608 THE JOURNAL OF GEOLOGY. 



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 Atvactites 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. 



Tropites subbullatus, Hauer. 



'• sp. (with narower coil). 



" sp. (with high ribbed whorl). 



" saturnus, Dittmar. 

 Halorites conf. ramsaneri, Gabb. 

 Eutomoceras sandlengense, Hauer. 

 Etitomoceras, sp. 

 Acrochordiceras sp. 

 Lee unites sp. 

 Arcestes sp. 



Nautilus triadicus, Mojsisovics. 

 Orthoceras ? 



Atraetites (very common). 

 Aulacoceras sp. (rare). 

 Gervillia sp. 

 Modiola sp. 

 Margarita sp. 

 Natica sp. 



Rhynchonella conf. solitaria, Hyatt. 

 Nothosaurus 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 were 

 found in much greater numbers and better preservation in the 

 underlying Trachyceras beds, so that there is no great faunal dis- 

 tinction between the two horizons. 



The Spiriferina beds. — These beds are made up of about 50 



