310 J.D. Whitney on the Huronian and Laurentian 
The Huronian beds are chiefly made up of a compact and 
almost vitreous quartz-rock, in no respect resembling the sand- 
stone of the south shore of Lake Superior, even where the latter 
is most hardened and metamorphosed by immediate contact with 
the trap. The beds of conglomerate in the Huronian series are 
of very subordinate importance and entirely differing in charae- 
ter from the great conglomerate bands associated with the igne- — 
ous rocks of the south shore of Lake Superior. In the former 
* : e Superior there are some con- 
siderable areas in which important masses of interstratified green- 
stone exist without amygdaloid, while white sandstones are pres- 
on the Canadian side of Lake Superior itself.”* : 
Tn order to arrive at a better understanding of the matter m 
question, we will briefly notice some of the most important facts 
in the geology of the north shore of Lake Superior, where the 
phenomena are much more complicated and difficult to decipher 
ae iver Canada, Report on the North Shore of Lake Huron; 1849, 
