THE EARTH'S SURFACE SEA ACTION. 47 



the ground is as follows : " Cliff over 250 feet 

 high. Two shale beds ; the cliff rises perpendicular 

 from the highest. These shale beds are supposed to 

 be the continuation of these under terraces, Nos. 

 2 and 3." South of Portmurvy there are from four 

 to six of these sea-terraces, and the cliff is less than 

 50 feet high. South of Gurtnagapple the cliffs are 

 low but perpendicular ; hereabouts, nearly E. and W. 

 master joints occur about two yards apart; and as 

 the sea undermines the cliff, masses of rock, tons in 

 weight, which are disconnected by these joints, topple 

 over and fall, forming a breakwater at the base of the 

 cliff. This breakwater extends for about half a mile. 



At Corker there is a perpendicular cliff formed by 

 E. and W. master joints. In the face of the cliff 

 there are two shale partings about 40 feet asunder, 

 the lower being about 60 feet above half neap tide. 

 They seem to be the representatives of the shales 

 under terraces Nos. 3 and 4. 



The small promontory called Nalhea is bounded by 

 N. 15 E. master joints ; here the shale beds have 

 dipped below the sea level. 



South-east of Nalhea there are four or five sea- 

 terraces at the base of the cliff, and at Whirpeas the 

 cliff is about 140 feet higher than the level of neap 

 tide, a shale bed occurring about 40 feet above that 

 level. To the east of this, at Pollnabriskenagh, the 

 limestones are traversed by E. and W. master joints, 



