siphon. The base of the shell beyond the last plate presents a swelling cavity, wherein the body of the animal seems to have been partly contained.
The Orthoceratites are straight and conical, and bear the same relation to the Nautili which Baculites (see Pl. 44, Fig. 5) bear to Ammonites; the Orthoceratites, with their simple transverse septa, resembling straight Nautili; and the Baculites, with a sinuous septa, having the appearance of straight Ammonites. They vary considerably in external figure, and also in size; some of the largest species exceeding a yard in length, and half a foot in diameter. A single specimen has been known to contain nearly seventy air chambers. The body of the animal which required so large a Hoat to balance it, must have greatly exceeded, in all its proportions, the most gigantic of our recent Cephalopods; and the vast number of Orthoceratites that are occasionally crowded together in a single block of stone, shows how abundantly they must have swarmed in the waters of the early seas. These shells are found in the greatest numbers in blocks of marble, of a dark red colour, from the transition Limestone of Oeland, which some years ago was imported largely to various parts of Europe for architectural purposes.[1]
Lituite.
Together with the Orthoceratite, in the Transition Limestone
of Oeland, there occurs a cognate genus of Chambered
the Lias at Lyme, and another species in Alpine Limestone of the Oolitc
formation, at Halstadt, in the Tyrol.
- ↑ Part of the pavement in Hampton Court Palace, that of the hall of University College, Oxford, and several tombs of the kings of Poland in the cathedral at Cracow, are formed of this marble, in which many shells of Orthoceratites are discoverable. The largest known species are found in the Carboniferous limestone of Closeburn, near Edinburgh, being nearly of the size of a man's thigh. The presence of such gigantic Mollusks seems to indicate a highly exalted temperature, in the then existing climate of these northern regions of Europe. See Sowerby's Min. Con.
