Middle and lower Eocene volcanic rocks (WAEOv2;0)

State	Washington
Name	Middle and lower Eocene volcanic rocks
Geologic age	Eocene
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff) Incidental Sedimentary > Clastic > Siltstone (Bed, Tuffaceous)Possibly includes some tuffaceous siltstone. Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Possibly includes some tuffaceous sandstone.
Comments	Cresent Formation equivilent to Metchosin (American term versus Canadian term) (Babcock and others, 1994), and almost exclusively referred to as Cresent Formation within Washington (two known exceptions: Henriksen, 1956 ,who maps it as Metchosin in southwestern Washington and Snavely and others, 1958, who maps it, in the Centralia-Chehalis district, as a volcanic sequence of basalt lava flows and breccia of the McIntosh formation). Cresent Formation is at least 5000 ft thick (in Pacific County, Wagner, 1967a, b). Snavely and others, 1958, maps a small chunk of this unit in the Centralia-Chehalis district as a volcanic sequence of basalt lava flows and breccia in the McIntosh formation; I think this outcrop is actually Cresent formation.
Stratigraphic units	Cresent Formation; Metchosin (Vancouver Island)
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. Snavely, P.D. and Wells, R.E., 1984, Tertiary Volcanic and Intrusive Rocks on the Oregon and Washington Continental Shelf: U. S. Geological Survey Open-File Report 84-282, 17 p. Luedke, Robert G., 1998, Maps showing distribution, composition, and age of Early and Middle Cenozoic volcanic centers in Oregon and Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-2291-D, scale 1:1,000,000. https://pubs.er.usgs.gov/publication/i2291D 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. Wagner, H.C., 1967a, Preliminary geologic map of the South Bend quadrangle, Pacific County, Washington: U. S. Geological Survey Open File Reports 67-266, scale 1:62,500. Wagner, H.C., 1967b, Preliminary geologic map of the Haymond quadrangle, Pacific County, Washington, U. S. Geological Survey Open File Reports 67-265, scale 1:62,500. Henriksen, D.A., 1956, Eocene Stratigraphy of the Lower Cowlitz River-Eastern Willapa Hills Area, Southwestern Washington: Washington Division of Mines and Geology Bulletin No. 43, 122 p, 1 pls. 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.
NGMDB product	NGMDB product page for 30777
Counties	Clallam - Cowlitz - Grays Harbor - Jefferson - Kitsap - Lewis - Mason - Pacific - Thurston - Wahkiakum

State

Washington

Name

Middle and lower Eocene volcanic rocks

Geologic age

Eocene

Lithologic constituents

Major

Igneous > Volcanic > Mafic-volcanic > Basalt (Flow, Volcaniclastic-volcanic breccia, Pyroclastic-tuff)

Incidental

Sedimentary > Clastic > Siltstone (Bed, Tuffaceous)Possibly includes some tuffaceous siltstone.

Sedimentary > Clastic > Sandstone (Bed, Tuffaceous)Possibly includes some tuffaceous sandstone.

Comments

Cresent Formation equivilent to Metchosin (American term versus Canadian term) (Babcock and others, 1994), and almost exclusively referred to as Cresent Formation within Washington (two known exceptions: Henriksen, 1956 ,who maps it as Metchosin in southwestern Washington and Snavely and others, 1958, who maps it, in the Centralia-Chehalis district, as a volcanic sequence of basalt lava flows and breccia of the McIntosh formation). Cresent Formation is at least 5000 ft thick (in Pacific County, Wagner, 1967a, b). Snavely and others, 1958, maps a small chunk of this unit in the Centralia-Chehalis district as a volcanic sequence of basalt lava flows and breccia in the McIntosh formation; I think this outcrop is actually Cresent formation.

Stratigraphic units

Cresent Formation; Metchosin (Vancouver Island)

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.

Snavely, P.D. and Wells, R.E., 1984, Tertiary Volcanic and Intrusive Rocks on the Oregon and Washington Continental Shelf: U. S. Geological Survey Open-File Report 84-282, 17 p.

Luedke, Robert G., 1998, Maps showing distribution, composition, and age of Early and Middle Cenozoic volcanic centers in Oregon and Washington: U.S. Geological Survey Miscellaneous Investigations Series Map I-2291-D, scale 1:1,000,000.

https://pubs.er.usgs.gov/publication/i2291D

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.

Wagner, H.C., 1967a, Preliminary geologic map of the South Bend quadrangle, Pacific County, Washington: U. S. Geological Survey Open File Reports 67-266, scale 1:62,500.

Wagner, H.C., 1967b, Preliminary geologic map of the Haymond quadrangle, Pacific County, Washington, U. S. Geological Survey Open File Reports 67-265, scale 1:62,500.

Henriksen, D.A., 1956, Eocene Stratigraphy of the Lower Cowlitz River-Eastern Willapa Hills Area, Southwestern Washington: Washington Division of Mines and Geology Bulletin No. 43, 122 p, 1 pls.

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.

NGMDB product

NGMDB product page for 30777

Counties

Clallam - Cowlitz - Grays Harbor - Jefferson - Kitsap - Lewis - Mason - Pacific - Thurston - Wahkiakum