Most of the timber which occurs on any part of the mountain is evergreen, consisting of several species of abies, among which may be enumerated the balsam fir (A. balsamea, Ph.); the hemlock, white, red, and black spruce (A. canadensis, A. alba, A. rubra, and A. nigra); the red cedar, and common juniper; and a few pines. One of these, which appears to have been hitherto unnoticed in North America, has, like the great white or Weymouth pine, five leaves in a fascicle; but in other respects there is little resemblance between them. The leaves are short and rather rigid; the sheaths which surround their bases short and lacerated; the strobiles erect, composed of large unarmed scales, being somewhat smaller than those of P. rigida, but similar in shape, and exuding a great quantity of resin. The branches, which are covered with leaves chiefly at the ends, are numerous and recurved, inclining to form a dense and large top; they are also remarkably flexile, feeling in the hand somewhat like those of the dirca palustris, L. From this circumstance, the specific name, flexilis, has been proposed for this tree; which is, in several respects, remarkably contrasted with the P. rigida. It inhabits the arid plains subjacent to the Rocky Mountains, and extends up their sides to the region of perpetual frost. The {225} fruit of the pinus flexilis is eaten by the Indians and the French hunters, as that of another species of the same genus is eaten by the inhabitants of some parts of Europe. The creek on which the party encamped during the three days occupied in making the excursion above detailed, is called Boiling-spring creek, having one of its principal sources in the beautiful spring already described.[10] It is skirted with a narrow margin of cotton-wood and willow trees; and its banks produce a small growth of rushes, on which our horses subsisted principally, while we lay encamped here. This plant, the common rush (equisetum hyemale, Ph.), found in every part of the United States, is eaten with avidity by horses, and is often met with in districts where little grass is to be had. When continued for a considerable time its use proves deleterious. The recent track of a grizzly bear was observed near the camp; and at no great distance one of those animals was seen and shot at by one of the hunters, but not killed. In the timber along the creek, the sparrow-hawk, mocking-bird, robin, red-head woodpecker, Lewis' woodpecker, dove, winter wren, towhe, bunting, yellow-breasted chat, and several other birds were seen. Orbicular lizards were found about this camp, and had been once or twice before noticed near the base of the mountains.