OF THE ROCKS OF LAKE SUPERIOR. 241 
396. 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. 
399. 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 brecciated ; 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—eranular quartz, containing native copper. 
374. Native copper, associated with prehnite, laumonite, calcareous spar, quartz, 
~ and some undetermined zeolites. 
31 
