OJATA BEACHES IN MINNESOTA. 459 



BEACHES OF THE OJATA STAGES. 



The upper Ojata shore-line has au elevation between 870 and 875 feet 

 above the sea where it crosses the Red River near Perley, Minn., and 

 Noble, N. Dak., about 20 miles north of Moorhead and Fargo. Its course 

 in Minnesota has been mapped approximately for 25 miles thi-oug-h Norman 

 C<iunty, lying- from 2 to 6 miles east of the river, according to the contour 

 shown by the Drainage Survey ; but it is not known how much of the shore 

 is there mai'ked by any beach ridge or line of erosion. Probably a con- 

 siderable part is thus definitely traceable, especially northward, where the 

 surface is till. 



After curving eastward, near the boundary between Norman and Polk 

 counties, to a distance of 10 miles from the Red River, this shore turns to 

 the north and north-northwest, crossing the east part of the great marsh 

 which is formed by the waters of the Sand Hill River and of many springs. 

 In the northeastern edge of this marsh it bears a consjncuous beach ridge, 

 which runs from near the center of section 10, township 147, range 47, 6 

 miles to the north side of section 18, Hammond. The crest of the dry 

 ridge of sand and gravel is 873 to 878 feet above the sea, and the surface 

 of the marsh adjoining it is about 3 feet lower on the east and 5 feet lower 

 on tlie west. 



About 2 miles northwest from Crookston a large beach deposit of 

 gravel and sand on this shore-line is crossed by the Gi'eat Northern 

 Railway in sections 24 and 23, Lowell, and has been much excavated for 

 railwaj- ballast. The elevation of its crest is 880 to 882 feet, and its thick- 

 ness is 3 to 5 feet, lying on till. The pebbles of the gravel seldom exceed 

 3 inches in diameter, and are mostly magnesian limestone, similar to the 

 strata which outcrop near Winnipeg. 



The Drainage Survey shows that the farther course of this shore is 

 nearly due north for the next 40 miles, passing about 2 miles west of 

 Shu-ley, a mile west of Euclid, IJ miles east of Angus, about 3 miles ea.st 

 of Warren, and 5 miles east of Argyle. Through the greater part of this 

 extent it lies on or near the Avestem edge of the till, which is succeeded 

 toward the Red River by lacustrine and alluvial silt. In a few places the 



