ORYCTOLOG1T. 



Comprising' every mineral substance dug 

 out of the earth, it was thought necessary 

 to distinguish these by the term adventi- 

 tious or extraneous. To this generally 

 adopted mode of distinction, Mr. Parkin- 

 sou (Organic Remains, vol. i. p. 34,) ob- 

 jects. 



The term extraneous, he observes, de- 

 notes that the substance spoken of is fo- 

 reign to the region in which it is found; 

 a sense in which, he thinks, it cannot, 

 with propriety, be applied to such bo- 

 dies as are almost deprived, not only of 

 their primitive form, but of their original 

 constituent principles. In these cases, 

 where so considerable a degree of na- 

 turalization, as it were, lias taken place, 

 the substance, he conceives, can no long- 

 er merit an epithet implying their being 

 foreign to the regions in which they are 

 found. Instances of the impropriety of 

 this employment of the term he instances 

 in such of the jaspers and semiopals as 

 have derived their origin from wood ; to 

 which the epithet of extraneous does not 

 appear to be strictly applicable. The 

 term adventitious, as implying the result 

 of chance or accident, he thinks ought 

 never to be applied to these substances ; 

 since, in all nature's works, there exist 

 not stronger proofs of the provident de- 

 sign of the Almighty Creator, than in the 

 apparently casual disposition of these sub- 

 stances. To the term petrifaction he ob- 

 jects, because a conversion into stone on- 

 ly is here expressed ; whereas, in many 

 instances, the substances of which the 

 fossil is composed differs as much from 

 stone, as from the matter of which the 

 body was originally composed. Fossils 

 he considers as of two kinds, primary and 

 secondary ; among the former he places 

 those bodies which appear to have been, 

 tib initio, the natives of the subterranean 

 regions : " and under the latter he disposes 

 those substances, which, though now sub- 

 jects of the mineral kingdom, bear indu- 

 bitable marks of having been originally 

 either of an animal or vegetable nature. 

 The term fossil, however, which implies 

 that the organized substance under ex- 

 amination has been dug out of the earth, 

 appears to be sufficient, without any ad- 

 junct to express these substances; in- 

 deed this term is warranted to be thus 

 employed by its general acceptation. 



Besides those bodies which, being ac- 

 tually organic remains, deserve to be con- 

 sidered as fossils, (fosiritia, vulgo dicta of 

 Linnzeus ;) other bodies require to be no- 

 ticed, as sometimes serving to illustrate 

 the nature of organised fossils. These 



VOL. V, 



are, impressims, (impressd, Linnaeus ; typo- 

 lithi, Waller) ; Casts, (rediittegrata, Lin- 

 naeus) ; and incrustations, (incnistata, Lin- 

 naeus.) 



Fossils naturally divide into vegetables 

 and animal, according to which of those 

 kingdoms they originally belonged ; those 

 of the vegetable kingdom shall be the 

 first subjects of our inquiry. 



The parts of vegetables confined in 

 subterranean situations suffer, according 

 to circumstances, either a complete reso- 

 lution of composition, the lighter parts be- 

 coming volatilized, whilst the more fixed 

 remain and form the substance which is 

 termed mould (~ humus _) ; or, as is sup- 

 posed by Mr. Parkinson, it passes through 

 another process, which he considers as 

 fermentative, and becomes bituminous. 

 Wood, thus changed, is called lignum 

 fossile bituminosum, surturbrand, and 

 Bovey coal. By the extension of this 

 process, the same author supposed, that 

 the substances termed bitumens, (naph- 

 tha, petroleum, and asphaltum), are form- 

 ed. To the same process he also attri- 

 butes the formation of amber, of which 

 however no proof appears. That jet, 

 cannel coal, and the common coal em- 

 ployed in domestic uses, have had a vege-* 

 table origin, is rendered highly probable, 

 from the frequency with which they mani- 

 fest the impressions of various vegetable 

 bodies. 



Thus, perhaps, the formation of the 

 bituminous fossils may be satisfactorily 

 explained : but by far the greater num- 

 ber of vegetable fossils are of a lapide- 

 ous nature, and necessarily owe their for- 

 mation to very different processes ; which 

 the same author supposes are, in gene- 

 ral, preceded by the process by which 

 bitumen is formed. Many bodies which 

 are evidently of vegetable origin may be 

 now found existing in a lapicleous, either 

 calcareous or silicious, state ; and many 

 others are found possessing certain marks 

 of the presence of some metallic sub- 

 stance. 



To explain these formations, various 

 opinions have been formed. Some have 

 supposed the injection of the impregnat- 

 ing matter, in a state of fluidity, by igni- 

 tion ; whilst others have imagined the 

 gradual abstraction of the original parti- 

 cles of the body, and the regular depo- 

 sition of the impregnating particles in the 

 spaces which have just been left by the 

 original matter. Mr. Parkinson, who 

 does not admit of this substitution, attri- 

 butes the formation of this description of 

 fossils to the impregnation of vegetable 



