GENERAL REMARKS. 69 



authorise any inferences as to the comparative vigour of the vegetation of 

 the different epochs ; and in the colder regions of both continents, we have 

 trees at the present day of much larger dimensions than those of any fossil 

 trunk hitherto discovered. 



The prevailing colour of the fossil vegetables, retaining their organic 

 texture, which occur in our mountain-limestone series, coal-fields, and lias 

 deposits, is brown, of various tints, more commonly wood-brown, frequently 

 umber, and sometimes greyish or blackish brown. Those of the lower of 

 these deposits are calcareous, as are generally the fossils of the lias, and the 

 veins by which they are intersected are commonly of calcareous spar. In the 

 coal-formation, siliceous matter is the principal ingredient. Those fossils, 

 on the contrary, which, occurring in the same formations, are destitute of 

 organic texture, have their interior filled with substances of the same na- 

 ture as the strata in which they have been deposited. 



In a former work I concluded my general remarks on the plants which 

 I had then examined, in the following words : " Notwithstanding the 

 want of well defined concentric layers in those of the coal-formation and 

 mountain-limestone group, no doubt remains with me of their being Coni- 

 ferae. Should it be shewn, by future investigations, that recent plants of 

 other classes present a similarity of structure, the case will become different ; 

 but until then, it will remain established that these fossil plants come 

 nearer to the structure of the Coniferae than that of any other tribe. As 

 to the fossils of the lias, I presume no doubt can henceforth remain in the 

 mind of any one who may compare them with recent Coniferae, or be satis- 

 fied with the accuracy of my representations." After a more extended ex- 

 amination, I may repeat these words. The genera Peuce, Pitus, and Pi- 

 nites, are evidently of the same natural family, and although we have not 

 now trees resembling the two latter, they must necessarily be associated 

 with the first, which all must allow to be a genus of Coniferae. " 



I now proceed to the generic and specific characters of the plants ex- 

 amined. 



