CORRELATION OF SECTIONS 25 



ern edge of "Tobacco plains. Of this section he said in a preliminary 

 report :* 



"These sediments include an extraordinary thickness of conformable 

 quartzite and argillites, the former dominating. The whole group has, on 

 lithologic and stratigraphic grounds, been divided into four series. The lowest 

 series, the Creston quartzite, is composed of 9,500 feet of wonderfully homo- 

 geneous, highly indurated, thick-platy gray sandstones. Overlying the Creston 

 quartzite is the Kitchener quartzite, a second series of ancient, hard sandstones 

 and interbedded argillites, carrying a high proportion of disseminated iron 

 oxides. These rusty rocks are, relatively, thin bedded and bear very abundant 

 sun cracks and ripple marks on horizons ranging from top to bottom of the 

 series. The thickness of the Kitchener quartzite is about 7,400 feet. It is 

 itself conformably overlain by at least 3,200 feet of thin bedded, red and gray 

 argillaceous strata which, together with subordinate thin beds of light gray 

 quartzites, make up the formation I have called the Moyie argillite. The 

 youngest member of the four sedimentary divisions is the Yahk quartzite, com- 

 posed of white to gray indurated sandstones bedded in thin to medium courses. 

 The top of this series was not seen ; the whole thickness observed is 500 feet. 

 The total observed thickness of conformable strata is nearly twenty thousand 

 feet. Neither the bottom of the Creston quartzite nor the top of the Yahk 

 quartzite appearing in the sections, it is certain that this great thickness is 

 only a minimum thickness." 



"The westward extension of this sedimentary series was mapped and 

 measured during 1903 in the boundary belt immediately west of the Kootenay 

 at Port Hill. There the strata corresponding to the Creston quartzite are 

 conglomerates, grits and coarse sandstones as well as fine grained sandstones, 

 and are thus, on the whole, notably coarser than they were found to be any- 

 where in this season's belt. The equivalent of the Kitchener quartzite is less 

 strongly charged with argillaceous beds than is the Kitchener quartzite east 

 of the Kootenay. These facts point to the conclusion that the shoreline, 

 whence the materials composing the stratified formations were derived, lay 

 to the westward and that the open sea and deeper water lay to the eastward 

 of the western crossing of the Kootenay river at the International boundary. 



"This conclusion was strikingly confirmed on carrying the section towards 

 Gateway. It was found that both the Creston quartzite and the Kitchener 

 quartzite gradually became charged with interleaved beds of calcareous 

 quartzite, calcareous argillite and siliceous limestone, betokening open-water 

 conditions during the formation of these sediments. In fact, the transition of 

 the great quartzite series to certain of the more calcareous formations of the 

 Rocky mountains has become the best working clue to the correlation of the 

 rocks of the Purcell range with those of the Rocky Mountain front. If this 

 conclusion be confirmed by the further eastward extension of the boundary 

 section next year, it will mean that the Creston and Kitchener quartzites and, 

 possibly, also the Moyie argillite and Yahk quartzites are of pre-Cambrian 

 age. The nearest relatives of the Creston and Kitchener quartzites in the 

 Rockies are respectively the two thick members of the Altyn limestone de- 



* Summary Report Geological Survey of Canada for 1904, issued 1905, p. 96. 

 IV— Bull. Geol. Soc. Am., Vol. 17. 1905 



