oldei' Deposits of the North of Germany and Belgium. 



245 



fossils and localities.) In the development of the strata of Herborn we have perhaps more indications of 

 a passage downwards into the Devonian system than in any of the Westphalian sections which we ex- 

 amined ; but the identity of the most characteristic species of Posidonice and Goniatites leaves no doubt 

 of the true place of these strata in the series *. 



2nd. Psammite, limestone, and shale. This group is characterized by the same fossils as at Brilon, and 

 we therefore place it as the equivalent of the Devonian system. 



3rd. Black slates of Wissenbach. Though these beds contain some fossils which might lead us to 

 place them also in the Devonian system, the presence of several characteristic Silurian chambered shells 

 and Trilobites induces us rather to regard them as the representatives of the highest Silurian rocks : at 

 all events they form the beds of passage into the lower system, and will be treated of hereafter. 



4th. Arenaceous flagstone and grauwacke (Silurian), which are widely expanded through all the hilly 

 region that stretches to the north-west. 



The geologist who, in troubled districts, is accustomed to disentagle the strata 

 containing organic remains from the trap rocks with which they are associated, 

 will have no difficulty in making out this general succession, by traversing the 

 highly undulating and picturesque tracts which diversify the valley of the Dill, 

 more especially its left bank. Although the above is a correct general view of 

 the succession when the trappean and mining rocks are left out of account, it 

 is right to give the reader a more real notion of the condition of this tract, 

 which has been so much perforated and mineralized by intrusive rocks. To do 

 this in detail would be to follow the example of M. Stifft, who, in describing the 

 duchy of Nassau by separate daily itineraries, has almost filled a thickly printed 

 volume with mineralogical descriptions of the complicated rocks which abound in 

 every hill and vale of this country. In truth, few of these masses have much 

 lateral persistence ; so that the sections on two parallel lines, not more than half 

 a mile asunder, would often difier in their detailed phsenomena. We therefore 



* The list of fossils found at Herborn, according to M. Dannenberg, is as follows : — 



Calymene concinna, Dolman. 



Ammonites expansus, V. Buch. -i 



, . Ti/r ^- I Goniatites 

 sphaericus, Martin. > 



/-» ur I hodie. 

 pnscus, Lrolajuss. J 



1. Orthoceras gracile, Blumenbach. (Said to 



be also at Wissenbach.) 



2. scalare, Bronn. 



3. fragile, Bronn. 



1. Mytilus veteratus, Goldfuss. 



1 . Posidonia Becheri, Bronn. 



2. longitudinalis, Bronn. 



3. mytiloides, Goldf. Eybach. 



1 . Avicula lepida, Goldf. 



1 . Pecten grandaevus, Goldf. 



2. ■ primigenius, Bronn. 



3. Miinsteri, Bronn. 



1. Aptychus antiquus, Goldf. 

 Terebratulae, &c. 



It will at once be perceived from this list, that the Pectens, Mytili, Posidoniae and Goniatites which it 

 contains are more near to the carboniferous than to the more ancient deposits. The only fossil said to 

 be the same as a species found at Wissenbach, is so imperfect and crushed that we are convinced no 

 identity could be established from it 



VOL. VI. SECOND SERIES. *i K 



