156 PAPERS, ETC. 



exterlors of Rhynchonella serrata or R. tetraedra. On a 

 speclmen of the former shell, whicli has been figured by 

 Mr. Davidson, tliere are seventcen examples belonging to 

 the three species I liave mentioned. 



The Upper Llas of the west of England, especially in 

 the neighbourhood of Ihninster, rarely exceeds in thickness 

 teil or twelve feet, and is sometimes reduced to four or five 

 feet. In the clays at its base the genus Lejjtajna occurs 

 of several species. About the tlme of their discovery, one 

 species, the Leptaina liasiana, had been found in France, 

 which I had sought for in vain in this country. Duiüng a 

 visit paid me by Mr. Davidson, as we vi^ere approaching a 

 section of Upper Lias, he remarked how interesting it 

 would be to find the French species in association with 

 those I had already discovered. To our great dehght the 

 first object that presented itself to me was a llttle shell, 

 which rendered the L. liasiana a British species. I have 

 never found more than four specimens, so that it is very 

 rare. 



Before the publication of Mr. Davidson's "Appendix," 

 in 1853, I had examined the Inferior Oolite of Dundry for 

 Brachiopoda, and found there eight species of Thecldeum, 

 five of Avhich were new, together with the T. Eouchardii 

 and T. triangularis I had previously obtained from the 

 Middle Lias, and T. Dcslongchampsii of the Upper Lias. 

 The same locality also furnished nie with a series of llttle 

 Shells, which threw light upon sonie I had previously 

 found in the Upper Lias, forming a passage between the 

 Thecldeidaj and the Terebratulidaj, for which the sub- 

 genus Zellania has been created. These, with a little 

 shell named Spirifera oolitica, were shortly noticed by me 

 in Mr. Davidson's "Appendix," and were, in 1854, figured 

 in the Proceedings of the Somersets hij-e Archoeological and 



