The Bracklesham beds are followed by the Barton clay, famous for the number of beautiful fossil shells found at Barton on the Hampshire coast. At Whitecliff Bay the fossils are, unfortunately, very friable. At Alum Bay the pathway to the shore is in a gully in the upper part of the Barton clay. The strata consist of clays, sands, and sandy clays. The base of the beds is marked by the zone of _Nummulites elegans_. Numerous very pretty shells of the smaller Barton types may be found, with fragments of larger ones; or a whole one may be found. Owing to the cliff section cutting straight across the strata, which are nearly vertical, there is far less of the beds open to observation than at Barton, which probably accounts for the list of fossils being much smaller. The shells are chiefly several species of _Pleurotoma_, _Rostellaria_, _Fusus_, _Voluta_, _Turritella_, _Natica_, a small bivalve _Corbula pisum_, a tubular shell of a sand-boring mollusc _Dentalium_, _Ostroea_, _Pecten_, _Cardium_, _Crassatella_. The fauna is like a blending of Malayan and New Zealand forms of marine life. Throughout the Eocene from the London clay onward the shells are such as abound in the warm sea south east of Asia. Similarly the plant remains take us into a tropic land, where fan palms and feather palms overshadowed the country, trees of the tropics mingling with trees we still find in more Northern latitudes. The general character of the flora as of the shells was Oriental and Malayan; both being succeeded in later strata by a flora and fauna with greater analogy to that now existing in Western North America. In Alum Bay the Barton clay is suddenly succeeded by the very fine yellow and white sands which run along the western base of Headon Hill, the curve of the syncline bringing them round from a nearly vertical to an almost horizontal position. These are now known as the Barton Sand. They are 90 ft. thick, the whole of the Barton beds being 338 ft. in Alum Bay, 368 ft. in Whitecliff. The sands were formerly extensively used for glass making. They are almost unfossiliferous. The passage from Barton clay to the sands in Whitecliff Bay is more gradual. The sands here show some fine colouring which reminds us of the more celebrated sands of Alum Bay. [Footnote 11: See Memoir of Geological Survey of I. W. by H. J. Osborne White, F.G.S. 1921, p. 90.] Chapter IX THE OLIGOCENE We pass on to strata which used to be called Upper Eocene, but are now generally classified as a period by themselves, and called the Oligocene. They are also known as the Fluvio-marine series. Large part was deposited in freshwater by rivers running into lagoons, or in the brackish water of estuaries, while at times the sea encroached, and beds of marine origin were laid down.