(Pecten) Neithea Quinquecostata Thetironia (Ammonite) Rhynchonella Minor Mantelliceras Mantelli Parvirostris (Sea Urchins) Micraster Cor-Anguinum Echinocorys Scutatus (Internal cast in flint) LOWER AND UPPER GREENSAND AND CHALK The Chloritic Marl is followed by the Chalk Marl, of much greater thickness. This consists of alternations of chalk with bands of Marl, and contains glauconite and also phosphatic nodules in the lower part. Upwards it merges into the Grey Chalk, a more massive rock, coloured grey from admixture of clayey matter. These form the Lower Chalk, the first of the three divisions into which the Chalk is usually divided. Above this come the Middle and Upper, which together form the White Chalk. They are much purer white than the lower division, which is creamy or grey in colour. The Chalk Marl and Grey Chalk are well seen at the Culver Cliff, and run out in ledges on the shore. The lower part of this division is the most fossiliferous, and contains various species of Ammonities, Turrilites, Nautilus, and other Cephalopoda. (Of Ammonites _Schloenbachia varians_ is characteristic. Also may be named _S. Coupei_, _Mantelliceras mantelli_, _Metacanthoplites rotomagensis_, _Calycoceras naviculare_, the small Ammonoid Scaphites aequalis; and of Pectens, _AEquipecten beaveri_ and _Syncyclonema orbicularis_ may be mentioned). White meandering lines of the sponge _Plocoscyphia labrosa_ are conspicuous in the lower beds. The Chalk Marl is well shown at Gore Cliff, sloping upwards from the flat ledges of the Chloritic Marl. It may be studied well, and fossils found, in the cliff on the Ventnor side of Bonchurch Cove,--which has all slipped down from a higher level. The uppermost strata of the Lower Chalk are known as the Belemnite Marls. They are dark marly bands, in which a Belemnite, _Actinocamax plenus_, is found. The hard bands known as Melbourn Rock and Chalk Rock, which on the mainland mark the top of the Lower and Middle Chalk respectively, are neither of them well marked in the Isle of Wight. In the Middle Chalk _Inoceramus labiatus_, a large bivalve shell, occurs in great profusion; and in the Upper flinty Chalk are sheets of another species, _I. Cuvieri_. It is hardly ever found perfect, the shells being of a fibrous structure, with the fibres at right angles to the surface, and so very fragile.