248 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



in the Saskatchewan Valley by the Murchison formation, and 125 

 miles (201. 1 km.) to the north, in the Robson Peak section, by the 

 Titkana formation. 



Fauna. — The large and abundant fauna is of Middle Cambrian 

 age. Some of the genera and species are listed in the section. 



Murchison Formation. Walcott, 1919, 1923^ 



Type locality. — Cliffs south and above Siffleur River, about 12 miles 

 (19.3 km.) east-northeast of Mount Murchison. 



Derivation of name. — From Mount Murchison. 



Character. — Bluish-black compact limestones above and below, 120 

 feet (36.6 m.) of dove-colored and gray limestones. 



Thickness. — 497 feet (151. 5 m.) in the Siffleur section. 



Geographic distribution. — Known only about the headwaters of the 

 Saskatchewan River at Glacier Lake, Mount Murchison, and above 

 the Siffleur River in the northeastern spurs of Mount Sedgwick. 

 The Murchison may prove to be the same formation as the Stephen of 

 Mount Stephen above Field, British Columbia, but in the absence 

 of the Eldon above it, a close correlation cannot be made. 



Stratigraphic relations. — A massive-bedded, dolomitic limestone 

 occurs beneath the Murchison that is of the same type as the Cathedral 

 limestone of the Mount Bosworth and Mount Stephen sections of 

 the upper Kicking Horse Canyon area, but the upper limit is defined 

 by the presence of thin, parti-colored layers of dolomitic limestones 

 of the Arctomys formation. 



Fauna. — The Murchison formation appears to contain a typical 

 Stephen fauna. 



Titkana Formation. Walcott, 1913'' 



Type locality. — Titkana Peak, Robson Peak District. 



Derivation. — From Titkana Peak. 



Character. — Massive-bedded, bluish gray limestones composed of 

 thin lavers that break down on weathered slopes. Bands of hard, gray, 

 siliceous and dolomitic buff-weathering limestones, 50 to 100 feet 

 (15.2 to 30.5 m.), are interbedded at irregular intervals. 



Thickness. — As hastily measured and estimated, 2,200 feet 

 (670.6 m.). 



Geographic distribution. — As far as known, the Titkana occurs 

 only in the Robson Peak District. It may be compared with the 



' Smithsonian Misc. Coll., Vol. 67, No. 8, p. 462. 

 ^ Idem, Vol. 57, No. 12, p. 334. 



