26 Examination of Prof. E. Forbes’s Views on the 
their absence from Ireland and Scotland, the reality of the 
point of departure assigned to them. 
The fourth fauna migrated from the north during the 
glacial era, when Scotland, Wales, part of Ireland, and cer- 
tain groups of islands, were surrounded with ice. The sea 
was then much more extended, and the present mountains 
were only islets, on whose sides plants of a subarctic charac- 
ter flourished. When the bottom of the sea was raised up- 
wards, these islets became mountains, a new population of 
vegetables and animals occupied this newly-emerged surface, 
and the plants of the glacial period maintained themselves 
on the upper parts of the mountains. 
In this statement, the skilful English zoologist has not 
taken into account one of the most certain facts relating to 
the quarternary period, or rather he seems to have taken the 
period of ice for that of the arctic fauna; but the phenomenon of 
striz must have been produced at the time of the extensive sup- 
posititious ice, and it is anterior to the arctic flora and fauna. 
The lands were then more elevated than during the existence 
of arctic shells, or a subsidence brought beneath the water 
the strizc and polished surface which had been produced 
above. It is not easy to conceive how vegetables could pro- 
pagate themselves to a distance, either when the whole 
country was under ice or snow, or when a great part of it was 
covered with water. In either case the circumstances must 
have been little favourable to such migrations. Mr Forbes’s 
hypothesis is therefore in contradiction of the most probable 
deductions, namely, that the lands were more elevated dur- 
ing the formation of striz than during the deposition of arctic 
shells, whose elevation results from a third phenomenon, pos- 
terior to the two others ; and there is nothing to prove that, 
since then, the bottom of the sea has been more exposed than 
it is now. 
As the south of Ireland and England, continues the author, 
were not submerged during the glacial period, the three 
other floras might come to these places before, during, or after 
this epoch. The third, which is the most extensive, occupies 
the chalky surface of Kent, a circumstance in other respects 
fortuitous, with regard to the nature of the ground, for it is 
