The Pleistocene Gastropoda of J. J. Rivers
Jack D. Mount
Department of Earth Sciences, University of
California, Riverside 92502
In volumes 3 (no. 5, p. 69-72; no. 6, unnumbered plate) and 12 (no. 2, p. 29 and unnumbered plate) of the Bulletin of the Southern California Academy of Sciences, J. J. Rivers described five new species of Gastropoda from the Lower and Upper Pleistocene of western Los Angeles County, California. Since the brief descriptions are marginally adequate, at best, figures generally unpublished, and most of the types missing, these mollusks have not been well known to modern researchers. Rivers' names are listed below followed by the type locality and formation, repository of the types, suggested modern assignment, synonyms and age range.
Hyalaea tricuspida Rivers, 1904: Santa Monica, Palos Verdes Sand; unfigured holotype apparently lost; CAVOLINIA TELEMUS TRICUSPIDA (RIVERS) [syn.: Cavolina occidentalis Dall, 1908]; Late Pleistocene to Recent.
Eulima raymondi Rivers, 1904: Santa Monica, Palos Verdes Sand; 5 figured and 2 unfigured syntypes apparently lost, 4 unfigured syntypes in the Department of Earth Sciences, University of California, Riverside (UCR); EULIMA RAYMONDI RIVERS [syn.: Strombiformis riversi Bartsch, 1917]; Late Pleistocene.
Chrysodomus arnoldi Rivers, 1904: San Pedro, Palos Verdes Sand; unfigured holotype apparently lost; CALICANTHARUS FORTIS, (CARPENTER, 1864); Early Pliocene to Late Pleistocene.
Chrysodomus merriami Rivers, 1904: Santa Monica, Timms Point Silt; unfigured holotype apparently lost; COLUS MERRIAMI (RIVERS) [this may be Tritonofusus riversi Martin, 1914]; Late Pliocene? to Early Pleistocene.
Bathytoma clarkiana Rivers, 1913: San Pedro, Palos Verdes Sand; 2 figured syntypes in the San Diego Natural History Museum, 1 unfigured syntype at UCR; MEGASURCULA CARPENTERIANA (Gabb, 1865); Early Pliocene to Recent.
In addition, a specimen collected by Rivers from the Palos Verdes Sand at Santa Monica, figured in The Nautilus,, vol. 20, 1906, pl. 2, fig. 10, as Pleurotoma (Genota) cooperi Arnold, 1903, is now at UCR; MEGASURCULA CARPENTERIANA COOPERI (ARNOLD); Late Pleistocene.
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