•6U 
SILURIA. 
[Chap. XIII. 
grey pebbly beds subjacent to this metalliferous layer, and in whicli a little 
copper-ore is also occasionally diffused, were designated ' Weiss-liegende ; ' and 
the great underlying mass of red conglomerates and sandstones, in which no 
trace of ore was detectable, received the expressive name of ' Roth-todt-liegende,' 
or the ' Red dead underlier.' These names having remained attached to such 
rocks, it is far from my wish to disturb any of them. On the contrary, in pro- 
posing the term ' Permian ' I wished simply to show that they constitute one 
natural group terminating the Palaeozoic series, as seen in the region of Permia. 
This group, distinct from the Coal-formation beneath, has for its base the Roth- 
todt-liegende, and for its summit the lowest and thinnest member only of the 
great deposit of red and variegated sandstone, known in Germany as the Bunter 
Sandstein. This view, which I applied to the German succession after my last 
exploration of Russia in 1844, was the natural result of the similarity of the 
fauna and flora of this age in both countries. 
As there is no portion of Northern and Central Germany in which the Permian 
group is more obviously separated from all underlying and overlying strata than - 
in the tracts which flank the Thiiringerwald, let us first consider its relations in 
those interesting districts. Ranging from S.E. to N.W., the chain of the 
Thiiringerwald is mainly composed, in the former direction, of those Silurian, 
Devonian, and Lower Carboniferous rocks which were formerly merged under 
the term ' Grauwacke,' and the relations of which will be explained in the 
subsequent Chapter on Germany. Towards its north-western termination 
the nucleus of the range consists of crystalline schists pierced by granitic 
rocks and greenstone, as well as by porphyries, which throw off on both 
the south-western and north-eastern faces strata composing the Permian 
group. In proceeding from the S.E. to the N.W., or along the axis of the 
chain, the observer finds that he is travelling along a ridge chiefly occupied by 
porphyries, both black and red (the latter much predominating), and consti- 
tuting the highest watershed of the wild woodlands, known as the Rennsteig. 
On either side of this central axis there are valleys, both longitudinal and 
transverse, forming deep indentations in the chain itself, in some of which there 
are exceptional outcrops of grey and dark-coloured schistose beds, occasionally 
containing a few fossil Plants, and in rare localities some beds of coal. These 
strata, differing considerably in mineral character from the Lower Carboniferous 
strata which have been raised up with the Devonian and Silurian rocks of the 
Southern Thiiringerwald, manifestly belong to the so-called Upper Coal of 
Germany. Such coal is most developed at the southern end of the Thiiringer- 
wald, where several beds of it have been reached by shafts which pass through 
vast thicknesses of overlying Roth-liegende. Towards the N. W., these deposits, 
detected at but few spots, have been found to contain coal only in the valleys 
west of Lmenau, where, in the vicinity of certain eruptive rocks, the coal-beds 
are brought near to the surface. 
The object in here alluding to these Carboniferous strata, whether productive of 
fuel or not, is simply to point out that wherever they can be observed they are here, 
as in other parts of Germany, unconformably and transgressively overlain by 
the Roth-liegende. Whilst the former, j udging from their fine lamination and im- 
bedded fossil Plants, resulted from tranquil deposition under water, the latter was 
formed during a period of great disturbance of the surface, accompanied by the 
extrusion of much igneous matter, and the powerful aqueous translation of many 
broken materials of preexisting rocks. It is by the unmistakeable signs of such 
causation that the basement strata of the Permian group are so visibly charac- 
terized, and that they differ so essentially from those which preceded them. 
