Geologic units in Grand county, Utah

Glen Canyon Group (Early Jurassic) at surface, covers 15 % of this area

Glen Canyon Group (Navajo Ss, Kayenta Fm, and Wingate Ss). Includes Rainbow Bridge.

Mancos Shale (Late Cretaceous) at surface, covers 14 % of this area

Mancos Shale (Masuk Shale Mbr, Emery Sandstone Mbr, Blue Gate Shale Mbr, Ferron Sandstone Mbr, and Tununk Shale Mbr).

Wasatch/Colton Formations and Flagstaff Limestone (Early to Middle Eocene) at surface, covers 13 % of this area

Wasatch/Colton Formations and Flagstaff Limestone.

Mesaverde Group (Late Cretaceous) at surface, covers 12 % of this area

Mesaverde Group.

Eastern Uinta Basin Members of the Green River Formation (Eocene) at surface, covers 11 % of this area

Eastern Uinta Basin Members of the Green River Formation (Evacuation Creek Mbr, Parachute Creek Mbr (oil shale), Garden Gulch Mbr, and Douglas Creek Mbr.).

Morrison Formation (Brushy Basin and Salt Wash Members) (Late Jurassic) at surface, covers 6 % of this area

Morrison Formation (Brushy Basin and Salt Wash Members).

Bluff Ss, Summerville Fm, Curtis Fm, Entrada Ss, and Carmel Formation (Middle to Late Jurassic) at surface, covers 6 % of this area

Bluff Ss, Summerville Fm, Curtis Fm, Entrada Ss, and Carmel Formation. Includes Arches National Park.

Alluvium and colluvium (Quaternary) at surface, covers 5 % of this area

Alluvium and colluvium

Eolian deposits (Quaternary) at surface, covers 5 % of this area

Eolian deposits

Dakota Ss and Cedar Mtn. or Burro Canyon Formations (Cretaceous) at surface, covers 4 % of this area

Dakota Ss and Cedar Mtn or Burro Canyon Formations.

Older alluvial deposits (Quaternary) at surface, covers 3 % of this area

Older alluvial deposits

Chinle Shale and Shinarump Conglomerate Member (Late Triassic) at surface, covers 2 % of this area

Chinle Shale and Shinarump Conglomerate Member.

Cutler Group (Pennsylvanian to Early Permian) at surface, covers 1 % of this area

Cutler Group (White Rim Ss, De Chelly Ss, Organ Rock Shale, Cedar Mesa Ss, Halgaito Fm, and Elephant Canyon Fm). Includes Natural Bridges National Monument.

Moenkopi Formation (Early Triassic) at surface, covers 1.0 % of this area

Moenkopi Formation.

Schist, gneiss, and granite (Precambrian) at surface, covers 0.6 % of this area

Schist, gneiss, and granite (1.5 billion years old).

Laccolithic intrusions mostly diorite porphyry (Oligocene) at surface, covers 0.4 % of this area

Laccolithic intrusions mostly diorite porphyry (24-28 my).

North Horn and Currant Creek Formations (Late Cretaceous to Paleocene) at surface, covers 0.3 % of this area

North Horn and Currant Creek Formations.

Rico Formation (Pennsylvanian to Permian) at surface, covers 0.3 % of this area

Rico Formation.

Glacial deposits (Quaternary) at surface, covers 0.1 % of this area

Glacial deposits

Landslides (Quaternary) at surface, covers 0.1 % of this area

Landslides

Castle Valley Conglomerate (Pliocene) at surface, covers 0.1 % of this area

Castle Valley Conglomerate.

Crazy Hollow Formation (Eocene) at surface, covers < 0.1 % of this area

Crazy Hollow Formation.

Hermosa Group and Molas Formation (Mississipian to Pennsylvanian) at surface, covers < 0.1 % of this area

Hermosa Group (Honaker Trail Fm, Paradox Fm (oil, salt, potash), Pinkerton Trail Fm) and Molas Formation.

Morrison Fm, Summerville Fm, and Entrada Sandstone (Jurassic) at surface, covers < 0.1 % of this area

Summerville Fm: Shale and siltstone

Dakota Sandstone and Burro Canyon Fm (Cretaceous) at surface, covers < 0.1 % of this area

Sandstone, shale, and conglomerate. In northwest and west-central: Lower Cretaceous. In southwest: Lower and Upper Cretaceous.

Glen Canyon Group and Chinle Fm (Jurassic-Triassic) at surface, covers < 0.1 % of this area

In southwest, Glen Canyon Group consists of Navajo Sandstone, Kayenta Fm (red siltstone, shale, and sandstone) and Wingate Sandstone; Chinle is red siltstone

Modern alluvium (Quaternary) at surface, covers < 0.1 % of this area

Includes Piney Creek Alluvium and younger deposits

Moenkopi Fm and Cutler Fm (Triassic-Permian) at surface, covers < 0.1 % of this area

Red siltstone and sandstone