354 Neogene Paleontology in the Northern Dominican Republic 18

This study concerns a group of taxa formerly included in the Superfamily Volutacea, most characterized by the presence of columellar plications. In all there are 19 species, divided among eight genus-group taxa. Numerically, the largest genera are Vasum, with six species, and Turbinella, with four species. The other groups include only a few species each: Scaphella s.s.- 1; Lyria s.s. – 3; Lyria (Enaeta) -1; Harpa-1; Morum s.s. -1; and Morum (Oniscidia)-2. Only one species, Scaphella (Scaphella) striata (Gabb), occurs in beds of the Gurabo Formation that represent deep-water deposition. All other occur in shallow-water beds, often in association with coralline facies. The shallow-water portion of the Gurabo Formation contains the largest number of species, 11 in all; however, only two are confined to these beds, the other also in the other shallow-water formations as well. The stratigraphically older Baitoa Formation conations seven species, of which five are endemic (three certain and two presumed to be form the same unit). Although the Mao Formation is generally representative of extremely deep-water deposition, five species occur in gravity-flow deposits of shallow material into the deeper debs. Fourteen of the species were described from the Dominican Republic by Sowerby, Gabb, and others; two are new to the fauna (one known previously only from the Chipola Formation, and one known previously only from the Recent of the Caribbean); and three are new species: Lyria gabbi, from the Baitoa Formation; Turbinella pilsbryi, from unnamed beds of Cercado age; and T. praetextilis, from the shallow-water Gurabo Formation.