4U 



THE GEOLOGIST. 



its external form it is not unlike Terebratulina suhradiata, but it does 

 not, in any example I liave seen, attain one-tenth tlie size of 

 that species. It is also more circular, less convex, and has a more 

 pronounced sinus in the ventral valve than that shell.* 



The T. racliata appears to have continued upwards from the Inferior 

 Oolite, as I am unable to separate from it some specimens I have 

 obtained from Dundry, near Bristol, the only distinction being that 

 the latter assume a more elongated form, which is to be observed by 

 comparing pi. xiii., fig. 14 (from Dundry) with figs. 11, 12 (from 

 Hampton Cliffs). 



Zellania. Moore: 1854. 



Three species of this genus were described by me in the Transactions 

 of the Somersetshire Natural History Society, for 1854 ; one being 

 from the Upper Lias, the other from the Inferior Oolite of Dundry. 

 To these I have to add another from Dundry, and a fifth species from 

 the Oolite of Hampton Cliffs. The genus also occurs in the Coral 

 Rag of Lyneham, Wilts. Its range is therefore shown to extend 

 from the Upper Lias to the uppermost beds of the Oolite. 



Zellania globata. Moore. PI. xiii., figs. 15-17. 



Shell very small, globose ; valves moderately convex, rounded at 

 sides and front ; exterior surface smooth ; beak slightly projecting ; 

 foramen encroaching on both valves, rounded, 



Ohs. — I have five examples of this shell from the Oolite of Hamp- 

 ton. The interior of the dorsal valve possesses a well defined circular 

 ridge, entirely encircling the inner portion of the shell. In this 

 species I have been unable to observe any trace of a central septum, 

 which in those previously figured is well defined. The examples 

 that occur in the Coral Rag, at Lyneham, are of the same species, 

 and are equally rare. 



Zellania oolitica. Moore. PI. xiii., figs. 18-20. 



Shell small, triangular, rather longer than -wide ; front rounded ; 

 valves tapering to the beak, smooth, distinctly puntuate, thickest at 

 the umbo ; sides thick, flattened ; hinge-line very short ; foramen 

 rounded. 



This species is found ^vith the Z. Vavidsoni and Z. Lahouclicrci. 

 It is a thicker and more triangular shell than the former, and is de- 

 void of the stride noticed on that shell. In 'its triangular and less 

 symmetrical form it is to be distinguished from Z. Lahouclierei ; and 

 it also wants the concentric lines on the valves characteristic of that 

 species. The shell structure of the genus is shown by the Z. oolitica 

 to be distinctly punctuate. 



* In all the examples that have come under my notice, the crm-al processes, 

 which arc usually joined in this genus, are discomiected. 



