Mattole, or Mattole–Bear River, is an extinctAthabaskan language once spoken by the Mattole and Bear River peoples of northern California. It is one of the four languages belonging to the California Athabaskan cluster of the Pacific Coast Athabaskan languages. It was found in two locations: in the valley of the Mattole River, immediately south of Cape Mendocino on the coast of northwest California, and a distinct dialect on Bear River, about 10 miles to the north.
Goddard, Pliny Earle (1929). "The Bear River Dialect of Athapascan." University of California Publications in American Archaeology and Ethnology 24 (5):291-334, 1929.
Golla, Victor (2011). California Indian Languages. Berkeley: University of California Press. ISBN 978-052-026667-4.
Li, Fang-Kuei (1930). Mattole: an Athabaskan language. Publications in Anthropology, Linguistics Series. Chicago, Ill.: The University of Chicago Press.
Yeadon, David, “California’s North Face”, National Geographic, vol. 184, no. 1, p. 48-79, July 1993.