1873.] CAMPBELL — GLACIATION OF IRELAND. 205 



out to sea. The landward sides of these hills are all rounded, curved, 

 glaciated rock- surfaces, weathered or well-preserved, on which are 

 drift-ridges, sheets of drift, moraines in perfect preservation, and 

 all other marks of glacial action. 



The ice-engine has ceased to work ; but the tool-marks and chips 

 are there about Carrick. 



The seaward sides of these hills are marks of the sea, which is 

 still at work in full power. 



The sea is undermining these hills : they have long been under- 

 mined by the sea ; and one side of Slieve Liag has been removed. 



The highest top is close to the verge of a broken escarpment 

 nearly 2000 feet high, facing the Atlantic. To look up from a boat 

 is to understand the working of the sea upon a coast. At several 

 places at the base of cliffs are beautiful white beaches of hard 

 rounded pebbles arranged in the usual sweeping curves. At high- 

 water-mark these pebbles, driven by all the force of Atlantic waves, 

 have hollowed a groove in hard white quartz rock, some four or five 

 feet high, of varying depth, and parallel to the water-line. The 

 rock-surface is smooth as polish can make it, as smooth as gla- 

 ciated vein-quartz on the other side of the hill ; but the form of this 

 surface is quite different. It is not grooved and striated in parallel 

 directions by stones and mud fast in ice, moving steadily down in 

 one broad continuous sheet ; these surfaces of marine denudation 

 are dinted and pitted, like the rolled stones which rest upon them, 

 with which the sea pelts the rock when a gale is on. I have taken 

 rubbings from many surfaces of this kind, and they are alike every- 

 where. Close to the undermined rocks are rocks which have been 

 undermined so as to break and fall ; and their angular fragments 

 are rolling in the waves, to be made into pebbles for doing more 

 work of the same land. 



Near the place are caves, some hardly begun, others bored into 

 the rock far beyond daylight, with waves at work in them. On the 

 calmest days they make a wild hoarse rattle and murmur as they 

 mine the rock with its own ruins. I could see no faults to account 

 for these grooves, cliffs, and caves. 



Here, then, are two different sets of tool-marks on opposite sides 

 of a hill, both telling the same story of the destruction of rock to 

 the depth of at least 2000 feet by ice and the sea. 



But this sea-cliff is a geological section 2000 feet high, and several 

 miles long, crossing the strike in a curved sweep. A glance at it 

 after looking at the surface inland demonstrates, better than a volume 

 could, that the structure of the rocks of which these mountains are 

 made has little to do with shapes common in Irish and other hills. 

 The vertical fracture breaks through the edges of contorted quartz 

 beds, which are seen meandering and curving in great arches, 

 folds, and bends, right up to the verge of the cliffs and the scarped 

 hill-top. Not one of these well-marked curves corresponds in any 

 degree to the edge of the upper surface. The plane floor cut hori- 

 zontally by the edge of the sea below cuts shear through all curves 



