THE ICE AGE 



a great deal about it that seems likely to remain un- 

 explained. 



The bones that were found are not buried in lime or 

 any preserving stone ; but lie in sand where one would 

 expect them to have perished long ago if they had 

 been of any great age. Yet side by side with them 

 are the bones of a long-extinct horse ; and there is 

 no tradition among the Indians to-day of any huge 

 beast corresponding to the Mylodon. Sir E. Ray Lan- 

 kester has pointed out that the whole of South America 

 has been submerged and has risen (and is rising still) 

 for many centuries. Possibly the rocks and high lands 

 where the Mylodon cavern occurs formed an island during 

 the submergence, where a number of early animals took 

 refuge and survived until the re-elevation of the land 

 and so lived on in the present condition of the land sur- 

 face until fifty or a hundred years ago. The great land 

 tortoises (like the Galapagan* tortoise) have similarly 

 survived on a few equatorial islands. Possibly, though 

 it does not seem very likely, the Mylodon is still living 

 in similar caverns in this region, as yet unvisited by 

 man. 



In Australia, the land of the marsupials or mammals 

 with pouches, the bones of many gigantic creatures be- 

 longing to that tribe of animal have been found. Giant 

 kangaroos, twice as tall as the biggest living kangaroo, 

 wombats and voles as big as a rhinoceros, have been 

 discovered. One of these is the Diprotodon, which Sir 



* Of the Galapagos Islands .- 

 278 



