PEOCEEDINGS 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. From the 

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



Corhula luteola. 

 Tellina modesta. 

 Lucina Nuttallii. 

 Pecten vaucicostatus. 

 Nucula exigua. 

 Hhectaxis punctoccelata. 

 Tornatina ccrealift. 

 Tornatina eximia. 

 Volvula cylindrica. 

 Melampus olivaceus. 

 Dentalium liexagonum. 

 Vitrinella sp. 

 Crucihulum spinosum. 

 Crepidula adunca. 

 SerpuIorMs squamigerus. 

 Litorina scutulata. 

 Lacuna solidula. 

 Rissoina Woodicardi ? 

 Myurella simplex. 



Drillia Hemphillii. 



Mangilia angulata. 



Odostomia gravida. 



Turhonilla chocolata. 



Turhonilla vlrgo. 



Turhonilla torquata. 



Eulima micans. 



Scalar ia indianorum. 



Ceritkiopsis assimillata. 



Olivella Mplicata. 



Olivella hoetica. 



Nassa 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. 



3Iacoma nasuta. 

 Mactra californica. 



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

 Dosinia ponderosa, and Anomia Umatiila, 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^) 

 four or five 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- 



