^{page 301 note 1} Descr. Anim. Fos. Bleiberg, p. 95.Google Scholar

^{page 302 note 1} Plate 160, fig. 7.

^{page 302 note 2} Ibid fig. 6.

^{page 302 note 3} Ralph Tate, in Woodward's Manual of Mollusca, 1868, second edition, p. 412.Google Scholar

^{page 303 note 1} The Lower Coal-measures of some writers.

^{page 303 note 2} The Survey specimens were collected by Messrs. Bennie and Macconochie.

^{page 303 note 3} Gr. rice.Google Scholar

^{page 304 note 1} Synopsis Garb. Fossils, 1844, p. 94.Google Scholar

^{page 304 note 2} My friend Mr. C. W. Peach has lately shown me another specimen of a valve possessing the small ears of this species, and ornamented with the V-striæ of P. Sowerbii. I find that in some notes attached to the description of pernopeeten Shumardianius, Winchell, Messrs. Meek and Worthen state that one of them (Mr. Meek) has described, in the “Report on the Coal-measure Fossils of Nebraska” (a work I have unfortunately not seen), a shell with the hinge-line in one valve straight, and in the other forming, at the beaks, a retreating angle (Illinois Geol. Rep. iii. page 454). It may be that the two valves of P. Sowerbii differed in a somewhat analogous manner; this, however, is a point which can only be proved by those possessing specimens showing the valves in union. Messrs. Meek arid Worthen point out the resemblance of P. Shumardianus to P. Sowerbii.

^{page 305 note 1} Salter, Mems. Geol Survey England and Wales, Country around Wigan, 1862, p. 35, fig. 1, b.Google Scholar

^{page 305 note 2} Synop. Garb. Fos. 1844, p. 78, t. 13, fig. 15.Google Scholar

^{page 305 note 3} Recorded as Anomia eorrugala by Messrs. Armstrong and Young, from Boghead, itl a thin band of Limestone, in the Upper Black Shale, and Dalrey, Ayrshire, in the LoWer Limestone. (Trans. Geol. Soc. Glasgow, iii; app. p. 45:)