284 Professor Sedgwick and Mr. Murchison on the 



and ending with the newer Flotz rocks of the age of our green sand and chalk in 

 a position almost horizontal. 



These assumed facts were connected with the Wernerian theory, and offered in 

 support of it. Hence they obtained a currency in this country which they very 

 little deserved. In the year 1829, when we first crossed this chain, our surprise 

 was indescribable when we found that the granite of the Brocken did not occupy 

 any mineralogical centre — that it burst out at one side of the chain — that it very 

 little affected the general strike of the adjacent beds — that the whole neigh- 

 bouring series of secondary rocks was in a reversed position — and that all the 

 ''flotz " rocks on the N.E. side of the chain were highly inclined and often vertical. 

 Errors like those above alluded to, have now been long exploded in the country 

 which gave them birth. 



As seen on a coloured physical map, the high lands of the Hartz put on the 

 form of an irregular chain extending about N.W. and S.E. The greater part of 

 these high lands are occupied by old slaty rocks ; pierced, however, by innumerable 

 masses of trap, porphyry, &c., and by two great bosses of granite, both of which 

 break out on the eastern side of the chain, and come down almost close to the 

 secondary formations*. It will also be seen by a glance of the eye at a geological 

 map of Germany, that all these high lands are surrounded by secondary deposits 

 (commencing with the red sandstone, zechstein, &c., and ending with the chalk), 

 arranged with a near approach to symmetry. In one or two places on the north 

 and south sides of the chain, and also near its western extremity, the old slate 

 rocks (grauwacke) are immediately overlaid by a coal formation ; but it is so im- 

 perfectly developed, so nearly linked with the rotheliegendes, or so much concealed 

 and overlaid by porphyry, as hardly to constitute any feature on the map. 



In making a traverse through almost any part of the old slate rocks of the Hartz, 

 we find that their strike differs not much from the strike of the grauwacke of the 

 Rhenish provinces, being on the average about N.E. by E. and S.W. by W. 

 Hence the general strike of the beds by no means coincides with the longer axis 

 of the high land of the Hartz ; but, on the contrary, is more nearly at right angles 

 to it. By this structure the subordinate features of the region are greatly modi- 

 fied : and from the top of the Brocken, or any of the other high elevations of the 

 Hartz, one may trace a series of small subordinate ridges, defined nearly by the 

 actual strike, and running transversely to the principal bearing of the chain. 



On the contrary, the strike of the secondary system surrounding the Hartz 

 (however modified here and there by local causes), is on the whole about N.W. and 

 S.E. Hence it follows, that the direction of the chain of the Hartz, as laid down 



* See the south-east end of the Section, PI. XXIII. fig. 17. 



