GOPPERT ON THE COAL OF SILESIA. 21 



the plants are deposited in groups, assuredly a kind of gregarious 

 occurrence, with the predominance of one or the deficiency of other 

 species, or the wholly isolated appearance of some species. Stig- 

 mariajicoides, Calamites c?ecor«^w<s, and certain Sigillarias are almost 

 never wanting in Upper Silesia, and to these we must add in the coal 

 sandstones everywhere, also Artisia transversa, Sagenaria rimosa, S. 

 aculeata, and S. rugosa. In Lower Silesia Stigmaria ficoides is 

 indeed still more commonly accompanied hy Calamites cisti, Calamites 

 cannceformis, some Asterophyllites, above all by ferns, like Neuro- 

 pteris gigantea, Sphenopteris latifolia, Sphenopteris acutifolia, Ly- 

 copodites phlegmarioides, Sagenaria aculeata, Sagenaria rugosa, 

 Sagenaria rimosa. In the carboniferous sandstones we most com- 

 monly meet with Calamites cannceformis ; Artisia is here the greatest 

 rarity. The limestone beds in Lower Silesia, belonging to the coal- 

 formation, also possess their peculiar flora. Upper Silesia does not 

 contain such beds. 



8. The different coal-seams, together with the beds above and 

 below them (their roof and floor), must therefore be considered as 

 formed at distinct times, though all belonging to the same formation. 

 This the vegetation contained in them, which differs only in the 

 species and not in the genera, decidedly proves. 



9. In Upper Silesia I have as yet only found petrified wood, in a 

 single locality, and that not in the coal itself, but in the sandstone of 

 the roof in the formation at Janow near Myslowitz. On the other 

 hand, upright Sigillarise and Lepidodendrese (Sagenarise) filled with 

 a substance different from that of the including rock, are not rare 

 above the coal-seams. 



In Lower Silesia petrified stems are more abundant in the sand- 

 stone, in several points, as well in the Waldburg as in the Neurod 

 districts, and upright trees, mostly Sagenarise, more rarely Sigillarise, 

 are, if possible, more common than in Upper Silesia. 



10. Although the, with few exceptions, horizontal, or slightly in- 

 clined position of the Upper Silesian coal-seams, points to a very 

 quiet, slightly disturbed deposition of the vegetation forming them, 

 either in the place of its growth or not far from its native hills and 

 valleys, and we may be partly inclined to deduce from this its state 

 of preservation, more perfect than has yet been noticed in any other 

 place, still even here diverse conditions must have prevailed during 

 the deposition of the separate beds, affecting the preservation of the 

 plants, since in several places these are no longer observable in the 

 coal itself, as in the Zabrzer district, in the most easterly point of the 

 principal coal-deposit, and the most southern point near Hultschin. 



Singularly enough the coal in both these localities is distinguished 

 by its peculiar character when used for technical purposes, as it fur- 

 nishes the best caking coal. In the Lower Silesian coal, where on 

 the contrary, except Stigmaria, few plants are distinctly preserved, 

 caking coal is much less common. Hence we may perhaps conclude 

 that coal with well-preserved structure is to be regarded as only im- 

 perfectly mineralized. In Lower Silesia the formation of the coal 

 has in general taken place under less quiet conditions, or more cor- 



