Crinoids 
(Sea-lilies). 
An Ammonoid 
(Euomphalus). 
Rugose corals. 
Brittle star. 
Graptolites. 
Trilobites. 
Sea-scorpion 
(Pterygotus). 
Sea-weeds 
(Bulhotrephii 
Sea-scorpion 
(Stylonurus). 
Sponge. 
Sea-urchin. 
King-crab 
(llemiaspis). 
Tabulate corals 
SILURIAN PERIOD. 
To face page 15. 
