223 Professor Lindley 07i the Mode of 



consideration of a complex combination of characters, in which 

 the loss of one organ is compensated for by the peculiarities of 

 those which remain ; but from a few isolated and very imperfect 

 data, exclusively afforded by the remains of the organs of vege- 

 tation. In the latter, unfortunately, the modes of organization 

 are not sufficiently varied to enable us to draw any precise con- 

 clusions from their examination ; but, on the contrary, we are 

 often obliged to he satisfied with a general idea only of the na- 

 ture of the object of our inquiry. This is^ perhaps, not attend- 

 ed with so much practical inconvenience as might be expected, 

 in a geological point of view, because the end of science will be 

 sufficiently answered, if we can, in the first place, determine the 

 general characters and affinities of the plants of the former eras ; 

 and, in the second, so exactly classify their fossil remains, as to 

 be able to recognise them, with such precision, as to render them 

 available for the identification of strata. 



It usually happens that the only parts which are capable of 

 being examined in a fossil state, are the internal structure of the 

 stem, and its external surface ; together with the position, divi- 

 sion, outhne, and veining of the leaves. Of these it has never 

 yet happened that any one specimen has afforded the whole ; 

 more frequently it is only two or three of those characters that 

 the botanist can employ. 



Suppose that he has a fragment of the fossil trunk of some 

 unknown tree ; if no trace can be discovered of its exact anato- 

 mical structure, it may be possible, at least, to ascertain whether 

 its wood was deposited in concentric zones, or in a confused man- 

 ner ; in the former case, it would have been Dicotyledonous, or 

 Exogenous, in the latter Monocotyledonous, or Endogenous ; 

 if a transverse section should shew the remains of sinuous un- 

 connected layers, resembling arcs with their ends directed out- 

 wards, of a soHd homogeneous character, and embedded among 

 some softer substances, then it may be considered certain that such 

 a stem belonged to some arborescent Fern. But if the state of 

 a fossil stem will admit of an anatomical examination, it is always 

 desirable that it should be instituted with the assistance of the 

 microscope. Naturalists have shewn the possibility of this be- 

 ing done ; and if it should prove that the condition of fossil re- 

 mains is in general favourable to this kind of examination, more 



