PROLEGOMENA 45 



cestors which, in the climate of the glacial epoch, prob- 

 ably flourished better than they do now. Compared 

 with the long past of this humble plant, all the history 

 of civilized men is but an episode. 



Yet nothing is more certain than that, measured by 

 the liberal scale of time-keeping of the universe, this 

 present state of nature, however it may seem to have 

 gone and to go on for ever, is but a fleeting phase of her 

 infinite variety; merely the last of the series of changes 

 which the earth's surface has undergone in the course 

 of the millions of years of its existence. Turn back a 

 square foot of the thin turf, and the solid foundation of 

 the land, exposed in cliffs of chalk five hundred feet 

 high on the adjacent shore, yields full assurance of a 

 time when the sea covered the site of the "everlasting 

 hills"; and when the vegetation of what land lay nearest, 

 was as different from the present Flora of the Sussex 

 downs, as that of Central Africa now is. 2 No less 

 certain is it that, between the time during which the 

 chalk was formed and that at which the original turf 

 came into existence, thousands of centuries elapsed, in 

 the course of which, the state of nature of the ages 

 during which the chalk was deposited, passed into that 

 which now is, by changes so slow that, in the coming 

 and going of the generations of men, had such witnessed 

 them, the contemporary conditions would have seemed 

 to be unchanging and unchangeable. 



But it is also certain that, before the deposition of 

 the chalk, a vastly longer period had elapsed, through- 

 out which it is easy to follow the traces of the same 

 process of ceaseless modification and of the internecine 

 struggle for existence of living things; and that even 

 when we can get no further back, it is not because there 

 is any reason to think we have reached the beginning, 



2 See "On a Piece of Chalk," Essays, viiiri. [T. H. H.] 



