222 GLACIAL GEOLOGY. 



tiuental geologists as to the extent of area occupied by inland ice dur- 

 ing tbe last great extension of glacier ice in Europe. It is well known 

 that tbis latest ice-sbeet did not overflow nearly so wide a region as 

 tbat underneatb wbicb Ibe lowest bowlder clay was accumulated. 

 Geiard de Geer has given a summary* of tbe general results obtained 

 by bimself and his fellow- workers in Sweden aiul Norway; and these 

 have been supplemented by the labors of Berendt, Geinitz, Huncbecone, 

 Klockmann, Keilhack, Scbrikler, Wabnschafle.aud others in Germany, 

 and by Sederbolm in Finland. From them we learn that the end- 

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

 whence they sweep southeast by east across the province of Guttland 

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

 ter, while similar moraines mark out for us the terminal front of the 

 inland ice in Finland at least two parallel frontal moraines passing 

 inland from Hango head on tbe 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, Sederbolm thinks it probable tbat tbe terminal ice front 

 extended northeast by the north of Lake Onega to tbe eastern shores 

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

 Baltic, which at tbe period in question was filled with ice, forming a 

 great Baltic glacier which overflowed tbe Aland Islands, Gottland and 

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

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

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

 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 by tbe 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 deposits 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) Tbe next geological horizon in ascending order is tbat wbicb is 

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

 tritus of tbe great ice-sbeet which flowed south to tbe foot of tbe Barz 

 Mountains. Tbe bowlder clay on tbis horizon now and again contains 



* Zeitschrlft d. deutsch. geolog. Gee. Bd. xxxvii, p. 177. 



