NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 2O9 



Mount Wilson, 24 feet (7.3 m.) maximum thickness and thinning out 

 on the strike to zero. Ten miles (16. i km.) north of Mount Wilson 

 it has a thickness of 100 feet (30.5 m. ) and 2 miles (3.2 km.) 

 farther north it is represented hy but a thin band of quartzite. 



Fauna. — None known. 



Geographic distribution. — From Mount Wilson on the north (C on 

 map) to the head of Clearwater Canyon (E on map), 32 miles 

 (51.5 km.) to the southeast. It extends up the north fork of the 

 Saskatchewan River 10 miles (16.1 km.) to opposite the mouth 

 of Alexandra River, where it is 100 feet (30.5 m.) thick, but 2 miles 

 (3.2 km.) farther north it has thinned down to a few feet. 



Stratigraphic Relations. — At all the outcrops seen, the quartzite was 

 subjacent to the Middle Devonian Messines limestone and overlies the 

 Canadian Sarbach limestone. 



Observations. — The Mount Wilson quartzite is one of the forma- 

 tions occurring in the Ghost River Interval (see p. 198) of which 

 we have no faunal data to determine its age. It is presumably a 

 deposit of the transgressing Devonian sea, and if this is correct there 

 were no other deposits between the time of the close of the deposition 

 of the Canadian Sarbach limestones and the incoming of the De- 

 vonian sea. No indications of erosion were observed at the summit of 

 the quartzite, or of the Sarbach limestones in the absence of the 

 quartzite. The Devonian rests on both, without evidence of uncon- 

 formity, just as it does on the Ghost River formation at Ghost River 

 (p. 210), although a great unconformity exists, as evidenced by the 

 absence of several formations occurring elsewhere. We have similar 

 conditions in connection with the Wonah quartzite, which occurs 

 50 miles (80.5 km.) to the south' in the Sinclair Canyon section. 

 Here a quartzite of similar character to the Mount Wilson quartzite 

 is subjacent to a limestone carrying a well-marked Richmond fauna, 

 proving that a basal quartzite and superjacent Silurian formations 

 were deposited in the Sinclair Canyon area of the Beaverfoot Trough 

 between the Canadian Glenogle shales and the Middle Devonian. The 

 Wonah quartzite and superjacent Silurian formations are unknown 

 in the Goodsir, Bow, Sawback, and Glacier Lake Troughs, which 

 indicates that the transgression of the Richmond sea with deposition 

 of sediments did not extend over these areas. Both quartzites are 

 superjacent to Canadian formations ; the Wonah is above the Glenogle 

 graptolite shales and the Mount Wilson above the Sarbach limestones, 

 but the Wonah quartzite is overlain by a Silurian limestone and the 



* Smithsonian Misc. Coll., Vol. 75, No. i. 1924, pp. 14, 49. 



