CHAPTER XII 



LIFE OF THE TERTIARY PERIOD 



Directly we pass from the Cretaceous into the lowest of the 

 Tertiary deposits — the Eocene — we seem to be in a new 

 world of life. Xot only have the whole of the gigantic Dino- 

 saurs and the accompanying swimming and flying reptiles 

 totally disappeared, but they are replaced in every part (tf the 

 world by Mammalia, which already exhibit indications of being 

 the ancestors of hoofed animals, of Carnivora, and of Quadru- 

 mana. 



Order — Ungulata 



In the Lower Eocene strata of ISTorth America and Europe, 

 the sub-order Condylarthra is well represented. These were 

 primitive, five-toed, hoofed animals which, Dr. A. Smith Wood- 

 ward tells us, '" might serve well for the ancestors of all later 

 Uiigulata." One of these, Phenacodus primcevus, was found 

 in the Lower Eocene of Wyoming, U.S.A., and was about 4 

 feet long exclusive of the tail (see Eig. 72). Considering that 

 this is one of the very earliest Tertiary mammals yet discov- 

 ered, it is interesting to note its comparatively large size, its 

 graceful form, its almost full series of teeth, and its large five- 

 toed feet; affording the starting-point for diverging modifica- 

 tion into several of the chief types of the higher mammalia. 

 So perfectly organised an animal could only have been one of 

 a lono^ series of forms brido:inc: over the 2:reat c'ulf between 

 it and the small rat-like mammals of the ^lesozoic period. 



Another sub-order is the Amblypoda, of which the Corypho- 

 don of Europe and Xorth Americn is one of the best known. 

 This was about 6 feet long, and was first obtained from our 



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