ECONOMIC GEOLOGY. 253 



100-00 

 Specific Gravity, 2-71. 



The specimen showed crystals of wavellite and iron pyrites 

 here and there. 



The fossil remains of animals also in these beds have been found 

 by Messrs. Paine and Way (op. cit., p. 84) to be very rich in 

 phosphoric acid. Among these may be particularized the blocks 

 of fossils in the Scaphite, the Lower Crioceras, and the Second 

 Gryphtea beds ; besides the casts of Ammonites and Scaphites 

 which lie upon the beach. Some nodular masses of shells of a 

 dark iron colour in the cliffs near Shaidiliii are stated by Mr. 

 Nesbit to contain phosphoric acid to the extent of at least 15 per 

 cent. The whole of the substances examined contained likewise 

 organic matter and fluorine, at times in large quantities.^ 



In the upper part of the Lower Greensand, at Pedcliff near 

 Sandown, there occurs the band referred to as the '^ Coprolite 

 Bed " (p. 37), and as was pointed out, phosphatic nodules occur 

 at about the same horizon in Compton Bay. The nodules in the 

 " Coprolite Bed " are probably richer in phosphate than any others 

 in the Island. They are of a brown or yellow colour and about 

 ^ to I inch in diameter. The band in which they occur, however, 

 is only 4 inches thick. It rises from beneath the beach about 160 

 yards from the centre of the gully formed by the Gault. Those 

 in the Compton Bay section are small and few and far between. 



The Upper Greensand. 



The only attempts hitherto made in the Isle of Wight to extract 

 phosphatic nodules, were commenced in the Chloritic Marl, on 

 St. Catherine's Down. The nodules are of a pale brown colour, 

 friable, and of rather a low specific gravity. They are scattered 

 through about three feet of sand, and are nearly all casts of shells, 

 principally Ammonites varians. The workings, which seem to 

 have been soon abandoned, were commenced about the year 1851 

 on the brow of Gore Cliff at the north end of the outlier of chalk. 

 The following analyses by Mr. J. C. Nesbit are quoted from 

 the Notes on the Geology and Chemical Constitution of the various 

 Strata in the Isle of Wight by Captain Ibbetson, p. 36. 



* Quart. Journ. Geol. Soc, vol. iv. p. 262. (1848.) 



