olde7- Deposits of the North of Germany and Belgium. 277 



is very clearly exhibited in a section^ we have drawn from the Schnee-Eifel to the 

 hills of Schonecken. The limestone is not, however, expanded continuously through 

 the whole elliptical area, but is thrown into violent undulations, which here and 

 there bring the lower rocks to the surface ; so that it becomes resolved into three 

 or four distinct and irregular troughs (see Map, Plate XXIV. and Sections 12 and 

 14, PI. XXIII.), all presenting the same general relations. 



Again, it has been pierced by comparatively modern volcanic vents, and is in- 

 terrupted by volcanic cones and the remnants of streams of lava ; and in some 

 places, especially on its eastern limits, it is covered up for miles together by lava, 

 cinders, scoria, and other volcanic ejections. But these materials, though they 

 greatly add to the difficulty of making out the details of the country, do not disturb 

 the general relations of the formations through which they have forced a way to 

 the surface. 



Near Miinster-Eifel, in consequence of the extreme contortions, all the forma- 

 tions, for several thousand feet of thickness and a range of several miles, are in a 

 reversed position, as indicated in the woodcut. Fig. 12. 



Fig. 12. 



Weingarten. Miinster-Eifel. 



strata in order. Strata inverted. 



7. Devonian limestones, &c. 8. Silurian grauwacke, &c. 



The figures 7 and 8 are those used in the Map to distinguish the formations. 



This anomaly must have been produced by disturbing forces which acted during 

 ancient periods, long anterior to the comparatively modern volcanic vents ; and as 

 we follow the beds along their strike, the limestone is seen gradually to recover 

 its natural position ; so that near Sotenich it occupies a trough as clearly defined 

 as the one we have indicated near Priim and Schonecken. (PI. XXIII. lag 14.) 



The limestone is of very great thickness ; for on some of its outskirts there is a succession of great mural 

 precipices, showing on one single spot several hundred feet of strata ; and how far such sections are from 

 reaching the highest beds of the formation it is no easy matter to determine. The limestone is composed 

 of two principal varieties, common limestone and dolomite ; the former not to be distinguished in its mineral 

 character from the great lower limestone of Westphalia and Belgium; the latter sometimes hard, cry-, 

 stalline, and marked by many beautiful impressions of corals — sometimes cellular and without any distinct 

 traces of bedding — occasionally like a mass that is half brecciated and half concretionary, and sometimes 

 quite earthy and incoherent, so as to resemble the pulverulent beds in our English formations of mag- 

 nesian limestone. As a general rule (to which, however, there may be exceptions), the dolomites are 



* See the Map, PI. XXIV. and Section, PI. XXIII. fig. 14. 

 VOL. VI. — SECOND SERIES. 2o 



