

66 B. N. A. BOUNDARY COMMISSION. 
stone, and magnesian limestone. It is one of convenience only, and | 
founded on the different colours of the zones as they appear in the moun- 
tain sides, | 
140. The trap E. is still important at this place, but is not so thick 
as in the Mt. Yarrell sections. It is dark-purplish in colour, and full of 
irregular amygdaloidal cavities, which are lined with green chloritie 
matter, and generally filled with white calcite. It overlies the great 
limestone, as before. 
Eastern Front of the Water-shed Range, Mt. Wilson and Chief Mountain. 
141. Northward from the entrance of the South Kootanie Pass, along 
the eastern side of the mountains, for at least twenty-five miles north of 
the Line, the rocks exposed are similar to those already described. All 
the beds of the eastern ridges appear to dip westward, or west-north- 
westward, toward the axis of the chain ; and are broken off abruptly to 
the east, forming steep cliffy fronts toward the plains. The lower and 
outer ranges consist almost entirely of the variegated Series C., of which 
the red beds are often visible at a great distance. Many of the higher 
mountains are capped by the limestones of Series D., and where gaps in 
the eastern wall allow the inner ranges to be seen, they frequently show 
the upper fawn-coloured, and red beds, with gentle dips forming steep, 
but straight-edged ridges. Section 5 represents the geological structure, 
and general contour of the mountains to the north, as seen from a hill 
about six miles north of the entrance to the South Kootanie Pass. The 
most distant mountain of which the geological structure is indicated, was 
estimated to be about fifteen miles from the point of view. The more 
distant peaks shown on the horizon were but dimly visible, and must 
lie from fifty to one hundred miles northward. They appear to be of 
great height. 
142. The outlying or counterfort range, which is situated on the 
east side of Waterton Lake, has a breadth from west to east of seven 
miles. It may be designated the Wilson Range; that name having been _ 
applied to a part of it by Lieut. Blackiston. Its western side has been 
already partly described in connection with Waterton Lake. As viewed 
from the north, its fiont is chiefly composed of the rocks of Series C., of 
which subdivision 4, the red band, is conspicuous in many places. The 
central and higher parts of the range are of limestone belonging to 
Series D. Rocks differing from the rest, and apparently brought up by a 


be 
Se ee aes 
