HISTORICAL SKETCH. 41 



1823, Keating.] 



THE COTEAU DBS PRAIRIES. 



Although the party did not visit the Coteau des Prairies, Prof. Keating 

 makes 'some interesting notes on its character and direction, which may 

 be summarized briefly thus: Its hight above the St. Peter, at Big Stone 

 lake, is thought to be not short of 1,000 feet. According to the best infor- 

 mation he could obtain, " this ridge commences about the 49th parallel of 

 north latitude, and between the 98th and 99th degrees of west longitude 

 from Greenwich. It proceeds in a direction nearly south south-east, passes 

 east of the group of small lakes called Devil's lake, divides the tributaries 

 of the St. Peter from those of the Missouri, and extends southerly as far 

 as the head of the Blue Earth, where it gradually widens and sinks to the 

 level of the surrounding country." He mentions a second ridge or coteau, 

 commencing at the southern bend of Mouse river, running in a direction 

 nearly parallel with that of the other, from near the 48th parallel to beyond 

 the 44th parallel, in a southeasterly course for about eighty miles, when it 

 turns to the west of south and likewise sinks and disappears, the valley of 

 the James river being between the two ridges. Mr. Keating was informed 

 that no rocks can be seen composing the Coteau, but that it presents a 

 uniformly smooth, prairie-like appearance, the ascent being gradual aud 

 easy on both sides. He however was of the opinion that it is formed 

 by an elevation of the granite rocks above their usual level, although, 

 perhaps, covered as with a mantle by the secondary and alluvial rocks, 

 predicting that if its whole course were to be followed "from the Assini- 

 boine to the Blue Earth " the geologist would be rewarded by the discovery 

 of the "granite formations, if not along the whole of its crest, at least in 

 some of the ravines which head near it." Above Big Stone lake the St. Peter 

 is said to divide itself into two branches, coming from the west, heading in 

 the Coteau, one of which comes from west by south for abont twelve miles. 

 The northern, and larger branch, has its source in Polecat lake, about 

 twenty-four miles distant, west by north, from the point where they join 

 Big Stone lake. That lake is one and a half miles long, and half a mile wide, 

 and frequently dry. There are many indications in the narrative that 

 this hasty reconnoissance of the Minnesota valley was not satisfactory to 

 Prof. Keating. 



