16 (JALIFOKNIA ACADEMY OF SCIENCES. 



The fauna of the San Pedro Pliocene is a decidedly northern or boreal one 

 in the sense that many of the species found in the San Pedro Pliocene are living now 

 only in the colder waters far to the north of San Pedro. The large percentage of the 

 living species found now living only north of San Pedro shows this; and in addition, 

 the species in this fauna still living at San Pedro are neai'ly all of a northern 

 or boreal type. No characteristic southern species are found in this fauna. 



The evidence shows that the climate in the vicinity of San Pedro during that 

 part of the Pliocene epoch in which these beds were deposited was probably 

 different from the present one. A boreal fauna deposited in comparatively shallow 

 water near the shore implies a boreal climate, at least in proximity to the coast; 

 the fauna contains so many shallow water species, and the lithologic evidence showing 

 that the deposits containing the fauna were laid down near the shore is so strong, that 

 it cannot be regarded as a deep-water temperate fauna. The evidence, then, shows 

 that during upper Pliocene times the climate of this part of Southern California was 

 colder than at present; and if this was true of southern California, it seems reasonable 

 to infer that the colder climate affected the whole coast from San Pedro northward. 



There are several reasons for calling the lower sandstone strata of Deadman 

 Island Pliocene. In the first place, 17.3 per cent, of the fauna of these strata are 

 extinct at the present time. This is conclusive evidence that the beds are not 

 Pleistocene, but are of an earlier epoch. They are overlain unconforraably by 

 strata of Pleistocene age, which implies that there was a period of denudation 

 between the epoch of the deposition of the lower beds and the Pleistocene. Besides, 

 these strata rest unconformably upon the Miocene shales. That the Deadman Island 

 Pliocene beds are of upper Pliocene origin is shown by the fact that their fauna 

 gradually grades into the living fauna of San Pedro through that of the overlying 

 Pleistocene beds. The gap between the faunas of the Deadman Island Pliocene and 

 the overlying Pleistocene beds, though distinct, is not wide. 



In his correlation paper on the Neocene, Dr. Dall says:' "It appears that on 

 Deadman Island near Point Fermin at least three distinguishable strata appear, the 

 uppermost of which is certainly Pleistocene, while the others are Neocene and the 

 middle layer probably Pliocene." The middle layer referred to is the brown sand- 

 stone which rests on the Miocene shales. 



The Deadman Island Pliocene beds are lithologically and faunally similar to 

 the Pliocene beds at San Diego, and have been correlated with them by Dr. Dall.^ 

 In the same table he places the San Diego beds below the Merced series. This does 

 not accord with the evidence offered by the San Pedro Pliocene strata. The San 

 Pedro beds are very near the top of the Pliocene, and have a northern fauna; the 

 relative position of the Merced series is uncertain, and it has a fauna containing such 

 southern forms as Area and Dosinia, with an echinoderm, Scntella interlineata, which 

 has never been found in either the San Diego or San Pedro formations, or in any 

 formation overlying the Merced series. The Merced series has been subject to 



> Correlation Papers, Neocene. By W. H. Dall and G. D. HarriB. Bull. U. 8. Geol. Sur., No. 81, 1892, p. 216. 

 -' North Aujerican Tertiary Horizons. By W. H. Dall. 18tb Ann. Eep. U. 8. Geol. Sur., Part II, 1898, p. 336. 



