. III. DIST. CHAR. Mode. 61 



and argillaceous petrifactions seldom exhibit the in- 

 ternal texture of their originals. 



c. 8. TRANSMUTATION (Transmutatio). In this 

 mode, the mineral matter, substituted in the place 

 of that which was organic, is produced by the reso- 

 lution of the organic body itsdf the dissipation 



of the aqueous and volatile particles, and the loss 

 of the original texture, f being followed by a new 



combination in the remaining principles. The 



substance, thus formed, retaining the external figure 

 of the prototype, by the medium of the impression, 

 made by the animal or vegetable, on the surround- 

 ing matrix. 



Obs. A transmutation, or complete mineral 

 change, may take place, both in animal and vegeta- 

 ble bodies, under various circumstances; but the 

 mode, to which the term is now applied, requires, for 

 its completion, the enclosure of the organic matter 

 by a mineral substance, capable of receiving and re- 

 taining the impression of its external form. In this 

 state, perfectly secluded from the atmospheric air,ff 

 the enclosed body passes through various gradations 

 of change, which, in the end, produce a mineral 

 formation of matter, inflammable or earthy, ac- 

 cording to the nature of the original, and the loss 



t This distinguishes petrifactions by transmutation, from con- 

 servata which have undergone the process of conversion, (v. 3.) 



ff Vide note ff. p. 4.9. on the changes induced in vegetable 

 matter, when in a fossil state. 



