404 THE ICE AGE IN NORTH AMERICA. 



Several successive levels of the ancient lake are recorded by 

 distinct and approximately parallel beaches, due to the gradual 

 lowering of the outlet by the erosion of the channel at Brown's 

 Valley, and these are named principally from stations on the 

 Breckenridge and Wahpeton line of the Great Northern 

 Railway, in their descending order, the Herman, Norcross, 

 Tintah, Campbell, and McCauleyville beaches, because they 

 pass through or near these stations and towns. 



The highest or Herman beach is traced in Minnesota from 

 the northern end of Lake Traverse eastward to Herman, and 

 thence northward, passing a few miles east of Barnesville, 

 through Muskoda, on the Northern Pacific Railway, and 

 around the west and north sides of Maple Lake, which lies 

 about twenty miles east — southeast of Crookston, beyond 

 which it goes eastward to the south side of Red and Rainy 

 lakes. In North Dakota the Herman shore lies about four 

 miles west of Wheatland, on the Northern Pacific Railway, and 

 the same distance west of Larimore, on the Pacific line of the 

 Great Northern Railway. On the international boundary, in 

 passing from North Dakota into Manitoba, this shore coin- 

 cides with the escarpment or front of the Pembina Mountain 

 plateau, and beyond passes northwest to Brandon on the 

 Assiniboine River, and thence northeast to the Riding 

 mountain. 



Leveling along this highest beach shows that Lake Agassiz, 

 in its earliest and highest stage, was nearly 200 feet deep above 

 Moorhead and Fargo ; a little more than 300 feet deep above 

 Grand Forks and Crookston; about 450 feet above Pembina, 

 St. Vincent, and Emerson; more than 500 feet above the 

 city of Winnipeg; and about 500 and 600 feet, respectively, 

 above Lakes Manitoba and Winnipeg. The length of Lake 

 Agassiz is estimated to have been nearly 700 miles, and its 

 area not less than 110,000 square miles, exceeding the com- 

 bined areas of the five great lakes tributary to the St. Lawrence. 



