ORDOVICIAN AND SILURIAN BRACHIOPODA OF THE GIRVAN DISTRICT. 913 



Dimensions. — Length, 6*5 mm. ; width, 8 "5 mm. 



Horizon. — Saugh Hill Group. 



Locality. — Woodland Point. 



Remarks. — This species differs from Sir. monilifera of the Chair of Kildare 

 Limestone in the frilled instead of nodulated edges of the concentric lamellae and 

 in the more sharply bounded sinus and better defined fold. From Str. Grayi, 

 Dav., # of the Wenlock Limestone it is distinguished by its symmetry and by the 

 presence of the fold on the brachial valve. It is with pleasure I dedicate this 

 species to Dr John Horne, F.R.S. 



Genus Cliftonia, Foerste. 



Cliftonia Gray as (Davidson, emend.). 



(Plate XX, figs. 26, 27.) 



1870. Triplesia Grayise, Davidson, Man. Brit. Foss. Brack., vol. iii, p. 198, pi. xxiv, figs. 31, 32, 



(]pl. xxv, figs. 9, 10, 11). 

 1883. Triplesia^ Grayi, Davidson, op. cit., vol. v, Silur. Suppl., p. 144, pi. viii, fig. 32. 



The description of this species was given by Davidson in a sufficiently complete 

 manner, but his figures make the length of the hinge-line too great, the prominence 

 and angularity of the cardinal angles too marked, and the strength of the radial 

 ornamentation somewhat exaggerated. There seem to be also minute pits between 

 the radial lines, a feature which he *lid not mention. There is a small foramen at the 

 apex of the beak, as he suspected ; but the deltidial plate covering the delthyrium is 

 not broad nor elevated along its middle, as his figures indicate, being high, narrow, 

 and simple, as in typical examples of Triplecia and its congener Cliftonia, which has 

 been established by Foerste t to contain the radially striated members which Hall 

 and Clarke | doubtfully retained in Triplecia. The original type-specimens of 

 CI. Gray sb described by Davidson came from Craighead (op. cit., pi. xxiv, figs. 31, 

 32), and other examples were stated by him to occur in a green breccia in Pen- 

 whapple Glen, but the latter statement I am unable to substantiate. 



Horizon. — Stinchar Limestone Group. 



Locality. — Craighead. 



Cliftonia Andersoni, sp. nov. 

 (Plate XXI, figs. 1-4, ? 5.) 



1883. Triplesia 1 spiriferoides, M'Coy, Davidson (pars), Mon. Brit. Foss. Brack., vol. v, Silur. Suppl., 

 p. 146, pi. viii, fig. 30 (non Strophomena spiriferoides, M'Coy, Ann. Nat. Hist., vol. viii, 

 1851, p. 402). 



1883. Orthis biforata, Schlotheim, Davidson (pars), ibid., p. 181. 

 ! 1883. Rhynckonella nasuta, M'Coy, Davidson (pars), ibid., p. 160, pi. x, tig. 21. 



Shell transversely elliptical to subquadrate, biconvex, more or less inflated ; 



hinge-line less than width of shell ; cardinal angles rounded. Pedicle-valve slightly 



* Davidson, op. cit, p. 141, pi. xiii, figs. 14-22. 



t Eastman-Zittel, Text-book of Palmont. (2nd edit. 1913), p. 387. 



% Hall and Clarke, op. cit., Brach., i, p. 271. 



