148 | GEOGNOSY AND GEOLOGY. 
The remarkable table mountain at the Cape of Good Hope (Pl. 48, Fig. 
26) consists in great part of this rock. The succession of the strata in the 
Ardennes is very difficult to determine, their features being much obscured 
by the numerous contortions and undulations ( pl. 46, fig. 5). By reason of 
these flexures, many strata are brought several times to light on a section. 
so that it would be very erroneous to consider them as so many distinct 
layers. It is continued in the Rhenish transition rocks, as shown in profile 
of the section just referred to. 
The Silurian system is indicated by 8; upon this rests the Devonian, D. 
it has been broken through by the voleanic mass V, and upheaved on both 
sides. The more recent Floetz is seen resting against the right side, as the 
carbonate of lime k, carboniferous sandstone ks, the anthracite st, and the 
Vosges sandstone Vog. The Eifel, the Hundsrtick, Taunus, and the Rothhaar 
mountain, are heights which form the continuation of the Ardennes. This 
inay be easily followed on the geognostical map, Pl. 46, fig. 6. Single 
portions of the Devonian rest on the Silurian near Kronenburg, which appear 
to have stood in connexion with that in the West Forest, and near Dussel- 
dorf. Upon the Devonian there rests a narrow strip of the carboniferous, 
at Arnsberg the carbonate of lime, at Iserlohn the carboniferous sandstone, and 
at Hattingen and Mihlheim the stone coal, which is also seen at Kaisers- 
lautern. Next follows the Trias, which begins not far from Brilon, passes 
by a small strip of the Devonian in the vicinity of Marburg and Giessen, 
and ends to the north of Homburg. It again appears at Bittburg. Single 
vortions of the Vosges sandstone occur at St. Wendel and to the northeast 
of Birkenfeld. Then follow chalk rocks, which occur in the north at 
Bochum. Their place is supplied in the south by tertiary masses at 
Wiesbaden and Mayence, in the west not far from Bonn and Gemiind, 
upon which rest alluvial masses at Frankfort, Darmstadt, and Dusseldorf. 
Voleanic masses break through the strata at Andernach and Coblentz, as 
also in Siebingebtirge, and in the West Forest. 
The other side of the Ardennes appears to be formed of the Hartz and the 
Thiringerwald, a geological chart of which is presented in fig. 9. The 
Hartz, whose greater part consists of grauwacke, is broken through in the 
middle by granite, and by small masses of porphyry, which play a greater 
part in the Thiringerwald: The transition limestone is not inconsiderable 
in the Hartz, and constitutes at Grund and Rtbeland entire mountains 
belonging to the Devonian system. In proportion as we recede from the 
Hartz, the strata become more recent: we pass over the carboniferous, the 
todtliegende, the zechstein, the variegated sandstones, the muschelkalk, the 
keuper, the lias, the oolite, the quadersandstone, the chalk, tertiary masses, 
and diluvium. The same order of succession may also be followed from 
the Thtiiringerwald. 
Fossirs or tue Transition Stare Rocks. The fossils of the Silurian 
and Devonian nearly all belong to forms different from those of the present 
era. Some of the most characteristic are figured on pl. 37, principally after 
Elie de Beaumont. 
578 
