NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 325 



the Ptarmigan bluish-gray Hmestones is clearly defined. Both lime- 

 stones strike about north 40° west, and dip 15° to 20° to the south- 

 west. 



MIDDLE CAMBRIAN 



Cathedral Formation p^^^ Meters 



Massive-bedded, coarse, gray, rough-weathering limestone. 



Ptarmigan Formation 



1. Bluish-gray, thin layers in massive beds 108 32.9 



Fauna. — Neolenus (fragments) . 



2. Ross Lake shale. Dark siliceous shale, with Albertella 



fauna 6 i .8 



Fauna. — (63W) : 



Acrothclc colleni Walcott 

 Wimanella simplex Walcott 

 Vanu.vemella nortia Walcott 

 Agraulos stator Walcott 

 Albertella sp. 



3. Thin layers of bluish-gray limestone in massive beds, 



breaking down on slopes. It quickly becomes more 

 massive-bedded and cliff-forming, and passes below 

 into a gray coarse rock 154 46.9 



4. Deep, bluish-gray, massive-bedded, coarse limestone, 



more or less mottled on weathered surface. In bands 



that break up into thin beds 144 43.9 



5. Light gray more or less mottled, rough-weathering lime- 



stone in massive layers, 6 to So feet (1.8 to 15.2 m.) 



thick. Annelid borings 122 37.2 



Total Ptarmigan formation 534 162.7 



LOWER CAMBRIAN 

 Mount Whyte Formation 



1. Thin-bedded, rough surfaced, bluish-gray limestone, 



passing into coarser magnesian, buff -weathering, thin- 

 bedded limestone 60 18.3 



2. Massive bed of gray limestone, with stringers and no- 



dules of magnesian limestone 12 3.7 



3. Coarse, siliceo-argillaceous shale, dirty-gray in color... 5 1.6 



4. Bluish-gray limestones in beds varying 2 inches 



(5.1 cm.) to 2 feet (.6 m.) in thickness. Some beds 

 oolitic near the summit, and carrying Nisusia, Hyo- 

 lithes, and fragments of large and small trilobites. ... 32 9.8 



5. Rough, arenaceous shale with annelid trails. Gray- 



weathering, dirty, buff-brown. Thin layers of bluish- 

 gray limestone interbedded in lower portion 36 10.9 



6. Light gray limestone, with stringers and splotches of 



buff-weathering magnesian limestone 6 1.8 



