Devils Tower National Monument

Talk about iconic. Who doesn’t think of Close Encounters of the Third Kind when talking about Devils Tower? They even sell copies of the movie in the visitor center bookstore! Rising up from the plains, it is very distinctive. The striations in the sheer walls, nothing like it anywhere in sight, it is definitely unique.



In 1906, Devils Tower was the first National Monument created under the new Antiquities Act. It was set aside to preserve it from commercial exploitation. Trivia time: the act creating the Monument had a typo and dropped the apostrophe (Devil’s became Devils), thus the legal name is Devils. The name was assigned by Colonel Dodge in 1875. No one was calling it that. All the Indian tribes in the area had names associating it with bears – Bear Lodge, Bear’s Tipi, Bear’s Hat, Bear’s Home… Much better names in our opinion. They are trying to change the name to Bear Lodge, but that will take an act of congress. Literally.


The geology is actually still a bit of a mystery. All geologists agree that it was formed by magma being extruded into the surrounding layers of sedimentary rock beneath the earth’s surface (1.5 miles down actually). But there are several theories as to the actual type of intrusion. The simplest theory is a simple intrusion that just bubbled up, but couldn’t make it to the surface, called a stock. Next up is a bit bigger intrusion, called a laccolith, or a mushroom shaped intrusion that subsequently cools underground like the stock.  Another one is that it is the remnant of a volcano or a plug.

So whichever one it is, the end result is the same. The magma cooled and crystalized into a rock called phonolite porphyry. Basically it is a dark grey rock with noticeable feldspar crystals. While cooling it split along stress lines and formed into ginormous columns of 5 and 6 sided rocks. This columnar formation is the largest in the world.

Now, we have a giant plug of igneous rock sitting underground all covered up.  Continental uplifting has to occur and erosion and all that jazz has to happen to remove all the rock around it. If you thought it was a lot of soil movement before at Scotts Bluff, this is even bigger.

(Hey, sorry for the nerdy geology lecture, but what can you say when the author is a former geology major?)

We found an interesting intersection of Indian Lore and geology at one of the information placards along the trail we hiked. It talked about a great race where the animals raced to see which was most powerful. They ran until their mouths and hoofs bled, staining the earth red. Also on that placard, was a topo map of 1869 showing the Spearfish formation, which is a red-rock layer, surrounding the Black Hills area. That was a fascinating juxtaposition.


This was a very busy park. A lot of people were there. It’s the first time we saw so many at once at a park. We hiked the Tower Trail around the base. It gave plenty of great vantage points of the Tower. No pets are allowed on any of the trails, so we left Kip and Kellie home this trip. Bev went back the next morning at “zero dark thirty” to get some more pics because, of course, we were there close to noon and the sky was a bit blown out.



One thought on “Devils Tower National Monument”

  1. Really cool pics. Thanks for the geology lesson. Something I didn’t know☺

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