254 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



Derivation. — From Lake Louise, Alberta. 



Character. — Compact, gray siliceous shale. 



Thickness. — At Lake Louise on the northeast side of the Beehive, 

 105 feet (32 m.). 



Geographic distribution. — This shale is limited as far as known to 

 the vicinity of Lake Louise and along the front of the Bow Range 

 to Vermilion Pass. 



Fauna. — Annelid and trilobite trails, a small brachiopod, Micro- 

 metra (IpJiideJla) Ionise Walcott, a Hyolithes, and a fragment of a 

 trilobite. 



Observations. — The Lake Louise shale is a good horizon marker 

 and locally serves to separate the St. Piran and Fort Mountain 

 formations. It may extend across Bow River Valley into Mount 

 Bosworth, but it was not seen there or at Redoubt Mountain. 



Fort Mountain Formation. Walcott, 1912' 



Type locality. — Redoubt Mountain, about 5 miles (8 km.) north 

 of Lake Louise Station on the Canadian Pacific Railway. 



Derivation. — From Redoubt ^ Mountain. 



Character. — Massive-bedded, cliff-forming, purplish, hard, fine- 

 grained quartzitic sandstones, with bands of siliceous and finely are- 

 naceous shale in lower portion. An arenaceous, quartzitic basal con- 

 glomerate occurs in some localities. 



Thickness. — At Redoubt Mountain the formation is finely exposed, 

 but it was not measured in detail. The basal conglomerate is 360 

 feet (109.7 "!•) i" thickness with a band of shale 44 feet (13.4 m.) 

 thick above it, and superjacent to the shale, several hundred feet of 

 quartzitic sandstones. At Fairview Mountain (see p. 302), 940 feet 

 (286.5 ^'^■) ^^ thickness is exposed, and on the north slope of Mount 

 Temple, the lower sandstone outcrops down to its contact with the 

 pre-Cambrian. In its greatest development the formation has a thick- 

 ness of 1,324 feet (403.5 m.) on the south side of the Bow River 

 Valley. 



Geographic distribntio7i. — The formation is known from Mount 

 Stephen eastward to Kicking Horse Pass and southeast down the Bow 

 River Valley to Castle and Copper Mountains. "It forms a great 



* Monogr. U. S. Geol. Surv., 51, p. 131. 



' The name Fort Mountain occurs on a topographic map of the Rocky Moun- 

 tains, Department of the Interior, Canada, 1903- 1907, Arthur O. Wheeler, 

 Topographer. On a map issued in 1914 of the Selkirk and Rocky Mountains, 

 Department of the Interior, it is changed to Redoubt Mountain, and this is 

 continued on subsequent maps, having been approved by the Geographic Board. 



