428 THE GLACIAL LAKE AGASSIZ. 



McCaiileyville lieach appears to he ilO feet below the highest Campbell 

 beach at the northeni end of Duck Mountain. 



The McCauleyville shores are seldom marked by an eroded escarpment, 

 like that Avhich characterizes the principal Canipliell shore through consid- 

 eralile distances. Instead, they are traced by beach deposits, which are 

 generally well defined and often form a conspicuous ridge, .vying in size 

 with an}' other beach of this lake. 



EASTERN m'cAULEYVILLE SHORES IN MINNESOTA. 



(PLATES XXIII-XXVI.) 



Through a distance of 47 miles, from Lake TraA'erse north to the 

 soiitliern edge of Mitchell, a few miles east of McCauleyville, the border 

 of Lake Agassiz at its lowest level of southward outflow is mapjijcd on Pis. 

 XXIII and XXIV, the line l)eing drawn on the second of these plates in 

 accordance with the elevations determined at each quarter-section corner 

 on east-to-west section lines by the Red River Valley Drainage Commission 

 of Minnesota in 188(). It is not exactly horizontal, however, but has a 

 descent from the known level of the lake at White Rock, about 970 feet 

 above the sea, to the level indicated by the beaches between McCauleyville 

 and Barnesville, which is approximately 9G0 feet. Thus there appears to 

 have been a slight differential northward depression of this area, or else an 

 increase of the height of the land at Lake Traverse as compared with the 

 country northward, since Lake Agassiz ceased to outflow to the south. 

 These changes in relative elevations were opposite to those which were 

 intermittently in progress througliout all the explored portion of this glacial 

 lake during its whole history, giving to the shores their present nortliward 

 ascent. But the discordant movement reached no farther ufirth, for lieyond 

 Barnesville these shores on both sides of the lake rise continuously, though 

 very slowly, from 1 inch to 3 or 4 inches per mile, to the international 

 boundary. 



In the southwest part of Mitchell a broad, curved embankment, which 

 may be called a hook, extends from the south part of section 21, 2 miles 

 westward, and then about an equal distance southward, forming a })lateau- 

 like tract a quarter of a mile to nearly 1 mile wide. The narrowed southern 



