430 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



mine works two seams, 24 and 60 inches thick, separated by an in- 

 terval of 48 to 54 feet. The lower yields a laminated, hard, cok- 

 ing coal but coal from the upper one was considered to be inferior. 

 When the lower seam was almost exhausted, work was begun on 

 the upper. Its coal resembles Blatterkohle, consisting of hard, 

 glance-like lamellae alternating with thinner dull laminae, composed 

 of compressed barks of Lepidodendron, Calamites, Stigmaria and 

 Sigillaria, all distinct. Goeppert states that, in many ways, this re- 

 sembles peat. At a mine in this Nikolai district, the coal contains 

 great abundance of Sigillaria and Lepidophloios and an "incredi- 

 ble " mass of Sigillaria is in the roof. There he obtained Sigillaria 

 and Alethopteris with leaves only slightly brown and completely 

 flexible, preserving the minutest details of structure. Union of coal 

 seams is a familiar feature in the Nikolai district. Additional ob- 

 servations by this author will find place in another connection. 



Goeppert makes only passing reference to the Austrian part of 

 the field; but material information respecting one portion has been 

 given by Petrascheck^^ in a paper dealing especially with the Peters- 

 wald trough, lying between the Ostrau trough at the west and the 

 Karwin trough at the east. With Stur and Gaebler, he recognizes 

 Ostrau beds in the western part of the trough but he finds the Sat- 

 telfiotz beds in the eastern portion, where the disturbance was so 

 severe as to cause inversion. A serious difficulty encountered in 

 correlation was found in the sudden changes in character as well 

 as thickness of the deposits, which mark some horizons more than 

 others. It appeared to him that the Ostrau beds were deposited on 

 a rudely level oscillating coast, so that paralic and limnic conditions 

 alternate. In discussing the evidence of overturned stratification, he 

 presents some facts which have interest here. 



The layer of " Schramm," soft, more or less clean coal, passing 

 at times into shale, is, as a rule, on the floor of the coal seams ; occa- 

 sionally, it is found in the body but very rarely on top of the coal. 

 In the Sophien coal mine, all coal seams have the " Schramm " on 

 top, the Faux-mur having become the Faux-toit. Reed-beds or 

 underclays with Stigmaria appendages crossing the bedding, are the 



28 W. Petrascheck, " Das Alter der Floze in der Peterswalder Mulde, 

 etc.," Jahrb. k. k. geol. Reichsanst., Band 60, 1910, pp. 779-814. 



