550 R. F. Tomes — Some Cretaceous Madreforaria. 



to the bottom of the Eed Chalk, and Wiizangia elongata from the 

 middle part only.^ 



There is great reason for supposing that the genus Wiizangia 

 occurs in the Oolitic strata of Gloucestershire. I have seen two 

 corallites attached to a Tliamnastrcea from the Lower Trigonia grit 

 of Eavensgate Hill, Cheltenham, which are probably referable to 

 that genus ; and I have one from a bed of Oolitic gravel between 

 Cirencester and South Cerney. The latter is without doubt a 

 Bhizangia, and as it was associated with other Oolitic corals, it was 

 probably derived from some part of the Oolitic series. 



Ehizangia mamilliformis, Dune. sp. PI. XIV. Figs. 7, 8, and 9. 



Todoseris mammiliformis, Duncan. Supp. Brit. Foss. Cor. pt. ii. p. 25, pi. ix. figs. 



2-15, 1868. 

 The greater number of the specimens from Hunstanton consist of 

 isolated and worn corallites. A limited number show the base and 

 its ragged margin, while in three instances only have I seen the 

 corallites connected by the calcified stolon. Not unfrequently 

 specimens may be observed attached to Belemnites, over which the 

 thread-like extension of the stolon is seen. A short piece of a 

 Belemnite now before me is so completely enclosed, as to have led 

 in the first place to the supposition that it was wholly coralline, 

 until by an accidental fracture the unmistakeable structure of the 

 Belemnite was revealed. 



Ehizangia elongata. Dune. sp. PI. XIV. Figs. 10 and 11. 

 Fodoseris elongata, Duncan. Supp. Brit. Foss. Cor. pt. ii. p. 26, pi. ix. fig. 16-17, 



1868. 

 Although, this species so much exceeds in height all others of the 

 genus, I cannot detect any generic differences. Specifically Bhizangia 

 elongata differs also from B. mamilliformis in having the dissepiments 

 placed more on one level, that is, they collectively form masses 

 which are more clearly defined and more nearly horizontal. In the 

 latter species the layers of endotheca are more or less saucer-shaped, 

 and when the convex calicular surface has been rubbed smooth and 

 polished, they appear as rings, one within the other, having some- 

 thing the appearance of wall within wall.'^ In Bhizangia elongata 

 these layers of dissepiments are seen when a vertical section of the 

 corallum is made. 



Genus Leptophtllia, Eeuss. 

 Turbinoseris, Duncan. 

 For a long time I have believed that the genera Lepfophyllia and 

 Turbinoseris were one and the same. Although I had not made such 



^ See that gentleman's very interesting paper on the Eed Chalk of Hunstanton, in 

 the twenty-fifth volume of the Joiirnal of the Geological Society. 



* A horizontal section of a corallite, if only a little way below the calice, should 

 correspond as nearly as is practicable with the surface of the calice, for otherwise 

 some <'f the septa would be cut through much lower down than others. Indeed, the 

 same septum would be reduced very unequally, and the endotheca more exposed in 

 one place than another. As, however, there is no reason to su-p^iose, puma Jhcit^, 

 that any important difference exists between the two sides of a tali corallum, a 

 horizontal section taken low down seems unobjectionable. 



