Since the days of Lamanon, other bones of Balæna have been discovered in the soil in different countries, but the study of these fossils has always left something to be desired. In 1806 a fossil Balæna was disinterred at Monte-Pulgnasco by M. Cortesi. Another skeleton, seventy-two feet long, was found on the banks of the river Forth, near Alloa, in Scotland. In 1816 many bones of this animal were discovered in a little valley formed by a brook running into the Chiavana, one of the affluents of the Po. Cuvier has established, among the cetacean fossils, a particular genus, which he designates under the name of _Ziphius_. The animals to which he gave the name, however, are not identical either with the Whales (_Balænæ_), the Cachelots or Sperm Whales, or with the Hyperoodons. They hold, in the order of Cetaceans, the place that the Palæotherium and Anoplotherium occupy among the Pachyderms, or that which the Megatherium and Megalonyx occupy in the order of the Edentates. The _Ziphius_ still lives in the Mediterranean. [Illustration: Fig. 178.--Pecten Jacobæus. (Living species.)] * * * * * The genera of Mollusca, which distinguish this period from all others, are very numerous. They include the Cardium, Panopæa, Pecten (Fig. 178), Fusus, Murex, Cypræa, Voluta, Chenopus, Buccinum, Nassa, and many others. * * * * * The _Pliocene_ series prevails over Norfolk, Suffolk, and Essex, where it is popularly known as the Crag. In Essex it rests directly on the London Clay. Near Norwich it rests on the Chalk. The _Pliocene rocks_ are divided into lower and upper. The _Older Pliocene_ comprises the White or Coralline Crag, including the Red Crag of Suffolk, containing marine shells, of which sixty per cent. are of extinct species. The _Newer Pliocene_ is represented by the Fluvio-marine or Norwich Crag, which last, according to the Rev. Osmond Fisher, is overlaid by Chillesford clay, a very variable and more arctic deposit, often passing suddenly into sands without a trace of clay. The Norfolk Forest Bed rests upon the Chillesford clay, when that is not denuded. A ferruginous bed, rich in mammalian remains, and known as the Elephant bed, overlies the Forest Bed, of which it is considered by the Rev. John Gunn to be an upper division. The Crag, divided into three portions, is a local deposit of limited extent. It consists of variable beds of sand, gravel, and marl; sometimes it is a shelly ferruginous grit, as the Red Crag; at others a soft calcareous rock made up of shells and bryozoa, as the Coralline Crag.