THE 
AMERICAN GEOLOGIST 
Vol. III. MARCH, 1889. No. 3 
CONGLOMERATES ENCLOSED IN GNEISSIC TERRANES. 
By Alexander Winchem,. 
The region which is the special subject of the present article 
lies on and near the International boundary, northwest of Lake 
Superior. It is embraced within the great Archaean area of the 
North, between the parallels of 47'^30' and 48^^30' north latitude, 
and the meridians of 90"^ and 91*^30' west longitude. The sui-- 
face is occupied by gneisses, crystalline schists and earthy 
schists, all standing quite conformably, in an attitude nearly 
vertical, and trending east-northeast. Occasionally, over limited 
areas, the gneisses appear destitute of bedding or foliation, and 
for this reason, and also the unimportance, for geological 
purposes, of the distinction between gneisses and ordinary 
ma.ssive granites and syenites, I have freq\iently recorded as 
"granite," the crystalline masses underlying the crystalline 
schists. For similar reasons, usage has affixed the name 
"granite" to rocks in which the dark mineral constituent 
is hornblendic, as well as to those in wdiich it is micacic. With 
this understanding, it may be stated that the region here con- 
sidered extends into and embraces portions of three granitic 
regions which superficially appear to be wholly separated from 
each other by earthy schists. The most easterly I have els(^- 
where described as the "Saganaga granite;" the most westerly. 
