ETHEKIDGE DEVONIAN EOCKS AND FOSSILS. G13 



they are recognized as largely developed (both physically and 

 palseontologically) and are well understood by the Ehcnish, Belgian, 

 and Prench geologists. I also propose to examine the pala^ontological 

 relations between the Devonian and Carboniferous systems of Korth 

 Devon in particular, where their relations to each other are clearly 

 made out, and their succession and superposition complete. Again, 

 I propose to examine them in relation to the Carboniferous gene- 

 rally, more especially to that part of the group called the Car- 

 boniferous Slates, Coomhola Grits, or Lower Limestone Shales of 

 Ireland, to which Professor Jukes has assigned all the well-known 

 and peculiar Devonian species, as well as the rocks of Devonshire. 



The question as to which of the two conformable groups of rocks, 

 viz. the Old Ked Sandstone below, or the Carboniferous above, we 

 are to assign the Devonian series, is one, it is to be admitted, of some 

 difficulty ; but if we find an assemblage of organic remains having a 

 distinguished and peculiar fauna, characterized by species which are 

 peculiar to it, and totally distinct from the Silurian below, and largely 

 so from the Carboniferous above, as is the case with the Devonian 

 species, then, other things being equal, there are grounds for assign- 

 ing to the marine fossiliferous groujD of rocks under consideration an 

 intermediate position, be their relation to the two what it may. 



I take the whole of the Devonian series to be chronologically equi- 

 valent to the whole of the Old Eed Sandstone, or synchronously depo- 

 sited with that group, but under different mineral and life condi- 

 tions, and in a different geograjpliical area, not side by side, through 

 its whole or entire series, or synchronous with the Carboniferous, as 

 suggested by Prof. Jukes, the assemblage of organic remains no- 

 where justifying this proposition. Either we must admit that the 

 Devonian series is a marine equivalent in time of the Old Eed Sand- 

 stone as a whole, or it must be a distinct life-system, occupying an 

 immense area, spreading over an enormous interval of time between 

 the completion of the Old Ked Sandstone as a whole, and the 

 commencement of the succeeding and well-marked Carboniferous 

 series, and represented by contemporaneous deposits over a definite 

 and comparatively small area, in Europe (Eussia, Germany, Belgium, 

 and France), that area being governed or marked out, especially in 

 England, by geographical and physical conditions now difficult to 

 trace, owing to subsequent movements and denudation or through 

 the accumulation of newer strata along and over the south and west 

 of England. During this epoch, almost identical conditions seem to 

 have existed over the European area where the sandstones, slates, 

 and associated limestones were deposited, the rocks having peculiar 

 and marked physical resemblance, as well as possessing an almost 

 specifically identical fauna, notably so in the Ehenish provinces, 

 from the Taunus to Diisseldorf, the Belgian area, and the Bas 

 Boulonnais, in the North of France, — the stratigraphical position 

 and the zoological grouping of the Devonian rocks being of marked 

 similarity every^-here. 



^Whatever precise relation the three divisions of the Devonian may 

 have in time to the three equally well-marked groupings of the 



