older Deposits of the North of Germany and Belgium. 295 



became calcareous, and a dark-coloured limestone (with the same strike and dip) 

 crossed the valley. We found a few encrinital stems in it, but no good character- 

 istic fossils. Further in the descending traverse were many masses of hard grau- 

 wacke of various colours, generally grey or greenish grey, and sometimes altered, 

 extremely jointed, and interrupted by projecting masses of trap. 



After several undulations near the mouth of the gorge the prevailing dip is re- 

 versed to the N.W. ; and the older rocks are overlaid unconformably by red con- 

 glomerate, coal beds, red sandstone, &c., which dip, from the upturned edges of 

 the slaty rocks, towards the low country. The coal has been worked extensively 

 all the way from Meisdorf to Ballenstadt, and is undoubtedly subordinate to the 

 red conglomerates and red sandstones associated with it. Its relations are very 

 clear, not being obscured, as at Ilefeld {ante, p. 286), by masses of eruptive 

 porphyry. 



From the structure of the slate beds on the Selke, the rarity of organic remains, 

 and the absence of carbonaceous stains and impressions of plants, we concluded 

 that the system of rocks on this traverse belonged to the older or Silurian grau- 

 w^acke of the Hartz. 



We afterwards made a complete traverse of the chain by Ballenstadt, Magde- 

 sprung, Hartzgerode, and Stolberg, and were accompanied by Mons. Zincken to the 

 Schnechenberg (near Hartzgerode) , where a dome-shaped concretionary mass of 

 limestone, fifty or sixty feet thick, appears among the slates. It is dark grey and 

 bluish grey, with many curved contemporaneous veins. The bottom of it passes into 

 the slates ; and there are foliated slaty portions through its mass ; but some of the 

 larger subordinate concretionary masses will take a polish, and are used for marble. 

 We remarked in it some fragments of encrinital stems, and one or two obscure 

 traces of small bivalves ; but the fossils are very rare. 



It appears, therefore, that between Ballenstadt and Hartzgerode there are three 

 or four independent concretionary masses of limestone, nearly on the same line of 

 strike, but with relations far too obscure to offer any good base line for the sec- 

 tions in this district of the Hartz. We have the authority of Mons. Zincken for 

 asserting, that to the S. and S.E. of this line no limestone has yet been discovered, 

 and that the prevailing rocks have the same general characters, and probably be- 

 long to the same age with those we remarked in the gorge of the Selke*. 



* Since we left the country M. Zincken has forwarded to us drawings of Trilobites from this region, 

 which induce us to consider the rocks of this southern end of the Hartz as a part (probably the lower) 

 of the Silurian system. 



2 q2 



