178 DEPARTMENT OF TEE INTERIOR 



2 GEORGE V.„ A. 1912 



line. The Bow River grit and conglomerate, where examined, have features 

 identical with those of the Wolf formation in the extreme western, Summit 

 series at the Boundary. The Bow River quartzite, where examined, has features 

 like both the Ripple quartzite of the Selkirks and the equivalent Wigwam sand- 

 stone of the Galton range. 



The systematic position of the Sheppard and Kintla formations, as of 

 their respective equivalents, the Gateway, Phillips and Roosville formations 

 of the Galton series, the Moyie formation of the Purcell series, and the Lone 

 Star formation of the Summit series, is not apparent from their lithological 

 comparison with the rocks of McConnell's section. 



All of these Forty-ninth Parallel formations are unfossiliferous and their 

 conditions of deposition (chiefly subaerial or in shallow water) were markedly 

 different from those under which the upper beds of the Castle Mountain series 

 (dolomitic limestones) were laid down. 



A further clue to the correlation has been found in the fact that, in the 

 Belt mountains and to the westward, the equivalent of the Siyeh formation 

 (Marsh-Helena beds) is, over large areas, conformably overlain by the fossil- 

 iferous, Middle Cambrian Flathead sandstone. This sandstone is often coarse, 

 little metamorphosed, and clearly shows its origin as a sandy deposit on the- 

 floor of a transgressing sea.§ This genetic feature seems to be well matched 

 in the character of the massive, coarse sandstone beds occurring at the base of 

 the Gateway formation, immediately above the (Purcell) lava-cap of the Siyeh.. 

 The lithological resemblance, coupled with the similar stratigraphic relations 

 to the common (Siyeh, Marsh-Helena) horizon, suggests that the lower beds of 

 the Lone Star, Moyie, Gateway, and Sheppard formations are, respectively,, 

 equivalents of the Flathead sandstone and are thus of Middle Cambrian age. 



Since the Flathead horizon is well below the recognized top of the Middle 

 Cambrian, since the succeeding Middle Cambrian time was long enough for the 

 deposition of at least 1,500 feet of limestone in the area of the Canadian 

 Pacific section, and since there is perfect conformity in all four of the Forty- 

 ninth Parallel series above the Siyeh or its equivalent, it seems probable that 

 the argillites and dolomites overlying the Siyeh or its equivalent are all or 

 nearly all of Middle Cambrian age. 



The foregoing tentative correlations are expressed in Cols. 1, 2, 7, 8, 10 

 and 12 of Table VIII. 



§C. D. Walcott, Bull Geol. Soc, America, Vol. 10, 1899, p. 209. 



