Page:The Journal of geology (IA journalofgeology21894univers).pdf/465

around Kekequabic lake is a pyroxene granite, and associated with it is peculiar pyroxene-granite-porphyry. The intrusive character of the granite is particularly well shown between Sec. 31 and 32, T. 63 N., R. 10 W., near Clearwater lake, and in the S. E. ¼ of the S. W. ¼ Sec. 26, T. 64 N., R. 9 W., on the west shore of Snow Bank lake. Along the Kawishiwi river, the rocks mapped comprise gabbro, syenite, mica-schist, graywacke, etc.; greenstone and quartz-porphyry. The gabbro is the most recent, and covers part of the older rocks. The syenite is older than the gabbro, and is younger than the greenstone and mica-schist, both of which it cuts. The mica-schists, graywackes, etc., are vertical, and have a general east northeast strike. These have been formerly mapped as belonging to the Vermilion series, but there seems to be good reason for putting all of this type of rock in the area mapped into the Keewatin. The greenstone is presumably of Keewatin age, and is probably younger than the mica-schists, graywackes, etc. Quartz porphyry dikes are found cutting the greenstones in several places, but they have not been seen in the other rocks in the immediate vicinity.

Comments.—The conclusions of this report differ from the general succession given by Professor Winchell in the fundamental point that there is no gradation betwene the granitic rocks and the metamorphosed sedimentary rocks. Also all of the metamorphosed sedimentary rocks are regarded as belonging to the Keewatin (Lower Huronian?) while the Vermilion schists are not found. If there now exists in this area the original basement upon which the sedimentary rocks were deposited, this has not been found. It is of course possible that such a Basement Complex does not exist in the Kawishiwi river area, the one which was most closely studied, nor even in the entire region, but this is not thought probable.

Winchell (H. V.)^[1] describes the Mesabi iron range of Minnesota. The range extends from the Canadian boundary, a little south of west to the Mississippi river, a distance of 140 miles or more, but is concealed for a part of this distance by the later gabbro overflow. The succession of the Mesabi in descending order is:

The granite of the Giant's Range is bounded on the north by a belt of crystalline mica-schists and hornblende-schists, and on the south seems to