older Deposits of the North of Germany and Belgium. 291 



(grits, psammites, grauwacke, grauwacke-slate, &c.) alternating with bands of rotten-stone, containing 

 very numerous fossils, among which we collected Trilobites, Tentaculites, one or two species of Delthyris; 

 in short, the same group of fossils which characterizes the Silurian grauwacke of the Rhine. 



4. Similar masses may be followed along the same line over another series of ridges into the Ocker 

 Thai, where they sometimes appear to abut against, and sometimes even to dip under, the granite, at 

 the most northern prolongation of the Brocken. In that valley all the phsenomena are of the highest 

 interest. The relations of the rocks are shown in the deep clefts th.-ough which the Ocker finds its way. 

 The granite rises into noble pyramidal forms, and the slates are mineralized, veined, broken up, and 

 thrown into vast disjointed masses; and had we no other evidence than the great bare sections of the 

 Ocker Thai, we should conclude that the strata composing the mountains on its north side had been 

 elevated through an angle of more than 90°, and thrown into a reversed position. 



We believe, indeed, that all the beds of the preceding section are in a reversed 

 position ; that the beds extending from Rammelsberg to the granite are the oldest, , 

 and that the slate masses north of Goslar are the newest, portions of the section 

 (see the woodcut, p. 286). We adopt this supposition because it best explains the 

 relations of the mineral masses, and the distribution of the fossils ; and there is 

 in it nothing improbable, considering the vast derangements in the neighbouring 

 country. 



For example, we may take a section from the low secondary country, a few 

 miles north-east of the Ocker Thai, to the granite, and find the following series : — 



( L.) Tertiary rocks and chalk, in their natural position, and dipping from the chain of the Hartz. 

 (2.) Greensand greatly contorted, and on one side dipping toicards the chain of the Hartz. Beyond 



these disturbed beds all the formations dip towards the central mass of the Hartz, and therefore 



appear to form an ascending section. 

 (3.) Jura limestone. 

 (4.) Lias overlying the preceding. 

 (5.) Keuper overlying the lias. 



(6.) Muschelkalk and bunter sandstein overlying the keuper. 

 (7.) Slaty rocks, having on the whole nearly the same dip with the preceding, and appearing to overlie 



them. 

 (8.) Granite, abutting against, and in some places appearing to overlie, the grauwacke. 



Now it is absolutely certain that the greater part of this section (extending over 

 many miles) is in a reversed position. There is, therefore, no violation of analogy 

 in the supposition we adopted respecting the older rocks in our previous section. 



Among the fossils of the Rammelsberg range are two species of Homalonotus, one not to be distin- 

 guished from a species found at Altenahr : also Tentaculites, large crinoidal rings, several species of 

 Orthis, and two of Spirifer, all undistinguishable from species found in the Silurian grauwacke of the 

 Rhenish provinces above described. On the contrary, the small Orthoceratites and flattened Gonia- 

 tites in the black slates N.W. of Goslar appear to us to be Devonian. Moreover, this supposition agrees 



