401 
Devon and Corivwall^ Belgium^ the Eifel^ %c. 
This view leads naturally to the inference, that in the order 
of superposition the Eifel limestone occupies a middle rank, 
namely, one higher in the series than the Wenlock, but lower 
than the carboniferous limestone. This result would appear 
to correspond with the notions of M. Beyrich, who, in spe- 
culating on the relative age which should be assigned to the 
Rhenish slate mountains among the transition formations, is 
disposed to consider them as of a later origin than those strata 
in the north of Europe, namely in Scandinavia and Russia, 
in which the Orthis tribe are so abundant. These latter may 
doubtless be placed, to a certain extent, in parallel with the 
Silurian. 
If the views which I have taken be correct, in which the 
formations of the Eifel, and the lower formations in Belgium 
are, in the order of succession, considered as antecedentfto the 
old red sandstone of Belgium (meaning such as in Britain 
has been usually designated by that name), it becomes doubly 
desirable that the distinguished geologists who have taken 
Devon and Cornwall in hand should complete their investi- 
gations. I have been led to anticipate that a considerable 
degree of analogy subsists between the two regions, and, if 
it be true, it may yet be proved that the older stratified rocks 
of those counties are not only of later origin than the Silu- 
rian formations (which would so far correspond with the views 
of Mr. Lonsdale, Professor Sedgwick, and Mr. Murchison), 
but of a date also anterior to that of the old red sandstone 
formation, taken in the common acceptation of that term. 
Whether the latter may yet be detected in the southern parts 
of Devon in unconformed position, may still be a fit subject 
for inquiry. 
It is remarkable that among the fossils by which the Devon- 
shire and Cornish formations are distinguished, Mr. Austen 
should state a number to exist as common to the carbonife- 
rous limestone, so nearly agreeing with the number of a cor- 
responding character in the Eifel, namely, as 40 and 47. An 
account of the 40 species indicated by Mr. Austen, it is to be 
hoped, may be published, and it will be interesting to com- 
pare them with the list that I have given from the Eifel. 
What ratio that number may bear to the total number of 
species in the older stratified rocks of Devon and Cornwall 
remains yet to be seen, as well as what number of species may 
be common to the Silurian, what number may be similar to 
the Eifel fossils, or to those of the older stratified rocks and 
their included limestone bands in the south of Ireland, and 
what number may be more peculiarly distinctive of Devon 
and Cornwall. These are questions which can only be an- 
