22 
Bulletin 35 
170 
I'age ii.2 
“stance connected with it should be carefully observed 
“and recorded, that researches into the more ancient 
“formations ma\- be conducted with greater success ; * 
and in addition, it is probable that imjiortant 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 tiie Peak of Tenerifle 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 po.ssible 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 conditioiis of temperature become altered 
the.se 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 pre.sent in 
any great quantityL 
The idea of tho.se 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 fir.st time, and hyqx)theses 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. 
1 Humboldt, Travels, (Bohn’s ed. 1852). vol. i, p. 115. 
J Page, Past and Present Life of the Globe, p. 190. 
