Rocky Mountains. 417 



we had deposited such plants as we wished to preserve, had 

 been placed for a pillow in the most sheltered part of the 

 tent, and covered with a coat, but these precautions and all 

 others we could adopt were unavailing, and the collection of 

 plants we had then made was lost. 



Wishing to deviate as little as possible from the course we 

 had assumed, and which we knew it was necessary to pur- 

 sue, if we would follow the most direct route to Council 

 Bluff, we descended on the 1 9th, into a broad and densely 

 wooded valley on our left. After crossing a part of this val- 

 ley, through heavy forests of ash, sycamore, and cotton-wood, 

 our progress was checked by a river of some magnitude^ and 

 so swollen and turbulent in consequence of the late rains, 

 that we thought it advisable not to attempt the passage. We 

 therefore relinquished our course, and being a long time de- 

 tained in painful and fatiguing exertions to extricate our- 

 selves from the forest, regained towards evening the open 

 plain and encamped. 



We had now ascended about eighty miles from the mouth 

 of Grand river. The country we had passed is fertile, and 

 presents such an intermixture of forests and grassy plains, as 

 is extremely pleasing to the eye. Towards the north the hills 

 become gradually more and more elevated. The discontinu- 

 ance of the horizontal limestone, the disclosure in the deep 

 vallies of the more ancient varieties of sandstone, and the 

 frequent occurrence in the soil of small rounded masses of 

 granite, gneiss, and other primitive rocks, indicates an ap- 

 proach towards the margin of the secondary basin. In the 

 deepest vallies about the sources of Grand river, we observe 

 a very hard semi -crystalline sandstone, in rather indistinct 

 strata, and containing apparently few remains either of plants 

 or animals. It is, in almost every respect, similar to that 

 sandstone, which, in the valley of Lake Champlain, rests along 

 the skirts of the granitic mountains of Ticonderoga, Crown 

 Point, and Westport, and supports there a small stratum of 



VOL. I. 53 



