Published online by Cambridge University Press: 01 May 2009
In this specimen one valve (the left) and a part of the dorsal region of the other, remain visible; the rest of the right valve being bent down, broken, and imbedded in the matrix. This is a finely micaceous, non-calcareous, grey mudstone, weathering ferruginous towards one edge, which probably abutted on a crack open to water and atmosphere.
The fossil, in the grey portion is darker than the matrix, and fairly represents the test of half of the carapace, with only a very thin lamina wanting, a broken edge of which is traceable (with a lens) near the ventral margin. This left valve measures 9·2 by 7·4 mm. It is subcircular, more boldly curved on the ventral than on the posterior margin, whilst the front margin is somewhat truncate, having a nearly straight edge from above downwards before it bends round into the ventral curve.
page 385 note 1 For the latest account of this genus and the several species here mentioned, see Geol. Surv. State of New York, Palæontology, by ProfHall, James and Clarke, J. M., vol. vii. 1888, pp. 166–181,Google Scholar plates 28–30. See also our Sixth Report (for 1888), Rep. Brit. Assoc. 1889, p. 180.Google Scholar
page 387 note 1 The Turkish Beyrichiœ above mentioned are briefly noticed also by MrSwan, W. R., in the Quart. Journ. Geol. Soc. vol. xx. (1864), p. 115.Google Scholar
page 387 note 2 In his Geological Conditions of the Eastern Part of European Turkey, Jahrb. der geol, K.K.. Reichsanstalt, vol. xx. 1870.Google Scholar
page 387 note 3 This specimen, collected by M. A. Dumont, was sent to Dr. Ferd. Roemer by M. G. Dewalque, who, having the care of the Museum of the Liége University, has allowed us to see the specimen. It is closely allied to, if not the same as our B. Devonica.
page 388 note 1 Geol. Mag. 1888, pp. 487–491, Pl. XIII.Google Scholar; 1882, pp. 157–8, Pl. IV. Fig. 3.