THE EARTH'S SURFACE SEA ACTION. 43 



one another and the rocks. Consequently it is only in 

 cooses, or such like confined places, they are capable 

 of acting as abraders. 



If the sea be watched during action, its principal 

 work, even in the softest shales, will appear to be 

 due to wedges of either air or water forced into 

 cracks, crevices, and other vacancies, by which rock 

 masses are prized out, and high cliffs are thus 

 undermined and brought down. The sea waves seem 

 never to - work but in conjunction, with meteoric 

 abrasion, which is often more rapid than the marine 

 worker. Consequently many cliffs are not perpen- 

 dicular, meteoric abrasion wearing back the upper- 

 most portion more quickly than the sea can quarry 

 away the base. Under favourable circumstances the 

 sea may form perpendicular cliffs, such as those on the 

 coast of Clare, where the sea readily carries away the 

 thickly jointed shales and grits of the coal measures ; 

 while on account of the horizontally of the bedding, 

 the rocks can stand with a vertical face, as if they 

 were blocks of masonry in a wall. On the west 

 coast of the Arran Isles, G-alway Bay, the sea has 

 formed peculiar cliffs, and as these have been 

 examined in detail, they may be described. 



From the N.E. shores of the Arran Islands the 

 land rises in a series of eight cliffs, or huge steps, 

 which form continuous terraces, while from the 

 summit of the island there is a gradual fall south- 



