Missouri Buttes
Those two lumps off to the left (West) of the Devil's Tower are the Missouri Buttes. What is interesting is that they are of the same material as the Devils Tower and date to the same period (40.5 million years). They actually are taller than the Devil's Tower by a few hundred feet. Now imagine... if these formations were from the same volcano and they are 3.5 miles away.... This was a pretty good-sized volcano. Just to put it into perspective, Yellowstone is a youngster. the Volcano that exploded to make the current Yellowstone caldera did so a mere 640,000 years ago. The theorized magma plume that forms the heat source for Yellowstone has moved across the bottom of Idaho for a few million years, only 16 millions of years ago the Yellowstone plume was located at the border or Oregon & Nevada. Why are they called the Missouri Buttes? Well. the Little Missouri river is about 15 miles further to the NorthWest.
National Monument
Missouri Buttes