MODE IV. LIGNITE. 



591 



dary earths in the neighbourhood of coal mines; 

 sometimes, and even most often, in alluvial land. 

 " We shall mention, as an authentic example 

 of this variety, the earthy lignite of the environs 

 of Cologne, known in trade by the name of earth 

 of Cologne, as it is wrought at a little distance 

 from that city, near the villages of Bruhl and 

 Liblar. This lignite forms very extensive beds 

 of eight or ten yards in thickness, which are si- 

 tuated under considerable elevations. It is im- 

 mediately covered with a bed, more or less thick, 

 of rolled pebbles of quartz and jasper, as large 

 as eggs, and reposes on a bed of white argil, of 

 an unknown thickness. The bed of lignite is 

 homogenous \ but fossil vegetables are found in 

 it, very well preserved. They are, 1. Trunks 

 of trees, lying one on the other, without any 

 order, the wood being black or reddish, generally 

 compressed : they easily exfoliate, by drying in 

 the open air. Some belong to trees of the dico- 

 tyledon kind, others are fragments of palm-trees. 

 Among these, M. Coquebert-Montbret has found 

 some which are full of small round pyritic bodies, 

 resembling grains of small shot *. This wood 



" M. Heimhaa remarked in the lignite of Kalten-nordheim, in 

 Thuringia, small elongated spherical substances, resembling a pod 

 of two partitions. M. Blumenbach supposes them to be unilocuknr 

 bivalve capsules. (Journal des Mines, No. 105.)" 



