﻿3/0 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



fine examples of sinuous pipes and erosive cavities are seen ; and 

 some which resemble dykes of iron-sand are very conspicuous. It is 

 possibly from this iron-ore that the chalybeate spring of Brighton 

 rises near Furze Hill (Wick) ; and the same masses supply much of 

 the brick-earth for the construction of the town. Whether some of 

 these masses belong to the older tertiary age, or all to the drift-epoch 

 under consideration, I do not yet feel assured. 



Extension of the Angular Drift along the South Downs (westward). 

 — For forty miles to the west of Brighton, the surface of the slope of 

 the South Downs is covered with myriads of loose chalk-flints which 

 have been derived from the subjacent rock and especially encumber 

 the north and south depressions. Still further to the south these 

 flints are more fractured and constitute a zone of drifted materials in- 

 cluding many angular flints, which increases largely in width as you 

 travel towards Chichester. From the hills, slopes, and great plain of 

 flint-gravel north of Worthing, through the woodlands and arable land 

 of the Duke of Norfolk's property, and from Arundel to the sides of 

 the Slindon Hills, it directly covers the chalk. Highly ferruginous 

 loam and stiff clay (evidently the remains of the Plastic-clay) usually 

 form the cement in which fragments of angular flint are enveloped. In 

 descending from the bare chalk above Slindon, the detritus is seen to 

 have accumulated partially on the slopes to which some stiff clay is 

 still adherent, and then to have been tumultuously aggregated on the 

 plateau of Slindon Common, where the highly eroded surface of the 

 chalk has been exposed by quarrying out the angular gravel ; exhi- 

 biting much the same appearances as in the railroad-cuttings above 

 the west of Brighton, i. e. with pipes, cavities, and dyke-like vertical 

 bands of drift. 



The drift, in fact, here covers a powerfully eroded low plateau of 

 chalk, on which clay, sand, and angular detritus have been irregularly 

 distributed. 



From the picturesque undulations at Avisford, which form the 

 south edge of this plateau, for two miles on the high road from Arun- 

 del to Chichester, the detritus is exposed on either side of the road, 

 and often in the form of the so-called " Combe Rock " of East Sussex, 

 wholly unstratified, and in thicknesses of 12 to 20 feet, but in which, 

 here and there, as in many other parts of its range, this drift exhibits 

 rude and irregular lamination, and occasionally a sort of oblique lami- 

 nation. Near Westergate it rests on fine sand, but for the most part 

 is associated with stiff clay, both of them resulting from the breaking 

 up of the Tertiary strata. In the gravel-pits at Aldingbourne, the 

 drift, of a deep ochreous red colour, reposes on a highly disturbed and 

 broken surface of Chalk- with-flints. The upper strata of the Chalk 

 exhibit so much contortion and have been so much thrown about and 

 shattered as if by powerful earthquakes, that the geologist can easily 

 picture to himself how a little more force would have broken up and 

 thrown off the imbedded flints into the mass of drift. As in nu- 

 merous other places along the range of the South Downs, the sur- 

 face of the chalk has been sharply broken up and deeply indented ; 

 the cavities being filled up with reddish ferruginous drift. Every- 



