Drift of the North German Lowland. —Salishury. 305 
“oround moraine landscape’ (Grundmordnenlandschaft), the most 
characteristic feature of which is its ‘‘rapid changes of level’ 
within short distances. This topography is further described as 
follows: ‘‘Between the numberless ridge- and mound-like eleva- 
tions, which are altogether without order in their arrangement, 
_e@ an equal number of depressions, giving to the surface a broken 
aspect. The elevations enclose countless roundish ponds and 
marshes, largely filled with peat and swamp deposits, as well as 
larger and more or less irregular swamps and i This abun- 
= so great 
that upon the maps the till surfaces between them appear almost 
dance of lakes,and marshes is sometimes 
sieve-like.”  (p. 96.) 
The region where the typical ‘‘ground moraine landscape” is 
best exhibited is stated to be along the Baltic ridge (p. 96), with 
which this type of topography appears in general to be intimately 
connected. It would appear from Dr. Wahnschaffe’s description 
(pp. 97-8) that the constitution of the drift where this type of 
topography is developed is more sandy than is common to the 
ground moraine in other regions. The elevations within this Bal- 
tic ridge are said to be composed largely of sand and gravel over 
which there is frequently a layer of till. 
In discussing the origin of the depressions which mark the 
‘‘oround moraine landscape’ Dr. Wahnschatfe follows his usual 
plan of giving the opinions of other geologists as well as his own. 
K. Geinitz would attribute them chiefly to the eddying action of 
waters during the time of the melting of the ice. Against this 
view Dr. Wahnschaffe argues that the depressions were already 
in existence at the time of the deposition of the uppermost layer 
of till, since this lines them and mantles the adjacent elevations. 
He maintains that their origin is therefore earlier in time than 
the melting of the last ice sheet. Upon the topography of the 
‘‘oround moraine landscape” of the Uckermark, Dr. Wahnschaffe 
insists that the waters arising from the melting of the last ice- 
sheet had no considerable influence. In this view he is supported 
by Drs. Keilhack and Schroeder, and their position seems to be 
irrefragable. 
The origin of the topography which has been designated 
‘‘oround moraine landscape” (Grundmorduenlandschaft) has been 
much discussed by those who have had to deal with it. Various 
views concerning its production prevail. Among the factors 
