4 
(b) Fossil: — 
General 
Cainozoic . . 
Post-Tertiary 
Tertiary 
Cretaceous . . 
Jurassic 
Triassic 
Palaeozoic . . 
Permian 
Carboniferous 
Devonian 
Silurian 
Ordovician . . 
Cambrian . . 
III. Systematic Index = 2231: — 
Am pliine ura .. 
Gastropoda 
Pro3obranchia 
Heteropoda . . 
Opisthobranchia 
Pteropoda . . 
Pulmonata . . 
Scaphopoda .. 
Lamellibrancbia 
Cephalopoda . . 
PAGE 
57 
57 
58 
50 
GO 
G2 
63 
63 
63 
63 
04 
64 
64 
65 
65 
65 
65 
76 
76 
77 
77 
84 
85 
93 
