176 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



of the Summit series was marked, and even more striking was the likeness of 

 the reddish beds to standard phases of the Wigwam formation of the Galton 

 series and the Grinnell formation of the Lewis series. No fossils were dis- 

 covered in the quartzite. 



The Bow Biver conglomerate and grit were also best seen in the Laggan 

 section. Only 1,200 feet of these rocks appear, the base being here hidden 

 beneath the Glacial gravels of the Bow valley. All stages of transition are 

 represented between the conglomerate with well-rounded pebbles an inch or 

 less in diameter, to a quartzitic sandstone of medium grain. The abundant 

 and heavy beds of grit represent the rock of intermediate grain. These three 

 sedimentary types occur in alternation through the whole 1,200 feet, though 

 the conglomerate lenses seem most common toward the top. All the strata 

 belong to one great lithological individual of heterogeneous grain but rather 

 constant chemical composition. The conglomerate is made up of glassy, white, 

 or bluish, often opalescent quartz pebbles with subordinate, large rounded 

 grains of feldspar. These fragments are all cemented in a silicious matrix, 

 itself feldspathic to some extent. The grits and sandstones are but finer grained 

 phases of the same silicious, sedimentary material. In composition and the 

 gray and greenish colours of fresh and weathered surfaces, the conglomerate 

 and grit can hardly be distinguished from staple phases of the Wolf grit of 

 the southern Selkirks. The similarity even extends to such a detail as the 

 changeable tints of the opalescent quartz pebbles and grains. No fossils were 

 found in this division of the Bow Biver formation, though it was apparently 

 within this subdivision that Dawson found Lower Cambrian fossils at Ver- 

 milion Bass. 



It would be highly desirable to have studied in the field the Bow Biver 

 beds below the conglomerate-grit member and also the upper part of the Castle 

 Mountain formation, but sufficient time for this could not be spared out of the 

 field season. Yet it is believed — and Mr. McConnell, to whom the field data and 

 typical specimens were submitted, agrees in the belief — that sufficient evidence 

 has already been secured to suggest the stratigraphic relation of the Castle 

 Mountain-Bow Biver group to the old sedimentary prism traversed at the 

 Forty-ninth Farallel. 



The suggested correlation is as follows. The lower 4,000 feet or more of the 

 Castle Mountain limestone is stratigraphically equivalent to the Siyeh formation 

 and thus to the larger part of the Kitchener quartzite, and, again, to the larger 

 part of the Beehive quartzite. The 1,500-foot quartzite immediately under- 

 lying the Castle Mountain limestone is the equivalent of the Grinnell and 

 Wigwam formations, of the lowest beds of the Kitchener quartzite, and of the 

 Ripple quartzite. The Bow Eiver conglomerate-grit member at the base of the 

 Laggan section is equivalent to the Dewdney quartzite and upper part of the 

 Wolf grit formation in the southern Selkirks. 



Since the foregoing paragraphs were written, Walcott has made a detailed 

 study of the Castle Mountain group. His results corroborate McConnell's 

 stratigraphy and show yet more precisely the range of the Upper, Middle, and 



