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junction of the gneiss and green slates, though its actual contact w ith 29 
either was not seen. | ae : ‘i. 
91. A mile still further eastward, at the extreme north-eastern : 
corner of the lake, the Winnipeg River, may be said to begin, in a + a 
cascade, which falls northward, across the junction of the Laurentian me ee 
Huronian series, through a narrow passage between rocky cliffs. At the a 
fall, the rock is quite similar to that seen at Rat Portage proper, being a x 
fine-grained, hornblendic slate, much hardened and of greenish colour ; dip 
N.10° W.< 45°. Just below the fall, the red gneiss again suddenly appears _ 
with a dip N. 18° E. < 78°. The line of junction of the formations obtained = 
by protracting that at the fall, to that at Rat Portage proper, coincides 
remarkably with that already obtained by observation on a more limited 
scale at the latter place, and follows the summit of the ridge which 
separates the! river from the lake. A rock quite similar to the erup- 
tive greenstone seen at the rapids, is again visible at the entrance 
to the gorge of the fall. If it really belongs to this mass, it must toward — 
the eastern end depart somewhat from the actual line of junction, and | 
may possibly attain this position by following the strike of the slates. 
92. Notwithstanding the close accordance of the strike of both series 
of rocks, and the direction of the line of junction, the evidence appears to 
be nearly conclusive, that the two formations are here brought together 
by a fault, with an extensive downthrow southward. If they are thus in 
contact merely by sharp folding, the relative position must be reversed, 
as the dips would carry the slate series below the gneiss; and it is diffi- 
cult to imagine such extensive flexures taking place without imparting 
a yet more highly altered aspect to the schists than that which they now 
have. The straightness of the line, and the sharp separation by it of 
the two kinds of rock, also points in the same direction. | 
93. The change in aspect of the country to the north and south of this 
great fault, is very sudden and striking. Southward, the shores of Clear- 
water Lake are generally characterized,—where not caused to assume 
unusual boldness by hardening eruptive rocks,—by low, gently-rounded 
rocky hills, which in their natural state bear a good growth of trees. 
These hills, even when they have been burned over, retain a sufficiency 
of soil to cause the re-appearance within a year or two of a dense uader-— 
growth, giving them a uniformly green aspect from a distance. North 
of the fault, the Laurentian rocks form a succession of boldly rounded and 
tumultuous hills, showing a great surface of bare rock, which may never — 
have been covered by trees, but which more probably has had forest and _ 
