Mr. F. Forster's Observations on the South Welsh Coal Basin, 85 



seams impracticable. It is not, indeed, uncommon to find miners 

 among the Welsh collieries, generally speaking a very intelligent race 

 of men, who have not yet become converts to Mr. Martin's idea of a 

 mineral Basin : to the same cause may probably be attributed the term 

 gwythyen, or vein^ universally given by the Welsh miners to a seam or 

 bed of Coal. 



To the late Mr. Martin's valuable paper we are, I believe, indebted 

 for the first idea of a Coal Basin, or trough of Coal Measures, reposing 

 upon a distinct, continuous, and underlying mass of carboniferous Lime- 

 stone ; a formation which, however indefinite in the Northumberland 

 and Durham Coal districts, is most clearly developed in the South 

 Welsh Coal-field. Of the boundaries of this Basin, Mr. Martin has 

 also given a sketch, together with a perpendicular section, apparently 

 taken in the vicinity of Merthyr ; these are accompanied by a variety of 

 observations reflecting the highest credit upon the ingenuity and re- 

 search of the author, and such, in fact, as might have been expected 

 from a mineral surveyor of such extensive practice and high character. 



Mr. De la Beche, in the 2d. vol. of the Geological Transactions, 2d. 

 series, has published a highly interesting account of the geology of 

 Southern Pembrokeshire, accompanied by a map and sections, in which 

 he includes that part of the great Coal Basin extending across the 

 county of Pembroke. As the apparent object of this paper is to point 

 out the geological relations of the different rocks ranging through the 

 district, composed of Trap, Greywacke, Old Red Sandstone, carbonife- 

 rous Limestone, and the Coal Measures, the author necessarily makes 

 the quality, &c. of the Coal beds themselves, a matter of subordinate 

 consideration. The effects produced by the Trap rocks, occasionally 

 interposed between the different members of this part of the Coal-field, 

 as described by Mr. De la Beche, bear a striking resemblance to 

 the undulations and contortions of the strata, along the N. E. coast of 

 Northumberland, and which may probably be attributed to the same 

 disturbing cause. 



Messrs. BucKLAND and Conybeare, in the paper already quoted, 

 have illustrated in a most lucid manner, the Coal Basins of Bristol 



