G. E. Kinahan—On '•'Middle Gravels" (?), Ireland. 265 



some portion of the low grounds of Scotland. But certainly no 

 English geologist had up to the appearance of Mr. CroU's first 

 paper in the Philosophical Magazine ventured to affirm that the 

 climate of these interglacial periods in this country could be other 

 than cold or sub-arctic. Indeed, the facts then known did not warrant 

 any such conclusion. But the publication of this ingenious theory 

 tended to revolutionize all our preN-ious conceptions on the subject; 

 for, if there was any truth in the hypothesis at all, then the records 

 of mild and even genial interglacial periods might certainly be 

 expected to occur. The former existence of such periods followed 

 no less surely from theory than did that of cold and arctic conditions. 

 Mr. Croll himself had referred to the intermingling of arctic and 

 southern mammalia in the valley-gravels as in favour of his hy- 

 pothesis, an explanation of the facts which. Sir J. Lubbock remarks, at 

 once gets rid of what has always hitherto been considered a diffi- 

 culty. By many English geologists, however, the valley-gravels 

 with extinct mammalia were, and still are, believed to be of postglacial 

 age. Others again, as Mr. Godwin-Austen, are of opinion that these 

 gravels in the south of England are the equivalents of the glacial 

 deposits in the north. But as far as I am aware, no geologist has 

 yet attempted to correlate the river-gravels with undoubted interglacial 

 deposits. I was in hoj)e that ere long some one well acquainted 

 with all that pertains to the superficial deposits of England would ad- 

 dress himself to this task ; for it seems to me that a far deeper signifi- 

 cance attaches to the interglacial deposits of Scotland, Switzerland, 

 and America than has yet been recognized, otherwise their bearing 

 on the phenomena of the English drifts could hardly fail to have 

 attracted more attention. That many of the views entertained in 

 these papers have already occurred to fellow- workers in other fields 

 is extremely likely ; some of the conclusions indeed appear too 

 obvious to have escaped attention. Others again are novel and 

 opposed to prevailing ideas, and these I should like to have dis- 

 cussed at greater length, but I have already covered too many 

 pages of the Magazine. I hope, however, to enter more fully into 

 the whole subject of glacial and interglacial climates in another 

 place. It would extend this paper (already long enough) beyond 

 due limits were I to attempt any summary of the conclusions arrived 

 at in this and preceding papers: the accompanying table (pp. 

 262, 263), however, will show the arrangement of the Quaternary 

 deposits which has been suggested. 



VII. — Middle Gkavels (?), Ireland. 

 By G. H. KiNAHAN, M.E.I.A., etc. 



IN a paper on a comparison of the drift of Ireland with that of 

 Lancashire, the author Prof. Hull states, that he recognized the 

 equivalents of the English beds in the drift clifi"s at Killiney, Co. 

 Dublin,' and in the Geol. Mag. for March, 1872, Mr. J. Geikie has 

 quoted Prof. Hull : I therefore request leave to say a few words 

 about the gravels of Ireland, more especially as Mr. Geikie 

 1 Geol. Mag., Vol. VIII., p. 294. 



