THE RHINE AND THE MOSELLE. 



195 



as Marburg, 60 miles away. The thick tufa beds of the valley of Brohl supply 

 millstones, which are exported even to America. The huge lava stream of Kieder 

 Mendig, to the south of the lake, furnishes excellent building stones, and has been 

 quarried from the most remote age. The brewers of the neighbourhood have 

 converted some of the abandoned quarries into beer cellars. 



The volcanoes of the Eifel, with the exception of the Aspenkippel, a basaltic 

 cone near Giessen, are the only ones of Germany which have preserved their craters 

 intact. The Eoderberg, near Bonn, is the northernmost of these volcanoes. The 

 " Seven Mountains," or Siebengebirge, which face it, are of igneous origin too. 



Fig. 113. — The Siehengebirge, or Seven Mountains. 

 Scale 1 : 133,000. 



2 Miles. 



but are without volcanic vents. They are composed of trachyte and basalt, 

 and though gf inferior elevation, their culminating summit, the Oelberg, only 

 attaining a height of 1,520 feet, they have become famous on account of their 

 picturesque scenery and their legends. On the Drachenfels (Dragon's Rock), 

 which rises boldly above the floods of the Ehine, Siegfried killed the monster 

 which guarded the treasures of the Nibelungs. 



Schistose plateaux, intersected by numerous tributaries of the Rhine, extend 

 to the north and east of this volcanic region as far as the hills of Hesse. The 

 Westerwald (2,155 feet), between the Lahn and the Sieg, has partly been robbed 



