There are three general categories on the map:1) more resistant units with lower erosional impact,2) softer units that can be disrupted and eroded relatively easily, and3) stream channels that have their surfaces refreshed when the channel flows with water.
The more resistant units include petrocalcic surfaces and pre-Tertiary limestones. Softer units include Tertiary basin sediments and Quaternary surfaces with pavements and an underlying loose silty layer. Stream channels are areas that have water flow annually to every decade or so and have the ability to refresh themselves and recover from the effects of vehicular traffic. The map is experimental and is a simple derivative map from the Geologic Map of the Ute Quadrangle (NBMG Map 177).