PECTUNCULUS. G9 



In P. obsoletus, Goldfuss, 1 the shell is oblique, and more oval and rounded in 

 form than in P. sublsevis. 



P. subpulvinatus, d'Archiac, 2 from the Tourtia of Tournay, is also more oblique 

 and has the posterior border more rounded. 



For the relation of this species to P. umbonatus, Sowerby, see p. 70. 



The two examples described by Keeping (vide supra) from the Lower Green- 

 sand of Upware appear to differ from P. sablseois in being less inflated and 

 in having a higher area, but the specimens are not sufficiently perfect to allow me 

 to give a definite opinion on their affinities. 



Types. — From Blackdown ; in the British Museum. 



Distribution. — Greensand of Blackdown (zones xi and xii) ; Lower Gault (zone 

 vi) of Folkestone (fide Price). 



Pectunculus umbonatus (Soiverhj), 1817. Plate XIV, figs. 8 a — c, 9 a— c, 10 a — c, 



11, 12. 



1817. Cardium umbonatum, J. Sowerbi/. Min. Couch., vol. ii, p. 128, pi. clvi, 



figs. 2-4. 

 1824. Pectunculus umbonatus, J. de C. Sowerbi/. Ibid., vol. v, p. 113, pi. ccclxxii, 



fig. 3. 

 1854. /. Morris. Cat. Brit. Foss., ed. 2, p. 220. 



1868. A. BriartandF. L. Cornet. Descript. de la Meule 



de Bracquegnies (Mem. Cour. et Mem. 

 des Sav. etraugers, Acad. lioy. Belg., 

 vol. xxxiv), p. Gl, pi. v, figs. 19, 20 ? 



Non 1837. A. Goldfuss. Petref. Germ., vol. ii, p. 160, pi. 



cxxvi, fig. 2. 

 ? — 1841. — — F. A. Romer. Die Verstein. des norddeutsch. 



Kreidet'ormut., p. 68. 



— 1816. A. E. Reuss. Die Verstein. der bohm. Kreide- 



t'ormat., pt. ii, p. 9, pi. xli, 

 fig. 20. 



— 1857. J. W. Salter. Quart. Journ. Geol. Soe-., vol. 



xiii, p. SG. (For remarks on 

 this form see Jukes-Browne, 

 Geol. Mag., 1S9S, p. 29.) 



Description. — Shell rather inflated and more or less circular or slightly sub- 

 quadrate, usually a little higher than long, nearly equilateral. Anterior margin 



1 'Petref. Germ.,' vol. ii (1837), p. 160, pi. cxxvi, fig. 4; Geinitz, "Das Elbthalgeb. in Sachsen " 

 ' Palaeontographica,' vol. xx, pt. i (1873), p. 223, pi. xlix, figs. 7 — 11. 



2 'Mem. Soc. Geol. de France,' ser. 2, vol. xii (1846), p. 306, pi. xv, fig. 2. 



