OF FOSSILS. 209 



twccn phyfical caufcs and c.Tc.ls; and main- 

 taincd, with fuch confidence, i's invariable ope- 

 ration and influence, that he prcdtrled, that 

 Come time or other a fpecies of animals (as the 

 zoophyta) would be difcovcrcd, partaking more 

 or lei's of tlie nature of v eatables. The cele- 

 brated Trcnibley us, by the diico very of the Poly, 

 pi, afterwards confnmcd the tru'Ji of this prc- 

 fage. Daily experience alio convinces us of the 

 exiftcncc of fuch a connecting chain in the or- 

 der of natural bodies; ib that, though \vcarc 

 acquainted with fcvcral links finely, yet it nv.iy 

 fee in fcarcc p')fliblc to afccrtain thofethat fliould 

 be immediately united to them. 



xi. Tbs Ncccffitf of a Syjlem in Natural 

 Hijlory. 



As natural bodies may in various ways be 

 rendered ufeful to man, a thorough knowledge 

 of them becomes highly neceflary; and it will, 

 indeed, in general be found, that their utility 

 encreafes in proportion to the extent of that 

 knowledge. T*heir great number and variety 

 require fyflematic arrangement; without which 

 the nccclTary diflinclions could not be made, 

 and which, in fume cafes, where the difference 

 is very minute, would be productive of great in- 

 convenience. 



O 5 xii. Criteria 



