46 GEOLOGY OF THE ISLE OF WIGHT 



in the Isle of Wight. In the Middle Chalk Inoceramus 

 labiatus, a large bivalve shell, occurs in great profusion ; 

 and in the Upper flinty Chalk are sheets of another species, 

 7. Cuvicri. It is hardly ever found perfect, the shells 

 being of a fibrous structure, with the fibres at right angles 

 to the surface, and so very fragile. 



There is a striking difference between the Middle and 

 Upper Chalk, which all will observe. It consists in the 

 numerous bands of dark flints which run through the 

 Upper Chalk parallel to the strata. The Lower Chalk is 

 entirely, and the Middle Chalk nearly, devoid of flint. 

 Though the line at which the commencement of the Upper 

 Chalk is taken is rather below the first flint band of the 

 Upper Chalk, and a few flints occur in the highest beds 

 of the Middle Chalk ; yet, speaking generally, the great 

 distinction between the Middle and Upper Chalk, the 

 two divisions of the White Chalk, may be considered to 

 be that of flintless chalk and chalk with flints. 



Early in our studies we noticed the great curves into 

 which the upheaved strata have been thrown, and that 

 on the northern side of the anticline the strata are in 

 places vertical. This can be well observed in the Culver 

 Cliffs and Brading Down, where the strata of the Upper 

 Chalk are marked by the lines of black flints. In the 

 large quarry on Brading Down the vertical lines of flint 

 can be clearly seen ; and by walking at low tide at White- 

 cliff Bay round the corner of the cliff, or by observing the 

 cliff from a boat, we may see a beautiful section of the 

 flinty chalk, the lines of black flints sloping at a high 

 angle. The flints in general form round or oval masses, 

 but of irregular shape with many projections, and the 

 masses lie in regular bands parallel to the stratification. 

 The tremendous earth movement which has bent the 

 strata into a great curve has compressed the vertical 

 portion into about half its original thickness, and has 

 made the chalk f our downs extremely hard. It has 



