38 



region itself, and carried eastward to the sea. The occur- 

 rence of similar calcareous deposits in the seaward glens 

 and valleys of the Dublin and Wicklow mountains for some 

 miles south, and on their sides to a considerable height, 

 was ascribed to the current of the same deluge, sweeping 

 the transported substances over the lower parts of the moun- 

 tain range, and then turning southwards along the sea coast, 

 after passing the north flank of the mountains. Similar 

 facts, but in an inverted order, from south to north, have 

 been observed towards the southern flank, in the County 

 Wexford. 



It was urged, that the subsiding waters of this inunda- 

 tion, rushing down the valleys, and meeting below with the 

 main current on the plains, would throw up those ridges 

 along the sides of the hills, and on the flats beneath ; of 

 which a remarkable example is presented in the glen of 

 Ballynascorney, (through which the Dodder descends from 

 the Dublin mountains,) and in the gravel hills in front of 

 that, from Tallaght to Crumlin. 



The direction assumed in this paper for the diluvial cur- 

 rent agrees remarkably with that assigned by Professor 

 Phillips, as the cause of the distribution of the Shapfell 

 boulders over the north-east of England. A conjecture 

 was proposed as to the possible occasion of such a move- 

 ment of water over the country. The limestone tract was 

 evidently formed under the sea. Its elevation may have 

 been connected with the last great convulsion, which deter- 

 mined nearly the present form of the surface. Great 

 disturbances are seen at Killiney, the Scalp, &c., to have 

 attended the appearance of the granite, and even to have 

 followed that period, affecting the granite itself. Many 

 parts of the Irish coasts present such abrupt terminations 

 towards the sea, as to indicate either a violent raising of the 

 island from a continuous tract at the bottom, or a sudden 

 sinking of an extent of dry land around the present surface. 



