They lie primarily within the Gunnison National Forest, and part of the range is protected as the West Elk Wilderness.

A large stratovolcano and other vents ejected material that accumulated over what is now the southern West Elk Mountains.

These welded tuffs are more resistant to weathering than the underlying breccia and today they cap multiple south-sloping mesas in the southern West Elk Mountains.

Stratigraphic profiles of these rock layers can be seen at the southern edge of the West Elk Mountains where the Gunnison River has eroded through the volcanic strata.

The resistant welded tuff that caps Dillon Mesa is on top, overlying the West Elk Breccia, which has eroded into the pinnacles.