62 EXPLANATION OF THE PLATES. 
PLATE XXTI. 
FOSSILS OF THE WENLOCK ROCKS. 
MOLLUSCA.—CONCHIFERA. 
Fig. 1.—PrerineA ORBICULARIS, J/‘Coy. 
Synopsis Sil. Foss. of Irel., p. 21., pl. ii., fig. 8. 
Original. Radiated valve, Carhoo, Dingle. Mus. G. 8. I. 
Wentocxk.—Sil., 4th ed., p. 529, “‘one of the largest and most plenti- 
ful” of the Aviculoid group, which are abundant in the Dingle District, 
ibid., p. 228. Also in Ludlow Rocks, Derrymore Glen, Co. Kerry. 
Mus. G. S. I. 
Fic. 2,—a-b. PrERINEA PLANULATA, Conrad. 
> 
Salter, Mem. Geol. Surv., vol. ii., pt. 1, p. 368, pl. xxiii, fig. 2-4. 
a. From fig. 3 in the vol. cited. 
b. Original. Enlarged portion of surface, showing concentric and 
paraee radiating strize. Wenlock Limestone, Wenlock Edge. Mus. 
G.S. I. 
LLANDOVERY TO LupLow.—Sil., 4th edition, p. 529; ‘‘a common Wenlock 
species doubtfully referred to this genus;” ibid., p. 228, distributed 
pretty generally through the Lower Ludlow and Wenlock rocks, abound- 
ing at Dudley and the neighbourhood, in the Shales; M. G. S., op, cit., 
p- 369. In Ireland it has been found, at Ferriter’s Cove, E., Clogher, 
and Cahirconree, Kerry, in Wenlock Rocks; Mus. G. 8. I. 
Fie. 3.—MopioLopsis ANTIQUA, Sowerby, sp. 
Modiola.—Sil. Syst., p. 628, pl. xiii., fig. 1. Modiolopsis ; Sil., 4th edition, 
p- 229, pl. xxiii, fig. 14. 
From Sil. Syst., pl. xiii, fig. 1. Wenlock Shale, Glass House Hill, East of 
May Hill, Gloucestershire. 
Wentocx.—Sil.,, 4th edition, p. 530; ‘a common species ;” ibid., p. 229. 
Fic. 4. —Mopio.orsis GRADATA, Salter, sp. 
Mytilus gradatus, Mem. Geol. Surv., vol. ii., pt. 1, p. 365, pl. xx. fig. 3, 4, 5. 
Modiolopsis gradata; Sil., 4th edition, p. 530; J£, Nilsson, ibid., p. 
229, Foss. 61, fig. 8. 
From Mem.- Geol. Surv., op. cit., pl. xx., fig. 4, ‘common in the 
Ludlow Rocks of Shropshire and South Wales ;” ibid. p. 363, 
WENLocK AND LupLow.—Sil., 4th edition, p. 550. 
