10S J.B.TYRRELL — POST-TERTIARY DEPOSITS OF MANITOBA. 



I tliink we should be scarcely less than stolid — we of the United States — ■ 

 if we did cot strike hands with our brethren across the border over a 

 paper which brings into such beautiful consonance the phenomena on the 

 two sides of the international boundary. This paper Bets forth the phe- 

 nomena of the great plains on the north of the boundary in precisely the 

 same terms and under the same interpretations that we have been accustomed 

 to use on our side of the line. 



That which strikes me most, beyond this gratifying consonance, is the 

 remarkable extension of our knowledge which this paper and the two pre- 

 ceding papers relating to the northwestern part of our continent* give US 

 with respect to the delimitation of the ice sheets. The boundary line in the 

 western portion of the plains of the Dominion has been represented as ex- 

 tending nearly parallel with the foot of the Rocky Mountains down to our 

 boundary. It continues essentially parallel to the Rocky Mountains south- 

 ward in our territory to the vicinity of the Sun river, then curves easl and, 

 crossing the Missouri river, swings northward on the north Hank of the 

 Lightwood mountains, and thence northeast until it strikes the Missouri 

 again at the mouth of the Judith river; then, swinging back, it courses east 

 to the vicinity of Bismarck, where it once more turns south and keeps near 

 the course of the Missouri river until it strikes the Mississippi. So the de- 

 limitation in the western portion of the Dominion i- brought into perfect 

 harmony with that reported by the United Slates Geological Survey. 

 Taking this in connection with the facts given in the preceding paper, it is 

 scarcely a jump of interpretation to project this line along the foothills of 

 the Rocky Mountains north to the border observed in the Mackenzie basin, 

 and thence on to the delta of the Mackenzie, which practically carries the 

 delimitation to the A rctic sea. 



The limitation of this border to a line oil' the eastern base of the Rocky 

 Mountains is a remarkable facl when we consider the low condition of the 

 plain- easl of them: and the further fact that the glaciers of the Rocky 

 Mountain- had only a moderate extension is very remarkable. We must bear 



in mind thai these mountains are very high and very broad, and that there 



sweep over them breezes bearing an unusual load of moisture, much more 



than the winds that sweep over the Scandinavian mountains on the other 

 Bide of the Atlantic. Yet, notwithstanding all these highly favorable con- 

 ditions, they were not the source of any extensive glaciation, but, on the 

 contrary, the great glaciation came from the far lower heights of the eastern 

 part of the continent and spread across the vast Btretches of the great plains. 

 This, ii Beeme to me. is a fad of profound consequence, and its colossal 

 character ought not to be overlooked. 



i I Russell and R <• McConnell; the former printed among the memoirs (pp. 09 162), and 

 the latter in the proceedings, in this roluma. 



