The Permian in Washington, US

Paleontology and geology

Although not identified on this map, Permian marine rocks occur in the North Cascades accreted terrane (east of Puget Sound). They contain abundant fusilinid foraminifera, clams, snails, brachiopods and corals, indicating that they formed in warm, shallow seas far to the south of their present location. Tectonic activities later moved these blocks northward and plastered them to the western edge of North America.