Vol. 63.^ BASEMENT-BEDS OF THE BRISTOL COALFIELD. 463 



which are wide, concave near their outer border (perhaps as a 

 result of pressure), and rise into a gentle convexity as the suture- 

 line is approached. The tuberculations form the summit of the 

 convexity, from which the shell-wall slopes downwards to join the 

 suture-line. Diameter = 12 millimetres ; height = 5 mm. 



The species is easily distinguishable by the acute spire rising from 

 the middle of the last two broad and flat whorls. Inasmuch as the 

 genus Jiaphistoma has hitherto only included flattened forms destitute 

 of any spire, this species will probably have to be removed from that 

 genus, but there is no existing genus to which we have been able 

 to refer it. 



Pleurotomaria carinata (Sowerby). 



Spire acute, of five whorls, median band broad, concave. Surface 

 exhibiting curved striae, the convexity directed forwards. All the 

 available examples of this species are crushed. 



Pleurotomaria gemmulifera, Phillips. (PI. XXX, figs. 14a & 146.) 



A somewhat bluntly-conical shell, convex above the median band, 

 and ornamented by five longitudinal rows of minute tubercles. 

 Median band broad and slightly concave. Whorls five. Height = 

 4 millimetres ; width = 5 mm. 



Eophemtjs TJrei, Fleming. 



Several examples of this species were obtained. Although much 

 crushed, sufficient of the characteristic surface- ornament was 

 preserved to determine the species. 



Eellerophon hiulcus, Martin. 



A few fine examples of this species were met with. Unlike the 

 previous species, the shells are well preserved, and show the surface- 

 ornament admirably. 



Belleropbion bicarenus, Leveille. 



Only a single fragment of a shell of this species was found, but 

 fortunately showing the wide concave dorsal sulcus, with slightly- 

 raised margins. The surface-features agree very well with 

 L. de Koninck's description of his first variety. 1 



Macrocheiltts cf. ventricostjs, de Koninck. (PI. XXX, fig. 15.) 



A single specimen, the surface of which is obscured by a shaly 

 covering, which cannot be removed. The spire is short, acute, of 

 six to seven whorls, the first very small, and the last extremely 

 deep and broad. The mouth-aperture is broken, but apparently oval. 

 In the low acute spire, rapidly-enlarging whorls, and large body- 

 chamber, this example agrees with the genus Macrocheilus, while 

 the mouth-aperture possesses a ventral reflection similar to that 

 seen in M. ventrieosiis. 



1 ' Description des Animaux Fossiles ' 1842-14, p. 353. 

 Q. J. G. S. No. 252. 2 l 



