Geologic units in California (state in United States)

Additional scientific data in this geographic area

Quaternary alluvium and marine deposits (Pliocene to Holocene) at surface, covers 21 % of this area

Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.

Plio-Pleistocene and Pliocene loosely consolidated deposits (Miocene to Pleistocene) at surface, covers 6 % of this area

Pliocene and/or Pleistocene sandstone, shale, and gravel deposits; in part Miocene.

Tertiary volcanic flow rocks, unit 17 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 5 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary pyroclastic and volcanic mudflow deposits, unit 9 (Cascade Range) (Tertiary (2-24 Ma)) at surface, covers 4 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Quaternary volcanic flow rocks, unit 1 (Cascade Volcanic Field) (Quaternary) at surface, covers 3 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Franciscan Complex, unit 1 (Coast Ranges) (Jurassic to Cretaceous) at surface, covers 3 % of this area

Franciscan complex: Cretaceous and Jurassic sandstone with smaller amounts of shale, chert, limestone, and conglomerate. Includes Franciscan melange, except where separated--see KJfm.

Miocene marine rocks (Oligocene to Pliocene) at surface, covers 3 % of this area

Sandstone, shale, siltstone, conglomerate and breccia; in part Pliocene and Oligocene.

Mesozoic granitic rocks , unit 2 (Peninsular Ranges) (Middle Jurassic to Late Cretaceous) at surface, covers 2 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Tertiary-Cretaceous Coastal Belt Rocks (Late Cretaceous to Pliocene) at surface, covers 2 % of this area

Sandstone, shale and minor conglomerate in coastal belt of northwestern California; included by some in Franciscan Complex. Previously considered Cretaceous, but now known to contain early Tertiary microfossils in places.

Paleozoic marine rocks, undivided, unit 9 (Western Klamath Mountains) (Devonian to Jurassic) at surface, covers 2 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Upper Cretaceous marine rocks, unit 1 (Upper Great Valley Sequence) (Late Cretaceous) at surface, covers 2 % of this area

Upper Cretaceous sandstone, shale, and conglomerate

Tertiary volcanic flow rocks, unit 16 (Northern Mojave Desert) (Tertiary (4-22 Ma)) at surface, covers 2 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

pre-Cenozoic metasedimentary and metavolcanic rocks undivided (Early Proterozoic to Cretaceous) at surface, covers 2 % of this area

Undivided pre-Cenozoic metasedimentary and metavolcanic rocks of great variety. Mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and minor marble.

Eocene marine rocks (Paleocene to Oligocene) at surface, covers 1 % of this area

Shale, sandstone, conglomerate, and minor limestone; in part Oligocene and Paleocene.

Pliocene marine rocks (Miocene to Pleistocene) at surface, covers 1 % of this area

Sandstone, siltstone, shale, and conglomerate; in part Pleistocene and Miocene.

Quaternary sand deposits, unit 2 (inland) (Quaternary) at surface, covers 1 % of this area

Extensive marine and nonmarine sand deposits, generally near the coast or desert playas

Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains) (Jurassic) at surface, covers 1 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Lower Cretaceous marine rocks (Early Cretaceous) at surface, covers 1 % of this area

Lower Cretaceous sandstone, shale, and conglomerate

Franciscan melange (Jurassic to Cretaceous) at surface, covers 1 % of this area

Melange of fragmented and sheared Franciscan complex rocks.

Lithology: melange

Franciscan schist (Early Cretaceous) at surface, covers 1 % of this area

Blueschist and semi-schist of Franciscan complex

Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains) (Triassic to Late Jurassic) at surface, covers 1 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Precambrian rocks, undivided, unit 2 (Mojave Desert and Transverse Ranges) (Early Proterozoic to Miocene) at surface, covers 1 % of this area

Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part

pre-Cenozoic granitic and metamorphic rocks undivided (Early Proterozoic to Late Cretaceous) at surface, covers 1 % of this area

Granitic and metamorphic rocks, mostly gneiss and other metamorphic rocks injected by granitic rocks. Mesozoic to Precambrian.

Mesozoic granitic rocks, unit 5 (Klamath Mountains) (Jurassic to early Cretaceous) at surface, covers 1.0 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Quaternary glacial deposits (Pleistocene) at surface, covers 1.0 % of this area

Glacial till and moraines. Found at high elevations mostly in the Sierra Nevada and Klamath Mountains.

Lithology: glacial drift

Cambrian marine rocks (Late Proterozoic to Middle Devonian) at surface, covers 1.0 % of this area

Sandstone, shale, limestone, dolomite, chert, quartzite, and phyllite; includes some rocks that are possibly Precambrian

Precambrian rocks, undivided, unit 1 (Death Valley) (Early Proterozoic to Mesozoic) at surface, covers 0.9 % of this area

Conglomerate, shale, sandstone, limestone, dolomite, marble, gneiss, hornfels, and quartzite; may be Paleozoic in part

Recent (Holocene) volcanic flow rocks, unit 1 (Cascade Volcanic Field) (Holocene) at surface, covers 0.9 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: andesite; dacite

Precambrian igneous and metamorphic rock complex (Early Proterozoic to Miocene) at surface, covers 0.9 % of this area

Complex of Precambrian igneous and metamorphic rocks. Mostly gneiss and schist intruded by igneous rocks; may be Mesozoic in part.

Undivided pre-Cenozoic metavolcanic rocks, unit 2 (undivided) (Paleozoic(?) to Mesozoic(?)) at surface, covers 0.8 % of this area

Undivided pre-Cenozoic metavolcanic rocks. Includes latite, dacite, tuff, and greenstone; commonly schistose.

Paleozoic marine rocks, undivided, unit 4 (Western Sierra Nevada) (Ordovician to Triassic) at surface, covers 0.8 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Mesozoic gabbroic rocks, unit 2 (undivided) (Triassic to Cretaceous) at surface, covers 0.7 % of this area

Gabbro and dark dioritic rocks; chiefly Mesozoic

Lithology: gabbro; diorite

Ultramafic rocks, chiefly Mesozoic, unit 2 (Western Sierra Nevada and Klamath Mountains) (Late Proterozoic(?) to Early Jurassic) at surface, covers 0.7 % of this area

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 2

Ultramafic rocks, chiefly Mesozoic, unit 3 (Coast Ranges and Western Klamath Mountains) (Middle to Late Jurassic) at surface, covers 0.6 % of this area

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 3

Carboniferous marine rocks, unit 4 (Eastern Klamath Mountains) (Mississippian to Early Permian) at surface, covers 0.6 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Tertiary nonmarine rocks, undivided (Paleocene to Pliocene) at surface, covers 0.6 % of this area

Undivided Tertiary sandstone, shale, conglomerate, breccia, and ancient lake deposits.

Quaternary volcanic flow rocks, unit 1, questionably identified (Cascade Volcanic Field) (Quaternary) at surface, covers 0.5 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Miocene nonmarine rocks (Oligocene to Pleistocene) at surface, covers 0.5 % of this area

Sandstone, shale, conglomerate, and fanglomerate; in part Pliocene and Oligocene.

Mesozoic granitic rocks, unit 1 (Salinian Block) (Early to Late Cretaceous) at surface, covers 0.4 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Mesozoic volcanic rocks, unit 3 (Mojave Desert, Death Valley area, and Eastern Sierra Nevada) (Triassic to Cretaceous) at surface, covers 0.4 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Ultramafic rocks, chiefly Mesozoic, unit 1 (Trinity Ophiolite) (Ordovician) at surface, covers 0.4 % of this area

Ultramafic rocks, mostly serpentine. Minor peridotite, gabbro, and diabase. Chiefly Mesozoic unit 1

Schist of various types and ages, unit 7 (Klamath Mountains) (Devonian) at surface, covers 0.4 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist; amphibolite; marble

Mesozoic volcanic rocks, unit 1 (Coast Ranges) (Jurassic to Cretaceous) at surface, covers 0.4 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Oligocene nonmarine rocks, unit 2 (Central and Southern California) (middle Eocene to early Miocene) at surface, covers 0.3 % of this area

Sandstone, shale, and conglomerate; in part Miocene and Eocene.

Paleozoic metavolcanic rocks, unit 1 (Eastern Klamath Mountains) (Devonian and Permian) at surface, covers 0.3 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Quaternary pyroclastic and volcanic mudflow deposits, unit 2 (Long Valley Caldera) (Quaternary (0-1 Ma)) at surface, covers 0.3 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Paleocene marine rocks, unit 2 (Northern California) (Paleocene to late Eocene) at surface, covers 0.3 % of this area

Sandstone, shale, and conglomerate; mostly well consolidated

Tertiary pyroclastic and volcanic mudflow deposits, unit 8 (Northern Mojave Desert) (Tertiary (4-22 Ma)) at surface, covers 0.3 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Schist of various types and ages, unit 2 (Southern and West-central California) (Late Cretaceous to Eocene) at surface, covers 0.3 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Triassic marine rocks, unit 2 (Eastern Klamath Mountains) (Middle to Late Triassic) at surface, covers 0.3 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Tertiary volcanic flow rocks, unit 3 (Sonoma Volcanic Field) (Tertiary (3-7 Ma)) at surface, covers 0.3 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Jurassic marine rocks, unit 2 (Coast Ranges) (Late Jurassic to Early Cretaceous) at surface, covers 0.3 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Silurian and/or Ordovician marine rocks, unit 1 (Death Valley) (Ordovician to Early Devonian) at surface, covers 0.3 % of this area

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

Precambrian granitic rocks, unit 1 (Eastern Mojave Desert) (Early Proterozoic to Miocene) at surface, covers 0.2 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California

Eocene nonmarine rocks, unit 1 (Northern and Central California) (Eocene) at surface, covers 0.2 % of this area

Sandstone, shale, and conglomerate.

Tertiary volcanic flow rocks, unit 18 (San Joaquin-Kings Canyon) (Tertiary (3-4 Ma)) at surface, covers 0.2 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Mesozoic volcanic rocks, unit 4 (Peninsular Ranges) (Late Jurassic to Early Cretaceous) at surface, covers 0.2 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Mesozoic volcanic rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Late Permian(?) to Jurassic) at surface, covers 0.2 % of this area

Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks

Schist of various types and ages, unit 8 (Condrey Mountain) (Jurassic(?)) at surface, covers 0.2 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Paleozoic marine rocks, undivided, unit 6 (Northwestern Sierra Nevada) (Permian(?) to Jurassic(?)) at surface, covers 0.2 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Quaternary volcanic flow rocks, unit 5 (Coso Volcanic Field) (Quaternary (0-4 Ma)) at surface, covers 0.2 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Tertiary volcanic flow rocks, unit 15 (Southern Mojave Desert) (Tertiary (8-28 Ma)) at surface, covers 0.2 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Jurassic marine rocks, unit 5 (Northern Sierra Nevada and Eastern Klamath Mountains) (Devonian to Late Jurassic) at surface, covers 0.2 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Paleocene marine rocks, unit 1 (Central and Southern California) (Paleocene) at surface, covers 0.2 % of this area

Sandstone, shale, and conglomerate; mostly well consolidated

Jurassic marine rocks, unit 4 (Peninsular Ranges and Western Transverse Ranges) (Paleozoic(?) to Late Jurassic) at surface, covers 0.2 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Paleocene marine rocks, unit 3 (La Panza Range) (Late Cretaceous(?) to Eocene(?)) at surface, covers 0.2 % of this area

Sandstone, shale, and conglomerate; mostly well consolidated

Quaternary sand deposits, unit 1 (coastal) (Quaternary) at surface, covers 0.2 % of this area

Extensive marine and nonmarine sand deposits, generally near the coast or desert playas

Lithology: dune sand; beach sand

Upper Cretaceous and Paleocene marine rocks, undivided (Late Cretaceous to Paleocene) at surface, covers 0.2 % of this area

Sandstone, shale, and conglomerate

Tertiary intrusive rocks (hypabyssal), unit 7 (Northern Mojave Desert) (Tertiary) at surface, covers 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Mesozoic gabbroic rocks, unit 1 (Trinity Ophiolite) (Ordovician) at surface, covers 0.1 % of this area

Gabbro and dark dioritic rocks; chiefly Mesozoic

Lithology: gabbro; diorite

Cretaceous marine rocks (in part nonmarine), unit 1 (Coast Ranges) (Early to Late Cretaceous) at surface, covers 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges

Quaternary volcanic flow rocks, unit 7 (Mojave Desert) (Quaternary) at surface, covers 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Paleozoic metavolcanic rocks, unit 2 (Northeastern Sierra Nevada) (Devonian and Permian) at surface, covers 0.1 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Tertiary volcanic flow rocks, unit 8 (Southern California Basin) (Tertiary (8-25 Ma; most near 15)) at surface, covers 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Paleozoic marine rocks, undivided, unit 1 (Mojave Desert and Death Valley area) (Late Proterozoic to Jurassic) at surface, covers 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Carboniferous marine rocks, unit 3 (SE California Clastic Assemblage) (Late Devonian to Early Permian) at surface, covers 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Quaternary volcanic flow rocks, unit 3 (Clear Lake Volcanic Field) (Quaternary (0-4 Ma)) at surface, covers 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Lithology: andesite; dacite; basalt

Devonian marine rocks, unit 1 (Death Valley) (Middle to Late Devonian) at surface, covers 0.1 % of this area

Limestone and dolomite, sandstone and shale; in part tuffaceous

Quaternary volcanic flow rocks, unit 2 (Long Valley Caldera) (Quaternary) at surface, covers 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Lithology: rhyolite; andesite; basalt

Paleozoic and Permo-Triassic granitic rocks unit 2 (San Gabriel Mountains) (Late Triassic) at surface, covers 0.1 % of this area

Paleozoic and Permo-Triassic granitic rocks in the San Gabriel and Klamath Mountains

Oligocene marine rocks (Eocene to Miocene) at surface, covers 0.1 % of this area

Sandstone, shale, and conglomerate; in part Miocene and Eocene.

Carboniferous marine rocks, unit 2 (SE California Carbonate Assemblage) (Mississippian to Early Permian) at surface, covers 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Eocene nonmarine rocks, unit 2 (Southern California) (middle to late Eocene) at surface, covers 0.1 % of this area

Sandstone, shale, and conglomerate.

Lithology: conglomerate; sandstone

Permian marine sedimentary rocks, unit 1 (Death Valley and Mojave Desert) (Pennsylvanian to Triassic) at surface, covers 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Paleozoic metavolcanic rocks, unit 3 (Northwestern Sierra Nevada) (Permian to Jurassic) at surface, covers 0.1 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Precambrian granitic rocks, unit 2, (San Gabriel Mountains Anorthosite) (Middle Proterozoic) at surface, covers 0.1 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California

Lithology: anorthosite; gabbro; syenite

Cenozoic (Tertiary) granitic rocks, unit 1 (Death Valley) (middle to late Miocene) at surface, covers < 0.1 % of this area

Cenozoic (Tertiary) granitic rocks--quartz monzonite, quartz latite, and minor monzonite, granodiorite, and granite; found in the Kingston, Panamint, Amargosa, and Greenwater Ranges in southeastern California.

Oligocene nonmarine rocks, unit 1 (Northern California) (Oligocene to Miocene) at surface, covers < 0.1 % of this area

Sandstone, shale, and conglomerate; in part Miocene and Eocene.

Limestone of probable Paleozoic or Mesozoic age (Paleozoic to Mesozoic) at surface, covers < 0.1 % of this area

Limestone, dolomite, and marble whose age is uncertain but probably Paleozoic or Mesozoic

Silurian and/or Ordovician marine rocks, unit 3 (Eastern Klamath Mountains) (Ordovician to Early Devonian) at surface, covers < 0.1 % of this area

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

Quaternary volcanic flow rocks, unit 6 (Sierra Nevada) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Lithology: basalt; andesite

Undated granitic rocks, unit 3 (Southern California) (Jurassic(?) to Cretaceous(?)) at surface, covers < 0.1 % of this area

Undated granitic rocks unit 3

Tertiary volcanic flow rocks, unit 1 (Quien Sabe-Burdell Mountain) (Tertiary (9.5-13 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Mesozoic granitic rocks, unit 4 (Klamath Mountains and Northern Sierra Nevada) (Devonian) at surface, covers < 0.1 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Recent (Holocene) volcanic flow units, unit 4 (Mojave Desert) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 2 (Mono Craters) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.

Cretaceous marine rocks (in part nonmarine) (?), unit 1 (Blythe) (Middle Jurassic(?) to Late Cretaceous) at surface, covers < 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges (?)

Schist of various types and ages, unit 1 (Peninsular Ranges) (Triassic(?)) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian

Quaternary large landslide deposits (Quaternary) at surface, covers < 0.1 % of this area

Selected large landslides, such as Blackhawk slide on north side of San Gabriel Mountains; early to late Quaternary.

Lithology: landslide

Devonian marine rocks, unit 2 (Eastern Klamath Mountains) (Devonian) at surface, covers < 0.1 % of this area

Limestone and dolomite, sandstone and shale; in part tuffaceous

Undivided pre-Cenozoic metavolcanic rocks, unit 1 (Southwestern Sierra Nevada) (Ordovician(?) to Permian(?)) at surface, covers < 0.1 % of this area

Undivided pre-Cenozoic metavolcanic rocks. Includes latite, dacite, tuff, and greenstone; commonly schistose.

Undated granitic rocks, unit 1 (Chocolate Mountains) (Oligocene to Miocene) at surface, covers < 0.1 % of this area

Undated granitic rocks unit 1

Upper Cretaceous marine rocks, unit 2 (Klamath Mountains) (late Early to Late Cretaceous) at surface, covers < 0.1 % of this area

Upper Cretaceous sandstone, shale, and conglomerate

Carboniferous marine rocks, unit 1 (Western Mojave Desert) (Late Proterozoic to Pennsylvanian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Triassic marine rocks, unit 3 (Lake Almanor) (Permian to Jurassic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Paleozoic marine rocks, undivided, unit 2 (Northern Mojave Desert and Southeastern Sierra Nevada) (Cambrian to Jurassic) at surface, covers < 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Recent (Holocene) volcanic flow rocks, unit 2 (Mono Craters) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: rhyolite

Paleozoic marine rocks, undivided, unit 3 (Eastern Sierra Nevada) (Late Proterozoic(?) to Mesozoic(?)) at surface, covers < 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Tertiary pyroclastic and volcanic mudflow deposits, unit 1 (Sonoma Volcanic Field) (Tertiary (3-7 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Quaternary pyroclastic and volcanic mudflow deposits, unit 3 (Sutter Buttes) (Quaternary (1.5-2.5 Ma)) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Tertiary intrusive rocks (hypabyssal), unit 1 (Cascades Volcanic Field) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Tertiary pyroclastic and volcanic mudflow deposits, unit 7 (Southern Mojave Desert) (Tertiary (8-28 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Silurian and/or Ordovician marine rocks, unit 2 (Bishop) (Late Cambrian(?) to Early Permian(?)) at surface, covers < 0.1 % of this area

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

Tertiary volcanic flow rocks, unit 14 (Tranquillon-Obispo) (Tertiary (16-18 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Jurassic marine rocks, unit 6 (Mono Lake) (Ordovician(?) to Triassic(?)) at surface, covers < 0.1 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Paleozoic marine rocks, undivided, unit 5 (Northeastern Sierra Nevada) (Ordovician to Jurassic) at surface, covers < 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Precambrian granitic rocks (?), (Death Valley) (Miocene) at surface, covers < 0.1 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California(?)

Lithology: diorite

Eocene and Paleocene marine rocks, undivided (Paleocene to middle Eocene) at surface, covers < 0.1 % of this area

Franciscan Complex, unit 2 (Southern California) (late Early to early Late Cretaceous) at surface, covers < 0.1 % of this area

Franciscan complex: Cretaceous and Jurassic sandstone with smaller amounts of shale, chert, limestone, and conglomerate. Includes Franciscan melange, except where separated--see KJfm.

Tertiary intrusive rocks (hypabyssal), unit 6 (Southern Mojave Desert) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Tertiary volcanic flow rocks, unit 2 (Pinnacles-Neenach) (Tertiary (22-24 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Quaternary pyroclastic and volcanic mudflow deposits, unit 1 (Cascade Volcanic Field) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Permian marine sedimentary rocks, unit 3 (Northeastern Sierra Nevada) (Early to Late Permian) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Tertiary volcanic flow rocks, unit 13 (Plush Ranch-Vasquez-Diligencia) (Tertiary (19-23 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary pyroclastic and volcanic mudflow deposits, unit 5 (Southern California Basin) (Tertiary (8-25 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Paleozoic metavolcanic rocks, unit 4 (Western Sierra Nevada Foothills) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Lithology: metavolcanic rock

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 1 (Cascade Volcanic Field) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) pyroclastic and volcanic mudflow deposits; in part Pleistocene.

Paleozoic marine rocks, undivided, unit 7 (Southeastern Klamath Mountains) (Devonian(?)) at surface, covers < 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Lithology: gneiss; amphibolite

Cenozoic (Tertiary) granitic rocks, unit 2 (Catalina Island) (early Miocene) at surface, covers < 0.1 % of this area

Cenozoic (Tertiary) granitic rocks--quartz monzonite, quartz latite, and minor monzonite, granodiorite, and granite; found in the Kingston, Panamint, Amargosa, and Greenwater Ranges in southeastern California.

Lithology: quartz diorite

Triassic marine rocks, unit 1 (Death Valley area and Mojave Desert) (Early to Middle Triassic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Tertiary volcanic flow rocks, unit 19 (Lovejoy) (Tertiary (14-16 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: basalt

Carboniferous marine rocks, unit 8 (Mono Lake) (Ordovician to Devonian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Undated granitic rocks, unit 2 (Western Klamath Mountains) (Late Triassic to Early Jurassic) at surface, covers < 0.1 % of this area

Undated granitic rocks unit 2

Permian marine sedimentary rocks, unit 2 (Northwestern Sierra Nevada) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Tertiary volcanic flow rocks, unit 6 (Page Mill-Mindego) (Tertiary (12-15 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: basalt; andesite; dacite

Cretaceous marine rocks (in part nonmarine), unit 2 (West Walker River) (Triassic(?) and/or Jurassic(?)) at surface, covers < 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges

Carboniferous marine rocks, unit 7 (Bishop) (Mississippian to Early Permian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Cenozoic (Tertiary) granitic rocks? (Skidoo Pluton) (Early to Late Cretaceous) at surface, covers < 0.1 % of this area

Cenozoic (Tertiary) granitic rocks--quartz monzonite, quartz latite, and minor monzonite, granodiorite, and granite; found in the Kingston, Panamint, Amargosa, and Greenwater Ranges in southeastern California(?)

Tertiary intrusive rocks (hypabyssal), unit 9 (Jurassic gabbros along Hayward Fault) (Jurassic) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: gabbro

Quaternary pyroclastic and volcanic mudflow deposits, unit 1, questionably identified (Cascade Volcanic Field) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Tertiary volcanic flow rocks, unit 9 (Caliente) (Tertiary (14-18 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: basalt

Paleozoic metavolcanic rocks, unit 5 (Mono Lake) (Triassic to Jurassic) at surface, covers < 0.1 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Tertiary pyroclastic and volcanic mudflow deposits, unit 4 (Tranquillon-Obispo) (Tertiary (16-18 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Quaternary volcanic flow rocks, unit 4 (Sutter Buttes) (Quaternary (1.5-2.5 Ma)) at surface, covers < 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Permian marine sedimentary rocks, unit 4 (Eastern Klamath Mountains) (Early Permian) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Lithology: limestone

Schist of various types and ages, unit 6 (Santa Cruz Mountains) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist; quartzite; marble

Paleozoic marine rocks, undivided, unit 8 (Northeastern Klamath Mountains) (Ordovician(?) to Devonian(?)) at surface, covers < 0.1 % of this area

Undivided Paleozoic metasedimentary rocks. Includes slate, sandstone, shale, chert, conglomerate, limestone, dolomite, marble, phyllite, schist, hornfels, and quartzite

Lithology: mudstone; phyllite

Mesozoic granitic rocks, unit 6 (Eastern Klamath Mountains) (Permian) at surface, covers < 0.1 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite

Lithology: diorite

Recent (Holocene) volcanic flow units, unit 3 (Clear Lake Volcanic Field) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: andesite

Tertiary intrusive rocks (hypabyssal), unit 5 (Southern California Basin) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: basalt; andesite; dacite

Carboniferous marine rocks, unit 6 (Northeastern Sierra Nevada) (Mississippian to Early Permian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Tertiary volcanic flow rocks, unit 12 (Sam Emigdio) (Tertiary (22-25 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary volcanic flow rocks, unit 10 (Alverson) (Tertiary (14-18 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Schist of various types and ages, unit 3 (Santa Cruz Island) (Jurassic) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Schist of various types and ages, unit 9 (Cargo Muchacho Mountains) (Jurassic(?)) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Tertiary volcanic flow rocks, unit 4 (Berkeley Hills) (Tertiary (8-12 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: basalt; dacite; rhyolite

Precambrian granitic rocks, unit 4, (Death Valley) (Miocene) at surface, covers < 0.1 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California

Lithology: diorite

Tertiary volcanic flow rocks, unit 7 (Anderson Reservoir-Coyote) (Tertiary (2.5-3.5 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: trachybasalt

Tertiary volcanic flow rocks, unit 11 (Jacumba) (Tertiary (12-19 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Tertiary pyroclastic and volcanic mudflow deposits, unit 3 (Pinnacles-Neenach) (Tertiary (22-24 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Schist of various types and ages, unit 5 (Slate Range) (Mesozoic) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist; gneiss; slate

Schist of various types and ages, unit 4 (El Paso Mountains) (Paleozoic) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: mica schist; marble

Tertiary intrusive rocks (hypabyssal), unit 2 (Quien Sabe Volcanic Field) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: dacite; andesite; basalt

Paleozoic metavolcanic rocks, unit 6 (El Paso Mountains) (Devonian(?) and Permian) at surface, covers < 0.1 % of this area

Undivided Paleozoic metavolcanic rocks. Mostly flows, breccia and tuff, including greenstone, diabase, and pillow lavas; minor interbedded sedimentary rocks

Lithology: greenstone; andesite

Quaternary volcanic flow rocks, unit 8 (Peninsular Ranges) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Lithology: basalt

Quaternary volcanic flow rocks, unit 7, questionably identified (Mojave Desert) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary volcanic flow rocks; minor pyroclastic deposits; in part Pliocene and Miocene.

Quaternary pyroclastic and volcanic mudflow deposits, unit 5 (Coso Volcanic Field) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Lithology: rhyolite; tuff

Jurassic marine rocks (?), (Lake Beryessa) (Jurassic(?)) at surface, covers < 0.1 % of this area

Lithology: siltstone

Quaternary pyroclastic and volcanic mudflow deposits, unit 4 (Sierra Nevada) (Quaternary) at surface, covers < 0.1 % of this area

Quaternary pyroclastic and volcanic mudflow deposits.

Tertiary intrusive rocks (hypabyssal), unit 4 (Tranquillon-Obispo) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: rhyolite; dacite; basalt

Paleozoic and Permo-Triassic granitic rocks, unit 1 (Eastern Klamath Mountains) (Permian) at surface, covers < 0.1 % of this area

Paleozoic and Permo-Triassic granitic rocks in the San Gabriel and Klamath Mountains

Silurian and/or Ordovician marine rocks, unit 4 (Northern Sierra Nevada) (Ordovician to Devonian) at surface, covers < 0.1 % of this area

Sandstone, shale, conglomerate, chert, slate, quartzite, hornfels, marble, dolomite, phyllite; some greenstone

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

ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits

Mesozoic granitic rocks (?) (Jurassic(?)) at surface, covers < 0.1 % of this area

Mesozoic granite, quartz monzonite, granodiorite, and quartz diorite(?) (Northern Klamath Mountains)

Lithology: diorite

Precambrian granitic rocks, unit 3, (San Gabriel Mountains Granite) (Late Triassic) at surface, covers < 0.1 % of this area

Precambrian granite, syenite, anorthosite, and gabbroic rocks in the San Gabriel Mountains; also various Precambrian plutonic rocks elsewhere in southeastern California

Lithology: granite

Tertiary intrusive rocks (hypabyssal), unit 3 (Pinnacles Volcanic Field) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: rhyolite

Triassic marine rocks, unit 6 (Southern Sierra Nevada) (Late Triassic to Early Jurassic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Miocene marine rocks (?) (Miocene(?) or Pliocene(?)) at surface, covers < 0.1 % of this area

Lithology: sandstone; conglomerate

Upper Cretaceous marine rocks (?) (Cretaceous) at surface, covers < 0.1 % of this area

Upper Cretaceous sandstone, shale, and conglomerate (?)

Cretaceous marine rocks (in part nonmarine) (?), unit 2 (Jacumba) (Late Cretaceous(?) to Miocene(?)) at surface, covers < 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges (?)

Lithology: sandstone; conglomerate

Tertiary pyroclastic and volcanic mudflow deposits, unit 2 (Berkeley Hills) (Tertiary (8-12 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Lithology: basalt; dacite; rhyolite; tuff

Tertiary pyroclastic and volcanic mudflow deposits, unit 6 (Jacumba) (Tertiary (12-19 Ma)) at surface, covers < 0.1 % of this area

Tertiary pyroclastic and volcanic mudflow deposits.

Triassic marine rocks, unit 7 (Mono Lake) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Lithology: hornfels; quartzite; chert

Oigocene nonmarine rocks (?), unit 1 (Klamath Mountains) (Oligocene(?) to Pleistocene(?)) at surface, covers < 0.1 % of this area

Lithology: sand; gravel

Triassic marine rocks, unit 5 (Northern Sierra Nevada) (Middle to Late Triassic) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Basalt (upper and middle Miocene) (Middle to Late Miocene) at surface, covers < 0.1 % of this area

Basalt flows, flow breccia, and basaltic peperite; minor andesite flows; some interbeds of tuff and tuffaceous sedimentary rocks. Basalt is aphyric to moderately porphyritic with phenocrysts of plagioclase and olivine and exhibits both subophitic and diktytaxitic textures. Includes Picture Rock Basalt of Hampton (1964), radiometrically dated by potassium-argon methods as middle(?) and late Miocene in age (see Fiebelkorn and others, 1983), flows of Deer Butte Formation of Kittleman and others (1967), and extensive unnamed flow sequences in the Basin-Range and Owyhee Upland Provinces of southern Lake, Harney, and Malheur Counties that are younger than Steens Basalt, dated at about 15 Ma (Baksi and others, 1967) and the Owyhee Basalt, dated at about 14 Ma (Bottomley and York, 1976; see also Fiebelkorn and others, 1983), and older than 7 or 8 Ma. Partly coeval with the Saddle Mountains Basalt of the Columbia River Basalt Group (Swanson and others, 1979)

Jurassic marine rocks, unit 3 (Mojave Desert) (Jurassic) at surface, covers < 0.1 % of this area

Shale, sandstone, minor conglomerate, chert, slate, limestone; minor pyroclastic rocks

Lower Cretaceous marine rocks (?) (Cretaceous (?)) at surface, covers < 0.1 % of this area

Lower Cretaceous sandstone, shale, and conglomerate (?)

Cretaceous marine rocks (in part nonmarine), unit 3 (Mescal Range) (Middle Jurassic to late Early Cretaceous) at surface, covers < 0.1 % of this area

Undivided Cretaceous sandstone, shale, and conglomerate; minor nonmarine rocks in Peninsular Ranges

Carboniferous marine rocks, unit 5 (Northwestern Sierra Nevada) (Paleozoic or Mesozoic) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate, limestone, dolomite, chert, hornfels, marble, quartzite; in part pyroclastic rocks

Lithology: quartzite; chert

Playa, marsh, and alluvial-flat deposits, locally eroded (Quaternary) at surface, covers < 0.1 % of this area

PLAYA, MARSH, AND ALLUVIAL-FLAT DEPOSITS, LOCALLY ERODED

Lithology: playa; alluvium

Open Water (Holocene) at surface, covers < 0.1 % of this area

water

Lithology: water

Metamorphic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

METAMORPHIC ROCKS-Gneiss and schist and lesser amounts of gneissic granite, pyroxenite, hornblendite, migmatite, pegmatite, and marble.

Tertiary volcanic flow rocks, unit 5 (San Luis Reservoir) (Tertiary (7.5-9.5 Ma)) at surface, covers < 0.1 % of this area

Tertiary volcanic flow rocks; minor pyroclastic deposits.

Lithology: basalt; andesite

Triassic marine rocks, unit 4 (West Walker River) (Triassic(?)) at surface, covers < 0.1 % of this area

Shale, conglomerate, limestone and dolomite, sandstone, slate, hornfels, quartzite; minor pyroclastic rocks

Lacustrine and fluvial sedimentary rocks (Pleistocene) (Pleistocene) at surface, covers < 0.1 % of this area

Unconsolidated to semiconsolidated lacustrine clay, silt, sand, and gravel; in places includes mudflow and fluvial deposits and discontinuous layers of peat. Includes older alluvium and related deposits of Piper (1942), Willamette Silt (Allison, 1953; Wells and Peck, 1961), alluvial silt, sand, and gravel that form terrace deposits of Wells and others (1983), and Gresham and Estacada Formations of Trimble (1963). Includes deltaic gravel and sand and gravel bars, in pluvial lake basins in southeastern part of map area. In Rome Basin, includes discontinuous layers of poorly consolidated conglomerate characterized by well-rounded, commonly polished pebbles of chert and pebbles and cobbles of quartzite. In places contains mollusks or vertebrate fossils indicating Pleistocene age; mostly deposits of late Pleistocene age, but locally includes some deposits of early Holocene age. Includes Touchet Beds of Flint (1938), deposits of valley terraces of Newcomb (1965), and, in southeast Oregon, basin-filling deposits that incorporate Mazama ash deposits (Qma, Qmp) in the youngest layers

Lithology: clay or mud; silt; sand; gravel

Basalt and basaltic andesite (Pleistocene and Pliocene) (Pliocene to Pleistocene) at surface, covers < 0.1 % of this area

Flows, flow breccia, and pyroclastic deposits. Flows are aphanitic to finely crystalline, commonly diktytaxitic, and aphyric to porphyritic. Textures are mostly intergranular grading to intersertal; some andesite flows are finely trachytic and a few basalt flows are subophitic. Phenocrysts, mostly unaltered, include bytownite and labradorite, olivine, calcic augite, and hypersthene. Flows and breccia form shields, lava cones, and valley fill; in places greatly dissected and modified by fluvial erosion. Includes Boring Lava of Trimble (1963) and Hampton (1972) and Battle Ax Basalts of Thayer (1936). Potassium-argon ages from this unit range from about 1.2 to 3.9 Ma; in places difficult to distinguish from youngest flows of unit Trb

Lithology: basalt; andesite

Middle Miocene to Oligocene volcanic and sedimentary rocks, undivided (Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

Sequences of diverse volcanic rocks with abundant interbedded sedimentary rocks. (11-32 Ma)

Granitic rocks (Cretaceous) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Miocene marine rocks and Franciscan schist (Cretaceous(?) to Miocene) at surface, covers < 0.1 % of this area

Schist of various types and ages, unit 11 (Benton Range) (Late Proterozoic(?) to Paleozoic(?)) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist; hornfels

Andesite and basalt flows (Early Miocene to Early Pliocene) at surface, covers < 0.1 % of this area

ANDESITE AND BASALT FLOWS-Mostly in about 17 to about 6 m.y. age range. In Humboldt County, locally includes rocks as old as 21 m.y. May include rocks younger than 6 m.y. in places

Lithology: basalt; andesite; shoshonite

Oligocene nonmarine rocks (?), unit 2 (Southeastern California) (Cretaceous(?) to Oligocene(?)) at surface, covers < 0.1 % of this area

Ultramafic and related rocks of ophiolite sequences (Jurassic) (Paleozoic(?), Triassic(?), and Jurassic) at surface, covers < 0.1 % of this area

Predominantly harzburgite and dunite with both cumulate and tectonite fabrics. Locally altered to serpentinite. Includes gabbroic rocks and sheeted diabasic dike complexes. Comprises Josephine ophiolite of Harper (1980), ophiolites of Onion Mountain, Sexton Mountain, Pearsoll Peak, Rogue River, and Riddle areas (Smith and others, 1982) and Coast Range ophiolite and serpentinite melange of M.C. Blake, Jr. and A.S. Jayko (unpublished data, 1985). In southwest Oregon, locally includes small bodies of early Mesozoic or late Paleozoic serpentinized and sheared ultramafic rocks, mostly in shear zones. Locally, volcanic and sedimentary rocks shown separately

Landslide and debris-flow deposits (Holocene and Pleistocene) (Pleistocene to Holocene) at surface, covers < 0.1 % of this area

Unstratified mixtures of fragments of adjacent bedrock. Locally includes slope wash and colluvium. Largest slides and debris flows occur where thick sections of basalt and andesite flows overlie clayey tuffaceous rocks. May include some deposits of late Pliocene age

Lithology: landslide

Recent (Holocene) volcanic flow units, unit 5 (Salton Sea) (Holocene) at surface, covers < 0.1 % of this area

Recent (Holocene) volcanic flow rocks; minor pyroclastic deposits; in part Pleistocene.

Lithology: rhyolite

Basalt flows (Late Miocene to Middle Miocene) at surface, covers < 0.1 % of this area

BASALT FLOWS

Lithology: basalt

Andesite and related rocks of intermediate composition (Late Miocene to Middle Miocene) at surface, covers < 0.1 % of this area

ANDESITE AND RELATED ROCKS OF INTERMEDIATE COMPOSITION-Flows and breccias

Quaternary surficial deposits, undivided (Quaternary) at surface, covers < 0.1 % of this area

Unconsolidated to strongly consolidated alluvial and eolian deposits. This unit includes: coarse, poorly sorted alluvial fan and terrace deposits on middle and upper piedmonts and along large drainages; sand, silt and clay on alluvial plains and playas; and wind-blown sand deposits. (0-2 Ma)

Lithology: sand; gravel; mud; silt

Shale, sandstone, volcanogenic clastic rocks, andesite, rhyolite, and locally thick carbonate units (Late Triassic to Early Cretaceous) at surface, covers < 0.1 % of this area

SHALE, SANDSTONE, VOLCANOGENIC CLASTIC ROCKS, ANDESITE, RHYOLITE, AND LOCALLY THICK CARBONATE UNITS-Undivided sequence locally containing recognizable equivalents of the Luning and Dunlap Formations

Limestone and sparse dolomite, siltstone, and sandstone (Mississippian to Early Permian) at surface, covers < 0.1 % of this area

LIMESTONE AND SPARSE DOLOMITE, SILTSTONE, AND SANDSTONE-Includes units such as undivided Riepe Spring Limestone of Steele (1960) and Ely Limestone or their equivalent in Elko, White Pine, and northern Lincoln Counties and most of the Bird Spring Formation and Callville Limestone in Clark and southern Lincoln Counties. Includes some stratigraphically higher Permian rocks in Leppy Peak, easternmost Elko County.

Melange of Dutchmans Peak (Triassic or Paleozoic) (Paleozoic(?) to Jurassic(?)) at surface, covers < 0.1 % of this area

Heterogeneous mixture of interlayered metasedimentary and metavolcanic rocks metamorphosed to upper greenschist and (or) almandine-amphibolite facies, and serpentinite, gabbro, and metagabbro (Smith and others, 1982)

Olivine basalt (Pliocene and Miocene) (Miocene to Pliocene) at surface, covers < 0.1 % of this area

Thin, commonly open-textured (diktytaxitic), subophitic to intergranular olivine basalt flows, intercalated with and grades laterally through palagonite breccia and tuff into tuffaceous sedimentary rocks (unit Ts). In places includes flows of platy olivine andesite or basaltic andesite. Several potassium-argon ages ranging from about 4 to 7 Ma indicate unit is mostly of early Pliocene and late Miocene age. Includes Shumuray Ranch Basalt and Antelope Flat Basalt of Kittleman and others (1965), Grassy Mountain Basalt of Corcoran and others (1962), Drinkwater Basalt of Bowen and others (1963), basalt formerly assigned to Danforth Formation by Piper and others (1939) (see Walker, 1979), Hayes Butte Basalt of Hampton (1964), Pliocene and upper Miocene basalt flows capping and interstratified with the Madras (or Deschutes) Formation, and basalt flows interstratified in the Dalles Formation of Newcomb (1966; 1969)

Lithology: basalt; andesite

Schist of various types and ages, unit 10 (Halloran Complex) (Precambrian) at surface, covers < 0.1 % of this area

Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.

Lithology: schist

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

Sand, gravel, and silt forming flood plains and filling channels of present streams. In places includes talus and slope wash. Locally includes soils containing abundant organic material, and thin peat beds

Lithology: sand; gravel; silt; peat

Tertiary intrusive rocks (hypabyssal), unit 8 (Crescent City) (Tertiary) at surface, covers < 0.1 % of this area

Tertiary intrusive rocks; mostly shallow (hypabyssal) plugs and dikes. Includes some Mesozoic rocks.

Lithology: dacite

Granitic rocks (Jurassic) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Mostly quartz monzonite and granodiorite

Granitic rocks (Cretaceous and Jurassic) (Late Jurassic and Early Cretaceous) at surface, covers < 0.1 % of this area

Mostly tonalite and quartz diorite but including lesser amounts of other granitoid rocks. Potassium-argon ages determined on hornblende indicates plutons range in age from 143 to 166 Ma (Hotz, 1971)

Basalt flows (Miocene to Quaternary) at surface, covers < 0.1 % of this area

BASALT FLOWS-Locally includes maar deposits

Clastic sedimentary rocks (Upper and Lower Cretaceous) (Early to Late Cretaceous) at surface, covers < 0.1 % of this area

Locally fossiliferous sandstone and conglomerate; marine fossils indicate Early Cretaceous (Albian) age (Jones, 1960). Includes the Hornbrook Formation of Peck and others (1956), the Grove Creek strata of Jones (1960) and Page and others (1977), Hunters Cove Formation, Cape Sebastian Sandstone, Humbug Mountain Conglomerate, and Rocky Point Formation (Dott, 1971; Blake and others, 1985) and clastic sedimentary rocks on the West Fork of the Illinois River near Waldo (Imlay and others, 1959), about 12 km south of Cave Junction

Early Tertiary to Late Cretaceous granitic rocks (Late Cretaceous to Early Tertiary) at surface, covers < 0.1 % of this area

Porphyritic to equigranular granite to diorite emplaced during the Laramide orogeny. Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks of this unit, and are thus named 'porphyry copper deposits'. (50-82 Ma)

Intrusive rocks (Late Cretaceous to Middle Miocene) at surface, covers < 0.1 % of this area

INTRUSIVE ROCKS-Aphanitic, porphyritic, and coarsely granular rocks ranging in composition from diorite to granite. Clark County

Granitic rocks, western Nevada (Jurassic to Cretaceous) at surface, covers < 0.1 % of this area

GRANITIC ROCKS, WESTERN NEVADA (Mesozoic)-Mostly quartz monzonite and granodiorite. Inconclusively dated or not dated radiometrically

Andesite and dacite and sedimentary rocks (Miocene? and Oligocene) (Oligocene to Miocene) at surface, covers < 0.1 % of this area

Lava flows, breccia, volcaniclastic and epiclastic rocks mostly of andesitic and dacitic composition; includes minor amounts of altered basaltic rocks. Joint surfaces and cavities commonly lined with hematite or montmorillonite clay, secondary silica minerals, zeolites, celadonite, or calcite. Andesite and dacite typically have plagioclase, hornblende, and clinopyroxene phenocrysts; some flows aphyric. Platy flow-jointing common. Age, mostly Oligocene; may include some rocks of early Miocene age. As shown, may include some rocks older than Oligocene, correlative with upper parts of unit Tea. One potassium-argon age of about 28 Ma on porphyritic hornblende andesite from Sheep Creek, southwest corner of Union County, indicates in part coeval with unit Tsf

Lithology: andesite; dacite; clastic

Intrusive rocks of mafic and intermediate composition (Miocene to Quaternary) at surface, covers < 0.1 % of this area

INTRUSIVE ROCKS OF MAFIC AND INTERMEDIATE COMPOSITION

Quartzite and minor amounts of conglomerate, phyllitic siltstone, limestone, and dolomite (Late Proterozoic to Early Cambrian) at surface, covers < 0.1 % of this area

QUARTZITE AND MINOR AMOUNTS OF CONGLOMERATE, PHYLLITIC SILTSTONE, LIMESTONE, AND DOLOMITE-Includes Prospect Mountain Quartzite, Osgood Mountain Quartzite, and Gold Hill Formation in northern Nevada, and Stirling Quartzite, Wood Canyon Formation, and Zabriskie Quartzite in southern Nevada.

Welded and nonwelded silicic ash-flow tuffs (Middle Miocene to Late Miocene) at surface, covers < 0.1 % of this area

WELDED AND NONWELDED SILICIC ASH-FLOW TUFFS-Locally includes thin units of air-fall tuff and sedimentary rock

Lithology: rhyolite

Granitic rocks (Middle Proterozoic) at surface, covers < 0.1 % of this area

GRANITIC ROCKS-Porphyritic rapakivi granite.

Lithology: granite

Orocopia Schist (Late Cretaceous to Early Tertiary) at surface, covers < 0.1 % of this area

Mostly gray, fine-grained quartz-feldspar-mica schist, with sparse metabasalt and metachert. The unit is exposed in tectonic windows in the southwestern corner of Arizona. It is interpreted as metamorphosed marine sandstone that was tectonically emplaced beneath southwestern Arizona during early Tertiary subduction of Pacific Ocean sea floor. (65-165 Ma)

Tuffaceous sedimentary rocks (Late Eocene to Late Miocene) at surface, covers < 0.1 % of this area

TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

Limestone and minor amounts of dolomite and shale (Mississippian) at surface, covers < 0.1 % of this area

LIMESTONE AND MINOR AMOUNTS OF DOLOMITE AND SHALE-Includes units such as Rogers Spring and Monte Cristo Limestones

Rhyolitic flows and shallow intrusive rocks (Middle Miocene to Late Miocene) at surface, covers < 0.1 % of this area

RHYOLITIC FLOWS AND SHALLOW INTRUSIVE ROCKS

Lithology: rhyolite; dacite; trachyte

Condrey Mountain Schist (Triassic? and Paleozoic?) (Paleozoic(?) to Jurassic) at surface, covers < 0.1 % of this area

Consists of a variety of schistose rocks characterized by different proportions of muscovite, quartz, graphite, chlorite, actinolite, and epidote, rare thin layers of metachert, and clinozoisite-actinolite-albite-garnet metagabbro. Potassium-argon age on muscovite from unit is about 141 Ma (Lanphere and others, 1968) and on a whole rock sample is about 155 Ma (Suppe and Armstrong, 1972), indicating a Late Jurassic metamorphic age. Protolith is probably Triassic and Paleozoic in age

Lithology: schist; chert; greenstone

Granite and diorite (Jurassic and Triassic) (Triassic and Jurassic) at surface, covers < 0.1 % of this area

Felsic to intermediate, granitoid intrusive rocks. Includes Jurassic muscovite granodiorite, hornblende gabbro, tonalite, and quartz diorite of southwest Oregon (Smith and others, 1982)

Pyroclastic ejecta of basaltic and andesitic cinder cones (Holocene, Pleistocene, Pliocene, and Miocene?) (Miocene to Holocene) at surface, covers < 0.1 % of this area

Mostly unconsolidated, oxidized, fine to coarse, scoriaceous cinders, bombs, and agglutinate deposited in subaerial environment

Lithology: basalt; andesite

Wyman Formation (Late Proterozoic) at surface, covers < 0.1 % of this area

WYMAN FORMATION-Phyllite and phyllitic siltstone and minor amounts of limestone, dolomite, and sandstone

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

MORAINAL DEPOSITS

Lithology: glacial drift

Middle Proterozoic granitic rocks (Middle Proterozoic) at surface, covers < 0.1 % of this area

Mostly porphyritic biotite granite with large microcline phenocrysts, with local fine-grained border phases and aplite. Associated pegmatite and quartz veins are rare. This unit forms large plutons, including the Oracle Granite, Ruin Granite, granite in the Pinnacle Peak - Carefree area northeast of Phoenix, and several bodies west of Prescott. (1400-1450 Ma)

Older alluvial deposits (Miocene to Quaternary) at surface, covers < 0.1 % of this area

OLDER ALLUVIAL DEPOSITS

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

Massive quartz-feldspar porphyry, generally interpreted as thick, welded rhyolitic tuffs, with locally abundant lava, and sandstone and conglomerate derived from volcanic rocks. Rare eolian quartzite units are interbedded in southern Arizona. Includes Ali Molina Formation, Mount Wrightson Formation, part of the Canelo Hills Volcanics, Cobre Ridge tuff, Black Rock volcanics, Planet Volcanics, and equivalent rocks. (160-200 Ma)

Ridge-capping basalt and basaltic andesite (Pliocene and upper Miocene) (Late Miocene to Pliocene) at surface, covers < 0.1 % of this area

Flows and flow breccia of basaltic andesite and lesser diktytaxitic to intergranular olivine basalt. Includes some dense, aphyric flows, commonly with either cryptocrystalline or pilotaxitic to trachytic texture, and porphyritic flows with phenocrysts and glomerocrysts of olivine, hypersthene, and labradorite. A few flows contain both hypersthene and calcic augite phenocrysts. Olivine mostly fresh or slightly altered to iddingsite in flows high in section; flows low in section show some alteration to clays (nontronite and saponite), secondary silica minerals, and calcite; pinkish-brown glass in some flows unaltered. Locally includes some andesite and dacite. Some flows of this unit are lithologically similar to flow rocks of the High Cascade volcanic sequence and some are more like flows that in the past have been mapped as part of the Sardine Formation (Peck and others, 1964) and Elk Lake Formation of McBirney and others (1974) and Sutter (1978). Potassium-argon ages of rocks from this unit range from about 4 to 8 or 9 Ma. Includes some rocks formerly mapped as Rhododendron Formation by Peck and others (1964)

Middle Miocene to Oligocene sedimentary rocks (Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

Con-glomerate, sandstone, mudstone, limestone, and rock-avalanche breccia (sheet-like deposits of crushed rock) deposited and tilted during widespread normal faulting and basin development. Sediments, mostly conglomerate and sandstone, are commonly medium to dark brown, reddish brown, or brownish gray; younger strata are generally lighter colors. Most deposits are 20 to 30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona. (11-32 Ma)

Phyllitc siltstone, quartzite, and lesser amounts of limestone and dolomite (Late Proterozoic to Early Cambrian) at surface, covers < 0.1 % of this area

PHYLLITIC SILTSTONE, QUARTZITE, AND LESSER AMOUNTS OF LIMESTONE AND DOLOMITE-Includes Reed Dolomite; Deep Spring, Campito, Poleta, Harkless, and Saline Valley Formations; and Mule Spring Limestone

Pliocene to middle Miocene deposits (Middle Miocene to Pliocene) at surface, covers < 0.1 % of this area

Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. These deposits are generally light gray or tan. They commonly form high rounded hills and ridges in modern basins, and locally form prominent bluffs. Deposits of this unit are widely exposed in the dissected basins of southeastern and central Arizona. (2-16 Ma)

Jurassic granitic rocks (Jurassic) at surface, covers < 0.1 % of this area

Granite to diorite, locally foliated and locally alkalic; includes Triassic(?) granitoids in the Trigo Mountains. This unit includes two dominant assemblages of igneous rocks. The Kitt Peak-Trigo Peaks superunit includes, from oldest to youngest: dark, foliated or gneissic diorite, medium-grained equigranular to porphyritic granodiorite, and small, irregular intrusions of light-colored, fine-grained granite. The Ko Vaya superunit, limited to south-central Arizona, includes texturally heterogeneous K-feldspar-rich granitic rocks. (150-180 Ma)

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

LANDSLIDE DEPOSITS

Shale, mudstone, and sandstone (Jurassic) (Late Jurassic) at surface, covers < 0.1 % of this area

Black to gray shale, mudstone, and sandstone with local lenses of pebble conglomerate. Overlies Josephine ophiolite of Harper (1980) (unit Ju)

Limestone and dolomite, locally thick sequences of shale and siltstone (Late Cambrian to Middle Cambrian) at surface, covers < 0.1 % of this area

LIMESTONE AND DOLOMITE, LOCALLY THICK SEQUENCES OF SHALE AND SILTSTONE-Includes units such as Pioche Shale, Eldorado Dolomite, Geddes Limestone, Secret Canyon Shale, Hamburg Dolomite, Dunderberg Shale, and Windfall Formation of northern Nevada and Carrara, Bonanza King, and Nopah Formations of southern Nevada.

Rhyolite and dacite (Pliocene? and Miocene) (Miocene to Pliocene) at surface, covers < 0.1 % of this area

Ash-flow tuff, lava flows, pumice-lapilli tuff, coarse pumicite, flow breccia, and domal complexes of rhyolitic, rhyodacitic, and dacitic composition; in places includes peralkaline rhyolite and some andesite and andesite breccia. Locally porphyritic with phenocrysts of alkali feldspar, plagioclase, and minor augite, ferro-hedenbergite, hornblende, hypersthene, or biotite. Commonly flow banded; locally glassy. Many of the ash--flow tuffs exhibit flow features and only obscure vitro-clastic textures. In places includes interlayers of silicic volcaniclastic rocks and tuffaceous sedimentary rocks. Includes rhyolite at Owyhee Dam, Jump Creek Rhyolite, and Littlefield Rhyolite, all of Kittleman and others (1965); Dooley Rhyolite Breccia of Gilluly (1937), radiometrically dated at 14.7 +/- 0.4 Ma by potassium-argon methods (Fiebelkorn and others, 1983); resurgent domal masses in McDermitt caldera area; and extensive unnamed flows and ash-flow tuffs in the central and southern part of the Owyhee Upland. Also includes isolated masses of dacitic and rhyodacitic flows, breccia, and ash-flow tuff along eastern slope of Cascade Range that are lapped by flows and sediments of the Madras (or Deschutes) Formation. Potassium-argon ages on rocks in unit from southeast Oregon range from about 13 to 16 Ma; lenses of interbedded tuffaceous sedimentary rocks locally contain a Miocene (Barstovian) vertebrate fauna

Lithology: rhyolite; dacite; andesite

Ash-flow tuffs and tuffaceous sedimentary rocks (Middle Miocene to Late Miocene) at surface, covers < 0.1 % of this area

ASH-FLOW TUFFS AND TUFFACEOUS SEDIMENTARY ROCKS

Limestone, dolomite, shale, and quartzite (Ordovician) at surface, covers < 0.1 % of this area

LIMESTONE, DOLOMITE, SHALE, AND QUARTZITE-Includes units such as Pogonip Group, Eureka Quartzite, and Ely Springs Dolomite. Where Ely Springs Dolomite or equivalent rocks are included in SOc unit, this unit includes only the Pogonip Group and Eureka Quartzite or their equivalents.

Volcanic rocks of the Dothan Formation and related rocks (Lower Cretaceous and Upper Jurassic) (Late Jurassic to Early Cretaceous) at surface, covers < 0.1 % of this area

Basaltic pillow lavas, volcanic breccia, and silicified basalt lava flows

Lithology: basalt

Basaltic lava flows (Oligocene to Miocene) at surface, covers < 0.1 % of this area

Basaltic and basaltic andesite lava flows and breccia; grades laterally into rare bedded palagonitic tuff and breccia

Tuffaceous sedimentary rocks and tuff (Pliocene and Miocene) (Miocene to Pliocene) at surface, covers < 0.1 % of this area

Semiconsolidated to well-consolidated mostly lacustrine tuffaceous sandstone, siltstone, mudstone, concretionary claystone, conglomerate, pumicite, diatomite, air-fall and water-deposited vitric ash, palagonitic tuff and tuff breccia, and fluvial sandstone and conglomerate. Palagonitic tuff and breccia grade laterally into altered and unaltered basalt flows of unit Tob. In places includes layers of fluvial conglomerate and, in parts of the Deschutes-Umatilla Plateau, extensive deposits of fanglomerate composed mostly of Miocene basalt debris and silt. Also includes thin, welded and nonwelded ash-flow tuffs. Vertebrate and plant fossils indicate rocks of unit are mostly of Clarendonian and Hemphillian (late Miocene and Pliocene) age. Potassium-argon ages on interbedded basalt flows and ash-flow tuffs range from about 4 to 10 Ma. Includes the Drewsey Formation of Shotwell and others (1963); sedimentary parts of the Rattlesnake Formation of Brown and Thayer (1966); an interstratified ash-flow tuff has been radiometrically dated by potassium-argon methods at about 6.6 Ma (see Fiebelkorn and others, 1983); Bully Creek Formation of Kittleman and others (1967); Dalles Formation of Newcomb (1966, 1969); Shutler Formation of Hodge (1932), McKay beds of Hogenson (1964) and Newcomb (1966) (see also Shotwell, 1956); Kern Basin Formation of Corcoran and others (1962); Rome beds of Baldwin (1976); parts of the (now obsolete) Danforth Formation of Piper and others (1939), Idaho Group of Malde and Powers (1962), Thousand Creek Beds of Merriam (1910); the Madras (or Deschutes) Formation, the "Simtustus formation" of Smith (1984), and the Yonna Formation (Newcomb, 1958). In areas west of Cascade crest, includes the Sandy River Mudstone and the Troutdale Formation of Trimble (1963) and the lower Pliocene Helvetia Formation of Schlicker and Deacon (1967)

Holocene river alluvium (Holocene) at surface, covers < 0.1 % of this area

Unconsolidated to weakly consolidated sand and gravel in river channels and sand, silt, and clay on floodplains. Also includes young terrace deposits fringing floodplains. (0-10 ka)

Lithology: sand; gravel; mud; silt

Rhyolitic tuff, tuffaceous sedimentary rocks, and lava flows (lower Miocene, Oligocene, and uppermost Eocene?) (Late Eocene to Early Miocene) at surface, covers < 0.1 % of this area

Rhyolitic to dacitic varicolored bedded tuff, lapilli tuff, and fine- to medium-grained tuffaceous sedimentary rocks with interstratified welded and nonwelded ash-flow tuff and interbedded basalt and andesite flows. Also includes minor rhyolite and dacite flows and domes. Glass in tuff and tuffaceous sedimentary rocks is commonly altered to zeolites, clay minerals, and small amounts of opal, chalcedony, orthoclase, and calcite. Fossil plants and vertebrates indicate an Oligocene and Miocene age. Locally a late Hemingfordian age indicated by mammalian fauna (Woodburn and Robinson, 1977). May include some rocks of middle Miocene age in the area west and northwest of Lakeview. Potassium-argon ages on rocks from unit range from about 36 Ma (Swanson and Robinson, 1968) to about 20 Ma. Includes Pike Creek Formation of Walker and Repenning (1965), originally identified as Pike Creek Volcanic Series by Fuller (1931), and unnamed volcanic and volcaniclastic rocks of southern Lake County, some of which have been correlated with the Miocene and Oligocene Cedarville Formation of northeastern California

Lithology: tuff; basalt; andesite

Middle Miocene to Oligocene volcanic rocks (Oligocene to Middle Miocene) at surface, covers < 0.1 % of this area

Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)

Early Proterozoic granitic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

Wide variety of granitic rocks, including granite, granodiorite, tonalite, quartz diorite, diorite, and gabbro. These rocks commonly are characterized by steep, northeast-striking foliation. (1600-1800 Ma)

Mafic and intermediate vent rocks (Pliocene? and Miocene) (Miocene to Pliocene) at surface, covers < 0.1 % of this area

Basaltic and andesitic agglomerate, breccia, scoria, cinders, flows, and intrusive masses forming lava cones and small shields

Lithology: basalt; andesite

Melange (Jurassic) (Jurassic) at surface, covers < 0.1 % of this area

Structurally complex mixture of basaltic rocks, serpentinite, chert, argillite, conglomerate, silty sandstone, and lenses of marble composing the melange of the Takilma area of Smith and others (1982)

Shale, siltstone, sandstone, chert-pebble conglomerate, and limestone (Devonian to Mississippian) at surface, covers < 0.1 % of this area

SHALE, SILTSTONE, SANDSTONE, CHERT-PEBBLE CONGLOMERATE, AND LIMESTONE-Includes units such as Pilot Shale, Joana Limestone, Chainman Shale, and Diamond Peak Formation in northern and eastern Nevada and Narrow Canyon Limestone, Mercury Limestone, and Eleana Formation in southern Nevada

Mafic vent complexes (Miocene) (Miocene) at surface, covers < 0.1 % of this area

Intrusive plugs and dike swarms and related near-vent flows, breccias, cinders, and agglutinate of basaltic andesite, basalt, and andesite; commonly in the form of eroded piles of red, iron-stained thin flows, cinders, and agglutinate cut by mafic intrusions

Silicic vent rocks (Pliocene, Miocene, Oligocene, and Eocene?) (Eocene to Pliocene) at surface, covers < 0.1 % of this area

Plugs and domal complexes of rhyolitic, rhyodacitic, and dacitic composition; includes related near-vent flows, flow breccia, and deposits of obsidian, perlite, and pumice. Locally includes resurgent domes related to caldera complexes. In southeast Oregon many domal complexes younger than 11 Ma exhibit a well-defined southeast to northwest age progression (Walker, 1974; MacLeod and others, 1976) from about 11 Ma to less than 1 Ma

Lithology: rhyolite; latite; dacite

Breccia (Middle Eocene to Early Pliocene) at surface, covers < 0.1 % of this area

BRECCIA-Volcanic, thrust, and jasperoid breccia and landslide megabreccia

Tuffaceous sedimentary rocks (Early Oligocene to Early Miocene) at surface, covers < 0.1 % of this area

TUFFACEOUS SEDIMENTARY ROCKS-Locally includes minor amounts of tuff

Early Proterozoic metamorphic rocks (Early Proterozoic) at surface, covers < 0.1 % of this area

Undivided metasedimentary, metavolcanic, and gneissic rocks. (1600-1800 Ma)