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University of California Publications in Geology [ VoL - 10 



Fernando. However, the recent work of English 19 shows that the 

 lower Fernando represents a horizon well down in the Pliocene; the 

 Los Angeles fauna is therefore probably to be regarded as the time- 

 equivalent of only the later phases of the middle Fernando. 



The fauna of the San Diego formation, which has been so thor- 

 oughly studied by Dall 20 at the type locality, and by Arnold 21 at 

 San Pedro, is in many respects more like that from Los Angeles than 

 any of those previously mentioned. Reference has already been made 

 to the boreal character of the two faunas. The San Diego formation 

 at San Pedro has yielded Arnold eighty- four molluscan species, eighty- 

 three of which are determined specifically. Through a typographical 

 error Fusinus (Fusus) barbarensis and Mangilia (Clatlmrella) con- 

 radiana are listed in his report" as extinct ; with this correction 

 (which is made in the faunal list in Professional Paper No. 47, of 

 the U. S. Geological Survey) twelve species ( 14.-4 per cent) are extinct. 

 Thracia trapezoides is the only one of the three restricted Pliocene 

 forms of this locality which occurs in the Los Angeles fauna ; at 

 San Diego Pecten opuntia and P. healeyi occur in addition to 

 this species. The San Diego formation at the type locality is believed 

 by Arnold to include the San Pedro horizon but to extend somewhat 

 lower in the Pliocene. 23 The pectens seem to indicate that the Los 

 Angeles fauna, while probably the correlative of the lower San Diego, 

 is somewhat older than the San Pedro Pliocene. The slightly greater 

 percentage of extinct species and the occurrence of Natica orbicularis 

 and Turris mercedensis in the former may indicate that the Los 

 Angeles horizon belongs even somewhat below the typical San Diego. 



It is the belief of the writer that the fauna obtained from the Los 

 Angeles clays represents the later phases of the middle Fernando. It 

 is probably somewhat older than the San Pedro deposit, but is the 

 equivalent in time of the lower horizons of the San Diego formation. 



is English, W. A., Univ. Calif. Publ., Bull. Dept. Qeol., vol. 8, no. 8, 1914. 



20 Dall, W. H., Proc U. S. Nat. Mus., vol. I, 1878, pp. 10-16, pp. 26-30; 

 Proc. Calif. Acad. Sci., vol. 5, 1873, pp. 296-299. 



21 Arnold, B,, Mem. Calif. Acad. Sci., vol. 3, 1903; IT. S. Geol. Surv. Prof. 

 Paper, no. 47, 1907. 



22 Arnold, K,, Mem. Cal. Acad. Sci., vol. 3, p. 15, 1903. 



23 Arnold, E., Mem. Cal. Acad. Sci., vol. 3, p. 13, 1903 (correlation table); 

 IT. S. Geol. Surv. Prof. Paper, no. 47, 1907. 



