6 BOTANY. 



Valley, it is much lower, about 7,500 feet above the sea. Here, however, 

 the lowland coniferous growth is made up entirely of Pinus edulis, Engelm , 

 and Juniperus Virginiana. 



It seems that where the hills begin fairly, they have been seized at 

 once by some tree. Cottonwood trees appear both on the plains and mount- 

 ains, where the supply of water is constant or nearly so. The Conifers 

 above named are constantly found associated on the foothills at least as far 

 north as Canon City. They do not fairly enter South Park. The line 

 along the Valley of the Arkansas is sharply drawn. The ridge dividing it 

 from Trout Creek is covered on its western slope by these trees, while to 

 the east of it they hardly appear. 



From some facts observed I am led to think that at no distant past the 

 growth of Coniferce extended much lower into the Park than it now does. 

 I have seen the decaying remains almost down to the Platte. The knots, 

 which, as is well known, last a long time, were found scattered here and 

 there frequently in the lower portions of the open ground. An occasional 

 isolated clump of these trees still survives, far removed from their associates 

 on the mountain-sides ; and at times one may observe that the prolonga- 

 tions of pine-woods, which extend out into the Park, become less and less 

 dense, until finally only a single tree remains at intervals, these disappear- 

 ing, and then only the half decayed remains reach farther out toward the 

 valley. In one place it was observed that the tops of these dead trees all 

 pointed to the east. This suggested the idea that the destruction may have 

 been due to one of the fierce west winds which, during the fall months, 

 are so prevalent in South Park. Once destroyed, other vegetation might 

 readily crowd the young trees out. A notable example of this was seen 

 in one portion of the foothills, where a whole forest of Pinus edulis lay 

 prostrate, with not a single young tree coming on. As bearing upon this 

 question of recession of the Conifers toward higher ground, I may also 

 remark that where these tongues of timber run down toward the centre of 

 the Park, the oldest trees are Coniferce and the younger growth is of cotton- 

 wood. This is especially marked at the lowest limit of the trees. Perhaps 

 mere "rotation of crop" may serve to explain the change, though I doubt it. 



The timber belt ends at about the greatest centre of development of 



