DEFINITION OF THE SELKIRK SERIES. 171 



The Selkirk Series. — Between tlie foregoing series and the next overlying 

 mass of beds in the Selkirk section no distinct line of division, even of a 

 lithological character, has been observed, there being apparently, on the 

 contrary, a considerable thickness of passage beds, in which the dark schists 

 of the lower series alternate with gray quartzites and gray glossy schists 

 characteristic of the upper series. The estimated thickness of this overlying 

 series is 25,000 feet ; and of its rocks the higher central peaks of this part 

 of the range, comprising mounts Sir Donald, Macdonald, Tupper, Hermit, 

 Cheops, Ross peak and others, appear to be wholly composed. Litholog- 

 ically, it consists of a great volume of gray schists and gray quartzites, which 

 are occasionally somewhat dolomitic. The quartzites probably preponderate, 

 and vary in color from nearly white to gray and greenish-gray, being seldom 

 dark in tint. They often, however, weather to pale brownish colors and pass 

 into coarse grits and fine-grained conglomerates ; and these grits and con- 

 glomerates have become more or l<?ss schistose in structure as a result of 

 pressure, which has also led to the development in them of much fine silvery 

 mica. The schists vary in color from pale neutral-gray to greenish-gray, 

 and from dull to silvery and lustrous, being in many cases apparently true 

 sericite-schists. They are sometimes wrinkled and contorted, particularly 

 on the east side of the main synclinal, where also they occasionally become 

 coarsely micaceous. To the east of this main synclinal and beyond the great 

 fault shown in the diagrammatic section (p. 174) they are more crushed 

 and altered and more highly micaceous than elsewhere, probably as a result 

 of the dynamic conditions to which they have been subjected in this region. 



The rocks of this great series appear to represent the Adams Lake series 

 to the west, while they undoubtedly correspond, at least in a general way, to 

 the Castle Mountain group of the Rocky Mountain section on the east, for 

 which group Mr. McConuell ascertained a minimum thickness of 7,700 feet, 

 but found reason to believe that its total volume in the western part of the 

 range approached 10,000 feet. 



It will be understood from what has already been said that the line indi- 

 cated between this and the underlying series in the Selkirks is based entirely 

 on general lithological differences, while there is every reason to believe 

 that a plane of division drawn to correspond with that between the Castle 

 Mountain and Bow River series in the Rocky Mountains would lie several 

 thousand feet above the recognized summit of the Nisconlith series in the 

 Selkirks. In the Rocky Mountains, the lower Cambrian {^OlenelUis) fauna 

 is known to be common to the lower part of the Castle Mountain and upper 

 part of the Bow River series;* the separation being there made at the base 

 of the distinctly calcareous upper part of the Cambrian, while certain rather 

 characteristic quartz-conglomerates observed in the upper part of the Bow 



*Tliis fauna is known to characterize several thousand feet of the Castle Mountaia series, and 

 has been found as well about 3,0u0 feet down in the upper part of the Bow River series. 



