REPORT OF TEE CHIEF ASTRONOMER 321 



SESSIONAL PAPER No. 25a 



•correlate the limestone in place with the limestone fragments in the breccia 

 -on each side of the valley, and the formation, including the limestone and 

 -chert, is tentatively placed in the Carboniferous system. 



Carboniferous Limestone in' the Rossland Mining Camp. — In 1905 Brock 

 discovered in a limestone band interbedded with andesitic greenstone at the 

 O.K. mine, four miles north of the last mentioned locality, certain fossils which 

 have been referred to Carboniferous species. 



Sutherland Schistose Complex. — A group of metamorphic rocks, exposed 

 "in the railway cuttings between Cascade and Coryell stations, were sectioned 

 during the season of 1902. Although nearly a week was spent on the section, 

 the results of the structural study were meagre. The oldest rooks of the section 

 consist of highly crystalline schists of sedimentary origin. With these are 

 associated many irregular bands of gheissic, gabbroid rocks and amphibolites, 

 and sheared hornblende porphyrites, all of which represent greatly altered basic 

 intrusives. The metamorphosed sedimentary rocks are now represented by 

 garnetiferous schist, sericite schist or phyllite, biotite-epidote schist, actinolite- 

 biotite schist and andalusite-biotite schist. Massive, often brecciated, greenish 

 quartzite and at least two large pods of white to light gray marble are inter- 

 bedded with the schists. 



Structurally the complex is characterized by utter confusion. Neither 

 bedding-planes nor planes of schistosity preserve a steady attitude for more 

 than a few score or hundreds of feet together. The section is located in a zone 

 of maximum dislocation, a zone now followed by the deep trough of Christina 

 lake. The immense alteration of these formations is further due to the intru- 

 sion of numerous large bodies of acid and basic igneous rock, including various 

 gabbros and peridotites as well as the great Coryell syenite batholith. 



No trace of a fossil was found in the sedimentaries and it is still impos- 

 sible to correlate them with known horizons. The quartzite and limestone 

 associated with the schists are, in general, similar to the quartzite and crinoidal 

 limestone of Little Sheep creek valley and to staple phases of the Pend 

 D'Oreille group. All of them are possibly of Carboniferous age. The gabbroid 

 and peridotitic masses cutting the schists are evidently of more recent dates ; 

 some of them show neither crushing nor even appreciable straining under the 

 microsccpe. Three of these basic intrusive bodies will be briefly described 

 below; a microscopic description of the schists themselves is scarcely warranted 

 by any special petrographic interest they possess. 



Summary . — In conclusion, it may be noted that some at least of these old- 

 looking metamorphosed sediments are almost certainly of Carboniferous age. 

 Others may be either pre-Carboniferous or else Triassic, if not as late as Jurassic. 

 For the present the writer follows the tradition of McConnell and Brock in 

 placing all of these formations in the Paleozoic. Whatever the age of the sedi- 

 ments, some of them seem to be contemporaneous with thick, massive greenstones 

 .and metamorphosed ash-beds of andesitie sort, and it is highly probable that the 

 25a — vol. ii — 21 



