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MIDDLE CAMBRIAN. 



Cathedral Formation. — This formation consists of 

 massive and thin bedded dolomitic limestone, which on 

 the weathered surface becomes buff and gray. The more 

 massive beds are arenaceous in their composition. It 

 is on this formation that the Monarch mine in Mt. Stephen 

 is situated, and other small mineral prospects in the 

 Kicking Horse valley. 



Castle Mountain, showing Cathedral limestone in the lower cliffs; Stephen formation 



in the talus covered slope; and the Eldon formation in the upper cliffs. 



(All Middle Cambrian). 



Some of the limestone has become metamorphosed into 

 marble. One of the best exposures of this rock is in 

 Cathedral mountain, four miles (6-4 km.) east of Field. 



Stephen Formation. — Although this formation is 

 only 640 feet (196 m.) thick, yet it is quite important for 

 the number and variety of fossils which it contains. It 

 consists of shaly limestone and calcareous shale. These 

 beds include the 'Ogygopsis shale' in Mt. Stephen, and 

 the 'Burgess shale' in Mt. Field, on the opposite side of 

 the valley. The former includes the widely known trilo- 

 bite-bearing 'fossil bed,' while the latter includes the 

 new 'fossil bed,' discovered by Walcott in 1910. From 

 this bed he has obtained an extensive variety of Middle 

 Cambrian organisms. Coelenterata, Annulata, Echinoder- 



