i 9 4 HUTTONIAN THEORY 



the earth's topographical features. Nor is it only 

 from the organisms of former epochs that broad gene- 

 ralisations may be drawn regarding revolutions in 

 geography. The living plants and animals of to-day 

 have been discovered to be eloquent of ancient geo- 

 graphical features that have long since vanished. In 

 their distribution they tell us that climates have 

 changed, that islands have been disjoined from con- 

 tinents, that oceans once united have been divided from 

 each other, or once separate have now been joined ; 

 that some tracts of land have disappeared, while others 

 for prolonged periods of time have remained in isola- 

 tion. The present and the past are thus linked 

 together not merely by dead matter, but by the world 

 of living things, into one vast system of continuous 

 progression. 



In this marvellous increase of knowledge regarding 

 the transformations of the earth's surface, one of the 

 most impressive features, to my mind, is the power 

 now given to us of perceiving the many striking con- 

 trasts between the present and former aspects of topo- 

 graphy and scenery. We seem to be endowed with a 

 new sense. What is seen by the bodily eye — moun- 

 tain, valley, or plain — serves but as a veil, beyond 

 which, as we raise it, visions of long-lost lands and 

 seas rise before us in a far-retreating vista. Pictures 

 of the most diverse and opposite character are beheld, 

 as it were, through each other, their lineaments subtly 

 interwoven and even their most vivid contrasts sub- 

 dued into one blended harmony. Like the poet, * we 

 see, but not by sight alone'; and the 'ray of fancy' 

 which, as a sunbeam, lightened up his landscape, is 



