HEADON HILL AND ALUM BAY. 149 



bers of an undescribed species of Gypris. The 

 lower part of the cliff consists of sand containing 

 freshwater with marine and estuary shells. 



We next pass Yarmouth, and doubling the 

 headland on which was Worsley's Tower, opposite 

 Hurst Castle, enter Colwell Bay, where the cliffs 

 exhibit alternations of marine and freshwater 

 strata. In the fissure called Bramble Chine a 

 thick bed of oyster shells is exposed, apparently 

 in its original state, the valves being in contact 

 with each other as when living; this appears to 

 be the equivalent of the oyster bed observable at 

 Whitecliff Bay. Many beautiful fossil shells 

 may be collected in this locality. The elegant 

 Cytherea incrassata (PL III. fig. 6), and Neritlna 

 concava (PL II. fig. 5), are found in sandy clay, 

 in as perfect a state as if but recently thrown 

 up by the waves. In Totland, or Tolland's Bay, 

 similar sands, clays, and marls form the cliffs. 



Headon Hill and Alum Bay. — We now 

 approach Headon Hill and the richly coloured 

 vertical strata of Alum Bay. The picturesque 

 character of the dislocated masses of strata forming 

 the face of the cliffs at Headon Hill is shown in 

 PL IX. The appearance of Alum Bay from the 

 sea is imposing in the extreme, and is thus gra- 

 phically described by Sir Henry Englefield : — 



