THIKTY-OXE SUCCESSIVE SHORELINES. 22l 



topography of the udjoiuiug- couutiy^ show that no baixier of land so lugh 

 as tlie NiverviUe beach can have been removed there by erosion. The 

 original level of Lake Winnipeg, due to the height of the hind upon which 

 the Nelson River began to cut its channel in its present course, is doubtless 

 that of the well-detined beach observed by Hind between the mouths of 

 the Winnipeg and Red rivers, having "an elevation of 21 feet above the 

 present level of Lake Winnipeg."^ Traces of this shore-line will probably 

 be found at nearly the same height around the wlwle lake. 



SUCCESSIVE SHOltE-LINES OF EAKE AOASSIZ. 



In the southern part of the area of this glacial lake, within 75 miles 

 northward from its mouth at Lake Traverse, five principal beaches have 

 been observed, and in their descending order have been named, from 

 towns in Minnesota near which they are well exhibited, the Herman, Nor- 

 cross, Tintah, Campbell, and McCauleyville beaches. These shore-lines, 

 however, when traced farther north, are found to become double or mul- 

 tiple. The Herman beach in the vicinity of Maple Lake, Minnesota, is 

 divided into five beaches, four besides the highest having been formed 

 when the rise of the land, with the slight fall in the level of Lake Agassiz, 

 amounted, successively, to 8, 15, 30, and 45 feet on the east side of the lake 

 in that latitude. Still farther to the north, in Manitoba, we find seven 

 beaches corresponding to the single Herman beach at the southern outlet. 

 Li like manner, the Norcross and Tintah beaches are each represented at 

 the north by two, and the Campbell and McCauleyville beaches each by 

 three distinct shore-lines, separated by slight vertical intervals. The north- 

 ern part of the lake has thus no less than seventeen shore-lines, which were 

 successively formed from the highest to the lowest during the time of the 

 southward outflow through Lakes Traverse and Big- Stone and the Minne- 

 sota River to the Mississi})pi. 



After the lake obtained its earliest outlet to the northeast, sinking 

 below Lake Traverse, it formed fourteen shore-lines. The first tlu-ee of 



1 Chapter II, pp. 29 and 62. 



-Narrative of the Canadian Red River Exploring Expedition of 1857, and of the Assiuiboine and 

 Saskatchewan Exploring Expedition of 1858, Vol. I, p. 122. 



