48 TJic Anieriain Geologist. July. i89t. 
Germanv, the Baltic ridge will quite surely be found traceable 
far onward in Russia. If we follow the outline of the country 
Ijearing frequent or abundant lakes, so generally coextensive 
with the late glacial drift and its moraines, whether in North 
America or Europe, we pass from Prussia northeast to the 
X'aldai hills, which are the most prominent elevations in cen- 
tral or western Russia, although at their highest points only 
aloout i,ioo feet above the sea. These hills are described by 
Nikitin as composed of morainic drift. The border of the 
lake-dotted country leads us still forward northeasterly to the 
Arctic ocean near the middle of its Russian coast, somewhat 
east of the White sea. I can not doubt that distinct lines of 
marginal drift will be traced, when carefully looked for, along 
this distance of about 1,300 miles, completing an outline of the 
border of the European ice-sheet when its rapid final melting, 
attended with the formation of great marginal moraines, be- 
gan. 
Along all its course, from the British Isles, across the 
North sea, through Denmark, Germany, and Russia, this 
boundary of the moraine-bearing drift, as in North America, 
lies at a considerable distance back from the drift limits of 
earlier giaciation. It testifies that the conditions under which 
the marginal drift ridges and hills originated, during stages in 
the general retreat of the continental ice-sheet, were depen- 
dent on the great climatic change brought about by the de- 
pression of the ice-covered parts of both continents in the 
Champlain epoch. Then the borders of the ice-sheets, on 
account of their marginal melting, presented steeper slopes 
than before: much of their englacial drift became superglacial; 
and the deposition of the drift at the ice-front, both beneath 
and upon the margin of the waning ice-fields, was promoted 
by vigorous glacial currents, which, however, were surpassed 
by the rapidity of the summer melting. The moraines, in 
their parallel succession, were amassed with only short inter- 
vals of time separating them, as compared with the prolonged 
earlier stages of the Glacial period.* 
*The general conditions of accumulation of marginal moraines are 
discussed in my former papers in the Am. Geologist, XVI, 107-113, 
August, 1895, and XIX, 411-417. June, 1897. For the Baltic ridge. 
German geological opinions of the time and manner of its formation 
have been well given by Dr. Wahnschaffe in his work reviewed by 
Prof. Salisbury in the Am. Geologist, IX, 294-319, May, 1892. 
