199 



CHAPTER X.^ 

 MOUNTAIN LIMESTONE FOSSILS. 



Cyathopsis? eruca (M'Coy). 



Sp. Char. Corallum very small, subcylindrical after a diameter 

 of 3 lines, whicli it reaches at 6 lines from the apex, slightly 

 curved ; length of large example 1 inch 2 lines, diameter Sp- 

 lines ; surface marked with coarse, longitudinal, obtuse lamellar 

 striae, three in the space of 1 line; radiating lamellae strong, 

 slightly irregular, connected by several curved thick transverse 

 vesicular plates in the horizontal section, one of the lamellae 

 stronger than the rest, and extending through the centre, 

 where it is either thickened or confounded with a slight 

 mesial boss of one of the transverse septa : vertical section, 

 middle third traversed by thick, subregular, transverse dia- 

 phragms, convex upwardly, three interdiaphragmatal spaces 

 in 1 line; outer third on each side formed of one or two 

 rows of irregular large cells, formed by the junction and occa- 

 sional duplicature of the deflected edges of the diaphragms. 



This so exactly resembles the Cyathaxonia cornu in size, shape 

 and general external appearance, that it might be very easily 

 confounded with it ; even externally, however, it might be di- 

 stinguished by the smaller number in a given space of its much 

 coarser lamellar vertical striae ; internally it is easily distinguished 

 by wanting the solid styliform axis, by the distinct transverse 

 vesicular plates between the lamellae in the horizontal section, 

 and the transverse septation, &c. of the vertical section. 



Very common in the black carboniferous limestone and shale 

 of Beith, Ayrshire. 



[Col. University of Cambridge.) 



Caninia subibicina (M'Coy). 



Sp, Char. Corallum much curved, increasing, when young, at 

 the rate of 6 lines in 1 inch to a diameter of 1 inch 3 lines, 

 after which it remains nearly cylindrical for 2 or 3 inches 

 more ; surface with a thin, nearly smooth epitheca, marked 

 with obsolete transverse undulations of growth ; when the 



* The species in this chapter date from the 'Annals ' for March 1861. 



