THE PHYSICAL GEOLOGY OF THE NEIGHBOURHOOD 



OF DUBLIN. 



BY 



REV. MAXWELL H. CLOSE, F.G.S., 

 With a Map, 



[Read February 18th, 1878.] 



The following account of the Physical Geology of the country 

 around Dublin has been drawn -up, principally from the Maps 

 and accompanying explanations (Nos. 102, 112, and 121) .pub- 

 lished by the Irish Geological Survey, from papers in the Jour- 

 nal of the Royal Geological Society of Ireland, in the Transac- 

 tions and Proceedings of the Royal Irish Academy, and from 

 the Journal of the Geological Society of London. For further 

 information on the subject the reader may have recourse to the 

 memoirs above named, to the late Professor Jukes' " Manual of 

 Geology," to Professor Hull's " Physical Geology and Geography 

 of Ireland," and to Mr. G. H." Kinahan's " Manual of the Geology 

 of Ireland." 



The immediate vicinity of Dublin is low-lying ground and 

 was formerly called Sean Mdgh Ealta Edaiv, i.e., The ancient 

 plain of the flocks of Edar. It is part of the Carboniferous 

 Limestone plain which so largely occupies the central region of 

 Ireland, and which only reaches the coast in a few places, as near 

 Dublin. On the south side of Dublin the older rocks emerge 

 from beneath the Limestone and rise to form the hill country of 

 S. Dublin, Wicklow, and Wexford counties. Northward of Dub- 

 lin Bay there are isolated exposures of the older rocks in the Hill 

 of Howth, the islands of Ireland's Eye and Lambay, on the ad- 

 joining coast at Portrane, and in the country around Balbriggan. 



The following are the formations which present themselves 

 within the district now to be described, viz., Cambrian, Lower 

 Silurian, Old Red Sandstone (?), Carboniferous Limestone, Upper 

 Carboniferous Shales (Yoredale), Granite and other igneous rocks, 

 and Pleistocene Drifts, 



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