THE EOCENE PERIOD. 297 



west of England, there occur fossil remains of all the three 

 living types of Crocodilians namely, the Gavials, the true 

 Crocodiles, and the Alligators (fig. 226) though at the 



Fig. 226. Upper jaw of Alligator. Eocene Tertiary, Isle of Wight. 



present day these forms are all geographically restricted in 

 their range, and are never associated together. 



Almost all the existing orders of Birds, if not all, are 

 represented in the Eocene deposits by remains often very 

 closely allied to existing types. Thus, amongst the Swimming 

 Birds {Natatores) we find examples of forms allied to the 

 living Pelicans and Mergansers; amongst the Waders (Gral- 

 latores] we have birds resembling the Ibis (the Numenius 

 gypsorum of the Paris basin) ; amongst the Running Birds 

 (Cursores) we meet with the great Gastornis Parisiensis, which 

 equalled the African Ostrich in height, and the still more 

 gigantic Dasornis Londinensis ; remains of a Partridge rep- 

 resent the Scratching Birds (Rasores] the American Eocene 

 has yielded the bones of one of the Climbing Birds (Scan- 

 sores), apparently referable to the Woodpeckers ; the Protornis 

 Glarisiensis of the Eocene Schists of Claris is the oldest 

 known example of the Perching Birds (Insessores} ; and the 

 Birds of Prey (Raptores} are represented by Vultures, Owls, 

 and Hawks. The toothed Birds of the Upper Cretaceous 

 are no longer known to exist ; but Professor Owen has 

 recently described from the London Clay the skull of a very 

 remarkable Bird, in which there is, at any rate, an approxi- 

 mation to the structure of Ichthyornis and Hespcrornis. The 

 bird in question has been named the Odontopteryx toliapicus, 

 its generic title being derived from the very remarkable char- 

 acters of its jaws. In this singular form (fig. 227) the margins 



