332 PALAEONTOLOGY. 



to our experience of the power which species of tropical generic types, 

 of both plants and animals, have of not merely existing but flourishing 

 in mild and equable climates— has tended to remove more and more the 

 necessity for reference to a hypothetical change in the system of nature, 

 in order to their intelligible explanation of the presence of fossil remains 

 of a tropical physiognomy in one set of strata, or of those of an arctic 

 character in another, both of which evidences abound in England, and 

 testify to the range of change to which the climate of this now tem- 

 perate latitude has, from whatever cause, been subject. 



As to the igneous, expansive, upheaving cause of geological phenomena, 

 Hunter, while admitting it into his category of geological forces, places 

 it on a lower rank than the aqueous. Yet he duly appreciated and 

 finely illustrated its power and scope of operation. And in this he 

 rises above his contemporary, and some subsequent, geologists, who, 

 though applying their intellectual powers exclusively to this branch of 

 science, were unable to expand their minds to the reception of the 

 evidences of the different kinds of dynamics that had acted, and were 

 still acting, upon the earth, but ranged themselves into one or other of 

 the rival factions of the ' Vulcanists' and ' Neptunists :' either contend- 

 ing, with Werner, that water alone had brought about the actual con- 

 dition of the' earth's surface, or, with Playfair, referring it as exclusively 

 to the operation of fire. 



Hunter admits the efficacy of the latter expansive, sitbterranean 

 force, in " breaking the surface of the earth considerably, probably de- 

 stroying the old and forming the new : — in separating lands formerly 

 united, of which possible examples he cites — the straits of Dover and 

 Gibraltar, and that which now divides the Isle of Wight from the 

 opposite coast of England :" as " raising up a considerable extent of the 

 surface of the earth, which is already formed," or " raising islands in 

 the sea, and afterwards increasing their height by scattering inflamed 

 matter on their surface ;" thus " exposing mineral substances rather than 



forming them They may answer," he philosophically remarks, 



" some material purpose in the natural economy of the earth ; but it 

 does not appear so systematic — not so much on a general principle." 



No Yulcanist could have more graphically or concisely illustrated the 

 modus operandi of his favourite force, than Hunter does in the few 

 pregnant sentences and instances above quoted. 



And, in reference to the effect of igneous agency in upraising a con- 

 siderable extent of the already formed surface of the earth, I cannot 

 refrain here from adducing one of the many recorded instances of this 

 geological operation which has taken place since the time of Hunter. 



In 1822 the coast of Chili was raised by an earthquake, the shock 



