402 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



In the succeeding- year, Orcutt ('89, p. 71) reports the find- 

 ing- of "Chiton (valves) " from "about two miles south of Ocean 

 Beach [San Diego], near the top of the cliff." 



Ashley ('95, p. 327, 343) records "Cryptochiton c.f. stelleri" 

 from Purissima in San Mateo County, and Ischnochiton 

 regularis from the "Pliocene" (Pleistocene) at San Pedro. 



I find nothing further until the publication of Arnold's great 

 monograph on the Tertiary and Quaternary of the San Pedro 

 region ( :03, p. 15, 19, 28, 40, 42768, 85, 342-343), where the 

 following three fossil species are recognized : 



Ischnochiton regularis (Cpr.) — Pleistocene San Pedro. 

 Cryptochiton stelleri (Midd.) — Pliocene Deadman Island. 



Pleistocene " 

 Mopalia cilia ta (Sby.) [=muscosa of this work] — - 



Pleistocene San Pedro. 



The same three species are also listed by Arnold three years 

 later in his monograph of the Californian Tertiary and Quater- 

 nary Pectens ( :06, p. 31, 35, 36). 



Oldroyd ( :14, p. 81) records Ischnochiton conspicuus Cpr. 

 from the Pleistocene of Signal Hill, Long Beach, California. 



Moody ( :16, p. 42) records an undetermined chiton from the 

 Fernando Formation of the Pliocene at Los Angeles, Cali- 

 fornia. 



Chace ( :16, p. 71-72) lists the following from the Pleisto- 

 cene of Deadman Island, California, thus increasing the number 

 of chiton species up to this time identified as fossils to seven : 



Katherina tunicata "Sby." 

 Ischnochiton conspicuus Carpenter. 

 Mopalia hindsii "(Sby.) Reeve." 



The next year the same writer materially increased the list 

 by reporting the following from the Pleistocene of Santa 

 Monica, California ( :17, p. 30) : 



Ischnochiton acrior Carpenter 



conspicuus Carpenter 



clathratus (Reeve) \=sanctcemonic<z Berry 

 of the present paper] 



