58 Prof. N. 0. Eoht—Writi)uj Chalk of Scania, Sweden. 



The differences between the two nioi'aines have elsewhere been 

 fully discussed by the author. He has himself observed in Greenland 

 that, whereas the lower or ' ground '-moraine is characterized by 

 its rounded, often striated stones, and its clayey matrix of a bhiish- 

 grey colour, the upper or ' internal ' moraine, on the other hand, 

 is characterized by its more angular, rarely striated stones, its looser, 

 more gravelly texture, and its weathered aspect due to oxidization 

 during the melting of the ice. And the same difference exists 

 between the two moraines in Germany and Sweden also. In the 

 latter country this difference is just as conspicuous in the northern 

 districts as in the country at the outer margin of the Scandinavian 

 ice-sheet. The chief conclusions to be drawn from this difference 

 may be recapitulated under the following five heads : — 



1. As a rule, both in Germany and in Sweden, the thickness of 

 the ' upper moraine ' is too small and too uniform to represent 

 a separate ice-age, being sometimes a couple of metres, sometimes 

 3 to 4 metres, and only exceptionally attaining a slightly greater 

 thickness. 



2. The ' upper moraine ' enwraps the uneven contours of the 

 underlying deposits, even when these are loose gravels and occur 

 in abrupt ridges and mounds, so that the ' upper moraine ' often 

 reflects rather closely the contours of its underlying floor. No 

 ground-moraine can behave in this manner. 



3. The ' upper moraine ' is less compressed and less coherent 

 than the ground-moraine, because no ice-sheet has passed over it. 

 It contains few stones, and not rai'ely has a more or less definite 

 stratification, which shows that it has to some extent been acted 

 upon by 'water of melting' (Schnehivasser) during its deposition. 

 The few striated stones which it contains have probably been derived 

 from the ' lower moraine.' 



This distinction has frequently been laid stress upon by other 

 authors. James Geikie remarks upon it as follows : " One may 

 note in many cases that the till which overlies interglacial deposits 

 is not infrequently a somewhat looser clay than the generally 

 excessively tough lower till that clings to the rocks underneath. 

 Often, too, the stones and boulders of the overlying till are, as 

 a whole, less well smoothed and striated than those in the boulder- 

 clay below." The latter deposit he calls " unstratified " and the 

 upper '-indistinctly bedded." 



This conspicuous difference also induced Johnstrup to regard the 

 ' upper moraine ' as having been formed in a special vv^ay, viz., by 

 drifting or floe ice. 



4. If the 'upper moraine' had been a separate and distinct 

 ground-moraine originating from a separate ice-sheet, it ought to 

 possess a definite outer limit marking the greatest extension of this 

 ice-sheet. Such a limit has certainly been diligently sought, but 

 it has never been found and will never be found, because it has 

 never existed. 



One of the most striking features in glacial geology is the great 

 terminal moraine of the European ice-sheet, but its importance has- 



