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Updated: May 29, 2025
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.
The region marked c is carbonized; the organic elements of the wood-cells, tracheæ, etc., have undergone but little change in shape. Arthropitus gallica, St. This region, already filled by petrifying salts, but not completely hardened, has not been able to resist, as the region, a, an external pressure, and has become more or less misshapened.
The layer of coal in contact with the carbonized or silicified part of the specimens is due, then, to a compression of the organic elements already chemically carbonized, but in which the mineral matter was not yet hardened and was able to escape. Arthropitus gallica, St. If this be so, we ought to find the remains of organic structure in this region c.
This being the case, it was considered of interest to ascertain whether the carbonized portion had preserved a structure that was still recognizable, and, in such an event, to compare this structure with that of the portion of the specimen that was preserved in all its details by mineralization. Arthropitus gallica, St.
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