than the fossil remains of vegetables. In the former, the entire figure 

 of the investiture of the animal is sometimes preserved ; and where 

 this is not the case, sufficient is frequently found, to point out the 

 genus, and in many cases, even the species of the animal : but pieces 

 of wood, leaves, with the kernels and coriaceous coverings of fruits, 

 can seldom do more than lead to uncertain conjecture, respecting the 

 natural order or class under which the plant should be placed. 



It is my intention, whilst proceeding to inform you of the result of 

 my investigations, to continue to place them before you in an episto- 

 lary form. This is indeed rendered necessary, in some degree, by 

 that form having been adopted in the preceding volume. But, inde- 

 pendent of that circumstance, it is the form which, for several other 

 reasons, I am; disposed to prefer. By adopting this mode, I shall feel 

 myself more at liberty to introduce such matter as, although highly 

 useful in illustration, might hardly perhaps be admissible in a work 

 composed according to the more rigid forms, in which disquisitions of 

 this kind are generally presented to the world. The epistolary stile 

 too appears to be well suited to the discussion of subjects of natural 

 history. It allows that familiar mode of expression, which seems to be 

 best calculated for those illustrations which are required by the various 

 topics, which this study embraces. It also admits of the introduction 

 of those reflections, which although, perhaps, not unacceptable, and 

 which naturally arise from the immediate subject of inquiry, might 

 appear to be too digressive, in a work written in a truly systematic 

 form. But another circumstance, it must be admitted, has had some 

 considerable weight in determining this choice. These observations 

 have been put to paper, at short and uncertain periods, when the 

 fatigue arising from professional labours have left the mind in such a 

 state, as to render it necessary to record the results of its investiga- 

 tions, in that familiar kind of stile as might best suit the writer in 

 such moments ; and as might not demand the extreme severity of cri- 

 ticism. 



