8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [NoV. 5, 



found all the species of Cucullcjea, so-called, and the specimens are 

 there quite as abundant as at Marwood. It is the Bolabra of M*Coy ; 

 and several of the species are found in the "■ yellow sandstone " of 

 Ireland. Mineralogically indeed, as well as zoologically, the Baggy 

 Point sandstone agrees very closely with the Irish "yellow sandstone." 

 Along with the Bolabrce was a new species of Leptodomus^ L. sulca- 

 tus, M'Coy. Under the Bolabrce of Marwood we found several 

 specimens of the Aspidaria of Romer, a true Carboniferous fossil ; 

 and it would appear from the statements of the late Mr. Williams, 

 that Vegetable fossils are not rare in the Marwood Group. 



It would be idle to detain the reader, in such an outline as this, 

 with any account of the fine examples of an oblique slaty cleavage in 

 Croyde Bay, of the calcareous concretions, and ofthe numerous fossils 

 between Marwood and Barnstaple. Copious lists may be selected from 

 Phillips*. 



Mr. Griffith's original statement of the very near agreement of the 

 Carboniferous slate of Ireland with the groups just noticed is com- 

 pletely confirmed by what we saw this summer ; and that the " car- 

 boniferous slate " is an integral portion of the Carboniferous series of 

 Ireland appears now to admit of no doubt. 



The black shales, which underlie the culm-limestone on both sides 

 of the great culm-trough of Devon, are of great thickness, sometimes 

 contain (as we learnt from the collection of Mr. Pattison) the com- 

 mon Posidonia of the culm-limestone, and form an excellent and well- 

 defined physical base to the whole culm-series. But below them 

 there is, in the Petherwin and Barnstaple Groups, a very great phy- 

 sical as well as palseontological change. Physically at least, the 

 Petherwin Group is far more nearly connected with the Devonian, 

 than with the Carboniferous groups. On the contrary, it appears to 

 admit of no doubt that the Petherwin and Barnstaple Groups are 

 zoologically more nearly connected with the Carboniferous than with 

 the Devonian groups. Prof. Phillips f states that Mr. Gilbertson 

 had obtained a specimen of Clymenia from the Mountain-limestone 

 of Ireland ; but it deserves remark, that, considerably before the time 

 alluded to. Count Miinster had obtained a Clymenia from the Car- 

 boniferous rocks of Ireland. So far as this evidence goes, it seems 

 to prove that the Petherwin Group ought rather to be clasSed with 

 the Culmiferous series than with the Devonian. On the other 

 hand, several of the facts stated by Count Miinster seem to prove 

 that the Clymenia-groups of the Fichtelgebirge are Devonian rather 

 than Carboniferous. While this kind of evidence is in conflict, I 

 would retain the good physical base-line of the culm-series, nearly as 

 it was laid down by Sir R. I. Murchison and myself; and in doing 

 this I have the entire concurrence of Prof. M'Coy. Were I, how- 

 ever, to colour geologically the maps of Devonshire and Cornwall, I 

 should give an intermediate tint to the groups here noticed, in order 

 to mark their true place in the series, and their very near connexion 

 with the overlying Carboniferous groups. 



So far I have been reviewing a series of facts that have often been 

 * Op. cit. t Palaeozoic Fossils, p. 124. 



