How far to the Rocky Mountains stretch?
The central and southern ranges of the Rocky Mountains are not like the abnormally sharpened peaks found in the ice-sculptured Alps. Many of these ranges are characterized by the rounded tops and the rather evenly slanting, waste-covered slopes which normally result from the long-continued action of the ordinary agencies of erosion. They bear little snow in summer and few if any glaciers. The forests are often scanty on the middle and lower slopes. The general impression of great altitude is much weakened because the mountains are seen from a base which itself is 5000 to 6000 feet (1,500 to 1,800 m) above sea level. Travelling along the range from south to north reveals most strikingly a gradual increase in the share of sculpture due to Pleistocene glaciers. In New Mexico, if glaciers were formed at all in the high valleys, they were so small as not to greatly to modify the more normal forms. In central Colorado and Wyoming, where the mountains are higher and the Pleistocene glaciers w
