182 . V. PRINCIPLES OF 



PRINCIPLES OF ARRANGEMENT, 



The arrangements hitherto proposed in systems 

 of extraneous fossils have been drawn from two 

 sources : the originals, and the constituent sub- 

 stances of these bodies. The first mode., which 

 takes for its principle of distribution into orders, 

 genera, &c. the kind of animal or plant,, preserved 

 or represented,, is the one which Linnreus has 

 adopted f The other method, founded on the 

 constituent materials, was first proposed by Cron- 

 stedtff Of these two modes of arrangement, it ap- 

 pears almost needless to observe, that the first is to 

 be preferred whether we consider the study, as 

 distinct from that of Mineralogy in general, or as 

 forming a part of that science. In either case the 



of extraneous fossils, though necessary to be known by the col- 

 lector of these bodies. 



t Also Bromel, Wallerius, Woltersdorf, Cartheuser, Vogel, and 

 most other writers who have treated systematically of extraneous 

 fossils. 



tf Afterwards adopted by Bergman. We have not noticed 

 above the mode of extraneous fossils, as one of the principles 

 adopted in their arrangements For though it has been used in 

 conjunction with those we mention, it has never been taken alone, 

 as the foundation of any system. 



