388 THE GLACIAL LAKE AGASSIZ. 



district of tlie Beltrami Island, they curve east-soutlieasterly to the valley 

 of the Rainy River and the vicinity of Rainy Lake, and thence sweep 

 back to the northwest and north across the hilly Archean region east of the 

 Lake of the Woods. 



THKOUGH NORTH DAKOTA, FROM LAKE TRAVERSE TO THE INTERNATIONAL 



BOUNDARY. 



(PLATES XXIII AN1> XXVII-XXX.) 



On and near the line between South and North Dakota, at a distance 

 of 3 to 7 miles west of White Rock and the Bois des Sioux, the Norcross 

 stages of Lake Agassiz formed no less than four separate and parallel beach 

 ridges of gravel and sand, 3 to 8 feet high, lying on a surface of till. In 

 section 1, township 128, range 48, South Dakota, where these small ridges 

 run to the northwest and north-northwest, the elevations of their crests in 

 order from west to east are, first, 1,045 to 1,048 feet above the sea; second, 

 1,043 to 1,045 feet; third, 1,033 feet; and, fourth, 1,030 feet. The highest 

 beach of this series passes about a half mile west of Mr. L. H. Foote's 

 house, which is in the southeast corner of this section; the second runs 

 about 40 rods west of this house ; and the third and fourth lie about a third 

 of a inile and a half mile east of it, passing thence northward tlu'ough the 

 northeast corner of this section 1. Following these beach ridges in their 

 ciu-ving course to the northwest and west-northwest into section 28, town- 

 ship 129, range 48, the higher two are found to rise to 1,050 feet, and the 

 height of each of the lower two is increased by 10 feet. The continuations 

 of these shore-lines northwestward to the east side of the Lightnings Nest 

 and to the delta of the Sheyenne River have not been exactly traced. No 

 other tract of the Norcross shore of this southern part of Lake Agassiz, so 

 far as observed by this smwey, is thus marked by several beach ridges. 

 The multiplication of their number here, which elsewhere is commonly 

 single along all the southern part of the lake, probably was due to a slight 

 intermittent elevation of this tract while the adjacent country was at rest, 

 until an uplift of the whole area about Lake Traverse led to the formation 

 of the Tintah beaches, the next lower in the descending series. 



