60 GEOLOGY OF THE ISLE OF WIGHT 



in a pocket, or thickening of the seam of pipe clay, which 

 for forty years yielded specimens abundantly, afterwards 

 thinning out, when the leaves became rare. The leaves 

 lie flat, as they drifted and settled down in a pool. With 

 them are the twigs of a conifer, occasionally a fruit or 

 flower, or the wing case of a beetle. The leaves show a 

 tropical climate. The flora is a local one, differing con- 

 siderably from those of Eocene deposits elsewhere. The 

 plants are nearly all dicotyledons. Of palms there are 

 only a few fragments, while the London clay of Sheppey 

 is rich in palm fruits, and many large palms are found 

 in the Bournemouth leaf beds, corresponding in date to 

 the Bracklesham. The differences may be largely due to 

 conditions of locality and deposition. The Alum Bay 

 flora is characterised by a wealth of leguminous plants, 

 and large leaves of species of fig (Ficus) ; simple laurel 

 and willow-like leaves are common, of which it is difficult 

 to determine the species, and there is abundance of a 

 species of Aralia. The character of the flora resembles 

 most those of Central America and the Malay Archi- 

 pelago. 



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 im- 

 pressions 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, 



