484 
limestones next below the coal-field and carboniterous limestone of 
Liége are the exact equivalents of the series which in Westphalia 
represent the Devonian system. The fossils are the same as those 
of Elberfeldt, Paffrath, and Devonshire. These beds also contain 
fishes of the genus Holoptychius, which Agassiz has identified with 
types of the old red sandstone; and on all these grounds, as well as 
by complete lithological and stratigraphical passage into the over- 
lying carboniferous group, our authors establish that the terrain 
anthraxifére of D’Omalius and Dumont is, like the schistose rocks — 
of Devonshire, the true equivalent of the old red sandstone. 
~The mountains of the Ardennes consist in their upper members of 
equivalents of the Silurian system, as indicated both by order of in- 
fraposition to the Devonian rocks, and by containing the same types 
of fossils which characterize the Silurian strata on the right bank of 
the Rhine; whilst the oldest slaty rocks, in which no fossils have 
been discovered, are presumed to be in the parallel of the. Upper 
Cambrian group. 
The limestones of the Eifel, well known by their fossils, lie in 
a basin supported by Silurian rocks, and are identical with the 
lower Devonian limestones of Liége, Westphalia, and Nassau ; 
whilst the shales beneath them graduate into Silurian grauwacke, 
and contain so many Silurian species that (together with the well- 
known schists of Wissenbach on the right bank of the Rhine) they 
are considered to form the uppermost members of the Silurian di- 
vision. 
A similar succession to that from the Eifel to the Ardennes is. 
observable between the Fifel and the Hundsruck, the upper Silurian 
flagstones being highly fossiliferous, but much contorted and dis- 
turbed and altered in their mineral condition ; the banks of the 
Moselle offer the finest proofs of such disturbances. The fossils 
found in the quartzose rocks of the Hundsruck prove this mountain 
chain, which is a prolongation of the Taunus, to be, like it, of Silu- 
rian formation. 
In the Hartz, the authors traced the same succession of mineral 
masses, each characterized by their peculiar fossils; and, if possible, 
in still more dislocated positions. In one section, however, they 
point out a tolerably regular descending order, from the mining 
tracts of Clausthal, where the beds are the equivalents of the car- 
boniferous strata (floetzlehrer sandstein of the Germans) down to 
limestones charged with Devonian types; but in other parts, as 
near Goslar, the still older Silurian’ rocks occur upon the flanks of 
the Brocken, and overlie the Devonian schists ; whilst it is shown 
that the granite of the Brocken was in a molten condition after the 
formation of these old rocks, fragments of which full of shells are 
found included in this Granite. Other sections show that the chain 
has subsequently been heaved up “en masse,” and all the secondary 
strata on its northern flanks set on edge, and in some instances in- 
verted, from the Muschelkalk and New red sandstone to the Green- 
sand inclusive. The authors believe that the last great dislocations 
of the Hartz may be due (as suggested by Von Buch) to the erup- 
