68 GEOLOGY OF THE ISLE OF WIGHT 



of marls, in which many interesting fossils have been 

 found. They cover a large area of the northern part of 

 the Island, largely overlaid by gravels, and are only seen 

 on the coast at Hamstead, where they form the greater 

 part of the cliff, which reaches a height of 210 ft., the top 

 being capped by gravel. In winter the clays become 

 semi-liquid, in summer the surface may be largely slip 

 and rainwash, baked hard by the sun. The lower part 

 of the strata may be best seen on the shore. The strata 

 consist of 225 ft. of freshwater, estuarine, and lagoon 

 beds, with Unio, Cyrena, Cyclas, Paludina, Hydrobia, 

 Melania, Planorbis, Cerithium (rare), and remains of 

 turtles, crocodiles, and mammals, leaves and seeds of 

 plants ; and above these beds 31 feet of marine beds with 

 Corbula, Cytherea, Ostrea callifera, Cuma, Valuta, Natica, 

 Cerithium, and Melania. 



Except for the convenience of dividing so large a mass 

 of strata, it would not be necessary to divide these from 

 the Bembridge beds, as no break in the character of the 

 life of the period occurs at the junction. The basement 

 bed of the Hamstead strata is known as the Black Band, 

 2 feet of clay, coloured black with vegetable matter, with 

 Paludina lenta very numerous, Melanopsis carinata, 

 Limnaa, Planorbis, a small Cyclas (C. Bristovii), seed 

 vessels, and lumps of lignite. It rests on dark green marls 

 with Paludina lenta and Melanopsis, and full of roots. 

 This evidently marks an old land surface. About 65 feet 

 higher is the White Band, a white and green clay full 

 of shells, mostly broken. There are bands of tabular 

 ironstone containing Paludina lenta. Clay ironstone was 

 formerly collected on the shore between Yarmouth and 

 Hamstead and sent to Swansea to be smelted. The 

 strata consist largely of mottled green and red clays, 

 probably deposited in brackish lagoons. These yield 

 few fossils except remains of turtle and crocodile and drifted 

 plants. The blue clays are much more fossiliferous. 

 Among other plants are leaves of palm and water-lily. 



