G. H. Kinahan — Re-arranged Glacial Drift. 171 



Some of the islands were rocky masses or rocky detritus, while 

 many of them, especially those to the south-east, were composed 

 wholly of glacial drift. During the " Esker sea period " the islands, 

 wholly or partly formed of drift, were more or less denuded, some 

 being totally submerged, while others, when the land finally began to 

 rise again, were bounded by drift cliffs of a greater or less height. 

 During the progress of the denudation of these islands various layers 

 and beds of re-arranged or Glacialoid drift must have been deposited, 

 interstratified with and graduating into the sands, claj'^s, and marls ; 

 while subsequently to the retreat of the waters the drift cliffs would 

 slip and weather away, forming a drift talus over the other drift, more 

 or less long, according to the nature of the materials that formed the 

 drift cliff (see slcetch, p. 168). The drift in these meteoric slopes would 

 necessarily be very similar to the drift in the original cliffs, being com- 

 posed of the same materials; and if the cliffs consisted of glacial drift, 

 the meteoric talus would be almost undistinguishable from glacial 

 drift : yet of course it could not be so classed, as it had been re-arranged 

 by meteoric action, and would be more or less stratified, while typical 

 glacial drift is unstratified. In some of the valleys of the Carlow 

 Hills, Glacialoid drift, due to meteorio action, is found extending in 

 thin sheets for over 100 yards on to recent peat, so that the turf-cutters 

 have to clear away from one to twelve inches in thickness of drift 

 before they come to the peat; yet this "clearing" graduates into a 

 drift that would by many be called glacial. Some of the re-arranged 

 drifts, capping the shelly drift of the co. Wexford, are typical 

 Glacialoid drift ; but others which have covered them to a consider- 

 able depth, and now extend a long way over them, are similar, ex- 

 cept that they are stratified, to the peculiar drift made up of rock 

 detritus so common in parts of Waterford, Kilkenny, and other 

 places in Ireland. This kind of drift ' forms in places high sea-cliffs; 

 and if such cliffs were exposed to much meteoric abrasion, they would 

 form longer slopes than the weathering of tyj)ical glacial drift. When 

 this class of drift overlies the marl in the vicinity of the hills that 

 during the Esker sea period must have been islands, there are often, at 

 the height of a few feet above the marl, lenticular sheets of a brecciated 

 drift, locally called " rubble beds," made up of angular blocks from 

 six to twelve, or even eighteen or twenty-four inches long, similar 

 to the shoreformation found in the recent marine depositions close to 

 the base of some sea-cliffs. This breccia ranges from a few inches 



Ireland and the Silurians and granites to the east of it there are ample materials for 

 the formation of the Wexford marls, in which you will find, though rarely, limestone 

 pebbles. I always looked on these marls as the deep-water representatives of the 

 limestone [Esker] gravels which choked up all the valleys through the mountains to 

 the west and north-west, while the marls and clays were deposited in the shelter of 

 the latter." 



1 This peculiar drift is often similar in aspect to the '- foundation " or " broken 

 shelf" (of the miner), made up of the underlying rock debris, found in many places 

 between the typical glacial drift and the solid rock. In Tyrone, Londonderry, Gal- 

 way, and many other places, it lies between the glacial drift and the rock, and is 

 of inconsiderable thickness; but in some of the southern counties it is of a great 

 thickness, and unassociated with any typical glacial drift. The rocks under it I have 

 never found to be ice-dressed. 



