CORRELATIVES OF THE SELKIRK FORMATIONS. 169 



plateau region and is based on observations made on Kootanie lake in the 

 western flanks of the Selkirks, supplemented by a section found on and near 

 Adams and the Sl^uswap lakes, about 150 miles to the northwest of the first- 

 mentioned locality. The lowest rocks in this column are those referred to 

 the Archeau, the thickness stated being merely that known to occur on 

 Kootanie lake. The rocks included in the Adams Lake series, consisting of 

 gray and green schists, and forming so large a part of the entire thickness, 

 have been merely referred in a general way to the Paleozoic. In their 

 typical locality they appear to be distinctly traceable on their line of strike 

 into contemporaneous diabase and diorite rocks, which are often agglom- 

 erates, and pass into volcanic ash rocks, where their constituents become 

 finer. The peculiar lithological character (which, taken by itself, might be 

 supposed to indicate that the rocks should be classed as upper parts of the 

 Archean) of these Adams Lake schists is thus believed to depend chiefly on 

 the dynamic metamorphism resulting from extreme pressure which has 

 affected the volcanic components of the Paleozoic, where these have been 

 included in the strict flexures of the mountain region of the Gold system. 

 No direct paleontological evidence is, however, forthcoming with respect to 

 the age of the rocks of this first column of the table. 



The third column in the table represents Mr. McConnell's published sec- 

 tion in the Rocky Mountains proper, in which certain horizons, ranging up- 

 ward from the lower Cambrian, are definitely fixed by fossils. It was found, 

 in working out the section in this part of the Rocky Mountains, that a consid- 

 erable diflference exists betw,een the section of the eastern as compared with 

 that of the western part of the range, the present width of which (whatever 

 that originally occupied by the rocks composing it may have been) is about 

 sixty miles only. The particular feature of this change which is interesting 

 in the present connection is that observed in the Castle Mountain (Cambrian 

 and Cambro-Silurian) group, which, although it is on the east essentially a 

 limestone formation, is found on the west to consist in laTge part of greenish 

 calc-schists and greenish and reddish shales and slates. ''"^ No granitic rocks 

 or true crystalline schists are seen in any part of this section. 



The section represented by the middle column in the table is that now 

 obtained for the Selkirks. It occupies, geographically, as it does in the table, 

 a position intermediate between that of the eastern border of the interior 

 plateau and that of the Rocky Mountains. In this, as in the section given 

 in the first column, no horizons have yet been fixed paleontologically, and the 

 position given to the rocks therefore depends principally on the comparison 

 of the section with that known in the Rocky Mountains proper. It is prob- 

 able, from the composition and condition of the rocks, that they may yet be 

 found to hold fossils; but in the meantime it is believed that the lithological 



* Annual Report Geol. Surv. Can., 1886, pp. 24d, 25d. 



