16 GEOLOGY OF THE ISLE OF WIGHT. 



Ft. In. 



Mottled marls - - - ■ - - 28 



Purple marls, with white concretions - - - - 4 



Red marls passing down into white sandstone, with partings 



of marl, current-bedded in large sweeping curves - - 9 



Massive sandstone, bands of bone and sandstone breccia 

 running irregularly through ; 6 to 18 inches of gravel at 

 base, with bones. This bed thins away westwards, and is 

 last seen at Sedmore Point . . - . 



Deep-red and purple marls (at Sedmore Point) 

 Current-bedded sandstone of Sedmore Point - 



Sandown Bay. 



The Wealden formation occupies a mile and a half of coast 

 in this bay, and extends inland for a little over a mile. The axis 

 of the anticline, which has already been described, lies nearly 

 abreast of the stone fort, and trends a little north of west, in a 

 direction parallel to the range of Brading and Berabridge Downs. 

 The southern side of the anticline is entirely concealed by 

 buildings on the cliiF, and by sand on the fore-shore. The first 

 exposure on the northern side is met with at the east end of the 

 o-roins, where mottled clays with bands of sandstone form gentle 

 undidations, with a general tendency to dip to the north-east. A 

 short distance further on the dip increases to 1 1°, and finally to 

 about 20° to the north-east, before the Wealden beds are lost 

 to sight below the Lower Greensand of RedclifF. 



The Wealden series is divisible here as in Brixton Bay into a 

 lower group of variegated clays, and an upper group of fossili- 

 ferous shales. The lower group forms the low cliff or bank which 

 extends as far as Yaverland Fort. It consists of mottled red, 

 purple, and white marls, but is much obscured by slipping. 



The fort stands on a low escarpment formed by a bed of 

 sandstone aliout 8 feet thick ; possibly the same bed that forms 

 the corresponding feature of Barnes High in Brixton Bay, for 

 the base of the blue fossiliferous shales is found at about the same 

 distance below it in the two localities. This sandstone is seen 

 again in the road-side south of Yaverland, and in a sand-pit 300 

 yards south-west of Sandown Farm. There it exceeds 18 feet in 

 thickness, and dips to the south-west at 9°. 



The details of the beds above and below the sandstone in the 

 cliff are as follows : — 



Ft. 

 Fine black shale, Cyprids very abundant. 

 Blue sandy shale, \vith lines of brown grit - - 10 



Sandstone, about - - - ■ - 8 



Blue shale, base not seen - - - - 10 



Blue fossiliferous shales, not well seen, about - - 30 



Purple and mottled marls. 



58 

 The beds above these are much obscured by slips, but can be 

 seen to consist of shales of the usual type of the upper group, 



