456 STEVENSON— INTERRELATIONS. OF FOSSIL FUELS. 



obtained at several horizons and the flora is rich in Rothliegende 

 forms, among them, Callipteris conferta. With these are many 

 Coal Measures species, but no Sigillaria or Stigmaria. 



The Upper Ottweiler, about 125 meters thick, has mostly grayish 

 deposits, laminated shales and micaceous sandstones. In Bavaria, 

 it has the Breitenbacher or Hausbrandflotz, 12 to 30 centimeters 

 thick, which is mined by stripping at many places, as the coal is an 

 excellent domestic fuel, being maigre, smokeless and without clinker. 

 The flora is mingled Saarbriick and Rothliegende; Weiss, quoted by 

 V. Amnion, has described it as a " prevailingly stone-coal flora ; 

 Stigmaria, Sigillaria and Loniatopliloios still abundant, ferns numer- 

 ous, Walchia rare." Animal remains are few, chiefly insects and 

 crustaceans. The Middle Ottweiler is a thick complex of mostly 

 red sandstone and conglomerate, with red, bluish and yellow shales. 

 The conglomerates, according to Nasse, are not constant but are 

 lenses. The Hirteler coal seams are unknown in Bavaria but are 

 present near Saarbriick in Prussia. Fossil plants are not abundant 

 and such as do occur are indefinite, but silicified wood is not rare, 

 v. Ammon states that the mass is 800 meters thick near Saarbriick, 

 but near Dudweiler in Bavaria it is 950. The Lower Ottweiler, 

 formerly regarded as Upper Saarbriick, about 800 meters in western 

 part of the basin, contains much red rock, gray, reddish and greenish 

 shades and sandstones. Its base is the Holzer conglomerate, which 

 is characteristic at the east but becomes insignificant toward the 

 west. Over it are the Leaia shales, which enclose thin layers of 

 limestone and underlie the Hangenden Flotzug, consisting of gray 

 and some red sandstone and shale with two or three variable seams 

 of coal. The thicker seams, Lummerschieder and Walschieder, are 

 of workable thickness in the Prussian area but become insignificant 

 or disappear toward the east in Bavaria. At Frankenholz, 5 coal 

 streaks were found "but at Dittweiler, farther east, no trace of coal 

 was found in the boring. The thickness in the Prussian area is not 

 far from 1,000 meters and is considerably more in Bavaria. 



The Saarbriick is divided into the Upper or Flammekohlen- 

 gruppe, yielding a sintering coal, and the Lower or Fettkohlen- 

 gruppe, from which coking coal is obtained. Conglomerates are 

 numerous, especially in the western portion, where, according to 



