216 



AL 



[Ch. XL 



extinct or not, will have their nearest living- analogues in hot 

 countries. Many of them will be unrepresented in the colder 

 parts of the globe, not because of their un suitableness to the 

 climate of such regions, but because of the comparative 

 poverty of the fauna and flora of high latitudes. The fact 

 it is said, that the same genus has often species proper to 



the torrid, temperate, and frigid 



strate that it is on species alone that we can rely in ques- 

 tions of climate.* 



The caution here enjoined is by no means to be disregarded 



ur scepticism on tins head may be carried too far. 

 assemblages of existing- species were submitted to a g 

 alist, one of them cominor from arctic, another from h 



If 



perate, and a third from tropical latitudes, he would be able 



om 



groups had been obtained, even though he might never have 

 seen any one of the species before. He would be guided partly 

 by the presence of certain genera and orders, and partly by 

 the absence or feeble representation of others in each group. 

 It is by reasoning of this kind that we are able to arrive 



at conclusions respectin 

 most of the arenera :fnVl n 



temp 



animals differ from those now living, and it must be remem- 



moder 



which a considerable proportion of the species are identical 

 with living ones, we are able to infer from their associates 

 what was the climate of many species an 

 and plants long since extinct. By this 

 comparison, when we are endeavouring to interpret the monu- 

 ments of antecedent epochs, are greatly increased, since it is 

 not merely to the living creation that we can appeal. 



means 



Evidence of float 



yf the White Chalk in 



England, — The homogeneous character of the white chalk or 

 upper portion of the great Cretaceous formation throughout a 

 large part of Europe is now explained by the discovery that 



made 



careous 



ammi 



* Edinburgh New Phil. Jour., 1830. 





i 



^ 







/ 



lt 



» ,' 



! 







i 





I- 



1 



jst.m 



A siff 

 ffiVd far 



■" 





N 





isbi 





mil- 







uproc 



pel 

 1 





p_ 







me 



t 





* 



%t 



k 



be 



m 





•' 





r 



a 



'. it 



4- ... 



til 



Si 



