214 M. Beongniart on the fossil 



metres* [13 f. 1 in.]. The presence of branches, which 

 does not appear doubtful, establishes a remarkable difference 

 between this fact, that of St. Etienne, and those we have 

 tiuoted. 



Lastly, M. Habel has observed in these same mines vege- 

 table stems placed almost vertically, which do not differ 

 from ours ; they were from 2 to 2| metres [about 6 f . 7 in. 

 to 8 f.] in height, and about 25 centimetres [10 feet] in dia- 

 meter ; they were articulated, regularly grooved, and covered 

 by ^ little coal. These stems traversed beds of the forma- 

 tion which contain carbonate of iron ore. 



A trunk of a tree in a vertical position has lately been 

 observed in the sandstones which cover the coal formatiort 

 of Glasgow, on the N.W. of that town : this trunk was about 

 6 decimetres [2 feet] in diameter, its transverse section pre- 

 sented a nearly oval figure ; it was, like those I have des* 

 cribed, entirely filled with the rock composing the matrix 

 in which it occurred ; but the bark, that is to say, the exte- 

 rior part of this vegetable, for nothing shews that it had a 

 real bark, was converted into coal. It was cleared for the ex* 

 tent of about a metre [about 3 f, 3^ in.] and no branches were 

 observed ; yet at its lower part, roots were said to have been 

 seen, especially four of large size, dipping under the ground 

 like those ordinary trees. It could not, says the author of 

 this notice, be referred to any known tree. (Thomson, An-* 

 nals of Philosophy, 1820, November, p. 138). 



I do not speak of the stems and trunks of true trees, not 

 only fossil, but changed into silex, which are observed in 

 the rocks of a formation absolutely different and always pos- 

 terior to that of the coal ; these petrified woods are very 

 numerous, but their geological position distinguishes them 

 essentially from those which form the subject of this notice. 



It is probable that the examples of stems traversing the beds 

 of the coal measures are also very frequent, and that if but 

 a small number have been noticed, and so few figures of 

 them have been published, it is owing to the manner in 



* Biblioth: univers: 1818, t. ix. p. 256. 



