448 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 4, 



The English reader may well be surprised when he learns, that in 

 the comparatively flat region around Brunswick, where the hills are 

 of small elevation only, the secondary strata, though not in such abrupt 

 and broken walls as they occupy alongside of the granite of the Harz, 

 have still partaken of the influence of the same great movements as 

 the formations contiguous to it, though distant about twenty-five 

 miles from that line of eruption, whilst their major axis is precisely 

 parallel to the vertical masses on the north flank of the Harz. 



Thus, the strata in question, every member of which has been 

 accurately identified through its fossils, are in some instances seen to 

 have been thrown into sharp and broad undulations, by anticlinal and 

 synclinal flexures, the axes of some of which are actually overturned 

 or inverted, like many well-known examples of the Palseozoic rocks. 



In this region such movements have aifected all the deposits, from 

 the Palaeozoic to the older Tertiary, both inclusive. 



Recapitulation. — In the preceding pages we have shown, that 

 of the two chains described, the Thiiringerwald only exhibits any of 

 the oldest sedimentary rocks ; the strata containing the lowest Silu- 

 rian fossils being there underlaid, as in Great Britain and Bohemia, 

 by vast masses of slate and sandstone, in which no forms of a more 

 composite structure than Fucoids have yet been detected. These 

 bottom rocks, and the superposed Lower Silurian of that tract, were, 

 it appears, elevated into dry land, and placed during a long period 

 out of the reach of sedimentary influence ; since none of those 

 strata of the unequivocal Upper Silurian of Bohemia or the Lower 

 and Middle Devonian, which are so much developed in the Harz, are 

 to be seen in the Thiiringerwald. 



Towards the close, however, of the Devonian sera, both tracts were 

 again covered by a sea in which animals lived differing from all those 

 which preceded them, whilst the recesses of that ocean, whether 

 in this region or in the Rhenish Provinces, were spread over by 

 volcanic dejections, which were interlaminated with ordinary sub- 

 marine beds. 



These volcanic dejections ceasing, there followed other accumula- 

 tions of mud and sand, into which stems, branches, and leaves of 

 land-plants were transported, and out of which thin courses of coal 

 were formed. 



After these Lower Carboniferous beds had been accumulated, a great 

 upheaval took place over all those parts of Germany and France where 

 such strata occur, and raised up such lower carboniferous beds in 

 conjunction with those which preceded them ; the whole consti- 

 tuting the Grauwacke series of the Germans. The next sediments 

 formed on the edges of all that went before them are the feeble 

 equivalents of our Upper coal fields. These again, after partial oscil- 

 lations, were succeeded by the Rothe-todte-liegende, or Lower red 

 sandstone. Much as each range has been, at various antecedent 

 periods, subjected to eruption of igneous rocks, it was then that one of 

 the most marked of the physical revolutions of this portion of the 

 crust of the earth was accomplished, in the change of the geogra- 



