624 



SHELLS OF THE WENLOCK LIMESTONE. 



with radiating furrows, which increase in number towards the margin, and are crossed by un- 

 dulating laminae ; valves equally convex. Length | inch, width the same. 



Distinguished from A. affinis, PI. 6. f. 5. by the equally convex valves, and their more orbi- 

 cular form. 



Loc. Benthall Edge and oilier places in the Wenlock Edge. 

 Spirifer radiatus f. 6. (M. C. t. 493.) A very neatly striated shell, which can hardly be confounded 

 with any other. Length 14 lines; width 16 lines; depth of each valve 6 lines. 



Although this shell occurs in other situations, it is most abundant in the Wenlock and 

 Dudley Limestone. 



Loc. Wenlock and Dudley ; Tynewidd, Caermarth ensh ire ; Abberley Lodge. 

 Spirifer octoplicatus ? f. y . {M. C. t. 562. f. 2, 3.) Our specimen is smaller than those figured in 

 Min. Con., but otherwise agrees with them. The surface is nearly smooth, the plaits 4 on each 

 side of the central one. Length 2\ lines ; width 4i lines. Fragments that appear to be 

 portions of this species, have been met with in several parts of the Silurian System, but not 

 perfect enough to be identified. 

 Loc. Abberley ; Dudley. 



Spirifer crispus? f. 8. (Delthyris crispa } Dalm. I. c. p. 122. t. hi. f. 6. His. Pet. Suec, p. 73. t. xxi. 

 f. 5.) Transversely elongated, gibbose, plaited; plaits 5 or *J, crossed by elevated laminae ; 

 beaks remote; extremity of the hinge line obtuse. Length 3^ lines; width 5^ lines, often 

 larger. 



In some specimens of this shell, the transverse laminae are so prominent as to lead us to 



think they belong to D. sulcata, Hisinger, only they do not show the projecting lateral angles 



which distinguish that species. 



Loc. Dudley; Walsall; Wenlock, [very frequent). 

 Orthis rustica, f. 9. Transversely oblong:, rather square, depressed, uneven, with many rounded 



radii, which become more numerous towards the margin ; front straight or slightly elevated. 



Length 1 inch 1 line; width 1^ inch. 



The hinge area is triangular and rather large ; radii between 40 and 50. 



Loc. Wenlock; Valley of Woolhope. 

 Orthis alternata? (See PI. 19. f. 6.) Also Caradoc Sandstone. 



Loc. Abberley Lodge. 



Terebratula lacunosa, Linn. f. 10. & PI. 5. f. 19.; also Upper Ludlow Rock. Schloth. Nach. 1. p. 68. 

 t. xx. f. 6. T. borealis, Schl. Von Buch, Tereb. p. 67- The difficulty in distinguishing between 

 the allied species of plaited Terebratula, (especially from fragments only) has induced us to, 

 figure what may be called similar shells on the Upper Ludlow and Wenlock Limestone plates. 

 It is not impossible, however, that they may be different species, although we cannot, in the 

 specimens we have had to compare, find a distinguishing mark. T. lacunosa of Von Buch be- 

 longs to the Oolitic Series ; and is probably T. intermedia of Min. Con. Length 9 lines ; width 

 11 lines. 



Loc. Wenlock Edge ; Nash Lime Scar, Presteign ; Wallsall. 

 Terebratula crispata, f. 11. Rhomboidal, convex, transverse, subtrilobate, acutely plaited; plaits 



about 18, all terminating in the front, about 6 of them raised in the middle; sides smooth ; 



beaks small. Length 10 lines ; width 11 lines. 



Loc. Nash Scar, and other places in Radnorshire. 

 Terebratula imbricata, f. 12. Obovate, transverse, 3-lobed, plaited; plaits twice or thrice forked, 



