2 Expedition to the 



It is difficult, when contemplating the present appearance 

 and situation ol these rocks, to prevent the imagination from 

 wandering back to that remote unascertained period, when 

 the billows of the primeval ocean lashed the base of the 

 Rocky Mountains, and deposited, during a succession of 

 ages, that vast accumulation of rounded fragments of rocks 

 alternating with beds of animal remains, which now extend 

 without interruption from the base of this range to the sum- 

 mits of the AUeghanies; and endeavouring to form some con- 

 ception of that subsequent catastrophe which has so changed 

 the relative elevation of the two great formations that the 

 margin of the secondary has been broken off and thrown in- 

 to an inclined or vertical position. 



The valley between this parapet of sand-rock and the first 

 granitic ridge is near a mile wide. It is ornamented with 

 numerous isolated columnar rocks, often of a snowy white- 

 ness, standing like pyramids and obelisks, interspersed among 

 mounds and hillocks, which seem to have resulted from the 

 disintegration of similar masses. 



The range of sandstone appears to have been originally of 

 uniform elevation and uninterrupted continuity, stretching 

 along the base of the mountains from north to south, but it 

 has been divided transversely by the bed of the Platte, and 

 all the larger rivers in their descent to the plains. 



From our camp, we had expected to be able to ascend 

 the most distant sumniits then in sight, and return the same 

 evening, but night overtook us and we found ourselves scarce- 

 ly arrived at the base of the mountain. The lowest part of the 

 sandstone stratum, exposed at the western declivities of the 

 hills, and in the points nearest the granite, contains extensive 

 beds of coarse conglomerate or pudding-stone, often of a 

 reddish colour. The more compact parts of the rock pre- 

 sent remains of terebraiulge and other submarine animals. 

 Among these, few are entire or in good preservation. We 

 observed here, several singular, scorpion-like animals, inha- 



