396 THE GLACIAL LAKE AGASSIZ. 



ascent of these beaches in the 70 mik^s northwnnl from the httitude of 

 Gladstone and Neepawa to the Valley River is aliout 75 feet, or very 

 closely 1 foot per mile, being slightly more than from the international 

 bomidary to Neepawa. 



On Shanty Creek, 20 miles farther north, these beaches, according to 

 Mr. Tyrrell, are 1,365 and 1,319 feet above the sea, showing the very 

 remarkable northward ascents, respectively, of 85 and 59 feet, or about 4 

 and 3 feet per mile. 



Along the next 25 miles north to the Pine River, where, according to 

 my correlation, the upper Norcross beach has a height of 1,440 feet,' its 

 ascent continues at the rate of 3 feet per mile. This is tlie highest altitude 

 at which any beach of Lake Agassiz has been recorded. Its latituile is 

 51° 52" north, being 200 miles north of the international boundary. It is 

 422 miles north of Lake Traverse and the mouth of Lake Agassiz, in which 

 distance this shore has a total ascent of about 400 feet. 



The significance of the more rapid northward rise of these shore-lines 

 and others below them in the district of Riding and Duck mountains than 

 aloug all the portion of the lake border explored by me farther south has 

 been partly discussed in Chapter V, on the history of this lake, and will be 

 again considered in Chapter IX, on the changes in the levels of its beaches. 



BEACHES OF THE TINTAH STAGES. 



EASTERN TINTAH SHORES FROM LAKE TRAVERSE TO TINTAH AND NORTHWARD 



IN MINNESOTA. 



(PLATES XXIII-XXVI.) 



The plateau, 3 to 4 miles across, which formed an island in Lake Agas- 

 siz, situated between Wheaton and the Mustinka River, on the southeast, 

 and the Bois des Sioux River and White Rock station, on the n(»i-thwest, 

 rising to an altitude of 1,040 to 1,055 feet, is encircled by the Herman, 

 Norcross, and Tintah shore-lines. This high tract has a base of till, but 

 the plain forming its top consists, to a depth of 10 to 20 feet or more, of 



'Stated to be 1,460 feet by Mr. Tyrrell, in the Bulletin of tbe Geological Society of America, 

 Vol. I, 1890, p. 406; but later published by him as 1,440 feet in the Am. Geologist, Vol. VIII, p. 23, 

 July, 1891. 



