IN THE STRATA OF THE CARBONIFEROUS SERIES. 47 



Fig. 6. The portion of the same fossil here represented, is that border- 

 ing upon an irregular vein of carbonaceous or earthy matter. The dark 

 transverse lines in this figure, like that in the last, are not truly the lines of 

 separation of concentric layers, although some of them may occupy the space 

 formed by the disruption of two of these layers. 



This fossil seems to be of the same species as the Wideopen tree, which 

 is also the case with another found at Westgate near Newcastle, and a 

 specimen sent to me by Mr Phillips of York, which was found in the 

 West Riding coal-field, together with several others from the north-eastern 

 parts of England. 



The tissue of a Pinites is readily distinguishable in a fossil plant, but 

 although there may be many species of the genus, I am not aware of any 

 infallible characters by which we can point them out, seeing we are confined 

 to the organic tissue alone. Many recent pines are so similar in texture, 

 that although a person who has dissected and compared their tissues, 

 might be able to distinguish many of them at sight, it would yet be quite 

 impossible to characterize them in words ; and there seems no great hope 

 of our being able to distinguish the fossil species of a genus by tissue alone, 

 since it is so liable to be altered in its appearance, that even from the same 

 trunk specimens might be obtained, differing so much from each other as to 

 induce a person not aware of their common origin to consider them as dis- 

 tinct. 



In concluding my observations on the fossils retaining organic structure, 

 which I have found in the carboniferous series, I consider it of importance 

 to advert to a difference in chemical composition exhibited between those of 

 the mountain limestone series, and those of the coal formation properly so 

 called. 



As illustrative of this subject, I may present the following remarks, 

 which were kindly transmitted to me by Mr James Johnston, Porto- 

 bello, upon the Wideopen Fossil, and that of High Heworth. 



" The fragments of the two fossils have the same external characters. 

 Both are of a dark brown, from the presence of pe/oxide of iron, in a very 



