8 THE GLACIAL LAKE AGASSIZ. 



miles. A preliminary report of part of these observations was published 

 in 1887.^ 



B}* cooperation of the geological surveys of the United States and 

 Canada, a portion of my field work in 1887 was devoted to the examination 

 of the northward extension of the beaches of Lake Agassiz in Manitoba. 

 Traveling T\'itli horse and wagon, and assisted by Mr. Young, a somewhat 

 detailed exploration of this lacustrine area was continued about a hundred 

 miles north from the international boundary, the most northern points 

 reached being Shoal Lake, between Lakes Winnipeg and Manitolia, and 

 Orange Ridge post-office, near the southeast end of Riding Moitntain. The 

 mainly wooded character of the country farther north makes continuous 

 leveling and tracing the beaches of this lake imjijracticable; and the same 

 condition limited my examination on the east to a naiTow belt adjoining 

 the Red River. The western border of this portion of Lake Agassiz is 

 formed bv the Pembina Mountain, the Tiger Hills, the Brandon Hills, and 

 Riding Mountain; and the mouth of the Assiniboine was at Brandon during 

 the highest stage of the lake. In this direction my observations were 

 extended west of the shore-line of Lake Agassiz to include the vicinity of 

 the Assiniboine and the Canadian Pacific Railway to Griswold, the course 

 of the Souris River below Plum Creek, Langs Valley, a glacial Avater- 

 nn-se extending from the elbow of the Souris southeast to Pelican Lake 

 and the Pembina River, and the lower course of that river, bv which a 

 large delta was deposited in the west margin of Lake Agassiz a few miles 

 south of the international boundary. The breadth of the country thus 

 ti-aversed from east to west is about 150 miles. A report of this work has 

 been published by the Canadian Geological Survey." 



For all these surveys in the United States and ]\Ianitoba profiles of 

 the numerous railway lines crossing this district supplied reliable elevations 

 above the sea-level at their stations; and in many instances they also show 

 distinctly their intersections of the beaches of this lake. These elevations 

 were taken as the data and reference points of my leveling, w^hich was 



'U. S. Geol. Survey Bulletiu, No. 39. The Upper Beaches and Deltas of the Glacial Lake Agassiz. 

 Pp. 84, with map 



-Geol. and Xat. Hist. Survey of Canada, Annual Ee])ort, new series. Vol. IV, for 1888-89, Part E, 

 Report of Exploration of the Glacial Lake Agassiz in Manitoba, pp. 156, with two maps and a plate 

 of sections. 



