326 JAMES GEIKIE 



cisms go wide of the mark; he has failed to meet my argument, 

 and I have nothing to modify or withdraw. Under these circum- 

 stances I might well leave what I have already written on the 

 subject, and simply appeal to it as a sufficient reply to Dr. Keil- 

 hack. Silence on my part, however, might be misunderstood, 

 and I would not appear to be discourteous to a geologist whom 

 I highly esteem, and whose work no one can value more than 

 myself. At the risk of being tedious, therefore, I shall again 

 shortly state my reasons for the faith that is in me, and take due 

 note of my critic's objections. 



It was while studying certain glacial phenomena in Britain 

 that I was first led to inquire more fully into the grounds upon 

 which German geologists base their belief that the terminal 

 moraines of the Baltic Ridge were deposited during the retreat of 

 the third ice-sheet (Polandian). The evidence which impressed 

 me in Britain may be very shortly outlined. We have two well- 

 recognized bowlder clays developed in the low grounds of our 

 country — the lower of which belongs to the epoch of maximum 

 glaciation (Saxonian), at which time the British and Scandina- 

 vian ice-sheets were coalescent. The upper bowlder clay is the 

 ground-moraine of a less extensive, but still immense, ice-sheet, 

 which, like its predecessor, also occupied the basin of the North 

 Sea, so that continuous inland ice extended as before between 

 Norway and Britain. During the formation of the lower bowlder 

 clay the Scandinavian ice invaded East Anglia and the midlands 

 of England, but this invasion was not repeated by the succeeding 

 ice-sheet. Nevertheless, we have no doubt that the British and 

 Scandinavian ice-sheets were again confluent. Along the whole 

 eastern seaboard of Britain, from Flamborough Head to the 

 extreme north of the Scottish mainland — a region over which 

 the upper bowlder clay is strongly developed — all the evidence 

 indicates that the British ice, underneath which that clay accu- 

 mulated, was steadily deflected to right and left as it passed 

 outwards into the North Sea basin. North of the Firth of Forth 

 the trend of all the stones in the upper bowlder clay, as well as 

 the direction of drumlins, of roches moutonnees and striae are 



