400 Geological Society. 



towards the south-east by older formations, afterwards to be de- 

 scribed, and towards the south-west by an irregular line, skirting 

 the low country near the Rhin§, and passing near Mulheim, Ketwick, 

 Werder, and thence to a point a few miles north-east of Elberfeldt. 

 In its lithological character and fossil contents it is not to be di- 

 stinguished from tiie coal-fields of England. It is affected by many 

 anticlinal and synclinal lines, which have brought a lower and un- 

 productive portion to the surface, and thrown the productive por- 

 tions into a number of irregular troughs, ranging in the direction of 

 the strike, east-north-east. 



The lower and vinproductive coal-field is composed in part of 

 coarse grits, well exposed on the banks of the Ruhr, between Her- 

 decke and Schwerte, and of yellowish and light-coloured sandstones 

 and grits, with thin seams of coal and impressions of plants ; and the 

 strata are underlaid by dark gray micaceous slates and thin-bedded 

 hard sandstones, of great thickness, marked by many obscure impres- 

 sions of small plants. The lowest member of this series contains much 

 dark pyritous shale (Alauu Schiefer of the Germans), and reposes on 

 the upper calcareous zone of Westphalia (mountain limestone). 

 Several sections are described which confirm tiiis order of su- 

 perposition. The autiiors then state that this lower division of the 

 coal-field is greatly expanded towards the north-east; that it is litho- 

 logically almost identical with tlie great culm-field of Devon, and 

 resemble it also in its numerous impressions of small plants. It is 

 the Flotzlehrer Sandstein of the German geologists, and had been 

 regarded by them as the highest member of the graywacke series ; 

 but in the recently published map of Von Dechen, it is placed on 

 the parallel of the millstone grit of England. 



§ 2. Carboniferous limestone of Westphalia (Berg-Kalli), Kiesel 

 Schiefer, and bituminous limestone, S)-c. — The authors next describe the 

 limestone which commences at Cromford, near Ratingen, and I'anges 

 east-north-east to Velbert. Thence deflecting to the valley of Re- 

 grath, north of Tonnesheide, it is cut olF, and does not form a con- 

 tinuous band (as represented in all the German maps), with a lower 

 limestone, which commences a few miles further south, and ranges 

 through Metman to Elberfeldt. Near Cromford the limestone is 

 thick-bedded, and in its structure and fossils resembles the great 

 scar-limestone of England. For proofs the authors give several de- 

 tailed sections, and quote published lists of fossils. In its range to 

 the east it becomes more cherty, and abounds in casts of the stems 

 of Encrinites, so as to resemble the screw-stones of Derbyshire. At 

 several places (e. g. Isenbugel, Velbert, &c.) the connexion of the 

 limestone with the upper series is well exposed. The upper beds of 

 limestone pass into dark flat-bedded flinty slate, which is overlaid by 

 psammite and shale, with thin courses of flinty slate, and these dip 

 under the lower members of the coal-field. Again, there is at Vel- 

 bert a clear proof that the limestones, screw-stones, and flinty slate, 

 dip under the alum-slates of the neighbourhood. 



Following the strike of the county still further to the east, tlie 

 limestone range loses its mineral character; but a large group of 



