
MIDDLE BALA GROUP. 
63 


C. d , 
Colunnat Reference to McCoy's Names and References; Observations, &c. Numbers and Localities. 
Drawers. | Synopsis: and Figures of Genera. 
Gm Stroph. compressa, p. 242. | Strophomena expansa, Sow. (Siluria, 2nd ed. | Llanfyllin; Meifod; Weleh- 
pl. 6, fig. 4). The remarkable striated fan- pool; Bala; Penmachno; 
shaped muscle scars easily distinguish this Pwllheli, and all through 
finely striated species. the Snowdon district and 
Shropshire. 
Strophomena tenuistriata, Sow. (Siluria, 2nd Alt-yr-Anker, Meifod. 
ed. pl. 5, fig. 15). 
Gm Lept. deltoidea, McCoy. Strophomena bipartita, Salter (Quart. Journ. | b, 246, Acton Scott. 
| 
| Pl. 1H. figs. 88335, p. 246. 

p. 244. 
S. grandis, p. 245. 
p. 240. 



Geol. Soc. Vol. 10, p. 74). Must be distin- 
guished by its strong central rib and flatter 
form from 8. deltoidea. 
Strophomena simulans, McCoy. Rather adoubt- 
ful fossil. 
Strophomena grandis, Sow. (Siluria, 2nd ed. 
pl. 6, figs. 6, 7). Our largest Cambrian 
Strophomena, with minute teeth, a very thin 
striated shell. 
Strophomena, sp. (coarser strix than S. grandis). 
Strophomena pecten, Linn. (Davidson, Introd. 
Brach. Pal. Mon. pl. 8, figs. 163, 164). 
_Strophomena funiculata, Orthis, McCoy (Sil. 
Foss. Ireland, p. 30, t. 3, fig. 11). 
Leptena, Dalman. Composed of those thin 
(usually transverse) Brachiopods which have 
the one valve involute on the other. 
| Leptena transversalis, Dalm. (Siluria, 2nd ed. 
pl. 9, fig. 17). Differs from LZ. sericea in 
the strong internal muscles which are longer, 
and also in the very spinose inside, the spines 
leaving deep pits on the cast. 

b. 250, Blaen - y - ewm, 
Nantyr; b. 249, Cefn Goch, 
Glyn Ceiriog. b. 251, Gol- 
den Grove? wholly doubt- 
ful, both species and local- 
ity. 
b. 256, Horderley; Bodean, 
Pwllheli. 
b. 255*, Cefn Goch, Glyn 
Ceiriog; b. 256*, Raven- 
stonedale; Cefn Coedog, 
near Corwen. 
Coniston; Applethwaite 
Common; Ravenstonedale; 
Horton; Blaen - y - Cwm, 
Nantyr, Glyn Ceiriog. 
Cyrn-y-Brain? Llandovery 
rock. 
Range— Upper Cambrian 
—Silurian. 
b. 255, Coniston; above Ro- 
ther Bridge; Llansant- 
fraid, Glyn Ceiriog. 
