Reviews — Mackintosh's Scenery of England 8f Wales. 467 



through vast regions marked out by even-topped mountains far above 

 the sea, and by plateaux of equal height, now scattered over the field 

 of vision, and disconnected by the loss of intermediate ground, once 

 flat and high, but since furrowed and removed by the slow and 

 unaided action of rain or glaciers. Others would refer the uniformity 

 of the mountain -heights to the general level of the old upraised 

 ocean-floor, and assign to the ready wave-line of the grudging sea 

 the credit of removing the original soft material of the surface, as 

 well as much of the hard rocky matter, along the many lines of 

 shrinkage-crack, of fissures due to contortion, and other dislocations 

 of the upheaved strata, until the sea was left behind ; and then the 

 air, the rain, frost, snow, and glacier were left to do their work in 

 moulding both cliff and incline of the new land into highlands and 

 lowlands, rugged or smooth, steep or sloping, bare or verdant, ac- 

 cording to the nature of rock and climate. 



In former days, many a book was written about the effects of a 

 supposed universal deluge in modifying the contours of any part of 

 the globe ; but though they became waste paper, the idea of oceanic 

 action having wholly caused the outlines of mountain and valley 

 lived on, until the thoughts of such acute observers as Hutton gave 

 life to the modern science of geology, and each of nature's agents — 

 the chemical action of the air, the ripping frost, the grinding 

 glacier, the soaking rain, and the rushing torrent, as well as the 

 pounding waves and shifting tides, had each their claim allowed 

 them. It is, then, to all of these, in their manifold diversity of 

 operation, that the Denudation or stripping bare of the exposed 

 surface of the earth is due ; but to what degree one set or other 

 of the agencies have done their work, in any given region, cannot be 

 determined without a knowledge of its geological history and 

 structure, and without an acquaintance with all the phenomena 

 consequent on the separate or combined action of the said agencies 

 on different rocks under different circumstances. In so wide a 

 field of research, there are many observers, and not a few 

 record their views or the results of their work. Several 

 members of the Geological Survey of Grreat Britain and Ireland, 

 much occupied in field work, have been strongly smitten by the 

 force of rain and moved by the vehemency of ice-action ; and hence 

 bold theories have been advanced and defended by them, wherein 

 the atmospheric powers are so mighty that great Neptune would 

 appear to have been forgotten, were it not that to him has been 

 apportioned the remote and almost inconceivable work of planing 

 down the risen continent, for ^olus, with his wind and rain, to 

 fret into the many-featured lands. A waiting belief, however, that 

 the work of denudation should be more equally divided, seems to 

 have survived among other geologists, who write in the Geological 

 Magazine and communicate with the Geological Society". And 

 indeed, foreign geologists seem still to be actuated by the usual 

 belief that the retreat of the sea originated the main furrows and 

 slopes on the land, and that rivers have long been filling up many 

 of the larger vallej^s, whilst cliffs are being made along the slopes 

 that stay at the wave-line. 



