162 University of California Publications in Geology [Vol.11 



The most important differences between P. cf. estrellana and P. 

 generosa appear to be that the former is somewhat longer in propor- 

 tion to the height and has less conspicuous beaks. The posterior dorsal 

 edge on P. cf. estrellana is straight, while on P. generosa it is usually 

 concave; on P. cf. estrellana there is a wide, shallow sinus, which 

 extends from the beaks to the lower side of the truncate posterior end ; 

 this is usually absent on P. generosa, though appearing on some speci- 

 mens. 



The writer exposed an imperfect hinge of the right valve of a 

 specimen of P. cf . estrellana from the Agasoma gravidum beds, appar- 

 ently enough to show that there are specific differences between it 

 and P. generosa. It is very possible that when this form from the 

 Oligoeene and Lower Miocene is compared with the type it will be 

 found to be a new species. 



Family Pholadidae 



Genus PHOLADIDEA Goodall 



PHOLADIDEA aff. PENITA Conrad 

 Poorly preserved specimens of Pholadidca were found at locality 

 1131 extending from basal Oligoeene beds into beds that are presum- 

 ably Tejon, though no Tejon fossils were found at this locality. The 

 species is close to Pholaclidea penita Conrad 135 from which it appears 

 to differ somewhat in outline; the sculpturing is very close. It does 

 not seem best, on account of the poorness of the preservation of the 

 specimens at hand, to describe this form as a new species; the writer 

 feels, however, that with better material it may be found to be new. 



Family Teredinidae 

 Genus TEREDO Linnaeus 



TEREDO sp. indt. 



Fossil wood was found at University of California locality 2753, 

 full of Teredo borings. 



135 For original description of Pholadidea penita, see Jour. Phila. Acad. Nat. 

 Sci., vol. 7, p. 237, pi. 18, fig. 7, 1837 ; also for good description see Arnold, Mem. 

 Calif. Acad. Sci., vol. 3, pp. 184-185, 1903. 



