i II. RELICS, Origin. 15 



plants and animals, introduced by different processes 

 of nature, into the mineral kingdom. (. II. 1.) 



B. 7. Petrificata owe their form to organized 

 bodies ; their substance they derive generally from 

 minerals. (. IL 2. ) ) 



t The origin of extraneous fossils, particularly of petrifactions, 

 has afforded a subject for much speculation among the learned. 

 About the beginning of the last century, the writings of our English 

 naturalists were filled with disputes and contradictory opinions on 

 this head; many esteeming these productions to be mere lusns 

 not ura, while -others ascribed their formation to an imaginary 

 plastic power of the earth, by which, it was contended, stojtes 

 and other fossil substances, with the regular form of animals 

 and vegetables, might be generated. Another singular theory of 

 the tune, proposed to explain the origin of these bodies, was that of 

 the learned and ingenious Lhwyd, who supposed extraneous fossils 

 to be generated by seeds and spawn taken up in vapour, 

 and, after being precipitated in rain, deposited by the percolat- 

 ing water in the crevices and fissures of the earth. Here, 

 according to the hypothesis, meeting with a proper matrix, the 

 seminal particles gradually expand, and produce fossil bodies, in 

 form resembling the parent animals or vegetables. (Luidii Litliop. 

 Brit. p. 136.) In opposition, however, to such futile opinions, 

 several philosophers of the period above alluded to, main- 

 tained, that formed stones (as this class of fossils was then ge- 

 nerally called) were real organic bodies petrified; or, at least, 

 stones moulded in cavities previously filled by animal or vegetable 

 matter a position now fully established, by the multiplied obser- 

 vations of succeeding naturalists. For the controversy on this sub- 

 ject, vide the works of Ray, Hook, Lhwyd, Woodward, Lister 

 Plott, Morton, Leigh, &c. &c. 



