I 55. BROWN COAL FORMATION. 279 



various qualities, disposed in distinct beds, and intermixed 

 with argillaceous matter. The breadth of the ridge of low 

 hills, formed by this assemblage of strata on the left bank of 

 the Rhine, is from three to five miles, its elevation varying 

 from 50 to 200 feet. 



The lignite occurs in the following states : — 1. A black 

 earthy and pulverulent substance. 2. Concretionary masses, 

 with leaves and fragments of wood. 3. Wood in various 

 degrees of bituminization, and of shades of colour from a 

 light-brown to jet-black. 4. Very finely laminated masses 

 of bituminous matter and clay, of a dark chocolate colour, 

 and separating into elastic flakes, as thin as paper, whence 

 its name ])apierkohle ; this substance is so highly bitumi- 

 nous as to burn with a bright flame. The wood is gene- 

 rally in small fragments, but stems of large trees, some- 

 what compressed, occasionally occur ; in some instances the 

 trees are imbedded in an upright position, having the 

 roots attached, and the stems passing through several beds 

 of lignite. In many examples the wood is so little changed, 

 that, like the timber of our peat-bogs, it is employed in 

 building ; in others it is highly pyritous, that is, impreg- 

 nated with sulphuret of iron, like the fossil vegetables of the 

 Isle of Sheppey. 



Mr. Horner is of opinion that there were extensive fresh- 

 water lakes, in the sediments of which trees and plants, 

 drifted by land-floods, were engulfed ; and that volcanic 

 eruptions were simultaneously going on, in the same manner 

 as in the modern submarine volcanoes. There is a great 

 fault, or dislocation, in this brown coal formation, which he 

 suggests may be attributed to a powerful and sudden volcanic 

 explosion, that probably occasioned the elevation of the Sie- 

 bengebirge, and raised up that portion of the coal-beds which 

 reposes on the flanks of those peaks. The gravel covering 

 the lignite, must have been strewn over the plain previously 

 to this elevation, for it is found on both sides of the river at 



