Trail of the Mountain Spirits Scenic Byway
City of Rocks State Park, NM

Over a million years ago a nearby volcano erupted tiny particles of very hot rock. Instead of rising into the air they flowed from the lip of the volcano. When the flow came to rest, the particles fused together to form the solid rock found in the City of Rocks, known technically as 'welded tuff.'

Doubtless, the tuff was covered later by other volcanic material, but erosion acting through many thousands of years uncovered the tuff and attacked it. Because of its structure and composition, this rock scales off on the exposed surface.

Wind and water have carried off the volcanic debris, leaving these rounded monumental forms as a spectacle of the wonders of nature.