EXPLANATION OF THE PLATES. 49 
GASTEROPODA. 
Pie. 5.—a, 6. HOLOPELLA CANCELLATA, Sowerby, sp. 
Turritella, Sil. Syst., p. 642. Holopella, Sil., 4th ed., p. 532. 
a, b. From the figures in Sil. Syst., pl. xx., fig. 18. 
Carapoc, LLANDOovERY, and LupLtow.—Sil., 4th ed., p. 532. Localities in 
Lower Llandovery rocks at Presteign; Malvern; and Mandinam; ibid. 
Explanation of Plate x., fig. 14. Upper Llandovery rocks at Chirbury, 
Norbury, and Bogmine. Mem. Geol. Surv., vol. iti., p. 362. In con- 
glomerate ‘‘Pentamerus beds” at Golencoed, Pumsant. Mus. G. S. I. 
“ This our largest British species, often three inches long, is common to 
the Lower and Upper Llandovery, and abounds in still higher beds at the 
Bogmine, near Shelve, in Shropshire.” Sil., 4th ed., p. 212. 
Fig. 6.—MURCHISONIA ANGULATA, Sowerby, sp. 
Pleurotomaria, Sil. Syst., p. 641. Murchisonia, Sil., 4th ed., p. 532. 
From the figure in Sil. Syst., pl. xxi., fig. 20. 
LLANDOVERY.—Locality, Mandinam in Lower Llandovery rocks. Sil., 4th 
ed., Explanation of Plate x., fig. 13. 
5 
Fic. 7.—a, b. Trocnus ? MuLtirorauatus, M‘Coy. 
Silurian Fossils Ireland, p. 15. 
a. Original. A group of internal casts in decomposing sandstone from Boo- 
caun, Cong, Co. Galway. 
b. External shell; showing its many whirls. From the figure in Sil. Foss. of 
Trel., pl. i., fig. 14. 
Lianpovery.—Abundant at Boocaun and other localities near Cong, Co. 
Galway. Ibid. 
I can confirm Professor M‘Coy’s remarks as to the abundance of this 
species from my own observation in rocks of Llandovery age, in the 
county of Galway, particularly at Ballyweeaun, near Lough Coolin, 
where bands of these shells may be seen weathered out by the decomposi- 
tion of the hard sandstone.—W. H. B. 
HETEROPODA. 
Fig. 8.—BELLEROPHON TRILOBATUS, Sowerby. 
Silurian System, p. 604. = 
From the figure in Sil. Syst., pl. iii., fig. 16. Loc, Felindre. 
LLANDOVERY to Luptow.—Sil., 4th ed., p. 534. ? Upper Llandovery, 
Maume, Galway. Mus. G. S. I. Tortworth, and in Shropshire, Sil., 4th 
ed., pp. 90-213. Upper Ludlow, Felindre, ten miles W. of Knighton ; ibid. 
Explanation to Plate xxxiv., fig. 9. 
CEPHALOPODA. 
Fig. 9.—CYRTOCERAS APPROXIMATUM, Sowerby, sp. 
Orthoceras, Sil. Syst., p. 642. oh 
From the figure in Sil. Syst., pl. xxi., fig. 22. 
