

CRETACEOUS AND TERTIARY—WEST OF WOOD MOUNTAIN. 111 
anticlinal between the two localities. Our camp, situated a short way 
down the eastern slope of the White Mud Valley, and consequently 
somewhat below the general level of the prairie, was 445 feet above the 
Wood Mountain Astronomical Station, nineteen miles east, by compar- 
ison of seven barometric readings at each place. The base of the yellow 
sands being about 30 feet below the camp, is 409 feet above the 
Astronomical Station; and as the base of the same stratum (division 
y.) in the Bad Land section was found to be about 170 feet above the 
Astronomical Station, a difference of 239 feet between the same horizon 
in the Bad Lands and at White Mud River, would remain in favour of 
the latter. The distance being about thirty miles, gives an eastward slope 
of about eight feet in the mile. 
Cretaceous and Tertiary Rocks— Wood Mountain Settlement to the 
Crossing Place on White Mud River. 
272. The main trail going west from Wood Mountain settlement, 
passes for some distance along the northern edge of the water-shed 
plateau, and then going over it where it turns north-westward, crosses 
the valley of the White Mud River, sixteen miles north of the forty- 
ninth parallel, and twenty-three miles north-west of the exposures last 
described. Between Wood Mountain and the White Mud River the 
water-shed plateau is formed, as before, of the lower beds of the Lignite 
Tertiary, and projects like the prominent parts of a cameo, while the 
lower ground, and the deeper portions of the valleys of the streams, are 
formed of the underlying Cretaceous clays. On the trail, near Wood 
Mountain, small exposures of the Tertiary rocks frequently appear. 
About thirty-four miles west of that place, sections of characteristic 
sombre Cretaceous clay-shale occur, and a deep bay of these lower rocks, 
penetrates the edge of the Tertiary plateau from the north. in this 
vicinity. On ascending the plateau forming the west side of this bay, 
Lignite Tertiary rocks are again seen at intervals, to within about fifteen 
miles of White Mud River, when the road descends the western edge of 
the plateau, and again passes over the Crétaceous clays. 
273. A reference to the accompanying geological map will render 
the arrangement of the formations in this region clear. In the absence 
of other information for the district north-west of Wood Mountain, I would 
have followed Dr. Hector in provisionally indicating the border of the 
Tertiary as running from the Cypress to the Thunder Breeding Hills. 
The occurrence of a bay of Cretaceous rocks on the north side of the 

