CORALS FROM THE MOUNTAIN LIMESTONE. 185 



that the central area is distinct from the preceding one ; and that, in the central area, the 

 oblique lines, resembling a small tent, indicate the position of the small tabulae which are 

 crossed by the principal septa. 



Height of the corallum (in the large specimens) 2| inches ; diameter of the calice very 

 variable. 



Found at Oswestry; Nunney, near Frome; Castleton, Derbyshire; Wellington, in 

 Shropshire ; and, according to Professor M'Coy, at Beith, Ayrshire. 



Specimens are in the Collections of the Museum of Practical Geology, of Bristol, of 

 Mr. Bowerbank, &c. 



This species is characterised by its well-developed columella, and the very regular 

 arrangement of its septa. 



The Fossil mentioned by Col. Portlock under the name of Turbinolia mitrata} and 

 found by that Geologist in the carboniferous formation at Benburb, appears to belong to 

 this species. 



2. Clisiophylltjm coniseptum. Tab. XXXVII, figs. 5, 5«. 



Cyathophyllum coniseptum, Keyserling, Reise in Petschora, p. 164, pi. ii, fig. 2, 1846. 

 Cyathaxonia conisepta, D'Orbigny, Prodr. de Pal., t. i, p. 158, 1850. 

 Clisiophyllum coniseptum, Milne Edwards and Jules Haime, Pol. Foss. des Terr. Palseoz., 



p. 411, 1851. 



Corallum cylindro-conical, very tall, curved, and presenting well-marked, but small 

 accretion ridges. Calice circular. Colwmellarian protuberance conical, prominent, and 

 bearing at its summit a small columellarian lamella. Septa not very numerous (60 or 70), 

 thin, unequally developed alternately, some of the largest advancing quite to the centre of 

 the calice, and ascending the columellarian protuberance, under the form of flexuous 

 ridges. 



Height of the corallum, in general, 3 or 4 inches, and diameter of the calice about 

 \\ inch; sometimes much larger. 



Found at Ticknell, Mold, and Corwen, in England; and, according to Count 

 Keyserling, at Ylytsch in Russia. The large specimen figured in this Monograph belongs 

 to the Collection of the Bristol Museum. 



This species is remarkable for its elongate, cylindro-conical form, the smallness of the 

 central lamina placed at the top of the columellarian protuberance, and the great develop- 

 ment of this conical protuberance itself. C. coniseptum differs also from C. Hisingen~ by 



1 Report on the Geology of Londonderry, p. 331. 



2 Milne Edwards and Jules Haime, Monogr. des Polyp, des Terr. Palseoz., tab. vii, fig. 5. 



