48 



valves of Sperifera and probably to other foreign objects. When it 

 is attached to the fenestrated expansions of Lyropora the fenestrates 

 are indicated in the dorsal valve. It is gregarious. 



Found in the Kaskaskia Group at Chester, Illinois, and now in 

 the collection of Wm, F. E. Gurley. 



Family PHOLADOPID.E. 



PHOLIDOrS GREENEI. 11. Sp. 



Plate 111. Fig. 10, dorsal vieuT; Fig. 77. inferior of same; Fig. 7.s. 

 profile view; Figs. 19, 20 and 21, the sonic en- 

 larged t trice natural size. 



This is a small species, collected by G. K. Greene in the washings 

 of the debris from the Hamilton Group, near Charlestown. Ind. In 

 general form it resembles Pholidops cinci n natiensis from the Hud- 

 son River Grouj:>. but this resemblance is only in the dorsal valve, 

 for P. cinci nnatiensis has a flat ventral valve, and a foramen at the 

 beak, that are not possessed by this species. This species possesses 

 the characters of the Devonian forms described by Prof. Hall from 

 New York, but minute comparisons are unnecessary. It is sufficient 

 to say that it is a well-marked and distinct species. 



It is in the collection of S. A. Miller. 



CLASS GASTROPODA. 

 Family OALYPTR .EID.F1 



PL AT YC ERAS 1XDIANENSE 11. Sp. 



Plate TV, Fig. ?, lateral view of the small specimen; Fit/. 8, dorsal 

 view; Fig. 9. aperture; Fig. 10, side view of a mature 

 shell with part of the side and sinuafed 

 end broken away. 



Species rather large. The back of the body whorl, from the apex 

 to the aperture, is sharply angular and strongly serrated. Toward 

 the apex the shell is laterally compressed, but it expands laterally 

 toward the aperture. The apex is sharply pointed. The shell makes 

 about one volution, in nearly the same plane, when the apex comes 

 in contact with the rapidly spreading body whorl. 



