74 THE GLACIAL LAKE AGASSIZ. 



out." At Point Wilkins, on the west side of Dawson Bay, the Dakota 

 sandstone, forming the base of the Cretaceous series which underlies the 

 drift farther west, was seen lying on the eroded surface of the horizontally 

 stratified Devonian limestones. 



Along the Saskatchewan, Silurian, and Devonian strata, mainly hme- 

 stones, reach from Lake Winnipeg to Fort h la C'orne, about 12 miles below 

 the junction of the south and north branches of this river. Thence to the 

 nortliwest and north, a belt of these rocks, in large part almost horizontally 

 bedded, skirts the west side of the Archean area to the Arctic Sea. 



SECTIONS OF ARTESIAN WELI^S IN PALEOZOIC STKATA. 



Four deep borings for artesian water reveal the order and thickness of 

 the several members of the Paleozoic group forming the floor of the Red 

 River Valley beneath the drift in the vicinity of the international boundary. 

 These wells, in their order from east to west, are situated at Humboldt in 

 Minnesota, Grafton in North Dakota, and Rosenfeld and Mordeu in Mani- 

 toba. Notes of their sections are presented in the following pages, and 

 their stratigraphic relationship is shown in PI. XV. 



The well at Morden penetrates only to the base of the Devonian or 

 top of the Upper Silurian. The Rosenfeld well, entering the bed-rocks at 

 a horizon near that .where the Morden well left off, gives apparently a 

 complete section of the Upper and Lower Silurian series, passing at its 

 bottom through the Lower Magnesian formation, which is the base of the 

 latter, lying next below the St. Peter sandstone. Another section of the 

 Lower Silurian formations, from the Galena and Trenton to the Lower 

 Magnesian, is supplied by the well at Humboldt; and the Grafton section, 

 besides duplicating that of Humboldt, passes nearly 300 feet beyond in 

 probably Upper Cambrian strata, referable to tlie Jordan, St. Lawrence, 

 and Dresbach foniiations of the St. Croix series. 



WELL AT HUMBOLDT, MINN. 



Humboldt is a station of the Great Northern Railway, about 7 miles 

 southeast of St. Vincent, at the farm of Mr. D. H. Valentine, on which this 

 well is situated. It is on the flat plain of the Red River Valley, 6 miles 



