On the Phenomena of the Glacial Epoch. 245 



We inay 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, that 

 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 fche 

 British Islands were sunk from 1000 to 1500 feet beneath 



