Vol. XI] BERRY— FOSSIL CHITONS 



Material Examined : 



439 



Remarks: The sculpture of L. dentiens is extremely similar 

 to that of Cyanoplax raymondi (Pilsbry), but the short, 

 wide valves, delicate structure of the shell, and short 

 sutural laminae lead me to refer the fossil specimens to 

 the former species. Mr. and Mrs. Oldroyd obtained it so 

 abundantly in the Nob Hill Cut that it seems strange that, 

 except for one perhaps questionable specimen from Deadman 

 Island, it has not been detected in any of the other horizons. 

 The specimens are so fragile that none were obtained in an 

 altogether perfect condition, but in spite of this and the lack 

 of any terminal valves in the series, the identification seems 

 reasonably certain. 



Genus Nuttallina Carpenter, 1879 



7. Nuttallina calif ornica (Nuttall, 1847) 



(Plate III, figs. 1-12.) 



1847. Chiton calif ornicus Nuttall in Reeve, Conch. Icon., v. 4, 



Chiton, sp. 90, pi. 16, f. 90; detail pi., f. 89. 

 1864. Acanthoplcura scabra Carpenter, Rep. Brit. Assoc. Adv. 



Sci., 1863, p. 527, 603, 649. 

 1893. Nuttallina calif ornica Pilsbry, Man. Conch., (1), v. 14, 



p. 279, pi. 54, f. 23-24; pi. 56, f. 12-18. 

 1919. Nuttallina cf. fluxa Chace and Chace, Lorquinia, v. 2, p. 



42 [2] (recorded from Pleistocene of Pt. Fermin, 



Cal.). 



Diagnosis: Valves heavy, low, more or less triangular, 

 median ones strongly beaked, though beaks and entire posterior 

 portion often lost by erosion; sculpture comprising a narrow 

 sulcus bounding the jugal tract on each side, an oblique ridge 

 dividing the lateral and pleural areas, and a coarse, rather zig- 



