284 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Feet Meters 



At 255 feet {"jj.'j m.) from the top a strongly 



marked fauna occurs in a number of layers (66n) : 



Syntrophia isis Walcott 



Syntrophia nanus Walcott 



Syntrophia perilla Walcott 



Ozarkispira leo Walcott 



Ozomla lucan Walcott 



Keytella eupator Walcott 



Apatokephalus sp. 



Hystricurus sp. 

 In addition there are numerous gastropods and 

 several cephalopods. 

 lb. Limestones similar to those of la, but in thinner layers 

 and interbedded with thicker bands of shale, the shale 

 predominating 355 108.2 



Total Mons formation exposed 675 205.7 



Fauna. — At 95 feet (28.9 m.) from the base of ifc a 

 small fauna occurs (66p) : 



Cystid fragment 

 Protorthis porcia Walcott 

 Symphysurina ? sp. 

 Hystricurus sp. 

 The fauna 30 feet (9.1 m.) above the base of ib 

 includes (66r) : 



Straparollus sp. 

 Kainella billingsi (Walcott) 

 In a gray limestone layer arbitrarily taken as a base 

 of lb the fauna still partakes of the character of the 

 upper zone of the Mons formation (66q) : 

 Obolus sp. 

 Eoorthis sp. 

 Syntrophia isis Walcott 

 Syntrophia nanus Walcott 

 Kainella sp. 



Leiostegium keytei Ulrich MSS 

 Leiastegium truncatum Ulrich MSS 

 The section below \b is more or less covered by 

 glacial and wash deposits in the bottom of the broad 

 canyon valley between Fossil Mountain and Oyster 

 Mountain on the eastern side of the canyon. In the 

 central portion, on the low divide between Red Deer 

 River and Baker Creek, and in the northern 2 miles 

 (3.2 km.) of the canyon, the lower half of the Mons 

 is almost entirely concealed. In the southern part, op- 

 posite and east of Brachiopod Mountain, above where 

 Baker Creek enters its narrow steep canyon, iso- 

 lated outcrops of thin-bedded, dark bluish-gray lime- 

 stone, interbedded in calcareous shales of the char- 

 acteristic lower Mons, are of frequent occurrence. 



