240 STRUCTURE AND MODE OP ACTION 



fissured crust of the globe may have favoured, perhaps for 

 centuries, the growth of palms and tree-ferns and the exist- 

 ence of animals requiring a high temperature, over entire 

 countries where now a very different climate prevails. 

 According to this view of things (a view already indi- 

 cated by me in a work entitled " Geological Essay on 

 the Superposition of Bocks in both Hemispheres") the 

 temperature of volcano? would be that of the interior of the 

 earth, and the same cause which, operating through volcanic 

 eruptions, now produces devastating effects, might in primeval 

 ages have clothed the deeply fissured rocks of the newly 

 oxydised earth in every zone with the most luxuriant 

 vegetation. 



If, with a view to explain the distribution of tropical 

 forms whose remains are now discovered buried in northern 

 regions, it should be assumed that the long-haired species 

 of Elephant now found enclosed in ice was originally indi- 

 genous in cold climates, and that forms resembling the same 

 leading type may, as in the case of lions and lynxes, have 

 been able to live in wholly different climates, still this 

 manner of solving the difficulty presented by fossil remains 

 cannot be extended so as to apply to vegetable productions. 

 From reasons with which the study of vegetable physiology 

 makes us acquainted, Palms, Musacese, and arborescent 

 Monocotyledones, are incapable of supporting the deprivation 

 of their appendicular organs which would be caused by the 

 present temperature of our northern regions ; and in the 

 geological problem which we have to examine, it appears to 



