IS 
SILURIAN. 
DEV. 
CARB 
LOWZR. J UPPER. 
Fig. S. 
P. Pd. 
u 
js.]cjp 
Terebratula Family, gen. Terebratula 
Stringocephalus, Reasselaeria 
Other Terebratuloids 
Crania Family, gen. Crania 
Bryozoans 
Acephals 
Lamellibranchs 
Monomyaries 
Dimyaries without a siphon 
Dirayaries having a siphon. 
Cephalates 
Pteropods. . . 
Gastbropods 
Shell without a beak 
Shell beaked 
Cephalopoda 
Nautilus tribe, including Orthoceras, etc. 
Ammonite tribe, gen. Goniatitea. . 
Ammonite tribe, gen. Ammonites 
ARTICULATES. 
Worms 
Crustaceans 
Entomostracans 
Ostracoida 
Trilobitea 
Paradoxides.. 
■ i 
1 i 
Bathyurus . . . 
Asaphua, Remopleurides 
1 
Calymcme, Ampyx, lllamus, Acidas- 
pis, and Ceraurus 
i 1 
■ 
