. V. ARRANGEMENT. 185 



HELMIKTHOLITHUS 

 ENTOMOLITHUS 

 PHYTOLITHUS, &c. &c. vide 



Linn. Syst. Nat. Wolsterdorf. Syst. Min. 



Cartlieuser. Min. &c. 



The artificial genera are those which are founded 

 on the detached parts of the original plants or ani- 

 mals, or on the mode in which the organic form has 

 been preserved. (. III. Mode. p. 39.) e.g. 



LlTHOXYLUM 

 LlTHOBIBLIUM 



TYPOLITHUS 



INCRUSTATION, &C. &C. vide 



Cartheuser. Min. Vogel. Min. &c. &c. 



Natural genera are to be adopted in an arrange- 

 ment of extraneous fossils Under artificial genera, 

 a species may be separated into parts, and conse- 

 quently will belong to different genera. Or, a spe- 

 cimen may exhibit various modes of formation, and 

 of course may be arranged in different genera- 

 Under natural genera, one species can only belong 

 to one genus. 



In the arrangement of animal reliquia the genera 

 may conveniently be founded on the Linnean Classes 

 of the recent subjects with reference to the part 

 giving the form, as being either an innate or fdbri- 

 cated part of the original f. (. III. A. 63. ) 



f This is an artificial distinction, but will be found a conve- 

 nient one, and by no means subversive of the natural divisions It 



Bb 



