ON THE MOVEMENTS Ol' THE EARTh's CRUST. 345 



tinned to the latest time. Along both sides of the Pacific; Ocean from 

 (>ape Horn to the Aleutian Islands, and opposite to this along the east 

 coast of Asia as far as the Sunda Islands, strike mighty chains asso- 

 ciated with series of volcanoes; and from the Himalaya through the 

 Caucasus, Balkans, Pyrenees, and Atlas a similar series of vast chains 

 stretches through localities wbicli are often volcanic. These highest 

 mountains of the earth are also the youngest; they are still the least 

 affected by the tooth of time.* 



But these strongly folded localities are of small extent in comparison 

 with the other parts of the earth's surface. On both sides of these 

 folds there are great plateaux and plains, (piite or nearly without any 

 l)lications, and on the whole with undisturbed horizontal beds. These 

 are Suess's " tables" {Tafeln). Africa, Western North America, (in the 

 Eastern there are no younger plications than from Carboniferous times,) 

 Brazil, Australia, Arabia, Persia, India, Siberia, and Eussia, are such 

 " tables," in which the crust is much less disturbed. And no doubt the 

 same thing applies to the sea-basins, or at any rate to the greater part 

 of them. 



When the sidere;tl day lengthens, the sea at once adjusts itself to the 

 new conditions. It sinks under the lower, and rises under the higher 

 latitudes. According as the interior pressure upon the crust increases 

 towards the poles, the opposite pressure upon the sea-bottom also in- 

 creases in the same regions, because the sea rises. But the parts not 

 covered by the sea are exposed alone to the increasing pressure from 

 the interior without any exterior counterpressure being developed. 

 Under lower latitudes the same thing takes place. According as the 

 crust increases in weight the sea sinks, and the pressure upon the in- 

 terior increases more rapidly in the continents, where nothing is re- 

 moved, than in the sea, where the level of the water sinks. Therefore 

 I think that the continents are weak points. The sea's movements 

 weaken the effects of the diminishing centrifugal force for all parts 

 covered by the sea, but the pressure acts with undiminished force 

 everywhere on the solid land, both under low and under high latitudes. 

 Whatever the cause may have been that originally determined the dis- 

 tribution of land and sea upon our globo, it seems to me that we may 

 reasonably assume that the sea's mobility is a preservative force, which 

 perhaps has contributed to make the continenis and oceans, broadly 

 speaking, retain their form from the most ancient times until now. 



There is also reason to believe that the continents may yield more 

 easily than the bottom of the deep sea, and that they may rise and sink 

 more readily. And they are also separated from the depths of ocean 

 by lines abounding in volcanoes, lines of weakness, where the connec- 

 tion between the parts of the crusts seems to be weaker than elsewhere. 



* The summary liere given is founded upon Suess's interesting studies in his great 

 work " Antlitz der Erde." 



