
44 B. N. A. BOUNDARY COMMISSION. 
angle. This rock was not observed on the east side of the lake, but may 
very possibly be represented there. 
87. North of this, another extensive belt of slate rocks crosses the 
lake, but the strata in this region are not regular, and it is difficult to cor- 
relate the beds except in a general way. The first rock observed beyond 
the conglomerate, on the west side, was a close-grained grey schist, with a 
strike of N. 55° EK. A mile beyond the conglomerate, similar schistose 
rocks were observed, and again vertical. Rough, green, and rather soft 
chloritic schists then appear, and are the predominant rocks till within 
about half a mile of the north-west end of the lake. On the eastern side 
of the lake, near where the strike of the last-mentioned greenstone would, 
bring it to the shore, and probably in immediate proximity to its continu” 
ation, is a hard green altered rock,with epidote and quartzose segregations, 
and no determinate dip or direction. North of this, thinly laminated 
green chloritic slates occur. Among these, on an island about three 
miles southward from the Hudson’s Bay establishment at Rat Portage, a 
vein a foot or two in width was observed to pass, apparently conforming 
with their strike. The vein-stone was white, but had the appearance on 
the surface of being stained by the decomposition of some ore of copper. 
It was, however, too boisterous to land with the canoe at the time. 
Northward, similar rocks continue, but become harder. A mile from 
the Hudson’s Bay Post, they were observed to have an east and west 
strike and to be quite vertical. About half a mile south of the Post, 
there is a somewhat extensive belt of greenstone-like rocks, which, 
though conglomeritic in places, do not show that character persistently, 
but appear to graduate into compact homogeneous diorite. This belt 
seems to cross the lake just south of its extreme northern shore, and to 
strike into the western side, immediately south of the entrance to Rat 
Portage proper. There its rocks occupy a breadth of perhaps half a mile, 
and are separated from the Laurentian by a belt of slaty rocks of about 
the same width. On this side they appear as compact diorite, but show 
cleavage planes, and resemble the sometimes conglomeritic greenstone of 
the west shore. 
Geology of the Vicinity of Rat Portage. Junction of the Huronian 
and Laurentian. 
88. The Winnipeg River, on leaving the Lake of the Woods, falls 
into an elongated basin, which lies transverse to its general direction and 
stretches westward nearly parallel with the shore of the lake for some 

fe 
4 
‘ 
ee ee ee ee ee ee ee 
