Ch. XXXYIIL] CONCLUDING EEMARKS. 781 



yet throughout all these revolutions, and the consequent alternations 

 of local and general climate, animal and vegetable life has been sus- 

 tained. This has been accomplished without violation of the laws 

 now governing the organic creation, whether the succession of living 

 beings has been brought about "By the transmutation- of species, or, as 

 some contend, by the abrupt introduction into the earth from time to 

 time of new plants and animals, each assemblage of new species must 

 have been admirably fitted for the new states of the globe as they 

 arose, or they would not have increased and multiplied and endured 

 for indefinite periods. 



Astronomy has been unable to establish the plurality of habitable 

 worlds throughout space, however favorite 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 so 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. 



The proofs now accumulated of the close analogy between extinct 

 and recent species are such as to leave no doubt on the mind that the 

 same harmony of parts and beauty of contrivance which we admire in 

 the living creation has equally characterized the organic world at 

 remote periods. Thus as we increase our knowledge of the inex- 

 haustible variety displayed in living nature, and admire the infinite 

 wisdom and power which it displays, our admiration is multiplied 

 by the reflection, that it is only the last of a great series of preexist- 

 ino- creations, of which we cannot estimate the number or limit in 

 times past.* 



* See the Author's Anniv. Address to the Geol. Soc, 1837. Proceedings G. S., 

 vol. ii. p. 520. 



