36 STUDIES, SCIENTIFIC AND SOCIAL chap. 



thousands of feet, rarely exhibit any difference of level on 

 the land surface, owing to the fact that subaerial denuda- 

 tion has kept pace with slow and intermittent elevation. 

 But in the ocean depths no such denudation is going on ; 

 and we can therefore only account for its very uniform 

 surface on the supposition that it is not subject to the 

 varied and complex subterranean movements which have 

 certainly acted within the continental areas throughout 

 all known geological time.^ 



Similar Range of the Gculoyical Record in all the Con- 

 tinents. — There is one other general consideration which 

 indicates the permanence and continuity of the Continental 

 Areas, and which renders it very difficult, if not impossible, 

 to suppose that they have ever changed places with the 

 great oceans. It is, that on all the present continents w^e 

 find either the same or a closely parallel series of geological 

 formations, from the most ancient to the most recent. 

 Not only do we find Palosozoic, Mesozoic, and Cainozoic 

 rocks everywhere present, but, in proportion as the con- 

 tinents are explored geologically, we find a tolerably 

 complete series of the chief formations. From Laurentian 

 to Carboniferous and Permian, from Trias to Cretaceous, 

 and from Eocene to Quaternary, the geological series 

 appears to be fjiirly represented, not in continents only but 

 also to a considerable extent in the large continental 

 islands such as Great Britain and New Zealand. 



Now this is certainly not what we should expect if the 

 present continental areas had, at different epochs, risen 

 out of the deep oceans. In that case some would have 

 commenced their geological history at a later period than 

 others, having either a late Palaeozoic or some Mesozoic 

 formation, or even an early Tertiary for their very lowest 

 stratified rock. Others, which had become oceanic for the 

 first time at a later epoch, would exhibit an enormous gap 

 in the series, either several of the Mesozoic formations, for 

 example, being absent, or some considerable portion of 



^ The Rev. 0. Fisher has arrived at the same conclusion from his 

 own researches. He says: "The compression which has caused the 

 thickening accompanied by corrugation, such as characterises most 

 elevated tracts, is properly a continental phenomenon, and has no 

 analogue beneath the oceans." L.c, p. 253. 



