38 GEOLOGY OF THE ISLE OE WIGHT. 



Ft. In. 





f Reddish clay, becoming pale-blue below, very fos- 

 j siliferous in the lower part - - 



., . I Soft yellow sandstone, with a few fossils - 

 ^' S J Pale-red clay, bluish in parts, a few fossils 

 G "^ I Four bands of very hard grey sandstone ; nc fossils 

 2 '^ i Ked clay, a few fossils in the lower part 

 ^ 'i]^ ^ TDark-green sand, with small pebbles 



and grit, many fossils - - 1 



p 11 1 J Pale-blue sandy clay with many small 

 Ferna lied <; pg^ji^^gg (rolled bivalves, Ammonites, 

 I &c.), and larger pebbles of sandstone, 

 j_ wood, &c., at base ; many fossils - 2 

 Wealden Shales {see p. .9). 



198 5 



The lumps of Carstone contain many pebbles, up to half an 

 inch in length. Its thinness is in accordance with what has been 

 indicated in the Isle of Wight, where it thins from about 70 feet 

 at Sandown to 30 feet near Bonchurch, to 12 feet near Blackgang, 

 and to 6 feet in Compton Bay. 



The Sand-rock Series is not easily distinguished unless the 

 dark clay with selenite, 15 feet thick, be taken as the represen- 

 tative of the thick clay of Blackgang Chine (35-40 feet thick). 

 A laro-e part of the Ferruginous Sands has assumed a character 

 which in the eastern part of the Isle of Wight is seen only in 

 the Sand-rock Series, namely, that of interlaminated white sand 

 and blue clay (the " foliated sands and clays " of Fitton). In 

 Compton Bay this change is foreshadowed by the appearance of 

 thin beds of this type, interstratified with ferruginous sands, 

 considerably below tlie base of the Sand-rock Series. 



The very fossiliferous limestone, 10 inches thick, corresponds 

 in position 'with the Crackers, the most fossiliferous zone in the 

 Atherfield section. 



The Atherfield Clay presents no unusual features, except that 

 there are beds of sandstone at two horizons in it. The recog- 

 nition of the Perna Bed, and of the usual sharply defined line 

 dividing it from the Wealden Shales, was a satisfactory point. 

 The rolled phosphatic pebbles in tlie Perna Bed are slightly 

 laro-er and more abundant at Puntield than in the Isle of Wight, 

 and more frequently recognisable as the casts of bivalves and 

 Ammonites. This, as well as the changes in the overlying beds, 

 indicates that in working westwards we aj)proach the old shore 

 line of the Lower Greensand sea. 



The fossils in the foUoM-ing list, except where otherwise noted, 

 w^ere collected for the Survey by John Rhodes, and have been 

 identified by Messrs. G. Siiarman and E. T. Newton. The 

 specimens marked thus * arc inserted on the strength of their 

 having been recorded from the " Marine Bands of Punfield" by 

 Prof. .Tudd in the Qvdrt. Journ. Gcol. Soc, vol. xxvii. p. 215. 

 Those marked t are added on the authority of Mr. Meyer, ibid., 

 vol. xxviii. p. 252 and vol. xxix. p. 73. 



