56 THE GLACIAL LAKE AGASSIZ. 



quite to the high- water line thus noted have been rare, oecun-ing in 1826, 

 1852, 1860, 1861, and 1882. They are caused in the spring by the melting 

 of unusual supplies of snow and by accompanying heavy rains, and often 

 are increased by gorges of ice, which is usually broken up along the 

 southern upper portion of the river earlier than along its lower course. 

 These floods attain a height only a few feet below the level of the adjoining 

 prau-ie where that is highest, and along the greater part of the distance 

 between Grand Forks and Lower Fort Garry the banks are ovei-flowed 

 and the flat land on each side of the river to a distance of 2 to 4 or 5 miles 

 from it is covered with water 1 to 5 feet or more in depth. 



The noteworthy tributaiies of the Red River on its east side, in their 

 order from south to north, are the Buffalo, Wild Rice, Marsh, Sand Hill, 

 Red Lake, Snake, and Tamarack rivers, the stream named Two Rivers for 

 its two branches which unite 3 miles above its mouth, and Joe, Roseau, 

 and Rat rivers; and on the west, the Bois des Sioux, Wild Rice, Sheyenne, 

 Elm, Goose, Turtle, Forest, Park, Pembina, Marais, Scratcliing or Boyue, 

 La Salle, and Assiuiboine rivers. Excepting the Red Lake River, ah-eady 

 described, and the Shej^enne, Pembina, and Assiniboine rivers, all these are 

 small, the farthest portions of their areas of ch-ainage being 40 to 75 miles 

 from the Red River. In summer droughts several of them, including the 

 Bois des Sioux, are dried up along the greater part of their course, contain- 

 ing only here and there pools in the deeper hollows of the channel. 



Sheyenne River. — The Sheyenne, having its sources near the great 

 southeastern bend of the Souris or IVIouse River, in Korth Dakota, first 

 flows to the east nearly 100 miles, passing 10 miles south of Devils Lake; 

 next it flows south about 100 miles, to where it enters the area of Lake 

 Agassiz; and thence its course is eastward and northward, uniting with the 

 Red River 10 miles north of Fargo and Moorhead. AVhere it is crossed 

 by the Jamestown and Northern Railroad, south of the west end of Devils 

 Lake, its elevation is 1,410 feet above the sea. Thence it falls to 1,064 

 feet at Lisljon, and 857 feet at its mouth Along its eastward and south- 

 ward course it flows through an undulating or rolling and occasionally hilly 

 region, in which its valley is eroded 100 to 200 feet deep. Within the area 

 of Lake Agassiz it has cut 50 to 75 feet into its delta, and beyond occupies 



