All the Rocky Mountain lakes are glacier lakes. There are more than a thousand of these. The basins of the majority of them were excavated by ice from solid rock. Only a few of them have more than forty acres of area, and, with the exception of a very small number, they are situated well up on the shoulders of the mountains and between the altitudes of eleven thousand and twelve thousand feet. The lower and middle slopes of the Rockies are without lakes.
The lower third of the mountains, that is, the foothill section, is only tree-dotted. But the middle portion, that part which lies between the altitudes of eight thousand and eleven thousand feet, is covered by a heavy forest in which lodge-pole pine, Engelmann spruce, and Douglas spruce predominate. Fire has made ruinous inroads into the primeval forest which grew here.
A large portion of the summit-slopes of the mountains is made up of almost barren rock, in old moraines, glaciated slopes, or broken crags, granite predominating. These rocks are well tinted
with lichen, but they present a barren appearance. In places above the altitude of eleven thousand feet the mountains are covered with a profuse array of alpine vegetation. This is especially true of the wet meadows or soil-covered sections that are continually watered by melting snows.
In the neighborhood of a snowdrift, at an altitude of twelve thousand feet, I one day gathered in a small area one hundred and forty-two varieties of plants. Areas of "eternal snows," though numerous, are small, and with few exceptions, above twelve thousand feet. Here and there above timber-line are many small areas of moorland, which, both in appearance and in vegetation, seem to belong in the tundras of Siberia.
While these mountains carry nearly one hundred varieties of trees and shrubs, the more abundant kinds of trees number less than a score. These are scattered over the mountains between the altitudes of six thousand and twelve thousand feet, while, charming and enlivening the entire mountain-section, are more than a thousand varieties of wild flowers.
Bird-life is abundant on the Rockies. No State east of the Mississippi can show as great a variety as Colorado. Many species of birds well known in the East are found there, though, generally, they are in some way slightly modified. Most Rocky Mountain birds sound their notes a trifle more loudly than their Eastern relatives. Some of them are a little larger, and many of them have their colors slightly intensified.
Many of the larger animals thrive on the slopes of the Rockies. Deer are frequently seen. Bobcats, mountain lions, and foxes leave many records. In September bears find the choke-cherry bushes and, standing on their hind legs, feed eagerly on the cherries, leaves, and good-sized sections of the twigs. The ground-hog apparently manages to live well, for he seems always fat. There is that wise little fellow the coyote. He probably knows more than he is given credit for knowing, and I am glad to say for him that I believe he does man more good than harm. He is a great destroyer of meadow mice. He digs out gophers. Sometimes his meal is made upon rabbits or grasshoppers, and I have seen him feeding upon wild plums.