622 



SHELLS OF THE WENLOCK LIMESTONE. 



Phragmoceras ? nautileum, PI. 10. f. 2, 3. Broad, compressed, much curved ; surface transversely 

 waved, waves forked. Length 3 inches ; ditto of aperture 2 inches. 



We have not seen the septa of this shell ; it has much the aspect of a Nautilus, but is too 

 irregular and has no columella. 



Loc. Myddleton Hall. In shale south of the Longmynd. 

 Lituites articulatus, PI. 11. f. 5 & 7. Volutions about 3, compressed, crossed by numerous ring-like 



costae, whose distance nearly equals their thickness. Diameter of the whorled portion l£ inch ; 



diameter of aperture 5 lines. 



This is suspected to be the involute portion of the same species of shell as that which is called 



Orthoceras articulatum, PL 5. f. 31. F. 7- is from a portion a little bent, and approaching the 



straight specimens, which might have been decidedly referred to this species, but that the in- 

 volute parts have not yet been found in the same rock with them. 



Loc. Ludlow escarpments ; Elton, f. 5. Shelderton, f. 7. 

 Lituites? Ibex, PI. 11. f. 6. (Inachus costatus? His. Petr. Suec, p. 38. t. xh, f. 2.) This figure represents 



an arched portion of probably Orthoceras Ibex, PI. 5. f. 30, which therefore approaches to 



Lituites, but we have not seen specimens perfect enough to settle the question. 



Loc. Ludlow ; Black Mountain near Clun, Long Mountain near Welch Pool. 

 Lituites giganteus, PI. 11. f. 4. Volutions about 3, close, rather compressed, crossed by many oblique 



arched ribs which are lost over the margin ; siphuncle central, aperture nearly square, rounded ; 



the inner whorls slightly indent those around them. Diameter of the last whorl 4^ inches ; 



length of the aperture If inch; width 1^ inch. 



Loc. Mocktree Hays ; Churn-bank near Ludlow. 

 Lituites tortuosus, PI. 11. f. 3. Irregularly curved; whorls diminishing very slowly; surface even ; 



septa numerous, curved only one way ; aperture oblong-ovate, imperfectly 5 angled. Length 



of aperture 10| lines, width 8 lines. 



We have only an imperfect specimen the chambers of which are filled with black limestone, 



and the place of the shell with sulphate of barytes, which adheres to the matrix, so that we 



cannot see the outer surface. 



Loc. Between Welch Pool and Berriw in black calcareous nodules. 

 Bellerophon dilatatus. (See PI. 12. f. 23, 24.) Also Wenlock Limestone. 

 Loc. Kingsland. 



FOSSIL SHELLS OF THE WENLOCK LIMESTONE, 



PLATE XII. 



Leptmna euglypha, Productus euglyphus passim, f. 1. {palm. Act. Holm., 1827. p. 108. t. i. f. 3 ; His. 

 Pet. Suec, p. 69. t. xx. f. 4.) Sub-prismatic, three-angled, with an obtuse front; flattened 

 above ; surface covered with fine radiating, elevated lines and numerous slender ridges ; de- 

 pressed margin large ; hinge-area long, narrow, and straight. Length of flat portion 1 inch ; 

 width 1\ inches ; depth of front 1 inch. 



This shell varies in its form, the sides being sometimes less flat than in the figure; the 

 fine lines also are variable, sometimes becoming as large as the slender ridges between which 

 they occur ; the sides are extended at the extremities of the hinge-line, and form projecting 



