GOPPERT ON THE COAL OF SILESIA. 19 



separate superimposed beds, whether of coal or of slate-clay and sand- 

 stone, teach us that, although they belong to one formation, as is 

 shown by the generic agreement of the plants contained in them, 

 they have yet been produced at different times, and deposited in long 

 periods during which the conditions above noticed as acting in the 

 formation of the strata were repeated. Though far from wishing to 

 make even an attempt to determine the length of time in which 

 these beds were formed, yet referring to many observations quoted in 

 my work on the quick renewal of the flora in tropical regions, and 

 also on its remarkably rapid decomposition, I would remark that a 

 shorter period is required for this purpose than it has been usually 

 thought necessary to assume. 



In respect to the diversity of the coal-beds in Upper and Lower 

 Silesia, Professor Goppert makes the following observations: — 



1 . The predominant vegetable origin of the coal in Upper as well 

 as Lower Silesia cannot be doubted. In the former marine produc- 

 tions are entirely wanting, and hence the sea probably had no part in 

 their formation. In the Lower Silesian deposits marine fossils occur 

 along with land-plants only in some single limestone beds in the red 

 sandstone above the coal. 



2. The large thick stems of Sigillaria, which are found well pre- 

 served in the coal itself in almost every locality, contributed the most 

 to the formation of the coal in Upper Silesia. Hence the coal of 

 many extensive tracts, as for instance of the Nicolai district, of the 

 pits on the Przemsa in Silesia, in the kingdom of Poland, and in the 

 free state of Cracow, may in general be well designated as Sigillaria- 

 coal (si a potiorijit denominatio) ; and to this circumstance we may 

 perhaps also ascribe the immense thickness of the coal in this basin, 

 sometimes reaching to seven fathoms. 



None of the other large families of carboniferous plants, with the 

 exception of the Araucarise, occur here in such abundance in the coal. 

 The Lepidodendrese (Sagenaria) and Stigmarise only preponderate in 

 individual beds, as in the Friedrich's pit near Zawada, and with them 

 the Calamites. The Calamites and Noggerathia are found only spa- 

 ringly ; the Ferns are everywhere wanting in the coal, or at least have 

 not yet been found by me after the most diligent search for them ; 

 and we may perhaps assume that they were originally wanting .at least 

 in those points where the Lepidodendrese with its so delicate bark is 

 found well preserved, as in the Friedrich's pits mentioned above. In 

 Lower Silesia the beds nowhere attain the thickness of those in the 

 upper province. Although Lepidodendrese are abundant in the slate- 

 clays, and Sigillariae also occur, though fewer, and the fibrous variety 

 is never wanting in the coal, yet the former are only observed much 

 dispersed and isolated in the coal itself, whilst Stigmaria ficoides ap- 

 pears in incredible abundance, and probably, with a great multitude 

 of herbaceous plants like ferns, whose structure has almost entirely 

 perished, formed the coal-beds, which, however, must be of inferior 

 thickness, since these plants could not furnish such a mass of vege- 



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