Miocene-Pliocene marine rocks (WAMIPO;0)

State	Washington
Name	Miocene-Pliocene marine rocks
Geologic age	Miocene-Pliocene
Lithologic constituents	Major Sedimentary > Clastic > Siltstone (Bed) Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Mostly lithofeldspathic and feldspatholithic but locally tuffaceous or feldspathic. Minor Sedimentary > Clastic > Conglomerate (Bed) Incidental Sedimentary > Clastic > Mudstone (Bed)
Comments	Montesano Formation overlies Astoria Formation and not always differentiated from it in the literature. Most of the Montesano Formation, however, maps within this unit, and most of the Astoria in the WAM unit (based primarily on Logan, 1987a,b, and Walsh and others, 1987).
Stratigraphic units	Montesano Formation; Astoria Formation (in 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. Rau, W.W., 1967, Geology of the Wynoochee Valley Quadrangle, Grays Harbor County, Washington: Washington Division of Mines and Geology Bulletin no. 56, 51 p. Logan, R.L., 1987a, Geologic Map of the South Half of the Shelton and South Half of the Copalis Beach Quadrangles, Washington: Washington Division of Geology and Earth Resources Open File Report 87-9, 16 p., 1 pl. Logan, R.L., 1987b, Geologic Map of the Chehalis River and Westport Quadrangles, Washington: Washington Division of Geology and Earth Resources Open File Report 87-8, 18 p., 1 pl.
NGMDB product	NGMDB product page for 30777
Counties	Grays Harbor - Mason

State

Washington

Name

Miocene-Pliocene marine rocks

Geologic age

Miocene-Pliocene

Lithologic constituents

Major

Sedimentary > Clastic > Siltstone (Bed)

Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Mostly lithofeldspathic and feldspatholithic but locally tuffaceous or feldspathic.

Minor

Sedimentary > Clastic > Conglomerate (Bed)

Incidental

Sedimentary > Clastic > Mudstone (Bed)

Comments

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

Stratigraphic units

Montesano Formation; Astoria Formation (in 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.

Rau, W.W., 1967, Geology of the Wynoochee Valley Quadrangle, Grays Harbor County, Washington: Washington Division of Mines and Geology Bulletin no. 56, 51 p.

Logan, R.L., 1987a, Geologic Map of the South Half of the Shelton and South Half of the Copalis Beach Quadrangles, Washington: Washington Division of Geology and Earth Resources Open File Report 87-9, 16 p., 1 pl.

Logan, R.L., 1987b, Geologic Map of the Chehalis River and Westport Quadrangles, Washington: Washington Division of Geology and Earth Resources Open File Report 87-8, 18 p., 1 pl.

NGMDB product

NGMDB product page for 30777

Counties

Grays Harbor - Mason