CONULARIA TENUIS. 21 



layers of the shell, ridging up the inner layer only (PI. I, fig. 11). The 

 ornamentation appears to be almost intermediate between that of G. aspersa, 

 Lindstrom, and that of G. carta, Sandberger. In the young shell the longitudinal 

 ridges are almost stronger than the transverse (PI. I, fig. 10 e), but in the adult 

 both are equally strong (PL I, figs. 12 a, 12 b). The furrows are only fine grooves 

 between neighbouring ridges. The shell is fairly thick, and consists of two 

 distinct layers. 



Affinities. — This species is closely related to G. sp. cf. aspersa from the Bala, 

 and to 0. aspersa from the Ludlow. It is distinguished from both by the form of 

 the transverse section, by the small angles of the faces, and by the ornamentation. 



Horizon and Locality. — Middle and Upper Llandovery : Woodland Point and 

 Penkill, Girvan. 



Type. — Mrs. Gray's Collection. 



Conularia sp. cf. aspersa, Lindstrom. Plate I, figs. 13 — 14. 



In the highest Bala rocks of Thraive Glen, Girvan, and at the same horizon at 

 Horderley, incomplete fragments of a Conularian are found. Although specimens 

 are fairly numerous, only one (PI. I, fig. 13) gives any detail of the form of the 

 shell. This specimen, so far as can be ascertained, is the external cast of one face, 

 which tapers uniformly at an angle of about 25°. The internal longitudinal " septa," 

 so characteristic of G. aspersa, are also found here, and from the figured specimen 

 appear to be present, not only in pairs down the centres of the faces, but also at 

 the angles of the pyramid (PI. I, fig. 13 a). This appearance may, however, be 

 misleading, and cannot be confirmed from other specimens, as these, though 

 showing the septa, are all very incomplete and broken. No shell is preserved, 

 but the ornamentation is well seen in the casts, and closely resembles that of 

 G. aspersa (PI. I, fig. 13 b). It varies much in coarseness with the size of the shell 

 (cf. PI. I, figs. 13 b and 14 a,). This species is closely allied to C. punctata and 

 to G. aspersa, from both of which it may provisionally be distinguished by the 

 presence of the " septa " at the angles of the pyramid. 



The figured specimen is in Mrs. Gray's Collection, and comes from the Starfish 

 Bed, Girvan. 



Conularia tenuis, sp. nov. Plate II, figs. 1 — 3. 



1878. Conularia, sp. hid., E. Etheridge, juu., Quart. Journ. Geol. Soc, vol. xxxiv, p. 19. 



Diagnosis. — Shell large, very thin, tapering uniformly ; cross-section square. 

 Faces equal, flat; apical angle 10° — 14°. Marginal grooves shallow and incon- 



