USGS Visual Identifier
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Geologic Unit: Cowlitz

Cowlitz Formation (OR*,WA*)

Eocene, middle*
Eocene, late*
Geologic Province:
Oregon-Washington Coast Ranges province*

Areal Extent:

Type Locality:
Type section: canyon of Olequa Creek between towns of Winlock and Olequa, in southwestern Lewis Co., and northwestern Cowlitz Co., WA (Weaver, 1937).

(alphabetical) [not adopted by USGS]: Goble Member (WA) or Goble Volcanics Member (OR,WA), Olequa Creek Member (WA), Pe Ell Volcanics Member (WA), Stillwater Creek Member (WA).

Unit Name History:
Named (Weaver, 1912).
Overview; Areal limits (Weaver, 1937).
Areal limits (Warren and others, 1946).
Revised in lower Cowlitz River-eastern Willapa area to include Stillwater Creek, Olequa Creek, Goble, and Pe Ell members [not adopted by USGS] (Hendriksen, 1956).
Age modified (Walker and McLeod, 1992).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses ().

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013