STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 435 



Barren interval, " Hexenstein Arkose," alternations of arkose, con- 

 glomerates, sandstones, and clay shale, with stems of Arauca- 

 rites schrollianus (beds of the petrified forest) ; 

 Schwadowitz beds with 3 to 5 seams, 2 of them workable locally. 



The prevailing color of the Ottweiler is red, but in the clay shales 

 it is gray. 



Goeppert^^ described the remarkable accumulation of petrified 

 stems in the Hexenstein arkose. This is exposed on a high sandy 

 ridge, extending northwestwardly from Radowenz to beyond 

 Schatzlar. The fragments, weathered out from the soft sand- 

 stone, are extremely abundant in an area of not far from 20 English 

 square miles. All of the stems seem to be prostrate and lie in 

 practical conformity to the bedding of the sandstone ; but they show 

 no evidence of transportation such as should be expected if they had 

 been washed out from their place of growth. The conditions led 

 him to believe that the fragments are the remains of an overthrown 

 forest. Those lying exposed on the surface have diameter of i to 

 4 feet, with a round or oval section and they are not waterworn ; the 

 length is from i to 6 feet, though in some cases it is 14 to 16 feet. 

 The stems belong to Araucarites schrollianus and A. brandlingii. 

 Petrified stems are numerous near Schatzlar as well as at some other 

 localities, but the great accumulation is at Radowenz. 



In his earlier work on the eastern side of the field, Goeppert 

 divided the area into two districts, Waldenburg at the north and 

 Neurode at the south ; but these are continuous. The dips are high, 

 usually between 45° and 70° and the whole region was disturbed 

 greatly by porphyry outbursts. Conglomerate, almost wholly want- 

 ing in the Upper Silesian Field, and coarse sandstone prevail ; but 

 these coarse rocks are not in contact with coal seams. The number 

 of seams is greater than in the other Silesian field, but " rest pe- 

 riods," during which shales and coal accumulated, were brief and 

 irregular ; so that, while the maximum thickness of coal is great, the. 

 available quantity is comparatively small. In Upper Silesia, the 

 coal seams consist chiefly of tree-like Lepidodendron, some Sigil- 



22 H. R. Goeppert, " Ueber den Versteinden Wald von Radowenz bei 

 Adersbach in Bohmen, etc.," Jahrb. k. k. Geol. Reichsan., Band VIII., 1857, 

 PP- 725-738. 



