632 STEVENSON— FORMATION OF COAL BEDS. [November 3, 



material suggests that these coal beds originated in a mass of de- 

 cayed swamp vegetation. Locally, portions of the mass have lost 

 the woody structure and resemble the higher grades of lignite, shad- 

 ing into bituminous coal. But, as a whole, this coal is in its youth 

 and Eldridge thinks it doubtful if a younger example of coal can 

 be found — peat excepted. 



Darwin^^" saw in Chili a petrified forest in Tertiary rocks. 

 Eleven trunks were silicified and 30 to 40 were converted into 

 coarsely crystallized white calcareous spar. They had been broken 

 off abruptly, the vertical stumps projecting a few feet above the 

 ground. They were from 3 to 5 feet in circumference. "The vol- 

 canic sandstone, in which the trees were embedded and from the 

 lower part of which they must have sprung, had accumulated in 

 thick layers around their trunks ; and the stone yet retained the 

 impression of their bark." 



The ]Miocene brown coal deposit at Gr. Raschen near Senften- 

 berg has been referred to on a previous page : Potonie's^^^ descrip- 

 tion is that of a buried forest closely resembling those of New Jer- 

 sey. It is very similar to the buried cypress swamps and forests of 

 the southern United States, for Taxodium disticHum is the dominant 

 tree. As in the white cedar and cypress swamps, one finds in this 

 brown coal deposit. 10 meters thick, successive generations of trees. 

 The fuel is mined in open cjuarry and Potonie's plate shows the erect 

 stumps distributed on the surfaces of several benches as they stood 

 in the old forest, while the walls of the benches exhibit prostrate 

 trunks in the intervening spaces, precisely as one sees them now on 

 the surfaces of the forested swamps in America. These stumps, 

 one third of a meter to nearly 4 meters in diameter, are, like those 

 described by Cook and others, rooted in the peat, now converted into 

 brown coal of excellent quality, as good as that which will come 

 from the Dennisville peat in New Jersey. 



There are few recorded observations of buried forests in the 

 Mesozoic rocks ; in very great part, those rocks were marine : The 



^^" C. Darwin, " Journal of Researches," New York, 1846, Vol. II., pp. 85. 



'^' H. Potonie, " Ueber Autochthonie von Carbonkohlen-Flotzen und des 

 Senftenbergcr Braunkholen-Flotzen,'' Jahrb. k. preuss. geolog. Landesanstalt., 

 1895, Separate, pp. 19-24. 



230 



