122 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



cept in western Canada. Eocene coals are present in Bavaria, 

 Austria and Hungary, but, for the most part, the areas are incon- 

 siderable. Deposits of this age in India, Java, Sumatra and Borneo 

 are well known, while those of western North America are the 

 main source of supply for a vast area. 



Classification of Tertiary Coals. — As the Tertiary brown coals 

 have supplied a great part of the fuel consumed in Germany and 

 much of France during more than two centuries, they have been 

 classified to the last degree of detail. Brongniart^''^ recognized four 

 types. Lignite jayet, which he thought equivalent to Pechkohle, 

 though it is evident that his reference is to the mineral jet; Lignite 

 friable, la houille limoneuse of Brochant, regarded by him as syn- 

 onymous with the German Moorkohle ; Lignite fibreux, which retains 

 the woody structure ; Lignite terreux, bituminose Holzerde, com- 

 monly known as Terre de Cologne, black to blackish brown, with fine- 

 grained earthy fracture, mostly homogeneous, but containing em- 

 bedded trunks of trees. 



Zirkel's^*'^ grouping utilized the popular names as employed in 

 Germany : Pechkohle, compact, brittle, pitch-black, waxy or greasy 

 luster, conchoidal fracture ; approaches stone coal but is structure- 

 less; Gemeine Braunkohle, or common brown coal, compact with 

 more or less conchoidal fracture, less hard and brittle than Pech- 

 kohle, blackish brown to pitch black, with or without woody struc- 

 ture, passes on one side into Pechkohle and on the other into Moor- 

 kohle, a dense mass even in structure, black with bright streaks, is 

 closely related to Erdkohle, or earthy brown coal, which is a friable 

 mass of dust-like more or less loosely consolidated fragments, with 

 dull luster and earthy fracture ; Lignit or wood brown coal, in 

 masses showing texture of wood, twigs, flowers, roots, etc. ; Bast- 

 kohle and Nadelkohle are merely varieties of Lignit; Blatterkohle, 

 Dysodil and Papierkohle are finely laminated ; Wachskohle contains 

 62 per cent, of paraffin. 



Zincken^*^^ presented a somewhat similar classification but in such 

 detail as to exhibit sufficiently the great complexity of the group 



161 Al. Brougniart, " Mineralogie," T. 2, pp. 50 fif. 



162 F. Zirkel, " Lehrbuch der Petrographie," Bd. I., pp. 390-392. 



163 C. Zincken, "Die Physiographic der Braunkohle," pp. 168 ff. 



