82t GEOLOGY OF THE ISLE OF WIGHT. 



where a fine spring issues from its junction with the Chalk 



T^arl 



At Punfield, the Ohloritic Marl is 3 feet 6 inches thick 

 and contains phosphatic casts of Ammonites, Nautilus, and an 

 Exogyra which seems indigenous. The Chert Beds below it, in 

 which the chert occurs only as cherty lumps, contain Exogyra 

 conica in great abundance, with Siphonia tulipa, Zittel, Pecten 

 asper, Lamk, P. orbicularis, Sow., P. quinquecostatus, Sow., 

 Pleiirotomaria, and Ammonites varians, Sow. 



Upper, Middle, and Lower Chalk. 



1. Gompton Boy, along the Central Dotons, to Culver Clirff. 



In proceeding westwards from the Needles along the coast, we 

 find the Middle Chalk first coming in at the foot of the cliff at 

 Oldpepper Rock, 700 yards east of Sun Corner. Up to this 

 point the cliff, which is over 400 feet in height, is vertical and 

 descends sheer into the sea, but, where the Middle Chalk rises from 

 beneath the water, is fringed with a rough beach of fallen blocks. 

 Oldpej^per Rock is an outstanding mass of Middle Chalk, still 

 in situ. After 500 yards the top of the Middle Chalk descends 

 ao-ain beneath the sea, and the cliff becomes once more vertical. 

 At a point 800 yards west of the Beacon (or about IJ mile east 

 of Sun Corner), known as New Ditch Point, the Middle Chalk 

 rises again into the cliff, and so continues for a little over a mile, 

 when it once more sinks below the sea. The same change in the 

 character of the cliff is observable here also, and the vertical walls 

 of chalk and remarkably picturesque range of caves are con- 

 veniently situated for examination. The Middle Chalk rises 

 finally about 600 yards east of the easternmost point of Fresh- 

 water Bay. Thence it slants gradually up the cliff to^ a cutting 

 in the Military Road on Afton Down, where the following section 

 occurs : — 



Military Road Cutting, Afton Down. 



Ft. In. 



" Chalk with flints - - . - 



Nodular chalk, without flints - - 6 



Marl - - . - - - 1-2 



rx r^ 11 J Nodular chalk, without flints - - 8 



Upper Chalk I .^.^g g^^^y ^^j.1 - - - - 1-2 



Nodular chalk - - - - 6 



I Nodule Bed (Chalk-rock), green-coated no- 

 1^ dules in the top 3-6 inches - - 1 6 



Middle Chalk - Massive chalk, weathering into small frag- 

 ments, but not nodular, with bands of marl 

 at 4-10 feet intervals. Pyrites and Tere- 

 bratula semiglobosa - - - 60 0+ 



The Lower Chalk first rises from beneath the sea, at a point on 

 the beach nearly midway between the easternmost point of Fresh- 

 water Bay and the path down the cliff on the outcrop of the 



