26 GEOLOGICAL MEMOIRS. 



von Ettingshausen has proved in his Memoir upon the Basin of 

 Radnitz*, different floras — a circumstance which enables one to con- 

 clude either that they were formed in succession or that the coal- 

 beds were produced under varying conditions (as high-level or as 

 low-level bog-formations), and that the greater or less humidity has 

 exercised an influence upon the flora. 



The basins and troughs lie upon very various kinds of rock : the 

 basin of Harr is in gneiss, that of Merklin lies upon granite and 

 crystalline schist, and that of Pilsen rests upon the same descriptions 

 of rock in the south-west portion, and upon Silurian rocks in the 

 north-east ; upon the last-named formation repose also the other 

 basins. The author believes that from the absence of all contem- 

 poraneous marine formations, and even from the facts already 

 mentioned, it may be concluded that the Bohemian coal-deposits 

 have been formed in bogs and lakes in the midst of a somewhat 

 extended continent (or an island), which met the sea in the region 

 of the county of Glatz (Silesia), where the Carboniferous Limestone 

 now occurs, containing Productus latissimus, &c. This long series of 

 bogs was perhaps in connexion with those of Trautenau, Walden- 

 burg, and other places in the district of Glatz ; but the Upper Silesian 

 and the Moravian basins lay upon the other side of the sea-gulf. The 

 variation in the flora of the individual basins may perhaps be ex- 

 plained by the difference in situation : the Sigillaria- and Stigmaria- 

 bogs were perhaps on a high level, while those rich in Perns but poor 

 in coal were on a low level, and those which contain Stigmaria in 

 the lower beds and many Perns and Catamites in the upper were 

 probably high-level bogs which became changed to low-level bogs 

 through oscillations of level. 



Herr Ludwig then describes the basins and troughs in the follow- 

 ing order : — 



1. Basin of Pilsen. 



a. Trough of Wilkischen. 



b. Trough of Niirschan, 



2. Basin of Radnitz. 



3. Basin of Horschowitz. 



4. Basin of Miroschau. 



5. Basin of Merklin. 



6. Basin of Wranowa, near Mies. 



7. Basin of Steindorfel, near Manetin. 



8. Basin of Rakonitz. 



a. Coal-beds in the lower portion 

 of the Carboniferous formation. 



b. Coal-beds in the upper portion 

 of the Carboniferous formation. 



c. Coal-beds in the Rothliegende. 



9. Basin of Klein-Prschilep. 



10. Basin of Stradonitz. 



11. Basin of Buschtiehrad. 



In the beds below the coal-seams in the Wilkischen and Nurschan 

 districts (Basin of Pilsen) occur the Stigmaria jicoides, and thick, 

 long roots, which perhaps belong to Calamites, both very abundant. 

 In the beds above the coal-seams occur : — 



Sigillaria elegans, Brongn. 



ornata, Brongn. 



■ alveolaris, Brongn. 



Lepidodendron dichotomum, Sternb. 



Lepidodendron rimosum, Sternb. 



undulatum, Sternb. 



Calamites equisetiformis, Sternb. 

 communis, Ettingsh. 



No Perns have yet been found in these districts. 



To the north of Pilsen the flora consists of Sigillarice,Lepidodendra, 

 and Calamites, and some species of Neuropteris are said to be abun- 

 dant here. Prom the trough of Plass (Babina), Heir von Ettings- 



* Abhandl. der k. k. geol. Reichsanstalt. vol. ii. 1855. 



