The columns present an interesting problem. They appear to have been produced in the rapidly cooling volcanic rock by regularly arranged cracks which were due to contraction of the cooling mass. The fact that they are not well developed in the base of the Tower may be due to the slower cooling of the more deeply buried part. The flare of the columns is a subject too involved for this brief account. As to the age of the Tower it is believed to have been formed early in the Age of Mammals, perhaps 50 million years ago, but to have been uncovered by erosion only in the last one or two million years. _Plant and Animal Life_ About a half mile from the entrance to Devils Tower National Monument the visitor finds himself driving through a thriving prairie dog “town.” These animals were as typical of the original West as the buffalo. Their presence in towns covering several square miles was incompatible with agriculture, and the elimination of the species has progressed to the point where they are now rarely found. Since all forms of plant and animal life are protected within national monuments, this colony of prairie dogs gives one a glimpse of the Old West. Mule deer may be seen occasionally, and also many small animals including cottontails and chipmunks. A wide diversity of weather conditions, soil, and elevation, and the location of the monument between the mountains and plains, produce an interesting and extensive fauna and flora. These factors, together with interesting geological problems, afford the student of natural history a wealth of observation and information if he will but take the time to follow not only the trail which encircles the Devils Tower proper but the 4½ miles of nature trail as well. [Illustration: _Devils Tower and the Belle Fourche River_] [Illustration: _Distant view of Devils Tower_] [Illustration: _Fragments of fallen columns at base of Devils Tower_] _The Monument Museum_ Many questions come to those who view Devils Tower, and an effort is made to answer them through exhibits in the museum at the parking area. There, by use of pictures, diagrams, artifacts, and specimens, is presented an explanation of some of the features of the Tower, its geology, setting, history, and legend. These exhibits, of interest to the layman and student alike, are a logical prelude to a walk along the trails. _Location and Facilities_ Located a little west of the center of Crook County, which lies in the northeast corner of Wyoming, the monument entrance is 7 miles northward from U. S. Highway 14, 29 miles northwest of Sundance, Wyo., and 33 miles northeast of Moorcroft, Wyo.