Geological Survey Professional Paper 374—G Foraminifera from the Northern Olympic Peninsula, Washington

This report deals with the stratigraphic and ecologic significance of Foraminifera contained in a Tertiary sequence that crops out in the northern part of the Olympic Peninsula, Wash. (pl. 1). The work was done as a part of a program of geologic investigations for oil and gas possibilities conducted by the U.S. Geological Survey. The geology of four 15-minute quadrangles, the Pysht, Lake Crescent, Joyce, and Port Angeles, was mapped and the results published as two separate reports (Gower, 1960; Brown and others, 1960). Samples for foraminiferal study were collected during the course of the geologic fieldwork in the summer months from 1952 to 1956. Stratigraphic sections were measured by plane table and telescopic alidade.

Foraminifera indicative of Eocene, Oligocene, and Miocene age were recognized in the northern Olympic Peninsula. Assemblages compare with previously known faunas from other parts of the west coast and are referred to the Penutian, Ulatisan and marizian stages of Mallory (1959), the Refugian stage of Schenck and Kleinpell (1936), and the Zemorrian and Saucesian stages of Kleinpell (1938).

Detailed studies of the Foraminifera are hampered by their scarcity and poor preservation. Foraminifera are particularly rare in the older part of the sequence but they generally become more plentiful and are better preserved in the younger strata. Many hundreds of samples were taken, but assemblages that are significant of age and environment were obtained from 183 localities.

Several methods of disaggregating the samples were tried, but the kerosene-water method was the most successful. When possible, approximately 150 grams of each sample was washed and all residue that was retained on a 150-mesh screen was examined.

Many members of the U.S. Geological Survey gave assistance on the report. R. D. Brown, Jr., H. D. Gower, and P. D. Snavely, Jr., collected many of the samples, measured some of the sections, and supplied the geologic data upon which parts of this report are based. All photographs of Foraminifera accompanying the report were retouched by Mrs. Mary Wagner.