PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 27 



STRATA OF THE SAN DIEGO PENINSULA. 



The long, low, narrow strip of land lying between San Diego Bay and 

 the ocean is locally known as the Peninsula. It appears to have been 

 pierced formerly by narrow channels or outlets by which the waters of 

 the bay communicated with the sea, and even now, in heavy storms, 

 the surf breaks over the barrier. At high- water mark is a stratum 

 about four feet thick, containing fossils mingled in a confused manner, 

 above which is a bed of fine sand extending to the surface of the pen- 

 insula, and having a total thickness of some twelve feet. Prom the 

 lower bed (A) were obtained the following species: — 



Corbula luteola. 

 Tellina modesta. 

 Lucina Nuttallii. 

 Pecten paucicostatus. 

 Nucula exigua. 

 Ehectaxis punctocozlata. 

 Tornatina cerealis. 

 Tornatina eximia. 

 Yolvula cylindrica. 

 Melampus olivaceus. 

 Dentalium hexagonum. 

 Vitrinella sp. 

 Crucibulum spinosum. 

 Crepidula adunca. 

 Serpulorbis squam igerus. 

 Litorina scutulata. 

 Lacuna solidula. 

 Eissoina Woodicardi ? 

 Jlyurella simplex. 



Drillia HempMllii. 



Mangilia angulata. 



Odostomia gravida. 



Turbonilla chocolata. 



Turbonilla virgo. 



Turbonilla torquata. 



Eulima micans. 



Scalar ia indianorum. 



Ceritli iopsis assimillata. 



Olivella bipUcata. 



OUvella boetica. 



Fassa fossata var. 



Nassa perpinguis. 



Neverita, var. alta. 



Nitidella Gouldii. 



Amphissa versicolor. 



Pteronotus festivus. 



Fish teeth and a sp. of Serpula. 



From the sand bed (B) were obtained, — 



Periploma argentaria. 

 Macoma secta. 

 Macoma indentata. 



Macoma nasuta. 

 2Iactra californica. 



In the lowest part exposed of bed A are found Cardium procerum, 

 Dosinia ponderosa, and Anomia Umatula, but they do not seem to be 

 scattered through the general body of the stratum. 



STRATA OF THE MAINLAND. 



On the mainland near the town of San Diego, the land is rather low, 

 gradually rising inland toward some bluffs. To the eastward of the 

 town, or what is known locally as the ''railroad laud", a stratum (A 2 ) 

 four or live feet thick is exposed at high-water mark, and, like the 

 stratum A of the peninsula, contains a confused aggregation of fossils, 

 at the bottom of which is a layer of the upper valves of Anomia lima- 



