Just a quick posting of a wonderful rock formation in Yellowstone National Park. Note the two layers of columnar lava rock. Recall the Devil’s Causeway in Northern Ireland or Devil’s Tower a couple of hundred miles to the east of Yellowstone in Wyoming. That Devil was a hard working demon.

Slow solidification and shrinkage of the cooling lava flows from earlier vulcanism led to this columnar structure. There is a pull-off across the road next to what must be the upper layer where the photo was taken. I skipped across the road to get a closer look. After 5 minutes I noticed the sign warning not to go next to the formation due to the danger of falling rock. At least there wasn’t a bison standing there as well.