134 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 3, 



Fig. 2. — Ideal Section of the Hirschberg. 



Hirschberg. 



a. Ideal fault and fracture. 



b, c, d. Basalt. 



e. Muschelkalk. e'. Bunter sandstone. 



/. Tertiary beds and Brown-coal. 



away under the basalt. And that is precisely the appearance which 

 the Hirschberg now presents to us. It is a remarkable fact, in con- 

 firmation of this theory, that a small Brown-coal deposit was pointed 

 out high up on the hills on the N. or N.E. side of the valley. I did 

 not visit it, and its important bearing on this question did not then 

 occur to me. 



Another feature in both of these sections is also worthy of notice, 

 as differing from other localities where the Brown-coal occurs, viz. 

 the total absence of a marine fauna in the beds above the clay. In 

 most of the other localities the marine bed is regularly superposed. 

 From its"absence here, we must conclude that this, as well as some 

 of the other freshwater lagoons and swamps where the plants grew, 

 from the decay of which the Brown- coal was formed, were situated 

 at a so much higher level than the others, that they escaped being 

 submerged when the irruption of the oceanic waters took place. 



I cannot quit this neighbourhood of Gross Almerode without 

 alluding to a remarkable hill of burnt clay, which occurs about half 

 a mile to the south of the village. Here on the summit of a ridge 

 is an isolated basaltic outburst between the Hirschberg and the 

 Meissner, but nearer the latter. At no great distance from it is a 

 vast mound or hillock of a burnt stone, which is neither more nor less 

 than the beds of tertiary clays metamorphosed into Jasper or Thon- 

 jaspis. This jasper varies greatly, not only in colour, but in struc- 

 ture ; in places having an earthy conchoidal structure, and in others, 

 one almost vitreous. There is a great diversity of opinion among 

 local geologists as to its origin, some referring it to a true geolo- 

 gical cause, others considering it as recent, and occasioned by the 

 burning of the bituminous shale or Leber-Erz. 



Looking at the spot afterwards from a distance, its form was 

 distinctly seen as rising above the surrounding ground, and re- 

 sembling the crater of a volcano. I have little doubt myself that 

 the metamorphism has been produced by geological causes, probably 

 the escape of heated gases from below ; this is rendered the more 

 likely by the vicinity of the basaltic outburst. But whatever the 



