480 University of California Publications in Geology [Vol. 10 



ranges into the foot-hill region of the Sierra Nevada at the present 

 time. According to Joseph Grinnell 11 this form is found chiefly in 

 the Lower and Upper Sonoran life zones, but may occur locally in the 

 Transition zone. 



MACHAERODONTINAE 

 SMILODON( ?), sp. 



The machaerodont eats are known from Hawver.Cave only by the 

 proximal third of a left fibula, no. 19913 (figs. 3a, 36). It is of course 

 impossible on such incomplete material to determine definitely the 

 genus represented. The specimen is, however, so closely similar to the 

 corresponding portion of the fibula of Smilodon calif amicus, occurring 

 abundantly in the Pleistocene of Rancho La Brea, that there is but 

 little hesitation felt in referring it to that form. The machaerodonts 

 have not been recorded from either Potter Creek Cave or Samwel Cave 

 in California, although known to occur in the Conard fissure of north- 

 ern Arkansas 12 and in the Port Kennedy deposit of Pennsylvania. 13 

 The Hawver Cave fragment is then of particular interest in that it 

 records for the first time the presence of the sabre-tooth tiger in cave 

 faunas of this state. 



In expansion of the head and thickness of the shaft, the cave 

 specimen (figs. 3a, 3b) corresponds closely to fibulae of Smilodon 

 calif ornicus from Rancho La Brea and differs in these characters from 

 the true cats. It exceeds, however, the average fibula of Smilodon 

 from the asphalt beds in fore and aft diameter of head. 



The forward extension of the head beyond the tibial facet is not 

 so great as in the Recent California puma, Felis oregonensis oregon- 

 cnsis, but is greater than in the large Rancho La Brea lion, Felis 

 atrox. The shafl of the fibula in Smilodon widens more rapidly to 

 the proximal end to form the head than it does in the Rancho La Brea 

 lion. The machaerodont fibula differs also from that of the lion in 

 being not so greatly depressed on the medial side below the head, and 

 in having a larger, grooved surface on the lateral side for insertion 

 of the posterior portion of the tibio-fibular ligament. In the sabre- 

 tooth tiger the insertion of the external lateral ligament probably 

 did not extend distally as far along the autero-lateral margin of the 



11 Grinnell, J., A distributional list of the mammals of California, Proe. Calif. 

 Acad. Sci., ser. 4, vol. 3, pp. 265-390, pis. 15, 16, 1913. 



12 Brow n, B., The Conard fissure, a Pleistocene bone deposit in northern Arkan- 

 sas : with descriptions of two new genera and twenty new species of mammals, 

 Mem. Amer. Mus. Nat. Hist., vol. 9, pt. 4, 1908. 



is Cope, E. D., Vertebrate remains from Port Kennedy bone deposit, Jour. 

 Acad. Nat. Sci. Phila., ser. 2, vol. 11, 1899. 



