The geological explanation for the formation of the tower is not certain. It is some sort of igneous intrusion into the landscape, but there are various theories as to how this happened. Some think it is the remnant of an old volcano. It is composed of phonolite porphyry which intruded about 40.5 million years ago. A characteristic feature are the vertical ridges which look like scratches left by a huge clawed creature. And indeed, Native American lore tells the story of two girls who climbed the tower to escape a bear which left its scratches in an effort to reach them.
The name "Devil's Tower" results (of course) from a mistake. In 1875, a European explorer misinterpreted a native name to mean "Bad God's Tower." Bad names stick, unfortunately.
I took several photos, but it was late evening and the details of the tower were in the shade. Nevertheless, I got a lovely shot with three deer grazing in the foreground. I'm including a commercial photo to show the "bear claw marks."
|My photo, taken at about 8:00 in the evening|
|The more iconic view showing vertical ridges|
|The iconic WPA/NP poster|