Washington rocks!: a guide to geologic sites in the Evergreen State

Brief history of Washington's geology

Okanogan Highlands : ancient rock of Northeastern Washington

Columbia Plateau : massive basalt flows ravaged by catastrophic Ice Age floods

Cascade Range: Washington's volcanic backbone

Puget Sound: Glacial ice in a tectonic trough

San Juan Islands: stacked thrust sheets scraped by ice

Olympic Mountains: a youthful coast range

Willapa Hills: sands of the Southwestern Coast.