A Pictorial Atlas of Fossil Remains, consisting of coloured illustrations selected from Parkinson's "Organic remains of a former world," and Artis's "Antediluvian phytology."

by Gideon Algernon Mantell

Plate LIX.

PLATE LIX.

Fossil Cephalopoda, &c.

Fig. 1. A fossil shell named Hippurite (Hippurites bioculatus, of D'Orbigny), from the south of France. This shell belongs to a family termed Rudistes, whose characters are somewhat problematical,—some naturalists referring them to the bivalves, and others to the univalves. The Hippurite is generally of an elongated conical form, and has internally two obtuse longitudinal ridges; the base is sometimes partitioned by transverse septa.

Fig. 5, is a longitudinal section of a specimen in which septa are displayed. The aperture is closed by a moveable operculum, or upper valve, as in the specimen fig. 1. The substance of the shell is cellular and very thick, and when fractured, resembles that of the lamelliferous corals. Some kinds attain a large size, and are called "petrified horns" by the inhabitants of the districts in the Pyrenees where they abound. Though Hippurites are abundant in the chalk of the south of France, and in Spain and Portugal, none have been found in England. The Spherulite, a nearly allied genus, which has no internal longitudinal ridges, occurs in the chalk of Sussex: it was first discovered near Lewes. (Spherulites Mortoni, of Mantell.)[54]

[54] Medals of Creation, p. 428.

Fig. 2. The siphuncle of a very large Orthoceratite ("related to the genus Ormoceras," Mr. Morris), from the Rhine.

Figs. 3 & 4, "show the direction in which the siphuncle in Orthoceratites intersects the septa."