1919] Merriam: Tertiary Mammalian Faunas of Mohave Desert 525 



This specimen may conceivably be a representative of the Bromo- 

 meryx group with relatively high crown and reduced palaeomeryx 

 fold. Matthew and Cook 30 describe a somewhat similar form from 

 the Snake Creek beds of Nebraska. 



Measurements of no. 21218 



Dm,, anteroposterior diameter along middle of crown 14.6 mm. 



Dm,, transverse diameter across hypoconid 1 2 



Mi, anteroposterior diameter along middle of crown 18 



M,, transverse diameter across hypoconid 14.1 



Mi, height of crown on slightly worn protoconid pillar 1 9 



RICARDO FAUNA 



Eeptilia 



Testudinate remains 

 Carnivora 



Canid, small, near Canis? vafer 

 Leidy 



Aelurodon? aphobus, n. sp. 

 Aelurodon?, possibly aphobus, 



n. sp. 

 Aelurodon?, n. sp. a 

 Aelurodon ?, n. sp. b 

 Aelurodon or Tephrocyon, sp. c 

 Aleurodon or Tephrocyon, sp. d 

 Mustela? buwaldi, n. sp. 

 Ischyrosmilus osborni, n. gen. 



and sp. 

 Felid, large 



Felid, small, not Ischyrosmilus 

 Rodentia 



Lepus?, sp. 

 Proboscidea 



Tetrabelodon?, sp. 



Equidae 



Hipparion mohavense Merriam 



Hipparion mohavense callodonte 

 Merriam 



Hipparion, sp. a 



Hipparion, sp. b 



Pliohippus tantalus Merriam 



Pliohippus fairbanksi Merriam 



Pliohippus, sp. near mirabilis 

 (Leidy) 

 Oreodontidae 



Merycochoerus ? ( Pronomother- 

 ium?) calif ornieus, n. sp. 

 Camelidae 



Procamelus, sp. a 



Procamelus, sp. b. 



Pliauchenia, sp. 



Altieamelus?, sp. 

 Bovidae 



Merycodus, near necatus Leidy 



Relation of the Ricardo Fauna to its Environment 



The beds in which the Ricardo fauna occurs were evidently 

 deposited on plains lying at the eastern base of a late Tertiary Sierra 

 Range rising to a height of several thousand feet above the level of 

 the Mohave area. The elevation of the region as a whole was probably 

 not greater than at present and may have been somewhat less. The 

 Ricardo deposits are probably in part land-laid, and in part water- 



38 Matthew, W. D., and Cook, H. J., Bull. Am. Mus. Nat, Hist., vol. 26, p. 409, 

 1909. 



