My assistant examines a core sample as we explore the area.
The next day we went down to see the Devil's Postpile. Although we hiked through the Monument a few days earlier, we never went over to see the pile itself. These hexagonal posts were formed from cooling lava.
Another look at the pile. As the leading edge is exposed to the elements, more posts fall forming the large pile below. On the next page I have a picture of the sign explaining the phenomenon.