Vegetables in Coal Measures. 21 1 



cur, placed yertically, traversing all the strata, and of 

 which the view joined to this notice only shews a small 

 number. It is a true fossil forest, of monocotyledonous ve- 

 getables, resembling bamboo, or a large equisetum as it 

 were petrified in place. 



Although the beds of the coal measures are here evidently 

 horizontal, it is remarked that there has been, after the 

 precipitation and even consolidation of the upper sandstone, 

 a sliding movement, of little extent certainly, but sufficient 

 in many points to break the continuity of these stems; so 

 that the upper parts are as it were thrown on one side, and 

 are not continuous with the lower. 



It does not enter into my plan to describe these vege- 

 tables, nor to search to determine to what family they may 

 belong : it is a very important and difficult subject, and 

 cannot be treated en passant. My son, aided by the coun- 

 sels of M. Decandolle, and the help of geologists, has long 

 since undertaken a special work on this portion of botany, 

 the object of which is, the study of fossil vegetables; for 

 by too superficially and rapidly naming the vegetables of the 

 coal measures, one risks propagating opinions on their ge- 

 nera, which might be erroneous. But although I ought to 

 speak here only of the position of these stems, and not of 

 their nature, I cannot avoid offering, under this point of 

 view, some observations relating directly to those of St. 

 Etienne. 



There are at the Treuil mine two very distinct kinds of 

 stems : those of one class are cylindrical, articulated and 

 striated parallel to their edges ; they do not in their interior 

 present any organic texture, WieXr probably reedy (fistulaire) 

 cavity is entirely filled with a rock of the same nature as 

 ihat composing the beds they traverse. These stems are 

 the most numerous, they vary much in diameter from 2 or 

 3 centimetres only [about 1 inch] to 1 or 2 decimetres |[4 to 8 

 in.], and perhaps beyond. Their greatest length appeared to 

 us to be 3 or 4 metres [9 f. 10 in. to 3 f. 1 in.]. Their sur- 

 face is often covered by a ferruginous and even coaly de- 

 posit or coat. 



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