442 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



irregular. At both extremities of the basin it is too thin to be 

 worked, but in two sub-districts, near Kladno at the north and 

 Rakonitz at the southwest, it becomes workable ; but even in these 

 the variability is serious ; a strip without available coal divides the 

 Kladno district. In that district, the Hauptflotz at times rests di- 

 rectly on the older rocks, the Grundflotz being absent. It is in three 

 benches with 3.75 to 5 meters of partings. In the eastern part of 

 the district, the middle and lower benches are practically worthless, 

 the ash being 26 to 28 per cent. ; in the western portion the seam, 12 

 to 18 meters above the thick but worthless Grundflotz, is still triple, 

 but the partings have become thin, so the whole mass, 9 to 12 meters 

 thick, is mined as a single bed. In the Rakonitz area, the Hauptflotz 

 occasionally has 4 to 5 meters of coal, but, especially toward the 

 west, it tends to break up, so that there are few localities where it 

 can be mined. Coal in the northern part of this basin is maigre 

 and dirty, but near Kladno, it becomes fatter and at times less dirty : 

 ash varies from i to 30 per cent. ; caking coal is rare and cannel 

 occurs at some localities. 



Near Lubna, beyond Rakonitz, is the Lubna seam, of which 

 Katzer^^ has given the section, which, descending, is: (i) Compact 

 coal, in part brown, 0.30 to i.io; (2) black clay parting, 0.03 to 0.20; 

 (3) black cubical coal, 0.20 to 0.30; (4) compact brownish cannel 

 with Stigmaria, 0.20 to 0.25; (5) thinly laminated Brandschiefer, 

 with remains of ferns, o.io to 0.20; (6) clay with sphaerosiderite, 

 0.20 to 0.50; (7) hard Brandschiefer, with remains of plants, O.io 

 to 0.20. 



The accepted reference of this seam, at the time when Katzer's 

 work was published, was to the Permian, but later studies have 

 proved that its place is in the basal portion of the Saarbriick and 

 that the associated flora is Carboniferous, not Rothliegende. The 

 presence of abundant Stigmaria in the cannel is worth noting. The 

 same form abounds in a clay parting near Rakonitz. 



The higher coal group, in upper part of the Schlaner beds, is 

 separated from the lower group by the great mass of the Kladno- 

 Pilsen sandstones, the Teinitzler beds and the lower portion of the 



3'^ F. Katzer, "Geologic von Bohmen," 2te Aufl., Prag, 1902, pp. 11 18, 

 IT =8. 



