Welter — Kinderhook Faunal Studies. 21 



Remarks. This species resembles a diminutive A. um- 

 bonaia, but does not have the sharply defined cardinal area 

 which is characteristic of that species. It also resembles, 

 but to a less degree, A. miniUa, differing from it in its larger 

 size and its sharply impressed groove-like mesial sinus. 



Athyris lamellosa (Leveille). 



PI. IV. f. 8. 



An examination of specimens from various localities in the 

 Kinderhook group has led to the conclusion that Athyris han- 

 nibalensis and A. lamellosa are one and the same species. 

 From near Sulphur Springs, Mo., at the same locality or at 

 least from the same horizon at a nearby locality, from which 

 Swallow secured a part of his type specimens, good examples 

 of both forms have been examined, but associated with them 

 are specimens which might be either one or the other. The 

 form to which the name hannibalensis has been given is 

 smaller and rounder, while the more typical iamellosa is larger 

 and more transversel}' subelliptical in outline. In most of 

 the localities where A. hannibalensis has been found, it is 

 associated with individuals which are good typical forms of 

 A. lamellosa, and it is safe to say that the individuals usually 

 referred to A. hannibalensis are nothing more than young 

 specimens of A. lamellosa. 



Only a few individuals have been observed in the North- 

 view fauna, but these are all of the more typical, transversely 

 subelliptical A. lamellosa form, none of them being speci- 

 mens which might be referred to A. hannibalensis. 



Athyris ( Cleiothyris ? ) sp. 



PL IV. f. 11. 



There are, among the Northview fossils, several specimens 

 of a small shell too imperfect for certain identification, which 

 resemble Cleiothyris hirsuta from the Spergen Hill fauna 

 more closely than any other species. Some of the specimens 

 differ from this species in being more transversely subelliptical, 

 though others are as nearly circular as many of the Spergen 

 Hill specimens. The nature of the surface markings of these 

 shells cannot be satisfactorily determined, but they show 

 numerous, rather fine, concentric lamellae. The largest 



