A NEW RECORD OF THE RARE BIVALVE LIMA HAMLINI IN THE PLIOCENE OF LOS ANGELES, CALIFORNIA
by Jack D. Mount¹
Recently the State of California started preparations for widening the San Bernardino Freeway as it passes through the Repetto Hills on the east side of Los Angeles. Last month I visited one of the new road cuts (this habit of checking out new excavations is one of my more active and profitable pastimes) and was rewarded with a number of specimens of the rather rare early Pliocene bivalve Lima hamlini Dall. Since I have long been interested in the geology and paleontology of the Repetto Hills, this find is extra lucky and interesting.
The fossil locality, the largest of the new road cuts, is in the City Terrace area of Los Angeles on the south side of the San Bernardino Freeway immediately opposite of the campus of the California State College, Los Angeles. The road cut extends almost the entire length between Eastern Avenue and the Long Beach Freeway (see my geologic map of the area printed last year in this bulletin (Mount, 1969)). The site is registered in the Department of Geology, California State College, Los Angeles, as CSCLA Locality 792. The locality is in the Fernando Formation very near the base of that unit. The fossils occur in the dark grey siltstone at the base of the road out.
Lima hamlini Dall, 1900, p. 15-16.
Lima (Acesta) hamlini Dall, Woodring, 1938, p. 47-49, plt. 8.
This giant Lima was named and described from specimens collected by Homer Hamlin (a Los Angeles City engineer during the turn of the century) from the Third Street tunnel in downtown Los Angeles.
Fig. 1. Lima hamlini Dall, x1
Dall, W. H., 1900, A new species of Lima: The Nautilus, vol.14, no.2, p.15-16.
Mount. J. D., 1969, Sedimentologic and paleoenvironment study of a portion of the Puente Formation, Los Angeles, California: Bull. So. Calif. Paleo. Soc., vol.1, no.8, p.1-6.
Woodring, W. P., 1938, Lower Pliocene mollusks and echinoids from the Los Angeles basin, California: U.S.G.S. Prof. Paper 190, 67 p.
¹Department of Geology, University of California, Los Angeles 90024.
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