MOOKE — ON NEW BRACHIOPODA, ETC. 



430 



At the time referred to but fourteen species, of the genera Lin- 

 gula, Orbicula, Spirifer, and Terebratula had been figured from 

 the three divisions of the Lias, but I had succeeded in discovering 

 twenty new species in the Middle and Upper Lias of Somerset, in- 

 cluding the genera Thecideum, Leptsena, and Crania, genera which 

 had been previously unnoticed in these formations. 



Of the genus Thecideum, the Middle Lias of Somerset yielded me 

 three species, viz.. T. JBoucJiardu, T. triangularis, T. Moorei. In this 

 formation they are rare, and when found are almost invariably 

 attached to the plicated exteriors of EJiyncJwnella serrata or B. tetrae- 

 dra. On a specimen of the former shell, which has been figured by 

 Mr. Davidson, there are seventeen examples belonging to the three 

 species I have mentioned. 



The Upper Lias of the west of England, especially in the neigh- 

 bourhood of Ilminster, rarely exceeds in thickness ten or twelve feet, 

 and is sometimes reduced to four or five feet. In the clays afc its 

 base the genus Leptsena occm-s of several species. About the time 

 of their discovery, one species, the Leptcena liasiana, had been found 

 in France, which I had sought for in vain in this country. During a 

 visit paid me by Mr. Davidson, as we w^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 delight the first object that presented itself to me was a 

 little 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 Bracliiopoda, and 

 found there eight species of Thecideum, five of which w^ere new, 

 together with the T. Boucliardii and T. triangidaris I had previously 

 obtained from the Middle Lias,, and T. DeslongcliaAnrpsii of the Upper 

 Lias. The same locality also furnished me Avith a series of little 

 shells, which threw light upon some I had previously found in the 

 Upper Lias, forming a passage between the Thecideid^ and the 

 Terebratulidae, for which the sub-genus Zellania has been created. 

 These, with a little shell named Spirifer a oolitica, were shortly 

 noticed by me in Mr. Davidson's " Appendix," but have since been 

 figured and described in the Journal of the Somersetshire JSTatural 

 History Society for 1854. At the time of its publication I was con- 

 vinced that the discovery of many new species of Brachiopoda might 

 be expected from a continued investigation of the secondary forma- 

 tions ; and it is to new species found since I now desire to direct 

 attention. 



On Hampton Down, near Baih, there are extensive excavations 

 where the Great Oolite was formerly largely worked. Latterly a 

 new quarry has been commenced, and in order to reach the workable 

 beds of freestone, the following beds in descending order had to be 

 passed through : — ■ 



