60 EXPLANATION OF THE PLATES. 
hope, May Hill, and Llandeilo districts. In the Lower Ludlow of the 
Malvern and Abberley districts; and in the Aymestry limestone of the 
Malvern and Usk districts. In Ireland it occurs with P. Knightii in the 
Croaghmarhin (? Aymestry) beds, Dunquin, Dingle district, Co. Kerry. 
Gosva. : 
Fic. 6.—a, b. RHYNCHONELLA BOREALIS, Schlotheim. 
Terebratula lacunosa and bidentata, Sil. Syst., pp. 624, 5. R. borealis, Sil., 
4th ed., pl. xxii, figs. 4, 5. . 
a,b. Original. Front and back view of the same shell ; Wenlock limestone, 
Wenlock Edge. Mus. G. 8S. I. 
LLANDOVERY and WENtocK.—Sil., 4th ed., p. 527. ‘In Britain, Rh. 
borealis and its varieties diodonta and bidenta range from the Lower Llan- 
dovery to the Upper Ludlow, but are most abundant in the Wenlock lime- 
stone. Brit. Sil. Brach., p. 177. Lower Llandovery rocks, east of Mech- 
lin; Upper Llandovery, at Chirbury, Malverns; Bogmine, near Shelve, 
Shropshire. M. G. S., vol. ili., pp. 278, 361, 362. In Wenlock and Lud- 
low rocks. ‘‘ R. borealis is by far the most common species of Brachio- 
pod.” Sil., 4th ed., p. 121. Many Upper Silurian localities are re- 
corded for this abundant shell in the Malvern, Abberley, Woolhope, May 
Hill, Usk, Llandeilo, Freshwater, and Marloes districts, Mem. G. S., 
vol. ii., part i., pp. 279, 80. In Ireland, it has been collected from Wen- 
lock rocks at Ferriter’s Cove, and in ? Wenlock limestone, at Caherconree, 
Co. Kerry. Mus. G. 8S. I. 
Fig. 7.—a, 6. ORTHIS ELEGANTULA, Dalman. 
O. orbicularis, and O. canalis, Sil. Syst., pp. 611, 640. 
O. elegantula, Sil., 4th ed., pl. v., fig. 5; ix., fig. 19; xx., fig. 12. Brit. 
Sil. Brach., p. 211. 
a, b. Original. Two views of the same shell in Wenlock limestone from 
Whitfield, Tortworth. Mus. G. S. I. 
LLANDEILO to LupLow.—Sil., 4th ed., p. 526. The wide range of this very 
abundant and highly characteristic Silurian fossil is alluded to in the work 
cited ‘as being equally abundant in both divisions ;” zb¢d., p. 225. It is so 
universally distributed throughout the formation that it would be almost 
needless to specify the localities. In the Mem. of the Geol. Surv., vol. iii., 
pp- 258, 9, many localities are enumerated in Upper Llandeilo and 
Caradoe rocks in North Wales. In Lower and Upper Llandovery 
also, ibid., p. 277; and -in Wenlock rocks, N. Wales, wbid., p. 277. 
In Mem. Geol. Surv., vol. ii., part i, pp. 287, 8, many localities 
for this species are recorded; in Upper Llandovery, Wenlock, and 
Ludiow rocks, both in North and South Wales, Herefordshire, Shrop- 
shire, Gloucestershire, &c; Horderly and Coniston in Westmoreland are 
mentioned as additional Lower Silurian localities, and Dudley in Upper 
Silurian. Cat. Brit. Foss. (1854), p. 140. In Cornwall it is said to occur 
at Gorran Haven; Sil., 4th ed., p. 145; and Scotland, in Caradoc and 
Llandovery beds on the banks of Girvan Water, Ayrshire ; idid., p. 156; 
and the Wenlock shales of the Pentland Hills, near Edinburgh. _ Brit. Sil. 
Brach., p. 213. In Ireland it has been obtained from Caradoc- Bala beds 
at Portraine and Lambay, Co. Dublin; and from Wenlock rocks at 
Clogher, Co. Kerry; Kilbride, Cong, Co. Galway ; and Holyford, Co. 
Tipperary. Mus. G.S. I. 
