NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 309 



sections in the Canadian Rockies. North of Mount Bosworth, the 

 sequence and character of the formations, as expressed throughout 

 the Bow Range, begin to change, and the section loses its completeness. 



UPPER CAMBRIAN 

 Sherbrook Formation p^^^ ^^^^^^ 



I. Massive-bedded, bluish-gray limestone, with some cherty 

 matter in the form of small nodules and stringers ; 

 also irregular partings and fillings of annelid borings 



by gray dolomitic limestone weathering buff 175 53.3 



Fauna : Annelid borings and trails. Fragments of unde- 

 termined trilobites. 

 2a. Gray oolitic limestone in thick layers, with bluish banded 

 limestone intercalated at irregular intervals. The 

 banded appearance of the non-oolitic layers is due 

 to the buff weathering of the thin dolomitic layers. . . . 190 57.9 



Fauna. — (57z) : 



Crepiccphalus ? sp". 

 Two new genera of trilobites 

 2b. Greenish-drab and gray siliceous shales, with inter- 

 bedded oolitic limestone in bands of layers from 

 6 inches (15.2 cm.) to 4 feet (1.2 m.) thick; also a 

 few bands of thick-bedded, bluish gray limestone that 



breaks up into shaly limestone on weathering 335 102.1 



Fauna. — (57d) : in green shales near summit 



Lingulella cf. isse (Walcott) (1905, p. 330) 

 Fauna. — (58f) : in oolitic layers. 



Agrwstus, sp. undt. 

 Kingstonia sp. 

 This species was also found in a loose block of oolitic 

 limestone on the slope just beneath the outcrop of 2b 

 (580). 

 2c. Gray oolitic limestone, with thin bands of interbedded 

 shaly, blue-gray limestone. Gray, dolomitic, buff- 

 weathering, flattened nodules, stringers, and thin layers 



of limestone occur in a very irregular manner 65 19.8 



Fauna. — (57p) : 



Agnostus sp. 

 Kingstonia sp. 



Total of 2 590 179.8 



3. Arenaceous, dolomitic, steel-gray limestone weathering 



light gray and buff-gray 610 185.9 



The line of demarcation between 3 and the bluish- 

 gray limestones below is irregular. The gray beds of 

 3 extend along the cliff and abruptly change to bluish- 

 gray. In the upper 100 feet (30.5 m.) of 3, irregular 



