446 THE GLACIAL LAKE AGASSIZ. 



stage of the lake to which it belongs, mapped on PI. XXXV, is the only 

 one of the three which is generally marked plainly by a shore-line in 

 Minnesota and North Dakota. 



With the description of the Blanchard beaches in Miimesota, closely 

 associated portions of the next lower or Hillsboro beach are also described 

 near Grlyndon and from 5 to 15 miles north of Crookston. 



The principal and lowest Blanchard shore, having a height of about 

 925 feet, crosses the Red River close to Wolverton station, on the Great 

 Northern Railway, almost exactly halfway between Wahpeton and Moor- 

 head. Passing northward into Clay County, tliis shore is marked by a belt 

 of gravel and sand thinly spread upon a broad, gently rising swell of till 

 which is known as Pleasant Ridge, traceable in a nearly due-north course 

 about 15 miles thi-ough the west parts of Alliance, Elmwood, and Glyndon 

 townships. The South Branch of the Buffalo River flows nearly parallel 

 with it, at a distance of a half mile to 1 mile farther east. Shore ciurents, 

 carrying southward much of the gravel and sand derived from the shallow 

 wave erosion of the till along the northern part of the ridge, deposited it 

 in a rounded and partly almost flat tract a half mile to tliree-fourths of 

 a mile wide in the northwest part of Alliance, having a height of 925 to 

 935 feet above the sea. Through Elmwood and Glyndon the beach depos- 

 its are narrow and scanty, lying on the western slope of Pleasant Ridge 

 and along its crest. At Sabiu they are bounded on the west by a typical 

 beach slope, with its top at 930 feet, from which there is a descent of about 

 10 feet westward within 40 or 50 rods. In Glyndon the crest of the ridge 

 is in part a sand and gravel beach, extending north tlu'ough the centers of 

 sections 32, 29, 20, and 17, declining slowly in height from 927 feet at the 

 south to 922 feet at the north. Where the contiimation of this line crosses 

 the Northern Pacific Railroad the sm-face was a few feet below the Blanch- 

 ard level of Lake Agassiz, and no beach was accumulated. 



A few miles south of this railroad a scanty lower beach deposit was 

 noted in sections 30 and 19, Glyndon, three-fourths of a mile west of the 

 preceding, with its crest at 919 to 021 feet. This represents the Hillsboro 

 stage of the lake, and, indeed, the formation of the main beach in this 

 township, as just described, seems referable to the time of recession of the 

 lake between the lower Blanchard and Hillsboro stages. 



