138 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



rare. There is little difference in the wood and the fragments appear 

 in all cases to belong to the genus Pinus. Ordinarily they are com- 

 pressed and the annual rings are ellipsoidal. A yellowish-white resin, 

 without succinic acid, is present in all types of the coal. 



Buchow, west from Fiirstenwalde, is at a few miles east from 

 Berlin. There the coal is laminated with, as Plettner remarks, 

 enough bitumenose Holz to keep one from forgetting the vegetable 

 origin of the coal, as he might do if he consider only the homo- 

 geneous substance in which the wood is embedded. At Freinwalde, 

 15 or 20 miles north-northeast from Berlin, the dip is only 10 

 degrees, whereas at Buchow it is 15 to 60. The coal at Freinwalde 

 contains no wood and burns with a very disagreeable peat-like odor ; 

 this type, observed also at Buchow, is the ]\Ioorkohle of Plettner. 

 Plant remains, recognizable by the unaided eye, are few, and such 

 as were seen were pierced by threads of resin ; but, in the neighbor- 

 ing area of Falkenburg, wood abounds. 



This Moorkohle is shown near Frankfurt a. O. and at some other 

 places. The dips in the basins of this eastern region vary from 

 10 to 60 and in one basin even to 90 degrees. At most localities the 

 coal is laminated and contains resin as well as wood ; the latter is 

 often converted into Pechkohle and in that conversion it loses struc- 

 ture. Plettner calls attention t othe fact that the change into Pech- 

 kohle rarely affects the w'hole fragment. The converted portion is 

 not altered by exposure to the air and does not separate into lamellse. 



The coals of Sachsen or Prussian Saxony have been studied by 



many observers. Laspeyres^^'* examined an area near Trotha and 



Dolau, where the coal was mined by stripping. The lower bed is 



2 to 6 meters thick and divided by an irregular parting of sandy 



clay. The upper bench is often so poor as to be worthless ; the lower 



bench is better but consists chiefly of Formkohle with some Knor- 



pelkohle. It contains much coarse or earthy retinite in nests, streaks 



or layers, as well as much pyrite, petrified wood and charcoal. At 



a little distance higher is the upper bed, with extreme thickness of 5 



meters. This consists of Formkohle, small particles of brown-black 



coal, more or less closely packed together. Occasionally it is dust- 



19* H. Laspeyres, " Geognostische Mittheilungen aus der Provinz Sach- 

 sen," Zcitsch. d. d. geol. Gesell, Bd. XXXIV., 1872, pp. 298-302. 



