OF DENISON UNIVERSITY. 
55 
lateral margins uniformly rounded. Right (?) valve moderately con- 
vex, hinge four-fifths the greatest length; beak nearly central; ante- 
rior wing small, ill-defined ; posterior wing larger, separated from the 
body by an oblique plane surface, rather flat ; no indications of a bys- 
sal sinus. Surface finely cancellated by uniform, high, regular radi- 
ating and concentric ridges, the latter sub-imbricating. There is little 
to determine which valve our single specimen represents, it may quite 
possibly prove to be a left valve. There is some resemblance to small 
specimens of L. orbiculatus. The most that can be said is that our 
shell possesses a decidedly Devonian aspect. Nodule layer at Moot’s 
run. 
Linatulina {?) ohioensis, sp. n. 
(Plate II, Fig. 20; Plate III, Fig. lo.) 
Shell of moderate size, obliquely and rather narrowly oval ; height 
over one-fifth greater than length; hinge line very short ; surface with 
distant, irregular furrows. Left valve moderately convex near the 
beak, elsewhere quite flat, with hinge line equal to about one-half the 
greatest length ; valve not very oblique, umbonal ridges meeting at the 
beak at less than a right angle, beak somewhat acute; anterior ear 
well-defined, but small, rounded and separated from the body of the 
valve by an abrupt descent, its margin concavely sinuated below ; pos- 
terior ear very small and obtuse. The posterior margin makes a broad 
curve which is straightened above, but curves more* rapidly in passing 
into the very convex front outline, d'he valve is marked by about 20 
distant and very irregular narrow and deep radiating striae and folds. 
Right valve very oblique and short, hinge line relatively longer, pos- 
terior margin straight, making an angle with the hinge of about 130°; 
posterior angle produced ; anterior ear small, convex, projecting, sep- 
arated from the valve by a profound acute byssal sinus; marked by 
about four or five distinct costae ; markings of the body as in the left 
valve. Evidently the shell was quite inequivalve. , 
Height of perfect left valve 20 (23) mm; lenght 15 (18) mm ; 
hinge 9 (8) mm; height of right valve 12 mm; lenght 10 mm (?); 
hinge 8 mm. 
A number of specimens have been secured only one of which, 
unfortunately, was a right valve. The shell is so thin as to make it 
