UPPER CAMBRIAN. 

Reference to McCoy’s 
Synopsis: and Figures of Genera. 
Names and References; Observations, &c. 

part only. 
p. 128, 
p. 129. 

Worm tubes and tracks, 
Pl. 18, £13, p. 10. 
Serpulites dispar, p. 132 in 
p. 129. 
ECHINODERMATA. 
Crinoid, and probably Cystidean fragments, 
but of unknown species and genera, are 
common in the limestone of Craig-y-Glyn 
and Craig-y-Beri, Llanrhaiadr. 
ANNELIDA. 
Pyritonema fasciculus, McCoy. The analogy 
between this bundle of tubes and the 
skeleton of the glass plant polype is very 
close. But the real affinity is most probably 
with the straight-tubed gregarious Serpule, 
such as are found in the carboniferous rocks, 
Serpula parallela for instance. In proof of 
this there occurs another species, which has 
the tubes separate. 

Pyritonema , sp. Loose tubes in green- 
ish voleanic grit. 
N.B. The following 4 species are in all lists 
included in the Lower Bala or Llandeilo 
flag, but it is quite probable they are of 
Middle Bala age. 
Nemertites Olivantii, McLeay (Sil. Syst. pl. 27, 
fig. 4), Superficial trails of long worms 
(Helminthites ?). 
Myrianites McLeayii, Murchison (Sil. Syst. 
pl. 27, fig. 3). Impression of the trail of 
a rather long worm, in zigzag folds. At one 
end we seem to have the impression of the 
animal itself, with its lateral feet or bundles 
of sete. 
Nereites Sedgwickii, McLeay. Sil. Syst. pl. 27, 
fig. 2. The large foliaceous gill-plates and 
cirrhi are strongly shewn in this imprint. 
It is the original figured specimen. 

Numbers and Localities. 
a. 70, Craig-y-Glyn, Llan- 
rhaiadr. 
a. 73, Tregib, Llandeilo. 
[This is the specimen on 
which was founded the 
supposed fish-defence from 
the Llandeilo flag, The 
resemblance is very great 
at first, but I had no excuse 
for the blunder, which mis- 
led others. J. W.S,] 
Tan-y-craig, N. of Builth. 
a. 76. Also in Shale, at 
Tre-coed, 3m. N. of Builth. 
a. 72, Llampeter, S. Wales. 
a. 75, Llampeter. 
a. 74, Llampeter. [N.B. 
This species also occurs at 
Aberystwith, in Middle 
Bala rocks.] 
