NO. 5 PRE-DEVONIAN PALEOZOIC FORMATIONS 221 



magnesian limestones. At the head of Douglas Creek, 7 miles (11. 3 

 km.) east of Fossil Mountain, it has a thickness of 520 feet (158.5 m.) 

 of cherty magnesian limestones similar to those in Ranger Canyon. 



In character and thickness the Sarbach is quite uniform from 

 Glacier Lake to Fossil Mountain, a distance of over 50 miles 

 (80.5 km). 



Geographic distribution. — The Sarbach has not been noted north 

 of the Saskatchewan drainage area (B, C, D on map) or south of the 

 Baker Lake area (F on map) except as represented by the trilobite 

 Megalaspis, in the Sinclair Canyon section (N on map) at the head 

 of Windermere Creek. It appears to have a north and south range of 

 about 80 miles (128.7 k^-) and to occur in the Glacier Lake, Saw- 

 back, and Beaverfoot Troughs. The Sinclair Canyon occurrence in- 

 dicates that the formation may be looked for in the interval between 

 Sinclair Canyon and Glacier Lake. 



Stratigraphic relations. — The Sarbach ' at its typical locality on 

 Mount Sarbach is beneath the dark Middle Devonian limestones 

 without apparent unconformity between them, but at Mount Wilson, 

 8 miles (12.8 km.) north, a white quartzite over 250 feet (76.2 m.) 

 thick made up of massive layers forms a cliff beneath the Devonian 

 and above the Sarbach (see pi. 79). In the Clearwater Canyon sec- 

 tion (E on map) 33 miles (53.1 km.) to the east-southeast, the same 

 conditions occur except that the quartzite is only 24 feet (7.3 m.^ 

 thick, and a short distance to the eastward it thins out and disappears 

 (see pi. 82), so that the Devonian rests on the Sarbach. 



On the northeast shoulder of Fossil Mountain (F on map) the 

 Ordovician Skoki formation occurs between the Devonian and the 

 Sarbach, but at Ranger Canyon (H on map) and the head of Lake 

 Douglas Creek (G on map) there is only a thin band of arenaceous 

 shale between them. 



The lower boundary of the Sarbach in the Sarbach-Glacier Lake 

 area is at the base of a strongly-defined cliff on the south side of Mons 

 glacier (pi. 91). In the Clearwater section the thick-bedded siliceous 

 and magnesian limestones of the Sarbach rest on a band of thinner 

 layers, carrying a fauna of Canadian facies, which in turn are 

 superjacent to the bluish-gray limestones that are referred to the 

 Ozarkian Mons formation. The lower boundary is also distinctly 

 exposed on the east side and northeast shoulder of Fossil Mountain, 

 near Baker Lake (F on map). 



^Smithsonian Misc. Coll., Vol. 72, No. i, 1920, p. 15; Vol. 67, No. 8, 1923, 

 P- 459- 



