Preliminary Report on the Geology of Southern Snohomish County (PDF)

description

This report from 1973 describes the geology of southern Snohomish County.

excerpt

The map area includes eighty-five square miles in South Snohomish County southeast of Everett, bounded on the west by Interstate 5, on the south by Highway 405 and the Snohomish-King County boundary, on the east and north by the Snohomish River floodplain.

geology of

pdf

https://www.dnr.wa.gov/Publications/ger_ofr73-1_geology_south_snohomish_co_pt1.pdf

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Kabbalah

snippets

The area consists primarily of Tertiary sedimentary and volcanic rocks and Pleistocene glacial and interglacial unconsolidated sediments.
The Whidbey Formation is characteristically compact, bedded, bluish to gray-brown silt and clay. Thin sand layers are present in places, but silt and clay dominate.
Bald Hill, northwest of Monroe, consists primarily of andesite flows. These blue-green porphyritic rocks weather quite readily to a light grey material with a reddish hue which can easily be disintegrated by hand. At several localities on Bald Hill vertical dikes are exposed which contain andesite xenoliths in a fine grained matrix.

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when

1973-11-05