STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. ]43 



Pyropissite occurs only where the cover is less than i6 meters; 

 (2) it is sometimes the upper bench, but, where the bed is very thin, 

 it is the only bench ; it is not always limited to the upper bench but it 

 may be distributed in the underlying Feuerkohle ; it occurs as leaves 

 in the main Feuerkohle, sometimes with distinct demarcation from 

 the surrounding coal but at others passing gradually into it; (3) it is 

 always accompanied by Russkohle, gypsum, and pyrite; retinite ap- 

 pears to be absent; (4) the character of the roof may be important; 

 under gravel and sand it is better than under clayey conglomerate; 

 but under a clay roof he has seen it both good and bad. 



Von GiimbeP"^ studied the pyropissite of Weissenfels. It is 

 powdery, dust-like, brown-yellow and difficult to moisten. Under 

 the microscope, it shows only indefinite grains, opaque lumps and 

 scattered leaves, ill-preserved and belonging apparently to some moss. 

 After removing the resinous substances by alcohol and ether and 

 treating the residue with Schultze's reagent, he found little evidence 

 of organic texture, aside from something like Faserkohle; there are 

 some spiral threads, and spores and pollen are indicated by rounded 

 patches. The ash, 14.2 per cent., consists of quartz grains, crystals 

 and opaque black balls. No diatoms were seen. Pyropissite from 

 Sauforst in southern Bavaria and of Miocene age, is in general much 

 the same; but remains of grasses and of moss leaves are numerous, 

 while pieces of wood are present, retaining structure though con- 

 verted into a yellow friable material like the groundmass. After 

 treatment with ether, the parts of leaves as well as the pollen grains 

 become more distinct ; pollen exines are very abundant. 



Fiebelkorn, in the memoir already cited, gives sections showing 

 the relations of Schwelkohle to ordinary coal. The bed at Grube 

 396 near Teuchern is only 6 to 7 meters thick, but at a little distance 

 away it is 16, and, generally speaking, the whole bed is good. Some 

 grains of coal are shown in the roof and the coal itself, especially 

 in the upper part, shows alternating bright and dull laminae. The 

 section at this place is : Black earth, 0.60 ; loess, 7.50 ; Tertiary shale 

 and sandstone, 6 to 8 ; impure coal, 0.30 ; Feuerkohle, 2.30 ; Schwel- 

 kohle, 0.50; Feuerkohle, 0.30 Schwelkohle, 4; Feuerkohle, 3; clay 



-*^^ C. W. V. Giimbel, " Beitrage," etc., pp. 146-148. 



