8 
Proceedings of the Royal Society of Edinburgh. [Sess. 
Weybourne Crag, which, from the presence of Arctic species among the 
mollusca, point to the advent of cold conditions. No morainic deposits in 
the British Islands can be definitely referred to this stage, but Scandinavia 
nourished an ice-sheet which overflowed Scania, occupied the basin of the 
Baltic, and extended as far south as Hamburg and Berlin. 
The Norfolk Forest-bed series contains the British records of the 
Norfolkian or First Interglacial Epoch. They consist of fresh- water and 
estuarine beds which are supposed to have been laid down when the 
southern part of the North Sea basin was dry land and Britain was joined 
to the continent. The flora points to a temperate climate similar to that 
of Norfolk at the present day. The fauna yields remains of elephants 
( Elephas meridionalis, E. antiquus), hippopotamus, Etruscan rhinoceros, 
deer, bison, the sabre-toothed tiger, and two northern forms, the glutton 
and musk ox. Some of the species are of distinct Pliocene types, and many 
of the large mammals found in the Forest-bed series did not survive that 
stage. The Forest-bed series is overlain by the Leda myalis bed and a 
layer of flood loam with Arctic plants (Salix polaris, Betula nana), indicat- 
ing glacial conditions. 
The Chillesford Clay, the Weybourne Crag, and Norfolk Forest-bed have 
been usually regarded as of Pliocene age by British geologists, but James 
Geikie contended that the temperate flora found in the Forest-bed pointed 
to an oscillation of climate between the overlying Arctic plant zone and the 
underlying Weybourne Crag with its northern species. Hence he regarded 
them as forming stages in his glacial succession. 
On the continent, representatives of the First Interglacial Epoch were 
believed by James Geikie to occur in the Low Countries, France, Germany, 
and Italy. This correlation was based mainly on their mammalian remains, 
which closely resemble those of the Forest-bed series. The interglacial 
fresh-water shell bed, proved in borings near Berlin, are referred to this 
stage. From the descriptions by Wahnschafle it appears that this deposit 
rests in places on boulder clay of considerable depth and is covered by drift. 
The most abundant species is Paludina diluviana, whose present habitat 
is far to the south on the borders of the Black Sea. Among the alluvia 
of the First Interglacial Epoch he grouped the sand beds at Mauer, near 
Heidelberg, which have yielded a lower jaw of early Pleistocene man. He 
admitted that the geological and palaeontological evidence supporting this 
correlation was not quite decisive. 
The Saxonian or Second Glacial Epoch (Mindelian of the Alps) was 
coincident with the maximum glaciation. During this period the ice 
radiating from Scandinavia spread over the northern plains of Europe to 
