SOUTH-WEST IRELAND. 181 



is similar. If the land were to sink below its 

 present level, the sea would gradually enter all 

 the low-seated transverse valleys, as well as the 

 longitudinal valleys, accomplishing at least some 

 denudation as it advanced; but if the land were 

 to rise subsequently, rain and rivers would take 

 possession of exactly the same valleys and ravines, 

 and commence to denude ; therefore it seems to be 

 as much a question of time and opportunity as of 

 efficiency, which has done most of the work ; since 

 whichever held the ground longest ought to have 

 had most effect, other things being equal. Another 

 thing militates against meteoric abrasion, unaided by 

 faults, having cut the transverse valleys ; and that 

 is, that the sides of such valleys are more or less 

 abrupt, whereas this denudant usually tries to form 

 slopes. It must, however, be allowed, as shown pre- 

 viously, that when this force works conjointly with 

 breaks, abrupt steeps may sometimes result. 



It has been shown that the sea is now excavating 

 longitudinal valleys nearly similar to those that now 

 exist in South-west Cork, allowing for subsequent 

 meteoric abrasion and ice action ; also, that it is able to 

 cut transverse valleys, while the positions of all the 

 transverse valleys, and probably all the longitudinal 

 ones, were determined by systems of breaks or faults. 

 Therefore it seems evident that the present valleys 

 are not solely due to rain and rivers, but rather to 



