KENTUCKY GEOLOGICAL SURVEY, J. R. PROCTER, DIRECTOR.

Kentucky Fossil Shells

OF THE

oi Kentucky

BY HENRY jN ETTELROTH, C. E.

FRANKFORT, KENTUCKY

ELECTROTYPED AND PRINTED BY E. POLK JOHNSON, PUBLIC PRINTER AND BINDER -

1889.

KENTUCKY GEOLOGICAL SURVEY, J. R. PROCTER, DIRECTOR.

Kentucky Fossil Shells

A MONOGRAPH OF THE FOSSIL SHELLS

NTUCKY GEOLOGICAL SURVEY and STATE MUSEUM,

FRANKFORT, KY., U. 6. A.

HH THE COMPLIMENTS OF

JOHN R. PROCTER,

DII5ECTOIS.

1 ' J

BY HENRY NETTELROTH, C E.

FRANKFORT, KENTUCKY

ELECTRQTYPED AND PRINTED BY E. POLK JOHNSON, PUBLIC PRINTER AND BINDER

1880.

KENTUCKY GEOLOGICAL SURVEY, J. R. PROCTER, DIRECTOR.

Kentucky Fossil Shells

A MONOGRAPH OF THE FOSSIL SHELLS

OF THE

Silurian mid levonioii flocks of hntuGky

I L L V V hJ

V

BY HENRY NETTELROTH, C E.

FRANKFORT, KENTUCKY

ELECTROTYPED AND PRINTED BY E. POLK JOHNSON, PUBLIC PRINTER AND BINDER

1889.

COPYRIGHTED BY KENTUCKY GEOLOGICAL SURVEY, 1889.

K4

TABLE OF CONTENTS.

PAGE.

Letter from the Author. 3-4

A Short Sketch of Geology 5-27

Description of Genera and Species 28-230

Index to Genera and Species described 231 239

Index to Species described 240-245

Plates and Explanatory Text.. I-XXXYI

M65064S

LETTER FROM THE AUTHOR.

MR. JOHN R. PROCTER,

Director Kentucky Geological Survey :

DEAR SIR: The work of describing the fossil shells, or Mollusca, from the
Falls of the Ohio, which you kindly assigned to me some years ago, has,
unfortunately, been delayed by severe illness of several years' duration. It
was only during the past winter that I regained sufficient strength to complete
it. This monograph contains about two hundred and twenty species, forty-
three of which are new, and originally described by me. The descriptions
and illustrations of the balance are scattered over many different State
Reports, Monographs and Periodicals, accessible to only a few persons in
Kentucky, and, for this reason, it was necessary either to copy those figures
and descriptions, or to reproduce them from our own material. All of our
illustrations are original, with the exception of three or four, which are
copied from Prof. Hall's 27th Regents' Report. The drawing and engraving
was done by Mr. Chas. Starck, of the Louisville Lithographing Co., who
deserves great credit for the pains taken and the skill shown in the execution
of this work. Of the original descriptions of known species, I copied some
entirely. Coming, as they were, from the skillful pen of Prof. Hall, it was
impossible to improve them. Others I have remodeled, and some set aside
and replaced by new ones. In many cases, the descriptions were made from
single, not well preserved, specimens, which rarely showed the true characters
of the shells in their original condition, and, therefore, led to errors in the
descriptions. The large and excellent material now found in about a dozen
collections here in the Falls Cities, while enabling me to correct those mistakes,
has also compelled me to change descriptions coming from far superior palae-
ontologists. The larger number of our fossil shells were, heretofore, described
and figured by Prof. James Hall, of Albany, New York, in his numerous
reports and pamphlets, most all of which he presented to me, with the kind
permission to make the broadest use of his illustrations and descriptions. For
such exceptional generosity I can thank him only by this public acknowledg-
ment. The material used in the preparation of this monograph belongs partly
to my own cabinet, and partly to the collections of the following gentlemen :

4 LETTER FROM THE AUTHOR.

Major Wm. J. Davis, Profs. Wm. J. McConathy and J. T. Gaines and Dr.
James Knapp, of Louisville, Ky., Prof. A. C. Goodwin, of Charlestown, Messrs.
Orlando Hobbs, Henry Peters and Mr. Fogg, of Jeffersonville, Indiana. These
gentlemen have rendered me all the assistance I desired or needed, for which
I here express my thanks. To Major Wm. J. Davis, the author of " Ken-
tucky Fossil Corals," I am especially indebted for much valuable information
given me, while on our numerous collecting trips, and during the preparation
of this work. It has pained me to see the valuable collection of the late Dr.
James Knapp, from which Prof. Hall received most of his Ohio Falls speci-
mens, leave our State. Though in corals it was greatly inferior to the cabinet
of Major Wm. J. Davis, and in shells not equal to my own, it contained some
very rare specimens which it may be impossible to replace.

Our shells have generally retained their original form, not having suifered
from compression or distortion, as is the case with so many fossils from other
localities, and their silicification has prevented all wear and rubbing after sepa-
ration from their matrix, while, on the other hand, their changing into horn-
stone has, in many instances, obliterated the original fine surface-markings, for
the study and description of which we have to acquire material from other
localities.

The descriptions of fossils I have prefaced by a short article on geology and
palaeontology in general, containing information indispensable to any one who
wishes to gain an understanding of the fossil remains of the fauna and flora
of former ages. In preparing said article, I have made extensive use of the
works of Dana, Lyell and others.

Hoping that this monograph will meet with your approval, and that it may
be of service to the students of geology, in spite of its many shortcomings,
which, knowing your kind disposition, I feel assured you will overlook or
excuse, I express here to you, dear sir, my many thanks for your kind con-
sideration and indulgence, and remain

Very respectfully, your obedient servant,

HENRY NETTELROTH.

LOUISVILLE, 1887.

FOSSIL SHELLS

OF THE

SILURIAN AND DEVONIAN ROCKS.

BY

A SHORT SKETCH OF GEOLOGY.

A SKETCH OF GEOLOGY.

The name "Geology" is derived from the Greek words "ge," the earth, and
"logos," a discourse, thus indicating a science of the earth, a science investi-
gating the different materials of which the earth is composed, and also the
manner in which these materials are arranged. Geology gives us, also, the
history of our planet from its beginning to the present time — examining all
the processes through which the earth has passed, from its original gaseous
condition until it acquired its present form and structure. It furthermore
enables us to obtain extensive and valuable information about the animal and
vegetable life which covered our globe during bygone ages.

Geology is a science of comparatively recent date, though we find some geo-
logical knowledge among the ancient Romans and Greeks, and in the writings
of the middle age. All that knowledge, however, amounted only to a few
isolated speculations, nearly always based upon erroneous suppositions, and
never resulting in the establishment of a regular system. Geology as a science
was originated during the last century, but received its main development dur-
ing the present one. In spite of its short existence, it has outgrown many of
its sister sciences, and ranks to-day among the most important ones at the head
of the scale. Its founders and chief promoters are mainly found among the
English, German and French savants, and during the present century our own
country has contributed its full share to its advancement. The names of Lyell
and Murchison, of Leopold von Buch and Goldfuss, of Cuvier and Verneuil,
and of our own eminent geologist, Professor James Hall, of New York, and
many others, will be known to the students of this noble science through-
out the coming ages.

Geology has for its territory the whole earth, as far as the same is accessible
to its investigations. These are not confined to the surface, but penetrate as
deep into the interior as artificial excavations for mines and artesian wells
allow. Still greater and better opportunities than these artificial openings,
which are limited in numbers and dimensions, are offered the geologist, for his
researches, by the peculiar figuration of our planet's surface, where deep
valleys alternate with high mountains, and where the strata are bent to such a
degree that we find them at one place deep below the surface, whilst at a dis-
tance of a few miles the very same layers may be outcropping at the slope of
a hill, or may even form the surface rocks of extensive districts.

6 PALEONTOLOGY OF KENTUCKY.

Vast as the geological field appears, and in reality is, it, nevertheless, forms
only a small portion of the whole contents of our globe. The deepest excava-
tions rarely extend to a depth of 2,000 feet below the level of the sea, though
their absolute depth may be greatly in excess of this, inasmuch as most of
them ar<§ in mountainous regions. The bending of the strata very often gives
us an insight into greater depths, but even this amounts only to a few miles,
and forms only a small portion of the earth's radius. Beyond these depths
geology is barred, as far as actual observations are concerned, but its inquiries
may penetrate deeper ; it may speculate about the nature and condition of the
earth's interior. About this matter different theories have been advanced, but
as all of them are based on mere speculation, none have met with a general
acceptance by the scientific world. Whether the center of our globe is solid
or fluid, whether it is a vacuum or filled with compressed air, we are unable
to decide with certainty. Some facts speak for a solid and others for a fluid
center, and still others can not be accounted for by either condition.

Some European scientists, like Leslie and Halley, consider the earth a hollow
sphere, which, according to Leslie, was filled with imponderable material, pos-
sessing an enormous repulsive force. These philosophic speculations of savants
were taken up by Captain Symmes, of Kentucky, who, by adding his own
fantastic dreams, enlarged them to the so-called "Symmes' Theory." Symmes
insists that the interior of our globe is not only hollow, but that it is also
inhabited by animals and plants ; that it possesses a very mild climate, and is
illuminated by two planets, which he calls Pluto and Proserpina. He felt
so convinced of the existence of his subterranean country, that he repeat-
edly extended private and public invitations to Alexander von Humboldt, Sir
Humphrey Davy, and other celebrated scientists of this country, and of the
old world, to accompany "him on his intended subterranean expedition.

ROCKS.

The solid portion of the earth is composed of different materials or rocks.
The term "rock," as commonly understood, signifies a hard and stony mass,
such as granite, quartz or limestone, but in its geological meaning, it embraces
all solid constituents of our globe, the hard and stony, as well as the soft and
incoherent matter ; thus, loose sand and soft clay are just as well included in
that term as basalt and quarrystone. Before geology enlightened the people,
it was the general belief that all the rocks, with their present form and arrange-
ment, were thus created. This belief, though still adhered to by the ignorant
masses, and by bigots, has disappeared from the minds of all who ever came
under the influence of geological reasoning. Geology informs us, that all the
rocks in their present structure, composition and arrangement, are the pro-
ducts and results of many different conditions under which our earth existed,

A SKETCH OF GEOLOGY. 7

and of many different processes through which it has passed during the many
ages of its existence. By whatever influences the rocks may have received
their present characters, they received their original form and structure by the
agency of fire. All the rocks, without exception, passed, in the beginning,
through a molten condition, out of which, by subsequent cooling, they re-
ceived their first form as solids. But in the course of time another agent
appeared and changed many of the existing forms. Water, the powerful
opponent of fire, went into action, and by its chemical, as well as mechanical
influence, dissolved a large portion of the fire-produced formations, and carried
them to distant localities, where, under favorable conditions, they were de-
posited as sediments, forming those rocks which are mainly characterized by
their arrangement into strata or layers. Again, we find many of these sedi-
ment-formations have been subjected to the influence of heat, by which they
lost some of their former characteristics. Their crystallization, and the total
absence of organic remains, prove the action of heat, while, on the other
hand, their stratification, which is generally retained, testifies to their sedi-
mentary origin. Thus we will notice a natural division of all the rocks into
the following three classes :

1. Rocks originally formed by fire and not afterwards changed, the igneous
rocks.

2. Rocks formed in water by sediments, the stratified or sedimentary
rocks.

3. Rocks originally formed as sedimentary deposits, but afterwards changed
by heat, without losing their stratification, called metamorphic rocks.

The igneous rocks are generally subdivided into volcanic and plutonic rocks.
Their difference is caused by the condition under which the cooling of the
molten masses took place. In the volcanic rocks, the molten matter appeared
either on the surface of the earth, or at least very near to the same, where the
cooling was rapid, and where the forming rocks were not subjected to the
heavy pressure of the superimposed strata.

The plutonic rocks resulted from greatly different conditions. Here the
molten masses did not penetrate the surface strata, but remained deep in the
interior of the earth, or at least at the bottom of deep oceans, where the cool-
ing process was retarded, and where the new formations were compressed by
the weight of the overlying layers.

In the column of strata we generally find the plutonic rock at the bottom.
Next above come the metamorphic formations, which are superimposed by
the sedimentary and volcanic rocks. This arrangement led the earlier geolo-
gists to the belief that the plutonic and metamorphic rocks were older than the
others, consequently, they called the lower primary formations, and the upper
the secondary formations. The older school of geologists adhered to the

8 PALJEONTOLOGY OF KENTUCKY.

so-called neptimian theory, according to which all the rocks, with the only
exception of the volcanic lava formations, were considered as produced by
water, or to be of aqueous origin. If this theory had proved correct, the views
of the old school about the comparative age of the different rocks would be
sustained. But progress in geological science has upset the neptunian theory,
and established in its place the plutonic theory, which makes fire or subter-
ranean heat the main agency in the production of the plutonic and met-
amorphic rocks.

This new theory does not admit the classification of primary and secondary
rocks. The first rocks ever produced, which formed the first thin crust of our
globe, were dissolved by water and removed to other localities, where they
furnished the constituents of the sedimentary formations. Even a large
portion of these have been ground up by weather and water, to provide the
material for later deposits. Rocks of all the different classes have been formed,
during the past, simultaneously, and may be in process of formation at
the present time. The terms primary and secondary are, therefore, obsolete,
inasmuch as they indicate the comparative age of the different rocks.

SEDIMENTARY OR STRATIFIED ROCKS.

Though all the different classes of rocks are of great interest to the geologist,
still the most important of all is that including the sedimentary formations.
The rocks of this class are always arranged in layers or strata, and they are,
therefore, generally referred to as stratified rocks. They are of greater impor-
tance to the geologist than the other formations, because they furnish him the
main material for his investigations. Most, if not all, of them have been
formed since the beginning of organic life on our planet, as proved by the
remains or traces of animal and vegetable organism preserved in their strata.

The most important among the different points which the geologist has to
consider in regard to the sedimentary rocks, are : their mineral composition,
their arrangement in strata, their relative age, and, most of all, their organic
remains.

In regard to their mineral composition, we may divide them into three
groups, the siliceous, or arenaceous rocks ; the clayey, or argillaceous rocks ;
and the calcareous rocks, or limestone. The main constituent of the first
group is silica, in the form of quartz-grains or sand ; that of the second group
is clay, a mixture of siliceous matter, with a large amount of alumina and
oxide of iron, and that of the third group is carbonate of lime. It is impos-
sible to separate these three groups by a well defined division line. Some
rocks form a kind of connecting link between the first and second, and others
between the second and third group, while again, others may combine the
siliceous and calcareous rocks. The first group is represented by sandstone,

A SKETCH OF GEOLOGY. 9

the second by shale, and the third by limestone. Argillaceous rocks are
easily identified by the peculiar earthy odor which they emit when breathed
upon, while the limestones may be detected by the aid of muriatic acid, which
causes effervescing when applied to them. Upon sandstone acids have no
effect whatever.

STRATIFICATION. — Stratification is the arrangement of rocks into different
layers or beds. It is a characteristic feature of all the sedimentary forma-
tions. Stratification can only be produced by sedimentation, and the latter
can, as far as geological strata are concerned, only take place in water charged
with solid or earthy matter, which is kept in suspense in the shape of mud.
Solid material has generally a greater density, or specific gravity, than water,
and, therefore, can be kept in suspense by the latter only so long as the lateral
motion of the water overcomes the action of gravitation. As soon as the
water ceases to move, the mud falls to the bottom, where it forms the sediment
which afterwards, under the enormous pressure of superimposed masses,
transforms into solid rock. If such sediment formation had gone on continu-
ously, and always under exactly the same conditions, throughout a whole
geological period, all the rocks of that formation would form a solid, un-
broken mass. But the sediment formation suffered frequent interruptions,
extending over shorter or longer periods, and was subjected to many changes
in its material. These circumstances caused a differentiation in the deposits.
Any interruption of the formation, or any change in the material, were indi-
cated by lines or planes of separation, while the different layers, thus produced,
were distinguished by color and texture.

The solid or earthy materials with which the waters are charged, are derived
partly from the dry land by the influence of heat, frost and rain, and partly
by the never- resting waves of the oceans grinding up the cliffs and beaches of
the seashores. These agencies are employed to reduce the elevations of the
dry lands to the level of the oceans, and, if they were not counteracted by
other forces, would accomplish their task in less than six millions of years.
It is estimated that the average elevation of all the continents and islands does
not amount to fully . one thousand feet ; and, on the other hand, the work
accomplished by denudation is computed to be one foot in six thousand years,
extending over the whole area elevated above the ocean. Such calculations
are only mere approximations, based upon conditions which may change
considerably in the course of time, and should never be used for framing
deductions, without making great allowances. That the work of denudation
must have been different during the different ages of the past, can not be
doubted. There were periods when a very high temperature prevailed all
over the earth, from the poles to the equator, causing a heavy rainfall, and
lending the water a greater dissolving power, circumstances which must have.

GKOL. SUR. — 2

10 PALAEONTOLOGY OF KENTUCKY.

produced greater denudation. Then, again, other periods set in, when the
temperature of our globe was very low, when the excessive heat of former
ages was replaced by excessive cold. Frost is a very powerful agent in the
destruction of rocks. The hardest material which admits water into its pores
will be crumbled to dust by this destructive force. Here, again, denudation
must have been very large. Between these extremes in temperature, our planet
experienced some moderate climate which had not such a destructive influence
upon the solid material of our earth's crust.

STKATA AND LAYERS. — These two terms are generally used as synonymous,
but some geologists make a distinction between them. They use the term
layer for each single member of stratified rock, and apply the term strata to
beds of the same material. Thus, if a section shows in its lower half limestone,
and in its upper half sandstone, it contains only two strata, though it may
show a great many layers.

Layers and strata vary in thickness from an inch, and less, to many feet.
Very thin layers are called laminae, and for thin strata, the term seams is used.
If all the strata had remained undisturbed in their original position, all would
be nearly horizontal, and parallel to each other ; but the many upheavals and
depressions to which our earth's crust has been subjected, have disturbed their
original horizontal and parallel arrangement, and we now find them occupying
every imaginable position in relation to each other. Wherever two sets of
strata or layers are nearly parallel to each other, it proves that the older set
was not disturbed in its original position before the younger or later one was
deposited upon it ; but whenever the upper strata rests on the edges of those
below, these latter have been disturbed before the formation of the upper
ones took place. In the first case, where the parallelism of the strata is main-
tained, they are said to be conformable; but whenever the planes of the upper
layers rest on the edges of the lower ones, they are called unconformable.
Conformability of strata indicates a period of rest, whilst unconformability is
a certain proof of disturbance.- Any movement in the earth's crust must pro-
duce some changes in its layers or strata, resulting either in a bending or
breaking of the same, whereby fissures, folds and faults are originated. Fis-
sures are rents caused by breakage, without any displacement of the rock on
either side of the fracture, below or above their former level ; but, whenever
the masses on one side or the other have changed their positions, either by
elevation or depression, the rent becomes a fault. According to the great
difference in the magnitude of the forces producing the faults, the size of the
latter must also differ greatly. We find them measuring from an inch and
less, to many hundred feet. Faults are of great inconvenience to miners,
especially where they appear of considerable size. Folds of strata are the
result of their bending without breaking ; they differ in size from a few feet

A SKETCH OF GEOLOGY. 11

to many miles, and form, very often, extensive valleys and mountains. Strata
are very seldom found perfectly horizontal; they may be so for a short distance,
but, extending over a larger area, they will always show a certain amount of
curvature. These curves bending inward — that is, with their convexity toward
the center of earth — are forming troughs ; bending outward, they form arches.
A line running, in a series of strata, through the highest point of their arches,
is called their anticlinal axis, and the line running through the lowest \ oint of
their troughs is known as their synclinal axis. If no denudation had inter-
fered, we would always find the anticlinal axis to correspond with elevations,
and the synclinal with valleys ; but, since, by the influence of weather and
water the figuration of our earth's surface has greatly changed, we often meet
with anticlinal valleys and synclinal hills. The correct location of these lines
is often of great importance to the geologist in surveying a certain district or
country, which he can easily accomplish if he bears in mind that his proceed-
ing from older upon younger strata leads him towards the synclinal ; and vice
versa, if he proceeds from younger upon older formation he approaches an
anticlinal.

Two other important features of the stratified rocks are their dip and strike.
Upon these, to a great extent, depends the peculiar topography of the earth's
surface.

Dip is the amount of the deflection of strata from the horizontal or level
line ; it is measured by, or expressed in, degrees. If a layer has a dip of forty-
five degrees, it is bent downward, and forms with the horizontal surface an
angle of forty-five degrees. Wherever the dip increases to an angle of ninety
degrees, the strata stand on their edges in a vertical position. Strike is the
horizontal line drawn at right-angles to the direction of the dip. Rocks with
a southern or northern dip, will have an eastern or western strike. As long
as the dip of certain strata runs in the same direction, their strike is indicated
by a straight line ; but as soon as the dip changes its direction, the strike will
assume the shape of either a broken or curved line. Eocks with great dip
produce a broken undulating country, and in accordance with the curved or
straight lines of the strike, we find the hills and valleys respectively winding
or rectilineal.

PALEONTOLOGY.

Palaeontology treats of the animals and plants which inhabited our planet
during former periods, and may, therefore, be properly styled the natural
history of by -gone ages. From zoology and botany, it differs only in so far
as its objects belong mostly to an extinct fauna and flora, the remains or
traces of which are imbedded in the rocks and soils of the earth's crust. Palae-
ontology forms a science of itself ; but on account of its intimate connection
with geology, it is generally considered as only a branch of the latter. The

12 PALEONTOLOGY OF KENTUCKY.

objects with which palaeontology deals are known under the name of " fossils,"
a term designating bodies "dug out of the ground," and which was formerly
applied to metals and rocks, as well as to organic remains. At present the
word fossil is used in a more restricted sense, applying only to such geological
objects from which science may deduce information about the organic life of
the past. These objects mainly consist in remains of animals and plants, such
as shells, teeth and bones ; or stems, leaves and fruits ; but they also include
the burrows and tracks of annelids, the footprints of saurians and other ani-
mals, and even the droppings of fishes and reptiles, which are known under
the name of coprolites. Some geologists class among the fossils even objects
produced by man, such as arrow-heads, spear-heads and canoes found in the
gravel and clay beds of our fields and river shores ; but, inasmuch as they
properly belong to archaeology, they can not be counted among the fossils.

The real nature of fossils was known more than five hundred years before
the Christian era, by Xenophanes. He observed the fossil remains in the
quarries of Syracuse, consisting of marine shells and fish-bones. He recognized
them as the remains of real animals, that had lived there at the bottom, of
the sea, where they were imbedded in mud, which afterwards hardened into
the rocks then inclosing them. He also laid down the general proposition, that
the geographical features of our earth are not constant, but that, where land
now is, sea has been, and where sea now is, land has been. Afterwards this
clear conception of the real nature of fossils appears to have been lost, until
the end of the seventeenth century, when Nicholas Steno, Professor of anat-
omy in Florence, though a Dane by birth, gave them again a correct explan-
ation, and revived the theory of Xenophanes.

Before Steno, during the fourteenth, fifteenth, sixteenth and seventeenth
centuries, fossils were regarded as mere figured stones, portions of mineral
matter which have assumed the forms of leaves and shells and bones, just as
those portions of mineral matter which we call crystals, take on the form of
regular geometrical bodies. Others considered them the products of the germs
of animals and of the seeds of plants, which have, as it were, lost their way,
in the bowels of the earth, and achieved only an imperfect and abortive devel-
opment. These opinions appear to us ridiculous, and we are inclined to sneer
at our ancestors for entertaining such ideas about a matter which is now so
clear and simple. People who believed in spontaneous generation, could have
no difficulty in taking fossils for sports of nature, and we know that spon-
taneous generation was generally believed in up to the present century ; and,
even to-day, thousands of people, laying claim to a fair education, still adhere
to that belief These erroneous ideas about the nature of fossils were, long
after Steno' s correct interpretation, maintained among common people, but
men of science became more and more convinced of the correctness of

A SKETCH OF GEOLOGY. l£

Xenophanes' theory. To-day, every person who has gained an insight into
palaeontology, knows that the fossils found in most of the sedimentary rocks
are originated by animal or vegetable remains, which, became imbedded in the
mud at the bottom of the sea, during former ages. In speaking of fossils, we
generally describe them as remains of animals and of plants, which is not
in accordance with the facts, at least not for the majority of them, inasmuch
as, in the larger number, not a particle of organic matter is preserved, and
only the form of the imbedded body retained. The original animal or vege-
table substances dissolved and became replaced by calcareous, siliceous and
other minerals. The remains, therefore, underwent an active transformation
into stone, or became, as we call it, petrified. Fossils thus transformed or
changed, are classed together under the name of petrifactions.

This term is very often used as a synonym for fossils, but erroneously ;
because not every fossil has passed through a petrifying process, while there are
many belonging to younger formations, that have, outside of form and struc-
ture, retained also the color and organic matter of the original remains. Every
petrifaction is a fossil, but not every fossil is a petrifaction. The process by
which the transformation of organic remains into mineral bodies is produced,
is of a chemical nature, and depends upon conditions not yet fully under-
stood.

We must distinguish between petrifactions and incrustations, although the
latter are often classed among the former. Incrustations are generally pro-
duced in springs, whose waters are charged with a considerable amount of
calcareous matter, which settles upon immersed bodies, like flowers and
branches, or shells and bones, inclosing them with a mineral coat or crust,
but never permeating them, as is done in the case of petrifaction. By break-
ing such incrustations we find, either the inclosed bodies unchanged, or, if
they have disappeared, the place formerly occupied by them *a hollow mould.

Another transformation of animal matter is by many erroneously classed
among petrifactions. We sometimes notice in public papers reports of cases
where human bodies, resurrected after some years of interment, have been
found, not only well preserved in form, but so hard and stiff, and so much
increased in weight, as to appear completely changed into stone. Such cases
are looked upon by a great many people as a kind of miracle, while, really,
they are nothing more than the result of a chemical process by which the
animal fat has been converted into a sort of wax. Transformations of this
kind occur only in bodies buried in wet places, where they are completely
submerged by underground water charged with antiseptic ingredients. As
soon as these bodies are removed from their original resting place, they
commence to decompose, a fact clearly showing that they never underwent
the process of petrifaction. The wax-like material into which the fat is con-

14 PALEONTOLOGY OF KENTUCKY.

verted is called adipocere. It was first discovered by the French scientist
Fourcroy, in the year 1787, during the removal of the cemetery of the Inno-
cents, in Paris.

USE OF FOSSILS.

Collectors of geological and palaxmtological specimens are often objects of
wonder and curiosity to people who notice them closely examining rock-piles
and clay-banks. What are those fellows doing there ? What are they hunt-
ing for? These questions are asked, without exception, by almost every
person passing by, and if the men of science show the things they are looking
for, and explain their origin and meaning, they may consider themselves very
fortunate if, in ninety-nine out of a hundred cases, they are not looked upon as
fit recruits for a lunatic asylum. The ignorance prevailing among the mass of
the people, about objects of natural, science, and especially of geology and
palaeontology, is appalling. Such ignorance might be excused among the lower
classes, who had neither time nor opportunity to acquire knowledge, but to
find it, even at the end of the nineteenth century, among the majority of
persons who lay claim to a fair and liberal education, is very humiliating, and
proves the inefficiency of our schools, at least in that direction.

Fossils are picked up, by people in general and by curiosity hunters in
particular, because they look so "pretty" or so "strange," as the expression
may be; but that these pretty and strange-looking things are of the greatest
importance to science, and of immense service to industry, is, so far, known
only to very few, outside of the scientific world. Fossils are the letters with
which Nature has written the earth's history, in a language intelligible to
every student of natural science, whatever nationality he may claim. They
faithfully report to us the different processes and changes through which our
globe has passed * from its beginning as a solid body to the present day. In
them, the animal and vegetable kingdoms of by-gone ages arise from their
tombs, and present themselves to the investigation of science. They furnish
the indisputable proof that the organized world commenced with its lowest
forms, and developed gradually into its higher types. Mantell, an English
geologist, says of them: "Fossils have been eloquently and appropriately
termed medals of creation, for, as an accomplished numismatist, even when
the inscription of an ancient and unknown coin is illegible, can, from the half
obliterated effigy and from the style of art, determine with precision, the
people by whom, and the period when it was struck ; so, in like manner, the
geologist can decipher these natural memorials, interpret the hieroglyphics
with which they are inscribed, and, from apparently most insignificant relics,
trace the history of beings, of whom no other records are extant, and ascer-
tain the forms and habits of unknown types of organization, whose races were

A SKETCH OF GEOLOGY. 15

swept from the face of the earth long before the appearance of man and his
contemporaries." The fact that fossils show the gradual development of
organic life from its lowest to its highest types, affords to science the means
of determining the relative age of the different strata in which they are
imbedded ; rocks, for instance, embracing remains and traces of fishes, must
be younger than others in which only fossils of shells and corals are contained ;
or, again, strata only imbedding seaweeds and other low forms of the vegetable
kingdom, must be older than those in which leaves and fruits of the trees of
our present forests are found. Fossils tell us by their character, and by
their mode of preservation, whether they have lived at the bottom of the
ocean, in fresh water lakes or rivers, or on the dry land. If they lived in
the seas, they also inform us whether these were quiet or stormy, deep or
shallow. By the data deduced from fossils, geologists are able, to-day, to write
the geographies of former geological epochs, and to mark oat on maps the
exact distribution of land and water prevailing on our globe during those
periods. What the compass is to the navigator, guiding him across the
pathless ocean into the intended port, are the fossils to the geologist in his
scientific investigations, and in his explorations for economical and industrial
purposes. They not only tell him the history of the earth, and of its former
inhabitants, they also show him the fields where the gold and diamond hunter
may find those brilliant treasures with which our daughters like to heighten
and brighten their natural charms. They indicate the places where to dig suc-
cessfully for the briny water which furnishes our table with the most indis-
pensable spice, or for the valuable oil illuminating our> houses and parlors.
They also locate the mines from which we extract that invaluable mineral which
not only affords us comfort at home, but also speeds our travels across the
oceans and the plains.

Fossils are the letters in the geological alphabet. To read the latter you
must know the former. Without their thorough understanding, no successful
study of geology is possible.

GEOLOGICAL PERIODS.

During the infancy of the geological science, it was generally believed that
different periods had existed in former ages, which were separated by sharply
defined division lines, and that each period possessed its own creation ; which
meant that all the different species of animals and plants of a certain period
were created and destroyed during that period, and that, for the succeeding
epoch, an entirely new creation had to take place. This belief in the total
destruction of all existing life at the end of the different geological periods,
called cataclysm, originated from the fact that different groups of strata con-
tain different groups of fossils, and was upheld by the belief in a priori ere-

10 PALAEONTOLOGY OF KENTUCKY.

ation of each species. Corresponding with those periods, the stratified rocks
were divided into different formations.

The rapid progress of the geological science has expunged the division lines
between the periods, and has upset the theory of cataclysm. The existence of
different groups of fossils in different strata can not be denied ; but a more
careful examination of the fossils has already shown, and hereafter will show
more conclusively, that the existing differences are not the result of new cre-
ations, but are produced by the gradual modifications occurring in species
exposed to changes in their surroundings during the course of many centuries.
The theory of evolution, now generally accepted by all men of science, has
destroyed the theory of cataclysm, as well as the belief in an a priori creation
of each single species. The division of the geological time into periods, and
of the stratified rocks into formations, though based upon erroneous supposi-
tions, has proved to be of great convenience to geologists, and is, therefore,
maintained. The dividing lines, however, are not fixed by nature, but may
be shifted by arbitration. The whole geological time, from its beginning to the
present day, is divided into four great divisions called ages. These are as fol-
lows :

1. Azoic AGE, embracing the time from the beginning of the earth as a solid
body to the appearance of life in the shape of either animals or plants.

2. PAL^EOZIC AGE, beginning with the appearance of organic forms, and ter-
minating with the close of the coal formation.

3. MESOZOIC AGE, beginning at the end of the coal formation, and closing at
the appearance of mammals.

4. CENOZOIC AGE, embracing the balance of time up to the present day.
Corresponding with this division of time, we divide all the rocks into the

four groups of azoic, palaeozoic, mesozoic and cenozoic rocks, according to the
age in which their respective formation took place. The first group of rocks
is of little or no interest to the palaeontologist, inasmuch as it does not contain
any traces of life ; still, what we to-day consider ^azoic, or bare of life, may,
to-morrow, disclose forms of undoubted organic character. Not many years
ago all the metamorphic rocks were considered azoic; but since Canadian geolo-
gists have discovered the Eozoan canadense, and have also established the fact
that numerous traces of coal and graphite are to be found in these rocks, the
existence of some kind of life during the formation of that group can not be
doubted any longer. As soon as the presence of life during the formation of
those rocks, which heretofore were classed among the azoic, is definitely settled,
those rocks have either to be removed to the palaeozoic group, or, as Professor
Dawson, of Canada, has proposed, a new group, to be called the Eozoic, has to
foe established for their reception,

A SKETCH OF GEOLOGY. 17

All the different metamorphic rocks constitute together the Archaean forma-
tion, which is subdivided into the Laurentian and Huronian groups. The
Laurentian group forms the base of the whole geological column of sediment-
ary rocks. It derives its name either from the St. Lawrence river or from the
Laurentian mountains in Canada, where it is exposed over an extensive area.
In the United States we find it cropping out in New York, where it forms the
Adirondack mountains ; also in Michigan and Tennessee, and in a few other
States. Its thickness in Canada is estimated to be about six miles, or more
than 30,000 feet. About the middle of its column are the strata containing
the Eozoan canadense, the real nature of which is still involved in some doubt.
However, it appears that a majority of geologists have accepted it as the fossil
remains of a Rhizopod, and consider it as the commencing point of animal
life.

The Huronian group has received its name from Lake Huron, in the vicinity
of which it is largely developed and exposed. It overlies the rocks of the
previous group in a manner proving its later origin. The dividing line between
these two Archaean groups is not sharply drawn. The absence of fossils in
these rocks compels us to base their distinction altogether upon their litho-
logical characters, which, alone, seldom affords a safe criterion for the deter-
mination of groups. The thickness of the Huronian group in Canada is
estimated to exceed 10,000 feet. None of these Archaean rocks are exposed
in the State of Kentucky, though their presence at great depth can not be
doubted.

The rocks formed during the Palseozic age are divided into three formations :
the Silurian, the Devonian and the Carboniferous.

SILTJKIAN FORMATION. — This formation was first established by Sir E. T.
Murchison, the celebrated English geologist. He named it after the ancient
Silures, the former inhabitants of that portion of Britain where he first studied
this class of rocks. Murchison divided this formation into the Upper and
Lower Silurian, a subdivision generally accepted by the geologists of Europe
and America, and which answers fully for most purposes. The Lower Silurian
formation is the most important on account of its large extent in thickness, as
well as in area. It is subdivided into the following groups, which are given
in ascending order.

1. St. John's Group; 2. Potsdam Group; 3. Calciferous Group; 4. Quebec
Group ; 5. Chazy Group ; 6. Birdseye Limestone ; 7. Black Eiver Group
8. Trenton Group ; 9. Utica Slate ; 10. Hudson River Group. Some of these
groups, as will be seen, are named after localities where they are prominently
exposed, while others have received their name from the peculiar character
of the rocks which they embrace. Of all these different groups, the Trenton

OEOL. SUB. — 3

18 PALEONTOLOGY OF KENTUCKY.

and the Hudson River groups are of main importance to Kentucky geologists.
These two cover extensive areas of our State, and show in some places con-
siderable thickness. The balance are either wanting in Kentucky altogether,
or exposed in only very few and very limited spots.

The Hudson River Group is generally known as the Cincinnati Group, on
account of its excellent exposure at and around Cincinnati. In Kentucky, the
blue limestone of the Trenton forms the surface-rock of that rich and world-
renowned district known as the "Blue-grass Country," and is, there, the
source of the most productive soil of the United States. In consequence of
the rapid decomposition of this rock, when exposed to the influence of sun-
shine and rain, it keeps the soil in an everlasting virginity, a soil which, a
thousand years from to-day, will produce as well as it does at present, pro-
vided all other conditions remain the same. The Upper Silurian is divided
into the following groups :

1. The Oneida Conglomerate ; 2. The Medina Sandstone ; 3. The Clinton
Group ; 4. The Niagara Group ; 5. The Onondaga Salt Group ; 6. The Lower
Helderberg Group. Of these subdivisions of the Upper Silurian, only the
Clinton and the Niagara groups deserve especial notice as Kentucky forma-
tions. The Clinton Group is only found in few and isolated places, and never
attains a thickness of any consideration. The Niagara Group embraces the
same kind of rocks which form the bed of the Niagara river at its world-re-
nowned falls, whence it derives its name. In Kentucky it neither covers
extensive areas nor attains great thickness ; but it furnishes, in some places,
excellent building stone. Near Louisville, we find it well exposed in the
quarries east of the city, providing Louisville with most of the limestone
required for building purposes. Here the Niagara rocks are very rich in fos-
sils, which are mostly well preserved, and have furnished a great deal of the
material now in the valuable collections of several Louisville geologists, and
which enables science to acquire an extensive knowledge of the fauna of the
Niagara period.

DEVONIAN FORMATION.— This formation is named by Murchison after Devon-
shire, in England, where it is prominently represented in the surface-rocks.
Here in America we have subdivided it in the following groups :

1. Oriskany Sandstone ; 2. Upper Helderberg Group ; 3. Hamilton Group ;
4. Portage Group ; 5. Chemung Group; and 6. Catskill Group.

The Oriskany sandstone is placed here at the base of the Devonian column,
whilst others consider it as the youngest member of the Silurian groups. It is
extremely difficult to decide which of the two places assigned by different
geologists to the Oriskany sandstone, is the proper and correct one. If, in
accordance with the opinion of the older geologists, the Silurian period had

A SKETCH OP GEOLOGY. 19

been closed by a cataclysm, extinguishing all life of the Silurian time, Nature
itself would have drawn a dividing line between Silurian and Devonian forma-
tions which could not be misunderstood by anybody ; but no cataclysm ever
took place ; on the contrary, the transformation of the Silurian fauna and flora
into their Devonian forms was accomplished by slow and gradual modifications,
a process which did not produce partition lines, the establishment of which is
thus left to arbitration. The proper way to find out the correct position of the
Oriskany sandstone, is to carefully examine its fossils ; if these show a nearer
relationship to those of the Devonian than to the Silurian, the questionable
group belongs to the younger formation ; but if the relationship is closer to the
Silurian forms, said group should be transferred to the Silurian column. In
our own State, we find the Devonian formation represented only by the upper
Helderberg and Hamilton groups, which are so blended together that it is en-
tirely impossible to separate them from each other. Fossils characteristic of
either of these groups are found from bottom to top of the whole Devonian
columns in Kentucky. The Devonian formation does not cover a very extensive
field in our State, still it is of great importance for economic, as well as for
scientific purposes. It furnishes to the builder rock, cement and lime ; to
the farmer, a healthy and productive soil ; and to the geologist, those pre-
cious specimens of fossil corals, crinoids and shells, which nowhere on the whole
globe can be found in such abundance of specimens and species, and in such
excellent state of preservation, as at Louisville and its vicinity. The widely
known Falls of the Ohio River are not only known here in this country as an
obstruction to navigation, but they are known to geologists of the whole civil-
ized world as the great store-house where the Devonian world has collected the
choicest specimens of its animal kingdom.

The Upper Helderberg group is often called the Corniferous limestone, or the
Corniferous group, on account of the great mass of hornstone which it contains.
This hornstone is found in great abundance in all of our Devonian strata, and
it would, therefore, be advisable to designate the whole Devonian column in
Kentucky as the Corniferous group.

CARBONIFEROUS FORMATION. — This formation is divided into Subcarbonifer-
ous and Coal Measures; both are still covering a large territory in Kentucky,
though it appears that their former original extent has been greatly reduced by
denudation. At present we have two large coal fields in our State ; the eastern,
which forms a part of the Appalachian coal region, and the western, belonging
to the Illinois coal fields. Both these districts, it appears, were formerly
united, though they are at present separated from each other by a broad strip
of land whose surface-rocks belong either to the Devonian or to the Silurian.
That the Carboniferous strata originally covered this dividing strip can scarcely

20 PALEONTOLOGY OF KENTUCKY.

be doubted, when we find the many knobs by which it is covered capped with
the Carboniferous formation. Those knobs can not be the products of volcanic
action. The undisturbed horizontality of their layers proves them to be the
result of denudation. The denuding influence of heat, frost and rain appears
to be too insignificant to have produced such an amount of excavation as would
have been necessary to cut down many square miles of land from their former
to their present level — a difference in some places amounting to several hundred
feet. However, we must always bear in mind that geological agencies are
enabled to do their enormous work, not so much by their magnitude, but
mainly by their perseverance throughout the endless spaces of geological
times.

Of the Subcarboniferous we distinguish the following five subdivisions : Kin-
derhook, Burlington, Keokuk, St. Louis and Chester groups. It is doubtfu
whether the Kinderhook group is really different from the Chemung group,
and, even if a difference exists, it remains questionable where to place it prop-
erly, whether with the Devonian or the Subcarboniferous ; its fossils show a
nearer relationship to the Devonian fauna than to that of the superimposed
strata of the Subcarboniferous. In Kentucky we find only the three younger
formations, viz. ; the Keokuk, the St. Louis and the Chester, which form a
kind of border around the coal fields. The St. Louis limestone gives a peculiar
feature to the country of which it forms the surface-rock. In its strata we
find the many, often very extensive caverns, and the surface covered over
with numerous funnel-shaped sink-holes. All the formations and groups so
far enumerated, originated during the Palaeozoic Period ; they alone are of
interest to Kentucky, inasmuch as they embrace all the surface-rocks of our
State.

MESOZOIC AGE. —This produced the following three groups : Triassic, Jurassic
and Cretaceous. None of these are represented in our State, though they
cover vast areas of our continent, especially the Triassic and Cretaceous, whilst
the Jurassic is only recognized in the Rocky Mountains and on its western
slope.

CENOZOIC AGE. — During this age, which reaches to the present time, the
Tertiary formation was called into existence. In it we find the earliest repre-
sentatives of the different genera and species of animals and plants which to-
day inhabit our planet. The subdivisions of the Tertiary are Eocene, Miocene
and Pliocene.

Of living or recent species, the Eocene contains 3 to 4 per cent. ; the Miocene
from 18 to 20 per cent., and the Pliocene from 35 to 95 per cent, according to
Ly ell's definition of these different groups.

In the localities where Lyell studied these different rocks, there was a clear

A SKETCH OF GEOLOGY. 21

line of demarkation between the groups as he organized them, and in each
group he found the above stated percentage of recent species ; but other locali-
ties of Tertiary rocks showed more than 4 and less than 18 per cent. , and others
again more than 20 and less than 35 per cent, of living species among their
fossils. The question there and then arose, to which of the groups such strata
should be attached ? This question is solved by placing them in those groups
with which their fossils show the nearest relationship.

MOLLUSCA.

Mollusca form one of the great animal sub-kingdoms ; their name is derived
from the Latin word "Mollis," meaning soft, on account of the soft consistency
of their body. This name was given to them by the French savant, Cuvier.
This sub -kingdom embraces the Mollusca proper and the Molluscoids. The
latter include the Polyzoa or Bryozoa and the Ascidians. The Ascidians hav-
ing no shell, but instead only a kind of leathery sack, are not, so far, found in
a fossil condition. The Bryozoa were formerly classed with the Corals on
account of the resemblance of their calcareous support with those forms, but
a closer study of the animals themselves proves their nearer relationship with
the Mollusca. Inasmuch as the following monograph only treats of the fossil
remains of the Mollusca proper, I deem it sufficient to limit my description to
the latter.

The soft condition of the animals of this class makes it necessary to provide
them with, a protection in some shape or form. This is given them either by a
calcareous envelope called their shell, or by a leathery sack or mantle surround-
ing the body. This mantle is possessed by every Mollusca, whether it is pro-
vided with a shell or not; but the mantle of those without shell is more
leathery and better adapted for protection than the mantle of the shell-bearers.
The shells are either of one, two or several pieces, and are accordingly called
univalves, bivalves and multivalves. The common garden snail belongs to the
first, the river mussel to the second, and the Chitons to the last group. Some
of the Mollusca have a regular head furnished with eyes, tentacles, and a mouth
with jaws and teeth. This class is called Encephala. The balance, having no
head, are known as Acephala. The first group is divided into Cephalopoda,
Gasteropoda and Pteropoda; the second into Brachiopoda and Lamellibran-
chiata.

CEPHALOPODA, meaning head-footed, so named because their arms or feet are
arranged around their mouth. To this class belong the Nautilus, the Argo-
naut and the cuttle-fish of the present fauna, and the Ammonites, Cereatites
and Belemnites of former ages. The bodies of most of them are symmetrical,
that is, both halves of their bodies are identical in parts and size; their loco-

22 PALEONTOLOGY OF KENTUCKY.

motion is produced either by the muscular feet surrounding their mouths, or
by two fins attached to the sides of their body, or, again, by the forcible ex-
pulsion of water through a tube, called the siphon. There are two orders of
Cephalopods : Dibranchiata and Tetrabranchiata, the first possessing two and
the second four branchiae.

The first order includes the cuttle-fishes ; they are all naked, with the ex-
ception of the Argonaut. Their soft body is supported by an internal shell.
Plate I, figure 12, shows the complete animal of the Sepia officinalis ; and Plate
I, figure 16, is a Belemnite, or the internal shell of one of the dibranchiate
Cephalopods. Most all the species of this order are provided with an ink-bag,
the contents of which they discharge when pursued by their enemies. Of the
second order, the Tetrabranchiata, only very few species are living at the pres-
ent time. Plate I, figure 24, shows the Nautilus pompilius, the main repre-
sentative of the tetrabranchiate Cephalopods of the present seas. The oceans
of former ages were swarming with species of this order, fossil forms of which
are figured on Plate I, figures 1, 2, 18 and 19. Their shells are internally
divided into cells or chambers (see Plate I, figures 1 and 24), by a series of
partitions called the septa (see Plate I, figure 245), connected by a tube called
the siphon or siphuncle, shown by c, Plate I, figure 24. Only the last chamber,
called the body-chamber, is occupied by the animal, while the others are empty
and serve as air-chambers. In fossil specimens very often the outer shell is
removed, and the edges of the septa are seen (Plate I, figures 18 and 19),
which are called sutures. Their form serves to distinguish different genera ;
they are curved in Nautilus and Orthoceras, zigzag in Goniotites, or foliaceous
in Ammonite.

The siphuncle is also of great importance in determining genera ; its shape
and location have to be noticed by the student of Palaeontology. Its shape is
so variable that it is impossible to give here a sufficient explanation of the
same, whilst its siphuncle may be located either in the center of the shell or
in its dorsal or ventral lines, or even on either of its sides. The opening of
the body-chamber is called its aperture, which, in different species and genera,
assume different shapes, and is generally closed by a calcareous plate, called
the operculum.

GASTEROPODA. — This class includes land and water-snails, which are either
naked or provided with a shell. They received their name because their loco-
motion is accomplished by the lower part of their body, which is provided
with strong muscles, and, by its contractions and expansions, serves them as a
foot. (See Plate I, figure 13.) Their shells are generally univalve, either
spiral or tubular, but a few are multivalve, the Chitons (see Plate I, figure 11).
In the spiral shells we have to notice the following parts : see Plate I, figure

A SKETCH OF GEOLOGY. 23

2, a, the apex ; C, c and d, sutures ; a to f, the spire ; g, the aperture. In
figure 14 of the same plate, "a" is the posterior canal, "C" the anterior canal,
and "d" the outer lip of the aperture. Each full turn of the spiral is called a
whorl. The axis (see Plate I, figure 23), ("a"), around which the whorls are
coiled, is either solid or it is hollow, as may be seen in Plate I, figure 10. In
this case the shell is called perforated or umbellicated. Nearly all the shells
are dextral, or right-handed ; others are sinistral, or left-handed ; see Plate I,
figures 14 and 15. The first is dextral, the second sinistral. In a few species
the shell is regularly sinistral ; for instance, in Clausilia, while among those
with dextral spires, sometimes sinistral aberrations are found. The last turn
of the shell is called the body- whorl, and the aperture is generally closed by
an operculum.

The aperture is either entire, as in Plate I, figures 10 and 21, or drawn out
or produced into a canal, see Plate I, figures 14 and 15. Species having shells
with an entire aperture, are generally vegetable feeders, whilst, on the other
hand, the siphonated shells belong to carnivorous families. The Gasteropoda
are found all over the world on land, in rivers and fresh- water lakes, and in
the different oceans. Their fossil representatives run through all the different
geological strata, from the lowest Silurian up to recent formation of the
Pliocene.

PTEROPODA. — (Wing-footed.) Their locomotion is accomplished by means
of a pair of large fins attached to the sides of their head (see Plate I, figure 4).
Their shells are univalve, but of very different forms. Plate I, figure 5, shows
the fossil shell of one genera of Pteropoda, a Conularia. Animals of this class
are very abundant in all our oceans, and furnish food for a good many inhabi-
tants of the sea. In former ages they lived in all the oceans from the Silurian
age to those just preceding the now existing ones.

BRACHIOPODA. — The Brachiopoda are bivalve shell-fish, which differ from
the ordinary mussels, cockles, etc., in being always equal sided, but never
quite equal-valve. Their forms are symmetrical, and so commonly resemble
antique lamps that they were called lampades, or lamp shells, by the old natu-
ralists. The hole which, in a lamp, admits the wick, serves, in the shell, for
the passage of the pedicle by which it is attached to submarine objects. The
valves of the Brachiopoda are respectively dorsal and ventral. The ventral
valve is usually the larger, and has a prominent beak, by which it is attached
or through which the organ of adhesion, the pedicle, passes. The valves are
articulated by two curved teeth in the ventral valve, which are received by
sockets of the dorsal valve ; some genera and species are not provided with such
hinges. In both the articulated and unarticulated Brachiopods, the valves are
opened and closed by strong muscles, whose places of attachment are seen in

24 PALEONTOLOGY OF KENTUCKY.

Plate I, figure 25. Among the fossil shells of even the older Palaeozoic strata,
we find sometimes Brachiopod shells so well preserved that even the valves
may be opened as far as the teeth and sockets of the hinge will allow. Most
of the shells of Brachiopods have a peculiar structure, consisting of flattened
prisms of considerable length, arranged parallel to each other with great regu-
larity, and obliquely to the surfaces of the shell, which is also perforated by
canals (see Plate I, figure 22). This great class of Mollusca has derived its
name from the two long ciliated arms developed from the sides of the mouth,
with which each animal is provided as means to create currents which bring
to it its food. These arms (Plate I, figure 9) were considered by former natu
ralists as instruments of locomotion ; but it is now ascertained that they, out-
side of their first mentioned purpose, serve mainly as breathing organs ; the
erroneous name Brachiopoda (arm-footed), should, therefore, be corrected into
Brachionabranchia (arm-breathers). Most of the Brachiopoda are provided
with an internal skeleton, consisting of two spiral processes in the Spiriferirhe
(see Plate I, figures 7 and 8), whilst in others, the Terebratula and Thecidin,
this skeleton takes the form of a loop, as seen in Plate I, figures 6 and 26.
This skeleton serves as a support for the brachial membrane. The prominent
parts of the Brachiopod shell are the following : Dorsal valve, the upper one,
which is usually the smaller, ventral valve, the lower one, which is generally
the larger. The beak is that portion of the valve which terminates above the
hinge -line in a sharp point or in a perforation (as seen in Plate I, figure 25
"a5'). This perforation is called the foramen. The most convex portion of
the valve near the beak is known as the umbo. Most of the shells have below
the beak a triangular opening, which, in valves without hinge line, is closed
by a separate body, consisting of either one or two pieces, the deltidium. In
shells with a hinge area, as the Spirifera and Cyrtina, said area is divided in
two by the triangular opening, which is partly or entirely closed by the growth
of the shell. This is known as the pseudo- deltidium. In some shells the
outline of the valve forms on both sides of the hinge a straight line, the hinge
line, which may be as long as the greatest breadth of the shell, or may be so
short as scarcely to be noticeable. The area which sometimes exists between
hinge-line and beak is the hinge -area, best developed in the shells of Cyrtina.
The hinge-area may be straight or curved, and is always divided by the pseudo -
deltidium.

The valves of a shell are either both convex, or one convex and the other
plane, or one convex and the other concave. In some shells, as in Spirifera,
the ventral valve has a strong depression extending and enlarging from the
beak to the front, dividing the valve into two equal halves. This depression is
known as the mesial sinus. Corresponding with this mesial sinus is an eleva-
tion in the dorsal valve, extending and enlarging also from beak to front, and

A SKETCH OF GEOLOGY. 25

called the mesial fold. Cardinal area is a synonym for hinge -area, and cardi-
nal extremities are the extreme points of the hinge-line. Of all the Mollusca,
the Brachiopoda enjoy the greatest range both of climate and depth and time ;
they are found in tropical and polar seas. The living species prefer the deep
waters to shallow lakes, though some of them are found even here. Of the
population of the seas of former ages, they formed a very large part. Their fos-
sil remains are found in almost every strata of the whole geological column.
They are not only very abundant, but also well preserved, and form the princi-
pal treasures of many palaeontological collections.

LAMELLIBRANCHIATA. — The Mollusca of this class are familiar to every one ;
they are represented by the oysters, mussels and cockles. The animal is
without head, and the shell is bivalve. The valves are attached to the sides
of the animal. We have, therefore, in this class, a right and left valve. Plate
I, figures 3 and 20, show the left valves. In figure 17, the upper valve is a right
one, and the lower a left one. The mouth of the animal is generally directed
towards the shorter slope of the shell. The hinge is on the back of the animal
and formed by teeth and sockets, together with an elastic ligament. The shells
are closed by powerful adductor muscles, but open when the animal relaxes
the muscles, or when it is dead. We distinguish in the shells of this class the
dorsal, ventral, anterior, and posterior margins. The dorsal margin contains
the hinge, whilst the ventral margin is opposite to this. The anterior margin
forms the end of the shell on the shorter slope, and the posterior margin the
end of the longer slope.

Plate I, figure 3, is the left valve of Cytherea dione, separate from Cyth-
erea, with the following prominent parts : h, the hinge ligament ; d, the umbo ;
f, the lunule ; c, cardinal tooth ; tt, lateral teeth ; a, anterior adductor muscle ,-
a, posterior adductor muscle ; p, pallial impression ; s,- sinus, occupied by re-
tractor of the siphons. The line designated as pallial impression, which in
many shells is prominently marked, indicates the place where the mantle is
attached to the shell. The presence of a bay or sinus (s), in the line of the
pallial impression, proves the animal to have possessed retractile siphons.
All the Mollusca belonging to this class live in the water, in rivers, lakes and
oceans. They are abundant at the present time, and have been so in all the
seas of former ages. Their fossil remains are often extremely well preserved,
and add greatly to the beauty of many Palaeozoic collections.

Within the here described five classes, the different Mollusca are divided into
families, genera and species. The naturalists of former centuries were able to
give a more precise definition of these terms. They believed that each species
was a priori created, and thus by sharply defined lines of distinction, separated
from all the other forms, and only related to some of these by accidental sitni-

GKOL. SUR. — 4

26 PALAEONTOLOGY OF KENTUCKY.

larity in certain features. Inasmuch as relation between organic beings
depends upon their origin from common ancestors, no real relation could
exist outside of a species among the animals and plants, if the former belief
in the stability of species had remained. The erroneous views of the old school
were based upon observations among the more highly developed animals and
plants, where the division lines between the species are more pronounced.

Had the scientists of olden times directed their investigation to the lower
organisms, they would soon have met with difficulties, and in many cases even
with impossibilities, to accomplish a specific differentiation . The evolution
theory has upset the views of the old school. It does not believe in a separate
original creation for every species, but, according to it, new ones are produced
by gradual modifications of old forms. Changes in organisms may be either
temporary, that is, dying out with the same specimen in which they first occur,
or they may be constant, when they reappear in all the succeeding generations.
Only these constant alterations will lead towards new species, and in order to
do this, they must intensify in every succeeding specimen, until they become
so characteristic as to afford an easy and sure distinction between the original
and the new species. It is obvious that this procedure in the creation of
species will leave some specimens in a doubtful position ; their modifications
may separate them from the old forms and still be insufficient to place them
among the new ones. These forms are connecting links, and serve to establish
a general relationship in larger groups of organism ; but they cause consider-
able trouble as far as classification is concerned.

It is impossible to state the exact amount of similarity required between
two animals or two plants, which will place them both either in the same
family, the same genus, or the same species. In recent years a real mania has
sprung up among some naturalists to manufacture as many genera and species
as possible. By such proceedings science is not benefited, but only becomes
incumbered with synonyms, of which, sooner or later, it has to be purged.
Such a cleaning process will be necessary in Palaeontology. This science,
which has lately passed its childhood, and which handled material, the charac-
ter of which was little known, has certainly established species and genera
which will require revision. We find, for instance, of some fossil shells speci
mens showing the outside shell with all the markings well preserved, and
again, others in the condition of internal casts, with all the shell exfoliated
between such specimens exist differences rendering it impossible to recognize
their intimate relation without closer investigation. That the first geologists,
noticing these two different forms, described them as different species, is quite
natural ; but as soon as material of this kind increased, some forms were found,
showing partly the internal cast and partly the exterior shell, combining the
two fossils which were so far considered as different species. Again, we have

A SKETCH OF GEOLOGY. 27

certain species in which the extreme forms are so different irom each other
that any one finding only these two extremes, would be fully justified in de-
scribing them as different species, but increased material furnishes intermediate
forms connecting those extremes into one species.

Before closing these introductory remarks, I will copy from an English writer
some observations which show the beneficial influence of the cultivation of
natural sciences upon the minds and morals of the people, words which should
be well remembered by every parent looking to the welfare of his child ; by
every teacher aiming by his labors to ennoble the mind and character of his
students ; and by every trustee of schools endeavoring to elevate those institu-
tions to real nurseries of the highest type of civilization. He remarks: "It is
fearfully true, that nine-tenths of the immorality which pervades the better
classes of society, originate from the want of an interesting occupation to fill
up their vacant time ; and as the study of natural sciences is as attractive as it
is beneficial, it must necessarily exert a moral and even religious influence upon
the young and inquiring mind. The youth who is fond of scientific pursuits
will not enter into revelry, for frivolous or vicious excitement will have no fas-
cinations for him. The overflowing cup, the unmeaning or dishonest game, will
not entice him. If any one doubts the beneficial influence of these studies on
the morals and character, I would ask him to point out the immoral young
man who is devotedly attached to any branch of natural science. I never
knew such an one, and if there are any, they are rare exceptions ; and the
loud clamors which are always raised against the man of science who errs,
prove how rarely the study of the works of nature fails to exert an ennobling
effect upon a well regulated mind. Fortunate, indeed, are the youth of either
sex, who early imbibe a taste for natural knowledge, and whose predilections
are not thwarted by injudicious friends."

These remarks, based upon indisputable facts, show that the value of the
natural sciences ought not to be estimated only by their financial result,
which is, unfortunately, the only scale with which most people nowadays
measure, but also, and more deservedly so, by their ennobling influence upon
the hearts and brains of the human race.

FOSSIL SHELLS

OP THE

SILURIAN AND DEVONIAN ROCKS.

BY

HENRY NETTELROTH.

II.

DESCRIPTION OF SPECIES.

OF THE

SILURIAN AND DEVONIAN ROCKS,

COELENTERATA.

SPONGIA.
Genus Brachiospongia. Marsh.

Described by Marsh in Am. Journal of Scie. and Arts., 2d series. Vol. 44, 1807 — Etymology: brachium,

an arm; spongia a sponge.

Brachiospongia digitata. OWEN

Plate XXXV., figure 3, and Plate XXXVI., figures 1 and 3.
Scyphia digitata, Owen. First Ky. Geol. Kep., Vol. II., p. Ill — 1857.

This fossil is very peculiar and very interesting ; Prof. D. D. Owen, who
described it in his Kentucky Report, placed it in the genus Scyphia of
Schweigg, but its proper place is in the later established genus Brachiospongia
of Marsh. It consists of a circular or elliptical central body, which is hollow,
and has on its lower side an elliptical aperture occupying about one-third
of the lower surface. This aperture is surrounded by an elevated thick brim,
which rises in the specimen before me more than an inch and a quarter above
the general surface; its greater diameter measures four and its smaller two
inches and a quarter. From the circumference of the central body radiate in
my shell twelve large, cylindrical, geniculated tubes, while in fossils seen by
Prof. Owen he counted only from eight to eleven. These tubes start from the
periphery with a downward direction for about a little more than an inch,
where they make an abrupt turn of about ninety degrees upwards, to the ex-
tent of more than three inches. If the interspaces between the tubes were
closed, the fossil would form a medium sized basin or bowl, with an elevated
center. The tubes are all of about the same size and shape ; all have an aper-
ture on top, which is different in shape ; in some the opening is elliptical, while
in others, it extends to the knee ; but there is no doubt that, in original speci-
mens, the aperture was limited to the top, and the lateral enlargement of the

£6 PALAEONTOLOGY OF KENTUCKY.

opening is due to wear and rubbing in its fossil condition. The internal
structure is destroyed, and only the outline or general form preserved. The
central body measures six inches in diameter, while the circle, formed by the
tops of the tubes, has a diameter of nine inches.

Formation and. Locality. — This interesting fossil is limited to one locality; it is found in the lower
strata of the Cincinnati or Hudson Kiver group, at Bright's Mill, on Benson Creek, a few miles west of
Frankfort, Ky., where, altogether, not more than about a dozen fcir specimens have been found, while
ractional specimens are more numerous.

MOLLUSCA.

BRYOZOA.
Genus Ptilodictya. Lonsdaie.

Ptilodictya, Lonsdaie. Murch. Sil. Syst. — 1839.
Etymology : ptilon, a wing ; dictyon, a net.
The correct orthography would be Ptilodictyon.

Fronds simple or branched, springing from a pointed or wedge-shaped, sub-
solid, and finely striated base or articulating process, which fitted loosely in
the socket of the expanded and firmly attached base. The free portion of the
zoarium is two-edged, with the transverse or cross section acutely elliptical,
with the surface either smooth, montiferous, or marked by transverse ridges,
and composed of two equal but distinct sides ; each side is provided with a
delicate epithacal membrane, from which the cells rise to open on the two
opposite faces of the frond. Cells quadrate, rhomboidal, or hexagonal, and
arranged in longitudinal series, or in a quincuncial manner ; pseudo-septa are
frequently present ; the walls are pierced in many species by connecting fora-
mina. The interstitial cells are usually absent ; but in the nodose species the
summits of the monticules are often occupied by smaller cells than the aver-
age. In the robust species the tubes are crossed by diaphragms placed upon
the same level in contiguous tubes.

Ptilodictya hilli. JAMES.

Plate XXX V., figures 1, 2, 4 and 5.
Ptilodictya hilli, James. Cin. Journ. of Nat. Hist., Vol. V., pt. 3, plate 7, figure 7., no descpt. — 1882.

Zoarium digitate, the number of prongs not known ; the specimen before me
shows one complete branch, which deflects from the original stem, just above
the wedge-shaped articulating process, out of the sharp edge, and extending
in the same plane with the main stem. On one of the broad sides of the
main stem, and in its center line, are two protuberances, the one opposite

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. a I

the center line of the deflecting branch, and the other about one-fourth of
an inch above it, which appear to be the buds of two new branches, but
whose positions make it somewhat doubtful, inasmuch as those new stems
would leave the plane of the two existing prongs. In similar species, as
P. ramosa and P. briareus, the branches start always from the sharp edge,
and I do not doubt that the same is the case with P. hilli. We may,
therefore, assume, that very few branches are formed. This species is gen-
erally found in more or less straight, thin strips, of different width, the
cross sections of which are either acutely elliptical or elliptic-lanceolate. Both
sides are entirely equal; they are most convex in their central line, from where
they slope in a regular but gentle curve to the lateral margins, where the sur-
faces of both sides meet at a very acute angle. The surfaces of both sides are
covered by transverse, sharply angular ridges, with interspaces of about twice
their own width. Some of these plications cross the branches from one edge
to the other in a straight line, rectangular with the margin, the course of
others is somewhat oblique, and others again cross the surface only partly.
These shorter ribs are always intercalated, and never produced by bifurcation.
The whole zoarium is covered by closely arranged rhomboidal cells of about
equal size, the walls of which form nearly straight lines, crossing each other
obliquely. The largest specimen in my possession measures nearly four
inches in length, -by more than an inch in width ; in its whole extent it does
not show any branch ; it has thirteen transverse ribs in the space of an inch.
A smaller specimen measures one inch and three- eighths in length, by one-
fourth of an inch in width, with nineteen cross ribs in the space of an inch.

Formation and Locality.— This species is named after Dr. O. O. Hill, formerly of Cincinnati, Ohio,
who first discovered it. It was afterwards found rather abundantly in the upper strata of the Hudson
Kiver group at Danville, Ky., by Prof. Linney, of the Kentucky Geological Survey.

MOLLUSCA.
BRACHIOPODA.
Genus Crania. KetziU8.

Crania. Ketzius. Schrift der Berliner Gesellschaffc Nat. Freunde. 1781. Etymology: Kranion

the upper part of the skull.

Shell smooth or -striated by radiating striae ; umbo of the dorsal valve sub-
central ; umbo of the ventral valve sub-central, marginal or prominent and
cap-like, with an obscure triangular area traversed by a central line. Shell
usually attached to other shells or marine bodies. The large muscular impres,-

32 PALAEONTOLOGY OF KENTUCKY.

sions of the attached valve are sometimes convex, in other species, deeply
excavated ; those of the upper valve are usually convex. In C. tripartita of
Minister, the nasal process divides the fixed valve into three cells. Some of
the species are either entirely free or but slightly attached. Crania craniolaris
is the type of the genus, which extends from the Lower Silurian to the present
day.

Crania bordeni. HALL AND WHITFIKLD.

Plate II., Pig. 14.

Crania bordeni, H. & W. 24th Regent's Report, p. 187—1872.
Crania bordeni, H. & W. 27th Regent's Report, pi. 9—1875.

Shell depressed conical, about half as high as wide ; beak sub-central,
slightly nearer the anterior end. Surface marked by fine radiating striae,
and somewhat strong lines of growth, giving a rugose character to surface,
especially toward the margin. This species resembles Crania crenistria, from
the Hamilton group of New York, but that species is more coarsely striated
than our shell.

Formation and Locality. Found in the rotten hornstone and in the cherty layers on top of the
hydraulic limestone of the Devonian formation in Jefferson county, Kentucky, and in Clark county, In-
diana. The quarries for hydraulic cement rock at Watson's Station, on the Ohio and Mississippi Railroad,
furnished the fine specimen of Modiomorpha concentrica, to which two fine individuals of Crania bordeni
are attached.

Genus Discina.

Lamarck.

Lamarck. Hist. Nat. des Animaux sans vertebres. 1819. Etymology: discus, a flat
round plate; the termination inui implying resemblance.

The following are some of the exterior characters of the shells of this genus,
as given by Mr. Davidson: "Circular, longitudinally and transversely oval.
Upper or dorsal valve conical, patelliform, with apex inclining towards the
anterior margin. Lower or ventral valve opercular, flat or partly convex, and
perforated by a narrow oval longitudinal slit, reaching to near the posterior
margin, and placed in the middle of an oval depressed disk. Surface smooth,
ornamented by numerous striae, radiating from the apex to the margin, or by
concentric lines of growth produced in foliaceous expansions. Shell structure
horny, and perforated by minute tubuli."

Discina doria. HALL.

Discina doria, Hall. Pal. N. Y., Vol. IV., page 19—1867.

Shell very small, sub-circular or oblate, the transverse diameter usually the
greater, but in some specimens it is reverse. Dorsal valve moderately convex,

FOSSILS OP THE SILURIAN AND DEVONIAN BOOKS. 33

apex elevated sub-terminal. Ventral valve flat or concave, the apex excentric ;
foramen comparatively large, oval, with margins depressed. The shell itself is
very thin.

The surface is marked by fine, closely arranged concentric striae, which are
plainly visible on our specimens, though they are internal casts, and entirely
silicified.

This species closely resembles the D. newberry, from Cuyahoga Falls, Ohio;
but that shell is somewhat thicker and stronger, with the apex of the dorsal
valve more elevated, and the shell is altogether larger than our specimens.
One of the specimens before me measures three lines and a half in length, by
three lines in width, and its elevation about one line.

Formation and Locality. — The specimens of this species are adhering to other fossils, a fact which
would make their identity with Discina doubtful, if not both valves were found so attached. The speci-
men* before me, three in number, occupy the valve of a Spir. oweni, and were found in the Devonian rocks
of Clark county, Indiana.

Discina grandis. VANUXEM.

Plate III., Figure 3.

Orbicula grandis, Vanuxem. Geol. Kep. 3d dist — 1842.
Discinv grandis, Hall. Pal. N. Y., Vol. IV., p. 7—1867,
Discina grandis, H. & W. 24th Reg. Eeport, p. 187—1872.
Discina grandis, H. & W. 27th Keg. Rep., pi. 9—1875.

General form broadly and transversely elliptical ; either plano-convex or
concavo-convex. Dorsal valve sometimes extremely elevated ; apex sub-central,
a little on one side of the transverse axis. Ventral valve usually moderately
concave ; foramen reaching from the center or near the center towards one side,
but varying somewhat in different individuals. Surface is marked by fine con-
centric striae, crowded near the center, and more distant and sharply elevated
towards the margin. This species is easily recognized by its larger size, and
in the ventral valve by the direction of the foramen being in the shorter diam-
eter of the shell. This valve is somewhat unequally concave, and, on the side
of the foramen, often a little convex. The specimen here described and figured,
has diameters of fourteen and twelve lines, and a height of six lines and one-
half, it may be considered as of average size among the shells found here.

Formation and Locality. This species is often met with in our rocks, but only the dorsal valve Is
preserved, it is always entirely silicified, and occurs in the cherty layers, superimposed upon the hydraulic
limestone of the Devonian formation, in Jefferson county, Kentucky, and in Clark county, Indiana. All
my specimensof this species I found in the cement quarries at Watson's Station, on the Ohio and Missis-
sippi Railroad, where the chert beds come near the surface.
GEOL. SUB. — 5

34 PALAEONTOLOGY OF KENTUCKY.

Brugmere.
Bruguiere. Encycl. Meth.— 1792. Etymology : lingula, a little tongue.

Shell oblong, compressed, sub-equivalve, attached by a pedicle passing out
between the valves. Shell structure minutely tubular, texture horny. Shell
slightly gaping at each end, truncated in front, rather pointed at the um-
bones ; dorsal valve rather shorter, with a thickened hinge-margin and a raised
central ridge inside. (Woodward.)

Lingula triangulata. n. sp.

Plate XXVI., Figure 1.

Shell of medium size ; sub-triangular or broadly sub-ovate. The lateral
margins form, at the apex, an angle of about sixty degrees ; the sides slope
from apex to two-thirds of the length of shell in a straight line ; from there
they curve gently to basal margin, which is broadly rounded. Shell is mod-
erately convex from beak down to front, but depressed almost flat at margins.
The greatest width is about one-third of length of shell from the front ; width
is smaller than length. The specimen before me measures twelve lines in
length by ten lines in width. Shell itself is thick. The surface is marked by
fine concentric lines of growth, and also by fine radiating striae, both of which
are somewhat obscure on account of exfoliated condition of fossils, which are
mostly internal casts. It appears to have some resemblance with Lingula
paliformis of the Hamilton group, but differs from it by its shape and sur-
face-markings.

Formation and Locality. Found in the Hydraulic limestone of the Devonian formation at the Falls
of the Ohio, in Kentucky.

GenUS OrtMS. Dalman.

Orthis, Dalman. Kongl. Vet. Acad. Handl.— 1817.

Etymology: Orthis, straight, in allusion to the straight hinge line.

Shell variable in shape, sub- circular or quadrate ; valves equally or unequally
convex, socket valve sometimes slightly concave, with or without a mesial fold
or sinus ; hinge line straight, generally shorter than width of shell. Both
valves furnished with an area, divided by an open, triangular fissure for pas-
sage of the pedicle. Beaks more or less incurved, that of larger valve gener-
ally more produced. Surface smooth, striated, or ornamented by single,
bifurcated, or intercalated ribs. Structure minutely or largely punctate.
Valves articulating by means of teeth and sockets.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 35

In interior of ventral valve the vertical dental plates form the walls of
the fissure, and extend from beak to bottom of shell ; between these a small
rounded mesial ridge divides the 'muscular scars, which extend over two elon-
gated depressions, margined on their outer side by the prolonged bases of the
dental plates. The cardinal muscles appear to have occupied greater portion
of anterior division of these two depressions ; the pedicle muscles occupying
the external and posterior part of same space.

The adductor was probably attached to each side and close to mesial ridge.
In the socket valve the fissure is partly or entirely occupied by a more or
less produced simple shelly process, to which were affixed the cardinal muscular
fibres, the inner socket walls are considerably prolonged into cavity of the
shell, under shape of projecting laminae, to the extremity of which free, fleshy,
spiral arms may, perhaps, have been affixed. Under this shelly process a
longitudinal ridge separates the quadruple impressions of the adductor, which
on each side forms two deep oval depressions, placed obliquely one above the
other, and separated by lateral ridges, branching from the center one. The
genus Orthis is very nearly related to Strophomena, from which the more
typical forms may in general be easily separated by their usually greater con-
vexity, and the rounder and shorter hinge-line.

Orthis biforata. Schiotheim.

Plate XXIX., figures 18 to 22.

Terebratulites biforatus, Schiotheim, Petrefact. P. 265 — 1820
Orthis biforata, Meek. Pal. of Ohio, Vol. I., p. 112—1873.
See the list of synonyms in last cited Report.

Shell small, transversely oval-subquadrate, moderately convex, wider than
long ; hinge-line a little less than the greatest width of the shell ; cardinal
angles obtuse, seldom rounded. Surface plicate.

Ventral valve depressed convex ; mesial sinus well defined from beak to
front, deep, with flattened bottom, containing four plications, the central ones
starting from the beak, while the lateral start about the middle of valve from
marginal slopes of the sinus.

In one of my specimens one of the lateral plications within the sinus is
wanting; beak a little more elevated, and somewhat stronger than that of
the opposite valve, only faintly curved, almost straight ; cardinal area narrow,
but increasing in height towards beak ; foramen almost an equilateral tri-
angle.

Dorsal valve generally a little more convex than other, greatest convexity
at the umbo, from where it curves gently and regularly to lateral and front
margins.

36 PALAEONTOLOGY OF KENTUCKY.

Mesial fold prominent and well-defined from beak to front, somewhat flat-
tened on top, bearing five plications in its lower half. In younger specimens
the fold has only three plications, of which in older individuals the lateral ones
dichostomize at about the middle of shell, and thus form the five costae of
the lower part. The umbo is more, and the beak less prominent than that of
the other valve; hinge-area also somewhat smaller than the ventral. Size of
shell variable, the largest specimen in my collection, figured on plate XXIX.,
sub-figures 18, 19 and 20, has a width of seven-eighths of an inch, a length of
five-eighths of an inch, by a depth of three-eighths of an inch.

Surface marked by from five to seven strong angular plications, counted at
the margins, some of which are formed by bifurcation. No other surface-mark-
ings are visible.

Formation and Locality. — Pound in the lower strata of the Niagara formation in the quarries east of
Louisville, Ky. This species is very common and of larger forms in the Lower Silurian, but to find its
representatives in the Niagara rocks is somewhat of a surprise. They are rather belated stragglers.

Orthis borealis. BILLINGS.

Plate XXXIV., figures 14 to 20.

Orthis borealis. Billings. Can. Nat., Vol. IV., p. 436—1859.
Orthis frankfortensis, James. Cat. Low. Sill. Foss., Gin. gr., p. 10 — 1871.
Orthis borealis, Meek. Pal. of Ohio, Vol. I, p. 101., pi. 8—1873

Shell of rather less than medium size, transversely oval-sub-quadrate, or
truncato-sub-oval, the length and breadth varying with relation to each other
from 9 to 11, to 11 to 12 ; both valves convex ; hinge-line generally less than
the greatest width of the shell, and meeting the lateral margins under a more
or less obtuse angle ; lateral margins, from cardinal extremities to base, form-
ing a compound, reversed curve of regular form, concave at the cardinal angles
and thence convex to base, which is broadly rounded, but sometimes showing
also a faint sinuosity. Ventral valve most convex near umbo, sloping from
there somewhat abruptly, but in a gentle curve to posteriolateral margins, while
the anterior central region is depressed so as to form a broad, very shallow
mesial sinus which extends backwards to middle of shell ; beak more prominent
than that of the other valve, sharply pointed, inclined backward and slightly
arched ; cardinal area broad-triangular, well defined by angular margins, and
concave ; foramen rather narrow, its height exceeding its base. Dorsal valve
sometimes more convex than the other; its greatest convexity a little above
the middle of the valve, from where it slopes in gentle curves to lateral and
antwior margins ; the central-anterior portion of the valve is slightly elevated,
forming a broad, low, and undefined mesial fold, whose starting point is at, or
somewhat in front of middle of valve ; beak of medium size, arched, but not

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 37

incurved; cardinal area of about half the height of the ventral, and slightly
curved. Surface of both valves ornamented by distinct, rather prominent,
radiating ribs, of which from thirty-six to forty-four may be counted on the
margins of shell, most all of which extend from beak to front, Bifurcation
is very seldom noticed, and then only in old and very large specimens. With
the exception of a few imbricating lines of growth, no other surface-markings
are visible. This species resembles Orthis plicatella, but is more convex, and
has more numerous and smaller costae ; it is also less transverse, and its mesial
depression and elevation are more marked.

Formation and Locality. — Found at Frankfort, Ky., in the Trenton limestone, in great abundance,
and in excellently preserved specimens.

Orthis elegant ula. DALMAN.

Plate XXXII., figures 62 to 57.

Orthis elegantula, Dalman. K. Vet. Acad. Handl., p. 117 — 1827.
Orthis canalis, Sowerby. Murch. Sil. Syst.. p. 631 — 1839.
Orthis canalis, Hall. Geol. Rep. 4th dist. N. Y., p. 107—1843.
Orthis elegantula, Hall. Pal. N. Y., Vol. III., p. 252—1852.
Orthis elegantula, Hall, llth Kep. of Indiana, p. 285—1881.

Shell small, semi- oval, plano-convex, sometimes even somewhat concavo-
convex ; length usually exceeding width. Hinge-line less than greatest width
of shell, cardinal extremities rounded.

Ventral valve gibbous, greatest convexity about the middle of the valve,
from where it slopes in regular curves gently to front, more abruptly to lateral
margins, umbo prominent, beak narrow, elevated and incurved over cardinal
area, which latter is depressed triangular, not reaching to cardinal extremities;
foramen of medium size, its base to height as two to three ; in the center of
the valve is sometimes a slight linear elevation, which extends from beak to
front, visible ; lateral margins regularly but gently curved ; anterior margin
forms a regular semi-circle, seldom showing in its center a slight sinuosity.
Dorsal valve either flat or even a little concave, rarely being slightly convex,
often showing a gentle linear depression in the center line of the valve from
beak to front ; hinge-area narrow, almost linear ; beak small and incurved.
Surface marked by fine radiating striae, which increase towards the margins
by bifurcation ; the lateral ones are strongly curved outwards. This beautiful
species is closely allied to Orthis testudinaria, and, perhaps, more nearly to
O. parva, both of which are Lower Silurian fossils. In our specimens the
shell is generally more elongated, and the beak more extended, while the sur-
face is more finely striated. Orthis elegantula is easily distinguished. In

38 PALAEONTOLOGY OF KENTUCKY.

regard to size, it is impossible to give any dimensions, inasmuch as we find
the shells from the size of a small pea to that of an average hazelnut.

Formation and Locality. — This elegant shell is found abundantly and well preserved in the Niagara
rocks east of the city of Louisville, where it, however, occurs of very small size; the specimen represented
on plate XXXII. is about the largest individual ever found. At Waldron, Indiana, it has attained its
largest size. Average specimens from there measure about five-eighths of an inch in width, and some-
what more in length.

Orthis flabellum. SOWERBY.

Plate XXXIV., figure 30.

Orthis flabellum, Hall. Kep. 4th Geol. Dist.— 1843.
Orthis flabellum, Sowerby. Murch. Sil. Syst., p. 639 — 1839.
Orthis flabellum, Var ? Hall. Pal. N. Y., Vol. II., p. 254—1852.

Shell of medium size ; semi-oval or semi-elliptical ; hinge-line equal to
greatest width of shell ; cardinal angles rectangular or slightly acute ; lateral
margins sometimes slightly contracted below extremities ; balance of the
lateral margins and base form a regular curve ; shell plano-convex. Ventral
valve depressed convex, almost flat. The shell before me has, in its central
line, a gentle depression, beginning at about one- third of whole length of
shell from base, and extending to front, forming a kind of mesial sinus, but
I am not able to find out with certainty whether this sinus is really a natural
character of shell, or whether it is the result of distortion. I am inclined to
take it for a real sinus, inasmuch as balance of shell does not show any signs
of having been subjected to any violence. The dorsal valve is moderately
convex in its marginal portion, but almost flat in its central part or in the
nmbonal region.

The cardinal extremities are slightly deflected, incurving the surface between
them and the umbo somewhat. The cardinal area of the ventral valve is of
moderate size, forming a low triangle ; it is divided by a triangular fissure,
partly closed ; the area of the dorsal valve is narrow, almost linear ; the dorsal
beak incurves into ventral foramen.

The surface of the shell is ornamented by about twenty-four to thirty simple,
prominent, sub-angular radii, which increase in number by interpolation.
These radii are crossed by several marked, concentric lines of growth, which
divide the surface in several concentric zones, and give the shell, wherever they
become crowded, which is mostly the case at the margins, a rugose appear-
ance.

Formation and Locality. — The only specimen which I ever have seen, and which belongs to my
own collection, I found in the strippings of one of the quarries east of the city of Louisville; it was
surrounded by Niagara clay, and belongs undoubtedly to the Upper Silurian formation.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 39

Orthis goodwini. N-SP-

Plate XVII., figures 30, 31 and 32.

Shell small, sub-circular or sub-quadrate ; moderately convex in both valves ;
hinge-line short, equal or less than half width of shell ; cardinal extremities
rounded ; lateral margins almost straight, or very slightly curved; they diverge
towards base, in consequence of which greatest width of the shell is close to
base or front; the basal margin is broadly curved, with its central portion
either straight or slightly inflected.

Ventral valve is somewhat more convex in its umbonal region than dorsal,
but in its basal half it is the reverse. Its greatest convexity is just below
umbo, from where it slopes in a very gentle curve to lateral and basal margins,
but more rapidly, even almost abruptly, to the cardinal lines ; umbo moderate,
beak a little elevated above opposite valve, sharp- pointed and slightly arched,
but not incurved. Cardinal area short, but comparatively high, limited by
sharp margins, and divided by an open, triangular foramen, which is partly
closed at its base by the cardinal process of the dorsal valve.

Dorsal valve moderately convex ; point of greatest convexity a little above
middle of valve, from where it slopes in a gentle curve to all the • margins and
to the beak, giving the valve over its whole surface an even convexity, with
the exception of a narrow strip in the middle, which extends from beak to
base, and which is slightly depressed. This mesial depression is deepest in its
middle portion; it is only faintly marked upon the umbo, and it becomes
shallower but wider towards the base. The surface of both valves is orna-
mented by fine, thread-like radiating striae, which increase in number, partly
by bifurcation, but mostly by intercalation ; these radii are crossed by several
concentric lines of growth, which become more numerous towards basal mar-
gin. In regard to size, the specimen illustrated on plate 17, figures 30, 31 and
32, is of about the average size, though a few specimens have been found which
are considerably larger.

Formation and Locality. — Pound mostly in the rotten hornstone in upper strata of the Devonian
formation at the Falls of the Ohio. This species I name in honor of Prof. A. C. Goodwin, formerly of
Charlestown, Indians, an ardent collector.

Orthis hybrida. SOWKBBY.

Plate XXXII., figures 32 to 35.

Orthis hybrida, Sowerby. Murch. Sil. Syst., p. 630—1839.
Orthis hybrida, Hall. Geol. Kep. 4th dist., page 107—1843.
Orthis hybrida, Hall. Pal. N. Y., Vol. III., p. 253—1852.
Orthis hybrida, Hall, llth Rep. of Indiana, p. 284—1881.

Shell small, lenticular or depressed spheroidal, wider than long, valves nearly

40 PALAEONTOLOGY OF KENTUCKY.

equal ; the ventral one depressed from center to base, while the other one is
regularly convex ; beak a little elevated above the other and slightly incurved ;
hinge-line much shorter than width of shell ; cardinal extremities rounded ;
hinge-area small. Dorsal valve slightly convex ; beak and hinge area small.

Surface covered by fine radiating striae, which increase towards the front
by interpolation and bifurcation. The interpolated striae start at anterior part
of umbo, the bifurcation commences at the middle of the valves ; sometimes
the bifurcation is repeated or double ; concentric lines of growth divide the
surface of each valve into different concentric zones, which are more promi-
nent in younger than older individuals. In young shells the shape is more
ovate, in old ones more circular, besides the smaller specimens are more gib-
bous than the large ones.

This species is as variable in size as Orthis elegantula ; it ranges from the
size of a pea to that of a silver half-dime and more.

Formation and Locality. — Niagara group east of the city of Louisville, Ky., where very perfect,
but also rery small specimens are pretty abundantly found. The largest shells of this species are found
at Waldron, Indiana. The individual represented on plate XXXII. is of the average size found near
Louisville.

Orthis livia. BILLINGS.

Plate XVI., figures 23 and 24; Plate XVII., figures 33, 34 and 35.
Orthis livia, Billings. Can. Jour, of Ind. Sci. and Art, No. 27 — 1860,
Orthis livia, Billings. Can. Jour., Vol. 5, p. 267 — 1860.
Orthis livia, Hall. Pal. N. Y., Vol. IV., page 38—1867.
Orthis livia, Billings. Pal. Fossils, Vol. II., pt. I., p. 32—1874.

This species w;is established and first described by Mr. Billings, of the
Canadian Geological Survey. I will, therefore, only copy his description; his
figures correctly agree with mine.

"Shell sub-orbicular or sub-quadrate; length about eight-ninths of the
width ; greatest width usually a little in front of the middle ; length of
hinge-line one-half to two-thirds the width of shell; cardinal extremities
rounded ; sides in most specimens somewhat straight, often sufficiently
curved to give a circular aspect to shell ; front angles obtusely rounded ;
front margin in general broadly convex, sometimes, in a small central por-
tion, nearly straight. Dorsal valve of medium convexity, most elevated about
the middle; the outline forming an uniform arch from depressed beak to
front margin ; slope from umbo to cardinal angles gently concave ; sometimes
a barely perceptible mesial depression, commencing in a point at the beak,
and becoming obsolete at one-half or two-thirds the length ; area small, lying
in plane of the lateral margins; beak minute, forming a small triangular
projection, rising scarcely one-fourth of a line above edge of area. Ventral

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 41

valve moderately convex, most elevated at between one-fourth and one-third
the length from beak, thence descending with a flat or gently convex slope to
the lateral margins, with a somewhat concave one to the front, and also to
hinge-line and cardinal angles. The concavity towards the front is not found
in all specimens ; some shells have basal portion either flat or slightly convex.
The ventral umbo is small and neatly defined ; beak small, pointed, and some-
what incurved, but scarcely overhanging edge of area ; area triangular and
somewhat larger than the dorsal one. Foramen not observed. Surface covered
with small sub-angular radiating ridges or striae, of nearly uniform size, from
eight to ten in the width of three lines, increasing by bifurcation, strongly
curved outwards on lateral parts of shell ; the interspaces sub- angular and
equal in size with the striae.

"In very perfect specimens very fine concentric, sub-lamellar striae are visible,
seven or eight to one line. In certain conditions of preservation, also, the
radiating striae are seen to be sub-tubular, and exhibit numerous small oval
or circular openings on their edges, each about the eighth or tenth of a line in
width, and from one-fourth to two- thirds of a line distant from each other."
(Billings.) The largest specimen which I have seen of this species is the one
illustrated on plate 16, figures 23 and 24, though, according to Mr. Billings'
statement, this species attains in some specimens a considerably larger size.

This species is allied to Orthis vanuxemi, but is more coarsely striated.

Formation and Locality. — Found in the rotton hornstone in the upper strata of the Devonian
formation, in Jefferson county, Kentucky, and in Clark county, Indiana. It is rarely found in specimens
of the size as shown in the illustration, while smaller shells, like those figured plate 17, figures 33, 34 and
35, are not so rare; with these latter there is, however, the trouble to distinguish them from smaller
specimens of vanuxemi.

Orthis linneyi. w. SP.

Plate XXXIV., figures 7 to 13.

Shell of medium size; sub-circular or sub-elliptical; width exceeding
length; hinge-line short, measuring little more than one-third the width of
the shell ; cardinal extremities broadly rounded ; lateral margins regularly
curved ; basal margin broadly curved, showing in the dorsal view a slight
emargination, and in ventral view a small basal extension in the central part
of the front. (Figure 9, on plate XXXIV., shows a basal extension, where it
should show a small sinus or inflection.) In regard to depth, it varies from
moderately convex to gibbous.

Ventral valve is mostly less convex than the opposite one ; its greatest con-
vexity is at the umbo, from where it slopes in a more or less curved line to
baso-lateral margins, and more abruptly to the cardinal borders ; central part
of valve is depressed, forming a mesial sinus, which extends from beak to

GEOL. SUR. — 6

42 PALAEONTOLOGY OF KENTUCKY.

base, and increases rapidly in depth and width towards front ; it has a lingui
form basal extension, which, however, does not deflect from the regular curve
of the sinus, to meet the dorsal indentation. Ventral umbo is more or less
prominent in different specimens, the beak elevated, pointed and arched, but
not incurved ; hinge-area is short but high, forming in some individuals almost
an equilateral triangle ; the larger portion of the hinge-area is occupied by a
comparatively large, open, triangular fissure. The dorsal valve is varying
from moderately convex to gibbous, having its greatest convexity just below
the umbo, from where it slopes in a more or less stronger, regular curve to
the baso-lateral margins, and abruptly to the apex and the cardinal borders ;
it has a mesial fold of moderate elevation, which commences to rise above the
general surface just below the umbo, from where it extends to the base, only
slightly increasing in width and depth. The dorsal umbo is somewhat in-
flated, and the beak small and incurved. The dorsal hinge-area is small,
about one-half the size of the ventral. The surface is covered by simple,
rounded or sub-angular radiating plications, of which usually three, but
sometimes four, occupy the sinus, and generally four, but sometimes five, are
placed on the mesial fold, while from four to seven or eight are seen on each
side of the mesial fold or sinus. In some specimens of this species there
exists a decided inequality in the lateral parts, consisting not so much in size
as in the number of plications. I have, for instance, one shell before me,
where the right side of the dorsal valve has only four ribs, while the left side
contains six. On the ventral valve is the same difference between the number
of the ribs of both sides. This inequality exists in a good many, though not
in all specimens. There is an indication of very fine radiating lines on and
between the plications. Fine concentric lines cross the plications, which
become lamellose and imbricating towards the front.

Formation and Locality. — This species is named in honor of W. M. Linney, the able Assistant
Geologist of our State, who collected this shell in the shales of the Hudson River or Cincinnati group,
near Danville, Kentucky. It is found in excellent, almost perfect specimens, and seems to be somewhat
abundant It also occurs in the base of the Lower Hudson, in Fayette and Franklin counties, Kentucky.

Orthis nisis. HALL.

Plata XXVII., figures 4 and 5,

Orthis nisis, Hall. 24th Rep. on N. Y. State Museum, page 181 — 1872.
Orthis nisis, Hall. 27th Rep. on N. Y. State Museum, pi. 9., figs. 1-8 — 1875.

Shell depressed-pyramidal when resting on the dorsal valve. Dorsal valve
semi-elliptical, flat or slightly concave in middle, and gently convex on each
side. Length and width about as two to three ; area about one-quarter as
wide as that of the ventral valve. Ventral valve depressed-pyramidal; the

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 43

apex projecting backwards over the area. The elevation about equal to half
the length of the dorsal valve ; area twice as wide as high, fissure very nar-
row and slender, and reaching to the apex. Surface marked by strong angular
striae, which are increased by interstitial additions, to the number of twenty-
eight or thirty, on the margin of the shell ; striae crossed by distinct lines of
growth.

Length, five lines on the dorsal valve ; width, seven lines. This species is
of the type of Orthis tricenaria, of the Trenton group, but its beak is much
more elevated, its area higher, and its striae more angular, and these are
increased by interstitial additions, while in O. tricenaria and its' congener O.
pectinella the striae are simple.

Formation and Locality. — Found in the upper strata of the Niagara formation in the quarries east
of the city of Louisville, Ky., where well preserved specimens are, however, rather rare.

Orthis propinqua. HALL.

Plate XVI., figures 1, to 3, and 7 to 11.

Orthis propinqua, Hall. Tenth Rep. on St. Cab., p. 110—1857
Orthis propinqua, Hall. Pal. N. Y., Vol. IV., p. 43—1857

Shell of more than medium size ; transversely elliptical or sub-quadrate ;
varying from moderately convex to gibbous ; hinge-line about one-half the
width of shell ; cardinal extremities broadly rounded ; lateral margins regu-
larly curved beyond the front angles ; basal margin broadly curved and trun-
cated or even somewhat inflected in its central part.

Ventral valve less gibbous than the dorsal ; very prominent at the umbo,
sloping very abruptly towards the cardinal angles, but more gently towards
lateral and baso-lateral margins ; flattened in center ; the lower half marked
by a gradually increasing, broad and undefined sinus, which gives a strongly
upward curved outline to basal or front margin ; beak acutely pointed and
slightly incurved ; cardinal area elevated and concave, and divided by a tri-
angular foramen, which is open, and twice as high as wide in its base. The
dorsal valve is larger and more gibbous than the opposite one ; its greatest
convexity fs a little above the middle of the length, curving abruptly to the
cardinal and cardino-lateral margins, and somewhat more gently to the front
and baso-lateral margins. The cardinal extremities are sometimes slightly
deflected, and the surface at the cardinal angles a little concave. Cardinal
area is inclined to that of the ventral valve, and about one-half or two-thirds
as wide. Surface marked by fine, unequal, radiating striae, which increase in
number by intercalation, and are crossed by fine concentric striae, and, at un-
equal intervals, by stronger imbricating, lamellose lines of growth.

This species resembles closely O. multistriata of the Lower Helderberg

44 PALAEONTOLOGY OF KENTUCKY.

group, from which it differs only in internal characters. It is also closely
allied to O. tulliensis, from which it can only be distinguished by characters of
the interior.

Formation and Locality. — Occurs in the upper strata of the Devonian formation, in Jefferson
county, Kentucky, and in Clark county, Indiana. Fair specimens are rather rare.

Orthis rugaeplicata. HALL.

Plate XXVII., figures 1, 2 and 3.

Orthis rugaeplicatas, Hall. 24th Rep. N. Y. St. Mus., p. 182—1872.
Orthis rugaeplicatas, Hall. 27th Rep. N. Y. St. Mus., pi. 9, figs. 1, 2 and 3—1875

Shell small, subquadrate, four-fifths as long as wide, gibbous ; cardinal line
nearly equal to the greatest width of the shell ; cardinal angles obtuse, basal
margin nearly straight. Dorsal valve convex, with a distinct median sinus
extending from beak to base ; cardinal area linear ; length three lines, width
four lines. Ventral valve depressed-pyramidal, marked along the center by a
distinct angular plication or fold ; beak projecting slightly backwards over
the area ; area moderate, less than one- third as high as wide, and divided in
the center by a moderately wide fissure.

Surface marked by very strong, sharply angular plications, which are in-
creased by interstitial additions, and of which there are about fifteen on the
margin of each valve, with a few other incipient ones.

Formation and Locality. — Found in the Niagara formation in the quarries east of the city of
Louisville, Ky. It is, when well preserved, an elegant little shell: but perfect, even fair specimens, are
very rare ; those of Dr. James Knapp, deceased, and my own, are all, so far found

Orthis subnodosa. HALL.

Orthis subnodosa, Hall. Trans. Alb. Inst., Yol. X.— 1879.
Orthis subnodosa, Hall, llth Geol. Rep. of Ind., p. 286—1881.

It appears from Prof. Hall's description and illustration in the above men-
tioned report of Indiana, that he was then in possession of only the ventral
valve of this species, and the same is the case with me to-day.- Prof. Hall
describes this shell as follows :

Ventral valve sub-orbicular, length and width about as ten to fourteen ;
hinge-line much shorter than the greatest width of the shell ; an undefined
mesial depression in the lower half of the shell. (In this last feature my
shell differs from Prof. Hall's, in having this depression extend all the way
up to the apex, but it is possible that this extended sinus was caused by
the breaking off of one of the adjacent ribs.) The umbo is comparatively
prominent ; beak small and slightly arched ; area small, triangular, apparently

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 45

hot occupying more than half the width of the valve ; foramen large, triangu-
lar, reaching to the beak, wider than high. Surface marked by sub-angular
plications, of which three occupy the mesial sinus, the central one being inter-
stitial, coming in below the umbo ; there are about ten plications on each side
of the mesial depression ; some of them originate by bifurcation or intercala-
tion. The radii are crossed by fine concentric lamellose lines of growth,
which gives them a sub-nodose appearance. This species has some resem-
blance to Orthis fissicosta, of the Hudson River group, but its cardinal ex-
tremities are more rounded and its cardinal area is not as high.

Formation and Locality. — Prof. Hall's specimen was found at Waldrori, Indiana, and that before
me I collected in the quarries east of the city of Louisville. It was imbedded in the white Niagara clay.

Orthis vanuxemi. HALL.

Plate XVI., figures 4, 5, 6, 12, 12o, 13 and 14.
Orthis vanuxemi. Hall. Tenth Hep. on St. Cab., p. 136 — 1857.
Orthis vanuxemi. Hall. Pal. N. Y., Vol. IV., p. 47—1867.

Shell above medium size, sub-circular, or transversely sub-elliptical ; upper
part of the shell bi-convex ; lower or front part generally concavo-convex ;
shell strongly compressed ; hinge-line very short, little more than one-third
the width of the shell ; cardinal angles broadly rounded ; lateral margins
strongly curved, and the front in its central half inflected or emarginate.
Ventral valve mostly concave or sometimes flat, with the exception of the
umbonal region, which is slightly convex ; beak small, seldom extending
beyond that of the dorsal valve, but often even somewhat less elevated ; it
is pointed and gently arched, but not incurved ; cardinal area small, forming
a low triangle, which is divided in its center by a small triangular foramen,
partly filled by the cardinal process of the opposite valve. Dorsal valve
moderately, but even and regularly convex over the whole surface of the
valve, with the exception of the umbonal region, which is slightly more con-
vex ; the beak is scarcely distinct from the cardinal border and not incurved ;
cardinal process prominent and partly closing the ventral foramen ; cardinal
area small, about two-thirds as wide as the ventral, flat and inclined towards
that of the opposite valve.

Surface of both valves ornamented by fine, closely arranged, radiating
tubular striae, which are perforate at intervals, increasing in number partly
by bifurcation and partly by intercalation, and crossed by very fine indistinct
concentric lines, and at greater intervals, by more distinct concentric, imbri-
cating lines of growth ; entire surface granulate or punctate under a magnifier.
Striae from twelve to sixteen in the space of two lines near the beak, and
from seven to nine in same space near margin.

46 PALEONTOLOGY OF KENTUCKY.

This species resembles closely Orthis michelini, of Laveille, but shows several
points of difference. The later species is here, in our Carboniferous rocks,
greatly more compressed.

Formation and Locality. — The specimens figured show the general size. Occurs in the upper
strata of the Devonian formation in Jefferson county, Ky., and in Clark county, Indiana.

Genus Tropidoleptus. Han.

Tropidoleptus, Hall. Pal. N. Y., Vol. IV., p. 404—1867.
Etymology: tropis, a carina; and leptos, slender.

Shell transversely sub-oval or semi-elliptical, concavo-convex; hinge-line
extended, not crenulate ; articulating by teeth and sockets. Ventral valve
convex, with a distinct area and wide fissure beneath the beak. Dental
lamellae distinct from the margin of the fissure ; crenulate.

Dorsal valve concave, with crenulate dental fossets ; a strong cardinal pro-
cess with diverging lobes in interior, which support slender crura that converge
to and unite with the median crest. Surface plicate ; shell structure punctate.

Type of the genus is T. carinatus.

Tropidoleptus carinatus. CONRAD.

Plate XVII., figures 14 and 15.

Strophomena carinata, Conrad. Ann. Geol. Rep., p. 64 — 1839.
Leptaena laticosta, Hall, in 1883.
Leptaena laticosta, of Owen and others.

Tropidoleptus carinatus, Hall. Tenth Rep. on St. Cab., p. 151 — 1857.
Tropidoleptus: Genus described and illust. in 12th Rept. on St. Cabinet. — 1869.
Tropidoleptus carinatus, Hall. Pal. N. Y., Vol. IV., p. 407—1867.

Shell of medium size, concavo-convex, semi-elliptical, length sometimes
nearly equalling width ; hinge-line variable in size, but generally a little less
than greatest width of shell ; cardinal extremities rarely rounded, generally
forming with the lateral margins an obtuse or right-angle. The lateral mar-
gins are of double curvature, starting from the cardinal extremities, they curve
at first inward for about one- fourth of the length, thence they curve outwards,
combining with broad curve of base to an almost regular semi-circle.

Ventral valve ventricose, sub-carinate in the center by a stronger and more
elevated plication, forming a kind of mesial fold, from which the valve slopes
in a gentle curve to lateral and basal margins ; umbo small, and the beak
somewhat encroached upon by the broad foramen ; cardinal area narrow, ex-
tending to the extremities, its margins almost parallel with t}ie hinge-line ;
the cardinal angles deflected. The area is longitudinally striate, which feature
is, however, obliterated in silicified specimens.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 47

Dorsal valve moderately concave, sometimes nearly flat, often with a slight
mesial depression or sinus, which is usually only noticeable in the basal half ;
apex small and projecting a little beyond the hinge-line, partly closing the
triangular fissure of the other valve. There is a narrow, almost linear area,
interrupted in the middle by a wide pseudo-deltidium which covers the ex-
tremity of the cardinal process. Surface marked by about eighteen to twenty
broad, simple, rounded plications, which are wider than the spaces between
them. The central one on the ventral valve is stronger and more elevated than
the balance, while on the dorsal valve there is a corresponding wider and
deeper groove. Bifurcation is only noticed in rare instances. Fine undulating,
concentric striae ornament the surface, and some stronger imbricating lamellae
mark the different stages of growth. It appears that our Kentucky specimens
differ slightly from the New York ones, which latter have rounded extremities
and almost straight lateral margins, while in the Kentucky specimens extremi-
ties and lateral margins are as before mentioned.

Formation and Locality. — In the upper strata of the Devonian limestone in Clark county, In-
diana, and some few places south-east of the city of Louisville, Ky. The Indiana specimens are very
tine and perfect, often showing the two valves separated, except -at the hinge. Our shells are almost all
silicified and have different sizes ; the one represented on plate XVII. belongs to the larger ones.

Genus Anastrophia. Han.

Anastrophia, Hall. Pal. N. Y., Yol IV., p. 373—1867.

Etymology: ana, witfi; strophe, a turning round, alluding to the valves having reverse relation; the
dorsal valve is larger than the other, and its beak overlaps the ventral beak.

Shell rotund or gibbous, with the valves, as in ordinary Pentamerus, reversed.
The ventral valve is the smaller, gibbous in its upper part, depressed or sinuate
below, with the Y-shaped pit sessile for nearly its entire length ; a small flat-
tened space on each side of the fissure. The dorsal valve is ventricose, larger
than the ventral, with prominent umbo. The hinge-plate is extended in gradu-
ally converging vertical lamellae, which are joined to the shell throughout their
length, while the crura are extended into the cavity in thin free lamellae. The
species : Pent, verneuilli, P. internascens and P. reversus are the types of this

new genus.

Anastrophia internascens. HALL.

Plate XXXII., figures 17 to 20.

Anastrophia internascens, Hall, llth Geol. Kep. of Indiana — 1881.
See list of synonyms in said llth Rep. of Indiana.

Shell transversely sub-elliptical, ovoid or sub-globose in different stages of
growth ; the length and width are sometimes nearly equal. Valves of young
specimens nearly equal in convexity, in older individuals the dorsal valve

48 PALAEONTOLOGY OF KENTUCKY.

becomes the more gibbous. Ventral valve moderately convex in young or
medium sized specimens, and gibbous in the upper part of old ones ; the
anterior portion depressed, and marked by a broad, undefined sinus ; beak
short, acute, closely incurved over the umbo of the opposite valve, area small,
short and sharply denned. Dorsal valve gibbous, and in old individuals the
umbo projects beyond the beak of the ventral valve, with the apex incurved
beneath the beak of the latter ; central portion of the valve toward the front
more elevated, and sometimes presenting a broad, undefined mesial fold. Sur-
face plications abruptly elevated, rounded, angular or sub-angular, becoming
depressed and sometimes obsolete on the cardinal slopes, usually simple, en-
larging toward the front of the shell, rarely bifurcating or intercalating in a
remarkable manner on the sides, where the folds bend abruptly outwards to
the cardino-lateral margins ; plications crossed by arching imbricating striae
or lines of growth, which are sometimes very conspicuous. The dimensions
of this species are very variable in different individuals. The figures on plate
XXXII. show the average size of Louisville specimens.

Formation and. Locality. — Occurs in the Niagara strata in the quarries east of the city of Louis-
ville, Ky., in fine, well preserved specimens, which are, however, rather rare, and which never attain the
size of individuals from "Waldron. To avoid mistakes, I will here draw the attention of the students of
palaeontology to the fact that in this species the valves are easily confounded, inasmuch as the dorsal one
is larger than the other, and its beak generally more prominent than the one of the ventral valve.

Genus Camarella. Bnimgi.

Camerella, Billings. Can. Nat. and Geol., Vol. 4 — 185.9.
Etymology: Kamara, arching chamber; ella, diminutive.

This genus was established by Mr. Billings in 1859, but I have never been
able to see the description of his genus, which he should have repeated in his
"Palaeozoic Fossils" of the Geology of Canada, Volume I., 1861 to 1865, where
he describes eight different species of this genus.

i The different shells which he places in his new genus have the following
characteristics : Shells sub-circular or ovate, unequivalve but equilateral ;
both valves more or less convex, having their greatest width below the middle
of the length, usually close to the base or front. The surface is generally
plicated but also smooth, and only marked by concentric lines of growth. The
internal characters of this genus are not known.

Camerella congesta. CONRAD.

Atrypa congesta, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. 8 — 1842.
Atrypa congesta, Hall. Geol. Rep. 4th Dist. N. Y., p. 71—1343.
Atrypa congesta, Hall. Pal. N. Y., Vol. II., p. 67—1852.

Shell sub-orbicular, gibbous, often more or less ovate, Ventral valve much

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 49

larger and more elevated at the beak than the dorsal valve, with a deep mesial
furrow, which commences at the beak and gradually deepens and widens
towards the base or front of the valve, where it forms a linguiform basal ex-
tension, which is strongly elevated to fit into a corresponding indentation of
the dorsal valve. The mesial depression of the ventral valve is margined by
a more or less obtusely carinated fold, produced by a depression of the shell on
each side of the sinus. Dorsal valve with a strong, elevated mesial fold, and
a depression on each side, beyond which is sometimes an obscure fold. Beak
of the ventral valve elevated and strongly incurved over beak of opposite
valve, while the dorsal beak is small and incurved. The entire surface is
covered, in well preserved specimens, with fine concentric striae, and with a
few imbricating lines of growth near the front. The specimen before me does
not show any of these lines on account of its silicified condition. This species
is subject to considerable variations in its form, but is, in spite of that, easily
identified by its rotund and gibbous form.

Formation and Locality. — This species usually occurs in the lower strata of the Clinton group;
but I found my specimen in the Niagara rocks near our city, from which it appears that the lower strata
of our Upper Silurian rocks must belong to that group, as is also indicated by several other fossils of de-
cidedly Clinton character.

Genus Pentamerella. Han.

Pentamerella, Hall. Pal. N. Y., Vol. IV., p. 373—1867.
Etymology : Diminutive of pentamerus.

Shells ovate, more or less rotund, with a sinus on the ventral valve, and a
mesial fold on the dorsal valve ; internal structure of the ventral valve as in
Pentamerus knighti. Dorsal valve with the crura or lamellae of the hinge-
plate conjoined, so as to form a separate, trough-shaped cavity, which unites
with the inner surface of the valve ; a narrow area on each side of the fissure,
and a flattened space or a false area along the cardinal margin of the valve.
Pentamerella arata is the type of this genus.

Pentamerella arata. CONRAD.

Plate XIII., figures 17 to 20.

Atrypa arata, Conrad. Ann. Rep. on Pal. of N. Y., p. 55 — 1851.
Atrypa octocostata, Id. Ib.

Pentamerus aratus, Hall. Tenth Eep. St. Cab., p. 120—1857.
Pentamerella arata, Hall. Pal. N. Y., Vol. IV., p. 375—1867.

Shell of medium size, ovate, more or less convex or gibbous, becoming
arcuate-ovoid in old shells ; proportion of length to width variable ; in most
cases both are equal, but in some individuals the width exceeds the length,

QEOL. SUR. — 7

50 PALAEONTOLOGY OF KENTUCKY.

and in others the length is the larger. Hinge-line is also very variable ; in
some specimens it is scarcely noticeable, in others of considerable size. Ven-
tral valve regularly convex in young individuals, but becoming gibbous in old
ones. The mesial sinus is regularly developed, but undefined and very shal-
low, even at the front ; it starts below the umbo and forms a slight convexity
in the basal margin, which is in most shells regularly curved ; beak elevated
and strongly incurved over the fissure, which it partly, sometimes wholly,
closed ; the foramen almost as wide in the base as its height ; cardinal area
sometimes scarcely visible, while again in some shells it forms a regular tri-
angle; bounded by a faint but distinct elevation on each margin. Dorsal valve
in young shells more or less convex, and sometimes gibbous in the upper part,
and often only moderately convex in older shells ; mesial fold starts below
the umbo, never well-defined, and not much elevated, still distinctly developed.
Surface ornamented by rounded or sometimes- by somewhat angular plications,
which, in rare instances, reach all the way back to the apex, but which are
generally limited to the lower half or two-thirds of the valve ; they increase
by bifurcation. The interior of the ventral valve has an elongate spoon- shaped
pit ; the inner extremity of which is free for a considerable extent, and the
upper part supported on a central septum, which usually extends less than
half the length of the shell from the apex. In the dorsal valve, the crura or
lamellae are conjoined at their bases, making a Y-shaped trough or pit, which
is attached to the valve in its upper part and continues sessile for about one-
half the length of the shell. This species shows much variety in aspect and
form, caused by age and the conditions under which it lived, which were either
favorable or unfavorable to its development. Conrad's species, Atrypa octo-
costata, includes forms which are easily connected by intermediates with Pent,
arata, and which, therefore, belong to this species. In size it differs greatly.
The figures on plate XIII. represent an individual of more than average
size.

Formation and Locality. — Occurs, not rarely, in the Corniferous limestone of Kentucky and Indi-
ana, at and around the Falls of the Ohio, where fair and sometimes even very fine specimens are procured.

Fentamerella papilionensis. HALL.

Pentamerus papilionensis, Hall. Geol. Hep. of Iowa, Vol. I., part II., cited on page 514 — 1860.
Pentamerus papilionensis, Hall. Thirteenth Rep. on the State Cabinet, p. 86 — 1860.
Pentamerella papilionensis, Hall. Pal. N. Y., Vol. IV., p. 377 — 1867.

Shell of medium size, ventricose, broadly ovate, often wider than long, more
or less gibbous and arcuate in old shells.

Ventral valve gibbous or ventricose above, becoming depressed in the middle
into a broad, shallow, undefined sinus, which scarcely reaches to the beak, and

FOSSILS Otf THE SILURIAN AND DEVONIAN BOOKS. 5i

in some cases not much above the middle, and is little produced in front. 1
have a specimen before me, where the plication of the mesial sinus is even
overreaching the general surface of the valve ; sides curving abruptly to the
margins ; beak incurved, obtuse, arching over the broad fissure ; cardinal area
sloping on both sides down to about the middle of the valve, bounded by a
sharp, somewhat curved line of demarcation, having a considerable size and
being somewhat concave.

Dorsal valve moderately convex and regularly curving to the lateral and
basal margins ; mesial fold not much elevated, and limited to the lower half
of the valve, where it is well defined. Surface plicated, the ribs rounded or
sub-angular, becoming obsolete towards the beak, and prominent in the basal
half. There are generally two, sometimes three plications in the sinus, and
three, rarely four on the fold, while the lateral slopes of the valves contain
from four to five. The plications are crossed by fine concentric lines of growth,
which sometimes at irregular intervals are crowded into squamose, imbricating
lines. The entire surface is finely papillose or punctate, and, when well pre-
served, might be mistaken for a punctate shell. The substance of the shell
is lamellose -prismatic and brittle. The interior of the ventral valve shows a
broad, short and deep spoon-shaped pit, extremity of which is bent abruptly to
dorsal side. The septum, supporting the conjoined lamellae, extends from
one-third to one-half the length of the valve, and in some examples may
extend still further" towards the anterior margin. This species bears much
resemblance to P. arata, but its plications are less numerous on the whole
valve ; less numerous and stronger in the mesial depression and elevation,
and its shell is less arcuate.

Formation and. Locality. — Found in the Corniferous limestone in the neighborhood of the Falls of
the Ohio in Kentucky and Indiana. Pretty abundant, but fair specimens rather rare.

Fentamerella thusnelda. N.SP.

Plate XXXI., figures 26, 27 and 28.

Shell of medium size, ovoid or sub-quadrate; cardinal extremities rounded,
forming in the beak of the dorsal valve an angle of a little more than sixty
degrees ; length exceeding the width considerably, giving to the shell an elon-
gate, somewhat slender appearance. Ventral valve ventricose, even gibbous ;
convexity regular from beak to front, and also transversely ; greatest convexity
a little above the middle of the valve ; mesial sinus indicated by two very
strong plications, and by a wide and deep groove on each side of them ; the
summit of these plications drops not at all, or at least very slightly, at the very
front of the valve, below the regular surface ; the two prominent grooves ex-
tend almost to the beak, forming on the umbo only one rib, which separates

&2 PALEONTOLOGY OF KENTUCKY.

into two plications in front of the beak ; these mesial ribs are considerably
prolonged in front, producing a sub-quadrilateral extension ; beak is prominent
and incurved ; cardinal area large, extending to the extremities, and bounded
by a well-marked, regularly curved line of demarcation ; fissure of moderate
size, but partly closed by the beaks of both valves.

Dorsal valve depressed convex, curved slightly in the upper half of the
valve ; lateral portions of lower half almost flat ; mesial fold formed by three
strong plications, which are united into one single elevation on the umbo,
where it is only faintly visible ; below the umbo the three mesial ribs separate
and extend to a little beyond the front, where they are considerably elevated ;
beak moderate and incurved into the foramen of the other valve ; cardinal
area only linear. Surface marked by about twelve sub-angular plications, of
which those in the mesial depression and elevation are considerably stronger
than those on the lateral slopes ; the lateral ribs on the dorsal valve are single
and of equal size; those on the ventral valve increase by bifurcation, and those
nearest to the mesial furrows appear to be stronger than the more lateral
ones.

This species resembles Pent, arata and Pent, papilionensis, also Pent, dubia ;
from Pent, arata it differs by its elongate form, its less numerous plications,
and by its mesial ribs, which are here limited to three in the fold and two in
the sinus, and which are of about double size of the lateral ones ; while in
Pent, arata the mesial plications are larger in number and of almost equal size
with the balance. From Pent, papilionensis it differs in its elongate form, and
in the peculiar character of the mesial plications, which in P. papilionensis
have the same number, but do not differ from the lateral ones by size; and
from Pent, dubia it differs also in form ; while P. dubia has its greatest width
about the middle of the shell, this one has its maximum breadth nearer to the
front, at more than two-thirds from the apex; P. dubia has more plications
generally, and also more on the fold and in the sinus.

Formation and Locality. — Found in the Corniferous limestone surrounding the Falls of the Ohio
in Kentucky and Indiana. It is of rare occurrence here in the neighborhood of the falls ; only two indi-
viduals of this species are known ; they belong to my own cabinet.

Genus Pentamerus.

Pentamerua, Sowerby. Min. Couch., Vol. I. — 1814.
Etymology: penta, five; meros, apartments.

This genus was proposed by Sowerby in 1813 to include all the shells allied
to Pent, knighti, which he made the type of the genus Pentamerus. Dalman
objecting to the name, on the ground that the shell was not five-chambered,
proposed in its stead the name Gypidia, but this latter was never accepted.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 53

This genus included for a while a large number of related species, but there
existed differences which compelled the division into several genera, which
Prof. Hall and Mr. Billings established. Prof. Hall gives the characteristics
of Pentamerus as follows : Shells having rotund or gibbous forms, with the
ventral valve prominent in the middle, and the dorsal valve flattened or de-
pressed towards the front ; lamellae of the dorsal valve distinct, as P. knighti,
P. galeatus and P. pseudogaleatus. Or the form is elongate, with the valves
sub-equally convex, lobed or sub-sinuate ; internal structure like that of P.
knighti, as P. oblongus and P. lens, etc.

Pentamerus complanatus. K. sr.

Plate XXVII., figures 14, 15 and 16.

Pentamerus nysius, var. tenicosta, Hall. 27th Rep. of N. Y. State Museum, plate 10, figures 1, 2 and 3.

Prof. Hall described, in the 24th Report on the N. Y. State Museum, pages
184 and 185, a new species, the Pentamerus nysius, and distinguished of the
same the two varieties : Pent, nysius, var. crassicosta and Pent, nysius, var.
tenuicosta. In the 27th Report on plate 10, he figured two different shells, one
sub-figures 1, 2 and 3, and the other sub-figures 4, 5, 6 and 7, and placed both
in his new species. The great diversity in their form Prof. Hall regards as
the results of age, but not of specific importance. Only on account of the
different size of their radii, he placed them into different varieties. Now I
have before me more than fifty specimens, and find among them both forms,
each one represented by specimens, from very young or small to very old or
large, showing that the age did not cause the diversity of form, as shown in
Prof. Hall's two shells. This difference in shape I consider of sufficient impor-
tance to base upon it a new species, and the only question is now, which of the
two forms shall retain the original name, and which shall form the new species.
The elongated and very gibbous shells represented by figures 4, 5, 6 and 7, show
a marked difference in the size of their costae, which necessitates the separa-
tion of the species into two varieties, to be designated as crassicostus and
tenuicostus ; I, therefore, retain the original name for this form, while the
shell, represented by the figures 1, 2 and 3, forms the new species with the fol-
lowing description : Shell of medium size, broadly triangular, with little
gibbosity ; both valves almost equal in size, form and convexity. The regular
curve of the front margin is only slightly disturbed by a faint mesial exten-
sion; the lateral margins are nearly straight from the apex down to two-
thirds of the length, and slightly curved towards the front. None of the
shells show the least indication of a mesial depression or elevation ; surface
marked by fine radii ; ventral valve a little more convex than the other, being
depressed convex ; greatest convexity below the umbo, from where it slopes

54 PALAEONTOLOGY OF KENTUCKY.

in a slightly curved, almost straight line to the front ; towards the lateral
margins it slopes in a gentle, regular curve, but approaching the margins, it
turns rapidly towards the dorsal valve, where it forms a smooth border ; the
beak is small, straight, and very little elevated above that of the dorsal valve,
often touching the same at equal height. The dorsal valve is depressed convex,
maximum convexity below the umbo, from where it slopes in a very gentle
but regular curve to front and sides ; only a very small strip of this valve at
the lateral margins is rapidly and abruptly bent, to meet the smooth marginal
border of the ventral valve ; the umbonal part is strongly curved towards the
other half of the shell ; the beak strongly incurved beneath or against the other
beak.

Surface is marked by fine radiating striae, single and rounded, and number-
ing from thirty to forty. The surface is generally divided by three promi-
nent lines of growth into four zones, which are easily noticed on any fair speci-
men. The umbonal zone is always smooth, either the striae did not develop
before a certain age, or if this portion was ever covered with radii, they became
obliterated in the course of time.

Formation and Locality. — This beautiful species, of which my own cabinet possesses a few very fine
and perfect specimens, is found in the Niagara rocks in the quarries east of Louisville, Ky. It is very
rare.

Pentamerus globulosus. K.SP.

Shell very small ; sub-globose ; width exceeding the length ; very ventricose
or gibbous ; ventral valve very convex ; greatest convexity about the middle
of the valve, from where it slopes, in a regular but strong curve, to the beak
and to the lateral and basal margins ; to the cardinal lines it slopes more
abruptly, joining with the curved margins of the hinge-area ; the cardinal area
is small and not defined in its margins, which, as before stated, are curved and
coalesce with the surface of the valve ; umbo is very prominent ; the beak is
elevated and strongly incurved, but does not touch the beak of the opposite
valve, from which it remains sufficiently distant to show a moderately sized,
open, triangular foramen in the ventral hinge-area.

Dorsal valve is sometimes as convex as the ventral, though usually it is less
so. It is most convex in the umbonal region, but flattens in the lateral parts.
Below the middle of the valve its central part becomes depressed into a shal-
low sinus, which does not reach beyond the basal third of the valve ; it is most
perceptible in the basal margin, outside of which it is scarcely to be noticed.
Corresponding with this mesial sinus the ventral valve shows a mesial elevation,
which is also confined to the basal third of the valve, and outside of the front
margin hardly observable. In some specimens these mesial depressions and

FOSSILS OF THE SILURIAN AND DEVONIAN BOCKS. 55

elevation are not at all indicated. The surface of the larger portion of both
valves is entirely smooth ; the basal margin shows, however, from eight to ten
plications of different strength and extent on each valve ; the central ones are
stronger and longer than the balance ; they diminish in size and length accord-
ing to their distance from the central point of the base. None of these plica-
tions extend beyond the basal third ; most of them are confined to the border.
An average-sized specimen measures five and one-half lines in width, four and
one-half lines in length, and three and one-half lines in depth. This shell
has some resemblance to P. sub-globosus of Meek and Worthen, from the
Hamilton group, described in the Illinois Report, Volume III., but it differs
from that species by its smaller size, less gibbosity and smaller number of
plications.

Formation and Locality. — Found in the Niagara rocks, east of Louisville, in almost perfect speci-
mens, but rather rare. *

Pentainerus knappi. HALL.

Plate XXVIII., figures 1, 2, 3 and 4.

Pent, knappi, Hall. 24th Rep. N. Y. St. Museum, p. 184—1872.
Pent, knappi, Hall. 27th Rep. N. Y. St. Museum, pi. 10, figures 10, 11 and 12—1875.

Shell broadly elliptical, moderately gibbous above, compressed in front ;
length about one-third greater than width, somewhat obscurely trilobate ; car-
dinal line equal to nearly one-half the width of the shell. Dorsal valve
scarcely smaller than the ventral; moderately gibbous in the upper part,
broadly depressed-convex below the middle, and spreading at the latero-basal
margins. Ventral valve a little more gibbous in the part above the middle
than the opposite valve, and less depressed in the lower part ; the beak nar-
rower below than the other beak, above which it is visibly elevated, pointed
and only slightly arched. Prof. Hall in his description states the beak of the
ventral valve to be closely incurved upon the other valve ; his figures on plate
10; in his report, show it the same way ; this is a mistake, caused by the im-
perfect condition of the specimen from which description and figures were
made. At the time when I had my plates lithographed I had no good speci-
men of this species in my possession, and having then also no access to Dr.
Knapp's shell, which was absent from Louisville, I was compelled to copy Prof.
Hall's figures, carrying his mistake over on my plate. Since then I have ac-
quired several almost perfect specimens of P. knappi, which prove without
doubt the character of the beak as stated by me.

Surface is covered with strong plications, which become almost obliterated
on the umbo, and which diverge and curve outward towards the front ; they
gire rounded, and bifurcate repeatedly with the growth, of the shell, so that

56 PALAEONTOLOGY OF KENTUCKY.

there are several times as many at the margins as at their starting. On most
specimens the central plications form in their basal half, by double bifurcation,
fascicles or bundles of ribs, such as mark so prominently the surface of Spir.
camerata of the Carboniferous. These fascicles are only found on the middle
lobe of the shell; the lateral lobes contain only single and much finer plica-
tions. The sides of the shell, along the cardinal line, and down to the point
of maximum width of the shell, have a smooth surface.

Concentric lines of growth cover the shell. This species resembles some-
what Mr. Billings' Stricklandinia gaspensis, from which it differs by not
having any mesial depression or elevation, and no straight hinge-extension
and narrow area ; while Mr. Billings' shell is covered, even on the sides, by
plications, where P. knappi has a large, smooth lateral area.

Prof. Hall says that this shell resembles, in every feature except the strongly
radiated surface, Pentamerus oblongus, and he does not doubt the possibility
that intermediate forms may be found to connect the two species. It can not
be disputed that this shell greatly resembles some of the broader forms of Pent,
oblongus, from which it certainly branched off by evolution, and I feel certain
that it will maintain its specific character.

Formation and Locality. — Found in the Niagara rocks in, the quarries east of the city of Louisville,
Ky., where it is not very rare, at least not in fractional shells; while perfect individuals are exceedingly
seldom. Prof. Hall named this species in honor of the late Dr. James Knapp, of Louisville, Ky., who first
discovered it, as he did so many other new species, belonging to the palseozoic fauna of Louisville's vicinity.
Dr. Knapp was, for many years, almost the only collector of fossils of our city, thus having the rare
opportunity of getting all the line specimens which our many quarries around the city and the Falls ot
the Ohio afforded.

Pentamerus knotti. x. SP.

Plate XXXII., figures 9, 10, 11 and 12.

Shell below medium size ; broadly ovate, sub-globose ; length and width
about equal ; hinge-line shorter than the greatest width of the shell ; cardinal
extremities rounded ; lateral and basal margins forming usually a regular
curve, but sometimes the front is slightly straighter than the sides. Shell
very gibbous and surface plicated. Ventral valve more gibbous than the
other, having its greatest convexity about the middle of the valve, from where
it curves regularly to the lateral and basal margins, but very abruptly to the
cardinal area, with which it joins without any line of demarcation ; about the
middle of the valve, or, at least, below the umbo, the central portion for the
extent of four plications becomes elevated above the adjacent surface, slightly
increasing in height towards the front, thus forming a mesial elevation or fold ;
the umbo is prominent, and the beak elevated and strongly incurved, but not
overlapping the umbo of the dorsal valve ; the cardinal area is not defined in

FOSSILS OF THE SILUEIAN AND DEVONIAN ROCKS. 57

its margins, as it curves into the general surface of the valve ; the triangular
fissure is either open from cardinal line to apex, or partly closed by beaks of
both valves. Dorsal valve less convex than ventral ; greatest convexity at the
umbo, sloping from there in a gentle curve to the sides and front, but more
rapidly to the cardinal line ; about the middle of the valve a depression sets
in, extending in width over three plications; it increases in depth but very
slightly up to the front, where it forms a small basal extension, which
deflects downwards to meet the small indentation of the other valve. In some
specimens no basal extension exists, or is so small as not to be noticed ; umbo
prominent, and beak strongly incurved below that of the other valve into the
fissure of the latter. Surface marked by from ten to twelve rounded or sub-
angular plications, which are plainly visible at the lateral and basal margins,
but become obsolete before reaching the umbo on both valves. The specimen
illustrated represents about the largest size which this species ever attains.

Formation and Locality. — Occurs in the upper strata of the Niagara rocks in the quarries east of
the city of Louisville, Ky., where it is not very rare. I name this species in honor of W. T. Knott, of
Lebanon, Ky., the efficient Assistant Geologist of our State, who made us acquainted with the geology of
his district,

Pentamerus knighti. SOWSKBY.

Plate XXIX., figures 1, 2 and 17.
Pentamerus knighti, Sowerby. Min. Couch., Vol. I — 1812.

Shell of medium size, sub-ovate and very gibbous ; narrow, with its greatest
width at the base, which is regularly carved. Depth about four-fifths of its
length. Surface plicated.

Ventral valve about twice as deep as the other, very gibbous, and regularly
arched from beak to front. From the longitudinal center line on the summit
of the valve it curves for a certain distance, about half way, gently and regu-
larly towards the lateral margins, then it slopes very abruptly towards the
cardino-lateral angle, where it forms on each side of the beak a large concave,
smooth field. The umbo is narrow but very prominent ; the beak strongly
arched over the umbo of the other valve, but not touching it. Dorsal valve
less gibbous than the other valve, regularly curved from beak to front, and also
towards the lateral margins, except in a small strip at those margins, where the
valve deflects abruptly downwards, joining the smooth concave field of the other
valve by a similar but considerably smaller field. This valve is wider than the
other, except at the front, where both are of equal width. The whole surface,
with the exception of the above mentioned concave fields in the cardino-lateral
angles, is covered by strong, simple sub-angular plications, reaching from beak
to front, and increasing as the shell grows in strength or size and in distance,

GEOL. SUR. — 8 • ,

58' PALAEONTOLOGY OF KENTUCKY.

There are from twenty to twenty- four ribs on each valve. Some concentric
lines of growth are visible, but whether the shell possessed other surface-
markings can not be found out in the silicified condition of the shells, inas-
much as the silicification generally obliterates the finer striae. I have placed
these shells, of which I possess only the two individuals figured on plate
XXIX., as Pent, knighti, though 1 have never seen of that species any correct
and detailed description, nor any reliable figure, except those in Ly ell's Ele-
ments of Geology and in Woodward's Manual of the Mollusca. I hope my
identification to be correct, but if there should be a specific difference, it will
soon be found out by geologists, who have access to better libraries and muse-
ums than the city of Louisville offers to her scientists.

Formation and Locality. — In the Corniferous rocks near Louisville, in Kentucky and Indiana; of
exceedingly rare occurrence. The two specimens in my cabinet, as far as I know, are the only representa-
tives of this species in the seven or eight collections of the Falls Cities, as Louisville, Jeffersonville and
New Albany are often collectively named.

Fentamerus littoni. HALL.

Plate XXVII., figures 12 and 13.

Pentamerus littoni, Hall. Pal. N. YM Vol. 3, page 262.
Penlamerus littoni, Hall. 24th Kep. N. Y. St. Mus., p. 186—1872.
Pentamerus littoni, Hall. 27th Kep. N. Y. St. Mus., pi. 10, figs. 8 and 9—1875.

Shell ovoid, somewhat elongate. Dorsal valve moderately and regularly
convex from base to umbo ; beak strongly incurved under the beak of the
opposite valve. Ventral valve very gibbous ; beak sub-attenuate, incurved.

Surface marked by about eighteen to twenty and more simple, sub -angular
plications. There is a broad, concave, smooth space on each side below the
beak of the ventral valve, and a much narrower space on each side of the
dorsal valve. (Hall.) A large specimen of this species, in my cabinet, meas-
ures eleven lines in length, about the same in width, and nine lines in thick-
ness.

My figure is a copy of Prof. Hall's figure in the 27th Eeport. At the time
when my plates were made I had no fit specimen to copy, and Dr. Knapp's
shell was absent from the city. This species is associated with, and probably
related to, Pent, nysius.

Formation and Locality. — It occurs in the Niagara rocks near Louisville, Ky., where it is one of
the rarest species. At present my cabinet contains several fair specimens.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 53

Fentamerus nucleus. HALL.

Plate XXVII., figures 25 26 and 27, and Plate XXXIII., figures 27, 28, 29, 31, 32 and 33.
Pentamerus nucleus, Hall. 24th Rep. N. Y. St. Mus., p. 200a— 1872.
Pentamerus nucleus, Hall. 27th Rep. N. Y. St. Mus., pi. 9., figs. 30 to 32—1875.

Shell of medium size, sub-globose ; in the typical specimens width and
length about equal, but in the shells represented by figures 81, 32 and 33,
on plate 83, the length exceeds the width considerably. Ventral valve con-
siderably larger than the dorsal, and very ventricose ; cardinal margins
strongly rounded, forming, in most specimens, a regular curve, which joins
the somewhat stronger curve of the lateral margins. In some shells, however,
the cardinal margin is almost straight, equalling the greatest width of the
shell, and making the cardinal extremities either only slightly rounded or
obtuse angular, as may be seen in fig 31, plate 33. The umbo is very promi-
nent, and the beak strongly incurved over a small triangular foramen. The
middle of the valve, from below the umbo to the front, is slightly elevated,
forming a small mesial fold, and which consists usually of two, but sometimes
of three elevated plications. Dorsal valve transversely elliptical, or sub-oval,
only moderately convex ; umbo somewhat inflated. The middle of the valve,
below the umbo, depressed, forming a mesial sinus, which contains one or two
plications ; the beak is small and strongly incurved into the opposite valve.
Surface is marked by angular plications, usually two on each side of the mesial
fold or sinus ; these ribs do not reach very far back, never, or very seldom, ex-
tending beyond the middle of the valve, and in most specimens only noticeable
at and near the margin of the base. This species resembles somewhat Pent,
galeatus of the Lower Helderberg group, especially in those forms as repre-
sented by figure 31, plate 33, but it differs, in its shape and in the arrangement
of its plications, sufficiently from that species to be distinguished from it at the
first glance. It occupies an intermediate position between Pent, galeatus of
the Lower Helderberg, and Pent, fornicatus of the Clinton group. In regard to
the shells figured on plate 33, figures 31, 32 and 33, and even those figured on
same plate, figures 27, 28 and 29, I was uncertain for some time whether to
place them with this species or to refer them to Pent, galeatus. Since then I
found specimens of intermediate forms, uniting said shells with the typical
Pent, nucleus.

Formation and Locality. — These shells are found in the Niagara rocks of the quarries east of the
city of Louisville. Several good specimens were found by different collectors.

$0 PALEONTOLOGY OF KENTUCKY.

Pentamerus nysius, var. crassicostus. HALL.

Plate XXVIII., figures 5, 6, 7 and 8.

Pentamerus nysius, var. crassicostus, Hall. 24th Kep. N. T. State Mus., p. 184.
Pent, nysius, var. orassicostus, Hall. 27th Kep. N. Y. St. Mus., pi. 10, figs. 4 and 7—1875.

Shell large, at least above the medium size ; sub- triangular or sub-quadrate,
sometimes becoming obscurely trilobate ; length always, or mostly, exceeding
the width. Ventral valve gibbous ; greatest convexity below the umbo, from
where it curves gently to the front, and, at first slightly and later abruptly, to
the lateral margins from apex to the front. This abruptly bent portion of the
shell is always smooth. The beak is strong and pointed, and arched over a
large open fissure ; it is considerably elevated over the umbo of the other
valve. This valve has its surface divided, by two prominent concentric lines of
growth, into three zones, all of which are, however, covered by the radii. On
some of the shells belonging to this species these zones are not noticeable. The
dorsal valve is less convex than the other, it is depressed convex, with its
maximum convexity at the umbo, from where it slopes in a gentle curve to the
anterior and lateral margins. A strip on its lateral margins is abruptly bent
towards the ventral valve, and is not covered by radii ; the umbo is regularly
curved and reaching into the fissure of the opposite valve.

The surface is covered by single, strong and rounded plications, numbering
from twenty to twenty-five.

Formation and Locality. — Occurs somewhat abundantly in the Niagara rocks in the quarries east
of the city of Louisville, Ky.; but well preserved specimens are rather rare. In my own cabinet there are
some very perfect specimens of this species.

Pentamerus nysius, var. tenuicostus. HALL.

This variety agrees in every essential point with the preceding one, with the
exception of the radii. These are strong and coarse in the latter, and fine and
more numerous in the present variety. The number of costae never exceeds
twenty-five in P. crassicostus, while in P. tenuicostus it is about forty.

Formation and Locality. — Found associated with the preceding variety in the Niagara rocks easl
of the city of Louisville, Ky. ; somewhat rarer than the former.

Pentamerus oblongus. SO-WERBY.

Plate XXXIII., figures 16, 16 and 17.
Pent, oblongus, Sowerby. Murch. Sil. Syst., p. 641 — 1839.
Pent, laems, Ibrid. Iden, pi. 19, fig. 9.

Pent, oblongus, Hall. Geol. Rep. of 4th Dist. N. Y., p. 7—1843.
Pent, oblongus, Hall. Pal. N. Y., Vol. II., p. 79, pis. 25 and 26.

Shell sometimes very large, but very variable in size and form. It would be

DOSSILS OF THE SlLURlAft AND DEVONIAN BOOKS. 61

impossible to describe minutely every possible form of this species ; I shall,
therefore, limit myself here to the description of the forms occurring in the
vicinity of Louisville, which are represented on plate XXXIII. Shell of
medium size, longitudinally sub-elliptical or sub-quadrate ; somewhat gibbous
in the upper portion, but depressed-convex towards the front ; trilobate, the
middle lobe largely extending ; beak of the ventral valve elevated above and
incurved upon the umbo of the dorsal valve ; both valves almost equally con-
vex and their surface marked by concentric lines of growth, of which some are
very fine and scarcely noticeable, others, however, very strong and dividing the
surface into different zones. The beak of the dorsal valve incurves into the
other valve below its beak. All the specimens in my cabinet are casts ; some
of them show undoubtedly, though only faintly, traces of longitudinal striae
on the middle lobe of both valves.

An individual of average size has the following dimensions : length, two
inches and one-quarter ; width, one inch and three-fourths, and thickness about
one inch.

Formation and Locality. — Found in great abundance in the lower strata of the Niagara and in the
Clinton group, in Jefferson county, Ky., eastward from the city of Louisville. Though fractional shells of
this species are numerous, well preserved or even fair specimens are rare.

Pentamerus oblongus, var. cylindricus. HALL AND WHITFIELD.

Plate XXX., figures 2, 3 and 4.

Pent, oblongus, var. cylindricus, H. and W. 24th Kep. N. Y. State Museum, pi. 183 — 1872.
Pent, oblongus, var. cylindricus, H. and W. 27th N. Y. State Museum, pi. 10, figs. 13 and 14—1876.

Shell of medium size, sub- cylindrical in form; length exceeding the width
almost three times; very gibbous in the upper portion, gradually decreasing
towards the front. Ventral valve . a little more convex than the other; beak
elevated above and arched over the umbo of the other valve; greatest convexity
a little above the middle, from where it curves regularly towards beak and
front, but sloping abruptly, almost in a straight line, to the lateral margins.
The trilobate character of Pent, oblongus is very slightly noticeable. Dorsal
valve less convex and more regularly curved gently to beak and front, more
rapidly to the lateral margins ; beak incurved into the fissure of the other
valve below its beak. Surface of both valves is divided into different zones by
strong concentric lines of growth. The specimen figured measures in length
three inches ; in width one inch and three-eighths ; and in thickness a little
less than the width.

Formation and Locality. — Found in the Niagara and Clinton groups in Jefferson county, Ky., east
of the city of Louisville ; somewhat rare.

62 PALAEONTOLOGY OF KENTUCKY.

PentamerilS pergibboSUS. HALL AKD WHITFIELD.

Plate XXIX., figures 23 and 24.
Pentamerus pergibbosus, Hall and Whitfield. Pal. of Ohio, Vol. II., p. 139, pi. 7, figures 10 and 11—1875.

Shell of medium size, extremely and extravagantly gibbous •, proportionally
very elongate from beak to base, and very narrow ; the greatest width being
near the front, and equal to only about two-thirds the depth of the two valves
when united in the broader specimens, and in some extravagant cases even less,
while the depth of the united valves almost equals the length of the dorsal
valve. Beaks distant and strongly incurved, that of the ventral valve the most
prominent and narrower than the opposite. Ventral valve more than twice
as deep as the dorsal valve; most prominent at the umbo, from where it slopes
somewhat gradually towards the front margin; triangular foramen large,
higher than wide, partially filled by the beak of the opposite valve. Dorsal
valve more regularly arcuate than the ventral, almost evenly so, except for the
constrictions of the surface by lines of growth ; beak wide, strongly incurved
into the foramen of the other valve. Surface of the internal casts, in which
condition the specimens occur, strongly constricted by concentric lines of
growth, which are placed at irregular distances, and often dividing the surface
into several strongly marked transverse zones. The interior of the shell has
been characterized by large longitudinal septa, as seen by the cavities left in
the casts ; that of the ventral valve extending fully to or beyond the middle of
its length, while those of the dorsal valve reach about two-thirds of the length
of the valve, in all the specimens examined, and in one example almost to the
front margin, and vertically to the entire depth of the valve. The surface of
the shell, in its original condition, has been marked by fine radiating striae,
which are still visible on the casts of some individuals near the front of the
valves, although the most of them appear to be smooth except for the concen-
tric constriction. This species is most nearly related to Pent, occidentalis, Hall,
from the Onondago salt group, Gait, Canada West; it differs, however, very
materially from that one in the much greater depth of the dorsal valve, and also
in the relative thickness of the longitudinal septa, that one having them very
thick and strong; also in the finer striation of the surface. From Pent,
littoni, another closely allied species, it differs in being more extravagantly
gibbous, and narrower, and in being more finely striated. Copied exactly from
Hall & Whitfield' s description in the Ohio Report, Vol. II.

Good specimens in my possession show also faint radiating striae in the front,
still I doubt that the original shell was covered with radii. I have, for in-
stance, some specimens of Spir. radiata, which, on the larger portion of the
surface, retain the shell, while the front part is exfoliated. The shell-covered
portion shows no plications nor traces of them, while the exfoliated front is

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 63

plainly plicate, showing that striae or radii may have been obliterated from the
surface of the shell, even when internal casts bear undoubted evidence of their
existence. Pent, pergibbosus, as found in our quarries, a specimen of which is
copied on plate XXIX., can not be confounded with other species ; it must be
recognized at the first glance.

Formation and Locality. — Found in the middle strata of the Niagara rocks, in our quarries east of
the city of Louisville, where it is, however, exceedingly rare. I am not aware that, outside of the speci-
mens in my cabinet, and those formerly owned by Rev. H. Herzer, but afterwards acquired by Prof. Hall,
of Albany, N. Y., any others are in existence.

Pentamerus uniplicatus. N. SB.

Plate XXXIII. .figures 25 and 20.

Shell below medium size ; sub-triangular ; width exceeding the length ;
greatest width below middle of shell.

Ventral valve very convex or gibbous, having its greatest convexity a little
above middle of valve, from where it slopes in a moderate but regular curve to
the beak, and to the baso-lateral margins, but very abruptly to the cardinal
borders, which are broadly rounded; the baso-lateral margins are regularly
curved, and the front is slightly sinuate. The central portion of the ventral
valve is somewhat elevated, extending from beak to front, and forming a mesial
fold, which is narrow, and, in fact, not at all elevated above the general surface
of the valve ; its apparent elevation is due to two broad furrows, between which
it is situated. This mesial fold is flat on top, and has below the umbo a shallow
central depression. Umbo is prominent, and beak elevated and incurved. The
dorsal valve is moderately convex in the umbonal region, sloping from there
rapidly to the cardinal lines, near which it is slightly depressed ; towards the
baso-lateral margins dorsal valve becomes flat. The middle portion of the
valve from beak to front is depressed, forming a mesial sinus, which increases
in depth and width towards the front, and which is bounded on each side by
an obscurely marked plication ; this marginal rib is, however, only in the basal
half of the valve separated from the balance of the surface by a faint depres-
sion. The bottom of the mesial sinus is occupied by a low rounded plication,
which extends to umbo. The umbo is small, and the beak pointed and in-
curved. Outside of the ribs already mentioned, and some faint concentric lines
of growth, there are no other surface-markings indicated. Size of shell is
shown in illustration.

Formation and Locality. — The specimen here described and figured is the only one so far known to
me. I found it in the Niagara rocks east of the city of Louisville, Ky.

64 PALAEONTOLOGY OF KENTUCKY.

Pentamems ventricosus. Km-

Plate XXXIII., figures 12, 13 and 14. »

Pentamerus ventricosus, Hall. Geol. Kep. Prog. Wis., p. 2 — 1860.
Pent. (Pentamerella) ventricosus, Hall. 20th Keg. Kep., p. 374—1868.
Pent. (Pentamerella) ventricosus, Hall. Ohio Pal., Vol. II., p. 138—1875.

Shell of medium size, globose ; width and length about equal, sometimes a
little wider than long ; hinge-line short, and cardinal extremities rounded.
Ventral valve greatly more convex than the dorsal, with a very prominent
umbo, and a strongly incurved beak ; the middle of the valve marked by a
broad, moderately deep sinus, extending from beak to base, where it forms a
basal extension, deflecting upwards to meet a mesial indentation in the dorsal
valve. Dorsal valve most prominent at the umbo, from where it runs in a
straight line along the summit of the mesial fold to the front ; on both sides of
the mesial elevation there is a marked depression, formed by the mesial fold
and the markedly upwards turned lateral margins ; beak small and strongly
incurved into the opposite valve.

Surface of the shell is marked by concentric undulations of growth, which,
according to Prof. Hall's statement, are visible on the internal casts, but which
the specimens in my possession, being casts of the interior, do not show. In
my shells the surface is entirely smooth. Medium septum of the ventral valve
is very short. This species is easily recognized by its strong umbo and its
trilobed appearance in a front view. It differs from the ordinary forms of
Pentamerus in having the middle of its dorsal valve elevated in the form of a
mesial fold, while, in true Pentamerus, the middle of the dorsal valve is de-
pressed, forming a dorsal sinus, with a corresponding elevation on the other or
ventral valve.

Formation and Locality. — Found very rarely in the Niagara rocks of the quarries east of the city
of Louisville, Ky.

Genus Stricklandinia. Bmings.

Stricklandia, Billings. Can. Nat. and Geol., Vol. 4 — 1859.
Etymology : Named in honor of Prof. Strickland.

The name Stricklandia having been previously applied to a genus of fossil
plants, the author abandoned it and substituted Stricklandinia for it. This
genus includes such shells as Pentamerus lens, P. liratus, and P. laevis. They
differ from the real Pentamerus in having the valves usually sub -equal, and no
longitudinal septa or triangular chamber in the interior of the dorsal valve.
Both valves have an area, but in the dorsal it is usually linear, or slightly ex-
ceeding the thickness of the shell in height. The ventral valve has usually a

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 65

concave mesial sinus more or less developed, and the dorsal valve a mesial fold
corresponding thereto. Some of the species, as S. laevis and S. microcamera
have the hinge-line straight and much extended.

Stricklandinia louisvillensis. N. SP.

Plate XXXIV., figures 81, 32, 33 and 34.

Shell of medium size, sub-circular or sub-elliptical ; width greater than
length ; maximum width, below middle of shell, nearer to base than shown in
the figures 31 and 32; cardinal line straight on each side of beaks, but deflecting
somewhat to front ; shorter than the width of the shell, and its extremities
rounded ; lateral margins almost straight, or only slightly curved ; at their
basal termination the shell attains its greatest width ; basal margin broadly
curved, with the exception of its central half, which is somewhat produced, and
forming a broad but short linguif orm basal extension, giving the shell a some-
what trilobed aspect ; both valves are about equally convex, ventral umbo a
little more than dorsal ; umbones and beaks are so slightly developed as to give
only a very moderate angulation to cardinal line at its center. The hinge-
areas are almost concealed by the close approximation of the beaks; that of
ventral valve shows a narrow, almost linear strip along its rounded margins.
Neither of the valves shows the least indication of either mesial fold or sinus,
and the only point of distinction between the two valves is the umbo of the
ventral valve, which is slightly more convex than the dorsal, and which is also
a little elevated above the opposite beak. The surface is ornamented by seven
low, rounded plications on each valve, which start below the umbones and
extend, gradually increasing in strength and distance, to basal margin ; trans-
versely' they are limited to middle lobe of shell; lateral lobes and umbones are
entirely smooth or free from ribs ; this feature, and the three-lobate character
in the basal margin, are not sufficiently expressed in the figures, which also
show one rib too much. Of the seven plications on each valve, the central
three are considerably stronger than the lateral ones. The whole surface of
the shell is covered by fine, closely set, concentric striae of growth, of which
a few are slightly stronger than the balance, dividing the surface into several
concentric zones ; there are also radiating lines visible which are still finer than
the concentric striae. This shell bears some resemblance to Stricklandinia
davidsoni of Billings, as figured and described by him in his "Palaeozoic
Fossils, Vol. II.," but it differs from that species by having its greatest dimen-
sion transversely, while the other shell measures most longitudinally ; in our
specimen the middle lobe, or the basal extension, is broader in proportion to the
whole width of the front, but considerably shorter than that of Str. davidsoni ;
and the most prominent points of distinction are the plications, which in S.

GEOL. SUB. — 9

66 PALAEONTOLOGY OF KENTUCKY.

davidsoni are only faintly developed, but covering the whole surface, while in
our specimen the ribs are well marked and limited to the central lobe. The
specimen from which the illustrations are made is the only one so far known
to me ; it is a well preserved, beautiful shell.

Formation and Locality. — I found it in the strippings of one of the quarries east of the city of
Louisville, in clay belonging to the Niagara group, and associated with other well known Upper Silurian
shells ; I feel, therefore, fully assured that it belongs to the Niagara fossils.

Genus Chonetes. Fischer.

Chonetes, Fischer. Oryckt. Moscow — 1837.
Etymology : chone, a little cup.

Shell semi -ova1 or transversely oblong, with a wide straight hinge-line. Ex-
ternal margin of area of ventral valve furnished with a row of tubular spines.
Surface radiately striated, often spinose. Foramen in the ventral area distinct,
but partly closed by a pseudo-deltidium. Valves articulated by teeth and
sockets. Dorsal valve with a cardinal process, which is simple at the base,
but bifid or grooved at the extremity. Interior of the shell pustulose or papil-
lose. The genus Chonetes is nearly allied to Productus, from which it is dis-
tinguished by its articulated valves and row of tubular spines on the margin of
the ventral area, as well as by other characters of less importance. Unfortu-
nately the spines are often missing, having become obsolete by wear and rub-
bing. Even in the absence of these spines, Chonetes may be distinguished
from Producta by their less gibbous and ventricose ventral valve, and by their
finer surface striation. On the other hand, Chonetes, in form and external
appearance, makes an approach to the genera Strophomena and Leptaena, and
may be regarded as connecting link between the Sirophomenidae and Pro-
ductidae,

Chonetes acutiradiata. HALL.

Plate XVIII., figures 18, 19 and 20.

Strophomena acutiradiata, Hall. Geol. Rep. 4th dist. N. Y. — 1843.
Chonetes acutiradiata, Hall. Tenth Eep. on St. Cab., p. 117 — 1857.
Chonetes acutiradiata, Hall. Pal. N. Y., Vol. IV., p. 120—1867.

Shell of large size in its genus ; semi-circular ; sometimes more than twice as
wide as long ; the cardinal extremities produced and sometimes very mucro-
nate. Ventral valve moderately convex, sometimes a little gibbous in the
upper part, and frequently flattened or depressed at and below the middle;
greatest convexity a little above the middle, from whence it curves gently to
the front, somewhat abruptly depressed towards the cardinal extremities,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 6t

which are sub-auriculate and flat or slightly concave; umbo moderate, and
beak small and pointed, little elevated above the hinge-line, but perceptibly
incurved over ^the latter ; hinge-area small, but increasing towards the beak,
and concave. Dorsal valve concave, corresponding in its general form with
the convexity of the other valve ; hinge area, small and narrow, almost linear ;
no beak perceptible.

The surface of the ventral valve is covered by peculiar radiating striae,
which are strong, rounded or subangular, and simple in the umbonal region,
outside of which they bifurcate and increase also by implantation, but all
the striae on the marginal part are greatly finer than the umbonal ones ;
within the cardinal angles and along the cardinal margins the striae becomes
very irregular and often entirely obsolete. Hinge-line marked on each side
of the beak by four or five strong, tubular spines, which are directed obliquely
outwards. In the specimen before me, which completely agrees in all other
points with Prof. Hall's description, neither these spines nor any marks of
their former existence are seen ; it is possible they became obliterated by the
process of silicification.

Formation and Locality. — Found in the rotten hornstone in the upper strata of the Devonian for-
mation, at the Falls of the Ohio, on the Indiana shore of the river. Good or perfect specimens are ex-
tremely rare.

Chonetes subquadrata. x. SP.

Shell as chonetes of medium size ; sub-quadrate, hinge-line somewhat shorter
than the greatest width of shell ; cardinal extremities rounded ; lateral mar-
gins slightly curved, almost straight, except in their basal part, which is regu-
larly curved into the basal margin ; central half of front is straight or only
slightly curved.

Ventral valve only moderately convex in its central portion, which curves
regularly from its middle to apex and base ; the slope towards the lateral and
cardinal margin is more abrupt, causing a flattening of the valve along the
lateral borders, and producing between the cardinal extremities, which are a
little deflected, and the umbo, a shallow concavity ; umbo sharply defined,
and moderately elevated ; the beak small, pointed, and incurved over the
hinge-area ; the area is small, forming a low triangle, which is divided by a
small triangular fissure ; the foramen is partly closed by the cardinal process
of the opposite valve. The margins of the cardinal area are provided with two
round, tubular spines on each side of the beak, which appear from their
stumps to have an outward direction. The dorsal valve is concave, correspond-
ing in its depression with the convexity of the ventral valve ; its hinge-area is
narrow or linear.

The surface of both valves is covered by fine rounded, or sub-angular radi-

68 PALAEONTOLOGY OF KENTUCKY.

ating striae, which increase partly by intercalation but mostly by bifurcation
on the ventral valve, while it is the reverse on the dorsal valve, where very
few of the striae dichostomize, but a great many short ones are implanted.
The specimen before me, the only one so far known, measures seven and one-
half lines in width, live and one-half lines in length, and two lines in depth.
It differs from the other shallow Chonetes by its greater size, and from the
larger species by its shallowness.

Formation and Locality. — Found in the 'rotton hornstone in upper strata of the Devonian forma-
tion, at the Palls of the Ohio, on the Indiana shore of river.

Chonetes yandelliana. HALL.

Plate XVII., figures 16, 17, 18 and 19, and Plate XXXI., figures 20 and 30.
Chonetes yandelliana, Hall. Tenth Rep. on State Cabinet, p. 118 — 1857.
Compare : Chonetes lineata, ut sup., page 121.
Chonetes yandelliana, Hall. Pal. N. Y., Vol. IV., page 123—1867.

Shell very small, semi-oval, more or less gibbous ; hinge-line equalling the
greatest width of the shell ; cardinal extremities angular, but sometimes
rounded.

Ventral valve regularly convex, having its greatest convexity below the
umbo of the valve, from where it slopes in a regular curve to the lateral and
basal margins, but more abruptly to the cardinal angles, which are slightly
deflected, forming there a faint incurvation or concavity ; beak small and little
curved.

Dorsal valve corresponding in its concavity with the convexity of the ven-
tral, but owing to the internal cavity of the shell being somewhat less than
the ventral convexity. Cardinal area of the ventral valve parallel with the
longitudinal axis of the shell, nearly twice as wide in the middle than at its
extremities ; foramen comparatively large, with margins projecting and the
opening filled by the cardinal process of the opposite valve. Dorsal area
extremely narrow, being barely a denned line. Surface marked by fine, almost
equal striae, which increase by bifurcation and intercalation till there are from
sixty to seventy on the margin of the shell. The ventral valve has on its car-
dinal margin three to four short, oblique spines on each side of the center.
The interior of the ventral valve shows strong, dental lamellae, and the muscu-
lar impressions are pretty well defined. The dorsal muscular impression, are
also well marked, and between them there is a strong mesial ridge, which is
extended in a bidentate cardinal process. The lower half of the surface is
strongly papillose. This species bears a close resemblance to C. lineata, but
it is less gibbous, and not flattened on the middle of the ventral valve ; while
the interior presents more strongly defined markings. Generally three spines

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 60

are noticed on each half of the cardinal margin, but this is subject to varia-
tion, as the number may differ from two to four. Figure 19, plate 17, is
enlarged, and figures 19 and 20, on plate 31, show an elongate form.

Formation and Locality.— Occurs in the hydraulic limestone, in Jefferson county, Ky., and in
Clark county, Indiana, and is somewhat abundant in well preserved specimens. Prof. Hall named this
species in honor of the late Dr Lunsford Yandell, Sr., of Louisville, Ky., who was one of the first col-
lectors of fossils from the Falls of the Ohio.

Genus Productella. Han.

Productella, Hall. Pal. N. Y., Vol. IV., page 153—1867.
Etymology . Productella, diminutive of Productus.

Shell having the general form of Productus, but uniformly, with a narrow
area on each valve, a foramen or callosity on the ventral area, small teeth, and
more or less distinct teeth-sockets. The reniform vascular impression, rising
from between the anterior and posterior muscular impressions, curves gently
outwards, and following a curvature [somewhat parallel with the margin of the
shell to below the middle of its length, is abruptly recurved and the extremity
turned a little backwards, terminates about half way between margin and
anterior extremity of mesial septum. The cardinal process, seen from the
inner side, is bilobed, and from the exterior side each of these divisions is
usually bilobed. These shells differ from Stropholosia in the extremely narrow,
linear cardinal area, greater extension of hinge-line, more extreme arcuation
or ventricosity of ventral valve in many or most of the species, and especially
in the direction and termination of the reniform vascular impressions, which
resemble those of Aulosteges, and of some of Productus. It differs from Pro-
ductus by the constant presence of an area, hinge-teeth and sockets.

Productella subaculeata var. cataracta. HALL AND^WHITJ-IELD

Plate XVII., figures 6 to 9.

Productella subaculeata var. cataracta, H. and W. 24th Regent's Keport, p. 198 — 1872.
Productella subaculeata var. cataracta, H. and W. 27th Regent's Rep., pi. 9 — 1875.

Shell small, semi-globose, rounded; hinge-line straight and about equal to
width of shell; length and width of shell about equal. Ventral valve very
gibbous, regularly curved from umbo downward, and also transversely ; umbo
is considerably elevated above hinge-line, and the beak is small and incurved.
The lateral margins form with the cardinal line nearly right- angles; they are
a little contracted below the extremities, forming small ears ; below the ears
the sides are regularly curved, and the front is broadly rounded. The dorsal
valve is deep concave, as shown in the specimen illustrated on plate 17, figures
5 and 6. Said specimen is nearly perfect in both valves, and entirely free from

76 PALEONTOLOGY OF KENTUCKY.

rock. In this shell the dorsal valve shows a regular deep concavity, into which
the beak of the ventral valve overlaps.

The greatest depth of the dorsal concavity is about equal to half the length
of the hinge-line ; below the beak there is a slight impression into the umbo
of the other valve. The surface is ornamented by low, rounded, radiating
striae, reaching almost to the beak. My specimen, before alluded to, shows
real continuous plications, not mere isolated elevations above and near the
bases of each spine. Even the dorsal valve has faint indications of corres-
ponding striae. On these radii are placed at irregular intervals the long,
slender, round spines, with which the ventral valve is closely covered. These
spines are only indicated on the silicified internal casts by their scars, and on
better preserved shells, by their bases and short stumps ; they are only pre-
served in full length, where even the surrounding matrix became silicilied at
the same time with the shell. Concentric lines of growth are seldom noticed
on our shells.

Formation and Locality. — Occurs rather abundantly in the cherty layers superimposed upon the
hydraulic limestone of the Devonian formation around the Falls of the Ohio, in Jefferson county, Ken-
tucky, and in Clark county, Indiana, where it is usually found as silicifled casts of the interior. "Well
preserved shells, like that illustrated, showing both valves in perfect condition, with the exception of the
spines, are extremely rare.

Productella semiglobosa. ». SP.

Plate XXVI., figure 7.

Shell of medium size, semi-globose or sub-circular ; hinge-line somewhat
shorter than greatest width of shell; cardinal extremities rounded. Yentral
valve very gibbous, regularly curved from umbo to front, and also trans-
versely ; umbo only moderately elevated above surrounding surface ; beak
incurved upon hinge-line, not overlapping it into dorsal valve. Width and
length of shell about equal, but sometimes the width exceeding the length.
Dorsal valve apparently deep concave, but its other characters are not known.
Surface does not show any markings, except the stumps of a few isolated
spines placed at irregular intervals ; the figure 7, on plate 26, shows about
twice as many as in reality exist. I am unable to identify it with any of the
species of Devonian Productella known to me, and I, therefore, place it in
the above named new species. This shell has some similarity with some
middle-sized, but very ventricose forms of Strophodonta demissa, from which
it is, however, easily distinguished by its smooth surface, which shows only a
few spine-bases, while the Strophodonta demissa is covered by radiating striae,
and never becomes fully as ventricose as our shell. The specimen illustrated
is of about average size.

Formation and Locality. — Occurs in the Corniferous limestone at and around the Falls of the Ohio,
in Kentucky and Indiana. Only a few specimens are so far found.

Genus Leiorhynchus. Han.

Leiorhynchus, Hall. 13th Regent's Report — 1860.
Etymology : leios, smooth ; rhynchos, a beak.

Shell ovate, circular or transverse, with valves unequally convex, and marked
by mesial sinus and fold in the ventral and dorsal valves respectively. The
surface is plicated by rounded, bifurcating ribs, which are always more con-
spicuous on the mesial fold and sinus, whilst they often become obsolete on the
lateral portion of the shell ; concentrically marked by strong lines of growth.
Substance of the shell fibrous, usually thin. Valves articulated by teeth and
sockets ; the apex of the ventral valve perforate at some period of its growth,
the lower side being closed by deltidial plates. On the interior of the ventral
valve, two short diverging dental lamellae extend into and are joining the sides
or bottom of the rostral cavity; the muscular impression occupies a narrow
triangular or ovate triangular space, below the dental lamellae. The dorsal
valve has a well-defined septum, often reaching below the middle of the valve,
and divided above, leaving a triangular or spoon-shaped depression. The
hinge-plates are narrow, strong processes, with sockets embracing the teeth
of the opposite valve. (Hall.) This genus is closely allied to that of Rhyn-
chonella.

Leiorhynchus quadricostatus. VANVXKM.

' Orthis quadricostata, Vanuxem. Geol. Rep. 3d dist. N. Y., p. 186 — 1842.
Orthis quadricostata, Hall. Geol. Rep. 4th dist. N. Y., p. 223—1843.
Leiorhynchus quadricostata, Hall. 13th Rep on St. Cab., p. 86 — 1860.
Leiorhynchus quadricostata, Hall. Pal. N. Y.,.Vol. IV., p. 357—1867.

Shell of medium size ; broadly ovate ; from moderately convex to somewhat
gibbous ; with distinct mesial fold and sinus.

Ventral valve a little gibbous towards the beak; side nearly flat, with a
mesial sinus commencing below the umbo and extending to the front ; it in-
creases gradually in width and depth towards front ; umbo is of medium size,
and beak elevated and pointed, and slightly arched but not incurved ; place of
the apex appears to be occupied by a round perforation. Dorsal valve is more
convex than the opposite, having its greatest convexity in the middle of the
valve, from where it slopes in a light curve to the baso-lateral margins, and in
a stronger curve to the beak and cardinal margins. A mesial fold commences
to rise above the surface in front of the umbo, from where it slightly increases
in height and width towards the front. The dorsal umbo is low, beak small
and incurved. The surface is partly plicated. On the mesial elevation and in
the mesial sinus are generally 'four plications plainly visible in the basal half.

72 PALAEONTOLOGY OF KENTUCKY.

It appears that in the umbonal half of the shell only two plications existed
before they became obliterated, and that by bifurcation the four ribs were
produced, which now occupy sinus and fold. Some individuals have five ribs
instead of four. The lateral parts of this shell are often covered with several
faintly visible plications, but in most of the specimens these lateral ribs become
entirely obsolete, and the surface outside of sinus and fold is free from any
markings whatever.

Specimens of this species are seldom in a fair condition ; they are found in
the Genesee shale, and their shell being very thin, they become generally dis-
torted and compressed. The inclosing shale or slate did not possess sufficient
density and hardness to resist the pressure of the superimposed rocks, but
became compressed itself, and thus the imbedded shells suffered the same fate
as their matrix. I have found in the shales at the Falls of the Ohio, on the
Kentucky shore of the river, an almost perfect specimen of this species, with
a very slight distortion, and on the Indiana side I picked up another shell
belonging to L. quadricostata, not distorted at all, but a little defective at the
front, which, however, was easily restored ; and thus I possess two specimens
which show exactly the form and surf ace- markings of this species. Prof.
Hall states in his description of this shell, in Pal. N. Y., Vol. IV., page 358,
that on account of the compressed and crushed condition of the fossil, its real
form and its correct proportions could not be determined. The specimen before
me measures nine lines in length, nine and one-half lines in width, and five and
one-half lines in depth. Another specimen found at Lexington, Indiana,
measures thirteen lines in length, one inch in width, and seven to eight lines in
depth. These dimensions show that, in most instances, this shell has its width
and length about equal, while, its convexity may vary somewhat ; its greatest
width is either at the middle of the shell or a little below it.

Formation and Locality. — Found mainly in the Genesee shales, being the top strata of the Devo-
nian formation, at the Falls of the Ohio, in Kentucky, and at Lexington, Indiana, but some specimens are
also found in the rotten hornstone just below said shales.

Genus Rhynchonella.

Fischer.

Rhynchonella, Fischer. Mem. Soc. Imp., Mosc. — 1809.
Etymology : rhynchos, a beak ; ella, little.

Shells trigonal, acutely beaked, usually plicated, dorsal valve elevated in
front, depressed at the sides. Ventral valve flattened or hollowed along the
center; hinge-plate supporting two slender curved lamellae; dental plates
diverging.

The foramen is at first only an angular notch in hinge-line of the ventral

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 73

valve, but the growth of the deltidium usually renders it complete in adult
shell ; in the cretaceous species it is tubular. In some species the beak is so
closely incurved upon the other as to allow no space for a pedicle.
The Rhynchonella loxia is made the type of the genus Rhynchonella.

Rhynchonella acinus. HALL.

Plate XXVI., figures 6, 13 and 14, and Plate XXXII , figures 13 to 16.
Rhynchonella acinus, Hall. Trans. Alb. Inst., Vol. IV., p. 215—1863.

Rhynchonella acinus, Hall. 28th Rep. N. Y. St. Mus. Nat. Hist., Mus. edit., p. 163, pi. 26, figs. 7-11—1879.
Rhynchonella acinus, Hall, llth Geol. Rep. of Ind., p. 306—1881.

Shell very small, longitudinally ovate, sub-attenuate towards the beak and
truncate in front, valves sub-equally convex. Ventral valve sub-arcuate, flat-
tened in the middle, below which it is sinuate ; beak incurved. Dorsal valve
somewhat flattened in the middle, and sometimes a little depressed in upper
part of median line, two of the plications becoming elevated towards the front,
corresponding to an abruptly depressed sinus in ventral valve, in the bottom
of which is a single plication ; there are three and rarely four plications on
each side of mesial fold of dorsal valve, and four on each side of the sinus of
the ventral valve. Concentric lines of growth usually only faintly marked.
Length to width usually about as four to three, and depth about equal to
width, giving a sub-quadrate transverse section ; average size of the shell as
represented in the figures on plate 26.

This species differs from Rhyn. bidentata of Hisinger, in being larger, more
robust and .ventricose, and proportionally more elongate; the plications are
more rounded, and the whole aspect of the shell less angular. It approaches
in form the Rhyn. bialveata of the lower Helderberg formation, but it is
more robust, and the plications are more rounded. (Hall.)

Formation and Locality. — Found in the lower strata of the Niagara group in the quarries east of
the city of Louisville, Ky., but of rare occurrence. On some of the plates the two lower figures of this
species have no numbers. The side view should be number 13, and the front view number 14. This front
view shows in the mesial elevation three plications ; there should be only two.

Rhynchonella bellaforma. K. SP.

Shell of medium size ; sub -triangular or sub-pentagonal ; moderately convex,
rather somewhat compressed ; cardinal margins sloping down to the middle of
shell, and forming at the beaks an obtuse angle of about one hundred degrees ;
lateral margins short and strongly curved ; base only curved at the front
angles, the balance, about four-fifths of the whole front, almost straight, with
a slight emargination or inflection of its middle part. Width to length as
three to two ; greatest width below the middle.

Ventral valve moderately convex at the umbonal region, and near the cardinal
and lateral margins ; in front of the umbo the central portion of the valve

OEOL. 8UR. — 10

74 PALAEONTOLOGY OF KENTUCKY.

becomes depressed, which depression increases in depth, but more rapidly in
width, towards the base or front, which it occupies almost to the full extent of
basal length ; umbo is small, and the beak elevated and slightly incurved. The
dorsal valve is somewhat larger than the ventral, and also more convex ; it is
divided into two halves by a central depression, which extends f rom the beak
to a point below the middle of the valve, and which is most prominent in
umbonal region ; it is occupied by six single strong plications which reach
entirely back to apex.

The two outside of these six plications form the lateral limit of the depres-
sion, which ceases a little below the middle of valve, where the said six
plications become elevated above surface, and all six rising to the same level
extend to the front, where they form a mesial fold, which is entirely flat on top ;
the lateral , portion, of the valve outside of this mesial combination of sinus
and fold, is regularly and gently curved from beak to the lateral and baso-
lateral margins, while it slopes abruptly towards the cardinal lines, along which,
in both valves, the borders are inflected, meeting under a very obtuse angle,
but with its apex outward ; these inflected borders are entirely smooth ; the
umbo is small, also the beak, which is incurved into the other valve. The
surface is ornamented by strong, rounded, simple, radiating plications, of
which the ventral valve has seven in its mesial sinus, and five on each side of
it ; while the dorsal valve has six on its mesial fold and six on each side of the
same. All these ribs reach back to the beak, and are of about equal strength,
with the exception of the two outside ones on each side of the mesial fold and
sinus, which are smaller, and extend only for some distance back into the shell,
becoming obliterated by the smooth cardinal borders. No other surface-mark-
ings are observable. The specimen here described measures : length, six lines ;
width, nine lines ; depth, three lines. This is one of the most beautiful Rhyn-
chonella, as far as its shape is concerned, and for that reason I have named it
bellaforma. I do not know any species of its congeners to compare it with,
except, probably, Rhyn. tennesseensis of Roemer, but not with that form of
said species which Prof. Hall has, in late years, placed in the species of Rhyn.
stricklandi. To Rhyn. tennesseensis it has some resemblance, but differs from
it by its small depth, its being more transverse, its smaller and more numerous
plications, its cardinal borders, which are not as much inflected as in that
species ; in our shell the marginal angle at said borders has its apex outward,
while the same angle in Rhyn. tennesseensis_ has its apex inward. But the
most characteristic feature of our shell is its peculiar combination of mesial
sinus and fold on its dorsal valve, by which it is easily distinguished from any
other Rhynchonella.

Formation and Locality. — I found this interesting shell, finely preserved, in the Niagara clay, east
of our city. So far this one specimen only is known to me.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 75

Rhynchonella Carolina. HALL.

Plate XIII., figures 1, 2 and 3,"34 and 35,

Rhyn. Carolina, Hall. Pal. N. Y., Vol. IV., p. 337, pi. 34, figs. 14-19—1867.
Rhyn. Carolina, Meek. Pal. of Ohio, Vol. I., p. 196, pi. 18, figs. 8a-e— 1873.

Shell of medium size, trigonoid-subovate in general outline, moderately
gibbous, a little produced or widened in front. In an old shell of unusual size
belonging to my cabinet, the widening of the front portion is very consider-
able, so that the lateral margins, from beak to a little below the middle of the
shell, become strongly concave, while in younger specimens, those as figures 34
and 35, said margins are almost straight.

Ventral valve a little less convex than the other ; greatest convexity at the
umbo, from where it curves gently towards the front, and more abruptly to
the cardinal margins; beak prominent, little curved or nearly straight, and
elevated a little above umbo of other valve.

Mesial sinus starts a little above the middle of the valve, is broad, shallow
and flat at the bottom ; its margins are not well defined. Dorsal valve more
convex, moderately gibbous and regularly arcuate from summit to base, the
sides more abruptly curved ; mesial fold, beginning a little above middle of
valve, is broad, slightly convex, mostly flat, without well defined margins ;
beak strongly incurved into the other valve.

Surface is marked by from twenty-four to thirty simple, sub-angular, radi-
ating costae, of which from six to eight occupy the mesial sinus, and about
the same number the mesial elevation ; the ribs in the sinus and on the fold
are stronger than the lateral ones. The plications increase from the beak
towards the front in size and distance, and the lateral ribs are curving more or
less outwards. No other surface-markings are visible, not even concentric lines
of growth, on th« most perfectly preserved shells in my cabinet. This species
differs from all other rhynchonelloid forms of the Corniferous limestone, by
its broad, shallow and poorly defined sinus, as well as by its broad, flat and
also poorly defined mesial elevation, and by its more extended beak. Prof.
Hall is of the opinion that a larger material may hereafter prove its generic
distinction from Rhynchonella.

Formation and Locality. — Occurs in the Corniferous limestone at and near the Falls of the Ohio,
in Kentucky and Indiana. It is rather rare, though I possess in my cabinet a few exceedingly well pre-
served specimens retaining the shell entirely.

76 PALEONTOLOGY OF KENTUCKY.

Rhynchonella gainesi. N. SP.

Plate XXXI., figures 6, 7, 8, and 9.

Shell very small; sub- triangular ; length equal to greatest width, which
latter is near the base ; the cardino-lateral margins run in almost straight lines
from beak to point of greatest width; basal margin broadly curved, nearly
straight. Shell concavo-convex, and surface smooth except near the margins,
where faint plications are noticed. Ventral valve moderately convex at its
umbo, and in its upper one-third ; the balance deeply depressed to a sinus,
which occupies the whole width of the valve, and which is margined on each
side by the lateral margins of the shell, which deflect here downwards to a
sharp prominent point; sinus is flat in the bottom and extends considerably
beyond the base, forming a quadrilateral basal extension, which deflects at
right-angles upward to tit into a corresponding indentation in the dorsal valve ;
the height, measured between the highest point of the basal extension and the
apex of the pointed margins of the sinus, is almost equal to the width of the
shell ; the beak is elevated and slightly curved. Dorsal valve is somewhat
gibbous, with its greatest convexity at the middle of the valve, from where it
slopes in strong curves to the cardino-lateral and basal margins ; its central
portion runs in a straight line from the beak to the base, forming the mesial
fold, which becomes risible at a little above the middle of the valve, and in-
creases rapidly to the front or base, where it is very prominent ; umbo is
inflated, and the beak incurved into the opposite valve. The surface is en-
tirely smooth in its upper half, while the lower one shows some plications,
which are plainly visible at the basal margin, but do not extend far into the
shell. There are two faint indication, of plications on each side of the mesial
fold and sinus, while the mesial fold has three and the sinus two ribs on its
summit or bottom respectively. No other surface-markings are observable on
account of the silicification of the shell.

Formation and Locality. — Found in the rotten hornstone of the Devonian formation exposed in
several washes in Jefferson county, Ky. This pretty little shell is not very rare. This species is named
after Prof. J. T. Gaines, of Louisville, Ky., who, as ardent student and collector of fossils, deserves such a
recognition.

Rhynchonella indianensis. HALL.

Plate XXXIII., figures 18, 19 and 20.

Rhyn. indianensis, Hall. Trans. Alb. Inst., Vol. IV., p. 215—1863.

Rhyn. indianensis, Hall. 28th Kep. N. Y. St. Mus. Nat. Hist., Mus. edit., p. 163, pi. 26, figs. 12-22— 1S76.
Rhyn. indianensis, Hall, llth Geol. Rep of Indiana, p. 306—1881.

Shell small, broadly ovate or sub-triangular; length and width nearly equal,
or the former is sometimes slightly exceeded by the latter. Cardinal slopes in

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 7Y

the more gibbous specimens flattened. Ventral valve with the beak pointed
and incurved, depressed-convex in the middle, and gradually becoming
depressed and sinuate in front, two or three of the plications included in the
sinus. Dorsal valve a little the more gibbous, somewhat flattened in front of
the umbo. Three or four of the plications run straight from beak to front and
form a mesial elevation, the lateral plications are curving outwards to the
lateral margins. Each valve marked by from nine to twelve rounded or sub-
angular plications, which sometimes obsolete toward the beak. The concentric
lines are very obscure.

This species resembles the Rhyn. neglecta of the Niagara group of New
York, but it is larger and more robust, with stronger and more rounded plica-
tions. (Hall.)

Formation and Locality. — Found rarely in the Niagara strata in the quarries east of the city of
Louisville, Ky. Our specimens are smaller than the Waldron shells, and the plications on the Kentucky
individuals are less marked. They even become sometimes almost obsolete on the lateral slopes of the
Shell, and seldom extend as far back as the ribs on Waldron specimens. ,

Rhynchonellu, louisvillensis. K. SP.

Plate XXXI., figures 1 to 4.

Shell of less than medium size among the Rhynchonellidae ; longitudinally
sub -oval or sub-trigonal; length and width about equal, the latter rarely ex-
ceeding the former slightly ; both valves about equally convex.

Ventral valve moderately convex ; mesial sinus beginning in front of the
umbo, is broad and flat, deepens at the base, and has a considerable quadri-
lateral extension, fitting in a corresponding indentation of the other valve ; it
contains five plications ; beak small and pointed, and only slightly arched.
Dorsal valve somewhat more convex than the other ; mesial fold starting below
the umbo, and becomes prominent at the front, and contains, like the sinus,
five plications ; beak small, narrow, and incurving into the other valve beneath
the ventral beak.

Surface is ornamented by four or five rounded ribs on each side of the mesial
depression or elevation; those on the lateral slopes of the dorsal valve are
abruptly curving outwards and downwards. In regard to measurement, the
figures on plate 31 give the dimensions of an average-sized specimen.

Formation and Locality. — Found in the Corniferous rocks surrounding the Falls of the Ohio, in
Kentucky and Indiana, where it is, however, of rare occurrence. As far as my information goes, only
three individuals of this species are known. This species has some resemblance to Hall's Khyn. indianensis
of the Niagara group, but it is easily distinguished from that species, differing from it by its larger number
of plications in the sinus and on the fold, by the greater extension of its mesial fold, and also by its
greater convexity or gibbosity.

78 PALEONTOLOGY OF KENTUCKY.

Rhynchonella pisa. HALL AND WHITFIKLD.

Plate XXXII., figures 24 to 27.
Rhynchonella pisa, H. and W. Pal. of Ohio, Vol. II., p. 135—1875.

Shell small, globular in full-grown specimens, but varying from depressed
lenticular to highly gibbous at different stages of growth. Gfeneral outline of
the shell broadly ovate, widest near the front or below the middle of the
length. Ventral valve less gibbous than the dorsal ; beak small, pointed and
slightly curved, usually projecting but moderately beyond that of the opposite
valve, though sometimes rather extended ; body and sides of the valves regu-
larly rounded, becoming broadly but not deeply sinuate in front, where it is
prolonged and bent upward in the middle. Dorsal valve regularly convex,
center of the valve most prominent, becoming slightly elevated in front, form-
ing a not very prominent mesial elevation. Surface marked by from twelve to
sixteen rounded plications, which are distinctly marked on sides and in front,
but becoming obsolete soon after reaching the middle of the valve on the dorsal
side, but are continued somewhat further on the ventral valve, and in some
specimens those bordering the sinus extend to near the beak. On the dorsal
valve there are usually four plications elevated to form the mesial fold, and
three depressed in the ventral sinus, though in some cases there are only three
elevated on the dorsal valve. This species resembles Rhyn. neglecta, with
which it is associated, but differs in its general convexity of the valves and
want of angularity in the plications, which do not extend to the beak as in
that species. The more elongate forms have some similarity to Rhyn. acinus,
but have not the flattening of the sides and surfaces of the valves, as in that
species, and have, moreover, a greater number of plications. The more ventri-
cose forms resemble, very closely, small specimens of Rhyn. nucleolata, but,
besides being more elongate, with a more projecting beak, the plications are
never flattened on their surfaces, and .are destitute of the groove along the
middle, as in that one. (Hall and Whitfield.)

Formation and Locality. — Occurs in the Niagara rocks of the quarries east of the city of Louis-
ville. It is a rather rare species. The specimen illustrated on plate u32 is of about the largest size this
species ever attains.

Rhynchonella rugaecosta. K. sr.

Plate XXXII., figures 48, 49, 50 and 51.

Shell of medium size, sub-triangular or sub-pentagonal ; compressed or very
moderately convex ; width to length as three to two.

Ventral valve moderately convex in the umbonal region, sloping from there
in a straight line to the baso -lateral margins, but rapidly, almost abruptly, to

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. V9

the cardinal borders ; in the middle part of the valve is a mesial depression,
which extends from beak to base, and increases in depth and width only mod-
erately towards the front ; the umbo is inflated, and the beak elevated, pointed
and only slightly arched.

Dorsal valve moderately convex only at the umbo, balance only slightly
curved, almost flat ; middle of valve is elevated from beak to front, forming a
well defined, but narrow and little elevated mesial fold, at the base of which
the front- margin is slightly sinuate.

The surface is ornamented by simple sub-angular radiating striae, of which
four to five on each side of the mesial fold and sinus are more prominent, and
reach from the baso-lateral margins back to the beak ; they are, however, only
faintly marked in the umbonal region of each valve ; above these principal ribs
there are about four short ones on each side of the mesial fold and sinus, ter-
minating in the cardinal margins, the uppermost not more than about a line
from the dorsal beak. The illustration does not show this peculiar feature,
except in the side-view, where it is faintly indicated. These radii are crossed
by concentric lamellose, imbricating striae, which become crowded towards the
front, and which produce the rugose appearance of the shell. The specimen
before me measures six lines in width, four in length, and three in depth.
There are no plications on the fold nor in the sinus. This species is easily
distinguished from all other Rhynchonella.

Formation and Locality. — Found in the upper strata of the Niagara group, in the quarries east ot
the city of Louisville. It is of rare occurrence.

Rhynchonella saffordi. HALL.

Plate XXVII., figures 22. 23 and 24, and Plate XXXIII., figures 4, 5 and 6.
Rhynchonella saffordi, Hall. Can. Nat. and Geo., Vol. V., .Niag. group — 1860.
Rhynchonella saffordi, Hall. 27th Kep. N. Y. State Mus., pi. 9, figs. 27-29—1875.

Shell somewhat below medium size, varying from ovate to spherical, sub-pen-
tagonal, having the five sides almost equal, the front or base generally a little
larger than the lateral margins and the slopes of the beak ; shell very gibbous.
Ventral valve convex or depressed-convex, greatest convexity a little below
the umbo, from where it curves gently towards the lateral margins, but before
reaching these, it deflects very abruptly, almost forming here a right-angle ;
beak small and little arched, and slightly elevated above the one of the other
valve ; umbo scarcely noticeable. In the upper part of the valve, from apex
to one-third of its length, there is a slight elevation in the middle ; from the
point where this elevation ceases, some of the central plications become de-
pressed, which depression is only very slight but increases towards the front ;
here the depressed part of the valve makes a sudden and abrupt, almost angu-

80 PALEONTOLOGY OF KENTUCKY.

lar bend, in the dorsal direction. The number of depressed plications is very
variable, running from three to nine ; the deflected front part of the valve is
quadrilateral, its length sometimes exceeding its width ; its deflection amounts,
usually, to ninety degrees, but it sometimes exceeds the right-angle a few
degrees.

The dorsal valve is very gibbous, having its greatest convexity a little below
the middle of the valve, from where it curves regularly and gently to the front
and rear, but very abruptly to the lateral margins ; there is a slight depression
in the middle of the valve from apex almost half-way down or even a little
further. Where this depression terminates some of the central plications,
from five to ten in number, commence to rise, increasing in elevation towards
the front, forming here a kind of mesial elevation. This valve has in its front
part a quadrilateral indentation, corresponding in form and size to the front
extension of the ventral valve, which fits into it exactly. The base of the
shell forms a regular quadrangle. The surface is covered by fine radiating
plications, rounded or somewhat flattened, some of which bifurcate ; they
differ in size and number, which latter runs from twenty to thirty. Two some-
what different forms of this species are found, as represented by the figures in
the two different plates ; the group represented on plate 27 is somewhat longer
than wide, and its plications are less in number, and markedly coarser, while
the shells figured on plate 33, are wider than long, with finer and more numer-
ous plications; but there are so many specimens of intermediate forms con-
necting the two groups, that I feel not justified to separate them as different
species or varieties.

This species differs greatly in size in different specimens ; one of average size
has the following dimensions : width, seven lines ; length, eight lines, and
thickness, from six to seven lines.

Formation and Locality. — Occurs somewhat abundantly in the Niagara rocks in the quarries east
of the city of Louisville, Ky., where even well preserved specimens are not rare. This species was
named by Prof. Hall after Prof. Safford, of Nashville, Tennessee, formerly State Geologist of Tennessee.

Rhynchonella saffordi var. depressa. K. VAR.

. Plate XXXIII., figures 1, 2 and 3.

Although this shell agrees in so many points with Rhyn. saffordi, to place it
with that species, it, on the other hand, possesses some very important features
which separate it from saffordi, and which I think justify me to make a new
variety out of it. These features are as follows :

1. This shell is very flat or compressed, more so than any other Rhyncho-
nella of its size, while Rhyn. saffordi is generally very ventricose.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 81

2. The elevation and depression of the central plications are scarcely notice-
able in this shell.

3. The beak of the ventral valve is more pointed, and elevated above that of
the other valve. One of my specimens of this species shows faint traces of
very fine radiating lines, also of fine concentric striae or lines of growth ; both
these lines, the radiating and the concentric, may also be found in more per-
fect specimens of Rhyn. saffordi, though none among the many shells of that
species in my collection show them.

Formation and Locality. — Associated with Rhyn. saffordi in the Niagara rocks in the quarries east
of the city of Louisville, Ky., but of rare occurrence.

«

Rhynchonella Strickland!. SOWKRBY.

Plate XXV1L, figures 9, 10 and 11, and Plate XXIX., figures 3 to 6.
Terebratula Stricklamli,, Sowerby. Sil. Syst., pi. 13, fig. 19—1839.
Rhyn. Tennesseensis (Koemer), Hall. Trans. Alb. Inst., Vol. IV.
Rhyn. Siricklandi, Hall. 28th. Kep. N. Y. State Museum— 1876.
Rhyn. Stricklandi, Hall, llth Geol. Kep. of Ind., p. 308, pi. 26—1881.

Shell one of the large-sized Rhynchonellidae, sub-ovate or sub-trigonal; width
sometimes equal, but mostly exceeding the length ; sides and front rounded ;
shell almost concavo-convex. Surface plicate.

Ventral valve regularly curved from beak to front j the mesial sinus, which
commences below the umbo, occupies, from that point to the front, the largest
portion of the valve ; it is shallow at the beginning, but deepens approaching
the front. On each side of the sinus are five plications smaller than those
occupying the mesial depression ; in the most lateral plication the margin of
the valve makes a very abrupt bend, equalling . or exceeding ninety degrees
towards the dorsal valve, forming here a smooth, vertical border ; beak small
and incurved over the umbo of the other valve. The sinus contains usually
nine strong, simple and rounded plications ; the whole valve has from eighteen
to twenty of these ribs, which increase in size and distance from beak to front ;
most all of them reach to the front, only a few appear to be somewhat shorter.
Dorsal valve is very gibbous or ventricose, slightly flattened at the umbo ;
mesial fold not defined on the umbo ; from there it becomes gradually more
elevated as it approaches the front, where it is more or less prominent. The
fold has generally four plications on top and three on each of its slopes ;
outside of the mesial elevation, each side of the valve contains four plications,
thus covering the whole valve with about eighteen ribs ; those on the fold are
somewhat stronger than the lateral. In the last lateral plication the surface of
the valve bends abruptly towards the ventral valve, forming here, like the latter,
a smooth border of considerable size. All the ribs are roundect and simple,

OEOL. SUR. — 11

82 PALAEONTOLOGY OF KENTUCKY.

and increase in size and distance from beak to front. The ventral valve has
its mesial depression greatly produced in front, and abruptly turned upwards,
which extension fits exactly in a corresponding indentation in the base of the
dorsal valve. There are no radiating striae visible, but a few concentric lines
of growth may be noticed. The shells of this species were originally identified
with Rhyn. tennesseensis, a species described by Prof. P. Roemer, of Germany,
from the Silurian of Tennessee, and they are, therefore, generally known
under that name. A closer examination and comparison showed the former
identification as erroneous, and placed our shells in their present species.

Formation and Locality. — This species occurs in great abundance and in fine and well preserved
specimens in the Niagara rocks at Waldron and St. Paul, in Indiana; in the Niagara strata of Kentucky,
near to and east of the city of Louisville, this species is also found, but very rarely, and then in defective
and distorted specimens. The best individual, so far as I know, ever found in our quarries, is figured on
plate 27; it is considerable smaller than the Waldron shells, but has their exact form and markings. An-
other specimen which I found associated with the former, has the same shape in its outlines, but shows only
faint traces of the plications ; its surface appears almost smooth.

Rhynchonella tenuistriata. N- BP-

Plate XVII., figures 27, 28 and 29.

Shell rather small, sub-triangular or sub-pentagonal ; cardinal line forms a
right-angle at the beak; its two sides, which are somewhat concave or in-
curved, slope down below the middle of the shell ; here they meet the lateral
margins, with which they form again an almost right-angle; lateral margins
short, about one-third the length of the shell, almost straight or very slightly
convex ; basal margin straight, with a slight concavity.

Ventral valve less convex than the dorsal, with its greatest convexity at the
umbo, from which it slopes in almost straight lines to the lateral margins ; the
cardinal margins deflect abruptly upwards to meet the margin of the dorsal
valve in one and the same plane ; below the umbo the central portion becomes
depressed, which depression increases in depth and width towards the front,
where it occupies the ralve to the full extent of the basal margin. This mesial
sinus is rounded, its margins are not well defined, and its depth becomes only
somewhat prominent at or near the front ; the umbo is small, the beak elevated
above that of the other valve, and very little arched. The dorsal valve very
little convex, almost flat in the umbonal region and below it to the basal mar-
gin, where a part of the front is elevated into a mesial fold. On each side of
this mesial fold the valve slopes down very abruptly to the baso-lateral mar-
gins. The mesial fold is only observeable at or near the front ; the umbo is
inflated, and the beak small and incurved into the opposite valve. The surface
of both valves is covered by slender, sub-angular or rounded radii, of which
there are five or six on each side of the mesial fold and sinus ; the fold is

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 83

occupied by about seven, while the sinus only contains about six. These striae
increase by intercalation, but not by bifurcation. Other markings of the
surface are not observed.

Formation and Locality. — Occurs very rarely in the Corniferous rock of the Devonian formation
in Kentucky and Indiana.

Rhynchonella tethys. BILLINGS.

Plate XIII., figures 25 to 33, and Plate XXXI., figures 22 to 25.
Rhynchonella tethys, Billings. Canadian Journal, p. 270 — 1860.
Rhynchonella tethys, Hall. Pal. N. Y., Vol. IV., p. 335—1867.

Shell of medium size among ths Rhynchonellidae, sub- trigonal ovate, usually
wider than long, but sometimes length and width equal. Ventral valve de-
pressed convex in the upper part, nearly flat at the sides; sinus, beginning
above the middle, moderately depressed in young shells, and in older ones
becoming deep in front and abruptly curving towards the dorsal valve. Dorsal
valve moderately convex in young shells, more convex and finely gibbous in
old shells ; the broad mesial elevation becoming distinct about the middle of
the length. Surface marked by from fifteen to eighteen angular plications,
of which four to six are upon the mesial fold, and three to five in the median
sinus, while about five or six cover the lateral slopes of each valve on each side
of the mesial fold or sinus ; plications outside of fold on dorsal valve curve
very abruptly outwards as well as downwards. Fine concentric striae, which
are undulated in crossing the plications, mark surface of shell, but this feature
is rarely preserved.

Formation and. Locality. — Found abundantly and in well preserved specimens in the Corniferous
rock at and around the Palls of the Ohio, however, all the shells found are in a silicified condition, by
which, generally, the finer surface-markings become obliterated. If we compare the shell figured on plate
31 with those on plate 13, it appears to us that it does not belong to the same species. The shell on plate
31 has its plications finer and rounded, and its mesial elevations and depressions less prominent; it has six
ribs on the fold and five in the sinus. The shells on plate 13 show four to five plications on the fold, and
three to four in the sinus; all the ribs are coarse and angular. But if we compare the different shells in a
large lot of from fifty to sixty individuals, as are now before me, it is impossible to draw a dividing line;
there are numerous intermediates connecting the two extreme forms, which must, therefore, be classed in
one and the same species,

Rhynchonella increbescens. HALL.

Plate XXXIV., figures 26-29.
Atrypa increbescens, Hall. Pal N. Y., Vol. I., pi. 33, p. 146—1843.

Average shell small, ovate-trigonal, full-grown specimens quite convex, with
slightly greater width than length. Cardinal slopes nearly straight in young

84 PALEONTOLOGY OF KENTUCKY.

examples, slightly curved in adult specimens, anterior margins rounded to the
front.

Dorsal valve greatly convex, particularly towards the front, approaching
which the mesial ridge is greatly elevated (especially in more globose speci-
mens), and is gathered into four plications. The sides radiate from beak in
five or six plications, strongly curved towards the anterior lateral margins.

Ventral valve is depressed from beak to anterior central region, where it
curves more strongly. A mesial sinus begins at beak, has sloping sides, three
plications, and diverges to a great width at the front, where it terminates in an
extended, half -circular, marginal projection corresponding to, elevation in the
front of the dorsal valve. The sides radiate to the anterior margins in five or
six plications rounding towards the front.

The beak of the ventral valve is curved so as to hide the apex of the dorsal
valve. The angular plications and furrows give the margins a distinct zigzag
outline; the larger specimens show several lines of growth, more distinct
towards the front, crossing the plications and furrows.

In the specimens before me the plications in the lateral slopes vary ; some are
imperfectly developed and almost indistinct. The plications in the mesial sinus
and elevation never vary. The smaller specimens are generally more com-
pressed and the larger more rounded in outline than the typical forms.

Formation and Locality. — This shell seems to be confined to the Upper Trenton, where it is found
quite abundantly, and associated with Orthis borealis. It occurs in most of the blue-grass counties of the
State. The specimens figured are from Frankfort, Ky.

Genus Rhynchotreta.

Rhynchotreta, Hall. 28th Regent's Report — 1879.
Etymology : rhynchos, beak ; tretos, with a hole in it.

Type : Rhynchonella cuneata, Dalman.

Shell triangular ; surface with angular plications. Ventral beak straight,
produced beyond the dorsal beak, extremely perforated; foramen with an
elevated margin ; space between the foramen and hinge-line occupied by a del-
tidium in two pieces, being divided by a longitudinal suture, and transversely
striated. Valves articulated by two slender, curving teeth, proceeding from a
broad curving hinge-plate in the ventral valve, which fit into corresponding
sockets in the dorsal valve. Crurae rising from near the dorsal beak, and curv-
ing into the ventral cavity, and thence recurved towards the dorsal side, and
probably uniting. Structure fibrous, and apparently yery minutely punctate.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 85

Rhynchotreta cuneata, var. americana. HALL.

[Plate XXXII., figures 58, 59, 62 and 63.

Rhynchotreta cuneata, var. americana, Hall. 28th Rep. N. Y. State Museum, Nat. Hist. Mus., p. 167 — 1879.
Rhynchotreta cuneata, var. americana, Hall, llth Geol. Rep. of Indiana, p. 310, pi. 25, figs. 29-38 — 1881

Shell triangular, cuneiform, longer than wide, greatest width near the froni
and tapering posteriorly into an angular beak. Valves moderately convex,
the dorsal sometimes gibbous, ventral beak elongated, foramen sub- circular,
formed by the extremity of the beak, and a portion of the area below, which
is separated from the hinge- line by a deltidium in two pieces ; sides of the
beak compressed, flat or concave. Sinus wide, deep or shallow, according to
development of shell, commencing at one-third the length of shell from beak,
and becoming very conspicuous in front.

Dorsal valve the more convex, the mesial fold beginning as a depression just
below the beak, and becoming very prominent on lower half of shell. Surface
marked by nine or ten strong angular plications on each valve, of which three
are depressed in the sinus, and four are elevated on the mesial fold, the two
central ones being much the more prominent; the plications are crossed by
numerous regular thread-like striae. The entire surface is minutely papillose.
(Hall.)

Formation and Locality. — Found in the Niagara strata east of the city of Louisville, Ky. There
it is, however, extremely rare, and the few specimens found are not well preserved, and show, besides, that
the condition of our Niagara ocean did not favor their development, which appears to have been poor.
Numerous, originally well developed, and afterwards well preserved specimens of this species come from
Waldron, Indiana. In that locality the Niagara sea must have afforded conditions most favorable to the
development of its rich molluscan fauna. If we compare this species with its European congener, we find
our shell more robust and larger, and its surface is marked by fewer and stronger plications ; while the
transverse striae are a little finer and less distant, and the sinus is much deeper and more abrupt. The
figures on plate 32 are copied from Hall's 28th Report. My own specimens from our locality were not
sufficiently preserved to be used for figures.

Genus Ambocoelia. Haii.

Shell bivalve, inequivalve, equilateral, plano-convex or concavo-convex ;
valves articulated by teeth and sockets ; cardinal line equalling the greatest
width of the shell. Area common to both valves ; foramen triangular, extend-
ing also to the area of the dorsal valve. Dorsal valve flat, depressed convex or
concave ; cardinal process bifurcate. The foveal plates are straight, longitudi-
nal, pointed at their inner extremities, and from their center on the outside
extends a callosity curving around the dental sockets, which open towards the
cardinal line. Muscular impressions four, and distinctly marked in the middle
of the valve or below. Ventral valve arcuate, with or without a distinct sinus ;

86 PALEONTOLOGY OF KENTUCKY.

beak arching over the area ; dental lamellae strong, extending in short, obtuse
teeth. The impressions of the cardinal muscles form two semi-oval pits near
the middle of the concavity between the beak and base of the shell. Surface
very finely cancellated by obscure, radiating striae and fine concentric lines of
growth. Shell-structure fibrous or fibro-punctate ; luster pearly. The typical
species is Ambocoelia umbonata of Conrad.

Ambocoelia umbonata. CONRAD.

Plate XVII., figures 26 and 26.

Orthis umbonata, Conrad. Jour. Acad. Nat. Sci., Phil., Vol. 8.
Orthis umbonata (Conrad), Hall. 10th Rep. on State Cab., p. 167—1857.
Ambocoelia umbonata, Hall. 13th Kegent's Rep., p. 71 — 1860.
Orthis nucleus, Hall. Geol. Rep. 4th disk, pp. 180 and 181.
Ambocoelia nucleus, Hall. 13th Regent's Rep., p. 71.
Ambocoelia umbonata, Hall. Pal. N. Y., Vol. 4, p. 259—1867.

Shell very small, plano-convex, sub-circular ; length and width in our speci-
mens about equal ; hinge-line equal to the greatest width of the shell ; cardinal
extremities either obtuse-angular or rounded.

Ventral valve gibbous, with the umbo extremely elevated, and a compara-
tively large incurved beak ; mesial sinus distinct, extending from the beak to
the front; it is shallow and rounded at the bottom ; its margins are also
rounded and not defined ; the cardinal area is rather large in proportion to the
small size of the shell ; its margins are sharply defined ; it is strongly concave,
and has a large triangular fissure in its center ; the beak is prominent and
strongly incurved into the upper portion of the foramen.

Dorsal valve semi-elliptical, depressed convex in the upper central portions,
concave below the middle and at the sides ; apex scarcely elevated above the
hinge-line ; area very narrow and almost linear ; there is no indication of any
kind of a mesial fold.

Surface marked by very fine radiating and concentric striae, the latter some-
times becoming crowded, lamellose and imbricating towards the front of the
valves. In the shells of our rocks these surf ace- markings are not visible, they
became obliterated by the silicification of the specimens.

Formation and Locality. — Occurs in the rotten hornstone of the Devonian formation, in Jefferson
county, Ky., and is mainly found in some washes east of the city of Louisville, where it occurs in great
abundance, but of considerably smaller size than eastern specimens of the same species.

87

Genus Athyris. Mccoy.

Athyris, McCoy. Carb. foss. Ireland — 1844.
Etymology : a, without; thuris, a small door, in allusion to the absence of a deltidium or door.

Shell variable in shape ; valves unequally convex, with or without a mesial
sinus and fold ; articulated by teeth and sockets. Beak of ventral valve in-
curved, usually overlying and in contact with beak of the dorsal valve, and
perforated by a foramen, or, when old, the foramen fully concealed. In the
interior of ventral valve the dental plates are fixed to and along the sides of a
longitudinal prominence or convex arch- shaped place, which extends to less
than a third of the length of the shell, with its narrow end fitting into the
extremity of the beak, and its lateral diverging edges to bottom of valve. The
interior of the dorsal valve is partly divided by a large, deep, longitudinal
septum, which extends from the extremity of the umbo to about two-thirds of
the length of the shell, supporting at its origin the hinge-plate, which is
divided into two portions by a narrow, gradually widening channel. To the
socket ridges are affixed the spiral cones, the extremities of which are directed
towards the lateral margins of the shell ; on either side of the septum are seen
two muscular scars formed by the adductor.

Athyris vittata. HALL.

Plate XVI., figu-es 25-32.

Athyris vittata, Hall. Thirteenth Eep. on State Cab., p. 89—1860.
Compare Athyris concentrica ; A. spiriferoides.
Athyris vittata, Hall. Pal. N. Y., Vol. IV., page 289, plate 46—1867.

Shell sub-circular or sub- quadrate ; gibbous ; hinge-line short, with cardinal
extremities rounded ; front conspicuously sinuate.

Ventral valve gibbous above, more convex than dorsal valve ; umbo promi-
nent ; the beak incurved and truncated in the plane of the longitudinal axis
by a round foramen ; curving very abruptly to the cardinal and lateral mar-
gins ; the center, marked by a mesial sinus which extends nearly or quite to
beak ; it is shallow, deepening and widening towards the front ; its margins
are not defined but rounded and coalesce with the surface of the valve ; it has
a considerable basal extension, which is abruptly bent upwards and fits into
a corresponding indentation of the other valve. Dorsal valve a little less gib-
bous than the ventral one ; sides regularly curving from the umbo ; about the
middle of the valve an elevation commences, which increases towards the front,
where it is of considerable height, thus forming a conspicuous mesial fold ; the
beak is strongly incurved into the other valve below its beak,

88 PALAEONTOLOGY OF KENTUCKY.

Surface marked by regularly imbricating lamellose lines of growth, which,
on the surface of well preserved specimens are finely crenulate on their edges
and the intermediate spaces striate. In most of the specimens found the sur-
face is entirely smooth, with the exception of a small strip around the lateral
and basal margins, where the lines of growth are not obliterated by the silicifi-
cation.

Formation and Locality.— Found in great abundance and in well preserved specimens in the Cor-
niferous limestone at and around the Palls of the Ohio, in Kentucky and Indiana. In some washes of the
fields around Charlestown the ground is, after some hard rains, literally covered with these pretty little
shells. This species bears in its outlines the greatest resemblance to Athyris concentrica of Europe, with
which it is undoubtedly nearly related, but it may be easily distinguished from that species by not having
the fine concentric lines which are so conspicuous in the European species. From Athyris spiriferoides it
differs partly in shape, and, according to Prof. Hall's statement, mostly in internal features. Specimens
are found showing the internal spiral coils splendidly preserved. The figures 25 and 31, on plate 16, do
not~show plainly enough the round foramen or perforation in the beak of the ventral valve,

Genus Atrypa. Daiman.

Atrypa, Daiman. Vet. Acad — 1827.

Etymology: a, without; trypa, a hole.. Daiman supposed that this shell had no foramen beneath the beak,

which it has ; A is, therefore, a misnomer.

Shell inpunctate and fibrous ; surface often or usually ribbed, and often fur-
nished with imbricating lines of growth, often produced into foliaceous ex-
pansions ; valves articulated by teeth and sockets ; the ventral valve often
depressed in front, with or without a mesial sinus ; its beak incurved and
perforated at the apex by a minute foramen, which is sometimes bounded in
front by a deltidium. Dorsal valve convex and often very ventricose, with
or without a mesial fold ; the hinge-plate divided and supporting two large
conical spires, which are directed into the hollow of the dorsal valve.

Atrypa aspera. SCHLOTHEIM.

Plate XI V., figures 1 to 11.
List of synonyms, see Hall's Pal. of New York, volume 4, page 322.

Shell of medium size ; sub-circular or oval, moderately convex ; length and
width almost equal ; hinge-line shorter than width of shell ; cardinal extremi-
ties rounded ; lateral margins gently curved ; basal margin somewhat more
arcuate in some specimens, while in others the curvature is less. The central
part of the base is, in some shells, slightly extended, while in others this fea-
ture does not exist. Ventral valve depressed convex, gently and regularly
curving from beak to base ; lateral margins slightly elevated over adjacent
portion of valve ; beak moderate and incurved over umbo of opposite valve.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 89

Mesial depression broad but very shallow, and not extending back beyond the
basal third of the valve : in some instances no depression is observable. Dor-
sal valve more or less convex, according to age; in young shells nearly flat, in
old ones, on the contrary, even gibbous. Mesial fold only faintly indicated in
very old specimens; in all others not the slightest trace of it is visible. Surface
marked by strong angular plications, which increase towards the margins by
bifurcation, and by lamellose, imbricating concentric striae, which give the
shell a rugose appearance.

This species is easily distinguished from its congener, Atrypa reticularis, by
its stronger radii, and by its rugose surface ; also by its smaller size ; its largest
specimens seldom exceed in length and width one-half of cardinal dimensions
of the larger A. reticularis.

Formation and Locality. — Found in the upper strata of the Devonian limestone, in Jefferson county,
Ky., and in Clark county, Indiana. The steep banks on the Indiana side of the Ohio river, opposite the
Falls, have furnished a considerable number of very fine specimens of this species. It is a peculiar ap-
pearance, that in the rotten hornstone of those banks, the ventral valves of this species occur very abund-
antly, weathered out and silicified, while very seldom a single dorsal valve. is found. I have, for instance,
collected there more than twenty-five single ventral valves, but did not find a single dorsal one. In some
of the specimens there found, both valves are perfect and at the same time separate, showing exquisitely
the interior arrangement of the shell.

Atrypa calvini. x. SP.

Plate XXXII., figures 64, 65 and 66.

Shell below medium size ; sub-circular or sub-elliptical ; moderately convex ;
hinge-line less than greatest width of shell ; cardinal extremities rounded or
forming a very obtuse angle ; width greater than length. Surface plicated.

Ventral valve depressed convex ; greatest convexity below the umbo, from
where it slopes very gently toward the cardino-lateral margins ; both margins
of the valve, from the cardinal extremities down to the front of the mesial
extension, are abruptly and prominently turned downward, forming a flange
of considerable size in proportion to the shell, and establishing on the valve
two lateral depressions, which are separated from the sinus by its elevated mar-
gins ; the sinus begins at the beak, is well defined, curves regularly and gently
towards the front, where it deflects abruptly upward, and forms a large quad-
rilateral extension, which fits in a corresponding indentation in the base of the
dorsal valve ; beak prominent and elevated above the beak of the other valve;
only slightly arched, and having a small, round perforation in the apex. Dor-
sal valve more convex, almost gibbous ; greatest convexity at the middle of the
valve, from where it slopes abruptly to the lateral basal margins ; the mesial
fold is well defined from beak to base, becoming prominent at the front ; beak
very small and incurved into the fissure of the opposite valve ; umbo almost
Depressed.

OKOL. SUR. — 12

90 PALAEONTOLOGY OF KENTUCKY.

Surface is marked by strong, rounded plications. The sinus is bounded by
a strong rib on each side ; this rib bifurcates below the umbo, and the branch
next to the sinus drops into it, and at the front coalesces with the elevated
flange of its extension ; another rib starts in the bottom of the sinus in front of
the umbo, and extends to the termination of the sinus, having sometimes
bifurcated at about the middle of its length. The mesial fold has generally
two plications on its summit and one on each of its lateral slopes, but the top
ribs are often increased by bifurcation before they reach the front. On each
side of the mesial fold and sinus there are about five or* six plications, of
which only two reach the apex; the others were added, partly by bifurcation,
partly by interpolation. Other surf ace- markings are not visible.

Formation and Locality. — Found in the Niagara group in the quarries east of the city of Louis-
ville, Ky. Although rare, some very fine specimens may be seen in some of the Louisville collections.
This species has in its general outline some resemblance to Khynchonella whitii, of the Niagara rocks from
Waldron, Indiana, but it differs from it by its peculiar plications, and by the marginal flange of its ventral
valve, which two features are sufficient to distinguish it at the first glance from that species. A still
greater resemblance has it to Atrypa nodostriata, as figured by Prof. Hall in Pal. of Ohio, Vol. 2, plate 7,
figures 12, 13 and 14, and described in same volume, page 133. Differences between these figures and our
shells exist only in one or two minor points, which are easily accounted for by the fact that the Ohioan illus-
trations were made from an exfoliated cast, while my specimens are perfect shells. In consequence of this
great resemblance, which amounts almost to indentity, I placed my shells, at first, in the species of A.
nodostriata. But when I examined Prof. Hall's original description and figures of that species, in Pal. N.
Y., Vol. 2, page 272, and plate 56, figures 2a-n, I could not identify my specimens by either. It appears to
me that the description and illustrations in the New York Keport are entirely different from those of the
Ohio Keport. By the New York description and figures the species is established. The Ohio shell, which
is only an exfoliated cast, belongs, undoubtedly, to one and the same species with my specimens, but not to
Atrypa nodostriata of the New York Report. For these reasons I have to establish a new species for the
reception of my specimens and the cast figured in the Ohio Report, and I name this species in honor of
Prof. Samuel Calvin, of Iowa City, Iowa, who ranks as scientist with the foremost of this country, and
whose labors in Geology and Palaeontology have greatly contributed to the wonderful progress made by
those sciences in the latter half of the present century.

Atrypa ellipsoida. N. SP.

Of this beautiful shell I have two specimens in my collection, and if I am
not mistaken, I have seen one or two in some other cabinets. It took me some
time before I could come to a conclusion, whether to leave it with Atrypa
reticularis, which it resembles in every feature, except the form, or to place
it into a new species. I have decided to take the latter course, and I hope
future developments in regard to this shell will prove my decision to be cor-
rect. The description of this new species is as follows :

Shell, 'in proportion to the common size of our A. reticularis, rather small ;
longitudinally sub-elliptical, the shell forming almost a regular ellipsoid ;
length about one and one-half its width, while its depth, measured at the

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 91

points of greatest convexity, equals the width ; hinge-line short and sloping
from the beaks with a forward deflection to the cardinal extremities, which are
rounded ; lateral margins slightly curved or almost straight ; basal margin
strongly curved and sometimes even forming a pointed basal extremity. Sur-
face covered with plications.

Ventral valve less convex than the other ; greatest convexity at the umbo,
from which it slopes in a gentle curve to the front, and to the basal half of
the lateral margins, but more rapidly, almost abruptly, to the cardi no-lateral
margins. The umbo is prominent, and the beak somewhat elevated above,
but incurving closely upon the umbo of opposite valve. No hinge-area nor a
perforation in the beak are visible. The dorsal valve is more gibbous, it slopes
in a regular, light curve to the base, but in a considerably stronger curve to the
lateral and cardinal lines ; its umbo is prominent, and its beak is closely in-
curved into the opposite valve. It is only near, almost at the base, where the
dorsal valve shows a faint elevation, indicating a mesial fold, and the ventral
valve a slight impression in place of a mesial sinus. The dimensions of an
average-sized specimen are : length, nine-tenths of an inch ; width and depth,
six-tenths of an inch.

Formation and Locality. — In the Corniferous limestone at the Falls of the Ohio, on the Indiana
shore of the river.

Atrypa reticularis. LINNAEUS.

Plate XIV., figures 12 to 23, and Plate XV., figure 1.
Atrypa reticularis, Linnaeus. Syst. Nat. ed. XII., p. 1132 — 1767.
Atrypa reticularis, Hall. Pal. N. Y., Vol. IV., p. 316—1867.
See list of synonyms in last cited report.

Shell large, sub-circular or ovoid, convex-concave, but mostly plano-convex ;
length and width almost equal, sometimes width a little greater than length;
surface plicated; hinge-line less than width of shell ; cardinal extremities
rounded, lateral margins gently and regularly curved ; basal margin forming a
somewhat stronger curve, which is sometimes interrupted by a small extension
of the mesial sinus, but oftener by a slight inflection, caused also by sinus.
Dorsal valve very ventricose, sometimes gibbous, having greatest convexity
either at the umbo or in front of it, from where it slopes abruptly to the cardi-
nal and lateral margins, but more gently to the front. In some shells there is
a slight elevation in the center line of the valve from beak to base, indicating
a kind of mesial fold, but in most specimens this feature does not exist ; the
umbo is prominent and regularly rounded ; beak strongly incurved into the
fissure of the other valve. Ventral valve depressed convex in the upper part
near the umbo, but becoming concave on the sides and in front of it. A broad

02 PALAEONTOLOGY OF KENTUCKY.

shallow depression on both sides of the umbonal region extends from the car-
dinal line towards the front, where it connects with the mesial sinus ; the sinus
begins at the middle of the valve and forms a slight extension in front.

In a few instances this extension bends abruptly upwards, and fits in a cor-
responding inflection in the dorsal valve ; beak moderate and closely incurved
upon the umbo of the other valve, showing a slight, rounded perforation in
the apex, which leads into the broad triangular fissure ; cardinal area scarcely
visible. Surface ornamented by strong, rounded or sub-angular plications,
which increase towards the margins by bifurcation as well as by interpolation,
and by lamellose, imbricating concentric striae or lines of growth, which often
give the shell a very rugose appearance, as may be seen in figure 1, plate 15.
The size of the specimens in this species differs greatly among the individuals
illustrated; the larger may be considered as of maximum size, while the
smaller are of average size.

Formation and Locality. — This species, together with Spirifera oweni, with which it is associated,
belong to the most common fossils of the Corniferous limestone, at and around the Falls of the Ohio in
Kentucky and Indiana. In the washes of the fields around Charlestown, Indiana, a collector can pick up,
after some hard rains, in a day's hunt, more than a hundred fair specimens of this species ; they are mostly
silicified, and often contain the spiral coils, as may be seen in figures 18, 20, 21 and 22. There is a pretty
little shell in the Niagara rocks, which is placed also in this species, though the difference in the exterior
features of the Devonian and Silurian shells is so conspicuous, that nobody can overlook it. For what
reason these two fossils are kept in the same species I can not understand, and I shall, therefore, separate
the Niagara specimens from the Devonian, at least as a variety.

Atrypa reticularis, var, niagarensis, N. TAB.

Plate XXXII., figures 5 to 8, and 44 to 47.

Shell small, at least below medium size ; longitudinally sub-elliptical or sub-
ovate, plano-convex ; hinge-line less than the width of the shell ; cardinal
extremities rounded ; length somewhat greater than the width ; base regularly
curved, sometimes slightly inflected in the center ; lateral margins gently
curved.

Ventral valve slightly convex in the umbonal region ; all around this and to
the base there exists a slight depression, which forms at the front the mesial
sinus; beak moderate and incurved upon the umbo of the other valve. In
some specimens the sinus is produced beyond the front, and the extension,
thus formed, often rapidly and abruptly bends upward, as may be seen in figure
7, plate 32 ; in others there is scarcely a sinus noticeable. Dorsal valve very
ventricose or gibbous, sloping abruptly from the middle, where the greatest
convexity is, toward the cardinal and lateral margins, but less abruptly towards
the front. No mesial elevation is indicated, except in those specimens where
the frontal extension of the ventral valve makes an abrupt upward turn ; here

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 93

the dorsal valve is also deflected upward at the base and in the basal quarter.
Surface covered by fine thread-like striae, which increase towards the margins
by bifurcation ; there are, also, tine concentric lines of growth.

Formation and Locality. — Found abundantly and as well preserved specimens in the Niagara rocks
in Jefferson county, Ky., and in Clark county, Indiana. It differs from its Devonian cousin by its consid-
erably smaller size, which seldom exceeds that of the specimens illustrated on plate 32, and also by the
finer and elegant ornamentation u[ its suri'uco,

Genus Cyrtia. Daiman.

Cyrtia, Daiman. Kongl. Vet. Acad. Handl.— 1827.
Etymology : Kyrtia, a fishing basket.

This genus includes certain spiriferoid forms, possessing semi- conical or
semi-pyramidal ventral valves, high, flat areas, with a narrow fissure closed by
a convex pseudo-deltidium. Some of the species have a round perforation in
the upper part of the pseudo-deltidium ; but this feature is not constant; it
may be present or absent, and has not been considered of generic significance.
The types of Daiman' s genus, Cyrtia, are C. exporrecta and C. trapezoidalis,
which are now considered identical. In 1858, Mr. Davidson separated several
species, which were then classed with Cyrtia, from it, because they did not
correspond with the types in several important points, and placed these in the
genus Cyrtina. Both genera differ in the shell structure, which in Cyrtia is
impunctate, while it is punctate in Cyrtina. The dental plates of the ventral
valve in Cyrtia are similar to those of Spirifera, while those in the ventral
valve of Cyrtiua are greatly different and show a peculiar modification.

Cyrtia exporrecta. WAHLKNBBRQ.

Plate XXVII., figures 6, 7, 8 and 20.

Cyrtia exporrecta, Wahlenberg. Nova. Acta. Regiae. Soc. Sci., Vol. 8, Niagara group — 1821.
Spirifera (Cyrtia) trapezoides. Hall. 24th Rep. N. Y. State Museum, p. 183—1872.
Oyrtia trapezoides, Hall. 27th Rep. N. Y. State Museum, pi. 9, figures 19, 20 and 21—1875.

Shell below medium size, pyramidal when resting on the dorsal valve ; hinge
line longer than the greatest width of the shell, but sometimes a little less.
Cardinal extremities mostly acute, sometimes obtuse, but never rounded. Sur-
face smooth without plications. Ventral valve regularly pyramidal, forming
at the apex an almost right-angle triangle. Mesial sinus extending from apex
to front, where it forms a medium sized quadrilateral extension, well defined,
but shallow and rounded or flattened in the bottom, and rather narrow in
front. Cardinal area greatly elevated, sharply defined in its margins, more or
less concave, being mostly vertical, but sometimes leaning a little either to the

94 PALAEONTOLOGY OF KENTUCKY.

front or rear. Beak arching over a high but very narrow fissure, which is gen-
erally closed, and shows a foramen a little above the middle, as may be seen
in figure 35, plate 34.

Dorsal valve semi-elliptical, depressed ventricose ; greatest convexity about
the middle, from where it slopes with a gentle curve to the front and sides,
but flattened at the cardinal angles ; mesial fold well defined, extending from
beak to front, low and flattened, or even depressed in the middle ; beak in-
curved over a very narrow or linear area.

Surface marked by fine radiating striae, which increase in size and distance
from apex to front ; there is neither bifurcation nor interpolation of striae.

Size of this species is somewhat variable ; a specimen of average size has the
following dimensions : length, six lines ; height, seven lines, and width, nine
lines and one-half. In figure 6, plate 27, the dorsal valve is represented with
rounded cardinal angles, which is a mistake, caused by defects in the specimen
copied. The angles should be obtuse.

Formation and Locality. — Occurs in the upper strata of the Niagara formation, in the quarries east
of the city of Louisville, Ky. It is not very rare, though well preserved specimens are seldom found.

Cyrtia exporrecta, var. arrecta. HALL.

Plate XXVII., figure 21, and plate XXXIV., figure 35; plate XXXII., figures 60 and 61.
Spirifera (Cyrtia) exporrecta, var. arrecta, Hall. 24th Kep. N. Y. State Museum, page 183 — 1872.
Cyrtia trapezoidalis, var. arrecta, Hall. 27th Rep. N. Y. Museum, pi. 9, figures 22 and 23 — 1875.

This shell resembles in most important points the preceding species, from
which it, however, differs in the following features ;

1. The cardinal area of its ventral valve is more elevated, narrower in its
base, and never curved, but always straight, and generally leaning a little
towards the front. In several specimens before me, the cardinal area shows,
even in its upper part, a marked convexity, the beak curving really a little
into the mesial sinus ; but this feature may be the consequence of distortion,
though the shells in question do not show any indications of being subjected
to any compression or other violence.

2. The excess of its height over its length is in these specimens considerably
greater than in the foregoing species.

3. Its mesial sinus appears to be somewhat more angular, and proportionably
deeper than that of Cyrtia exporrecta.

It is obvious that specimens exist which may, with equal right, be placed in
either species, but usually the species are easily separated.

Formation and Locality. — Found associated with the former in the upper strata of the Niagara
formation, in the quarries east of the city of Louisville, Ky. Is rather rare.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 95

Genus Cyrtina. Davidson.

Cyrtina, Davidson. Monog. Brit. Carb. Brachiopoda — 1858.
Etymology: Kyrtia, a fishing basket.

Shell small and resembling that of Spirifera in its general form. Shell struc-
ture punctate. Valves very unequal ; ventral valve elevated and pyramidal
in shape ; area very high, with a long narrow foramen, closed by a pseudo-del-
tidium ; dental lamellae converging from margins of foramen, and uniting to
form a mesial plate or septum, which divides the cavity of the ventral valve
into two compartments. Dorsal valve nearly flat or moderately convex.
Spires well developed, and resembling those of Spirifera and Spiriferina.
The genus Cyrtina is closely allied to Cyrtia, of Dalman, and Spiriferina, of
D'Orbigny, and has, also, near relationship with the genus Spirifera.

Cyrtina crassa. HALL.

Plate XIII., figures 21, 22, 23 and 24.
Cyrtina crassa, Hall. Pal. N. Y., Vol. IV., p. 267, pi. 27—1867

Shell depressed pyramidal, semi- elliptical in a dorsal view ; hinge-line about
equal to greatest width of shell, with the extremities slightly rounded ; surface
plicate ; shell of medium size.

Ventral valve depressed pyramidal, convex regularly arched from beak to
front, and also from sinus to margins of cardinal area ; sinus broad and
rounded in botiom ; beak extended and slightly incurved over area, which has
a height equal to one-half the width of shell, and which is almost straight in
its lower half, and regularly curved in the upper part ; fissure prominent, twice
as high as wide in the base1.

Dorsal valve slightly convex, little curved from front to rear or in lat-
eral direction ; flat or even a little concave at cardinal-extremities ; mesial fold
broad, moderately elevated, rounded on top and strongly defined ; cardinal
area linear.

Surface marked on each side of the mesial fold and sinus by about four
strong, low, rounded plications, which are crossed by fine, thread-like con-
centric striae, and a few imbricating folds. (Hall.) Size of the only specimen
in my possession is as follows : length, nine lines ; width, fourteen and one-
half lines ; and depth, nine lines and one-half.

Formation and Locality. — Occurs in the Corniferous limestone around the Falls of the Ohio, but
is exceedingly rare. So far as I know, only three specimens of this species were ever found ; two of them
belonged to the cabinet of the late Dr. James Knapp, and the third one was found by myself} it is copied
on plate 13,

96 PALAEONTOLOGY OF KENTUCKY.

Cyrtina hamiltoniae. HALL.

Plate XIII., figures 4 to 12.

Cyrtia hamiltonensis, Hall. Tenth Kep. on St. Cab., p. 166—1857.
Cyrtia hamiltonensis, Billings. Dev. Foss. of Can. "West., p. 263 — 1861.
Compare Cyrtia acutirostra, Shumard, Geol. Kep. Missouri, part 1, p. 204 — 1854.
Cyrtina hamiltonensis, Nicholson. Pal. of Ontario, p. 83 — 1874.
Cyrtina hamiltoniae, Hall. 24th Rep. N. Y. St. Mus., p. 198—1872.

Shell small, more or less triangular, sub-pyramidal ; hinge-line equal to
greatest width of shell ; proportions of length, width and depth variable, but
frequently width is equal to length of ventral valve, and height of area is equal
to length of dorsal valve. Surface plicate.

Ventral valve quadrilateral in outline, obliquely sub-pyramidal, most promi-
nent at beak, which is very variable in elevation, and straight or a little arched
over cardinal area, and not unfrequently attenuate and distorted or turned to
one side ; mesial sinus wide and strongly defined, rounded or sub-angular in
bottom ; area variable, large and elevated, plane or arcuate in different degrees,
with its lateral margins angular, distinctly striate in both directions ; fissure
narrow, closed by a convex, pseudo-deltidium, which is perforated above by
an oval foramen. Dorsal valve depressed convex, with a broad, more or less
prominent mesial fold, which is bounded by broader furrows than those be-
tween the plications, and is sometimes extremely elevated in front ; beak
scarcely rising above hinge-line ; area narrow, almost linear, but quite distinct.

Surface marked by about six to eight (rarely one or two more) simple,
rounded plications on each side of mesial fold or sinus, and these are crossed
by very fine concentric lines of growth, which, at intervals, become crowded
and sub -imbricate, especially towards margins of shell. The finer surface-
marking is minutely granulose or papillose and shell structure distinctly punc-
tate. In some of the larger individuals there is an obscure elevation on each
slope of sinus, resembling an obsolete plication. The longitudinal medium
septum extends for more than half the length of the ventral valve, and is con-
tinued into the cavity beneath pseudo-deltidium. These features are shown
in casts and in transverse sections of valve. The dorsal valve shows a double
or bilobed cardinal process with the strong crural bases supporting spiral arms,
which are directed into the two compartments of the ventral valve, and,
making numerous turns, terminate in the rostral part of the shell.

Formation and Locality. — This species is found in the Hamilton group in different localities. At
Widder Station, in Canada West, it occurs in great abundance, and in most perfectly preserved specimens.
In the Corniferous group around the Falls of the Ohio it is also somewhat abundant in good but silici-
fied specimens.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 97

Cyrtina hamiltoniae, var. recta, HALL.

Plate XIII., figures 13 to 16.
Oyriina hamiltonensis, var. recta, Hall. Pal. N. Y., Vol. IV., p. 270—1867.

Prof. Hall separates this shell from the species Hamiltoniae, and makes a
variety of it, which is based upon two points : first, upon the plane, flat area
and straight beak, and second, upon the angular plications. If only the ex-
treme forms were in existence, those points would suffice to maintain the new
variety ; but inasmuch as the species Cyrtina hamiltoniae is very variable in
shape, we find individuals which gradually lead from one form to the other.
Three groups may be distinguished among these shells ; in the first we find
specimens with very arcuate or concave cardinal area, such as shown in figure
11, plate 13 ; in the second group the cardinal area is only slightly curved near
the beak, and the latter is always somewhat; twisted or turned to one side ; and
in the last group we find the forms, separated by Prof. Hall from the main
species, and put in the variety recta. In these shells the cardinal area is
always plane or flat, and leaning generally towards the front, and the beak is
without any curvature. Intermediate forms connect the first with the second
group, and others lead from the second to the third group.

Formation and Locality. — Found associated with the preceding species.

Genus Meristella. Han.

Meristella, Hall. 13th Regent's Report— 1860.
Etymology : a diminutive of Merista.

The shells of this genus are oval, ovoid or sub-orbicular, elongate or rarely
transverse ; valves unequally convex, with or without a median fold or sinus ;
beak of the ventral valve often with a circular foramen and incurved over the
umbo of the dorsal valve. Area none ; valves articulating by teeth and
sockets ; surface smooth or with fine concentric lines of growth, and with
very fine, indistinct or obsolete radiating striae.

The interior of the dorsal valve is marked by the presence of a strong
hinge-plate or cardinal process, and from the base of this proceeds a thin,
longitudinal septum, which often extends for half the length of the valve.
The interior of the ventral valve shows a triangular fissure below the beak,
which joins a semi-circular perforation at the apex. At the base of this fissure
are two strong teeth, which extend in thickened or slender plates to bottom of
cavity, and curve around upper part of the muscular area, which is broadly
triangular or ovate. There is sometimes a thickening of the shell at the base
of the rostral cavity, which abruptly limits the muscular impression ; but there
is neither septum nor rudiment of one as in Merista,

QEOL. SUK.— 13

98 PALEONTOLOGY OP KENTUCKY.

Meristella nasuta. C»NKAD.

Plate XV., figures 2 to 8.

Atrypa nasuta., Conrad. Ann. Kep. on Pal. N". Y., p. 18.
Meristella nasuta, Hall. Thirteenth Rep. on St. Cab., p. 93— 186t.
Meristella elissa, Hall. Fourteenth Rep. on St. Cab., p. 100—1861.
Meristella nasuta, Hall. Fifteenth Rep. on St. Cab., p. 160 — 1862.
Athyris clara, Billings. Canadian Journ., p. 274 — 1860.
Athyris clara, Geology of Canada, p. 373 — 1863.
Meristella nasuta, Hall. Pal. N. Y., Vol. IV., p. 299—1867.

Shell large, sub-oval, ovate or sub-rhomboidal ; the greatest width near or a
little below the middle ; length equalling or slightly exceeding width. Both
valves convex, the ventral one rather gibbous. A nasute or linguiform exten-
sion of tiie front in old shells.

Ventral valve exceeding the other one considerably in convexity ; point of
greatest curvature being a little above the middle, from where it slopes in
strong curves towards the lateral margins and to the cardinal lines, but in
somewhat gentler curves to the front.

Umbo extremely prominent; beak regularly rounded and closely incurved.
The anterior portion of the valve is produced into a nasute or linguiform ex-
tension ; no depression for a mesial sinus is noticeable. In young or half grown
individuals no basal extension exists. Dorsal valve less convex than the oppo-
site, moderately and regularly convex in young shell, becoming in old shells
gibbous above, curving regularly to the sides, and often a little flattened at the
baso-lateral margins ; at about the middle of the length, or sometimes above,
the central portion of the valve becomes more gibbous, and towards the front
is abruptly elevated into a rounded prominent fold, corresponding to the lin-
guiform extension of the opposite valve. The beak is moderately incurved,
lying close beneath that of the opposite valve.

The general aspect of the surface is that of a smooth shell with a few concen-
tric lines of growth ; in perfect individuals, however, the entire surface is
ornamented by very fine concentric lines, and usually by indistinct radiating
striae, which are often more conspicuous in the partially exfoliated shell, and
still more distinct in some of the casts. The interior of the ventral valve pre-
serves the generic characters in a marked degree, in the open fissure beneath
the beak, which is terminated by a sub-circular perforation ; in the strong
dental plates, and deeply marked muscular impression. The inner surface,
surrounding the muscular impression is covered by radiating striae. The
interior of the dorsal valve shows a strong cardinal process, with a shallow,
spoon-shaped depression in center, margined by deep teeth sockets. The mus-
cular area is elongate-ovate, broader above, and divided through the center by
a thin elevated septum.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 99

This shell is described by Mr. Billings, of the Canadian Geological Survey,
under the name of Athyris clara, but, inasmuch as Mr. Conrad's name of
Atrypa nasuta preceded that of Mr. Billings, his species has priority, while
that of Billings must be dropped.

Both in general exterior, form and internal characters, this species bears
much resemblance to Meristella (Atrypa) tumida of Dalman, but in Dalman's
species there is a distinct sinus in the ventral valve, while the umbo is more
gibbous, the beak larger and more incurved, and the entire shell is compara-
tively more ventricose. The muscular area in the ventral valve is of the same
shape, but narrower than the prevailing form in our species.

Formation and Locality. — Found in the upper strata of the Devonian group at and around the
Falls of the Ohio in Kentucky and Indiana. It is of rather rare occurrence, and fair specimens still more
so.

Meristella unisulcata. CONRAD.

Plate XV., figures 9 to 16.

Atrypa unisulcata, Conrad. Ann. Rep. on the Pal. of N. Y., p. 56 — 1841.
Rhynchonella unisulcata (Conrad sp.), Hall. Tenth Rep. St. Cab., p. 125 — 1857.
Atrypa unisulcata, referred with doubt to Meristella, and name Goniocoelia proposed in Fourteenth Rep.

St. Cab., p. 101—1861.

Compare: Pentagonia peersii, Cozzens. Ann. of N. Y. Lye., Vol. III., p. 158 — 1846.
Meristella unisulcata, Hall. Pal. N. Y., Vol. IV., p. 309, pi. L.— 1867.

Shell of medium size, sub-trigonal, quadrilateral or sometimes sub-pentago-
nal in outline; wider in front, with the sides sometimes sloping from the beak,
but in others the hinge-line is extended nearly straight, and the sides rectangu-
lar to it. A wide mesial depression on one side with prominent elevation.

Ventral valve, with a broad, deep mesial sinus, which occupies nearly whole
width of valve, and is bounded on either side by an angular elevation, which
extends from beak to baso-lateral angles. The portion of the valve, outside of
limitation sinus, is abruptly inflected upwards or towards the dorsal valve,
often nearly at right-angles. Umbo is prominent, and beak is incurved over
umbo of dorsal valve.

Dorsal valve gibbous in the middle ; the center occupied by a prominent
mesial fold, from which the surface slopes abruptly to the lateral angles, be-
coming more or less concave within the lateral and cardino-lateral margins.
The mesial fold is marked along the center by a single deep groove, which
extends to the beak of the valve. Surface marked by fine concentric striae,
and sometimes by strong imbricating folds ; there are also slight indications of
interrupted radiating striae. The specimens of our limestone are either exfoli-
ated or silicified; in both cases the finer markings are obliterated. The interior
of the ventral valve, specimens of which are found in an excellent state of pres-

100 PALAEONTOLOGY OF KENTUCKY.

ervation, shows a perforation in the beak, opening below into an angular
space, which has been occupied by the beak of the other valve, and thence
communicating with the main cavity of the valve. The base of the fissure is
margined on each side by a strong tooth, which extends in strong dental plates
to bottom of cavity, and these are often continued in a thickened ridge bor-
dering the muscular impression. The imprints of the adductor muscles are
opposite the base of the dental plates, and below and on either side are the
imprints of the broad divaricator muscle. In dorsal valve, cardinal process is
broad and strong ; crural bases somewhat widely diverging and center abruptly
depressed. The teeth sockets are large, and supported by strong lamellar cal-
losities, which extend along inner side of the valve nearly parallel to the ex-
terior margin. The muscular imprints are divided by a low distinct septum.
This shell presents considerable variation in its form and general aspect,
though always preserving its unmistakable character. In young and half
grown shells, where the hinge-line is but little extended, it has a general tri-
angular form. When the hinge-line becomes extended, and the sides nearly
straight, with a moderately curving base, it is quadrangular. Some specimens
assume the shape of a hexagon, others of a pentagon. In some individuals
there is a slight elevation in center of sinus, but this is of rare occurrence,
oftener the sinus contains a central rounded depression, margined by a slight
elevation, which extends from beak to front. The beak of the ventral valve
is sometimes not closely pressed upon the dorsal umbo, but in most specimens
is such the case, and oftentimes to such a degree that the apex is incurved into
the groove of the mesial fold. On the dorsal valve we find two considerable
elevations, one on each side of the mesial fold ; they start from the cardino-
lateral margins, near to which they have their maximum elevation, gradually
decreasing until they disappear in the surface of the valve a little above its
middle ; their direction is not quite parallel to the mesial groove, but is deflect-
ing outwards. (Copied from Hall's description, with many alterations of my
own.)

Formation and Locality. — Found in the upper strata of the Corniferous group surrounding the
Falls of the Ohio, in Kentucky and Indiana, where fractions of this species are pretty abundant in some
localities, but fine and well preserved specimens of the whole shell, as well as of single valves, which are
found, are exceedingly rare. My cabinet contains some exquisite examples of this species. The fossils ot
the Corniferous strata, from the neighborhood of the Falls, are, on the Indiana side of the river, generally
more numerous, and in the average better preserved, than those found in Kentucky. The little town
Charlestown, in Clarke county, Indiana, two or three miles off the river, is about the center of one of the
richest fields of the Devonian formation, which has furnished a great many cabinets with very choice speci-
mens. A day's rambling in the washes of the fields around Charlestown, after several days' hard rain, is
a real treat to any geologist, and never fails to fill his basket with fine shells, beautiful corals, and some-
times, but not very often, with rare crinoids.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 101

Genus Meristina. Han.

MeriaKna, Hall. 20th Regent's Keport— 1867.

Etymology: Merista, a genus of shells; inus, implying resemblance.

The shells of this genus resemble in shape and general aspect those of Mer-
istella ; they differ only from the latter by internal arrangement of the loops.
The lamellae of the shells of this genus are united by a single loop only. This
interior arrangement is observed in Meristina maria and M. nitida, both of the
Magara group. In neither of these species is there any indication of acces-
sory lamellae, as in Athyris, nor evidence of the extension of the loop beyond
a certain point. The simple character of the spires in these forms are of
sufficient value to constitute a new genus, that of Meristina.

Meristina maria. HALL.

Plate XXIX., figures 7, 8, 9 and 10.

Mcristella maria, Hall. Trans. Alb. Inst., Vol. IV., p. 212—1863.
Meristina maria, Hall. Pal. N. Y., Vol. IV., p. 299—1867.
Meristina maria, Hall. 28th Bep. N. Y. St. Mus., Mus. Edit., p. 159—1879.
Meristina maria, Hall, llth Geol. Kep. of Ind., p. 299—1881.

Shell of large, at least of more than medium size, ventricose, broadly ovate
or subquadrangular ; length and width usually equal ; greatest width at one
third of length from base or front. Ventral valve gibbous in the upper half,
having a slight elevation from beak to middle of valve, where it becomes de-
pressed and sinuate, and abruptly deflected upward into a linguiform basal
extension, from the point of greatest convexity, which is a little above middle
of valve; it slopes gently to lateral and basal margins, but more abruptly to the
cardinal margins, at which the cardinal borders are inflected. Umbo is prom-
inent, and beak strongly incurved upon the umbo of other valve. Dorsal valve
gibbous, greatest convexity below umbo, from where it slopes abruptly to
cardinal margins, but in a gentle curve to the lateral and basal margins ; a sub-
angular ridge extends from beak to front, near which it increases rapidly in
width and elevation, thus forming a prominent but undefined mesial fold ;
umbo moderate, and beak strongly incurved under that of other valve.

Surface marked by strong, concentric lines of growth. Interior of ventral
valve marked by two strong diverging dental lamellae, which extend to near
the middle, limiting a deep, triangular muscular cavity.

This species is most nearly related to Meristella (Merista) tumida of Euro-
pean authors, but is less rotund, while that species does not possess the pecu-
liar flattening of the cardinal half of the ventral valve, and its accompanying

102 PALEONTOLOGY OF KENTUCKY.

subangular ridge. It differs from all other species of the Niagara and Lower
Helderberg groups, but approaches in some characters to Meristella (Atrypa)
crassirostrata of the Niagara group. From Meristina nitida, with which it is
usually associated, it differs greatly, and is therefore easily distinguished.

Formation and Locality. — Found in the Niagara strata in the quarries east of the city of Louis-
ville, Ky., where it is, however, somewhat rare, at least in well preserved specimens, while at Waldron,
Indiana, it occurs in great abundance, and of great beauty and perfection.

Meristina nitida. HALL.

Plate XXXIII.. figures 10 and 11.

Atrypa nitida, Hall. Geol. of N. Y., Geol. Sur. 4th dist., Tab. of Org. Remains, p. 11—1848.
Atrypa nitida, Hall. Pal. N. Y., Vol. II., p. 268, pi. 65—1852.
Merista nitida, Hall. 12th Eep. St. Cab. Nat. Hist., p. 78—1859.
Meristella nitida, Hall. Trans. Alb. Inst., Vol. IV., p. 226—1863.
Meristina nitida. Hall. Pal. N. Y., Vol. IV., p. 299—1867.
Meristina nitida, Hall. 28th Eep. N. Y. St. Mus., Nat. Hist. Edit., p 160—1879.
Meristina nitida, Hall, llth Geol. Eep. of Indiana, p. 300—1881.

Shell, as found in the neighborhood of Louisville, of small size ; those found
at Waldron, Indiana, of medium size, sub-triangular, with a sinuate base and
largely extended beaks ; most of the shell only moderately convex, but some
becoming very gibbous, even, in isolated instances, per-gibbous ; lateral and
basal margins broad and square, owing to the fact that in both valves the mar-
ginal borders inflect almost rectangularly. Only in few individuals do both
valves slope regularly without inflection to their edges, and meet under an
acute angle (see figures 10 and 11, plate 33). Ventral valve usually of equal
convexity with dorsal, showing in its basal third a slight depression, which
terminates in basal inflection or emargination ; the beak is much elevated above
and incurving over beak of the opposite valve

Dorsal valve has no indication of a mesial elevation ; its beak is strongly
incurved into ventral valve. There are no surface-markings except a few con-
centric lines of growth.

Formation and Locality. — It occurs usually associated with Meristina maria in the Niagara strata
east of the city of Louisville, Ky.; it is, however, not as rare as that species, but is found pretty abundantly
and also in very small but well preserved specimens. Shells of this species from Waldron, Indiana, are
often of more than double size of even our largest individuals. This species is easily identified, inasmuch
as it differs considerably from all other species of the Upper Silurian formation. The shells figured are
different from the usual forms.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 103

Genus Nucleospira. Han.

Nucleospira, Hall. Pal. N. Y., Vol. III., page 219—1869.

Etymology: nucleus, a kernel; spira, a spire, alluding to the internal spire of these shells.

Shell spheroidal or transversely elliptical, more or less gibbous or ventricose,
furnished with internal spires, as in Spirifer. Hinge-line shorter than width
of shell ; cardinal extremities rounded. Valves sub-equal, articulating by
teeth and sockets. Ventral beak extended beyond the dorsal, and beneath it
a triangular depression or area, which sometimes terminates in a shallow,
spoon-shaped pit, on each side of which, at the base, is a strong tooth. A
narrow ridge or septum extends along the center of inner side of valve from
beak to base.

Dorsal valve furnished with a strong, spatulate, cardinal process, which,
rising vertically from cardinal margin, is closely grasped at its base by the car-
dinal teeth of other valve, and thence bending abruptly upwards, and expand-
ing, is projected into the cavity of other beak, lying close upon under side of
false area. This process is grooved or depressed in the center of the upper
side, so as to leave between it and the arch of the ventral beak a narrow space
for the passage of a pedicle, for protrusion of which a minute foramen is
sometimes observed in beak. From the sides of this process, above the junc-
tion of teeth of other valve, and at the point where it bends upward, originate
the brachial processes, which support the spires. A deep cavity beneath the
cardinal process extends to dorsal beak, from which originates a thin elevated
septum, running to base of shell. Muscular imprints confined to a narrow,
oval space. Surface smooth ; shell structure punctate, and, when perfect,
covered with minute hair- like spines.

Nucleospira concinna. HALL.

Plate XXXII., figures 1, 2, 3 and 4.

Atrypa concinna, Hall. Geol. Rep/4th Dist. of N. Y., p. 200—1843.
Nucleospira concinna, Hall. Twelfth Rep. on St. Cab., p. 25 — 1859.
Nucleospira concinna, Hall. Pal. N. Y., Vol. IV., p. 279—1867.

Shell small, depressed, sub-spheroidal, nearly circular in outline ; width
being usually a little greater than length ; valves sub-equal. Ventral valve
regularly convex, greatest convexity a little above middle, and curving regu-
larly to the sides and front ; umbo prominent ; beak neatly pointed and in-
curved over apex of dorsal valve, leaving a space between which sometimes
exposes the narrow area. There is usually a narrow depressed line from beak
to base of valve ; but this is often absent, or so faint as not to be readily ob-
served. Dorsal valve regularly convex, sometimes gibbous, becoming a little

104 PALAEONTOLOGY OF KENTUCKY.

depressed towards base ; the greatest convexity a little above middle of valve.
The hinge-line is about one-third and sometimes one-half as long as width of
shell. Surface usually smooth or very finely papillose ; but in perfect speci-
mens the surface is covered by numerous fine setae, which are matted together,
and the interstices being filled with clay, it has a rough appearance while
under a lens; these setae give a finely striate aspect. Beneath the fine papillose
surface the texture of the shell is minutely punctate.

Formation and Locality. — Found occasionally in the Corniferous limestone at and around the Falls
of the Ohio, in Kentucky and Indiana. It is a rather rare shell.

Nucleospira elegans. HALL.

Nucleospira elegans, Hall. Pal. N. Y., Vol. III., p. 222—1859.

Shell sub-orbicular, wider than long. Lateral margins strongly curved, baso-
lateral margins very slightly curved, almost straight. Central third of the
base somewhat prolonged or produced, and straight. Ventral valve moderately
convex, except in the umbonal region, which is somewhat gibbous. There is
sometimes, on the elevated center, a flattened or faintly depressed mesial line
from umbo to base ; beak elevated above that of the opposite valve and closely
incurved upon it. Area usually covered by the incurved beak, but sometimes
visible. Dorsal valve depressed convex, but sometimes almost as convex as the
ventral ; more elevated in the umbonal region ; beak small, strongly incurved
beneath the beak of the opposite valve. Surface of the shell finely and beau-
tifully punctate, and sometimes preserving remains of its former pilose cover-
ing. Some specimens of this species, showing the cardinal area, might be
mistaken for Orthis.

Formation and Locality. — Occurs in the Niagara limestone east of the city of Louisville. A large
specimen measures eight lines in width by seven in length, while a smaller one has a width of six lines by
a length of five.

Nucleospira pisiformis. HALL.

Plate XXXIII., figures 7, 8 and 9.
Orthis pisum, Hall. Pal. N. Y., Vol. II., p. 250—1852.
Nucleospira pisiformis, Hall. Pal. N. Y., Vol. III. — 1859.
Nucleospira pisiformis, Hall. Trans. Alb. Inst., Vol. IV., p. 226 — 1863.
Nucleospira pisiformis, Hall. 28th Regent's Rep., p. 160 — 1879.
Nucleospira pisiformis, Hall, llth Geol. Rep. of Ind., p. 302 — 1881.

Shell small, sub-globose ; valve nearly equal, each valve with as light de-
pression down the center. Ventral valve somewhat more convex, and beak
more elevated than in the dorsal. Area narrow, small, scarcely extending

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 105

beyond width of beaks at their base. Surface marked by fine concentric striae,
usually obscured by the covering of minute, hair-like spines, which, when
removed, leave a punctate surface.

Formation and Locality. — Occurs abundantly at Waldron, Indiana, and rarely in the quarries
east of Louisville ; in the Niagara limestone of both places.

Genus Spirifera.

^~ Spirifera, Sowerby. Min. Couch., Vol. II. — 1815.
Etymology: spira, a spire; fera, to bear.

Shell structure fibrous and impunctate ; form very variable, but typical;
more or less three-sided or quadrate, sometimes oval or sub-circular. Hinge-
line straight, mostly as long as, or longer than greatest width of shell,
sometimes shorter. The cardinal angles sometimes obtusely rounded, more
commonly produced and extended, sometimes greatly so. Surface usually
with radiating ribs, or smooth or striated. Generally an elevated fold in one
valve, and a corresponding sinus in the other. Valves articulated by teeth
and sockets. Ventral valve the larger, with a more or less prominent beak, a
well marked area and a triangular foramen, which is sometimes closed by
a pseudo-deltidium. Dorsal valve with a narrow area, and a wide triangular
foramen. Interior more or less occupied by two spirally rolled lamellae, form-
ing two cones, the apices of which are directed towards the cardinal angles.

Spirifera acuminata. CONRAD.

Plate VIII., figures 1 to 8.

Delthyris acuminata, Conrad. Ann. Rep. of Pal. of N. Y., p. 65 — 1839.
Spirifera acuminata, Conrad. Hall in 10th Rep. on State Cab., p. 135 — 1857.
Spirifera acuminata, Hall. Pal. N. Y., Vol. IV., p. 198, plate 29.

Shell large, ventricose, transverse, with the hinge-line usually less than width
of shell ; cardinal extremities rounded or truncate, having a sub-elliptical or
sub-quadrate outline ; mesial fold and sinus extreme. Surface plicated. Ven-
tral valve variably convex on two sides, with a wide mesial sinus, which is well
defined in the upper part, becomes wider and deeper and less distinctly de-
fined in middle of shell, and is produced in front into a long triangular exten-
sion, curving abruptly from the greatest convexity to sides and cardinal
angles ; umbo prominent, with the apex incurved over the wide triangular fis-
sure ; area extending to cardinal angles, with margin rounded except towards
the extremities.

Dorsal valve gibbous, highly elevated in middle into a strong angular mesial
fold, and curving from sides of fold to margin of shell, except at the cardinal

UEOL. SUK. — 14

106 PALAEONTOLOGY OF KENTUCKY.

angles, where it is a little flattened and projecting, so as to give a minute artic-
ulate appearance ; summit of mesial fold regularly arcuate from beak to base :
apex lightly incurved over the narrow, nearly vertical area.

Surface on either side of the fold or sinus marked by from sixteen to twenty
plications, about four or five of which, nearest to the center, are dichotomous
from below the middle of their length ; plications low and rounded above and
flattened below middle, those towards the margin very slender ; first ten or
twelve ribs on each side of the fold or sinus occupy greater part of shell. The
entire surface is marked by delicate concentric striae, which are often crowded
into imbricating lamellose lines towards front of shell. In very perfect speci-
mens these concentric striae are papillose or fimbriated by fine radiating striae.
These fine surface-markings, however, are usually nearly or quite obliter-
ated.

The interior of ventral valve shows but a partial thickening of the shell in
rostral cavity ; teeth are strong and short, dental plates spreading and margin-
ing the upper part of the ovate muscular area, which is broader above, and
sometimes very much resembles this feature in S. striatus.

The casts preserve strong and prominent marks of the muscular impressions,
and sometimes vascular markings outside of the muscular area, while in other
individuals the papillose ovarian markings are very distinctly preserved. In
the cast of the dorsal valve there are sometimes strong impressions of the oc-
clusor muscular markings, and the apex also show the striae of the cardinal
muscular attachment. (Hall.)

This species has some similarity with Spir. macrothyris, but is easily dis-
tinguished from this and all the other Spirifera of our strata by its extremely
elevated angular mesial fold and deep sinus, which are bounded by the dichoto-
mous plications. The size of this species is very variable; it measures from one
inch to two and a quarter inch in width, and from three-fourths of an inch to
an inch and seven-eighths in length.

Spir. acuminata is considered by the European geologists, Dr. F. Roemer
and M. de Verneuil, as identical with the Spirifera cultrijugata of Europe ;
but Mr. Davidson, the eminent English Palaeontologist, has pointed out the
fact that the American species has bifurcating plications, which are not seen
in Roemer' s figures of the European species, and also that the European shell
has less plications than the American. Here again the figures are used to de-
termine the similarity and dissimilarity of two shells. The figures may not
be correct, or it is also possible that the specimen from which Mr. Roemer drew
his picture, like many of our species, did not show dichotomous ribs. Even
Mr. Conrad, who first described Spir. acuminata, did not mention the bifurcated
plications, showing that either his specimens did not possess them at all, or
only in such a faint condition that Mr. Conrad did not notice them. Mr.

FOSSILS OF THE SILUEIAN AND DEVONIAN ROCKS.

Roemer's species is very rare in Germany, making it difficult to procure speci-
mens showing the exact features of perfect shells. From these facts we must
draw the conclusion that both species are either identical, or that one is only
a variety of the other. In this case Mr. Conrad's species has the priority over
Roemer's and Spir. acuminata would be maintained, even if its similarity with
Sp. cultrijugatax were admitted. Figures 7 and 8, plate 8, show a very fine
internal cast of this species.

Formation and Locality. — Pound abundantly and in good condition in the Devonian limestone of
Kentucky and Indiana, around the Falls of the Ohio.

Spirifera atwaterana. s. A. MILLER.

Plate IX., figures 1 to 7.
Spirifer pennatus and Spirifer ligus. Owen. Geol. Kep. of Wisconsin, Iowa and Minnesota, p. 585, pi.

III., figs. 3, 4 and 8—1852.

Spirifer pennatus, Hall. Geology of Iowa, Vol. I., Part II., p. 510, pi. 5 — 1858.
Spirifer ativaterana, S. A. Miller. Proc. Davenport Acad. Sci. — 1878.

This species is generally known under the name of Spir. pennata ; but this
specific designation was used already in 1820 by Atwater for another Spirifera,
and, therefore, another name had to be adopted for this shell. S. A. Miller,
Esq., of Cincinnati, Ohio, named it atwaterana.

This species belongs to the large sized Spirifera ; in width it is not exceeded
by any other kind ; it is very variable in form, from sub-globose to transverse
and broadly triangular semi-circular, or semi-elliptical, sometimes inequi-
lateral ; hinge-line always more or less extended into wing-like expansions,
resembling in this feature Spir. mucronata ; valves mostly equally convex.

Ventral valve most convex in the middle and on the umbo ; beak much
elevated above the hinge-line, more or less pointed and slightly incurved.
Mesial sinus [strongly defined at margins, rapidly widening towards base, and
produced in an angular extension in front. Area large and extending to cardi-
nal extremities^; concave and striated vertically and longitudinally ; foramen
large and open to apex, and forming an equilateral triangle.

Dorsal valve also most gibbous in the middle and on the umbo ; beak mark-
edly incurved ; valve curves from the point of the greatest convexity regularly
to anterior and lateral margins, and is more or less compressed at cardinal
angles ; mesial fold is strongly elevated, sometimes a little flattened on top,
and often sub angular towards front.

Surface marked by from fifteen to twenty-five, or even more simple, rounded
plications on each side of mesial fold and sinus ; central ribs are much stronger
than lateral ones ; of the former only about six to eight on each side reach
apex, all others run out on the margins of the cardinal area. In well preserved

108 PALAEONTOLOGY OF KENTUCKY.

specimens the entire surface is ornamented by slender radiating, striae, which,
however, are not visible in most specimens. Concentric lamellose, imbricating
lines of growth are numerous in some specimens, while others show very few
or even none at all.

Formation and Locality. — Found rarely, and seldom well preserved, in the upper strata of the
Devonian limestone around the Falls of the Ohio, in Kentucky and Indiana.

Spirifera arctisegmenta. HALL.

Plate XII., figures 14 and 15.

Spirifer arctisegmentus, Hall. Tenth Rep. on State Cab. — 1867.
Spirifer arctisegmenta, Hall. Descript. of Hew Pal. Fossils, p. 91 — 1857.
Spirifer arctisegmenta, Hall. Pal. N. Y., Vol. IV., p. 208, pi. 81.

Shell transversety semi-oval ; length equal or less than one-third of width ;
hinge-line equal to greatest width of shell, and terminating in salient angles
or mucronating points. Ventral valve the more convex; most convex at the
umbo, from which it slopes regularly to anterior and lateral margins ; mesial
sinus angular and distinctly defined quite to apex of shell ; beak not incurved ;
area flat and straight and a little inclined towards the front. The lateral view
given of this shell in figure 15, plate 12, is incorrect, by showing the area con-
cave and inclined towards the rear. Fissure narrow and open to apex.

Dorsal valve depressed convex, scarcely flattened towards the cardinal ex-
tremities ; beak and central portion of the shell, together with the linear area,
slightly incurved.

The surface is marked by from five to eight or nine angular plications on
each side of the fold or sinus, which on the ventral valve are slightly curved
towards the front, and of which only about three reach the beak, while the
balance run out along the margins of the cardinal area, where they coalesce
with an elevated ridge, which borders the area. The plications on the dorsal
valve are pretty direct ; fine, close, concentric, undulating striae mark the
entire surface.

This shell may be distinguished from Sp. segmenta, as well as from other
allied forms, by its larger and more angular, as well as less numerous pli-
cations, and in having a distinct linear ridge along margin of area of ventral
valve ; its foramen is likewise narrower, and its sinus deeper and more angular
than in Spir. segmenta. (Hall.)

Formation and Locality — Found in the Corniferous limestone at and around the Falls of the Ohio
in Kentucky and Indiana, where it is, however, of rare occurrence, especially in well preserved speci-

mens.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 109

Spirifera byrnesi. *. SP.

Plate X., figures 1-5, 31-34 and 36-39.

Shell sub quadrate, semi-circular and gibbous in outline; hinge-line equalling
greatest width of shell and terminating in salient angles. Surface plicate.

Ventral valve ventricose and only little more gibbous than other valve; regu-
larly arcuate from beak to front ; greatest convexity in the upper part a little
above the middle, from where it curves regularly to the front and sides ; beak
much elevated above hinge-line, and slightly arcuate. Cardinal area high,
concave, and extending to cardinal angles, where it never forms an acute angle,
but shows always a height of from one-quarter to one- half of a line, a feature
which is not sufficiently expressed in the figures on plate 10 ; mesial sinus
sharply defined, forming a deep triangular groove, with an acute angle at the
bottom, much produced in front ; fissure of medium size.

Dorsal valve gibbous, with a greatly elevated mesial fold, which is edged in
its upper part and rounded below ; beak little elevated and slightly inclined
over a narrow hinge-area. Surface marked by from eight to ten very prominent
and angular plications on each side of the mesial fold and sinus, which are
crossed by strong imbricating concentric lines of growth, showing more promi-
nently in front than in upper portion of shell. Of the plications, the lateral
ones do not reach to the beak, but run out on the margins of the cardinal
area.

The dimensions of this species are as follows : it measures from one-half to
three-fourths of an inch in length, and from three-fourths to seven-eighths of
an inch in width ; its width always exceeds its length.

This species takes an intermediate position between Spir. gregaria and Spir.
varicosa ; it is more transverse than the former, and less so than the latter ; its
umbo is less elevated and curved than that of gregaria, and more so than that
of varicosa ; its deeper and sharply angular sinus, and its more elevated fold,
distinguish it from both of its relations. It is a well marked and easily
recognized species.

Formation and Locality. — Found in the upper strata of the Devonian limestone around the Falls
of the Ohio, in Kentucky and Indiana. Very fine specimens I found in considerable numbers in the
quarries at Lexington, Indiana. I dedicate this species to Dr. K. M. Byrnes, of Cincinnati, Ohio, who
devotes all his spare time to the study of geology and palaeontology, and who greatly contributed to our
knowledge of the Cincinnati fossil fauna.

110 PALEONTOLOGY OF KENTUCKY.

Spirifera conradana. s. A.

Plate VII., figures 11, 12 and 13.

Delthyris fimbriata, Conrad. Jour. Acad. Nat. Science, Philadelphia, Vol. VIII., p. 263—1842.
Spirifera fimbriata, Conrad. Billings in Canadian Jour., p. 259 — 1861.
Spirifera fimbriata, Hall. Pal. N. Y., Vol. IV., p. 214, pi. 33.

Shell transversely sub-elliptical, gibbous; hinge-line less than width of
shell ; cardinal extremities rounded.

Ventral valve gibbous in upper half, regularly curving to front and sides ;
sinus well denned, usually shallow^ and rounded, sometimes deep and angular,
and much produced in front. Beak small and incurved over the area, which
is high and concave, and extending about half the entire width of the shell ;
foramen often limited by a sharp elevated border, which appears to be a pro-
jection of the dental plates.

Dorsal valve gibbous, regularly convex on the sides, a little flattened at the
cardinal extremities ; mesial fold abruptly elevated in the lower part, often but
little elevated or scarcely denned in the upper part ; beak small, slightly
arched over the sub-linear area, which is somewhat concave.

Surface marked by from three to nine low, rounded, often obscure plications
on each side of the mesial fold and sinus ; these are crossed by imbricating,
lamellose striae, which are sometimes wide or distant, and often crowded.
The concentric striae are studded with elongated nodes or tubercles, which are
thus arranged in parallel bands, more or less contiguous, according to distance
of the concentric striae.

The elongate tubercles may, perhaps, more properly be regarded as inter-
rupted radiating striae, which, in the perfect condition of the shell, have,
doubtless, extended in slender spines or setae ; they are termed by Mr. Conrad
short longitudinal striae.

The cardinal area is strongly striated vertically. This species begins its
existence, so far as we know, in the Oriskany sandstone, where it has been so
rarely observed. It occurs in the Schoharie grit, and reaches its greatest
dimensions in the Corniferous limestone, where it not seldom attains a width
of nearly two inches by a length of an inch and a quarter. It is often found
well preserved in the Hamilton formation, but does not here attain the size
it has in the Corniferous limestone. (Hall.)

The Sp. conradana is not found in strata younger than the Hamilton, but
it is represented in later periods by forms showing great similarity to it.

Formation and Locality. — Under this heading I give only the places and groups in which the
species in question is found in Kentucky. Sp. conradana is found in the Devonian limestone of Kentucky
and Indiana, near and at the Falls of the Ohio, but is not abundant This species has been known
ever since Mr. Conrad's first description of the same as Spir. fimbriata, but it can not retain its specific
designation, inasmuch as Mr. Morton pro-occupied the name Spir. fimbriata, in 1836, for a different Spiri-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. Ill

fer of the Coal Measures. Conrad's first description of this species and its naming date only back to 1842.
Mr. Morton's right to the name can not be disputed; Mr. Conrad's species must, therefore, be dropped.
Mr. Miller has proposed the name " Conradana " as a substitute, which I hereby cheerfully accept. Mr.
Miller named the species in honor of Mr. Conrad, former geologist of the State of New York.

Spirifera crispa, var. simplex. HALL.

Plate XVII., figures 36 and 37.
Spirifera crispa, var. simplex, Hall, llth Eep. of Ind. — 1881.

Shell small, semi-circular or semi-elliptical, more or less gibbous or ventri-
cose; both valves about equally convex ; hinge-line somewhat less than the
greatest width of the shell ; cardinal extremities obtuse or rounded. Surface
plicate.

Central valve ventricose, with its greatest convexity about the middle of
the valve, from where it curves regularly towards the anterior and lateral
margins ; mesial sinus well defined from apex to front, deep and angular in
the bottom, and widening towards the front, where it forms a strong triangular
projection ; cardinal area high, but not defined in its margins, which are
rounded, and gradually extend into the surface of the valve ; foramen or fis-
sure long and narrow ; beak arched, but not incurved.

Dorsal valve nearly as ventricose as the other, having its greatest convexity
about the middle of the valve, from where it curves regularly towards front
and sides. Mesial fold well defined, strong and angular ; beak small and curv-
ing over a linear area.

Surface marked on each side of mesial depression and elevation by two or
three plications, of which only the first one near fold or sinus is mostly strong
and well marked, while the others are either only slightly elevated or some-
times entirely obsolete. The whole surface of the shell is covered by strong,
thread-like concentric striae.

These specimens are considerably smaller than those used by Professor Hall
for his figures and description in the Indiana Report, which came from Wal-
dron, Indiana. Even some slight differences exist between our Kentucky
shells and those from Indiana, but these differences do not justify a further
specific separation.

Formation and. Locality. — Occurs in the upper strata of the Niagara formation, in the quarries
east of the city of Louisville, Ky., where it is somewhat abundant, but well preserved specimens are rather
rare.

112 PALEONTOLOGY OF KENTUCKY.

Spirifera davisi. N. sr.

Plate XII., figures 1, 2, 3 and 4.

This shell was given to me by one of the collectors around the Falls of the
Ohio as a Spirifera raricosta, with which it has some similarity, but from which
it is easily distinguished by its form and surface-markings.

The shell is semi-circular or sub-quadrate and gibbous. Hinge-line equal or
larger than the greatest width of the shell. Cardinal extremities acute and
mostly somewhat acuminate. Surface strongly plicated.

Ventral valve considerably more gibbous than dorsal valve, regularly arcuate
from beak to front ; greatest convexity at or a little above middle, and curving
gently to the sides and front, except at the cardinal angles, which are some-
what flattened ; beak much elevated above that of the opposite valve, and
arching over that fissure, but scarcely incurved. Cardinal area high and con-
cave, and reaching to the cardinal extremities. Mesial sinus is broad and
rounded and reaches quite to the apex. Dorsal valve gibbous, most convex in
the middle, flattened or a little concave towards the cardinal extremities. The
mesial fold is very prominent, rounded, and regularly arcuate ; it has a faint
impression extending from beak to middle of valve.

The beak is small and arched over the linear area. Surface is marked by six
to eight rounded or sub-angular plications on each side of the mesial fold and
sinus. The shell is smooth, with the exception of front part, which is marked
by from live to seven strong concentric imbricating lines of growth, which
reach to the cardinal angles, and which give to the shell its peculiar beautiful
front view. Such imbricated front is only noticed in Spir. gregaria and in
Spir. mucronata, in both of which it is less regular and less prominent. Inte-
rior of shell is unknown. The specimens so far found show a great similarity
in form and also in size ; they measure from one inch to one inch and a quarter
in width, by from three-fourths to seven- eighths of an inch in length. This
species is related to Spir. raricosta and to Spir. gregaria. From the former it
differs in its greater number of plications; its somewhat acuminate cardinal
extremities ; its larger and more elevated hinge-area, and by its peculiar
imbricated front. From Spir. gregaria it is distinguished by its larger size,
by its smooth shell, by its greater width, and by its less prominent umbo,
and also by its more marked imbricated front.

Formation and Locality. — Spirifera davisi is found associated with Spir. gregaria in the upper
strata of the Devonian limestone in Kentucky and Indiana, in the neighborhood of the Falls of the Ohio;
it is not abundant, and only found in a few limited localities, where it occurs in well preserved specimens
I have named this species in honor of my friend and co-laborer, W. I. Davis, the author of " Kentucky
Fossil Corals," who devoted his attention and study mostly to the fossil corals, in which the Falls of the
Ohio and its surrounding quarries are so exceedingly rich.

FOSSILS OF THE SILUEIAN AND DEVONIAN BOOKS. 113

Spirifera divaricata. HALL.

Plate XI., figures 6 to 11, and Plate XII., figures 5 to 11.'
Spirifer divaricatus, Hall. Tenth Rep. on the State Cab., p. 130 — 1857.
Spirifer venstus, Hall. Thirteenth Rep. on State Cabinet, p. 82 — 1860.
Spirifera divaricata, Hall. Pal. N. Y., Vol. IV., p. 213, plate 32.

Shell ventricose, somewhat rhomboidal or quadrilateral (looking upon the
ventral valve). Dorsal valve semi-elliptical ; hinge-line less than width of the
shell ; cardinal extremities obtuse or rounded ; area large.

Ventral valve most convex above the middle, extremely arcuate from umbo
to base ; abruptly curving to the sides ; beak abruptly arching over the area ;
sinus plicated, shallow above and becoming rapidly expanded below, with the
margin undefined and terminating in a broad, triangular extension in front.
Area high, flat below, but abruptly arcuate above, and reaching to the cardinal
extremities ; foramen large.

Dorsal valve regularly and strongly convex, with an angular mesial fold,
which is narrow above and expands towards the front, with bifurcating plica-
tions ; sides regularly curving and sometimes a little flattened towards the
cardinal extremities. Area rather wide, with the beak and central portion of
the valve arching over it. The surface is marked by numerous fine bifurcating
rounded or sub-angular plications ; mesial sinus having on each side a stronger
plication, which bifurcates on one or both sides. At the beak there is a single
plication in the bottom of the sinus, which sometimes continues simple nearly
or quite to the base ; while the accessions take place mainly from those on the
sides of the depression, till they reach the number of ten, eleven or twelve
within the limits of the sinus near the base. In a specimen of ordinary size,
where the surface is well preserved, there are, sometimes, sixty and more plica-
tions with their divisions at the margin of the shell. In some specimens from
the Corniferous limestone, where the surface is partially or entirely exfoliated,
the bifurcating character of the striae is not observed, and in some specimens
the plications appear to have been simple throughout. The plications are
crossed by fine imbricating lamellose striae, which are abruptly arched back-
wards. (Plate 12, figure 11.) A cast of the ventral valve shows a large oval
muscular area, which is deeply divided by a rounded median crest, and
strongly striated on the lateral portion. (Hall.)

The shells represented on plate 12, figures 5 to 11, I was, at first, inclined to
consider as specifically different from Sp. divaricata. They appeared more
robust, and their plications were fewer and stronger. Instead of a simple
bifurcation, as in divaricata, these specimens show some instances where a
single plication divided towards the base into three and even four branches,
forming a kind of fascicle, which are so characteristic in Spirifera camerata of

GKOL. SUR. — 15

114 PALAEONTOLOGY OF KENTUCKY.

the Coal Measures. The true character of the plications of these shells is not
shown exactly in the drawings.

This shell, when well preserved, is one of the finest Spirifera of our palaeo-
zoic fauna ; it is easily distinguished from the others by its form, by its bifur-
cating plications, and by its sharp zigzag, concentric striae.

Its size differs from two to three inches in width, and from one and three-
fourths to two inches in length, by a depth of one inch and one-eighth.

Formation and Locality. — Found in the Hamilton group and in the Corniferous limestone of Ken-
tucky, around Louisville, and near Lebanon, Kentucky, where W. T. Knott, Esq., found some very fine
specimens, which are figured on plate 11. This species is not very rare, though it is very difficult to pro-
cure good specimens.

Spirifera duodenaria. HALL.

Plate XII., figures 12, 13 and 16. -

Delthyris duodenaria, Hall. Geol. Rep. 4th Dist. N. Y., p. 171, figure 5 — 1843.
Spirifer duodenaria, Hall. Catalogue in Rep. on State Cabinet.
Spirifera duodenaria, Hall. Pal. N. Y., Vol. IV., p. 189, pi. 27 and 28.

Shell transverse, semi-circular ; hinge-line equal to greatest width of shell ;
cardinal extremities obtuse or acute, rarely acuminate ; valves sub-equally con-
vex ; area very narrow. . Surface plicated.

Ventral valve moderately gibbous ; arcuate, compressed towards the cardinal
extremities. Mesial sinus of moderate width and depth ; rounded or slightly
flattened on the bottom; umbo prominent; beak small, neatly curved over a
wide triangular fissure, and reaching to within half a line of the umbo of the
opposite valve ; area concave, sub- linear, a little wider on each side near the
center.

Dorsal valve regularly convex, a little gibbous in the middle and flattened
or sometimes slightly concave at the cardinal extremities. Mesial fold rather
narrow, rounded, prominent and strongly defined, sometimes a little flattened
on the middle. The surface is marked by six and rarely seven strongly
rounded ribs on each side of the mesial fold or sinus. The ribs gradually
decrease in size and prominence from the center ; and the outer ones are often
scarcely elevated in young or medium- sized individuals. The entire surface is
marked by lamellose, concentric striae, giving a papillose or sub-fimbriate
aspect at their junction ; it usually happens, however, that the surface is
smooth from partial exfoliation. (Hall.)

This species has usually a width of one inch to one inch and a quarter, and a
length of one-half to three-fourths of an inch. Younger individuals, such as
are figured on plate 12, are smaller in size, and generally contain less plications.

Formation and Locality. — This species is found in the Corniferous limestone of Kentucky and
Indiana, around the Falls of the Ohio, but is very rare. During ten years of collecting I have found only
two or three specimens, and these not even in very good condition,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 115

Spirifera dubia. N.BP.

Plate XXXIII., figures 23 and 24.

This shell I found in the strippings of a quarry east of the city of Louis-
ville, where the top rocks belong to the Devonian, and the lower strata to the
Silurian ; it is. therefore, impossible to state to which of these formations it
belongs. It further has in form and outline great similarity with Spir. crispa,
var. simplex, from which it, however, differs greatly in other points. Concern-
ing this shell there is, therefore, doubt in regard to its formation, and also
whether or not it should form a new species, and for these reasons I think it
fully deserves its specific name.

Shell small, semi-circular or semi elliptical and ventricose. Convexity of
both valves almost equal ; hinge line less than greatest width of shell ; cardinal
extremities rounded. Surface without plications.

Ventral valve ventricose, having its greatest convexity a little above the
middle of the shell, from where it curves regularly and markedly to the
anterior and lateral margins. Mesial sinus extends from beak to front, shallow
in the upper part, deepening and widening towards the base ; angular in the
bottom, but its margins not at all defined ; in front it forms a pretty strong
triangular extension. Cardinal area elevated, with undefined rounded mar-
gins ; beak arcuate, but. not incurved over a high and narrow fissure.

Dorsal valve almost as convex as the other, having its greatest convexity a
little above the middle, from where it curves regularly towards the front and
sides. Mesial fold not at all noticeable on the umbo ; little elevated and sub-
angular towards the base ; beak incurved over a narrow area.

Surface having not the least trace of plications, but covered by lamellose,
imbricating, concentric striae, similar to those in Spir. var. simplex. Size of
shell is three-eighths of an inch in length, and a little less than one-half of an
inch in width.

Formation and Locality. — The formation from which it comes uncertain as above stated ; found in
a quarry east of the city of Louisville. This one specimen the only one so far known,

Spirifera euruteines. OWEN.

Plate VI., figures 1 to 7; 9, 11 to 17.

Delthyris (Spirifer) euruteines, Owen. Report of Geological Exploration in Iowa, Wisconsin and Illinois.
Spirifer euruteines, Owen. Geol. Surv. of Wise., Iowa and Minn., p. 586, Tab. III., figs. 2 and 2a, and

6, 6a, b.
Spirifera euruteines, Hall. Pal. of N. Y., Vol. IV., page 209, plate 31, figures 14 to 19.

This species was first described and figured by Prof. David Dale Owen, in
his report on the Geological Survey of Wisconsin, Iowa and Minnesota, from
specimens found on Pine creek, Iowa. Owen states that this is the same shell

116 PALEONTOLOGY OF KENTUCKY.

found in great abundance in the hydraulic limestone at the Falls of the Ohio,
near Louisville. The figures given by him in said report can not belong to one
and the same species ; those marked 2 and 2a are by far too large and robust ;
the cardinal view in figure 2 measures, between the cardinal extremities, two
and one-fourth inches, while the breadth of euruteines was given by Owen to be
one and a half inches. The figures 6, 6<z, 6&, must be taken as the correct
representation of Owen's Sp. euruteines.

Prof. Hall described in Pal. N. Y., volume 4, pages 209, 210 and 211, Sp.
euruteines and Sp. euruteines, var. fornacula ; the difference of these consists
only in the greater curvature of the cardinal area in fornacula. Owen's side
view of euruteines shows the cardinal area considerably concave ; the curvature
equal through the whole area from hinge-line to the apex of the beak ; while
Hall's side view of euruteines marks the cardinal area as straight, with the
exception of a little offset near the beak. Among Hall's figures no side view
is given of fornacula ; we are, therefore, left uncertain as to the amount of cur-
vature required to place a euruteines among the var. fornacula. The hinge- area
in this species is exceedingly variable; in some it is straight, and leans forward,
in others it is also straight, but leans backward ; then, again, it leans forward
but is curved a little near the beak, while in others it leans backward and is
bent either only near the beak or throughout its entire height. Spirifera
euruteines is described by Prof. Hall in Pal. N. Y., volume 4, page 209, as
follows :

Shell semi-elliptical ; length and breadth about as six to ten ; hinge-line
equal to greatest width of shell. Surface plicate.

Ventral valve sub -pyramidal, the elevation being nearly equal to half the
width, curving abruptly and equally to the front and lateral margins ; the
distance from the apex to the cardinal extremity, and to the front of the shell,
being about equal. Apex sometimes projecting slightly over the area ; mesial
sinus shallow, well defined, and reaching to the apex ; sometimes a little
flattened in the bottom. Area extremely elevated, nearly flat or slightly
concave above ; fissure large and open to the apex, the length of its sides being
about once and a half the width of its base.

Dorsal valve moderately and evenly convex, with a well defined, low rounded
mesial fold ; beak and margin of the valve in the middle slightly arched ; area
narrow at the sides, but having the width of a line in the middle. Surface
marked by from 16 to 20 plications on each side of the mesial fold or sinus ;
these plications are rounded and well defined ; about eight of them reach the
apex on the ventral valve, and the remainder coalesce with the angular border
of the area. In perfect specimens, the entire surface has been covered by fine
concentric undulating striae, which are crossed by fine radiating striae ; the
remains of these on some of the silicified specimens give a granulose surface.

FOSSILS OF TEtF, SILURIAN AND DEVONIAN ROCKS. 117

The length of a full grown individual is a little more than three-fourths of
an inch, its width about one inch and three- eighths, and its height also about
three-fourths of an inch. (Hall.)

After the foregoing description Prof. Hall makes the following statement :
"I have before me more than a dozen specimens from near the Falls of
the Ohio, or from Charlestown Landing, among which there is very little varia-
tion in the general features."

If those specimens did not show great variations, they must have formed a
picked lot. I have before me more than an hundred shells of this species,
which I could easily divide into at least live different groups. The extreme
form of each group is so pronounced in its features, and so greatly different
from the extreme form of other groups, that they, by themselves, would con-
stitute good species ; but the intermediate forms connect all these groups to
one single species.

Formation and Locality. — Found in great abundance, and well preserved, in the Devonian limestone
in Kentucky and Indiana, near and at the Falls of the Ohio. Some of the specimens have preserved the
internal spiral coils in almost perfect condition, as may be seen by plate 6, figures 21 and 22.

Spirifera euruteines, var. fornacula. HALL.

Plate VI., figures 8, 10, 18, 19 and 20.
Spirifera. euruteines, var. jornacula, Hall. Pal. N. Y., Vol. IV., page 211, pi. 31, figures 11, 12 and 13.

Prof. Hall, in describing this variety, remarks that it possesses the essential
characters of Spir. euruteines, and points out, as the only difference from that
species, that its area is a little more arcuate in the upper part. Those figured
by "me here are of the type which is generally considered as fornacula by all
the geologists living in the cities around the Falls of the Ohio. The strong
curvature of the whole cardinal area is their only marked characteristic.

Formation and | Locality.— Associated with the preceding species in the Devonian limestone in
Kentucky and Indiana, around the Falls of the Ohio.

Spirifera foggi N.BP.

Plate XXXII., figures 28, 29, 30 and 31.

Shell of medium size ; sub-circular sub-oval or sub-elliptical ; very ventn-
cose or gibbous ; hinge-line greatly less than width of shell ; cardinal extremi-
ties rounded. Surface plicated.

Ventral valve ventricose in young specimens, becoming gibbous in old ones ;
greatest convexity a little above the middle of the valve, from where it slopes
in a gentle regular curve to the front, but abruptly to the cardino-lateral mar-
gins ; a mesial sinus extends from beak to front, well defined in its whole

118 PALAEONTOLOGY OP KENTUCKY.

course, moderately widening, but not, or very little, increasing in depth towards
the front ; flat at the bottom, and having only a small basal extension, which
is not deflected ; umbo more or less prominent, according to age, and beak
strongly arched over the umbo of opposite valve ; hinge -area small and unde-
fined in its margins, which are rounded and coalesce with the surface of the
valve ; triangular fissure of moderate size, with its base to its height as two to
three.

Dorsal valve of equal convexity with the ventral, both in young and old
shells : greatest convexity below the umbo, from where it slopes very abruptly
to the cardinal margin, but in a gentle and regular curve to the lateral and
basal margins ; a mesial fold of moderate elevation and moderate width, but
well defined in its whole course, extends from beak to front, with a flat or
broadly rounded summit ; umbo moderate, and beak strongly incurved into
the foramen of the opposite valve. Surface ornamented by five to six broadly
rounded plications on each side of the mesial fold or sinus, of which only
the first one, adjacent to the median elevation or depression, is of moderate
size and plainly marked from beak to front, while the others diminish in size
and distinctness more and more toward the lateral margins. In well preserved
specimens retaining the shell, the surface is covered with fine, thread-like,
radiating striae, which increase greatly towards the front by bifurcation ; these
striae are crossed by fine imbricating lines of growth, which become somewhat
crowded near the front. This species is generally found as exfoliated casts,
which do not show these radiating and concentric lines, or at least indicate
them only very faintly.

Professor Hall has repeatedly, but always with the expression of doubt,
referred this species to Spirifera niagarensis, but it appears to me that it differs
too much from that shell to be associated with it. Spir. niagarensis shows
in all of HalFs figures large cardinal dimensions ; it has a hinge- line as large
as the width of the shell ; it also has a considerable hinge-area, which is well
defined, and its plications are numerous and plainly marked ; all these points
are greatly different in our shell ; its hinge-line is very short, not exceeding
one-half the width of the shell ; the cardinal area is small, and not defined by
sharp, angular, but by broadly rounded margins, and the plications are few,
and only faintly marked. These differences are certainly sufficient to separate
our shell specifically from Spir. niagarensis. Nearer related is this species to
Spirifera radiata, from which it differs only by its small cardinal area, which,
however, occurs in some specimens of that species also, but mainly by its
plicated surface. It certainly occupies an intermediate position between Spir.
niagarensis and Spir. radiata, of which it presents the transition-form in the
process of evolution.

Formation and Locality — Tt occurs in the Niagara group so prominently exposed in the quarries

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 119

east of the city of Louisville, where it is rare, generally, but more so in well preserved individuals; only
a few specimens of this species are to be found in the different cabinets of the Falls Cities. It affords me
great pleasure to name this species in honor of my friend, the noble-hearted and venerable Mr. Fogg, of
Jeffersonville, Indiana.

Spirifera gregaria. CLAPP.

Plate VIII., figures 9 to 13, and Plate X., figures 6 to 10.

Spirifer gregaria, Clapp. MS.

Spirifer gregaria, Hall. Tenth Kep. on the State Cab., p. 127 — 1857.
Spirifer gregaria, Clapp. Billings in Canadian Jour., p. 128 — 1857.
Spirifera gregaria. Hall. Pal. N. Y., Vol. 4, p. 195, plate 28.

Shell ventricose, sub-globose, semi-oval or sub-quadrate in outline ; hinge-
line usually equal, but sometimes less than width of shell ; cardinal extremities
truncate or somewhat rounded. Surface plicated.

Ventral valve very gibbous, and more so than the dorsal valve ; it is regularly
arcuate from beak to front. Its greatest convexity is at or a little above the
middle, from where it curves somewhat abruptly to the sides, but more gently
to the front ; beak much elevated, and apex closely incurved over the
fissure; area high, concave and extending to the cardinal angles, where it is
sometimes more than half a line high, often distinctly striated ; mesial sinus
rounded or sub-angular and much produced in front.

Dorsal valve very convex with a strong mesial fold, either angular or some-
what flattened along the summit, and sometimes marked by an indistinct
groove ; beak often considerably elevated, and slightly inclined over the
hinge area, which is narrow except in the center, where it widens perceptibly
Surface marked by from six to ten strong rounded ribs on each side of the
mesial fold and sinus. The entire surface is covered with undulating con-
centric striae, which, towards the front, become strong zigzag imbricating
lines of growth, resembling somewhat the front ornamentation of Spirifera
davisi.

The interior of the ventral valve presents a well defined, oval, muscular
impression, with a low crest in the center. The dental plates are often much
thickened, filling the entire rostral cavity, and encroaching upon the muscular
area.

The width of this species ranges from one-half to seven-eighths of an inch,
and the length is usually a little less than the width; but there are some speci-
mens in which the length equals or even exceeds a little the width, as may
be seen in the one figured on plate 8. In very gibbous specimens the beak
of the ventral valve is so extremely elevated, that almost one-half of the ven-
tral valve is above the cardinal line. In the majority of specimens there are
six or seven plications on each side of the mesial fold or sinus. The variable

120 PALEONTOLOGY OF KENTUCKY.

gibbosity of the shell gives an apparent variation in the height of the area ;
the beaks of the two valves sometimes approach very close to each other.
(Hall.)

Formation and Locality. — This species is found abundantly in the Corniferous limestone at and
around the Palls of the Ohio in Kentucky and Indiana. It appears here silicified, in well preserved
specimens of the whole shell, as well as of the separated single valves. Specimens still inclosed in the
limestone are of the same material. From observations made by me at the Falls of the Ohio, and which,
undoubtedly, were also made by other geologists, who visited and examined that world-renowned store-
house of Devonian fossils, but of which I never found any notice in print, I am forced to the conclusion
that the silicification of the shells and corals is produced by their exposure to water and weather, and that
this process requires only a comparatively short time. Whenever, at low stages of the water, the bed of
the falls becomes dry, we find it entirely covered by fossil shells and corals, partly exposed above the solid
rock and partly inclosed in the same. All the exposed fot>sils which have been acted upon by water and
weather for some length of time are silicified, as far as they are above the matrix, while the inclosed
parts are still limestone, or, if a change in their material has already commenced, the silicification has
not sufficiently advanced to resist the dissolving power of muriatic acid, which has not the least influ-
ence upon the exposed parts. In the same condition are the fossils found in the fields near the falls
in Kentucky and Indiana. Those which are entirely weathered out, and the parts of others freed from
the matrix, are silicious, while the inclosed parts have retained their original material.

Spirifera grieri. HALL.

Plate IX., figures 8 to 14.

Spirifer grieri, Hall. Tenth Rep. on State Cab., p. 127 — 1857.
Spirifer grieri, Hall. Pal. N. Y., Vol. 4, p. 194, plates 27 and 23.

Shell gibbous, transversely oval or sub- quadrilateral, sometimes longitudi-
nally ovate, the proportion of length and breadth being very variable ; hinge-
line considerably shorter than the greatest width of the shell ; cardinal
extremities rounded. Valves sub-equally convex.

Ventral valve gibbous or ventricose ; most convex above the middle, and
nearly opposite the center of the hinge-line, and sloping somewhat abruptly
to the lateral margins, but more gently to the front ; sometimes regularly
arched from beak to front, and often arcuate in the upper part and straight in
the lower portion. Umbo prominent and much elevated above the hinge-line ;
beak more or less incurved over the fissure of the high and arcuate area, which
has a length of one-half to nearly two-thirds the width of the shell. Mesial
sinus wide and deep, sub-angular in the lower portion.

Dorsal valve regularly arcuate ; the greatest convexity near the middle, and
regularly curving to the lateral margin ; mesial fold prominent, sometimes
rounded, but usually more or less distinctly angular ; beak small, slightly
incurved over a nearly vertical narrow area. Surface marked by from six to
ten more or less rounded, simple plications on each side of the mesial fold or
sinus, while there are three or four distinctly bifurcating or dichotomous plica-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 121

tions upon the fold or sinus, giving six to eight at the margin of the shell. I
have before me a specimen of grieri, in which the first rib on each side of
the mesial fold and the second one on each side of the sinus are plainly dicho-
tomous. In perfect specimens the surface is covered by fine concentric lamel-
lose striae, which are crossed by delicate, radiating striae. This species is
distinguished from most of the allied forms by its simple, strong plications
on each side of the mesial fold and sinus, while those occupying the latter
are smaller and bifurcating.

Sometimes the middle plication on the mesial fold is simple, in which case the
fold is quite angular, while in other instances it bifurcates, leaving a longitu-
dinal depressed line on the middle, giving it a more rounded outline. It is
only on specimens which have suffered no injury by wearing or exfoliation,
that the fimbriate appearance of the concentric markings is visible. In some
of the larger and older individuals the plications are low and gently rounded,
in others they are more prominent, while from exfoliation they often become
angular and more conspicuous, and the same appears to be true of the dicho-
tomous plications of the mesial fold and sinus. The interior of the shell is
so far unknown. (Hall.)

The size of the shell differs considerably in the different specimens ; its
width is from less than three-fourths of an inch to an inch and a half, and its
length measures from less than three-fourths of an inch to an inch. The speci-
men figured on plate 9, figures 8 to 12, has a width of one inch and five-
eighths, by a length of an inch and a quarter, but specimens of these dimen-
sions are of unusually large size, and of rare occurrence.

Formation and Locality. — This species occurs in the Corniferous limestone at and near the Falls of
the Ohio, in Indiana and Kentucky; it appears in some strata pretty abundantly, though good and well
preserved specimens are somewhat rare. This species was named in honor of Judge Grier, of Dayton,
Ohio, who presented Prof. Hall with good specimens from that locality.

Spirifera hobbsi. N. SP.

Plate X., figures 21, 22, 26 to 30, and 35 and 40.
Spirifera varicosa var., Hall. Pal. N. Y., Vol. 4, p. 206, pi. 31, fig. 23.

Shell transverse, semi-oval ; width exceeding the length considerably, some-
times having its double size ; hinge-line equalling the greatest width of the
shell, and terminating in salient, mostly mucronate angles. Surface plicate.

Ventral valve much elevated, sub-pyramidal ; most prominent at the beak
or a little in front of it. The beak is not incurved, or at least only slightly
so ; mesial sinus well defined and forming a deep triangular groove, with an
acute angle in the bottom, resembling that of Spir. byrnesi, but not so much
produced at the front. Cardinal area straight and large, with sharply angular

OEOL. SUK. — 1C

1'22 PALAEONTOLOGY OF KENTUCKY.

margins, vertical and extending to the cardinal extremities, where it does not
form an acute angle, but still maintains a visible height, which is not suffi-
ciently shown in figure 29, plate 10. Triangular fissure of moderate size.

Dorsal valve very little convex, and flattened towards the cardinal extremi-
ties, and of equal size with the ventral valve. The mesial fold elevated,
rounded in the upper part, but somewhat flattened towards the front.

Surface marked by about twelve prominent and rounded or sub -angular
plications on each side of the mesial fold and sinus, which are crossed by
strong, lamellose, imbricating, concentric striae and lines of growth, which give
the shell a rugose appearance. Only the plications next to fold and sinus
reach to the apex, the lateral ones run out along the margins of the area.
Length of shell about half of an inch and even less ; its width measures from
one inch to one inch and one-eighth.

Prof. Hall has given in Pal. N. Y., vol 4, plate 31, subfigure 23, the ventral
valve of a shell which he calls, on page 206 of the same volume, Spirifera
varicosa, variety. His description is short and incomplete. His figure shows
some similarity with the present species, but it differs in its enlarged sinus
towards the front, and also by the area, which, in Hall's specimens, is partly
concave, while that of mine is always straight.

Formation and Locality. — Found in the upper strata of the Devonian limestone around the Falls
of the Ohio, in Kentucky and Indiana. It is rare, and seldom found in well preserved specimens. I
named this species after Orlando Hobbs, Esq., of JefFersonville, Ind., who is an ardent student and collector.

Spirifera knappiana. N. sr.

Plate VII., figure 14.

Shell sub-circular, gibbous ; hinge-line shorter than width of shell ; cardinal
extremities rounded.

Ventral valve gibbous in the upper part, and regularly curving to the front
and sides. Mesial sinus well defined from front to apex of beak, somewhat
shallow and rounded ; it contains two faintly marked plications. Beak of
medium size and curved over the area, which is high and concave, extending
over about two-thirds of the entire width of the shell ; fissure of medium
size.

Dorsal valve gibbous, regularly convex on the sides, a little flattened at the
cardinal extremities ; mesial fold prominent and well defined to apex of beak,
containing on its middle a well marked depression ; beak small, slightly arched
over the sub-linear area, which is somewhat concave.

Surface marked by from six to eight rounded plications on each side of
fold or sinus ; they are crossed by imbricating lines or striae, which have irreg-
ular distances in the upper part, but become regular and close set in the front

123

part. The whole surface is covered with very fine closely set radiating striae,
but there are no elongated nodes or tubercles, as in conradana.

The cardinal area is densely covered with fine vertical striae. Any one com-
paring the description of this species with that of conradana, will see that both
species agree in a great many essential characters, but, in spite of that, there
are several points of difference of sufficient value to entitle Sp. knappiana to
the full rank of a species. These points of difference are :

1. The plications in the mesial sinus and the depression of the mesial fold
found in knappiana are wanting in conradana.

2. The elongated nodes or tubercles of conradana are not possessed by
knappiana.

3. The difference between width and length is greatly less in knappiana than
in the other species.

4. The plications in knappiana are more prominent than those of con-
radana.

6. The knappiana has fine regular radiating striae instead of the tubercles
of conradana.

Some more differences might be pointed out, but I consider those enumer-
ated here fully sufficient to enable anybody, even the beginners in geological
science, to distinguish this new species from the preceding one without the
least doubt or trouble. With no other Devonian Spirifer could Sp. knappiana
be confounded ; it is, therefore, easily identified.

Formation and Locality. — This elegant species is associated with conradana, with which it is un-
doubtedly nearest related, in the Corniferous limestone of Kentucky, but it is of rare occurrence, at least
it is not represented in any collection of the Falls Cities but my own and that of Major Wm. J. Davis.
I have named it in honor of the late Dr. James Knapp, who collected, during his life-time, one of the finest
geological, or rather palseontological cabinets, not only of Louisville, but of the whole south and west.
He furnished many of the eastern prominent palaeontologists with valuable material for their palasontolog-
ical writings, and, in this manner, rendered great services to science. His collection contained a great
number of very valuable specimens of Devonian and Silurian crinoids, shells and corals, which were not
to be found in any. cabinet outside of Louisrille.

Spirifera macconathii. N. SP.

Plate XI., figures 1 to 6.

Shell transverse, sub triangular or semi-elliptical ; hinge-line much ex-
tended ; extremities often mucronate ; valves unequal in depth ; area large;
surface plicate.

Ventral valve elevated at the beak ; abruptly sloping to the front and lateral
margins, but with little convexity. Area one-third as high as long, and only
slightly concave ; fissure about twice as high as wide, and reaching to apex of

124 PALEONTOLOGY OF KENTUCKY.

valve ; beak minute. Mesial sinus well defined, but shallow, and flattened at
the bottom, with sub-angular margins rapidly widening towards the front,
where it is somewhat produced.

Dorsal valve depressed, convex, most convex above the middle ; cardinal ex-
tremities often inflected ; beak not prominent, incurving over the linear area.
Mesial fold well defined and rounded, but flattened on top towards the front.
Surface marked by from eighteen to twenty simple rounded plications on each
side of the mesial fold and sinus ; only few of these ribs reach to the beak, the
others run out on the margins of the cardinal area.

This species agrees in many points with Prof. Hall's description of Spirifera
macronata, in Pal. N. Y., volume 4, page 231, but it differs by its smaller
number of ribs, which in this species never exceeds twenty, while macronata
has from twenty-five to thirty -five. The area of macronata is straight, while
that of mcconathii is always concave, and the surface of this last species is
generally smooth, while the surface of the former is covered by several lamel-
lose imbricating lines of growth.

Formation and Locality. — Found in the upper strata of the Devonian limestone, at and near the
Falls of the Ohio, in Kentucky and Indiana. It is somewhat rare, at least in well preserved specimens.
Named after Prof. W. J. McConathy, of Louisville, Ky., who has gathered a very valuable collection of
the Devonian and Silurian fauna from the Falls of the Ohio.

Spirifera marionensis. SHUMARD.

Spirifer marionensis, Shumard. Geol. Kep. of Mo, p. 203 — 1855.
Spirifer marionensis, Hall. Geol. Rep. of Iowa, p. 511 — 1858.

Shell of medium size, nearly semi- circular, moderately gibbous ; length about
equal to two-thirds of the greatest width ; valves almost equally convex ;
hinge-line longer than greatest width of shell; cardinal extremities pointed,
and sometimes mucronate. Ventral valve broadly semi- elliptical or semi-
circular, greatest convexity above the middle ; umbo gibbous ; beak pointed
and incurved ; sinus well defined, angular and narrow at the beak, becoming
broad and shallow below, and marked by two or three dichotomizing plica-
tions ; area narrow ; sides nearly parallel and extending to the hinge-extremi-
ties, striated transversely ; foramen broadly triangular ; base greater than the
height.

Dorsal valve regularly convex ; flattened towards the cardinal extremities ;
mesial elevation very moderate, marked by two or three plications above,
which bifurcate below. Surface marked by from twelve to twenty rounded
and little elevated plications on each side of the mesial fold and sinus. Plica-
tions increasing by bifurcation either near umbo or near base.

Concentric lines of growth cover the surface, also fine radiating striae, both
of which give the shell a granulose appearance.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS.

This species is subject to some variations in different localities ; but its nar-
row, almost linear area, its mucronate cardinal extremities, its shallow sinus
and slightly elevated fold, both of which are covered by dichotomizing plica-
tions, serve to distinguish it from all other Spirifera with which it is asso-
ciated. It might be confounded with Spir. parryanus, which has its sinus
and fold also covered by dichotomizing plications* but which has only single
ribs on its lateral parts.

Formation and. Locality. — Pound in the rotten hornstone in upper portion of the Devonian for-
mation, at and around the falls, in Kentucky and Indiana. It is an exceedingly rare species ; the only
specimen known as found in our rocks was found by Major Wm. J. Davis, on the Indiana shore of the
river, just below the Falls of the Ohio.

Spirifera medialis. HALL.

Plate XXVI., figures 2 to 5.

Detthyris medialis, Hall. Geol. Kep. 4t,h Dist. N". Y., p. 208—1843.
Spirifer medialis, Hall. Tenth Report on State Cab., p. 164.

Compare Delthyris audacula, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. VIII., p. 262.
Spirifera medialis, Hall. Pal. N. Y., Vol. IV., p. 227—1867.

Shell of medium size or larger ; sub- triangular, semi-circular or semi-ellip-
tical ; hinge-line longer than greatest width of shell below; cardinal extremities
extended, often mucronate; shell moderately convex or ventricose. Surface
plicated.

Ventral valve somewhat more convex than the dorsal ; beak prominent,
elevated above the hinge-line, and only slightly incurved at the apex ; cardinal
area in our specimens of medium size, having the shape of an irregular pen-
tagon, of which the two sides at the cardinal extremities, in the specimen
before me, measure about two lines ; its margins, sloping down from the beak,
are almost straight, but sharply denned ; the area is almost flat except near
the beak, where it is slightly curved ; it is covered by longitudinal striae, and
divided in the middle by a triangular fissure, which is twice as high as wide at
its base, and which reaches to the apex of valve. Mesial sinus is of moderate
width, but rather deep ; it reaches to the apex, and' is generally rounded but
sometimes flattened at the bottom ; its margins are angular and well defined.

Dorsal valve moderately convex or gibbous ; the greatest convexity above
the middle, from where it slopes in a gentle curve to the lateral and basal mar-
gins, except at the cardinal angles, where it deflects a little, and forming a
slight depression ; beak small and slightly incurved ; area linear and well
defined. Mesial elevation prominent and sharply defined, rising abruptly at
its sides, rounded or slightly flattened on top. Surface ornamented by about
twenty-five rounded, simple plications on each side of the mesial fold or sinus,
of which the principal ones are sometimes marked by a small thread-like

126 PALEONTOLOGY OF KENTUCKY.

groove along their center, a feature most common on the ventral valve. Near
the lateral and basal margins there are several strong concentric lines of
growth, which give to that part of the surface a strongly imbricate character.
This shell is subject to many and extreme variations in the extent of the hinge-
line, convexity of the valves, height of area, and the incurving of the beak.

Formation and Locality. — Occurs in the Corniferous limestone at and around the Falls of the Ohio
in Kentucky and Indiana. It is an exceedingly rare species in our rocks ; only few specimens have been
found in Clark county, Indiana.

Spirifera mucronata, CONRAD.

Plate XXXI., figures 10 and 11.

In the collection of the late Dr. James Knapp was a Spirifera showing the
closest resemblance to Spirifera mucronata. The Doctor claimed that he found
it somewhere between Watson's Station 'and Charlestown, in Clark county,
Indiana. When he found it, he directly identified it as Spir. mucronata, and
being aware of the fact that this species had never been found here, he
marked it as soon as he reached home. I am fully convinced that the Doctor
found the specimen as he stated, but it is possible that the specimen was not
a Spir. mucronata.

The Doctor loaned the shell to me for illustration, but he took it away before
I had time to examine it more carefully. Thus I had no opportunity to gain
access to the specimen in question, and I am, therefore, not able to give a
description of said shell. If it is really a Spir. mucronata, it is certainly the
first one ever found in our rocks.

Spirifera oweni. HALL.

ft '

Plate VII., figures 1 to 10.
Spirifera oweni, Hall. Pal. N. Y., Vol. IV., page 197, pi. 29, figures 1 to 8.

Shell more or less ventricose in its different stages of growth, somewhat
transversely Oval, semi-elliptical or sub-quadrate; hinge-line about equal to
width of shell; cardinal extremities rounded or angular. Surface plicated.

Ventral valve scarcely as gibbous as the dorsal valve, its greatest convexity
above the middle of its length, and curving regularly to the margins; beak
much elevated above that of the opposite valve, and arching over the fissure,
but scarcely incurved ; mesial sinus shallow, concave, usually well defined, and
reaching distinctly to the apex. Area high, concave, elevated and continuing
to the hinge-extremities ; foramen or fissure large, reaching to the apex, and
sometimes partially filled by the thickening of the dental plates.

Dorsal valve the more gibbous, the greatest convexity in the middle, and

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 127

curving regularly to the front and lateral margins, and usually a little flattened
or sometimes concave towards the cardinal extremities ; mesial fold prominent,
rounded, with a longitudinal depressed line along the middle. Area narrow,
vertical, or in plane of the longitudinal axis.

The surface is marked by from fifteen to seventeen rounded or sub-angular
plications on each side of the mesial fold and sinus, and these are crossed by
distinct concentric striae, which become strongly imbricating, or are marked in
strong imbricating lines of growth towards the margins. In well preserved
specimens there are distinct radiating striae. In many of the silicified speci-
mens, however, both the radiating and concentric striae are partially or
entirely obliterated. The interior of the ventral valve shows two short and
rather strong teeth, with the rostal portion quite solid. The dental plates,
reaching to the bottom of the cavity of shell, curve slightly outwards and
partially inclose an oval muscular area, which in its upper part is divided by
a short medium crest. In some silicified specimens the conical spires are
partially and sometimes entirely preserved. The crura are widely separated
at their bases, and converging somewhat abruptly, curve into the dorsal valve,
making twelve or more turns, and producing a short strong spire. In well
preserved specimens the mesial fold and sinus are usually well defined, but in
some of the more gibbous forms the sinus is very broad, and one or two of the
plications on each side are involved in the sides of the depression, at the
same time the mesial fold is very prominent, rounded, and sloping almost
imperceptibly into the general contour of the convexity of valve.

This species has been generally referred to Spir. laemcosta of Lamarck, from
which it differs in being less gibbous, having a greater number of plica-
tions, and having also a depressed line along the middle of the mesial fold of
the dorsal valve. It may be easily distinguished from Spir. euruteines, with
which it is associated, by its narrower and much more arcuate area and less
angular plications. Some specimens show remains or traces of a faintly im-
pressed line along the center of each plication. (Hall.)

Formation and Locality. — Found in great abundance and beauty in the Devonian limestone in
Kentucky and Indiana, around the Falls of the Ohio. Specimens showing the internal spiral coils well
preserved in silicified shells are not very rare. This species was named by Prof. Hal! in honor of D. D.
Owen, the former State Geologist of Kentuc'

130 PALEONTOLOGY OF KENTUCKY.

length, reaching to the apex of the beak, the others are interpolations and
considerably shorter, they reach only to the umbo. The bifurcations on the
dorsal valve, and the interpolations on the other one, are so plainly marked
that they must be observed at the first glance. The fine radiating striae cover
fold and sinus as well as the other part of the valves ; towards the. front their
number is increased by interpolation, not by bifurcation. Prof. Hall mentions
concentric striae, of which I have not noticed the slightest trace, though I
possess a specimen showing the surface-markings most perfectly.
' This species has some similarity with Spir. eudora of the Niagara formation,
but it is easily distinguished from the latter by its elevated beak, its peculiar
plications, and less gibbosity.

Formation and Locality. — Occurs in the upper strata of the Niagara rocks, in the quarries east of
Louisville, Ky., where it is found in well preserved specimens; but it is extremely rare. Less than a dozen
of specimens are so far found, which belong either to my own cabinet or to that of the late Dr. James
Knapp, of Louisville, Ky., who furnished Prof. Hall with the types for his figures and descriptions. I
have never heard of its occurrence at any other place.

Spirifera radiata. SOWERBY.

Plate XXIX., figures 13, 14, 15 and 16.

Spirifer radiatus, Sowerby. Silurian System, p. 637, pi. 12.
Delthyris radiatus, Hall. Geol. Kep. 4th Dist. N. Y., p. 105—1843.
Spirifer radiatus, Hall. Pal. N. Y., Vol. 2, pp. 66 and 265—1852.
Spirifera radiata, Hall. Ind. llth Kep. of State Geologist, page 296, plate 24, figures 20 to 30—1881.

Shell variable in form, sub-triangular, rotund or sub-globose ; valves almost
equally convex ; hinge-line considerably less than the greatest width of the
shell ; cardinal extremities rounded.

Ventral valve gibbous, and curving regularly towards the anterior and lateral
margins ; greatest convexity above the middle of the valve ; mesial sinus
shallow and flat at the bottom, and, extending to the apex, it is rapidly widen-
ing towards the front, where it forms a broad extension, the termination of
which is only faintly curved. The specimen figured on plate 29 shows, in
figures 13 and 14, the termination of the mesial depression and elevation too
much curved ; this is not the fault of the draughtsman, but is caused by the
form of the specimen, of which said figures are correct copies. Generally the
mesial fold is flattened in front, causing the straight termination; but this
M-im<*n had the fold rounded to the front, which produced the strongly
curved extension.

The margins of the sinus are pretty well defined in the umbonal region, but
from there downwards they are only faintly indie* ^ft. The beak is sometimes
considerably elevated above the hinge-line, and on/y slightly curved, as in the
specimen figured, while in others the cardinal area is scarcely visible, and the

r

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 131

beaks of both valves almost touching each other. The length of the hinge line
is so variable that in some specimens it almost equals the greatest width of
the shell, while in others it is so much reduced that it, in connection with the
rounded extremities, and beaks touching each other, leaves its generic position
doubtful. Such specimens show nearer relation to Atrypa than to Spirifera.
The triangular lissure is also variable ; sometimes it is broad in the base, some-
times long and narrow ; in some specimens it is open, in others partially or
entirely closed by a pseudo-deltidium.

Dorsal valve is almost as gibbous as the other valve ; its greatest convexity
is below the umbo, from where it regularly but gently curves to the anterior
and lateral margins. The mesial fold is arcuate from beak to front, pretty
well defined in its upper portion, but very slightly or not at all towards the
front ; it is rounded above the middle of the valve, but flattened and sometimes
even a little depressed in the basal half ; beak incurved over the linear area.

Surface marked by regular fine radiating striae, which cover also the mesial
fold and sinus, some of which bifurcate or dichotomize towards the front.
Prof. Hall, in his description of this species in the Indiana Report, states, that
of these striae, eight or more occupy the space of a line, that the radii are
flattened, and that the interspaces are only about half as wide as the striae.
The specimen before me, the same figured on plate 29, which I found in the
quarry near the new water- works, east of Louisville, and which shows the
surface-markings as perfect as possible, agrees as to the number of striae in
the space of a line, but it differs as to the balance of Prof. Hall's observation.
In my specimen the striae are not flattened, but plainly rounded, and the
interspaces are certainly as wide, if not wider, than the radii. It appears to
me that the Waldron specimens differ in some respects slightly from those of
our strata. I have a good many Waldron shells before me ; they show finer
and closer set striae than the Kentucky specimens.

In size this species is as variable as any other Spirifera, or even more so.

In the quarries near our city we generally find the Spir. radiata of small
dimensions, some measuring only three -eighths of an inch in length and one-
half of an inch in width, while the specimen figured is about one of the
largest found near Louisville, and specimens of this size are extremely rare.
In the Niagara limestone near Waldron, Ind., we find specimens of an inch
and a quarter in length by a width of an inch and a half.

Formation and Locality. — Found in the Niagara limestone east of the city of Louisville, and on
the opposite bank of the Ohio river in Indiana. But the finest and most perfect specimens of this species
are found, even abundantly, near "Waldron, Indiana.

132 PALAEONTOLOGY OF KENTUCKY.

Spirifera sculptilis. HALL.

Plate XXXI., figure 13.

Delthyris sculptilis, Hall. Geol. Kep. of 4th Dist. N. Y., p. 202—1843.
Spirifera sculptilis, Hall. Pal. N. Y., Vol. 4, p. 221, pi. 35—1862-1866.

Shell gibbous ; valves sub-equally convex, semi-elliptical or sub-triangular ;
hinge-line longer than greatest width of shell, and prolonged into mucronate
extensions ; length about one-half the width on the hinge-line. Surface
coarsely plicated.

Ventral valve regularly convex, arcuate ; beak arcuate over a sub-linear area
of moderate height, extending to the limits of the cardinal line : mesial sinus
strongly defined, sub-angular.

Dorsal valve regularly convex, the greatest convexity in the middle, and
regularly arcuate from beak to base; mesial fold abruptly and strongly
elevated, with the summit flattened or grooved ; beak incurved; area very
narrow.

Surface strongly marked by three, four or five abruptly elevated angular,
plications on each side of the mesial fold and sinus, leaving a somewhat wide
corrugated space at the cardinal angles. The plications bordering the sinus
are stronger, more elevated, and continuing distinct quite to the apex. The
shell is concentrically marked by strong, imbricating lamellose striae, which
are abruptly bent backwards, and much elevated in crossing the plications,
giving them a sub-nodose character. In the bottom of the sinus these striae
have often a distinct backward bend, with a slight elevation indicating an
incipient plication, which corresponds with the depression in the mesial fold.
This species is readily recognized by its few strong plications, and the wide
space at the cardinal extremities marked only by the concentric striae. (Hall.)

Formation and Locality. — Found in the upper strata of the Devonian formation, around the falls,
in Kentucky and Indiana, where it is of very rare occurrence. My figure is taken from a very fine and
well preserved ventral valve, showing the inside and the hinge in perfect order. This specimen I found
at the Falls of the Ohio, in the so-called rotten hornstone, which furnishes the best preserved fossils.

Spirifera segmenta. HALL.

Plate XIII., figures 36, 37 and 38.

Spirifer segrHentus, Hall. Tenth Kep. on the State Cab. — 1857.
Spirifer segmentus, Hall. Descript. of New Pal. Fossils, p. 91 — 1857.
Spirifera segmenta, Hall. Pal. N. Y., Vol. 4, p. 207, plate 31.

Shell transverse, semi-oval; length less than half the width; hinge-line
equalling the greatest width of shell, and terminating in salient angles. Sur-
face plicate.

Ventral valve much elevated, sub-pyramidal, most prominent at the beak,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 133

which is not, or at least very seldom, incurved ; mesial sinus strongly defined,
shallow and nearly flat in the bottom ; its sides are straight, which give it a
triangular form, in which the sides are about once and one-half as long as the
base. Area very large, with sharply angular margins, and greatly inclined
forward, and nearly of the same size as the exterior of the valve ; the fissure
is high and large, almost equalling in size the mesial sinus.

Dorsal valve depressed, convex and flattened towards the cardinal extremi-
ties, larger than the ventral valve, semi-elliptical in form, with a low but
sharply defined mesial fold, which is barely flattened upon the summit. The
proportions in height of area, length of ventral and length of dorsal valves, is
about as five, six and seven.

Surface marked by twenty or more simple, rounded or sometimes sub-angu-
lar plications on each side of the mesial fold or sinus, the lateral ones of which
do not reach the beak, but run out along the margins of the area. In its per-
fect condition the shell has been marked by fine concentric striae, traces of
which are still preserved, together with stronger imbricating lines of growth.
(Hall.)

This species is associated with Spir. varicosa, and its younger and smaller
specimens may sometimes be mistaken for those of that species ; But Spir.
segmenta differs from Spir. varicosa in the following points :

1. In Spir. segmenta the area is always straight and greatly inclines towards
the front, which easily distinguishes it from almost any other species of Spiri-
fera, except some forms of euruteines. In Spir. varicosa the cardinal area
is markedly concave and stands at right-angles to the margins.

2. Spirifera segmenta has twenty and more plications on each side of the
mesial fold and sinus, while Spir. varicosa has only from eight to ten ribs in
each half of each valve ; then, again, the plications of segmenta are always
smoother than those of varicosa.

3. In Spir. segmenta the dorsal valve exceeds in size the ventral valve, which
is not the case in Spir. varicosa.

Besides these, there are several other differences which the student of palaBon-
tology will soon find, whenever he closely examines numerous specimens of
both species.

The older and larger specimens of this species resemble some Spir. euruteines,
but it is easily distinguished from euruteines by the frontward inclination of
its area, by its greater transversity, by its smaller size and more numerous
plications, and by its dorsal valve exceeding in size the ventral one. All three
species are found associated, and the Spir. segmenta forms a kind of connect-
ing link between the two other species.

Prof. Hall states that Spir. segmenta finds its nearest analogue in Spir.
angusta of the Hamilton group, and indicates that both species might be

154 PALEONTOLOGY OF KENTUCKY.

identical. Specimens in the collection of the late Dr. James Knapp, marked
by Prof. Hall himself as Spir. angusta, can not be distinguished from Spir.
segmenta. If his original Spir. angusta are really identical with those marked
by him as of the same species in Dr. Knapp' s cabinet, we must consider seg-
menta and angusta as belonging to one and the same species. Both are origi-
nally described by Prof. Hall in his tenth report on the State Cabinet, in 1857,
and it is therefore difficult, if the identity of segmenta and angusta should be
proved, to decide which of them ought to be placed among the synonyms.
Inasmuch as Spir. segmenta is described in said report on page 131, while the
description of Spir. angusta appears on page 164, the name segmenta has pre-
cedence over angusta.

But those specimens marked by Prof. Hall do not at all agree with his
figures in the 4th volume of the Pal. of New York, and it is, therefore, possi-
ble that he made a mistake in his identification. I have never found a Spirifer
in our strata that agreed fully with Hall's figures of Spir. angusta, where the
cardinal area inclines so much forward, and where the cardinal extremities are
so mucronate. If Spir. angusta holds good as a species, it has, as far as I
know, not been found near the Falls of the Ohio.

Formation and Locality. — Spir. segmenta is found in abundance, and as well preserved specimens,
in the Coruiierous limestone of Kentucky and Indiana, at and around the Falls of the Ohio river.

Spirifera varicosa. HALL.

Plate X., figures 11 to 20, and 23 to 25.

Spirifer varicosns. Hall. Tenth Rep. on the State Cab., p. 130 — 1857.
Spirifer varicosus, Hall. Description of New Pal. Fossils, p. 90 — 1857.
Spirifera varicosa, Hall. Pal. N. Y., Vol. 4, p. 205, pi. 31.

Shell somewhat semi-circular or semi- elliptical ; length equalling or less than
half the width; hinge- line equal to greatest width of shell, and terminating
in salient angles or mucronate extensions. Surface plicated.

Ventral valve much the more convex ; greatest elevation at the umbo, and
regularly curving to the front and to the lateral margins ; mesial sinus strongly
defined, rather flat in the bottom ; beak slightly arcuate ; area high, nearly
flat below, and slightly concave towards the apex.

Dorsal valve moderately convex, with a prominent, abruptly elevated mesial
fold, which is flattened on the summit, and sometimes slightly depressed along
the center ; the beak projecting a little above the hinge-line, and over a narrow
area gently incurved.

The surface is marked by from eight to ten simple and somewhat abruptly
elevated plica tions on each side of the mesial fold or sinus; they are crossed
by strong lamellose, imbricating lines of growth, which give a varicose charac-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 135

ter to the surface, and where the shell is exfoliated the plications are nodose.
In some specimens, distinct, fine radiating striae can be observed, but this is
of rare occurrence. There is often a retrorse curving of the concentric striae
in the center of the mesial sinus, and sometimes a slight elevation on that line.
(Hall.)

Prof. Hall, who first described this species, compares it with Spirifera euru-
teines of Owen. In regard to size, the euruteines is almost twice as large as
the varicosa, at least we find plenty specimens of the former species which
have double the width of the latter one. Spir. varicosa is always more trans-
verse, that is, the excess of its width over its length is considerably greater
than the excess of the width over the length in Spir. euruteines. In Spir.
varicosa the plications are more angular, and the concentric lines of growth
greatly stronger than in Spir. euruteines. It differs from the latter also by its
abrupt and angular mesial fold. This species shows very little variations in

the more than one hundred specimens before me.

/

Formation and Locality. — Found in great abundance, and in most perfectly preserved specimens,
in the Corniferous limestone around the Falls of the Ohio, in Kentucky and Indiana.

Genus Trematospira. Han.

Trematospira, Hall. Pal. N. Y., Vol. 3, page 207—1859.

Etymology : trema, a foramen; spira, a spire; alluding to the perforation in the beak of the ventral valve.

Shell transverse, elliptical or sub-rhomboidal, furnished with internal spires
(arranged as in Spirifera) ; hinge-line shorter than width of shell ; cardinal
angles rounded. Valves articulated by teeth and sockets ; beak of ventral
valve produced or incurved, and truncated by a small, round perforation,
separated from the hinge-line by a deltidium. A deep triangular pit or fora-
men, beneath the beak of ventral valve, which is filled by beak of the dorsal
valve. False area sometimes defined. Surface marked either with strong,
simple plications or finer fasciculate or bifurcating striae, which cover also
the mesial elevation and depression. Shell structure punctate. (Hall.)

In the extension of the hinge-line, the mesial sinus, the internal spires, and,
partly, in the exterior markings, this genus resembles Spirifera and Spiriferina.
In the perforate beak, false area and incurving of the dorsal beak beneath
that of the other valve, it resembles Atrypa, while one species has the gen-
eral aspect of Rhynchonella. The broad triangular foramen for the recep-
tion of the dorsal beak is a constant and conspicuous feature of this genus.

136 PALEONTOLOGY OP KENTUCKY.

Trematospira hirsuta. HALL.

Plate XVI., figures 15 to 19.

Atrypa hirsuta, Hall. Tenth Kep. on State Cabinet, p. 108 — 1857.
Trematospira hirsuta, Hall. Thirteenth Kep. on State Cab., p. 101 — 1860.
Athyris (?) chloe, Billings. Canada Journal, p. 282—1860.
Trematospira hirsuta, Hall. Pal. N. Y., Vol. 4, pp. 274 and 275—1867.

Shell of medium size ; sub-elliptical, in very old specimens sub-circular or
sub-quadrate ; moderately convex when young ; increasing in convexity with
increasing age, and finally becoming gibbous ; sinus and fold wanting in young
shells, appearing at a certain age, and becoming prominent in old individuals,
which assume in outline the exact shape of Athyris vittata.

Ventral valve moderately convex, with greatest convexity at the umbo, from
where it slopes somewhat abruptly to the cardinal margins, and gently to the
lateral and basal margins ; the umbo is prominent and the beak incurved ; a
mesial sinus is indicated in young shells ; it becomes more definite with age,
but remains, even in very old specimens, shallow ; this sinus is undefined in
its margins, which are rounded, and which coalesce with the general surface
of the valve, and it does never extend further back than to a little behind the
middle of shell.

Dorsal valve of about equal convexity with the ventral, except in old speci-
mens, in which it is considerably less ; greatest convexity above the middle of
the valve, from where it slopes in a gentle curve to the sides and front ; umbo
flat, but becoming more prominent with age, and the beak strongly incurving
into the other valve beneath its circular foramen ; a mesial fold is only indi-
cated in young specimens, it becomes somewhat more prominent in older
shells, but never attains more than a moderate elevation, and is undefined in
its margins, which are rounded, and run gradually into the general surface of
shell.

Surface ornamented by from thirty to forty simple, low, rounded, radiating
striae, which increase from beak to front in size and distance ; these radiating
striae are crossed by fine, concentric lines of growth, and more distant imbri-
cating lamellae. The surface of the specimens, as they are usually found,
is granulose ; but in perfectly preserved shells it is covered by minute setae or
spinules, the bases of which remaining, give the papillose character. The
entire shell structure is punctate.

The specimen illustrated is of more than average size ; in its proportion of
width to length, it is more transverse than the usual form ; but at the time
when the drawings were made it was the only specimen at my disposal.

Formation and Locality. — Found in the rotten hornstone of the Corniferous group, in a quarry in
the eastern portion of the city of Louisville. Formerly very rare, but of late a good many very good
specimens have been found, so that my collection embraces now, at least, a dozen fair individuals.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 137

Trematospira helena. ». SP.

Plate XXXII., figures 40 to 43.

Shell very small, broadly ovate or sub-globose, very gibbous ; somewhat
longer than wide ; greatest width below the middle of the length, but not as
near the base as shown in the figures 40 and 41. Surface plicated.

Ventral valve regularly curved from beak to base ; greatest convexity at the
middle of the valve, from where it slopes in a regular curve to lateral and basal
margins, but rather abruptly to cardinal lines ; beak in proportion to the size
of shell prominent, elevated and incurved over that of the opposite valve;
the place of the apex is occupied by a round, plainly visible foramen ; lateral
and basal margins form a regular curve, with a slight emargination in the
central portion of the base, which is not shown in figures 40 and 41 ; from the
umbo to the front a mesial depression is marked.

Dorsal valve equal in convexity to the other ; most prominent at the mid-
dle, and curving regularly to side and front margins, but more rapidly to the
cardinal line. This valve has also a mesial depression indicated ; its umbo is
prominent, and its beak strongly incurved into the opposite valve below the
foramen of the same.

Surface is marked, in proportion to the size of the shell, by very strong,
rounded plications, all of which, with the exception of those in the mesial
depressions, reach to the beak ; the ventral valve has five and the dorsal valve
four on each side of the sinus. The sinus of the ventral valve has in its bot-
tom a greatly smaller plication, which starts at the lower side of the umbo,
and bifurcates at about the middle of its length ; in some shells the mesial rib
does not dichotomize. The plication in the mesial depression of the dorsal
valve is also somewhat smaller than tfre others, but the difference in size is not
so marked as in the ventral valve, and consequently the mesial sinus of the
dorsal valve is not as conspicuous as that of the ventral. This mesial rib of
the dorsal valve starts at the beak, and bifurcates below the umbo ; both prongs
attain at the base almost the same strength as the adjacent ribs, thus leaving
in a front view of the shell only a faint indication of the dorsal sinus. All
these radiating plications are crossed by fine, closely set, lamellose concentric
lines of growth, which give the surface a somewhat rugose appearance. The
figures, which are very defective in not representing important features of this
beautiful little shell, are enlarged to about double size.

Formation and Locality. — Found in the lower strata of the Niagara group (which by some geolo-
gists are placed in the Clinton group), in the quarries east of the city of Louisville, Ky. It is exceedingly
rare, only three, but very fine specimens, are in my collection, while I have never seen it in any other
cabinet. This shell has a close resemblance to Trem. globosa, Hall, from the Lower Helderberg group,
GKOL. SUR. — 18

138 PALEONTOLOGY OF KENTUCKY.

from which it differs, however, by its smaller size and smaller number of plications ; our shell has only ten
ribs on each valve, while that species has, according to Prof. Hall, from twelve to sixteen ; then, again,
our specimen has only one rib, which bifurcates below in the depressions, while Tr. globosa has always
two, often three, in said depressions.

Genus Zygospira. Han.

Zygospira, Hall. 15th Regent's Keport, 1862.
Etymology : zygos, a yoke ; spira, a spire.

This genus was established by Prof. Hall to receive such forms as Zygospira
modesta, Z. cincinnatiensis and Z. headi.

Z. modesta is made the type of the genus, which has great similarity to Z.
kentuckiensis, and which latter, therefore, presents the main characteristics of
the genus. The original description of this genus, by Prof. Hall, is cited from
his 15th Regent's Report. It is to be regretted that Prof. Hall's valuable
writings are scattered through such a great number of scientific periodicals
and State reports.

Zygospira kentuckiensis. ». SP.

Plate XXXIV., figures 21 to 25.

Shell rather large, as compared with other species of Zygospira ; sub-circular
or sub -elliptical ; from moderately convex to gibbous ; cardinal lines sloping
towards the front, forming a very obtuse angle at the beaks ; lateral margins
regularly curved; front broadly rounded, with a straight or sinuate central
part. Ventral valve larger than the dorsal ; central part elevated, and forming
a mesial fold, extending from beak to front, not defined at its margins, and of
moderate elevation. The middle line of this fold is marked by a somewhat
broader and deeper furrow, towards which both sides of the fold slightly in-
cline, thus forming a small mesial sinus on the top or summit of the fold ; this
central depression on the fold extends also from the beak to the front. The
lateral slopes of the mesial fold are more or less abrupt, and the surface be-
tween fold and sides becomes flat and even somewhat concave ; the umbo is
prominent and the beak pointed, and, in most shells, closely incurving upon
the beak of the opposite valve, concealing entirely the hinge-area and its fora-
men.

In a few specimens in my collection the beaks of both valves are sufficiently
apart to show a small ventral hinge-area, with a small triangular fissure.

The dorsal valve is moderately convex in its lateral parts ; its central portion
is depressed, forming a mesial sinus, which extends from the apex to the
front, and increases gradually in depth and width towards the base ; the umbo
is inflated, and the beak minute and incurved. The surface is covered by

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 139

simple, rounded or sub-angular, radiating plications, all of which, with the
exception of a few near the lateral margins, extend back to the beak; they
increase gradually in strength and in the size of their interspaces towards the
front. The size and number of these plications is variable in different speci-
mens.

The two shells illustrated on plate 34, of which one is shown in figures 21,
22 and 23, and the other in figures 24 and 25, are so different in form and in
the size and number of the ribs, that I would be justified to put them in dis-
tinct species ; but there are so many intermediate forms connecting these two
extremes, which compel me to place them both in the above named species.
These shells have a somewhat close resemblance to Zygospira modesta, and
are considered by some geologists to be merely a larger and robust form of
that species ; bat it differs from that little shell not only by its size, which is
often more than twice that of Z. modesta, but also by its convexity, which
often increases to gibbosity, and also by its general aspect. I have collected
several hundreds of this shell ; I found them of all sizes ; some very large, as
shown in the illustrations, and again others very small, not exceeding the Z.
modesta in size ; but even these small or young shells differed so much in their
whole appearance from Z. modesta, that I think it necessary to separate our
shell from Z. modesta and place it in a new species to be named Z. kentuck-
iensis.

Formation and Locality. — I collected this fine shell in different places in Oldham county, Ky., but
I found it in great abundance at Taylor's Station, in said county, on the Shelbyville railroad, in the shales
of the Hudson Kiver or Cincinnati group.

Genus Streptorhynchus. King.

Streptorhynchus, King. Monogr. of Perm. Fossils — 1850.
Etymology: strepto, I bend or twist; rhynchus, a beak.
Copied from Hall's Pal. N. Y., Vol. 4, page 64—1867.

The shells of this genus are semi-circular or semi-elliptical, concavo-convex
or plano-convex, and sometimes bi-convex. They are externally striated, with
rounded bifurcating striae, which are crossed by fine concentric lines ; and in
some forms the stronger striae are distant, with finer radiating and concentric
striae cancellating the intermediate spaces. The ventral beak is sometimes
produced and bent or twisted, and the fissure beneath the beak is closed or
partly closed by a solid deltidium, while the area is subject to great variations.
A narrow area often exists on the dorsal valve, but this is not a constant char-
acter. This genus is very closely allied to Strophomena, the most obvious
external character by which the former is distinguished being the irregular
twisting of the beak of ventral valve.

140 PALAEONTOLOGY OF KENTUCKY.

Streptorhynchus arctostriata. HALL.

Plate XXXI., figures 31, 32 and 33.
Orthisina arctostriata, Hall. 13th Reg. Report — 1860.
Streptorhynchus arctostriata, Hall. Pal. N. Y., Vol. 4, p. 71—1867.

Shell of medium size, semi-circular or semi-elliptical, frequently unsymmet-
rical ; the proportion of length to width differs in different specimens ; hinge-
line straight, differing in length in different individuals, but in the average
about equal to the greatest width of the shell ; lateral margins meet the car-
dinal line usually at right-angles; they have generally a compound curve,
concave in the upper, and convex in the lower half. Ventral valve more or
less convex towards the urn bo, and sometimes in the middle, being more or
less flattened towards the sides and front of the shell ; beak often distorted ;
area straight, triangular and well defined in its margins ; inclines sometimes
forward, and again, in other specimens, backwards ; it is often unequal in its
two sides as divided by the triangular fissure, which is closed by a strong con-
vex deltidial plate.

Dorsal valve depressed convex, but in some shells, partly in consequence of
distortion, markedly ventricose, with a narrow or linear area. Surface orna-
mented by sharp, close, radiating, crenulated striae, which increase mainly
by interpolation or interstitial addition.

This shell is very variable in its main characters ; its beak, generally dis-
torted, is sometimes exactly straight; the cardinal area, unequal in most
specimens, is, in some individuals, fully symmetrical ; the ventral valve is, in
most of our shells, crushed, and consequently does not show its original form ;
while the dorsal valve of our specimens is, even in individuals not distorted,
considerably convex, instead of the flat or slightly concave dorsal valve of
eastern shells of this species.

Concentric lines of growth are more or less shown on different shells.

Formation and Locality. — Found in the upper strata of our Devonian formation, which by Prof
Hall are considered as belonging to the Hamilton group ; it is a rare shell, and to my knowledge, so far,
never found undistorted. The specimen illustrated on plate 81, figures 32 and 33, represents about the
largest size attained by this species, at least in our rocks.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 141

Streptorhynchus subplaims, CONRAD.

Plate XXIX., figures 11 and 12.

Strophomena subplana, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. 8 — 1842.
Leptaena. subplana, Hall. Pal. N. Y., Vol. 2. p. 259—1852.
Streptorhynchus subplana, Hall. Trans. Alb. Inst., Vol. 4, p. 226 — 1863.
Streptorhynchus subplana, Hall, llth Indiana Keport, p. 288 — 1881.

Shell of medium size; plano-convex, semi-elliptical; length and width often
equal, but sometimes the latter exceeds the former considerably ; hinge-line
is generally longer than the width of shell below ; cardinal extremities are
always somewhat produced, but in some instances they become even nmcro-
nate.

Ventral valve moderately convex ; its greatest convexity a little above the
middle, from where it slopes gently to the lateral and basal margins ; the car-
dinal extremities are deflected and forming a slight depression, extending from
the cardinal line obliquely to the lateral margins, intersecting these about one-
third the length of the shell from the cardinal extremities ; beak is small and
not incurved. The foramen is closed by a deltidium. The area extends to the
extremities, but is narrow.

Dorsal valve is less convex than the other ; it is in our specimens almost
plane, with the exception of the umbonal region and the cardinal angles, both
of which are slightly convex, the umbonal region by a natural elevation, and
the cardinal angles by a downward deflection of the extremities.

Cardinal area narrow, but about as large as the area of the other valve.
Both valves meet under an angle of about sixty degrees.

The surface is covered by numerous single thread-like radii, which increase
by intercalation but not by bifurcation. The intercalated striae are smaller
than the original ; they become equal at the margin. These radii are crossed
by fine concentric striae, and by a few marked concentric lines of growth,
generally two in number, dividing each valve into three concentric zones. Our
specimens differ somewhat in shape from those found at Waldron, Indiana.
Ours are somewhat wider in proportion to length, and the extremities are more
produced. The size of different specimens differs greatly; the one illustrated is
of about maximum size, as found in our rocks.

Formation and Locality. — Occurs in the Niagara rocks in the quarries south-east of the city of
Louisville, Ky., where it is a rather rare species. Very fine specimens are found abundantly in the Niag-
ara rocks of Waldron, Indiana.

142 PALAEONTOLOGY OF KENTUCKY.

Streptorhynchus temris HALL.

Streptorhynchus tennis, Hall. Trans. Alb. Inst., Vol. 4, p. 210 — 18(53.
Streptorhynchus tennis, Hall. 28th Regent's Kep., p. 150 — 1879.
Streptorhynchus tenuis, Hall, llth Geol. Rep. of Ind., p. 287 — 1881.

Shells found at Waldron, large ; those found in the rocks near Louisville of
medium size; semi-circular or broadly semi-elliptical; cardinal line less than
greatest width of shell ; cardinal extremities rounded.

Ventral valve moderately convex at the umbo and the umbonal region, extend-
ing over about one-third of the whole surface of the valve ; balance slightly
concave ; cardinal area narrow, but increasing in height at the beak and near
it ; beak elevated and straight ; triangular fissure of moderate size and closed
by a deltidium.

Dorsal valve moderately convex ; umbo very small ; surface depressed near
the cardinal extremities, and also near front margin.

Surface ornamented with radiating striae of -different size, all fine and
rounded, but alternately large and small, which are strongly curved on the
lateral portion of shell. These radii are crossed by fine concentric striae, which
give surface of shell, under lens, a beautiful rugose character. The substance
of the shell is very thin. Large specimens of this species are found at Wal-
dron, Indiana, of which one individual, according to Prof. Hall's statement,
measures forty millimeters in length, by fifty millimeters in width. The speci-
men before me being the only one found in our rocks, measures nine lines in
length by fourteen lines in width.

Formation and Locality. — Found in the Niagara limestone at Waldron, Indiana, and in the quar-
ries east of the city of Louisville, Ky. It is very rare ; only few specimens are so far found at Waldron,
and but one at Louisville j this last one belongs to my collection.

Genus Strophodonta. Han.

Strophodonta, Hall. Pal. 1ST. T., Vol. 2, p. 63—1852.
Etymology : strophos, bent ; odous, tooth.

Shell with general form and characters of Leptaena; one valve convex, the
other one concave ; the concave one following the general curve of the other,
and being nearly parallel with the same. Cardinal area continuous, nearly
linear, mostly occupied by the dorsal valve, striated transversely; foramen
decidedly closed ; ventral valve with the hinge-line uninterrupted ; margins of
the hinge-line crenulated ; area strongly striated in the transverse, and more
slightly in the longitudinal direction. Muscular impressions somewhat bilat-
eral.

The crenulated hinge-line is a very strong distinctive character, since in

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 143

Leptaena this margin is smooth. In true Leptaena, also, the area is striated
only longitudinally, that is, in the direction of the hinge-line, and the foramen
is in part occupied by a projection of the ventral valve, which fills it, while in
Strophodonta the foramen, if it ever existed, is entirely closed by the growth
of the dorsal valve, and the hinge-line of the ventral valve is straight and con-
tinuous. The striae of the shell in many species of Strophodonta differ from
those of Leptaena, and some of the species are readily distinguished by this
character alone.

The chief peculiarity of the shells belonging to Strophodonta is the absence
of a foramen in area of the ventral valve ; otherwise, they do not differ from
Strophomena, which may hereafter take the place of Strophodonta.

Strophodonta demissa. CONRAD.

Plate XVIII., figures 10 to 16, Plato XXXIII., figure 22.
Strophodonta demissa, Conrad. Journ. Acad. Nat. Sci. Phil., Vol. 8 — 1842.
Strophomena (Strophodonta) demissa, Hall. 10th Reg. Rep., p. 137 — 1847.
Strophodonta demissa, Hall. Rep. Geol. Sur. of Iowa, p 495 — 1859.
Strophomena demissa, Billings. Canadian Journal — 1861.
Strophomena demissa, Billings. Geology of Canada, p. 367 — 1863.
Strophodonta demissa, Hall. Pal. N. Y., Vol. 4, page 101 — 1867.

Shell semi-elliptical, usually somewhat wider than high, but in some speci-
mens both dimensions are equal ; hinge-line about equal to greatest width of
shell, sometimes differing from it by being either a little larger or smaller.
The shell is often a little contracted below the cardinal extremities, which
are sometimes auriculate. In some of the specimens, the lateral margins are
nearly straight and parallel for more than half the length of shell, while the
lower parts of the sides and the base form a regular curve.

Ventral valve regularly convex ; greatest convexity a little above middle of
the length, from where it slopes in a regular curve to the lateral and basal
margins ; between the umbo and the cardinal extremities is a slight depression,
which only runs a short distance from the cardinal line into the body of the'
valve, and which is sometimes confined to the mere deflection of the cardinal
extremities ; umbo is small, but well expressed, and the beak is slightly in-
curved, and reaches somewhat beyond the plane of the ventral area.

Dorsal valve is moderately concave, and corresponds in the general form of
its depression with the convexity of the ventral valve. The area of the ventral
valve is very variable in specimens from different localities, but in our shells it
is of moderate size, forming a low triangle, and being curved below and on
both sides of the beak ; it is covered by fine transverse, and still finer longitu-
dinal lines ; no foramen or fissure is indicated ; the inner margin of the area is
crenulated in its whole extent. The dorsal area is considerably smaller than

144 PALEONTOLOGY OF KENTUCKY.

the ventral ; it is very narrow, almost linear. The planes of the two cardinal
areas are inclined to each other in such a manner as to form an angle of more
than ninety degrees ; this angle of the areas is, however, different in one and
the same specimen according to the distance from the cardinal extremities ;
near the latter it is smallest and increases gradually, sometimes rapidly, to-
wards the beaks, below which, in some individuals, they form no angle at all,
but fall ih one and the same plane.

The surface of both valves is ornamented by radiating and concentric striae.
Of the radii, some ten to twelve are much stronger and more elevated than the
balance, but they maintain their prominence only inside of the umbonal region;
leaving this, they bifurcate directly, which process is repeated about half-way
between umbo and front ; in addition to this increase by bifurcation, a further
enlargement in the number of finer radii is attained by the intercalation of
radiating striae, some of which reach even into* the umbonal region, between
the before mentioned prominent costae, while others set in a little above the
second bifurcation ; thus the marginal portion of the valve is covered by
numerous fine striae.

The dorsal valve is covered by a similar system of striae, with the only
exception, that in this valve, between the first and second bifurcation of one
and the same radius, is only a short distance. In well preserved specimens
the entire surface of both valves is covered by fine concentric lines of growth,
some of which are more prominent, and divide the surface into concentric
zones. In most of the shells these concentric lines, with the exception of the
most marked ones, are obliterated by either silicification or exfoliation. Shells
from different localities show considerable variation in form and size. Our
shells, although differing in size, are uniform in shape and in the ornamenta-
tion of their surface. With very few exceptions, they have all a brownish-red
color, which is entirely superficial, not penetrating into the body of the shell
to any extent.

» Formation and Locality. — Occurs rather abundantly in the upper strata of the Devonian forma-
tion, in Jefferson county, Ky., and in Clark county, Indiana. Verj- fine and well preserved specimens are
found, lacking only the fine concentric lines of growth. The illustrations on plate 18 represent the differ-
ent sizes of the shell as found in our rocks, and figure 22, plate 33, a very young specimen.

Strophodonta hemispherica. HALL.

Plate XVIII., figures 4, 5 and 6.

Strophomena (Strophodonta) hemispherica, Hall. Tenth Keport on St. Cab., p. 113 — 1857.
Strophodonta hemispherica, Hall. Pal. N. Y., Vol. 4, p. 90—1867.

Shell of large size, sub-hemispheric, semi- elliptical in outline ; hinge -line
equal or greater than maximum width of shell; cardinal extremities always

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 145

angular, sometimes salient and auriculate ; length smaller than the width,
their proportion about as four to five. The largest specimens measure about
two inches in length, by two inches and a half in width. Ventral valve is very
gibbous ; its depth is sometimes equal to half of its length. The point Of
greatest convexity below the middle of the length, from which it slopes rapidly
or rather abruptly to the front, and to the basal half of the lateral margins,
while it curves gently to the cardinal lines.

The umbo is more or less elevated, and the beak incurved. The cardinal
area is narrow, and its margin crenulated.

Dorsal valve shallow, concave in its larger portion, and only more abruptly
deflected in a marginal strip surrounding basal half of the valve, which strip
becomes sometimes even geniculated.

Surface is ornamented by fine radiating striae, which are somewhat unequal
on the upper and middle portions of the ventral valve, but are fine and regular
towards the margins. In some specimens of the dorsal valve the striae show
a tendency to the alternation of three or four finer ones with a distinctly
stronger one between ; but this feature is not prevalent ; most shells have the
striae or their dorsal valve fine, close, and nearly equal in strength. Fine con-
centric lines cross the radii in well preserved specimens, but they are usually
obliterated. Four or five marked wrinkles extend obliquely from the cardinal
extremities into the body of the valve, but reach only to the base of the umbo.
This species diifers from St. inequiradiata by its larger size and greater gib-
bosity ; while, according to Prof. Hall' s statement, it is so nearly allied to
Stroph. concava, that it probably belongs with that shell in one and the same
species.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation in Jeffer-
son county, Ky., and in Clark county, Indiana. The specimens for the figures 7, 8 and 9, on plate 18,
seem to be an internal cast of Strophodonta hemispherica.

Strophodonta mequistriata. CONRAD.

Plate XVII., figures 10 and 11.

Strophomena inequistriata, Conrad. Jour. Acad. Nat. Sci. Phil. — 1842.
Strophomena inequistriata, Hall. Geol. Kep. 4th Dist., p. 290 — 1843.
Strophomena (Strophodonta) inequistriata, Hall. 10th Keg. Kep., p. 142 — 1857.
Strophodonta inequistriata, Hall. Pal. of N. Y., Vol. 4, p. 106—1857.

Shell semi-oval or somewhat semi elliptical or semi-circular in outline ; hinge-
line extended beyond width of shell below ; cardinal extremities acute, some-
times mucronate. In the specimen before me, which is illustrated on plate 17,
figure 10, the lateral margins below the mucronate extremities, and the basal
margin, form a regular curve,

GEOL. SUE. — 19

146 PALEONTOLOGY OP KENTUCKY.

Ventral valve moderately convex, becoming more gibbous in its center por-
tion from umbo to front ; greatest convexity a little above the middle of the
valve, from where it slopes in a regular curve to the front or base, and to the
basal half of the lateral margins ; to cardinal line and to the rear half of the
lateral margins it slopes more rapidly ; the cardinal angles are reflected, by
which a shallow concavity is formed between them and the umbo ; the beak is
little elevated above the hinge-line and slightly incurved ; the cardinal area is
narrow, extending to the extremities, and striate vertically.

Dorsal valve concave, differing greatly in its depth in different individuals ;
but usually its concavity corresponds in general form with the convexity of the
ventral valve ; hinge-area very narrow, almost linear, and of not more than
half the height of the ventral one ; no beak is observed in this valve.

Surface is ornamented by radii of different size and character, as may be seen
in figure 11, plate 17. Some of these striae are more prominent, most of which
extend to the beak, but some are added by intercalation ; the interspaces be-
tween these stronger striae are filled by finer ones, which are scarcely visible to
the naked eye ; all the radii are crossed by fine concentric striae. The general
surface character of the convex valve is much like that of good specimens of
Strophomena alternata, of the Trenton limestone, but it does not appear to be
subject to such extreme variations in respect to the striae. It also resembles
greatly in its surf ace- markings Strophodonta textilis, but it is always smaller,
has a more extended hinge-line, and is never so flat as that species. It is often
confounded with Strophodonta inequiradiata, which is a much larger species,
with different internal characters. Its surface striae are more delicate than any
of the other species.

Formation and Locality. — Occurs in the Corniferous limestone at the Palls of the Ohio, in Ken-
tucky and Indiana.

Strophodonta nacrea. HALL.

Strophodonta nacrea, Hall. Tenth Kep. on St. Cab., p. 144 — 1857
Strophomena lepida, Hall. Geol. Kep. of Iowa, Vol. 1, pt. 2, p. 493—1858.
Strophodonta nacrea, Hall. Pal. N. Y., Vol. 4, p. 104—1867.

Shell below medium size ; semi-elliptical, having a brilliant nacreous luster ;
hinge-line crenulated, equalling, or a little less, than the greatest width of shell
below ; cardinal extremities angular. Ventral valve regularly and moderately
convex ; depressed or slightly concave within the cardinal angles, caused by a
slight deflection of the cardinal extremities ; umbo depressed and the beak
very small, scarcely elevated above the hinge-line, and not incurved ; cardinal
area very small and without foramen.

Dorsal valve concave, corresponding in its depression with the form of tbe

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 147

ventral convexity ; its hinge-area is very narrow, almost linear ; no beak per-
ceptible.

Surface smooth, with a few concentric lines of growth. Prof. Hall states,
that in well preserved specimens, traces of very fine concentric, as well as radi-
ating striae have been observed. Our shells of this species are all entirely
silicified, in which condition the finer surface-markings are usually obliter-
ated.

Formation and Locality.— Found in the Corniferous limestone at the Falls of the Ohio, on the
Indiana shore of the river.

Strophodonta perplana. COXRAD.

Plate XVIII., figure 17.

Strophomena perplana, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. 8 — 1842.
Strophomena pluristriata, Conrad, ut. sup., p. 259.
Strophomena crenistria, Hall. Kep. 4th Geol. Dist. N. Y., p. 171—1843.
Strophomena (Strophodonta) fragilis, Hall. 10th Rep. on St. Cab., p. 143 — 1867.
Strophodonta fragiiis, Hall. Rep. Geol. Surv. of Iowa, p. 496 — 1858.

Shell semi-elliptical ; length varying from two-thirds to three-fourths the
width, which is from half an inch to two inches ; slightly concavo-convex, and
often nearly flat ; hinge-line equal, or often a little greater, than width of shell
below ; the cardinal extremities usually somewhat salient, except in extremely
old shells. Margins of the shell often a little concave just below the cardinal
extremities, making the width there less than below. From this incurvation
downwards, the lateral and basal margins form usually a regular curve.

Ventral valve very little convex, the greatest convexity above the middle of
its length, from where it slopes in a gentle curve to the lateral and basal mar-
gins ; towards the cardinal angles it slopes a little more rapidly, and as the
extremities are somewhat deflected, the valve becomes slightly concave between
them and the umbonal region ; the apex is scarcely rising above the hinge-line,
and slightly incurved.

Dorsal valve is gently concave, but often almost flat. Area of the ventral
valve is usually less than a line in width, and covered with vertical striae.
Area of the dorsal valve about half as wide as that of the ventral.

Surface covered by fine sub-equal striae, those of the ventral valve being
finer than the striae on the dorsal, extremely sharp, and often gently undu-
lating, increasing both by bifurcation and by intercalation, and crossed by fine,
even, concentric striae. Prof. Hall states, that in some specimens the longitu-
dinal atriae rise at frequent and regular intervals into minute granules, which
he Considers the bases of minute spines, formerly covering the ventral valve.
This feature is not indicated on any of our specimens as far as I know. The

148 PALAEONTOLOGY OF KENTUCKY.

dorsal valve is marked by fine, even, rounded striae, which are cancellated by
close concentric striae, and the same obscure concentric undulations, which are
often noticed on the ventral valve near the umbo. In general the shell is
readily recognized by its nearly flat form and by its fine, nearly equal striae.

Formation and Locality. — Occurs in the upper strata of the Devonian limestone at the Falls of
the Ohio, in Kentucky and Indiana, where the ventral valves are somewhat abundant.

Strophodonta profunda. HALL.

Plate XXIX., figure 26, and Plate XVII., figures 20 and 21.

Leptaena pr ofunda, Hall. Pal. N. Y., Vol. 2, p. 61, pi. 21, figures 4 and 5—1852.
Strophodonta profunda, Hall. 20th Regent's Kep., p. 369—1867.
Strophodonta profunda, Hall. 28th Regent's Rep., p. 151 — 1879.
Strophodonta profunda, Hall, llth Geol. Rep. of Ind., p. 289 — 1881.

Shell large, broadly semi-oval ; width larger than length ; hinge-line greater
than greatest width of shell ; cardinal extremities slightly extended and sub-
auriculate, in casts of ten obtuse or rounded; shell concavo-convex. Ventral
valve, according to Prof. Hall's description, very convex ; this is not the case
with our shells. In our specimens the ventral valve is only moderately convex ;
in some individuals the central portion around the umbo is most convex, while
the balance is depressed, or even somewhat concave ; in other shells the central
portion is flat, or even somewhat concave, while the marginal portion of the
valve all around, from one extremity to the other, is strongly curved ; and,
again, in some specimens the whole valve, with the exception of the cardinal
angles, is regularly and prominently curved ; in these shells, the cardinal ex-
tremities are slightly deflected, and the surface between them and the umbo
gently depressed or concave.

Hinge area narrow ; foramen triangular, of moderate size, and covered by a
strong deltidial callosity.

Dorsal valve corresponding in its concavity with the convexity of the ventral
valve. Hinge-area narrower than that of the ventral valve ; foramen covered
by a callosity. Surface marked- by strong, large, radiating striae, which alter-
nate with four or five smaller striae, all of which, the smaller as well as the
larger, increase by intercalation. These radii are crossed by fine concentric
lines. In some specimens the smaller striae become stronger, forming the
larger and less regular striae. The specimen illustrated on plate 17, figure 20,
is one of the largest found near our city.

Formation and Locality. — Occurs, in the Niagara rocks in the quarries east of the city of Louis-
ville. It is not abundant.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 149

Strophodonta plicata. HALL.

Strophodonta plicata, Hall. 13th Kep. on St. Cab., p. 90 — 1860.

Strophodonta plicata, Hall. Pal. N. Y., Vol. 4, p, 114, pi. 63, figs. 30-32—1867.

Shell of medium size ; semi-oval or semi-elliptical ; concavo convex ; hinge-
line somewhat shorter than the greatest width of shell ; cardinal extremities
rounded ; lateral margins almost straight or slightly curved ; basal margin
broadly curved. Shell resembling closely, as far as form is concerned, speci-
mens of Strophodonta demissa, of medium size and medium convexity.

Ventral valve moderately convex, with greatest convexity at about the mid-
dle of the shell, from where it slopes gently to the cardinal and lateral margins,
and somewhat more rapidly to the front. The umbo is small ; beak little
elevated and incurved ; cardinal area small, with a triangular fissure, closed by
the beak of opposite valve.

Dorsal valve moderately concave, nearly following the contour of ventral
valve ; its cardinal area very narrow, almost linear ; its beak closing the ventral
foramen.

The surface is ornamented by strong, sub-angular or rounded radiating
striae, which increase in number by bifurcation and intercalation, and which
are crossed by a few concentric lines of growth near the margin. This shell
resembles, as before stated, Stroph. demissa, from which it is, however, easily
distinguished by its strong and prominent striae ; there is about the same pro-
portion in strength between the striae of St. plicata and Stroph. demissa, as
between the striae of Atrypa aspera and Atr. reticularis.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation at and
around the Falls of the Ohio, in Kentucky and Indiana, where it is, however, a very rare shell.

Strophodonta striata. HALL.

Strophomena striata, Hall. Geol. Kep. of 4th Dist. N. Y.— 1843.
Leptaena striata, Hall. Pal. N. Y., Vol. 2, p. 259—1852.
Strophodonta striata, Hall. 28th Kegent's Rep., p. 152—1879.
Strophodonta striata, Hall, llth Geol. Report of Ind., p. 290—1881.

Shell semi-elliptical ; hinge-line equal or a little longer than the greatest
width of the shell below ; dorsal valve slightly convex ; ventral valve flat or
somewhat concave. Surface covered by unequal, radiating striae, of which
the stronger ones have large interspaces, which are occupied by one, mostly
by two, finer radii, all of which increase in number by intercalation, and not
by bifurcation. There are, sometimes, fine concentric lines of growth crossing
the radii, but these are often obsolete. The specimens of this species found
in our rocks differ somewhat in form from those found at Waldron, Indiana.

150 PALAEONTOLOGY OF KENTUCKY.

Our shells are more transverse, and show a somewhat geniculated base like
Slrophodonta rhomboidalis, and besides, are considerably smaller ; but these
differences are only the results of local conditions.

Formation and Locality. — Found in the Niagara limestone in the quarries east of the city of
Louisville, Ky.

Genus Strophomena.

Strophomena, Rannesque. Manuel de Malac. of Blainville — 1825.
Etymology: strophos, bent; mene, a crescent.

The Genus Strophomena was established by Rannesque, and has for its type
the S. rugosa, which is identical with Strophomena rhomboidalis of Wahlen-
berg, a species which ranges from the Lower Silurian to the base of the Car-
boniferous system. This species has some little differences in shape and mark-
ings, according to the formations in which it appears. I have not been able
to see Rannesque' s original description ; but whatever this may be, it covers all
the shells which are now included in this genus and those of Hall's genus,
Strophodonta, which latter will certainly be discontinued.

Strophomena rhomboidalis. WAHLENBEKG.

Plate XVIII., figures 1, 2 and 3.

Strophomena rhomboidalis, Wahlenberg. Acta. Soc. S. Upsaliensis, Vol. 8 — 1821.
Strophomena rhomboidalis, Hall. Pal. N. Y., Vol. 4, p. 76—1867.
See list of synonyms in last named report.

Shell of more than medium size ; semi-elliptical or sub-quadrate ; varying
greatly in its proportions of length and breadth; hinge-line straight, and
equal to greatest width of shell ; cardinal extremities mostly rectangular,
sometimes salient. The valves are geniculated, and the proportions of the
flattened part of the disc and the recurved part of the shell are very variable,
insomuch that the geniculation is sometimes little more than one of the strong
concentric wrinkles. (Hall.)

In the specimens of this species, found in our rocks, there is not so much
variation as stated in the foregoing description of Prof. Hall. Our shells
have almost all the form, as shown in the illustrations. They are sub-quadrate;
their lateral margins are parallel and almost straight, and the basal margin is
broadly curved. The geniculation is usually found in both valves, although
in some specimens the dorsal valve does not possess any, but is entirely plane.
The deflected portion of the lateral margins is triangular, with its apex at the
cardinal extremity ; it increases gradually towards the base, where it equals

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 151

in width the deflected basal margin ; the height of this basal deflection meas-
ures from one- third to one-half of the length of disc.

The ventral valve is slightly convex at and around the umbo, but flat or even
somewhat depressed between the umbo and the geniculation ; its beak is small
and only slightly curved.

Dorsal valve generally corresponding in its concavity with the convexity of
the ventral, only differing in the depth of the valve ; but in some shells there
is an exception to this rule, inasmuch as the dorsal valve is entirely straight
from the cardinal line to the level of the lateral and basal geniculation.

The surface is ornamented on the flattened portions of the shell by con-
centric, undulating, strong elevations, which are parallel with the curve of
the geniculation, and deflect outwards at the cardinal margin ; they are most
prominent in the portion parallel with the base, decrease in strength in their
lateral course, and become almost obsolete in some shells near the hinge-line ;
their number is variable, according to size and shape of the shell. The entire
surface is covered by radiating thread-like striae. The triangular fissure of tbe
ventral valve is partially closed by a deltidium and the apex of the ventral
valve.

Formation and Locality. — Occurs in the upper strata of the Devonian rocks in Jefferson county,
Ky., and in Clark county, Indiana. It is met with very often, but seldom found in fair, undistorted speci-
mens. The individual illustrated is one of the largest found here, though there is little difference in the
size of our shells belonging to this species

Strophomena rhomboidalis. WAHLENBERG.

This species has been described from the Devonian formation, in which the
conditions for the development of the shell appear to have been more favora-
able, inasmuch as the animal attained a considerably larger size. Outside of
this difference we find no distinction between the shells from both formations,
and there are no reasons for a new description here.

Formation and Locality. — Occurs in the Niagara limestone in the quarries east of the city of Louis-
ville, where it is, however, rare, and where it attains not even half the size of those found in the Devonian
rocks ia Clark county, Indiana.

Genus Leptocoelia. Han.

Leptocoelia, Hall. Rep. on the St. Cab. of Nat. Hist.— 1856.

Copied from Hall's Pal. N. Y., Vol. 3, page 447—1859.

Etymology: leptos, minute; koilia, belly, in allusion to the shallow visceral cavity.

Shell inequivalve ; variable in form, usually semi-oval or sub-circular,
transverse or elongate, plano-convex or concavo-convex ; hinge-line sometimes

152 PALAEONTOLOGY OB1 KENTUCKY.

equal to greatest width of shell. Ventral valve convex or sub angular in the
middle, with beak more or less extended ; moderately incurved. Foramen
terminal, the lower side formed by two deltidial pieces.

Dorsal valve flat or concave or depressed convex. A mesial fold and sinus
existing, but not often prominent. Structure of the shell lamellose or fibrous,
not punctate. Valves articulating by means of two strong teeth in the ventral,
inserted into the sockets in the dorsal valve, which are mainly excavated in
the base of a strong cardinal process. Teeth converging. Muscular impres-
sion marking a large ovate or flabelliform area, with a thin medium septum.
Adductor imprints small.

Leptocoelia hemispherica.

Plate XXXII., figures 21, 22 and 23, and 36 to 39.
Atrypa hemispheric^ Sovverby. Sil. Syst., p, 639 — 1839.
Atrypa hemispherica, Hall. Pal. N. Y., Vol. 2, p. 74—1852.
Atrypa hemispherica, Nicholson. Pal. of Ontario, p. 47 — 1875.

Shell rather small ; hemispheric or sub-circular ; plicated. Hinge-line in
some specimens extended and straight ; in others short and deflected towards
the front. Both valves in the specimens before me somewhat convex. Surface
ornamented by about ten to twelve strong, rounded, simple radii, which in-
crease in strength and in size of their interspaces from apex to front. The
two shells illustrated, sub-figures 21 to 23, and sub-figures 36 to 39, agree in
every feature except in the size and direction of their cardinal lines.

Formation and Locality. — Found in the lower strata of the Niagara group, which may possibly
belong to the Clinton, in the quarries east of the city of Louisville, Ky., where it is, however, a rather rare
species, of which fair specimens are very seldom foumi.

Genus Centronella.

Centronella, Billings. Can. Nat. and Geol., Vol. 4—1859.
Etymology : a little point.

Shells having the general form of Terebratula. Dorsal valve with a loop con-
sisting of two riband-like lamellae, which extend about one-half the length of
the shell. These lamellae at first curve gently outwards, and thence approach
each other gradually, until at their lower extremities they meet at an acute
angle ; then becoming united, they are deflected backwards towards the beak,
in what appears to be a thin, flat, vertical plate. Near their origin, each bears
upon the ventral side a single triangular crural process. This genus appears to
stand between Terebratula and Waldheimia. In the former the loop is short,
not exceeding greatly one-third the length of the shell, and not reflected. In
the latter it extends nearly to the front, and is reflected, but the laminae are
not united until they are folded back, (Billings.)

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 153

Centronella glans-fagea, HALL.

Plate XXXI., figures 14, 15, 16 and 17.

Rhynchonella glans-fagea, Hall. Tenth Rep. on St. Cab., p. 125 — 1857.
Cenironella glans-fagea, Billings. Canadian Nat. and Geol., p. 131 — 1859.
Centronella glans-fagea, Hall. Sixteenth Rep. on St. Cab. — 1863.
Centronella glans-fagea, Hall. Pal. H. Y., Vol. 4, p. 399 — 1867.

Shell small, ovate or sub-triangular, concavo-convex, with rounded base and
very unequal valves.

Ventral valve much larger than dorsal, greatly elevated in its center line
from beak to front, thus making the valve sub-carinate, or its transverse section
triangular. From the sub-carinate middle line it curves very abruptly to the
lateral margins, while longitudinally there is almost no curvature in the whole
valve except at the umbo; the beak is much extended beyond that of the
opposite valve, and arched dorsally far enough to extend to the level of dorsal
valve.

Dorsal valve sub-angularly concave from beak to front, the depression cor-
responding to the angular elevation of the other valve ; the beak not incurving
into the opposite valve ; the mesial sinus widening rapidly towards the front,
extending in the basal third to the lateral margins. With the exception of
some concentric lines of growth, there are no other surface-markings. The
specimen illustrated is one of the largest found in Kentucky; it also shows the
usual proportion between width and length. Comparing our shells of this
species with Prof. Hall's figures, we find them differ from most of his forms in
size and shape ; still they have the specific aspect and characters.

Formation and Locality. — Found in the rotten hornstone of the Devonian group in Jefferson
county, Ky., and Clark couiity, Indiana, where it is, however, rarely met with, especially in well preserved
or even fair specimens.

Genus Terebratula. Lihwya.

Terebratula, Llhwyd. Lith. Brit. Ichn. — 1696.
Etymology : diminutive of terebratus, perforated.

Types : T. maxillata and T. vitrea.

Shell minutely punctate, smooth and convex, usually round or oval. Ven-
tral valve with a prominent beak, which is truncated and perforated ; foramen
circular.

Dorsal valve with a depressed umbo ; a prominent cardinal process between
the dental sockets ; deltidium of two pieces, frequently blended ; loop very
short, simple, attached by its crura to the hinge-plate,

GEOL. SUK. — 20

154 PALEONTOLOGY OF KENTUCKY.

Terebratula harmonia. HALL.

Plate XVII., figures 1, 2, 3 and 4.
Terebratula harmonia, Hall. Pal. H. Y., Vol. 4, p. 388—1867.

Shell of more than medium size ; ovate or sub-spatulate ; tapering somewhat
abruptly to the beak, compressed at the margins, but convex in middle ; base
regularly curved.

Ventral valve regularly arcuate from beak to front, moderately convex in
the middle ; a little gibbous above, and depressed convex or slightly concave
towards the front ; the upper part narrowing ; the beak much extended, atten-
uate and arcuate, but not closely incurved ; apex perforated, the slope to the
cardinal margin scarcely concave ; deltidial plates large.

Dorsal valve moderately convex, sometimes a little more prominent along
the middle in the upper part, and depressed towards the front and sides.

Surface marked by fine concentric lines of growth ; the substance of the
shell finely punctate.

This species resembles to a certain degree Ter. sullivanti, but it is. more regu-
larly arcuate from beak to front of the ventral valve, and has a regularly
rounded base, while Ter. sullivanti has a truncate or sinuate front. Its well
marked regular form in larger specimens will easily identify it.

Formation and Locality.— Found in the corniferous limestone at and around the Falls of the Ohio,
in Kentucky and Indiana. It is a somewhat rare species. Prof. Hall received the original specimens,
from which he made his description and illustrations of this species, from the late Dr. James Kiiapp, who
collected the same at the Falls of the Ohio.

Terebratula jucunda. HALL.

Terebratula jucunda, Hall. Pal. N. Y., Vol. 4, p. 390—1867.

Shell of medium size ; sub-circular or very broadly ovate ; length and width
about equal ; regularly rounded in the margins of the basal half, but abruptly
converging to the ventral apex in upper half.

Ventral valve moderately convex ; gibbous in the umbonal region, sloping
in a gentle, regular curve to the base and baso-lateral margins, showing a faint
mesial depression ; beak obtuse and arched over the umbo of the opposite
valve ; apex truncated by a rounded foramen.

Dorsal valve less convex than the ventral, but regularly arched all over the
surface, with the exception of the cardinal angles, which are somewhat in-
flated. The specimen before me shows a faint elevation in the basal half,
corresponding with the sinus of opposite valve.

Surface is marked by fine concentric striae or lines of growth. My specimen
measures in length and width a little more than three-eighths of an inch.

Formation and Locality. — Occurs in the corniferous limestone in Jefferson county, Kentucky, and
in Clark county, Indiana,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 155

Terebratula lincklaeni. HALL.

Plate XVII., figures 22, 23 and 24.

Terebratula lincklaeni, Hall. 13th Regent's Report — 1860.
Terebratula lincklaeni, var., Hall. Pal. N. Y., Vol. 4, p. 418—1867.

Shell of medium size; sub-ovate or sub triangular, with broadly curved or
slightly truncated base ; moderately ventricose; length somewhat exceeding
width.

Ventral valve larger, and slightly more ventricose than the dorsal ; greatest
convexity at the unibo, from where it slopes in a gentle regular curve to the
lateral and basal margins, but abruptly towards the cardinal margins, whose
borders are somewhat inflected ; the umbo is prominent, and the beak elevated
and incurved above the beak of the other valve ; at the front there is a slight
depression noticeable, but this feature is often wanting.

Dorsal valve smaller, and less convex than the ventral ; greatest convexity
at the umbo, from where it slopes in an almost straight, line to the front, in a
gentle curve to the lateral margins and abruptly to the cardinal lines ; umbo
moderaetly prominent, and the beak strongly incurved under that of the
opposite valve.

The surface is covered with concentric lines of growth, some of which are
more prominent, and divide the surface of some individuals into different
zones. No other surface-markings are visible on our specimens, which are all
in a silicified condition.

Formation and Locality. — Found in the rotten hornstone of the Devonian formation, in Jefferson
county, -Ky., and in Clark county, Ind.; it is of rather rare occurrence. This species resembles Ter.roemin-
geri, with which it is associated, but differs by having its greatest width near the base, while Ter.roemin-
geri has its maximum width above the middle, and the latter species is generally more gibbous and stronger
umbonated.

Terebratula roemingeri. HALL.

Plate XVI., figures 20, 21 and 22.

Terebratula roemingeri, Hall. Sixteenth Rep. on St. Cab., p. 48 — 1863.
Terebratula roermngeri, Hall. Pal. N. Y., Vol. 4, p. 389—1867.

Shell ovate, more or less gibbous ; truncate or slightly sinuate in front.

Ventral valve gibbous above the middle; umbo gibbous, inflated; beak promi-
nent, incurved over that of the opposite valve, and truncated by a round for-
amen, which is often mainly anterior to the apex, and completed on the lower
side by two deltidial plates ; cardinal slopes rounded, often depressed in the
middle towards the front.

Dorsal valve extremely gibbous, little longer than wide ; the greatest con-
vexity at the middle or above.

Io6 PALEONTOLOGY OF KENTUCKY.

Surface marked by fine concentric lines of growth, which are often crowded
into prominent wrinkles towards the front. Shell structure finely punctate.

The interior shows a short terebratuliform loop, which is abruptly recurved
at its lower extremities.

This species resembles Ter. lincklaeni, from which it differs, however, by its
greater gibbosity, by having its greatest width above the middle, while that
species has its maximum width near the base, and by its truncated or sinuate
base.

Formation and Locality. — Pound in the rotten hornstone of the Devonian formation in Jefferson
county, Ky., and in Clark county, lud, A rather rare species.

MOLLUSCA.

PTEROPODA.
Genus Tentaculites.

^ Tentaculites, Schiotheim. Petrefacten— 1820.
Etymology : tentaculum, a feeler ; lithos, stone. ]

The shells belonging to this genus are easily distinguished by their exterior
appearance ; they form very elongated, slender cones, marked by prominent
annulations and fine transverse striae.

The place which these shells had to occupy in the great sub-kingdom Mol-
lusca, was for a long time doubtful, until in 1845 Mr. Austin assigned them to
the Pteropoda, which position is accepted by all the naturalists up to the pres-
ent day, though doubts are sometimes expressed as to their relation with the
thin hyaline shells of most of the existing forms of Pteropoda.

Tentaculites scalariformis. HALL.

Plate XXXI., figure 12.

Tentaculites scalaris, Hall. Geol. of N. Y., 4th Dist., p. 172—1843.
Tent, scalariformia and T. stcula. Hall. Illust. of Dev. Fossils — 1876.
Tentaculites scalariformis, Hall. Pal. N. Y., Vol. 6, pt. 2, p. 167—1885.

Shell elongate-conical, straight, somewhat more cylindrical in approaching
the aperture ; the apex in well preserved specimens extremely attenuate, and
quite solid for one-fourth to one-third of the entire length of the shell. Annu-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 157

lations prominent, sub-angular, sometimes rounded on the larger part of the
<-one ; closely arranged and sharply angular near the apex, gradually increas-
ing their distance; becoming less angular with the increase of the size of the
skell and obtuse and rounded towards the aperture. On the outer half of
th* shell, tht- spaces between the annulations are greater than the annulations
themselves. The interspaces, as well as the annulations, are covered in well
preserved specimens with fine, even, transverse striae; the number of which
differ greatly. In some specimens there is much irregularity in the distance
and development of the annulations towards the aperture. The extreme
point of the apex is rarely or never preserved in our specimens.

Our specimens of this species are always silicitied, and maintain their origi-
nal cylindrical form ; they never suffered compression.

The shells of this species attain a length of one inch — rarely more, but
usually somewhat less. The largest individual before me, and of which the
illustration — figure 12, plate 31 — was made, measures one-half of an inch ; the
figure is enlarged to double size.

Formation and Locality. — Found in the rotten hornstone of the Devonian formation, in Clark
county, Indiana, on the northern shore of the Ohio river, opposite its falls, and in the cherty layers super-
imposed upon the hydraulic limestone at Watson's Station, on the Ohio and Mississippi Railroad

Genus Styliola Lesueur.

Etymology : stylos, a pillar.

Prof. Ludwig gives the following translation of a description of this genus
from M. Barrande : Shell small ; transverse section circular ; closed below,
and thicker than in the upper part ; conical. Surface without annulations ;
smooth, but with fine striae of growth, and sometimes with fine longitudinal
striae ; without longitudinal slit, but sometimes with one or two longitudinal
grooves, which do not penetrate the shell ; without operculum, and without
interior partitions, but having a persistent point sometimes curved backward.
The greatest width is at the opening, which is oblique or normal to the axis
of shell.

Styliola fissurella. HALL.

Tentaculites fissurella. Hall. Geol. Surv 4th Dist. N. Y.— 1843.
Not. Tentaculites fissurella, Hall. 111. of Dev. Fossils— 1876.
Styhola fissurella, Hall. Pal. N. Y., Vol. 6, pt. 2, p. 178—1885.

Shell an extremely slender, elongate cone. Apical portion of shell solid.
Apex extremely minute, often bulbiform, and very gradually enlarging to the
aperture.

Surface often smooth and without any visible ornamentation, so far as can

158 PALEONTOLOGY OF KENTUCKY.

be ascertained, or with fine striae or lines of growth, which are often unequally
developed on different parts of the shell ; and also with fine longitudinal
striae, which may be present with or without the transverse striae. Length
different in different individuals. Prof. Hall gives their length from two to
five millimeters.

The specimens before me, which have all the characters mentioned in the
foregoing description, are considerably larger ; they are only fragments, with-
out apex and aperture, but all indications point at least to a length exceeding
half an inch.

Formation and Locality. — Occurs in the upper strata of the Devonian formation, at and around
the Fulls of the Ohio, in Kentucky and Indiana. This little shell is rather rare.

MOLLUSCA.

GASTEROPODA.
Genus Bellerophon.

Bellerophon, Montfort. Conch. Syst., Vol. 1—1808.
Etymology : a mythological name.

The type of this genus is Bellerophon bicarinatus. The shells of this genus
are symmetrically convoluted, globular or discoidal, strong, few whorled ; the
whorls are often sculptured ; dorsally keeled. The apereture is sinuated and
deeply notched on the dorsal side ; its shape is variable, sometimes triangular,
and sometimes reniform or sub-orbicular. The surface is usually marked by
fine concentric striae, and sometimes by fine revolving striae also.

This genus extends from the Lower Silurian to the Carboniferous, inclu-
sively.

Bellerophon leda. HALL

Plate XVII., figures 12 and 13.

Bellerophon leda, Hall. Descpt. of New Sp. of Foss., p. 30—1861.
Bellerophon leda, Hall. Fifteenth Rep. N Y St. Cab., p. 58—1862.
Bellerophon leda, H. and W. 29th Regent's Rep., p. '200—1872.
Bellerophon leda, H and W. 27th Regent's Rep., pi. 13—1875.
Bellerophon leda'QM. Illust of Dev. Foss., pi 24— 1876.
Bellerophon leda, Hall. Pal. N. Y , Vol 5, pt. 2 p. 110—1879.

Shell sub-globose, often a little flattened upon the dorstim ; body-whoil
ventricose, very rapidly expanding ; aperture very wide ; peristome abruptly

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 159

spreading, broadly sinuate in front, and sometimes with a deep notch in the
middle. The margin gently recurved, joining the volution a little on the
ventral side where it is thickened, somewhat abruptly curving over and partly
inclosing the small umbilicus, and extending in a callus over the columellar
lip, which is sometimes distinctly striato-pustulose.

Surface marked by strong longitudinal or revolving striae, which alternate
in size ; are sometimes fasciculate, and often finer and more numerous on each
side of the dorsal band than on the lateral portions of the shell. The revolv
ing striae are cancellated by finer, sub-equal, thread-like, transverse striae.
The dorsal band is narrow, rarely elevated, or sometimes scarcely raised above
the surface, and usually flat or slightly concave ; the concentric striae making
an abrupt retrorse curve upon it in crossing. The band is likewise usually
marked by two, three or more revolving striae, finer than those on the sides of
the shell, and sometimes quite obscure.

This species is very variable in size and form as well as in surface-markings,
which are, however, mainly due to the distortion of the shell. A specimen
without distortion is a very rare occurrence. The average size of this shell is
about three-fourths of an inch. The specimens found in our rocks seldom
exceed the one illustrated on our plate.

Formation and Locality. — Occurs in the rotten hornstone of the upper strata of the Devonian for-
mation, in Jefferson county, Ky , and in Clark county, Ind., where it is not rare, but fair specimens are
seldom found.

Genus Bucania. Han.

Bucania, Hall Pal N. Y., Vol. 1-4847.
Etymology . bukane, a trumpet.

Shells convolute ; spire equally concave on either side ; volutions in the same
plane, all visible, outer one ventricose, inner ones usually angulated on the
edge, concave on the ventral side ; aperture rounded oval, somewhat com-
pressed on the inner side by contact with the next volution, laterally and dor-
sally abruptly expanded.

This genus is established for the reception of several species of shells of a
peculiar form, which were formerly placed with the Bellerophons, but from
which they differ by having all their volutions visible, which is not the case in
Bellerophon proper. Bucania differs from Porcella in being symmetrical, the
volutions in the same axis being equally expanded on either side, both sides
presenting the same aspect, and the aperture corresponding to the axis of the
shell.

160 PALAEONTOLOGY OF KENTUCKY.

Bucania devonica. HALL AND WHITFIELD.

Plate XXVI., figure 9, and Plate XXII., figures 3 and 4.
Bucania devonica, H. and W. 24th Regent's Kep., p. 195 — 1872.
Bucania devonica, H. and W. 27th Kegent's Rep., pi. 13 — 1875.

Shell discoid, widely and equally umbilicate on the two sides ; remaining
volutions about four ; slightly embracing, vertically compressed, giving the
transverse diameter a little more than twice the vertical diameter. Lateral
margins of the volutions obtusely angular towards the dorsal side.

The surface has apparently been marked by several (three or four) revolving
ridges or carina on each side of the center or dorsum, which is greatly concave.
Finer surf ace- markings, and also the form and size of tjie aperture, are un-
known.

Formation and Locality. — Occurs in the Corniferous rock of the Devonian formation in Jefferson
county, Ky., and in Clark county, Ind. It is always found in an exfoliated condition as internal casts,
which seldom show any surface-markings at all,

Genus Platyceras. conrad,

Plaiyceras, Conrad. Ann. Geol. Rep. of N. Y. — 1840.

Etymology ; platys, broad ; keras, a horn.

Copied from Hall's Pal. N. Y,, Vol. 3, page 309—1859.

Shell depressed sub-globose, sub ovoid or obliquely sub-conical. Spire small,
volutions few, sometimes free and sometimes contiguous, without columella.
Aperture more or less expanded, often companulate, and sometimes with the
lip reflected. Peristome entire or sinuous.

Surface striated or cancellated, often spirally ridged or plicated, and some-
times strongly lamellose transversely, nodose or spiniferous.

Platyceras bucculentum. HALL.

Plate XXIII., figures 9 and 11, and Plate XXV,, figure 8.
Platyceras bucculentum. Hall. Desc, of New Sp of Foss , p. 6 — 1861.
Platyceras bucculentum, Hall 15th Regent's Rep, p. 33 — 1862.
Platyceras bucculentum, Hall, lllust of Dev. Fossils, pi. 3 — 1876. v

Platyceras bucculentum, Hall. Pal. N. Y., Vol. 6, pt. 2, p. 10—1885.

Shell ventricose, obliquely sub-ovoid ; apex extremely attenuate, the spire
making one or two closely enrolled volutions, with a gently enlarging diameter,
and below this abruptly expanding; very ventricose in the middle and lower
part, spreading more upon the right side than upon the left. The shell near
the posterior side swells out into a distinct pouch-like projection, with two or
three rounded folds or semi-plications, which give a deeply sinuous outline to
the margin. Aperture sub- ovate and sinuate on the right posterior side. Per-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 161

istome sinuous, and on the posterior side spreading partially over the preceding
volution.

Surface marked by fine, closely arranged concentric striae, which are undu-
lated towards the margin of the aperture, and sometimes over the greater part
of the surface, the irregularity having commenced during the earlier stage of
growth. In well preserved specimens there are revolving striae or fascicles,
rising in little bands of obsolescent striae, giving a waved aspect to the sur-
face.

This species resembles somewhat P. ventricosum, of the lower Helderberg
group, but the first volution is more slender, the spire less closely enrolled,
while the pouch-like expansion and the revolving bands are distinctive fea-
tures. In size it differs greatly in different specimens, as may be noticed in the
different figures.

Formation and Locality — Occurs in the Corniferous limestone of the Devonian formation in
Jefferson county, J£y,, and in Clark county, Ind.

Platyceras conicum. HALL.

Plate XXV., figures 2 and 11. •

Platyceras conicum, Hall. Descript. of New Foss., p. 3 — 1861.
Platyceras conicum, Hall. 15th Keg. Report, p. 31 — 1862.
Platyceraa conicum, Hall. Illust. Devon. Fossils — 1876.
Platyceras conicum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 3—1885.

Shell above medium size, erect conical, the minute apex closely incurved
but mostly missing, at least in the specimens found in our rocks. Body-
chamber entirely straight, with broad, undefined, longitudinal ridges and
depressions, which are faint or obsolete at or near the apex, but become more
distinct approaching the aperture. The height of the shell is usually greater
than the width of the aperture, which is somewhat elliptical in shape ; its
length exceeding its width.

The surface is covered by concentric undulating striae, which become sub-
lamellose towards the aperture, and are sometimes closely crowded and
wrinkled with numerous knots or nodes. Peristome deeply sinuous. The
length of the shell varies in different specimens, and can not be exactly as-
certained on account of the missing apex; but it is certain that the shell
illustrated in figure 11, plate 25, if complete, would certainly measure not less
than two inches and a quarter.

This species resembles P. pyramidatum of the Lower Helderberg group, but
is less elongate ; the peristome more sinuous, and the longitudinal ridges and
depressions are more distinct; besides, the crowded, wrinkled and nodose striae
of our shell are missing in the Silurian species.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation at the
Falls of the Ohio, on the Kentucky side of the river, and in different other places in Jefferson county, Ky.,
and Clark county, Ind. It is not very rare, but fair specimens are not abundant.
OEOL. SUR. — 21

162 PALAEONTOLOGY OF KENTUCKY.

Platyceras compressum. N. SP.

Plate XXV., figures 8 and 9.

Shell of medium size or below it ; very compressed in a lateral direction.
Apex closely enrolled for one or one and a half volutions, which increase in
size very gently ; after this the body-whorl, measuring a little more than a half
volution, expands very rapidly in the post anterior direction, while its lateral
extension remains almost the same throughout the whole length of the body
volution. The right side of the shell is moderately convex in the apical half,
but becomes concave in the lower half, the center line of the concavity running
at right-angles to the peristome. The left side is throughout concave, but the
center line of the concavity is parallel to the peristome, or at least nearly so.
The aperture is very elongate and narrow, and expands more or less at the
posterior end of its right side. The surface is marked by fine concentric lamel-
lose striae, which are closely arranged, especially in the lower half, and by
somewhat obscure, shallow, radiating plications, only noticed in the lower
part.

A smaller specimen, of about half the size of the one illustrated, does not
show any indications of those plications. The size of the larger specimen is
shown in figures 8 and 9, on plate 25.

Formation and Locality. — This beautiful little shell was loaned to me for description and illustra-
tion by Major Wm. J. Davis, who found it at the Falls of the Ohio, in the Corniferous limestone, imbedded
in the rock, which he removed, without the least injury to the shell, by the use of muriatic acid and para-
fine. The smaller specimen he found in the same strata, but already weathered out, in Clark county
Indiana.

Platyceras dumosum. CONRAD.

Plate XXIII., figures 1 to 6 and 12.

Platyceras dumosum, Conrad. Third Ann. Kep. of 4th Dist. N. Y. — 1840.
Platyceras dumosum, Hall. 12th Kegent's Report, p. 19 — 1859.
Platyceras dumosum, Hall. Descript. of New Spec, of Fossils — 1861.
Platyceras dumosum, Hall. 15th Regent's Report, page 37 — 1862.
Platyceras dumosum, Hall. Illust. of Dev. Foss., pis. 5 and 6 — 1876.
Platyceras dumosum, Hall. Pal. N. Y., Vol. 6, pt. 2, page 14—1885.

Shell above medium size ; sub-ovoid ; extremely ventricose in full grown
specimens. Its length, from the apex to the anterior margin of the aperture,
greater than the height. Apex minute, closely enrolled for a single volution
or more, then the body-whorl becomes free and rapidly expanded, spreading
more upon the right side, which is sometimes depressed-convex, while the left
side is more abruptly rounded. The aperture is sub-rhomboid-ovate, with
the peristome making a sinus on the left side, the posterior margin widely
separated from the preceding volution.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 163

The surface is marked by strong concentric striae, which are interrupted and
irregular from the numerous nodes projecting from the shell, and extended
into long tubular spines.

This shell, in full grown specimens, attains sometimes a length of two inches
and a half, and its entire surface is covered with strong, tubular spines, which
are sometimes two inches long, as may be seen in the inclosing rock. In the
specimen figured on plate 23, figure 2, all the spines are preserved to a certain
extent ; some measure more than half an inch. These shells were found at the
falls, imbedded in soft limestone ; the shells themselves were entirely silicified.
By the use of muriatic acid, the limestone envelope was gradually removed,
and any portion of the shell or spines, whenever it was sufficiently freed from
the matrix, was then carefully coated with paraffine, to prevent the acid from
further acting upon these cleared portions. By this process, in which very
diluted acid must be used, and which requires often several days close watch-
ing, in order to protect the exposed parts in time from the further action of
the acid, the most excellent specimens in shells, crinoids, and especially in
coral, are obtained. In the collection of my co-laborer and friend, Major Wm.
J. Davis, the author of "Kentucky Fossil Corals," the most exquisite and
valuable specimens of which that cabinet is so rich, and, therefore, unparalleled
by any other collection in this country, are produced by the careful application
of muriatic acid and paraffine. The specimens of this species, found in the
clay, are mostly exfoliated, and show the places of the spines by moderately
elevated nodules, as may be seen in the figures 5, 6 and 12 ; the last one is that
of a young specimen.

Formation and Locality. — Occurs in the upper strata of the Corniferous limestone, just above the
hydraulic cement rock, at the Falls of the Ohio, on the Kentucky side of the river; the layers containing
them are only exposed at a very low stand of the river. In the clay, exfoliated shells are found in differ-
ent places in Jefferson county, Ky., and in Clark county, Ind.

Platyceras dumosum, var. rarispinum. HALL.

Plate XXIII., figures 7 and 8.

Platyc. dumosum, var. rarispinum. Hall. Desc. of New Sp. of Foss. — 1861.
Platyc. dumosum, var. rarispinum, Hall. 15th Reg. Rep., p. 38 — 1862.
Platyc. dumosum, var. rarispinum, Hall. Illust. of Dev. Foss., pi. 5 — 1876.
Plat, dumosum, var. rarispinum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 16 — 1885.

Shell only of medium size or below it ; sub-ovate ; apex closely incurved
and enrolled for about one and one-half volutions, and in some shells the volu-
tions are contiguous nearly to the aperture, as seen in figure 8, plate 23. For
one volution and a half or three-fourths the shell is slender and only gently
enlarging ; after that the body- whorl expands more rapidly and becomes mod-
erately ventricose, depressed on the dorsum, and the left side sometimes

164 PALEONTOLOGY OF KENTUCKY.

marked by a strong fold, indicating a sinus in the margin of the peristome
commencing at an early stage of growth. Aperture somewhat oval, longest
in the dorsal-ventral axis.

Surface marked by wrinkled, concentric striae, which are strongly undulated
at the base of the spines, and often abruptly bent backward at other places.
Spines scattered, comparatively strong and few in number, from five to fifteen
on the whole shell. The specimen before me, a most perfect one, with the
exception of a few broken spines, is a complete hollow shell from apex to
aperture, without defect ; it shows eleven spines.

Formation and Locality. — This shell was presented to me by Major Win. J. Davis, who found it
in the upper strata of the Devonian formation, in Clark county, Indiana. I have no doubt that this shell
is related to P. dumosum, but it differs sufficiently from it to constitute a distinct species,"and not merely
a variety. It is certainly as far removed from P. dumosum as P. multispinosum, and if that is considered
a good species, I think our shell has the same claim. It ought to be called simply Platyceras rarispinum.
It differs by the smaller number of spines, and by its different shape from P. dumosum, and besides, it is
never found with the latter in the same strata, but occupies a higher horizon.

Platyceras echinatum. HALL.

Plate XXXI., figure 21.

Platyceras echinatum, Hall. Descript. of Xew Foss. — 1861.
Platyceras echinatum, Hall. 15th Kep. N. Y. St. Cab.— 1862.
Platyceras echinatum, Hall. Illust. of Dev. Fossils — 1876.
Platyceras echinatum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 13—1885.

Shell small ; apex closely incurved for about one and one-half volution ; the
body-whorl occupying about one volution, very ventricose ; rapidly expanding
from the first volution, giving the shell an obliquely conical form. Aperture
nearly circular or broad oval ; peristome sinuate ; the lines of growth and fine
striae conforming in direction to the outline of the margin. Remains of
revolving lines are sometimes traceable when the shell is not exfoliated.
Besides the concentric and obscure revolving striae, the surface is studded
with numerous nodes or fine spines, which are as much crowded as the figure
21, plate 31, shows, but they are not quite so regularly arranged as in the
illustration. The specimen before me has preserved the shell, but of the
spines only short stumps are visible ; the spines perished by the process of
silicification. In regard to size, this species varies from half an inch to an
inch and a quarter in length, and in large specimens the greatest diameter
of the aperture is one inch. This form could be the young of P. dumosum,
and would probably be considered as such if it occurred with that species in the
same strata or horizon, but this is not the case. It is never found associated
with P. dumosum, but occurs at a much higher horizon, and for that reason
must be considered as a distinct species.

Formation and Locality. — Found in the upper strata of the Devonian formation, in Clark county,
Indiana. It is not often met with.

FOSSILS OF THE SILURIAN ANL> DEVONIAN ROCKS. 165

Platyceras erectum, HALL.

Acroculia erecta, Hall. Geol. Surv. of 4th Dist. of N. Y.— 1843.
Platyceras erectum, Hall. Desc. of New Sp. of Foss., p. 4 — 1861.
Platyceras erectum, Hall. 15th Regent's Report, p. 4 — 1862.
Platyceras erectum, Hall, lllust. of Devon. Fossils, pi. 2 — 1876.
Platyceras erectum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 5—1885.

Shell erect and slender. The spire at the apex is closely enrolled, for about
one volution and a half, beyond which the body-volution becomes somewhat
rapidly expanding, with the aperture often spreading. The specimens are
often more arcuate than their name indicates. The aperture is oblique, with
the peristome sinuate.

The surface is marked by closely arranged, revolving, lamellose striae, which,
upon the lower half of the body- volution, are abruptly arched along narrow
bands, corresponding with former sinuosities of the aperture.

Formation "and Locality. — Occurs in the Corniferous limestone of the Devonian formation, at the
Falls of the Ohio, on Kentucky shore of river.

Platyceras milleri. N. SP.

Plate XXV., figure 1.

Shell very elongate, forming a slender cone. Apex very minute, and closely
incurved for about one or one and a half volution; after this the shell is free
for about one and one-half volution. The whole shell increases very gradu-
ally in size from apex to aperture. The different volutions are separated
from each other by very large interspaces. The aperture is nearly circular,
and the lip is entire without sinus, but with very slight undulations. The real
shell is very thin. The surface is marked by fine, undulating concentric striae
or lines of growth, and, in well preserved specimens, with numerous slender,
tubular spines, which are seen when part of the matrix remains attached to
the shell. To a specimen of that kind before me are spines attached which
measure more than three-fourths of an inch in length.

This species resembles, in regard to the number and size of the spines,
Platyceras dumosum, but its elongated form distinguishes it from that species
at the first glance. There is, in fact, no other species of Platyceras known to
me with which this one might be compared.

Formation and Locality. — I found three very fine specimens of this species in the Corniferous
limestone of the Devonian formation, at the Falls of the Ohio, on the Kentucky side of the river.

It affords me great pleasure to name this elegant fossil In honor of S. A. Miller, Esq., of Cincinnati,
Ohio. There are very few palaeontologists in this country whose labors are of equal importance with those
o ' 8. A. Miller. His catalogue of fossils is an invaluable guide to all his co-laborers.

166 PALEONTOLOGY OF KENTUCKY

Platyceras multispinosum. MEEK.

Plate XXV., figure 4.

Platyceras multispinosum, Meek. Proc. Acad. Nat. Sci. Phil. — 1871.
Paiyceras multispinosum, Meek. Pal of Ohio, Vol. 1, page 210 — 1873.

Shell attaining a large size, considerably larger than its near relative, the P.
dumosum ; it has a very thin shell, is depressed sub-ovate and very oblique.
Its apex is free in the casts — may not be so in the perfect shell ; comparatively
stout, and obliquely coiled for about one and one-half volution ; after this the
body-whorl expands very rapidly to the aperture, occupying in this part of
the shell less than half a volution.

Aperture very large and nearly round ; lip entire ; neither sinus nor undu-
lated.

Surface without any surface-markings except the numerous closely arranged,
slender, tubular spines on well preserved shells, or their small, depressed,
smooth, undefined tubercles or nodules on the internal casts. In regard to
general size, and the proportion of its different dimensions, this shell differs
greatly. The illustration, figure 4, on plate 25, shows a large-sized specimen.
This species differs from Platyceras dumosum by its considerably larger size,
its more oblique, depressed and more rapidly expanding form, and mainly by
its more numerous and more slender spines. Specimens belonging to this
species will be very seldom confounded with P. dumosum ; their difference
is noticed at the first glance, whether they are shells or internal casts. The
spines are seldom attached to the specimens ; they become separated by exfoli-
ation, but are often preserved in the matrix.

Formation and Locality- — Occurs in the Corniferous limestone of the Devonian formation at the
Falls of the Ohio, and in other places in Jefferson county, Ky., and Clark county, Ind. It is not rare,
though fair specimens are not abundant.

Platyceras rictum. HALL.

Platyceras rictum, Hall. Desc. New Sp. of Poss , p. 7 — 1861.

Platyceras rictum, Hall. 15th Regent's Rep., p. 35 — 1862.

Platyceras rictum, Hall. Illust. of Dev. Fossils, pi. 4 — 1876.

Platyceras rictum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 13—1885.

Shell very depressed, arcuate or sometimes obliquely sub-conical; width
equalling and often exceeding height. Apex or nucleus minute, the spire
enrolled for about one turn and a half, when it abruptly expands, spreading
more upon the right posterior side, and becoming greatly extended and ex-
panded in front.

The dorsal line of the first volution is continued in an oblique angular ridge,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 167

extending on the left side, and often reaching to the front of the shell, giving
a peculiar obliquity to the form. Aperture expanded, obliquely ovate ; peris-
tome entire, or with a slight sinuosity on the left posterior side, and sometimes
showing the effect of the undefined folds of the posterior margin usually con-
tiguous to the preceding volution.

Surface marked by undulating concentric striae, and a few broad undulations
longitudinally. Aperture a little greater in the diameter from front to rear
than in the lateral one. Height reaching sometimes to an inch and a quarter.

Formation and Locality. — Occurs in the Coruiferous limestone of the Devonian formation in Jeffer-
son county, Ky., and in ClurU county, Ind.

Platyceras symmetricum. HALL.

Plate XXIII., figure 10.

Platyceras symmetricum, Hall. Desc. of New Sp. of Foss., p. 6—1861.
Platyceras symmetricum, Hall. 15th Eeg. Kep., p. 34 — 1862. t
Platyceras symmetricum, Hall. Illust. of Dev. Fossils, pi. 3 — 1876.
Platyceras symmetricum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 9—1885.

Shell elongate, sub-ovoid, arcuate, incurved nearly in the same plane ; apex
minute, making about one or one and a half volution before the body-whorl
becomes free and rapidly or somewhat abruptly expanded ; spreading about
equally on the two sides of the dorsum, which is more prominent and some-
times marked by a ridge. Aperture oblique, sub-quadrate or rhomboidal ;
margin of the peristome sinuate, and on the posterior side distant from the
spire.

Surface marked by concentric undulating striae, and longitudinally by
obscure interrupted ridges, which, on some parts of the older shells, become
regular and uniform, with a narrow groove between.

This species is well marked by the equilateral expansion on each side of the
dorsum, and by the volution of the apex being nearly in the same plane. The
posterior margin of the aperture is widely separated from the preceding volu-
tion. The longitudinal ridges are strongly marked, and of a different char-
acter from those of characteristic specimens of Plat, bucculentum ; it is not,
however, improbable that we may find intermediate forms uniting the two
species. It is also possible that a comparison of a larger number of specimens
may prove that the forms included under P. thetis, symmetricum and buccu-
lentum, are only varieties of one and the same species.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation at the
Falls of the Ohio, and in different other places of Jefferson county, Ky., and of Clark county, Ind., where
it is usually found already weathered put and entirely silicified.

168 PALAEONTOLOGY OF KENTUCKY.

Platyceras thetis. HALL.

Platyceras thetis, Hall. Desc. of New Foss., page 4—1861.

Platyceras thetis, Hall. 15th Kegent's Rep., p. 32—1862.

Platyceras thelis, Hall. Illust. of Dev. Foss., pi. 3—1876.

Platyceras thetis, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 8—1885.

Shell oblique arcuate from base, with the apex incurved, nucleus making
barely more than a single minute volution ; gradually expanding from the
apex to near aperture, which is sometimes more abruptly spreading. The
beak of the body- whorl is prominent, and a little flattened on the left side,
while right side, from one-third to one-half the length, is sometimes marked
by two or three longitudinal folds, and often by more numerous, finer plica-
tions. Aperture a little oblique, nearly round or sub-quadrate, with the peris-
tome sinuous.

Surface marked by line, closely arranged lamellose striae, which are abruptly
undulated on all parts of the body of the shell. This species resembles P.
attenuatum, but differs in being arcuate from apex to base, in the gradual
attenuation towards the apex , and the closely incurved nucleus and less abrupt
expansion.

Formation and Locality. — Occurs iii the Comiferous limestone of the Devonian formation at the
Falls of the Oiuo, uii Uiu JieiUucky side of the river,

Platyceras unguiforme. HALL.

Platyceras unguiforme, Hall. Pal. N. Y., Vol. 3, p. 322—1859.

Shell oblique, arcuate, sub-spiral ; volutions one or two, more or less con-
tiguous at the apex ; last volution angular, extending in a straight or slightly
curved direction towards the aperture. Aperture oblique, sub-ovoid; peris-
tome sinuous'

Surface longitudinally plicate, and marked by fine, crowded, undulating
lamellose striae. The plications are of unequal size; they are flat and broad
on the dorsal side, and angular and smaller on the ventral side. These plica-
tions increase in number by bifurcation.

Formation and Locality. — Found in the Niagara limestone in the quarries east of the city of Louis-
ville, Ky. It is a rather rare shell.

Platyceras ventricosum. CONBAD.

Plate XXV., figure 10.

Platyceras ventricosum, Conrad. Ann. Rep. N. Y. — 1840.
Platyceras ventricosum, Meek and Worthen. 111. Geol. Rep., Vol. 3 — 1868.

Shell obliquely sub-ovate ; composed of two and a half to three very rapidly
enlarging contiguous, volutions, the last one of which is very large and ven-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 169

tricose ; spire depressed below the upper side of the body-whorl. Aperture
very large and circular ; inner lip usually in contact with the spire, so as to
leave a moderately large umbilical cavity. Surface traversed by fine striae,
and near the aperture coarser, somewhat undulated lines of growth, crossed by
faint traces of extremely fine, revolving lines. General size differs in different
individuals ; the illustration shows a specimen of average size.

Formation and Locality. — Found in the Corniferous limestone of the Devonian formation in
Jefferson county, Ky., and in Clark county, Ind.

D'Archiac and DeVemeuil.

Murchisonia, D'Archiac and Verneuil. Bull. Soc. Geol. Fr., Vol. 12 — 1841.
Etymology : Named after Sir R. I. Hurchison, of England.

This genus was proposed by D'Archiac and De Verneuil, to include Buccin-
uni spinosum and B. abbreviatum of Sowerby, Turritella bilineata of Gfoldfuss,
and others. Shells spiral, with very elevated spire and many volutions,
marked by a spiral band and bent striae; body very elongate, with a notch or
slit in the outer lip of the aperture, or where this is wanting, the striae are
bent, indicating the slit. Murchisonia are a sort of elongate Pleurotomaria.
Type, Murchisonia bilineata.

Murchisonia desiderata. HALL.

Plate XXVI., figure 8.

Murchisonia desiderata, Hall. Descpt. of New Sp. of Foss. — 1861.
Murchisonia desiderata, Hall. 15th Rep. N. Y. St. Cab.— 1862.
Murchisonia desiderata, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 89—1885.

Shell elongate, turretiform ; spire somewhat rapidly ascending. Volutions
ten or more, and obtusely angular, flattened on their upper sides, and a little
more convex below the spiral band. The volutions, from apex to aperture, are
gradually enlarging. The greatest width of the last volution is about equal
to the combined height of the second and third whorls, but scarcely more ven-
tricose than the preceding one, except towards the aperture. Aperture some-
what elongate ; the columellar lip thickened and bounded by a well-marked
callosity.

Surface marked by distinct, concentric striae, which are sometimes raised
into fascicles above the general surface of the shell, and, bending gently back
from the suture, reach the spiral band, crossing which, they bend forward more
abruptly, making a gentle curve to the suture below. The spiral band, at about
three-fifths of the width of the volution below the suture, is simple, flattened
or slightly concave, limited by narrow, moderately elevated revolving lines,

GEOL. SUK. — 22

170 PALAEONTOLOGY OF KENTUCKY.

and marked by the retrorsely curving striae, which are less prominent upon it
and the adjacent parts than near the suture. Suture close.

The dimensions and general size of the shells belonging to this species are
given in the illustration, which shows the natural size of the specimen from
which it was made.

The specimen before me is an internal cast, but it is covered by a thin coral
bearing on its whole surface small tubercles, as shown in the illustration, but
not placed with such a regularity as the draughtsman has given them in the
figure. This incrusting, tuberculose coral was mistaken for the real shell of
the fossil.

Formation and Locality.— Found in the cherty layers of the Devonian formation at and around
the Falls of the Ohio, in Kentucky and Indiana.

Mlirchisonia petilla. HALL AND WHITFIKLD.

Plate XXXI., figure 5.

Murchisonia petilla, H. and "W. 24th Eegent's Rep., p. 186 — 1872.
Murchisonia petilla, H. and W. 27th Regent's Rep., pi. 13 — 1875.

Shell small, spire elevated, slender and regularly tapering from base to
apex ; volutions about twelve gently and regularly expanding from the apex ;
moderately convex, somewhat obtusely subangular below the middle ; last one
scarcely ventricose.

Aperture sub-rhomboidal. Surface not known, the specimen being an ex-
foliated internal cast. Length of the specimen one inch ; diameter of last volu-
tion seven-twentieths, and height one-fifth of an inch.

Formation and Locality. — Occurs in the lower strata of the Niagara rocks in the quarries east of
the city of Louisville. The specimen illustrated and described is, so far, the only one known; it belonged
to the collection of the late Dr. James Knapp.

Genus Pleurotomaria.

Do France.

Pletirotomaria, De France. Diet. Sci. Nat., 41 — 1826.

Etymology: pleura, side; tome, cut or notch, having a deep cut or notch in the outer lip.

Shells spiral, trochiform, solid, few-whorled, with the surface variously
ornamented ; aperture subquadrate, with a deep slit in its outer margin. The
part of the slit which has been progressively filled up forms a band round the
whorls or volutions. This slit, in the outer lip of the aperture, on which the
name has been founded, is seldom visible, as specimens are rarely found per-
fect ; but the peculiar bending of the transverse striae, curved backwards to
and marking the line of the slit, are always a prominent character of this
genus. (Copied from Woodward's Manual and Portlock's Report on London-
derry.)

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 171

PleUTOtOmaria Casii. MEEK AND WORTHEX.

Plate XX VI., figure 11.
Pleurotomaria cusii, M. and W. 111. Gcol., Vol. 3, p. 359—1868.

Shell attaining a rather large size, higher than wide; spire conical, a little
more than equalling length of lower half of body volution. Whorls about
five and a half, very convex; those of the spire each showing three- fourths of
its entire height above the next succeeding one ; upper ones (in casts) rounded,
last one large and ventricose, and, like the next above, sub angular around near
the middle, below which it is somewhat produced, and rounds into a small,
umbilical opening in the cast, probably entirely closed by the columella in
specimens retaining the shell. Spiral band apparently of moderate breadth,
occupying the obtuse angle a little above the middle of body-whorl, and pass-
ing around near the middle of the others. Suture deep in consequence of the
great convexity of the volutions.

Aperture sub- circular. Surface of internal casts showing, on the upper con-
vex slope of the body- whorl, and that of the next above it, obscure transverse
ridges, curving backwards as they extend out from the suture, probably par-
allel to the lines of growth. Crossing these, there is an undefined, revolving
ridge on the body-whorl a little more than half way out from the suture
towards the spiral band. Other surf ace- markings are unknown. (Copied from
Meek and Worthen's description in Vol. 3, of Geol. Rep. of Illinois.)

This species is easily distinguished by the transverse striae, on the upper
side of its body- whorl, from all other Silurian Pleurotomaria.

Formation and Locality. — In the Niagara limestone of the quarries east of the city of Louisville,
Ky. A rather rare species.

Pleurotomaria arabella. \. SP.

Plate XXVI., figure 12.

Shell rather large, tilfbinate, spire elevated ; apex minute, aperture sub-
quadrate, apparently somewhat wider than high. Volutions five or six, prom-
inently convex ; rapidly enlarging, last one or body-whorl very ventricose.
Shell wider than high.

Surface marked by three revolving carinae, of which one is above and the
other two below the peripheral band ; the band itself is flat and narrow, and
not limited by elevated carinae ; the upper part of the volution, at least in the
two last ones, is gently sloping from suture to the first or upper carina; from
this it curves to the spiral band, forming a moderately deep, rounded furrow.

The interspaces between band and second carina, and between this and the
third or last carination, are also rounded depressions, of which only the one

172 PALEONTOLOGY OF KENTUCKY.

next to the baud is of about equal depth with the furrow in the upper half ;
the second depression in the lower half is shallow. In consequence of the
great convexity of the volutions the suture is deep. The character of the
transverse striae is only indicated but not fully known.

Formation and Locality.— In Hie Cornifcrous limestone in Jefferson county, Ky., and in Clark
county, Ind. My specimen is only an internal cast, from which the surface-markings, with the exception
of the revolving ctirmae, are obliterated. 1 have compared this shell with all the different species of Pleu-
rotomaria known to me, but can not place it with any one, and 1 am thus compelled to make a new species
for its reception.

Pleurotomaria lucina. HALL.

Kuomphalust rotundas, Hall. Geol. of N. Y., Surv. of 4th Di&t.— 1843.
Pleurotomaria lucina, Hall. Descpt. of New Sp. of Foss., p. 14—1861.
Pk'iirolomaria liicirut, Hall. Fifteenth Keg. Kep., pi. 42 — 18G2.
Pkur. rotunda and P. lucim, Hall. 111. of Dev. Foss. Gastrop, pi. 8— 187G.
Pleur. lucina, Hall. Pal. N. Y., Vol. 5, part. 2, p. G7— 1879.

Shell sub-globose or obliquely ovoid-conical. Spire moderately elevated ;
apex minute ; volutions about four, gradually expanding to the last one, which
comes very regularly ventricose, with the aperture expanded and nearly round,
extended on the lower side, with a shallow notch on the anterior margin ; upper
side of the volutions very symmetrically convex ; suture neatly defined,
slightly canaliculate ; lower side of the body- volution convex in the middle,
and abruptly curving into the umbilical depression.

Surface beautifully cancellated by concentric and revolving striae, which, in
many specimens, are of equal strength. Periphery marked by a moderately
wide band, on which the striae are turned abruptly backwards ; this band is
limited by stronger striae or narrow ridges on each side, sometimes with one or
two slender revolving striae within the limits of the band, making a narrow
space, which is often crenulated by the concentric striae.

This species is well marked by its symmetrically rotund form, with moderate
elevation of the spire, and the regular convexity of the volutions, even in casts
of the interior when not compressed. There is some variety in the surface-
markings of specimens apparently belonging to this species. The concentric
striae are sometimes much coarser than the revolving ones ; and finer striae are
implanted between the stronger ones, and do not reach the suture-line. In
old specimens the revolving band is sometimes nearly a quarter of an inch
wide. A very symmetrical specimen has a diameter of a little more than two
inches, and is nearly an inch and three-fourths in height.

Formation and Locality. — Found in the Cornifcrous limestone, at and around the Falls of the
Ohio, in Kentucky and Indiana, but generally as internal casts, which show only the general form, but not
the surface-markings of the shell.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 173

Pleurotomaria procteri. ». *r.

Plate XXI., figures 9, 10 and 13.

Compare Pleurotomaria capillaria, var. of Pal. N. Y., Vol. 5, Part 2, text, page 87, and Pleur. capillarin,
var. rustica, of Pal. N. Y., Vol. 5, Part 2, Plates, Plate 30, figures 20, 21 and 22.

Shell trochii'orm ; height exceeding width about one-fourth or more. Volu-
tions from five to six, somewhat rapidly increasing in size, the last one ventri-
cose ; there is only one carina above and one below the peripheral band : the
carina above the band gives to upper portion of the volution a sub-angular
appearance, while the lower part is regularly rounded. The peripheral band is
divided by a somewhat finer central carina, which is crossed rectangularly by
strong striae, which only extend from margin to margin of the peripheral band,
with interspaces of about four times their own size. These rectangular striae
are entirely separated from the striae of the upper or lower half of the volu-
tion ; they give the dividing carina a beautifully crenulated appearance. On
both sides of the peripheral band, the siirface is ornamented by strong trans-
verse striae ; in the upper half they start from the suture, and run in an almost
straight line, with a backward deflection of about ten degrees, to the first carina,
from where they curve slightly backward to the upper marginal carina of the
peripheral band. This system of striae, interrupted by the band, continues at
the lower marginal carina of the latter, from where the striae extend in slightly
curved or nearly straight lines with a forward deflection, either to the sutures
of the upper volutions, or to the lower carina of the body-whorl. From this
lower carina, which forms the suture-line of the upper whorls, and which is,
therefore, only visible on the last volution, the striae curve gently to the um-
bilicus and to the columellar lip; but a great number of them die out or become
extinguished at different distances from the lower carina. All the volutions
are, in their transverse section, extremely convex, which gives them very deep
sutures, and separates them from each other in a very decided manner. The
aperture of this shell is not known, inasmuch as in all the specimens in niy
collection the outer lip is missing.

This species stands between P. sulcomarginata and P. capillaria, both of
which it resembles in some respect, but it is easily distinguished from the first
by its more elevated spire, its larger size, and the difference in the number and
arrangement of the revolving carinae ; from the latter by the greatly smaller
number of revolving carinae, and from both here named, and all other species
of the genus Pleurotomaria, by the crenulated central carina in the peripheral
band, which is very characteristic in P. procteri.

Formation and Locality. — Associated with P. sulcomarginata in the Corniferous limestone of Jef-
ferson county, Ky., and of Clark county, I ml. It is a somewhat rare species. This beautiful shell I narno
in honor of Kentucky's State Geologist, Prof. John R. Procter, who has served his State with great dis-
tinction, and who has labored, more than any other man, to bring the great mineral wealth of Kentucky to
the knowledge of the people at large.

174 PALEONTOLOGY OF KENTUCKY.

Fleurotomaria sulcomarginata. CONRAD.

Plato XXI., figures 11 and 12.

Pleur. sulcomargmata, Conrad. Jour. Acad Nat. Sc. Phil., Vol. 8 — 1842.
Plcur. sulcomarginata, Hall. Descript. of New Sp. of Foss., p. 18— 18C1.
Pleur. sulcomarginata, Hall. Fifteenth Rep. N. Y. St. Cab. — 18G2.
Pleur. sulcomarginata, Hall. Illust. of Dev. Foss. Gastr., pi. 19—1870.
Pleur. sulcomarginata, Hall. Pal. N. Y., Vol. 5, part 2, p. 69—1879.

Shell depressed trochiform ; spire moderately elevated ; apex minute. Volu-
tions four or five, very depressed convex on the upper side, gradually enlarging
to the last one, which becomes somewhat ventricose. Aperture subquadrate,
somewhat wider than high, the columella much extended below.

Surface ornamented by two distinct, narrow, revolving carinae on each
volution, one just below the suture and the other near the periphery, with
finer intermediate striae, which are rarely visible ; the entire surface marked
by strong, regular and even concentric striae, which crenulate the revolving
carinae, and, passing over the lower one, bend backward to the concave per-
ipheral band. Sutures sometimes sharply canaliculate. In entire specimens,
the apex is very minute, and, when the outer carination is crenulated by the
strong transverse striae, the shell has a coronate aspect. This carination, how-
ever, is often obsolete on the outer volution, and is more rarely noticed on the
next above, and the striae then continue uninterruptedly, bending backward
to the peripheral band, and continuing on the lower side, often very nearly of
the same strength as above. There is frequently a narrow depressed band just
below the peripheral band on the last volution, causing a slight deflection of
the striae. The striae are usually finer, and sometimes become nearly obsolete
below the outer carination, and more rarely on other parts of the shell, espe-
cially near the aperture.

Formation and Locality. — Found very abundantly in the cherty layers of the Corniferous lime-
stone around the Falls of the Ohio, in Kentucky and Indiana, and very often in very fine and well pie*
Served specimens.

Genus Callonema. nan.

Calloncma, Hall. Pal. N. Y., Vol. 5, pi. 2.
Etymology: kallos, beautiful; nema, a thread.

Shell sub-globose, turbinate or ovoid-conical. Volutions rounded or some-
times sub-angular above and below ; outer lip apparently thin ; columellar lip
thickened and spreading over the volutions above and extended below; axis
umbilicate.

Surface marked by fine, even striae, which extend equally over the volutions,
rarely divided, and sometimes merging into the ordinary striae of growth, and

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 175

extending into the umbilicus. The chief external characters of this genus
being the sharply elevated, even, thread-like, concentric striae traversing the
volutions above and below, a distinct columellar lip, and an umbilicate axis.

Callonema bellatula. HALL.

Plato XX., figures 4, 5, 6 and 7.

Laxonema bellatula, Hall. 14th Rep. N. Y. St. Cab., p. 104—1861.
Isonema bellatula, Meek. Proc. Acad. Nat. Sci. Phil., p. 252 — 1865.
Isonema bellatula, Meek. Geol. Surv. of 111., Vol. 3, p. 443—1868.
Isonema bellatula, H. and W. 27th Regent's Rep., pi. 13—1875.
Isonema bellatula, Hall. Illust. of Dev. Foss. Gaster., pi. 14 — 1876.
CaOanema bellatula, Hall. Pal. N. Y, Vol. 5, pt. 2, p. 51—1879.

Shell sub-ovoid-conical ; spire elevated and rapidly expanding below. Volu-
tions about six or seven, the upper ones minute, and somewhat gradually ex-
panding to the third or fourth whorl, and more rapidly below, the last one being
very ventricose, regularly rounded or obtusely subangular towards the base.
Aperture apparently transverse ; the specimen before me, and represented by
figure 7, is perfect, with the exception of the peristome, of which the outer lip
is missing ; I am, therefore, unable to state the exact form of the aperture ; col-
umellar lip thickened, spreading above and extended anteriorly. In my speci-
men the umbilicus is partly open, and partly closed by the columellar lip.

Surface is covered by regular, even, sharply elevated striae, with about equal
interspaces, which are slightly turned backwards from the suture, and gently
curved to the base of the volution, and on the last one curving over the per-
iphery with equal strength ; a portion becoming obsolete and others coalescing
and becoming stronger as they enter the umbilical depression. Some specimens
of this species show an obtuse angularity at the base of the last volution, as
slightly indicated in figure 6 ; but most shells are regularly rounded and ven-
tricose. There is no specific difference between these two forms. This species
has a close resemblance to Callonema lichas, with which it may even be identi-
cal.

Formation and Locality. — Occurs in the Corniferous limestone at and around the Falls of the Ohio
in Kentucky and Indiana, and belongs to the rarer forms.

Callonema clarki. N. sr.

Plate XXIV., figures 2, 3, 4 and 5.

Shell above medium size ; sub-hemispherical ; spire moderately elevated,
more or less so in different shells, as shown by the two specimens illustrated,
consisting of from three to five volutions. The volutions are regularly increas-
ing from apex to aperture, which is sub-circular or subquadrate; they are
depressed convex on their upper

176 PALAEONTOLOGY OF KENTUCKY.

The columella is much extended below. Suture small and shallow, between
the upper volutions scarcely noticeable. The surface appears, to the naked
eye, entirely smooth, but under a magnifier shows fine, transverse striae, closely
set between some stronger marked lines of growth. These striae and lines of
growth extend from the suture down and backwards to the umbilical depres-
sion. The last volution, or the body-whorl, as it is also called, curves very
abruptly at its middle, and slopes from there in a straight or slightly curved
line to the inner lip of the aperture, making the lower half of the last volution
either flat or only very little convex. The apex appears to be very minute in
perfect specimens. Figure 4 I consider to be the normal form, while figure 2 is
either an aberration or the result of a slight compression.

Formation and Locality. — This species occurs in the rotten hornstone of the Devonian formation
and was found by Dr. E. S. Clark in the Devonian clay topping the Niagara rocks east of the city of
Louisville. I name this heretofore undescribed species in honor of Dr. Clark.

Callonema imitator. HALL AND WHITFIELD.
Plate XX., figures 12 and 13.

Pleurotomaria imitator, H. and W. 24th Eegent's Ileport, p. 195 — 1872.
Pleurotomaria imitator, H. and W. 27th Eegent's Report, pi. 13 — 1875.
Callonema imitator, Hall. Pal. N. Y., Vol. 5, par£2, p. 52—1879.

Shell of large size, sub-hemispherical ; spire moderately elevated, consisting
of four or five rounded volutions, regularly increasing from the apex to the
aperture, which is sub-circular ; rounded below and broadly umbilicate ; suture
distinct, not channeled, situated at the periphery of the preceding volution.
Surface of the upper sides of the volution marked by strong ridges, which
have a slight bend just below the suture, and thence curve backward to the
periphery, gradually increasing in strength from apex to outer volution,
on the middle of which they are in the ratio of about twenty to an inch;
on the outer half of the last volution they become gradually obsolete, or
merge into the lines of growth, which also mark every part of the surface.

Below the periphery there are apparently none of the ridges existing. This
species is very similar to Pleurotomaria lucina in form, being a little more
depressed, and the volutions less rapidly increasing. The surface-markings
are more nearly like those of Pleur. arata, while the volutions are more ventri-
cose on the upper side, and the periphery is apparently destitute of a band or
sinus, which is a distinguishing feature.

Formation and Locality. — In the rotten hornstone of the Corniferous group, in Jefferson county,
Ky., and in Clark county, Ind. Earely found. Only a few specimens are known 'outside of Dr James
Knapp's collection. A good interior cast is in my own cabinet.

FOSSILS OF THE SILURIAN AKD DEVONIAN ROCKS. 177

Genus Loxonema. phniips.

Lotonema, Phillips. Palaeoz. Fossils— 1841.

Etymology : loxos, oblique); nema, a thread — alluding to the oblique thread-like striae.

Shell spiral, turriculated ; whorls or volutions convex, their upper edges
pressed against the next above ; without spiral band ; mouth oblong, attenu-
ated above, effused below, with a sigmoidal edge to the right lip ; no umbil-
icus (?).

Surface covered by longitudinal threads, and ridges generally arched. (Geol.
Rep. of Londonderry, by J. E. Portlock.)

Loxonema sinuata is the type of this genus.

Loxonema hamiltoniae. HALL.

Plate XXXI., figure 29.

Loxonema hamUtoniae, Hall. Dcscpt. of New Sp. of Foss. — 1861.
Loxonema hnmillonine, Hall. 15th Regent's Rep. — 1862.
Loxonema hanrittoniae, Hall, lllust. of Dev. Foss., pi. 13 — 1876.
Loxonema kamiUoiiiae, Hall. Pal. N. Y., Vol. 5, pt. 2, p. '45— 1885.

Shell elongate, subulate ; volutions moderately convex, numbering from ten
to thirteen ; as many as the last number were counted in the largest specimen
known. The volutions are gradually increasing in size from the very minute
apex to the aperture ; the last one becomes ventricose. Aperture ovate, nar-
rowing below, colutnella extended.

Surface marked by longitudinal, sharp, curving striae, which bend gently
backward from the suture, and forward to the base of the volution, having
the greatest curve near the middle, those of the last volution curving abruptly
backward to the columellar lip. Striae separated by distinctly defined grooves,
which are a little wider than the ridges, the striae increasing in distance as the
shell grows older. In the specimen figured, the apical volutions are missing ;
the draughtsman restored them, but he made the volutions too high, and not
enough in number. The height of the figure would have been the natural size
of the shell when complete ; it should have shown twelve volutions instead of
its present nine. It measures seventeen lines in length, and its body-whorl
has a diameter of four lines. This species is associated with L. hydraulica,
which it resembles in its surface-markings, but it may be easily distinguished
from that shell by the different shape of the volutions and suture. In L. hy-
draulica the whorls are very convex, while in L. hamiltoniae they are only
moderately curved ; the suture in L. hydraulica is very deep and constricted,
that of L. hamiltoniae comparatively very shallow. Besides, the spire in L.

hamiltoniae is more elongate than that of L. hydraulica.

•

Formation and Locality. — Occurs in the chert bed which overlies the hydraulic cement rock at the
Falls of the Ohio, on the Kentucky shore of the river, and also at Watson's Station, on the Ohio and
Mississippi Railroad, in Clark county, Ind.
a KOI., suu. — 22

178 PALAEONTOLOGY OF KENTUCKY.

Loxonema hydraulicum. HALL AND WHITFIELD.

Plate XX., figures 8 and 9.

Loxonema hydmulica, H. and W. 24th Regent's Rep., p. 193—1872.
Loxonema hydrautica, H. and W. 27th Reg. Rep., pi. 13—1875.
Loxonema hydraulica, H. and W. Illust. of Dev. Fossils, pi. 13 — 1876.
Loxonema hydraulicum, Hall. Pal. N. Y., Vol. 5, part 2, p. 44 — 1879.

Shell turreted ; volutions rounded, from live to eight and more ; greatest
convexity about the middle of each ; upper ones always missing, and, therefore,
unknown. Sutures deep, giving a constricted aspect at the junction of the
volutions.

Surface marked with distinct, angular striae, bending gently backward from
the suture to the periphery, and with a longer forward curve to the base of
each volution; those of the last volution bending more abruptly backward,
and making a second abrupt retrorse curve to the columellar lip.

This species, in the rotundity of the volutions, and the constriction at the
sutures, contrasts with all the other species of this genus here described.

Formation and Locality. — Found rather plentiful in the cherty layers overlying the hydraulic
limestone of the Devonian formation, at and around the Falls of the Ohio, in Kentucky and Indiana,
associated with Lox. laeviusculum and Lox. rectistriatum.

Loxonema laeviusculum. HALL.

Plate XXII., figures 8 and 9.
Loxonema laeviitsculum, Hall. Pal. N. Y., Vol. 5, part 2, p. 131—1879.

Shell elongate, subulate ; volutions from nine to twelve ; rounded and some
what rapidly expanding to the last one, which is moderately ventricose. Su-
ture close and simple. Aperture ovate; the columellar lip much extended
below.

Surface nearly smooth, or marked by faint, obsolescent striae, which are
moderately curved over the convexity of the volution, and become fasciculate
on the lower side of the last one as they approach the columellar lip.

This species has the general aspect of Loxonema hamiltoniae, but it is less
rapidly tapering towards the apex, the volution somewhat less convex, and the
last one not so ventricose as in well preserved specimens of that species. Usu-
ally the specimens have the appearance of being worn and macerated, and the
general absence of striae upon the surface may be due in part to this cause ;
but they are associated upon the same surface with L. hydraulicum, which,
in similar conditions, has retained its surf ace- striae in good preservation. This
species is readily distinguished from L. hydraulicum by the less rounded volu-
tions and slighter constriction at the suture. It is more rapidly tapering than

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 179

L. rectistriatum, with which it is also associated, and has no constriction of the
upper part of the volution as in that species.

A specimen preserving nine volutions, including the last one, measures about
one inch and a quarter.

Formation and Locality. — Occurs in the cherty layers above the hydraulic limestone of the Devo-
nian formation, at and around the Falls of the Ohio, in Kentucky and Indiana. Not as abundant as its
associate, the Lox. hydraulicum.

Loxonema rectistriatum. HALL.

Loxonema rectistriatum, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 131 — 1879.

Shell elongate terete ; volutions probably twelve and more in number; mod-
erately convex, very gradually increasing in size ; the last one being scarcely
more ventricose than the preceding ; each volution is distinctly contracted a
little below the close suture, and then expanding, gives the greatest convexity
near the lower third. Suture line close ; aperture ovate, with the columella
extending below.

Surface marked by slender, gently curving, longitudinal striae, which bend
backward from the suture to bottom of constriction, and then continue to
the base of the volution, those of the last one curving gently forward to the
columellar lip. The spaces between the striae are from one and a half to twice
the width of the ridges.

This species may be distinguished from any other described of the genus
Loxonema, by the finer longitudinal striae, which are scarcely curved on the
body of the volution, and also by the constriction of each volution just below
the suture-line. The striae are stronger on the upper volutions, gradually be-
coming finer and less prominent on the lower ones, though continuing distinct
throughout. A specimen, which preserves about eight volutions from the
aperture, measures a little more than one inch in length.

Formation and Locality. — Found associated with Lox. hydvaulicum and Lox. laeviusculum, in the
cherty layers superimposed upon the hydraulic limestone of the Devonian formation at and around the
Falls of the Ohio, in Kentucky and Indiana. Prof. Hall's descriptions and illustrations of this species, and
of those just mentioned as its associates, were made from specimens belonging to the cabinet of the late Dr
James Knapp, who collected them at the Falls of the Ohio on the former Corn Island.

Genus Macrocheilus.

Phillips.

Macrocheilus, Phillips. Pal. Fossils — 1841.
Etymology: macros, long; and cheilos, a lip.

Synonym: Polyphemopsis, Portlock.

Shell thick, ventricose, buccinoid ; aperture simple, effuse below ; outer lip
thin, inner lip wanting; columella callous, slightly tortuous. Type: Macro-
cheilus arculatus of Schlotheim. (Copied from Woodward's Manual.)

180 PALAEONTOLOGY OF KENTUCKY.

Macrocheilus carinatus. N. SP.

Plate XX., figures 20, 21, 22 and 23.

Shell of medium size, turreted, sub- fusiform ; length less than twice the
diameter ; volutions four or five, gradually increasing from the apex, last
two ventricose, and the last one occupying one half the length of shell.

Aperture not known ; indications point to its being elongate. No surface-
markings are visible ; they may have been obliterated by the process of silici-
fication, to which our specimens were subjected. A peculiarity of this shell
is the carina on the periphery of the last volution, as plainly shown in figures
20 and 23. It is in fact not a real carina, but produced by the elevation of the
lower half of the volution above the surface of the upper half. This species
has some resemblance to M. hebe, but differs from it by the peculiar feature of
its lower volution.

Formation and Locality. — Found in the Corniferous limestone of the Devonian formation at and
around the Falls of the Ohio, in Kentucky and Indiana.

Genus Polyphemopsis, Poniock.

Polyp hemop sis, Portlock. Geol. Hep. of Londonderry — 1843.

Etymology: polyphemus, a genus of shells; opsis, appearance — having the appearance of Poly-
phemus.

Portlock does not give a definite description of the genus ; but from his
article on the subject, the following description may be formulated :

Shell free, univalve elongated, with a mammillated spire ; mouth narrow ;
columella smooth and truncated ; base notched ; the last whorl greater than
the balance together ; base of the columella curved ; outer lip is not margin-
ated, and does not form on the whorls any suture or varices which might indi-
cate the position of former apertures.

This is the description of Montfort's genus, Polyphemus, from which Port-
lock's Polyphemopsis differs by its sharp spire, while Polyphemus has a mam-
millated one, and by the want of a wave in outer lip of the aperture.

Polyphemopsis louisvillae. HALL AND WHITFIELU.

^Plate XX., figures 16, 17, 18 and 19.
Polyphemopsis louismllae, H. and W. 24th Reg. Eep., p. 193 — 1872.

Shell small, ventricose, consisting of about six rapidly tapering volutions,
the last of which comprises about two-thirds the entire length of shell. Aper-
ture large, ovate, widest below the middle, and pointed at the upper angle ; a
little more than half as long as the shell. Columella slight ; suture scarcely
impressed.

FOSSILS OF THE SILURIAN ANL> DEVONIAN ROCKS. 181

Surface smooth ; figures 16 and 17 are of natural size, while figures 18 and 19
are enlarged to two diameters. Figures and description made from specimens
belonging to the collection of the late Dr. James Knapp.

Formation and Locality. — Occurs in the hydraulic limestone of the Devonian formation at the
Falls of the Ohio, in Kentucky and Indiana.

Genus Euomphalus.

Euomphalus, Sowerby. Minn. Conch., Vol. 1 — 1814.
Etymology: eu, wide; omphalos, umbilicus,

The type of this genus is Euomphalus pentagonalis. Shell depressed or
discoidal ; whorls angular or coronated ; aperture polygonal ; umbilicus very
large ; operculum shelly, round, multispiral. The genus Euomphalus is nearly
related to Straparollus of Montfort, and to Phanerotinus of Sowerby. It is dif-
ficult to mark out any features of importance in which these three genera differ.
Prof. Hall uses the name Straparollus in a sub-generic sense for those shells
with close rounded volutions, where the spire rises moderately above the plane
of the outer volution, while those shells with disjointed volutions form the
genus Phanerotinus.

Euomphalus decewi. BILLINGS.

Plate XXI. figures 1 and 2.

Euomphalus decewi, Billings. Can. Jour., p. 358 — 1861.
Euomphalus conradi, Hall. 14th Reg. Rep., p. 107 — 1861.
Euomphalus decewi, Meek. Geol. Rep. Ohio Pal., Vol. 1 — 1873.
Euomphdlus decewi, Hall. Illust. of Dev. Poss., pi. 15 — 1876.
Euomphalus decewi, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 65—1879.

Shell discoid, upper side moderately concave or sometimes nearly flat, the
lower side broadly and deeply concave. Periphery moderately convex or
nearly flat, and slightly oblique to the plane of the shell ; sometimes, in the
casts of young shells, gently rounded from the upper margin to the edge
of the umbilical depression. Volutions three or four (there are rarely more
than two or three preserved in the casts), inner ones rounded, gradually be-
coming depressed on the upper and lower sides. The periphery, at first
rounded and undefined, becomes more flattened and distinctly limited by a
defined angularity above and below, becoming more flattened towards the
aperture ; the upper side being gently depressed, while the lower side grad-
ually assumes a more abruptly concave aspect, forming a broad umbilicus.
Aperture unknown; section of the outer volution sub-quadrilateral or tri-
angular, with the inner angle truncated.

182 PALEONTOLOGY OF KENTUCKY.

Surface, in young specimens, marked by fine elevated striae of growth. The
fossils has a diameter of from one to four inches.

This species occurs usually as internal casts ; in those of older specimens
the apex is decollated, and the termination smoothly rounded, as if separated
by a septum, no evidence of a continuation above being perceptible. The
interior volutions being rounded, the angularity on the upper side is scarcely
noticeable before the end of the second volution, and that of the lower side
about the same time or a little later. In some of the casts of the interior there
is a low, undefined angularity upon the back of the shell. This species ap-
pears to be nearly identical with Euomphalus wahlenbergii of Goldfuss (Petre-
facta, vol. 3, p. 82, pi. 189, figs. 7, a, &), found in the limestone of the Eifel.
That species also presents the same features in the decollation of the earlier
volutions, and the rounded apical extremity. That European form is associated
with Euomph. planorbis, a species much resembling our Euomph. clymen-
ioides, which occurs in the same beds with Euomph. decewi, in western local:-
ties.

Formation and Locality. — Found abundantly in the Corniferous limestone in Jefferson county,
Ky., and Clark county, Ind. A specimen containing the shell is figured in Geol. Ohio Pal., Vol. 1.

Euomphalus sampsoni. N. SP.

Plate XXI., figures 3 and 4.

Shell discoid, but generally, by apical decollation, receiving the shape of a
horn; both sides considerably concave ; the periphery broadly convex. Num-
ber of volutions unknown, probably only two. The outer volution rapidly
increasing in size; its cross-section near the apex circular, near the aperture
oval. The surface is ornamented by from twenty-five to thirty strong, simple
plications, each of which extends over the whole length of the outer or last
volution, and may probably reach back to the apex. These plications increase
in strength from apex to the aperture; their interspaces are also gradually
widening in their course towards the front ; they are of unequal width ; some
are of four times, and others of double the size of the adjacent ribs. My
specimens, being internal casts completely silicified into hornstone, no other
surface-markings are retained.

Form and size of the aperture unknown. This species, with decollated apex,
showing only a horn of not quite a whole volution, resembles somewhat Prof.
Hall's Nautilus liratus, with which I confounded it, when I found the first
specimen, but I soon discovered my mistake. Hall's Nautilus shows plainly
the transverse lines of the septae, which do not exist in our shell ; in the latter
the curvature is greatly stronger than in the former, and the increase in the
size of the outer volution is more gradual in my species than in the Nautilus.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 183

The specimen illustrated on plate 21 is about of average size, and represents
the general condition of most of the specimens so far found.

Formation and Locality. — Found in the cherty layers superimposed upon the hydraulic limestone
of the Devonian formation, at Watson's Station, in Clark county, Ind., about six miles from the Falls ot
the Ohio. This species is named to honor a gentleman who cultivates, not only for himself, different
branches of Natural Science, among which most prominently, Geology and Palajontology, but who also
endeavors to popularize the same by forming scientific societies in his western home. It is named after the
Hon. F. A. Sampson, attorney at law, Sodalia, Missouri

Genus Platyostoma. conrud.

Platyostoma, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. 8—1842.
Etymology : platys, broad ; stoma, mouth.

Mr. Conrad gives the following very meager description of this genus :
Shell sub-globose ; spire short ; aperture very large, sub-orbicular, dilated ;
labrum joining the body-whorl at right-angles to the axis of shell. The
species, Platyostoma niagarensis or P. lineata, may be taken as the type for
this genus. The shells of this genus are related to those of Platyceras, with
depressed spire, but they differ by the larger number of their volutions and the
more gradual increase in the size of the whorls.

Flatyostoma lineata. CONRAD.

Plate XXI., figures 7 and 8, and Plato XIX., figures 6, 6, 7 and 8.
, Platyostoma lineata, Conrad. Jour. Acad. Nat. Sci. Phil., Vol. 8—1842.
Platyostoma lineata, Hall. Illust. of Devonian Foss., Gast.. pi. 9 — 1876.
Platyostoma lineata, Hall. Pal. N. Y., Vol. 5, part 2, p. 21—1876.

Shell above medium size, depressed spiral ; each volution elevated moder-
ately above the succeeding one ; number of volutions seldom exceeding four ;
apex being usually imperfect. The outer volution large and very ventricose ;
it is regularly convex, with the exception of the portion near the suture line,
which is generally a little depressed or concave. Aperture sub-rhomboidal,
with thin outer lip and a sharp entire margin ; columellar lip thickened, folded
and renexed over the umbilicus, which is entirely closed in adult speci-
mens.

Surface marked by fine, nearly equidistant, thread-like revolving striae, as
seen in figures 5 to 8, plate 19. which are cancellated by fine concentric striae
of about the same strength, but of unequal distance ; the latter sometimes
bend abruptly backward upon the back of the shell, indicating a sinus in the
lip at some period of growth, and are frequently crowded in fascicles, giving
a rugose appearance to the surface of the shell. In well preserved specimens
the surface is beautifully cancellated; and in worn and partially exfoliated

184 PALAEONTOLOGY OF KENTUCKY.

specimens, some of the surface-markings remain visible ; the revolving striae
are generally the first which become obliterated. This species is very variable
in size ; we find specimens as small as half an inch or less, and, again, others
measuring even more than two inches. The individuals illustrated on plates
19 and 21 are about of average size.

Formation and Locality. — Found abundantly, in even well preserved specimens, however, without
the revolving striae, in the rotten limestone of the Corniferous group, in Jefferson county., Ky., and in
Chirk county, lnd.

Flatyostoma lineata, var. callosa. HALL.

Plate XXI., figure 14; Plate XXII., figures 10 and 11, and Plate XXV., figures 5, 0 and 7.

Plaiyostoma lineata, var. callosa, Hall. Illust. of Dev. Fossils, Gasteropoda, pi. 9 — 1876.
Platyostoma lineata, var. callosa, Hall. Pal. N. Y., Vol. 5 — 1879.

This variety has the general form and also the surface-markings of specimens
of the species Plat, lineata, with the exception that in this variety the spire
is extremely depressed, scarcely extending above the upper level of the volu-
tion of habitation, which is generally called the body-whorl. The aperture is
large, sub orbicular, with the peristome slightly sinuate on the upper side near
its junction with the preceding volution. The inner lip is marked by a thick-
ened callus, not observed in any other specimens ; the callosity extending into
the lip below, which thence assumes the ordinary features of the species.

Formation and Locality. — Found associated with Plat, lineata in the rotten hornstone of the
Devonian formation, in Jefferson county, Ky., and in Clark county, lnd.

Platyostoma turbinata. HALL.

Plate XXI., figures 5 and 6.

Platyostoma turbinata, Hall. Fourteenth Rep. N. Y. St. Cab.— 1861.
Plaiyostoma turbinata, Hall. Illust of Dev. Foss., pi. 10—1876.
Plattjosloma turbinata, Hall. Pal. N. Y., Vol. 5, part 2, p. 27—1879.

Shell sub-turbinate, sometimes approaching a sub-globose form. Spire de-
pressed, or more or less elevated above the outer volution, sometimes nearly
on the same plane ; volutions three or four rapidly expanding, the last ex-
tremely ventricose, with the lower part projected in the direction of the col-
umella, which is much extended. Aperture sub-ovate, broader above, narrow-
ing, and often extended below.

Surface marked by fine, sub-equal concentric striae, crossed by finer revolv-
ing striae; the former variously undulated upon the surface, indicating
sinuosity in the lip of the aperture at former stages of growth. In older
shells the striae become lamellose and often crowded in fascicles.

Formation and Locality.— In the Corniferpus group around the Falls of UIQ Qhio, in Kentucky
and Indiana.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 185

Platyostoma turbinata, var. cochleata. HALL.

Platyostoma hirbinata, var. cochhata, Hall. Illust. of Devonian Fossils, Caster., pi. 10 — 187G.
Platyostoma turbinata, var. cochleata, Hall. Pal. N. Y , Vol. 6, part 2, p. 28—1879.

Shell turbinate. Spire elevated, conical ; volutions about four or five ; per-
iphery of the last volution obtusely rounded or distinctly sub-angular, with
a sinus in the margin of the aperture ; the last volution sometimes becoming
free near the aperture, which latter is obliquely sub-ovate or ovate ; peristome
sinuous, often with a deep notch in the upper margin, and sometimes con-
tinued in a columellar extension below.

The specimens referred to this variety all agree in having an elevated spire,
with rounded volutions above the last one, which is almost invariably sub-
angular.

Formation and Locality. — Found associated with Plat, lineala in the rotten hornstone of the Devo-
nian formation around Louisville, Ky.

Platyostoma niagarense. HALL.

Plate XXXIII., figure 30.

Platyostoma niagarenm, Hall. Pal. N. Y., Vol. 2, p. 287, pi. 60, figs, la-lv— 1852.
Platyostoma niagarense, Hall. 28th Rep. N. Y. St. Mus. Nat. Hist., Mus. edit., p. 175, pi. 28, figs. 1-12; pi.

29, figs. 1-15—1879.
Platyostoma niagarnwe, Hall. Ind. Geo. Survey, llth Rep., pi. 29, p. 318—1881.

The following description is quoted from Prof. Hall : Shell ovoid or sub-
globose ; volutions three to four, the last one very ventricose ; spire varying
from the plane of the outer volution to an elevation of one-fifth or one-fourth
the height of the shell above.

Apex minute, somewhat rapidly expanding, the first two volutions usually
symmetrical ; the outer volution often unsymmetrical, very ventricose and
regularly rounded upon the back, but not unfrequently extended and becoming
free towards the aperture, and marked on the upper or lower side, or upon
both, by a groove, along which .the striae are abruptly bent, indicating a sinus
in the peristome during some period of its growth ; peristome entire or undu-
lated, sometimes distinctly notched in the margin, free or adhering on the
columellar side, and sometimes expanded and presenting a thickened callosity
or oolumellar lip.

Surface marked by fine undulating striae of growth, which sometimes become
lamellose. In well preserved specimens, finer revolving striae cancellate the
striae of growth, and sometimes the surface is marked by revolving ridges.

Formation and Locality. — Occurs in the Niagara near Louisville, Kentucky. The specimen
figured is a, very young one.
OEOL. SUK. — 24

186 PALEONTOLOGY OF KENTUCKY.

Genus Strophostylus.

Strophostylus, Hall. Pal. N. Y., Vol. 3, page 303—1859.
Etymology : strophe, turning around ; stylos, a column.

Shell sub-globose or ovoid-globose ; spire small, with a large ventricose
body-whorl. Outer lip thin, not reflected, sometimes slightly expanded.

Columella twisted or spirally grooved within ; not reflected. No umbilicus.
Aperture somewhat round-ovate or transversely broad oval.

Strophostylus varians. .HALL.

Plate XXII., figures 6 and 7.

Strophostylus varians, Hall. 111. of Dev. Foss., pi. 2 — 1876.
Strophostylus varians, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 31—1879.

Shell of medium size, spiral, with moderately elevated spire; volutions
about three or four; ventricose and regularly rounded above, and somewhat
rapidly increasing, the last one becoming very ventricose, and extending
downward and forward. Aperture ovate or sub orbicular ; peristome entire ;
the columellar lip usually expanded, and spreading over the umbilicus, some-
times free, and leaving the umbilicus exposed.

Surface covered by fine, closely set, transverse striae, the suture, owing to
the great convexity of the volutions, deep and well exposed. Prof. Hall
makes the following remarks about this species: u This species, in some re-
spects, makes a wider departure from the typical forms of Strophostylus than
any other of the genus known to me. The peculiar and characteristic form is
preserved ; the symmetrical rounding of the volutions above, and the delicately
formed spire, as well as the form of the aperture in some specimens, are all
characteristic of the genus. The striae, however, have a tendency to become
lamellose or interruptedly undulating ; and there are evidences of irregularity
of growth and indentations in the margin of the peristome, both above and
below the periphery. The form of the aperture is extremely variable, from
narrow elliptical to broadly expanded. There is, though rarely, a tendency in
the last volution to become free, and the characteristic plication of the colum-
ellar lip is not often well preserved. In some of its variations it simulates
Platyostoma, but in all phases it differs from that genus in the characteristic
expression of the spire."

Formation and Locality.— Occurs in the Corniferous limestone at and around the Palls of the Ohio
in Kentucky and Indiana; but it is a rather rare shell in our rocks.

FOSSILS Otf THE SILURIAN AND DEVONIAN ROCKS. 187

Genus Cyclonema, Han.

Cyclonema, Hall. Pal. K Y., Vol. 2—1852.
Etymology: kuklos, a circle; nema, a thread.

Shells turbinate, thin; spire short, consisting of few volutions, which in-
crease rapidly from the apex ; aperture large, rounded anteriorly, and some-
what flattened on the columella side ; umbilicus none ; surface strongly
marked by spiral, thread-like striae, which are cancellated by finer striae.

This genus includes shells which have been referred to Pleurotomaria, Litto-
rina and others, but which have no slit or indentation in the outer lip or a
band upon the volutions.

The surface is marked by elevated striae parallel to the direction of the
volutions, and the spaces between these are marked by finer striae crossing the
others obliquely ; tliese latter, however, are often obsolete.

The Pleurotomaria bilix of Conrad is the type of this genus.

Cyclonema cancellata. HALL.

Plate XX., figures 10 and 11.

Littorina cancellata, Hall. Geol. Kep. 4th Dist. N. Y. — 1843.
Cyclonema cancellata, Hall. Pal. N. Y., Vol. 2, page 90 — 1852.

Obtusely sub-conical or globose, with a short spire ; volutions about four,
rounded, rapidly increasing from the apex, so that the last one occupies
almost the whole bulk of the shell ; aperture scarcely expanded.

Surface marked by prominent thread-like lines, coincident with the spire,
which are decussated by finer elevated striae in a slightly oblique direction.

The size of this shell varies greatly, from one measuring only a few lines to
the size shown in the illustrations. In .young individuals, the decussating
striae are usually well preserved, while they gradually become obsolete in older
specimens, which are also often distorted by pressure.

Formation and Locality.— Occurs in the lower strata of the Niagara group in the quarries east of
the city of Louisville, where, however, it is a very rare shell. The specimen from which this description,
and the figures 10 and 11, on plate 20, were made, belonged to the collection of the late Dr. James Knapp;
no others are known to me.

Gyclonema rugaelineata. HALL AND WHITFIBLD.

Plate XXXIII., figure 21.

Euomphalus (Cyclonema) rugaelineata, H. and W. 24th Rep. on N. Y. State Cabinet, p. 186—1872.
Euomphulus (Cyclonema) rugaelineata, H. and W. 27th Rep. on N. Y. State Cabinet, pi. 13 — 1875.

Shell of medium size, depressed turbinate, with four or five volutions, which
increase very rapidly ; they are rounded, very convex, and the last one is very

188 PALEONTOLOGY OF KENTUCKY.

ventricose. The surface is ornamented by ten to twelve strong, sharply ele-
vated, revolving lines, having a smaller one between them. On the upper half
of the body-whorl the stronger revolving lines have larger interspaces than
those on the lower half, but the lines in the interspaces are smaller above the
center of the volution than those below it. Between suture and the upper
carina or strong revolving line, there are four very fine revolving lines, only
indicated by the four rows of imbrications, which are there conspicuously
marked. These revolving striae are crossed transversely by irregular lamellose
lines of growth, to which the surface owes its finely .ornamented, somewhat
rugose appearance.

Suture, owing to the great convexity of the volutions in their cross-sections,
deep and sharply marked.

Apex and the first one or two volutions not known on account of the decol-
lated condition of the shell. Aperture supposed to be round ; form of base
and columella unknown.

Prof. Hall states that this species bears considerable resemblance to Euom-
phalus carinatus of Sowerby, found in Europe in the Niagara group, from
which it differs by the smaller number of revolving carinae, and in the posses-
sion of the intermediate lines, as also in the character of the transverse
striae.

Formation and Locality. — In the Niagara strata of the different quarries east of the city of Louis-
ville, Ky. My illustration of this shell is a copy of Prof. Hall's, who made his from a not very good speci-
men in Dr. James Knapp's collection. That specimen was, for some time, the only one known ; but since
then I have found several myself. One of my shells is not at all distorted, showing three volutions in their
regular form, and with their surface ornamentation, except the markings on the lower half of the last
volution.

Cyclonema multilira. HALL.

Plate XXII., figure 5.

Cychnema multilira, Hall. Descr. NewiSp. of Fossils, p. 20 — 1861.

Ct/donema multilira, Hall. Fiteenth Rep. N. Y. State Cab. Nat. Hist., p. 48—1862.

Ci/cJojiema multilira, Hall. Illustrations of Devonian Fossils, Gasteropoda, pi. 12—1876.

Cyclonemu mullWra, Hall. Pal. N. Y., Vol. 5, pt. 2, pi. 12—1879.

Shell medium size, pyramidal in outline, gently turbinate, with four increas-
ing volutions; suture line indistinct. On the surface of the volutions are
regular, prominent plications, and very broad sinuous furrows, winding par-
allel to the suture- line. Volutions begin sharply, but increase in diameter,
and become a little more ventricose.

The description is based upon a very imperfect cast, in which the lip and
umbilicus are wanting.

Formation and Locality.— From the lower Devonian near Louisville, Ky.

FOSSILS OF THE SILURIAN ANI> DEVONIAN ROCKS. 189

Genus Trochonema. saitor.

Etymology : trochos, a wheel ; nema, a thread.

This genus is never defined by any writer in this country. It includes spiral
shells, having some relations to Pleurotpmaria, but differing from that genus
by exterior characters.

Trochonema fatua. HALL.

Trochonema fatua, Hall. 20th Reg. Rep., page 345—1867.

Spire elevated ; shell turritiform, consisting of about four or five volutions,
which gradually increase to the last one, which is moderately ventricose ; volu-
tions biangular, leaving a flattened space upon the back about equal to flattened
space between upper angle and suture line ; lower half of last volution
rounded ; aperture ovate-elongate. The specimens from which this descrip-
tion was made by Prof. Hall were casts, and so is the one before me, which
answers in every particular the above description. Prof. Hall states that the
surface of the shell, as seen in an imprint in the rock, is finely striated, and
that the flattened space on the back of volution is margined on each side by a
slender carina, and is covered by coarser striae.

The size of different specimens varies greatly ; its height is from one to one
and seven-eighths of an inch, while the diameter of its base is about four-
fifths of its height.

Formation and Locality. — Found in the Niagara rocks, in the quarries east of the city of Louis-
ville, Ky. It is very rare; the only specimen known to me belongs to the collection of Major "Win. J.
Davis, of Louisville, Ky.

Trochonema rectilatera. HALL.

Plate XX., figures 1 and 2.

Trochonema redilatera, Hall. 24th Regent's Rep., p. 193—1872.
Trochonema rectilatera, Hall. 27th Regent's Rep., pi. 13—1875.

Shell of medium size, turbinate ; breadth and height almost equal ; volution
about five, carinated above with straight, nearly vertical sides ; outer one ven-
tricose, with two carinae having a wide, vertical, slightly concave space be-
tween, which occupies more than one-third the height of the volution. Upper
side of the volutions convex for half the distance to the carina, and below this
they are concave, giving the form of an ogee.

In another specimen, apparently the upper [side of the volutions are slightly
concave, and regularly sloping downward from the suture to the carina. Lower
side of the volution not carinate ; umbilicus small, or closed with a callosity

190 PALEONTOLOGY OF KENTUCKY.

Surface marked by fine striae of growth, which are turned backward from
the suture, and are vertical on the sides of the volution, and on the lower side
curve backward to the umbilical area.

Formation and Locality. — In the upper strata of the Devonian limestone, at and around the Falls
of the Ohio, where it is exceedingly rare. As Dr. Knapp's collection, which contained the original speci-
mens, is sold, I don't think there exists a representative of this species in the Falls Cities.

Trochonema yandellana. HALLAND WHITFIELD.

Plate XX., figure 3.

Trochonema yanaellana, H. and W. 24th Regent's Rep., p. 194 — 1872.
Trochonema yandellana, H. and W. 27th Regent's Rep., pi. 13 — 1875.

Shell turbinate ; volutions about five (three of which are shown in the illus-
tration), rapidly increasing, carinated ; the last volution becoming ventricose,
and marked by seven revolving carinae, including the one bordering the some-
what channeled suture ; four of the carinae are distinctly marked by thin,
lanceolate nodes, which become more prominent with the increased growth of
the shell, while the other three — one bordering the suture and two on the lower
middle portion of the volution — are destitute of nodes in the specimen de-
scribed, but it may be that it assumes this character only in an advanced stage
of growth. The carinae are situated, one at the suture and one bordering the
moderately large umbilicus, with five on the body of the volution, of which
two are above the. middle and three below. The spaces separating those bor-
dering the suture and the umbilicus from those on the body of the volution,
are considerably wider than the .spaces between the intermediate carinae.
Aperture rounded, slightly modified by the carinae.

Surface marked by fine transverse striae of growth, which turn backward
as they cross the volution to the umbilicus.

The illustration on plate 20 is a copy of Prof. Hall's figure in the 27th Reg.
Rep., and this description also a copy of Prof. Hall's in the 24th Reg. Rep.
At the time when my plates were prepared there was only cne specimen of
this species known, which belonged to the .cabinet of the late Dr. James
Knapp, and which at that time was not accessible to me. Since then I came
myself in possession of a very fine specimen of this species, which differs some-
what from Knapp's. Instead of having only four carinae with nodes, as is the
case in Knapp's shell, mine has six. The only smooth carina in my specimen
is that bordering the suture. There is also a marked difference in the inter-
spaces between the carinae ; while in Knapp's shell the distance from the
carinae bordering the suture and the umbilicus, to their adjacent one, is larger
than the distances between the other carinae, in my specimen the interspaces
between the first carina, as which I count the one near the suture, and the

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 191

second, and between this and the third, are almost twice as wide as any of the
balance. Outside of these mentioned differences there is a complete resem
blance between the two specimens.

Formation and Locality.— Found in the cherty layers of the Corniferous limestone, at and around
the Falls of the Ohio, in Kentucky and Indiana. This beautiful fossil is exceedingly rare; as far as 1
know, Dr. Knapp's and my own specimen are the only representatives of this species. Prof. Hall, who first
described and illustrated this species from Dr. Knapp's shell, named it in honor of the late Dr. Lunstbrd
Yandell, ST., of Louisville, Ky., who was one of the first collectors of the fossils at and around the Falls of
the Ohio.

Genus Turbo, xiem.

Turbo, Klein. Tent. Meth. Ostr.— 1753.
Etymology: turbo, meaning a top.

Type of this genus is Turbo marmoratus.

Shells turbinated, solid ; whorls convex, often grooved or tuberculated ; aper-
ture large, rounded, slightly produced in front ; operculum shelly and solid,
callous outside, and smooth, or variously grooved and mammillated ; internally
horny and pauci-spiral.

This genus extends from the Silurian to the present time.

Turbo Shlimardi. De VERNEUIL.

Plate XIX., figures 1 to 4, and Plate XXII., figures 1 and 2.
Turbo shuniardi. De Verneuil. Bulletin de la Soc. Geol. de France.

Shell large, gibbous, sub-globose. Spire moderately elevated ; apex minute •
volutions about five or six, gradually enlarging in the earlier stages of growth,
while the last one increases in size very rapidly, and becomes very ventricose
with an expanded aperture. ' The first two or three volutions are smooth and
regularly rounded upon the exposed surfaces, gradually becoming nodose and
flattened, or somewhat concave, on the upper or front side. The nodes increase
in size and strength with the increase of the volutions. Suture close in the
earlier volutions and becoming somewhat canaliculate in the later ones. Lower
side of the outer volution very convex, even in the umbilical region, and much
extended in the direction of the columella. Aperture broadly rounded ; col-
umellar lip obtuse, thickened, having a distinct broad opercular groove ; callus
covering the umbilicus and spreading outwardly ; external margin of the
aperture thin.

Surface marked by fine, comparatively even striae of growth, which are often
crowded into fascicles, and in old shells are somewhat imbricated at irregular
intervals.

The periphery of the outer volution is marked by a strongly elevated, ob-

192 AL^ONTOLOGY OF KENTUCKY.

tusely angular carina, which is continued from the suture-line at the inner
posterior angle of the aperture. The outer one or two of the volutions (de-
pending on the size of the shell) are marked or ornamented by strong curving
nodes, which, commencing just below the suture, are nearly vertical for a short
distance, and then curving forward, are finally directed towards the aperture,
and gradually become merged into the general surface.

The striae, originating at the suture, are first directed backward, and thence,
gently curving over the nodes, become nearly vertical, and thus continue to
near the peripheral carina, where they are turned a little backward, and, pass-
ing this elevation, they are directed with a light curve towards the coin-
mella.

This species possesses all the features of the Linnaean genus Turbo, to which
it was originally referred by M. de Verneuil, who described and named it in
honor of the late Prof. B. F. Shumard, of St. Louis. It is so very different
from all other shells of our rocks, that it will be recognized at the first glance
by any one, who has ever seen a correct illustration of it. The shell is usually
silicified, and is rarely well preserved or occurs as internal casts, which bear
only slight indications of the nodes, but none of the other surface-ornamenta-
tions.

Prof. Hall made his descriptions and illustrations from fine specimens be-
longing to the cabinet of the late Dr. James Knapp. One of Knapp's speci-
mens was also used for my illustrations, sub-figures 1, 2 and 3, plate 19. The
individual, of which figure 4, plate 19, and figure 2, plate 22, are copies, is in
my own collection, presented to me by Miss Spangler, of Clark county, Indi-
ana.

Formation and Locality — Found in the rotten hornstone of the Devonian formation in Jefferson
county, Ky., and in Clark county, Ind. It is not a very rare species, although specimens like Dr. Knapp's
and my own are extremely rare.

MOLLUSCA.

CEPHALOPODA.
Genus Gomphoceras.

Etymology : gomphos, a club; keras, a horn.

Gomphoceras oviforme. HALL.

Plate XXI., figures 17 and 18.

Gomph. oviforme, Hall. Thirteenth Kep. N. Y. St. Cab., p. 105—1860.
Oomph, oviforme, Hall. lilust. of Dev. Foss., Cephal., pi. 45 — 1876.
Cyrtoceras gibbosus, Hall. Illust. of Dev. Foss., Cephal., pi. 47 — 1876.
Oomph, oviforme, Hall. Pal. N. Y., Vol. 6, part 2, p. 344—1879.

Shell small, ovoid, sub-cylindrical, straight ; transverse section elliptical or
sub-circular ; longitudinal section sub-quadrate or sub-ovate. Plan of greatest
transverse section at the bottom of the body-chamber. The specimens of this
species found in our rocks have retained only a small section of the septate
portion of the shell ; usually only one or two septae are preserved. Apex is
truncated, apical angle about sixty degrees. Chamber of habitation compar-
atively large ; its length is about equal to three-fourths of its largest diameter ;
aperture large and trilobate (the one shown in figure 18, plate 21, is incorrect,
it is too narrow, and the third lobe, branching from the middle to the right, is
not at all illustrated, owing to the faulty condition of the shell which served
for illustration). Siphuncle near the ventral side, with a diameter of two mil-
limeters at the last septum. Test strong, having a thickness of one and a half
millimeters over the chamber of habitation.

Our specimens do not show any surface-markings ; if any existed on perfect
and well-preserved individuals, they are obliterated on ours by the process of
silicification and by exfoliation. Our shells being internal casts, the suture -
lines are plainly shown. The specimen illustrated in figures 17 and 18, plate
21, is of average size of those here found. This species is easily distinguished
by its cylindrical form, and by the trilobate shape of its aperture.

Formation and Locality. — Found associated with its congener, Gomph. turbiniforme, in the chert
topping the hydraulic limestone of the Devonian formation, in Jefferson county, Ky., and Clark county,
Ind., where it is somewhat abundant, but not in fair specimen.
GKOI.. SUR.— 25

J94 PALAEONTOLOGY OF KENTUCKY.

Goinphoceras turbiniforme. MEEK AND WORTHEN.

Plate XXI., figures 15 and 1C.

Gomph. turbiniforme, M. and W. Proc. Acad. Nat. Sci. Phil. — 1860.
Goynph. turbiniforme, M. and W. Geol. Kop. of 111., Vol. 3, p. 444—1868.

Shell rather small, turbinate or obovate, very slightly unsymmetrical ; sec-
tion circular, or nearly so ; chambered part rapidly expanding, with sides
slightly convex above. Non -septate part very short, or three times as wide as
long, rounding in abruptly, above ; aperture contracted, but exact form un-
known. Septa only moderately concave, nearly equidistant at all points,
except near the outer chamber and the apex, where they are more crowded ;
at about the widest part of the shell, separated by spaces equalling one-eighth
its greatest diameter. Siphon small and marginal. Surface nearly smooth, or
with only fine lines of growth.

This description is copied from 111. Geol. Rep., Vol. 3, page 444. The speci-
men there described and figured on plate 12, figures 2a, b, came from the
neighborhood of the Palls of the Ohio. The specimens figured on my plate,
21, are of the average size.

Formation and Locality. — FOUR — »ue cherty layers superimposed upon the hydraulic limestone
of the Devonian formation, in Jefferson, county, Ky., and in Clark county, Ind.

Genus Goniatites, DeHaan.

Etymology ; yonia, an angle ; lithos, a stone.

Goniatites discoidetis. HALL.

Plate XX., figures 14 and 15.

Goniatites discoideus, Hall 13th Rep. N. Y. St. Cab.— 1860.
Goniatites discoideus, Hall. 27th Rep. N. Y. St. Cab.— 1875.
Goniatites discoideus, Hall, lllust. Dev. Foss., pi. 71 — 1876.
Goniatites simiosus, Hall. Rep. 4th Dist. N. Y., p. 246—1843.
Goniatites discoideus, Hall. Pal. N. Y., Vol. 5, pt. 2, p. 441—1885.

Shell depressed orbicular in the young state, becoming discoid in its advanc-
ing growth. It differs in size, and in the proportion of its dimensions, accord-
ing to its age.

The specimen illustrated shows the average size of shells found in our
rocks.

A minute description can only be given by a geologist who has a large
number of specimens before him, some of which he may break or cut up, in
order to see the number of volutions, which are all inside of the last one, or to

FOSSILS OF THE SILURIAN AND DEVONIAN ROOKS. 195

examine other internal features. The outside appearance of the shell offers
few points for description which the illustration does not plainly show.

Formation and Locality.— Found in the Corniferous limestone of the Devonian formation, at and
around the Falls of the Ohio, in Kentucky and Indiana.

Genus Lituites.

Etymology : leiuus, a trumpet.

Lituites marshi. HALF..

Plate XXX., figure 1.
Liiuiiea marshi , Hall. 20th Regent's Rep., p. 362—1867.

Shell of medium size, consisting of four or more closely enrolled volutions,
which increase in size gradually, but very slowly, from the apex ; transverse
or cross-section circular or sub-circular ; slightly flattened on the dorsum, and
marked on the sides by sharp, strong, oblique annulations, with regularly con
cave spaces between them. These ridges, rising on the ventral margin, are
directed obliquely backward as they cross the sides of the volutions, reaching
the center of the dorsum at a point opposite the origin of the second preceding
one, having their greatest elevation on the sides of the shell, and maJdng a
somewhat abrupt retrorse curve, become almost obsolete on the dorsum. Septa
moderately distant, deeply and regularly concave, the chambers regularly
increasing in depth with the diameter of the shell. The space of three cham-
bers, measured on the side of the shell, are equal to the dorso-ventral diameter
of the volution. The dorsal margins of the septa are directed forward, giving
a broad rectral curvature on the side of the volution. Siphuncle small and
sub-central.

Surface of shell and form of aperture are unknown. This beautiful species
is readily distinguished by its slender volutions, and the strong, oblique ridges,
which, in the outer part of the shell, are a little more distant than the septa,
while on the inner volutions they are nearer to each other, the increase in the
distance of the annulations being a little more rapid than that of the septa.
Owing to the retrorse curving of the annulations, and the advancing curvature
of the septa, the ridges are cut by the latter near the dorso-lateral angle of the
volution, throughout the greater part of the extent of shell.

In the specimen illustrated on plate 30, both termini of the shell are missing ;
it has preserved more than three complete volutions. The vacant central space
indicates that, probably, two full volutions are obliterated there at the apex.
How much there is destroyed at the other end can not be ascertained, but that

196 PALEONTOLOGY OF KENTUCKY.

there is a large part of a volution missing can not be doubted. Thus it
appears that the illustrated specimen, in its perfect condition, had six full
volutions. Prof. Hall named this species in honor of Prof. O. C. Marsh, the
eminent geologist.

Formation and Locality. — Found in tho N iagara rooks of the quarries east of the city of Louis-
ville, where fragments of this shell are not rare, but fair specimens are not often found.

NaUtilUS. Breymus.

Etymology : nautilos, a sailor or navigator.

Nautilus maximus. CONBAD.

Plate XXIV., figure 1.

Cyrtoceras maximum, Conrad. Geol. Survey of N. Y., Pal. Dept. First Ann. Rep. — 1838.
Nautilus maximus, Hall. Illust. Dev. Fossils — 1876.
Nautilus maximus, Hall. Pal. N. Y., Vol 6, pt. 2, p. 418—1876.

Shell very large, sub-discoid, gibbous, becoming very ventricose. Volutions
about three, contiguous, not re-entrant. Umbilicus wide and deep, exposing
all the volutions. Transverse section sub circular, flattened on the concave
dorsal side ; tube regularly and gradually enlarging to a point near the aper-
ture; apical angle about fourteen degrees. The body -whorl, or chamber of
habitation, very large and ventricose, occupying half a volution and more. In
the larger individuals it is free from the inner volution for about one-third its
length.

Length of the grand chamber more than twice its greatest diameter, gradu-
ally contracting towards the aperture from a point about two-thirds of its
entire length from the base. Aperture slightly oblique to the axis of the tube,
opening upward. Air-chambers numerous, regular and very deep, gradually
increasing from the apex, and measuring on the convex side sometimes more
than thirty millimeters ; the last one shallower than several of those pre-
ceding.

Septa regular, distant, very concave, the concavity greater than the depth
of the air-chambers ; strongly imbricating. The distance between the septa is
variable in different specimens, but in the same individual is nearly constant,
with a gradually increasing distance. Siphuncle large, sub-central, slightly
expanding between the septa.

The ventral side of the shell is indicated by a sharp, narrow, longitudinal
raised line on the outer face of the chambers, on the convex side of the volu-
tions. Test seldom preserved.

FOSSILS OP THE SILURIAN AND DEVONIAN ROCKS. 197

Surface marked by fine and coarser, irregular, lamellose lines of growth, and
fine, regular, undulating, elevated, thread-like striae, parallel to the lines of
growth ; longitudinally marked by rounded, or sometimes sharper, undulating,
revolving striae, of which there are five or six in the space of five millim-
eters.

These markings are visible on the macerated inner laminae of the shell, and
often even on the internal cast. The internal cast is strongly marked by the
suture-lines, which are deeply impressed from the solution and removal of the
imbricating margins of the septa.

The largest known specimen of this species has a diameter of 360 millimeters,
and the chamber of habitation of the same specimen, measured along the mid-
dle of the lateral face, has a length of more than 360 millimeters, and measured
on the periphery, has a length of more than 450 millimeters. This species
resembles N. oriens and magister, from both of which it is, however, easily
distinguished.

Formation and Locality. — Found in the hydraulic limestone of the Devonian formation at the
Falls of the Ohio, in Kentucky and Indiana. The figure on plate 24 is only one-half of the natural size
of the shell from which it was taken.

MOLLTJSCA.

LAMELLIBRANCHIATA.
Genus Limoptera. Han.

Limoptera, Hall. Prelim. Notice Lam. Shells — 1870.
Etymology : lima, a genus of shells; pteron, a wing.

Shell large, inequilateral, inequivalve ; the right valve the smaller ; ligamen-
tal area large, common to both valves ; longitudinally striate, and extending
to the extremities of the wings. Margins of valves sinuate on the anterior
border, forming an elongate byssal opening ; hinge edentulous (?). Anterior
muscular impression situated within the umbones, very small and deep ; the
posterior one large, and placed a little behind the middle of shell, and nearer
to the hinge than to base of valve. Pallial line simple, formed of a series of
small, deep pits (or, as seen in the casts, composed of a' series of small
nodes).

The general form of the shells, when well preserved, is broadly ovate or

198 PALEONTOLOGY OF KENTUCKY.

sub-quadrate in outline, strongly alate on the posterior side, and often more or
less produced on the anterior end. The valves are convex in all species known ;
the left valve being strongly convex throughout, while the opposite one is but
slightly elevated, and in one species is somewhat concave near the base. The
surface is coarsely radiate in all but one species. The ligamental area is large,
in both valves sub-equal, and without cartilage pits. Lima macroptera of
Conrad may be considered as type of this genus.

Limoptera cancellata. HALL.

Plate III., figures 6, 7 and 8; Plate IV., figure 24.
Limoptera cancellata, Hall. Prel. Nat. Lam. Shells, pt. 2 — 1869.
Limoptera cancellata, var. occidens, H. and W. 24th Reg. Rep., p. 199 — 1872.
Limoptera cancellata, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 244—1883.

Shell large ; body sub-erect ; general outline very variable, from broadly
ovate to sub-elliptical ; axis of the body nearly vertical to the hinge-line ; pro-
portion of height to length very variable ; sometimes both dimensions are nearly
equal, but mostly the height predominates over the length, and, as shown in
our illustration, in some shells to a considerable extent. The prevailing form
may be described as follows : Elongate oviform, almost erect, with a slight
anterior inclination ; plano-convex, with the left valve strongly convex in the
umbonal region, and only moderately convex, almost flattened, in its basal
half. The right valve is entirely flat, with only a gentle elevation in the
umbonal region. Height exceeding the length ; their proportion as four to
three.

The margins in the lower or basal half of the shell regularly curved ; in the
upper half, the anterior margin of the body is only slightly rounded, while
the posterior margin of the body forms an entire straight line.

The lateral slopes of the umbonal region are very steep, meeting the surface
of the wings almost at right-angles, forming thus a demarcation line for the
ears. The wings are unequal, the anterior considerably smaller than the
posterior. The front wing forms only a small triangular deflection of the
anterior margin, while the posterior wing has a considerable width on the
hinge-line, and in its longitudinal dimension extends below the middle of the
shell. The hinge-line is usually straight, but sometimes deflected in different
directions, as our illustration shows ; it is shorter than the height or length.
The umbo of the left valve is prominent, and the beak straight, rounded and
pointed, and overreaching a small triangular hinge-area, which has no fora-
men. The beak is situated about one-third the length of the cardinal line
from its anterior end, and has a decided anterior direction. In the right valve
the beak does not extend beyond the cardinal line. The posterior margin of

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 199

the rear wing is concave, but deflects back near the cardinal extremity, which
is angular.

Test is of moderate thickness, and is ornamented by rounded, abruptly
elevated radii, with large, flat interspaces, which are sometimes occupied by
one and even two finer, radiating striae ; but in some shells these finer striae
are obsolete. These radii are crossed, and the large interspaces cancellated by
fine concentric lines of growth. Towards the margins, in the basal half of
the shell, the radii become either entirely obsolete, or at least very obscure.
On the wings the radiating striae are also obsolete, but .the concentric lines of
growth are there more prominent and crowded. On the anterior slope of the
left umbo exists a curved line of small and low nodules, numbering from ten
to twelve or more. This line starts at the beak and extends about an inch
towards the front. These nodes indicate small pits in the interior surface of
the shell, and served, probably, as attachment for some muscles. The right
valve has a similar line of nodes. The specimen here described measures three
inches in height, two inches and one-fourth in length, and its hinge-line one
and three-quarters inches long.

Formation and Locality. — Occurs in the cherty layers superimposed upon the hydraulic limestone
of the Devonian formation, in Jefferson county, Ky., and in Clark county, Ind., where it is found as a
silicifled internal cast. Not rare.

Meek and Wortben.
Etymology : khno, I lean ; opisthe, backwards.

Clinopistha SUbnaSUta. HALL AND WHITFIELD.

Plate IV., figures 6, 7, 8 and 12.

Tellinomya subnasuta, H. and W. 24th Reg. Rep., p. 191—1872.
Dystactella (Tellinomya) subnasuta, H. and W. 27th Reg. Rep., pi. 2—1876. .

Shell small, elongate, sub-elliptical, twice as long as high, with very ventri-
cose valves, giving the shell in its middle part a sub-cylindrical appearance ;
posterior end very narrow, shorter than the anterior one, and pointed at the
extremity ; anterior end regularly rounded, longest above the center ; basal
line in its central half almost straight, sometimes a little inflected opposite the
beaks, or slightly convex ; Lits terminal parts turn in a gentle and regular
curve upwards to the anterior and posterior extremities ; beaks small and
closely appressed, situated at two-thirds of the length of shell from the an-
terior end. Muscular impressions of moderate size distinctly marked, situated
near the margin of valve ; pallial line entire, composed of a series of radiating
pustules, as seen on the cast.

200 PALEONTOLOGY OF KENTUCKY.

Surface marked by distinct, rather strong, somewhat lamellose lines of
growth. Prof. Hall expected that this species might not really belong to the
genus Tellinomya, and proposed for it the name of Dystactella, but placed it
afterwards with Clinopistha.

Formation and Locality. — In the chert beds overlying the hydraulic limestone in Jefferson county,
Ky., and in Clark county, Ind.

Clinopistha antiqua. MEEK.

Plate IV., figures 9, 10 and 11.

Clinopistha antiqua. Meek. Proc. Acad. Nat. Sci. Phil. — 1871.
Clinopistha antigua, Meek. Geol. of Ohio. Pal., Vol. 1, p, 208 — 1873.

Shell transversely sub-oval, regularly and moderately convex ; height two-
thirds of the length, and depth one-half of height ; anterior end regularly
rounded ; posterior extremity only one-half as high as the anterior one, nar-
rowly rounded, and most prominent below ; basal margin almost straight, or a
little inflated or slightly convex, and curving abruptly upwards at the ex-
tremities; beaks depressed nearly or quite to the dorsal outline, small and
closely appressed, and placed at five-eighths of the whole length of the shell
from its anterior end ; dorsal line near the beaks parallel with basal margin,
but curving regularly into the anterior margin.

Surface shows fine concentric lines of growth, but no other markings. The
specimen illustrated is of average size and form. I place this shell with
Meek's species, though my specimens are more elongate and less gibbous than
his.

Formation 'and Locality. — In the chert beds superimposed upon the hydraulic limestone of the De-
vonian formation, in Jefferson county, Ky., and Clark county, Ind.

Clinopistha striata. N. SP.

Plate IV., figures 1 and 2.

Shell of medium size, transversely sub-elliptical ; length not quite twice the
width or height, and thickness about one-half the height; beaks small and
closely appressed, in the level of dorsal margin, and situated about two-thirds
of the whole length from anterior extremity ; basal margin slightly convex in
its central half, but curving regularly but rapidly into the terminal margins.
Dorsal margin straight and almost parallel with the central portion of the
basal one ; at its anterior end it curves down into the anterior margin, which
appears to be regularly rounded ; posterior end slopes down from the beaks to
a somewhat pointed posterior extremity, which is most prominent a little below
middle height of the shell ; both valves are moderately convex,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 201

The surface is marked by very peculiar radii, which, apparently, run from
the basal margin to the dorsal one, across the valves, but which make, near the
dorsal line, a rapid deflection into the direction of the beaks. These radii are
low and flat, and have a faint, but plainly observable depressed line in their
middle, a feature which I have never noticed in any other shell. Their inter-
spaces are large, from three to four times of their own width ; in some of
these interspaces there is a smaller intermediate line. This species has the
general features as Clinopistha subnasuta and antiqua, except its peculiar sur-
face-markings, and its greater size. I place it into the genus Clinopistha, on
account of its general form agreeing with that of C. subnasuta ; whether or
not interior characters will leave it there or transfer it to another known
genus, or make a new one for its reception, I can not say. The two specimens
illustrated on plate 4 are of average size, and are, as far as I know, the only
two shells of this species so far found. Both belong to my own collection.

Formation and Locality.— Found in the cherty layers overlying tile hydraulic limestone of the
Devonian formation, in Jeflerson county, Ky., and in Clark county, Ind.

Genus Ptychodesma. Han.

Ptychodesma, Hall. 24th Regent's Report — 1872.
Etymology : ptychos, a folding ; desma, a ligament or band.

Shell modioloid in form ; valves equally convex ; hinge with a wide liga-
mental area, the sides of which are sharply grooved in parallel lines, caused
by the successive growth of the ligament, as in Pectunculus. The grooves and
ridges are slightly arched beneath the apex of the valves, where they take
their origin.

The internal hinge structure is unknown. In general form and characters
this genus resembles Modiomorpha, but differs in having a ligamental area
marked by fine striae parallel to the hinge-line, while this is parallel to the
margin of the shell.

The type of the genus is Ptychodesma knappiana.

Ptychodesma knappiana. HALL.

Plate II., figures 13, 15, 16, 17 and 18.

Ptychodesma knappiana, H. and "W. 24th Rep. N. Y. — 1872.
Ptychodesma knappiana, Hall. Pal. N. Y., Vol. 6, pt 1, p. 353—1885.

Shell of medium size, obliquely sub-ovate ; length usually more than one-
third greater than the height ; basal margin oblique, often nearly straight in
the middle of its length. Posterior end broadly rounded,

GEOL. SUR. — 26

202 PALAEONTOLOGY OF KENTUCKY.

Cardinal line straight, oblique, having a length posterior to the beaks of
about one-half the length of the shell. Anterior end very short, curving
downward into the basal margin without limitation. Valves convex in the
lower and posterior portions ; gibbous in the middle and above.

Beaks sub-anterior, small, distant, closely incurved, rising but little above
the hinge- line. Umbonal slope presenting an undefined ridge, which merges
into the general convexity of the shell about the middle of its length. Test
thick, marked by fine concentric striae, with distant imbricating lamellae.

Ligamental area deeply excavated, marked by numerous longitudinal striae,
which are abruptly arched just beneath the beak. Hinge with two or more
cardinal teeth. Anterior muscular impression strong.

Dimensions of the shells in this species do not vary much. Figure 16, plate
2, represents an individual of average size.

This shell bears some resemblance, externally, to some species of Modio-
morpha and Nyassa, but its deeply grooved ligamental area is a distinctive
feature. Figure 18, plate 2, shows the said area of a left valve once enlarged.

Formation and Locality. — In the cherty layers of the Devonian limestone, which Prof. Hall places
among the Hamilton rocks, in Clark county, Ind., and in Jefferson county, Ky. It is found in well pre-
served, silicified specimens, but is a rather rare species ; it is represented in only a few collections in the
Falls Cities and elsewhere. Prof. Hall named this species in honor of the lamented Dr. James Knapp, ot
Louisville, Ky., who collected the first specimens of it, and loaned them to Erof. Hall for description and
illustration.

Genus Conocardium. Bronn.

Conocardium, Bronn. Lethaea Geognostica, Vol. I., p. 92 — 1835.
Etymology : konos, a cone ; kardia, the heart.

Type : Cardium hybernicum, Sowerby.

Shell equivalve, inequilateral, more or less fusiform or trigonal. Posterior
end obliquely truncate, produced along the cardinal line into a siphonal tube,
and sometimes the antero-inferior margin is also produced. Anterior end
conical and gaping in front. Beaks prominent and strongly incurved. Ven-
tral margins crenulated ; cardinal line straight ; umbonal ridge prominent, and
ornamented with an expansion of the test in continuation of the truncated
posterior end.

Surface marked by concentric striae, and usually ornamented with strong
radii. Hinge with anterior and posterior laminar teeth. Ligament external ;
muscular impressions two in each valve, situated near the cardinal extremities ;
pallial line simple. In the anterior end there is a thickening or internal pro-
cess forming, apparently, a foot-sheath.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 203

Conocardium cuneus. CONRAD.

Plate V., figures 10 to 19.

Pleurorhynchus cuneus, Conrad. Geol. Surv. N. Y. Ann. Hep. — 1840.
Pleurorhynchus trigonalis, Hall. Geol. Surv. N. Y. Rep. 4th Dist., p. 171 — 1843.
Conocardium trigonale, Hall. Pal. N. Y., Vol. 5, pt. 1, pis. and exp. — 1883.
Conocardium cuneus, Hall. Pal. N, Y., Vol. 5, pt. 1, page 409 — 1884.

Shell large ; shape very difficult to compare with any generally known form ;
its side-view is more or less sub-trigonal, and its dorsal or ventral view angu-
larly sub-ovate. The proportion of its length to its height varies considerably ;
the length is always greater than the height, but never becomes twice as large
as the latter.

The basal margin is gently curved from the posterior extremity to the an-
terior end. The posterior extremity is abruptly truncated, and produced into
a tubular extension alone: the cardinal line. This tubular extension attains,
in some shells, a considerable length, and is supposed to serve as a siphuncle.
The truncated rear end is very large in extent, and cardiform in shape ; it is
usually concave, with the exception of the part near and around the siphuncle,
which is more or less convex.

Cardinal line straight ; its margins, anterior to the beaks, are inflected. An-
terior end more or less rapidly contracting, with the margins gaping before
reaching the extremity. Valves entirely equal, and more or less gibbous. The
beaks are prominent and closely incurved over the hinge-line; they are situated
near the center.

The umbonal ridge is acutely angular, forming the line of demarcation be-
tween the lateral and posterior surfaces ; it extends from the beaks to the pos-
terior extremity in basal margin. Test thick, composed of two distinct
layers.

Surface marked by numerous radiating plications, and intermediate arching
lamellose, concentric striae on the body of the shell. The posterior surface
is ornamented by regularly curving radii, circling around the base of the
siphuncle. From the entire periphery of the umbonal ridge extends an ex-
pansion of the shell, called the shield, increasing in extent from the beaks
downward to the posterior extremity of the basal margin. This shield is
covered with fine striae, running parallel with the basal margin. In some
specimens, we notice at the extreme rear end of the body of the shell, where
the shield has been removed, a long, slender, cylindrical tube in the extension
of the basal line. What purpose it serves is not known. The valves are
finely crenulated at the margins. Prof. Hall has united different forms, which
were heretofore considered different species, into Con. cuneus ; he retains the
abandoned species, however, as varieties, which are as follows :

204 PALAEONTOLOGY OF KENTUCKY.

Var. uttenuatum, Conrad, which are apparently only the young of C.
cuneus.

Var. trigonale, the forms found in our rocks, and formerly always known
under that name.

Var. nasutum, Hall, a short, very ventricose, and abruptly truncated form.

Formation and Locality. — This shell is not rare in our Devonian rocks, at and around the Falls ot
the Ohio, where it is often found in the rotten hornstone; but fair or perfect shells are not often met with.
1 have figured on plate 5 a small individual which comes as near perfection as possible; it shows the
whole shell with complete shield, and is a most beautiful but delicate fossil. I found it on the Indiana
shore of the Ohio, opposite the falls.

Genus Cypricardinia. Han.

Cypricardinia, Hall. Pal. N. Y., Vol. 3, page 266—1859.
Etymology • Resembling Cypricardia.

Shell being inequilateral, with a more or less distinctly defined oblique pos-
terior ridge, the umbones anterior or sub-anterior, and little elevated. The
surface is concentrically grooved, or more or less distinctly marked by promi-
nent ridges or imbricating lamellae, and, on some of them, these lamellae are
radiatingly striated or cancellated.

A single well-preserved specimen shows no external ligamental area. In
some species the posterio-cardinal margin becomes alate or sub-alate. They
bear some general resemblance to Modiolopsis, but the shell is apparently
thicker, and is more strongly marked by concentric striae, and with a less
conspicuous anterior muscular prominence, while the aspect and general ex-
pression of the shells are quite distinct.

Cypricardinia cataracta. CONRAD.

Plate IV., figure 3.

The illustration of this species was made from the only specimen which I
then possessed ; that shell was defective in several places of its margins, in
consequence of which the figure does not show the exact shape or form of the
perfect shell. I shall try to correct this in my description.

Shell of medium size, sub-rhomboid-ovate ; length one-half greater than
height ; basal margin nearly straight, slightly concave anterior to the middle.
Posterior extremity abruptly rounded below, and obliquely truncate above.
Cardinal line straight, oblique. Anterior end very short, rounded below. Both
valves about equally convex; the right one, apparently, little more than the
left. The left valve is somewhat compressed in its middle portion near the
basal margin, but it becomes very convex, almost gibbous, in its umbonal
region.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 205

Beaks nearly anterior, of moderate size, and somewhat elevated above the
hinge-line; both incurved, and the right one below the other. The umbonal
ridge extends from the beaks to the produced lower part of the posterior ex-
tremity. It is most convex at about the middle of the shell, from where it
slopes in a gentle curve to its posterior extremity ; towards the hinge it in-
creases in gibbosity. On its dorsal side the umbonal ridge has a sharp, angular
limitation, separating what may be called the dorsal incline from the lateral
area of the valves. This umbonal line is acute- angular, and runs be.ow the
summit of the ridge, on its dorsal side, up to the middle of shell to the point of
greatest convexity ; from here it occupies the summit and becomes more or less
rounded, losing its distinction entirely on the posterior third of the shell.
The dorsal incline is strongly inflected at and near the beaks, but becomes
convex for the balance of its extent. On the basal side of the umbonal ridge
there is a shallow, broad depression, extending from the beaks obliquely across
the valves to the middle of basal margin ; this concavity is more pronounced
on the left valve than on the right.

The cardinal line is straight, and measures about two-thirds the length of the
shell. The surface is marked by several strong concentric lines of growth.
This shell resembles C. indenta, but differs from it by its shape and surface-
markings.

Formation and Locality. — Found in the Corniferous limestone at the Falls of the Ohio, on the
Indiana shore.

Cypricardinia cylindrica. HALL AND WHITFIELD.

Plate IV., figures 13, 14 and 15.

Cypricardinia cylindrica, H. and W. 24th Reg. Rep., p. 190—1872.
Cypricardinia cylindrica, H. and W. 27th Reg. Rep., pi. 11 — 1875.

Shell rather small, cylindrical ; extremities rounded ; height little more than
the depth, and rather more than twice as long as high ; beaks nearly ter-
minal, rounded and incurved ; left valve scarcely less convex than the oppo-
site ; umbonal slope slightly angular. Surface marked by faint, distant,
concentric, lamellose lines of growth.

This species is more elongate and cylindrical, less arcuate, and more equi-
valve than C. intiata. The lamellose striae have never been so strong, and are
more distant.

Formation and Locality — Occurs in the cherty layers superimposed upon the hydraulic limestone
of the Devonian formation in Jeffersen 'county, Ky., and in Clark county, Ind. It is a very rare shell, is
always silicified, and there are only very few specimens of this species known.

206 PALEONTOLOGY OF KENTUCKY.

Cypricardinia inflata, var. subequivalvis. HALL AND

Cypricardinia inflata, var. subequivalvis, H. and W. 24th Regent's Report, p. 189 — 1872.
Cypricardinia inflata, var. subequivalvis, H. and W. 27th Regent's Report, pi. 11 — 1875.

This species is described by Prof. Hall from a single specimen belonging to
the cabinet of the late Dr. James Knapp. At the time my plates were pre-
pared, said specimen was missing, and as thus the species was not represented
by any known specimen, I omitted it. Since then I have found, myself, two
fair shells of this species, and I therefore give here its description.

Shell small, nearly equivalve, sub-quadrilateral ; beaks terminal ; cardinal
and basal margins sub -parallel; left valve slightly smaller, less convex, and
straighter than the opposite ; the post-umbonal slope distinctly angular, while
on the right valve it is sub-angular or rounded.

Surface marked by about twelve to fourteen or sixteen strong, equal, lamel-
lose, concentric ridges. Prof. Hall based its name of equivalvis upon the fact
that in crushed specimens both valves appear equal, while good, not distorted,
individuals show the slight inequality of valves characterizing the genus.

This shell resembles C. inflata, Conrad, but the valves are more nearly equal,
and the right valve is less inflated.

Formation and Locality. — The chert beds overlying the hydraulic cement rock of the Devonian
formation, in Jefferson county, Ky., and in Clark county, Ind.

Genus Cypricardites.

Conrad.

Cypricardites, Conrad. Ann. Geol. Rep. N. Y. — 1841.
Etymology : resembling the Ejenus Cypricardia.

Shells ventricose, sub-orbicular or broad ovate in outline, with an external
flattened ligamental area ; cardinal teeth, four or five, short, oblique ; lateral
teeth, two or more, oblique; muscular impressions prominent, anterior one
single ; pallial line simple. Silurian.

Synonyms: Cyrtodonta and Vanuxemia of Billings, and Palaearca of
Hall.

Cypricardites halli. N.SP.

Plate XX XIV., figures 1 to 6.

Shell of medium size ; sub-triangular ; from moderately ventricose to gib-
bous ; both valves equally convex. Dorsal line almost straight, rounding at
its extremity into the anterior and posterior margins ; anterior margin slopes
down and backwards in a gentle curve, which is slightly inflected, at its center,
to the basal margin. The angle formed by the average direction of the an-
terior margin with the dorsal or hinge-line, measures about sixty degrees.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 207

The posterior margin slopes down from the hinge-line, either at right-angles,
or deflecting backwards, and forms a gentle curve ; the basal line is very short,
and strongly curved, forming almost a linguiforra extension of the shell ; its
most prominent point is either entirely posterior, or below the center of the
posterior portion of the hinge-line.

Both valves have their maximum convexity a little above the middle of the
shell, from where they slope in a regular curve, which is more or less strong,
according to the greater or smaller gibbosity of the shell, towards the sides
and front ; the slope on the posterior side of the umbonal region appears to
be somewhat steeper than the anterior, causing the flattening of the shell along
the upper half of the posterior margin, and especially at the posterior cardinal
angle. The umbonal region extends from the beak to the base, and crosses the
valves in a somewhat diagonal direction, terminating at the basal extremity.
The umbones are markedly deflected towards the anterior end ; they are only
moderately elevated above the hinge-line; the beaks small and closely incurved;
the hinge is nearer to the anterior end, at about two-fifths of the whole length
from the front. The size of the species is shown by the two specimens illus-
trated on plate 34, of which one is only moderately ventricose, while the other
is very gibbous.

The surface is marked by closely set, strong, concentric lines of growth,
which are more conspicuous near the margins than on the umbo.

Formation and Locality. — Found by me in the Hudson River shales of Oldham county, Ky.
Outside of the two specimens belonging to my own collection, I do not know of any others. To contribute
my mite, small as it may be, to the many well deserved honors of America's greatest geologist and palaeon-
tologist, the venerable Prof. James Hall, of Albany, New York, I have selected his name for this beautiful
little shell.

Genus Grammysia. Devemeun.

Qrammysia, De Verneuil. Bull. Soc. Geol. France — 1847.

Etymology : gramme, a line of writing; mys, a mussel shell; in allusion to the transverse furrows which
cross the valves from the umbones to the middle of the ventral margin.

Shells equi valve, inequilateral, not gaping, furnished with two muscular im-
pressions of very unequal size; pallial line rounded posteriorly, and united with
the large muscular impression in such a manner as to leave about two-thirds of
it outside of the line ; ligament external, much prolonged in the depression of
the escutcheon.

Surface traversed by an oblique fold or rib extending from the beak to mid-
dle of the inferior border, and by numerous rounded concentric folds. This is
De Verneuil' s description, which is improved upon by Prof. Hall's, which is as
follows : Shell equivalve, inequilateral, varying from sub quadrate to trans-

208 PALEONTOLOGY OF KENTUCKY.

versely elliptical. Valves ventricose, sometimes inflated ; beaks strong, prom-
inent and incurved ; hinge-line shorter than the shell, posterior to the beaks.
Dentition obscure, or represented only by irregular folds on the cardinal line ;
ligament external, prominent, extending from beneath the beaks to nearly
one-half the length of the hinge-line. Cardinal margin bordered by a small,
deep and strongly defined lunule. Anterior and posterior muscular impres-
sions faintly marked, the latter much the larger ; pallial line not sinuate but
broken into points or ridges, strongly rounded posteriorly, and uniting with
the large muscular scar near its anterior border.

Surface of shell often marked by an oblique mesial rib or fold, extending
from the beak to the basal border, and by numerous strong, concentric folds or
ridges, which are frequently obsolete on the posterior part of the shell. The
shells appear to have been thin and fragile, and are usually much crushed and
distorted from compression.

Grammysia gibbOSa. HALL AND WHITFIELD.

Plate IV., figures 16 to 20.

Qrammysia, secunda, var. gibbosa, H. and W. 24th Kep. on N. Y. St. Cabinet, p. 199 — 1872.
Qrammysia secunda, var. gibbosa, H. and W. 27th Rep. on N. Y. St. Cabinet, pi. 12 — 1875.

Shell of medium size, sub-elliptical. Proportion of length and height vari-
able, but the length always less than twice the height ; basal margin gently
curved, with a distinct but shallow sinuosity anterior to the middle, this incur-
vation of the basal border is often very obscure, and in some specimens
entirely obsolete. Posterior extremity is strongly rounded.

The cardinal line is straight, and measures about two-thirds of the length of
shell. Anterior end is short, and regularly rounded. Valves entirely equal,
moderately convex below and at the posterior end ; becoming gibbous in the
middle and above. Beaks almost anterior; of medium size and strongly in-
curved- and closely appressed. In some specimens the beaks of both valves
have different elevations above the hinge-line, one overlapping the other ; this
feature is not natural, but the result of some distortion. In perfect speci-
mens the beaks are of even height, and opposite to each other. The umbonal
slope is strongly rounded and extends to the posterior end of the basal margin.
A broad but very shallow depression extends from the beaks, crossing the
valves obliquely, and terminates at the basal sinus, forming a lateral sinus and
producing the basal one. In some specimens the lateral sinus is very obscure
and often entirely obsolete. The basal sinus is dependent upon the lateral
one; it is well marked, where the latter is plainly visible, and it becomes
obliterated, where the latter is obsolete.

Surface of the shells, which occur only as internal casts, is marked by

FOSSILS OP THE SILURIAN AND DEVONIAN ROCKS. 209

more or less strong, concentric folds or elevations, which are angular on the
anterior part of the shell, and become rounded and lower posteriorly. They
increase in size from the beak to the margins. In size this shell varies greatly ;
the forms illustrated give the average dimensions of this species.

Professors Hall and Whitlield consider it so closely allied to Grr. secunda,
as to make a variety of that species ; but to me, the differences between this
shell and the mentioned species appear so pronounced, that I place it in an en-
tirely different species, retaining Hall's name, "gibbosa."

Formation and Locality. — Occurs in the cherty layers topping the hydraulic limestone of the
Devonian formation, in Kentucky and Indiana, at and around the Falls of the Ohio.

Genus Paracyclas. Han.

Paracyelns, Hall. Geol. Surv. of N. Y., Kep. of 4th Dist.— 1843.
Etymology: para, allied to; cyclas, a genus of shells.
Type: Paracyclas elliptica.

Shell equivalve, sub-equilateral, sub-orbicular or broadly sub-elliptical. An-
terior end regularly rounded ; posterior end rounded or sub-truncate, some-
what more produced below than the anterior ; beaks small and low, generally
rising little above the hinge- line.

Hinge-line short ; post-cardinal slope more or less defined by an oblique
furrow or depression, which sometimes leaves the extremity sub-alate.

Surface concentrically striated; sometimes with strong concentric ridges
marking the exterior.

Structure of hinge not fully observed. Ligament supported on each side,
internally, by a narrow plate, and leaving in the cast two diverging grooves
directed forward from the beak. Muscular impression on the post-umbonal
slope. Pallial line parallel with, and a little within, the margin of the shell.

This fossil possesses many of the external characters of the finely striated
forms of modern Lucina ; and the distinguishing characters are not strongly
marked.

(Copied from Hall's Lamellibranchiata. )

Paracyclas elliptica. HALL.

Plate II., figures 1, 2 and 3.

Paracyclas elliptica, Hall. Palaeont. N. Y., Vol. 5, part 1, page 440, plate 72, figures 23 to 33.
Lucina elliptica, var. occidentalis, H. and W. 24th Ann. Rep. N. Y. St. Mus., page 189.

Shell large, sub-circular or broadly elliptical ; length and height about equal.
Pallial margin regularly curving from the extremities of the hinge. Cardinal
line short, more than one-third the length of shell, slightly arcuate.

GEOL. SUR. — 27

210 PALAEONTOLOGY OF KENTUCKY.

Valves regularly convex, somewhat regularly gibbous in the middle. Beaks
a little anterior to the middle, small, appressed, and closely incurved, rising
but little above the hinge-line. Umbonal slope denned above by a depression
extending from the beaks to about the middle of the posterior extremity, dis-
tinctly limiting the post-cardinal slope of the valves.

Test thin; surface marked by fine concentric striae, which are sometimes
aggregated into fascicles at irregular distances.

Ligamental groove narrow and elongate. Posterior muscular impression
just within the post-cardinal margin and below the ligamental groove. Pallia!
line parallel with the basal margin, marked in the cast by a row of elongated
nodes, which are the terminations of low ridges from above. Interpallial area
pustulose on the cast. (Hall.)

This species "resembles Lucina proavia of Goldfuss to such an extent that it
is impossible to distinguish the German species from the American. I have in
my possession a large number of perfectly preserved specimens of our shells,
and two equally well preserved specimens of Lucina proavia from the old
country, but so far none of my geological friends has been able to pick out
the foreign species.

Prof. Hall says the hinge of the German shell is much more declining, and
the anterior end is more elevated and sub-auriculate, as shown in Goldfuss'
figures. If such a difference is shown in the figures, which I do not doubt,
it may be that they were taken from a peculiarly formed specimen which did
not represent the average form of the species, or the figure may not be a cor-
rect copy of the specimen from which it was taken. Small differences, as
those marked out by Prof. Hall, taken from figures, should always be con-
sidered doubtful, and never used without other evidences to establish a new
species. I have not the least doubt that, in the course of time, the identity
of P. elliptica and L. proavia, will be acknowledged by all American geolo-
gists, and the fossil will then be known under the name of Paracyclas proavia.
The generic name Lucina, has to be dropped for other reasons.

Formation and Locality. — In the Corniferous rocks of Kentucky and Indiana, around and at the
Falls of the Ohio, where specimens of exquisite beauty and perfection, with the exterior shell as well as
internal casts are found.

Paracyclas elongata. u. SP.

Plate II., figure 8.

This shell resembles very closely P. lirata of Conrad, but it differs from it
greatly in form, so much so, that any one must distinguish the two species at
the first glance. While P. lirata has almost the shape of a regular circle,
this shell has the form of an ellipse, in which the larger axis exceeds the

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 211

smaller one considerably. In this shell the width is only about three-fourths
of the length. It is covered with strong concentric striae, which are sharply
marked, almost all parallel to each other and equidistant. The depression of
its dorsal margin in front of the beaks is very conspicuous ; the illustration
does not show this at all, or very faintly. The beaks are close to the anterior
margin ; the anterior slope is steep, while the posterior one has only little fall.
The size of this shell varies in different specimens ; it agrees generally with
that of P. lirata. Both valves are moderately convex.

It differs from P. lirata by its elongate shape and by the position of its
beaks, which is sub-anterior, while the position of the beaks in P. lirata is
almost central.

Formation and Locality. — Found in the cherty layers superimposed upon the hydraulic limestone
of the Devonian formation, in Jefferson county, Ky., and in Clark county, Ind. It may be possible that
some intermediate forms exist which connect this new species with P. lirata; but it appears to me that
both species are sufficiently different to guarantee the existence of the new one.

Paracyclas lirata. CONRAD.

Plate II., figures 4, 5, 6 and 7.

Posidonia lirata, Conrad. Geol. Surv. N. Y., Ann. Kep. — 1838.
Paracyclas lirata, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 441, pi. 72, figs. 2-19.

Shell of medium size, sub-circular or broadly elliptical ; length a little
greater than height; margins regularly rounded. Cardinal lines short, less
than half the length of the shell. Valves moderately convex below, becoming
gibbous on the middle and above.

Beaks anterior to the center; small, appressed, rising but little above the
hinge-line. Post- cardinal slope not defined.

Surface marked by fine concentric striae, and by strong, sub-angular, con-
centric ridges, which are more or less sharply defined, depending upon the
condition of the specimen and the nature of the matrix in which the fossil is
imbedded.

Ligamental grooves distinctly marked and only moderately divergent from
the cardinal margin.

In form this shell is very like the elliptica, but considerably smaller in size,
and marked by more or less distinct, angular, concentric ridges. It also re-
sembles Lucina lineata of Goldfuss, from the Devonian formation in Germany,
with which it may be found specifically identical. (Hall.)

The size of this species is very variable, as may be seen from the figures on
plate 2, which are of natural size. Prof. Meek, in the first volume of the
Palaeontology of Ohio, has figured and described a Par. ohioensis, which bears
a very close resemblance to Par. lirata, and differs only from the latter by a

212 PALEONTOLOGY OF KENTUCKY.

flange attached to the margin of the shell. It is considered by some geologists
as identical with Par. lirata.

Formation and Locality. — In the Corniferous limestone of the Devonian formation in Jefferson
county, Ky., and in Clark county, Ind., where it is found rather abundantly, and in well preserved speci-
mens, which are always entirely silicified.

Paracyclas octerlonii. ».SP.

Plate XXXI., figure 18.

The shell of this species agrees, in every particular, with that of the preced-
ing species, except in size and form. It is considerably smaller than elliptica,
measuring somewhat less in width, and considerably less in length. Its form
is peculiar, having its anterior and posterior margins almost straight and par-
allel. Orlando Hobbs, Esq., of Jeffersonville, Ind., presented me with the
first specimen of this species, and drew my attention to its peculiar shape,
which could not be the result of distortion, inasmuch as the shell did not show
the least sign of any violence. Afterwards I came in possession of a great
number of specimens, all of which have exactly the same figure ; but I never
obtained forms which, as intermediates, could have connected them with the
elliptica. These differences are so well marked, and appear to be constant,
and I, therefore, considered them sufficient to base upon them a new species.
Should hereafter such forms be found, which will connect them with the ellip-
tica, they will, even then, retain at least the character of a variety.

Most all distorted specimens of Par. elliptica, which came under my observa-
tion, I found to be compressed in the direction from base to hinge-line ; never
in the direction from the front to the rear, which is easily explained by the
fact that the Lamellibranchiata generally rest upon the base of their shell,
placing the hinge on top. Any compression will be caused by the weight of
superimposed bodies, and will result in reducing of the width and enlarging
of the length.

Formation and Locality. — This species is found associated with the preceding species in the Cor-
niferous limestone of Kentucky and Indiana, at and near the Falls of the Ohio. It is somewhat rare, at
least well preserved specimens are seldom found. I have named this species in honor of Dr. John A.
Octerlony, of Louisville, Ky., who is not only an excellent physician, but also an ardent student of Natural
Sciences, and especially of Geology and Palaeontology

FOSSILS OF THE SILURIAN AND DEVONIAN EOCKS. 213

Paracyclas ohioensis, MEEK.

Plate V., figure 20.

Lucina ohioensis, Meek. Proc. Acad. Nat. Sci. Phil., p. 6 — 1871.

Compare Posidonia lirata, Conrad. 1838, see fig. 12, pi. 2, 13th Rep. on St. Cab. of N. Y.
Lucina (Paracyclas) ohioensis, Meek. Pal. of Ohio, Vol. 1, p. 199 — 1873.

Shell of less than medium size ; compressed or only slightly convex, and
more or less nearly circular, though in some specimens greatly deviating from
that form, as is shown in the specimen illustrated on plate 5, figure 20 ; beaks
small and appressed, and very little elevated above the dorsal margin; they
are situated about in the center of the dorsal border. The anterior margin is
rather abruptly compressed above, just in front of the beaks ; hinge- margin
short and rounding into the posterior dorsal outline ; posterior dorsal slopes
of each valve marked by a strongly oblique sulcus, extending from the back
part of the beaks to the upper portion of the posterior margin, to which it
imparts a slightly sinuous outline at its termination.

Surface ornamented with small, more or less regular, concentric undmations,
which are most strongly defined on the umbones. The average size of shells
belonging to this species is represented in the specimen illustrated on plate 5,
figure 20.

This species is closely allied to Par. lirata, with which it is considered iden-
tical by some palaeontologists ; but its peculiar posterior dorsal sulcus is such
a prominent feature, that it may be regarded of sufficient importance and
value to base upon it a separate species.

Formation and Locality.— It occurs, together with its associates and congeners, the Par. elliptica}
lirata, elongata and octerlonii,5n the upper strata of the Devonian formation, in Jefferson county, Ky., and
in Clark county, lud. It is, however, very rare in our rocks, where, so far, only a few specimens have
been found.

Genus Goniophora. Phmips.

Goniophora, Phillips — 1848.

Etymology : gonia, an angle; phoros, bearing.

Shell equivalve, very inequilateral, rhomboidal or trapezoidal in outline;
obliquely truncate behind and rounded in front. Cardinal line usually straight
and not oblique. Beaks small, closely incurved, situated within or about the
anterior third of the shell. Umbo prominent. Umbonal slope continued as a
strong angular ridge to the post-inferior margin. The valves are crossed
obliquely, sometimes vertically, by a broad, undefined sinus, extending from
anterior of the beaks to the basal margin, which is usually slightly constricted
at this point.

214 PALAEONTOLOGY OF KENTUCKY.

Surface marked by more or less regular concentric striae, which may be either
simple throughout or fasciculate on the anterior portion of the shell. Some
species are marked by strong, radiating striae upon that portion of the valves
between the umbonal ridge and the sinus.

Hinge furnished with a strong oblique fold or tooth in the left valve, situ-
ated just beneath the beak, and a corresponding depression in the right valve.
No lateral teeth have been observed. Ligament external, strong; its attach-
ment to the shell is marked by one or more defined grooves. Muscular im-
pressions two ; the anterior one deep and strongly marked, situated a little
anterior to the beak and just within the anterior margin. Pallial line simple,
continuing nearly parallel to the basal margin until it crosses the umbonal
ridge, and recurving to the posterior muscular impression, which is large arid
shallow, and situated on the posterior cardinal slope, sometimes near the mid-
dle of length of shell.

This genus was proposed by Phillips in 1848, as a generic designation for
the original Cypricardia cymbiformis of Sowerby, but without generic defini-
tion or illustration of internal characters, and, so far as known, the genus
has never been heretofore described.

Goniophora truncata. HALL.

Plate IV., figures 21, 22 and 23.

Goniophora truncata, Hall. Pal. N. Y., Vol. 5, pt. 1, pis.— 1883.
Goniophora truncata, Hall. Pal. IS. Y., Vol. 5, pt. 1, p. 298—1885.

Shell of medium size, in a side and front view sub-triangular, in a dorsal
view sub- elliptical. Length about twice as great as height ; anterior end of
the basal margin rounded, middle portion slightly sinuate, and the rear por-
tion nearly straight or slightly curved to the post-basal extremity ; posterior
margin obliquely sub-truncate, slightly curving. Cardinal line short and
straight. Anterior end short and rounded. There is a broad, shallow de-
pression extending from the beaks obliquely across the valves to the central
point of the basal margin ; this last feature is only faintly expressed in some
specimens, and in others entirely obsolete. Valves convex below the umbonal
ridge, gibbous in umbonal region. The area above the umbonal ridge, which
I called [in Cypricardinia cataracta the dorsal incline, is usually flattened or
very slightly convex ; in some shells it is even concave. The beaks are entirely
anterior, acute and incurved ; in some shells they are closely appressed, while
in others they are separated by a small interspace.

The umbonal ridge is strongly defined, forming a very sharp edge, separating
the lateral areas of the valves from their dorsal incline. Cardinal line is short
and straight, the umbones are more or less prominent and somewhat angular.
Test is of moderate thickness, the entire shell marked by stronger and finer

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 215

radiating and concentric striae, which differ in their character, according to
the places they occupy. On the baso-lateral area of each valve there are sub-
angular, abruptly elevated, concentric striae in their course from the anterior
margin to the umbonal ridge, where they terminate parallel to the anterior
and basal margins. These elevated striae have flat interspaces of different
width, sometimes three or four times as large as the striae. Some of these
interspaces are smooth, while others are occupied by one to three finer striae.
Between the umbonal ridge and the sinus, mentioned above as a shallow
depression crossing obliquely the valves, these interspacial finer striae become
more prominent, and some more are added by intercalation, thus causing them
to appear somewhat crowded. In this region, limited by the umbonal ridge
and the lateral sinus, the concentric striae are crossed by fine, closely arranged
radii, giving that portion of the surface a cancellated, somewhat rugose appear-
ance. This cancellated belt commences at the apical end of the umbonal ridge,
increases regularly, but rapidly in width, until it occupies, in the basal margin,
the whole posterior half of the shell.

The dorsal incline is covered by subequal, rounded, and closely set radii,
which start from the posterior portion of the cardinal line, and extend along
the cardino-posterior margins to the umbonal ridge ; they increase in number
by bifurcation and interpolation.

I do not know any other Goniophora, and can not, therefore, compare this
species with any of its congeners. Prof. Hall compares it with G. perangulata
of the Schoharie grit, with which he thinks it may be identical. In comparing
my specimens with his figures of that species, it appears to me that there is a
vast difference between both species.

Formation and Locality. — This shell occurs in the Corniferous limestone of the Deronian forma-
tion in Kentucky and Indiana, at and around the Falls of the Ohio. It is a very rare shell ; the two
specimens in my own collection are, so far, the only individuals found in our rocks.

Genus Modiomorpha. Han.

Modiomorpha, Hall. Prel. Notice of Lam. Shells — 1870.

Etymology : Contracted from modiola, a genus of shells ; and morphe, form or shape like Modiola.

Shell inequivalve, very inequilateral, compressed, sub-ovate in outline,
largest posteriorly; beaks small, compressed, usually situated within the
anterior third of the length. Surface of shell marked by rugose or undulating
concentric striae, which usually coalesce or become fasciculate toward the
anterior end. The valves are crossed obliquely by a more or less distinctly
defined sinus passing from the beak to the base, and constricting the basal
margin ; the anterior end is rounded, forming a projecting lobe of greater or
less extent beyond the beak. Hinge characterized by a single, strong, wedge-

216 PALEONTOLOGY OF KENTUCKY.

form tooth in the left valve, and a corresponding cavity in the right ; no lateral
teeth exist. Anterior muscular impression sub-circular, situated within the
anterior extension of the shell ; posterior impression large and superficial, sit-
uated near the cardinal border ; pallial line entire. Ligament external,
attached to the thickened margin of the shell.

This genus is allied to Modiola, Modiolopsis and Cypricardites, but differs
from Modiola in the toothed hinge ; from Modiolopsis in not having lateral
teeth, and from Cypricardites in general aspect. Modiomorpha concentrica
may be considered the type of this genus.

Modiomorpha affinis, HALL.

Modiomorpha alia, in part (Conrad), Hall. Pal. N. Y., Vol. 5, part 1, Plates and Explanations pi. 37, figs

13 and 14—1883.
Modiomorpha affinis, Hall. Pal. N. Y., part 1, page 284—1885.

Shell large, robust, obliquely ovate, arcuate ; length about one-third greater
than the height; basal margin straight or slightly arcuate, curving rather
abruptly both at the anterior and posterior extremities; posterior margin
abruptly curving below and more gently forward to cardinal margin ; cardinal
margin arcuate from the beaks to the post-cardinal extremity. Anterior end
short, scarcely denned ; narrow, declining from the hinge-line and regularly
rounded below.

Valves convex, very gibbous in the middle and umbonal region ; depth more
than half the height of shell. The umbonal elevation extends from the beaks,
curving above the middle to near the post-basal margin, forming an undefined
arcuate ridge.

Hinge-line oblique, extending more than one -third the length of the valves.
Beaks small, sub-anterior, and closely incurved.

Test comparatively thick, marked by fine concentric striae, which are fascicu-
late and pass into strong abrupt ridges upon the umbonal and anterior portions
of the shell. Interior unknown.

An individual of average size, among the specimens of this species in my
collection, measures as follows : length, twenty -one lines ; height, sixteen lines,
and thickness, eleven lines.

This form resembles Mod. alta, but is more elongate, distinctly arcuate ;
the anterior end is narrower below the beaks ; the posterior end is more pro-
duced, and curving more abruptly forward in the upper part, with the post
cardinal angle rounded. The anterior end is less produced than in typical
forms of Mod. mytiloides.

Formation and. Locality. — Found in the cherty layers superimposing the hydraulic limestone of
the Devonian formation, in Jefferson county, Ky., and in Clark county, Ind. Almost all my specimens 01
this and other species of Modiomorpha were found in the cement quarries at "Watson Station, in Clark
county, Ind., about six miles distant from the Falls of the Ohio,

FOSSILS OF THE SILURIAN AND DEVONIAN BOOKS. 217

Modiomorpha alta. CONRAD.

Plate XXVI., figure 10.

Cypricardites alta, Conrad. Geol. Surv. N. Y., Ann. Rep., p. 52 — 1841.
Modi oinorpha alia (Conrad), Hall. Prelim. Notice Lamellib. 2, p. 75 — 1870.
Modiomorplw alia (Conrad), Hall. Pal. N. Y., Vol. 5, pt. 1, pi. and exp. — 1883.
Modwmarpha alta, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 278—1885.

Shell above medium size, broad, rhomboid-ovate; length about one-third
greater than height ; the basal margin, for two-thirds of its length from the
anterior curve, is nearly straight, varying from slightly concave to nearly
straight, abruptly curving at the post-basal extremity, and continuing to the
post-cardinal margin in an oblique, gently curved line. In some examples,
the posterior margin is regularly curved, cardinal margin sometimes forming
a nearly straight line, usually gently arcuate. Anterior end produced beyond
the beak from one-sixth to one-fourth the length of the shell ; obliquely trun-
cated, obtuse, rounded below; its greatest extension is below middle of the
shell.

Valves convex, gibbous on the umbonal and medial portion of the shell ; the
umbonal ridge is gibbous and arched upward ; the point of greatest convexity
is about the middle of the shell or a little posterior. The depth of both valves
is equal to two-thirds of the height of the shell.

Hinge-line straight, oblique, extending for less than half the length of the
shell. Beaks rounded, somewhat appressed, directed forward. Umbonal
region not strongly defined, depressed anteriorily, becoming gibbous in the
middle of the shell, gradually merging into the general contour in the pos-
terior portion.

Test of moderate thickness, marked by irregular concentric striae, which
become fasciculate and produce strong concentric ridges at irregular intervals.
The surface is marked by fine vascular lines, similar to those on Mod. mytil-
oides. The anterior muscular impression is situated close to the anterior
margin of rthe shell, with a small retractor scar above it. Other characters
of the interior unknown.

The specimen illustrated on plate 26, figure 10, is rather shorter than the
average. An individual of average size has the following dimensions : length,
twenty-three lines ; width, fifteen lines, and thickness, ten lines.

This species has a greater proportional height than Mod. mytiloides, a
broader and often sub-truncate posterior end, while the anterior end is usually
broader and less extended ; the umbonal ridge is arcuate ; in other features it
is very similar. In some of its conditions this species is not easily distin-
guished from Mod. mytiloides.

Formation and Locality. — Pound associated with Mod. ooncentrica, mytiloides and affinis, in the
cherty strata topping the hydraulic limestone, in Jefferson county, Ky., and Clark county, Ind.
OKOL. SUR. — 28

218 PALAEONTOLOGY OF KENTUCKY.

Modiomorpha charlestowuensis. v M-.

Plato V., figures 7, 8 and 9.

The shell illustrated on plate 5, figures 7, 8 and 9, has evidently its valves
dislocated. The right valve is more than one-eighth of an inch removed back-
ward.

Shell of about medium size, elongate, sub-elliptical, very ventricose or gib-
bous; greatest height at about one- third of length from the anterior extremity ;
valves strongly convex, the greatest convexity being a little anterior to the
middle of shell. Hinge-line oblique, almost straight, and of about one-half
the length of shell. Beaks anterior or sub-anterior, acute and closely ap-
pressed. Umbonal region strongly convex, angular, and inflected on its dorsal
slope near the beaks, regularly curved on its ventral and posterior slopes, and
also in the posterior half of its dorsal slope ; prominently ridged. The course
of the umbonla ridge forms an acute angle with the cardinal line, and runs
somewhat diagonally to the posterior extremity, where the post-ventral and
post-dorsal margins meet in a very abrupt curve.

Ventral or basal line almost straight, only slightly incurved in its central
portion ; at its posterior end it curves regularly and gently upwards into the
abrupt curve at the posterior extremity. The posterior part of the dorsal line
forms a gentle regular curve from posterior end to hinge-line

Anterior end short, its margin straight and sloping almost rectangular with
the cardinal line down to the basal margin, which it meets in a short curve.

Surface covered by fine concentric lines of growth, which, at irregular inter-
vals, have been raised into imbricating lamellae, leaving strong varices on the
cast.

A portion of the shell remaining shows the concentric lines as closely set as
on Mod. concentrica, and if the form of my shell did not differ so greatly from
that of Mod. concentrica, I would have placed it with that species. Its elon-
gate form, its great gibbosity, its linguiform posterior end, and the marked
concentric zones on its surface, distinguish it from its other congener, with
which it is associated in our rocks.

Formation and Locality. — The chert beds over the hydraulic limestone of the Devonian formation
in. Jefferson county, Ky., and in Clark county, Ind.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 219

Modiomorpha concentrica. CONRAD.

Plato II., figures 9, 10, 11, 12 and 14.

Plerinea concentrica, Conrad. Geol. Surv. N. Y., Ann. Rep., p. 116—1838.
Cypricarditcs concentrica, Conrad. Geol. Surv. .N. Y., Ann. Rep , p. 52 — 1841.
Cypricardites oblonga, Ibidem.

Modiola concentrica, Hall. Geol. Surv. N. Y., Rep. 4th Dist.— 1843.
Modiomorpha concentrica, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 275—1885.

Shell of medium size, ovate, extremely variable in its proportions ; length
less than twice the height ; basal margin often nearly straight, usually a little
concave on the anterior one-third ; posterior margin rounded abruptly below,
but gently curving above. Cardinal margin oblique in the prevailing forms,
moderately arcuate, often nearly straight ; sub-alate in many specimens. An-
terior end produced beyond the beaks, many specimens only slightly, abruptly
rounded, sometimes nasuate, limited by a broad depression extending from the
beak to about the anterior third of the basal margin. In our Kentucky shells
the shape differs as regards the anterior end, which is not at all, or at least
only slightly produced beyond the bend; the anterior margin is almost straight
or little curved, and turns at the beaks abruptly down to the basal margin.

Valves moderately convex, but somewhat gibbous along the umbonal slope ;
the point of greatest convexity is about one-third of the length from the an-
terior margin. Hinge-line extends generally to the middle of shell, sometimes
even beyond the same.

Beaks sub-anterior (in our western shells anterior), small, sharply angular,
appressed, directed forward. Umbonal region a more or less prominent sub-
angular elevation, extending obliquely from beak towards the post-basal
margin, but usually dying out about the middle in the length of the shell.

Test comparatively thick, and ornamented by concentric, rounded or sub-
angular striae, which become lamellose and coalescing on the anterior end of
the valves, where they are less prominent.

Anterior muscular impression strong, striated, situated just within the
anterior margin, with a small retractor scar above it. Posterior impression
large and shallow. Pallial line moderately impressed. Hinge furnished with
a strong cardinal tooth just posterior to the beak in the left valve, and a
corresponding depression in the right valve. No proper lateral teeth have
been observed, but the cardinal margin is thickened and grooved from the
beak backward about half the length of the cardinal line. It is impossible to
give in figures the dimensions of the different individuals, nor the different
sizes of the specimens. The proportion of length, width and thickness is as
variable as the sizes of the different shells. The illustrations on jjlate 2 give
the sizes of average specimens.

Formation and Locality. — Found associated with Ptyohodesma knappiana in the oherty layers
of the Devonian limestone, in Jefferson county, Ky., and in Clark county, Ind., at and around the Palls of
the Ohio. It occurs rather abundantly in fractional shells, but fair specimens are not often met with.
The shell illustrated by figure 14, plate 2, has two beautiful orania attached to its surface.

220 PALEONTOLOGY OP KENTUCKY.

Modiomorpha mytiloides. CONRAD.

CypricarditiS mytiloides, Conrad. Geol. Surv. M. Y., Ann. Rep. — 1841.

Modiomorpha complanata, Hall. In err. Pal. N. Y., Vol. 5, pi. 1, plates and explanations, pi. 38, figures

1-16—1883.

Modiomorpha planulala, Hall. Prelim. Notice Lamellib. 2, p. 74 — 1870.
Modiomorpha mytiloides, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 277—1885.

Shell larger than medium size, rhomboid- ovate, oblique ; length less than
twice the height ; basal margin nearly straight, or very slightly concave ante-
rior to the middle, curving to anterior and posterior extremities; posterior
margin abruptly curving below, and more gently recurving toward cardinal
line ; cardinal margin arcuate. Anterior end narrow, extended, abruptly
curved on the margin ; somewhat defined by the sinus, which extends from
anterior of the beak to the middle of the shell.

Valves moderately convex, in old shells gibbous in the umbonal region.
Hinge-line oblique, extending to about the middle of length of shell.

Beaks appressed, situated a little more than one-fourth the length of shell
from anterior end. Umbonal region not defined; convex in young specimens,
becoming more gibbous in older ones.

Test of moderate thickness, concentrically striated with irregular lines of
growth, which are sometimes elevated into concentric ridges. The post-cardi-
nal slope in well-preserved specimens shows fine vascular markings. The an-
terior muscular impression is well marked, and situated just within anterior
margin below beak. Other interior characters are not known.

An average sized individual of this species has the following dimensions :
length, twenty-six lines ; width, seventeen lines, and thickness, ten lines.

This species resembles somewhat in form Mod. concentrica, but its anterior
end is more produced, and it does not show the concentric striae of that
species. It also resembles some forms of Mod. alta, but is more elongate, and
possesses a more regularly rounded posterior extremity, and a narrower an-
terior end.

Formation and Locality. — Occurs in the chert of the Devonian formation in Jefferson county, Ky.,
and in Clark county, Ind., in company with its congeners, Mod. concentrica, alta and affinis. Watson's
Station, in Clark county, Ind., on the Ohio and Mississippi Railroad, furnishes fair specimens in a silicified
condition.

Genus Nucula.

Lamarck.

Nucula, Lamarck. Hist. Nat. Des. An. Sans Vert. — 1815.
Etymology: nucula, a little nut.

Shell small, equivalve, inequilateral, trigonal or transversely elliptical or
sub-circular. Anterior or posterior extremity sometimes produced, usually

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 221

rounded. Beaks anterior or posterior to the middle of the length, often sub-
central. Cardinal line arcuate ; escutcheon marked. Surface marked by con-
centric striae, which, in some species, are regular and rugose.

Hinge furnished with a triangular, spoon- shaped cartilage-pit beneath the
beaks, with a series of small transverse teeth on each side. There are two
principal muscular impressions in each valve, with usually a smaller retractor
scar adjacent, and also the cavity of the beaks often shows several pits for the
attachment of umbonal muscles. Pallial line simple.

Examples : Nucula varicosa and N. randalli. (Copied from Hall's Lamelli-
branchiata.)

NUCUla. Lamarck.
Etymology : nucula, a little nut.

Nucula herzeri. N.SP.

Shell small, elongate, sub- trigonal ; very gibbous.; length one and one-half
the height ; both terminal extremities very narrow, almost pointed ; beaks
prominent and closely incurved ; situated about one-fourth of the whole length
from the anterior end ; basal margin in its main portion only slightly convex,
even at its anterior end, where it joins the anterior margin, which is most
prominent close to the basal line ; at the posterior end the basal margin turns
in a light regular curve upwards to the very narrow, often pointed, posterior
margin. The cardinal margin slopes in a straight line down to the posterior
extremity, and with an inflected curve very abruptly to the anterior extremity ;
umbones very ventricose, making the thickness of the shell equal to its
height.

This species is associated with Nuc. niotica and neda, which it resembles in
some points, but is easily distinguished from them by its elongate form, its
pointed terminal extremities, and the equality between its depth and height.
An average-sized specimen of this species has the following dimensions: length,
one-half inch; height and depth, one- third of an inch.

Formation and Locality. — Occurs in the cherty layers overlying the hydraulic cement rock of
the Devonian formation around the Falls of the Ohio in Kentucky and Indiana, I dedicate this pretty
little shell to Rev. H. Herzer, formerly of Louisville, Ky., who devoted his spare time to the study of
Natural Sciences, and especially to that of Palaeontology. It was 'he who rekindled in me the love for
Geology, which was almost extinguished by many years of hard work, but which since has afforded to mo
so many hours and days of genuine enjoyment.

222 PALEONTOLOGY OF KENTUCKY.

NuCUla neda, HAM. AND WIIITKIKLD.

Plate V., figures 5 and 6.

Nucula neda, H. and W. 24th Eeg. Kep., p. 191—1872.
Nucula neda, H. and W. 27th Reg. Rep., pi. 11— 1875.

Shell cuneiform, sub-trigonal, with the umbones ventricose ; the beak a
little more than one-third from the anterior end, prominent and incurved.
Cardinal margin sloping to the anterior and posterior extremities ; basal mar-
gin straight.

The «ast shows strong anterior and posterior muscular impressions, with
three or four umbonal muscular scars ; a narrow pedal scar just within the
cardinal line, anterior to the posterior muscular area, as usual in the genus
Nucula.

The surface has been marked by fine concentric lines of growth. It is asso-
ciated with Nucula niotica, which it resembles in many features, but it differs
from it in several points, which are given in the description of that species.

Formation and Locality. — Occurs in the chert beds superimposed upon the hydraulic limestone of
the Devonian formation, around the Falls of the Ohio, in Kentucky and Indiana.

NllCllla niotica. HALL AND WHITFIELD.

Plate V., figures 2, 3 and 4.

Nucula niotica, H. and W. 24th Regent's Rep., p. 190 — 1872.
Nucula niotica, H. and W. 27th Regent's Rep., pi. 11—1875.

Shell small, obtusely cuneiform; the beaks prominent, incurved, with the
umbo inflated ; height from beak to base equal to three fourths the length of
the shell. Surface marked by fine, even, concentric striae, with sometimes
strong varices of growth. The internal casts show the evidence of strong,
anterior and posterior muscular im pressions, and three distinct umbonal pedal
muscles, seven or more posterior and five anterior teeth in a specimen of me-
dium size. Hall's description.

We find three distinct Nucula in our rocks; two of the species have a cunei-
form sub- trigonal form, as shown in Prof. Hall's figures of Nucula neda and
niotica; they must, therefore, be the two species in question ; but which is neda
and which is niotica? Prof. Hall's descriptions and figures of both species may
answer to either one. There is only one point in the descriptions which may
decide the question ; this is the character of the respective umbones. Accord
ing to Hall, the umbo of N. niotica is inflated, and the umbo of the neda is
ventricose. Basing my identification of the two species upon this single point
of difference, I will try to point out a few more distinguishing features. Nu-
cula niotica differs from Nucula neda in the following characters :

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 223

1. In N. niotica the umbo is inflated, in .Nucula neda it is very ventricose.

2. In N. niotica the depth is only one-half of the depth of neda, measured
in specimens of the same size, at the point of their greatest convexity.

3. In !N. niotica both slopes of the beaks are concave, while those in N. neda
are almost straight.

4. In N. niotica the basal margin is broadly curved, while that of N. neda is
straight or even inflected.

Formation and Locality. — Irrthe chert beds over the hydraulic limestone of the Devonian forma-
mation, in Jefferson county, Ky., and in Clark county, Ind. Pound in silicified, fairly preserved speci-
mens; not very rare.

Yoldia? ValvulUB. HALL AND WHITFIBLD.

.Plate IV., figures 4 and 5.

Yoldia ? valvulus, H. and W. 24th Regent's Rep., p. 190—1872.
Yoldia ? valvulus, H. and W. 27th Regent's Rep., pi. 11—1875.

Shell elongate, narrow, sub-elliptical, more than twice as long as high, the
depth a little more than half the height ; anterior end nearly one-fourth wider
than the posterior. Beaks situated at three-fifths the length from the anterior
end ; an obsolete post-umbonal ridge extending from near the beak to the
post-basal margin ; posterior extremity not recurved.

Surface marked by somewhat coarse, wavy, concentric lines to the post-
umbonal ridge, above which they are even and much finer.

i

Formation and Locality. — Occurs above the hydraulic limestone in the cherty layers of the De-
vonian formation, in Jefferson county, Ky., and in Clark county, Ind., where it is found rather abundantly
in silicified specimens. It is represented by fair individuals in several collections in the Falls Cities.

Genus Aviculopecten. McCoy.

Etymology: resembling the shells of the genus Avicula.
Aviculopecten CraSSlcOStatllS. HALL AND WHITF^ELD.

•

Aviciilopectfn crassicasta/Ms,H. and W. 24th and 27th Reg. Reps., p. 188, and pi. 11—1872 and 1875.

Shell below medium size, its body broadly ovate or sub-elliptical. The left
valve is only known to me, and shown in the specimen before me ; it is de-
pressed convex ; body of the shell oblique ; hinge-line straight, equal to three-
fourths the length of the shell ; anterior wing very small, separated from the
body of the shell by an abrupt deep sinus; posterior wing narrow, obtusely
pointed, and extending nearly as far as the posterior extremity.

Surface marked by strong, coarse, angular ribs, of which there are about

224 PALAEONTOLOGY OF KENTUCKY.

»

thirteen or fourteen on the body of the shell, with intermediate smaller ones ;
about five obscure rays on the posterior wing ; the radiating costae crossed by
coarse, distant, lamellose, concentric ridges.

Formation and Locality. — Found in the hydraulic limestone of the Devonian formation at the
S*aih of the Ohio, in Kentucky and Indiana, where it is a rather rare shell.

Aviculopecten fasciculatus. HALL.

Plate III., figure 4.
Aviculopecten fasciculatus, Hall. Pal. N. Y., Vol. 5, pt. 1, page 11 — 1883.

Shell small, obliquely and transversely ovate ; height about equal to length,
the former measuring more than seven-eighths of the latter. Pallial margins
regularly rounded, becoming more convex towards the middle of the posterio
lateral margin, and extending in a straight or slightly concave line to the
beaks. The left valve is only known to me ; it is slightly convex in its basal
half, but more so in the umbonal region ; the umbo is prominent, and the beak
pointed and incurved. The hinge-line is straight and shorter than the width
or length of the shell ; this is situated anterior to the middle of the cardinal
line. The anterior ear is considerably smaller than the posterior wing ; both
are triangular in shape, and both are defined by a sulcus, of which the posterior
one is more expressed and deeper. The posterior wing is very attenuate at the
extremity. Figure 4, plate 3, does not show the correct shape of the rear wing;
it should be more extended in the hinge-line, and should reach downward
only half as far as it does in that figure. The terminal margins of both wings
should be concave, and should join the lateral margins of the shell in a regular
curve, and not, as represented in the figure, by straight lines.

The test of this shell is ornamented with numerous filiform, radiating striae,
which are often fasciculate, and by fine concentric lines of growth. In young
shells the radii are regular, with a slight fasciculate arrangement. The concen-
tric lines are sharper and more crowded on the wings, while the radii are very
much subdued, almost obscure. The interior of this shell is not known,
neither have I ever seen its right valve.

The specimen here figured and described measures eight lines in height,
nine lines in length, and its hinge-line is five lines long. This species has some
resemblance with A. formio, princeps and pecteniformis, but differs from them
partly by its form, and partly by its surface-markings ; from A. princeps
mainly by the presence of radii on its wings.

Formation and Locality, — Found in the Corniferous limestone of the Devonian formation in
Kentucky and Indiana, at and around the Falls of the Ohio.

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 225

Aviculopecten pecteniformis. CONRAD.

Plate III., figure 1.

Avicula pecteniformis, Conrad. Jour. Acad. Nat. Sci. Phil. — 1842.
Aviculopecten pecteniformis, Hall. Pal. of N. Y., Vol, 5, pt. 1, p. 4 — 1883.

Shell sub-ovate, oblique to the hinge-line ; length about equal to height ;
anterior and basal margins regularly rounded, while the posterior margin of
the body forms an almost straight line to beak. Left valve almost flat, only
moderately convex in the umbonal region. The hinge-line is straight, and of
about two-thirds the length of shell, or even somewhat more. Umbo moder
ately elevated, abruptly sloping to the wings, thus forming a demarcation-line
between the ears and the body of valve. These umbonal lines form an angle of
a little more than ninety degrees. The wings have a triangular form and are
of medium size, the anterior one having but little more than half the area of
posterior wing. The beak is of moderate size and pointed ; it is located ante-
rior to the middle of the cardinal line. The terminal margins of the wings
are more or less concave. The interior of this shell and its right valve are not
known.

Test is thin and ornamented by about thirty-five sharp and strong radiating
striae, with intermediate finer ones, which are crossed by fine, imbricating,
concentric lines of growth, some of which are more prominent, and divide the
surface in different concentric zones.

On the wings the radiating striae are obsolete, and even the lines of growth
are there scarcely visible. This species is variable in its dimensions in differ-
ent specimens. The one before me measures twenty-five lines in height, by
two inches in length, and with a hinge-line of one inch and one-half.

This species has great resemblance to A. princeps, from which it differs,
however, by its smaller ears, and by its coarser or stronger principal radii,
while the intermediate finer striae are so fine as being scarcely visible to the
naked eye, which makes the interspaces between the principal striae appear to
have three times the width of these radii.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation at and
around the Falls of the Ohio, in Kentucky and Indiana. It is a rather rare species, especially in fair or
well preserved specimens. •

Aviculopecten princeps. CONBAD.

Monotis jtrinceps, Conrad. Ann. Kep. N. Y. Geol. Surv. — 1838.
Avicula parilis, Conrad. Proc. Acad. Nat. Sci. Phil., Vol. 8—1842.
Aviculopecten princeps, Hall. Pal. N. Y., Vol. 5, pt. 1 — 1883.
Aviculopecten sanduskyensis, Hall. Pal. N. Y., Vol. 5, pt. 1 — 1883.

Shell large, obliquely broad-ovate ; axis inclined more than sixty degrees to
the hinge-line ; length and height nearly equal, varying within moderate

GEOL. SUK. — 29

226 PALAEONTOLOGY OF KENTUCKY.

limits. Anterior margin convex, the convexity increasing to the middle of
the postero-lateral side, thence truncated and extending in a straight line to
the beak, making an angle of from thirty to forty degrees with the hinge-
line.

Valves depressed ; left valve regularly convex ; right valve nearly flat or
only slightly convex. The hinge- line is straight, having a length of from
two-thirds to more than three-fourths the length of the shell, and extending
anteriorly as far as the anterior margin. The beaks are obtuse, rounded and
anterior to the middle of the hinge-line. Umbo of left valve is little convex,
somewhat inflated, and the lines of demarcation between it and the anterior
and posterior wings form an angle of about one hundred and thirty degrees.
The wings comparatively only of medium extent ; the anterior considerably
smaller than the other ; both are triangular in shape. The anterior ear is sepa-
rated from the body by a distinct sulcus, while the posterior wing is defined by
the abrupt slope of the posterior side of the umbo. This slope is formed by
an almost rectangular deflection of the posterior margin, and has a height of
about one line. The terminal margins of the beaks are more or less concave,
becoming convex at the hinge-line. Byssal sinus broad, rounded, well defined,
and indicated on the ear by a sulcus extending to the extremity of the beak.

Test is thin, marked by numerous regular alternating rays or radii, which
increase in number by interstitial additions, and become broader and stronger
towards the margins. These radii are crossed by very fine, sharp lines of
growth. On the wings the radiating striae are obsolete, while the lines of
growth are there sharper and stronger than on the body of the shell.

The dimensions of the shells in this species are very variable ; there are very
large and also very small specimens. The one before me, which is one of the
largest ever found, measures thirty lines in height, thirty- two lines in length,
and has a hinge-line twenty-seven lines long ; here the length exceeds the
height, and the hinge-line is shorter than height or length ; but we find speci-
mens belonging to this species where all three dimensions are nearly equal.

This species resembles A. pecteniforniis, but differs from it by its larger
wings and by its more numerous and less prominent radii. This is one of the
largest shells of the genus Aviculopecten, and is easily identified by its form
and surface-markings. All the forms heretofore placed In the two species of
A. sanduskyensis and A. parilis, belong to the present one. The apparent spe-
cific differences noted in the description of these three forms are neither con-
stant nor well defined, and not even sufficient to base upon them a separation
into different varieties.

Formation and Locality. — This species occurs in the Corniferous limestone at and around the Fall*
of the Ohio, in Kentucky and Indiana, where fair specimens are not very rare, though not abundant
either,

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 227

Genus Glyptodesma. Han.

Glyptodesma, Hall. N. T. Rep., Vol. 6, pt. 1.
Etymology: glyptos, curved; desm-a, a ligament.

Shell aviculoid, erect or moderately oblique ; inequivalve. Ligament exter-
nal. Ligamental area striated, continuous. Hinge with two strong, lateral
teeth, and numerous irregular transverse plications along the cardinal margin.
In form the shells of this genus resemble Actinodesma, but they have not the
permanent diverging teeth of that genus. Surface marked by concentric
striae.

Glyptodesma cancellata. N. SP.

Plate V., figure 1.

Shell large, regularly oviform in its body, almost erect or slightly oblique ;
height exceeding length ; anterior and posterior margins broadly rounded ;
front or base strongly curved ; posterior wing large ; its posterior margin con-
cave, and its extremity produced to a salient point ; anterior wing defective
in the specimen before me, but it appears to be short, and of the shape as
indicated in figure 1, plate 5. The hinge-line is about equal in size to width
of the shell. Only the left valve is known ; it is very convex and gibbous in
the umbonal region, from where it slopes in a gentle curve to the margins in
the basal half of the valve. The lateral slopes of the umbonal region are
abrupt, the anterior somewhat more than the posterior. There is no sharp
dividing line between the body and wings. The posterior wing is very convex,
sloping rapidly or even abruptly to the cardinal line, which is entirely straight.
The interior of this shell and its right wing are unknown. The umbo is promi-
nent, and the beak elevated and incurved over the hinge- line ; it is located
anterior to the middle of the shell, and has an anterior direction. The surface
is marked by strong, simple, rounded, radiating plications, with wide, flat
interspaces, which are about three times as wide as the ribs. There is scarcely
an intercalated plication observed on the whole valve ; no bifurcation takes
place.

The specimen here described and figured is well preserved, with the ex-
ception of the anterior wing, which is either broken or covered with rock; this
shell measures thirty-one lines in height, by twenty-nine lines in length. The
surface is divided by several strong lines of growth into concentric zones.

Formation and Locality. — Found in the Corniferous limestone of the Devonian formation at and
around the Falls of the Ohio, in Kentucky and Indiana. The specimen illustrated on plate 5 is, so far, the
only one known.

228 PALEONTOLOGY OF KENTUCKY.

Glyptodesma occidentale. HALL.

Plate III., figure 5.
Glyptodesma occidentale, Hall. Pal. N. Y., Vol. 5, part 1, page 157—1884.

Shell large, broadly ovate ; body nearly erect ; height somewhat greater than
the length. The specimen before me measures thirty-eight lines in height by
thirty-four lines in length. All the margins are regularly curved, with about
the same radius.

Of the two valves of the shell, only the left one is known ; it is somewhat
gibbous at the umbo, from where it slopes in a gentle curve down to the base
and to the basal half of the anterior and posterior margins ; in the upper half
of the valve the lateral slopes of the umbonal region are abrupt, more so on
the anterior than on the posterior side. The hinge-line is straight and con-
siderably shorter than the width of the shell ; in our specimen it measures
about two- thirds of the greatest width of shell. Prof. Hall's figure, on plate
86, of volume 5, part 1, shows an enormously extended wing, and consequently
a very large hinge-line, but it appears to me, that in restoring the wing, which
in Prof. Hall's specimen was missing to the extent of an inch and one-quarte
on the posterior margin, a considerable mistake was made in regard to its
length, although the concentric lines, near the edge of the broken wing, indi-
cated a very mucronate one. My specimen is almost perfect and shows a wing
as illustrated in figure 5, plate 3. The beak is anterior to the middle of the
shell, with a strong inclination to the anterior end ; it is prominent and acute.
The anterior wing is short, defined by a deep sulcus, and marked byssal in-
flection or sinus just anterior to the beak. Posterior wing is large, depressed,
convex, moderately extended, joining the body of the shell at the middle, and
defined partly by the recurving of the striae, but more decidedly by a small
but plainly visible depression, which extends in a straight line from the cardi-
nal line near the beak along body of the valve to the posterior margin at the
middle of the shell. The posterior margin of the wing is slightly concave,
and its extremity somewhat produced, but not to such an extent as shown in
Prof. Hall's figure.

Test thick, marked by numerous fine striae or lines of growth, which at inter-
vals are crowded into fascicles, producing an undulating surface. These striae
are more closely arranged, and become lamellose on the anterior part of shell.
On the posterior wing the striae are regular, and at distant intervals a single
stria becomes sharply elevated. The interior of this shell and its right valve
are unknown.

This species resembles G-. erectum, but appears to be a more robust form ;
the shell is more orbicular, the umbonal region more gibbous, the surface more
rugose from the undulations of the fascicles of striae, and the limitation be-

FOSSILS OF THE SILURIAN AND DEVONIAN ROCKS. 229

tween the body and the posterior wing is less strongly defined. These are the
differences marked out by Prof. Hall. It appears to me that in all these points
shells may differ and still belong to the same species, and especially in this
case, where the most important distinction, the last mentioned one, disappears,
inasmuch as Prof. Hall did not notice in his specimen the dividing sulcus be-
tween body and posterior wing, which my shell so plainly shows.

Formation and Locality. — Found in the Corniferous limestone at and around the Falls of the Ohio,
in Kentucky and Indiana.

Genus Actinopteria.

This genus is established by Prof. Hall in his N. Y. Rep., Vol. 5, part 1,
Lamellibranchiata. His description is :

Characterized from Pterinea in the absence of a broad striated ligamental
area and strong cardinal teeth. Eight valve sub-convex. Surface with tine
rays.

Actinopteria boydi. CONRAD.

Plate III., figure 2.

Avicula boydi , Conrad. Jour. Acad. Nat. Sci. Phil. — 1842.
Avicula quadrula, Conrad. Jour. Acad. Nat. Sci. Phil. — 1842.
Actinopteria boydi, Hall. Pal. N. Y., Vol. 5, pt. 1, p. 113—1883.

Shell of medium size, rhomboidal ; body ovate, varying in the proportion
of its dimensions. Its longitudinal axis forms with the hinge-line an angle
of from forty-five to sixty degrees. Length and height sometimes nearly
equal, but in some specimens the length is one-fourth greater than height.
The margins in the basal half of the shell regularly rounded; in the upper
half of the valve anterior margin of the body is almost straight or very little
curved, while the posterior border of the body is entirely straight or even
slightly concave. The post-basal part of the shell is extended. The left valve,
which is only preserved in the specimen before me, is moderately convex
throughout the whole body. The umbo is somewhat more elevated; its ante-
rior slope is gentle, while the posterior descent is abrupt, meeting surface of
the posterior wing almost at right-angles, thus forming a sulcus by which
the rear wing is defined.

The hinge-line is straight from the anterior side of beak to the posterior ex-
tremity. Beak anterior, acute, prominent, inclined forward, and rising above
the cardinal 'line ; the umbonal margins form an acute angle of less than
sixty degrees. Front ear short, oblique, limited by a deep, but not sharply

'230 PALEONTOLOGY OF KENTUCKY.

defined sulcus. Terminal margin of the rear wing concave, and the cardinal
extremity acute.

The test is thick ; the left valve, in well preserved specimens, is covered by
numerous strong, simple, sharp, radiating striae, which are continuous from
the umbo to the margin ; intercalated radii are very seldom, but when they
exist they are finer than the balance. The radii are crossed by regular,
sharp, elevated, concentric lamellae, which, in well preserved specimens, are
produced into sub-tubular, spiniform extensions upon the rays. On the wings
the radii are less conspicuous, while the concentric lines of growth are there
more prominent and crowded. The specimen here described and figured meas-
ures in both height and length fifteen lines, and its hinge-line thirteen lines.

Formation and Locality. — Occurs in the Corniferous limestone of the Devonian formation at and
around the Falls of the Ohio.

INDEX TO GENERA AND SPECIES DESCRIBED.

PROTISTA.

PLATES.

Brachiospongia

digitata 35, 36

BRYOZOA.
Ptilodictya

hilli 35

BRACHIOPODA,
Ambocoelia

umbonata __ 17

. .nastrophia

internascens 32

Athyris

vittata. --- - 16

Atrypa

aspera 14

calvini - - - 32

ellipsoida -

reticularis. - 14, 15

reticularis, var. niagarensis 32

Camarella

congesta - - -

Centronella

glans-fagea - 31

Ghonetes

acutiradiata 18

subquadrata - - --

yandelliana 17, 31

Crania

bordeni --- , ..- 2

232 INDEX.

PLATES.

Cyrtia

exporrecta 27

exporrecta, var. arrecta 27, 32, 34

Cyrtina

crassa__ 13

hamiltoniae 13

hamiltoniae, var. recta 13

Discina

doria

grandis '.. , 3

Leiorhynchus

quadricostatus

Leptocoelia

hemispherica 1 32

Lingula

triangulata - 31

Meristella

nasuta _.. 15

unisulcata 15

Meristina

maria : 29

nitida %- - - - 33

Nucleospira

concinna . 32

elegans .- -

pisif ormis 33

Orthis

bif orata 29

borealis 34

elegantula 32

flabellum 34

goodwini 17

hybrida 32

livia 16, 17

linneyi r 34

INDEX. 233

PLATKS.

Orthis — Continued.

nisis 27

propinqua 16

rugaeplicata 27

subnodosa

vanuxemi ._ 16

Fentamerella

arata 13

papilionensis

thusnelda 31

Pentamerus

complanatus 27

globulosus _ .

knappi 28

knotti 32

knighti 29

littoni 27

nucleus 27, 33

nysius, var. crassicostus 28

nysius, var. tenuicostus

oblongus 33

oblongus, var. cylindricus _ _ 30

pergibbosus 29

uniplicatus 33

ventricosus _ 33

Productella

semiglobosa 26

subaculeata, var. cataracta 17

Rhynchonella

acinus — - - - 32, 26

bellaf orma 1 .

Carolina . -. - 13

gainesi - - - 31

increbescens 34

indianensis 33

louisvillensis . . 31

pisa 32

rugaecosta 32

saffordi - ._._-..,._. _.Tr ._,,_._,____ 27, 33

. SUK. — 30

234 INDEX.

PLATES.
Rhynchonella— Continued.

saft'ordi, var. depressa 33

Strickland! 29, 27

tenuistriata 17

tethys - 13, 31

Rhynchotreta

cuneata, var. americana 32

Spirifera

acuminata 8

arctisegmenta '. . . 12

atwaterana 9

byrnesi 10

conradana .... 7

crispa, var. simplex 17

davisi 12

divaricata 11, 12

dubia _ 33

duodenaria 12

euruteines 6

euruteines, var. f ornacula 6

foggi 32

gregaria 8, 10

grieri 9

hobbsi ... 10

knappiana 7

macconathii . _ 11

marionensis •

medialis 26

mucronata 31

oweni ._ 7

radiata 29

raricosta 17

rostellum 27, 29

sculptilis 31

segmenta . . . 13

varicosa , 10

Streptorhynchus

arctostriata 31

subplanus 29

tenuis .

INDEX. 235

PLATES.

Stricklandinia

louisvillensis 34

Strophodonta

demissa 33, 18

hemispherica 18

inequistriata 17

nacrea

perplana 18

plicata

prof unda 17, 29

striata

Strophomena

rhomboidalis (Devonian) 18

rhomboidalis (Silurian)

Terebratula

harmonia - 17

jucunda

lincklaeni 17

roemingeri _ . - ..- 16

Trematospira

hirsuta 16

helena 32

Tropidoleptus

carinatus - -- 17

Zygospira

kentuckiensis - 34

PTEROPODA.
Styliola

fissurella

Tentaculites

sialariformis 31

GASTEROPODA.
Bellerophon

leda . --- 17

236 INDEX.

PLATES.

Bucania

devonica _ - 26

Gallonema

bellatula -- 20

clarki 24

imitator 20

Cyclonema

cancellata - 20

multilira — 22

rugaelineata 33

Euomphalus

deceini — 21

sampsoni --- 21

Loxonema

hamiltoniae 31

hydraulicum 20

laeviusculum 22

rectistriatum -

Macrocheilus

carinatus - - - 20

Murchisonii

desiderata 26

petila _ 31

Platyceras

bucculentum 23

compressum 25

conicum 25

dumosum . - 23

dumosum, var. rarispinum 23

echinatum -- 31

erectum - .-.

milleri 25

nmltispinosum 25

rictum - -

symmetricum 23

thetis -

unguif orme

ventricosum 25

INDEX. 237

PLATBS.

Platyostoma

lineata 19, 21

lineata, var. callosa 21, 22, 25

niagarense 33

turbinata _ 21

turbinata, var. cochleata

Pleurotomaria

arabella . 26

casii 26

lucina

procteri 21

sulcomarginata 21

Polyphemopsis

louisvillae. 20

Strophostylus

varians — 22

Trochonema

f atua

rectilatera 20

yandellana 20

Turbo

shumardi 19, 22

CEPHALOPODA.

Gomphoceras

oviforme - 21

turbinif orme 21

Goniatites

discoideus - — -- 20

Lituites

marshi --- 30

Nautilus

maximus. . 24

238 INDEX.

LAMELLIBRANCHIATA.

PLATES.

Actinopteria

boydi 3

Aviculopecten

crassicostatus

f asciculatus 3

pecteniformis 3

princeps

Clinopistha

antiqua

striata 4

subnasuta 4

Conocardium

cuneus 5

Cypricardinia

cataracta 4

cylindrica 4

inflata, var. sub-equivalvis

Cypricardites

halli . 34

Glyptodesma

cancellata . 5

occidentals 3

Goniophora

truncata 4

Grammysia

gibbosa _ „ 4

Limoptera

cancellata 3, 4

Modiomorpha

affinis

alta 26

charlestownensis 5

concentrica 2

mytiloides

INDEX. 239

PLATES.

Nucula

herzeri _.

neda 5

niotica 5

Paracyclas

elliptica 2

elongata _ 2

lirata 2

octerlonii 31

ohioensis . - 6

Ptychodesma

knappianum - 2

Yoldia

valvulus - 4

PROTISTA.

FAGB.

Brachiospongia digitata - - - - 29

BRYOZOA

Ptilodictya Mill 30

BRACHIOPODA.

X

Ambocoelia nmbonata 86

Anastrophia internascens 47

Athyris vittata 87

Atrypa aspera 88

calvini __ ... 89

ellipsoida 90

reticularis 91

reticularis, var. niagarensis 92

Camarella congesta 48

Centronella glans-fagea . 153

Chonetes acutiradiata 66

snbquadrata . .-_ 67

yandelliana - 68

Crania bordeni 32

Cyrtia exporrecta - 93

exporrecta, var. arrecta 94

Cyrtina crassa - 95

hamiltoniae 96

hamiltoniae, var. recta 97

Discina doria 32

grandis 33

Leiorhynchus quadricostatus _ _ _ _ r ... r ......... , , . r , r . , . , , _ ..... r = 71

INDEX. 241

PAGE.

Leptocoelia hemispherica _ _ _• 152

Lingula triangulata 34

Meristella nasuta 98

unisulcata 99

Meristina maria 101

nitida. 102

Nucleospira concinna 103

elegans 104

pisiformis ] 04

Orthis biforata , _ _ _ 35

borealis 36

elegantula 37

flabellum 38

goodwini _ _ 39

hybrida 39

livia , 40

linneyi 41

nisis 42

propinqua 43

rugaeplicata 44

subnodosa 44

vanuxemi „ , 45

Pentamerella arata , . 49

papilionensis ... 50

thusnelda 61

Pentamerus complanatus 63

globulosus 64

knappi - 55

knighti _• 67

knotti - 66

littoni ,.__- . 58

nucleus 69

nysius, var. crassicostus 60

nysius, var. tenuicostus 60

oblongus 60

oblongus, var. cylindricus 61

pergibbosus : 62

uniplicatus 63

ventricosus 64

Prgductella semiglobosa ............ , . , , T , . .. . 7Q

GKOL. SUK. — 31

242 INDEX.

PAGE

Productella subaculeata, var. cataracta 69

Rhynchonella acinus 73

bellaf orma 73

Carolina. _ _. 75

gainesi 76

increbescens 83

indianensis 76

louisvillensis 77

pisa 78

rugaecosta 78

saffordi 79

saffordi, var. depressa 80

stricklandi 81

tenuistriata _ 82

tethys : 83

Rhynchotreta cuneata, var. americana 85

Spirif era acuminata 105

arctisegmenta 108

atwaterana 107

byrnesi 109

conradana 110

crispa, var. simplex 111

davisi , 112

divaricata 113

dubia .__ 115

dnodenaria 114

euruteines 115

eurnteines, var. fornacula 117

foggi _ 117

gregaria 119

grieri _ 120

hobbsi 121

knappiana 122

macconathii 123

marionensis . . _ 124

medialis.. 125

mucronata 126

oweni 126

radiata . _ 130

raricosta ,. .,.„„. 123

INDEX. 243

PAGE.

Spirifera rostellum " 129

sculptilis 132

segmenta 132

varicosa 134

Streptorhynchus arctostriata 140

subplanus 141

tenuis . _ . . 142

Stricklandinia louisvillensis 65

Strophodonta demissa 143

hemispherica 144

inequistriata 145

nacrea .., 146

perplana 147

plicata 149

profunda . 148

striata 149

Strophomena rhoraboidalis (Devonian) 150

rhomboidalis (Silurian) 151

Terebratula harmonia 154

jucunda. 154

lincklaeni 155

roemigeri - - 155

Trematospira hirsuta 136

helena 137

Tropidoleptus carinatus — 46

Zygospira kentuckiensis . 138

PTEROPODA,

Styliola fi ssurella - 157

Tentaculites scaliformis . 156

GASTEROPODA.

Bellerophon leda -- 158

Bucania devonica . 160

Callonema bellatula 175

clarki - 175

imitator . 176

244 INDEX.

Cyclonema cancellata ..................... _______ ..... ... .......... . . 187

multilira ____ ............ ... ..... ____________ ......... ___________ 188

rugaelineata ........ _________________ ____ ....... ________________ 187

Euomphalus decewi _____________________________ ..... _________________ 181

sampsoni ________________________ ..... . . ........... ______ ...... 182

Loxonema hamiltoniae ____ ...... _____________ ................. ________ 177

hydraulicum .......... _____ ..... . ____________ ........ ________ ._ 178

laeviusculum _________________________ .......... ________ ..... .. 178

rectistriatum ________________ . ................. _____ ......... .. 179

Macrocheilus carinatus ..... ________ ....... ........ ___________ _______ 180

Murchisonia desiderata ______ ..... _________ .......... ____ ........... _ . 169

petila ........... ____________ ..... _____________ ..... _____________ 170

Platyceras bucculentum . . ...... ._ ....... _______________ .............. 160

compressum ......... __________________ ....... __________________ 162

conicum ____________________________________ ...... _____________ 161

dumosum ................ ___________ ........ __________ ...... . _ _ 162

dumosum, var. rarispinum _________________ ....... _______________ 163

echinatum ........ ....... ___ ..... . ..... _ _ ....... ______________ 164

erectum ...... __________ ......... ___________________________ ..... 165

milleri ........ ___________ ........ . ..... _______________________ 166

multispinosum ...... ______ ..... _________________________ ..... . . 166

rictum . ..... _____________ ________________________________ ...... 166

symmetricum ... ..... __________________________________________ 167

thetis .............. _____________________________________________ 1 68

unguiforme _______________________________________________________ 168

ventricosum __________ _______________________ ........ ___________ 168

Platyostoma lineata ________________ . ... ...... ______________________ 183

lineata, var. callosa _____________________________________________ 184

niagarense ____________________ ..... ____________________ ' ______ . ____ 185

turbinata _________________ _____________________________________ 184

turbinata, var cochleata ______________________ ..... ______________ 185

Pleurotomaria arabella ........... _ ..... _____ ..... _____________________ 171

casii _______ ...... . . ...... _____________________________________ 171

lucina. ............ ____________ ..... _______ .. ____ . _____________ 172

procteri ____ ........ _ .......... .. ..... __________________________ 173

suJcomarginata _____________________ ....... ____________________ 174

Polyphemopsis louisvillae _______ ........ _______________________________ 180

Strophostylus varians ________________________________________________ 186

Trochonema f atua ...... .......... ________________________________ ____ 189

rectilatera ........ _______________ ...... . . ...... __________________ 189

yandellana .......... __________________________________________ 190

Turbo shumardi . 191

INDEX. 245
CEPHALOPODA.

PAGE

Gomphoceras oviforme _ 103

turbinif orme _. 194

Goniatites discoideus _ 194

Lituites marshi __ 195

Nautilus maximus 196

LAMELLIBRNACHIATA.

Actinopteria boydi _ 229

Aviculopecten crassicostatus 223

f asciculatus _ 224

pecteniformis. __ 225

princeps 225

Clinopistha antiqua 200

striata 200

subnasuta _. 199

Conocardium cuneus 203

Cypricardinia cataracta 204

cylindrica ._ 205

inflata, var. sub-equivalvis 206

Cypricardites halli 206

Glyptodesma cancellata 227

occidentale -.. 228

Goniophora truncata 214

Grammysia gibbosa ._ 208

Limoptera cancellata - - 198

Modiomorpha affinis 216

alta 217

charlestownensis. _ 218

concentrica 219

mytiloides 220

Nucula herzeri _ _ _ , 221

neda 222

niotica ' - 222

Paracyclas elliptica 209

elongata - - - 210

lirata 211

octerlonii : 212

ohioensis 213

Ptychodesma knappianum 201

Yoldia valvulus . 223

PAUGQNTQLOCR OF KENTUCKY.

77>

H rp-p T
lA i JTj A

OEl. AMO LITH. BV TOM TULEV.

LOUISVILLE LITH. CO.

PLATE L

CEPHALOPODA.
Belemnitella mucronata.

Fig. 16. View of the internal shell. Page 22

Sepia officiiialis. LINNE.

Fig. 12. View of a specimen. Page 22

a. Arms.

b. Tentacles.

c. Eyes.

Nautilus pompilius.

Fig. 24. View of the animal and shell, the latter sawed through

the middle. Page 22

a a. Air chambers.
b b. Septa.
c c. Siphuncle.

Goniatites henslowi.
Fig. 18. View of a specimen, the outer shell entirely removed. Page 22

CeratitCS IlOdoSUS. BRUGUIKRK.

Fig. 19. View of a specimen, outer shell entirely removed. Page 22

TurrilitCS COStatllS. LAMABK.

Fig. 2. Apertural view of a specimen. Pages 22 and 23

a. Apex.
a f . Spire.

b. (

c. < Sutures.

d. (

g. Aperture,

Bacilli tes ancepS- LAMAKK.

Fig. 1. View of the internal shell. Page 22

a. Aperture.

b. Septa.

c. Sutures.

PLATE I.

GASTEROPODA.

Triton COlTUgatuS. LAMARK.

Fig. 23. Longitudinal section of a specimen. The upper part of the

spire has been partitioned on0 many times successively. Page 23

Fascioloria tulipa.

Fig. 14. Apertural view of a specimen. Dextral. Page 23

a. Posterior canal.

b. Anterior canal.
d. Labrum.

FUSUS antiquus. MUELLER.

Fig. 15. Apertural view of a specimen. Sinistral. Page 23

a. Posterior canal.

b. Anterior canal,
f. Labrum.

Faludina listen. HANLEY-

Fig. 21. Apertural view of a specimen. Dextral. Page 23

a. Aperture, closed by operculum.

b. apex.

Ampullaria bolteniana. CHEMNITZ.
Fig. 10. Apertural view of a specimen. Sinistral. Page 2

Chiton squamosus.
Fig. 11. Dorsal view of a specimen. Page 22

Helix desertorum. FOSSKAL.
Fig. 13. View showing animal and manner of bearing shell. Page 22.

PLATE I.

PTEROPODA.

Hyalaea tridentata. LAMARK.
Fig. 4. Dorsal view of a specimen. Page 23

Conularia trentonensis. HALL.
Fig. 5. Front view of a specimen. Page 23

BRACHIOPODA.
Terebratula dorsata. SMKLTN.

Pig. 26. View of a dorsal valve. Page 24

a. Crura of the loop.

b. Loop.

c. Septum.

Fig. 22. Magnified section of shell of Terebratula. Page 24

Waldheimia australis. KINO.

Fig. 6. View of dorsal valve. Page 24

b. Loop.

1. Reflected portion of loop,
m. Abductor,
p. Hinge plate.
s. Septum.

Waldheimia australis. KING.

Fig. 25. View of ventral valve. Pages 23 and 24

a. Single abductor impression.

b. Foramen.

c. Deltidium.

d. Teeth.

r. Cardinal muscles.

v. Portion of the vent.

z. Attachment of pedicle sheath.

Spirifera striata.

Fig. 7. View of dorsal valve showing spiral cones. Page 24

Athyris concentrica.

Fig. 8. View of dorsal valve showing spiral cones. Page 24

Rhynchonella ptissacea.
Fig. 9. View of dorsal valve, showing spiral arm unrolled. Page 24

PLATE I.

LAMELLIBRANCHIATA.

Modiola lithophaga. LINNE.

Fig. 17. View of right and left valve. Page 25

a. Dorsal margin.

b. Anterior margin.

c. Posterior margin.

d. Posterior margin.

Cytherea chione. LINNK.

Fig. 3. View of left valve. Page 25

a Anterior abductor.
a. Posterior abductor.

e. Cardinal tooth.
d. Umbo.

h. Hinge linament.

f. Lunule.

p. Pallial impression.
t\ Lateral teeth.
s. Sinus.

Glycimeris siliqua. CHEMNITZ.

Fig. 20. View of a left valve. Page 25

a. Dorsal margin.

b. Anterior margin.

c. Posterior margin.

NOTE. — All figures on Plate I. are copied from "A Manual of the Mollusca.
A Treatise on Recent and Fossil Shells. By Dr. S. P. Woodward, A. L. S., F.
G. S., Second Edition. Lockwood and Co., London, England, 1871."

PLATE II.

Paracyclas elliptica.

Fig. 1-3. Right, left and cardinal view of specimen. Page 209

Paracyclas lirata.

Fig. 4. Left view of a specimen. Page 211

Fig. 5-7. Left, right and cardinal view of specimen.

Paracyclas elongata.

Fig. 8. Left view of a specimen. Page 210

Modiomorpha concentrica.

Fig. 9, 10, 14. Left view of specimen, showing variations in size and

ornamentation. Page 219

Fig. 11. 12. Right and profile view of specimen.

Crania bordeni.

Fig. 14. View of two specimens adhering to left valve of Modiomorpha

concentrica. Page 32

Ptychodesma knappianum.

Fig. 13. Profile view of a specimen. Page 201

Fig. 15. Left view of a specimen.

Fig. 16. Left view of a smaller individual.

Fig. 17. Right view of a specimen, showing striated ligamental area.

Fig. 18. View of left valve enlarged, showing striated ligamental area.

PALAEONTOLOGY OF KENTUCKY"

PLATE II.

15

"...

LOUISVILLE LITH.CO

PALAEONTOLOGY OF KENTUCKY.

LOUISVILLE LITH.CO.

PLATE III.

Aviculopecten pecteniformis.

Fig. 1. View of a left valve. Page 225

Actinopteria boydi.

Fig. 2. View of a left valve, showing surface ornamentation. Page 229

Discina grandis.

Fig. 3. Dorsal view of a specimen. Page 33

Aviculopecten fasciculatus.

Fig. 4. View of a left valve. Page 224

Glyptodesma occidentale.

Fig. 5. View of a left valve. Page 228

Limoptera cancellata.
Fig. 6-8. Left, right and cardinal view of specimen. Page 198

PLATE IV,

Cliiiopistha striata.
Fig. 1, 2. Right and left view of specimen Page 200

Cypricardinia cataracta.

Fig. 3. Left view of a specimen. Page 204

Yoldia ? valvulus.

Fig. 4, 5. Left view of two specimens. Page 223

Cliiiopistha subnasuta.
Fig. 6-8, 12. Left, cardinal, right and posterior view of specimen. Page 199

Cliiiopistha antiqua.
Fig. 9-11. Right, cardinal and left view of specimen. Page 200

Cypricardinia cylindrica.

Fig. 13-15. Left, cardinal and right view of specimen. Page 205

Grammysia gibbosa.

Fig. 16, 19, 20. Cardinal, left and posterior view of specimen. Page 208

Fig. 17. Right view of a specimen.

Fig. 18. Right view of a smaller specimen.

Goniophora truncata.

Fig. 21-23. Posterior, side and cardinal view of a specimen. Page 214

Limoptera cancellata.

Fig. 24. View of a young individual. Page 198

PALEONTOLOGY OF KENTUCKY.

PLATE IV.

7

"--.,

LOUISVILLE LITH. CO.

PALEONTOLOGY OF KENTUCKY.

PLATE Y.

.

LOUISVILLE LITH. CO.

PLATE V.

Glyptodesma cancellata.

Fig. 1. View of a left valve. Page 227

Nucula niotica.
Fig. 2-4. Anterior, left and cardinal view of a specimen. Page 222

Nucula neda.

Fig. 5, 6. Right and anterior view of a specimen. Page 222

Modiomorpha charlestowiiensis.

Fig. 7. Right view of a specimen. Page 218

Fig. 8, 9. Profile view of two specimens.

Conocardium cuneus.

Fig. 10, 11. Dorsal and ventral view of a specimen. Page 203

Fig. 12, 13, 15. Ventral views of three specimens, showing variations

in size and ornamentation.
Fig. 14. Lateral view, showing shield.
Fig. 16. Ventral view of a young specimen.
Fig. 17. Dorsal view of a young, very perfect specimen.
Fig. 18. Side view of a young specimen.
Fig. 19. Enlargement of a fragment of test, showing ornamentation.

Faracyclas ohioensis
Fig. 20. Right view of an average size specimen. Page 213

PLATE VI.

Spirifera euruteines.

Fig. 1-7, 9, 11-17. A series of specimens showing principal varieties of

form. Page 115

Fig. 21, 22. View of two specimens broken so as to show the spiral
cones.

Spirifera euruteines, var. fornacula.

Fig. 8, 10. Cardinal and ventral view of a large specimen. Page 117

Fig. 18, 19, 20. Dorsal, ventral and profile view of a small specimen.

PALEONTOLOGY OF KENTUCKY.

PLATE VI

LOUISVILLE LITH CO.

FAL/E ONTOLOGY OF KENTUCKY.

PLATE VII

DEL.ANO \.\tf. ft CHAS. STARCH.

LOUISVILLE LITH.

PLATE VII.

Spirifera oweni.

Fig. 1-4, 7. Dorsal, profile, cardinal, ventral and front view of speci-
men. Page 126

Fig. 5, 6. Lateral and dorsal view of a young specimen.

Fig. 8, 9, 10. View of three specimens broken so as to show the
spiral cones.

Spirifera conradana.

Fig. 11, 12. Dorsal and ventral view of a specimen. Page 110

Fig. 13. Dorsal view of a small specimen.

Spirifera knappiana.

Fig. 14. Ventral view of a specimen. Page 122

PLATE VIII.

Spirifera acuminata.

Fig. 1. Dorsal, ventral, profile, front and cardinal view of a speci-
men. Page 105
Fig. 6, 7, 8. Cardinal, ventral and dorsal view of an internal cast.

Spirifera gregaria.

Fig. 9-13. Ventral, dorsal, front, profile and cardinal view of a speci-
men. Page 119

PALEONTOLOGY OF KENTUCKY".

PLATE VIII

DEL. AND LITH. tY CHAS. STARCH.

LOUISVILLE LITH. CO.

PAUEONTOLOGY OF KENTUCKY.

PLATE IX

Ml. AND MTH.BYCHAS. STARCH.

LOUISVILLE LITH. CO.

PLATE IX.

Spirifera atwaterana.

Fig. 1-5. Dorsal, ventral, front, cardinal and profile view of a speci-
men. Page 107
Fig. 6, 7. Dorsal and ventral view of a smaller specimen.

Spirifera grieri.

Fig. 8-12. Cardinal, front, dorsal, profile and ventral view of a speci-
men. Page 120
Fig. 13, 14. Dorsal and profile view of a small specimen.

PLATE X,

Spirifera byrnesi.

Fig. 1-5. Dorsal, ventral, front, cardinal and profile view of a speci-
men. Page 109

Fig. 31-34, 36-39. A series of specimens, showing variety in form and
ornamentation.

Spirifera gregaria.

Fig. 6-10. Dorsal, ventral, front, cardinal and profile view of a speci-
men. Page 119

Spirifera varicosa.

Fig. 11-20, 23-25. A series of specimens showing variety in size, form

and ornamentation. Page 134

Spirifera hobbsi.

Fig. 21, 22. Dorsal and ventral view of a specimen. Page 121

Fig. 26-30. Dorsal, ventral, front, cardinal and lateral view of speci-
men.

Fig. 35, 40. Dorsal and ventral view of a specimen, showing extreme
extension of hinge-line.

PALEONTOLOGY OF KENTUCKY. '

PLATE X.

LOUISVILLE LITH. CO.

PALEONTOLOGY OF KENTUCKY.

UTH. BY CHAS. ST*RCK.

LOUISVILLE LITH. CO.

PLATE XI.

Spirifera mcconathii.

Fig. 1-6. Ventral, cardinal, dorsal, front and Drotile view of a speci-
men. Page 123

Spirifera divaricata.

Fig. 6-10. Dorsal, front, cardinal, ventral and profile view of a speci-
men. Page 113
Fig. 11. An enlargement of a portion of the test of a specimen.

PLATE XII.

Spirifera davisi.
Fig. 1-4. Dorsal, front, ventral and profile view of a specimen. Page 112

Spirifera divaricata.

Fig. 5-11. A series of specimens showing variations in form and size. Page 113

Spirifera duodenaria.

Fig. 12, 13, 16. Ventral, dorsal and profile view of a specimen. Page 114

Spirifera arctisegmenta.

Fig. 14, 15. Ventral and dorsal view of a specimen. Page 108

PALEONTOLOGY OF KENTUCKY

PLATE XII

OEL.UND LITH.8Y CHAS STAOCK

IOUISVILIE IITH. CO.

PALEONTOLOGY OF KENTUCKY.

PLATE XIIL.

LOUISVILLE LITH. CO.

PLATE XIII.

Rhynchonella tethys.

Fig. 25-33. A series of specimens showing variations in size and num-
ber of plications. Page 83

Spirifera segmenta.

Fig. 36-38. Dorsal, ventral and profile view of specimen. Page 132

Ryiichonella Carolina*
Fig. 1-3, 34, 35. A series of specimens showing variations in size. Page 75

Gyrtina hamiltoniae.

Fig. 4-12. A series of specimens showing variations in size and orna-
mentation. Page 90

Cyrtina hamiltoniae, var. recta.

Fig. 13. View of a small dorsal valve. Page 97

Fig. 14. Ventral view of a specimen.
Fig. 15. Profile view of a specimen.
Fig. 16. View of a larger dorsal valve.

Fentamerella arata.

Fig. 17-20. Dorsal, ventral, front and profile view of a specimen. Page 49

Cyrtina crassa.
Fig. 21-24. Ventral, cardinal, profile and dorsal view of a specimen. Page 95

PLATE XIV.

Atrypa aspera.

Fig. 1-5, 7-11. A series of specimens showing variations in form and

size. Page

Fig. 6. Interior of a ventral valve.

Atrypa reticularis.

Fig. 12-17, 19. A series of specimens showing variations in form and

size. Page 91

Fig. 18. Dorsal view of a specimen, broken so as to show spiral cones.
Fig. 20. Ventral view of a specimen, broken so as to show spiral cones.
Fig. 21. Side view of a specimen, broken so as to show spiral cones.
Fig. 22. View of a single spiral cone.
Fig. 23. View of interior of a ventral valve.

PALE ONTOLOGY OF KENTUCKY:

m

. : :

15

OtL. AND LITH. BY CHA9. 3TA R _

LOUISVlUt LITH. CO

PAUSONTOLOGYDF KENTUCKY.

PLATE XV.

-•' . -

PLATE XV.

Atrypa reticularis.

Fig. 1. Ventral view of a very rugose specimen. Page 91

Meristella iiasuta.

Fig. 2-5. Cardinal, dorsal, profile and ventral view of specimen. Page

Fig. 6-8. Cardinal, ventral and dorsal view of an interior cast.

Meristella unisulcata.
Fig. 9-16. A series of specimens showing variations in size and form. Page 99

PLATE XVI.

Orthis propinqua.
Pig. 1-3, 7-11. A series of specimens showing variations in size. Page 43

Orthis vanuxemi.

Fig. 4-6, 12, 12a-14. A series of specimens showing variation in size. Page 45

Trematospira hirsuta.

Fig. 15-19. Profile, dorsal, ventral, front and cardinal view of speci-
men. Page 136

Terebratula roemingeri.

Fig. 20-22. Profile, ventral and dorsal view of a specimen. Page 155

Orthis livia.

Fig, 23, 24. Dorsal and ventral view of a specimen. Page 40

Athyris vittata.

Fig. 25-29, 31, 32. A series of specimens showing variations in size

and ornamentation. Page 87

Fig. 30. Ventral valve broken to show position of spiral cones.

PALAEONTOLOGY OF KENTUCKY.

PLATE XVI

DEL. 8. LITH.BY CHAS. STARCK.

LOUISVILLE LITHOCR.CO.

PALEONTOLOGY OF KENTUCKY

PLATE XVII.

14

DEL » LITH.BY CHAS STARCK

LOUISVILLE LITHOGRAPHING CO.

PLATE XVII.

Terebratula harmonia
Pig. 1-4. Profile, dorsal, front and ventral view of a specimen. Page 154

Productella subaculeata, var. cataracta.

Fig. 5-8. Dorsal, ventral and front and transverse view of a speci-
men. Page 69
Fig. 9. Ventral view of a specimen, showing almost perfect spines.

Strophodonta inequistriata.

Fig. 10. Ventral valve of a specimen. Page 145

Fig. 11. An enlargement of a portion of the surface, showing inter-
calated striae.

Bellerophon leda.

Fig. 12. 13. Profile and side view of a specimen. Page 158

Tropidoleptus carinatus.

Fig. 14, 15. Dorsal and ventral view of a specimen. Page 46

Chonetes yandelliana.

Fig. 16-18. Ventral and dorsal view and transverse section of speci-
men. Page 68
Fig. 19. Dorsal view of a larger specimen.

Strophodonta profunda.

Fig. 20. Ventral valve of a specimen. Page 148

Fig. 21. An enlargement of a portion of the surface showing radiat-
ing striae.

Terebratula lincklaeni.

Fig. 22-24. Ventral, dorsal and profile views of a specimen. Page 155

Ambocoelia umbonata.

Fig. 25, 26. Dorsal and profile view of a specimen. Page 86

Rhynchonella tenuistriata.

Fig. 27, 28, 29. Ventral, dorsal and front view of a specimen. Page 82

Orthis goodwini.

Fig. 30-32. Dorsal, ventral and profile view of a specimen. Page 39

Orthis livia.
Fig. 33-35. Ventral, dorsal and profile view of a specimen. Page 40

Spirifera crispa, var. simplex.

Fig. 36, 37. Dorsal and ventral view of a specimen. Page 111

Spirifera raricosta.

Fig. 38-42. Profile, front, cardinal, ventral and dorsal view of a spe-
cimen. Page 128

PALEONTOLOGY OF KENTUCKY

PLATE XVIII

rt AND LITH.1V

PLATE XVIII.

Strophomena rhomboidalis.
Fig. 1-3. Ventral, dorsal and profile view of a specimen. Page 150

Strophodonta hemispherica.

Fig. 4-6. Ventral, dorsal and lateral view of specimen. Page 144

Fig. 7-9. Dorsal, ventral and lateral view of an internal cast.

Strophodonta demissa.

Fig. 10-15. A series of specimen showing variations in size. Page 143

Fig. 16. Lateral view of a specimen.

Strophodonta perplana.

Fig. 17. Ventral view of a specimen. Page 147

Ghonetes acutiradiata.

Fig. 18-20. Ventral, dorsal and profile view of a specimen. Page 66

PLATE XIX.

Turbo shumardi.

Fig. 1. Apertural view of a specimen. Page 191

Fig. 2. Dorsal view of a specimen.

Fig. 3. Vertical view of a specimen.

Fig. 4. Vertical view of a larger specimen.

Platyostoma lineata.

Fig. 5. Vertical view of a specimen. Page 183

Fig. 6. An enlargement of a portion of the test.
Fig. 7. Apertural view of a specimen.
Fig. 8. Dorsal view of a -specimen.

PALEONTOLOGY OF KENTUCKY.

PLATE XIX.

LOUISVILLE LITH TO

PALAEONTOLOGY OF KENTUCKY.

PLATE XX.

OEI.AN3 UTK ft? TO

LOUISVILLE LITH. CO.

PLATE XX

Polyphemopsis lo uisvillae.

Fig. 16-19. A series of specimen showing variations in size. Page 180

Macrocheilus carinatus.

Fig. 20-23. A series of specimen showing variations in size. Page 180

Trochonema rectilatera.

Fig. 1, 2. Apertural and dorsal view of a specimen. Page 189

Trochonema yandellana.

Fig. 3. Apertural view of a specimen. Page 190

•

Calloncma bellatula.

Fig. 4-7. A series of specimen showing variations in size and orna-
mentation. Page 175

Loxonema hydraulicum.
Fig. 8, 9. View of three specimen enclosed in matrix. Page 178

Cyclonema cancellata.
Fig. 10, 11. Dorsal and apertural view of a specimen. Page 187

Callonema imitator.
Fig. 12, 13. Vertical and apertural view of a specimen. Page 176

Goniatites discoideus.
Fig. 14, 15. Basal and profile view of a specimen. Page 194

PLATE XXI.

Euomphalus decewi.
Fig. 1, 2. Profile and upper surface view of a specimen. Page 181

Euomphalus sampsoni.

Fig. 3, 4. Profile and lateral view of a specimen. Page 182

Platyostoma turbinata.

Fig. 6, 6. Dorsal and vertical view of a specimen. Page 184

Platyostoma lineata.

Fig. 7, 8. Vertical and dorsal view of a specimen. Page 183

Pleurotomaria procteri.

Fig. 9, 10. Dorsal and vertical view of a specimen. Page 173

Fig. 13. Dorsal view of a small specimen.

Pleurotomaria sulcomarginata. •

Fig. 11, 12. Vertical and dorsal view of a specimen. Page 174

PAL-EONTOLOGY OF KENTUCKY

PLATE XXI.

DEL. a, tITH. 8Y CHAS. STARCK.

IOUISVIUE LITHOGRAPHING CO.

Platyostoma lineata, var. callosa.
Fig. 14. Lateral view of a specimen. Page 184

Gomphoceras turbiniforme.

Fig. 15, 16. View of two specimens showing variation in size. Page 194

Gomphoceras oviforme.

Fig. 17. Side view of a specimen. Page 193

Fig. 18. View of the aperture of a specimen.

PLATE XXII.

Turbo shumardi.

Fig. 1. Dorsal view of an internal cast of a specimen. Page 191

Fig. 2. Dorsal view of a perfect specimen, very large.

Bucania devonica.

Fig. 3, 4. Vertical and front view of a specimen Page 160

Cyclonema multilira.
Fig. 5. View of a gutta percha cast. Page 188

Strophostylus varians.

Fig. 6, 7. Dorsal and vertical view of a specimen. Page 186

Loxonema laeviusculum

Fig. 8. View of a somewhat distorted specimen. Page 178

Fig. 9. View of a more perfect specimen.

Platyostoma lineata var. callosa.
Fig. 10, 11. Side and summit view of a specimen. Page 184

PALEONTOLOGY OF KENTUCKY.

PLATE XXIL

;"L.8. LITH.BY CHAS. STARCH.

LOUISVILLE LITHOGRAPHING CO.

PALEONTOLOGY Of KENTUCKY.

PLATE XXIII.

v *

pv

le

DEL. & LITH. BY CHAS. STARCK

LOUISVILLE LITHOGRAPHING CO.

PLATE XXIII.

Platyceras dumosum.

Fig. 1-4. A series of specimen showing variations in size, distribu-
tion and condition of spines. Page 162
Fig. 5, 6. View of two specimen exfoliated, and showing spine bases.
Fig. 12. Vertical view of a young specimen.

Platyceras dumosum, var. rarispinum.

Fig. 7, 8. Dorsal and lateral view of a specimen. Page 163

Platyceras bucculentunu

Fig. 9, 11. Lateral view of two specimen, showing variation in size. Page 160

Platyceras symmetricum.
Fig. 10. Lateral view of a specimen. Page 167

PLATE XXIV.

Nautilus maximus*
Fig. 1. Side view of a specimen. Page 196

Callonema clarki.

•

Fig. 2. Summit view of a specimen. Page 175

Fig. 3. Side view of a specimen.
Fig. 4. Apertural view of a specimen.
Fig. 5. Side view of a smaller specimen.

PALEONTOLOGY OF KENTUCKY

PLATE XXIV.

DEL.& UTH.BYCHAS. STARCK

LOU1SVHJ.K LITHOGRAPHING CO.

PALEONTOLOGY OF KENTUCKY.

PLATE XXV.

DEL.& LITH SY CHAS. STARCK.

LOUISVILLE LITHOGRAPHING CO.

PLATE XXV.

Platyceras milleri.

Fig. 1. Anterior view of a specimen. Page 165

Platyceras conicum.

Fig. 2, 11. Dorsal view of two specimen, showing variation in size. Page 161

Platyceras bucculentum.

«

Fig. 3. Anterior view of a specimen. Page 160

Platyceras multispinosum.

Fig. 4. View of a cast of a very large specimen. Page 166

Platyostoma lineata, var. callosa.

Fig. 5-7. Apertural, side and dorsal view of a specimen. Page 184

Platyceras compressum.

Fig. 8, 9. Dorsal and posterior view of a specimen. Page 162

Platyceras ventricosum.

Fig. 6. Anterior view of a specimen. Page 168

PLATE XXVI.

Lingula triangulata.
Fig. 1. Ventral view of a specimen. Page 34

Spirifera medialis.

Fig. 2-5. Cardinal, ventral, dorsal and profile view of a specimen. Page 125

Rhynchonella acinus.

Fig. 6, 13, 14. Dorsal, profile and front view of a specimen. Page 73

Froductella semiglobosa.
Fig. 7. Ventral view of a specimen. Page 70

Murchisonia desiderata.

Fig. 8. View of an internal cast of a specimen, which is entirely cov-
ered by an incrusting coral, studded with somewhat irregularly
distributed tubercles. Page 169

Bucania devonica.

Fig. 9. View of an internal cast. Page 160

Modiomorpha alta.

Fig. 10. Left view of a specimen. Page 217

Pleurotomaria casii.

Fig. 11. Dorsal view of a specimen. Page 171

Pleurotomaria arabella.

Fig. 12. Apertural view of an internal cast retaining a small portion

of the test. Page 171

PALEONTOLOGY OF KENTUCKY.

PLATE XXVI

Dtl. &LITH.BY CHAS.3TARCK.

lOUISVIllE LITHOGRAPHING C.O.

PALEONTOLOGfTOF KENTUCKY.

PLATE XXVII.

m

'.v-.*'-

-••:

28

DCL.ANO UTH. »Y CHAS. STARCH

LOUISVILLE LITH.CO.

PLATE XXVII.

Orthis rugaeplicata.
Fig. 1-3. Dorsa*, profile and ventral view of a specimen. Page 44

Orthis nisis.

Fig. 4, 5. Ventral and profile view of a specimen. Page 42

Cyrtia exporrecta.

Fig. 6, 7, 8, 20. Dorsal, front, cardinal and profile view of specimen. Page 93

Rhynchonella stricklandi.

Fig. 9-11. Dorsal, profile and ventral view of a specimen. Page 81

Fentamerus littoni.

Fig. 12, 13. Dorsal and profile view of a specimen. Page 58

Pentamerus complanatus.

Fig. 14. Cardinal view of a specimen. Page 53

Fig. 15, 16. Dorsal view of two specimen, showing variations in size.

Spirifera rostellum.

Fig. 17-19. Dorsal, ventral and front view of a specimen. Page 129

Cyrtia exporreeta, var. arrecta.

Fig. 21. Profile view of a specimen. Page 94

Rhynchonella saffordi.

Fig. 22-24. Dorsal, front and profile view of a specimen. Page 79

Fentamerus nucleus.

Fig. 25-27. Front, profile and dorsal view of a specimen. Page 59

Fig. 28. An enlargement of a portion of surface of test.

PALEONTOLOGY OF KENTUCKY.

PLATE XXVIIi.

PLATE XXVIII.

Fentamerus knappi.

Pig. 1-4. Dorsal, ventral, profile and cardinal view of a specimen. Page 55

Fentamerus nysius, var. crass icostus.

Fig. 5-8. Profile, cardinal, dorsal and ventral view of a specimen. Page 60

PLATE XXIX.

Pentamerus knighti.

Fig. 1, 2. Dorsal and profile view of a specimen. Page 57

Fig. 17. Profile vie\v of an unusually large specimen.

Rhynchonella stricklandi.
Fig. 3-6. Dor»al, cardinal, profile and front view of a specimen. Page 81

Meristina maria.
Fig. 7-10. Dorsal, ventral, profile and front view of a specimen. Page 101

Streptorhynchus subplanus.

Fig. 11, 12. Profile and ventral view of a specimen. Page 141

Spirifera radiata.

Fig. 13-16. Dorsal, ventral, profile and cardinal view of a specimen. Page 130

Orthis biforata.

Fig. 18-22. Ventral, profile, dorsal, front and cardinal view of a

specimen Page 35

Pentamerus pergibbosus.
Fig. 23, 24. Profile and dorsal view of a specimen. Page 62

Spirifera rostellum.
Fig. 25. Dorsal view of a specimen. Page 129

Strophodonta profunda.

Fig. 26. Ventral view of a specimen. Page 148

PALEONTOLOGY OF KENTUCKY

PLATE XXIX

m

• \^~

r

DEL.&UTH.Br CHAS. STARCH.

PALEONTOLOGY OF KENTUCKY

PLATE XXX.

DEL.& LITH BY CHAS. STARCK

LOUISVILLE LITHOCHAPHING CO.

PLATE XXX.

r>

Lituites marshL
Fig. 1. Anterior view of a specimen. Page 195

Pentamerus oblongus, var. cylindricus

Fig. 2-4. Profile, dorsal and ventral view of a specimen. Page 61

PLATE XXXI.

Rhynchonella louisvillensis.
Fig. 1-4. Dorsal, ventral, front and profile view of a specimen. Page 77

Murchisonia petilla.

Fig. 5. View of an internal cast. Page 170

Rhynchonella gainesi.

Fig. 6, 7. Dorsal view of two specimens. Page 76

Fig. 8, 9. Front and ventral view of a specimen.

Spirifera mucronata.

Fig. 10, 11. Ventral and dorsal view of a specimen. Page 126

Tentaculites scalariformis.
Fig. 12. View of a specimen, enlarged xi. Page 156

Spirifera sculptilis.

Fig. 13. Ventral view of a valve. Page 132

Centronella glans-fagea.
Fig. 14-17. Front, pronies dorsal and ventral view of a specimen. 153

PALEONTOLOGY OF KENTUCKY.

PLATE XXXI,

DEL &LITH BY CHAS. STARCH

Faracyclas octerlonii.
Fig. 18. Left view of a specimen. Page 212

Chonetes yandelliana.

Fig. 19, 20. Ventral and profile view of a specimen. Page 68

Fig. 30. Transverse section of a specimen.

Platyceras echinatum.

Fig. 21. Side view of a specimen. Page 164

f

Rhynchonella tethys.
Fig. 22-25. Dorsal, profile, front and ventral view of a specimen. Page 83

Pentamerella thusnelda.

Fig. 26-28. Profile, dorsal and ventral view of a specimen. Page 51

Loxonema hamiltoniae.

Fig. 29. View of a rather perfect specimen. Page 177

Streptorhynchus arctostriata
Fig. 31-33. Cardinal, ventral and dorsal view of a specimen. Page 140

PLATE XXXII.

Nucleospira concinna.
Fig. 1-4. Dorsal, ventral, front and profile view of a specimen. Page 103

Atrypa reticularis, var. niagarensis.

Fig. 5-8. Profile, dorsal, front and ventral view of a specimen. Page 92

Fig. 44-47. Dorsal, ventral, profile and front view of a specimen, show-
ing variation in size.

Pentamerus knotti.

• .
Fig. 9-12. Dorsal, profile, ventral and front view of specimen. Page 5

Rhynchonella acinus.

Fig. 13-16. Dorsal, ventral, profile and front view of a specimen. Page 73

Anastrophia internascens.
Fig. 17-20. Dorsal, ventral, front and profile view of a specimen. Page 47

Leptocoelia hemispherica.

Fig. 21-23. Dorsal, ventral and profile view of a specimen. Page 152

Fig. 36-39. Profile, front, ventral and dorsal view of a larger speci-
men.

Rhynchonella pisa.

Fig. 24-27, Profile, dorsal, ventral and front view of a specimen. Page 78

PALEONTOLOGY OF KENTUCKY.

PLATE XXXII.

DEL.&tlTH.Br CHAS STARCK.

LOUISVILLE 1ITHOGRAPHING CO.

Spirifera foggi.

Fig. 28-31. Dorsal, front, ventral and profile view of a specimen. Page 117

Orthis hybrida.
Fig. 32-35. Dorsal, ventral, front and profile view of a specimen. Page 39

Trematospira helena.
Fig. 40-43. Dorsal, ventral, profile and front view of a specimen. Page 137

Rhynchonella rugaecosta.

Fig. 48-51. Dorsal, front, ventral and profile view of a specimen ; all

enlarged xi. Page 78

Orthis elegantula.

Fig. 52-57. A series of specimens showing variations in size. Page 37

Rhynchonella cuneata, var. americana.

Fig. 58, 59. Dorsal and ventral view of a specimen. Page 85

Fig. 62, 63. Front and profile view of a specimen.

Cyrtia exporrecta, var. arrecta.

Fig. 60, 61. Profile and cardinal view of a specimen. Page 94

Atrypa calvini.

Fig. 64-66. Profile, ventral and dorsal view of a specimen. Page 89

PLATE XXXIII.

Rhynchonella saffordi, var. depressa.
Fig. 1-3. Dorsal, ventral and profile view of a specimen. Page 80

Rhynchonella saffordi.

Fig. 4-6. Profile, dorsal and ventral view of a specimen. Page 79

Nucleospira pisiformis.

Fig. 7-9. Profile, dorsal and ventral view of a specimen. Page 104

Meristina nitida.

Fig. 10, 11. Dorsal and profile view of a specimen. Page 102

Fentamerus ventricosus.

Fig. 12-14. Dorsal, profile and ventral view of a specimen. Page 64

•

Fentamerus oblongus.

Fig. 15-17. Dorsal, profile and ventral view of a specimen. Page 60

Rhynchonella indianensis.

Fig. 18-20. Dorsal, ventral and profile view of a specimen. Page 76

PALEONTOLOGY OP KENTUCKY.

PLATE XXXIII,

'JCL.A I. 'TH.B1 r.HAS. STARCK

LOUISVIUE LITHOGRAPHING CO.

Cyclonema rugaeliiieata.
Fig. 21. Anterior view of a partly exfoliated specimen. Page 187

Strophodonta demissa.
Fig. 22. Ventral view of a specimen. Page 148

Spirifera dubia.
Fig. 23, 24. Dorsal and profile view of a specimen. Page 115

Fentamerus uniplicatus.

Fig. 25, 26. Dorsal view of a specimen Page 63

Pentamerus nucleus.
Fig. 27-29, 31-33. A series of specimens showing variation in size. Page 59

Flatyostoma niagarense.
Fig. 30. Vertical view of a young specimen. Page 185

PLATE XXXIV.

Cypricardites halli.
Fig. 1-6. A series of specimens showing variation in size and form. Page 206

Orthis linneyi.
Fig. 7-13. A series of specimens showing variation in size and form. Page 41

Orthis borealis.

Fig. 14-20. A series of specimens showing variation in size and form. Page 36

Zygospira kentuckiensis.
Fig. 21-25. A series of specimens showing variation in size and form. Page 138

Rhynchonella increbescens.
Fig. 26-29. Dorsal, ventral, front and profile view of a specimen. Page 83

Orthis flabellum,

Fig. 30. Dorsal view of a specimen. Page 38

Stricklandinia louisvillensis.
Fig. 31-34. Ventral, dorsal, profile and cardinal view of a specimen. Page 65

Cyrtia exporrecta, var. arrecta.

Fig. 35. Cardinal view of a specimen. Page 94

PALEONTOLOGY OP KENTUCKY.

PIRATE XXXIV.

PALEONTOLOGY OF KENTUCKY.

PLAT;- XXXV.

DEL.&. UTH BY CHAS. STARCH.

PLATE XXXV.

Ptilodictya hilli.

•>

Fig. 1. Transverse section of a specimen. Page 30

Fig. 2. View of an unusually large front.
Fig. 4. A portion of a frond enlarged.
Fig. 5.. View of a small, imperfect frond.

Brachiospongia digitata.

Fig. 3. Basal view of an unusually perfect specimen. Page 29

PLATE XXXVI.

Brachiospongia digitata.

Fig. 1. Front view of the specimen figured on Plate XXXV. Page 29

Fig. 2. Summit view of the same.

PALEONTOLOGY OF KENTUCKY.

PLATE XXXVI

DF.l « L! I H.B1 CHAS. STAKCK.

[NOTE.— The Monograph on Kentucky Fossil Sheila was published after the death of Mr. Nettelroth, and
was thus deprived of the advantage of the supervision and correction of proof by him.]

IR, IR, .A. T

PAGE. LINE.

17 10 ReadEozoon.

17 26 and 27 Read R. I. Murchison.

30 10 Read Polyzoa.

30 Under PTILODICTYA HILLI add ; Ptilodictya Mill, James.

The Palaeontologist, page 4, 1878. The original descrip-
tion of this species makes it unbranched and not digi-
tate. None of the figured specimens show any indication
of branching.

31 25 Read H. H. Hill.

32 Under reference to 27th Regents Report add ; The two dif-

ferent references and dates given here arise from the fact
that the plates illustrating the descriptions published in
1872, were not published until 1875 when the 27th Report
was issued. These plates are numbered "24th Report,"
and should always be included with it, though not pub-
lished until three years later.

33 19 Read p. 17.

37 17 Read vol. II.

38 7, 8, 9 Read FLA BELL ULUM.

39 3 From bottom, read vol. II.

41 After ORTHIS LITSWEYI, add James, not n. sp. ; also add

Orthis (?) Imneyl, James. The Palaeontologist, page 41,
1881.

42 8 From bottom, read Hall & Whitfield.

42 5 From bottom, read figs. 4-8.

43 17 Read 1867.

44 6 Read Hall & AVhitfield.

45 14 Read pp. 135, 136.

46 Add to TROPIDOLEPTUS, 10th Rept. State Cab. Nat. Hist.,

p. 151, 1857.

47 After line 6 from bottom, add, Anci.slropliia mternascens,

Hall, 28th Rept. State Cnb. Nat. Hist., p. 168, 1879.

II ERRATA.

PAGE. LINK.

49 7 From bottom, read 1841.

50 7 Prom bottom, read 1858.
53 J2 Read tenuicosta.

55 15 Read Hall & Whitlield.

58 18 Add 1859.

59 1 Read Hall & Whitiield.

60 1 Read Hall & Whitneld.
60 3 Read p. 185, 1872.

60 4 Read 4-7.

60 25 Read Hall & Whitlield.

60 4 From bottom, read Ibid Idem.

60 2 From bottom, add 1852.

68 Make line 13, 14 instead.

71 21 Read p. 168.

71 22 Read Atrypa (OrtMs) quadricostata.

75 3 Read pi. 54.

83 3 From bottom, read 1847.

83 5 From bottom, read Ryiwlwnella capax, Conrad., and add

below; Atrypa capax, Conrad. Jour. Phil. Acad. Sci.,
vol. 8, p. 264, 1842. Rhynclionella increbescens, Hall.
12th Report State Cab. Nat. Hist., p. 66, 1859. 13th
Report State Cab. Nat. Hist., p. 66, 1861. Rhynclio-
nella capax, Billings. Pal. Foss. Can., vol. 1, p. 142,
1862. RhyncJionella capax, Meek. Pal. Ohio, vol. 1,
p. 123, 1873.

84 25 Read 1876.

85 3 Read 1876.

85 Under Ambocoelia add; Ambocoelia, Hall. 13th Rep. N.

Y. State Cab. Nat, Hist., p. 71, 1860.
88 Add between line 8 and 9 from bottom, Atrypa spinosa

vel aspera.

93 11 From bottom, read trapezoidalis.

93 10 From bottom, read trapezoidalis.

103 10 From bottom, read pp. 25, 26.

104 7 From bottom, add p. 221 .

104 4 From bottom, read pp. 301, 302.

105 13 From bottom, add 1867.

108 10 (Note. — This reference is evidently to the extra or author's

edition of the paper published in the 1 Oth Annual Report,
with new pagination.)

ERRATA. Ill

PAGE. LINE.

110 5 Add 1867.

112 3 From bottom, read W. J. Davis.

113 4 Read 'oetiustus.
113 5 Add 1867.

120 23 Read 27 and 28.

124 23 Add vol. I, part 2.

126 Add to references of S. oweni ; Spirifer oweni. Hall. 10th

Rep. State Cab. Nat. Hist., p. 129, 1859.

128 5 Read p. 132.

129 11 Read Hall & Whitneld.

13 Read 1872.

14 Read 1875.
132 4 Read 1867.

7 From bottom, add p. 181,

135 25 Add 1867.

136 3 Read p. 168.

4 Read 14th Report, 1861.

138 Under Zygospira TcentucJdensis add ; Zygospira modesta,

var, IcentucMensis, James. The Palaeontologist, p. 7,

1878.
143 15 Read 1857.

16 Add vol. 1, part 2, and read 1858.

145 6 From bottom, read 1867.

147 15 Read 1857. Add to references StropJiodonta perplana, Hall.

Pal. New York, vol. 4, pp. 92, 98-101, 1867.
151 5 From bottom, after Leptocoelia add Leptocoelia concava,

Hall. JOth Report, Reg. State Cab. Nat. Hist., p. 107,

1857. Leptocoelia, Hall, 12th Rept. State Cab. Nat.

Hist., p. 32, 1859.

156 4 From bottom, read Tentaculities, 1879.

157 5 From bottom, read 1879.

158 6 From bottom, read 24th.

159 Under Bucania, add Pal. of New York, vol. 1, p. 32.
161 21 Read 1879.

163 7 From bottom, read 1879.

165 4 Read p. 32.
6 Read 1879.

166 7 From bottom, read 1879.

167 16 Read 1879.

168 5 Read 1879.

ERRATA.

PAGE.
168

LINE.

5

170

174

8

179

9

183

23

184

12

188

9

194

12

196

13

198

12

199

203

205
209

211
224
2-25

229

Plate

Plate

Plate

Plate

12

4
6

5

4
19

8

4

4
19
I.

VIII.
X.
XIII.

Plate XXV.
Plate XXVI.

Plate XXXI.
Plate XXXII.

Plate XXXIV.

Between line 4 and 3 from bottom add ; Platyceras ven-
tricosum, Hall. 12th Kept. State Cab. Nat. Hist., p. 17,
1859.

For petilla read petila.

From bottom, add p. 5<>, 1879.

Read p. 130.

Read 1879.

Add part 2, p. 23.

From bottom for pi. 12, read p. 36.

From bottom, add pi. 13, as var. Ohioensis.

Read 1879.

Read 1884.

After Cliiiopistha add ; Proc. Phila. Acad. Nat. Sci., p. 43,
1870.

From bottom, read pi. 11.

Read pp. 171, 172.

Read 1885.

Place (?) after Cypricardinia in references.

From bottom add ; & p. 95, fig. 18, 1885.

From bottom, add 1872.

Add 1885.

Read 1884.

Read 1884.

From bottom, add pp. 1-4, and read 1884.

Read 1884.

Description, transpose figs. 7 and'9.
Description, for fig. 1 read fig. 1-5.
For 32 in lower left hand corner read 36.
Change 23 on second line of figures from lower left hand

corner to 32.

In description for fig. 6, last line, read fig. 10.
Add 13 to upper, and 14 to lower one of the two unnumbered

figures.

Read Murchisonia petila for M. petilln.
Fig. 12, read enlarged twice.
After Rhyn. knotti, read p. 56.
Under Rhyn. rugaecosta, read enlarged twice.
For Rhynchonella cuneata, etc., read Rhynchotreta.
For Rhyn. increbescens, read R. capax.
For Orthis flabellum, read O. flabellulum.

//.

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