30<S On Ih'ifisli Drifts (imi the Intcro/iicidl Problem. 



Tm-: I.\ I i;K(iLA( lAi. Prohi.km in the British Islands. 



Let us now consider the application of the Interi^^lacial 

 li\ pothesis to our own land. 



The task of following- up the evolution of Prof. GeiUie's 

 scheme throui^h its varied phases, thouj^h instructive, is very 

 contusing- one might even say irritating — by reason of the 

 continual changes of correlation which its author has sug-gested 

 in sorting out the British drift deposits into this orderly 

 sequence. Our East Coast boulder-clays, for exan-iple, were at 

 one time held to cover four glacial epochs, and their associated 

 gravels to mark three mild interglacial epochs ; and all except 

 the first giaciation were supposed to be represented in the 

 boulder-clays of Lancashire and Cheshire. Then, somewhat 

 vagfuely, it was allowed that perhaps there were only three 

 separate glaciations on the east coast, with a minor episode of 

 recession of the ice-margin ; and the Lancashire and Cheshire 

 boulder-clays were correlated with the two later of these glacial 

 epochs. But subsequently we are reduced in the eastern district 

 to two epochs of giaciation, with one mild interxal, of which 

 the equivalents are all recognised also in the north-west of 

 England. 



While these and other similar changes may show a laudable 

 desire of their author to keep pace with the growth of definite 

 information, I cannot help feeling that they also show the 

 premature character of the whole scheme, and a flexibility in it 

 that justifies suspicion. Moreover, in spite of these frequent 

 changes in the correlation and this local lopping off of glacial 

 and interglacial episodes, we find, with surprise, that the 

 nuniber of separate epochs in the classification has not dimi- 

 nished, but has actually increased, by regrowth in fresh places. 

 This, again, may betoken the inherent vitality of the scheme, in 

 which case it will g^ain strength froni every readjustment ; but 

 it must certainl}- also denote the weakness of its original basis. 



[iMr. LaiTiplugh then proceeds to discuss the 'First Glacial' 

 and 'First Interglacial' Epochs of the proposed classification, 

 which are supposed to be represented in East Anglia, but not 

 in Yorkshire. He next turns to the Yorkshire Drifts]. 



East \'okkshirk Dkikts. 



The Icjng ctifT-sections between tiic llvmiber and the Tees 



constitute one of the best exposiues of lowland drifts in Britain, 



or even in lun'ope. They fortunately include some deposits 



whicli rc'\eal the conditions pri-\ailing in the neighbouring 



Naturalist, 



