Chap. XIII.] KOTH-LIEGENDE AT EISENACH. 
315 
In truth, various rocks of igneous origin have penetrated the Thiiringerwald 
from a very early period; but it is only on ascending 
to the Roth-liegende that we are surrounded with 
cotemporaneous porphyry; so that, as well laid 
down on Credner's map, the northern part of the 
chain is seen to be, to a great extent, occupied by 
red porphyries, which rise to the highest central 
summits, such as the Inselsberg and Schnee-Kopf, 
the latter 3300 feet above the sea. It was there- 
fore in this, the earlier part of the Permian era, that 
those grand protrusions or eruptions took place, 
& from S.E. to N.W., which obscured the ancient 
Jj physical direction of the slaty rocks that trend 
op from N.E. to S.W., and determined the notable 
% fact that the axis or watershed of the ridge ranges 
ai from S.E. to N. W., or at right angles to the strike 
o of the old slaty ridges. 
3 The porphyries which ushered in a new series 
of deposits are immediately flanked on either side 
of the Thiiringerwald by the Permian group, which 
is interposed between the older rocks and the 
tranquilly deposited Trias. Now, at the north end 
i ^ ffigOTV 2 of the Thiiringerwald, where all such older rocks 
subside, as at and near the town of Eisenach, the 
core of the chain is composed exclusively of a 
splendid development of Roth-liegende, succeeded 
on either side by all the other members of the 
Permian group, the whole being symmetrically 
united. Here, in the deep valleys excavated in the 
Roth-liegende, the tourist meets with picturesque 
cliffs amidst luxuriant foliage ; and here it is that 
the geologist is specially invited, with Credner's 
map and Senft's descriptive work in his hand, 
«| to study the characters of the lowest member of 
§ Permian deposits, which, in this neighbourhood, is 
J2 expanded to the vast dimensions of at least 4000 
£ feet. This fact has been ascertained by boring 
P3 through the lowest visible portions of this great 
<a accumulation in search of coal, to the depth of 
^~ 2600 feet in nearly horizontal strata, and by adding 
°„ to the subjacent red sandstone, shale, and pebble- 
^ beds the thickness of the overlying deposits which 
are exposed in this hilly tract. In the lowest strata 
bored through were found fragments of silicified 
Plants (stems of Araucarites, &c), similar to those 
which will presently be spoken of as occurring in 
the escarpments of the Kyfhauser, to the south 
of the Harz. 
The reader will therefore understand that, thick as 
the Roth-liegende appears to be in the accompany- 
ing woodcut, which I prepared in 1857 after reexa- 
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