MIDDLE BALA GROUP. 
51 

Case and 
Column of 
Drawers. 
Reference to McCoy’s 
Synopsis: and Figures of Genera, 
Names and References; Observations, &c. 
Numbers and Localities. 

Gk 
Gk 
Gk 
Gk 
Gk 

Ceraurus Clavifrons, 
Pl. 1 G, fig. 9, p. 154, 

Ceraurus, 
Pl.14, figs. 10, 10 a. 
Zethus atractopyge, 
Pl. 1 G, fig. 1—5, p. 156. 
Zethus, 
Pl. 1 G, fig. 8. 

Encrinurus. 


Cheirurus juvenis, Salter (Mon. Brit. Tril. p. 67, 
1864, pl. 5, figs. 9—12, Mem. Geol. Surv. 11. 
p. 323, pl. 18, figs. 1, 2). Cheir. clavifrons of 
Dalman has been proved distinct, and Ce- 
raurus is an exploded genus of Green. 
N.B. The head or rather glabella is much in- 
flated in this section of the genus, termed 
Actinopeltis by Corda. 
Cheirurus octolobatus, McCoy, sp. (Salter, Mem. 
Geol. Surv. Vol. m1. p. 323, pl. 18, fig. 3. 
Mon. Brit. Tril. pl. 5, figs. 18,14). Ceraurus, 
McCoy, Synopsis, p. 154. 
Cybele verrucosa, Dalm. (Mem. Geol. Surv. 
1866, Vol. 111. p. 324, pl. 19, fig. 7).  Cy- 
bele is an excellent genus established by 
Loven. Zethus is quite a different form, 
Z. verrucosus of Pander and Volborth is 
only a Russian species. Ours is quite com- 
mon in Britain and Sweden. 
Cybele rugosa, Portlock (first figured as Ogygia! 
by Portlock; then described as Cybele by 
Salter in Mem. Geol. Surv. Vol. 1. Pt. 1. 
See Morris, Catal. 1854, p. 103). The spines 
of the tail stream backward so much as to 
reach far beyond the axis. 
Encrinurus sexcostatus, Salter (Mem. Geol. 
Surv. Vol. ru. p. 324, pl. 19, figs. 5, 6, De- 
eade vit. pl. 4, figs. 1—11). Encrinurus has 
no produced spines to the ribs of the tho- 
rax: and generally it is a more compact 
form than Cybele, yet closely allied. Zethus 
is quite distinct from both, and if admitted 
at all (it was founded on a Chetrwrus) can 
only be applied as above. 
Encrinurus multiplicatus, Salter (with many 
side ribs to tail). 
Phacops, Emmrich. The most perfect and 
typical of the whole trilobite family or 
order, with a compact form in the majority 


b. 193, Bala; Cader Din- 
mael; Cefn Grugos, near 
Llanfyllin. 
b. 229, Rhiwlas, N. of 
Bala. 
a. 115, Coniston; Raven- 
stonedale ; Horton; Alt- 
yr-Anker, Meifod. (It was 
one of the earliest trilo- 
bites figured by Dr Llhwyd. 
1698). 
a. 116, Coniston (J. Mar- 
shall, Esq.). 
Bala limestone, Rhiwlas. 
a. 226, Barking, Deut, 
W. Yorkshire. 
