SOURCE OF ST. PETEr's RIVER. 351 



of the largest probably does not exceed one quarter of 

 a mile; they rise to about thirty-five feet above the level 

 of the water. Their form is irregular ; their aspect rug- 

 ged and barren compared with the fertile bottom of the 

 valley ; their general colour is of a dark gray ; they appear 

 to be the summit or crest of primitive rocks which under- 

 lay this valley, and which protrude at this place through 

 the superior strata. As the adjoining prairies are elevated 

 about fifty feet above the level of the river, these primi- 

 tive rocks are observable only in the valley ; they doubt- 

 less constituted at one time a continuous ridge, but have 

 been divided into insulated masses by the corroding action 

 of the stream, whose very circuitous bed winds between 

 them. They extend upon a distance of about six miles in 

 the direction of the valley. After having examined al- 

 most every one of these masses, we feel unwilling to de- 

 cide with certainty, which of the primitive combinations 

 predominates ; for the passage of the one into the other is 

 more constant and more sudden than in any other primi- 

 tive formation that has ever come under our notice. In- 

 deed we know of none with which to compare it, except 

 it be that which we observed at a subsequent period of the 

 expedition, between Lake Winnepeek and the Lake of the 

 Woods ; but even there the features were somewhat dif- 

 ferent, for they were on a larger scale. The passages, which 

 we there observed, were sometimes to be traced only upon 

 large masses ; whereas on the St. Peter, it would have been 

 difficult to break off a fragment of a cubic foot in size pre- 

 senting an uniform character of composition. It is, how- 

 ever, probable, as far as our observations extended, that gra- 

 nite is the predominating rock. These masses bear very evi- 

 dent signs of a crystalline origin, but the process must have 

 been a confused one. Tourmaline is found disseminated 



