Transported by wind more than 100 million years ago, tiny grains of sand covered much of what we now call Utah. These sand dunes were cemented into stone which were, at times over 2000 ft high. . Burnt orange to white in color, Navajo sandstone, is what remains of the ancient desert sand sea. Over time, water has cut and shaped the sandstone to form canyons. 

Approximately 1 million years ago, and as recently as 20,000 years ago, nearby cinder cones erupted, causing lava to flow down these canyons, filling them with basalt. 

This redirected ancient waterways, eventually carving new canyons. Look up to see lava-capped ridges that were once canyon bottoms. 

There are some nice climbing routes in the area that we stopped at to check out on the way to Vegas as well as a few lava tubes that can be found on the lava flow trail.

The lava tubes are very small to only a few hundred feet in horizontal length which also have some significant damage from people that went into the caves to party and spray paint gold glittered spray paint that had me fooled for fools gold for almost 10 minutes. 

Its a great place to stop through if you are in the St. George area and I recommend at least a half day for the lava flows.