EXPLANATION OF THE PLATES. 15 
ECHINODERMATA.— CRINOIDEA. 
Fia. 5.—a, b. CYATHOCRINUS, species undetermined. 
Mr. Salter, in Memoirs Geological Survey, vol. iii., p. 284, pl. xi. B., 
fig. 9. 
a. Portion of stem, natural size. 
b. The same, enlarged. 
The figures above are reproduced here, as it is believed to bethe oldest Crinoid 
known in the British rocks, and is stated by Mr. Salter to be clearly distinct 
from Glyptocrinus, the Caradoc fossil. 
Lower LLANDEILO.— West of Stiper stones, Shropshire. 
ANNELIDA. 
Fic. 6.—NEREITES CAMBRENSIS, Murchison. 
Reduced from the original figure in the Silurian System, 1839, vol. ii., p. 700, 
pl. xxvit., fig. 1. , 
Locality.—Llandeilo, Lampeter, Caermarthenshire, South Wales. 
Fic. 7.—ARENICOLITES LINEARIS, Hail (Scolithus), Salter. 
From the original figure in Memoirs Geological Survey, vol. iii., p. 292, pl. 
_ x, B., fig. 27, representing small tubular burrows of nearly correspond- 
ing size in a sandy rock. 
Lower Luanpr110 or Urrer Tremapoc.—Stiper stones, Shropshire. 
Fia. 8.—Scouires, Salter. 
Annelide tracks or burrows ; reduced one-third, from the original figure in 
Memoirs Geological Survey, vol. iii., p. 292. 
‘‘ The ordinary fillings up of worm tracks in the sandy mud, common in all 
Lower Silurian rocks.” 
Hard Sandstones at the base of Lower LuANDEILO Shales above Penmorfs, 
near Tremadoc. 
