The Michipicotcii Huroiiioji Area. — U'illiiioff. 17 
( 1 ) Southeast of the Alichipicoten river and reaching with- 
in nine miles of this area is an unbroken mass of granite-gneiss 
which extends 120 miles southeast to the original Huronian, 
If there is any Laurentian in the country, this must represent 
part of it. This Laurentian area extends six miles farther 
northwest in broken contact with the green schists. Three 
miles farther the area under discussion bears a similar relation 
to the same schists, though between there lies the trough filled 
with Lower and Upper Huronian sediments. 
(2) The two areas are alike lithologically, and might well 
be of the same age. 
(3) The large southern area is in eruptive contact with a 
conglomerate south of Michipicoten falls. This conglomerate 
has not been studied, and its age is unknown, but it cannot be 
earlier than Lower Huronian and is more likely Upper Huron- 
ian, as no Lower Huronian conglomerates have yet been recog- 
nized in the district. Accordingly, this Laurentian is at least 
post-Lower Huronian, if not later, which makes the equivalency 
in age of the two areas at least probable. 
It will be urged that if all the granite-gneiss of the region 
is post-L'pper Huronian there is no floor on which the early 
volcanic flows could be laid down. Possibly Lawson's sugges- 
tion regarding the Rainy Lake district applies here also. In 
both regions are masses of green schists almost vertical, sur- 
rounding a batholith of granite in eruptive contact with them. 
Lawson held that if the granite was the original crust on which 
the volcanics had been deposited, it had afterwards been re- 
fused. 
At the Dore the pebbles of granite were probably derived 
from a mass now beneath the waters of Superior. Not only do 
they dififer from the known cx])<)sures of granite to the north, 
but the cherty pebbles certainly came from a belt on the south,, 
only a few hundred feet of which is now visible on the penin- 
sula of Gros Cap. Tlie.way in which the conglomerate encir- 
cles the granite suggests that originally this central area was 
a water basin. Ilic conglomerates surrounded the shores, 
and doubtless finer sediments occupied the center of the depres- 
sion. The granite mass was then upheaved, and the schistos- 
ity produced in the lavas and sediments through which it ex- 
truded. In places it is now foimd in contact with the Upper 
