Fig. 2QA. View of Dove Dale, Derbyshire. Showing undercutting m limestone rock at a, C, and m, by alma 

 spheric action, and at e, by indirect action of water. The undercutting shows in hard rock the varying stability o 

 the limestone, or the action of springs at those points. The same form or profile of alternating vertical wall and slop< 

 at a lower angle is well marked in Fig. 29A. This is the same profile as a Gothic buttress, which is a shape wel 

 adapted for stability under atmospheric influences, 



