270 RECENT FORMATIONS. 



may "be arranged into Pre-human and Human the former 

 containing no traces of man or of his works, the latter being 

 here and there characterised by such remains. And even this 

 Human period may be conveniently subdivided into Pre- 

 historic and Historic the former, like the flint implements, 

 shell-mounds, and cave-dwellings, dating back far beyond 

 the reach of history, the latter coming within periods to 

 which we can assign something like a date in years and 

 centuries. But whatever the arrangement, we clearly per- 

 ceive that some are very ancient so ancient as to merge 

 into the close of the glacial period, and others very recent 

 so recent as to be still in progress of formation. Nor let it 

 be imagined that, because recent, these accumulations are 

 limited and insignificant. All that is necessary to make 

 them rival the older formations in extent and thickness is 

 time, and this is an element as unlimited in the future as 

 it has been prodigal in the past. 



During the deposition of the more ancient, the mam- 

 moth, woolly-haired rhinoceros, hippopotamus, cave-lion, 

 cave-bear, hyaena, and great Irish deer, were inhabitants of 

 Western Europe ; herds of mastodon roamed over the river 

 and lake flats of North America; the plains of South 

 America were densely peopled by the megatherium, megal- 

 onyx, glyptodon, mylodon, and macrauchene ; and Austra- 

 lia, with more gigantic forms of kangaroo and other marsu- 

 pials. At this period we have no traces of man save in 

 Southern and Western Europe * (the only tracts yet suffi- 

 ciently examined) ; and there savage races seem to have lived 

 in caves and wigwams, fashioned stone and flint implements, 



* "We do not lose sight of the fact, that implements fashioned out of the 

 native quartzite of India have been found in the alluvial laterite of Madras 

 and North Arcot, but merely hold it subordinate till the discovery of as- 

 sociated organisms enable geologists to form a more definite idea of the 

 relative antiquity of these lateritic deposits. 



