238 Professor Sedgwick and Mr. Murchison on the 



1. The upper mass, which rises from beneath the " kiesel schiefer" (or mountain limestone) group 



and overlies the ffj-eat limestone, consists of dark shale with thin calcareous courses, in which 

 occur small Goniatites and flattened Orthoceratites. These bands are surmounted by the red 

 shale, grey psammite, black flinty limestone, and carbonaceous sandstones before described. 



2. Black flag-like limestone, — few fossils (^Ter. aspera, Devonian variety). 



3. Dark limestone with white veins, containing numerous fossils, among which we collected a portion 



of the Trilobite, Brontes fiahellifer (Goldf.), Orthoceratites, a small Lingula, and a Producta, 

 like the variety of P. depressa * which occurs in Devonshire. 



4. Great limestone of lighter grey colour, several hundred feet thick, characterized by abundance of 



Strigocephali, the shells of which chiefly appear in sections of white calcareous spar, associated 

 with various corallines, especially Favosites ramosa, F. Spo7igites, Cyathophyllum, &c. 



5. Dark-coloured lower limestone, in which we no longer trace the Strigocephalus, but find abun- 



dantly Terebratula aspera, as on the lower beds at Eilpe near Hagen. 



The descending section (as seen in PI. XXIII. fig. 4) which is exposed on the 

 right bank of the Lenne, in proceeding from Griine towards Altena, passes through 

 a series of schists, flagstones, calcareous shales, sandstones, &c., in which new 

 types of fossils begin to show themselves. These strata (to be considered more in 

 detail in the sequel) will be shown to lie on the parallel of the upper Silurian rocks 

 of England. 



We refer to the annexed lists of the fossils of this great calcareous group above 

 described, which will be seen to differ entirely from that of the overlying series. 



In the upper limestone of Cromford, and in the thin-bedded black limestones, 

 shales and flinty slates which take its place, we find the most characteristic fossils 

 of the carboniferous limestone of England, and the fossils of the black culm- 

 limestone of Devonshire ; from which we infer that this culm-limestone is only 

 a peculiar development of the carboniferous limestone. But in the lower lime- 

 stone above described, the characteristic organic remains are those of the South 

 Devon limestone, which, in a previous memoir, we have shown to be of higher 

 antiquity than the black culm-limestones f. Thus are we enabled, through the 

 evidence of the foreign sections, to supply geological links which have not yet been 

 so clearly found in England ; and thereby we establish comparisons which must, 

 we presume, be of general use in the classification of the older rocks of Europe. 



Devonian Rocks in their Eastern prolongation to Meschede and Brilon. 



In its range to the eastern parts of Westphalia, the zone of Devonian rocks 

 which we have described undergoes great lithological changes. The shale beds 

 become gradually harder and more schistose, and at length pass into roofing slates ; 

 and the limestones (instead of forming a great, well-defined and thick-bedded zone) 



* Orthis rugosa. Note by MM. de Verneuil and d'Archiac ; see &ho posted Tabular List, 

 t See Geol. Trans., vol. v. p. 649 et seq. 



