CHAPTER II 



THE EOCENE OF EUROPE AND NORTH AMERICA 



The Eocene was originally defined as the dawn of the recent species of 

 marine molluscs. It subsequently came to be regarded also as the dawn of 

 mammalian life. We now realize that it was more truly the sudden expan- 

 sion and evolution of the mammals after what appears to have been a long 



ENGLAND 

 GERMANY 

 SOUTH AFRICA 

 ROCKY MOUNTAINS 

 NORTH CAROLINA 

 PATAGONIA 



Fig. 19. — Chief areas in which mammal deposits of the Age of Reptiles have been dis- 

 covered. 1. North America, Laramie (Cretaceous), Judith River (Cretaceous), Morrison 

 (Jurassic); 2. North Carolina (Upper Triassic) ; 3. Germany (Upper Triassic) ; 4. England, 

 Purbeck (Upper Jurassic), Stonesfield slate (Middle Jurassic) ; 5. South Africa, Stormberg 

 Beds (Upper Triassic) . 6. Patagonia (Age doubtful). 



period of very slow development during the Age of Reptiles. The true dawn 

 of the mammals had occurred some 15,000,000 years earlier, even before the 

 opening of the Age of Reptiles. This is truly a blank historic period, some- 

 what in the sense in which the term is applied to human history, because 

 during the Age of Reptiles our documents are very rare and widely scattered. 

 The few black dots on the accompanying map of the world are placed on all 

 the geographic points on the entire globe where the remains of mammals of 

 the Reptilian Age have thus far been recorded. 



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