Wealden District and the Bus Boulonnais. 9 



The western portions of this line and of the Brightling line comprise between 

 them an extensive valley, the formation of which would probably in the first 

 instance be the necessary consequence of the elevation of these lines. Its drainage 

 is somewhat remarkable, the only outlet for its waters being at Robertsbridge, 

 whence they are discharged into the Rother. A comparatively small depression 

 would convert the lower part of this valley into a small bay communicating with 

 the sea by the valley of the Rother. It would seem probable that in the gradual 

 rise of the land it had formerly existed under that form, and that a great part 

 of the denudation, to which its actual form is probably in a great measure due, was 

 thus effected. Its western extremity is bounded by the high land which is con- 

 tinued southward from Frant by Rotherfield to the west of Heathfield Park, the 

 point to which I traced the Brightling anticlinal line. This transverse high land 

 forms a watershed, from the highest points of which the water descends on the 

 one side through the valley just described to be discharged into the sea by the 

 Rother, and on the other to the Ouse, which passes by Lewes and discharges 

 itself at Newhaven. It does not however assume the character of a transverse 

 ridge, its general elevation being much the same as the western extremities of the 

 Brightling, Wadhurst, and Frant Hills on the one hand, and considerably less than 

 that of Crowborough on the other. The Brightling anticlinal line seems to lose 

 all its distinctness when it meets this high land. 



Crowborough Anticlinal Line. — The elevated range including Ashdown Forest on 

 the east and St. Leonards Fol'est on the west manifestly constitutes the central 

 ridge of the middle portion of the Wealden district. It is clearly an anticlinal 

 elevation, though it seems difficult to determine with perfect accuracy the position 

 of the antichnal line. On the northern side of Ashdown Forest there is a gradual 

 but small continuous rise of the beds towards the summit ; and on the south side 1 

 traced a much more rapid and continuous dip to the south from near Crowborough 

 Gate to High Hurst Wood, two miles south of the former place. In considerable 

 quarries at the latter place the dip was about 1 5°. The surface nearer the summit 

 of the Forest is occupied by loose sand, which affords no means of observing the 

 dip. There cannot however be much error in concluding that the anticlinal line 

 passes near to Crowborough Beacon. 



The above observations were made in an excursion from Tunbridge Wells to 

 Crowborough. I also crossed this central elevation from Cuckfield to East Grinsted 

 by Balcombe. The dip at the cutting of the Brighton railroad near the last-men- 

 tioned place was considerable, and to the north, nor could I detect any indications 

 of southerly dip in crossing Tilgate Forest. From this it appeared probable that 

 the position of the anticlinal line was not north of Balcombe, nor can it certainly 

 be far south of that place, as shown by evidence which I shall speak of shortly, 



VOL. Vll. SECOND SERIES. C 



