EXPLANATION OF THE PLATES AND WOODCUTS. 



Fig. 11. Section from Dietz on the Lahn to the Rhine, south of Coblentz. It exhibits the rise 

 from beneath the Devonian hmestone of a great slaty series, and from beneath these de- 

 posits of Silurian greywacke : p. 244 et seq. 



Fig. 12. General section of the Ardennes, to show the relations of the Eifel on one flank and 

 of the Liege country on the other to a central axis of older slaty rocks. 



The youngest deposit in the Eifel is the equivalent of the South Devon limestone, and 

 it passes into Silurian greywacke. On the Belgian side of the Ardennes the strata are 

 frequently inverted, as pointed out by M. Dumont in his work on the province of Liege, 

 and as represented in this section, fig. 12 : p. 261 and p. 267 et seq. 



Fig. 13. Actual section across a portion of the Eifel district, much invaded by volcanic erup- 

 tions. The same sequence of the strata as in the preceding sections may nevertheless be 

 detected: p. 261 and p. 267 ^t seq. 



Fig. 14. Section from the Ardennes on the N.N.W. of the Schnee Eifel to the country on the 

 S.S.E. of Schonecken. It exhibits a considerable thickness of fossihferous Silurian grey- 

 wacke, passing upwards by alternations of shale and calcareous strata into limestone of 

 the age of that of South Devon. The uppermost mass of limestone is the dolomite so 

 prevalent in the Eifel and well displayed near Schonecken. Near the latter is a strongly 

 marked Une of fracture : p. 267 ^t seq. 



Figs. 15. and 16. These sections represent the structure of the country south of the Fichtel- 

 gebirge in Upper Franconia : p. 298 et seq. 



The first (fig. 15.) proves that the age of the chief limestone of that district (the oldest 

 fossihferous beds of Count Munster) is the same as that of the Devonian Hmestones, for 

 it passes upwards into deposits containing mountain limestone fossils : p. 298. 



The second section (fig. 16.) shows that the limestones of Elbersreuth and Schubel- 

 hammer (so celebrated for their organic remains) are members of the Devonian system, 

 but affected by eruptions of trap, and greatly dislocated : p. 300. 



Figs. 17. and 18. are sections through districts connected with the Hartz. 



The first (fig. 17.) presents a general section from the Brocken to the plains of Bruns- 

 wick, but many local details and faults are omitted. Its chief object is to exhibit an axis 

 of Devonian limestone, much altered by intrusive porphyiy, and overlaid on each flank by 

 shale and impure limestone, highly charged with iron ore, as well as associated with 

 numerous bands of bedded, contemporaneous trap ; there is also a large development of 

 schaalstein. The shales and schists in contact with the granites of the Brocken and the 

 Rosstrappe are much altered and inverted, and portions have been severed and carried 

 up on the points of eruption. All the secondary strata, from the bunter sandstein to the 

 chalk inclusive, have been also thrown into vertical or inverted positions : pp. 284, 292. 

 Fig. 18. exhibits an ascending section from the Devonian limestone of Hiibigenstein 

 and Griind, to the overlying mining tract of Clausthal : p. 288. 



Plate XXIV. 



Map of the Rhenish provinces reduced from the great map of Hoffmann as improved by many 

 recent observations of Prof, von Dechen and M. Erbreich, and communicated to the au- 

 thors by the former. The palaeozoic rocks are coloured according to the classification of 



