482 
omitting the Killas and other slate-rocks of the Devonian system, 
which have now been shown to appertain to it. 
I further stated, that it would probably be found that this Devo- 
~ nian system includes a large amount of strata upon the continent of 
Europe, which had been hitherto known by the Wernerian name 
Grauwacke ; and expressed my satisfaction that this name was likely 
to retain its place in the nomenclature of geology, as a generic term 
co-extensive with the transition series of the school of Freyberg, and 
divisible into three great subordinate formations, namely, the De- 
vonian, Silurian, and Cambrian systems. 
The labours of Professor Sedgwick and Mr. Murchison in the 
Rhenish provinces and adjacent parts of Germany, in the summer of 
1839, have furnished important additions to our knowledge of the 
older rocks of the continent, and brought them into comparison with 
the recently established paleozoic types of England; the first efforts 
of those authors were directed to the right bank of the Rhine, 
where taking the coal-field of Westphalia as a fixed horizon, they 
proceeded to deduce therefrom the descending order of the older 
formations which emerge southwards from beneath that deposit, and 
established a perfect sequence along a frontier of fifty miles in 
length, from a true coal-field with carboniferous limestone down- 
wards into Silurian rocks, by passing through an intermediate group 
loaded with Devonian fossils*. ; 
In following out these strata to the E.N.E. the authors were 
astonished at the vast flexures, first laid down by Von Buch and 
Hoffman, and since more elaborately made out by Von Dechen and 
Erbreich; and perceived that the shales become more crystalline and 
slaty, and charged with mineral veins, and the limestones assume 
* This order was not made clear until some startling difficulties were 
overcome. All the German authorities had laid down as one continu- 
ous: band (defining the same as berg-kalk), the limestone which at Ra- 
tingen is undoubtedly true mountain-limestone, and the calcareous zone 
which passes from W.S.W. to E.N.E. by the towns of Elberfeldt and 
Iserlohn. Now although at a first glance the physical features of the 
country seemed to favour this view (which was indeed adopted in the new 
map of Von Dechen), the close examination of the authors detected, that 
whilst the Ratingen limestone contained the fossils of the carboniferous 
system, that of Elberfeldt and Iserlohn was charged with different types, 
most of which exist in the lower limestone of Devonshire. Having assured 
themselves, therefore, that there was an error in the works of previous 
observers, they returned to Ratingen, and following the carboniferous 
limestone eastward along its strike they found it to be separated from 
that of Elberfeldt, gradually changing in its structure, and passing into 
thin-bedded black limestone associated with much flinty schist (kiesel 
schiefer) and chert, and assuming the lithological characters and fossils of 
the black or culm-limestone of Devonshire. 
This black limestone is overlaid by unproductive measures of the coal 
series, similar to the upper strata of the great trough of North Devon, and 
is underlaid by psammites, schists, and limestone (Elberfeldt and Iser- 
lohn) containing Devonian fossils, and reposing upon schistose and grau- 
wacke rocks which contain Silurian‘ fossils. 
