Paleocene-Cretaceous nonmarine rocks

Brown-gray to light-gray, medium- to course-grained massive cross-bedded arkose with interbedded conglomerate and siltstone. Contains several coal seams in Whatcom County. Iron-rich laterite at base near Cle Elum and Blewett Pass in Kittitas and Chelan Counties.
State Washington
Name Paleocene-Cretaceous nonmarine rocks
Geologic age Eocene (see age coding)
Lithologic constituents
Sedimentary > Clastic > Sandstone > Arkose (Bed)Also includes minor tuffaceous sandstone.
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Conglomerate (Bed, Lens)
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Coal (Bed)
Igneous > Volcanic (Pyroclastic-tuff)
Comments Two polygons on the digital coverage are tagged as TKc (the original name of this unit). Chumstick formation is usually referred to as Swauk formation but is younger in age (middle Eocene as opposed to early Eocene) (Tabor and others, 1987).
Stratigraphic units Chuckanut Formation; Guye Formation; Pipestone Canyon Formation; Swauk Formation; Chumstick formation

Huntting, M.T., Bennett, W.A.G., Livingston, V.E.Jr., and Moen, W.S., 1961, Geologic Map of Washington: Washington Division of Mines and Geology, scale 1:500,000.

Easterbrook, D.J., 1976b, Geologic Map of Western Whatcom County, Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-854-B, scale 1:62,500.

Misch, P., 1977, Bedrock Geology of the North Cascades, in Brown, E. H. and Ellis, R. C. (eds.), Geological Excursions in the Pacific Northwest, Geological Society of America 1977 Annual Meeting, Seattle: Western Washington University, p. 1-62.

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.

Barksdale, J.D., 1975, Geology of the Methow Valley, Okanogan County, Washington: Washington Division of Geology and Earth Resources Bulletin no. 48, 72 p.

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., Frizzell, V.A.,Jr., Whetten, J.T., Waitt, R.B., Swanson, D.A., Byerly, G.R., Booth, D.B., Hetherington, M.J., Zartman, R.E., 1987, Geologic Map of the Chelan 30-Minute by 60-Minute Quadrangle, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1661, scale 1:100,000.

NGMDB product
Counties Chelan - Douglas - King - Kittitas - Okanogan - Skagit - Snohomish - Whatcom