CHAP. X.] CRETACEOUS PERIOD. 167 



at Pimfield on the Dorset coast, where the beds include 

 layers of lignite and shales with Cyrena. In this direction, 

 too, the whole group thins out rapidly, and is not more 

 than 100 feet thick at Worbarrow Bay. 



The Yectian beds seem, indeed, to have their maximum 

 thickness (800 feet) below Hampshire, for at the west end 

 of the Wealden area, near G-odalming and Petersfield, the 

 whole group is not more than 450 feet thick, and it con- 

 tinues to diminish eastward, being about 320 feet at Seven- 

 oaks, 250 at Sandgate and Folkestone, and only 31 be- 

 neath Dover. The same diminution can be traced along 

 the foot of the South Downs, its thickness at Eastbourne 

 being only 70 feet, and in each case it is the highest beds 

 which remain ; the same is the case at Chatham, where a 

 boring has proved 41 feet of the upper sands resting on 

 Oxford Clay. 



It is clear, therefore, that the Vectian beds of the Weald 

 thin to north-east, east, and south-east ; that they should 

 thin east and north-east is not surprising, for we know 

 that land lay in that direction, but that they thin to the 

 south-east is important as showing that the water was 

 shallow near Eastbourne, and therefore that part of the 

 southern shore-line was probably not far off that place. 



How far the Atherfield Clay and Walpen Sands extend 

 through the north of Hampshire has not yet been ascer- 

 tained, but they probably thin out northward and westward 

 in the same way as they do northward and eastward in 

 Kent, for when the Vectian emerges from beneath the 

 G-ault in Wiltshire only the representative of the Shanklin 

 Sands remains. In Wilts and Berks this upper member 

 consists of brown ferruginous sands, with occasional, beds 

 of conglomerate, which contain a curious mixture of pebbles 

 rounded pebbles of quartz, banded slate, and cherty lime- 

 stone, similar to those which occur in the Portland Beds, 

 and which may have been derived from the destruction of 



