[5] Marine Cretaceous rocks of the Mancos Shale and Point Lookout Sandstone are exposed around the base of Cabezon Peak.

This stems from a Navajo myth which holds that it is the head of the giant Ye’i-tsoh after being slain by the twins Nayenezgani and To’badzistsini.

Cabezon Peak is the solidified core of a volcano that erupted 2.658 ± 0.032 million years ago, based on argon-argon dating.

The basalt that solidified from this lava contains visible crystals (phenocrysts) of olivine, clinopyroxene, plagioclase feldspar, and magnetite in a very fine-grained matrix.

[13] The basalt of Cabezon Peak contains a small number of xenoliths, fragments of solid rock that were entrained in the magma from the upper mantle or lower crust.