!9 18 ] Stock : The Pleistocene Fauna of Haivver Cave 471 



haps the distinctions noted between the faunas of Hawver Cave and 

 those of the Shasta eaves may be attributed in part to a difference 

 in age and in part to the geographic separation of these deposits. 

 It would appear that the latter factor was less potent in causing 

 the differences between the faunas from Potter Creek Cave and 

 Samwel Cave. 



It has already been remarked that, judging from the relative 

 number of extinct species in each of the three cave faunas, Hawver 

 Cave would certainly appear to contain the oldest assemblage. On 

 the basis of number of extinct genera present, however, the Hawver 

 Cave fauna must be considered as somewhat older than the Samwel 

 Cave fauna and slightly, if at all, younger than the Potter Creek Cave 

 fauna. In addition to the larger percentage of extinct forms from 

 Hawver Cave, an age difference between the fauna from this locality 

 and the fauna from Samwel Cave is suggested by the presence in the 

 former of Smilodon(f) , Mylodon and a species of wolf near Canis 

 dims, and by the absence of Preptoceras. It is certain that the dis- 

 similarity in faunas between Hawver Cave and Samwel Cave is nearly, 

 if not fully, as great as between the faunas of Potter Creek Cave and 

 Samwel Cave. 



When contrast is made between Hawver Cave and Potter Creek 

 Cave, we note that faunas from both localities are characterized by a 

 greater number of extinct species than occur at Samwel Cave. In 

 addition to Euceratherium, Megalonyx and Nothrotherivm, which may 

 be considered as typifying deposits of the Sierran foot-hill region, 

 forms occurring in both these deposits and absent from Samwel Cave 

 include Mammut and Bison. A canid species from Hawver Cave is 

 apparently related to Canis dims, a form found at Potter Creek Cave 

 but absent from Samwel Cave. We note also the absence of Prepto- 

 ceras from both deposits. The ground-sloth Mylodon and a sabre- 

 tooth tiger are present at Hawver Cave but absent from Potter Creek 

 Cave, while in the latter deposit are found Arct other ium, Platy- 

 gonus( ?), and a camelid which does not occur at the former cave. The 

 absence of the latter types would appear indicative of a difference in 

 age between Hawver Cave and Potter Creek Cave. It suggests that 

 Hawver Cave contains a slightly later fauna. On the other hand, 

 the possibility remains that these faunas merely supplement each 

 other and that approximately the same stage of the Pleistocene is 

 represented. The ground-sloth Nothrotherium from Hawver Cave is 

 believed to differ subspecifically from the Potter Creek Cave type. 



