Geologic units in Presidio county, Texas

Alluvium (Holocene) at surface, covers 20 % of this area

Alluvium

Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation (Oligocene) at surface, covers 18 % of this area

Perdiz Conglomerate, Tascotal Formation, and tuffaceous sediments of Fresno Formation

Bofecillos volcano volcanic rocks, including units 1-8 of Rawls Formation and lava flows in upper part of Fresno Formation (Oligocene) at surface, covers 10 % of this area

Bofecillos volcano volcanic rocks, including units 1-8 of Rawls Formation and lava flows in upper part of Fresno Formation

Chinati Mountains caldera volcanic rocks, including Chinati Mountains Group, Mitchell Mesa Ignimbrite, and type area of Petan Basalt (Oligocene) at surface, covers 8 % of this area

Chinati Mountains caldera volcanic rocks, including Chinati Mountains Group, Mitchell Mesa Ignimbrite, and type area of Petan Basalt

Quaternary-Tertiary bolson deposits (Pliocene to Pleistocene) at surface, covers 6 % of this area

Quaternary-Tertiary bolson deposits

Alluvial fan deposits (Pleistocene and Holocene) at surface, covers 6 % of this area

Alluvial fan deposits

Vieja Group, including Bracks Rhyolite, Chambers and Colmena Tuffs and Gill Breccia (Eocene to Oligocene) at surface, covers 6 % of this area

Vieja Group, including Bracks Rhyolite, Chambers and Colmena Tuffs and Gill Breccia

Older alluvial deposits (Pleistocene) at surface, covers 5 % of this area

Older alluvial deposits

Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation (Late Eocene) at surface, covers 4 % of this area

Infiernito caldera volcanic rocks including Capote Mountain Tuff, Tsh2 of Shely Group, Buckshot Ignimbrite, and Tm1 of Morita Ranch Formation

Jones Basalt (Oligocene) at surface, covers 2 % of this area

Jones Basalt

El Picacho Formation (Late Cretaceous) at surface, covers 2 % of this area

El Picacho Formation

Oligocene intrusive rocks (Oligocene) at surface, covers 1 % of this area

Oligocene intrusive rocks

Duff Formation (with Decie Member from Paisano caldera shown separately), Cottonwood Springs Basalt, Potato Hill Andesite, Sheep Canyon Basalt, Crossen Trachyte, and Pruett Formation, undivided (Late Eocene to Early Oligocene) at surface, covers 1 % of this area

Duff Formation (with Decie Member from Paisano caldera shown separaetly), Cottonwood Springs Basalt, Potato Hill Andesite, Sheep Canyon Basalt, Crossen Trachyte, and Pruett Formation, undivided

Tm2 and Tm3 units of Morita Ranch Formation (possibly from Cienega Mountain area) (Oligocene) at surface, covers 0.9 % of this area

Tm2 and Tm3 units of Morita Ranch Formation (possibly from Cienega Mountain area)

Upper part of Shely Group, including Tm4 or Morita Ranch Formation (Oligocene) at surface, covers 0.9 % of this area

Upper part of Shely Group, including Tm4 or Morita Ranch Formation

Duff Formation, Decie Member from Paisano caldera (Early Oligocene) at surface, covers 0.8 % of this area

Duff Formation, Decie Member from Paisano caldera

Devils Graveyard volcanic rocks (Eocene to Oligocene) at surface, covers 0.8 % of this area

Devils Graveyard volcanic rocks

Chisos Formation of Schiebout et al (1987) and the Big Yellow Sandstone Member of their Tornillo Formation, undivided (Eocene to Oligocene) at surface, covers 0.7 % of this area

Chisos Formation of Schiebout et al (1987) and the Big Yellow Sandstone Member of their Tornillo Formation, undivided

Younger volcanic rocks of Davis Mountains area including Brooks Mountain, Goat Canyon, Medley, Barrel Springs, Wild Cherry, Eppenaurer Ranch, Mount Locke, and Merrill Formations (Early Oligocene) at surface, covers 0.5 % of this area

Younger volcanic rocks of Davis Mountains area including Brooks Mountain, Goat Canyon, Medley, Barrel Springs, Wild Cherry, Eppenaurer Ranch, Mount Locke, and Merrill Formations

Santana Tuff from Sierra Rica caldera in Mexico (Oligocene) at surface, covers 0.5 % of this area

Santana Tuff from Sierra Rica caldera in Mexico

San Carlos Sandstone (Late Cretaceous) at surface, covers 0.4 % of this area

San Carlos Sandstone

Bluff Mesa Formation (Early Cretaceous) at surface, covers 0.4 % of this area

Bluff Mesa Formation; Western part of Trans-Pecos Texas.

Bouquillas Formation (Late Cretaceous) at surface, covers 0.4 % of this area

Bouquillas Formation

Santa Elena Limestone, Sue Peaks Formation, Del Carmen Limestone, and Telephone Canyon Formation, undivided (Early Cretaceous) at surface, covers 0.4 % of this area

Santa Elena Limestone, Sue Peaks Formation, Del Carmen Limestone, and Telephone Canyon Formation, undivided

Ojinaga Formation (Late Cretaceous) at surface, covers 0.4 % of this area

Ojinaga Formation

Eocene intrusive rocks (Eocene) at surface, covers 0.3 % of this area

Eocene intrusive rocks

Shafter Formation (Early Cretaceous) at surface, covers 0.3 % of this area

Shafter Formation

Tarantula Gravel (Miocene) at surface, covers 0.3 % of this area

Tarantula Gravel

Barnett Formation, Chappel Limestone, Houy, Zesch, Bear Spring, and Stribling Formations, and Pillar Bluff Limestone, undivided (Late; Middle; and Early Mississippian and Devonian) at surface, covers 0.3 % of this area

Barnett Formation, Chappel Limestone, Houy, Zesch, Bear Spring, and Stribling Formations, and Pillar Bluff Limestone, undivided

Santa Elena Limestone (Early Cretaceous) at surface, covers 0.2 % of this area

Santa Elena Limestone

Pinto Canyon Formation (Permian; Leonard and Guadalupe Series) at surface, covers 0.2 % of this area

Pinto Canyon Formation

Cox Sandstone (Early Cretaceous) at surface, covers 0.2 % of this area

Cox Sandstone

Yucca Formation (Early Cretaceous) at surface, covers 0.2 % of this area

Yucca Formation

Maxon Sandstone and Glen Rose Limestone, undivided (Early Cretaceous) at surface, covers 0.1 % of this area

Maxon Sandstone and Glen Rose Limestone, undivided

Alta Formation (Permian; Wolfcamp Series) at surface, covers 0.1 % of this area

Alta Formation

Del Carmen Limestone (Early Cretaceous) at surface, covers 0.1 % of this area

Del Carmen Limestone

Quaternary-Tertiary deposits, undivided (Pliocene to Pleistocene) at surface, covers 0.1 % of this area

Quaternary-Tertiary deposits, undivided

Presidio Formation (Early Cretaceous; Aptian; Albian Series) at surface, covers 0.1 % of this area

Presidio Formation

Black Gap area volcanic rocks (Miocene) at surface, covers < 0.1 % of this area

Black Gap area volcanic rocks

Loma Plata Formation (Early Cretaceous; Comanchean Series) at surface, covers < 0.1 % of this area

Loma Plata Formation

Benevides Formation and Finlay Limestone, undivided (Early Cretaceous; Comanchean Series) at surface, covers < 0.1 % of this area

Benevides Formation and Finlay Limestone, undivided

Cienequita Formation (Pennsylvanian; Middle and Late) at surface, covers < 0.1 % of this area

Cienequita Formation

Buda Limestone and Del Rio Clay, undivided (Late Cretaceous) at surface, covers < 0.1 % of this area

Buda Limestone and Del Rio Clay, undivided; Eastern part of Trans-Pecos and High Plains and Western part of Trans-Pecos and North, central, and south Texas including Quaternary for all of west Texas.

Sand deposits, undivided (Holocene) at surface, covers < 0.1 % of this area

Sand deposits, undivided

Ross Mine Formation (Permian; Guadalupe Series) at surface, covers < 0.1 % of this area

Ross Mine Formation

Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided (Cambrian and Ordovician) at surface, covers < 0.1 % of this area

Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided

Tesnus Formation (Early Pennsylvanian and Late Mississippian) at surface, covers < 0.1 % of this area

Tesnus Formation

Pen Formation (Late Cretaceous) at surface, covers < 0.1 % of this area

Pen Formation

Eocene volcanic rocks (Eocene) at surface, covers < 0.1 % of this area

Eocene volcanic rocks

Ordovician rocks, undivided (Ordovician) at surface, covers < 0.1 % of this area

Ordovician rocks, undivided

Mina Grande Formation (Permian; Guadalupe Series) at surface, covers < 0.1 % of this area

Mina Grande Formation

Sue Peaks Formation (Early Cretaceous) at surface, covers < 0.1 % of this area

Sue Peaks Formation

Cibolo Formation (Permian; Leonard Series) at surface, covers < 0.1 % of this area

Cibolo Formation

San Carlos Tuff from San Carlos caldera in Mexico (Oligocene) at surface, covers < 0.1 % of this area

San Carlos Tuff from San Carlos caldera in Mexico

Mississippi, Devonian, and Ordovician rocks, undivided (Mississippi; Devonian; and Ordovician) at surface, covers < 0.1 % of this area

Mississippi, Devonian, and Ordovician rocks, undivided

Land slide deposits (Pleistocene and Holocene) at surface, covers < 0.1 % of this area

Land slide deposits

Tertiary intrusive rocks, undivided (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks, undivided

Dimple Formation (Early Pennsylvanian) at surface, covers < 0.1 % of this area

Dimple Formation

Miocene intrusive rocks (Miocene) at surface, covers < 0.1 % of this area

Miocene intrusive rocks

Finlay Limestone (Early Cretaceous; Comanchean; Albian Series) at surface, covers < 0.1 % of this area

Finlay Limestone

Haymond Formation (Early Pennsylvanian) at surface, covers < 0.1 % of this area

Haymond Formation

Older volcanic rocks of Davis and Barilla Mountains, including Sheep Pasture, Sleeping Lion, Frazier Canyon, Adobe Canyon, and Limpia formations, Gomez Tuff, Star Mountain Rhyolite, and Huelster Formation (Late Eocene) at surface, covers < 0.1 % of this area

Older volcanic rocks of Davis and Barilla Mountains, including Sheep Pasture, Sleeping Lion, Frazier Canyon, Adobe Canyon, and Limpia formations, Gomez Tuff, Star Mountain Rhyolite, and Huelster Formation