104 THE AGE OF MAMMALS 



geological age in the Rocky Mountains; it may as well be an insectivore. 

 The comparison of the primitive carnivores or Creodonta in the two 

 countries is closer, namely, of the Thanetian species of Arctocyon, with its 

 omnivorous, bear- or raccoon-like teeth, with those of Clcenodofi of northern 

 New Mexico. Similarly the Thanetian Procynictis parallels Chriacu.s of 

 the American family Oxyclgenidae, and Hycenodictis is similar to the 

 American Dissacus of the Mesonychidie. Contrary to the recent opinion 

 of Deperet, it does not appear probable that the presence is demonstrated 

 of any of the modernized animals, e.g. artiodactyl or perissodactyl un- 

 gulates, in this imperfectly known fauna. Similarly we note the absence 

 of, or have thus far failed to discover in this fauna any relatives of the 

 Edentata (Taeniodonta) or Amblypoda,^ both characteristic of the Torrejon. 

 Of course the Cernaysian river deposit presents a very incomplete picture 

 of the mammalian life of France during this period, for as observed by 

 Lemoine and Deperet these mammal remains were only those which were 

 washed into streams and carried to the sea near by. 



The associated freshwater fishes of northern France and Belgium are 

 related to the garpikes (Lepidosteus) and bow-fins (Amia), now met with 

 only in the great rivers of North America. There are many turtles, all 

 marsh and river varieties, Crocodilia, both of the crocodile, or Nile type, 

 and the long-snouted, gavial type, of the Ganges. Extremely adapted to 

 aquatic life is the rhynchocephalian lizard Simcedosaurus, related to the 

 Champsosaurus of the Basal Eocene of North America. The flightless 

 bird Gastornis, belonging to the order of Chenomorphae, according to von 

 Zittel,^ is remarkable for its huge proportions and its powerful legs in con- 

 trast with its feeble wings. 



The flora of this Basal Eocene period indicates a moderately warm and 

 temperate climate free from great extremes, including palms {Flabellaria) , 

 laurels (Laurus), cinnamons (Cinnamomum) , and a doubtfully referred 

 grass (Poacites).^ In the extreme north the Basal Eocene flora^ of 

 Greenland, Iceland, and Spitzbergen included lindens, alders, magnolias, 

 poplars, and birches, indicating a temperature similar to that of south 

 temperate France or California at the present time. 



Basal Eocene of North America 



Puerco and Torrejon Formations. — In northwestern New Mexico, at 

 the head of the Puerco River on the divide between the Rio Grande and 

 San Juan rivers, are the Basal Eocene, post-Cretaceous beds which Pro- 



' As above noted (p. 100), the inclusion in this stage of mammals found in the tapper 

 Landenian of Orsmael and Erquelinnes, namely, Amblypoda (Coryphodon) and Perisso- 

 daetyla (primitive Equidae) is extremely doubtful. 



- Von Zittel, Text-Book of Palaeontology, transl. by Eastman, Vol. II, 1902. 



^ De Lapparent, Traite de Geologie, 1906, p. 1492. 



* Ibid., p. 1504, citation from Heer's Flora fossilis arctica. 



