1916] Moody: Fauna of the Fernando of Los Angeles 



4!) 



Seven-Mile Beach is now generally conceded to belong to the Pleisto- 

 cene ; Martin 17 lists twenty-three species from this horizon, all of which 

 are living. From the lower Merced 106 species have been obtained, of 

 which fifty-seven, or 53.7 per cent, are extinct. The restricted Pliocene 

 forms common to the two faunas are T arris mercedensis, Thracia 

 trapezoides, and Pecten healeyi, which has so far been reported only 

 from the Purisima. It thus appears that the main body of the Merced 

 antedates the Los Angeles deposit, and that the latter formation is 

 the time equivalent of only the later horizons of the central California 

 Pliocene. 



The Fernando formation, which includes most of the marine Plio- 

 cene deposits of southern California, is, in the Santa Clara Valley, 

 divided by Eldridge and Arnold 18 into three faunal horizons. The 

 lowest horizon is considered as approximately equivalent to the 

 Etchegoin, the middle is probably the correlative of the Purisima and 

 the lower part of the San Diego formation, while the upper is well 

 within the Pleistocene, the higher horizons being correlated with the 

 upper San Pedro. The fauna of the lower Fernando, as listed by 

 Arnold, contains twenty-nine determined species, of which 55 per 

 cent are extinct ; thirty-one species are reported from the middle 

 division, with 45 per cent extinct ; from the upper division fifty-one 

 species are named, only 12 per cent of which are extinct. From a 

 consideration of percentages alone the Los Angeles fauna would 

 unhesitatingly be placed near the fauna of the upper Fernando; but, 

 as the Los Angeles fauna is nearly three times the size of the latter, 

 perhaps a more significant feature is the number of restricted Pliocene 

 species which appear from the two formations. In the lower Fernando 

 thirteen restricted species are reported, none of wdiieh are found in 

 the Los Angeles material. The middle Fernando contains twelve Plio- 

 cene forms, with Pecten healeyi alone common to two faunas. No 

 characteristic Pliocene forms occur in the upper division. The major- 

 ity of the species here classed as "restricted" in the middle and lower 

 Fernando are new ; the only Pliocene form that enjoys even a moderate 

 geographic range is the above-mentioned pecten. On this basis, includ- 

 ing the Astrangia described by Nomland and the ten species described 

 in this paper, seventeen restricted Pliocene forms occur in the new 

 fauna ; its affinities are thus with the middle and lower divisions of the 



i- Martin, B., Univ. Calif. Publ., Bull. Dept. Geol., vol. 9, no. 15, 191(3. 



is Eldridge, G. H., and Arnold, B., U. S. Geol. Surv. Bull. no. 309, pp. 23-28, 

 1907. 



