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LAKE OF THE WOODS—GENERAL CONCLUSIONS. 49 
the folds of the Huronian rocks in Clear-water Lake ; and is probably due 
to an uplift of hard lower gneiss rocks by action at the second period, 
subsequent to that which has here been the chief agent in folding the 
Laurentian strata of this part of the lake. 
99. Flexures corresponding pretty closely to those above indicated, 
are found affecting Laurentian and Huronian rocks at very distant locali- 
ties. Sir W. E. Logan, in speaking of the Laurentian of the Ottawa region, 
says:—‘ The arrangement presented by the outcrop appears to depend 
on two sets of undulations, the axis of the one running in bearings ap- 
proaching north and south, and of the other in bearings nearly east and 
west, the latter apparently related to the oldest system of dykes. The 
north and south undulations appear to be the more important and more 
numerous of the two, giving to the lines of outcrop in that direction the 
greater number of repetitions and the longer stretches. For about twenty- 
five miles from the Ottawa and North Rivers, the bearing of these axis is 
about N. 10° E.”* Mr. Henry G. Vennor, in discussing the general rela- 
tions of the Laurentian in the County of Hastings and vicinity, in Ontario, 
remarks :—“ The geographical distribution of these rocks shows a series 
of north-east and south-west undulations, throwing the upper division into 
long narrow troughs in these directions. These undulations are crossed 
at irregular intervals by geological elevations which separate the ends of 
the troughs, and by depressions which unite their sides.” + The latter, 
on reference to his map of the district, are seen to have north-westerly 
courses. The rocks of supposed Huronian age which are now being found 
by the Geological Survey among those of Laurentian date, in widely 
separated localities, also run in belts with general north-east and south- 
west bearings. It would thus appear, that the disturbances affecting the 
Laurentian and Huronian formations have not only been very violent, but 
very uniform in their action over a great extent of country, and indeed 
to have operated on an almost continental scale. 
100. The granitic mass of the North-west Angle and vicinity, which, 
as already mentioned, is of post-huronian age, if it runs eastward through 
the promontory separating Clear-water and Sand-hill Lakes, as suggested 
by Dr. Bigsby, probably closely follows its northern edge; as in treating of 
this part of the border of the lake, Dr. Bigsby mentions several districts 
of five or six miles in length each, showing a rock resembling syenite. 
This term might well be used in describing large areas of the mass where 

* Geology of Canada., p. 43, + Report of Progress Geol. Survey of Canada., 1870, p. 145. 
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