176 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



period is represented by the Banff lime series, which, including two shaiy zones, 

 has a thickness of 5,100 feet. This has yielded a number of fossils and these 

 show that the series as a whole represents the lower part of the Carboniferous, 

 passing below into the Devono-Carboniferous. The later part of the Carbonifer- 

 ous period seems either to be unrepresented, or, if represented at all, to find but 

 a partial equivalent in the upper shales. It is thus very probable that before 

 the close of the Carboniferous the present position of the Rocky Mountains 

 formed part of a land area. 



"It has already been noted that the lower portions of the Cache Creek forma- 

 tion may be older than the Carboniferous period. The very general blending 

 of the Carboniferous and De^'onian systems in the West shows that no well- 

 marked line need be anticipated at the base of the Carboniferous. The separation 

 of any beds of Devonian age can only be made in the event of the future discovery 

 of characteristic fossils. The same may be said respecting the possible existence 

 of Silurian or Cambro-Silurian beds." 



In the Summary Report of the Canadian Geological Survey for 1915, 

 Camsell,' writing upon the Stewart, Tacla, and Trembleur Lakes area and 

 the Omeneca Placer district describes the rocks of the various regions. On 

 Stewart Lake there is a massive blue limestone which carries Fusulina. 

 This led Dawson^ to refer it to the Carboniferous. Below the limestone 

 are cherty quartzites, argillites, and greenstone schist, the latter probably 

 derived by alteration from volcanics. The beds are much disturbed and 

 dip at high angles. On Tacla Lake to the north of Stewart Lake there are 

 blue and gray sandstones and slates with small bands of dark-blue limestone. 

 In near-by localities (Germania Creek and Manson River) are volcanic 

 flows, tuffs, and breccias or chloritic schists and slates with narrow bands 

 of ferruginous dolomite. These beds are correlated with those of the 

 Stewart Lake area by lithological and structural characters only. 



(The similarity of limestone here described and its position above the 

 series of metamorphic sediments and volcanics, to the limestone on the 

 western side of the great bathylith is at least striking and suggestive.) 



In the Bridge River Map Area near Chilkas Lake, Drysdale^ has de- 

 scribed Paleozoic rocks which he calls Devono-Carboniferous and places in 

 the Cache Creek Series. He gives the following section: 



White Cap schist series 8,ooo± feet. Quartzite, mica schist, andalusite schist, 

 squeezed conglomerate and sandstone, phyllite, talcosic, sericitic, and chloritic schist. 



Bridge River series 9,500± feet. Mainly contorted chert and cherty quartzite. Red 

 arenaceous schist, metargillite, and crystalline limestone in lenses. Flows of basalt mainly 

 near the top. 



' Camsell, Charles, Exploration in the Northern Interior of British Columbia, Summary 



Report Canadian Geological Survey for 1915, p. 70, 1916. 

 ' Canadian Geological Survey, Report of Progress, 1871-77, p. 55. 

 ' Drysdale, C. W., Bridge River Map-area, Lillooet Mining Division, British Columbia, 



Summary Report Canadian Geological Survey for 1915, p. 75, 1916. 



