. The Canadian naturalist and geologist. Natural history -- Periodicals. 1S67.] MACFARLANE—GEOLOGY OF LAKE SUPERIOR. 183 and the latter varies from 1-1° to 20° north-westward. It is in t erst ratified with a small-grained granitic gneiss, containing much less mica than the last—about one-twentieth only,—no tricliuic felspar, and having a specific gravity of 2-71 to 2-72. The same granitic gneiss intersects the characteristic gneiss in veins, and both of these rocks are cut by a coarse-grained granite, almost destitute of mica, and completely so of schistose structure. The strata of the gneiss
. The Canadian naturalist and geologist. Natural history -- Periodicals. 1S67.] MACFARLANE—GEOLOGY OF LAKE SUPERIOR. 183 and the latter varies from 1-1° to 20° north-westward. It is in t erst ratified with a small-grained granitic gneiss, containing much less mica than the last—about one-twentieth only,—no tricliuic felspar, and having a specific gravity of 2-71 to 2-72. The same granitic gneiss intersects the characteristic gneiss in veins, and both of these rocks are cut by a coarse-grained granite, almost destitute of mica, and completely so of schistose structure. The strata of the gneiss are much contorted in various places. The intersecting granitic gneiss and granite are almost equal in quantity to the gneiss itself; and although they occur as irregular veins, they are, at the point of junction, as firmly united with the gneiss as any two pieces of one and the same rock could well be. Figure 3 is intended to represent the relations observable at Goulais Falls. Between Goulais Falls and the Fie. 3. a ==. a. Gneiss. | b. Granitic gneiss. | c. Coarse-grained granite. point where the line of junction between the Laurentian and Huronian rocks crosses Goulais River, there are numerous exposures of gneissoid rocks, but characteristic gneiss is of rare occurrence among them. At several places hornblende schist, in fragments, is observed enclosed in a gneissoid granite. Some of them are longer than others, and have their longer axes running N. 50° to 60° W. Hand specimens of the enclosing granite show little or no mark of foliation, but when seen in. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Natural History Society of Montreal. Montreal, Dawson
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