Oregon-Olympic sedimentary forearc basin 

(Eocene to Miocene) 

(U.S.A. Pacific Northwest, and offshore of Vancouver Island, Canadian Cordillera, unit Czs)

Consists chiefly of three lithofacies: (1) lithic sandstone, shale, and conglomerate of marine fan origin; (2) 
arkosic sandstone, shale, and conglomerate of fluvial and deltaic origin; and (3) volcanic sandstone and 
shale (Heller and others, 1987). The lithic sandstone is present in the Aldwell, Lyre, Hoko, and Makaw 
Formations on the northern Olympic Peninsula (Rau, 1963; Snavely and others, 1980, 1993) and in 
southern Oregon as the Roseburg, Lookingglass and Flournoy Formations (Ryberg, 1984; Molenaar, 
1985). The arkosic facies is present in the Chuckanut and Swauk Formations (Tabor and others, 1984; 
Johnson, 1984; Taylor and others, 1988), and the Tyee and Yamhill Formations in Oregon (Snavely and 
others 1964; Heller and others 1985). The volcanic petrofacies is present in the Blakely and Lincoln Creek 
Formations (Rau, 1967) and the Nestacca and Coaledo in Oregon (Snavely and others, 1969; Baldwin 
1974). REFERENCES: Rau, 1963, 1967; Snavely and others, 1964; 1969; 1980, 1993; Baldwin 1974; 
Johnson, 1984; Ryberg, 1984; Tabor and others, 1984; Heller and others, 1985; 1987; Taylor and others, 
1988; Molenaar, 1985.