6o flic Irish Xalurulist. Apul, 



general drift uf the materials has been fruni the north-west, 

 and they have been swept from the limestone plain far on 

 to the granite mountains. . . . The whole of the phenomena, 

 in mv judgment, points to submergence."^ 



Now is there any such very strong evidence for this 

 theory of an interglacial period with at least one considerable 

 submergence ? There can be no a priori objection to the 

 theory, as in the European Alps the glaciers withdrew more 

 than once during the Glacial period far into the upper 

 valleys of the mountains, and from such undoubtedly inter- 

 glacial deposits as the Hotting breccia there is the evidence 

 that the climate of that interglacial period was rather 

 warmer than that of the present day.^ 



When we examine the deposits of sand and gravel which 

 were supposed to prove the occurrence of an extensive 

 submergence, we find they display none of the well-known 

 characteristics of a sea-beach, with its definite local fauna 

 and with typical shore pebbles, and there is the further 

 difficulty that while the sands and gravels of the Irish 

 Sea basin, with their contained exotic shells and erratics, 

 may be found at levels varying from 1,200 feet to sea-level, 

 their distribution is restricted to definiteh^ limited districts 

 and they are wholly absent from neighbouring areas quite 

 as favourable to the development of marine deposits. So 

 far from the evidence pointing to submergence and depo- 

 sition from drifting ice-bergs, all the evidence in the Irish 

 Sea basin points to the existence of some geological agent 

 sufficiently rigid in its motion and direction to control the 

 distribution of shells and erratics in definite directions and 

 of a sufficiently prolonged existence to have produced such 

 • recent surface features as the Scalp, the Dingle and the 

 Montpelier gap. In many places, however, there appear 

 sections of glacial deposits which tend to support the inter- 

 glacial and submergence theory, and when they had been 

 generalized into diagrams it became correct to accept the 



iT. .Mt'llard Keadc, "The High and Low-level Shelly Drifts around 

 L)ul)lin and P>ray," IrisJi Xafuralisi, vol. iii., p. 132 (189.}). 



''A. IVnek u. V,. Brin kn' 1 , " ] )i,. Aljnn ini liiszeitalter," Band I., pp. 

 }>^y'^S (lyoi-oy). 



