238 THE GLACIAL OR ICE EPOCH. 



shrinking and gradually lessening glaciers. Even these, 

 too, vanish in the long-run, and the present order of things, 

 the ordainings of the current epoch, are established. This 

 gradual elevation of the land constitutes the third and last 

 stage of the glacial epoch, the proofs of which are to be 

 found in the moraines, lateral and terminal, that still linger 

 in every glen and corrie of our island, in the re-assorted 

 clays and boulders of the two former stages, in the numerous 

 terraces which mark the successive steps of the land's up- 

 rise, and in the fine silty clays (the " brick-clays " of some 

 geologists), with boreal shells, star-fishes, bones of seals 

 and whales, which fringe our bays and estuaries at various 

 altitudes above the present sea-level. Compared with the 

 earlier stages of the ice-epoch, the traces of this latter stage 

 are still fresh and recent. The mounds of sand and gravel 

 so frequent at the mouths of all. our glens and upland 

 valleys, are but the terminal moraines of the ancient gla- 

 ciers ; the gravelly terraces (in some instances with shells) 

 that fringe so many of our hill-sides, are but the ancient 

 beaches of the gradually uprising land ; the great blocks and 

 boulders so abundantly strewn over our heathy uplands, 

 are but the denuded ice-borne blocks of the two former 

 stages ; and the fine silty " brick-clays " are but the up- 

 raised muds of the deeper sea-bed. Since then, frost, rain, 

 and rivers have done their work on the land's surface, and 

 obliterated many of the ice-traces, yet enough still remains 

 to convince the unbiassed inquirer of its long reign over 

 these northern latitudes during the three successive stages 

 we have here endeavoured to describe. 



The accumulations described in the preceding paragraphs 

 are usually distinguished by such names as " northern 

 drift," " glacial drift," " erratic blocks," and " boulder- 

 clay," all conveying the idea that they have not been de- 



