161

FIELD MEETING IN THE PULBOROUGHDISTRICT, SUSSEX.

June 23rd, 1945.

Report by the Director: A. J. Bull

(Weald Research Committee Meeting).

TH~ Pulborough area was last visited by the Association in1935 and 1939 [1*] [2]. The route followed on this latest

visit was planned to combine in one day the best parts of the twoprevious Field Meetings, both from a geological and a scenic aspect.Squadron-Leader J. F. Kirkaldy, who had hoped to act as Director,was unable to return from Germany, so the writer acted in hisstead.

From Pulborough Station the party of 18 followed the mainHorsham-Bogner road and noted that in the road cutting belowthe church the upper part of the Sandgate Beds was composed ofMarehill Clay resting on Pulborough Sandrock.

Turning eastwards, to the bridleway along the crest of theescarpment formed by the Pulborough Sandrock, a fine view ofthe country stretching southward to the South Downs was obtained.Particular features of interest which were pointed out were thegullies in the scarp face of the Downs, the position of the gap cutby the River Arun, and the effects on the landscape of the Greenhurst Anticline and the complementary Wigginholt Syncline, whilstthe opportunity was taken to give an account of the stratigraphyof the Lower Greensand of the area [3].

The main road was regained and followed northwards to Cod­more Hill, where lunch was taken. The roadside cuttings showeddaggers of sandy limestone set in loamy sand belonging either tothe Bargate Beds or the upper part of the Hythe Beds, whichcannot be differentiated on the east side of the River Arun.

From Codmore Hill a road was taken leading westwards alongthe strike, and at Hill Farm exposures were seen in the stonebands near the base of the Hythe Beds. It was seen that these stonebands formed the crest of the escarpment, the lower part of whichwas clay. At Pythingdean, where the road forks northwards,disturbed beds of Hythe stone dipping steeply south and south-westand resting on Weald Clay were pointed out. It was suggestedthat these inclined beds were due to slip down the escarpment andnot to a structural cause, as was suggested long ago by P. I. Martin[4]. The greater height and northward projection of the LowerGreensand escarpment on the western side of the Arun valley as

• For List of References sec p. 162.

162 A. 1. BULL,

compared with its behaviour on the ground already traversed, wasexplained as being partly due to a slight northward increasein thickness of the Hythe Beds [5], but mainly to a considerabledevelopment of chert in the upper part of these beds.

The river was crossed at Pallingham Quay, where the abandonedArun-Wey canal was seen to be built against the face of the lowterrace which bounds the curious trench of the Arun-Rother riversystem [6].

The higher escarpment on the west side of the river consistsof Weald Clay capped by Hythe Beds, and this was ascended bymuddy paths through the woods. On the bridleway through theQuells, going down to Harwoods Green, it was interesting to notethat the path was crossed by outcrops of stone beds apparentlydipping into the hill. These very probably represent old landslips ;such slips are often on an arcuate clay sole, so that as the slippedmass travels downhill, the dip becomes progresisvely steepertowards the hill. After leaving the tongue of Weald Clay atHarwoods Green, pleasant woodland paths were followed up theface of the scarp to the chert beds above Brownshall Farm [I,Plate 15]. Further old workings in the chert beds were passed whentraversing a track leading westwards through the woods. Whenthe road was reached, a tum was made southwards past a good roadsection at Stretch Hill in the loamy lower member of the SandgateBeds. Beyond Fittleworth the magnificent view point of HesworthCommon was ascended. Fortunately visibility was excellent, andthe view of the Rother Valley with its background of the SouthDowns was greatly admired. The Downs could be seen fromButser in the west past Chanctonbury Ring to Wolstonbury inthe east. After some time had been spent in describing anddiscussing the features of the view the party adjoumed to theSwan Hotel at Lower Fittleworth for tea, during which a vote ofthanks to the Director was proposed by Dr. Emily Dix.

After tea pleasant lanes were followed to Stopham Bridge.and several roadside sections in Folkestone Sands were notedwith their characteristic current bedding and ironstone formation.Park Mound was then ascended ; this was the last good view pointto be visited during the day, and in Park Lane the fossiliferousironstone in the middle part of the Sandgate Beds was examined,though unfortunately no ammonite was found.

Pulborough Station was reached in good time for the returntrain.

REFERENCES1. KIRKALDY, J. F. 1935. Field Meeting at Pulborough. Proc. Grot.

Assoc., xlvi, pp. 207-9.2. KIRKALDY, J. F. and A. J. BULL. 1939. Field Meeting at Amberley and

Pulborough. Proc. Geot. Assoc., J, pp. 26-8.

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FIELD MEETING IN THE PULBOROUGH DISTRICT. 163

3. KIRKALDY, J. F. 1937. The Overstep of the Sandgate Beds in EasternWeald. Quart. Journ. Geof. Soc., xciii, pp, 94-126.

4. MARTIN, P. I. 1828. Geological Memoir on a part of Western Sussex.London.

5. KIRKALDY. 1933. The Tectonic Development of the Western Weald inLower Cretaceous Times. Geof. Mag .. lxx, 254-268.

6. KIRKALDY, J. F. and A. J. BULL. 1940. The Geomorphology of the Riversof the Southern Weald. Proc. Geof. Assoc., li, pp, 115-150.

EXPLANATION OF PLATES 13 AND 14PLATE l3.-Looking eastwards across the north end of the gap eroded by the

River Arun in the Lower Greensand above Stopham. The view is fromThe Quells on the west side of the gap; where the escarpment projectsmore to the north than it does on the east side of the river; so that the viewshows the northward facing escarpment, which here has a capping of stonein the lower Hythe Beds, and much of the slope is clay.

Plate 14.-The view from Park Mound eastward over Pulborough. Thechurch stands on the northward facing escarpment formed by the Pul­borough Sand Rock in the upper part of the Sandgate Beds.