340 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Feet Meters 



Fauna.^ — The following species were collected from masses 

 of rock brought down by Mons glacier. 

 Stromatopora sp. 

 Cyathophyllum sp. 

 Atrypa reticularis (Linn.) 

 DiSCONFORMITY 



CANADIAN 

 Sarbach Formation 



1. Thick-bedded, gray limestone breaking up into layers of 



varying thickness (i to 16 inches, 2.5 to 40.6 cm.). 

 Thickness estimated because of inaccessible cliffs... 700 213.3 



Fauna. — 



Or this 2 sp. 



Illaenus ? sp. 



2. Drab-colored, argillaceous shales weathering buff and 



yellow, and breaking down readily on weathering.... 420 128.0 



Fauna. — Fragmentary fossils occur in interbedded layers 

 of limestone most of which are very hard and semi- 

 crystalline, and often crowded with small concretions 

 and irregular flattened nodules of limestone, with 

 some cherty stringers and nodules. 



Dr. E. O. Ulrich considered that the fossils indi- 

 cated that the faunule was of Canadian (Beekman- 

 town) age. 



From a compact gray limestone beneath Devonian 

 limestones on the east side of the canyon leading up to 

 Wilcox Pass, 23 miles (37 km.) north of Glacier Lake 

 and about 3 miles (4.8 km.) south of the Pass, the 

 following faunule, referred to the Sarbach fauna, 

 was collected (67h) : 



Protorthis cf. porcias Walcott 

 Isoteloides sp. 



Total of Sarbach formation 1,120 341-3 



There is no apparent unconformity between the base 

 of the Sarbach and the subjacent Mons shales. 



OZARKIAN 

 Mons Formation 



\a. Massive strata formed of calcareous shale, with thin, 

 compact, irregular layers of bluish-gray, hard lime- 

 stone; layers of hard, semi-crystalline limestone 2 to 

 12 inches (5 to 30.5 cm.) thick are interbedded at ir- 

 regular intervals. The series is very much like that 

 below ic in this section 235 71.6 



^ Middle Devonian, equivalent to the Jefferson limestone. — Kirk. 



