ARCHEAN 03 



mica-schist of the North Thompson, etc.," and reco<;nized from the first 

 hy him as " theokiest rocks observed in the country." It was not, liow- 

 ever, till 1889 that much further information was gained regarding these 

 old rocks, when good sections of them were found by the writer on 

 Kootenay lake, and as they were also well develo})ed on Shuswap lake, 

 the name Shuswap series was proposed for them.-i^ The Shuswa]) rocks 

 proper evidentl}" represent highly metamorphosed sediments with per- 

 haps the addition of contemporaneous bedded A'olcanic materials. They 

 are grayish mica-gneisses, with some garnetiferous and hornblendic 

 gneisses, glittering mica-schists, crystalline limestones and quartzites. 

 Gneisses in association with the last-mentioned rocks often become 

 highly calcareous or silicious and contain scales of graphite, which are 

 also often present in the limestones. These bedded materials are, how- 

 ever, associated with a much greater volume of mica-schists and gneisses 

 of more massive appearance, most of which are evidently foliated plu- 

 tonic rocks, and are often found to pa.ss into unfoliate'd granites. The 

 association of these different classes of rocks is so close that it may never 

 be })ossible to separate them on the map over any considerable area. 

 The granites may often have been truly eruptive in origin, but the fre- 

 quent recurrence of quartzites among them in some regions indicates 

 that they are, at least in part, the result of a further alteration of the 

 bedded rocks. f 



Thus, up to the present time, the Shuswap series has been made to in- 

 clude this entire complex mass of cr3^stalline rocks, although it might be 

 more appropriately restricted to the originally bedded members. These, 

 it will be observed, now very closely resemble those of the Grenville 

 series of the province of Quebec, the resemblance extending to the 

 nature of their association with the foliated rocks, which in turn closely 

 resemble the so-called " Fundamental Gneiss " of the same region. The 

 original materials and the conditions of alteration to which they have 

 been subjected have in both localities been almost identical, producing 

 like results. The age must be approximately the same, but the distance 

 is too great to admit of any precise correlation on lithological grounds. 



When the ruling lines of strike or foliation of the Shuswap are laid 

 down, they are generally found to be parallel with each other in each 

 particular region, but to run in great irregular sweeping curves over the 

 face of the map as a whole, and sometimes to surround unfoliated granitic 

 areas in a concentric manner, the whole aj^pearance being very much 

 like that met with in some parts of the Laurentian country in the east. 



♦Annual Report, Geol. Surv. Can., vol. iv (N. S.), p. 29 B. The name Kootanie (or Kootenay) was 

 preoccupied. 

 fCf. Shuswap map-sheet, Geol. Surv. Can., 1898. 



