70 . III. DIST. CHAR. Form. 



Form or Structure. (Forma.} 



The form or structure of an extraneous fossil 

 includes the whole of its configuration 



This it either essential or accidental. 



A. 33. THE ESSENTIAL FORM (Forma 

 esstntialis} is the configuration received from that 

 structure which distinguished the original organic 

 body and is either external or internal. 



ginal, appears not to have reached the outer integument, nor to 

 have remained empty for any considerable space of time, the stony 

 substance of the nucleus having been introduced, seemingly, while 

 the organic body was still in a soft and decaying state And hence, 

 the gradual incorporation of the native mineral matter with that 

 of the original ; and, of course, the want of that regular se- 

 paration, which usually takes place between the nucleus and the 

 inclosing reliquium. 



As a conclusion to the remarks we have made on the Modes of 

 extraneous fossils, it may not be improper to state those enume- 

 rated and defined by Linnceus. 



" Petrificata quadruplici modo communiter evadunt : 



1. Fossilia dicuntur Lithophyta aut Testacea, quae diutius in 

 terra latuere immutata, tantum ab elementis parum quasi tfalcinata, 

 glutine orbata, sicciora, fragiliora, nee lapidi immersa. 



2. Redintegrata sunt Petrificata, quorum Animalia cortice du- 

 riore obtecta, intra terram sepulta et arete compressa, demum in- 

 teriore praesertim substantia consumpta, reliquere cavitatem, quam 

 rcplevit vel terra tenuissima ab aqua allata, aut crystalliiatio, ut 

 cvaserit solida interne, externe vero servaverit propriam f guram. 



