﻿MURCHTSON FLINT DRIFT OF S.E. ENGLAND. 



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the heaps of those flints, all highly fractured and unrolled, are thus 

 confined to the low hills of the Lower Greensand only, neither ex- 

 tending southwards over the intermediate formations to the hase of 

 the Chalk Hills, nor occurring on the higher ridges of the same for- 

 mation in North Heath, Holder Hill, and the hills of Petworth. The 

 mass of flint-debris in the south-western part of the Wealden denu- 

 dation has thus a width varying from one to two and a half miles, 

 and is presumed to have proceeded from the west. The same phse- 

 nomena described near Petersfield are seen near Pulborough, where 

 the ferruginous or Upper member of the Lower Greensand has been 

 deeply eroded, and the flint-debris lodged in its cavities on the sum- 

 mit of Fittleworth Hill, as well as in the synclinal slopes of the Gault 

 of Trip Hill— points to which Mr, Martin directed my notice*. 



In the environs of Pulborough, the numerous anticlinal and synclinal 

 flexures into which the strata have been thrown, as well described by 

 Mr. Martin, tend naturally to explain why a great amount of debris 

 (particularly of the Lower Greensand) should there be found. The 

 local and unrolled character of such surface-accumulations will also 

 presently be well accounted for by reference to other ruptures of the 

 Chalk. It will also soon be made manifest, that the chief debris ac- 

 cumulated between the central dome of the Weald and the Chalk 

 escarpments, is of the same age as that which is seen at intervals on 

 the sides of the transverse valleys in the Chalk and is spread in such 

 vast quantities over the external slopes of the South Downs. 



Anticlinal in the South Downs. — An anticlinal which Mr. Martin 

 has traced from near Midhurst on the west to the Chalk-range east 

 and south-east of Lewes must be taken into consideration in explain- 

 ing the denudation of the depressions along which it passes, and in 

 accounting for additional heaps of detritus which have been thrown 

 to the right and left of it. Such signs of shedding of the debris of 

 the Lower Greensand to the north and south of this line of rupture 

 are well seen to the south-west, south, and south-east of Pulborough ; 

 and the result is, that in this district the debris of the western drift 



grey, and white chalk regularly overlying the Upper Greensand in this very narrow 

 north and south counterfort of about three-quarters of a mile in length, and from 

 which the Chalk with flints has been entirely removed. I confess that the synclinal 

 form of this narrow mass of chalk (which is separated from the main escarpment 

 by a deep notch) once impressed me with the idea that it was a remnant or spur 

 of the formation which had resulted from a transverse movement of oscillation, 

 which failing to produce a cross rent or valley had left a north and south ridge as 

 a memento of the force employed. The slightly broken condition, however, of 

 the strata and the other facts previously alluded to compelled me to abandon 

 that hypothesis, the more readily as there is no trainee of flints extending from 

 Tarbury across the plateau of Malm Rock and valley of Gault to the sand-hills 

 of West Heath, &c. See fig- 3, and Geological Map of parts of Hants and Sussex, 

 Trans. Geol. Soc. Lond. loc. cit. 



* Near Pulborough, although the chalk-escarpments are quite free from the flints, 

 Mr. Martin assures me that they occur with some drift-loam, and a few flints in 

 patches, on the Upper Greensand and Chalk Marl. This is a highly dislocated 

 tract. In all the western tracts, the occurrence of a few scattered flints on the 

 mere soil of the Malm Rock and Gault is a rare occurrence, and in no instance do 

 they enter into erosions of those rocks or form heaps of drift. 



