16 CAI.IFOUNIA ACADKMV (»K SCIKNCI>!. 



The fnmia of tlu' Sun IVdnt I'liocoiie is a dccidodh' nortlicni or l)ori'iil one 

 in tlu' sense thnt iniiiiy of tlie species foninl in llie San IVdro IMiocene are livinj;; now 

 only in the coMer waters far to the north of San IVdro. Tlie hir<;o poroenta<i;e of the 

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

 the species in this fauna still livin.n at San Pedro arc nearly ail of a northern 

 or horeal type. No characteristic southern species are fonnd 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 

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

 water near the shore im|)lies a Imreal climate, at least in proximity to the coast; 

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

 that the depasits 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 Deadraan 

 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 unconformably 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, 

 the.se strata rest unconformal)ly upon the Miocene shales. That the Dcadman 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 

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

 middle layer probably Pliocene." The middle layer referred to is the I)rown 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, Scutella inter lineata, 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 



' OorrcUtton Papen. Neocene. By W. H. Dall and O. D. HanH. Bnll. V. 8. Geol. Siir., No. M, 1892, p. 216. 

 5 Norih Imcrlcui Tertiary Horizons. By W. 11. Dall. 18th Ann. Rep. U. 8. Geol. Sur., Part II, 1898, p. 336. 



