678 



AGE OF THE BROWN-COAL. 



Fig. 724. 



[Ch. XXXI, 



Map of the volcanic region of the Upper and Lower Eifel. 

 12 3 4 5 English Miles. 



Volcanic j A. Of the Upper Eifel. r ^-p, l Points of eruption, with craters 



IMiiiJ District. | B. Of the Lower Eifel. ' ' and scoriae. 



Trachyte. 



V B. The country in that part of the map which is left blank is composed of inclined 

 Silurian and Devonian rocks. 



irregularly diffused through them. They contain numerous impres- 

 sions of leaves and stems of trees, and are extensively worked for 

 fuel, whence the name of the formation. 



In several places, layers of trachytic tuff are interstratined, and in 

 these tuffs are leaves of plants identical with those found in the brown- 

 coal, showing that, during the period of the accumulation of the latter, 

 some volcanic products were ejected. 



M. Von Dechen, in his work on the Siebengebirge,* has given a 

 copious list of the animal and vegetable remains of the freshwater 

 strata associated with the brown-coal. Plants of the genera Flabel- 

 laria, Ceanothus, and Daphnogene, including D. cinnamomifolia (fig. 

 204, p. 264), occur in these beds, with nearly 150 other plants. 



The fishes of the brown-coal near Bonn are found in a bituminous 



* Geognost. Beschreib. des Siebengebirges am Rhein. Bonn, 1852. 



