

GENERAL PHYSICAL GBOGRAPHY. 5 
- indicated, and to the west by the Missouri Coteau, or edge of the third 
prairie level. It hasa width on the forty-ninth parallel of two hundred and 
fifty miles, and on the fifty-fourth of probably about two hundred, though —, 
it cannot there be so strictly defined. Its total area is about 105,000 
square miles, and includes the whole eastern portion of the great plains 
:. properly so-called, with an approximate area of 71,300 square miles. 
, These occupy its southern and western portions, and are continuous west- 
. ward with those of the third prairie steppe. To the south, the boundaries 
of this region appear to become more indefinite, and in the southern part of 
Dakota, the three primary levels of the country so well marked north of 
the Line, are probably scarcely separable. The rivers have acted on this 
region for a much longer time than on the last, and are now found flowing 
with uniform currents in wide ditch-like vallies excavated in the soft 
material of the plains, and often depressed from one-hundred to three- 
hundred feet below the general surface. In these, the comparatively 
insignificant streams wander from side to side, in tortuous channels, 
which they only leave in times of flood. The surface of this prairie 
steppe is also more diversified than the last, being broken into gentle 
swells and undulations, partly, no doubt, by the action of denudation, and 
partly also as will appear, from the original unequal deposition by currents 
and ice, of the drift material which here constitutes the superficial form- 
ation. The average altitude of this region may be taken at 1,600 feet, 
and the character of its soil and its adaptability for agriculture, differ 
much in its different portions. | 
9. The third or highest prairie steppe, may be said to have a 
general normal altitude of about 3,000 feet, though its eastern edge is 
sometimes little over 2,000 feet, and it attains an elevation of 4,200 feet 
at the foot of the Rocky Mountains. Its area, including the high land 
lying along the base of the mountains, is about 134,400 square miles, and 
of this by far the greater part, or about 114,000 square miles, appears to 
_be almost entirely devoid of forest; the wooded region being confined toa 
small area of its northern extension near the North Saskatchewan River 
and its tributaries. Its breadth on the forty-ninth parallel is four hundred 
and sixty-five miles, and its eastern boundary is well marked, being the 
broken hilly country known as the Coteau de Missouri or Great Coteau, 
which crosses the Boundary near the 104th meridian, and thence runs 
north-westward nearly to the Elbow of the South Saskatchewan. It is 
then—according to Palliser—continued to the north by a range of high 
lands, of which the Eagle Hills west of Fort Carleton constitute a part. 


