LINE OF THE CANADIAN PACIFIC RAILWAY. 379 
pied a large area and probably overlapped large portions of the 
Huronian and Laurentian series. 
In approaching the Red River at Winnipeg, we pass over the 
eastern half of the great lacustrine deposit of the Red-River valley, 
extending, with a width of about 40 miles along that river, from the 
north to the south of the province of Manitoba, and constituting 
with its extension southward into the United States, what some of 
the geologists of that country have somewhat fancifully named the 
basin of the extinct ‘“ Lake Agassiz.” It presents a flat surface of 
the most typical prairie land, and consists of the finest possible silt 
with a covering of black vegetable soil. Very few boulders or 
stones appear on its surface, or in the cuttings made in it for drain- 
age; and the former are of small size, and may be accounted for by 
lacustrine ice-drift under climatal conditions similar to those now 
existing. 
West of the Red-River valley we enter on the higher prairie 
lands, extending westward about 700 miles to the foot of the 
Rocky Mountains. From the Red-River prairie, which is about 
800 feet above the level of the sea, they rise by two principal steps 
or escarpments, and intervening gradual slopes, to the higher plains 
at the base of the mountains, which in some places are 4200 feet 
above the level of the sea. The physical features of this region have 
been fully described by Dr. G. M. Dawson, in his paper on the 
“¢ Superficial Geology of the Central Region of North America,” in 
the Journal of this Society for November 1875, where also will be 
found reference to the work of earlier explorers in this field. I may 
add that the facts stated in that paper afford, in my judgment, the 
best existing key to the solution of the difficult questions of glacial 
geology in North America; and that, when applied to the regions 
south and east of the districts described, they are sufficient to enable 
any geologist to perceive the fallacy of the theories of continental 
land-ice applied by extreme glacialists to explain the drift pheno- 
mena of the middle and western parts of the United States. 
With the exception of a small area of Miocene Tertiary recently 
discovered*, the whole of this region is underlain by Cretaceous 
clays, sandstones and limestones, and by the shales and sandstones 
of Laramie or Lignitic Tertiary group, by some geologists regarded 
as late Cretaceous, by others as early Hocene (see Section, fig. 2, 
p- 882); but which the writer and other Canadian geologists have 
been disposed to regard as in great part a transition series, connect- 
ing the newer Cretaceous with the Eocene. Out of these formations 
the two prairie escarpments have been cut by water, the higher in a 
period of partial submergence before the glacial period, the lower at a 
later date by the waters of the extinct lake of the Red-River valley. 
The latest results as to the stratigraphical arrangement and 
relations of these deposits are stated in the following table, abridged, 
and slightly modified from the Reports of Dr. G. M. Dawson in the 
* At the Cypress Hills, Mr. R. G. McConnell, of the Canadian Survey, is stated 
to have found beds holding remains of Brontotheriwm, the first discovery of this 
kind hitherto recorded within the limits of Canada. 
Sar ee 
