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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 4, 



titles of iron ore in the Harz. It is often so saturated with iron, 

 that the calcareous portions are just sufficient to serve as a flux for 

 the smelting of the ore. This is well seen at the Blaue Binge Mines 

 in the Biicherberg, north of Elbingerode, of which we annex a dia- 

 gram to exhibit the contortions of the strata (fig. 6). 



There the iron rock, plunging under 

 much schist and interlaminated volcanic 

 ash or " schaalstein," is distinctly overlaid 

 towards Elbingerode by coarse gritty grey- 

 wacke, and the latter by dark schists ; the 

 whole of which are seen to be surmounted 

 by a dark limestone of totally different cha- 

 racters from that beneath. Though much 

 contorted, fractured, and perforated by 

 dykes of black porphyry and bosses of a 

 light porphyry with pinite, this upper lime- 

 stone, which is highly crystalline, passes at 

 one place into black and in another into 

 variegated coralline marble, and occupies 

 the cliff's of the gorge of the river Bode 

 near Rubiland, and its well-known caverns. 



Though fossils are rare in it, Terebratula 

 cuboides and other forms elsewhere charac- 

 teristic of the Upper Devonian have been de- 

 tected by M. Adolf Roemer ; — fossils quite 

 distinct from those of the inferior or Strin- 

 gocephalus limestone. In passing from the 

 valley of the Bode over the plateau by Hiit- 

 tenrode towards Blankenburg, the upper 

 limestone is seen to be separated from the 

 ironstone by bands of schists, grauwacke, 

 and schaalstein. 



The section (fig. 6) explanatory of this 

 succession is merely off'ered as a very rude 

 approximation ; for whilst we believe that 

 it is correct in presenting a general view of 

 the relation of the two limestones and their 

 separation, we are aware that numberless 

 features of the strata which are not visible 

 at the surface and many points of eruptive 

 rock have been omitted. 



Our chief objects, however, in calling at- 

 tention to these two limestones of Elbinge- 

 rode and the Bode-Thal are to show — 



1st. That even the lowest of them is entirely distinct from the 

 limestones of the adjacent tract on the east, watered by the Selke, 

 and which we have shown to be Upper Silurian. 



2ndly. That in following these calcareous rocks westward along 

 the southern slopes of the Brocken to the tracts between Goslar and 



