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Geologic units containing mudflow

California

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 1 (Cascade Volcanic Field) (Holocene)

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

Recent (Holocene) pyroclastic and volcanic mudflow deposits, unit 2 (Mono Craters) (Holocene)

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

Oregon

Lacustrine and fluvial deposits (Miocene) (Miocene)

Poorly to moderately consolidated, bedded silicic ash and pumicite, diatomite, tuffaceous sedimentary rocks, minor mudflow deposits, and some coarse epiclastic deposits. Vitroclastic material in some beds diagenetically altered to zeolites, secondary silica minerals, and clay minerals. In eastern Blue Mountains province vertebrate fossils indicate unit is mostly of late Miocene (Clarendonian) age, but may also include some rocks of middle Miocene (Barstovian) age. In High Lava Plains and northern Owyhee Upland provinces, vertebrate fossils indicate unit is partly late Miocene (Clarendonian), but probably is mostly middle Miocene (Barstovian) in age. Interfingers and grades laterally into unit Tmb. Includes lake and stream sediments and tuffaceous lake and stream deposits of Prostka (1962, 1967), Deer Butte Formation of Corcoran and others (1962) and Kittleman and others (1967), Juntura Formation of Shotwell and others (1963), some rocks originally assigned to the lower part of the (now obsolete) Danforth Formation of Piper and others (1939), and interbeds in upper part of Columbia River Basalt Group in northern Wallowa County

Washington

Eocene-Oligocene volcanic rocks (Eocene-Oligocene)

Predominantly light-green, bedded andesite breccia with interbedded andesite and basalt flows, mudflows, and tuff beds; becomes more tuffaceous near top of unit. Includes tuffaceous and arkosic sandstone, shale, and carbonaceous shale beds in central and southern Cascade Mountians. Rhyodacite and quartz latite flows in northwestern Ferry County.

Older glacial drift (Pleistocene)

Till, outwash, and associated interglacial deposits; sorted and unsorted gravel, sand, silt, and clay. Includes peat beds and non-glacial sediments locally. Mostly pre-Wisconsin in age.