6 Expedition to the 



blend was found more and more predominant, and so arranged 

 as to have, in the mass, a laminated appearance. The natural 

 fissures or cleavages between the laminae run nearly in a per- 

 pendicular direction, giving the rock the columnar structure 

 of trap, or greenstone. As they proceeded, a few interest- 

 ing insects and plants occurred to reward their labors. 

 But these impenetrable and naked rocks are the abodes of 

 few living beings either animal or vegetable. In the cre- 

 vices where a scanty soil has accumulated, is here and there 

 planted, a hardy evergreen, whose short and gnarled trunk, 

 and recurved inflexible branches, seem to proclaim the storms 

 it has withstood, and the centuries during which it has ve- 

 getated. 



The design of the party had been to cross the first r^nge 

 of the mountains and gain the valley of the Platte beyond, 

 but this they found themselves unable to accomplish. After 

 climbing successively to the summit of several ridges, whieh 

 they had supposed to be the top of the mountain, they still 

 found others beyond higher and more rugged. They therefore 

 relinquished the intention of crossing, and began to look for 

 the best way to descend to the bed of the river, which lay on 

 their left hand. Here they halted to rest fur a few moments, 

 and exposed a thermometer in the shade of a large rock. 

 The mercury fell to 72^; in camp, at the same hour, it stood 

 at 86°. They were so much elevated above the river, that 

 although they could sec it plainly, it appeared like a small 

 brook of two or ihrve yards in width, white with foam and 

 spray caused by the impetuosity of its current and the rough- 

 ness of its channel. They could distinguish two principal 

 branches of the Platte, one coming from the northwest, the 

 othrr from ;he south. A little below the confluence of these 

 brarchts iht liver turns abruptly to S. E., bursting through a 

 ch:ism in a v:Ast ni'iral pn cipice of naked colun.nar rocks. 



About noon the detichment tommencid their descent, 

 which cost them no less exertion than their ascent in the 



