UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 7, No. 17, pp. 341-358 Issued September 19, 1913 



NOTHROTHERIUM AND MEGALONYX 



PROM THE 



PLEISTOCENE OF SOUTHERN CALIFORNIA 



BY 



CHESTEK STOCK 



CONTENTS 



PAGE 



Introduction 341 



Nothrotherium graciliceps, n. sp 342 



Diagnostic Characters of Species 343 



Skull 343 



Dentition 349 



Eelation to Nothrotherium shastense 350 



Nothrotherium (?), sp 350 



Megalonyx californieus, n. sp 352 



Diagnostic Characters of Species 352 



Anterior Limb 352 



Posterior Limb 355 



INTEODUCTION 



Remains of Nothrotherium and Megalonyx have been recorded 

 from the cave deposits of northern California, but have not been 

 reported from the southern part of the state. In the Pleistocene 

 asphalt deposits of Rancho La Brea numerous remains of gravi- 

 grade edentates include both Nothrotherium and Megalonyx, 

 along with representatives of the Mylodontidae. The genera 

 Nothrotherium and Megalonyx, which are usually thought of as 

 living in a region of more rugged topography than the habitat 

 of Mylodon, are but sparsely represented in this fauna, in con- 

 trast with the abundant remains of the Mylodontidae. In the 



