1S70.] '^"^"^ [Wiiichell. 



DisciNA Capax? White (Proc. Bos. Soc. Nat. Hist.) From Blr.ck 

 Shale (Bed No. 6), Rockville, Ohio. 



These specimens resemble D. Lodensis in size and markings. They 

 differ in the more i^roininent and more excentric beak of the dor.<al valve. 

 The stria3 of D. Lodensis are also more regular and more sharply raised, 

 and it is a larger species. It is smaller and thinner than the types of D. 

 capax, bnt I hesitate to pronounce it distinct. 



DisciNA Gallaheei, Win. (Proc. A. N. S., Phil., July, 18G5). Col- 

 lected by Prof. Andrews, at Granville, Licking county, Ohio, — adherent 

 on a Spirifera; also, from near Shafer's, Penn. 



The Ohio specimens difter from D. Oallalieri only in size — being one- 

 half 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 vFOuld 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 D. Saffordi the foramen appears to be 

 similarly wanting, and it may have been equally slit-like during life. 



The Pennsylvania si^ecimens 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. 



Pkoducta 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 yellowish-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 showdng the ventral, and one both sides of the dorsal valve. Another 

 specimen exhibiting the exterior of a ventral valve, resembles the forms 

 named P. Slmmardiamis by Prof. Hall ; but this name is larobably a 

 synonym of P. concentrica. 



Producta semireticulata, Fleming. 



Collected by Rev. H. Herzer, at 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 ui)j)er Waverly); and in large and characteristic 

 sijecimens from near Shafer's, on Oil Creek, Venango county, Pemi. 



Producta Coopekensis? Swallow. 



From bed No. 4, Sciotoville, Ohio. 



