292 J. P. Kimball on Iron Ores of Marquette, Michigan, 
the north and south with intercalated beds of quartzite, potash, 
feldspar and hornblendic schists, the whole dipping uniformly 
from the axes of elevation. Hornblende sometimes was seen to 
replace mica, forming a light grey syenite. The granite south 
of the metamorphic belt is generally made up of feldspar and 
quartz, mica being almost always wanting, or very sparingly 
resent. Feldspar is the most predominating mineral, large 
odies of flesh-red orthoclase being of common occurrence. Two 
systems of dykes, and extensive intrusive masses of greenstone 
—the larger of a bearing uniform with the axes of elevation, 
the smaller being N.E. and S.W.—were indicated as oceurri 
throughout the distribution of both belts. These are intersected 
yee 
Foster & Whitney as Azoic, an equivalency with the Huronian 
series of Canada." Such a tendency appears to be due to the 
investigations upon the south shore of Lake Superior of “ 
The lines of demarcation between the Azoic strata and the 
granite, as laid down by the Land District Survey, appeat 
S 
. Foster & Whitney ; ibid, chap. iii. 
* Geol. of Canada, 66,596; Dana’s Manual of Geology, 148. 
* This Journal, [2], xxi, 394. 
