Cinder cones

When I was about seven or eight years old, my first memorable experience with climbing a "mountain" was a large cinder cone known as Cinder Knoll. Cinder hills are a common site on the Colorado Plateau and elsewhere in Arizona.  They are essentially huge piles of small rock-like cinders from a volcanic eruption.

This satellite view of the area north and west of Springerville, Arizona shows quite a number of cinder cones. The one I climbed as a young child is located further north and little more west of the cones in the photo.

Here is a side view of a cinder cone, in the same Springerville Volcanic Field.

Cinder cones form when the streaming gasses that carry lava to the surface form blobs in the atmosphere as the are ejected from the volcanic vent. They are generally mounds of basaltic scoria. The cones are considered very transient geologic structures because they have no internal structure and are easily eroded by rain water. The crater in the cone above has been breached by erosion.