Vol. XI] BERRY— FOSSIL CHITONS 4QJ 



species, and am therefore uncertain to which formation the 

 horizon belongs. The small Mopalia, a single valve of which 

 is the only chiton discovered, seems, however, to be inseparable 

 specifically from those occurring so commonly in the Pleisto- 

 cene of the same vicinity. 



6. Excavation on Fourth Street, between Hill Street and 

 Broadway, Los Angeles, California (Moody). 



Moody ( :16, p. 42) has recorded an undetermined chiton 

 from this exposure. In the same paper he described the as- 

 sociated fauna and its relationships in some detail/ 



Santa Barbara Formation: 



7. Deadman Island, San Pedro, California (Chace). 

 This deposit has been described very fully by Arnold ( :03, 



p. 14-17). He records one chiton: 



Cryptochiton stelleri (MiddendorfT) 

 To this is here added : 



Katharina tnnicata (Wood) 



PLEISTOCENE 



The chiton fauna of the Pleistocene deposits studied, again 

 all southern Californian, shows near relation to the living fauna 

 not only by essential identity of species, but by the compara- 

 tively great development of this portion of the fauna when con- 

 sidered with relation to the weak position it occupies in the 

 Pliocene. In the San Pedro Formation, which is the only one 

 from which we have any chitons, they divide as readily as the 

 remaining molluscan fauna into the two primary series estab- 

 lished by Arnold. 



Lower San Pedro Series: 



8. Deadman Island, San Pedro, California (Arnold). 



2 Since this paper was written, the recovery of two of Moody's specimens enables 

 them to be recorded as follows: 



1. Callistochiton crassicostatus Pilsbry. The single specimen seen is a well pre- 

 served head valve of somewhat peculiar aspect, and it is possible that this determination 

 will have to be revised later on. 



2. Callistochiton palmulatus Carpenter. The single specimen is a well preserved tail 

 valve measuring, long. 4.3, diam. 5.2, alt. 4.8 mm. It seems much nearer typical 

 palmulatus than most of the other fossil specimens seen, although a few of those from 

 Long Wharf Canyon, Santa Monica, are somewhat similar. 



