175 



5 to 15 mm. in diameter. Some of the quartz grains have 

 a glassy, almost opalescent colour. 



Lake Louise Formation. — As the name indicates, 

 these beds are best exposed at Lake Louise. The formation 

 has a total thickness of 105 feet (32 m.) and consists of a 

 ferruginous siliceous shale. It weathers more readily 

 than the beds below or above, so that the slopes are more 

 gradual. 



Mt. Temple, showing a complete Lower and Middle Cambrian section capped by Upper 

 Cambrian, and underlain by Pre-Cambrian shales (covered by talus). 



St. Piran Formation. — This formation consists of 

 massive-bedded, ferruginous, quartzitic sandstone, with a 

 total measured thickness of 2,705 feet (824 m.). These 

 beds form steep escarpments wherever they are exposed. 

 On the west side of Mt. Victoria the cliffs composed of 

 these beds are over 2,500 feet high. The brown color 

 of the rock is due to smoky quartz and small particles of 

 mica in the cement. 



Mt. Whyte Formation. — In sharp contrast with the 

 underlying massive quartzites, there is a thin series of 

 siliceous and calcareous shales grouped as the Mt. Whyte 

 formation. These shales are less resistant than the quart- 

 zite and form gradual slopes. Some of the layers contain 

 numerous annelid borings and trails. 



