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A WALK ALONG THE GLACIAL CLIFFS OF 



KILLINEY BAY. 



BY PROFESSOR W. J. SOEEAS, EE-D., F.R.S. 



A week before Christmas Mr. Praeger and I found ourselves 

 starting for a ramble along the shore from Bray to Dalkey. 

 A sunshiny day, with sun and clouds making one glory over 

 the headland of Bray behind us, and another over the shining 

 hills of Dalkey in front. The open sea, with its waves break- 

 ing in creaming foam upon the strand, made us think for very 

 contrast of Archangel and its ice-bound port, while the open 

 sky, with mere remnants of riven clouds, turned our thoughts 

 to London, with its sad and mournful canopy of smoke : and 

 we were thankful ; so, for our climate, a Dublin geologist 

 should ever be, but especially on a Sunday afternoon. 



We scrambled over the clean -washed pebbles of the piled-up 

 beach by the mouth of Bray River, finding much of interest 

 and beauty in them, and so reached the low line of cliffs which 

 extends nearly all the way from Bray to Dalkey. The change 

 from the pebbles to the cliff-foot is marked, for the latter is 

 formed of a stiff resistant reddish clay on which walking is 

 sure and easy. This is the famous boulder clay, and in the 

 cliffs before us it can be traced upwards for 12 feet at least ; it 

 is succeeded by a marvellously irregular patchy series of sand 

 and gravel, which we may call "contorted drift," and this is 

 followed by coarser beds more horizontal and more regular, 

 full of great blocks of stone ; these we shall call for the nonce 

 " gravelly boulder beds." Thus in descending order we have 

 the following succession : — 



Gravelly Boulder Beds. 



Contorted Drift. 



Boulder Clay. 

 The distinction between these different deposits looks much 

 clearer on paper than it is in reality ; as one walks along the 

 shore the cliffs seem to change in structure every few hundred 

 yards ; in one place the threefold division can be recognised at 

 a glance ; in another only two divisions are to be distinguished, 

 the boulder beds and contorted drift then forming a single 

 series of sands, gravels, and boulders ; in other places thick beds 

 of pebbles and sands sub-divide the boulder clay into several 



