SECTION OF THE PEBBLE.
SECTION OF THE PEBBLE.
We will now avail ourselves of the assistance of the lapidary, and divide the pebble in a longitudinal direction;—what a beautiful and interesting section is thus obtained! The markings observable on the fractured portion of the stone (see [Plate I, c]), are thus shown to have originated, as we surmised, from some organic body, which the flint, when fluid, had penetrated and enveloped. The enclosed fossil was obviously one of those soft marine zoophytes, allied to the Actiniæ or Sea-Anemones, which are of a globular, spherical, or inversely conical shape, and consist of a tough, jelly-like substance, permeated with tubes, disposed in a radiated manner around a central cavity, or digestive sac; a structure admitting of that constant supply and circulation of sea-water, which the economy of these curious forms of animal existence requires.
ISLE OF WIGHT PEBBLES.
The surface exposed by the division of the pebble, is an oblique vertical section of the petrified zoophyte. It shows a central canal filled with bluish-grey flint ([Plate II, c]), in a mass traversed by tubes or channels, which possess considerable beauty and variety of colour from an impregnation of iron.[L] A transverse section (see [Lign. 14. fig. 1]) would, of course, have a central spot, with rays proceeding thence to the circumference, as in the oblique fracture ([Plate I, c]).[M]
[L] Specimens of this kind form beautiful objects when polished, and are mounted as brooches by the lapidaries of Brighton, Bognor, and the Isle of Wight, who term them petrified sea-animal flowers. Mr. G. Fowlstone (4, Victoria Arcade) of Ryde, has many splendid examples, and also agates and jaspers, the genuine productions of the Island.
[M] [Note VII.] Isle of Wight Pebbles.
CHOANITES KONIGI.
The form of the original zoophyte when living, must have been that of an inverted cone or funnel, (hence the scientific name Choanite or funnel-like,) with a long cylindrical digestive cavity in the centre, from which tubes ramified through every part of the mass. It was attached to a rock, stone, or shell, by root-like fibres which spread out from its base; and its soft body was strengthened, as is the case in many sponges and animals of a similar nature, by numerous siliceous spines or spicula, which are often found in the flint and chalk (see [Lign. 10. fig. 5]).[N]