STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 455 



Lower deposits are unknown and it is uncertain whether or not 

 the Waldenberg (Sudetic, Lower Westphalian) and Lower Carbon- 

 iferous are present. The rocks are of Hmnic origin; no marine 

 forms have been observed. 



Dannenberg gives the thickness of Rothhegende as not less than 

 2,000 meters, that of Ottweiler as 1,500 to 2,000 and of Saarbriick 

 as 2,500 to 3,000 meters. Nasse estimated that Ottweiler is 1,700 

 to 2,000 in the area between Saar and Blies Rivers, but 3,000 in 

 the eastern portion within Bavaria ; the Saarbriick, on the contrary, 

 become thinner toward the east, being 3,200 on the Saar but only 

 2,100 on the Nahe River. Borings in later years have proved that, 

 while it is true that Ottweiler increases notably toward the east and 

 that Saarbriick decreases notably in that direction, the variations are 

 not so great as Nasse believed. It is very clear that influx of mate- 

 rial for Saarbriick was from the west and for Ottweiler from the 

 east, the coarse deposits for the latter being on the east side, while 

 in the former they are on the west side. 



The number of coal seams, according to Dannenberg, is not far 

 from 400, of which 150 to 160 are workable, that is to say, are more 

 than half a meter thick. Nasse showed that these are grouped into 

 " Flotzzuge," separated by practically barren intervals. The coal 

 seams of the Rothhegende and Ottweiler are not important and only 

 insignificant seams were formed above the Kuseler beds. There 

 were serious extrusions of igneous rocks in the earlier Saarbriick 

 and in the closing portion of the Upper Rothhegende. 



Thin coal is present in the Lebacher beds, which are mostly yel- 

 low sandstone and dark shales ; in the western portion, the shales 

 have fish remains and iron ore, but the ore is wanting at the east. 

 The flora, according to Nasse, consists almost wholly of Rothhe- 

 gende forms, with very few of Coal Measures type. The Upper 

 Kuseler rocks are mostly gray shales and sandstones ; coal seams 

 were observed at many places ; one, the Kalk-kohlen Flotz, has a 

 limestone roof and occasionally becomes 47 centimeters thick ; an- 

 other, near the base, the Muschel-kohlen Flotz, is from 15 to 20 

 centimeters thick and its shale roof has abundant Anthracosia. The 

 Lower Kuseler consists chiefly of gray and red sandstones, varie- 

 gated shale and thin layers of limestone. Fish remains have been 



