Trace fossils with a burrow morphology characteristic of Ophiomorpha nodosa Lundgren occur in upper bathyal subsea fan deposits of the Eocene in northwestern Washington.

The burrows average 2 cm in diameter and branch profusely. Swollen turnabout chambers occur at branching points. Horizontal burrows are most common at the base of sandstone beds. Burrows walls exhibit surface ornamentation including scratch marks and pellet lining, although most burrows are mud-lined and smooth surfaced. These morphologic features conform to those characteristic of Ophiomorpha nodosa Lundgren.

Abundant Ophiomorpha burrows occur in the sandstones and associated siltstones of the lower Eocene "Sandstones of Scow Bay" and upper Eocene Quimper Sandstone and Marrowstone Shale, Marrowstone and Indian Islands, northeast Olympic Peninsula.

The burrows occur in a sandstone-shale sequence with sedimentary features characteristic of subsea fan deposition. Lithofacies are classified using Mutti and Ricci Lucchi's 1972 turbidite facies criteria. Ophiomorpha occurrences are: 14 in Facies B--lenticular channel sandstones; 68 in Facies C--tabular sandstones with shale interbeds ("classical turbidites"); 17 in Facies D--shales with numerous sandstone interbeds; and 4 in Facies E--shales with few sandstone interbeds. Ophiomorpha is most abundant in facies associations consisting of positive megasequences (thinning upward-fining upward) characteristic of channel filling in middle fanlobe environments.

Paleoecology of foraminiferal assemblages from interbedded shales suggests upper bathyal (200 to 1,200 m) water depths. The in-situ fauna consists of abundant specimens of bathyal hyaline foraminiferal superfamilies (Buliminacea, Cassidulinacea, and Discorbacea), keeled and compressed cassidulinids, numerous species of Gyroidina, and bathyal species of Cibicides. Forms

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characteristic of shallower environments represent a displaced fauna.

Recognition of the Eocene Ophiomorpha nodosa Lundgren in the subsea fan deposits of the northeastern Olympic Peninsula documents an upper bathyal occurrence for this trace fossil.

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