Sept, J. Duane. 2009, The Beachcomber’s Guide of Seashore Life in the Pacific Northwest.
Yates, S. 1998. Marine Wildlife: From Puget Sound Through the Inside Passage.
Harbo, R.M. 1999. Whelks to Whales: Coastal Marine Life of the Pacific Northwest.
Kozloff, E.N. 1973. Seashore Life of Puget Sound and the San Juan Archipelago.
Identifying plants and animals on the beach
http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/index.html (includes some species that may not occur in Puget Sound)
Invasive species in Puget Sound