222 GLACIAL GKOLOGY. 



tinental j^eolo^ists as to the extent of lueii oc('iii)ic(l by inland ice dur- 

 ing? the hist j^reat extension of glacier ice in Europe. It is uell known 

 that this latest ice sheet did not overtlow nearly so wide a region as 

 that underneath which the lowest bowlder clay was accumulated. 

 Gerard de (leer has given a summary* of the general results ol)tained 

 by himself and his fellow workers in Sweden and Norway; and these 

 have been sui)i)lemented by the labors of Berendt, Geinitz, Hunchecone, 

 Klockujann, Keilhack, Schroder, Wahnschatte, and others in Germany, 

 and by Sederhohu in Finland, From them we learn that the end- 

 moraines of the ice circle round the southern coasts of Norway, from 

 whence they sweep southeast by east across the province of Got t land 

 in Sweden, passing through the lower ends of Lakes Wener and Wet- 

 ter, while similar moraines mark o\it for us the termimil front of the 

 inland ice m Fiidand at least two parallel frontal moraines passing 

 inland from Hango head on the Gulf of Finland through the southern 

 part of that province to the north of Lake Ladoga. Further northeast 

 than this they have not been traced; but, from some observations by 

 Helmersen, Sederholm thinks it probable that the terminal ice front 

 extended northeast by the north of Lake Onega to the eastei'u shores 

 of the White Sea. Between Sweden and Finland lies the basin of the 

 Baltic, which at the period in question was tilled with ice, tbrming a 

 great Baltic glacier which overflowed the Aland Islands, Gottland and 

 Gland, and which, fanning out as it passed toward the southwest, 

 invaded, on the south side, the Baltic provinces of Germany, while, on 

 the north, it crossed the southern part of Scania in Sweden and the 

 Danish islands to enter upon Jutland. - - - 



The general conclusion arrived at by those who are at present inves- 

 tigating the glacial accumulations of northern Europe may be sum- 

 marized as follows : 



(1) Before the invasion of northern Germany by the inland ice the 

 low grounds bordering on the Baltic were overflowed by a sea which 

 contained a boreal and arctic fauna. These marine conditions are in- 

 dicated l)y the presence, under the lower bowlder clay of more or less 

 well-bedded fossiliferous deposits. On the same horizon occur also beds 

 of sand, containing fresh-water shells, and now and again mammalian 

 remains, some of which imply cold and other temperate climatic condi- 

 tions. .Obviously all these (lei)osits may pertain to one and the same 

 period, or more properly to different stages of the same period— some 

 dating back to a time when the climate was still temperate, while 

 others clearly indicate the prevalence of cold conditions, and are there- 

 fore probably somewhat younger. 



(2) The next geological horizon in ascending order is that w Inch is 

 marked by the " Lower Diluvium "-the glacial and fluvioglacial de- 

 tritus of the great ice-sheet which flowed south to the foot of the Ilarz 

 Mountains. The bowlder clay on this horizon now and again contains 



Zcifschrift d. deutsch. gcoXog. Gcs. Bil. xxxvii, p. 177. 



