134 C O N G H O L O G Y. 



vr ix w -vs tis- ix 



SECTION VL 



AS I have now finifhed the general 

 parts of the fludy, I Ihall regular- 

 ly proceed to my lyftem or method of 

 Shells ; but, previous to it, muft make 

 fome obfervations, 



Firft, I do not think it neceffary to di- 

 vide Shells, as Lifter, Gualtieri, Argea«- 

 ville, and others have done, into land, river, 

 andfea Shells. I really do not find eflential 

 characters enough between thofe Shells to 

 pofitively or definitely determine which 

 are which. Some have pretended to efta- 

 blifh a chara6ler between them, from the 

 extreme thinnefs of land and river Shells to 

 fea Shells ; and the want of colour in the 

 land and river Shells. But they are no fixed 

 charaders ; for numbers of fea Shells arc 



ais 



