STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 197 



where the stumps project into the coal other forms may occur. The 

 classic illustration is that at Senftenberg, described by Potonie, 

 where one sees complete evidence of destruction of a forest by a 

 transgressing bog. Kukuk's photograph of wholly similar conditions 

 is equally conclusive. Not rarely the stumps had become hollow 

 before entombment. 



No complete statement respecting the flora of the brown coals 

 can be made; the plants obtained from the associated rocks cannot 

 be utilized as they are enclosed in rocks of transported material and 

 represent, in part at least, the upland flora ; they are as inconclusive 

 as would be lists of forms found in the clays and sands which had 

 slipped down on a swamp, to one endeavoring to determine the plants 

 of peat. It is necessary to confine one's investigation to such infor- 

 mation as can be obtained from the coal itself, though in some cases 

 evidence from the enclosing shales may be utilized as illustrating 

 prevailing conditions in the immediate vicinity. 



The logs and stumps within the coal beds are almost invariably 

 conifers. In Greenland and Spitzbergen, recognizable remains are 

 rare in the coal and the logs are usually silicified ; but the associated 

 shale shows that, during its deposition, the prevalent types of the 

 immediate vicinity were conifers and other forms of acid-loving 

 plants, a swamp flora, so that swampy conditions prevailed in the 

 area whence the shale material was drawn. The Pliocene coal of 

 Hungary is crowded with stems of Sequoia; the Miocene swamp 

 of Virginia contains Taxodimn, Nyssa, Salix, Quercus and other 

 types belonging to genera familiar in recent cypress swamps. At 

 Bovey Tracey in the Eocene, ferns and Sequoia predominate, yet at 

 the bottom of one bench there is a mass of dicotyledonous leaves. 

 Fournet found a typical swamp flora in the Vion lignite, where he 

 recognized birch, juniper, fir, cherry and walnut, with sedges and 

 rushes. Daubree, near Lobsann on the Lower Rhine, found that the 

 mineral charcoal is from conifers while the peculiar fibrous coal, his 

 lignite bacillaire, which forms the greater part of some deposits, 

 is derived from Palms. At Senftenberg Taxodiuin distichwii is the 

 prevailing type in the coal, but in the upper layer are stumps of 

 Finns or Picea. Conifers and palms are the most abundant types in 



