54 The American Geologist. January, 1895 
PrehiHtoric Europe. This also \v;is (lie time of f^roali'st oxtonsion of the 
glaciers in the Alps, P^reiioes, and Caucasus. The ensuing? intcrgiacial 
beds of northern Germany contain remains of a temperate flora and 
fauna, indicating even milder conditions liian those of the present day, 
and the rivers eroded deep valleys. 
3. For the third glacial epoch, ice-sheels covering Ireland, Scot huul, 
northern England, and Wales, are represented as continent with the 
Scandinavian ice-sheet, which reached south to Hamburg. IJerlin and 
Warsaw, and east to the Valdai hills and White sea. During the ne.\t 
epoch of interglacial conditions, the Haltic sea is shown to have had a 
temjM'rate marine fauna, while the adjacent lands of northern (Jermany 
had a corresponding terrestrial fauna and Hora. 
4. In the fourth glacial epoch, or that of the (irrat l>altic glacier, de- 
limited b}' conspicuous moraines, thi' ice-sheet covered nearly all of 
Scandinavia, excepting a considerable tract of southern Sweden; it 
reached (!ast over a large part of Finland, and south along the Baltic 
trough to the lowlands of northern Germany and eastern Denmark; but 
the North sea existed as now, and the British Isles had only local or dis- 
trict ice-sheets of comparatively small extent. The lU'xt interglacial 
epoch had forests of deciduous trees farther north than they now flour- 
ish; and the Baltic was for a time converted into a fresh-water lake, 
named the Ancylus lake from its most characteristic fossil shells, as made 
known by the studies of Baron de Geer and others, but ]at(M' it was con- 
nected with the sea by straits across southern Sweden, admitting a ma- 
rine molluscan fauna of somewhat more temperate character than now. 
While the Baltic was a lake, the bed of the North sea. the English 
channel, and large tracts which are now shallow sea surrounding the 
British Isles, and a belt thence to the Faeroes and Iceland, are mapped 
as land, whereby the European flora was extended to Iceland and Green- 
land. That migration may, however, as the reviewer thinks, be better 
explained otherwise, as stated farther on. 
5. The fifth glacial epoch is represented only by local or valley mo- 
raines in the British Isles, the snow-line iii Scotland having been at an 
average hight of 2,500 feet. 
G. After an interval of forest growth in the mountain valleys, another 
and the final ei)och of local glaciers, occurring only on the highest 
mountains in Scotland, had its snow-line at the hight of ;{,.500 feet. 
Prof. II. I). Salisbury, reviewing this volume in the Journal of Geol- 
ogy (vol. II, pp. 730-747, Oct-Nov., 1894), well notes the remarkable par- 
allelism of the European and North American glacial history, "that the 
outermost border of the drift in Euroju', as in America, is not character- 
ized by terminal moraines; that the limit of the drift deposited during 
the second advance of the ice [Prof, (ieikie's third glacial epoch] in 
EuroiK', as in America, is not commonly markiMl hy well-defined mo- 
raines, though morain'esare not altogether wanting: Iliat the great body 
of loess in Europe, as in America, seems to be connected with the ice 
advance which succeeded the greatest; and that the ice during the next 
succeeding advance (the second ;i fter the greatest ). both in iMirope and 
