OF THE ROCKS OF LAKE SUPERIOR. 237 
with a tint of grayish green. In some places, contains flesh-coloured felspar. Wea- 
thers with a slightly rough, iron-shot surface. 
279. Greenstone—colour, grayish black; the felspar honey-coloured, some of the 
crystals large; some large crystals of hornblende. 
280. Greenstone—very coarsely crystalline. 
281. Decomposing crystals of hornblende in a felspar paste. 
282. Siliceo-argillaceous shale—highly metamorphosed; colour, dark purplish 
gray; thinly laminated; same as No. 100 ; rings like phonolite when struck. Is 
associated with basaltic beds; joints contain stilbite. 
283. Syenite (?)—colour, flesh-red ; highly crystalline ; the felspar predominates ; 
weathers slowly, and with a tolerably even surface. Differs little, if at all, from 
the highly metamorphosed beds of No. 213. 
284. Greenstone—colour, very dark gray, almost black ; minutely crystalline ; 
the hornblende predominates. 
285. Siliceo-argillaceous shale ; highly metamorphosed ; colour, brick-red ; very 
compact; fine-grained; almost homogeneous; resembles jasper; contains a few 
small lumps and scales of quartz; fracture uneven; weathers with a smooth sur- 
face; no incrustations; very hard. Some of the beds are less compact, and inclined 
to be shaly. 
286. Basaltic rock—colour, dark gray, almost black; is jointed, and shows a 
laminar structure; a thin crust of iron rust between the laminze, and in the joints ; 
is generally homogeneous, but exhibits, in some places, minute crystalline points. 
Weathers with a smooth, black surface. This rock is separated from No. 287, by 
beds of amygdaloid. 
287. Volcanic grit—colour, reddish gray, with a slightly greenish tint; fine- 
grained; tolerably compact; many grains of thalite (?) disseminated through 
it. This rock bears considerable resemblance to some of the altered sandstones. 
Contains numerous grains of peroxide of iron. 
288. Metamorphosed siliceo-argillaceous shale—colour, brownish red; amygda- 
loidal, the cells filled with zeolites; has a very rough, hackly fracture; shows 
evidences of thin lamination, rendered indistinct by metamorphic action. 
289. Metamorphosed shaly sand-rock, or volcanic grit (?)—colour, brick-red ; 
slightly amygdaloidal; contains a few rounded siliceous pebbles. 
290. Metamorphosed sand-rock—colour, grayish red; compact; contains many 
minute crystals of yellow iron pyrites. Belongs to the finer grit beds. 
291. Basaltic rock—fine-grained ; colour, dark gray, with a slightly reddish tint. 
292. Argillaceous iron ore. 
293. Basaltic rock—fine-grained ; colour, dark purplish red; fracture, smooth, 
conchoidal; nearly homogeneous; has a few minute crystalline points. 
294. Metamorphosed siliceo-argillaceous shale; colour, red; fracture, sharp, 
uneven; very hard; has a baked appearance; contains occasional small crystals of 
felspar. Resembles the “Great Palisade” rock. In contact with No. 293. 
295. Same as No. 294—less compact; shaly; has a greater resemblance to the 
quartzites. The less altered portions show a granular structure. 
