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Show ~ . o 1 5 I ,/ .tiw '",'l'·tlu·r '"''' tltt' ·'1'm ~· uludt ('lilt /Jt' ul"l ut'tlu• /lf·rtiHI ubmr nu·ul~tl ltt'tl TJ,,. 1f'Nt .rubttu•"'!/ril ttl,.,,. ftmr bur drt'fi'rt•nl JIIY•/WI~Itll/ o f tfi,'J ' /uu"/ /w,\' tfllrlll,tf fl11• i 'l' iJt'f'UUIIt/f'l"/l'i_tfi'I' ,J'IIU'I flit' ftiiUIIU'IIt'' mti-IV'IIt<t' rr.rt~ t l/1 IU',Ifalii'' 1"1 ulntr;> X· . ' • .. , • '1' ' PRINCIPLES OF GEOLOGY. CHAPTER I. Changes of the Organic World now in progress-Division of the subject-Examination of the question, Whether Species have a I'eal existence in Nature? -Importance of this question in Geology-Sketch of Lamarck's arguments in favour of the Transmutation of Species, and his conjectures respecting the Origin of existing Animals and Plants-His Theory of the transformation of the Orang Outang into the Human Species. IN our £rst volume we treated of the changes which have taken place in the inorganic world within the historical era, and we must next turn our attention to those now in progress in the animate creation. In examining this class of phenoa mena, we shall treat £rst of the vicissitudes to which species arc subject, and afterwards consider the influence of the powers of vitality in modifying the surface of the earth and the material constituents of its crust. The first of these divisions will lead us, among other topics, to inquire, first, whether species have a real and permanent existence in nature; or whether they are capable, as some naturalists pretend, of being indefinitely modi£ed in the course of a long series of generations? Secondly, whether, if species have a real existence, the individuals composing them have been derived originally from many similar stocks, or each from one only, the descendants of which have spread themselves gradually from a particular point over the habitable lands and waters? Thirdly, how far the duration of each species of animal and plant is limited by its dependance on certain fluctuating and temporary conditions in the state of the animate and inanimate VoL, II, B 0 |
