250 smithsonian miscellaneous collections vol. 75 



Tatei Formation. Walcott, 1913' 



Type locality. — Tatei Ridge northeast of Titkana Peak, Robson 

 Peak District. 



Derivation. — From Tatei ^ Ridge. 



Character. — Thick-bedded, siliceous and arenaceous, gray, cliff- 

 forming limestones. 



Thickness. — 800 feet (243.8 m.). 



Fauna. — Unknown. 



Observations. — The Tatei, on account of its hard, thick-bedded 

 limestones, resists erosion to a greater extent than the limestones of 

 the Titkana and subjacent Chetang, and despite long-continued glacia- 

 tion forms a marked cliff on the ridge northeast of Titkana Peak. It 

 is probably a relatively local deposit and may not be recognized outside 

 of the Robson District. 



Ptarmigan Formation. Walcott, 1917" 



Type locality. — -South base of Ptarmigan Peak, 4.75 miles (/.y km.) 

 northeast of Lake Louise Station on the Canadian Pacific Railway. 



Derivation of name. — From Ptarmigan Peak. 



Character. — More or less arenaceous gray limestone, with inter- 

 bedded bands of thinner-bedded, dark bluish-black limestones and 

 some interbedded beds of shale. 



Thickness. — At Ptarmigan Peak, 516 feet (157.3 m.) ; at Bow 

 Lake 20 miles (32.2 km.) northwest of Ptarmigan Peak, 534 feet 

 (162.8 m.) ; at Ross Lake, 8.5 miles (13.7 km.) west-southwest of 

 Ptarmigan Peak, 664 feet (202.4 m-) ! ^t Castle Mountain in Bow 

 Valley, 272 feet (82.9 m.) ; at Ghost River on Rocky Mountain 

 front, 1,122 feet (341.9 m.). 



Geographic distribittion. — Ptarmigan Peak, Mount Bosworth, 

 Mount Pope, Rocky Mountain front between Devils Gap and Ghost 

 River, and presumably far to the north up the Bow Valley and to 

 the north of the Saskatchewan River. Its characteristic Alhertella 

 fauna occurs in the Robson District section above Coleman Brook, and 

 far to the south of the Bow Valley near the North Kootenay Pass. 



Fauna. — A large and varied lower Middle Cambrian fauna, that 

 was described and illustrated in 1917,'' occurs in the section at Ross 

 Lake. 



* Smithsonian Misc. Coll., Vol. 57, No. 12, p. 334. 



" Name first spelled Tatay, but was afterward changed to Tatei by Geographic 

 Board of Canada. 

 ' Smithsonian Misc. Coll., Vol. 67, No. i, 1917, pp. 1-4. 



* Idem, No. 2. 



