82 EXPLANATION OF THE PLATES. 
probably occurring also in the Upper Llandovery Rock, of the Obelisk, 
Eastnor Park, Herefordshire. M. G.S., Mon.i., pp. 92, 3. 
Fig. 4,._EURYPTERUS PYGMZUS, Salter. 
Quart. Journ. Geol. Soc., vol. xv., p. 232, pl. x., figs. 4-8. 
Partly restored from figs. 4 and €. Downton Sandstone, Kington. 
Mr. R. Banks’ collection. 
Luptow and Passacr Brps.—Sil., 4th ed., p. 518. Drvontan. Forfar, 
Woodward and Salter’s Chart, p. 24. ‘‘ A small and abundant species 
in the Tilestones at Kington and Ludlow.” Sil., 4th ed., p. 239. 
Fic. 5.—PTERYGOTUS BILOBUs, Salter. 
Himantopterus bilobus, Salter. Quart. Journ. Geol. Soc., vol. xii., p. 29, fig. 1. 
P. bilobus, Salter. Mem. Geol. Surv., Mon. i., p. 39 
Original. A young example; reduced one-third, from Uppermost Ludlow 
Rocks, Lesmahago, Lanarkshire. Mus. Geol. Surv. Irel. 
Luptow.—Sil., 4th ed., p. 521. 
PISCES. 
Fig. 6.—PTERASPIS TRUNCATUS, Hualey and Salter. 
Quart. Journ. Geol. Soc., vol. xii., p. 100, pl. i1., fig. 1. 
Original. Cephalic buckler or head. Uppermost Ludlow, “ Passage Beds,” 
Kington, Ludlow. Mus. G. S. I. 
Lupiow and PassaGE Brps.—Sil., 4th ed., p. 536. 
Fic. 7. ONCHUS TENUISTRIATUS, Agassiz. 
Sil. Syst., pl. iv., figs. 57-59. Sil., 4th ed., pl. xxxv., figs. 15-17. 
Fin-spine of a shark-like fish. From the figure in Sil. Syst., pl. iv., fig. 58. 
Upper Ludlow, Bone-bed, Ludford, near Ludlow. 
Lupiow.—Sil., 4th ed., p. 536. 
Fia. 8.—a, b. Orncnus Murcuisoni, Agassiz. 
Sil. Syst., pl. iv., figs. 9-11. Sil., 4th ed., pl. xxxv., figs. 13, 14. 
a, b. Fin-spines of a shark-like fish, ‘‘ the most common species.” 
From the figures in Sil. Syst., pl. iv., figs. 9-11. Upper Ludlow, Bone-bed, 
Ludford, near Ludlow. 
Lup.ow and ? PassaGr Breps.—Sil., 4th ed., p. 536. 
Fic. 9.—a, 6, c. PLECTRODUS MIRABILIS, Agassiz. 
Sil. Syst., pl. iv., figs. 14-26. Sil., 4th ed., pl. xxxv., figs. 3-8. 
a, b. Natural size. c, 9b. enlarged ; probably portions of the jaws and teeth 
of a small ? ganoid fish. From the figures in Sil. Syst., pl. iv., 
figs, 20, 21, 26. Upper Ludlow, Bone-bed, Ludford, near Ludlow. 
Lupiow and Passace Beps.—Sil., 4th ed., p. 536. 
