74 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



interval, but the top bed is usually about 90 feet above the second. 

 Each bed is limited above and below by coaly shale, 2 inches to 

 2 feet thick, which passes gradually into gray-blue marly clay. The 

 lower beds are double, divided by carbonaceous shale. The parting 

 in the lower bed is 2 inches thick, at 2 to 3 feet from the floor and 

 is known as the " Hohl-lag " ; that in the middle bed, known as the 

 " Koth-lag," is almost paper-thin but is persistent. Besides these 

 there occur occasionally in these beds layers of charred material, 

 one third to one half inch thick and termed "Brand-lag"; they are 

 of limited extent and cannot be regarded as partings. As the 

 peculiarities of the beds convinced the author that these are com- 

 posed of in situ plants, he explains the "Brand-lag" as derived 

 from burned vegetable matter^ — that possibly the surface of the 

 deposit had been ignited by lightning. After the fire had burned 

 out, vegetation began anew. The mass of charred matter is enclosed 

 in unchanged lignite, the separation being sharply defined. 



Schreiber^^ has referred to two diluvial moors, one near Piehl in 

 Styria and the other at Hopfgarten in Tyrol. That at Piehl is at 

 200 meters above the bottom of the present valley and is from one 

 to one and a half meter thick. It underlies 150 meters of con- 

 glomeratic materials, and this great burden has so compressed it 

 that it resembles brown coal; but Schreiber objects strenuously to 

 the term Schieferkohle, preferring Schiefertorf, to distinguish it 

 more sharply from the Tertiary brown coal. At Piehl, it rests on a 

 marl ; the lowest layer is brown hypnetum peat with loose texture, 

 on which rests reed or rush peat, containing much earthy matter. 

 Then follows a comparatively thick layer of Bruchtorf, composed 

 chiefly of firs and birches. The highest layer is ,a sedge-moss peat 

 and is thin at all localities examined by Schreiber. Overlying this 

 bed is sandy clay, succeeded by moraine stuff and glacial debris. 

 The Hopfgarten deposit overlies more than 100 meters of glacial 

 debris, from which it is separated by clay bands. It was measured 

 at three places and the thickness seems to be almost constant at 

 about a meter and a half. The lowest portion is Riedtorf, with 

 much mud and consisting mostly of sedges, though, here and there, 



95 H. Schreiber, " Vergletscherung und Moorbildung," etc., pp. 27-29. 



