146 



Proceed'uigs of the Royal Irhli Acadcmn. 



Erosion FJmiomena. 



The erosion phenomena of the district are well marked. The 

 most striking feature is the steep scarp at some distance from the 

 present beach, and at some height above it, which marks the former 

 encroachment of the waves. This scarp is subtended by a level or 

 slightly sloping plain representing the former beach or sea-bed ; it 

 may be formed either of the older material in which it was cut, or of 

 newer material laid down on the denuded surface by the sea. In the 

 district under consideration, the scarp is frequently cut in the Boulder- 

 clay, which the Glacial Period spread over the low lands ; but often 

 it is formed of much more ancient rocks. This old coast-line, 

 and its accompanying plain of denudation, may be seen admirably 

 displayed at many places in the north-east. In County Down, in the 

 Ards peninsula, it is well developed, as at Cloghey Eay. Here a 

 sandy, grass-grown plain, yielding marine shells, and up to half a mile 

 in breadth, stretches from the present shore-line inland to a series of 

 bold bluffs, over fifty feet in height, cut in the Glacial drift. On one 

 of these, on the extreme edge of the scarp, an earthen tumulus is 

 built, and looks down on Kirkistone Castle, an early seventeenth- 

 century structure, which stands on the old beach below. 



At numerous points round the Antrim coast, the raised beach is 

 well marked. The coast road is built on the old terrace in many 

 places, with the sea on one hand, and the scarp on the other, cut some- 

 times in the drift, sometimes in the basalt or the chalk. At Drains 

 Eay, Carnlough Eay, and elsewhere, the shelf widens, and is formed 

 of beach-gravels, with a scarp of Eoulder-clay rising steeply behind it. 



Nowhere are the features under consideration seen to greater 

 advantage than in the neighbourhood where "the gold ornaments" 

 were found. Here the terrace is very extensive, covering many square 

 miles, and is formed of clays and sands— the old bed of the sea. 

 Edging this is a splendid scarp of Eoulder-clay, distant in places from 

 two to three miles from the natural high-water mark of the present 

 day,^ and 30 to 40. feet in height. To the northward of this 

 plain, beside the road which skirts the low ground, high bluffs of 

 basalt may be seen, the material composing which has slipped down 

 from the hills over the Lias clays, and been finally eroded by the sea 

 during the period with which we are dealing. 



1 Lcind lias been reclaimed here, shutting out the sea from portion of its natural 

 foreshore. 



