Outlines of Geology. ^1 



flource of those effects which we have referred to extraordinary 

 and occasionally acting forces ; they have assumed the present 

 rivers as the excavators of their own valleys, and ordinary vol- 

 canic fires as the indurators and elevators of strata from the 

 bosom of the deep ; they think that the washing down of finely- 

 divided matter formed by the action of air and water upon the 

 present surface, and the inroads of the ocean as manifested by the 

 abrupt precipices and shingles of the beach, are sufficient evi- 

 dence of the slow but sure destruction of the present order of 

 things ; but such actions are not only of very circumscribed ex- 

 tent, they are absolutely inefficient ; and even if we draw unli- 

 mitedly upon time^ as the theorists, in opposition to all chrono- 

 logical evidence, have done, their tendency is often the very reverse 

 of that which they would substantiate. The fact is, that the 

 wasting and wearing causes that now exist, are either too trifling 

 to be taken into the account, or are counterbalanced by renova- 

 tions and re-accumulations ; in proof of this the barrows of the 

 aboriginal Britons have been well adduced by Mr. Conybeare *, 

 as retaining the pristine sharpness of their outline, after a lapse 

 of little less, and probably more, than two decades of centuries : 

 even the fosse that surrounds them is not filled up. " Causes, 

 then, which in 2000 years have not, in any perceptible manner, 

 affected these small tumuli, often scattered in very exposed situa- 

 tions upon the crests of our hills, can have exerted no very great 

 influence on the mass of those hills in any assignable portion of 

 time which even the imagination of a theorist can allow itself to 

 conceive ; and where circumstances are favourable to a greater 

 degree of waste, still there is often a tendency to approach a 

 maximum at which further waste will be checked; the abrupt 

 cliff will at last become a gentle slope, and that slope become de- 

 fended by its grassy coat of proof" Even the ocean itself throws 

 up shingle banks and marsh lands, which check its further inroads. 

 So tliat these supposed destructive powers, as they seem to the 

 superficial observer, or to the biassed theorist, are soon found to 

 -I 



• CoDjbeare and Phillip*: Outlines of Geology, page xxxii. 



