A NEW GENUS OF CRYPTIC LUCINID - BIVALVE FROM EOCENE COLD SEEPS AND TURBIDITE-INFLUENCED MUDSTONE, WESTERN WASHINGTON

Two previously undescribed species of Bivalvia of Eocene age are herei n tentatively considered to belong to the family Lucinidae because of their ligament areas and elongated anterior adductor scars. Both speci es are elongate for a lucinid, have edentulous hinges, striated muscle scars, and are placed in the new genus Cryptolucina. Both are found i n the Humptulips Formation of middle to late Eocene age in western Was hington, and both Cryptolucina megadyseides new species and C. elassod yseides new species are associated with deep-water, cold-seep limeston e. Cryptolucina megadyseides is also associated with turbiditic mudsto ne.