96 GEOLOGY OF THE ISLE OF WIGHT 



extends north a few yards beyond the chalk marl on to 

 Lower Greensand. It has been formed by raimvash from 

 a hill of chalk, which must once have existed to the south. 

 The deposit contains numerous existing land-shells, 

 especially Helix nemoralis and other species of Helix. 



Between Atherfield and Chale at the top of the cliff is 

 a large area of Blown Sand. The sand is blown up from 

 the face of the cliff below. It reaches a thickness of 20 

 feet, and possibly more in places, and forms a line of 

 sand dunes along the edge of the cliff. The upper part of 

 Ladder Chine shows an interesting example of wind- 

 erosion. The sand driven round it by the wind has worn 

 it into a semi-circular hollow like a Roman theatre. 



Small spits, consisting partly of blown sand, extend 

 opposite the mouths of the Western Yar, the Newtown 

 river, and the most extensive at the mouth of the old 

 Brading Harbour, separating the present reduced Bern- 

 bridge Harbour from the sea. This is called St. Helen's 

 Spit, or " Dover," the local name for these sand spits. 



