521 



worlds throughout space, however favourite a subject of conjecture 

 and speculation ; but geology, although it cannot prove that other 

 planets are peopled with appropriate races of living beings, has 

 demonstrated the truth of conclusions scarcely less wonderful, the 

 existence on our own planet of many habitable surfaces, or worlds 

 as they have been called, each distinct in time, and peopled with its 

 peculiar races of aquatic and terrestrial beings. 



Thus as we increase our knowledge of the inexhaustible variety 

 displayed in living nature, and admire the infinite wisdom and 

 power which it displays, our admiration is multiplied by the reflec- 

 tion that it is only the last of a great series of pre-existing crea- 

 tions of which we cannot estimate the number or limit in past time. 

 All geologists will agree with Dr. Buckland, that the most per- 

 fect unity of plan can be traced in the fossil world throughout all 

 the modifications which it has undergone, and that we can carry back 

 our researches distinctly to times antecedent to the existence of 

 man. We can prove that man had a beginning, and that all the 

 species now contemporary with man, and many others which pre- 

 ceded, had also a beginning ; consequently the present state of the 

 organic world has not gone on from all eternity as some philoso- 

 phers had maintained. 



But when conceding the truth of these propositions, I am pre- 

 pared to contest another doctrine which the Professor advocates, 

 namely, that by the aid of geological monuments we can trace back 

 the history of our terraqueous system to times anterior to the first 

 creation of organic beings. If it was reasonable that Hutton should 

 in his time call in question the validity of such a doctrine, whether 

 founded on the absence of organic remains in strata called primary 

 or in granite, still more are we bound, after the numerous facts 

 brought to light by modern geology, to regard the opinion as more 

 than questionable. I observe with pleasure that Dr. Buckland 

 broadly assumes what I have elsewhere termed the metamorphic 

 theory, having stated in his 6th chapter that beds of mud, sand, and 

 gravel, deposited at the bottom of ancient seas, have been converted 

 by heat and other subterranean causes into gneiss, mica slate, horn- 

 blende slate, clay slate, and other crystalline schists. But if this 

 transmutation be assumed, it must also be admitted that the oblite- 

 ration of the organic remains, if present, would naturally have ac- 



