Smyth — Faunal Zones of Rush- Skerries Oarboniferous Section. 557 



In the immature stages of some specimens the counter septum and its 

 immediate neiglibours are grouped, so that their inner ends are parallel. 

 This often produces tlie appearance of a counter fossula. 



The exterior of the specimen described above is not known, but a 

 specimen from a slightly lower level in the Rush Conglomerate (R 11 a) 

 is coruute, costate, about 17 mm. long, and with a calyx 10 mm. in 

 diameter. 



Dr. Vaughan has sliown the author several slices made from specimens of 

 this coral collected some years ago at Malahide (Co. Dublin) in beds which 

 he correlates with the Rusli Slates. 



Bensiphi/Uiim aff. rufihidnnvi, Vau. (PI. XXXVI, fig. 4.) 



HoLMPATRiCK Limestone. 



Rush Conglomerate, top of R 10. 



This form agrees with the type in the remarkable regularity of tlie septa, 



thickening of their extremities, absence of alar breaks, constriction of the 



inner end of the fossula, and presence of rudimentary minor septa. 



It differs in the following respects: — It attains a greater size, the septa 

 are much stouter, tlie wall is not so thick in proportion, and the epitheca 

 bears well-mfirked costae. 



Several specimens were found near the middle of the Holinpatriok Lime- 

 stone and a single small specimen in the Rush Conglomerate, at the top of 

 R 10. These two horizons are (according to the correlation suggested in this 

 paper) at tiie top and bottom of Ca, respectively. 



KonincliophyUum densum, sp. nov. (PI. XXXVl, fig. 1.) 



HoLMPATRICK LlMESTONE. 



Form : — Conical. Length about 30 mm. Diameter of calyx about 

 30 mm. 



Tranverse section (diam. 25 mm.) :— External area composed of about ten 

 rows of vesicles regularly radiated by the unthickened major and minor 

 septa. Vesicles somewhat crowded near inner wall. Inner wall very distinct 

 owing to stereoplasmic thickening. Medial area radiated only by major 

 septa which are here strongly thickened. The thickening is less near the 

 inner wall, reaches a maximum further in, and the septa taper to a point 

 at their inner ends. The thickening affects all the major septa, but is 

 greater in tlie cardinal half. In the medial area there are about six rather 

 crowded tabular intersections showing that the tabulae were widely domed. 

 The cardinal fossula is very distinct, and lateral breaks are marked by short 



