Geology of the Harz Mountains. 255 



does not occur in the immediate neighbourhood of the 

 southern flanks, but is found in a few outliers on the Ohm- 

 gebirge about 20 kilometres S. of Herzberg, which proves that 

 it once extended for a certain distance between the Harz and 

 Thiiringer Wald. The southern region has been elevated 

 more than the northern, and consequently denudation has 

 there proceeded more rapidly, and has succeeded in carry- 

 ing off nearly all the Cretaceous and a large part of the 

 Triassic formations. 



8. Final Upheaval of the Haez and Kyffhausek. 

 a. The Great Faults. 



The Mesozoic formations of the plain are abruptly cut off 

 from the Palaeozoic core rocks by an irregular line extending 

 along the northern border of the range from Langelsheim to 

 Ballenstedt. The edges of the newer rocks are in many 

 places turned up, curled back, and inverted at an angle of 

 60° or 70°, thus appearing to dip beneath the Palaeozoic series. 



That there is along this line a great fault is proved by the 

 following evidence : — 



1. The abruptness of the line of contact and steep inclina- 

 tion with which the core rocks plunge down through the 

 Secondary formations of the plain. Had there been only an 

 unconformability the Palaeozoic series would have sloped 

 gradually away below the overlapping Secondary rocks as 

 along the southern Harz border. 



2. Concealment of the lowest beds. — The Zechstein occurs as 

 a thin band between Ballenstedt and Ilsenburg at the very 

 edge of the core rocks, in the usual inverted position ; but 

 farther west, between Harzburg and Langelsheim, it is con- 

 cealed or " nipped out," and the old rocks are bounded by 

 the overljring Bunter sandstone. There is good reason to 

 suppose that the Zechstein is present here, and had there 

 been an unconformability like that along the southern edge 

 of the Harz it would have been clearly exposed. 



3. Intersection of Different Horizons. — The old rocks cut 

 across the strike of the Secondary formations from Zechstein 

 to Cretaceous, which can only be explained by a fault. 



