MERRIAM: THE FAUNA OF RANCHO LA BREA. 221 



Figures of a nearly complete skeleton and of a perfect skull of this species 

 were used in illustration of popular articles published by Merriam in 1908 and 

 1909. 14 



The most recent discovery of remains of Canis dirus is that reported by 

 Freudenberg 15 from Tequixquiac, Mexico. At this locality the posterior region 

 of a skull has been found which closely resembles the specimens from Rancho 

 La Brea. 



Geological Occurrence and Geographical Distribution of Canis dirus 



The fairly authenticated occurrences of Canis dirus known to the writer 

 include Leidy 's type specimen from Indiana ; the material from the lead region 

 of the Upper Mississippi described by Allen; a specimen from the Sheridan 

 formation of Kansas, now in the American Museum; Cope's specimen from 

 Texas; the California specimens from Livermore Valley, Tulare County, and 

 Rancho La Brea; and the Mexican specimens described by Freudenberg. All 

 of the material referred to G. dirus has been obtained from deposits held to be 

 of Pleistocene age. There is reason for believing that the horizons at which 

 these specimens have been found at different localities do not differ greatly, but 

 a discussion of the time relation of these occurrences is best considered in a 

 division of this memoir following a discussion of the fauna. 



The collection of remains associated with the type specimen, including, as 

 it does, on the one hand, such extinct forms as Megalonyx jeffersonii, Tapirus 

 hagsii, and Equus americanus, and, on the other hand, the Recent Bison ameri- 

 canus and Gervus virginianus, cannot represent other than Pleistocene time. 



The Texas specimen described by Cope seems to have occurred at the same 

 horizon as Mylodonf sodalis, Elephas primigenius, Equus excelsus, E. semi- 

 plicaius, E. tau, E. major, Holomeniscus sulcatus, and H. macrocephalus. This 

 assemblage including the three genera Equus, Elephas and Holomeniscus must 

 be considered as Pleistocene. 



The lower jaw which Leidy described from Livermore Valley, California, 

 is presumed to have been asociated with a number of remains representing other 

 mammalian forms. This material includes the type specimen of a very large 

 cat, Felis imperialis, a bison referred to Bison latifrons, and a large camel. 

 The presence of Bison latifrons may be considered as evidence of Pleistocene 

 age, though it is uncertain how closely the specimens were associated. 



The fragment of a jaw from Tulare County described by Merriam was asso- 

 ciated with a portion of the skull of an edentate nearly related to Mijlodon, and 

 is presumably Pleistocene. 



The material from Rancho La Brea described in the following paper is 



14 Merriam, J. C, Sunset Magazine, Oct., 1908, p. 172. Also Harper's Weekly, Dec. IS, 1909, p. 11. 

 is Freudenberg, W., Geol. u. Palae. Abh., N.F., Bd. 9, Heft 3, p. 22, 1910. 



