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 Cation 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 Conifere 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 Conifere 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 Conifere 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 
