42 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. ['NoY. 9, 



At all the localities it has been found in the White Limestone (Upper 

 Chalk). 



17. Teeebbatttla (Waldheimia) Hibernica, spec. nov. PL Y. 



figs. 3 a-3 c. 



Shell somewhat longitudinally ovate, or orbicular, slightly de- 

 pressed ; surface marked by numerous faint concentric striae ; shell- 

 structure largely punctated. Yalves nearly equally convex. Margin 

 subobtuse, flexuous ; the imj)erforated valve with a very shallow 

 longitudinal depression and a tendency to bifurcation. Beak in- 

 curved and obliquely truncated by an elliptical foramen, surrounded 

 and separated from the hinge-line by a deltidium of two pieces. 

 Beak-ridges moderately incurved, rather obtuse. 



Dimensions. — Length -| inch ; breadth ^-^ ; depth ^. 



Affinities and Differences. — It is most nearly allied to W. tama- 

 riyidus, Sow., from which it differs in its more oblong form, bifur- 

 cation of the upper valve, smaller foramen, greater development of 

 the deltidium-plates, and more obtuse beak-ridges, and in the pre- 

 sence of numerous fine concentric striae. It is also a smaller species, 

 and never becomes obovate like many specimens of W, tamarindus. 

 Sow. W. Celtica is at once distinguished from W. Hihernica by its 

 remarkably elongated form. 



At present I am unacquainted with the character of the loop ; 

 but the general form of the shell warrants me in referring it to the 

 above subgenus. 



Loccdity. — It is common in a compact chloritic sandstone in Colin 

 Glen, of the Zone of Exogyra columba of the Hibernian Greensand. 



18. Terebeatitlina Deprancei, Brong. PL lY. fig. 4. 



The fragment of this conspicuous species, or adult variety, as it 

 may be, of T. striata, Wahl., is the first indication of the occurrence 

 of this form in the British Isles. Being a new and interesting ad- 

 dition to British palaeontology, it is here figured. 



The figured fragment is the only one known; it was obtained 

 by me from the flinty flag (Upper Chalk), at Kilcorig, Lisburn. 



19. Rhynchonella limbata, Schloth., var. robusta, var. nov. PL Y, 



figs. 2 a-2 c. 

 This well-marked variety of i?. limbata is very distinct on ac- 

 count of the exceeding gibbosity of the shell ; it is moreover of larger 

 dimensions than specimens of JR. limbata usually are. It is exceed- 

 ingly common in the Zone oi Inocer-amus Cnspi, atWoodburn, White- 

 head, and Island Magee. It is not found in any other zone. 



Etheridgia, gen. nov. 

 Characters. — Conoid, summit truncated and pierced by a relatively 

 large opening communicating with the interior. Base rather fiat, 

 provided with radiciform processes of attachment, disposed infra- 

 marginally and centrally. The external surface of the cone is pro- 

 vided with larger circular oscules, with an irregular biserial arrange- 

 ment, between which are minute pores. 



