Numerous specimens of the neritid gastropod Nerita (Bajanerita) n. subgen. californiensis (White, 1885) are present in the Upper Cretaceous Rosario Formation at Punta Banda, Baja California, Mexico (Figure 1). Marincovich (1975) assigned these strata . . .

Two new genera and ten new species of shallow-marine, warm-water gastropods are reported from several Upper Cretaceous formations found between British Columbia and southern California. The buccinid Zaglenum new genus is represented by two new species . . .

The clypeasteroid echinoid Astrodapsis bajasurensis n. sp. is described from upper middle Miocene beds of the Isidro Formation near the mouth of Arroyo Mezquital on the Pacific coast of north-central Baja California Sur, Mexico. The new species is the . . .

The Cretaceous and early Cenozoic species of the shallow-marine, warm-water bivalve Plicatula from California (United States) and Baja California (Mexico) are reviewed, and three new species are named. All of these species are representatives of Plica . . .

The marine bivalve Fimbria susanensis n. sp. is reported from the uppermost Paleocene part of the "Meganos Stage" in the upper Santa Susana Formaton, Simi Hills, southern California. Fimbria pacifica n. sp. is reported from the middle lower Eocene "Ca . . .

Three new species of the shallow-marine, warm-water bivalve Plicatula are reported from the upper Paleocene Santa Susana Formation of southern California. Plicatula simiensis new species is from the middle part of the formation on the south side of Si . . .

Four new molluscan species, a bivalve and three gastropods, are named from shallow-marine, lower Upper Cretaceous (Cenomanian Stage) strata in Oregon. The laternulid bivalve Cercomya ( Cercomya ) hesperia new species is from the Bernard Formation in e . . .

Praehyalocylis cretacea (Blanckenhorn, 1889), a pteropod previously known only from upper Eocene to middle Miocene strata in Europe and Turkey, is reported for the first time in similar age rocks in the northwestern United States. Of the 238 specimens . . .

The trochid archaeogastropod Margarites (Pupillaria) columbiana n. sp., the mytilid bivalve Modiolus (Modiolus) willapaensis n. sp., and the vesicomyid bivalve Calyptogena chinookensis n. sp. are described from the earliest known fossil communities as . . .

Five new mollusks are described from shallow-marine deposits of the lower middle Eocene Llajas Formation, northeastern Simi Valley, southern California. Most of the mollusks are confined to a 1-m-thick bed informally known as the "Stewart bed" and are . . .