Devon and Cormjoall, Belgium, the Eifel, Sfc. 401 



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 antecedent^to 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- 



