182 EDWARD STEIDTMANN 
are exposed in contact with the older rocks. Different views as to 
the upper limits of the Belt series have been held. Daly believed 
that they were conformable with the Cambrian. Schofield reports 
that he has found an unconformity at the base of the Middle 
Cambrian and places the top of the Beltian much higher than Daly. 
Allan’ states that between Banff and Golden in the valley of 
Bow River along the Canadian Pacific Railway the pre-Cambrian 
section is as follows: Base not exposed. Corral Creek formation, 
1,320 feet composed of quartzites and coarse-grained sandstones 
with interbedded shales. Hector formation, 4,590 feet, gray, 
green, purple, siliceous shale with interbedded conglomerates. 
Remains of brachiopod-like shells in certain beds. Disconform- 
able contact with Cambrian above. 
The rocks? along the international boundary between the Por- 
cupine and Yukon rivers, classified provisionally as pre-Cambrian, 
lie on the north side of the Yukon and are peripheral to a larger 
area of these rocks south of the river. They comprise amphibolites, 
quartzite schists, mica schists, and occasional limestone beds. 
According to Daly,3 the succession of the Rocky Mountains 
along the forty-ninth parallel from the Clark range on the western 
margin of the Great Plains to the Selkirk on the one hundred and 
seventeenth meridian include the pre-Beltian Priest River terrane; 
the Beltian; Lower, Middle, and Upper Cambrian; and on the 
western border of the area, later conformable Paleozoic rocks. 
The only regional unconformity lies between the Beltian and pre- 
Beltian. , 
The pre-Beltian Priest River terrane consists of an undeter- 
mined thickness of dynamically metamorphosed sediments, notably 
mica schists, phyllites, quartzites, chlorites, schists, and dolomites 
whose stratigraphic order is unknown. The thickness exposed 
may be about 18,000 feet. They outcrop along the eastern base 
tJohn E. Allan, International Geog. Congress, Twelfth Guide Book (1913), 
pp. 167-201, maps 2, prints. 
2 DeLorme D. Cairnes, ‘‘The Yukon-Alaska International Boundary between 
Porcupine and Yukon Rivers,’ Canada Geol. Surv. Mem. No. 67 (t914), 161 pp., 
2 maps (in pocket), 2 figs., 16 pls. 
3R. E. Daly, Geology of the North American Cordillera at the Forty-ninth Parallel 
(1912), 3 parts, 840 pp., 73 pls., 42 tables, 17 geologic maps. 
