NORTHUMBERLAND AND DURHAM. 273 



some of these will follow in tlie next paper, it is only necessary 

 to refer to it for a wcll-cliaracteriscd description of tlic species. 

 Found in the shell-limestone, Tunstall Hill. 



29. CALYPTRiEA, Lam. 



1. C. AXTiQUA, Ilowse. PI. XI. figs. IG, 17. 



In 1847 I found a single imperfect specimen of a patelliform 

 shell at Tunstall Hill, which was described thus in the '' Tyne- 

 side Catalogue:" — 



" Shell small, patelliform, strongly ribbed longitudinally ; margin 

 crenulated ; two deep farrows internally from the apex to the margin, 

 corresjjotiding ivith two strong ribs on the outer surfaced 



The only specimen found was not quite perfect round the 

 margin, and the whole shell had the appearance of being irregu- 

 larly grown. It was thought, however, desirable to include it 

 in the Permian list, and to affix an epithet to it, for the sake of 

 reference. Mr. King, not being acquainted with it, and conse- 

 quently considering it a " doubtful species," placed it in the 

 Appendix to the " Permian Monograph" (p. 247). Mr. Kirkby 

 has, how^ever, lately with his usual success detected three more 

 specimens, two of which were found in the same part of the 

 quarry in which the original specimen Avas discovered. Mr. 

 King may also assure himself that it is not a " doubtful species,'' 

 by examining the type-specimen in the Museum of the Geologi- 

 cal Survey, Jermyn Street, London. In the first draught of this 

 paper, I too hastily identified the Patella Hollebeni, Schauroth, 

 with this species, but since that time I have examined a clay- 

 cast of that supposed species, and I think that it represents 

 only a distorted or compressed Dis'cina. 



The only known examples are. . from the shell-limestone, 

 Tunstall Hill. 



30. EULIMA, Risso. 



1. E. SYMMETRICA, King. 



In the " diagnosis" given by Mr. King, the general form of 

 this shell is incorrectly stated to be ^'■fusiform.'''' There is no 

 fusiform shell in flie Permian system that I am acquainted with, 



