546 THE GEOLOGY OF MINNESOTA. 



[Boulders. 



carpment that passes north and south. They evidently once constituted 

 one immense boulder and have become six from the falling apart, under 

 the influence of frost, of the granite along its natural seams or joints. 

 Such a separation of large boulders sometimes is seen on the prairies in 

 Minnesota under circumstances which demonstrate their former entirety. 

 The largest three pieces, each about twenty feet long and twelve feet high, 

 are the Three Maidens, so called. Another piece is about twenty feet long 

 and eight feet high. Two other pieces, nine and twelve feet long, are four 

 or five feet high. There is also a seventh fragment about five feet in 

 length. Together they must have constituted, as remarked by Mr. Up- 

 ham, the largest ice-transported block known in Minnesota, making a 

 mass from fifty to sixty feet in diameter. The pieces are all alike, and no 

 other boulders of any kind are seen in the vicinity. They consist of red, 

 coarse-grained granite, similar to that seen in outcrop near New Ulm, a 

 short distance west of the outcrop of conglomerate on the north side of 

 the river. Other large boulders of red granite are found in Eock county, 

 and, taken in connection with their size, they all indicate the close prox- 

 imity of their source. It is probable that the rock that underlies the Pots- 

 dam in these counties consists of this red granite.* 



' FIG. 42. THE THREE MAIDENS. 



See Catlin's speculations, page 64; also compare the report on Nicollet county. The name three maidens is applied 

 to these boulders from the tradition that after the destruction of all the tribes in war, the present Indians sprang; from 

 three maidens who fled to these rocks for refuge. 



