Mackintosh — The Sea v. Rain and Frost. 67 



Not one out of a hundred of these blocks could have fallen into the 

 places they now occupy, and they must therefore have been carried 

 by a strong current of water, unless it can be shown that they were 

 dispersed by glacial action. In the south and south-east of England 

 the newer sandstones would appear to be able to resist atmospheric 

 denudation, as may be inferred from the present form of the stones 

 composing so-called Druidical Circles or temples, such as Stonehenge.^ 



Limited Atmospheric Denudation proved by Glacial marMnys. — It is 

 admitted by all geologists that ice-marks on rocks, and moraines in 

 valleys, have resisted atmospheric denudation to such an extent 

 that many parts of Wales and Cumberland retain the same general 

 features which they presented at the close of the Glacial-period. It 

 is not necessary to show that very delic.ate scratches have been 

 preserved in exposed situations. The mere fact that the smoothed 

 and rounded surfaces of rocks, many of them of considerable extent, 

 have been peipetuated, is a clear proof that they have not been 

 subjected to any process worthy of the name of weathering. But if 

 these rocky areas have retained their ice- worn shape, have we not 

 reason to believe that neighbouring areas, and indeed all areas 

 equally unsusceptible to atmospheric action, have likewise retained 

 their ancient surface-configuration ? The same consideration applies 

 to moraines, which in most valleys have only been visibly interfered 

 with, and that to very limited extent, by the action of streams. The 

 subaerialist's answer to all this will probably be in the sublime 

 language of Play fair : " It aifords no presumption against the reality 

 of the progress of decay that, in respect of man, it is too slow to be 

 immediately perceived. The utmost portion of it to which our 

 experience can extend is evanescent in comparison with the whole." 

 But the Post-glacial period is so very much longer than the period 

 of human experience, that the subaerial geologists may be fairly 

 called upon to establish a good claim in favour of rain and frost 

 during that period before proceeding to speculate on what may 

 previously have occurred. The last few thousand years furnish 

 sufficient exemplifications of the denuding power of the sea, and of 

 its capacity to produce inequalities which are fac-similes of those 

 found in inland districts. 



Denuding Power of the Sea. — It would be difficult to exaggerate 

 the battering, disentangling, undermining, excavating, upthrowing, 

 and transj)orting power of the sea ; and it is worthy of remark that 

 while it is mainly a laterally-operating and undermining agent, the 

 atmosphere is mainly a vertically-operating and degrading agent. 

 The sea, therefore, has the first claim to be considered the ca,use of 

 all phenomena which on any considerable scale show traces of 

 having been produced by undermining. The subaerialists ought to 

 assign a reason whj they make a distinction between a cliff now 

 washed by the waves and a precisely similar clifi" a few miles 

 inland, or a fac-simile of both at a greater distance from the sea. 



^ Though I have not lately had an opportunity of visiting the spot, I have no 

 doubt that the rocky projections (including the Toadstone) and cliffs, near Tunbridge 

 "Wells, could be shown to be the work of the sea. 



