AN EARLY OLIGOCENE CHEMOSYNTHETIC COMMUNITY FROM THE MAKAH FORMATION,NORTHWESTERN OLYMPIC PENINSULA, WASHINGTON

A small, allochthonous, localized mass of limestone is present within deep-water strata of the early Oligocene part of the Makah Formation e xposed at Shipwreck Point on the Olympic Peninsula, Washington State. This limestone is a methane-derived authigenic carbonate, as evidenced by faunal-sedimentologic associations and stable isotopes; it is encl osed in siltstone that is nearly barren of mega-fossils. Fossils from the limestone represent a diverse chemosynthetic community that includ es more than 20 species. The fauna consists of eight bivalve genera (i ncluding Calyptogena and Modiolus), 13 gastropods (including Provanna) , one scaphopod, one chiton, and vestimentiferan? worm tubes. We repor t the first fossil record for the genus Provanna and the first record for chitons at ancient cold-methane seeps.