1S70.] 
249 
[Winch ell. 
Discina Capax? White (Proc. Bos. Soc. Nat. Hist.) From Black 
Shale (Bed No. 6), Rockville, Ohio. 
These specimens resemble D. Lodensis in size and markings. They 
differ in the more prominent and more excentric beak of the dorsal valve. 
The strise of I). Lodensis are also more regular and more sharply raised, 
and it is a larger species. It is smaller and thinner than the types of I). 
capax , hut I hesitate to pronounce it distinct. 
Discina Gallaheri, Win. (Proc. A. N. S., Phil., July, 1885). Col¬ 
lected by Prof. Andrews, at Granville, Licking county, Ohio,—adherent 
on a Spirifera; also, from near Shafer’s, Penn. 
The Ohio specimens differ from D. Gallaheri only in size—being one- 
lialf the diameter, or less. The indentation of the dorsal valve is lenticu¬ 
lar in outline, and extends nearly from the posterior margin to the centre 
of the valve. Along the middle of the indentation on the inside is a rib¬ 
bon-shaped impression, bounded by a sharp, elevated ridge on each side, 
and divided by a similar, parallel ridge running along the middle of the 
impression. Each portion of this impression is marked by extremely del¬ 
icate, raised, transverse lines, which would seem to indicate that the im¬ 
pressions are not the foramen, but a portion of the shell. The foramen 
may have been a delicate slit occupying the place of the median ridge di¬ 
viding the two impressions. In I). Saffordi the foramen appears to be 
similarly wanting, and it may have been equally slit-like during life. 
The Pennsylvania specimens are mere casts of the non-perforate valve, 
slightly oval in outline, with irregular, concentric wrinkles, a sub-central 
beak elevated one-third the smaller diameter of the valve. One of the 
three casts bears apparently the impressions of the ribs of some costate 
shell, suggesting that this individual, like the Ohio specimens, may have 
been parasitic. The larger of these casts are fourteen-sixteenths by eleven- 
sixteenths of an inch in diameter. 
Producta concentrica, Hall (Iowa Geol. Rep. 517, pi. vii, fig. 3; 
10 Rep. N. Y. Regents, 180; see also, Winchell, Proc. A. N. S., Phil., 
July, 1865, p. 115). From yellowisli-brown calcareo-argillaceous beds, 
and from calcareo-silicious shales of Tennessee. Also, from Sciotoville, 
Ohio. 
The Tennessee collection contains one specimen showing both valves, 
one showing the ventral, and one both sides of the dorsal valve. Another 
specimen .exhibiting the exterior of a ventral valve, resembles the forms 
named P. 8'humar dianus by Prof. Hall; but this name is probably a 
synonym of P. concentrica. 
Producta semireticulata, Fleming. 
Collected by Rev. JI. Herzer, af Newark, Licking county, Ohio ; by 
Prof. E. Andrews, at Sciotoville (where it is abundant); from bed No. 5, 
Rockville ; from a point 2% miles west of “Cincinnati Furnace,” Vinton 
county, Ohio (in the upper Waverly); and in large and characteristic 
specimens from near Shafer’s, on Oil Creek, Venango county, Penn. 
Producta Cooperensis? Swallow. 
From bed No. 4, Sciotoville, Ohio. 
