0 F T II E ROCKS O F L A K E SUP E R I O R. 



247 



easily divisible into thin laminae ; very fine-grained ; homogeneous; magnesian. It 

 might properly be called a talcose argillaceous slate. 



451. Same as No. 450 — colour, gray and greenish gray; very thinly laminated, 

 with thin scales of talc between the lamina?. It has an eminently soapy feel, and, 

 in some of the beds, might be set down as talcose slate. It is easily scratched with 

 the nail, which leaves a white streak. It is traversed by veins of No. 452. 



452. White crystalline quartz, with particles of flesh-red felspar, crystals of car- 

 bonate of lime, and nodules of iron pyrites. 



453. Argillaceous slate — colour, grayish blue ; very compact, so much so as to 

 lose almost entirely its fissile character. The marks of fine lamination, however, 

 are never entirely obliterated, and, occasionally, the rock can -be split with difficulty 

 in the direction of the lamina?. The fracture is somewhat splintery. In some of 

 the joints it is discoloured by iron-stains, but in other cases the joints become 

 grayish white, under the influence of atmospheric agents. The texture is even and 

 fine-grained. 



454. Greenstone — colour, grayish black; the hornblende predominates largely; 

 fine-grained ; minutely crystalline ; resembles the dolerites. 



455. Greenstone — colour, grayish ; amygdaloidal ; the cells, which are numerous, 

 contain quartz, epidote, copper pyrites, and some zeolites. In structure and colour, 

 it resembles the greenstone trap of Black River. 



456. Greenstone — massive; tolerably fine-grained ; the felspar of a honey-yellow 

 colour, in grains and in crystals ; colour, dark greenish gray, with a yellowish tint. 

 Weathers with a rough iron-shot crust. 



457. Red sandstone conglomerate, precisely like those of the north shore of Lake 

 Superior, which have been subjected to metamorphic influences. The prevailing 

 colours of the materials are red and gray ; and, like the Lake Superior conglome- 

 rates, it has many zeolitic and other minerals developed in small cavities and inter- 

 stices. The larger pebbles are mostly of sandstone, some of them much altered. It 

 contains a few greenstone pebbles. 



458. Sandstone — fine-grained; colour, from dark pink to deep brownish red; 

 very ferruginous ; grains round and angular, mostly angular ; many minute glisten- 

 ing points, which appear to be crystals of calcareous spar. Felspar grains seem to 

 predominate. 



459. Metamorphosed red sandstone — tolerably fine-grained and compact. It 

 contains occasional cells filled with thalite. In its general characteristics it re- 

 sembles No. 485, and many of the rocks on the north shore of Lake Superior. It 

 is, probably, a volcanic grit. 



4G0. Metamorphosed siliceous shale. This rock resembles many of those on the 

 north shore of Lake Superior, and particularly some of the slaty beds of Kinechi- 

 gakwag Creek. (See No. 425.) A portion of the beds is a trap breccia, containing 

 much epidote ; while other beds are porphyritic, and contain many fragments of 

 flesh-coloured felspar. In the mass, it might be set down as a slaty greenstone. 



461. Greenstone — colour, greenish gray; fine-grained; crystalline. 



462. Red sandstone — fine-grained; compact; flesh-coloured; contains small lumps 

 of ferruginous clay. 



