GOPPERT ON THE TRANSITION FLORA OF SILESIA. 35 



On the Fossil Flora of the Grauwacke or Transition Rocks o/'Silesia. 

 By Professor Goppert of Breslatj. 



[Karsten u. v. Dechen's Archiv fiir Miner, xxiii. pp. 60-72, 1849.] 



In carrying out the commission given him early in the year 1844 by 

 the chief surveyor of mines. Count von Beust, to explore Upper Silesia, 

 Dr. Goppert made the grauwacke formation of South Silesia and its 

 hitherto unknown fossil flora his chief object of inquiry, and that, more 

 particularly as, from his acquaintance with these strata and their ve- 

 getable organic remains, he had long cherished the opinion that the 

 grauwacke possessed a peculiar flora. 



On the Transition Rocks of Silesia. 



Of the now subdivided formation, formerly known as transition or 

 grauwacke, we have in Silesia, says Dr. Goppert, in the upper Kun- 

 zendorfer strata, perhaps only the newest part of the series, the so- 

 called Devonian, whilst the rest might be regarded as the lowest 

 member of the coal formation, the deposition of which preceded the 

 formation of the coal-measures. 



In the whole Leobschiitz district, the grauwacke, which is to be re- 

 garded only as an outlier of the great mass of the formation in the 

 Austrian Principalities Jagerndorf and Troppau, forms more or less 

 elevated hills capped with clay. On the declivity of the district 

 towards the valley of the Oppa, the summits of these hills, composed 

 of grauwacke slate, are not covered with clay. Natural sections of 

 these rocks appear only in the river-courses, as for example on the 

 Mora, near Castle Fiillstein, Fort Meidelburg and other places. 

 Generally the nature of the rock is evident only at the quarries, and 

 these occur more or less plentifully near every village. [The order 

 in which Dr. Goppert visited the quarries in the Leobschiitz district 

 and in the neighbouring Austrian Silesia then follows.] 



The composition of the grauwacke in this upland-district is very 

 uniform. Two chief varieties are conspicuous, accordingly as the 

 grauwacke is disposed in thick beds or as grauwacke- or clay-slates. 

 The first is generally grey, of greater or less hardness according to the 

 size of the quartz crystals and white mica-flakes, its chief consti- 

 tuents ; rarely almost bluish, sometimes reddish from the intermingled 

 feldspar crystals, as near Kreuzendorf. 



The beds are of variable thickness, from one or two inches to one 

 and sometimes even ten feet, as in the quarry on the Mora between 

 Gratz and Troppau, which exposes a fine section of from sixty to 

 eighty feet perpendicular height. Very often the strata are horizontal, 

 as in the quarries near Leobschiitz, with an inclination towards the 

 east. Towards its termination a stratum usually diminishes in thick- 

 ness, and the rock, from the preponderance of argillaceous matter, 

 gradually passes into a soft bituminous clay-slate, and the mica-flakes 

 disappear ; or the separation of the constituents is more sudden and 

 distinct. 



In the thick beds, for instance iu the quarries near Troppau, sepa- 



d2 



