Chap, XVI.] CAKBONIFEKOUS KOCKS OF BELGIUM ETC. 
401 
Carboniferous Rocks of the Rhenish Provinces and Belgium. — The upward suc- 
cession from the Devonian into the Carboniferous deposits is clear on both banks 
of the Rhine and in Belgium ; and if in the latter country certain Lower Carbo- 
niferous schists are attenuated, this thinning-out of one portion is more than 
compensated by the presence of noble masses of Carboniferous Limestone. 
The Carboniferous Limestone of Belgium reposes, however, upon the Devo- 
nian schists containing Spirifer disjunctus (or Verneuilii), the well-known fossil 
of the Rhenish-Prussian tracts and the Boulonnais, without any trace of those 
lower sandstones which are so largely intercalated in Scotland and Ireland 
(pp. 291 and 294). This Carboniferous Limestone, and a thin overlying sandstone 
representing the Millstone-grit, form the support of the two great Coal-basins of 
Liege and Hainault. The numerous repetitions and folds of this rock, as dis- 
tinguished from the lower or Devonian limestone, are admirably displayed in 
M. Dumont's map and sections. 
During his earlier researches, M. de Koninck was led to believe in the exist- 
ence of two distinct zones of Carboniferous Limestone, as expressed in the first 
edition of this work (p. 375), the fossils of the tract near Vise being very differ- 
ent from those of Tournay. He now, however, has come to the conclusion 
that both these form one natural mass, since, although their respective fossils 
differ materially, they are closely united by a number of species common to both 
districts. Illustrating and extending the application of his views, M. de Koninck 
further suggests that the fossil species of Vise and Tournay are repeated in like 
manner in several localities of the British Isles respectively ; and he traces the 
same distinction over the Continent to the Ural Mountains on the east, and 
across the Atlantic to America on the west. 
In making these extensive comparisons, M. de Koninck enumerates 53 species 
as distinctive of the Vise assemblage, and 57 species as characteristic of Tour- 
nay ; whilst he cites 40 species which are common to both localities. The 
latter, or the common forms, belong chiefly to the genera Euomphalus, Pleuro- 
tomaria, Bellerophon, Productus, Orthis, Athyris, Rhynchonella, with the Tri- 
lobite Phillipsia, and palates of Psammodus and other Fishes. 
Through the comparisons instituted by this able palaeontologist, we learn that 
many of the same species were so widely spread out during the Carboniferous 
era as to extend over the northern hemisphere, being here and there collocated 
in distinctive assemblages, often at great distances from each other, — those parts 
of the ocean having been specially suitable to their existence. 
The splendid rocks of this formation, which the traveller admires as he passes 
along the railroad from Namur to Liege, gradually thin out as they range 
towards the Rhine. They make, in short, their last appearance as a solid lime- 
stone at Cromford near Ratingen, on the right bank of the Rhine ; for in ex- 
tending thence to the east and north they become almost non-calcareous. 
Instead of two or more massive divisions, they dwindle into one or two thin, flat 
beds of black limestone, very similar to the black Culm-stone of Devonshire, 
which is in that district the feeble representative of the great Carboniferous or 
Mountain Limestone of other parts of England. Like the Devonshire rocks, the 
Westphalian strata are characterized by the Posidonomya Becheri, which occurs 
in Belgium, even where the calcareous matter is entirely absent, as well as in 
the schists of Herborn and other places, distinctly marking the centre of the 
Lower Carboniferous rocks. 
In the Rhenish Provinces the lower member (the schists below the lime- 
stone) is usually very siliceous, and is in that tract the ' Kiesel-Schiefer ' of the 
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