Quaternary nonmarine deposits

Predominantly a well-cemented, heterogeneous mixture of volcanic gravel, sand, silt, and clay. Contains some till and in western Washington is commonly deeply weathered.
State Washington
Name Quaternary nonmarine deposits
Geologic age Pleistocene
Lithologic constituents
Unconsolidated > Fine-detrital (Alluvial, Glacial-outwash)clay and silt
Unconsolidated > Coarse-detrital (Alluvial, Glacial-till, Glacial-outwash)volcanic gravel and sand
Comments Loess is of Palouse Formation (see also WAQce). Unit is fluvial to glaciofluvial in origin (Roberts, 1958). Primarily located near Chehalis and Yakima. Large deposit near Chehalis is primarily gravel and sand outwash with minor silt and clay (Logan Hill Formation); deposit near Yakima may include some of the Thorp Gravel (see WAMPLc) (Walsh and others, 1987).
Stratigraphic units Logan Hill Formation; Cowiche gravel; Palouse 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.

Walsh, T.J., Korosec, M.A., Phillips, W.M., Logan, R.T., Schasse, H.W., 1987, Geologic Map of Washington-Southwest Quadrant: Washington Division of Geology and Earth Resources, Geologic Map GM-34, scale 1:250,000.

Roberts, A.E., 1958, Geology and Coal Resources of the Toledo-Castle Rock District, Cowlitz and Lewis Counties, Washington: U. S. Geological Survey Bulletin 1062, 71 p, 6 pls.

Easterbrook, D.J., 1986, Stratigraphy and chronology of Quaternary deposits of the Puget Lowland and Olympic Mountains of Washington and the Cascade Mountains of Washington and Oregon: Quaternary Science Reviews, v. 5, p. 145-159.

Jones, M.A., 1999, Geologic Framework for the Puget Sound Aquifer System, Washington and British Columbia: U. S. Geological Survey Professional Paper 1424-C, 31 p., 18 pls.

NGMDB product
Counties Cowlitz - Lewis - Lincoln - Thurston - Yakima