chap. xti. of Cone hifer oils Deposits. 421 



I have been led to conclude that the bed of the sea has 

 gone on slowly sinking within the present era, over truly 

 vast areas : this, indeed, is in itself probable, from the 

 simple fact of the rising areas having been so large. In 

 South America we have distinct evidence that at nearly 

 the same tertiary period, the bed of the sea off parts of 

 the coast of Chile and off Patagonia was sinking, though 

 these regions are very remote from each other. If, 

 then, it holds good, as a general rule, that in the same 

 quarter of the globe the earth's crust tends to sink and 

 rise contemporaneously over vast spaces, we can at 

 once see, that we have at distant points, at the same 

 period, those very conditions which appear to be re- 

 quisite for the accumulation of fossiliferous masses of 

 sufficient extension, thickness, and hardness, to resist 

 denudation, and consequently to last unto an epoch 

 distant in futurity. 1 



1 Professor Forbes has some admirable remarks on this subject, 

 in his ' Report on the Shells of the iEgean Sea.' In a letter to Mr. 

 Maclaren (' Edinburgh New Phil. Journal,' January 1843), I partially 

 entered into this discussion, and endeavoured to show that it was 

 highly improbable, that upraised stolls or barrier^reefs, though of 

 great thickness, should, owing to their small extension or breadth, 

 be preserved to a distant future period. 



