140 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail, 3, 



of things having probably begun earUer, as shown in the Westeregeln 

 Sands, lasted somewhat longer, until this region (also undergoing the 

 influence of the elevatory action, though in a smaller degree) was 

 likewise raised above the level of the sea, and became covered with a 

 low swampy vegetation, the decay of which produced the overlying 

 brown-coal deposits of Brandenburg and Prussia. 



I stated in my former paper {loc.cit. p. 288), that I could not admit 

 the hypothesis of theMayence basin havingbeen an insulated inland salt 

 lake without communication with the northern ocean. I endeavoured 

 very imperfectly, not being acquainted with the geological features of 

 the neighbourhood of Cassel and other places, to show that some com- 

 munication with the Northern ocean, round the eastern flanks of the 

 Taunus, must have existed, and that the subsequent closing up of 

 this northern channel might have been brought about by the elevation 

 of the Vogelsgebirge (erroneously stated Fichtelgebirge in my former 

 paper, I. c. p. 294), or by other basaltic outbursts. A more accu- 

 rate knowledge of the geology of Hesse Cassel convinces me of the 

 great probability of this opinion. A line of volcanic outbursts, per- 

 forating the surface in a thousand spots, extends from the neigh- 

 bourhood of Frankfort and of Hanau, considerably to the north of 

 Cassel, elevating the stratified beds to a considerable height, and 

 thus causing a complete barrier to the connection between the 

 Northern Ocean and the waters of the Mayence basin. These ter- 

 tiary deposits are now consequently found in some places at an 

 elevation of 1000 feet above the sea, as near Dransfeld ; and, judging 

 from the configuration of the country and the elevation of the Bunter 

 Sandstein, they were probably raised to a still greater height, although 

 almost entirely removed by subsequent denudation ; while in other 

 places they are found at a much lower level. Indeed the same 

 argument will apply on a large scale to these volcanic outbursts and 

 to the elevation of the Bunter-Sandstein, north of Cassel, which I 

 have already used respecting the outbursts of the basaltic plateau of 

 the Hirschberg and the surrounding district (see fig. 2, p. 134). 



We have here an instance on a large scale, and accompanied by 

 the same results, of the phaenomenon already alluded to respecting 

 the position of the basaltic plateaux of the Hirschberg, Meissner, and 

 other places. I showed how the occurrence of these basaltic rocks 

 in their present positions was owing to the molten matter having 

 been forced up through the crevices in the troughs of the undulations 

 into which the secondary formations had been thrown. Now the 

 Bunter-Sandstein, north of Cassel, rises to a considerable elevation, 

 in some places as much as 1000 feet above the sea, whilst between 

 Cassel and Frankfort its elevation is comparatively slight. We may 

 therefore consider the portion to the north of Cassel as representing 

 on a large scale the anticlinal, while that to the south represents the 

 synclinal portion of a vast undulation. This is confirmed by the dip 

 of the Bunter-Sandstein, north of Cassel, which is to the south, 

 dipping under the Muschelkalk between Cassel and Wilhelmsh5he. 

 When the basalts subsequently burst forth, they found a readier 

 passage through the lower or synclinal portion, than through the 



