GREAT LAND SLIDES. 71 



many instances afforded by the study of natural phe- 

 nomena which show that the general tendency of 

 Nature is to smooth down excrescences, to gradually 

 lower the level of great mountain ranges, and so 

 efface the evidences of former convulsions. Against 

 this theory there is the supposed gradual upheaval 

 of the coast line, which is thought to have taken place 

 within historic times in some countries but a simple 

 explanation of this phenomenon would seem to be 

 afforded by a possible slight alteration in the level of 

 the ocean which bathes their shores; and the encroach- 

 ment of the sea at other points, which is probably 

 a consequence of the same movement, would be capable 

 of similar explanation. Among the numerous and 

 complicated motions imparted to the earth by the 

 different natural forces (amounting in all, according to 

 the French astronomer Camille Flammarion, to 14 

 distinct movements) and the consequent continual and 

 gradual shifting of the terrestrial axis, it is easily con- 

 ceivable that these slight alterations of the position of 

 the ocean waters might occur. Moreover, the undue 

 accumulation or melting of the Polar ice would of 

 itself be sufficient to affect the general level of the 

 circum-terrestrial sea, to a very appreciable extent. 



Leaving however these great questions to one side, 

 which involve abstruse problems of geological science, 

 capable only of a possible solution, after an exhaustive 

 study of the whole position, by competent specialists, 

 we shall merely advert to the fact that all over the 

 world the division of the land into a system of natural 

 terraces seems to be the rule instead of the exception ; 

 and a section giving the approximate contour of any 

 great continent is generally found to show a series of 



