454 



MR. J. V. ELSDEN ON THE 



[Aug. 1909, 



unlike the sharp uniclinal extending from Purbeck through the Isle 

 of Wight, and now shown to exist at Seaford Head. Even the 



Greenhurst anticline, a 

 considerable fold ex- 

 tending for several miles, 

 is quite a symmetrical 

 undulation. It seems 

 to be clear, therefore, 

 that the Seaford fold 

 belongs to the Purbeck — 

 Isle of Wight system, 

 which, as is known, 

 consists of a series of 

 uniclinal flexures ar - 

 ranged in echelon, each 

 with a steep face towards 

 the north. 



It is possible also to 

 suggest a reason why 

 the Seaford fold should 

 come to a sudden termi- 

 nation in a fault in the 

 Cuckmere Valley. Mr. 

 Clement Eeid has shown 

 that at Eastbourne there 

 is a strong transverse 

 fold, running north - 

 eastwards below Beachy 

 Head, 1 with a steep 

 westerly face, and affect- 

 ing the strike of the 

 beds in this locality. 2 

 This implies an easterly 

 thrust which would 

 tend to counteract and 

 neutralize the southerly 

 thrust to which the 

 Purbeck — Isle of Wight 

 folds were due. The 

 complex strain thus 

 set up may have found 

 relief in the production 

 of the Cuckmere Eault. 



3 'Geology of the Country around Eastbourne' Mem. Geol. Surr. 1898 

 (Expl. of Sheet 334) p. 11. 



2 Topley erroneously interpreted this somewhat complicated structure as 

 two folds parallel to the main Wealden axis. One of these, the Holywell 

 syncline, he thought might possiblvbe continued through Seaford to Newhaven. 

 See ' Geology of the Weald ' Mem. Geol. Surv. 1875, p. 229. 



