O F T HE ROCKS OF LAKE SUPERIO R. 



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356. Metamorphosed sandstone — fine-grained; slightly amygdaloidal, the cells 

 filled with thalite ; colour, red. 



357. Metamorphosed siliceo-argillaceous shale — colour, dark gray, with a purplish 

 tint ; fine granular. In some places has a basaltic look. 



358. Metamorphosed red sandstone — fine-grained; compact; colour, dark pur- 

 plish red. Some of the seams and joints are bluish-coloured, like cracks in an over- 

 burnt brick. Same as No. 356, but more highly metamorphosed. 



359. Volcanic grit — colour, dark purplish red; numerous grains and lumps of 

 thalite. Has an irregular nodular fracture; ferruginous. Weathers with a smooth, 

 brownish-red surface. 



360. Metamorphosed earthy sand-rock — slightly brecciatcd ; very irregular frac- 

 ture ; amygdaloidal cells filled with a green mineral, probably chlorite ; and the 

 same mineral is distributed through the rock in patches. Colour, reddish gray, 

 spotted with green ; fine-grained. Has rather a shaly structure in some places. 



361. Metamorphosed sand-rock — colour, dark reddish brown ; very compact ; fine- 

 grained; rough, irregular fracture. Less altered than No. 360. 



362. Greenstone — colour, greenish gray ; minutely crystalline ; amygdaloidal, es- 

 pecially near the rock which it traverses ; the cells contain zeolites, sometimes sur- 

 rounding a nucleus of calcareous spar. 



363. Metamorphosed quartzose shale — colour, dark gray; tolerably thinly lami- 

 nated ; contains small nodules of crystallized quartz. 



364. Metamorphosed earthy sand-rock — colour, grayish red; amygdaloidal, the 

 cells filled with zeolites. Some of the beds are soft, disintegrate easily, and re- 

 semble baked clay. 



365. From a vein — contains fragments of rock, calcareous spar, some zeolites and 

 rock crystal. 



366. Red sandstone — white bands; very fine-grained. 



367. Native copper — associated with quartz and zeolites. 



368. Hornblendic slate — same as No. 355. 



369. Native copper and malachite, in quartz. The vein also contains large 

 masses of prehnite, some laumonite, and other zeolites. 



370. Anorthite rock — colour, in hand specimens, greenish yellow; in the mass, 

 greenish black ; highly crystalline, many of the crystals half an inch long, and some 

 of them longer. Fuses to a white enamel. Some portions of the rock contain a 

 few grains of hornblende. Same as No. 328. 



371. Basaltic rock — colour, greenish black; non-crystalline; fracture smooth, 

 disposed to be conchoidal. Weathers with a smooth, even surface, covered with a 

 very thin greenish scale. 



372. A seam in No. 370. Decomposing felspar, filled with large grains of quartz, 

 and hardened into a very compact rock. Colour, yellow, with numerous dark points, 

 made by the quartz and a few grains of hornblende. 



373. Veinstone — granular quartz, containing native copper. 



374. Native copper, associated with prehnite, laumonite, calcareous spar, quartz-, 

 and some undetermined zeolites. 



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