Changes in Distnbittiojt of Land and JVatey. 125 



tions of a similar tendency to transfer land and water from east 

 to west, so that a combination of both tendencies would result 

 in a general movement of land from south-east to north-west, 

 and of water from north-east to south-west. 



The investigation of the problem suggested by this general 

 movement of land and water, if it really exists, seems to belong 

 more to the domain of the astronomer than of the student of 

 physical geography, since the transfer of great masses of solid 

 and fluid matter could not, apparently, take place without affect- 

 ing the distribution of terrestrial gravity, the position of the axis 

 of rotation, &c. However, instead of invoking cosmic agencies 

 which sometimes escape the grasp of the most accomplished 

 mathematician, it may be possible to discover causes whose 

 action is more within reach of direct observation, and which 

 may afford a sufficient explanation of the phenomenon above 

 alluded to. 



At the outset it appears, from a comparison of the 

 height of the protuberances or of the depth of the hollows 

 which compose the surface of the solid earth-crust with their 

 lateral extension, that even a slight elevation or depression of 

 portions of that surface, insignificant in amount when contrasted 

 with the diameter of our planet, may produce a considerable 

 change in the distribution of land and water. According to the 

 soundings taken in every part of the ocean, an elevation or depres- 

 sion amounting to 100 fathoms, the eighty-thousandth part of 

 the earth's diameter, would completely change the outlines of the 

 dry land as they are at present laid down in our charts. Great 

 Britain, for example, would either form part of the Continent of 

 Europe, or be reduced to a cluster of small islands rising out of 

 the sea at a great distance from the French coast, formed by 

 the slopes of the Ardennes, the Vosges, and the mountains of 

 Auvergne. It so happens that both events have occurred 

 in the past. The effect which such a change of level must have 



