Notes and Comments. 183 



nises no more than one interruption of the continuity of the 

 Ice Age. Lamplugh (1914) speaking from an intimate know- 

 ledge of many large areas of glacial deposits in Ireland, the 

 Isle of Man, Derbyshire, and the East Coast of England, 

 declares himself unable to recognise any break in the succession 

 of more then local value. The present writer has for 25 years 

 held the same opinion, but long reflection upon a series of 

 facts, quite other than those heretofore considered, have con- 

 vinced him of the existence of a very early glaciation in 

 Yorkshire that is separated by an immense interval of time 

 from the stage represented by the York moraines. At the 

 same time he is not prepared to say, or to suggest, that during 

 that interval there was a disappearance of the ice from the 

 regions to the north or that there was anything more than a 

 wide oscillation of the ice margin. The evidence adduced in 

 the preceding section seems indeed to show that, once the 

 Scandinavian ice began to exercise an influence upon the 

 British shores, it never wholly withdrew until the final liberation 

 of the coast of Aberdeenshire.' 



ONE ICE AGE. 



Prof. Kendall concludes, ' The physical evidence of great 

 fluctuations of the ice-margins in England is clear and con- 

 vincing, but the present writer is not prepared to assent to the 

 proposition that these fluctuations were more than local, or 

 that between the successive retreats and readvances of the ice, 

 there was a complete withdrawal of the ice-sheets back to the 

 very sources. At one time it was considered sulficient to 

 point to a bed of sand or gravel interpolated between two 

 sheets of boulder-clay to demonstrate an interglacial period ; 

 now, however, only very large sheets are accepted as proof, 

 yet they do but prove oscillations relatively larger, and not 

 complete withdrawal. Much more of the nature of the proof 

 demanded is, however, available in Yorkshire. While the 

 drift phenomena are preserved in wonderful freshness and 

 completeness in the Cleveland area and the Vale of York — 

 little lake-channels, small but sharp moraines, kettle-holes and 

 like evidences of recent glaciation retaining their features 

 almost unimpaired — outside {;i.e. south of) the great moraine 

 at Escrick the Drift deposits are reduced to a series of small 

 and disconnected patches.' 



BALBY BOULDER CLAY. 



' One of the most remarkable for its situation is that at 

 Crosspool, Sheffield, 223 m. (730 ft.) above sea level, but as 

 evidence of severe and prolonged glaciation, perhaps the patch 

 of boulder-clay at Balby, near Doncaster (53° 42' N.), is the 

 most remarkable. It is about 800 m. (-|-mile) in length and 

 12 m. (40 ft.) thick, and presents the finest nnland section of 



1918 June 1. 



