I. 



Hio'h- Level Shellv-Sands and Gravels. 



PROBABLY there is no subject of geological controversy that has 

 provoked more animated discussion than the shelly-sands and 

 gravels, found in various localities in the British Isles and Ireland, at 

 levels ranging up to about 1,400 feet above sea-level. The question 

 that excites geologists is the same that is reported to have troubled 

 George the Third respecting the apples in the dumpling — how they 

 got there. Having received a cordial invitation from the Editor of 

 Natural Science to unburden myself on this topic, I gladly avail 

 myself of the opportunity. 



And here I am met with my first difficulty. I shall, in the course 

 of this article, have to call these deposits High-Level Glacial Drift, 

 which I suppose is begging the question, as their diluvial origin is 

 stoutly and ingeniously contended for by no less an authority than 

 Sir Henry Howorth, However, as I simply adopt the name that 

 these sands and gravels are generally known by, I hope I may receive 

 absolution. 



Among working geologists of the present day only two explana- 

 tions are offered as possible. 



The older one, which passed unchallenged for over a quarter of 

 a century, is that these shelly-sands and gravels were laid down when 

 the relative levels of land and sea were different to what they are 

 now, and postulates a subsidence of the land or rise of the sea, known 

 as " the Great Submergence." 



The newer hypothesis adopted by geologists who lind various 

 difficulties which they think are unexplained by the submergence 

 theory, is that the high-level shelly drift is sea-bottom, not in situ, but 

 carried up to its present position frozen in the sole of a glacier, or 

 pushed up in front of it while advancing from Scotland over the bed 

 of the Irish Sea. 



It is difficult to give the precise details of how it is conceived 

 this operation was carried on, as I have never yet been fortunate 

 enough to meet with much more than a general statement, but one 

 hypothesis is that the sands and gravels were released from their 

 icy matrix by the sudden melting of the ice at the close of the 

 Glacial Period, hence the rounding of the stones and the false- 

 bedding of the deposits. 



