338 JAMES GEIKIE 



ent plan. He says: "La longueur des lignes representant les 

 glaciations successives est proportionelle aux aires glaciees. Le 

 rapport des aires glaciees aux differentes epoques X, Y, Z, Z^ 

 est presque identique dans le Nord de I'Europe et dans les 

 Alpes, et parait devoir etre exprime par: 0,7 (?): i : 0,66:0,27 

 en moyenne." ' 



If Dr. Keilhack, instead of estimating the extent of the 

 several ice-sheets of northern Europe by drawing lines from the 

 north end of the Gulf of Bothnia into Germany, will contrast 

 the superficial areas of the successive glaciations he will prob- 

 ably come nearer the truth. He will, at all events, ascertain that 

 De Geer's great Baltic Glacier (Mecklenburgian) large though it 

 was, yet covered a much smaller area than that occupied by the 

 preceding Polandian ice-sheet. Nothing could be more absurd 

 than to describe the last great Baltic Glacier as being "little 

 inferior to those of earlier epochs." It was very much inferior, 

 and quite comparable, as Du Pasquier has said, with the Alpine 

 valley-glaciers which are represented in his diagram by the 

 line Z^ 



In correlating the Alpine valley-moraines of Professor Penck's 

 "first postglacial stage" with the terminal moraines of the great 

 Baltic Glacier I was well aware that no interglacial beds had 

 been observed underlying the former. I knew quite well that 

 the valley-moraines in question were generally considered to 

 mark pauses in the retreat of the great glaciers of the inner zone. 

 Latterly, however, Du Pasquier had begun to doubt if such were 

 really the case. Quite recently he had detected evidence to 

 show that the formation of the moraines of the "first post- 

 glacial stage" had been preceded by an interglacial interval of 

 fluviatile or lacustrine accumulation. As Du Pasquier's observa- 

 tions are the first of the kind recorded, I shall quote what he 

 says on the subject : 



Au-dessus de I'etage glaciaire Z (see his diagram) encore deux ou trois 

 systemes de moraines au moins, se terminant vers I'aval en nappes d'allu- 

 vions precedent les moraines actuelles. Ces systemes, tres clairement marques 



' See Bulletin de la Soc. Neuchat. de Geogr., VIII (1894-5). 



