STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 429 



than a pea ; the prevaihng rock is sandstone, gray to yellow, which 

 in some localities weathers to a carved or fretted surface. It is 

 quartzose and has little cementing material. Clay shales are inter- 

 calated in the sandstone mass and they are associated with the coal 

 seams. Near the coal, these 'shales often are rich in bitumen, be- 

 coming Brandschiefer and frequently containing much pyrite. Ir- 

 regularity of deposit is evident from the rapid change of sandstone 

 into clay shale. Sphaerosiderite occurs chiefly where the coal 

 seams are thin and alternating with shaly clays. 



This region is marked by the thickness, extent and regularity of 

 the coal seams, according to Goeppert; but when he studied the 

 area, the correlation was very uncertain. The thickness is from 3 

 to 12 feet, but at one locality it reaches 42 feet. About 20 seams 

 are workable. Dips commonly are less than 12°, but near the Car- 

 pathians they are higher. The thicker seams are ordinarily in sev- 

 eral benches, varying not only in thickness but also in character of 

 the coal ; some benches are caking, others, not. Laminated coal is 

 the predominant type and occurs, as a rule, in the top and bottom 

 portions ; Grobkohle forms the best benches of thick seams and for 

 the most part is confined to the middle, being found rarely in other 

 parts; clean Pechkohle is less abundant and Blatterkohle seldom 

 occurs. In great districts, every coal seam contains remains of 

 plants, especially of Sigillaria; Faserkohle is in all seams and some- 

 times it predominates, making the coal loose. 



At Zabrze, the seams [Sattelflotz] contain much Faserkohle; 

 that material predominates in the highest, which is 13 feet thick. A 

 sandstone quarry in the Brenz district, on the Poland border, has 

 great stems of silicified wood — an unusual occurrence in the Upper 

 Silesian field. Near Myslowitz he saw Sagenaria stems standing 

 on the coal, one of them 4 feet high and 2 feet in diameter. In the 

 Locomotive mine, there, erect Sigillaricc are abundant in the roof 

 of the coal seams. On the Poland border, the lowest seam near 

 Dabrowa is 78 feet thick, divided midway by 6 feet of Brandschiefer, 

 consisting of compressed Sigillaria associated with a little clay. The 

 same Sigillaria is in the coal along with Faserkohle. Goeppert 

 states that the Sigillaria is incredibly abundant. 



At Zawada in the Nikolai district [Saarbriick], the Friedrich 



