xt72jm23bs23 https://exploreuk.uky.edu/dips/xt72jm23bs23/data/mets.xml Kentucky. State Geologist. 1882 books b97-20-37305740 English Yeoman Press, : Frankfort, Ky. : Contact the Special Collections Research Center for information regarding rights and use of this collection. Geology Kentucky Mercer County.Linney, W. M. (William M.) Report on the geology of Mercer County / by W.M. Linney. text Report on the geology of Mercer County / by W.M. Linney. 1882 2002 true xt72jm23bs23 section xt72jm23bs23

GEOLOGICAL SURVEY OF KENTUCKY.

JOHN R. PROCTER, DIRECTOR.

REPORT

ON THE

GEOLOGY OF MERCER COUNTY.

BY W. M. LINNEY.

STEREOTYPED FOR THE SURVEY BY MAJOR, JOHNSTON & BARRETT, YEOMAN PRRSS FRANKPORT, KY.

This page in the original text is blank.

INTRODUCTORY LETTER.

HARRODSBURG, Ky., December, i882.
JOHN R. PROCTER, Director Kentucky Geological Survey:
DEAR SIR: I have the honor to present herewith a Report
on the Geology and other natural features of Mercer county.
Owing to the fair exposure in this county of the lower
rocks seen in the State, I have given more than usual space
to the description of those which lie beneath the Hudson
River Group.
Much work will yet have to be done in those rocks before
all their physical and life-history will be thoroughly unveiled;
yet I do not hesitate to express my judgment in regard to
problems which have arisen. My only regret is, that the
absence of other language has necessitated me to use more
technical terms than I should desire.
Yours, very truly,
W. M. LINNEY

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GEOLOGY OF MERCER-' COUNTY.

TOPOGRAPHY, &C.
Mercer county was constituted from a part of Lincoln
county in I 785. Its position is near the center of Ken-
tucky; and, according to the Report of the Auditor of State
made in I878, contained one hundred and forty thousand
acres of surface. More recent enactments of the Legis-
lature have somewhat reduced this acreage by cutting off
two small areas and adding them to Anderson county. The
population in i870 was thirteen thousand one hundred and
forty-four, and in 188o, fourteen thousand one hundred and
forty-two.
Harrodsburg, the county seat, has a population of twenty-
two hundred, and is the oldest town in the State. Here is
situated Daughters' College, one of the best female schools
in the West, numbering among its graduates some of the
best educated and most accomplished women of the country.
With the above institution, a graded school in Harrodsburg,
and the common schools of the county, Mercer enjoys more
than the average facilities for the education of her youth.
The Cincinnati, New Orleans and Texas Pacific Railway
traverses the county from north to south. Connecting this
route with Harrodsburg is the Southwestern Railroad, four
miles in length. Those two lines give all the needed facilities
for travel and shipping. The Kentucky river flows along its
northeastern boundary; when the proposed improvements on
this stream are completed, steamboats will regularly visit a

GEOLOGY OF MERCER COUNTY.

number of landings in this county. Mercer has Anderson and
Woodford on the north, Woodford, Jessamine, and Garrard
on the east, Boyle on the south, and Washington and Ander-
son on the west.
The eastern and northeastern boundary line is a tortuous
one, following the remarkable windings of Dix river to its
mouth, and continuing with the Kentucky river to the Ander-
son county line. This boundary lies in a deep gorge hun-
dreds of feet below the general surface; and the small
streams which enter the rivers here run also in narrow
channels. The general surface of the eastern half of the
county, away from the cafnon-like valleys, is either in level or
in rolling tracts. Situated on these tracts are the finest lands
in the county, where fields give their largest returns and pas-
tures their richest herbage.
Salt river, here a small stream, winds its way through the
middle of the county, nearly parallel with the flow of the
rivers mentioned above. Its bed is not much depressed
below the surface of the county, and the streams which enter
it have no high bluffs and no rugged channels. The drain-
age is more gentle on the eastern than on the western side.
Some very good bottom lands are situated in its valley; and
its flow is sufficient to give power to a number of mills which
are erected on its banks.
Chaplin river, here also a small stream, runs through the
southwestern part of the county It, like the branches which
flow into it, winds in deep channeled lines among steep
rounded hills. Several mills are favorably situated on this
stream, and the water-power is sufficient to run them the
larger part of the year.
Those rivers all have their flow toward the northwest, thus
agreeing with the dip of the rocky floor of the county. Salt
river falls nearly with the slope of the strata; the others do
not conform to this feature. West of Salt river the county is
usually much broken, hills succeeding hills everywhere.
As seen here, the varying features of cliff and hill, of level
and gentle undulations, are ever pleasing to the eye. On

GEOLOGY OF MERCER COUNTY.

Dix river and on the Kentucky river are views which rival, if
they do not surpass, those of many world-famed localities.
Great walls of massive rocks reach high above the narrow
valleys, rent apart by the forces which elevated them from
an immense depth. They are marked by fractures, and fash-
ioned by time into many imitative forms. Giant chimneys,
castellated ruins, odd faces, and many o:her pictures grow
into form, as fancy leads the eye among fractured stones,
stained by ages and shaded with shrub and vine.
From the high escarpments one may look down upon the
flowing river, shaded with hoary sycamores and drooping
maples, or he may look across into small inaccessible caves,
where swallows and vultures build their nests, and bats in
slumber pass the day. From among those cliffs come forth
the purest. sweetest waters, which bubble over strange moss-
covered stones, and around which rare flowers shed their per-
fumes. Every succeeding year brings an increased number
of visitors to High Bridge and to Pleasant Hill, the village
of the Shakers. They come to see the picturesque views
near those points; but up and down the river are many more
which are hardly known save to the local fisherman who has
an eye for beauty, or to the strolling naturalist, who accident-
ally falls upon them in his tramps.

PALAIEOZOIC GEOLOGY.
The bedded rocks which are exposed to investigation in
Mercer county are about eight hundred feet in thickness, and
are the same that are seen across Dix river, in the lower part
of Garrard county. They are not cut to such depth in the
gorge of Dix river as those seen at Cooper's branch, on the
Kentucky river, as mentioned in the Report on Garrard.
All the beds in the county belong to the Lower Silurian
Age. Beginning at a depth of two hundred and twenty-five
feet in the Chazy Group, they extend to and include half of
the Middle Hudson River beds. The following section illus-
trates the divisions, with their position and thickness:

GEOLOGY OV MERCER COUNTY.

Feet. Feet.

Lower Saurian-
Trenton Period.. Hudson River Epoch.. Middle Beds.... 751
Lower Beds.... 200f 275

Trenton Epoch.... Trenton Group. 1751
Birdseye Group 1301 305

Canadian PeriodChazy Epoch......... .2....... .5 . 22

Total..... ....... .. .. . .. ..... .. . .. .. 8_

CANADIAN PERIOD.
No attempt has been made to separate the rocks of the
Canadian Period into the divisions that are made in the East
and the North. It is probable that they will be found to
include at least a portion of the Quebec Group, whenever
they shall have been thoroughly studied. Till then, the whole
series can be left in the Chazy Epoch.

Ohazy Epoch.-The Chazy Limestones are the lowest
rocks seen in Mercer county. They do not rise to the gen-
eral surface, but constitute, in part, the walls of the deep
gorges in and along the eastern border of the county. East
of Harrodsburg. on Dix river, they are seen about two hunl-
dred and twenty-five feet thick; at High Bridge they are a
little less than that above the water; at Munday's Laniding
one hundred and thirty, and at the Andersoni county line
about ninety feet above the river. The dip which carries
them down is continued with the stream until, at Tyronie, in
Anderson county, they are at the river's level. Along this
whole distance they can be followed with ease, and their dis-
appearance noted.
These rocks, wherever seen in Kentucky, present the same
features-those of great bedded rocks- marked with fractures
and stained by time. At many exposed places they appear
as if they had been bedded in twenty, thirty, or forty feet

GVOLOGV OF MERCER COUNTY.

layers, yet more often exhibiting layers of one to two feet,
and sometimes even less. Never coming to the surface of
the county, they can give to it no agricultural features.
Many of the layers are compact and tough; are capable of
sustaining great weight without crushing, and are, therefore,
well suited for massive foundations and solid superstructures.
The old "Towers " and the heavy masonry for the support of
High Bridge over the Kentucky river, were constructed, in
great part, from the Chazy Limestones. Quarries could be
opened in them, and the world supplied with building stonies.
A number of the beds are dark and fine-grained, but have
yellow lines ramifying through them. Those lines are the
impressions of plants which grew in the old ocean, where
those rocks were formed. Those impressions or casts seem
to be largely composed of silica; and if so, it must have
resulted from the decomposition of plants which secreted that
mineral. Some of these plant impressions are, in their com-
pressed condition, over two inches broad, and have branches
equal to the stems. There is often some carbonaceous matter
around those impressions and between the layers of stone.
Some few of the beds are gray and are half crystallized;
others are of light or of dark dove-color, occasionally hav-
ing a partial birdseye structure. Some layers are coarse, but
the most of them are fine-grained. In composition, they are
mostly carbonate of lime, having in addition magnesia, silica,
clay, &c. In a part of them, the planes of deposition are
very regular; but in others, particularly those Containing the
large sea-weeds, the lamination is irregularly waved. The
latter have a peculiar blotched appearance, on some angles
of fracture, that is very interesting.
Those rocks have, in time, been fractured in lines which
reached through every layer; and those fractures agree usu-
ally with angles and lines of the river bed, or extend across
the country from one bend to another. Usually there is a dip
away from the river. The fractures add much to the ease
with which the rocks can be quarried for building purposes,
or for the construction of roads to the river.

GEOLOGY OF MERCER COUNTY.

Some of those layers have their upper surfaces plated with
chert, while, through a few of them, are thickly seen small
crystals or flakes of iron pyrites. In two or three layers the
rocks have been crushed, forming very pretty breccias. Good
specimens of fossils are hard to obtain from these rocks.
Macurea magna, a large coiled shell, is not uncommon in the
upper portion. They are seen only as casts in the tough
heavy layers, and are hard to remove without shattering them
to pieces. Orthis cos/alis is to be found quite frequently at
one horizon on Dix river, near Spillman's Mill, but never in
fine condition. These are characteristic fossils of the Chazy.
With them are associated some other known forms, and quite
a number which have not been identified.

TRENTON PERIOD;
The rocks of the Trenton Period in Kentucky have been
a subject for some very unsatisfactory discussions; and if I
shall be able to refer them to their appropriate places in the
geological column, something will have been done toward set-
tling some controverted points in the geology of the Ohio
Valley. The divisions seem to me to be as well marked as
could be expected at the same distance, in any direction, from
the typical beds shown in New York. For the present they
will be described under the Birdseye, Trenton, and Hudson
River Groups.

Birdseye Group.-The Birdseye Group has two distinct
characters here: first, it has some magnesian limestones at
the base, and then some pure limestones above.

Maguesian Limestone.-The lower part of the Tren-
ton Period in New York is represented as having len feet of
bff limestones in its lower part. At the base of the Birdseye
in Kentucky are ten feet of rocks which, on exposed faces,
are a dirty buff color; internally they are gray or a grayish-
brown. Sometimes part of the layers are blotched with dark
blue. They are true dolomites, containing from twenty-nine

GEOLOGY OF MERCER COUNTY.

to forty per cent. of magnesia, and fifty-one to fifty-six per
cent. of carbonate of lime.
These rocks have been termed " Kentucky Marble," and
have been used to some extent for building purposes; exam-
ples can be seen in the Clay Monument at Lexington, and in
the columns of the State House at Frankfort. The character
and the thickness of these beds are very uniform whenever
seen. In Clark, Fayette, Jessamine, Garrard, Boyle, Mercer,
Woodford, and Anderson counties, they occupy the same
position, immediately on the Chazy, and disappear with the
latter, when it becomes lost beneath the drainage of the
rivers.
This stratum is quite regularly bedded, generally consisting
of one four foot layer and several thinner ones. Often, in
long continued exposures, the heavy layers are split into
thinner ones. On exposure the blue spots first become of a
reddish brown, and afterward fade into the common buff usual
with the rock. This stone is easily quarried; its even-bedded
layers, and its uniform thickness, make it desirable. It works
fairly under the hammer, and the layers can be readily and
evenly split. It does not usually wear as well in the cliffs as
some of the rocks below or above it, but it must be quite a
durable stone.
There are no fossils contained in this rock, unless those
blue blotches seen on freshly fractured surfaces are due to
the remains of sea-weeds, to which they have some faint
resemblance at times. These layers have been used along
the line of the Cincinnati, New Orleans and Texas Pacific
Railway in the construction of heavy masonry as far south
as Mississippi. Like the most of magnesian limestones, they
sometimes exhibit stylolites.

Birdseye Limestones.-Resting on the Magnesian
Limestones are about one hundred and twenty feet of mostly
gray or dove-colored limestone. The exceptions are near
the bottom, where there are a number of layers strongly
resembling the tough, heavy beds of the Chazy. The gray

I I

GEOLOGY OF MERCER COUNTY.

layers are partly crystallized, and are usually thin-bedded.
The dove-colored are often heavy bedded and brittle, break
with a conchoidal fracture, and are marked with strings or
specks of calcite; the latter feature marking the former pres-
ence of fossils.
Near the middle of this group are a number of layers,
which include some singular markings, which have been
referred to a sea-plant, described by Prof. James Hall under
the name of Phytopsis tubulosa. The long stems appear
horizontal in the beds, and from them, at intervals, are ver-
tical branches, one fourth to one half an inch in diameter.
Those on the worn upper surface of the rock have a fancied
resemblance to the eyes of birds; hence the name birds-
eye now including under it other structures, not only those
marked by this plant, but all which have such specks and
strings of calcite through them. The layers holding the
typical birdseye structure are very fine-grained soft limestone,
which, if it were not for crystals of calcite, and sometimes
iron pyrites, might be used as lithographic stones; they are
not all crystallized, are easy to dress down, and are very
pretty when polished, though they have no glistening surface
like marble. Near the mouth of Shawnee Run, on top of
the cliff, are some of those layers on the surface in which the
structure is finely marked.
In the Birdseye Group are a number of very smooth, uni-
formly bedded layers which quarry easily, work well, and
appear well in structures. Some of the stone houses at
Shakertown were erected of this material, and, although
it has been exposed since 18o9-i825, it has preserved its
external qualities very well.
The lower portions of the Group, which are marked with
plants so strongly, present some curious surfaces at times.
Along some of the old fractures, where for ages decompo-
sition has been going on, the walls have an honey-combed
appearance. The old casts of plants have leached out, leav-
ing their tortuous lines as holes extending into the rocky face,
as if they had been made by the boring of worms.

GEOLOGY OF MERCER COUNTY.

At Shakertown there are several large kitchen table tops,
made from the plant layers of the Birdseye Group, on whose
polished surfaces the outlines of plants, with the bifurcation
of the branches and their flexible characters, can be distinctly
traced. The colors of the tracings are in contrast with the
body of the stone, which gives to the whole a peculiar marble-
like appearance.
Above the middle of those beds are some intercalated
shales, containing thin plates of limestone filled largely with
species of retepora, ptilodiclya, orthoceras, stropbhomena, and
often large masses of Tetradium fibratum are included in it.
Individuals of a small bivalve crustacean, Leperditia canadensis
(Jones), are very numerous.
The upper portion of the Birdseye contains much chert,
and the top layer is everywhere plated with a two or three-
inch layer of it. This chert is largely made up of fossils; but
their condition in the matrix is such that it is very difficult to
obtain more than fractured specimens. A stroma/opora, Cot-
umnaria alveotata, and Tetradium fibratum, variety apertum,
may be mentioned. The latter, however, is seen through
more than half of the section.
Some of the fine-grained layers of this group show beautiful
marks of lamination, and those sometimes split into good
even flag-stones. No agricultural features of note are given
by the decomposition of those rocks. The surface features
formed from them are only fringing tracts along the river and
creek bluffs on the eastern part of the county, and are more
often, where the trees have not been destroyed, covered over
with red cedar, growing into large trees where the soil is
deep, or more shrubby where they are rooted in the fractures
of the beds. The upper part of this group is the probable
equivalent of Dr. Safford's Glade Limestone of Middle Ten-
nessee.
Trenton Group.-The rocks which constitute the Tren-
ton Group, in Mercer county, are not of uniform appearance
or composition, and for convenience of description, may be
divided into four divisions;

GEOLOGY OF 'MERCER COUNTY.

Feet.
Uppe Birdeye ...............
Granular Limestone ................ . . . .. . . -. . 25
Blue-grass Beds...... .. .. ... .. .. .. .. ... .. .. .. . go
Silicious Limestones...... .. .. ... .. .. .. ... .. .. .. . 30

Suicious Limnestones.-These beds lie at the base of
the Trenton Group, and immediately on the Birdseye Lime-
stone, and have the position of the Black River Group in
New York, and the Carter's Creek Limestone in Tennessee.
There is no place where a complete section can be seen of
these rocks. They are quite silicious, very argillaceous, and
generally heavy-bedded. They appear to decompose rapidly.
and are usually overlaid with heavy beds of clay, containing
a number of silicified fossils and very curiously-shaped nod-
ules of chert, which have heen liberated in their deconiposi-
tion.
The rocks are coarse-grained and gray, often appearing as
if more than half crystallized-rugged where exposed long
to the atmosphere; and in exposures where they have been
recently uncovered, appearing as if their surfaces were de-
composed under the soil more rapidly than above it. Some
of those layers exhibit a concretionary or wave-like structure,
the laminx being contorted.
The clay beds derived from these rocks are sandy, and
where cultivated as soils, are disposed to cut rapidly into gul-
lies. There are many farms on the bluffs of the Kentucky
river which have many acres of land ruined from this cause.
A number of fossils have been collected from this horizon.
Tetradium columnare, Columnaria alveolata, Recep/aculites nep-
tuniiP Palaeophycus simplex, Sirep/elasma aper/um may be
mentioned, and these are associated with a number of species
of crinoids and forms of the orthoceratite family.

Blue-Gras Beds.-During the progress of the uncom-
pleted Geological Survey of the State, made by Dr. Owen,
Maj. S. S. Lyon suggested the above name for a part of the
Lower Silurian area of Kentucky. Nothing could better rep-
resent the surface features as exhibited over a series of soils

GEOLOGY OF MERCER COUNTY.

seen in the central part of the State. For those soils are
preeminently the soils where the- blue-grass attains its most
luxuriant character, and they have been derived from the
destruction of the beds now to be considered.
About ninety feet of rocks are included- in this division.
Near the base are usually some layers of hydraulic lime-
stones. Those are sometimes a dark gray on the surface,
with a blue nucleus when broken, are composed of lime and
clay, are often without fossils, yet are sometimes filled with a
thin form of Or/his testudinaria. These layers are often
absent, and usually few in Mercer.
The rest of this bed is made up mostly of gray limestones,
though there are a number of dark blue ones to be seen.
Many of the layers are heavy in some deep opened quarry
or cut, yet appear as thin-bedded rocks on natural exposures.
Between them are often interposed shales. The shales, and
sometimes the rocks, are sandy. The sand is largely lime
sand, though there is some silica in it. The decomposition
of these rocks and shales seems to be rapid and uniform.
They give the most level lands in the county, and the best
soils in the county and in the State. They seem to contain
every element in the best proportion to form the richest soils.
These soils, in addition to their being the peculiar home of
the blue-grass, are the same on which is grown nearly all of
Kentucky's great staple-hemp. In the cereals, these soils
outrank all others in the State in producing the largest returns.
About one third of the county of Mercer contains soils de-
rived from those rocks, and on them are some of the most
beautiful and highly productive farms in the State.
The Blue-Grass beds are not seen west of Salt river in this
county; they all lie between that stream and the eastern
boundary of the county. Their general character can be
seen along the cuts made for the Cincinnati Southern Rail-
road, north and south from Burgin. A great number of fos-
sils are seen, many of which have not been determined. A
list of a number of them is given in my REPORT ON THE ROCKS
OF CENTRAL KENTUCKY. These beds are doubtless the equiv-

I 5

GEOLOGY OF MERCER COUNTY.

alents of Dr. Safford's ORTHIS BED, which forms the finest
soils of Middle Tennessee. Some of the upper layers are
covered with wave marks, showing a shallowing of the sea
floor where they were laid down.

Graulbar Limestone. On the real Blue-Grass beds
there are usually to be seen, where it has not been eroded
away, some heavy bedded gray granular limestones. They
appear on the outside, and often internally, as sandstones.
'this peculiarity is doubtless due to some manner of crystalli-
zation, as the fossils which are included have undergone the
same change. Besides, they can be traced to where this
character is not so prominent, or is almost lost. Two miles
east of Harrodsburg, one layer of this bed is seen three or
four feet thick. Masses of this layer are often seen above
the. ground, appearing as boulders which have been trans-
ported from a distance. On the Munday's Landing road
quarries were opened in this bed for material to construct
a lock and dam on the K entucky river. The lower layers
are evenly bedded, and are often thin enough for flagging;
they are often used for foundations and- fences. At some
localities some of the layers have a rose tint.
There are quite a number of caves and underground drains
within those beds. Its granulated character makes it easily
acted upon by carbonated waters. These acting along old
fractures have destroyed the layers more readily decomposed,
-and produced the subterranean cavities.
A number of large bold springs are to be seen in the
county, which have their origin in the peculiar character of
this rock. The Boiling Spring in Harrodsburg, and Fountain
Blue, northwest of that place, are locally well-known exam-
ples. Several large species of /ame//ibranchs, one or two forms
of orthoceras and Tetradium fibratzim are common in those
layers, as are also large specimens of Stromnatapora rugosum.
All of them are largely destroyed by the granulation to which
they have been subjected.
These limestones evidently occupy the place of the Capitol

GEOLOGY OF MERCER COUNTY.

Limestone, of which the State-house at Nashville was con-
structed. Here it is not so dark as it is in Tennessee; other-
wise it is much like it.
These layers are often selected in Mercer county as the
material for lining the backs of grates and fire-places, and are
locally called fire-rocks. (Perhaps the mechanical arrange-
ment may make it resist fire better than denser rocks.) I
know of no other reason that would give it a preference over
many others for the purpose.

Upper Birdseye Beds.-Those beds which must oe
referred to the Dove Limestone, which overlie the Capitol
Limestone, in Dr. Safford's section at Nashville, are a local
phase of the Trenton in Kentucky, as they are'in Tennessee.
The greatest thickness of the Upper Birdseye, including
several local features which overlie the typical layers, is about
twenty-five feet. The following section, as exhibited in one
of the quarries in 'Harrodsburg, will illustrate the particular
layers. The Hudson River Group overlies the upper part:

No. Feet. Inches.

1 Layer containing large stromatopora .......... . . . 1 4
2 Lumpy layer with Orthi borealis and Orthis lynx .1 6
3 Uneven bedded blue limestone. 1
4 Lumpy limestone with Orth borealis. . . . 10
5 Grey limestone................ . ... . 4
6 Lumpy limestone............... .. . . . . 10
7 Partial birdseye limestone ........ . . . .6. . .. 6
8 Dark birdseye limestone. . ...... .. . . . 2 to 4
9 Soft sandstone.. .. .. .. . .. . .. . .. . .. . .. . 2 to 4
10 Light dove limestone. ............... . . . .. .. 6
11 Light dove limestone. . .. 6
12 Clay ....2
13 Blue clouded birdseye limestone. .......... 8
14 Light dove birdseye limestone....... . ..... 2
15 Light dove birdseye limestone ............ . 1 10
16 Blue clouded birdseye limestone. 2 . . .
17 Carbonaceous shale.. . I
18 Dark dove birdseye limestone, with green specks ... . 10
19 Dark dove birdseye limestone, with green specks. 1 6
20 Light birdseye limestone........ . .. . .. . .. . ... 10o
21 Blueish gray partial birdseye limestone. . . . 7
22 Graptolite shale ............... . . . .... 1. .. 1
23 Blueish dove birdseye limestone . . ..... ... .. 2j
24 Blueish dove birdseye limestone.. . .. 2j
Total.. . .. .. . .. . ..1.7... . .. . .. . . .

GEoLOG. sua.-2

GEOLOGY OF MERCER COUNTY.

The dove-colored layers are very much like the Birdseye
layers one hundred and fifty feet below. They are fine-
grained, brittle, pure, and take a fine polish. One familiar
with both horizons would not always be able to refer selected
specimens to their places. This uniformity of structure has
led to a number of errors in noting the position of these beds,
and those associated with them. They are rarely uniform for
a mile together.
The heavy layers have been much used for masonry at
Harrodsburg, and are very durable. At several points one
or two layers have been crushed some time in the past, and
cemented into beautiful breccias. Some of the layers are at
times black, and not unfrequently contain small cavities filled
with petroleum. One or two layers of shale contain grapto-
lites, but they have not been submitted for determination.
The thin layer of sandstone is often seen in its horizon,
and sometimes almost amounts to a conglomerate. Some-
times the presence of iron pyrites injures a layer for some
distance in the quarry.
The lumpy layers do not seem to be concretionary; the
fossils in them are usually crushed, showing more than ordi-
nary compression among the materials; they break into very
irregular lumps on exposure, or when an attempt is made to
quarry them. At times, in this horizon, is a silicious layer,
sometimes a foot thick, which has the character of a buhr-
stone. Species of cyrlodonta. orthoceras, murchisonia, and
other shells seem to have been swept into depressions, and
there cemented with silica, their cavities filled with the same
mineral, and then the lime of the shells leached away.
In Mercer county the fossils in the heavy layers have not
become silicified; yet in Boyle county, ten miles away, and
near where the KENTUCKY ANTICLINAL crosses the county,
they have all been replaced with silica.
Two or three of those dove limestones contain vast num-
bers of valves of leperditia. There are two species, and are
probably those described by Dr. Safford as Leperdilia capax
and LePerditia morgani,

GEOLOGY OF MERCER COUNTY.

The presence of those leperditia, of several species of
cyr/odonla and murchisonias, with Rhynchonella increbescens,
Tetradium fibralum, Be//eropfihon troosti, Ort/zoceras capi/ofinum,
Lichas tren/onensis, here in close association, evidently marks
in part Dr. Safford's Middle Nashville Beds.
These beds are certainly lower than any exposed at Cincin-
nati; and the presence of such undoubted Trenton forms as
Or/his borealis, Arthraria anhiquata, Siromatotora rugosa, &c.,
in and near this horizon, would seem to be sufficient, without
the close relation existing in lithological characters, to place
them in the Trenton.
The top layers in the Birdseye here contain a large Siroma-
lopora. It has been crystallized, and thus the structure largely
destroyed. In some cases it is seen to be covered with pim-
ples, and probably should be referred to Stromatopora pustu-
losa (Saff.)
There were certainly a number of changes which took place
over this region about the time of the completion of the Tren-
ton Group. The patch-like character of some of the beds,
the formation of breccias, the invasion of sand, the opening
of veins and their injection with barytes, lead, and zinc, all
testify to changing conditions and local disturbances. When
examined, the Stroma/opora bed seems to have begun as a
reef, but ended in being buried in silt.
The soils made from the Upper Birdseye are not exten-
sive ones; they lie in narrow lines and patches immediately
around the Blue-grass Beds, and may be ranked as fair. The
resisting character of the heavy dove layers often leaves them
exposed, the soils having washed from over them.

Hudson River Epoch.-The rocks which have been so
far described are seen only in quite a limited portion of Cen-
tral Kentucky, and mark, by their outlines, the most deeply-
eroded portions. While seen in a number of counties, there
is not a single one of them but exhibits, somewhere within its
limits, higher rocks. Those rocks which, in the blue lime-
stone region, overlie the Trenton Group, are of the HUDSON