United States or Kuwait ? Vote for the TOP Country of the Week !
When reduced to thin, transparent plates, these latter show us the organization of the wood of Arthropitus, Cordaites, and Calamodendron, and of the petioles of Aulacopteris, that is to say, of the ligneous and arborescent plants that we most usually meet with in the coal measures of Commentry in the state of impression or of coal.
Neither can we admit that the penetration of the plants by bitumen was effected at a certain distance, and that they have been transported, after the operation, to the places where we now find them, since it is not rare to find at Commentry trunks of Calamodendrons, Anthropitus, and ferns which are still provided with roots from 15 to 30 feet in length, and the carbonized wood of which surrounds a pith that has been replaced by a stony mould.
The corky nature of this region of the bark was likely richer in carbonizable elements than the wood properly so called, and had, in consequence, to undergo much less shrinkage. Dr. Commentry cannel coal, X200. Etienne; transverse section, X200. Calamodendron, Commentry; prosenchymatous portion of the wood carbonized, X200.
A thin section of a piece of Commentry cannel coal shows that this substance consists of a yellowish-brown amorphous mass holding here and there in suspension very different plant organs, such as fragments of Cordaites, leaves, ferns, microspores, macrospores, pollen grains, rootlets, etc., exactly as would have done a gelatinous mass that upon coagulating in a liquid had carried along with it all the solid bodies that had accidentally fallen into it and that were in suspension.
One will remark here again a slight increase in the proportion of carbon, as was to be foreseen. The elementary composition found nearly corresponds with that of the coal taken from the large Commentry deposit. Although the chemical composition is nearly the same, the manner in which the different species or fragments of vegetables behave under distillation is quite different.
The coal measures of Commentry, as well as certain others, such as those of Bezenet, Swansea, etc., contain quite a large quantity of coal gravel in sandstone or argillaceous rocks.
Fayol, we have been enabled to make such researches upon numerous specimens that were still inclosed in their sandstone gangue and that had been collected in the coal strata of Commentry. In some of their physical properties they differ from the more recent isolated fragments and from the ordinary coal of this deposit.
Word Of The Day