PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES FOURTH SERIES Vol. XXXI, No. 13, pp. 341-347 May 20, 1963 INTERPRETATION OF THE INVERTEBRATE FAUNA FROM THE UPPER PLEISTOCENE BATTERY FORMATION NEAR CRESCENT CITY, CALIFORNIA By Warren O. Addicott 345 Middlefield Road, Menlo Park, California This paper documents an assemblage of late Pleistocene invertebrates occurring as a basal fossiliferous lens on the Crescent City platform, an emergent wave-cut terrace on the northern California coast near the Oregon border. This is the only recorded late Pleistocene invertebrate fauna in northern California north of the San Francisco Bay district, although ex-tensive areas of similar and probably contemporaneous wave-cut terraces occur along the coast between Crescent City and San Francisco. Fossils were collected from a sea cliff exposure west of Crescent City which is located near the southern edge of a broad marine terrace extending nearly thirty-five miles along the coast from the mouth of Smith River to a point south of Crescent City. The Crescent City fauna lived in a moderately shallow-water, nearshore-shelf environment of both rocky and sand-covered bottom. Sub-sequent redistribution and mixing by current or wave action brought to-gether an assemblage of diverse ecological types. Composition of the as-semblage, principally mollusks, indicates marine water temperatures not apprecialjly different from conditions offshore from Crescent City today. Study of topographic maps and the sailing chart of the area suggests that the fauna lived on or adjacent to a prominent northwesterly trending off-shore reef which extended some seven or eight miles in a northwesterly direction from the late Pleistocene coastline.  Marine Biological Laboratoryj MAY 2 D 1953 WOODS HOLE, MASS.