336 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Feet Meters 



ir. Shaly and slab by, hard, compact, gray, buff- and red- 

 dish-brown-weathering dolomitic Hmestone, with 

 purplish-colored beds from 80 to 100 feet (24.3 to 

 30.4 m.) above the base; also dark and a few greenish 

 bands of siliceous shale 28=; 86.Q 



Total thickness of Arctomys formation 725 221.0 



The Arctomys formation was a shallow water de- 

 posit where the conditions were unfavorable for the 

 existence of life, as no traces of trails or fossils were 

 seen. It represents a period of deposition in shallow 

 water — probably brackish or fresh water. The great 

 Eldon limestone, 2,728 feet (831.4 m.) thick on Mount 

 Bosworth 40 miles (64.3 km.) to the south, is not 

 present below the Arctomys, owing probably to non- 

 deposition, as no indications of a fault or of its having 

 been removed by erosion were observed. 



MIDDLE CAMBRIAN 

 MuRCHisoN Formation 



la. Thin layers of bluish-black limestone below, passing 

 gradually upward into a steel-gray fine-grained, com- 

 pact limestone with thin bands of interbedded, bluish- 

 black and gray limestone 132 40.2 



lb. Compact, hard, irregularly-bedded, dove-colored and 

 gray limestone in thin layers forming massive bands 

 15 to 20 feet (4.5 to 6 m.) thick 120 36.6 



ic. Bluish-black, hard, shaly limestone, with annelid trails 



and fragments of fossils on the surface. . . . ." 140 42.7 



Fauna. — (65q) : 



Glossopleura sp. 



id. Thin-bedded, dark, bluish-gray, more or less siliceous 

 limestone, breaking down into small angular frag- 

 ments 105 32.0 



Total thickness of Murchison formation 497 I5i-S 



The Murchison formation appears to represent the 

 Stephen formation of the Mount Bosworth-Kicking 

 Horse River section. The Eldon limestone is not pres- 

 ent above it in this area. 



Cathedral Formation 



I. Massive-bedded, dark and rough-weathering, more or 

 less dolomitic limestone with a finely granular struc- 

 ture and surface, often breaking down into thin 



layers 520 158.5 



Strike W. 20° N. Dip S. 20° W. (Magnetic). 



2a. Light gray limestone in massive layers more or less 

 laminated on cliff exposures, often breaking down into 

 low cliffs and terraces 350 106.7 



