THE FOSSILS OF THE LOWER SAN PEDRO FAUNA OF 

 THE NOB HILL CUT, SAN PEDRO, CALIFORNIA 



By T. S. Oldroyd, 

 Of Stanford University, California 



INTRODUCTION 



The cut through Nob Hill at San Pedro exposed a large deposit of 

 the Lower San Pedro series of the Pleistocene. In July, 1918, the 

 steam shovel had worked its way down to the bed, uncovering no 

 shells of the upper series in the cut, except a few at the south end. 

 This was especially good, as heretofore in most places where the 

 lower series was exposed, the upper series had cropped out above it; 

 as at Deadman's Island. This made collecting in the latter place 

 from the lower series rather uncertain, as the upper would cave down 

 in quantities from the action of the wind and rain, settle on the edge 

 of the lower, and on becoming packed, looked as if it belonged there. 

 This immense deposit, extending the whole length and breadth of 

 the cut and an unknown distance further, was nearly 6 feet thick, and 

 in the center of the cut, where it had not been graded down, was 20 

 feet below the surface and dipped to the northeast. The first layer 

 commencing at the bottom was about 15 inches thick and sparsely filled 

 with shells, mostly bivalves. Next above there was a bed of bivalves 

 about 4 inches thick, composed mostly of Macoma nasuta Conrad, and 

 Macoma secta Conrad; these were very plentiful and in a natural 

 condition as they had lived, and had not been disturbed, but were 

 covered up by about 17 inches of sand in which there were no shells. 

 The next layer was about 4 inches thick, composed of Ostrea luinda 

 Carpenter, and Aletes squamigerus Carpenter. Wliile the life of the 

 bed of Macoma was a short one, as none of them had reached a 

 maximum growth, the bed of oysters had apparently lasted for a 

 much longer period of time. This bed, like that of the Macomas^ 

 was not disturbed but covered up in a natural position. The next 

 layer is a conglomerate mass two feet thick, very compact but not 

 hardened; washed up by some storm, it' contains a great many species 

 from deep Avater, The next and last layer was about 17 inches thick. 



No. 2535. — Proceedings U. S. National Museum, Vol. 65. Art. 22. 



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