Merriam.] 



T) -ia ssic Ichthyoptet "ygia . 



67 



" The Atractites beds . . — These beds form the middle division 

 of the Hosselkus limestone; they are very hard and siliceous, and 

 while fossils are very numerous it is almost impossible to get out 

 good specimens. The thickness of these beds is about 100 feet, 

 but this is often seemingly increased by faulting. The rock is 

 cut through in several directions by joints, and the weathering of 

 the strata along these lines of weakness has given a rugged 

 outline to the ridges, of which the Atractites beds usually form 

 the top. 



"At the locality three miles northeast of Madison's ranch the 

 following fossils were collected from this horizon : 

 Polycyclus conf. henseli Oppel. 

 Trachyceras (like Tirolites in youth). 



conf. aon, Muenster. 

 Tropitcs subbullatus, Hauer. 



" sp. (with narrow coil) . 



sp. (with high- ribbed whorl). 



" satumus, Dittmar. 

 Halorites conf. ramsaueri, Gabb. 

 Eutomoceras sandlengense , Hauer. 

 Eatomocrras sp. 

 Acrochordiceras sp. 

 Lecamte* sp. 

 Arcestes, sp. 



Nautilus triadicus, Mojsisovies. 

 Orihoceras. 



Atractites (very common). 

 Aulacoceras sp. (rare). 

 Oervillia sp. 

 Mod tola sp. 

 Margarita, sp. 

 Natica sp. 



RhifticJionclla conf. solitaria, Hyatt. 

 Noihsawrus sp. 



" The bones referred to Nothosaurus* consist of a portion of 

 the backbone about thirteen inches in length, together with 

 several ribs, and fragments of other bones. Most of the species 



* Shasiasaurus pacifieus Merriam. 



