
ROCKY MOUNTAINS—BOUNDARY MOUNTAIN. 65 

station of the old North-west Boundary Commission, is situated at the 
head of the valley just described. It has an elevation of about 6,000 feet 
above the sea, and is a sheltered hollow characterized by thick spruce 
woods of fine growth. The Boundary Cairn is placed on the watershed 
about a mile from the camp, and though built thirteen years ago was 
found in perfect preservation. It is important as marking not only the 
forty-ninth parallel or boundary between British North America and the 
United States, but as lying at the adjacent angles of British Columbia 
and the as yet unorganized North-west Territory. 
138. Near Camp Akamina the rocks are red sandstones, but are not 
_ well shown or regular in position. In a mountain-side between the camp 
and the Boundary Monument, however, a very good section is exposed ; 
and here the structure of series F. and G. of the general section was 
best seen, and over six hundred feet in thickness examined. The section 
may be taken as embracing the lower beds of Series G., and the whole of 
Series F. The highest beds examined consist almost entirely of flaggy 
dull-red compact sandstones, which are frequently ripple-marked. Above 
them about two hundred feet of similar reddish beds was visible in distant 
hill-sides, and these again were overlaid by the upper fawn-coloured 
Series H. In descending, these begin to alternate with beds of grey and 
fawn-coloured sandstones, the latter magnesian, and whitish on fresh frac- 
ture. Lower in the section, while red and reddish-purple sandstones 
still continue, whitish and fawn-coloured limestones,—frequently concre- 
tionary,—are intercalated, and become thicker and more frequent toward 
the base. The lowest rock seen in Series F. is a dark purplish sandstone, 
and not far below it is the trap designated in the general section by the 
letter E. Many of the sedimentary beds throughout the entire section 
are ripple-marked, and rain-pitting and sun-cracks are not infrequent. 
At several different levels, too, the surfaces of sandstone beds show 
impressions caused by salt crystals, subsequently dissolved out. Some 
of these are as much as half an inch in diameter, and exhibit distinctly 
the peculiar hopper-shaped forms characteristic of sodic chloride. The 
conditions of formation indicated by the rocks are those of a shallow, 
land-locked, salt lagoon or lake ; which was, perhaps, sometimes in com- 
munication with the open sea. No traces of fossils could be found. 
139. The division made between Series F. and G., and that between G. | 
and H., are probably not of great importance. No unconformity obtains, 
and the same conditions seem to have prevailed throughout ; the deposi- 
tion of reddish sandstone, alternating with that of pale dolomitic sand- 
5D 

