centric striae usually best preserved in the spaces between the radiating
striae, often not very plain on the striae themselves.
Length of a dorsal valve, 17 mm.; breadth, 21 mm.; convexity,
5 to 6 mm. Length of a ventral valve, 21 mm.; breadth, 26 mm.;
convexity, 4 to 5 mm. Length of the only complete shell found, 18
mm.; breadth 23 mm.; convexity, 8 mm.; the relative elevation of the
beaks in this specimen may be understood by examining Fig. 21, of
Plate XIII.
Locality and position. Allen's and Soldiers' Home Quarries, Clinton
Group.
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GENUS MERISTELLA, Hall. .
XII. Meristella umbonata, Billings (sp.).
{Plate XIII, Figs. 2 a, b)
Shell elongate ovate, the sides forming a continuous curve from the
umbo of the ventral valve to the front margin, with the exception of a
very slight inward curve at the hinge extremities, not at all resembling
those of the Ohio forms of M. cylindrica ; front margin rounded.
Dorsal valve convex, greatest elevation at one third the distance
from the beak, thence obtusely rounded towards the beak which is con-
cealed by that of the ventral valve.
Vential valve strongly convex, forming a continuous curve from the
anterior margin to the beak, which is spirally incurved upon the beak
of the dorsal valve, which it more or less conceals. The ventral
valve considerably elevated above the beak of the dorsal, more so than
would be indicated by the figures accompanying this description.
Surface smooth, the concentric striae indistinct.
Length' of dorsal valve, 14 mm.; of ventral valve in the same
specimen, 17 mm.; breadth, 14 mm.; convexity, 12 mm. Length of
dorsal valve in a small specimen, 10 mm.; ventral valve, 12 mm.;
breadth, 8 mm.; convexity, 8 mm.
The first inclination was to place these specimens under Meristella
cylindrica, but several reasons will not permit this : the size of the
specimens is smaller, the elevation of the ventral valve is greater, the
length of the shell is relatively smaller as compared with its breadth,
and considered as young of M. cylindrica, their convexity is too great.
On the other hand they are of the same size and outline as M, umbo-
nata. Associated with the ordinary forms are also separated valves,
broadly ovate in outline and more nearly resembling those forms
described by Billings under the specific term Prinstana. Since the
writer is of the opinion that this species is only another form of M.
umbonata, its apparent occurrence in the same strata in Ohio with the
form just described, seems to him an additional proof of its identity.
Locality and position. Soldiers' Home Quarry, Clinton Limestone.
Specimens from this locality .were kindly loaned by Mr. George Cas-
well, of Dayton.
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GENUS TRIPLESIA, Hall.
XIII. Triplesia Ortoni, Meek.
Described in Ohio Pal. Vol. I.
Locality and position. Soldiers' Home and Centreville Quarries,
Clinton Group ; the upper * * shovel ends " are frequent in the upper
shaly courses of the Group.
GENUS
XIV. triplesiana, sp. n.
{Plate XIV, Figs. 13 a, b; and Fig, 14.)
The generic relations of the following shell I have been unable to
determine satisfactorily, although the specimens are in a moderately
good state of preservation. A specific name is merely suggested for
the local use of collectors, and a description appended to give notifica-
tion of at least the existence of such a shell. The specific name is
intended to suggest its similarity in appearance to certain very flat forms
of Triplesia Ortoni in which the cardinal area is not much developed.
Shell subquadrate, or rounded anteriorly and more oval in outline,
medium or larger in size; cardinal area scarcely developed, very
narrow, but apparently equalling the hinge line. Beaks approximate,
with about the same elevation, scarcely elevated above the hinge line,
not prominent.
One valve of the shell has a low mesial elevation of moderate
breadth, corresppnding to a mesial sinus on the other valve, which is
shallow but equally distinct. The comparative breadth of the mesial
fold and sinus, considering the general contour of the shell, although
suggesting Triplesia Ortoni, is dissimilar. In other respects it suggests
to me a strophomenoid shell.
Surface marked by broad, radiating, scarcely evident folds, and
similar concentric elevations of growth, in addition to which, very fine,
fibrous, radiating striae are visible in the more or less silicified shell.
Lateral margin meeting the hinge line at little more than an angle of
ninety degrees, rounded anteriorly, slightly projecting at the middle.
Length, 27 mm.; breadth, 29 mm.; convexity, 12 mm. Length of
another individual, 28 mm.; breadth, 30 mm.
Locality and position. Soldiers' Home Quarry, in the middle of thQ
Clinton Group.
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GENUS RHYNCHONELLA, Fisher.
XV. RHYNCHONELLA SCOBINA, Meek,
Described in Ohio Pal. Vol. I and II.
Locality and position. Soldiers* Home, Huffman, and Centreville
Quarries, Clinton Group; common.
GENUS ZYGOSPIRA, Hall.
XVI. Zygospira modesta. Say (sp.).
{Plate XIII, Fig. 6.)
Described in Ohio Pal. Vol. I., and mentioned as occurring in
the Clinton Group. I have seen no specimens which could be re-
ferred without doubt to this species unless it be a dorsal valve of the
following description.
Dorsal valve subquadrate orbicular ; beak not elevated ; marked by
about twenty simple plications ; with a shallow mesial sinus, occupied
by three plications, the middle plication larger, the lateral ones
smaller than the plications immediately adjacent.
Length, 7 mm. ; width scarcely larger.
Locality and position. Beavertown marl, Huffman's Quarry, Clinton
Group.
GENUS ATRYPA, Dalman.
XVII. Atrypa nodostriata, Hall.
{Plate XIII, Fig. 9.)
Shell described in Ohio Pal. Vol. II.
A small species of Atrypa referred here occurs sparingly, of the
following description.
Shell oval, marked by plications, branching near the middle of the
shell. Mesial sinus on the ventral valve plainly defined by the
bordering plication on each side, containing three to five plications.
Dorsal valve with mesial elevation, well defined by a more or less
sharp sinus on each side, which is more marked towards the beak.
Length, 11 mm.; breadth, 11 mm.; convexity, 6 mm.
Locality and position. Soldiers' Home, Clinton Group.
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GENUS EICHWALDIA, Billings.
XVIII. ElCHWALDIA RETICULATA, Hall.
(Plate XIII, Figs. 4 a, d.)
Shell broadly triangular ovate, gibbous, cardinal slopes flattened.
Ventral beak small, acute, flattened on the back, closely incurved,
the sinus extending from the beak to the anterior edge, broad, distinct.
Dorsal valve more convex, beak obtuse, strongly incurved, a low,
fairly defined mesial fold extending from the beak to the anterior
margin.
Surface covered by fine, hexagonal, reticulate markings, largest
along the antero-lateral slopes, and decreasing in size towards the sinus
and posterior regions. A small space near the ventral beak is destitute
of markings.
Length, 8 mm.; breadth, 8 mm.; convexity, 6 mm.
Locality and position. Fauvers' Quarry north of Dayton, Clinton
Group. Collection of Mr. E. M. Thresher.
Lamellibranchiata.
I. Pterinea brisa, * - - - - Hall.
II. Grammy sia Caswelli, - - - n. sp.
III. Cypricardites ferrugineum - Hall and Whitfield.
IV. Nucula minima, - - - - - n. sp.
The Lamellibranchiata of the Clinton Group of Ohio are but few
both in the number of species and in the frequency of their occurrence.
Pterinea brisa, if correctly identified, adds another link connecting
this formation with the Niagara Group of the West. It occurs also at
Waldron, Indiana, and Bridgeport, Illinois.
genus pterinea, Goldfuss.
I. Pterinea brisa. Hall.
{Plate XIII. Figs. 14 a, b.)
Left valve alone found. Body of the shell obliquely sub-ovate,
extremely inequilateral ; anterior wing moderately extended ; sinuate
at its junction with the body ; posterior wing acutely extended a little
beyond the posterior extremity of the shell; umbo prominent, beak
rising a little above the hinge line, muscular impression in. right valve
unknown from want of specimens.
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92 BULLETIN OF THE LABORATORIES
Surface marked by strong, radiating striae, and less conspicuous
concentric striae.
The intercalation of radiating striae in some cases gives rise to an
appearance similar to the dentations and groovings figured in the
Indiana reports, but not identical with them. The concentric striae
also are not so prominent. The crystallized character of our speci-
mens will, perhaps, account in part for these discrepancies. Fig. 14 ^
represents a specimen with fewer radiating striae, referred here.
Length, 16-17 mm.; l^eight, lo-ii mm.; convexity of the left valve,
about 2 mm.
Locality and position. Soldiers' Home Quarries, Clinton Group.
GENUS GRAMMYSIA, De Verneuil.
II. Grammysia Caswelli, sp, n.
{Plate XIV, Figs. 12 a, b.)
Shell small, transversely sub-ovate; umbonal regions gibbous, an-
terior regions likewise; height at the be^ks equalling about five-eights
of the length. Anterior end sloping abruptly from the beaks above,
with a distinctly concave outline, to the lower end of the lunule, where
it is met by the rounding base, forming more or less an angle at their
junction; base forming a broad semi -elliptic curve; posterior end
more compressed, the specimen at hand being too imperfect to de-
termine whether it gaps at this extremity, although it is presumed to
do so a little from the curvature of the better preserved valve ; pos-
terior end rounded, then curving upward and quite rapidly forward
almost merging into the hinge line.
Cardinal margin indistinctly preserved, judged to be nearly hori-
zontal, slightly concave in outline, and inflected along its entire length,
forming a well defined escutcheon ; lunule distinct, with an ob-ovate
oudine, quite deep. Beaks prominent, strongly incurved, obliquely
to the hinge, directed a little forwards, posterior umbonal slopes prom-
inently, yet rather broadly rounded.
Surface ornamented in the cast by well-defined concentric ridges
and furrows, these in the specimen at hand crossed by fine parallel
lines, almost vertical, directed a littie backwards, and which may be
accidental rather than a special feature of the shell. Ridges strongest
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OF DENISON UNIVERSITY. 93
anteriorly, becoming less distinct posteriorly. A portion of the shell
where preserved shows the ridges far less defined than on the cast.
Length, 37 mm.; height, 25 mm.; convexity, 25 mm.
Locality and position. Soldiers' Home, Clinton Group. Collection
of Mr. Geo. Caswell.
GENUS CYPRICARDITES, Conrad.
III. Cypricardites ferrugineum, HaU and Whitfield.
Species described in Ohio Pal. Vol. II.
Locality oHd position. Wilmington, CHnton County, Ohio, Clinton
Group. To my knowledge not found elsewhere.
GENUS NUCULA, Lamarck.
IV. NuCULA MINIMA, Sp. n.
{Plate XIV, Figs. 8 a, b, c.)
Shell (presumably the cast) very small, ovoid, gibbous above the
middle towards the beaks, outline curving to the base and posterior
extremity, anteriorly curving more rapidly to the beaks above. Beaks,
near the anterior extremity of the shell, incurved and inclined for-
wards. Hinge line at one-third the distance from the beak to its pos-
terior extremity supplied on each side with a narrow fold, directed
backwards, making a small angle with the hinge line, and vanishing at
one-third the distance from the posterior extremity in the depressed re-
gions formed by the raised postero-umbonal regions.
Near the beak on each valve are three to four radiating grooves,
which are characteristic of this species and are evident under the mi-
croscope.
In addition to these grooves are three more or less clearly defined
pits, one being placed in the anterior groove near the beak, and the
two others in the second groove, one on each side, and at a greater
distance from the beak. Along the hinge line, anterior to the beaks,
are two or three more or less distinct crenulations, which appear a little
like plications originating in the lunule near the beak and becoming
more distinct at the hinge line.
Length, 2 mm.; height, 1.4 mm.; convexity, i mm.
Locality and position. Beavertown marl, Huffman's Quarry; not
found elsewhere in the Clinton Group. Associated with many other
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94 BULLETIN OF THE LABORATORIES
minute forms, apparently chiefly in the form of casts, among these a
number of gasteropoda.
Gasteropoda.
I. Cyclonema bilix, . . . Conrad (sp.).
II. Trochonema nana, . . . . . n. sp.
III. Raphistoma affinis, . . . . n. sp.
IV. Pleurotomaria inexpectans, . Hall and Whitfield.
V. Cyclora alta, . . . . . n. sp.
VI. Strophostylus cyclostomus, .... Hall.
VII. Platyostoma Niagarense, . . . Hall.
VIII. Bucania exigua, . . . . . n. sp.
IX. Bellerophon fistello-striatus, . . . n. sp.
The Gasteropoda of the Clinton Group, identified with previously
described forms, are too few to form any great basis of comparison,
stratigraphically. Cyclonema bilix ranges from the Lower Silurian into
the Upper. Strophostylus cyclostomus is found also at Waldron, Indi-
ana. Platyostoma Niagarense differs in size and expansion at the ap-
erture from typical specimens, but its connection with them seems
undoubted. At any rate its deviation from the typical forms is far
less than the var. tngonostoma of Meek, and all these forms are typi-
cal of the Niagara.
GENUS CYCLONEMA, Hall.
I. Cyclonema bilix, Conrad (sp. ).
Shell described from the Lower Silurian in Ohio Pal. Vol. I.
Locality and position. Centre ville and Soldiers' Home Quarries,
frequent in the upper courses of the Clinton Group.
genus trochonema, Salter. |
II. Trochonema nana, sp. n. '
{Plate XIV, Fig. i6.)
Shell oblong, the height about twice the breadth, in the specimen
figured the carina being a little more prominent than is there indicated.
Volutions about three, increasing rapidly in size, the last disproportion-
ately so, forming the larger bulk of the shell, almost equaling two-
thirds the height. Shell thin ; it is impossible to trace the suture line,
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OF DENISON UNIVERSITY. 95
but there is a carina where the volutions may be supposed to meet, this
carina is distinctly grooved along the latter half of the last volution
where it approaches the aperture of the shell ; above the carina is a
low shallow groove which in the last volution spreads so as to cover
the entire volution. Surface smooth. Shell probably in the form of
a cast.
Height, 3 mm.; breadth, 1.5 mm.; height of aperture, .9 mm. (?)
breadth of aperture, .35 mm. (?) above, narrowing to .23 mm. (?)
below. The measurements given for the aperture are liable to
error, although there seem to be slight grooves and elevations at the
close of the last volution, which look like an elongated aperture.
Locality and position. Beavertown marl, Huffman's Quarry, Clin-
ton Group. (Name signifying dwarf. )
GENUS RAPHISTOMA, Hall.
ni. Raphistowa affinis, sp. n.
{Plate XIV, Fig. i8.)
Shell lenticular ; breadth a little more than twice the height ; con-
vexity moderate above, equally so below ; volutions varying from two
and a half to three and a half, with a moderate slope above, coinci-
dent with that of the spire ; the last volution sharply carinate around
the periphery, convex below, being more so at the umbilicus into
which the slope is abrupt ; suture distinct, forming a small groove
between the volutions ; umbilicus as wide as the outer volution ; the
last volution becoming transversely rhomboidal, the aperture itself not
being preserved, the breadth about three times the height. Surface
apparently smooth.
This species is almost in every respect identical with forms of J^.
lenticularis as known to me from the Lower Silurian formations. It
is however a much smaller shell, with less numerous volutions, and
apparently a distinct form.
Breadth of largest specimen, 7 mm.; height, 3 mm.; breadth of
the end of the last volution, 3 mm.; height, 1.2 mm.; aperture not
preserved.
Locality and position. Beavertown marl, Huffman's Quarry, Clinton
Group. (Name signifying related, the shell being closely allied to the
well known species, R. lenticularis.)
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GENUS PLEUROTOMARIA, De France.
IV. PLEUROTOMARIA iNEXPECTANS, Hall and Whitfield.
Shell described in Ohio Pal. Vol. II.
Locality and position. Iron ore beds of Clinton County, Clinton
Group.
GENUS CYCLORA, Hall.
V. Cyclora alta, sp. n.
(Plate XIV, Figs. iT a, b.)
Shell very small, conoid subglobose; spire varying from two-thirds
to slightly more than the diameter of the last volution ; volutions three
or four, increasing in size rapidly, but evenly ; the last volution not so
disproportionate in size to the rest of the shell as compared with the
species . so far described ; suture deep ; surface smooth ; umbilicus
small ; aperture circular.
Height of largest specimen seen, 4 mm.; breadth, 3. 5 mm. Height
of a specimen of the usual size, 2 mm.; breadth, 2.75 mm. From
this varying to specimens only i mm. broad.
This shell differs from the species of Cyclora so far described in its
greater size, greater elevation of the spire, and the more regular in-
crease of its volutions. Its general form approaches that of the
closely related genus Holopea. Since the chief distinction, however,
of the first genus is its diminutive size, it may be safe to refer to it
also the specimens here described.
Locality and position. Beavertown marl, Huffman's Quarry, Clinton
Group; not scarce (Name intended to suggest the height of the
spire, as compared with other species of this genus.)
GENUS STROPHOSTYLUS, Hall.
VI. Strophostylus cyclostomus. Hall.
{Plate XIV, Fig. 15.)
Shell transversely broad-oval. Spire moderately elevated ; volu-
tions in the specimen figured, three, a fourth having broken away;
the last .volution by far the largest, ventricose. Aperture not fully
exposed, oblique to the axis, subcircular.
Surface marked by shallow, broad striae and closer, finer striations
crossing the volutions obliquely and in a direction opposed to them.
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Diameter of volutions, measured in a plane vertical to the shell and
passing through the aperture, 6, 17, and 44 mm.; elevation of the
second and third volutions less than half the last.
The character and direction of the shell aperture, the relative size
and position of the volutions seem to leave no doubt as to the identity
of the specimen, and will at the same time serve to distinguish it from
any other species of gasteropod found in Ohio.
Locality and position. Soldiers' Home Quarry, Clinton Group.
GENUS PLATYOSTOMA, Conrad.
VII. Platvostoma Niagarense, HalL
{Plate XIII, Figs, 22 a, b; and Figs. 3 a, d.)
Shell ovoid, volutions three to four, the last much increased in
size, spire elevated above the plane of the outer volution, about one
sixth of the height of the shell.
Apex minute, expanding symmetrically as far as the outer volution,
which is ventricose, and somewhat straightened at the aperture, so as
not to maintain the curvature of the coil ; in one specimen marked on
the upper and lower side by a groove along which the striae are abrupt-
ly bent ; peristome undulated.
Surface marked by fine undulating striae of growth, cancellated by
finer revolving striae.
The specimens referred here are smaller in size than typical forms
of this species from western localities, and they differ from them in the
tendency for the last volution to lessen its rate of curvature and be-
come somewhat straightened as it approaches the aperture. This
straightened appearance is in part due to the slight expansion of the
lip at the aperture. Nevertheless these variances seem too slight to
give rise to any separation from the typical form under a new specific
name.
Height of shell, 2 1 mm. ; elevation of the first three volutions
above the plane of the last, 3.2 mm.; greatest diameter (passing
through the aperture), 26 mm.; diameter vertical to the same, 17 mm.;
diameter of the second and third coils, 2.6 and 7 mm.
Locality and position. Brown's Quarry, New Carlisle, Clinton
Group, kindly loaned from the collections of the Ohio State Universi-
ty, by Prof. Edward Orton.
In the Soldiers' Home Quarries occur specimens which have usu^-
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98 BULLETIN OF THE LABORATORIES
ly been referred to Holopea, both by collectors and writers on geology.
They consist for the most part of the upper three, or three and a half
volutions of a shell which seems identical with the form just described.
The character of the volutions and surface striations are the same; the
last volution is also expanded at the aperture, giving greater distinct-
ness to the lip, and having the same straightening effect on the curva-
ture of the shell at this point.
In the New CarHsle specimens, however, the upper side of the last
third of the last volution is flattened above and quite evenly rounded
on the sides, forming in this way a line of elevation along the upper
side of the volution, where the gradual curvature of the sides meets
the flattened portion above. In the Soldiers' Home specimen which
is best preserved, there is no flattening along the upper plane of this
last volution, but instead, there is an even curvature from the suture
to the lower side, an elevation being thus formed at the umbilicus into
which the side of the lower third of the volution bends abruptly.
The aperture of this specimen, therefore, is oblique to a ver-
tical diameter of the shell, whereas, in the New Carlisle speci-
mens the aperture seems to have its greatest diameter vertical
to the shell. Other forms, however, occur at the Soldiers' Home,
among which are some with deep sutures and less oblique apertures ;
some quite similar to the New Carlisle specimens, but much smaller;
a specimen with its coils arranged somewhat like P. piebium, but only
half its size ( Fig. 3 b. ); and a specimen varying to the opposite ex-
treme, with the last volution extremely ventricose, the upper vo-
lution only moderately raised, the part towards the aperture, however,
being lacking (Fig. 3a). All the forms from the Soldiers' Home
differ from the New Carlisle specimens, however, in their smaller size,
the New Carlisle specimens differing in turn from the typical western
forms chiefly in their smaller size. All these Clinton forms differ
from the western in the slight expansion of the lip at the aperture and
the straightened appearance of th^ volutions at this point, the rate of
curvature decreasing.
Specimens last described, at Soldiers' Home Quarries, Clinton
Group.
(The variations here indicated will be carefully figured in the next
paper.)
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GENUS BUCANIA, Hall.
VIII. BUCANIA EXIGUA, Sp. ft.
{Plate XIII, Figs. 18 В«, ^, c, d.)
Number of volutions not known, the last alone visible, increasing
rapidly in size- and expanding at the aperture; the exact character of
the aperture not known from want of preservation, but is presumed to
be similar to that of B. bilobatus. The outer volution rounded on the
dorsum at its origin, a mesial carina gradually developing toward the
aperture near which it becomes quite distinct, in some individuals, de-
cidedly so. From this carina the sides slope evenly to the umbili-
cus, which they enter with a sudden curve, forming a low, indistinct,
lateral carina, by the increase of curvature. Umbilicus apparently
closed, the last volution alone being visible in the specimens examined.
Surface of the cast smooth, traces of the original shell, however, seem
to remain in a few spots, indicating a system of striae curving from the
mesial carina obliquely backwards, these apparently crossed by other
striations. The usual form of the cast, however, is smooth, the shell
being entirely removed.
Measurements, on account of the imperfect preservation of the shell
towards the aperture, are of little value, still the following will serve to
give a general idea of the proportions of the shell. Greatest diame-
ter of the typical specimen (Plate XIII, Figs, a, b. ), 9 mm.; diameter
at right angles to this, 6.2 mm.; diameter of last volution at the
point where it becomes visible, 3.5 mm.; broadest part of volution
preserved, 7 mm. From this they vary in size from specimens which