236 Professor Sedgwick and Mr. Murchison on the 



which we now proceed to describe. The chief mass of these rocks forms the 

 great calcareous zone of Westphalia, and is seen in numerous quarries in the 

 environs of Mettmann, near Dusseldorf, where it crops out in highly inclined, 

 broken, and undulating strata, and it is continued to Elberfeldt, where it oc- 

 cupies the northern and north-eastern suburbs of the town*. It is thence pro- 

 longed in a ridge by Barmen, whence it is expanded by undulations into two zones, 

 which range to the north of Schwelm and reunite in the neighbourhood of Hagen. 

 From that place to Iserlohn the limestone continues to increase in thickness, 

 and rises into bare precipices, occupying prominent ridges between the wooded 

 hills of the lower carboniferous strata on the one hand, and the mountains of older 

 rocks of shale and sandstone (Silurian grauwacke) on the other. 



From Iserlohn, in its prolongation to the E.N.E., this Umestone is much ex- 

 panded between Menden and Balve, where it forms the great sahent promontory be- 

 fore alluded to, round which the overlying formations mantle (see map, PI. XXIV. 

 colour 7). From that point it is deflected nearly to Neunrade, whence it stretches in a 

 long attenuated band to the neighbourhood of Meschede ; and, after being lost for a 

 certain distance, reappears to the north-east near Brilon. Before it reaches that 

 place, it again increases in thickness, and is expanded over a large area by vast 

 undulations, one of which brings it out to the surface at Warstein, among the 

 superior strata, several miles to the north of its more general range. 



In traversing the inferior rocks we find the same limestone occupying a great 

 trough or parallel zone near Attendorn. Other bands of it (though in very differ- 

 ent lithological condition) occur near Dillenburg ; and finally it breaks out in 

 great masses on both banks of the Lahn, striking through the heart of the grand 

 duchy of Nassau. It would be difficult to induce any one, who judged from mere 

 mineral characters, to comprehend how all the courses of limestone, here 

 briefly enumerated, which appear on different zones so widely separated from 

 each other, should belong to the same formation. But we have founded our opinion 

 upon their persistence when followed out upon their strike, upon their changes 

 of structure in places where there is no doubt of their continuity, upon their re- 

 lations to the overlying and underlying strata, and above all, upon their organic 

 remains, of which the most peculiar and characteristic are found throughout the 

 several ranges above indicated. 



No lithological description of the limestone, drawn from one neighbourhood, admits of general applica- 



* It will be seen, by consulting the map, that this limestone, at its eastern end, occupies two zones. 

 The northern zone extends from the neighbourhood of WUlfrath to Mettmann ; and to the west of the 

 latter place it is continued by a great flexure (characteristic of the enormous dislocations of the strata 

 in the north of Germany) into the southern range that extends to Elberfeldt, &c. 



