12 Mr, Hopkins on the Structure of the 



inclination of the strata ; while farther westward the elevation of Ashdown Forest 

 has given a considerable and continuous declination of the strata to the south, with 

 which the surface of the country is there in accordance. The actual drainage of 

 the south side of the central ridge from Rotherfield to St. Leonards Forest appears 

 to have originated in this continuous descent of the beds from Ashdown, by which 

 an opening was afforded to the water from the western part of the range, while the 

 Cuckfield antichnal ridge presented a barrier to their southerly progress. Finally, 

 the configuration of the surface between the ridge just mentioned and the central 

 one is manifestly due to the internal structure, with which also the general descent 

 of the surface to the south from the Cuckfield ridge is in perfect accordance. 



Frant Line. — About three miles north of the Wadhurst anticlinal line is a range 

 of hill, extending from Etheridge Park on the west, by Frant, nearly to Lamber- 

 hurst on the east. In ascending the hill from Tunbridge Wells by Frant, the dip 

 is small but distinctly to the south, and therefore opposite to the general dip on 

 this side the central range. A new cut in the great road also immediately south 

 of Lamberhurst exhibits the section of an anticlinal line with rapid dips. These 

 observations have convinced me that this range (which forms a marked feature in 

 the country) originated in a curvature of the strata, but such that the deviation 

 from horizontality had not been very considerable, except near Lamberhurst. The 

 prominent feature which the range presents to the north, is probably more due to 

 the denudation of the valley below than to the elevation of the hill. Still both 

 analogy and direct evidence (as far as it extends) indicate the origin I have assigned 

 to it. It will be observed that it preserves an exact parallelism with the Wad- 

 hurst line. All traces of it appear to be lost in the transverse high land already 

 mentioned as passing by Frant and Rotherfield. 



Bidborough Hill. — This hill is about three miles south of Tunbridge. The road 

 from that place to Tunbridge Wells affords a good section, exhibiting the upper 

 beds of the Hastings sand rising rapidly from beneath the Weald clay, which 

 approaches the foot of the hill on the north side. There must necessarily be an 

 exactly similar rise of the beds along the north side of the hill further to the west, 

 since the beds of the Hastings sand on the side and summit of the ridge rise 

 much above the level of the upper surface of the Weald clay in the valley. On 

 the south side of the hill I could make no good observations of the dip except near 

 Southborough, where the beds are nearly horizontal. More westward there were 

 indications of a considerable dip to the south, which seems probable also from the 

 external form of the hill. I cannot however assert such to be the case from good 

 observations. The western extremity of the hill is bounded by the transverse 

 valley of the Medway ; the Tunbridge road passes over its eastern extremity. 

 This may be considered as a line of flexure rather than an anticlinal hne. 



