212 B. N. A. BOUNDARY COMMISSION. 
480. The boulders observed on the road from the North-west Angle 
to Winnipeg, were nearly all of the usual Laurentian materials. On the 
west side of the watershed, some boulders of limestone appear, and much 
of the gravel seen in banks is also of this material. It would segm that 
the edge of the limestone of the Red River basin cannot here be far 
below the surface. | 
Drift Plateau of Eastern Manitoba and Northern Minnesota. 
481. From the above descriptions of the superficial deposits of the 
Lake of the Woods, it will be seen that those answering to the boulder 
clay, properly so called, comparatively seldom appear, being covered for 
the most part by more modern accumulations, either those of a later period 
of the drift, or those produced by the lake itself, while standing at a 
higher level than at present. Southward and westward, from the Lake 
of the Woods, the country is studded with innumerable small lakes and 
swamps, which have formerly been more important, and the compar- 
atively modern deposits of which, cover the more ancient glacial debris. 
The northern part of Minnesota, and the country immediately west of 
Lake of the Woods, may be represented as a great high-level plateau of 
drift materials, banked up on the sloping spurs of the rocky Laurentian 
region to the north, and covering, often to a very great depth, its old 
irregularities. It may also be considered broadly as forming the eastern 
representative of the second prairie steppe, as it stands at about the level 
which that plateau would have, were its gradual eastern slope continued 
thus far. 
482. The surface of this plateau, though frequently irregular in 
detail, and covered with banks and ridges of sand and gravel of the 
’ 
nature of “ Kames” and “ Eskers,” is, on the whole, remarkably uniform. 
A section along the forty-ninth parallel, from the ridge bounding the 
alluvial valley of the Red River to the east, to the Lake of the Woods—a 
distance of 77 miles—shows slopes which are so extremely gentle, as to 
be almost imperceptible; the total general westward fall of the surface in 
that distance, being only about 90 feet. An examination of the profile of 
the Northern Pacific Railway, from Duluth, to Morehead on the Red 
River, 160 miles further south,* shows the nature of the southern exten- | 
sion of this plateau, which is here the birth-place of tributaries of the Red 
River, the Mississippi and the St. Lawrence. . Rising pretty rapidly from 


* See First Annual Report, Geol. Surv, Minn,, 1873. Prof. N. H. Winchell. 

