GEOLOGIC FORMATIONS 747 



drawing' of a line between them and the Miette sandstones is described 

 as a matter of some difficulty (§9). 



(§ 335.) The qnartzitic limestones which underlie the Mural lime- 

 stone formation in the Mount Eobson region may or may not be directly 

 underlain by the pre-Cambrian, and may or may not be correlateable 

 with the McNaughton sandstones. Even though they form, so far as 

 known, the exposed base of the Cambrian sequence in the Mount Eobson 

 region, we prefer to leave their naming to the future student who shall 

 determine their relations to the pre-Cambrian. 



MIETTE SANDSTONES (§34) 



The Miette sandstones are described by Walcott as having an esti- 

 mated thickness of 2,000 feet, and as being best exposed along both sides 

 of Yellowhead Pass from Grant Brook on the west to Fitzhugh on the 

 east, and to be overlain by the McNaughton sandstones, the line of 

 demarcation being very uncertain. The writer did not find the contact 

 between the Cambrian and the pre-Cambrian in the Mount Robson region 

 and is unable to add to the description given (§9). 



