^{page 171 note 1} The segments are, of course, opaque, and the septa consequently appear white on a dark ground; in the drawings, however, this colouring is reversed, to secure uniformity with the transparent microscopic sections 2a–2d and 1j.

^{page 171 note 2} Strictly speaking, only Figs. 2d and 1d are in the dumonti phase, Figs. 2b, 2c, and 1b, lc, being in the vermicularis phase.

^{page 172 note 1} Prévost, Constant, “Description géologique du littoral de la France”: C.R. Acad. Sci. Paris, vol. xxix, 11 26th, 1849, pp. 615–622Google Scholar. The work of C. Prévost, “Sur les falaises de la Manche,” had been seen by Cuvier and Brongniart, who reported upon it to the Academy.