1855.] MURCHISON AND MORRIS THURINGERWALD. 419 



Credner leaves it to be inferred (in some of the sections accom- 

 panying his map) that this coal of the Thiiringerwald is conformable 

 to the overlying red conglomerate and sandstone, there are tracts, 

 even in this region, where the two rocks are unconformable ; and 

 Gutbier has shown that this is decisively so in the environs of 

 Zwickau. 



At Manebach, near Ilmenau, several thin seams of coal, the chief 

 of which is about three feet thick, are extracted by horizontal galleries, 

 on the east side of a deep valley, from beds of shale overlying gritty 

 sandstone of dark and light colour, the last very thick-bedded, and 

 the strata dipping N.E. about 13°. These are traversed and covered 

 by rocks of igneous origin. In several spots the intrusive rock is a 

 red quartziferous porphyry ; at another place, about a quarter of 

 a mile distant, the coaly strata are cut off by a granite or granitello, 

 which, if it does not exhibit passages into porphyry, is at all events 

 of very varied composition, even in the space of a few yards. At a 

 third point the intrusive rock is a black porphyry (melaphyre) . 



These rocks have all been erupted through the coaly sediments, 

 and have in great part overflowed them ; for the red porphyry in 

 particular forms the mass of the hill capping the coal strata. 



In traversing the northern Thiiringerwald on two parallels, we 

 observed that the coal strata hardly rose up to points of any con- 

 siderable elevation on the sides of the valleys ; but usually outcropped 

 from beneath those red rocks (the Rothe-todte-liegende) and the 

 associated porphyries to which we shall presently allude. 



At the southern extremity of the chain, north of Kronach, we had 

 the clearest evidences of the coal being worked entirely from beneath 

 accumulations of the Rothe-todte-liegende, of a thickness probably 

 of 2000 feet, which, being inclined at high angles in a great recess in 

 the older rocks, permits the coal strata (which are only visible in 

 partial outcrops) to be worked by shafts of moderate depth. 



In visiting two of the spots where coal is extracted, we could not 

 satisfy ourselves as to the true character of the strata which there form 

 the base of the coal deposit. According to M. Biittner of Kronach, 

 one of the superintendents of these works, the lowest carbonaceous 

 rock, abutting against the *' Younger Grauwacke" (there Upper 

 Devonian and Lower Carboniferous rocks), is a jaspidean claystone, 

 which is followed upwards by a sort of conglomerate containing frag- 

 ments of older porphyry. The immediate support, however, of the 

 coal-bearing strata is a whitish coarse grit, not unlike one of the beds 

 near Ilmenau. Associated with the coal, and forming its roof, there 

 is a finely laminated indurated shale, in parts resembling the *' black 

 bat," so well known in Staffordshire and other English coal fields. 



At Stockheim and Neuhaus, which we visited, and where the coal 

 is raised in a shaft about 250 feet deep, the chief bed of coal was 

 estimated at about 12 or 14 feet in thickness. The coal strata 

 are much disturbed, and inclined, at angles varying from 80° to 25°, 

 60° to 50°, and thence to 25° near the surface, where they underlie 

 the Rothe-todte-liegende or red rock. It is probable that part of 

 this thickness may be in great measure due to an oblique section of 



