chap. xv. South America. 595 



thrown up in Peru across the bed of a river, and conse- 

 quently after the final elevation of the country above 

 the level of the sea. 



Ascending to the older Tertiary formations, I will 

 not again recapitulate the remarks already given at the 

 end of the Twelfth Chapter, — on their great extent, es- 

 pecially along the shores of the Atlantic — on their anti- 

 quity, perhaps corresponding with that of the Eocene 

 deposits of Europe, — on the almost entire dissimilarity, 

 though the formations are apparently contemporaneous, 

 of the fossils from the eastern and western coasts, as is 

 likewise the case, even in a still more marked degree, 

 with the shells now living in these opposite though 

 approximate seas, — on the climate of this period not 

 having been more tropical than what might have been 

 expected from the latitudes of the places under which 

 the deposits occur • a circumstance rendered well 

 worthy of notice, from the contrast with what is known 

 to have been the case during the older Tertiary periods 

 of Europe, and likewise from the fact of the Southern 

 Hemisphere having suffered at a much later period, 

 apparently at the same time with the Northern Hemi- 

 sphere, a colder or more equable temperature, as shown 

 by the zones formerly affected by ice-action. A Nor will 

 I recapitulate the proofs of the bottom of the sea, both 

 on the eastern and western coast, having subsided 700 

 or 800 feet during this Tertiary period ; the movement 

 having apparently been co-extensive, or nearly co-ex- 

 tensive, with the deposits of this age. Nor will I again 

 give the facts and reasoning on which the proposition 

 was founded, that when the bed of the sea is either 

 stationary or rising, circumstances are far less favour- 

 able than when its level is sinking, to the accumulation 

 of conchiferous deposits of sufficient thickness, exten- 

 sion, and hardness to resist, when upheaved, the 



