156 GEOLOGY OF THE ISLE OF WIGHT. 



clays, and these abut against a bed of sandy loam, 

 with pebbles and slightly rolled flints, that is in 

 immediate contact with the chalk; as shown in 

 lign. 11, d. The thickness of the eocene strata, 

 from the chalk to the uppermost bed in Headon 

 Hill, is stated by Mr. Prestwich to be 16G0 feet; 

 which is 300 feet less than the series at Wnitecliff. 

 The surface of the chalk in contact with the 

 tertiary beds is much worn, and covered by a layer 

 of sandy loam, containing pebbles, and rolled 

 flints, which are invested with a coating of green 

 earth ; flints of this kind occur, also, at New- 

 haven, and in the fissures and sand-pipes of the 

 Surrey and Sussex downs. Mottled clays and 

 sand, with traces of lignite, as at Whitecliff, next 

 appear, for a thickness of nearly 100 feet ; and then 

 the brown clay, with layers of septaria, abounding 

 in the ditritpa; this is the lowermost bed of the 

 Bognor rocks.* Beds of sandy clay with seams 

 of pebbles, belonging to the same group, succeed, 

 and in some of the layers marine shells are 

 numerous. A fossil crab, common at Sheppey, 



* More than twenty species of shells, and some teeth Of sharks, are enume- 

 rated by Mr. Prestwich, from this group. The most characteristic are 

 hiii a], a pin, in, />, riu nciii us brevirostris, Turritella imbricataria, Pholadomya 



„i,ii-,/iinhii , a, I', nmp, ,u i iili-rnii ilia, and Vrrmi'liia Bognorensit; all well- 

 known Bognor shells, and mentioned in the earliest list of the fossils of that 

 locality. See my " Gi ologj of the South-East of England." 



