28 



One group of the Eocene marsh-dwelling hoofed animals which 

 did not advance much in brain-power though growing rapidly in 

 bulk of body as it passed to the grassy plains, has also survived, but 

 only by a curious accident. This is the order of elephants, in which 

 during successive geological periods after the Eocene, the legs grew 

 continually longer while the neck remained comparatively short^ and 

 ability to feed on the ground could only be maintained by the 

 lengthening of the face and lower jaw. When this strange makeshift 

 had reached its extreme mechanical inefficiency (at the end of the 

 Miocene period), the chin suddenly shortened in the animals that 

 survived, while the long soft face thus left without support eventually 

 developed into the proboscis which is so characteristic a feature of 

 the existing elephants. 



All the other Eocene and Oligocene mammals, however, which 

 increased in bodily bulk without at the same time advancing in 

 brain-power, soon became extinct. They were, so to speak, pre- 

 cocious sports. Several of them, such as the Dinoceras and 

 Titanotherium ol North America and the Avsinoithevium of Egypt,, 

 were provided with formidable horns. 



Some of the earliest mammals of the Eocene period migrated 

 from the land into the sea, and eventually became completely 

 adapted for an aquatic life in the form of whales and porpoises. 

 These pioneers of sea-mammals have not yet been discovered ; but 

 the Zeuglodonts, of which a skull and other remains have been 

 found in the Barton Clay, afford some clue to the nature of their 

 land-ancestry : Specimens from the Eocene of Egypt suggest that 

 this ancestry is to be found among the flesh-eating Creodonta. 



Our knowledge of all these phenomena in the history of 

 mammalian life still depends on very fragmentary material from 

 many localities. In western Europe at least it is increased mainly 

 by accidental discoveries made by those who actually reside on the 

 Lower Tertiary formations and keep a watchful eye on all excava- 

 tions and natural exposures. There is much need for this watchful- 

 ness along the Hampshire coast, where every well-preserved fossil 

 bone or tooth is likely to prove of scientific value. 



