- Usage in publication:
-
- Duwamish formation
- Modifications:
-
- Named
- Dominant lithology:
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- Clay
- Silt
- AAPG geologic province:
-
- Puget Sound province
Summary:
Well exposed on both sides of Duwamish Valley from north end of Beacon Hill to south city limits of Seattle. Consists of clay and silt with minor peat beds. Massive clay phase well exposed in workings of Klinker Sand and Gravel Co., above West Marginal Way, where it is at least 200 ft thick. Varved clay phase exposed in landslide scars on west side of Beacon Hill west of Marine Hospital and in adjoining low hills just north of Dearborn Street. Both phases of formation overlain by clayey silt and sand with interlayered peat. Overlies Beacon till (new) without evidence of time break. Klinker till (new) overlies different members of formation. Is Pleistocene age.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).