Miocene marine rocks (WAMI;0)

State	Washington
Name	Miocene marine rocks
Geologic age	Miocene
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Includes wacke and arenite sandstone and tuffaceous sandstone, relative proportions of each unknown. Sedimentary > Clastic > Siltstone (Bed, Carbonaceous, Tuffaceous)Includes carbonaceous, micaceous, and tuffaceous siltstone, relative proportions of each unknown. Incidental Sedimentary > Clastic > Mudstone > Shale (Bed) Sedimentary > Clastic > Conglomerate (Bed)
Comments	Montesano Formation overlies Astoria Formation and not always differentiated from it in the literature. Most of the Montesano Formation, however, maps within the WAMPL unit, and most of the Astoria in this unit (based primarily on Walsh and others, 1987).
Stratigraphic units	Astoria Formation; Clallum Formation (Olympic Peninsula); Montesano Formation (in part); Lincoln Creek Formation (in small part)
References	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. Babcock, R.S., Suczek, C.A., Engebretson, D.C., 1994, The Cresent "Terrane", Olympic Peninsula and Southern Vancouver Island, in Lasmanis, R. and Cheney, E. S., convenors, Regional Geology of Washington State: Washington Division of Geology and Earth Resources Bulletin 80, p. 141-157. Wells, R.E., 1989, Geologic Map of the Cape Disappointment-Naselle River Area, Pacific and Wahkiakum Counties, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1832, scale 1:62,500. Snavely, P.D.,Jr., Brown, R.D., Roberts, A.E., Rau, W.W., 1958, Geology and Coal Resources of the Centralia-Chelalis District, Washington: U. S. Geological Survey Bulletin 1053, 149 p. Walsh, T.J., 1987, Geologic Map of the Astoria and Ilwaco Quadrangles, Washington and Oregon: Washington Division of Geology and Earth Resources Open File Report 87-2, scale 1:100,000.
NGMDB product	NGMDB product page for 30777
Counties	Clallam - Grays Harbor - Jefferson - Lewis - Pacific - Thurston - Wahkiakum

State

Name

Miocene marine rocks

Geologic age

Miocene

Lithologic constituents

Major

Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Includes wacke and arenite sandstone and tuffaceous sandstone, relative proportions of each unknown.

Sedimentary > Clastic > Siltstone (Bed, Carbonaceous, Tuffaceous)Includes carbonaceous, micaceous, and tuffaceous siltstone, relative proportions of each unknown.

Incidental

Sedimentary > Clastic > Mudstone > Shale (Bed)

Sedimentary > Clastic > Conglomerate (Bed)

Comments

Montesano Formation overlies Astoria Formation and not always differentiated from it in the literature. Most of the Montesano Formation, however, maps within the WAMPL unit, and most of the Astoria in this unit (based primarily on Walsh and others, 1987).

Stratigraphic units

Astoria Formation; Clallum Formation (Olympic Peninsula); Montesano Formation (in part); Lincoln Creek Formation (in small part)

References

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.

Babcock, R.S., Suczek, C.A., Engebretson, D.C., 1994, The Cresent "Terrane", Olympic Peninsula and Southern Vancouver Island, in Lasmanis, R. and Cheney, E. S., convenors, Regional Geology of Washington State: Washington Division of Geology and Earth Resources Bulletin 80, p. 141-157.

Wells, R.E., 1989, Geologic Map of the Cape Disappointment-Naselle River Area, Pacific and Wahkiakum Counties, Washington: U. S. Geological Survey Miscellaneous Investigations Series Map I-1832, scale 1:62,500.

Snavely, P.D.,Jr., Brown, R.D., Roberts, A.E., Rau, W.W., 1958, Geology and Coal Resources of the Centralia-Chelalis District, Washington: U. S. Geological Survey Bulletin 1053, 149 p.

Walsh, T.J., 1987, Geologic Map of the Astoria and Ilwaco Quadrangles, Washington and Oregon: Washington Division of Geology and Earth Resources Open File Report 87-2, scale 1:100,000.

NGMDB product

NGMDB product page for 30777

Counties

Clallam - Grays Harbor - Jefferson - Lewis - Pacific - Thurston - Wahkiakum