Bulletin 35 



rage 42 



1 'stance connected with it should be carefully observed 

 "and recorded, that researches into the more ancient 

 "formations inay be conducted with greater success ; " * 

 and in addition, it is probable that important inferences 

 with respect to the climate of the earth in former 

 epochs may flow from comparisons such as those at- 

 tempted in the present paper. 



I shall conclude with a few remarks in connexion with 

 the possibility of a colder climate having prevailed in 

 the West Indies during the newer pliocene period. It 

 is known that species of cryptogamous plants found in 

 the arctic regions have been discovered on mountains in 

 the torrid zone. Plants indigenous to Lapland have 

 been observed on the Peak of Teneriffe and on the Blue 

 Mountains in Jamaica. Similar facts have been noticed 

 relative to the Andes. t It remains to be seen how far 

 those phenomena are attributable to the former preva- 

 lence of colder climates over larger portions of the 

 earth's surface. It is possible that the plants referred 

 to may have first appeared within the tropics during a 

 period when the climate was colder than at present, and 

 that when the conditions of temperature become altered 

 these plants receded from the lowlands, ultimately oc- 

 cupying only the higher summits of mountains. There 

 is however nothing to show that the climate of the torrid 

 zone was ever such that ice could have been present in 

 an} 7 great quantity. 



The idea of those alterations in the climate of the 

 earth, which are admitted on all hands to have taken 

 place, having been widely spread, is not now brought 

 forward for the first time, and hypotheses in explanation 

 have been suggested by various observers. There may 

 even have been more than one period of comparative 

 coldness, and the phenomena may have recurred ac- 

 cording to definite and fixed laws. J Again, the climates 

 of the globe might have been such, that while the 

 southern hemisphere was enjoying more than an average 



* Smith, Post-Tertiary Geology, page 5. 

 t Humboldt, Travels, (Bonn's ed. 1852). vol. 1, p. 115. 

 X Page, Past and Present Life of the Globe, p. 190. 



