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 LVII.

Fossil Shells.

Figs. 1, & 3. Upper and under view of a discoidal spiral univalve shell (Euomphalus pentangulatus, of Sowerby), from the mountain limestone of Derbyshire. The extinct genus Euomphalus, a name suggestive of the deeply excavated disk, comprises many species which occur in the Silurian, Devonian, and Carboniferous formations. The shell has chambers, or rather obsolete cavities sealed up by a shelly partition, in the abandoned part of the spire.[52]

[52] Medals of Creation, pp. 425-427.

Fig. 2. An elegant univalve shell, completely silicified or transmuted into flint (Natica canrena, of Parkinson, Natica Gentii, of Sowerby), from the upper greensand of Blackdown.

Figs. 4, & 6. Two views of the same specimen; a univalve (Nerita conoidea, of Lamarck), in which the apex or upper part is destroyed, and the interior of the shell is filled with yellowish brown chalcedony; in fig. 4, a cast of the spire is seen, and in fig. 6, the mouth of the shell, with the chalcedony partially filling up the interior. From tertiary strata near Paris.

Fig. 5. A beautiful fossil univalve shell, from the "Red Crag" of Suffolk, known to collectors as the "Essex reversed whelk," from the spire being coiled in the opposite direction to the common mode; the mouth is consequently situated to the left of the observer; the same species occurs with the spire in the usual direction. This shell is the Murex (Fusus) contrarius, of Parkinson.

Figs. 7, & 8. Under and upper view of another species of Euomphalus (E. rugosus, of Sowerby), from the Wenlock limestone, Dudley.