TERTIARY. 421 



the still more remarkable Dinocerata (Dinoceras, Uintatherium, 

 Tinuceras). The Ohiroptera, or bats, make their first appear- 

 ance. There are as yet no true Carnivora, and Didelphys still 

 survives both in Europe and in North America. Marine snakes 

 (Paheophis), a gavial (Gavialis dixoni), and various chelonians 

 occur in association with fish-remains in the Bracklesham 

 Beds. 



The Upper Eocene fauna occurs in Europe in the marine 

 Barton Clay and the overlying freshwater beds of Hordwell, 

 Hampshire ; in the freshwater limestone of Bembridge, Isle of 

 Wight ; in the gypsum of Montmartre, near Paris ; and in the 

 lignites of D^briige, near Apt, Vaucluse. In North America it 

 characterises the lacustrine Uinta Formation of Colorado and 

 Utah. The Creodonta are now of less importance than before, 

 and true Carnivora are met with for the first time, at least in 

 Europe (Gynodictis). The Condylarthra are few, and the Am- 

 blypoda have completely disappeared in the North American 

 region to which they were restricted. The Perissodactyla are 

 still numerous, and the most important new form is Palceo- 

 therium in Europe ; but the Artiodactyla attain the most 

 remarkable development both in Europe and North America. 

 On the former continent there are the pig-like Cheer opotamus, 

 and the primitive forerunners of the ruminants, Hyopotamus 

 (Ancodus) and Xiphodon ; while a remarkable short-lived 

 family exhibiting three-toed spreading feet, is represented by 

 Anoplotherium and Diplobune. In America there are the 

 Oreodonts (Protoreodon) and primitive camels (Leptotragulus), 

 which must have been still more nearly ruminants. The 

 Rodentia are now very numerous and varied ; on the other 

 hand lemurs appear for the last time on both continents. 

 The opossums (Didelphys) are still abundant. Marine mam- 

 mals occur for the first time, the primitive whale, Zenglodon, 

 being found in Europe, northern Africa, and North America ; 

 while a single Cetacean vertebra of a more modern type has 

 been discovered in the Upper Eocene of Hampshire. Then i> 

 also some fragmentary evidence of Siren ia in northern Italy. 



It must be added that the European Upper Eocene mam- 

 malian fauna is best represented in certain phosphate-bearing 



