



green, with irregular grains of iron pyrites; and show large isolated green- 
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B, N. A. BOUNDARY COMMISSION. % Be | 

45. The gneiss above described, extends along the shore southward fe 3 
about a mile and a half, and then sinks below the level of the water, and cy q a 
for about fifty miles, following the coast-line,—which treads westward and | 
forms two deep bays,—no rock is seen in place; the shore consisting of sand — ‘ 
and wide-stretching grassy swamps. The rock next appears forming ie a 
the north-eastern point of the southern promontory of the lake, which is — “4 Xe 
about eighteen miles due south of the last mentioned exposure. It is very eg ° 
possibly a much altered gneiss, but assumes the appearance of a fine- — vi 
grained granite, very compact, and pinkish-grey in colour. It is much — i aa 
broken up by intrusive diorite dykes of large size, which have a general _ Bs. r 
direction of from N. 20° E. to N. 40° E. These are very compact, dark- 




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ish-white blotches which give the rock a roughly porphyritic aspect, =~ 
and are composed of felspar crystals, which have undergone fracturein 
several directions since their formation. A small rocky islet, about a 
mile and a half north-east from the point, is composed of a similar an 
material ; it was covered, when visited, with nests full of young cormor- _ 
ants (Graculus dilophus). Both these diorites essentially resemble that 
composing an island near the first exposure of Laurentian rocks south 
of the Angle Inlet. ; 
46. Four miles eastward, the north-eastern point of the southern pro- 
montory is found to consist of rock in place, which extends for more than 
a mile along the shore. It consists of thinly stratified gneiss and horn- 
blende schist, much broken up by small faults, and twisted, but showing 
a general dip of from N. 50° EK. to N. 70° E., at angles of 50° and 
upward. a 
47. From this point to the vicinity of Rainy River no rock appears. ‘a 
Near the mouth of the river, limestone has been reported to exist, but I 
did not find this rock except as scattered boulders, in which form it is 
common along the whole southern border of the lake. xe 
48. A few miles north of Rainy River, the Laurentian rocks again rise — 
above the level of the drift, as hornblende schists, associated with thin- fee), 
bedded gneiss. Where first met with, their strike is N. 85° W., and the 
dip southward at a high angle. At two points a little further north, the a 
strikes were found to be N. 73° W. and N. 78° W. respectively. The 
hornblende schists are generally composed of black hornblende and white 
felspar, and are fine grained and thinly bedded. In some places, however, 
the hornblende changes toa rather light green. The rocks are traversed by 
numerous sinuous red felspar veins, and in minor cracks show streaks of 




















