20 EXPLANATION OF THE PLATES. 
Moffat and Girvan, in Ayrshire. In Ireland it occurs in Lower Silurian 
shales (? Llandeilo Flags) at Bellewstown Hill, county of Meath.” Brit. 
Sil. Brach., p. 77. 
These Brachiopod Shells from the county of Meath, alluded to by Mr. David- 
son, associated with Didymograpsus Murchisonii, Diplograpsus pristis, 
&c., were amongst the old collections made by the late Mr. Flanagan, of 
the Geological Survey, and since examined by the author; they are very 
important fossils, as indicating strata of Llandeilo age; but, although the 
neighbourhood from which they were said to have been obtained has been 
searched on several occasions, corresponding specimens were not met with, 
although others equally interesting were collected. 
Fig. 4.—a, 6. OrtHIs ALATA, Sowerby, sp. 
Spirifer alata. Silurian System, pl. xxii, fig. 7. 
Orthis alata. Siluria, third edition, p. 55; Foss. 10, fig. 15, and pl. v., 
fig. 11. 
a0. "oth the original figure in the Silurian System above cited. 
LLANDEILO Fiacs.—Mount Pleasant, Caermarthen. ‘The author collected 
this species from black carbonaceous shales with Diplograpsus pristis, 
Dictyonema sociale, &c., at Cooksgrove, Bellewstown Hill, near Duleek, 
County of Meath—the locality from which the specimens previously alluded 
to were believed to have been obtained; the lithological character of the 
rock, in which they are imbedded, differs however considerably. 
Fic. 5.—a, 6. ORTHIS CALLIGRAMMA, Dalman, variety. 
From the figures in Mem. Geol. Surv., vol. iii., pl. xi. B, figs. 11, 12. 
Lower LianpEILo.—Cae-glyd, a locality rich in fossils, under the traps of 
Manod Bach, Ffestiniog ; also in the arenaceous mudstones of Lord’s Hill 
and other places, west of the Stiper stones, Shropshire. Mr. Salter, in 
Mem. Geol. Surv., vol. iii., p. 337. 
Corresponding specimens were obtained by the anthor in the black 
shales, mentioned in the description of the preceding figure, at Cooks- 
grove, County Meath. 
Fic. 6.—a, b, c. ORTHIS STRIATULA, Conrad, sp. 
O. testudinaria, Hall, Pal. New York, vol. i., pl. xxxii., fig. 1; Mem. Geol. 
Surv., vol: ii., Part L., pl. xxvii., figs. 6-8, and vol. iii, p. 340, pl. xiii., 
figs. 10-14. 
a, b. From the figures in Mem. Geol. Surv., vol. iii., pl. xiii., figs. 11, 12. 
ec. Original. Enlarged view of portion of the surface of a shell, from a slab in 
Mus. Geol. Surv., Ireland. 
Lower Lianpeito.—-[Lord’s Hill, Shelve ?] Sutherlandsbire. 
Uprrr LLANDEILO.—-South Wales. 
CaRraboc ? 
Lower LLANpoverRY.—North of Llandovery, Mem. Geol. Surv., vol. iii., 
p. 340. 
