191 



On the position of Gryphcea mcurva in the Lower Lias at Bridgend. 



To THE Hon. Secretauy op the Cotteswold Naturalists' Field 

 Club : 



My dear Sir, 



I feel it due to the Club, and to myself, to bring before it the result 

 of some coiTespondence between myself and Mr. Charles Moore, 

 of Bath, in reference to the vertical distribution of Gryphcea incurva 

 in English Liassic beds. It will be seen at page 93 of the 

 letter-press of my commvmication upon that species, that upon the 

 authority of Mr. R. Tomes, of Welford, I figured in plate 1, figs. 55 

 and 56, a specimen which that gentleman sent to me from what 

 he considered to be the White Lias of Bridgend, in Glamorganshire. 

 As stated distinctly by me, I adopted the specimen and its alleged 

 stratigraphical position entirely upon Mr. Tomes's authority. Mr. 

 Moore, to whom I sent a copy of the publication, informed me that 

 I was entirely in error upon this point, as the beds at Bridgend were 

 well known to him ; that they consisted entirely of those which con- 

 stitute the Lima series, and that the White Lias was nowhere developed 

 in that neighbourhood. As the point in dispute lay entirely between 

 him and Mr. Tomes, I referred each to the other, and they agreed, with 

 a persistency in the cause of truth which we must all admire, to meet 

 and discuss their differences upon the gi'ound. 



Mr. Tomes said that the stratum in which he found the specimen in 

 question was White Lias, because the Ostrea interstriata, a characteristic 

 shell of Moore's own Rhcetic formation, was found abundantly vnth. it. 

 Mr. Moore, who had long known the beds in question, entirely dissented 

 from Mr. Tomes's views. By a letter dated June 30, 1863, I learn from 

 Mr. Moore that he met Mr. Tomes, accompanied by some friends, at 

 Bridgend, and the meeting has resulted in the following compromise as 

 imparted to me by Mr. MooRE. He says, " I am happy to say that we 

 " came to an unanimous conclusion on the points, viz. : — There are no 

 " beds at Bridgend lower than the Lirna series, and that the G. incurva 

 " therefore, which has been figured from thence, belongs to this zone, 

 " Further, Tomes was correct in saying that the Ostrea interstriata was 

 " associated with G. incu/rva, the former being a typical shell of the 

 " RliCBtic or White Lias beds, but we made out the interesting fact that 

 " the shell is a derived one, and has been washed out of lower beds, and 

 " re-deposited with the fauna of the Lima series. In general we foimd 

 " that the little oyster was attached to Carboniferous Limestone pebbles. 



