Found on wet woody creekside debris. Very small, only a few mm.
Turkey-Tail (Trametes versicolor) Typically grows in rows or overlapping shelves on stumps and logs of hardwoods.
https://www.mykoweb.com/CAF/species/Trametes_versicolor.html
Fungi of California: Home page https://www.mykoweb.com/index.html and https://www.mykoweb.com/CAF/ and https://mykoweb.com/CAF/skey.html and https://www.mykoweb.com/CAF/keys/index.html
California Mushrooms: The Comprehensive Identification Guide, D. Desjardin, M. Wood, and F. Stevens, 2nd printing 2019
Mushrooms of the Redwood Coast: A Comprehensive Guide to the Fungi of Coastal Northern California, N. Siegel and C. Schwarz, 2016