224 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



tional conglomerate made up of small fragments of shaly limestone 

 in a calcareous matrix. The sea was shallow in early Ozarkian time 

 and a different fauna came in after the change in conditions following 

 the close of the Cambrian. 



Southern CordiUcran area. — In the Blacksmith Fork section and 

 other places on the western front of the Rocky Mountains, well-defined 

 Ozarkian beds of Mons age are known but in no case has a definite 

 boundary been drawn, because all the collections in hand were made 

 before the significance of the faunas was grasped. 



No definite decision can yet be made regarding the position of this 

 boundary in the Eureka District. Nevada. Whether to draw it at the 

 top of the Secret Canyon shale or include the overlying Hamburg 

 limestone in the Cambrian cannot be decided until the stratigraphic 

 meaning of the Hamburg fossils has been learned. It is certain that 

 the lower portion of the Pogonip formation, now designated as the 

 Goodwin formation, is to be correlated with the Mons. No good 

 contact of the Goodwin on the underlying beds has yet been found, 

 and the problem is further complicated by the mistaken conception 

 of the main Eureka District section as a simple anticlinal structure 

 when in reality it consists of a repetition of the formations by thrust 

 faulting. 



In the House Range of Utah, the Notch Peak formation was 

 tentatively referred to the Ozarkian owing to the inexact information 

 as to the stratigraphic meaning of its fauna. Now however it has 

 been proved that the underlying Orr formation is to be tentatively 

 correlated with the lower Upper Cambrian Eau Claire formation 

 of Wisconsin and that the Notch Peak belongs closely above it. This 

 reassignment eliminates all Ozarkian from the House Range. 



Mons Formation. Walcott. 1920^ 



Type locality. — Southeast side of Mons glacier, near base of north- 

 west ridge extending down from Mount Forbes at the head of Glacier 

 l^ke Canyon Valley, about 48 miles (77.2 km.) northwest of Lake 

 Louise Station on the Canadian Pacific Railway, Alberta. 



Derivation. — From Mons Peak, 10,114 feet (3,082.7 m.), and Mons 

 glacier, which extends eastward from below the peak. (See pi. 91.) 



Character. — An upper section of massive beds of calcareous shale 

 with thin, intercalated layers of hard, gray limestone. A middle section 

 of thick-bedded, dull gray limestone with a little included arenaceous 



^ Smithsonian Misc. Coll., Vol. 72, No. i, 1920, p. 15 ; also Vol. 67, No. 8, 

 1923, P- 459- 



