Table 9 fig: 5 pag: 226. To the rt reverend father in god john ld. Bishop of ely, this plate, in memory of his lordships many & great favours is gratefully dedicated by j. M. M. A. & f. R. S. [john morton, master of arts and fellow of the royal society]. Text: "72. Proceed we now to the turbinated shells and stones of the second class, that is, those that are spirally turn'd, and of a flat depressed shape. These are of two kinds: in the first, the smaller convolutions do not appear externally, being swallow'd up, as it were, by the largest, that is, by the outmost wreath. These are called nautili or sailers. In the second, the whole number of wreaths appear plainly: and the shell is generally of a more depressed shape. To these i shall assign the name of conchae ammoniae, and to the stones form'd in them of ammonitae; which names are given by naturalists, as in some manner they resemble those wreathed horns which are usually seen upon the heads of the images of jupiter ammon. Most of these of both kinds, i now speak of the fossil ones, have their cavitity divided into sundry cells or apartments, by means of transverse shelly partitions, as in the sea nautilis: and have these partitions placed at certain short distances one from another, as in that. The fossil nautili, and so for the ammoniae with us, are always found filled with a stoney or other like matter. The shells of this second sort that are found enclosing and covering a stoney matter: as also the stones that originally formed in them, that are now found disclos'd and uncover'd, are generally called in england snake-stones and serpentine stones; because in the fashion of their wreath-wrok they somewhat resemble a folded snake. To many of the stones thus formed there adhere some remains of the shell that form'd them; especially in the intervals of the striae, and in the central part of them; these, as being less prominent, being less expos'd to injury. But with us, 'tis not very usual to meet with any of the ammoniae entire. Some of them have quite disappear'd; excepting only their shelly partitions, by authors usually called diaphragms, which lying enclos'd, and as it were, wedged in stone, have been generally well preserv'd from those external injuries that destroy'd the exteriour part: and so the stone is left bare. . "74. Of the conchae ammoniae, and ammonitae, we have several sorts. They are as follows. . "82. Some other sorts of ammoniae we have had here, as appears by the figure of the amonitae i am now about to describe. The ammonitae not yet describ'd, and that appear to have been form'd in ammoniae of different species from any of the foregoing, are these:. . "83. (2. ) a four-wreath'd ammonites less flat, and more thinly striated, than is the former: with strait striae or ridges that terminate each in a little knob upon the edge of the rim [t. 9. F. 5. ]: with a pretty broad rim: and a crest drawn along it, betwixt the two rows of knobs. The diameter about an inch and half. We find it in clay at marston-trussel, and elsewhere. ". Date: 1712.
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