72 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



place only in small stems and is rare when the diameter exceeds 2 

 inches. One end of a stem may be changed while the other retains 

 its woody structure. 



Kle'bs^^ described a coal which he saw at about 30 miles south- 

 west from Konigsberg: it underlies 15 feet of sand and overlies 

 gravel, both of them diluvial. The section, descending, is : Black 

 earthy coal, i foot; clear brown coal, 7 inches; dark, brown coal, 

 3 inches. The three benches are as sharply distinct as those of any 

 peat bog or bed of stone coal. The whole thickness, including the 

 thin partings, is 2 feet and the middle bench is harder than that 

 above it. 



Von Glimbel,^^ who had studied the Bavarian Schieferkohle in 

 place, subjected to microscopical examination material collected at 

 localities in Bavaria and Switzerland. He describes the Schiefer- 

 kohle as partly loose, partly dense in structure, often like Pechkohle. 

 It contains many flattened branches and parts of trees belonging to 

 conifers, birch, willow, alder, in part lignite but at times already 

 Pechkohle. Solution of caustic potash converts the less dense por- 

 tion into a soft closely felted mass, in which the microscope shows, 

 as predominating, parts of mosses and grass leaves. Tissue of wood 

 appears rarely. The dense Pechkohle required treatment with 

 Bleichflussigkeit (potassium chlorate and nitric acid) in order to 

 bring out the structure. The densest material is that from Mor- 

 schwyl, which shows the same plants as those in the looser or less 

 dense portions along with an amorphous textureless substance like 

 dopplerite. The density is due to this material, which he terms 

 Carbohumin. Pollen, spores of mosses and lichens are not very 

 abundant ; cones of conifers are numerous in the coal mass, but are 

 little deformed though they lie alongside of compressed stems. The 

 inside of stems is yellowish and soft like decayed wood, but the 

 bark zone has been converted into bright Pechkohle. 



The Bavarian localities are typical. At Imbergtobal, near 

 Sonthofen, a brown coal deposit is divided by partings of sandy 

 marl, which are crowded with plant fragments and conifer needles 



91 R. Klebs, " Die Braunkohlenformation um Heiligenbeil," Schrift. Ges. 

 Konigsberg, Jahrg. 21, 1880, p. 82. 



^- C. W. V. Giimbel, " Beitrage," etc., pp. 135-138. 



