TRANSACTIONS OF THE SECTIONS. 88 



On a new Genus of Rwjous Corah from tJte Mountain-Limestone of Scotland. 



By James Thomson, F.G.S. 



The author stated that this genus was closely allied to Dana's genus Clissio- 

 Ithylltim. It, however, diftered from that genus, not ouljr in its external aspect, 

 but also very materially in the internal structure. He briefly^ described the cha- 

 racteristics by which the genus Clissiophyllum can be distinguished, viz. that there 

 was always a conical boss in the centre of the calice, and that in the centre of the 

 corallum there was always a coluniellarian line, which passed from the apex of the 

 boss down the centre of the corallum, and terminated at the inferior extremity ; 

 and that there were lamellie which passed from the inner margin of the primary 

 septa into the columella in the centre of the calice, and that they were united by 

 convex endothecal dissepiments, convexity upwards and outwards. 



The genus he proposed to establish can readily be distinguished from Clissio- 

 phyllnm, not only externally, but also fi-om the internal structure. The boss in the 

 centre of the calice never assumes a conical aspect, and is only slightly raised above 

 the inner margin of the primary septa, and is divided in tAvo by a strong middle 

 ridge, from which the author derives the generic name. He is confident that the 

 structure of the central portion of the corallum is more characteristic for generic 

 distinction than any other part. We cannot, however, rely alone on that or any 

 other part of the corallum for either generic or specific distinction. If it is taken, 

 however, in conjunction with the other parts of the internal structure, it will enable 

 ns to readily decide as to what group the form ought to be classified with for 

 diagnostic purposes. 



DiBUNOPHYLiiUM, gen. nov., Thomson. 



Gmeric Characters. Corallum simple, cylindro-conical, tall in some forms, whilst 

 in others it is short and more or less turbinate and marked with ii-regular accre- 

 tion-ridges. Calice moderately deep, thin around the margin in some forms, 

 whilst in others it is everted. Septa thin, with lamina) for fully half their length 

 from the inner margin, wherein they become flexuous. Coluniellarian boss slightly 

 raised above the inner margin of the primary septa, with a prominent middle ridge, 

 which, in a transverse section, is seen to be formed of convex endothecal dissepi- 

 ments, convexity outwards. The outer area is formed of lamellffi, which pass from 

 the inner margin of the primary septa to the convex dissepiments of the median 

 ridge. 



A vertical section shows that the central area is dissimilar from the genus Clis- 

 siophylhim. Instead of a coluniellarian line in the centre of the corallum, as in the 

 latter genus, there is a system of convex dissepiments, which converge to the centre, 

 convexity outwards and' upwards ; whilst in other foinis there are several vertical 

 plates passing down the centre of the corallum, and each are united by concave 

 endothecal dissepiments. Fossula with small septa in it. 



This genus is established for the reception of a group of corals that the author 

 discovered many years ago in Ponneil Water, five miles south of Lesmahagow, 

 Lanarkshire. He has subsequently found them in several localities in the central 

 valley of Scotland, details of which will be given hereafter, when the specific cha- 

 racteristics wiU be described in detail. 



On the Occurrence of a Loiver Boulder-clan or Till tvith Shells, in the Counties 

 of Down and Mayo, Ireland. By William A. Traill, M.A.I, (blaster in 

 Engineering), F.H.G.S.I., H.M. Geological Survey of Ireland. 



The author, in introducing his subject, briefly reviewed the divisions of the Drift 

 series, especially so far as they related to the occuiTence of shells in the lower boulder- 

 clay, which he had met with in several localities in Ireland, and hoped that such 

 places, and the mode of occurrence of such, would be carefully examined and noted, 

 as only a few instances of these shelly drifts in Ireland had been recorded. 



After long examination in the county Down, he was fortunate enough to find 

 some shells in the undoubted lower boulder-clay in four localities adjacent to the 



