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On THE DISTRIBUTION oF MosskEs IN GREAT BRITAIN AND 
IRELAND, AS AFFECTING THE GEOGRAPHY AND GEOLOGICAL His- 
TORY OF THE Present Fiona. By J. SuaAw, Esq. 
(Abstract of Paper read before the British Association.) 
After tracing the distribution of those Mosses in Britain which we 
have in common with North America, Arctic America, Boreal Europe, 
Germany, and the shores of the Mediterranean, the author proceeded 
to inquire into the age of our present Flora, Most geologists, he 
said, are now agreed that the Glacial epoch was one of great rigour, 
and that to our islands it brought a complete annihilation of all vege- 
table as well as animal life. Some believe that the glaciation of the 
land did not extend uninterruptedly throughout the whole period, 
but that it was broken up at different times; and speculations, which 
are now attracting much attention, would go far to demonstrate that 
there were alternations of extreme cold and mild temperature. But 
these modifications of previous views do not affect the position that 
from the glacial age we must date the history of the entrance of the 
various plants into our islands, which our flora has in common with 
the floras of Scandinavia, the Arctic and Alpine regions, and the North 
American mountains. 
During the last period of glaciation, the plants would retreat to the 
south; on the return, however, of a mild climate they would com- 
mence to travel northwards and upland ; and thus it has come, that 
the Arctic and Alpine, the sub-Arctic and sub-Alpine floras are all 
but identical. As the temperature increased, the land rose, and at 
length the British seas were emptied ont, and Britain was connected 
with the Continent. The northern floras would then commence to 
enter our latitudes, and in due course the Germanic. 
There was a period when the temperature of Britain was much higher 
than at present. Mr. Watson, in the ‘Cybele Britannica,’ states that 
the trunks of large Pines occur in peat at an elevation of nearly 3000 
feet,—much higher than their present limit, which is 1950 feet. Dr. 
Dickie furnishes similar evidence in his ‘ Botanist’s Guide to Aber- 
deen, Banff, and Kincardine.’ This period of great warmth came on 
probably soon after the time of land connection with Europe, and 
would bring with it a southern flora. How high the land rose in 
Britain above the sea-level we cannot compute; it must have been to 
