404 THE GLACIAL LAKE AGASSIZ. 



upper limit of the steeper eroded belt is at 1,0G2 to 1,070 feet, being about 

 20 feet above its base. Beyond this township, northward to the Pem- 

 bina delta, the courses of the Tiutah shores, tlu)Ugh not exactly traced, are 

 known very nearly from the rate of eastward descent of the land and from 

 the mapped course of the next succeeding Campbell beach. At one locality 

 a, Tintah beach ridge was noted, near the middle of the line between sec- 

 tions 19 and 18, Kensington, about 2 miles northwest from the town of Park 

 River; but the next two miles or more northward have a rather irregularly 

 rolling surface, with no definite beach observable. 



The Tintah shore* are only a short distance below those of the Nor- 

 cross stages on the flanks of the Pembina delta and on the lower part of 

 the Pembina Mountain escarpment for several miles thence northward. 



WESTERN TINTAH SHORES IN MANITOBA. 



(PLATES XXX-XXXllI.) 



In proceeding northward from the international boundary, the Tintah 

 beaches were first observed near the line between townships 1 and 2, range 

 5, lying on a terrace which forms the lower part of the Pembina Mountain. 

 On the boundary this terrace is about three-fourths of a mile wide, its 

 eastern margin being an escarpment that rises from 1,040 to 1,090 or 1,095 

 feet; and from its verge it gradually rises 25 to 35 feet in its width, so that 

 its western limit at the base of the main escarpment has a height of 1,120 

 to 1,125 feet. Its surface is till with plentiful bowlders, nearly all Archean, 

 up to 5 feet 111 diameter, mostl}^ embedded or only projecting a foot or less; 

 but the slope on its east side consists of weathering and pulverized Cretace- 

 ous shale, which is thus shown to form the principal mass of the terrace, 

 beneath a thin mantle of till. In the distance of 6 miles northward across 

 township 1 this terrace widens to 2 miles, and its eastern verge sinks to 

 1,055 feet; but it is bordered by only a slight escarpment, about 15 feet 

 high, the base of which is thus at the same level as on the international 

 boundary. In its width of 2 miles it there rises about 90 feet to the base 

 of the mountain escarpment, at 1,140 to 1,150 feet. A quarter to a third of 

 a mile east of this escarpment a line of erosion rises from 1,110 to 1,125 

 feet, approximately, marking the upper Tintah shore. In the southeast 



