The Bracklesham Beds in Alum Bay (570 ft. thick) consist of clays, with lignite forming bands 6 in. to 2 ft. thick; white, yellow, and crimson sands; and in the upper part dark sandy clays, with bands showing impressions of marine fossils. Alum Bay takes its name from the alum formerly manufactured from the Tertiary clays. The coloured sands have made the bay famous. The colours of the sands when freshly exposed, and of the cliffs when wet with rain, are very rich and beautiful,--deep purple, crimson, yellow, white, and grey. Some of the beds are finely striped in different shades by current bedding. The contrast of these coloured cliffs with the White Chalk, weathered to a soft grey, of the other half of the bay is very striking and beautiful. About 45 ft. from the top is a conglomerate of flint pebbles, some of large size, cemented by iron oxide. In Whitecliff Bay the Bracklesham Beds (585 ft.) consist of clays, sands, and sandy clays, mostly dark, greenish and blue in colour, containing marine fossils and lignite. Sir Richard Worsley, in his History of the Isle of Wight, tells that in February, 1773, a bed of coal was laid bare in Whitecliff Bay, causing great excitement in the neighbourhood. People flocked to the shore for coal, but it proved worthless as fuel. It has, however, been worked to some extent in later years. In some of the beds are many fossils. Numbers have lately been visible where a large founder has taken place. There are large shells of _Cardita planicosta_ and _Turritella imbricataria_. They are, however, very fragile. In a stratum just above these are numbers of a large Nummulite (_Nummulites laevigatus_). These are round flat shells like coins,--hence the name (Lat. _nummus_, a coin). They are a large species of foraminifera. We may split them with a penknife; and then we see a pretty spiral of tiny chambers. A smaller variety, _N. variolarius_, occurs a little further on, and a tiny kind, _N. elegans_, in the Barton clay. One of the most striking features of the later Eocene is the immense development of Nummulite limestones--vast beds built up of the delicate chambered shells of Nummulites,--which extend from the Alps and Carpathians into Thibet, and from Morocco, Algeria, and Egypt, through Afghanistan and the Himalaya to China. The pyramids of Egypt are built of this limestone.