CHAPTER XVII.

The Cretaceous period--General succession and subdivisions of the Cretaceous rocks in Britain--Cretaceous rocks of North America--Life of the period--Plants--Protozoa--Corals--Echinoderms-- Crustaceans--Polyzoa--Brachiopods--Bivalves--Univalves-- Tetrabranchiate and Dibranchiate Cephalopods--Fishes--Reptiles-- Birds--Literature.