Coffey and Praeger — The Antrim Raised Beach. 145 



as correlating recent geological changes with the history of the human 

 habitation of the district. This evidence was not required in order 

 to establish the claim of the Government to the gold ornaments in 

 question ; nor, indeed, did a court of law present a favourable oppor- 

 tunity for a discussion of such questions, which pertains rather to the 

 work of this Academy. In the present paper we deal, so far as is at 

 present possible, with the post-Glacial movements of submergence 

 and emergence, and the contemporaneous human history of north- 

 eastern Ireland. 



GEOLOGY. 



Desckiptive Geology of the District. 



It has been long recognized by geologists that around the coast of 

 the north-east of Ireland a well-marked shelf or terrace exists, the 

 formation of which, though geologically very recent, is, measured by 

 the standard of human history, of considerable antiquity. This terrace 

 or raised beach is the most conspicuous of a number of geological 

 features which prove that since the close of the Glacial Period, fluctua- 

 tions in the relative level of sea and land have taken place. The 

 geological evidence which can be brought together to throw light on 

 the extent, duration, and date of these changes, ranges itself cliiefly 

 under two heads — (1) phenomena of erosion, (2) phenomena of 

 deposition. In other words, the sea has been continually eating into 

 the land, and depositing the excavated material elsewhere. 



Were the relative level of sea and land permanent, erosion 

 would proceed slowly and steadily. But as this relative level is 

 subject to gradual changes, relative depression of the land is con- 

 stantly exposing fresh surfaces to the action of the waves, while 

 relative elevation of the land is laying bare the flat surfaces 

 Avhich former waves have levelled, and the beds of gravel, sand, or 

 mud which they have laid down. Evidence of emergence of the land, 

 then, may be looked for in — 



(1) . Escarpments now above tide-level (cliffs, banks, caves, &c.). 



(2) . Plains of marine denudation. 



(3) . Marine deposits now above tide-level. 



Evidence of submergence is chiefly to be sought in the occuiTence 

 of terrestrial deposits now below sea-level ; shallow-water deposits 

 now in deep water or at deep level; and in the extension of valleys 

 beneath the sen. 



