older Deposits of the North of Germany and Belgium. 257 



may perhaps have been heaved up by the basaltic eruptions of the spot, which 

 have indeed converted large portions of the arenaceous deposits into quartz rock. 

 (See PI. XXIII. fig. 8.) 



Were it desirable, we could give many transverse sections through the lower 

 groups of the Rhenish formations ; but the details of any one of them would be 

 found to differ considerably from those of other parallel traverses made even at short 

 distances. We therefore conceive that by a reference to one ideal section, in which 

 the prominent data are generalized and grouped, we shall better explain the general 

 relations of these older rocks than by entering into a multitude of incongruous 

 details: and our list of fossils, with their localities, will assist in verifying the 

 respective ages of the deposits, from whatever data they may have been previously 

 made out. 



In the tract near Dillenburg the grauwacke which rises from beneath the slates 

 of Wissenbach (PI. XXIII. figs. 6 and 7), and occupies the high country extending 

 north-westward in the direction of Siegen*, is characterized by the same fossils 

 which 'abound in it in so many other parts of the high regions of Nassau and Rhenish 

 Prussia. Two species of Trilobites (one of which is not to be distinguished from 

 Calymene Blumenbachii, and the other, which approaches closely to Homalonotus 

 Knightii) are found in it along with numerous casts of shells. The shells are very 

 abundant at Haiger-Suhlbach, Wildenstein, and Sossenbergf, and are associated 

 with several species of Orthis (one of which closely resembles 0. orbicularis), with 

 Orthoceratites, and with several corals of the Silurian system, some of which (such 

 as Favosites polymorpha) are also found in the overlying or Devonian rocks. 



Again, there exist the clearest proofs, from the consistent evidence of sections, 

 that other strata, inferior to the Wissenbach group, form the greater bulk of the 

 grauwacke system of the Rhine. These consist of various bands of sandstone of 

 reddish, yellowish, greyish, and whitish colours, alternating with hard grey schists, 

 immediately underlying the fossiliferous flagstones and slates last described. Every 

 traverse from the northern ed^e of Westphalia to the territory of Nassau demon- 

 strates a similar succession. In ascending the banks of the river Lenne from 

 Limberg to Altena, we are presented with a fine sequence of these rocks, with occa- 



* M. Erbreich, chief mining engineer of the district of Siegen, and an excellent geologist, was our guide 

 through this tract, and from him we obtained many of our best fossils. We have already alluded to this 

 gentleman as the associate of Von Dechen in preparing the great geological map of the Rhenish provinces. 



\ M. StifFt enumerates many other localities in Nassau at which fossils occur. Among these are 

 Sprinzen on the Wisper, Espa, Wisperfeldt, Hasselbron, Nievern, Altenhauser, Buch Wahlenberg, 

 Wolfsberg, Burschen near Oberrossbach, and the Kahrer-kopf, between Steinbruch and Mandeln. We 

 regret not to have heard of these localities before we traversed this region. It would appear, how- 

 ever, that the fossils are chiefly repetitions of the forms we have so often alluded to. 



