
ay 
ry. 
LAKE OF THE WOODS.—LAURENTIAN. 25 
cast of Birch Creek, a well stratified and thinly bedded gneiss rock is 
exhibited, having in some layers a green colour from hornblende or epidote. 
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Its strike is N. 50° E. Other exposures of similar rocks, with a general 
accordance of strike, were seen between the last mentioned place and the 
North-west Angle. 
42. Near the upper part of the North-west Angle Inlet, rock exposures 
are extremely rare ; but this region is also apparently underlaid by Lauren- 
tian. A few hundred yards northward from the Reference Monument, and 
in the midst of a dense wood, a low rounded mass of dark gneissic rock 
rises above the general level. It holds apparently both hornblende and 
mica, which are arranged in thin and regular laminae, and is nearly 
vertical with a strike of N. 70° E. On the opposite side of the inlet, in 
the entrance to a reedy creek, a few yards of a compact greyish-black 
micaceous rock appears nearly at the water level. Its attitude is not 
clear, but it is traversed by two quartz-felspar veins, each about eighteen 
inches wide, with a course of S. 75° E. 
43. The rocks in the vicinity of the North-west Angle Inlet are thrown 
into some confusion by the presence of a great granitic and syenitic intrusive 
mass, more fully noticed on a subsequent page. South of this intrusive 
mass on the west shore of the lake, the first rock clearly Laurentian, 
occurs about five miles southward from the entrance of the Inlet, and about, 
a mile from the southern end of the granitic peninsula, known as Flag 
Island. The rock might here undoubtedly be called a granite, and in some 
parts is quite coarsely crystalline, with large and prominent felspar crystals. 
The whole, however, shows a foliated structure, and other remains of 
stratification parallel to the direction of this, are to be seen in places. The 
general line of strike thus indicated, is nearly east and west, turning 
sometimes a little north of east. 
44. This rock is traversed by dykes and veins in many places, and 
one instance of curiously complicated intersection of these was observed. 
The oldest intrusion is a vein of red felspar, but a few inches thick, and run- 
ning about north-east. This is divided by adyke three or four feet wide, of 
greenish diorite, which includes fragments of the much-altered gneissic 
rocks, and gives off some diverging branches. A thin seam of very dark 
hornblendic, diorite of still later age, cuts across both these, and is in turn 
intersected by an irregular vein of red granite. Lastly, a movement 
parallel to the direction of the largest diorite dyke, and subsequent to all 
the others, is indicated by a crack-mark, along which the granite vein has 
been slipped. (Plate I.) 
