of which
geologists have discovered so many memorials in other regions, and
may serve when minutely studied, to throw much light on the
physical changes to which this portion of the continent must for-
merly have been subjected.

Beneath these beds of gravel, in many places strata of clay
occur; but whether referable to the same epoch of deposition, can-
not as yet be clearly ascertained. Many beds of very argillaceous
clay, suited for the potter and brickmaker, and occasional layers of
a pure beautiful yellow ochre, may be placed in this portion of the
series.

Other strata of clay and sand of a peculiar character present
themselves in many localities beneath the superficial beds. These
contain a record of their origin legible to the geologist, in the im-
pressions of shells and Zoophytes with which they are generally
filled. On comparing these casts, which in most cases can be
easily recognised even in their more delicate markings, with the
fossils of our Miocene marl strata, their identity is established, and
thus the strata in question at once take their places in the series of
Miocene Tertiary deposites. In many parts of Hanover, King
William, Henrico, and other counties in this range, these beds
of clay are found, usually characterised by a dark greenish gray or
brown colour, a sulphureous odour, and an astringent taste. On
Governor’s hill in Richmond, a stratum of the same kind is exposed;
and at this spot, the fossil impressions and other characters above
noticed, may be distinctly seen. Like the clays and sands for-
merly described as associated with the Miocene, these contain sul-

37

phate of iron (or copperas,) sulphate of alumina (or alum,) and
sulphur in an uncombined condition. So large a proportion of
these substances is sometimes present, as to render the water’ ob-
tained from the strata in which they exist, absolutely unfit for
use.

It is to the existence of these materials in the strata, that we
are to look for the cause of the disappearance of the calcareous
matter, in the form of shells, which they once evidently contained.
Either of the sulphates above named would exert a rapid decom-
posing action on the carbonate of lime, of which shells principally
consist. The sulphuric acid of the sulphate combining with the
lime of the carbonate, thus converting it into gypsum, while the
carbonic acid would, in great part, escape in the form of gas. That
the gypsum is not now discovered in these beds, is an obvious result
of the comparative solubility of that substance in water; its conti-
nuance in the strata being only possible where a heavy covering of
clay excluded the percolating liquid.

Useless, if not injurious, as these clays are now believed to be
when applied to land, there is reason to think that they are capable,
by a little application of chemical knowledge, of being rendered
truly valuable as an auxiliary manure. The gypsum into which
their enclosed shells were once converted, would doubtless have im-
parted to them a high agricultural value. Can we not replace, if not
all, some portion of this fertilizing material, by mingling the clay with
the more pulverulent shell marls occasionally found in its vicinity?
That this mixture would result in the conversion of a portion of
the shelly matter into gypsum, there can be no doubt; and where
the clay was originally rich in copperas and alum, the amount of the
gypsum thus compounded would be proportionally great. Experi-
ments on this subject are well worthy of being tried, not only with the
clays here mentioned, but with those of a similar nature, which, as
already remarked, occur in the more eastern portion of the Tertiary
districts of the state.

Before the amount of gypsum to be anticipated from such a treat-
ment of these materials can be estimated, a chemical determination
of the proportion of sulphates of iron and alumina must be had, and
to this point future analysis might be usefully directed.

But though much of the Miocene marl] in this district has been
exposed to the destructive chemical agencies above explained, much

’

38

also is found retaining its carbonate of lime in undiminished quan-
tity.

On the lower levels on the river banks, it appears seldom to have
escaped the dissolving and decomposing action of the sulphates,
while in the highlands it may usually be found containing its cal-
careous matter nearly as when first deposited. In King William,
Hanover, Prince George, &c., beds are found in the highlands, at
some distance from the rivers. The fossils they contain are identical
with those of the marl beds farther east, and the materials with
which they are intermixed present no peculiarity important to be re-
marked. Specimens of this Miocene from Hanover, King William
and Prince George, exhibit a good per centage of the carbonate of
lime, and as might be expected, the strata from which they were
taken are usefully resorted to by the neighbouring farmers.

As would be inferred from remarks previously made, the general
level at which this marl occurs, is higher than that of the Eocene,
and here the promise is held out that this latter, even in the high-
lands, would be exposed by excavations carried to some depth be-
neath the lower limits of the former.

In examining the Eocene deposite on the Pamunkey and James
rivers, the interesting geological fact was observed of an actual su-
perposition of the Miocene upon it; and on the Pamunkey, the pre-
cise point was determined at which the Eocene first makes its ap-
pearance above the water-line, being there overlaid by a heavy bed
of the more recent deposite. This occurs at Northbury, and directly
opposite at the plantation of doctor Charles Braxton.

OF THE EOCENE OR LOWER TERTIARY MARL.

The descriptions and facts which will be comprised under this
head, will principally refer to the localities on the Pamunkey and
James rivers, to which especial observation has been directed. At
the same time that their value, as applying to the Eocene district
generally, may be regarded as being sufficiently established by
general geological analogies, as well as such observations upon other
portions of the region, as the present early stage of the inquiries
has allowed me an opportunity of making. No region of eastern
Virginia holds out more certain promise of reward to future inves-
tigation, and none will reap from the research more lasting and im-
portant benefits.

39
DESCRIPTION OF THE EOCENE STRATA OF THE PAMUNKEY.

Rising above the water-line at Northbury, the upper surface of the
deposite is seen ascending with a very gentle slope, as it extends
higher up the river, until at Newcastle it attains an elevation of about
25 feet above medium tide. Beyond this point, with slight undula-
tions in its outline, it continues with but little general deviation of
height from the water-line to near its termination at the junction of
the North and South Anna, where it dips or thins out until lost
immediately on the verge of the coarse sandstone, which there, for
the first time, makes its appearance in massy form. The deposite
appears on both sides of the river, wherever the flats do not inter-
vene, and at the base of the second level, corresponding in position
to its place in the river cliffs in the same vicinity.

On the south side of the river, the deposite has been particularly
examined, at Northbury, Hampstead, Retreat, Washington Basset’s,
Walker Tomlin’s, Mrs. Ruffin’s, Mr. Roane’s and Mr. Wickham’s,
where it terminates. Specimens have been collected from other
localities, either on the river or at the base of the second level: on
the north side, at Chericoke, captain Hill’s, Mr. Nixon’s, Piping
Tree, Newcastle, Dr. Braxton’s and Mr. Fox’s. Specimens also
from various other points on, and remote from the river, have been
procured, and thus a somewhat minute acquaintance with this por-
tion of the Eocene tract has been attained. Towards the southern
boundary of the deposite, the following arrangement of strata occurs,
commencing at the top.

Ist. A stratum of greenish yellow earth containing no shells, but
numerous traces or casts of them, plainly showing that shells were
at one time embedded in the mass. Sulphate of lime or gypsum
occurs in crystals sometimes of considerable size, interspersed
throughout this stratum, which is principally made up of coarse
silicious sand, blended with granules of greensand or silicate of iron.
The thickness of this bed is variable; at Chericoke and Hampstead
it is about two feet; at Retreat from four to five.

2d. Beneath this lies a layer of dark greenish blue or brown earth,
which when dried, generally falls to pieces, and is discovered to con-
sist mainly of coarse silicious sand, and greensand, together with
shells generally in a broken condition. The shelly matter is some-
times entirely wanting, though occasionally it composes a large por-

40

tion of the mass. At Hampstead, the calcareous ingredient exists
in large proportion and ina finely divided state. Frequently, one
or more thin layers of the oyster shell peculiar to the lower tertiary
region occurs in the body of this stratum; a fact remarkably exem-
plified at Piping Tree, and for nearly a mile further down the river,
where the layer of shells froms a hard rocky shelf laid bare at low
tide, and presenting large and perfect specimens of the fossil oyster,
in the midst of the greenish stratum just described.

At Chericoke the stratum rises to about four feet above the water,
and as ascertained by digging, descends to seven feet below the
river shore.

Higher up the stream, these strata attain a greater elevation, and
subjacent beds, not apparent at either of the points above described,
come gradually into view. In these localities we usually find,

Ist. A layer of dark grayish-green or grayish-brown colour, con-
taining multitudes of shells, generally in a perfect state; the fossil
oyster shell already referred to abounding chiefly in the upper part
of the stratum. Beneath this, but frequently separated by no dis-
tinct line of demarkation, we find,

2d. A layer of darker hue, containing less shelly matter, and the
shells chiefly of the smaller kinds; and

3d. A stratum of the same appearance, in which no calcareous
matter can be discovered.

All these strata contain a large portion of the greensand. In the
upper and lighter-coloured beds, the granules of this substance are
very obvious to inspection, resembling in size and colour the grains
of gunpowder, and giving when bruised a bright green stain. In
the lower beds they are more minute, and being intimately mingled
with the other materials present, are not readily recognised, except-
ing by the general greenish character of the mass. These beds also
contain a great deal of Mica in fine sparkling scales. Of the depth
of these strata below the level of the river nothing definite is known,
no extensive excavations having yet been made. At Mr. Wick-
ham’s they are found to rest upon a layer of large pebbles, but this
basis is perhaps not co-extensive with the deposite lower down the
river.

When the upper bounding surface of the Eocene is even and uni-
form, it is always marked by a thin layer of black pebbles, wpon
which there usually rests a bed of olive-coloured earth, or of friable

41

white clay—and in some cases, both these strata, the olive-coloured
being next the Eocene.

This olive earth is of a fine texture, containing but little gritty sand.
Here and there a shark’s tooth in a decomposed condition, or the
impression of a shell may be discerned. The white stratum
abounds in casts, but never presents the shells themselves. It
shows a light trace of gypsum, but in neither of these beds does
there exist any carbonate of lime. From the character of the
organic impressions they contain, they clearly refer themselves to
the Miocene formation.

In some places on the river, particularly where the upper bed of
the Eocene contains gypsum, as at a pointa little below Piping Tree,
a thin layer of ferruginous rock abounding in casts occurs imme-
diately in contact with the Eocene; this also is to be placed among
the strata of the Miocene.

A more distinct conception of the order and extent of the strata
of both the tertiary divisions, as they occur at different points along
the river, will be obtained from the following summaries derived
from observation.

On the north bank of the river in a cliff about half a mile below
Piping Tree, the beds taken in a descending order are,

Miocene.—1. White friable sandy clay, containing fossil impres-

sions, - S - 10 feet.
' 2, White sandy marl with broken shells, - 4
3. Ferruginous stratum abounding in casts, and occa-
j sionally containing the shells themselves, 4.

4, Thin band of black pebbles,

Eocene.—5. Dark greensand stratum—no shells, - 4
6. Rocky shelf of cemented shells of the saddle-
shaped oyster, - . 4
7. Dark greensand strata with small shells, . 2
173

The highest Miocene bed is not exposed at this point, but occurs
a little farther up the river in the character of a dark blue clay with
fossil impressions, on which there rests a thin layer of ochreous clay,
as brilliant in its tints as the finest chrome yellow. This ochre is of
the most impalpable texture when dried, and would be found very
valuable in colouring.
6

42

At Mr. Washington Basset’s, about 44 miles higher up the river,
the bank is precipitous, and presents the following series of strata:

Miocene.—Superficial gravel, - - - 5 or 6 feet-
Thin layer of friable sandy clay with casts, - 3
Olive-coloured earth with shark’s teeth, and a few

casts of Miocene shells, — - - vt

Thin line of black pebbles,

Eocene. —Dark greenish-brown stratum, containing a large pro-
portion of greensand, and in some parts
abounding in shells. The upper portion con-
sists of a rocky mass of cemented shell,
chiefly the saddle-oyster, = - - 20..°

At Walker Tomlin’s, on the south side of the river, immediately
below Newcastle, the beds are,

Miocene.—Friable white clay and sand with casts of shells, 2
Eocene.— Olive earth with pebbles at bottom, - - 6

A dark bluish-green clay, containing a great deal of
greensand, capped by rock as at the former
locality, - - - 25

At Newcastle and William H. Roane’s and Mrs. Ruffin’s estates,
. a similar series of beds occurs, rising still higher above the level of
the stream. About 13 miles above Newcastle, the upper surface of
the Eocene marl has an elevation above the river of more than
thirty feet. The lower stratum consists of the bluish-green clay
before mentioned, containing only a few of the more delicate shells,
and richly abounding in greensand; the upper of a gray calcareous
marl, thickly speckled with granules of this substance. Over the
whole is a layer of the white friable material, with Miocene impres-
sions.

The upper surface of the Eocene usually presents an unbroken
line, though at some places, as at Mr. Fox’s above Newcastle, this
is not the case. The bed here consists of a light-coloured sand and
clay, speckled with the greensand, and containing vast numbers of
the Eocene oyster. Its outline presents numerous cavities and emi-
nences, exactly resembling those which occur in the Miocene de-
posite nearer to the seaboard. A narrow layer of common sand

“enn

.

43

deeply tinged by mixture with greensand, lies immediately upon
this irregular surface, and the whole is covered with a bed of gravel
and sand, with diagonal lines of stratification, indicating the agency
of currents at the time of its deposition.

At Mr. William Wickham’s, the overlying stratum consists of
bands of ferruginous gravel and sand, containing round concretions,
like Geodes, generally filled with sand. Thin seams of iron ore run
along this stratum a few feet above the fossiliferous beds. These
latter, in some places, present a level outline, and are then always
covered by a layer of sandy clay containing much greensand. On
the other hand, where the outline is undulating and irregular, a stra-
tum of gravel rests immediately in contact with the bed of marl.
The size of the gravel thus deposited, as well as the scooped surface
of the bed on which it reposes, indicating the operation of powerful
currents after the deposition of the strata of Eocene, presents an ex-
planation of the absence in these places of the upper bed of this for-
mation, remarked as present in those spots, where there are no such
indications of the action of destructive forces. The matrix of the
fossils is sometimes an olive-coloured clay, sometimes a grayish-green
sand and clay, and sometimes a bluish-black clay, conta ting a large
proportion of the granules of greensand. The depth of the marl is
15 feet.

EOCENE STRATA OF THE JAMES RIVER.

The beds of Eocene on the James river first make their appear-
ance on its southern shore near Coggin’s Point, and thence continue,
except when interrupted by the river flats, to a small distance above
City Point, making a distance following the flexures of the shores of
about ten miles. On the opposite side they have been found at
Berkeley and other points, but as yet this portion of the deposite has
been but little examined.

At Coggin’s Point, Tarbay and Evergreen, the cliffs have a height
varying from 30 to 40 feet. The Miocene marl, which in some
places is seen overlying the Eocene, abounds in scallops and other
shells which make it easily recognised. Beneath this and usually
separated from it hy a thin line of black pebbles, like those occurring
on the Pamunkey, there occurs a stratum of a greenish-red and yel-
low aspect, containing much greensand and gypsum ; the latter
partly disseminated in small grains, and partly grouped in large and
massive crystals. The under stratum, rich in greensand and con-

44

taining a few shells in a friable condition, extends to some depth be-
neath the level of the river, and appears to rest upon a bed of clay
of a lead colour, containing crystals of gypsum. At Evergreen a
stratum of pure white clay rests upon the upper layer of Eocene,
containing, embedded in its lower surface, large groups of crystals,
and seems to occupy the place of the black pebbles before mentioned.
The whole thickness of the Eocene deposite at this point appears to
be about twenty feet. Below as well as above this place, its height
declines until no portion of it is any longer visible above the water
edge.

EOCENE DEPOSITE OF THE POTOMAC, RAPPAHANNOCK AND MATTAPONY, &c.

Although the shores of these rivers have as yet been but little ex-
amined with a view to the structure and arrangement of the various
strata they exhibit, enough has been observed to prove that they are
no less rich in the Eocene marl than the other districts which have
been described. On Potomac creek, and for a great distance below
its mouth, the greensand strata may be seen running along the base
of the cliff; and from specimens examined, there can be no doubt
that the character of the deposite is similar to that of the Eocene of
the James river and Pamunkey. On the Rappahannock, for a con-
siderable distance below Port Royal, the very same appearance is
presented; and the greensand obtained from some of these localities
is in every respect like that from the points already noticed. In some
places on the Mattapony, the occurrence of the greensand stratum
has been ascertained, while in others the beds containing this sub-
Stance are replaced by beds of clay, which, though ‘geologically of
the same (or Eocene) formation, are yet less likely to prove interest-
ing to the agriculture of the vicinity. Minute inquiries throughout
all this district, and throughout the corresponding region south of
the James river, are alone capable of developing the extent and va-
lue of this deposite. Even a great deal yet remains to be done in in-
vestigating localities on the James and Pamunkey rivers, the north-
ern shore of the latter being so far almost unexplored, and the pre-
cise character and value of some of the beds in localities examined
being but imperfectly ascertained.

aman

45

OF THE SEVERAL BEDS COMPOSING THE EOCENE FORMATION.

In treating of the accompanying Miocene in the beginning of this
section of the report, our descriptions have been confined chiefly to
those beds which occur remote from the rivers upon the highlands,
and no mention has been made either of the white friable sand or
_ olive-coloured clay already frequently noticed in describing the over-
lying strata on the Pamunkey. :

The first of these, though once the repository of shells and other
fossils, is now entirely destitute of carbonate of lime. A small quan-
tity of gypsum in a minutely divided state seems to be its only in-
gredient of any value, and the amount of this present in the speci-
mens I have examined is much too inconsiderable to give the mate-
rial any agricultural importance.

The olive earth, which is frequently an extensive layer, has also
lost all the calcareous matter which it once contained; but a further
examination, chemical and geological, of this material, will be required
before its nature can be exactly determined, or the possible applica-
tions of which it may admit can be ascertained.

The upper bed of the Eocene, characterised in most of the locali-
ties by the gypsum which it contains, is worthy of especial conside-
ration on account of this valuable ingredient. In specimens from
the James river, from five to eight per cent. of this substance has
been found in a divided state, at the same time that a considerable
additional quantity in a massive form exists in various parts of the
same stratum. :

On the Pamunkey this stratum is not so thick, and is perhaps less
- abundant in the sulphate of lime. The lower beds, in some cases
containing a marked proportion of shelly matter, and in others hav-
ing almost none, are more especially distinguished by the larger pro-
portion of another and even more important ingredient, to wit, the
greensand. Both on the James river and the Pamunkey, their rich-
ness in this material gives them an agricultural value which perhaps
no proportion of calcareous matter by itself, however great, would
be able to impart. The illustrations of its beneficial effects, and the
general observations upon its employment as a manure or marl,
which will hereafter be presented, will, I think, manifest the justice
of this opinion, and give a sound confidence to those who are dis-
posed to make trial of its powers.

46

EXTENT AND COMMODIOUS POSITION OF THE EOCENE ON THE RIVERS.

One of the most interesting facts presented in the foregoing de-
scription of the Eocene on the Pamunkey and James rivers, is the
great depth and extent of those strata, which, from the nature of
their contents, may be applied to profitable use in agriculture. Beds
of such materials, preserving an average thickness of twenty feet,
extend along the banks of the Pamunkey with occasional interrup-
tions for more than twenty miles.

Their position on the river shore makes them of most convenient
access, and gives additional facilities to the conveyance of the ferti-
lizing materials they furnish to various distant points, while from the
peculiar character of the strata themselves, they are almost exempt
from the usual destructive agencies of the freshets, being of a texture
to withstand with scarcely any loss the most violent assaults of the
sweeping currents by which the banks of the river are so often
overflowed. To this cause we are to ascribe the steep declivity of
the shores in many narrow parts of the river, where the abrading
action of the water, instead of rapidly carrying off the materials of
these strata, has merely served to wear them into smooth and almost
perpendicular precipices rising immediately from the margin of the
stream. :

EXISTENCE OF THE HOCENE BENEATH THE HIGHLANDS, AND THROUGHOUT
THE WHOLE BREADTH OF THE STATE.

The general position and direction of the Eocene beds suggests
another view of great practical importance to this and the neighbour-
ing districts of the state. I allude to the probable, perhaps I may
say certain, continuation of these strata over a wide area, on a level
corresponding to the general depth at which they are found upon
the rivers. In confirmation of this view it may be remarked, that
since the publication of a communication on this subject in the Far-
mer’s Register, the existence of a similar deposite throughout an ex-
tensive district of Maryland, lying in the general direction of our
Kocene formation, has been brought to light, and there is reason for
believing that within the borders of North Carolina, near to the Vir-
ginia line, the same strata are displayed in the banks of several of
the streams. In the belief then that all this extensive band of coun-
try, stretching in a meridional direction entirely across the state,

47

rests upon strata of this description, we are led to regard it as fur-
nishing an immense addition to the resources of the state, and as
holding out to our enterprising farmers situated within its limits, a
new motive to persevering and active research. Let it not be sup-
posed, however, that wherever the Eocene occurs within our state,
it will be found to present the same materials in the composition of
its strata, as have been found in the localities already examined.
Much diversity in this respect may, and probably does exist. On
the Mattapony, as already stated, the greensand is frequently re-
placed by beds of clay of a dark lead colour; while on the Potomac,
Rappahannock, Pamunkey and James, variable but generally large
proportions of the greensand occur, and the probability is, that fu-
ture inquiries will develope similar diversities in the materials of the
beds in other yet unexplored portions of the district. Constancy in
the character of the embedded fossils is all that is necessary to a
geological identity of the formations, and this constancy may exist
at the same time that there is a considerable diversity in the mate-
rials in which they are enclosed. It is almost certain, however, that
throughout a large portion of the region in question, extensive and
valuable beds containing the greensand do exist, and that even in
the highlands they might be reached by excavations descending not
very far beneath the lower limit of the Miocene or ordinary marl.

ON THE VALUE OF THE EOCENE GREENSAND MARL IN AGRICULTURE.

From the descriptions already given of the materials of the vari-
ous beds of Eocene, it will be seen that many of them contain ingre-
dients which have long been recognised as valuable when applied to
land. The gypsum in some, and the carbonate of lime in others,
will at once bespeak the favour and confidence of the agriculturist,
and no observations, either as to their usefulness or mode of applica-
tion, will be necessary to give them the importance they deserve.
But the characteristic and principal ingredient of a large number of
these beds, the greensand, possesses claims to our attention which
are equally indisputable, though not so generally appreciated or un-
derstood. Experiments within our own state on this material, as
furnished by the Eocene deposites, though few, and on a very limited
scale, have been so far satisfactory. But as the marls containing
this substance, which have been employed, have also in most cases
contained a notable quantity of gypsum, or of calcareous matter, all

48

the benefits which they have produced would most naturally and
reasonably be ascribed to those ingredients, already known for their
agency in ameliorating the land. On the Pamunkey the Eocene
marl has long been in use, but chiefly those beds have been selected
for the purpose of marling in which the largest proportion of calea-
reous matter was seen to exist. The lower layers, containing little
or no calcareous matter, have on that account, until lately, been re-
jected as useless, and sometimes when a bed of this description of
considerable extent was found immediately overlying a more shelly
stratum, much trouble and expense have been incurred in its re-
moval, to make way for the excavation of the material beneath. Ap-
pealing to the experience of the farmers of New Jersey, by whom
the greensand, in an almost unmixed condition, has long been ap-
plied for the purposes of a manure, its unrivalled efficacy, and the
permanency of its ameliorating effects, are to be regarded as estab-
lished and unquestionable facts. It is true, that at one time, owing
to the ignorance of those who attempted to make use of it, and the
application frequently of a spurious material resembling it in aspect,
doubts of its value have been excited in the minds of some; but the
extensive and uniform experience of the present enterprising farmers
of that state, gives an unqualified testimony to the rapidity, the
power, and the durability with which it acts.

A comparatively small dressing of this marl, often not exceeding
ten or fifteen loads per acre, is uniformly attended with beneficial
results, and this, whether the soil to which it is applied, be a clay,
or a light sterile sand. As an illustration of this fertilizing property
of the greensand, I will subjoin the following statement quoted from
the report of my brother, Professor Henry D. Rogers, on the geology
of New Jersey, to which work I beg leave to refer, for ample and
satisfactory details relating to the agricultural value of this sub-
stance, as well as for practical suggestions as to the most judicious
modes in which it may be applied:

“When we behold a luxuriant harvest gathered from fields where
the soil originally was nothing but sand, and find it all due to the
use of a mineral sparsely disseminated in the sandy beach of the
ocean, we must look with exulting admiration upon the benefits
upon vegetation, conferred by a few scattered granules of this unique
and peculiar substance. The small amount of greensand dispersed
through the common sand, is able, as we behold, to effect immea-
surable benefits in spite of a great predominance of the other mate-

49

rial, which we are taught to regard as by itself so generally prejudi-
cial to fertility. This ought to exhibit an encouraging picture to
those districts not directly within the limits of the marl tract, where
some of the strata possess the green substance in sensible pro-
portion. It expands most materially the limits of the territory
where marling may be introduced, and points to many beds as fer-
tilizing, which otherwise would be deemed wholly inefficacious.”

If such then be the effects of this material, even under circum-
stances where comparatively little advantage could have been antici-
pated, and if such moreover be the concurrent experience of those
by whom it is daily and extensively employed, we are fully author-
ised in the belief, that in the Eocene beds of our own state, though
in general less rich in the fertilizing ingredient than the secondary
strata of New Jersey, the agriculture of eastern Virginia possesses
a new and most valuable resource. :

The chemical examination of these marls, with a view to precise
results, being a matter requiring much time and labour, has as yet
been carried on only to a small extent. But, a thorough analysis
of all the important varieties and an exact determination of the pro-
portion of the various constituents, especially the greensand, or the cal-
careous matter in different localities, will be a work from which much
practical good may be derived. By the light of such results alone, can
the farmer be safely directed in applying it to the soil, or be pro-
perly guided in distinguishing between a material which is spurious,
and one which will be found salutary in its effects upon the land.

The following results are to be looked upon as approximate de-
terminations, but will serve to illustrate the composition of several
varieties of the marl:

COMPOSITION OF GREENSAND (EOCENE) MARLS.

Doctor Corbin Braxton’s, Silica and alumina, &c, 50
Carbonate of lime, 10
Greensand, 38
Gypsum, 2

Walker Tomlin’s, lower stratum, Silica and alumina, 60
Carb. lime and gypsum, a trace.
Greensand, 40

Conrad Webb’s, Silica and alumina, &c. 30
Carbonate of lime, 45
Greensand, 25

50

Wm. H. Roane’s, lower stratum, Silica and alumina, &c. 50
Carb. lime, 4
Greensand, 46
Gypsum, 3
Tarby, lower stratum, Silica, alumina, &c. 40
Carb. lime, 3
Greensand AY 6
Do. upper stratum, Gypseous earth containing
from 6 to 10 per cent. of
gypsum, and from 10 to 15

per cent. of greensand.
Berkeley, Silica and alumina, &c, 50

Greensand, 50

Viewing these results generally, it is apparent, that while in some
cases the efficacy of the marl would be ascribable in a degree to the
calcareous carbonate or sulphate present in large proportion, in a
great many others the greensand ought to be regarded as the chief,
if not the only agent in the effects. A dressing of many of these
marls to the extent usual in the application of the Miocene shell
marl would scatter upon the soil a proportion of greensand, nearly
as great as the average quota which is at present in use in New
Jersey, and in the richer sorts, a much less proportion would be
necessary than it is customary to apply where the shells abound.

We are struck, in considering the composition of these marls, with
the happy variety of constitution which they exhibit, which, should
there be any specific action of the respective ingredients on particu-
lar vegetables, which there is reason to believe is the case with one
(the gypsum,) will the more completely adapt them to the variety of
crops to which the farmer would wish them to be applied. -

Some caution will be necessary in distinguishing the marls, con-
taining a large proportion of greensand, from dark greenish clays and
sands, which have sometimes been mistaken for them. These clays

are always entirely destitute of fossils; they have an astringent or :

copperas flavour, and generally a strong sulphureous odour, though
a slight smell of this kind is also often observed in the best marls,
The occurrence of small shells sparsely distributed and in a decom-
posing state is very frequent in the good marls, though an almost
total absence of shells is sometimes observed. Fine sparkling scales
of Mica, (not gypsum, as supposed by some,) are generally present
in considerable proportion, and have led those who speculated upon

a aecnupmsmaemauan:mssanpsuiiauaunseaasemaauuauuuamuusnessaneadeniucuesdaieumieacnesieessiihdesusssiuiiaiusaeeusiiuaiaaiaia

errernenemnmmnnta nr

ol

the action of the marl, to ascribe a large part of its efficacy to the
supposed sulphate of lime or gypsum contained in it.. To distinguish
a marl of this kind from the: dark blue Miocene marl, a slight atten-
tion to the embedded fossils will be sufficient. The saddle-shaped
oyster, characteristic of the Eocene, and never found in the later
deposite, would at once determine the bed in which it is found to be
of the former description—while the common scallop or clam, which

is never seen in the Kocene, would indicate the Miocene character

of the bed in which it lies.

In concluding what I have to say upon this important topic, I may
be permitted to throw out the suggestion, that should the deposite
of which I have been treating, be found as extensive in its range
and as useful as a manure as here anticipated, the districts of the state
contiguous to its western limits, as well as the region in which it oc-
curs, might be expected to reap important benefits from its employ-
ment. Parts of Henrico and Hanover, and the lower part of Louisa,
in which no marl exists, would be sufficiently contiguous to the Pa-
munkey deposite to avail themselves profitably of its use, and when
the projected improvements in this region of the state shall present
cheaper and readier means of transportation to the remote parts of
the two latter counties, as well as to a portion of Goochland, it is
not extravagant to hope that this material may be conveyed to those
districts at such a cost as will render it a profitable as it would be
an efficacious restorative to the exhausted and sterile soils to which
ameliorating applications have of necessity hitherto been denied.

To other parts of the state in a corresponding position, perhaps
similar benefits might be dispensed, and thus most of that portion
of the state beyond the reach of the limestone which ranges a little
east of the S. W. mountain, would in time be brought under the
beneficent influence of the marls of the western limits of the Eocene
formation.

REGION BETWEEN THE HEAD OF TIDE AND THE WESTERN FLANK OF THE
BLUE RIDGE.

The various geological features of this extensive division of the
state are peculiarly interesting, andsat the same time difficult of in-
vestigation. To trace the limits of the formation of an undoubted
primary character, occupying the region towards its eastern border,
and to ascertain the extent of the overlying rocks, connected with

52

the valuable bituminous coal of eastern Virginia, is of itself a task
in which much time and industry could be advantageously em-
ployed. To investigate minutely the relations and character of the
various rocks with which the auriferous quartz of the region adja-
cent to the western limits of the former, is associated, and to ascer-
tain the number, direction and relative value of these veins, so
productive in the precious metal, would also be a business requiring
much laborious and discriminating observation; while, in the re-
mainder of the district of which we are now treating, multiplied and
accurate researches, directed to numerous lines across its surface,
would be indispensable to correct views of its geological details ; to
the removal of the many obscurities in which its structure in nu-
merous points is as yet involved, and to- the really useful develope-
ment of its great mineral and agricultural resources. In the brief
period allotted to the reconnoissance, therefore, the attainment of
much minute knowledge regarding this region was not to be antici-
pated, although while aiming at the determination of interesting
points of general inquiry, it was always deemed an important object
to collect useful details, calculated to throw light upon the resources
as well as the structure of this region.

Before entering upon the description of the strata of primary and
other rocks of a very ancient character, of which this region is in
the main composed, it will be most convenient to treat of* the inte-
resting formations, including the bituminous coal of eastern Virginia
as well as of the sandstones overlying the tide water borders of the
primary.

GEOLOGY OF THE BITUMINOUS COAL FIELD INCLUDED IN THE PRIMARY REGION.

Of the extent and exact geographical limits of this truly interest--
ing coal formation of eastern Virginia, too little is yet known to
warrant more than a few words to designate its general position
and relations to the other strata. We shall dwell, however, upon
one or two points connected with its internal structure, of great
moment to all those who are interested in the further developement
and working of its coal seams.

It will be apparent by a reference to the general profile or
geological section across the state, that the sandstones and their
associated coal seams, which make up the formation before us,
rest in a narrow trough in the primary strata. Whether the

53

group is characterised by containing coal to a greater or less
amount throughout its whole extent, is yet a question, and one
which can only be determined after minute and elaborate investi-
gation. Traces of good bituminous coal are detected at intervals
over a space of nearly 35 miles in length, from the South Anna
near its mouth to near the Appomattox river ; but there is nothing
to assure us that the sandstone in which the coal occurs, does not
range, at least in some directions, beyond the limits where the coal
itself thins away and disappears. ‘Towards the central part of the
formation,—namely, within a few miles on either side of James
river,—the coal appears to be thickest ; and it is there accordingly,
where the deposite has alone been worked, that we can collect
facts enough to lead to any general views of a practical bearing
regarding the structure of this coal field. Where our section crosses
it,—namely, through the estates of Mr. Wickham on Tuckahoe
creek,—the width of the coal tract is about four and a half miles.
It seems to expand in width as we follow it to the south side of
James river, being in a section drawn through the Black Heath
mines, probably eight miles across from the eastern to the western
outcrop of the primary strata, which compose the floor upon which
the coal-bearing group reposes. The probability is, that this is
nearly the centre of the basin, and the widest part of it, if we are to
judge from the fact, that the coal exists in greater thickness here
than at any place either further north or south.

The thickness of these coal seams is very variable; the great
lower mass which reposes within two feet of the primary rock, in
the Deep shaft and other adjacent mines in Chesterfield, is estimated
to be 40 feet from its upper to its lower surface. Over this there
is another thinner seam, five or six feet thick, separated by a few
feet of coal shale. A third, still thinner band of coal, is found be-
tween these in some of the mines. Upon the opposite or western
side of the basin, two separate seams are wrought in several of the
mines. At Anderson’s mine, the upper seam varies from from six
to sixteen feet in thickness—the lower, separated from it by 30 feet
of slate and sandstone, is from four to eight feet, and rests almost
immediately upon the top of the primary rock. At Willis’ and
Crouch’s mines, on the south-east side of the coal field north of the
river, there are also two principal seams, the upper being five feet,
the lower about four feet thick, and separated from each other by
11 feet of slate. In both these points as elsewhere, the upper seam

54

is invariably the purest coal. We have thus, at a distance of nearly
10 miles from each other, two localities, showing sufficient corres-
pondence in the relations of the seams to each other and to the adja-
cent strata, to establish the continuity of the same beds across the
whole coal field.

In some of the shafts on Tuckahoe creek, as many as five sepa-
rate seams have been struck, of thickness sufficient to justify work-
ing, and there exist many more of insignificant dimensions which
are neglected. There are good local reasons in several parts of
the coal field on the north side of the river for believing, that the
seams occasionally coalesce, so that two become but one.

We do not conceive it essential to the objects of the present re-
port, to specify anything more respecting the local details of the
numerous mines in this coal field, than is requisite to make its im-
portance and peculiar structure understood.

On the south side of the James river, an old mine, called the
River pit, now deserted, contained at the depth of 130 feet, a seam
of coal 20 feet thick, but which, owing to a close approach of the
granitic floor to the sandstone roof, was so reduced in thickness as
to be abandoned.

Upon the east side of the same portion of the basin in Mills’
mines, the coal varies rapidly in thickness, from almost nothing to
upwards of 40 feet, and in one place to sixty feet, if we include thin
bands of the coal shale. In the Midlothian pit the shaft is 500 feet
in depth, and the workings are carried to the depth of 700 feet below
the soil. The coal is very variable in thickness, being worked
at more than 30 feet, and in some places it is even thicker. In this
mine, as in several of the adjacent ones, we have numerous instances
of the coal filling up hollows as it were in the floor, being accumu-
lated in saucer-shaped basins to the thickness of 40 or 50 feet, and
resting in comparatively thin masses upon the eminences in the same
floor. In some instances, these subordinate basins are almost en-
tirely insulated from the rest of the coal field, and are presented
under features which preclude us from supposing that they owe
their shape exclusively to the numerous faults which intersect the
strata. Upon the north side of the river near Tuckahoe, the coal was
reached precisely in the centre of a small insulated cup-shaped de-
pression. The coal as it was pursued, was found to rise gently on
all sides from the shaft, and also to thin away from a thickness of
four or five feet to two feet towards the edges of this shallow basin,

55

which was several hundred feet in diameter, and but little dis-
turbed from its original nearly horizontal position.

It should be remarked, that while the under surface of the coal
resting almost in contact with the primary rock, assumes its un-
evenness of outline, the upper surface is also affected by similar un-
dulations, though to much less extent, which only goes to show that
the deposition of the coal did not sufficiently fill up the original
inequalities upon the floor, to make a perfectly level surface for the
reception of deposites which succeeded.

Of the nature of the dislocations or faults, too little is at present
known to enable one to generalize or say much upon this truly im-
portant topic. The greatest number of pits being upon the eastern
border of the coal field, it is there that the faults or troubles, as they
are generally denominated in this region, are best seen. Along
this outcrop of the coal, there would seem to extend over a great
space one or more very remarkable lines of dislocation, throwing
up the coal to the west by a heavy fracture, so as to make of the
same seam a double outcrop, and over a distance of perhaps half a
mile, bringing the subjacent granite itself again into view. We wit-
ness, therefore, over a portion of the eastern side of the coal field,
two parallel ranges of collieries, less than a fourth of a mile asunder.
The Black Heath mines, the Union mine and the Deep run pits
are said to lie along the outer crop, though it is questionable
whether one and the same fracture extends over so many miles of
strata. The probability is, that several nearly parallel fractures will
be found traversing this side of the region, and tending to the in-
tricacy and difficulty of successful mining. In fact, three extensive
faults affect the strata near the Black Heath mines, the outer one
causing the upthrow before stated, and the others producing heavy
downthrows to the west.

It would seem, that transverse to these more important and
serious fractures, which generally pursue a direction nearly parallel
to the general line of outcrop of the coal, there are innumerable other
more trivial breaks and displacements, sometimes straight, but of-
tener irregular in direction and dip, which still further intersect the
strata, dividing them into a multitude of nearly detached and broken
basins. An exact knowledge, more particularly of the great lon-
gitudinal faults, is especially desirable for directing with system the
mining operations of this coal field.

There is one general fact of much practical interest disclosed in

56

nearly all the principal mines of this whole coal field—It is, that the
main body of the coal lies either in direct contact with the primary
rocks, or closely contiguous to them. This furnishes a highly im-
portant guide, or in fact the only unerring one, in the prosecution of
new or intricate workings; for, it suggests the utility of making
the primary rock the object towards which the mining should be
pursued whenever a difficulty occurs in regaining the coal displaced
by a fault; for, if we are surrounded by sandstone, we may be
sure that the chief deposite of the coal is to be reached by penetrating
across the strata towards the subjacent granitic floor.

The sandstones being all of them nothing more than the debris
of the subjacent primary strata recemented, they resemble them
occasionally so much as to render it difficult to the inexperienced to
distinguish the two classes of rock; though the discrimination in
this case is all important. The aid of a pocket magnifier will de-
tect a less angular character in the materials of the sandstones
than in those of the primary rock.

The general range or longitudinal direction of the coal field, or
what is the same thing, the line of bearing of the outcrop of the
coal, is nearly N. N. EK. and 8.8. W. The structure of the coal
field is that of a true but very oblong basin, composed of a thick
series of variously constituted sandstones super-imposed upon two
or three seams of bituminous coal, themselves resting almost imme-
diately in contact with the surface of the primary rocks of the sur-
rounding region. Wherever the eastern boundary of the coal field
has been traced, the beds of gneiss or stratified granite are seen to
dip apparently with considerable regularity to the west, or beneath
the coal, and in like manner upon the opposite or western edge of
the tract, the same rock is known to have a general dip under the
coal to the east ; suggesting the notion, at first sight, that the strata
pass horizontally under the middle of the coal field. That this is not
necessarily the case, will appear presently.

The usual angle of the primary strata to the horizon is about
25 or 30 degrees. Between the city of Richmond and the edge of
the coal field at Tuckahoe pursuing a progress westward, the dip of
the strata for the first several miles, is at a gentle angle to the E.
and N. E. varying sometimes to the north. Near the coal, the
point towards which the strata are dipping, is more nearly the N.
W. or occasionally more west. A similar change of dip is seen in
passing over the edges of the strata on the eastern side of the coal

o7

field upon the Chesterfield side of the river. Tracing the dip of the
gneiss rock westward, from the western outcrop of the coal, we
find it to be towards the S. E., or beneath the coal field, and this
throughout a width of several miles in our course west, until we
approach the Beaverdam creek; here, for a short space, the dip is
altered to the west, but the easterly direction is after awhile re-
sumed, as we approach Goochland courthouse. Between five and
six miles further on, or in the vicinity of Little Lickinghole creek,
the dip is over more to the west. These various alternations in the
position of the strata, are specified for the purpose of showing how
probable it is, that the coal strata within the basin were originally
deposited in a valley formed by the meeting of an eastern and
western dip; in other words, upon the edges of the strata com-
posing a synclinal axis, and not upon a horizontally placed stratum
of the gneiss rock. The former view will help us more naturally to
account for the very striking inequalities in the thickness of the bed
of coal resting nearly in contact with the ancient surface of the
primary rock. Had the ancient rocky floor, upon which the materials
that formed the coal were deposited, been the gneiss rock in nearly
horizontal stratification, it is hard to conceive how any subsequent
dislocations of the whole group by upthrows and downthrows could
introduce that remarkable degree of unevenness in the thickness of
the coal seams over the small areas for which this coal field is so
peculiar, Everything lends countenance to the opinion, that the
surface of the primary rock, previous to the deposition of the carbo-
niferous matter, was a valley of rolling outlines occupied by
hollows and elevations, causing the first layers of matter which
were thrown down to be deposited in greater thickness in some
places than in others. As the lowest coal seam is separated from
the crystalline rock beneath by only a very few feet of shale, and in
some cases by none at all, it appears likely that the distribution of
the coal was made unequal in thickness from the very commence-
ment. There is ample proof that subsequently to the consolidation
of an enormous thickness of sandstone over the coal, the entire
series of beds, including the underlying primary strata, were reft
by a number of extensive cracks, producing displacements of the
beds, which combined with the original irregularity in the distribu-
tion of the coal itself, has caused the internal structure of this coal
field to be one of excessive intricacy. These views are stated for the
purpose of indicating the necessity of boring as the best and surest
8

58

means of ascertaining the value of particular parts of the formation.
For it must be plain that the ordinary mode of mining, applicable to
other coal fields, may be ruinously fallacious when applied to this.
The intricacy of the faults,and the changing thickness of the coal,
are features calculated to baffle and defy the anticipations of the
miner. A profound knowledge of the nature and extent of the local
disturbances around him, together with some general rules appli-
cable to all coal mines, may enable him to approximate with con-
siderable accuracy to the depth and position at which he is to meet
the coal seam, but he can form little or no anticipation from knowing
its thickness elsewhere, what its thickness will be when he reaches
it in the new place. In most coal fields he may. The reason of the
difference is, that in the present case the coal lies almost immedi-
ately contiguous to the undulating surface of the primary rocks be-
low, and must partake, especially in its lower surface, of the plain
upon which it was deposited. In most other coal regions the un-
derlying rocks are either sandstones, limestones or slates, themselves
originally horizontal deposites furnishing a level floor upon which
the carboniferous matter would necessarily spread itself in an even
sheet.

What is here said is not intended to throw a damp upon enter-
prise which is pursuing the developement of this coal field; on the
other hand, we regard it as one of the most valuable deposites of
mineral wealth within the area of Virginia. Our duty is by practi-
cal suggestions derived from the best sources within our reach, to
promote a sound direction to the enterprise and capital employed
upon the mineral resources of the state—to teach caution where ne-
cessary, but not to discourage.

The fine qualities of the coal in this coal field, both for domestic
‘uses and manufacturing purposes, together with the very enormous
thickness of the deposite in many of the mines where it is pursued,
hold out an ample guarantee, that if prosecuted upon a correct con-
ception of its internal structure, it must always prove a profitable
region to the quarter of the state in which it lies.

There is one suggestion which we venture strenuously to enforce
—the great importance of preserving specimens of the various
layers of rock penetrated by the shafts which are sunk from time to
time, or in any borings that may be made. The rocks resting above
the coal are less liable to be affected by local variations than the
coal itself, for reasons previously explained—and most important

59

inferences might be drawn as to the depth of the coal, by com-
paring the rocks as they are crossed in succession with sets of
specimens of the same collected from the adjoining mines. Data
will thus be rapidly accumulated, from which we shall one day be
able to infer much better than at present, the extent of certain faults
or downthrows, the nature of which can as yet be only imperfectly
understood from the evidences produced in the workings of the
mines. Nor is it too much to anticipate being able to compute from
information thus derived, the depth from the surface of the coal in
some places in the interior of the basin.

To show the constancy of certain layers of rock in particular dis-
tricts, and their importance as a guide in particular situations, we
may adduce a case given by Professor Phillips of a band of fossilife-
rous rock subordinate to a coal fieldin England. Speaking of a cer-
tain seam in the Yorkshire coal field, generally not much more than
16 inches in thickness, and traceable from near Leeds to the west
of Sheffield, it is stated, “That it would have been impossible to
have traced so thin a seam of coal along so extensive a range,
without some. peculiar facilities, some points of reference more dis-
tinct than the varying quality of the coal, and the still more irregu-
lar fluctuations of the sandstones and shales. This coal seam is
covered by a ‘roof’ unlike that of any other coal bed above the
mountain limestone in the British islands; for, instead of containing
only the remains of plants or fresh water shells, it is filled with a
considerable diversity of marine shells belonging to the genera Pec-
ten and Ammonites, and in one locality, specimens of Orthoceras.
The uniform occurrence of these Pectens and Ammonites through
so wide a range, over one particular thin bed of coal, and in no other
part of the coal strata, is one of the most curious phenomena yet
observed, concerning the distribution of organic remains, and will
undoubtedly be found of the highest importance in all inferences
concerning the circumstances which attended the production of coal.”

We may gather from this the importance of anspeuiieg the sand-
stones for fossil remains, should any exist.

The mining shafts hitherto sunk in this region, have been con-
fined exclusively to the vicinity of the eastern and western outcrops,
from an apprehension, that more in the interior of the basin, the
coal reposes too far from the surface to be readily reached. By fol-
lowing the banks of the James river above the mouth of Tuckahoe
creek, it will be seen that the coal metals,—that is to say, the sand-

60

stones,—overlying the coal, after dipping throughout some distance
at a moderate inclination to the north-west, become gradually
almost horizontal, and continue so over much of the middle space
between the eastern and western boundaries of the basin. This,
certainly, implies the absence of any heavy dislocations affecting the
middle tracts of the coal field, and is one feature calculated to sup-
port the notion of boring for coal in that quarter. From what has
been said respecting the probability of an undulating surface in the
subjacent gneiss or granitic rock, and of the faults which intersect
the region, it becomes by no means improbable, that the coal in the
centre of the basin will be found, in some places at least, sufficiently
adjacent to the surface to admit of being profitably mined. General
analogy would lead us to look for accumulations of coal in that
quarter, if not thicker, at all events as thick, as can be seen near to
either outcrop. But the resources of the middle portion of the coal
field can only be imperfectly guessed at, until there has been
gathered a much larger mass of minute information from the bor-
ders of the region. We do not yet know any thing definite regard-
ing many portions of the limits of the basin, more especially the
western outcrop—and there is moreover much to do in following the
coal where it is already tolerably well known.

The deepest shaft, that of the Midlothian mine in Chesterfield, is
500 feet to the coal; and the workings connected with the same
mine, in consequence of some very heavy downthrows to the west,
penetrate to the depth of 700 feet below the surface. There is some
reason to believe, that still further from the outcrop, there will be
found an upthrow, bringing the coal once more nearer to the soil.
It is possible that a shaft one thousand feet deep, would reach the
coal in several places in the interior of the coal field.

In addition to the invaluable deposite above described, coal veins
have been discovered in Prince Edward and Cumberland counties—
and the rocks accompanying this mineral, are known to extend over
a wide area in this portion of the state. Their thickness, compared
with those of the coal fields previously described, is, however, not con-
siderable—and the seams of coal which have been met with, though
containing a very excellent material, are on a comparatively limited
scale. The probable extent of coal in this district, appears as yet
entirely undetermined, and will remain so until an examination of
this portion of the state has been carefully and minutely made. The
discovery of coal within a small distance of the base of Willis’

61

mountain, recently said tohave been made, derives peculiar interest
from the fact of the existence, in the same vicinity, of hematite and
magnetic iron ores in great abundance.

SANDSTONES OVERLYING THE PRIMARY ROCKS ALONG THEIR EASTERN
BOUNDARY.

Sandstones of various degrees of coarseness are found in many
places along the eastern outcrop of the primary rocks, and extending
for some distance below the head of tide. On the Rappahannock, in
the vicinity of Fredericksburg, considerable exposures of these rocks
are seen, the strata lying nearly in a horizontal direction upon the
edges of the primary rocks beneath. At Falmouth, the two are seen
in contact; the latter forming the bed of the river, and the former
resting horizontally upon them. At the head of the Pamunkey, the
same rocks appear, dipping with some steepness to the east; they
are again met with, gently inclining in the same direction, a short
distance below Richmond, and also in the neighbourhood of Peters-
burg, and at several points in Chesterfield county. Further south,
they occur in the upper part of Greensville, and over a considerable
portion of the county of Brunswick, and, as is believed, in portions of
the adjoining counties.

In composition they are merely a mixture of quartz and felspar,
in rather loose cohesion—the felspar often decaying rapidly on ex-
posure. In some varieties, the rounded pebbles are not larger than
birdshot; in others, they attain a diameter of many inches. In cer-
tain localities, the sandstone has a fine close texture, suiting it for
various useful purposes, and is employed to a considerable extent in
building. The quarries in the neighbourhood of Fredericksburg and
Acquia creek, present beds of great thickness of a homogeneous
rock of this description, of which extensive use has been made in
some of the public edifices in Washington, Richmond, and else-
where. In the superior portion of these beds, Lignites, silicified
wood, and vegetable impressions, are frequently to be seen—all of
which contribute to render the examination of these deposites a sub-
ject of much curious interest to science. Whether these sandstones
be in reality contemporaries of the analogous, though somewhat differ-
ing rocks of the coal measures of eastern Virginia, impressed with
peculiarities as to texture, and included fossils by some circum-
stance of position and exposure in the progress of their deposition

62

—or whether, as has been maintained, they are in fact of a decided-
ly more recent origin, are points only resolvable by cautious and
diligent investigation. >

In connexion with these sandstones and the rocks of the coal
measures, there occur in several places beds of earth sometimes
having nearly the firmness of a soft rock, containing a considera-
ble proportion of calcareous matter. In Prince Edward, where their
existence was first particularly remarked by Dr. Morton, these clays
and semi-rocks are occasionally so liberally impregnated with this
substance as to furnish a strong and valuable marl. At other points,
a mixture of carb. of lime and carb. of magnesia is found in beds
of considerable extent, and having a texture similar to the materials
above described. According to an analysis of a specimen of this
substance from Bear Island, it consists in 60 grains of

Carb. of lime, 31
Carb. of magnesia, 18
Alumina, 3
Silica, ié
Loss, 1

60

The occurrence in many parts of this region, of clays and rocks
thus abounding in calcareous matter, is certainly to be looked upon
as a happy circumstance. Those interested in availing themselves
of the fact, should have no difficulty in the application of these sub-
stances in the raw, or if necessary, in the calcined condition; for,
even should they generally contain any notable proportion of
magnesia, the more enlightened experience of the present day would
seem to show that the presence of that earth is rather favourable
than injurious when associated with lime, and in some cases almost
equal in efficacy to calcareous matter itself.

There is moreover another economical aspect in which this ma-
terial may be regarded. From the large proportion of magnesia it
contains, it would furnish an admirable resource for the manufacture
of that earth in the state of pure carbonate, or of what is at present
an “object of much more extensive commerce, I mean the sulphate of
magnesia, or epsom salts.

63

OF THE PRIMARY ROCKS.

As already stated, the extent of this portion of the state is not
accurately known. Its eastern limit coincides in general with a
transverse line crossing our principal rivers at their lowest falls.
Various species of gneiss rocks and granite are exposed at these
points, some of which are beginning to be known for their valuable
qualities as a material for building. At Richmond these strata occur
in heavy beds inclining at various angles to the east, and are well
exposed along the canal for some distance above the city. The
rock at Richmond is a grayish-white gneiss of great density, and
of such a degree of hardness and toughness combined as to impart
the double advantage of durability and facility of being wrought.
Its predominant constituents are felspar and quartz. Dark mica
is sparsely distributed through it, so that its prevailing colour is a
light gray. It is in consequence of its large proportion of felspar
that the rock in many places is observed to be decayed to so great
a depth below its original surface. Those varieties will be found
most durable for architectural purposes in which this excess of fel-
spar does not exist. At the falls of the Appomattox near Peters-
burg, we find a well characterised variety of granite. It possesses
a coarse crystalline structure, and consists of yellowish-white fel-
spar in distinct crystals, with a smaller proportion of quartz and a
trivial amount of white or light-coloured mica. Other varieties of a
more compact and fine texture occur in the same neighbourhood.
At some distance farther west, in general the rock is a gneiss, con-
taining a much larger proportion of mica. In the upper part of
Goochland, and the other counties at corresponding distances above
the falls, gneiss of a more compact texture prevails. A quarry of
this at Columbia furnishes an admirable building material. Its tex-
ture is nearly that of a compact sandstone, and it is coloured of
various shades of gray from the scales of black mica which it con-
tains. A gneiss of a very peculiar description occurs in Willis’
mountain, Buckingham, associated with several interesting minerals.
The rock is generally of a rich pink or purple, owing to a large pro-
portion of oxide of iron disseminated through it, causing it moreover
to be very ponderous. ‘The mica and augite, which appear to be
large components of the mass, give it a very brilliant aspect, espe-
cially when recently fractured. It is sometimes studded with mi-

64

nute cells, containing hematitic oxide of iron. Nearly the whole of
the principal peak of the mountain is made up of this beautiful rock,
which, rising in the form of a wedge to the height of several hun-
dred feet, presents a narrow wall of nearly vertical strata along the
summit. The dip is west, and the fragments which have tumbled
to the eastern base have rendered this the easiest direction of ascent.
From its hardness, and the indestructible nature of its materials,
this gneiss will some day possess a value independent of that found-
ed upon its colour, which will bring it into use as an article for
building. At the base of the mountain schorl occurs in great abun-
dance, crystallized in long prisms in quartz. Asbestus and kyanite
are also found together, with several other minerals chiefly inte-
resting in a scientific point of view.

Westward of this belt of gneiss the rocks assume various inter-
mediate characters, until at length the truly crystalline structure is
lost, and numerous forms of slate of very peculiar and equivocal
features make their appearance. At what precise points the rocks
of unequivocally primary character terminate, future researches
must ascertain.

In pursuing the line selected for the accompanying profile, the
gneiss, which is found dipping east for some distance beyond the
western edge of the bituminous coal formation, assumes a western
dip which it again changes for an eastern one, after which another
change occurs, and the western dip now continues to the neigh-
bourhood of Columbia. Between this point and Bremo, the rocks
become vertical, and further west, the dip continues with scarcely
any exception, easterly, but very steep as far as the South-west
mountain, and even in many lines almost without alteration, to the
western base of the Blue Ridge. b

The soils of the primary region, except were the rocks accompa-
nying the coal exist, are remarked for the quantity of clay, often of
a very ferruginous character, which they contain. The felspar,
which, as already remarked, enters largely into the composition of
our gneiss and granite, is in some of its forms peculiarly liable to
undergo a decomposition by exposure to the atmosphere. The
alkali contained in it is gradually dissolved out, and the clay and
silica, its other constituents, fall to powder, and thus furnish the
materials for soil. At the same time, the quartz and mica, no longer
cemented by the interposed felspar, also separate and mingle with
the general mass of clay or sand. The Hornblende possessing

65

much oxide of iron and some lime, produces when decomposed, a
deep red earth, which, in virtue of its composition, is generally found
productive.

In accounting for the highly ferruginous soils presented in many
places in this district, as at Beaverdam in Goochland, it might at
first view appear most plausible to regard them as the product of
disintegrated hornblende, derived from the subjacent strata, and
certainly in some localities the colour and qualities of the soil may
be justly referred to this origin. But there are numerous instances
in which the superficial earth or clay is very deeply tinged, while
no rock of this description exists in the neighbourhood. Even over-
lying the sandstone of the coal measures, where the occurrence of
this mineral would be next to impossible, soil of a deep ferruginous
aspect frequently presents itself. Moreover, in general this red
soil forms merely a superficial stratum, often only a few inches in
thickness, while the earth beneath, the obvious product of the decom-
posing gneiss or granite, has a white or gray colour, and scarcely
any mixture of the tint which prevails on the surface. In all these
cases we must look for the source of the red soil in the extensive
region to the west, where nearly all the rocks give rise to it by de-
composition, and we must regard it as having been transported to
the spot on which it now rests, by some of those sweeping diluvial
currents whose action is otherwise attested by evidences of a con-
clusive character. .

The soils containing isinglass or mica, as well as those abounding
in the clays derived from the decomposition of felspar, though in
their natural state rather deficient in their productiveness, have ge-
nerally been found to receive great benefit from the applications of
lime and calcareous manures; and the district in question may reap
great advantage from an extensive application of either. Its vicinity
to the Eocene shell and greensand marls, as already indicated, is
likely at some not remote day, to prove eminently beneficial to its
agriculture, and it were to be wished that the farmers who are in-
terested in its improvement, would promptly take advantage of such
facilities of transportation as are likely soon to alter, for the purpose
of availing themselves of the resources which nature has placed so
completely within their reach.

In the neighbourhood of rocks where the felspar is comparatively
abundant, the disintegrating process gives rise to a clay of a pure
white colour, and almost impalpable texture. This is the Kaolin

9

66

of the Chinese, one of the essential ingredients in the composition
of Porcelain. Numerous rich deposites of it are to be found in this
portion of the state. In Goochland, an extensive bed of this earth
has lately been discovered on the estate of Mr. Triplett. Its colour
is a dull white. Between the fingers it has the smoothness of the
finest flour, and with the exception of a few scattered grains of silex,
the whole mass is a perfectly impalpable powder.

By a careful analysis of some of this earth, I find its composition
to be as follows: In 20 grains,

Silica, 10.76
Alumina, | 6,00
Water, 2.90
Loss, 34
20,00

In numerous places in Goochland, Cumberland, Buckingham, and
other counties similarly situated, the Porcelain earth occurs in ex-
tensive beds, and in many cases in as available a condition as above
described. This fact, taken in connexion with the known existence
of felspar in the same region, points to the probable introduction
at no distant day, of an important branch of manufacture in the
state—I allude to the fabrication of the finer description of China or
Porcelain, in which such excellence has already been attained by the
employment of similar materials in Pennsylvania.

The region on the western borders of that which we have been
describing, is marked by the occurrence of talcose and argillaceous
slates, micaceous and garnet slates, chlorite slates, steaschist, vari-
ous modified rocks, and numerous veins of auriferous quartz. The
precise nature of many of the rocks occurring in this, which for the
sake of distinction, may be called the gold region, cannot be deter-
mined without close and persevering attention.

OF THE AURIFEROUS ROCKS.

A general examination of this district suggests a variety of prob-
lems of a scientific as well as practical nature, which it would be
premature at this time to attempt to resolve. The number and ex-
tent of the quartz veins is one of the most interesting as well as im-

~

67

portant features in the geology of this region, and it is greatly to be
desired that minute observation be directed to the tracing of these
veins through the state as far as practicable; to the determination of
the general value of each vein now wrought, as well as the study
of the efficacy of the various processes adopted for the purpose of
separating the gold from the materials with which it is intermixed.
There can be no doubt, that with the means now most commonly
in use, a large proportion of the precious metal is lost and thrown
out with the gravel from which only the larger masses of the gold
have been separated. At one of the mines visited during the recon-
noisance, the sand and gravel, after having been twice subjected to
the usual process of washing, was found sufficiently productive to
yield five dollars a day to each of the two persons who were washing
it a third time. In some of the mines, more scientific and effectual
means, both of conducting the mining operations and the subsequent
process for separating the gold, have been introduced, and when
these improvements shall have become more generally known, we |
may hope for much more profitable returns than in many instances
have been hitherto obtained. The amazing richness of many of
these veins, has attracted enterprise to this branch of mining to
such an extent, that the exploration of the most promising aurife-
rous veins, has of late been very actively and successfully pursued.

In Spottsylvania and the adjacent/counties, Orange, Louisa, Flu-
vanna and Buckingham, numerous veins have been wrought for
some time; from many of which rich returns have been procured,
and under improved modes of operation a still Jarger profit may be
expected. Any detailed account of the various workings now in
progress would be inappropriate in the present report, even if the
state of our knowledge were such as to warrant statements of a
positive nature. Some account of the structure, position and con-
tents of the veins may be introduced as generally applicable to the
whole.

The material of the veins is a variegated quartz, sometimes trans-
lucent, at others opaque. It is generally of a cellular structure, frac-
tures without much difficulty, and in many instances contains a con-
siderable proportion of water, dispersed through its substance. Its
surface, recently exposed, displays a variety of tints of brown, purple
and yellow, of such peculiar aspect as to resemble a thin lacquer
spread unequally over the rock. The cavities are often filled witha
bright yellow ochre, or hydrated per oxide of iron, which generally

68

contains gold in a state of minute division. Sulphuret of iron, (Py-
rites,) is another accompanying mineral, which in many mines oc-
curs in considerable quantities. At Morton’s mine, (Buckingham,)
it is peculiarly abundant, and there, as in other places, generally
contains a portion of combined gold. In the Union mine, near the
Rappahannock, some of the auriferous veins consist largely of the
Pyrites, which here contains so much of the precious metal as to
render the extraction of it an object of profit. This Pyrites, in all
probability, was at some former period, more generally diffused
throughout all the auriferous veins, and by its decomposition, gave
rise to the per oxide of iron, with which the quartz is always more
or less imbued, while the gold existing in it was deposited in the
cells and fissures of the quartz. Silver is occasionally found in con-
nexion with the gold, and the sulphurets of copper and lead have
been discovered in a few instances in the auriferous rock.

The rocks forming the boundaries of the auriferous veins, vary
very much in different localities. _'Talcose slate, chlorite slate, anda
variety of these, abounding in garnets, are the most usual. They are
commonly of a soft texture, yielding readily to the blast, and even
to the pick or spade sometimes. Instances occur, however, in which
the walls of the vein are of such hardness as to greatly increase the
expense and difficulty of procuring the ore. Of this a striking ex-
ample is exhibited in Morton’s mine, where the rock is removed
with difficulty even by the blasting process, while at Booker’s and
some other mines, its texture is so rotten that it rather presents the
appearance of earth than rock. Veins like the latter, under favour-
able circumstances, would give rise to what are technically called
deposite mines, in other words, collections of clay,and sand and gra-
vel, enclosing a portion of gold, all which materials have been re-
moved by the action of torrents or streams from their original posi-
tion in the vein, to some adjacent ravine or hollow, in which they
have been quietly deposited. The rocks adjacent to the quartz are
often auriferous, and in some instances have been found as produc-
tive as the quartz itself Of this, several striking instances occur in
the mines of Buckingham; and I believe that in many other locali-
ties the same condition would be found to exist.

It has already been stated that nearly all the rocks of this region
dip steeply to the east, and it is found that the auriferous quartz
veins conform in the main to the inclination of the enclosing strata.
The quartz is not, however, to be regarded as an interstratified por-

69

tion of the series, which would imply its contemporaneous origin with
the strata.

The form and position of the veins is rarely such as to justify this
view. Instead of lying in uniform thickness between the walls of
the adjacent rock, and with surfaces of slight irregularity, we find
the auriferous veins in most cases very irregular in their forms, at
one point having a thickness of several feet, at another very near to
the former, contracting so as only to measure a few inches across.
Again, in many cases the vein divides, and the separate portions af-
terwards unite or send off other branches.

The bounding surfaces too, instead of being nearly uniform, as in
the strata of the neighbouring rocks, are rough and broken, sending
off numerous small veins of quartz into the enclosing strata.

In Morton’s mines, the width varies from seven feet to five or six
inches. In Booker’s the vein forks, thins, and as frequently widens.
At the Union mines on the Rappahannock, the breadth varies in
some cases from six inches to nearly three feet.

In fact, from the dimensions of the vein at any assumed point, no
certain inference can be drawn with regard to its extent at other
and remote positions. This irregular structure, while it diminishes
confidence in the constancy of a large and fertile vein, at the same
time furnishes grounds for continuing the examination and prosecu-
tion of one, which by its contraction has become of little or no va-
lue, as an enlargement at a small depth beneath, may reveal an abun-
dance of productive rock.

Another fact of some practical importance, and one which, together
with those above stated, has a direct bearing upon the question of
the origin of the auriferous veins, is this, that although in the main,
the dip and direction of the vein conforms with those of the enclosing
strata, the correspondence is far from being exact, and in many in-
stances, while the inclination of the neighbouring strata remains un-
changed, that of the vein undergoes very striking alteration. At
Morton’s mine, already referred to, the dip near the surface is about
20°, while at some depth beneath it becomes 45°; and similar in-
stances of variation might be adduced by reference to other locali-
ties.

It would thus appear, that these numerous veins of quartz are not
to be regarded as deposites coeval with the regularly stratified rocks
among which they are found, since in that case their position and
structure would exhibit a like degree of uniformity, but as matter

70

which, subsequent to the production of the neighbouring rocks, was
forcibly injected between them by igneous agencies from beneath,
rising in the directions of least resistance, and, therefore, generally,
though by no means uniformly, following the places of stratification
of the rocks through which they passed. Instead, therefore, of con-
sidering them as beds like the adjoining strata, as some writers have
done, we would incline to class them among veins of injection, of
which numerous instances occur in other parts of the globe. We
are the more persuaded of the correctness of this view of their origin,
from the consideration that throughout all the region in which the
quartz veins are found, very peculiar modifications in the structure
and composition of the surrounding rocks are invariably to be ob-
served—modifications for which no adequate cause can be found in
the other igneous rocks which occasionally occur, In the Blue
Ridge, the South-west mountain, and in numerous other lines, it may
always be remarked, that wherever the modified rocks occur, indi-
cating an igneous action, more or less intense, which has wrought a
change in their structure, and induced new arrangements of the in-
eredients of the rocks, heavy veins of quartz are sure to lie in their
immediate vicinity ; while through the body of the rocks themselves,
countless minute veins of the same material are seen diverging from
the principal mass, and imparting various metamorphic characters
to the substances with which they are in contact.

Besides the auriferous veins of the region in which gold occurs,
there exist many other veins of quartz agreeing with those which
have been found productive in nearly all particulars, save that of
containing a valuable proportion of the precious metal. It is highly
probable that none of these veins are entirely destitute of gold, and
in many instances no doubt the prosecution of the vein would lead
to the discovery at other points of it, of an ore sufficiently rich to
reward the labour of the extraction. Indeed, it must be looked upon
as probable, that the auriferous character, more or less, pervades
the quartz veins generally, even as far as their western limit in the
Blue Ridge. The striking similarity in the character of them all,
and the obvious contemporaneousness of their origin, would seem to
give great plausibility to this opinion; and if we are to credit the
statements of the discovery of gold in the western part of Albemarle,
and at one or two other points equally remote from the gold region,
as usually defined, we can no longer doubt the propriety of regard-
ing the Blue Ridge as the proper western boundary of the auriferous

i A CC CL A A OT, EN LOLA et NN tt tS CLL LALA LL, AL AE LL rn ne ae me

OO ICO LLL OLE CLL te LN RC cn a RR

71

rocks. A careful investigation of the numerous large quartz veins
ranging along the valley between the South-west mountain and Blue
Ridge, becomes in this point of view a matter of great importance ;
and should the auriferous character be found pervading these veins,
as is not improbably the fact, the extent and value of the gold re-
gion of the state will scarcely have a parallel upon the globe.

OF THE MICACEOUS AND GARNET SLATES, SILICIOUS SLATE, WHETSTONE
BEDS, ROOFING SLATE, STEASCHIST, IRON ORE, &c. OF THE REGION WEST
OF THE GNEISS,

In pursuing the line indicated in the section, after leaving the
gneiss and hornblende slate, which extend some distance above Co-
Jumbia on both sides of the James river, the rocks met with are
chiefly various kinds of slates and schists, penetrated occasionally
by the veins of auriferous quartz already described, and furnishing
materials for building and other uses. Analogous beds are also met
with in the regions north-east and south-west of that here referred
to—ranging through the state in a belt comprehending what is usu-
ally termed the gold region, and bounded on its western side by the
narrow belt of limestone lying east of the base of the South-west
mountain. The descriptions about to be given of these various
rocks and other materials, though founded upon an examination of
them as they occur in Buckingham, Fluvanna, Louisa, and one or
two other counties in the range, will obviously be applicable, with
some modifications, to the corresponding beds occurring in other
portions of the same belt.

MICACEQUS GARNET SLATE, OR BIRDSEYE MAPLE SLATE.

After leaving the gneiss and hornblende slate a little below Bremo,
we come upon heavy vertical beds of a micaceous slate, in which
are multitudes of half developed garnets, and sometimes crystals of
cubical pyrites—giving to the surface of the rock the appearance of
numerous knots, around which the fibres of the stone are beautifully
curved, so as closely to resemble the shading of the birdseye maple;
and hence, in the absence of any specific designation, the one above
used may be considered as appropriate at least for ordinary pur-
poses. ‘This rock has the lustre and colour of plumbago, and evi-
dently contains much mica. It possesses considerable hardness, and

72

may be separated in the quarry in large regular masses—and hence
for slabs, pavements, and general building use, may be advantage.
ously employed. At the Buckingham iron works, it has been used
in the furnace stack, and has been found to answer well.

The silicious micaceous slate occurs a little west of the former,
and has a sensible dip to the east, though almost vertical. This
rock is of a light yellowish brown colour, contains a small propor-
tion of mica, some felspar, and a large amount of silex, apparently
in grains; and in fact, at first view, presents the aspect of some
sandstones, though probably more nearly allied to the mica slates
than any other known rocks. It may be quarried out in long rect-
angular prisms, with surfaces nearly as smooth as if formed by the
chisel, and from its hardness and durability under exposure, is to be
looked upon as a valuable rock. When intensely heated, it becomes
glazed on the surface, and is used for the floor of the iron furnace at
New Canton.

Associated with these beds, is one containing crystallized garnets
in great numbers, and sometimes of exceeding beauty. This rock
often contains much chlorite, and presents a general greenish aspect.
Large quantities of it have been quarried in building the dam at New
Canton, and a portion peculiarly abundant in the garnets, has re-
cently been introduced in the furnace as an auxiliary flux. The
large proportion of lime contained in the garnets fitting the rock pe-
culiarly for this purpose, while at the same time it yields a conside-
rable amount of iron.

The whetstone beds which occur among the silicious and other
slates, also furnish a material of high value. The texture of this
stone is exceedingly close and fine; it possesses a proper degree of
hardness and great permanency under atmospheric exposure. Its
apparently fibrous structure, and the long shape of the masses which
are separated in the quarry, give it the appearance of a log of wood,
partially decayed. The trial of its qualities as a whetstone, made
in Fluvanna, Rockbridge, and the neighbouring counties, amply de-
monstrate its excellence for this purpose, and in some instances, ex-
perienced mechanics have evinced their sense of its superior value
by laying aside the Turkey oilstone, and substituting this in its
place.

One of the most interesting and valuable of the slaty rocks of this
region, is the roofing slate which occurs in a thick bed west of the
strata which have just been described. This makes its appearance

73

on both sides of the James river, dipping east at an angle of about
80° with the horizon. In Buckingham, the bed is largely exposed
in the neighbourhood of New Canton on Slate river, and the quarry
at present wrought by the enterprising owner, Mr. Sims, yields a
material which will bear comparison with the better qualities of the
imported roofing slate. In texture, density and capacity of resist-
ing atmospheric agents, it can scarcely be excelled by a similar ma-
terial in any part of the world. This quarry was first opened to
procure slate for roofing the capitol; and notwithstanding it has
been thus long known, and its value established, but little further
use has been made of it, until the activity of the present proprietor
has again brought it into notice, The buildings of the University
will soon be furnished with a complete covering of slate from this
quarry. The bed of slate wrought by Mr. Sims, has an average
breadth of sixty yards. The rock splits with great regularity, pre-
senting a smooth surface, and having such strength and flexibility
as to admit of being separated by iron wedges into sheets of 100
square feet, and not more than an inch in thickness. There are
many other places in the neighbourhood, from which slate of the
same kind may be procured, and several small quarries have been
opened. Increased facility and cheapness in transporting this valu-
able article to Richmond and the seaboard, will, no doubt; at some
early day bring it into extensive use in our principal towns in that
direction, and will render the quarrying and preparation of it a pro-
fitable business. During the last year, Mr. Sims brought into a
state for the market, six hundred squares of this slate, at twelve dol-
lars per square; and this, with but few hands and very imperfect
arrangements.

The steaschist or soapstone which occurs west of the slate, and
may be seen near the mouth of Hardware river, both in Fluvanna
and Buckingham, though not as valuable as other beds of a some-
what similar description, to be hereafter described, is nevertheless
capable of being very usefully employed. In hearths, jambs and
other parts about the chimney, it is found to possess useful qualities,
and its texture is such as not only to render it easy of separation
in the quarry, but also to make it readily wrought under the chisel.
At Bremo it has already been brought into use.

Several veins or beds of iron ore exist in Buckingham in the
region of the gold veins and slates, and ore of similar description
makes its appearance in Fluvanna, Louisa, &c. In the former

10

74

county indications of this deposite have been distinctly traced
throughout a line of seven miles, and the proprietors of the furnace
at New Canton have assured themselves of its continuity for two
miles. West of the principal vein is another at the distance of
100 yards: a vein of friable slate dipping east occupying the inter-
val. In the first or principal bed a continuous mass of ore has been
uncovered, whose length is about 60 feet, and average breadth 15.
As yet no certain opinion exists as to the depth to which it r aches
below the surface. This ore is generally embedded in a brownish-
yellow ferruginous clay, and fragments lie scattered over.the sur-
face in the neighbourhood of the bed. Through a long but narrow
belt in Louisa, Fluvanna and Buckingham, and in fact throughout
the whole length of the gold region, so called, these surface indica-
tions may be traced. The ore is a hematite, in irregular masses,
sometimes cellular and frequently mammillary. The cells often con-
tain acicular white crystals of great lustre. The colour of the ore
varies from a yellowish to a blackish-brown. Its hardness in differ-
ent localities also differs, and in the immense mass above described,
is such as to render blasting necessary. There is some difference
as to the proportion of oxide of iron contained in the ore from
the two veins near New Canton, and a mixture of both varieties of
ore has been advantageously used in the furnace now in successful
operation. As early as the revolutionary war iron was manufactured
from the Buckingham ore, but until recently this valuable resource
_has been almost entirely neglected. The limestone on the western
edge of the county furnishes the flux employed in the smelting of
this ore, which, under the superintendence of Mr. Dean of New
Canton, is now conducted on a scale of such extent as to give a
weekly product of between 30 and 40 tons of pig metal, much of
which is of a superior quality. Ore of precisely the same descrip-
tion is found likewise in the gold region above Fredericksburg, and
as in the present instance, in the vicinity of the garnet slate. From
the curious association of this ore with the auriferous rocks, it might
be expected that in the operations of the furnace a portion of the
precious metal would occasionally appear, and accordingly it has
been discovered in fine specks in the cinder of the Buckingham
works. Magnetic iron ore of a very valuable quality occurs at
the base of Willis’ mountain in Buckingham, and is found at seve-
ral other places in corresponding positions.

75

OF THE LIMESTONE AND MARBLE EAST OF THE SOUTH-WEST AND GREEN
MOUNTAINS.

This belt of rock, represented on the profile as it occurs on the
Mechunk creek and in several other places, may be traced with but
little interruption through several counties lying in the range there
indicated. In proceeding south it appears to become broader, and
to be subdivided into several ledges, presenting various aspects in
different localities. Wherever examined it has been observed to
have an eastern dip, in some places steep, in others gentle. In
Albemarle county and at Warminster, its structure approaches to
slaty, and its general colour is bluish-gray, frequently veined with
white crystallized calcareous spar. On the Mechunk, it lies on slate
often of a talcose nature, and its position is such as to render the
labour of quarrying comparatively small. At Warminster it is also
associated with a talcose schist and a white silicious rock of fine
grain and considerable hardness, which has been often. mistaken
for marble. Along the banks of the James river, from this point
to the neighbourhood of Lynchburg, cliffs of the limestone from
time to time are seen, sometimes presenting enormous masses of
the rock, immediately on the water’s edge. The breadth of the belt
exposed in this direction is obviously much greater than farther
north, and the character of the rock in some localities is such as
to render it of the highest value. Near the mouth of Tye river and
on the Rockfish, a true marble is found of beautiful whiteness, and
of a texture which renders it susceptible of a fine polish, as well as of
being readily wrought by the chisel. A few miles from Lynchburg,
in Campbell county, a good marble is likewise found, and limestone
is abundant in the same neighbourhood. A white and very ponde-
rous rock occurs in contact with the calcareous stratum. ‘This is
sulphate of baryta, which from its texture and colour has by some
been supposed to be marble. Farther south these beds of limestone
of various qualities are known to occur, but have as yet been little
examined. The probability is that they are continued throughout
the state in the same general line, perhaps spreading out in approach-
ing the borders of North Carolina. In Bedford county, at a point
considerably west of the general direction of this belt, marble is
said to exist, but no specimen has been procured in the reconnois-
sance. Minute investigation of the region indicated by the localities
above mentioned, and extending entirely across the state, would in

76 :

all likelihood be fraught with valuable results. Leaving out of view
the marbles to which we have already referred, the beds of lime-
stone existing in this district of the state furnish a resource whose
value to the agriculture of a wide tract of country it is beyond our
power to calculate. Every bed of limestone developed in such an
examination ought to become a source of agricultural improvement
to an extensive neighbourhood; and were our farmers once
properly impressed with the value of calcareous matter as a manure,
especially on the soils of the region now in question, an earnest
zeal in the discovery and use of these resources would quickly
become general, and an important district of the state would be
rescued from unprofitable and disheartening cultivation. Lying ad-
jacent to the slaty and micaceous soils east of the South-west moun-
tain and its prolongation, this belt of limestone furnishes the very
material by which under judicious management they may be re-
deemed from comparative sterility. In Orange, Albemarle, Louisa,
Fluvanna, Buckingham, &c., the application of lime procured from
this source might with proper arrangements, and the increased
facilities which are likely to’be afforded to transportation, be made
to effect an entire revolution in the agriculture of the country—and
even in Goochland, and other counties comparatively remote, simi-
lar benefits might be secured at a small additional expense, It is
perhaps not generally understood that the slaty and micaceous (or
isinglass) soils, such as prevail in the districts referred to, are known
to be peculiarly susceptible of improvement from judicious liming.
The experience of farmers in Maryland and Pennsylvania has
amply shown that this is the case—in those states soils thus cha-
racterized are Jimed to a large extent, and always with the most
decided benefit. Experiments made in Albemarle and other places
with the lime procured from the limestone beds of which we are
now speaking, have demonstrated its value upon the slaty soils in
the vicinity, and nothing is wanted to diffuse these benefits exten-
sively through the surrounding country, but a just appreciation of
the utility of liming, the introduction of economical and efficient
modes of burning the limestone, and the selection of such quarries
as from the nature of the rock are calculated to yield a product con-
taining the largest quantity of lime.

A mistaken impression has prevailed, that this limestone always
yields a comparatively poor lime; and to this may in part be as-

77

cribed the little use which has heretofore been made of it, either in
agriculture or building. ;

It will be seen by the following statement of results of analysis,
that the amount of carbonate of lime present in these limestones, is
in some cases large, and that in no instance ean the lime be re-
garded as a poor one, I have annexed a column, showing the
proportion of lime corresponding to 100 parts of the limestone :

Carb. Lime. Lime.
100 of blue slaty limestone—Warminster, 81.4 45.5
100 of blue with white veins, do. 88,4 49.5
100 of blue slaty, Mechunk, 83.2 46.6

The extensive exposures of limestone on both sides of the James
river, existing in the neighbourhood of Lynchburg, New Market and
Warminster, from their very favourable position as regards the
facilities of conveyance, are calculated to become peculiarly valu-
able. Indeed, no position could be found in the state in which lime- —
burning could be conducted on a larger and more profitable scale.
By the introduction of the perpetual kilns now generally used in the
extensive lime-burning establishments of the eastern states, much
fuel would be saved, and all the lime which the rock is capable of
furnishing, would be obtained ; while, by the plan usually pursued,
much wood is wasted, and the limestone, particularly of the slaty
kind, is but imperfectly calcined. These improvements once adopt-
ed, and the better kinds of limestone selected for the kiln, there ap-
pears to be no reason why this favoured region may not be able
to furnish our eastern towns with lime more cheaply than it can be
imported from abroad, at the same time that it is imparting to the
surrounding country the benefits of an improved productiveness,
and a wiser system of cultivation.

To what has already been said concerning the marble of this
region, nothing positive can be added without further investigation.
It may, however, be remarked, that from the specimens already seen,
particularly the white marble from Tye ‘river, there is reason to
hope that this, likewise, may become an object of much value to the
district in which it occurs. The Tye river marble, and one or
more analogous veins, have all the characters of a statuary marble
of fine quality, and should not some peculiarity, as yet unperceived,
prevent their application to the purposes of the sculptor, they will no
doubt be looked upon as very valuable possessions.

78

OF THE ROCKS, ORES, SOIL, &C. OF THE REGION WEST OF THE LIMESTONE,
AS FAR AS THE WESTERN FLANK OF THE BLUE RIDGE.

This extensive district of the state comprises a great variety of
slates, sandstones, schists and other rocks, almost uniformly dip-
ping east, and in general at a very steep angle. Quartz veins are
frequently met with, some of which are believed to be auriferous,
though as yet, no profitable mine of the precious metal has been
opened in them. Beds of trap occasionally occur, the material of
which, from its dark colour and extreme hardness, is usually known
by the name of iron rock. In some portions of the district, horn-
blende enters largely into the composition of many of the rocks,
while in others, tale and chlorite appear chiefly to abound. But it
is important to remark, that amid all the diversities in the mineral
character of the strata, a very general conformability of dip may be
observed, Looking merely to the mineralogical constitution of the
rocks in many localities, an impression of the undoubted primary
character of this district would naturally arise. But when a more
general exploration of the region discloses the existence of extensive
beds of genuine sandstone, and conglomerate rocks frequently in
contact with the former, and having the same uniform inclination,
we are unable any longer to maintain this view. This opinion,
however, would be found incompatible with the results of a more
extensive observation of the rocks, of which this region principally
consists. It would then be found, that a Jarge portion of its area is
occupied by beds of genuine sandstone and conglomerate rocks, and
that the chief part of those strata, which at first view might be re-
garded as crystalline and primary in character, are in reality mo-
dified forms of sandstones and conglomerates, which, through in-
tense igneous action, have been made to assume appearances more
or less closely resembling those of rocks of the latter description,
thus disguising, almost entirely in some cases, the original sedimen-
tary structure by which they would be characterised as not apper-
taining to a primary formation. It is the existence of this curious
class of rocks in many parts of the region in question, as well as
the occurrence of occasional beds in which no appearance of the
sedimentary origin can be traced, which imparts to the minute geo-
logical investigation of this part of the state, so much of scientific

79

interest, and at the same time renders the task of such an examina-
tion laborious and difficult.

Whatever may be our view of the origin of the truly crystalline
rocks which occasionally occur throughout this region, numerous
sectional examinations, which have been made with the view of
solving some of the difficulties connected with its geology, have
combined in establishing this interesting conclusion, that by far the
largest portion of its surface is occupied by rocks which do not be-
long to the primary system, while they have, at the same time,
served to display the modifying effects of igneous agents, as
manifested in the changed structure of many of these rocks, on a
scale of wonderful variety and extent.

Early in the present report, allusion was made to the prevailing
errors on the subject of the true geological character of this region,
inclusive of the Blue Ridge; and enough has already been stated in
regard to the structure of the region, to satisfy the enlightened
geologist of the entire impropriety of the designation of primary
which:it has heretofore uniformly received. The further particulars
about to be given relative to some of its rocks, chiefly those of
economical value, will serve still more clearly to evince the inac-
curacy which has hitherto prevailed with regard to the limits of the
great geological subdivisions of the state, as well as to display the
practically valuable results which are linked with an investigation
which at first view appears to be purely scientific in its character.

The rocks of the South-west mountain and its prolongations, and
of the country within a few miles on either side, will first be de-
scribed, after which some account will be given of those lying more
to the west, and in particular of some portions of the Blue Ridge.

Pursuing the line indicated in the profile, after leaving the bed of
limestone, already referred to, we meet with slates and schists in
some places of a micaceous and talcose, and in others of a silicious
nature, and so friable as to be of but little use in building; com-
prising occasional beds of a denser texture, and more resembling
roofing slate. This brings us to the greenish and dark blue argil-
laceous sandstone of which Carter’s mountain, as well as much of
the region on its eastern and western flanks, principally consists.
Beds of gray and yellow sandstone occasionally present themselves
among the darker rock, and these are uniformly of a coarser texture,
and in many cases are rapidly decomposed by exposure to the air
and weather. Quarries of the dark greenish and bluish rock have

80

been opened in many places, and furnish a material for building
which can hardly be excelled either for strength or permanency un-
der exposure. Much of this rock, however, is so hard as to prove
difficult of separation in the quarry. This is remarkably the case
with the green variety, which occurs very abundantly for a mile or
two east of Meriwether’s bridge on the Rivanna. ‘This rock bears
the strongest marks of intense igneous action in its flinty hardness,
and in the large quantity of green epidote which has been developed
throughout its structure. It is, moreover, always intersected by
veins of quarte, so that it would be difficult to find a mass of con-
siderable size, in which many of these veins would not be visible.
It is further to be remarked, that always in the vicinity of these
quartz veins, the rock is hardest, and displays the largest portion of
the green colouring material. All these facts would seem clearly to
point to the quartz, as having been directly concerned in the various
modifications which the rock has obviously undergone. In further
illustration of this view, it may be added, that often in the immediate
neighbourhood of the veins of this material, asbestos, iron pyrites
and other minerals occur, which are known to be thus developed in
various rocks by veins of intensely heated matter injected into them
in a state of fusion. At Meriwether’s bridge and in many other
localities along the range, the greenish-blue rock is studded with
black and greenish spots, indicating an incipient crystallization, and
clearly referable as the geologist would at once perceive, to the
agency of which we have spoken. Here, as well as in all places
where similar evidences of igneous action can he traced, the dip of
the rock becomes confused in consequence of the occurrence of nu-
merous cross joints, such as are often produced in stratified rocks
by an action of this nature. ‘ :

The gray and yellowish-red sandstone, occurring in beds some-
times of considerable breadth, and traversing the country in the
general range of rocks to a considerable distance, are found in many
places to furnish quarries of very: valuable building material. Such
of these beds as are intersected by frequent veins of quartz, are
found to be by far the hardest and most valuable. In the same bed,
examined at points some distance asunder, a great difference in the
hardness and consequent value of the material, may frequently be
observed. Thus, the bed which on the eastern flank of Peter’s
mountain, near Gordonsville, yields a. building stone which comes
from the quarry in long quadrangular blocks of great hardness and

81

durability, presents at the distance of several miles to the south a
crumbling mass, whose value consists in its being useful as a sub-
stitute for sand, or furnishing a good material for the manufacture
of fire bricks. It may, therefore, be found a guide of some value in
the selection of rock for flags or building purposes, to choose such
as, lying in the vicinity of a heavy vein of quartz, and intersected by
smaller ones throughout its substance, is likely to possess the com-
bined advantages of great hardness and durability, and a compara-
tive facility in being quarried, in virtue of the cross joints by which
it most generally and spontaneously divides itself.

In addition to the rocks here described as occurring particularly
in the South-west mountain and its vicinity, various others are pre-
sented both to the south and north of the localities to which the
profile may be considered as referring. Thus, in Orange and in
Nelson and Amherst counties, as well as in the neighbourhood of
Scottsville, in Albemarle, and interruptedly in many other places in
the same general range, a very interesting rock is seen, consisting
of fragments sometimes angular, sometimes more or less water
worn, cemented together by particles of sand, and occasionally a
small admixture of carbonate of lime. This singular conglomerate
has evidently been in part derived from the greenish-blue rock pre-
viously described, with which its larger pebbles or fragments are
obviously identical—and in part from the sandstones and occasion-
ally the limestones of this region. It is in fact the representative,
in this portion of the state, of the Potomac marble, and some of it
when polished would present a surface of equal variety and beauty.
The occurrence of this rock, as here described, obviously marks an
epoch of violent action, in which the neighbouring strata, of which it
may be considered as embodying the ruins, were broken into frag-
ments, and these subjected for some time to the rounding agency of
water, at the bottom of which the coarser and the finer sediments
were at length consolidated into rock. A curious fact, for the first
time observed by my brother, Professor H. D. Rogers, would seem
to show, that in the composition of the Potomac marble, fragments
of limestone may be seen, referable to no nearer source than the
great valley west of the Blue Ridge. In some of the columns in the
senate chamber at Washington, which by their beautiful polish
enable the observer as it were to look into many of the rocky frag-
ments of which they are composed, he detected distinct impressions

11

~

82

of Encrini, a fossil remain abounding in the bed of limestone near
the western flank of the Blue Ridge, and for which we might in vain
look in the limestone previously described as skirting the eastern
flank of the South-west mountain. This curious discovery will at
once indicate the extent of the violent agencies preceding the forma-
tion of this rock, and of the conglomerate which we have regarded
as its equivalent.

In the same region likewise, beds of genuine red sandstone occur,
sometimes of a fine and sometimes of a very coarse grain. This and
a variety of red slate are the chief rocks to be met with between
Warminster and the Folly. Similar beds are to be seen in many
places in Orange and other counties in corresponding positions. In
Amherst, near the Stonewall mills, strata of coarse conglomerate
occur, in which the pebbles have sometimes a diameter of half an
inch.

Near Lynchburg, a very beautiful bluish-gray sandstone is largely
quarried, and in the same neighbourhood very extensive exposures
of various sedimentary rocks may be seen. In nearly all the locali-
ties which have been described, the dip of the rocks is east. At the
latter place, however, a very superb exposure of a silicious and tal-
cose schist is presented on the river bank immediately opposite the
town, exhibiting the feature so strikingly seen among the sandstones
of the North mountain—that of an arch or great bend in the strata,
showing the eastern and western dips at its opposite extremities.

On the western declivity of the Green mountain, beds of steatitic
rock occur, furnishing a soapstone which in all respects compares
advantageously with that now generally in use. A quarry of this
rock has been opened near the residence of Tucker Coles, Esq. from
which slabs and jambs for fireplaces have been procured. The
colour of the rock is a grayish and sometimes greenish-blue, with a
somewhat marbled appearance. Its texture is fine, and with suffi-
cient firmness for any purpose to which it may be applied. It is
capable of being cut and planed with great facility. With the ex-
ception of some of the finer kinds quarried in Vermont, there is
probably no soapstone used in this country which combines the
valuable characteristics of this species of rock in a higher degree.
The recent introduction of anthracite as a fuel in some of our cities,
and the probability that ere long the semi-bituminous and anthracite
coals of the western ridges of our valley will also be similarly ap-

83

plied, impart additional interest to the facts here stated, and render
it highly probable that this rock will at no remote day be brought
into extensive use. In the same neighbourhood are found sand-
stones and schists, all preserving the same general direction and
dipping to the east. |

Throughout the South-west mountain and its prolongations, but
especially on the Buffaloe ridge, micaceous and magnetic iron ore
occur. In the neighbourhood of Stonewall mills, and near the
Buffaloe ridge spring, these ores are peculiarly abundant. They are
also met with largely in the vicinity of the Folly. Hematite containing
some manganese is seen also apparently in veins in a slaty rock at
Reuben Carver's, near the above named mills, and has been supposed
by some to be an ore of silver. The micaceous oxide is generally
blended more or less intimately with the substance of a taleose and
silicious schist, and appears to exist in beds of considerable breadth
amid these rocks. Hitherto, little value appears to have been
attached to the magnetic oxide or oxidulated iron ore which is thus
abundant throughout this region; and yet, judging by the ex-
perience of other countries where this ore is smelted in great quan-
tities, there can be but little doubt that under a judicious system of
operating it might be found a highly valuable material for the manu-
facture of iron. In the highlands of New Jersey, so noted for the
quality and amount of their forged as well as cast iron, an ore of
precisely the same character is used, and the difficulties in smelting,
which appear to have deterred our iron masters from its employ-
ment, are completely overcome.

In many places, within the belt of sii we are now treating,
beds of rock occur, containing green carbonate, sometimes asso-
ciated with a little sulphuret of copper. At the Folly in Amherst,
numerous openings may be seen from which the cupreous rock was
formerly obtained. The amount of copper present in such of the
specimens from this locality as have been examined, though con-
siderable, is not such as promises any high degree of value in the
mass. It is, however, to be remarked, that no positive opinion on
this subject can be formed without much minute examination of all
the places in which this rock exists, as well as a number of analyses
to determine the proportion of copper which it contains. No distinct
vein or bed of copper ore is indicated, but rather an impregnation
of the taleose rock of the neighbourhood, more or less strongly with

84

the above mentioned compounds of that metal. In some of these
places the manufacture of copper has been attempted, but without
the success that would justify a prosecution of the enterprise. In
Orange, Taylor’s copper mine, though opened with high expectations
of profit, has been long abandoned. In the neighbourhood of the
Folly, judging from the number and extent of the excavations which
are seen, we would be led to infer that at the time when they were
made great value was attached to the material which they furnished ;
and if the traditions of the country in regard to the operations of
Colonel Chissel in this region prior to the revolutionary war, may
be received as authentic, that singular and mysterious personage
found in the products of these mines or pits a rich reward for all
the labour and expense which he appears to have bestowed in work-
ing them. It would seem that the cupreous rock was not smelted
by him, but merely ground in a mill, some vestiges of which still
remain, and then packed up and sent to England.

Similar bands of cupreous rock occur in Campbell county on
Beaver creek, about two miles from Ross’ furnace, and also in the
lower end of the county. Pits like those at the Folly have likewise
been opened on the land of Mr. Walker, near the James river in
Buckingham.

Among other interesting minerals occurring in this region are
beds of chloritic steatite and chlorite slate near the Variety mills,
Nelson county ; galena or sulphuret of lead in veins; in quartz at
Rennet-bag creek, Franklin county; sulphate of baryta in numerous
localities ; sulphuret of iron in cubical and other forms, very fre-
quent ; plumbago in considerable masses in Buckingham and Am-
herst; brown oxide of titanium in the neighbourhood of Lynch-
burg.

Many parts of the region of which we have been speaking, as for
instance in the vicinity of Lynchburg, the Buffaloe ridge and the
Folly, are likely to form highly interesting localities to the mineralo-
gist, from the variety and character of the minerals they furnish;
and there is little doubt that interesting developements, in a practical
as well as scientific point of view, will result from the minute ex-
ploration of these and other districts throughout this portion of the
state.

What has now been said in relation to the rocks of the South-
west mountain and its flanks, will with but little modification be

85

found applicable in a general way to the rocks of the Blue Ridge
and the intervening country. Beds of dark green rock containing
hornblende, are occasionally presented. Slates, schists, sandstones
and coarse conglomerates, sometimes but little changed, at others
modified in various degrees, succeed each other as we travel west.
From the South-west mountain, and even in the Blue Ridge, the
beds of rock exhibit the same features and the same general dip to
the east. In the Ragged mountain the rock usually occurring is a
coarse conglomerate or sandstone containing mica, and more or less
modified, so as to exhibit a structure partly crystalline. In a direc-
tion north-west from Charlottesville, a conglomerate containing
large pebbles of angular quartz occurs, and in the same vicinity
fine-grained yellowish sandstone.

Most of these rocks contain a large proportion of felspar, so as
in some cases when disintegrated, to have many of the characters
of a kaolin. A bed of this species exposed near the University, has
been found by Professor Emmet to furnish a material susceptible
of various useful applications. When baked at a very high tempera-
ture, this rock may be made into hones of a very fine and sharp
texture. It admits of being readily carved or turned into crucibles
and other useful implements, for which it is well fitted, by its power
of withstanding heat; and for the same reason it forms a very
valuable fire brick.

With the view of illustrating the structure of the Blue Ridge,
the following descriptive list is presented of the rocks which occur
at Turk’s gap, beginning at the western, and proceeding to the
eastern base of the mountain. A series of beds in the main analo-
gous to those about to be described, may be observed at Rockfish
and Brown’s gap, and other points which have been examined in
the course of the reconnoisance.

In the profile all these rocks are exhibited dipping steeply to the
east, which is their position as observed at Turk’s gap. But at the
Balcony falls, where the exposure of rock is extremely grand and
interesting, the beds on the western flank of the ridge are seen dip-
ping west ; east of this they are seen rolling and arching in a manner
to indicate violent disturbing action, and at length they assume the
ordinary eastern dip. At this place the sandstones of the western
base form beds of great thickness. They are for the most part
grayish, but some Jayers of a dark brown colour may be seen among
them.

Rocks of the Blue Ridge commencing at the western base at Turk’s
Gap.

1. A light gray moderately fine-grained sandstone, met with near
the base of the gap, and extends up a third of the way to the top.
Dip steep to the 8. E,

2. A finer closer-grained rather bluish variety of the same, overly-
ing the former.

3. A lead coloured argillaceous slate, slightly talcose, occupying
another third of the western side of the mountain.

4, A dark-purplish gray and extremely close-textured indurated
sandstone, bearing evident marks of igneous action. This bed is not
thick.

5. A schistose gray sandstone, rather argillaceous, with minute
specks of black sand, and little aceite the size of a pea of transpa-
rent amethystine quartz.

6. A greenish-gray chloritic looking schistose sandstone.

7. A fine-grained dark bluish-green argillaceous sandstone, full
of ineipient crystallization in small vitreous specks, the size of
mustard seed. These specks are small amygdals, the exterior
being a semi-transparent yellowish-green matter like quartz, the
centre being black and granular.

8. An argillaceous sandstone like the former, but containing
more crystalline specks, some of which are of an opaque pinkish-
white.

9. Like the two former, the specks being better devolved, some of
these green and transparent, others pinkish-white, looking like anal-
cime.

10. A very coarse, extremely hard sandstone, round grains of
semi-transparent quartz, in a coarse argillo-silicious paste, evidently
much indurated.

11. A coarse-grained purple sandstone; the rounded gravel of
pink or amethyst coloured quartz, united by a dark paste.

12. A gray purplish porphyritic looking conglomerate, of very
heterogeneous composition, green, red, white, &c. some felspar,
much quartz, and to appearance the matter of the green sandstones
of the ridge.

13. A similar compound approaching to a brick red, angular

\y

87

pebbles of felspar and rounded ones of quartz, &c. in a deep red
paste. The four last specimens belong to the S. E. slope of the
ridge.

14. A white, rather loose and coarse sandstone, the grains united
chiefly by felspar.

15. A coarse sandstone, with rather angular pebbles of quartz
and felspar scattered through a paste very similar to the mass of a
greenish chloritic sandstone.

16. A very light lemon-green epidotic sandstone, with small
specks of quartz and veins or patches of asbestos.

17. A very heterogeneous conglomerate, in aspect somewhat like
the Potomac marble, and identical with the conglomerate before de-
scribed as occurring in the vicinity of the S. W. mountain, &c. the
larger pebbles identical with No. 6.

18. A compact, close-grained purplish-gray sandstone, greatly
altered, having kernels of epidote, and quartz, and deep red blotches,
making it look like heliotrope.

19. Similar to 7, but destitute of the specks.

20. At the eastern base of the ridge, slaty sandstones of a gray
colour.

In presenting the above account of the series of rocks in this por-
tion of the Blue Ridge, I do not wish it to be inferred, that precisely
the same beds in the same order will everywhere be found. Ob-
servation has shown, that in different parts of the range, the rocks
vary somewhat in their character, that while in some places the
sandstones are greatly indurated, and filled with various mineralse
apparently developed by intense heat; in others, they are compara-
tively unaltered, though in all the localities yet visited, some of the
beds exhibit great induration from this cause. We are, however,
to take this descriptive list as representing the important peculiari-
ties of the rocks of the Blue Ridge, and we have preferred thus de-
scribing them in some detail in the order in which they occur, to
attempting to name them according to any supposed or fancied
analogies they may bear to rocks, which are found in the old world.
Such analogies are very vague, and in this as in many other in-
stances in the geology of our country, are calculated to give perma-
nency to error and check a proper spirit of investigation. In the
true spirit of his science, the enlightened geologist has learned to
distrust the generalizations which would always seek analogues to

88

the rocks of one side of the globe, in those of the other, and will,
therefore, prefer a description of the object itself to any appellation
to which, from its supposed resemblances, it might be thought en-
titled.

From the list above given, it will at once appear, that, there is no
material difference between the rocks of the Blue Ridge and those of
the South-west mountain and the intervening country, and that
they seem in the main to be distinctly referable to a sedimentary
origin.

From the above view of the general structure of the ridge, we may
derive a suggestion of some importance in connexion with plans of
internal improvement projected in the state, which is, that the dense
and impracticable character of many of the rocks above described,—
for instance, those from six to twelve,—forbids any attempt at tun-
nelling the mountain, at least in those places which have been ex-
amined, and evinces the necessity, whenever such a plan shall be
proposed in reference to other parts of the ridge, of first ascertaining
whether it does not there also include near its axis materials equally
unfavourable to operations of this kind.

The soils of the region from the Blue Ridge, east as far as the
limestone, are in many places of a deep red or chocolate colour,
while in others they present either a grayish or yellowish hue.
Those of the former kind are usually regarded as most fertile, and
chiefly give value to the lands of Albemarle, Amherst, and other
counties in this part of the state. In accounting for these striking
peculiarities of colour and agricultural properties of the soils in
question, it has been usual to regard them as resulting from the
hornblende, frequently met with in the rocks of this region, which
by its iron would give colour, and by its lime impart fertility, to the
land. There is, however, but a small portion of this deeply coloured
soil traceable to a decomposing rock of the description mentioned,
and by far the largest part of the land thus tinged had been produced
by the disintegration of the dark greenish-blue sandstone, such as
occurs so abundantly in the South-west mountain. Much of the
richest and darkest red soil of Amherst and Albemarle has no horn-
blende in its neighbourhood, while beneath and mingled with the
soil, fragments of the sandstone above referred to, may be seen in
all the gradations of condition, from the hard greenish rock recently
separated from the mass, to the crumbling halfearthy and deeply

89

reddened lump, ready to be reduced by the next winter’s frost into
productive soil. By analysis recently made, I find that both the
greenish sandstone and the resulting soil, contain a sensible quan-
tity, sometimes two per cent. of lime. Should this be found by
further research to be an invariable ingredient of these valuable red
soils, we might, perhaps, be authorised in ascribing their productive
character, at least in part, to its presence; and we would to a cer-
tain extent be enabled to compare these soils with one another in
agricultural value, by chemically examining them for lime.

Portions of the red soil in Nelson and Amherst, arising from the
decomposition of a red sandstone and conglomerate before de- 3
scribed, contain lime in a still more considerable proportion. The
rocks from which they are procured, in some instances, present up-
wards of six per cent. of carbonate of lime. A specimen recently
examined, yielded me in one hundred grains, precisely 6.75 grains of
this substance.

OF THE VALLEY OF VIRGINIA.

The sectional line crossing this region, to which the profile re-
fers, commences at a distance of two or three miles from the western
base of the Blue Ridge, this being the position at which the rocks
of the valley first become apparent. Of the character of the beds
comprised in this interval, we have no data enabling us to speak
with certainty, inasmuch as the fragments of sandstone derived
from the broken strata of that range, piled upon the subjacent beds
of the valley, entirely conceal them from observation. At other
points along the eastern edge of the valley, the interval thus hidden
from examination is not so wide, but in no place hitherto observed
have the rocks of the valley and those of the Blue Ridge been seen
in contact. This, as yet, undetermined ground, is therefore repre-
sented on the profile by a blank, at the western boundary of which
the valley rocks, where first observed, are represented as com-
mencing. Future observations throughout this curious district are
indispensable to an understanding of the true relation existing be-
tween the formations bounding it on either side, and will accord-
ingly present subjects of geological, and even of practical interest
in the prosecution of more detailed research.

As the profile indicates, beds of slate and limestone, in alternate

12

90

order and dipping almost uniformly to the east, occupy nearly all
the space west from this to the commencement of the sandstones of
the ridges subordinate to the North mountain. Layers of a very
silicious limestone, and bands of sandstone, occasionally occur.
Between Harper’s Ferry and Winchester, two alternations of the
slate and limestone may be observed; the most eastern bed, com-
posed of slate, dipping east at an angle of 80° into the valley of the
Shenandoah, succeeded by a broad range of limestone of a dark
blue aspect, and but little veined, dipping in the same direction, next
to which is another bed of slate followed by one of limestone, both
dipping as before.

Approaching the northern extremity of the Massanutten moun-
tain, the belt of limestone presents interesting peculiarities, some of
which may with great probability be referred to the proximity of
that lofty range. It is here traversed by large veins of calcareous
spar, in general running across the direction of the edges at a con-
siderable angle, and it is thrown off from the flank of the mountain
with a reversed or western dip. The veined condition of the rock
distinctly pointing to a period during which it was subjected to
violent actions, cleaving it into countless fissures, subsequently filled
by infiltration with the pure material of the rock, taken in con-
nexion with its inverted dip along the mountain flank, gives great
probability to the idea that the upheave of this range took place
subsequently to the formation of the rocks of the valley, and that
thus the fissured structure and changed direction of the adjacent
rocks, were merely consequences of the elevation of this enormous
mass. In connexion with this curious point of inquiry, the in-
vestigation of the materials and structure prevailing in the Massa-
nutten mountain, cannot fail to prove interesting to the geology of
the state, Such an examination, moreover, promises more than any
other to reveal the geological relations of the valley with the regions
bounding it on either side, and thus to solve some of the most
curious problems with which the student of our geology at pre-
sent cannot fail to be embarrassed.

In the valleys of this mountain slates and limestones occur, and
rumour intimates that coal even has been found. Beds of a coarse
conglomerate of very peculiar structure, constitute an important
portion of its mass, and furnish the material of mill-stones, now much
in use. Limestone is said to occur on the summit of the Peaked

91

mountain, a part of the Massanutten, and it is not improbably the
fact.

Should coal ever be discovered in this region, it -will probably be
anthracite ; and certainly the character of the rocks of the Massanut-
ten, so far as they have yet been examined, is not adverse, if it be
not favourable, to the opinion that the search for this mineral might
be attended with success,

In passing some distance south and west of Strasburg, the strata
resume their former eastern dip, having here apparently been too re-
mote from the mountain, to experience much violent dislocation or
change of direction when it arose.

In the counties of Rockingham, Augusta and Rockbridge, lime-
stone and slates, alternate as before; the former in some places
passing into veined varieties, and occasionally presenting bands and
beds of marble of a good quality. A roll in the strata, or some
change and irregularity in the dip, will usually be found to attend
the veined or marbled varieties of the limestone, and may be looked
upon as a useful guide in the search for quarries of the ornamen-
tal rock. A bed or beds of hydraulic limestone, runs along the valley
not far from its eastern side, to an extent not yet determined. In
the neighbourhood of Shepherdstown, this rock has been quarried,
and found highly valuable in the formation of water cement. A
similar limestone appears on the North river, about nine miles from
the Balcony falls, and at some intermediate points, but as yet no
analysis has been made of the rocks from these localities, and but
imperfect trials have been made of the lime obtained from them, It
would appear that a limestone of analogous character is found also
in Botetourt county, and even further south.

An analysis of the hydraulic limestone from the neighbourhood of
Shepherdstown, shows it to contain nearly a third its weight of
alumina, while the common limestone of the vicinity, and indeed
of the Valley generally, contains but a small proportion of this
earth. A mere analysis, however, is not always sufficient to de-
termine the value of the material, for the purposes of a cement ;
and should, therefore, be accompanied with direct trials calculated to
test its qualities in this respect. Attention is only beginning to be
directed to this subject, which is one to which, from the character
of some of our great works of improvement, a minute geological
and chemical investigation might be very beneficially directed.

92

It is curious to remark, that in Pennsylvania and New Jersey,
limestone of this description occurs in precisely the same relation to
the other rocks as’ in the region we are now describing; and
from its well known and fairly tested value, as employed in those
states, we may look with confidence to the early discovery of valu-
able beds. of it in numerous parts of the corresponding region in Vir-
ginia. Fortunately for its use too, the anthracite of the North moun-
tain is of that description of coal which has been found by far the
most suitable fuel in preparing it for a cement.

The existence of fossiliferous bands, in some of the limestones
of the valley, is an interesting geological fact, of which no notice
appears hitherto to have been taken by those who have professed
to explore the country with scientific objects. Near Strasburg, on
Cedar Creek, and other points around, the rock displays great
numbers of impressions, of encrini, &c. and some trilobites. At
Mount Meridian mills, in Rockingham, organic limestone likewise
occurs, and what is most remarkable as having hitherto escaped at-
tention, the limestone of Weyer’s cave and the vicinity occasionally
exhibits similar impressions of a very interesting and peculiar
character. Farther west, in the neighbourhood of Mossy creek,
fossils occur in a more silicious variety of limestone, and I have in
my possession a fine specimen of fucus from this locality. Such
bands of fossiliferous rock seem to be of more frequent occurrence
farther south, and are quite common in Botetourt and Montgomery
counties.

The importance of the valley limestones, as furnishing a powerful
lime for agricultural and various other uses, cannot be too highly ap-
preciated ; indeed, it is rather matter for surprise, that the agriculture
of this region has hitherto been suffered to reap so little general
benefit from this great source of improvement completely within its
reach. As yet the application of lime to the lands in this part of the
state is ina great degree restricted to particular neighbourhoods,
while (in many extensive districts) through the want of experience,
and of knowledge respecting its employment elsewhere, the efficacy
of lime as a manure, is regarded with a degree of doubt sometimes
amounting to entire disbelief. An impression that the soils of this
country are already sufficiently impregnated with calcareous mat-
ter, in consequence of the proximity of the limestone rock which oc-
casionally rises. to the surface in the fields, seems more than any

‘ 93

other circumstance, to have led to the erroneous notion that lime
could be of no benefit to the soil. It must therefore be regarded as
a fact likely to affect the opinions and practice of persons entertain-
ing these views, that in a great many cases, the soils of the valley
contain little or no calcareous matter, even when taken from the
immediate vicinity of a limestone rock—a fact which has also been
observed by my brother and myself, in regard to many of the soils
in the corresponding region in Pennsylvania and New Jersey. In
the valley of the former state, lime has long been in extensive use,
and is well known to have been the means of imparting rich pro-
ductiveness to many wide districts in the limestone country which
were formerly regarded as of little value, while in the small belt of
corresponding character in New Jersey, a soil of almost sterile
worthlessness has by the same means been imbued with an extra-
ordinary degree of fertility. Experience-thus ample and satisfactory,
under circuinstances. which can leave no doubt as to the applica-
bility of the results to the valley of our own. state, will, it may be
confidently hoped, impress our farmers in that region universally
with the importance of availing themselves of the invaluable resource
which is everywhere spread around them, and of thus removing
the imputation of indifference to improved modes of agriculture,
which the active enterprise of other regions has already proved to
be of great permanent advantage.

The value of the limestones of our valley, with a view to this
most important of all their applications, may be judged of by the
results of several analyses recently made, from which it appears,
that in most cases, the carb. of lime exceeds 80 per cent., and in
some is largely over 90 per cent. of the whole mass. A series of
analyses, giving the composition of all the varieties of the rock in
numerous localities in each @ounty through the valley, would sub-.
serve one of the important interests of this region, by enabling
the farmers to infer what ought to be the proportion of pure lime
present in the product of the kiln in each locality.

Another valuable material hitherto neglected in this region, is the
travertine or deposite marl which exists in some places in large
quantities. In Jefferson and Frederick, this chalky deposite forms
beds of considerable thickness, mingled with but little extraneous
matter. In Rockbridge, nearly all the streams that empty into the
South river, flow over a material of the same nature; and in fact

94

no extensive district of the valley will be found wanting in this de-
posite. It is in truth a precipitation of the calcareous matter from
the limestone waters, which are universal throughout this region,
and must therefore be looked for as occurring in most neighbour-
hoods where springs thus impregnated are of general occurrence.
Now, it is important to be known, that from this substance a lime
of very superior quality may be made, and that judging by the value
attached in the market to that from the travertine of Caledonia in
New York, the burning of this material in some of our localities
might be attended with very considerable profit ; at all events its
utility in agriculture added to the facility with which in some places
the deposite may be obtained, (no quarrying being necessary to
separate it from the mass,) would render it an advantageous substi-
tute for the limestone of the same neighbourhood. Moreover, it
should be remembered, that in the more friable or powdery state in
which much of it is found, it may, as in Europe, be very beneficially
applied as a marl without being burnt. The immense improvement
which eastern Virginia has derived and is now receiving from
the calcareous manures, must render any illustration of the effects
of this substance altogether superfluous, when it is understood that
in composition it cannot be distinguished from the better qualities
of the pulverulent marls, of which analyses have been given in the
early part of this report. Independent of which, its value has been
unequivocally tested in other countries, where it has been found to
have the most decided ameliorating effects upon land to which it is
properly applied.

From what has been said respecting many of the soils of the val-
ley, it is not to be inferred that they are all devoid of calcareous
matter, or indeed that this ingredient is not very often present in
some proportion, but rather that in few or no instances does it exist
in the soil to such an extent as to interfere with the advantageous |
application of lime or unburnt calcareous manures ; and under these
views, I would urge upon those who are particularly interested in
the success of agriculture in the valley the benefits to be anticipated
from the diligent use of the various resources so abundant and ac-
cessible throughout this portion of the state.

The iron ore of the valley constitutes another of its most valuable
possessions. This, although manufactured into iron in numerous
places, has as yet been the subject of no systematic geological and

ee ee me oe

95

chemical examination, further than the mere determination of its
general features, and some of its qualities in the furnace. An ex-
amination of the composition of all the principal varieties now in
use, as well as the determination of the relations of the deposite geo-
logically with the rocks among which it is found, would furnish mat-
ters of inquiry, whose practical bearing upon a valuable branch of
industry in this region, will be promptly and fully recognised by all
who are interested in its success. For, although the tact of the ope-
rator, in this as in almost every department of the arts, is necessary
to the profitable pursuit of the manufacture, those engaged in the
smelting of iron have long been sensible, at least in other countries,
of the high importance of such suggestions as are furnished by a
chemical examination of the ores upon which they operate, and a
geological investigation of the positions in which the beds of ore oc-
cur. The ores almost exclusively in use are hematites of various
aspects, known under the names of honeycomb and pipe ores—
many of which yield a metal of the very finest character. The fa-
cility of smelting, as well as the quality and amount of product, va-
ries of course with the description of ore employed—and from the
want of such knowledge as has been just referred to, the difficulties
of the process in some places have almost put a stop to the opera-
tions of the fnrnace.

A new interest attaches to this branch of industry, at least in some
portions of the valley, from the recent discovery in the immediate
neighbourhood of the iron, of beds of a semi-bituminous dry coal,
which, if we may trust to the indications of its composition, may
hereafter be employed as a most efficient and profitable substitute
for charcoal in the furnace. Of this coal, as it occurs in the Ca-
tawba mountain, and at other points in the valley, but little as yet
is known; but should the hopes excited by analyses which I have
recently made of specimens from the former locality, prove to be
well founded, a new -impulse will be given to the iron manufacture
in that district of the state, and rich rewards be Protianedte to the en-
terprise of capitalists who engage in it.

Of the various objects interesting to the mineralogist, which are
to be found in this region, but little definite knowledge has yet been
attained. We may, however, mention carbonate and sulphate of
baryta, octahedral and dodecaedral sulphuret of iron, pellucid quartz
and crystallized selenite, as occurring more or less abundantly in

96

different places. Of the lead ore, gypsum, &c. of the south-west, we
will speak hereafter.

The numerous extensive caves occurring in this region, form one
of its most curious and interesting features, and serve to illustrate
some of those geological and chemical agencies to which allusion has
been made in explaining certain facts connected with formations in
other parts of the state. Thus, in the rich and variegated crystal-
line deposites and concretions, which render some of the caves ob-
jects of so much curiosity to the visiter—the solvent action of water
upon the various kinds of rocks composed of carbonate of lime, and
the ready tendency of the dissolved matter to separate in a pure and
crystallized condition, are both beautifully displayed, while the round-
ed surfaces of the rocks within the caves, and the generally curved
contour of the various apartments, give evidence of the wearing, as
well as the dissolving energy of subterranean streams. Usually
some disturbance of the rocky strata will be seen in and around
these caves; and in the various fissures and deep clefts naturally
accompanying such dislocations of the strata, we are furnished with
a ready explanation of the means by which the agent that has thus
scooped them out, originally obtained access to the surface of the
rock.

OF THE NORTH MOUNTAIN AND ALLEGHANY REGION.

The numerous ranges of mountains which lie beyond the general
limits of the valley, present several features of great practical, as
well as scientific interest. In the profile view, a section of the Lit-
tle North mountain, as presented west of Mossy creek in Rocking-
ham, terminates the line of observation first examined; and the pro-
file is resumed at a point farther south, in a direction from Coving-
ton across the Great North mountain into Rockbridge. The lesser
ranges of mountains which first interrupt the general undulating sur-
face of the valley, known by the various names of Little North
mountain, Catawba mountain, &c., indicate the commencement of a
series of rocks entirely distinct from those occurring in the valley,
being composed of sandstones and conglomerates, and of shales
subordinate to the veins of anthracite and semi-bituminous coal,
which here discover themselves. The dip of these, so far as ob-
served during the reconnoissance, is somewhat steeply west, as re-

97

presented in the profile. A similar direction of the strata is also
seen in the range of the North mountain in Rockbridge and else-
where, but as exhibited in the section of Brown’s ridge and the Mill
mountain, the dip is east. The rocks composing the North moun-
tain at the place represented in the section, are chiefly sandstones of
different hues and textures, with a reddish shale appearing towards
the eastern base. Ascending by the eastern side, after passing these
shales, we meet with red and gray sandstones; then deep red sand-
stone with occasional seams of a shale interposed, to near the sum-
mit, where we find a heavy stratum of white pinkish sandstone ex-
posing an extensive bared surface, which dips N. W. On the west-
ern side following the winding of the spurs, the pinkish variety of
rock is succeeded by gray, and thence tracing the mountain to its
base, the red and gray varieties appear with changing dip, such as
would be explained by the structure indicated in the profile view of
this side of the mountain. Pursuing a western course, we find slate
dipping to the west for some distance from the flank of the mountain,
but assuming an eastern dip as we approach the base of Brown’s
ridge, where a bed of limestone, with a correspondent dip occurs,
after which we come upon the gray and reddish sandstones com-
posing that ridge, which also dip in the same direction.

There being no reason for doubting the identity of the rocks in
the North mountain and Brown’s ridge, we are led to infer, that im-
mediately at the base of the former there exists a western dipping
limestone similar to that with eastern dip at the base of the ridge,
but not having detected it in consequence of its being concealed by
the fragments of rock collected there, it is not indicated in the figure.
The series of rocks thus far, commencing with that which in the ho-
rizontal disposition, must have been the lowest, would, therefore, be
sandstone, limestone, slate; and this order we shall find prevailing
for some distance farther west. The sandstones of Mill mountain,
like those of Brown’s ridge, dip east, and are separated from the for-
mer by an intervening valley of slate, the western portion of which
is seen dipping in conformity with the rocks of the Mill mountain,
but in the eastern part no rocks in sifu could be seen on account of
the mass of fragments by which they were covered up. From the
precipitous escarpments of the two ridges here described, the appa-
rent identity of those rocks of which they consist, and other striking
circumstances in the features of the valley, there can be but little
13

98

doubt that lines of fault, giving to the strata of sandstone, limestone
and slate, originally horizontal, an eschellon position, have occasion-
ed this repetition of the rocks of the ridge in the Mill mountain, pre-
serving their dip in the same direction; or more familiarly speaking,
these two ridges were thrown up from their horizontal position un-
der such an action of the dislocating force as not to elevate the rock
on the western side of each; and, therefore, not to present any strata
having a counter or western dip. To present this principle, which
is familiar to geologists, in another point of view, the rocks of the
Mill, Brown, and North mountain, being rocks of sediment, and hav-
ing, therefore, been originally horizontal, or nearly so, formed one
continuous bed, the sandstone lying beneath, the limestone next, and
the slate upon the surface. The disturbing force throwing up the
sandstones of the North mountain, gave them a western dip, while
other forces dislocating the strata to the west, gave them the parallel
but not continuous positions which they now display. Instances of
this kind of disturbance are among the most usual in geology, and
would readily be inferred by those versed in the subject to have oc-
curred at the points here described, by a simple view of the profile
itself.

But it is thought that the explanation above given will aid the ge-
neral reader, for whom the report is chiefly intended, in understand-
ing the delineation of this portion of our line. West of the Mill
mountain to near the base of the Warm Spring mountain, we pass
over slates occasionally exposing the subjacent bed of limestone, but
throughout this valley scarcely a glimpse of the sandstone which lies
still lower can be had. At Bratton’s Ridge, the limestone comes
boldly out with an eastern dip, and at some distance beyond, a turn
not delineated having occurred in the strata, the slate is seen dipping
in the opposite direction. This brings us to the little valley of the
Millboro’ Sulphur spring, which here issues from the pyritous slate
—and now the slate is found dipping to the east until another change
brings up the limestone into view near the Blowing cave, and the
dip becomes west again; after which, with several rolls or undula-
tions as seen in the Cow Pasture hills, it settles into an eastern dip,
which continues to the boundary of the slate near the base of the
Warm Spring mountain. Here limestone oceurs dipping with the
slate, and this brings us upon the debris piled upon the skirts of this
lofty range. As the structure of the Warm Spring valley will re-

treet AL OE LLL LLL LL

99

ceive an especial notice, I will defer any further description of the
profile for the present.

The region to which the portion of the profile just deseribed refers,
abounds in objects of practical as well as curious interest,

The coals of the Little North mountain, Catawba mountain, &c.
are among the most prominent of these in an economical point of
view ; and should the reasonable expectations to which their disco-
very has given rise, not be disappointed, will influence in no small
degree the prosperity of one of the most extensive and important re-
gions of the state. From the Potomac to the south-western counties,
the minor ranges of mountains, rising in general along the western
boundary of the valley, are known to include beds of this mineral in
the various conditions of a pure anthracite, and a compound contain-
ing variable but never large proportions of bituminous matter, and
which may accordingly be denominated semi-bituminous coal. In
Berkeley county, on Sleepy creek and elsewhere, openings have
been made, from which an anthracite of the very purest character is
obtained. In Frederick, Shenandoah, Rockingham, Augusta, Bote-
tourt and Montgomery, similar discoveries have been made; the
coal of the four former counties, as far as yet examined, being nearly
identical with that in Berkeley, while that found in Botetourt and
Montgomery contains a considerable portion of bitumen, though far
less than that of ordinary bituminous coal. The veins which have
as yet been examined, vary from three to seven feet in thickness.
That represented in the profile, dipping west into the Little North
mountain, near Coal run, in Rockingham, is about four feet thick.
Several openings at different points in the neighbourhood, present
no perceptible variation in the character of the coal, which is a pure
anthracite, capable, as experiment has shown, of burning with but
little flame, and with the production of a very intense heat. At this
place, and it would appear also in others in the same range, the coal
readily falls into small fragments, exhibiting numerous rubbed and
shining surfaces, leading to the impression, which an examination of
the enclosing rocks would also indicate, that a dislocation of the
strata has occurred, attended with a sliding and grinding action of
the roof and floor of the veins, breaking up and fissuring the included
coal, and occasioning by the mutual attrition of the contiguous sur-
faces that peculiar lustre and striated appearance which they invari-
ably exhibit. In some of the veins, however, this crushing effect

100

appears to have been but little felt, and the coal comes from the vein
in larger and more permanent masses. A further exploration of
those veins, in which the coal has been thus reduced, may bring to
light other portions of the vein, in which comparatively little of this
erinding and crushing action has occurred. For some purposes,
this broken condition of the coal would not impair its usefulness, but
for general sale it would affect its market value.

According to an analysis of the Berkeley coal, executed by my
brother, Professor H. D. Rogers, it contains in the one hundred
grains only 4.94 grains of gray ash, all the remainder consisting of
volatile and combustible matter, This indicates a purity exceeding
that of the Pennsylvania anthracite in general, which at a mean
contains about six per cent. of ash.

In the coal from the Catawba, I have found varying proportions of
bitumen in the specimens from different localities. An average of
these results indicates about 14 per cent. of volatile matter, chiefly
of a bituminous character. This coal burns with but little intume-
scence or swelling, is not much inclined to cake, has no tendency to
splinter when burning, and forms a large amount (upwards of 80
per cent.) of a very superior kind of coke. Allusion has already
been made to the probable value of this mineral, in connexion with
the iron manufacture of this part of the state; but further explora-
tions of these veins, together with careful chemical analyses of the
coal as well as iron ore, and actual trials of the former as to its
qualities in the furnace, are yet required, in order to determine with
certainty the usefulness of this coal in the raw or uncoked condition,
in reference to this branch of industry. In connexion with these
remarks, and more especially as suggesting an important hint to
those who may be endeavouring to bring these dry coals into use
in the way alluded to, it may here be added, that from the great
success attending the use of the hot air blast in France and Eng-
land, where, in some cases, coals in the raw state, of an analogous
character, are employed, the introduction of the same mode of ope-
ration here, holds out the promise of most profitable results ; and it
may be further suggested, that the great efficiency and economy of
the hot air, even according to the trials made in this country with
the ordinary materials used as fuel in our furnaces, ought at once
to excite the attention and awaken the enterprise of all who are con-
cerned in this highly important branch of our manufactures.

101

The sandstones, limestones, and slates of this region, are all of
them convertible to useful purposes. The.pinkish variety of the
former is quarried in the North mountain to furnish hearths for fur-
naces, and has a hardness and sharp grit, which has led to its em-
ployment as a substitute for the more expensive millstones. The
slate is largely impregnated with iron pyrites, and upon exposure to
the air yields a great quantity of sulphate of iron or copperas, as well
as sulphate of alumina or alum. It is for this reason, that the springs
of this part of the state so frequently possess a sulphuretted, chaly-
beate, and acid character, and that some of them are so powerfully
remedial in cutaneous and various other diseases. The celebrated
alum rock on Jackson’s river, consists of nothing but this slate,
which here rises inan abrupt and lofty cliff, forming a semi-circle at
the bend of the river, and presenting a scene which is at once curi-
ous and imposing. Over the surface of the wall-like precipice,
streaks and stains arising from the copperas or ferruginous matter
of the rock, may everywhere be seen, and large nodules of a
spheroidal form, and of the size of a bomb, lie here and there em-
bedded in the mass. Such is the amount of chalybeate and other

saline, as well as sulphureous matter in these slates, that the inhabi-
tants of the country, in lieu of resorting to the springs, of which
some, as the Alum spring, are much in vogue, are accustomed to
make use of the detached fragments of the rock, which in small
quantity will impart to water all the flavour and effects of the springs
themselves.

Chalybeate and sulphuretted springs break forth in various
places from the pyritous slate above described, many of which, as
for example, the Botetourt, Augusta, Rawley, Shannondale, Yellow,
and Alum springs, have acquired reputation for their medicinal vir-
tues. Thermal waters abounding in free carbonic acid and nitrogen
gases, resembling those of the Warm spring valley, occur in some
localities, an interesting example of which may be seen in the neigh-
bourhood of Kaiser’s, in the gorge of the Rich Patch mountain.
Analyses now on foot in relation to the characters of several of
those waters, forbid the publication at present of any decisive re-
sults, but it is hoped, that by an early day some account of their
constitution will be embodied in a treatise on the mineral waters of
Virginia, now in course of preparation.

Of the limestone, it may be merely stated, that it is capable of fur-

102

nishing a lime fully equal to that of the valley, and that the extent to
which it exists in the deep valleys of this region, renders it accessi-
ble for agricultural purposes on almost every farm. Many beauti-
ful and fertile spots possessing the advantages here stated, lie en-
closed among these mountains, which, with facilities of transporta-
tion, must, at some not distant day, be looked upon as choice places
of the state.

Tron ores similar to those of the valley, abound on the flanks of
mountains where the limestone occurs, and many successful fur-
naces are supplied from this source. At Jordan’s furnace, near the
Mill mountain, castings of a very superior quality are made from a
hematite procured in the neighbourhood of Brushy ridge; and at
no great distance above, on the Jackson’s river, the enormous
water power which is here given by the torrent as it makes its way
through the Rich Patch mountain, is in part applied to give action to
the machinery of a large and successful forge. Facts of this kind,
though new to very few, are calculated to fix our attention upon the
great resources in materials and motive power which these wild dis-
tricts of the mountains possess, and thence to illustrate the public
advantages which are at some future day to flow from the establish-
ment of proper facilities of communication with them, and the direc-
tion of wealth and enterprise to the practical es oo of the
riches which they contain. “

Most of the rocks of this region, contain numerous fossil impres-
sions. The bare sandstones on the summit of the North mountain,
seen from the road in passing from Lexington to Covington, display
a great profusion of encrini and other zoophytes; and the sand-
stones of the Mill mountain, Ritch Patch mountain, &c. present
similar vestiges of organic life, together with hollow casts and marks
of shells. In addition to such traces the surface of these rocks oc-
casionally exposes those waving ridges which are known to geo-
logists as ripple marks, and which are referred by them with almost
undoubted certainty to the same causes as are found at the present
day, producing precisely similar markings upon the sandy surface
of the ocean beach. Large exposures of the rocky surface, thus
beautifully rippled, may be seen in numerous parts of the North
mountain, and the other remoter ranges, and under the above view
of the origin of this curious feature of the rocks, are calculated in a

1038

beautiful manner to illustrate the circumstances under which the
strata of this region were deposited.

The slates, particularly those in the neighbourhood of the coal
veins above referred to, present large and perfect impressions of
fern leaves and other vegetable remains; and the limestones are
rich in shells and madrepores of various kinds, and often of uncom-
mon size. Fine specimens of terebratula and caryophyllea may
often be obtained entire.

A curious and imposing feature in the rocky scenery of many
places in this region, is the bent or arched arrangement of the strata.

In following the windings of the Jackson’s river through the wild
and picturesque valleys and gorges by which it makes its way into
the more open region towards the east, this strange conformation of
the rocks is seen in several places, furnishing in the stupendous
elevation of the cliffs, and the massive character of the beds of which
these arches are composed, the most instructive and magnificent
illustrations of some of those agencies io which geologists are accus-
tomed to refer. One of these instances of bent strata, particularly
worthy of observation, is presented in the deep cleft of the Rich
Patch mountain, through which the river makes its final escape from
the rugged region in which its progress has been previously so
much obstructed. Looking from Kaiser’s, or the Forge, the naked
side of this huge defile, towering in a nearly vertical wall, washed
at its base by the impetuous torrent which flows eastward with a
rapid descent, exhibits the grand spectacle of an enormous and
almost unbroken arch of sandstone rocks, rising at its extremities
in steeply dipping lines curving with more gentle inclination to its
summit, and spanning a distance of several hundred yards. Thin
ledges of a very hard variety of the same species of rock project at
the abutments of the arch, and rise along the side of the cliffs in a
nearly perpendicular direction. On the oppositie side the same
position of rocks is seen; but here, in many places, the continuity
of the arch is broken, A similar scene, though on a smaller scale,
is presented in the gorge by which the Calf Pasture river finds a
passage through the North mountain; and indeed it would appear,
that this feature in the position of the strata, is a common occur-
rence in all the mountainous ranges of this wild and beautiful re-
gion.

Proceeding westward in the profile, we come upon the heavy beds

104

of sandstone of the Warm spring mountain, dipping rather steeply
to the east—on the western base of which, we meet with a fossilife-
rous limestone, having the same dip, and therefore lying beneath the
sandstone. Bounding this valley on the west, the Little Warm spring
mountain and its prolongations, exhibit the same rocks in the same re-
lative position, with this important difference, that they all dip west.
The relation of the rocks thus described, and as they are represented
in the section, admits of a simple explanation, by conceiving a violent
upthrow to have occurred along the line in which the valley now
exists. The sandstones thus thrown off on both sides, left the deep
fissure in which the limestones elevated by the same upheaving ac-
tion, were revealed to observation. In this view, the mountains
bounding the valley have been formed merely by the forcible pro-
trusion on either side of beds of sandstone of enormous thickness,
which were originally in a horizontal position—and the limestone
which appears dipping in opposite directions and beneath the moun-
tains, was brought into view by the same agency, although previous
to its elevation it must have existed at a depth of nearly 2000 feet
below the surface. This valley has, therefore, the character of an
enormous fissure, and considering it in that light, we have no diffi-
culty in accounting for the number of thermal springs which it con-
tains. The well established fact that the temperature of the earth’s
strata increases with their depth from the surface, in connexion with
the structure of the valley here described, will at once explain the
elevated temperature which all these springs display, while pecu-
liarities in the mineral ingredients of the subjacent beds, Which it
may readily be imagined would account for the gases which they
evolve, as well as the saline and other ingredients which they hold
dissolved.

In connexion with these views, it is important to remark, that the
fossils and other characters of this limestone distinguish it from
those which are found among the mountain chains to the east or
west, and that it bears a striking analogy to the fossiliferous lime-
stone formerly described as existing in the great valley of Virginia.
Granting the identity of the two, we would thus have the slates and
limestones of our valley occupying a position at great depths below
the various mountains and valleys we have been describing, and
only appearing at the surface where some great uplifting force has

105

operated, as in the Sweet spring eae tossing away the upper and
more recent strata.

Throughout all the region of which this portion of the profile may
be considered as giving merely a local representation, the thermal
waters, in virtue of the carbonic acid contained in them, hold in
solution large quantities of carbonate of lime. The carbonic acid in
quickly escaping from the water by exposure, permits the calcareous
matter to separate, and thus, as the stream proceeds, this ingredient
is precipitated at every step. Hence it is, that we find the channels
of the streams thus impregnated, covered with a hard incrustation,
accumulating in thickness every day, and even the stones and twigs
over which the current flows, becomes encased in a film of semi-
crystalline calcareous matter. Agitation of the water favouring the
escape of the solvent carbonic acid, will also contribute to the ra-
pidity of this accretion, and accordingly it is found, that where the
ripples are numerous, the deposite is comparatively abundant, and
what at first view seems most strange, even the ledges over which
the streams are precipitated in cascades are themselves built up by
additions of the calcareous deposite. The travertine formations of
these valleys, produced in the way we have just described, are in
some cases of immense thickness and extent. That in the neigh-
bourhood of the Sweet springs, has in all probability, a thickness in
some places of upwards of 100 feet, and every year adds slowly to
its amount. At the Falling spring, nearly on the route from Coving-
ton to the Hot springs, a still greater depth of this deposite has been
accumulated, and in various other places throughout this region,
masses more or less considerable of the same curious formation,
may be met with in the valleys, and sometimes even at considerable
elevations on the sides of the hills.

The travertine, like that already alluded to as existing in Jeffer-
son, Frederick and other counties in the valley, is capable of being
made highly useful in pescnlinns, a and of yielding a lime of the great-
est purity and whiteness.

In the mountains west of the point last referred to in the profile,
we discover the ternary series of sandstone, limestone and slate, as
before described; the limestones showing themselves altogether on
the flanks of mountains, and then only occasionally peeping forth.
As represented in the profile, repeated alternations in the dip of the
strata occur in this region, and the structure of the ridges is ge-

14

106

nerally such as to present a dip outwards on both their eastern and
western sides. Progressing westwards, the overlying slate is in-
creased in thickness by the addition of other, and not exactly similar
beds, over which, and generally dipping to the west, we find the
sandstones and slates on the western flank of the Alleghany moun-
tain as presented in the neighbourhood of the White Sulphur springs.
Among the numerous ranges of similar structure to that exhibited
in the profile, and which are usually denoted by the common name
of Alleghany, veins of coal have been discovered in many places,
and the black shale usually accompanying this mineral is of frequent
occurrence. One of these veins is exhibited on the profile, as
seen in the vicinity of Crowe’s, near the base of the Sweet spring
mountain. A similar vein about three miles north of Lewisburg,
furnishes a coal which, according to the trials which have been
made of it both in smith’s forges and in ordinary grates, has been
shown to be of good quality. Most, if not all of these coals, are of
the semi-bituminous character, and are, therefore, not much prone
to cake while burning.

Bands of fossiliferous slate and sandstone are exposed to view in
many places among the mountain ridges of this region. The hard
dark brownish sandstone, generally seen lying in bands of a few
inches thickness, is often largely stocked with fossil impressions.
A single stroke of the hammer will frequently reveal, over an ex-
tensive even surface of the fractured rock, multitudes of such casts,
chiefly the joints of encrini of various species; and so common is
the fossiliferous rock throughout these mountains, that a large pro-
portion of the broken masses met with in the channels of the streams
and in the numerous dry ravines which form the beds of winter tor-
rents, are rich in curious and instructive fossil traces,

The calcareous matter which once formed so large a portion of
these various rocks in the shape of shells and zoophytes, has en-
tirely disappeared, leaving hollow moulds, marking the form and
character of the fossils which have been dissolved away. Yet so
distinctly do these casts preserve all the delicate: lines and marks
of their originals or seals, that they furnish the scientific observer
with a sufficiently definite knowledge of their peculiarities to enable
him to refer them to their proper places in the arrangements of the
naturalist, and by comparing them with the fossils of the other

4

107

strata and other regions, to make important inferences concerning
the geological epoch of their existence.

‘In the limestones of this region fossil impressions are equally
abundant. At Callahan’s and near Crowe’s, the mass of the rock
appears chiefly to consist of solid casts of shells, which, with a little
care, may frequently be detached entire, exhibiting unimpaired, all
the peculiar features of the shells themselves. Perfect specimens of
species of terebratula and productus may be procured at these
and numerous other localities ; and with a little research, a rich col-
lection of fossils may be gathered in almost any part of this region,
comprising a variety of species unknown in the geology of Europe.
Seeing, from the character of these impressions, that the living
beings whose traces are thus engraved upon the rocks, were once
the inhabitants of an ocean, we reflect with wonder upon the curious
geological changes which have occurred since the period in which
the exuvie of these shell fish and zoophytes were gradually accumu-
lated in the sand and mud at the bottom of the sea, and we look with
new interest and astonishment upon the solid texture and towering
height of the rocky strata in which these unequivocal traces of
oceanic life are thus durably impressed.

One of the most valuable of the rocks occurring in this reglon,
is the brownish slate, of which the firm and even surface of our
mountain roads is now frequently formed. The existence of this
admirable material immediately adjacent to the roads in many
parts of this region has already exerted a most happy effect in
their construction and improvement, and has rendered them for
beauty and convenience, deservedly the boast of this portion of the
state.

The numerous mineral springs for which this region is so cele-
brated, and which, perhaps, constitute its most valuable possession,
could not be properly described in the narrow compass of the pre-
sent report; and as injustice might be done by such meagre notices
as it would be possible to introduce, a special description of their
character and contents, and of the geological features of the sur-
rounding country, will be reserved for another publication, now in
progress, in which such details will be given in all the amplitude
they deserve, and from which, should the minute geology of this and
other parts of the state be called for by the legislature, all the im-

108

portant particulars bearing upon this point will be borrowed and
incorporated in a more detailed report.

Among the general considerations in relation to them, which may
with propriety be introduced in this place, it is worthy of remark, that
while the.thermal springs to which we have referred, in treating of
the Warm spring valley and other places, appear to be indebted
for their impregnation chiefly to rocks of a calcareous description,
and are accordingly found in or near such rocks, the sulphuretted
springs now referred to, among which are the White, Red, Salt,
Blue and Gray Sulphur springs, appear to derive most of their in-
eredients from pyritous slates, and will therefore be observed to rise
through or in the neighbourhood of strata of this nature. Of these,
the White Sulphur is the only one which can be regarded as de-
cidedly thermal, its temperature being about 64°, while the others
do not vary considerably from the usual temperature of the ordinary
springs around them.

~ Another point of a general character which may be noticed here,

is the radical difference as to saline and gaseous ingredients ob-
servable between the springs formerly alluded to, and those of
which we now speak. All the waters of the Warm and Hot and
Sweet springs valley, and several others of analogous character,
and highly thermal temperature, discharge considerable quantities
of free gas, consisting of carbonic acid and nitrogen, of which the
latter was first distinctly recognised by myself, and found in general
to be present in very great proportion.

At the same time a Jarge amount of carbonic acid is held in
combination in these waters, imparting the acidulous character for
which some of them are remarked, and giving them the power as
already mentioned of holding large quantities of carbonate of lime
dissolved. This acid impregnation is in no instance more strikingly
manifested than in the waters of the Sweet spring valley, of which,
that of the Red spring about a mile below the principal fountain of
the Sweet springs, presents an amount of the combined gas equal
in volume to about one half of that of the water itself.

Another important distinctive feature in the constitution of the
class of springs here spoken of, is the large amount of the carbo-
nates, principally that of lime, and the comparatively small proportion
of the sudphates with which they are impregnated.

On the other hand, the class of sulphuretted waters as exemplified

109

in the springs previously named, contain but little carbonic acid, and
a comparatively minute amount of carbonate of lime, or other car-
bonates, while they are richly fraught with sulphuretted hydrogen
gas and various sulphates, of which those of lime and magnesia are
present in most considerable proportion. Besides the several points
of distinction above referred to, it may be further added that the
sulphuretted waters are in general impregnated with various organic
matters of very peculiar characters, which by collecting in the
reservoirs and channels of the springs, in mixture with precipitated
sulphur, have, by the various beautiful colours which they impart,
given rise to the different appellations by which the more celebrated
of these fountains are now-known. But while such general re-
semblances as have been described, will be found to prevail among
the several springs of each class as thus characterised, it is at the
same time to be remarked that they possess striking individual
peculiarities, imparting to each an amount and spedies of medicinal
_ agency in some degree appropriate to itself,

Viewed singly in relation to the number, variety and high reputa-
tion of its mineral waters, this region is well entitled to be proud
of the vast resources of which it is possessed. Grouped as these
springs are at moderate distances apart, presenting within the same
district a variety of medicinal character, for which in other
countries, regions remote from each other require to be visited in
succession, placed at a point equally accessible to the inhabitants
of the seaboard and the great valley of the west, and situated in a
region of grateful summer temperature of salubrious climate and of
picturesque and of diversified natural beauties, they are now rapidly
attaining a celebrity for powerful and varied remedial qualities, as
well as for the refined social enjoyments which are annually gathered
around them, destined ere long to eclipse the older reputation of the
famed fountains of the northern states, and to vie even with the
long established character of the most noted of the watering places
of the old world.

Among the valuable minerals of this portion of the state, mention
should be made of the rich iron ores occurring along the ridges in
numerous places, and which, from the frequency of coal seams
among these monntains will one day be brought into profitable use.

Saltpetre is found mingled with the earth in many of the caves
in this region, and has been procured from time to time in con-

110

siderable quantities from this source. This earth or petre-dirt, as
it is called, is obviously a sediment deposited from the waters, for-
merly or at the present time found within the caves, and has some-
times a texture of such impalpable fineness as to indicate that the
deposition took place while the liquid was in a very quiet state. Be-
sides the saltpetre or nitrate of potash, it also contains a large
amount of nitrate of lime, which, by the usual process of mingling
the washings of common ashes with those of the petre-dirt, is by a
direct chemical action converted into saltpetre. Immense heaps of
the earth from which the salt was formerly obtained, may be seen in
some of the wide chambers of the Singing and otner caves, which
there is reason to believe in process of time, will become as rich in
this substance as before.

In the same caves Gypsum is also found mingled with the petre-
dirt, and sometimes enclosing large lumps of it in a thick crystal-
line envelope. In the Organ Cave so much of it is found both in
this condition and replacing the shells originally existing in the
slaty limestone, as to make it worthy of inquiry, whether it might
be turned to profitable use.

Returning to the profile at the point marking the intersection of
Howard’s creek with the line of observation, we remark the com-
mencement of a series of sandstones and slates differing from
those of the Alleghany, and presenting that want of accordance in
the dip which may probably mark the beginning of the great western
series. The rocks of the former kind here exhibit what is called a
diagonal lamination, a structure very general among the sandstones
of the west, and one from which the geologist derives important
hints as to the natural circumstances existing when these strata
were deposited,

On the eastern side of the Greenbrier, is an outlying hill com-
posed of horizontal beds of limestone, resting upon red and green
friable slate. At several points south of this, in a direction towards
the Salt Sulphur springs and Uniontown, this limestone is discover-
ed, and in proceeding some distance towards these points, the hills
as well as valleys present scarcely any other rock but a limestone,
which, judging by its fossils and other characters, may be re-
garded as probably the same as that here represented. Beyond this
point, we meet with west-dipping strata of reddish shale, with a thin
band of limestone on the descent of the hill, approaching Lewisburg.

lil

This brings us into the fine limestone valley, on the confines at
which that town is situated, and here we find the rock dipping at
first very gently to the west, then becoming horizontal with slight
undulations, covered beyond Tuckwiler’s with a soft arenaceous
rock, approaching to sandstone in appearance, but which is in
reality merely the earthy insoluble portion of an impure limestone,
from which the caleareous matter has been all dissolved away.
Beyond this point, the limestone rises with an eastern dip, in the
neighbourhood of Milligan’s creek, after which, at the eastern base
of Muddy Creek mountain, it is seen dipping westward beneath and
mingled with the strata of soft slate, and again appears on the
western side of this ridge near its base, coming out with a dip in the
opposite direction. Finally, it shows itself capping the remoter part
of Brushy ridge, and dipping in a westerly direction, as if prolonged
beneath the heavy beds of slate and sandstone of which the Meadow
mountain is composed. After this, it is not observed to re-appear in
proceeding further west.

Whether as has been supposed, the limestone which has just been
traced, is continuous with the extensive beds of this description
which are spread over a wide district to the south, forming but a
part of one general deposite of which the horizontal limestones in
the vicinity of the Salt Sulphur springs and Uniontown, and even of
the red Sulphur, are merely other portions, it would as yet be pre-
mature to venture upon deciding. No such identity of fossil and
other characters has so far been observed in the rock from these
different districts to authorise a generalization of the kind, and it
must be left to minute future investigation to ascertain the true re-
lations subsisting between these beds.

The extent of the limestone region south and west of Union, is
as yet but imperfectly ascertained. Passing the Gray Sulphur
springs, and proceeding to the south-east side of the Peter’s moun-
tain, we find around the base of the Angel’s Rest and Salt Pond
mountains, and throughout the valley in which Parisburg is situated,
a wide extending stratum of nearly horizontal limestone, much of
which along the New river, is remarkable for containing masses of
silicious rock, embedded in its substance, sometimes having the
horny aspect and hardness of genuine flints. Most of these frag-
ments, however, are irregular in form, and bear a striking resem-
blance to the white and very compact sandstone which is seen pro-
fusely strewing the flanks of the Peter’s mountain for many miles

112

around. In several specimens, I thought I could perceive indistinct
traces of encrini, such as are frequent in that rock. Possibly, how-

ever, these masses may have become entangled in cavities on the
limestone, in which by chemical action, they were subsequently ce-
mented.

One of the most curious objects in the particular district of which
we have just been treating, is the lake near the summit of the Salt
Pond mountain. The erroneous impressions and absurd specula-
tions to which it has given rise, will be accepted as an apology for
the few descriptive remarks which I shall here present. This beau-
tiful sheet of water is situated at the intersection of the Salt Pond
mountain and several of its spurs, and not, as is commonly supposed,
on the top of the mountain. Its height above the base of the moun-
tain, is probably from 900 to 1000 feet, but it is surrounded by steep
and lofty hills on every side, excepting that by which it is approach-
ed, and that through which its waters find a small outlet, falling in
a picturesque cascade of great height, and then flowing rapidly into
the creek below. The outlet appears formerly to have been deeper
than at present, and the extent of the lake was therefore much less
that it now is. Rocks and earth gradually accumulating at the
passage, have dammed the waters up, and hence the trees and
shrubs which grew upon its margin, may now be seen sometimes
standing erect at a considerable depth beneath its surface. Its
length is about three quarters of a mile—its greatest width about
half a mile. By careful soundings from side to side, in many parts
of it, the greatest depth that could be found was from 56 to 60 feet ;
but such was the transparency of the water, that the bottom could
be seen nearly in its deepest parts. No animal is found in it but a
small species of salamander or water lizard.

Of the south-west portion of the state so little is known, further
than the existence and value of its gypsum, lead, salt and iron, that
no general views, even of its important geological features, can be
ventured on with safety for the present. Even the tracing of the
limits of those formations that connect a portion of it geologically
with the great Virginia valley, would as yet be premature; and of
the true character of the more western parts, we have no means at
present of forming any accurate opinion. Hence, in introducing the
few remarks relating to its structure and economical resources,
which I shall presently bring forward, little or no regard will be paid
to any imaginary lines of demarkation, which might be conceived

113

separating from each other the distinct geological formations which
there is but little doubt that it includes.

Through an exclusive attention to the direction of the drainage of
the northern and eastern portions of this division of the state,—as,
for example, in Montgomery county,—the designation of Alleghany
has been very strangely and unphilosophically applied to a compa-
ratively elevated portion of the table lands of that county—and
guided by the same principle, in tracing a supposed connected chain
which forms the water-shed of both the east and west-discharging
rivers, the same title has been applied to a portion of the Blue Ridge,
constituting the western boundary of Patrick and Grayson counties.
Thus we have the same term applied successively to ridges entirely
dissimilar in regard to the materials of which they are composed,
and the epochs to which they are geologically to be referred; and
what is of much more practical importance, mistaken conceptions of
the nature and resources of these districts will be almost certainly
suggested, on a first view of them, as delineated upon the map,
from the prevailing idea, that a continuous mountain chain, thus
bearing a common designation along its entire extent, must of
course exhibit great similarity in structure and materials throughout
all its parts. Nor is this all: by following the fallacious guide of the
direction of the drainage, instead of actually tracing continuous
ridges, likely to present a general similarity in character throughout,
we are in many cases giving an imaginary continuity to elevated
portions of land frequently belonging to successive ridges, and thus
creating in imagination a connected mountain in a direction or
directions in which none such actually exists. Hence, nothing is
more common in descriptions than to hear of the Alleghany passing
under the Peter’s mountain, near the Sweet springs, traversing the
various ridges to the east until it arrives at Christiansburg, and
thence by many crooked courses, tending towards the Blue Ridge,
until reaching that mountain, it suddenly cuts it off, and bends its
own course to the south-west. But during all this description, the
speaker is seldom aware that he is describing what, to a great ex-
tent, has no original in nature, and that what he represents as one
mountain, a continuation of the great Alleghany of the upper and
middle portions of the state, here striking across the numerous
ridges to the east, and making in its way in that direction under and
over and through the numerous mountains which seem crowded in

15

114

a phalanx to résist its course, is, in reality, through much of its ex-
tent, only a series of spurs, sometimes merely elevated table lands,
dissimilar in structure and origin amongst each other, and only as-
sociated in an imaginary connexion by the accidental circumstance
that they form one portion of the water-shed of the east and west-
discharging rivers. A more accurate knowledge of the topography
of the state, and more judicious principles in the application of terms,
will, it is hoped, at some future day, correct this preposterous error
in the designation of our mountains, and will substitute on our map
such names as the real constitution of ridges of analogous formation
throughout, would render natural and appropriate. Thus the
western boundary of Patrick and Grayson ought to be called Blue
Ridge, and no ridge or mountain east of the Peter’s mountain can,
with the least propriety, be entitled Alleghany.

OF THE SOUTH-WESTERN DISTRICT OF THE STATE.

In exhibiting a few particulars relating to mineral structure and
resources of the south-west, we will confine our attention chiefly to
the limestone, lead, gypsum, salt and coal, which it possesses.

Much of this region is overspread with fossiliferous limestone of
various kinds, as well as other varieties containing no fossils, and
approaching in some places to the character of marble. Semi-bitu-
minous coal is found in several localities, as on Strouble’s run, &c.
in Montgomery, and in other places in the Brushy and Walker’s
mountain. Iron ore is also abundant in the same districts.

The lead ores of Wythe, under judicious management in the
working, and with favourable means of conveying the resulting
metal to the proper market, could not fail to become a large source
of profit to the state. In the forms of sulphuret and carbonate, they
contain a large per centage of the metal, and require no expensive
arrangements for the reduction, the sulphur in the one, and the car-
bonic acid in the other, readily escaping under the application of a
heat of moderate intensity. -Both of these ores are wrought, al-
though of late it would appear that the carbonate is preferred, on
account, it is said, of its yielding a lead of purer quality. The sul-
phuret, as is frequently the case, contains probably antimony or ar-
senic, perhaps both, while the carbonate is much more likely to
include no other, metallic ingredient but the lead. Until lately, the

a

115

ore of this description, from its earthy appearance in most cases
and its total want of an external metallic aspect, had been rejected
as of no value, and it was only by accident that its character was
revealed to those who were working in the mines.

The sulphuret or blue ore (galena,) occurs in veins of rotten or
chalky limestone ; the carbonate, in beds generally situated at the
intersection of the veins. In the extraction of the metal the fuel
employed is wood, and the operation is performed in a simple rever-
beratory furnace.

The gypsum, as far as certainly known, occurs over a space about
20 miles in length, and half a mile in breadth, but probably the area
actually occupied by it is much more considerable. The depth to
which it extends in some places is enormously great. It lies in beds
between strata of limestone, slate, and sometimes sandstone, and
has to be penetrated for a great depth in boring for salt water. In
some cases it is said to have a thickness of nearly 300 feet, including
the bands of rock among which it is stratified. Its condition is either
that of a fibrous crystalline mass of nearly perfect purity, or a granu-
lar bluish-gray and veined rock, containing a small amount of earth,
but still as little mingled with extraneous matter as any of the im-
ported plaister. This precious material, owing to the difficulty of
transportation, is yet unknown at any distance towards the sea-
board, but during favourable seasons it is conveyed in arks down
the Holston, to the south-western states, and in this way yields a
handsome profit. With facilities of transportation, what incalculable
benefits might the great valley of Virginia, and much of the region
west, as well as east of it, derive from this invaluable deposite, and
what an active and productive commerce might it give rise to
throughout that region in which it is found.

The salines constitute another of the treasures of this district of
he state. As yet but little has been done, either towards determin-
ng the extent of the saliferous strata, or the chemical nature of the
various ingredients, besides the common salt, which the brine holds
dissolved. At the salt-works on the Holston, the wells are usually
from two to three hundred feet in depth, presenting strata of lime-
stone near the surface, sandstone or slate alternating with beds of
gypsum several feet in thickness, next beneath, and finally, a stra-
tum of clay, within which the salt-water is procured. This clay is
of a reddish aspect, and a very argillaceous texture, being in all

116

probability a softened shale, such as that of the brine springs and
rock salt of Cheshire in England. In fact, a marked analogy is pre-
sented in the structure of the salt region of the Holston, and that of
Cheshire. In the latter, beds of gypsum are found alternating with
strata of indurated clays and sands, approaching to slates and sand-
stones ; and carbonate of lime exists largely in the strata lying near
the surface. In all these particulars the salt region of the Holston
corresponds with it very closely.

The great value of the Cheshire region, however, results from the
heavy beds of rock salt which it includes, and of the existence of
such upon the Holston, though far from improbable, no positive
testimony has as yet been obtained.

The curious fact, that on some occasions granules or small crys-
tals of salt, are brought up by the water of the wells, is certainly
very much in favour of the opinion, that such beds of the massive
salt do actually exist at depths to which the borings hitherto made
have not extended, and furnishes strong additional incentives to a
persevering and thorough exploration by borings in numerous places
penetrating to still greater. depths.

The proportion of common salt varies with different wells, and
even in the same is not perfectly uniform. In some cases 10 gal-
lons of the brine will yield one gallon of salt, in others 16 are neces-
sary. Taking the specific gravity of salt at about 2.5, and allowing
something for the interstices in the dry measure, we would have in
_ the former case a strength of about 20 per cent. Gypsum is always
present in the brine, and is almost the only impurity in it.

Of the coal occurring in Montgomery, and other parts of the S. W.
region, nothing at present need be added, as the remarks already
made in regard to the beds of the same variety of this mineral, oc-
curring in the Catawba mountain and elsewhere, would be equally
applicable to those found further south: Iron ore of a very peculiar
character is found in Grayson and Wythe, &c., yielding in some
cases by the usual smelting process, a metal having all the qualities
of steel. : °

The composition of this ore, now not known, would throw great
light on this interesting result, and might enable those engaged in
the iron works of the country, to secure a uniform production of
this more’ valuable form of metal, instead of being subject to the

117

capricious results of having cast iron at one time, and at another,
without any apparent reason, a superior quality of steel.

THE GREAT WESTERN BITUMINOUS COAL AND SALT REGION.

We come now to treat of that enormous area of nearly horizon-
tal strata which we have designated as the fifth great geological sub-
division of Virginia. It comprises as already shown, the large ter-
ritory lying between the western limits of the state and an irregular
line of mountain ranges as yet imperfectly determined, but nearly
coinciding with the eastern front ridge of the Alleghany, the Green-
brier mountains and the great Flat Top mountain. No section of
the whole state offers perhaps so much that is characteristic, either
in its physical geography or geological structure, and none holds
out richer promise of valuable practical results as soon as it shall be
systematically explored. By far the greatest portion, if not all, of
its strata, belong to a group of formations, distinguished not only
in America but through the world, as being the chief depositories of
bituminous coal. The title of the western carboniferous region
might therefore seem to be appropriately applicable to it, were we
sure that it might not.convey to geologists and others a possibly
erroneous conception of the class of rocks which it comprehends.
While it is clearly referable to the general period of the bituminous
coal, it is by no means meant to signify that the rocks of the region
correspond with any exactitude, or indeed have any mineralogical
analogy to the strata which comprise the bituminous coal formation
of most geological writers. Nor, on the other hand, is it settled,
that the era of their production was precisely the same during
which the coal beds of other countries were deposited. We hold
it to be altogether premature, while the geologists of America are
yet only on the threshold of their researches, to endeavour to esta-
blish an identity of names between our strata and those of Europe.
This too frequent error, prejudges all the broader and more lofty
generalizations of the science. In a spirit of caution, therefore,
dictated by the many blunders daily committed in the nomenclature
of our rocks, we shall abstain from giving them a class of European
names, not always indeed applicable in the countries where they are
employed, and certainly Jess so in a region of widely different struc-
ture, separated by the great interval of the Atlantic. The little that

118

can be said in a detailed way upon particular strata will be descrip-
tive, being convinced that points of nomenclature and classification
cannot be ventured upon with profit until there shall have been col-
lected a vast deal more minute information than is now before us.

This western section of Virginia is characterized throughout by
geographical features of great simplicity. The surface of the region
is undulating, and towards its south-eastern limit, mountainous ; but
the loftiest hills rise in gently swelling outlines, and no very promi-
nent peaks tower in acute and ragged lines, to denote that the strata
have been subjected to violent convulsive and upheaving forces.
Every thing bespeaks it to have been at one time an expanded
plain, gently tilted from the horizontal position, so that its surface
and the beds of rock beneath, decline with a slight but very uniform
depression, very generally towards the north-west to the valley of
the Ohio.

The form, direction and character of both hills and valleys, give
evidence that its inequalities of surface were caused by the furrowing
action ofa mighty and devastating rush of waters, which by a rapid
drainage scooped out enormous valleys and basins in the upper
strata, the remnants of which are consequently traceable across the
widest valleys from hill to hill, holding the same elevation, thickness
and inclination to the horizon. It is from this deep excavation of
the strata by natural causes, combined with the other important cir-
cumstances of a nearly horizontal position, that we are to draw our
estimate of the prodigious resources of a mineral kind possessed by
the region before us. Whatever valuable materials lie included in
the strata of the district, coal, salt, limestone or iron ore, the hori-
zontal position alluded to keeps them near the surface, or at an acces-
sible depth, over enormously wide spaces of country, while the
trough-like structure of the valleys, and their great depth, exposes
the edges of many of these deposites to the day, under positions in
which mining is the easiest imaginable, and with an extent of de-
velopement not less accommodating to the researches of the scien-
tific geologist than bountiful to the wants of the community. The
same features prevail in the tertiary or tide water district of the
state, and ought to awaken there a corresponding feeling of congra-
tulation. The only essential difference of structure, is the far greater
depths to which the beds of this western territory have been ex-
cavated or denuded. A greater number of strata are there laid

119

open, contributing to render the deep-seated beds of coal as acces-
sible as the superficial marls of the lower section of the state, and
thereby to preserve a beautiful balance in the resources of the two
respective regions.

The portion of the profile representing this vast and affluent divi-
sion of the state, along the particular line to which our observations
were chiefly directed, may be regarded as commencing with the
Meadow mountain, and extending as far as the Ohio; but by start-
ing from the point here indicated, it is by no means intended to
imply that the great western series of secondary rocks here actually
commence. So far as an inspection of the ground along the route
observed may be regarded as furnishing information upon this in-
teresting point, the probable beginning of this series is to be looked
for farther to the east, and in all likelihood, is placed on the western
bank of Howard’s creek, the only position in which an approach to
unconformable stratification was observed. As however we have
already described the limestones of the Lewisburg valley and the
other strata with which they are immediately associated, and as
moreover our chief object at present is the presenting some par-
ticulars relating to that portion of the great western series which is
first distinctly observed towards the summit of the Meadow moun-
tain, we shall waive all merely scientific inquiries with respect to the
precise boundary of the western rocks, and proceed briefly to de-
scribe the structure of this region westward from the point already
indicated.

Ascending {the Meadow mountain, we meet with blue and red
slate in a friable condition, until we arrive at a point more than half
way to the top, where gray sandstones make their appearance,
forming the cap of the mountain, and like the slates beneath, dipping
with a gentle inclination to the west; descending on the western
side the slates again appear, and continue throughout the whole of
the extensive flat reaching to the base of the Little Sewell, on the
eastern side of which they are soon lost, and a gray sandstone, like
that already remarked, again comes into view. The upper portion
of the Little Sewell consists of a gray and white sandstone, identical
with that observed in progressing further west. Here one or more
seams of coal have been discovered. On the western flank of this
mountain, the red slate is again observed dipping gently west be-
neath the other rocks, and here finally disappearing under the beds.

120

of sandstone accumulating in thickness in our progress west. Con-
tinuing in the same direction, a series of these sandstones of various
hues and different textures, including numerous seams of coal, and
all dipping as before, but with a diminishing inclination, so as in
fact to approach nearly to the horizontal, accompany us through the
Big Sewell, Davy’s mountain, Bracken’s Ridge, Dogwood Ridge,
Gauley mountain, &c., to a point west of Campbell’s creek, where
a gentle counter dip of the same rocks may be remarked, soon,
however, exchanged for the general direction before observed.
Here, as indicated in the profile, three great seams of coal display
themselves almost continuously for a distance of about 12 miles,
stretching in parallel and nearly horizontal bands along the almost
mountainous cliffs forming the boundaries of the rich and lovely
valley of the Kanawha in the vicinity of Charleston.

Beyond this point, the level of the country declining, we come
upon a series of nearly horizontal arenaceous and argillaceous rocks
occasionlly presenting thin beds of limestone of various degrees of
purity, in some cases containing sufficient alumina to render it
valuable for hydraulic lime. This portion of the series extends as
far as the banks of the Ohio.

The sandstones of which it will be seen so large a portion of this
region is composed, are remarkable for the enormous size of some
of the fossils which they contain, and the shales associated with the
coal are even still more rich in some places in these colossal relics
of a former world. A striking feature already alluded to in speak-
ing of the sandstones near the valley of Lewisburg, is observed very
generally throughout this region, and is exemplified in some of the
cliffs of the New river and Kanawha, on a scale of vast extent. I
mean the diagonal lamination of the rock—or, in other words, a
subordinate stratification oblique to the general lines of demarkation
of the several parallel beds of which the whole mass of the cliff or
mountain is composed. A similar fact was noticed in describing the
tertiary rock of broken shells at York, and the beds of gravel
observed in the neighbourhood of Richmond and at other places in
lower Virginia. In all these cases, a like agency has been at work
in producing this curious structure. In all of them we readily dis-
cover the action of tides or currents, depositing upon a surface,
originally, by some accidental cause, inclining to the horizon, the
sands and pebbles, and other materials of the rock, and thus adding

121

layer after layer of the deposited material in directions parallel to
the receiving surface, and therefore oblique to the general horizontal
level. Changing intensity or direction in the transporting tide or
current, would be accompanied by an alteration in the position or
direction of the lamina thus formed—and it is easy to perceive, that
an almost endless variety of structure in this respect might thus be
readily explained. The fact here noticed, furnishes of itself a strik-
ing evidence, were any such wanting, of the submarine origin of the
vast region of which we are nowtreating. But the organic remains
which these rocks entomb, at once demonstrate this to have been
the fact—the relics of marine animals being the only remains found
among the sandstones which are not immediately associated with
the coal.

With the view of illustrating the extent of mineral wealth of which
this region is possessed, and at the same time of indicating the vast
benefits which it may anticipate from a geological and chemical in-
vestigation of these resources, I will briefly refer to some of the
more important deposites as yet known, of its coal and iron ore and
salt.

At Wheeling, and for 14 miles down the river, the cliff or bank
presents an uninterrupted bed of highly bituminous coal, upwards
of 16 feet thick, and of such a quality, as to furnish fuel for all the
dwellings and manufactories of that enterprising and prosperous
town, Above and separated by other beds, are two thinner layers
of this material, but of an inferior value. Associated with these
seams of coal, and lying above the two lower ones, is a bed of lime-
stone of upwards of twenty feet in thickness.

At Clarksburg and northward down the valley of the Monon-
gahela, there exists one of the richest coal deposites in the state.
One of the seams in some places in the neighbourhood of this town,
is from 10 to 12 feet in thickness, below which, and separated
chiefly by a heavy bed of sandstone, there lies a thinner stratum
of a more highly bituminous character. These also are associated
with a layer of limestone. We may form some idea of the vast
extent of these coal seams from the fact, that from some distance
above Clarksburg, they may be followed with scarcely any inter-
ruptions throughout the whole length of the valley of the Mononga-
hela down to Pittsburg. Ascending the Tygart’s valley river, the
coal diminishes in thickness and valuable qualities, while the sand-

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122

stones and limestones increase, the latter in the Cheat and other
mountains, near the sources of the river, having a thickness of
from 60 to 100 feet.

Coal is also found, though in less considerable seams, along the
valley of the Little Kanawha. Near Hughes’ river, one of its
tributaries, it is very abundant; and in the same neighbourhood,
springs of petroleum, or rock oil, have been discovered. North and
west of this stream on the ridge, selenite or crystallized gypsum is
said to occur, though at what place and to what extent, we are not
informed.

On the Great Kanawha, the exposure of coal is one of the most
extensive and valuable anywhere in the United States, and here
from its immediate vicinity to the Salines, its practical usefulness
has been tested on a wide and profitable scale. On the Coal,
Gauley, and other rivers in this portion of the west, the beds of
this mineral are frequently brought to view, and in fact no better
general description can be presented of its extent, than that it is al-
most continuous with the vast beds of sandstone, which spread in
nearly horizontal planes over nearly the whole of this broad
region.

A coal containing much less bituminous matter, occurs immedi-
ately west of the eastern front ridge of the Alleghany, in Hampshire
county, lying in nearly horizontal beds; in-five successive tiers, and
extending for a distance of many miles along the borders of the
Potomac. A simple enumeration of the strata here exposed, will
furnish an illustration of the resources of this corner of the state,
well calculated to inspire astonishment ~and exultation. Upon a
stratum of valuable iron ore, not less than fifteen feet in thickness,
there rests a bed of sandstone, upon which reposes a coal seam,
three feet thick ; above this, another bed of sandstone, then a two
feet vein of coal, next sandstone, then another coal seam of four feet;
again a stratum of sandstone, and over it a seven feet vein of
coal; over this, a heavy bed of iron ore, and crowning the series,
an enormous coal seam of from fifteen to twenty feet in thickness.

The Saline formation, associated with the vast strata of sandstone
before described, has as yet been almost unexplored, excepting in
the valleys of the Great and Little Kanawha. High up, on the
New River, and at one or two points on the Greenbrier, salt water
has been found, and the erection of salt works has been attempted,

123

though hitherto these efforts have proved unsuccessful, either on
account of the weakness or the insufficient supply of the brine.
What may be the result of future research in the region east of
that in which the salt manufacture is now successfully pursued, it
would be impossible to predict, but from the fact, that the rocks of
all this region, and among them the white sandstone from which the
brine of Kanawha is procured, have a gentle western dip, it would
appear reasonable to infer, that in the range of the Sewell mountains,
and some distance east, where these rocks, which at the Salines are
many hundred feet deep are brought nearly to the surface, the sup-
ply of salt water might in some places be obtained ata comparatively
inconsiderable depth, and at all events, considering the continuity
and identity of the strata over the whole of this wide area, we may
reasonably suppose, that the saliferous bed or beds would be found
in nearly every portion of it, though perhaps in many places having
too slight an impregnation to render the water yielded, of any value
in the manufacture of salt.

On the Great Kanawha, wells of various depths, rarely exceed-
ing 400 feet, have been sunk on both sides of the river above
Charleston, throughout a distance of more than twelve miles.
The brine thus procured, unlike most other salt waters, contains
scarcely any sulphate of lime or gypsum, -on which account the
process of obtaining the salt in a pure crystalline condition, is at-
tended with fewer difficulties than usual; and for this reason, the
alum salt now procured by the improved methods of operating
recently introduced, may be regarded as muriate of soda, in almost
absolute chemical purity. The importance and value of the Salines
in this vicinity, may be inferred from the fact, that about three
millions of bushels of salt are now annually made from them, and
that in the manufacture of this article alone, more than twice the
quantity of coal is consumed every year than is furnished by all
the coal mines of eastern Virginia put together. This coal being
procured from the hills adjacent to the salt furnaces, is obtained at
comparatively little cost: presenting an example of the fortunate
adaptation of the resources of a region to each other, of which few
equally remarkable are to be met with any*where in the world. En-
terprise incited by so happy a combination of advantages could not
fail of bestowing prosperity upon a region which is thus blessed, and
we, therefore, find throughout the whole extent of the valley, where

124

the salt manufacture is pursued, and even over a wide extent of
country, connected indirectly with its operations, a degree of
activity and industry and wealth, which we would in vain look
for in our rural districts generally, and which, when first beheld after
quitting the wild and almost uninhabited regions by which the travel-
ler from the east approaches the Kanawha, cannot fail to kindle in
his mind a vivid sentiment of pride, astonishment and pleasure.

A general structure in all respects analogous to that presented
in the portion of the profile last described, pervades the whole of
that vast area of which the boundaries have been approximately
stated in the beginning of this division of the report. But with
features of strong general resemblance, it must not be imagined that
local peculiarities do not exist in the different portions of this region,
developing not only many objects of geological and curious interest,
but also bringing to light many of the mineral treasures of which
this favoured territory is possessed. There is no point of view,
however, in which the immeasurable riches of this region are ren-
dered more obvious to our minds, than that of the uniform and
continuous structure which has already been described. For, it is
in these widely spreading strata of sandstone, that nearly all the
boundless treasures of this country are enclosed, and the continuous
character exhibited by them, gives the strongest possible assurance
of a like uninterrupted extension of the various beds of valuable
materials which they include. In this view, how magnificent is
the picture of the resources of this region, and how exhilirating the
contemplation of all the happy influences upon the enterprise, wealth,
and intellectual improvement of its inhabitants, which are rapidly
to follow the successive developement of its inexhaustible mineral
possessions. In a country where the channels of nearly all the prin-
cipal rivers have been scooped out in part through beds of coal,
where some of them are paved with the richest ores of iron, and
where the very rock itself, the sterile sandstone of the cliffs and
mountains, is enriched at certain depths with abundant stores of
salt, what more is needed to fulfil the happy and glorious destinies
that await it, than to awaken enterprise to a due appreciation of the
golden promises it holds out, and to direct industrious and active
research to the thorough investigation of the character, position,
and uses of the treasures it contains!

125

Note on the fertilizing efficacy of Greensand, extracted from the re-
port on the Geology of New Jersey, by Professor H. D. Rogers;

“Mr. Woolley, of Poplar swamp, Monmouth county, N. J.,
manured a piece of land in the proportion of 200 loads of good
stable manure to the acre, applying upon an adjacent tract of the
same soil, his marl, in the ratio of about 20 loads per acre. The
crops, which were timothy and clover, were much the heaviest
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 enriched by it was entirely clear of
weeds, while the stable manure had rendered its own crop extremely
foul.

“There can be no doubt that 20 loads of marl per acre must be
regarded as an unnecessarily bountiful dressing, but computing the
relative cost of the two manures when employed in the ratio above
stated, we find a considerable disparity of expense in favour of the
greensand. Placing the home value of farm-yard manure at 100
cents for each two horse load, and that of the marl at 25 cents
per load, we have the expense of manuring one acre 20 dollars, of
marling the same 5 dollars.

«Experience has already shown that land once amply marled,
retains its fertility with little diminution for at least 10 or 12 years,
if care be taken not to crop it too severely; while with all practi-
cable precautions, the stable manure must be renewed at least three

times within that interval, to maintain in the soil a corresponding
vigour.”

126

PROPOSED PLAN OF THE GEOLOGICAL SURVEY.

The survey should aim at three principal results, each of which is
essential to a proper developement of the native mineral resources of
the state :

First, the production of a report descriptive of the minute geology,
practical and scientific, of all parts of the state.

Second, the construction of a geological map and a series of ac-
companying sections or profiles, both necessary to a proper exhibi-
tion of the geology of the region, and capable of conveying a fund of
useful information, which no mere report can.

Third, the formation of a cabinet designed to exhibit the mineral
materials described in the report, and represented on the map and
sections.

As a mere description of the geology of a country, if unaccompa-
nied by a map and sections, can convey only a very imperfect idea
of the structure and relations of its formations, it becomes necessary
to have the geographical map as accurate as possible, inasmuch as
errors in this will vitiate more or less the geology. The proper
basis on which to lay down a geological survey, is a minute topo-
graphical map, the production, however, of which at the present time,
would be too tardy and too costly. The existing state map being
very inaccurate in various points, which, if retained in the geological
map, might lead to serious practical mistakes, one duty of this sur-
vey should be to rectify such portions of the topography as must be
corrected previous to laying down the geology. This implies a cer-
tain amount of topographical duty, which it is designed to perform
only when rendered necessary by the demands of the geological
survey.

To the topographical branch of the survey might be attached two
or three extra duties, some of which would greatly promote the
strictly geological part of the survey, and in like manner augment
largely our stock of useful information upon the internal resources
of the state. One should be to procure numerous barometrical ob-
servations of the heights of our mountains, more especially the gorges
and passes over which roads may from time to time be carried. An-
other ought to embrace a set of observations on the drainage or wa-
ter power of the several hydrographic sections of the state. This

— ee
RR a aaa

en Eee et maaan —_— same

ISS OED AN ce
.

127

would act usefully in all suggestions for canals, and also tend to the
developement of manufacturing enterprise.

A general plan only can be given, according to which, it would be
most eligible to enter upon the geological researches, for the move-
ments of those engaged in the survey must be shaped to a conside-
rable extent by the geological relations of the several districts of the
state as they are brought to light. It is deemed proper that the first
seasons be taken up in part in a general exploration of all the prin-
cipal regions of the state, and in part in a detailed investigation in a
systematic order of each class of formations. In this way a multi-
tude of valuable facts easily reached, will be brought to light by the
earliest possible day, and the regular execution of the state map will
be in progress from the commencement of the survey, and its ulti-
mate completion greatly expedited.

It is proposed to connect with these general examinations, a mass
of chemical investigations, intended to be of immediate application
in the employment of the materials brought under review; also, to
render annual reports upon such points of the survey as are more
pressingly wanted, and which are capable of being completed in a
single season, reserving the minute and comprehensive description
of the whole geology of the state for a general final report. These
annual and specific reports can be accompanied by sections across
the strata, the execution of which is compatible with much less time
than is essential to the construction of the geological map. In this
way much definite knowledge can be disseminated without waiting
for the final completion of the enterprise, and the map will be greatly
benefited by the investigations auxiliary to these profiles.

The facts, and general views of the geological structure of the
state, brought to light in the re¢onnoissance, enable one to suggest
nearly the directions most proper for the principal sections or pro-
files across the formations of the state.

It is proposed to make one lie between the Potomac somewhere
near Alexandria and the Alleghany mountain near Cumberland ; an-
other from the Atlantic across the Eastern shore and the Chesapeake
bay, at a point between the Potomac and Rappahannock rivers, to
reach to the Ohio river near Fishing creek; a third to stretch from
‘the Chesapeake bay between the York and James rivers to the Ohio
near the mouth of the Little Kanawha; a fourth to commence at the
North Carolina line between the Chowan and Roanoke rivers, and

re,

128

to follow the general line of the Great Kanawha to the Ohio; a fifth
to stretch from the North Carolina line, at some eligible point in Pa-
trick county, and to meet the former section at the mouth of the New
river; a sixth to reach from the same state line, some where in Gray-
son county, to the valley of the Guyandotte river, and to pursue the
general direction of this to the Ohio.

The detailed location of these six great lines will be made to de-
pend, in great measure, on local features, and the exigencies arising
out of the peculiar geology and geography of each belt of country to
be traversed. Their positions have been chosen with a view to in-
tersect the greatest number of strata practicable, and in the most ad-
vantageous directions for exposing the formation of every geological
subdivision of the state. All the principal ridges are crossed nearly
at right angles, and an eye has been had to the greater facilities for
investigation afforded by the valleys of the large rivers.

As before said, the survey of the zones of country lying along the
sections, makes but a portion, and rather the preliminary portion, of
the whole survey. In the construction of the map, and the detailed
examinations of the systematic survey, the wide tracts of country
included between these profiles, would require to be minutely tra-
versed, especially in the longitudinal direction of the strata, to ascer-
tain and depict their boundaries.

A correct knowledge of any region, sufficiently thorough for prac-
tical purposes, can only be attained by running from one formation
to the neighbouring ones, crossing their boundaries repeatedly in a
zigzag course, SO as ultimately to cover the whole surface with a net
work of lines more or less close, according to the degree of intricacy
in the geology of each district; influenced too by the value of the
mineral contents of the strata.

It is proposed that the state cabinet, which is to grow out of the
survey, should be deposited in a suitable apartment in the capitol,
accessible to any citizen of the state, seeking the valuable local and
specific information which can only be derived from a collection of

specimens.
It is contemplated to commence the formation of the cabinet forth-

_ with; that is to say, to accompany each annual report with a suite
of specimens illustrative of it—to be grouped according to the most
natural order in the mean while, and ultimately to receive a thorough
systematic classification.

129

The specimens ought to consist of the characteristic rocks of each
formation, arranged as nearly in the order which they observe in
nature as practicable; also the minerals, ores, marls, peculiar soils,
organic remains, and other objects to which reference may be desi-
rable by those engaged in agriculture and the arts, or by those who
may study the mineral productions of the state, for less specific pur-
poses.

As it is proposed to make a chemical investigation of the compo-
sition of these materials an essential feature of the plan, the analyses
given in the reports will be annexed to the specimens examined,
that thus every one consulting the cabinet may know at the same
time the external aspect, and the composition of a substance, capable
of useful applications. The analyses essential to this, not the least
useful part of the survey, from the arduous nature of the task, will
be confined to substances of more immediate interest and utility.

17

GLOSSARY
OF GEOLOGICAL AND OTHER SCIENTIFIC TERMS.

FROM LYELL’S PRINCIPLES OF GEOLOGY,

Alluvium. Earth, sand, gravel, stones, and other transported matter
which has been washed away and thrown down by rivers,
floods, or other causes, upon land not permanently submerged
beneath the waters of lakes or seas. Etym., alluo, to wash
upon. ii

‘Amorphous. Bodies devoid of regular form. Etym., a, a, without,
and open, morphe, form.

Amygdaloid. One of the forms of the Trap-rocks, in which agates
and simple minerals appear to be scattered like almonds in a
cake. Etym., ayvydara, amygdala, an almond.

Analcime. A simple mineral of the Zeolite family also called Cu-
bizite, of frequent occurrence in the trap-rocks.

Anticlinal Avis. If a range of hills, or a valley, be composed of
strata, which on the two sides dip in opposite directions, the
imaginary line that lies between them, towards which the
strata on each side rise, is called the anticlinal axis. Ina
row of houses with steep roofs facing the south, the slates
represent inclined strata dipping north and south, and the ridge
is an east and west anticlinal axis.

Arenaceous. Sandy. Etym., arena, sand.

Argillaceous. Clayey, composed of clay. Etym., argilla, clay.
Arragonite. A simple mineral, a variety of carbonate of lime, so
called from having been first found in Arragon, in Spain.
Augite. A simple mineral of a dark green or black colour, which

forms a constituent part of many varieties of volcanic rocks.

Basalt. One of the most common varieties of the Trap-rocks. It
isa dark green or black stone, composed of augite and felspar,
very compact in texture, and of considerable hardness, often
found in regular pillars of three or more sides, called basaltic

are eemnerneneee slat) serena

13]

columns. Remarkable examples of this kind are seen at the
Giant’s Causeway, in Ireland, and at Fingal’s Cave, in Staffa,
one of the Hebrides. The term is used by Pliny, and is said
to come from basal, an Aithiopian word signifying iron. The
rock often contains much iron.

“ Basin” of Paris, “ Basin” of London. Deposites lying in a hollow
or trough, formed of older rocks, sometimes used in geology
almost synonymously with “ formations” to express the depo-
sites lying in a certain cavity or depression in older rocks.

Belemnite. An extinct genus of the order of molluscuous animals
called Cephalopoda, having a long, straight, and chambered
conical shell. Etym., Ssasuvov belemnon, a dart.

Bitumen. Mineral pitch, of which the tar-like substance which is
often seen to ooze out of the Newcastle coal when on the fire,
and which makes it cake, is a good example. Lfym., bitumen,
pitch.

Bituminous Shale. An argillaceous shale, much impregnated with
bitumen, which is very common in the coal measures.

Blende. A metallic ore, a compound of the metallic zine with
sulphur. It is often found in brown shining crystals, hence
its name among the German miners, from the word dblenden, to
dazzle.

Botryoidal. Resembling a bunch of grapes, Ltym., Borpus, botrys,
a bunch of grapes, and sidog eidos, form.

Bowlders. A provincial term for large rounded blocks of stone
lying on the surface of the ground, or sometimes imbedded
in loose soil, different in composition from the rocks in their
vicinity, and which have been therefore transported from a
distance,

Breccia. A rock composed of angular fragments connected together
by lime or other mineral substance. An Italian term.

Calc Sinter. A German name for the deposites from springs hold-
ing carbonate of lime in solution—petrifying springs. L£tym.,
kalk, lime, sintern, to drop.

Calcareous Rock. Limestone. Ltym., calx, lime.

Calcareous Spar. Crystallized carbonate of lime.

Calcedony. A silicious simple mineral, wncrystallized. Agates are
partly composed of caleedony.

132

Carbon. An undecomposed inflammable substance, one of the
simple elementary bodies. Charcoal is almost entirely com-
posed of it. Etym., carbo, coal.

Carbonate of Lime. Lime combines with great avidity with car-
bonic acid, a gaseous acid only obtained fluid when united
with water,—and all combinations of it with other substances
are called Carbonates. All limestones are carbonates of lime,
and quick lime is obtained by driving off the carbonic acid by
heat.

Carbonic Acid Gas. A natural gas which often issues from the
ground, especially in volcanic countries. Etym., carbo, coal,
because the gas is obtaingd by the slow burning of charcoal.

Carboniferous. A term usually applied, in a technical sense, to an
ancient group of secondary strata, but any bed containing coal
may be said to be carboniferous. Ltym., carbo, coal, and fero,
to bear.

Cephalopoda. A class of molluscous animals, having their organs
of motion arranged round their head. Etym., xepara, cephale, a
head, and soda, poda, feet.

Cetacea. An order of vertebrated mammiferous animals inhabiting
the sea. The whale, dolphin, and narwal, are examples.
Etym., cete, whale. a

Chalk. A white earthy limestone, the uppermost of the secondary
series of strata.

Chert. A silicious mineral, nearly allied to caleedony and flint,
but less homogeneous and_ simple in texture. A gradual pas-
sage from chert to limestone is not uncommon.

Chloritic Sand. Sand coloured green by an admixture of the simple
mineral chlorite. Ltym., xAwpos, chloros, green.

Clinkstone, called also phonolite, a felspathic rock of the Trap
family, usually fissile. It is sonorous when struck with a
hammer, whence its name.

Coal Formation. This term is generally understood to mean the
same as the Coal Measures. There are, however, *‘ coal for-
mations” in all the geological periods, wherever any of the
varieties of coal form a principal constituent part of a group of
strata.

Conformable. When the planes of one set of strata are generally

133

parallel to those of another set which are in contact, they are
said to be conformable.

Conglomerate or Puddingstone. Rounded water-worn fragments
of rock or pebbles, cemented together by another mineral sub-
stance, which may be of a silicious, calcareous, or argillaceous
nature. Ztym., con, together, glomero, to heap.

Coniferx. An order of plants which, like the fir and pine, bear
cones or tops in which the seeds are contained. L£tym.,
conus, cone, and fero, to bear.

Crag. A provincial name in Norfolk and Suffolk for a deposite,
usually of gravel, belonging to the Older Pliocene period.

Cretaceous. Belonging to chalk. tym., creta, chalk.

Crop Out. A woiner’s or mineral surveyor’s term, to express the
rising up or exposure at the surface of a stratum or series of
strata.

Crustacea. Animals having a shelly coating or crust which they
cast periodically. Crabs, shrimps, and lobsters are examples.

Cryptogamic. A name applied to a class of plants, such as ferns,
mosses, sea-weeds, and fungi, in which the fructification or
organs of reproduction are concealed. Ltym., xpumsos, kryptos,
concealed, and yapos, gamos, marriage.

Crystalline. The internal texture which regular crystals exhibit
when broken, or a confused assemblage of ill-defined crystals.
Loaf-sugar and statuary-marble have a crystalline texture.
Sugar-candy and calcareous spar are crystallized.

Debacle. A great rush of waters, which, breaking down all op-
posing barriers, carries forward the broken fragments of rocks,
and spreads them in its course. Z£fym., débacler, French, to
unbar, to break up as a river does at the cessation of a long
continued frost.

Delta. When a great river, before it enters the sea, divides into
separate streams, they often diverge and form two sides of a
triangle, the sea being the base. The land included by the
three lines, and which is invariably alluvial, was first called, in
the case of the Nile, a delta from its resemblance to the letter of
the Greek alphabet which goes by that name, A. Geologists
apply the term to alluvial land formed by a river at its mouth,
without reference to its precise shape.

134

Denudation. The carrying away by the action of running water
of a portion of the solid materials of the land, by which in-
ferior rocks are laid bare. Etym., denudo, to lay bare.

Dikes. When a mass of the unstratified or igneous rocks, such as
granite, trap, and lava, appears as if injected intoa great rent
in the stratified rocks, cutting across the strata, it forms a
dike; and as they are sometimes seen running along the
ground, and projecting, like a wall, from the softer strata on
both sides of them having wasted away, they are called in the
north of England and in Scotland dikes, the provincial name
for wall. It is not easy to draw the line between dikes and
veins. The former are generally of larger dimensions, and
have their sides parallel for considerable distances ; while veins
have generally many ramifications, and these often “thin-away
into slender threads.

Diluvium. Those accumulations of gravel and loose materials
which, by some geologists, are said to have been produced by
the action of a diluvian wave or deluge sweeping over the sur-
face of the earth. LEtym., diluvium, deluge.

Dip. When a stratum does not lie horizontally, but is inclined, the
point of the compass towards which it sinks is called the dip
of the stratum, and the angle it makes with the horizon is called
the angle or dip of inclination.

Dolerite. One of the varieties of the trap-rocks, composed of augite
and felspar.

Dolomite. A crystalline limestone, containing magnesia as a con-
stituent part. Named after the French geologist Dolomieu.
Dunes. Low hills of blown sand that skirt the shores of Holland,

England, Spain, and other countries.

Eocene. The great tertiary era is divided into four periods, the first
of which is called Locene, Ews, aurora, and Kaos, recent, indi-
cating that in the beds of this division, we see the first traces
or dawn of the present order of things. The class of fossils
most serviceable in determining the relations of the existing to
the extinct species, are shells, and it is between these, more
particularly that the comparison has been made. Out of about
1200 shells discovered in Europe in this lower division of the
tertiary rocks, 38 only are identical with species known to be

;

135

living. This small proportion (about 3 per cent.,) varies a
little, of course, with the deposites of different regions ; and the
deposites of this formation, like those of any other are charac-
terised less by the precise proportion of their extinct fossils,
than by possessing a number of shells peculiar to the particular
era, and found in no other tertiary groups.

Estuaries. Inlets of the land, which are entered both by rivers and
the tides of the sea. Thus we have the estuaries of the Thames,
Severn, Tay, &c. Htym. exstus, the tide.

Fault, in the language of Miners, is the sudden interruption of the
continuity of strata in the same plane, accompanied by a crack
or fissure varying in width from a mere line to several feet,
which is generally filled with broken stone, clay, &c.

felspar. A simple mineral, which, next to quartz, constitutes the
chief material of rocks. The white angular portions in granite
are felspar,

Ferruginous. Anything containing iron. £tym., ferrum iron.

Formation. A group, whether of alluvial deposites, sedimentary
strata, or igneous rocks, referred to a common origin or period.

fossil. All minerals used to be called fossils, but geologists now
use the word only to express the remains of animals and plants
found buried in the earth. Etym., fossilis, anything that may
be dug out of the earth.

Galena, a metallic ore, a compound of lead and sulphur. It has
often the high appearance of highly polished lead. E£tym.,
yarsu, galeo, to shine.

Garnet. A simple mineral generally of a deep red colour, crystal-
lized, most commonly met with in mica slate, but also in granite
and other igneous rocks.

Gault. A provincial name in the east of England for a series of
beds of clay and marl, the geological position of which is be-
tween the upper and lower greensand.

Gneiss. A stratified primary rock, composed of the same materials
as granite, but having usually a larger proportion of mica, and
a laminated texture. The word is a German miner’s term.

Granite. An unstratified or igneous rock, generally found inferior
to or associated with the oldest of the stratified rocks, and

136

sometimes penetrating them in the form of dikes and veins. It
is usually composed of three simple minerals, felspar, quartz,
and mica, and derives its name from having a coarse granular
structure; granum, Latin for grain.

Graywacke. Grawwacke, a German name, generally adopted by
geologists for the lowest members of the secondary strata.
The rock is very often of a gray colour, hence the name,
grau, being German for gray, and wacke being a provincial
miner’s term.

Greensand. Beds of sand, sandstone, limestone, belonging to the
Cretaceous period. The name is given to these beds because
they often, but not always, contain an abundance of green
earth or chlorite scattered through the anlage of the sand-
stone, limestone, &c. ;

Greenstone, a variety of trap, composed of hornblende and felspare

Grit, a provincial name for a coarse-grained sandstone.

Gypsum, a mineral composed of lime and sulphuric acid, hence
called also sulphate of lime. Plaster and stucco are obtained
by exposing gypsum toa strong heat. It is found so abun-
dantly near Paris, that Paris plaster is a common term in this
country for the white powder of which casts are made. The
term is used by Pliny for a stone used for the same purposes by
the ancients. The derivation is unknown.

Hornblende, a simple mineral of a dark green or black colour, which
enters largely into the composition of several varieties of the
trap rocks.

Hornstone. A silicious mineral substance sometimes approaching
nearly to flint, or common quartz. It has a conchoidal frac-
ture, and is infusible, which distinguishes it from compact
felspar.

Jura Limestone. ‘The limestones belonging to the oolitic group,
constitute the chief part of the mountains of the Jura, between
France and Switzerland, and hence the geologists of the Con-
tinent have given the name to the group.

Lamine. Latin for plates; used in geology, for the smaller layers
of which a stratum is frequently composed.
Lava. The stone which flows in a melted state from a volcano.

137

Lias. A provincial name, adopted in scientific language, for a
particular kind of limestone, which, being characterised together
with its associated beds, by peculiar fossils, forms a particular
group of the secondary strata.

Lignite. Wood converted into a kind of coal. Etym., lignum,
wood.

Lithological. A term expressing the stony structure or character
ofa mineral mass. We speak of the lithological character of
a stratum as distinguished from its zoological character. Etym.,
bos, lithos, stone, and doyos, logos, discourse.

Littoral. Belonging to the shore Etym., littus, the shore.

Loam. A mixture of sand and clay.

Madrepore. A genus of corals, but generally applied to all the
corals distinguished by superficial star-shaped cavities. There
are several fossil species.

Mammillary. A surface which is studded over with rounded pro-
jections. Etym., mammilla, a little breast or pap.

Mammoth. An extinct species of the elephant (Z. primigenius,)
of which the fossil‘bones are frequently met with in various
countries. The name is of Tartar origin, and is used in Siberia
for animals that burrow under ground.

Marl. A mixture of clay and lime; usually soft, but sometimes
hard, in which case it is called indurated marl.

Mastodon. A genus of fossil extinct quadrupeds allied to the
elephant. So called from the form of the hind teeth or grinders,
which have their surface covered with conical mammillary
crests. Etym., wacros, mastos, pap, and odw», odon, tooth.

Matrix. Ifa simple mineral or shell, in place of being detached,
be still fixed in a portion of rock, it is said to be in its matrix.
Matrix, womb.

Mechanical Origin, Rocks of. Rocks composed of sand, pebbles,
or fragments, are so called, to distinguish them from those of a
uniform crystalline texture, which are of chemical origin.

Mica. <A simple mineral, having a shining silvery surface, and
capable of being split into very thin elastic leaves or scales.
It is often called falc in common life, but mineralogists apply
the term tale to a different mineral. The brilliant scales in
granite are mica. Etym., mico, to shine.

18

138

Mica-Slate, Mica-Schist, Micaceous Schistus. One of the lowest
of the stratified rocks, belonging to the hypogene or primary
class, which is characterised by being composed of a large pro-
portion of mica, united with quartz.

Miocene. This is the period next succeeding the eocene, and em-
braces a larger share of recent or living species among the or-
ganic remains. It is called miocene from pciwy, less, and xatvos,
recent, implying that the formations in question contain less
recent than extinct species; or in other words, that the living
races are a minority. Out of 1021 shells in Europe, 176 only
belong to animals now living, making the proportion of the re-
cent species about 18 per cent.

Mollusca, Molluscous Animals. Animals, such as shell-fish, which,
being devoid of bones, have soft bodies. Etym., mollis;soft.

Mountain Limestone. A series of limestone strata, of which the geo-
logical position is immediately below the coal-measures, and
with which they also sometimes alternate.

Muriate of Soda. The scientific name for common culinary salt be-
cause it is composed of muriatic acid and the alkali soda.

New Red Sandstone. A series of sandy, argillaceous, and often cal-
careous strata, the predominant colour of which is brick-red, but
containing portions which are of a greenish-gray. These occur
often in spots and stripes, so that the series has sometimes been
called the variegated sandstone. The European formation so
called lies in a geological position immediately above the coal-
measures.

Nodule. A rounded irregular-shaped lump or mass. Etym., dimi-
nutive of nodus, knot.

Old Red Sandstone. A stratified rock belonging to the Carbonife-
rous group (of Europe.)

Oolite, Oolitic. A limestone, so named because it is composed of
rounded particles, like the roe or eggs of a fish. The name is
also applied to a large group of strata, characterised by peculiar
fossils, because limestone of this kind occurs in this group in
England, France, &c. Etym., wov, oon, egg, and Aides, Lithos,
stone.

Organic Remains. The remains of animals and plants (organized
bodies) found in a fossil state.

Orthocerata, or Orthocerx. An extinct genus of the order of Mollus-
cous animals, called Cephalopoda, that inhabited a long cham-

139

bered conical shell, like a straight horn. Ltym., opios, orthos,
straight, and xepas, ceras, horn.

Outliers. When a portion of a stratum occurs at some distance, de-
tached from the general mass of the formation to which it be-
longs, some practical mineral suryeyors call it an outlier, and
the term is adopted in geological language,

Oxide. The combination of a metal with oxygen; rust is oxide
of iron.

Oxygen. One of the constituent parts of the air of the atmosphere ;
that part which supports life. For a further explanation of the
word, consult elementary works on chemistry.

Pelagian, Pelagic. Belonging to the deep sea. Etym., pelagus,
sea.

Petroleum. A liquid mineral pitch, so called because it is seen to
ooze like oil out of the rock. Etym., petra, rock, and oleum,
oil.

Pisolite. A stone possessing a structure like an agglutination of
peas. LEtym., xidov, pison, pea, and Ardos, lithos, stone.

Pit Coal. Ordinary coal; called so because it is obtained by sink-

_ ing pits in the ground.

Pitch Stone. A rock of a uniform texture, belonging to the unstra-
tified and volcanic classes, which has an unctuous appearance
like indurated pitch.

Pliocene. This is derived from vAsiwy, more, and xaswos, recent, and is
founded upon the existence, in the beds which it embraces, of
a greater number of recent than extinct species. The pliocene
rocks are referred to two periods, the Older Pliocene and Newer
Pliocene; In the newer pliocene, the number of extinct species
is extremely small.

Plutonic Rocks. Granite, porphyry, and other igneous rocks, sup-
posed to have consolidated from a melted state at a great depth
from the surface.

Porphyry. An unstratified or igneous rock. The term is as old as
the time of Pliny, and was applied to a red rock with small an-
gular white bodies diffused through it, which are crystallized
felspar, brought from Egypt. The term is hence applied to
every species of unstratified rock in which detached crystals of
felspar are diffused through a base of other mineral composition

Etym., xoppupa, porphyra, purple.

140

Precipitate, Substances which having been dissolved in a fluid, are
separated from it by combining chemically and forming a solid
which falls to the bottom of the fluid. This process is the op-
posite to that of chemical solution.

Producta. An extinct genus of fossil bivalve shells, occurring only
in the older secondary rocks. It is closely allied to the living
genus Terebratula.

Pyrites. (Iron.) A compound of sulphur and iron, found usually in
yellow shining crystals like brass, and in almost every rock
stratified and unstratified. The shining metallic bodies, so
often seen in common roofing slate, are a familiar example of
the mineral. The word is Greek, and comes from zvp, pyr,
fire, because, under particular circumstances, the stone pro-
duces spontaneous heat and even inflammation. Pin

Quartz. A German provincial term, universally adopted in scientific
language, for a simple mineral composed of pure silex, or earth
of flints: rock-crystal is an example.

Sandstone. Any stone which is composed of an agglutination of
grains of sand, whether calcareous, silicious, or of any other
mineral nature.

Saurian. Any animal belonging to the lizard tribe. tym. caupa,
saura, a lizard.

Schist. Synonymous with slate. tym., Schistus, adj. Latin; that
which may be split, from the facility with which slaty rocks may
be split into thin plates.

Seams. Thin layers which separate two strata of greater magni-
tude.

Secondary Strata. An extensive series of the stratified rocks which
compose the crust of the globe, with certain characters in com-
mon, which distinguish them from another series below them,
called primary, and from a third series above sin called fer-
tiary.

Sedimentary Rocks, are those which have been formed by their ma-
terials having been thrown down from a state of suspension or
solution in water.

Selenite. Crystallized gypsum, or sulphate of lime—a simple mine-
ral.

Serpentine. A rock usually containing much magnesian earth, for
the most part unstratified, but sometimes appearing to be an

141

altered or metamorphic stratified rock. Its name is derived
from frequently presenting contrasts of colour, like the skin_of
some serpents.

Shale. A provincial term, adopted by geologists, to express an indu-
rated slaty clay. Etym., German schalen, to peel, to split.
Shell Marl. A deposite of clay, peat, and other substances mixed

with shells, which collects at the bottom of Jakes.

Shingle. The loose and completely water-worn gravel on the sea-
shore.

Silex. The name of one of the pure earths, being the Latin word for
flint, which is wholly composed of that earth. French geolo-
gists have applied it as a generic name for all minerals com-
posed entirely of that earth, of which there are many of dif
ferent external forms.

Silicious. Of or belonging to the earth of flint. £tym., silex,
which see. A silicious rock is one mainly composed of
silex.

Silt. 'The more comminuted sand, clay, and earth, which is trans-
ported by running water. It is often accumulated by currents
in banks. Thus the mouth of a river is silted up when its
entrance into the sea is impeded by such accumulation of
loose materials.

Simple Mineral. Individual mineral substances, as distinguished
from the rocks, which last are usually an aggregation of simple
minerals. They are not simple in regard to their nature, for,
when subjected to chemical analysis, they are found to consist
of a variety of different substances. Pyrites isa simple mineral
in the sense we use the term, but it is a chemical compound
of sulphur and iron.

Stalactite. When water holding lime in solution deposites it as it

- drops from the roof of a cavern, long rods of stone hang
down like icicles, and these are called stalactites. Etym.,
drarafw, stalazo, to drop.

Stalagmite. When water holding lime in solution drops on the
floor of a cavern, the water evaporating leaves a crust com-
posed of layers of limestone: such a crust is called stalagmite,
from ¢rakwyya, stalagma, a drop, in opposition to stalactite,
which see.

142

Stilbite. A crystallized simple mineral, usually white, one of the
Zeolite family, frequently included in the mass of the trap
rocks.

Strata, Stratum. When several rocks lie like the leaves of a
book, one upon another, each individual forms a stratum ;
—strata is the plural of the word. £tym., stratum, part of a
Latin verb signifying to strew or lay out.

Strike. The direction or line of bearing of strata, which is always
at right angles to their prevailing dip.

Syenite. A kind of granite, so called because it was brought from
Syene in Egypt.

Synclinal Axis. When the strata dip in opposite directions
towards a common central imaginary line, it is called a syn-
clinal line or axis. ee

oa

Talus. When fragments are broken off by the action of the weather
from the face of a steep rock, as they accumulate at its foot,
they form a sloping heap, called a talus. The term is borrowed
from the language of fortification, where talus means the out-
side of a wall of which the thickness is diminished by degrees,
as it rises in height, to make it the firmer.

Tertiary Strata. A series of sedimentary rocks, with characters
which distinguish them from two other great series of strata,—
the secondary and primary, which lie beneath them.

Testacea. Molluscous animals, having a shelly covering. Etym.,
testa, a shell, such as snails, whelks, oysters, &e.

Thin out. When a stratum, in the course of its prolongation in
any direction, becomes gradually less in thickness, the two
surfaces approach nearer and nearer; and when at last they
meet, the stratum is said to thin out, or disappear.

Trap and Trappean Rocks. Volcanic rocks composed of felspar,
augite, and hornblende. The various proportions and state of
aggregation of these simple minerals, and differences in exter-
nal forms, give rise to varieties, which have received distinet
appellations, such as basalt, amygdaloid, dolorite, greenstone,
and others. The term is derived from ¢rappa, a Swedish word
for stair, because the rocks of this class often occur in large
tabular masses, rising one above another, like the steps of a

staircase.

143

Travertin. A concretionary limestone, usually hard and semi-
crystalline, deposited from the water of springs holding lime
in solution. tym. This stone was called by the ancients
Lapis Tiburtinus, the stone being formed in great quantity by
the river Anio, at Tibur, near Rome. Some suppose travertin
to be an abbreviation of trasteverino from trans-tiburtinus.

Tuff or Tufa. An Italian name for a variety of volcanic rock of
an earthy texture, seldom very compact, and composed of an
agglutination of fragments of scoriz, and loose matter ejected
from a volcano.

Turbinated. Shells which have a spiral or screw-form structure.
Etym., turbinatus, made like a top.

Unconformable. See Conformable.

Veins, Mineral. Cracks in rocks filled up by substances different
from the rock, which may either be earthy or metallic. Veins
are sometimes many yards wide; and they ramify or branch
off into innumerable smaller parts, often as slender as threads,
like the veins in an animal, and hence their name.

Wacke. A rock nearly allied to basalt, of which it may be regarded
as a soft and earthy variety.

Zeolite. A family of simple minerals, including stilbite, mesotype,
analcime, and some others, usually found in the trap or volcanic
rocks. Some of the most common varieties swell or boil up
when exposed to the blow-pipe, and hence the name Zew, zeo,
to boil, and Asbos, Lithos, stone.

Zoophytes. Corals, sponges, and other aquatic animals allied to
them, so called because, while they are the habitation of animals,
they are fixed to the ground, and have the forms of plants.
Etym., Guo, zoon, animal, and gerov, phyton, plant.

ERRATA.

Insert a comma after above, in line 24, page 17.

Add an s to limestone, in line 26, page 30,

For strata, read stratum, in 3rd line from bottom, page 35.
Dele the word which, in line 26 of page 104.

For becomes, read become, in line 12, page 105.

(227)

; f
VAt : { Plate No.|L.
‘PROFILE 4 |
to ac Comper: )
the Geological Reconnoissance |
ot the j
SLAKE of VIRGINIA i |
PROF. WILLIAM B. ROGERS.
1836. : ; ge cr:
Limestone ey QuartzVein GO Amygialoid =| Gi) gil! oo
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Throug out this Section the lowest rock is a grey and red fossiliferous Sandstone, upon this

\Grey and Red Sandstone enclosing Anthracte

contain Gold

Limestones and Slates with Calcareo f

lower stratum is Miocene Shell M

Richmond

a) he upper stratiun is Dikuvial Sand and Grav

4

Peet. ol

eee eed

*

Suite ous Limestone ,being Sometimes a Calcareous Sandstone ; over this a thick group of fossiliferous brown

Between the Rivanna and the Coal Field,occur Gneiss , mica slate, hornblende §

'

See, ame -

Se- 23 CORTE,

d Slaty Sandstones

Between the W. base af tl

( 4]
mary Schists, also Dykes of trap , and V

Eocene Green Sand

ae Blue Ridge and the Primary Group occur Sandstones and Slates greatly ndurated.ar

Che.

d altered by Dykes and Beds? of Trap and Porphyry? and Veins of Quartz some of which

sapeake Bay |
near Old Pow (orator

COTE FO Teer eer ee Tet Py... Fah hit ie.
. + a e- . velo 8 aqtawte gy PF SE P

ty ACCOR psu

the Geoloqicai Reco

(the
SVALYE of VIR tIN LA.
PROF. WILLIAM B.ROGERS.
Seale hall an uch loa wit
S36
Limestone peal Quartz Yem \myddalord
Sandstone Quartz Pas Shale
Conglomerate ies Felspar | lron Ore

Slate Bs Miea [~ Sandstone very

Coal Tale pp Grystallme .

Arenaceous or
} Suiceous Limest.
. Ditto Slate ie 4 : : ~4
+ heme preva Pe ' \ An extensive Sandstor

Sandand Gravel My Hornblende

,

ai

group fills the Space hetween the Ohio Bud the top of Little Sewell | Mach of the rock is very Saliferous especially ig the inferior heds : near ‘hc Seri hae Sood beds of Bitununous Coal and from Elk river wes} ay
. Y te oveasional thin St
, § s eoasional thin St

rata of fossiliterous Limestoneand Hivdrauhe Cement.

s

\ ; 7 : > ‘ > /

bail
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Throughout this Section the lowest rockis a drey andredc fossiliferous Sandstone; upon this a thin fossiliferous Limestone beind & nes oValeareous Sandstone ; over thisa thick droup of fossiliterous brown Slates and Slaty Sandstones
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. . ‘ Ql, . } } . A \ ; a Cte "4 ° M4 - et +5 ML N 4 . r 4 ¢ or oe ae :
Grey and Red Sandstone enclosing Anthracite . Limestones and Slates with Calearco Sihecous Beds aud thm seams of dagk } lint Between the W. base of the Blue Ridse and the PrtusryGroup , Qccur Sandstones and Slates sreatly mdurated and and altered by Dykes and Beds? of Trap and Porphyry ? and Vems of Quartz Some of whi
s.
; ; Kes, ,
iD Se Gin Sal] Seif EGS Nea “i WRENN G OAMHIK G YN; ih LEY INE ERIN PRON Says Nix
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i; 5 . oz : . b mé a . ~¢ <% — LO —— a .
contain Geld. i Betwoen the Rivnnna aud the Coal Meld oceur Gneiss mien xs ate, hormblende Slate and other Primary Schists also Dykes of t ap ane Yems oj % Gress
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eet SEN oe ey ~Z 78 2. Se ee : 25, Sl I 2 ee EM ; Sn ae mee ee at i Oe ee ee oso
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* ag: ns -— — —— — —o _ _-_ - = — nomena wes eens ‘ ¥ a aecnaand 83 — rs a . ane -- ae ——— — ee — a ‘ : : x i e+ s a --- vs oe a. nt a é |

Pituminous Coal Bield. | Gneiss Scans hata Rocene Green Sand. |

*. ,
POCOSIN =) COUNTRY s ; CHESAPEAKE RAY 7
San. es ee a hearold PointComfort. FE. . /

The lower stratum is Miocene Shell Marl; the upper stvatamis Diluvial and Gravel i