BY HUGH MILLER. 309 



upon the Weald, which contains within a few lines the essential 

 pith and marrow of the argument.^ Messrs. Foster and Topley, 

 in 1866, contributed a comprehensive memoir on the same region 

 to the Geological Society. f The controversy that ensued need 

 not be followed. If it did not establish the atmospheric theory 

 in all cases, or to the satisfaction of all minds, it at least demon- 

 strated atmospheric waste to be equal to its task. Escarpment 

 districts may have been rough hewn by other forces, like the 

 marble that is first blocked into a form directly related to the 

 sculpture ultimately produced; but few now really deny that 

 atmospheric influences have modified the ground to a figure 

 whose lines, at earlier times, lay hid within the solid. The con- 

 troversy perhaps culminated with the production of Mr. "Whita- 

 ker's conclusive paper on the Chalk and Tertiary Escarpments, 

 which presents the arguments in a form wholly unanswerable 

 by advocates of the marine hypothesis. J 



I must not pass to a consideration of the phenomena of the 

 Escarpments I describe without recognising my obligations to 

 the above-named authorities, and others elsewhere referred to, 

 which are so great that references very inadequately represent 

 them. Prof. Eamsay's teachings, especially, I have so long and 

 so completely assimilated that it were scarcely more impossible to 

 distinguish one by one the elements that lay the foundations of 

 a constitution. 



Development of Escarpments. — I have remarked that if a model 

 constructed of sloping layers of wood and clay were exposed to 

 rain, the clay would sink into grooves. But to induce erosion it 

 must be provided that the water be able to run off. In like 

 manner in Nature, the better the provision for free flow the 

 more rapid and powerful the resulting action. 



Suppose the elevated ground between two large rivers to bo 

 represented by the space between the upright lines of the letter 



* Physical Geology and Geography of Great Britain, 2na Edition. 



t Qi\art. Jour. Oeol. Soc, Vol. XXIII. 



t Geol.Mag., Vol. rv.. 18fi7. 



