2C8 M. DE Bonnaud's Notices 



The rocks of hard schist and flinty slate in the environs of 

 Andreasberg, which are also considered as of primitive for- 

 mation, certainly appear in some places to rest immediately 

 on granite or on the horvfels covering the granite ; but their 

 general dip, as well as that which can be observed with res- 

 pect to the quartz rock of the Bruchberg, is nearly that of 

 the greywacke situated to the west of the Bruchberg, and 

 which would consequently appear to be beneath them. M. 

 Schultze notices similar rocks in the eastern part of the 

 Hartz, which appeared to him to be of contemporaneous 

 formation with the greywacke, and to present many passages 

 into and mixtures with the latter. Many local observations 

 tend equally to make us doubt the constant anteriority of 

 the Hartz granite, relatively to the other rocks that have 

 with it been regarded as primitive. 



Ascending the valley of the Use, we find steep granite 

 rocks one league from Ilsenburg, known by the name of 

 Ilsensteinsklippe ; situated opposite each other, on both sides 

 of the valley, which becomes narrow as it approaches them, 

 and expands above them, they appear to form part of a 

 granite bed situated in the midst of different rocks which 

 have less resisted the action of the waters. Lasius has long 

 since shewn that these rocks exhibit very marked traces of a 

 stratification parallel to the general stratification of the Hartz 

 rocks» Ascending higher up the valley, schistose and quart- 

 beds of the north of Germany, and particularly those of the Hartz, hav- 

 ing a general direction from W.S.W. to E.N.E. should not be deranged 

 in their dip by the salient masses of the more ancient crystalline rocks 

 they meet with ; that thus they would not present round these primor- 

 dial masses the variety of dip, which is erroneously required as a proof 

 of their superposition, and that they might occur dipping towards the 

 granite, on the west and north of the granitic mountains, as is seen in 

 the Hartz, without our being able from that circumstance to deduce any 

 probability of contemperaneons formation. The force of this reason- 

 ing appears to me much diminished from the examination of the Iberg 

 mountain, where, as we shall presently see, the greywacke presents very 

 different sides of the transition limestone; and it appears very difficult 

 to conceive why the primordial masses have not produced on the transi- 

 tion slates as much effect as the calcareous masses that are scarcely an- 

 terior to these slates. 



