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Eocene nonmarine rocks

Predominantly sandstone and shale. Includes some conglomerate in the Cle Elum area in Kittilas County. Contains extensive coal seams near Roslyn and carbonaceous shale and coal beds in White Pass area. Contains tuff beds in northwestern Ferry County.
State Washington
Name Eocene nonmarine rocks
Geologic age Eocene
Comments Naches Formation is mostly basaltic and rhyolitic volcanic rock with minor andesitic rock and interbedded sedimentary rock (feldspathic sandstone) (Tabor and others, 1993, Stout, 1964). The thickness of the Naches Formation is 8000-10000+ feet thick (Stout, 1964).
Primary rock type arkose
Secondary rock type siltstone
Other rock types basalt; rhyolite; andesite; argillite; tuff; shale; conglomerate; coal
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone > Arkose (Bed)
Minor
Sedimentary > Clastic > Siltstone (Bed)
Igneous > Volcanic > Mafic-volcanic > Basalt
Igneous > Volcanic > Felsic-volcanic > Rhyolite
Incidental
Metamorphic > Argillite
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Conglomerate (Bed)
Sedimentary > Coal > Bituminous (Bed)
Igneous > Volcanic > Mafic-volcanic > Andesite
Igneous > Volcanic (Pyroclastic, tuff)
Map references
Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.
Unit references
Huntting, M. T., Bennett, W. A. G., Livingston, V. E. Jr., Moen, W. S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.
Muessig, S., 1967, Geology of the Republic Quadrangle and a Part of the Aeneas Quadrangle, Ferry County, Washington: U. S. Geological Survey Bulletin 1216, 135 p.
Foster, R. J., 1960, Tertiary Geology of a Portion of the Central Cascade Mountains, Washington: Geological Society of America Bulletin v. 71, no. 2, p. 99-126.
Tabor, R. W., Frizzell, V. A., Jr., Booth, D. B., Waitt, R. B., Whetten, J. T., Zartman, R. E., 1993, Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1963, scale 1:100,000.
Tabor, R. W., Waitt, R. B., Jr., Frizzell, V. A., Jr., Swanson, D. A., Byerly, G. R., Bentley, R. D., 1982, Geologic Map of the Wanatchee 1:100,000 Quadrangle, Central Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1311, scale 1:100,000.
Stout, M. L., 1964, Geology of a Part of the South-Central Cascade Mountains, Washington: Geological Society of America Bulletin, v. 75, no. 4, p 317-334.
Counties Ferry - King - Kittitas - Lewis - Skamania - Yakima