On the Phenomena of tlie Glacial E'poch. 245 
We may farther remark, that when we consider the 
means by which the excess of heat in the intertropical 
regions is conveyed to the polar circles, as we find them 
in the existing cosmical arrangements, we are led to con- 
clude that the general temperature of the earth's surface is 
in reality but little affected by the manner in which the 
land and water are distributed over it. The heat commu- 
nicated to the land is carried off by currents of air ; the 
heat communicated to the ocean is carried off by currents 
of water ; and it matters but little what the medium of con- 
veyance may be. If geologists, therefore, are correct in their 
conclusions with regard to the far higher average tempera- 
ture of the earth in the earlier eras, that temperature cannot 
possibly be accounted for by any supposititious change in the 
distribution of land and water. 
While, however, we cannot adopt the hypothesis which 
assumes that a change in the distribution of land and water 
may effect the mean, or average, temperature of the earth, 
and account for the phenomena of the earlier eras, we 
certainly believe that local changes of climate of a very 
remarkable kind may be attributed to that cause. 
We also concur in the opinion, which Sir Charles else- 
where expresses, that the glacial period was not contempora- 
neous all over the globe ; but that, while one part of the 
earth was subjected to extreme cold, other portions in similar 
latitudes enjoyed a genial warmth. 
Having now examined the principles that regulate the 
distribution of the equatorial heat over the globe, and hav- 
ing shown, as we flatter ourselves is the case, that many of 
those changes of temperature which the western parts of 
Europe have undergone may be ascribed to alterations in 
the direction of oceanic currents, we now proceed to in- 
quire if there are any circumstances that lead us to conclude 
that such has really been the case. 
There is one remarkable fact, or rather class of facts, tljat 
confirms our conjecture. All the changes of temperature 
which have occurred in the glacial and more recent epochs 
have been coincident with changes of elevation. When the 
British Islands were sunk from 1000 to 1500 feet beneath 
