270 M. DE Ronnard's Notices 



Let it be recollected that many of the granitic rocks of 

 the Hartz are true syenites, that some others are proto- 

 gynes^* and that protogynes and syenites are often consi- 

 dered as belonging to the transition class. Let us also consi- 

 der, with M. Raumer, that the environs of Dohnain Saxony, 

 present above a schistose formation containing beds of grey- 

 wacke, rocks analagous to those which accompany the Hartz 

 granite, among others the hornfels, and lastly the granite 

 itself. Let it be added that there are many among the 

 mineralogists inhabiting the Hartz, who, while they believe 

 in the primordial nature of the granite, do not consider the 

 hornfels, the quartz rock of the Bnichberg, and the schists 

 of Andreasberg, as of primitive formation.t Lastly, let it 

 be recollected that M. Freisleben thought he found frag- 

 ments of gneiss in the granite of the Brocken.J 



The general direction of the beds, from W.S.W. to E.N.E. 

 is now considered to be, if not altogether constant, at least 

 very general in the ancient rocks of the north of France, 

 Belgium, and the north of Germany. I have elsewhere || 



I do not conceive that the granite, constituting the mass of the Brocken 

 and its environs, can be regarded as much more elongated from N. to S. 

 than from E. to W. ; but it is true that at the eastern extremity of the 

 Hartz, the granite of Rosstrapp, of the Ramberg and Auerberg (especi- 

 ally the first and third) are situated nearly south from each other. I do 

 not know if this circumstance is sufficient for M. Germar's opinion : as 

 to his ideas vpith regard to the correspondence of the granitic rocks of 

 the Hartz and Thiiringervvald, he only presents them as a sketch not 

 founded on precise observations. Not being acquainted with the Thii- 

 ringerwald, I can neither support nor oppose this resemblance, which is 

 very different from what I am about to state; I shall only observe that 

 it appears to me opposed to the received ideas of the general dispositioa 

 in Europe, either of rocks of the same nature, of the great lines of ele- 

 vated countries, of low countries, of lakes, or inland seas. 



* A name given by M. Jurine to the granitic rock of Mont Blanc, des- 

 cribed in a previous part of this section. (Trans.) 



+ M. Germar observed at the old mine of Gliickauf, near Andreasberg, 

 a well characterized greywacke slate. He also considers that all the 

 schistose rocks of this canton are not of primordial formation, but con- 

 temporaneous with the greywacke of the remainder of the Hartz. 



J See Geognosie de Reuss, t. 2, p. 211. 



II Sketch of the coal measures of the north of France, &c. Journal 

 des Mines, No. 156, p. 418, &c. 



