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



wegii (not known to occur north of Monterey), Nuttallina 

 californica, Mopalia lignosa (not positively recorded south of 

 San Luis Obispo County). M. acuta (unrecorded north of 

 Monterey), M. ciliata, Placiphorella velata, Cryptochiton stcl- 

 Icri, Chaetopleura gemma, I schno chiton fallax, I. magdaleu ca- 

 sts, I. coo peri, Callistochiton decoratus punctoco status (this 

 one barely recorded from as far north as Monterey), C. palmu- 

 latns mirabilis, — as far as it goes it is like calling the roll on a 

 Pacific Grove beach ! This is again brought out rather better 

 by means of a table. Callistochiton decoratus ferminicus, be- 

 cause unknown in the recent fauna, is left out of account. 



Relations of Lower San Pedro Chiton Fauna with 

 Living Fauna of Monterey Region 



Number of Per cent, 



species of total 

 Common and characteristic at Monterey or not 



known to occur elsewhere 15 83.3 



More common to north or south but recorded 



from Monterey 3 16.7 



Living rarely to north of Monterey region 4 22.2 



Living rarely to south of Monterey region 2 11.1 



Not known to occur north of Monterey region. . . 5 27.8 



Not known to occur south of Monterey region. . . 7 38.9 



Not known to occur in region of Monterey 



Summing up it may be said that the chiton remains offer 

 decided evidence that while the oceanic temperatures of south- 

 ern California were very distinctly cooler during the Lower 

 Pleistocene period than at the present time, the difference was 

 nevertheless very little, if any, greater than that now prevailing 

 between the waters of Monterey and Los Angeles counties, 

 and, if the chitons are a true criterion, was quite probably about 

 the same. 



Upper San Pedro Series: 



The total number of species here listed from the Upper San 

 Pedro is 11. These may be given tabular treatment as follows : 



Relations of Upper San Pedro Chiton Fauna with Living 

 Fauna of Corresponding Latitude 



Number of Per cent, 



species of total 



Extinct or unknown living 2 18.2 



Now living commonly in same region 5 45.5 



Now living in same region but infrequent 2 18.2 



Now living on other parts of coast, but not known 



to occur in same latitude as fossils 2 18.2 



Now living more commonly to north than south. . 2 18.2 



Now living more commonly to south than north. . 2 18.2 



Known to occur only to north 1 9.1 



Known to occur only to south 1 9.1 



