Geology of the Harz Mountains. 257 



border, but to avoid exaggeration let us say 2000 feet. 

 The great fault must therefore have produced at this locality 

 a relative vertical displacement of no less than 3000 feet 

 — an amount probably much smaller than that of the up- 

 throw in the neighbourhood of Blankenburg, Wernigerode, 

 or Ilsenburg, where the maximum effect would be produced. 



h. Character of the Upheaval. 



The upheaval which gave birth to the Harz, as we now 

 know it, thus took place very simply. During the earth 

 movements which affected Europe at the close of the 

 Secondary period, a great corrugation of this part of the 

 earth's crust took place along lines running approximately 

 W.KW. and E.S.E., as shown by the trend of the Harz, 

 Thuringer Wald, and other ranges, and by the flexures of the 

 Mesozoic strata in the plains between them. 



The final upheaval of the Harz was a process of quiet 

 elevation of the area en masse, and quite different in character 

 from the first upheaval in the Carboniferous period. The 

 metallic veins formed before the emergence of the modern 

 Harz appear to have remained undisturbed during the up- 

 heaval, and there is no evidence of any folding or relative 

 shifting of the core rocks having accompanied it. The last 

 upheaving force here acted in a direction nearly at right 

 angles to that of the first, and was less violent in the local 

 folding it produced, but was felt over a much larger part of 

 the European area. 



In the region now known as the Harz a great swelling up 

 of the earth's crust took place. A line of weakness running 

 along the northern side of the district gave local relief to 

 the pressure from below, and allowed the whole area to rise 

 like a huge trap door on a level stage, hinged at the south, 

 and free to open upwards on the north. The Mesozoic rocks 

 on the south side of the dislocation would be quietly elevated 

 on the back of the Palaeozoic mass beneath. On the north 

 side they remained stationary or sank downwards, but were 

 bent up and curled backwards along the line of fracture by 

 a pressure like that produced by a great wedge driven up- 

 wards from below. 



VOL. VIII. R 



