The core of the mountains is mostly composed of metasedimentary Paleozoic rocks.

The spectacularly eroded walls of the canyon are formed mostly of Paleozoic sedimentary rocks.

The thickness of these strata is greater than that of all earlier Paleozoic rocks.

Below the sand are Paleozoic rocks of the Perth Basin.

They are found only in Paleozoic rocks.

The regional dip of the Paleozoic rocks is gentle, around 10 to the west.

The diverse geology of the Refuge includes Paleozoic metamorphic rock in the western sections.

Biotite is the most prevalent Paleozoic metamorphic rock in the region.

The predominant rocks are granite and slate, both very old Paleozoic rocks.

The Paleozoic rocks were deformed and thrust into the area from the southeast during the Ouachita orogeny.