EXPLANATION OF THE PLATES AND WOODCUTS. 



the authors ; and the map is chiefly intended to indicate approximately the relations of 

 the great subdivisions of the older sedimentary deposits: p. 227 ^t seq. 



PLATES XXV. to XXXVIII. 



The description of these Plates of Fossils illustrative of the Devonian and Silurian strata of the 

 Rhenish provinces is given in the Memoir of Viscount d'Archiac and M. de Vemeuil, 

 and in the notice of their contents in a subsequent page of the explanation. 



WOODCUTS. 



Fig. 1. Section near Arnsberg in Westphalia. An axis of carboniferous black limestone and 

 Kiesel-schiefer, representatives of the culm limestone and flinty slate of Devonshire, is 

 shown to be succeeded on each flank by the lower unproductive coal-measures, undistin- 

 guishable from those of Bideford : p. 233. 



Fig. 2. Section of the general relations of the strata north and south of Brilon, exhibiting the 

 disturbances produced by the igneous rocks : p. 239. 



Fig. 3. This section presents the connexion of the limestone, iron-ore and schist, with por- 

 phyry, at Carpenheim, near Wetzlar, on the left bank of the Lahn : p. 250. 



Figs. 4 and 5. Sections of the schaalstein and associated strata near Miinchen-Miihle and Ar- 

 furth: p. 251. 



Fig. 6, Exhibits the manner in which the fossiliferous strata have been detached from the 

 original position by porphyry, near Bilstein : p. 264. 



Fig. 7- This section, from near the mouth of the Lahn, presents an instance of wedge-shaped 

 masses of sandstone associated with slates, the whole mass being dislocated and highly in- 

 clined: p. 265. 



Fig. 8. Section of the contorted and disturbed Silurian strata at Ehrenbreitstein : p. 265. 



Fig. 9. Section opposite Braideburg of contorted beds of arenaceous and slaty greywacke, 

 covered in part, obliquely, by another series of slaty beds of the same age : p. 266. 



Fig. 10 e, b. Diagrams to illustrate the nature of upright and inclined basins. Fig. 10«. exhi- 

 bits an upright basin, in which a line drawn from near the centre, through the point of 

 greatest curvature, falls within the area of the basin. Fig. 10b. is an inclined basin, in 

 which a similarly drawn line falls without the area of the basin : p. 268. 



Fig. 11. A species oi Homalonotus resembling H. Knightiix p. 275. 



Fig. 12. Section from Weingarten to Miinster Eifel, exhibiting a regular sequence at one ex- 

 tremity, and an apparent, but inverted, succession at the other : p. 277- 



Fig. 13. Section of the celebrated fossiliferous strata of Gerolstein, and of their dislocations. 

 The organic remains are, for the most part, procured from the bands of limestone and 

 shale between the dolomite and the Silurian flagstones with Homalonoti : p. 278. 



Figs. 14 and 15. Sections in the Hartz : p. 286. 



Fig. 14. Inverted and fragmentary condition of Devonian and Silurian strata near 

 Goslar, north of the Brocken : p. 286. 



Fig. 15. Section from the greywacke of Netzberg to the hunter sandstein of Nordhau- 

 sen, with interpolated masses of quarzfreier porphyr : p. 286. 



