10 Mr. Hopkins on the Structure of the 



Of the position of this line between Crowborough Beacon and Balcombe, I have no 

 evidence, but the general continuity of the Hne between these points is rendered 

 almost certain by the general structure of this part of the district. We may con- 

 clude therefore that it here runs almost exactly east and west, and we observe that 

 if it be continued easterly, it precisely coincides with the Wadhurst Une. These 

 two lines may therefore be regarded as continuations of one and the same line. 



When I thus speak of the unity and continuity of the line between Crowborough 

 and Balcombe, and to the west of the latter place, I am tacitly referring the forma- 

 tion of the Ashdown and St. Leonards ridge to the existence of a single antichnal 

 line, or (speaking with reference to my theoretical views) of a single longitudinal 

 fissure. It is very possible however that this characteristic ridge may be due to 

 the original and simultaneous formation of several longitudinal fissures, so near to 

 each other, that we are unable to distinguish their separate effects by the outward 

 structure of the elevation. Still such a system of hnes, occupying but a small 

 transversal space (as in the present instance), may in descriptive language be spoken 

 of as a single line, and we may still assert the probable identity of this system and 

 the Wadhurst line as in the preceding paragraph. 



On the south of Balcombe and between that place and Cuckfield is an east and 

 west valley which forms a distinct feature in that neighbourhood, and of which the 

 length and direction are marked on the Ordnance Map by the course of a small 

 stream, one of those which, by their confluence, ultimately form the river Ouse. 

 In descending into this valley on the northern side, by Slaugham Park, the beds are 

 observed to dip southward with the hill, which shows that the Crowborough line must 

 pass to the north of the Park, agreeing with the direction previously assigned 

 to it. This direction, continued westward, would pass very near Horsham, but 

 that neighbourhood presents no external indications of disturbance, the strata being 

 very nearly horizontal. I examined the quarries near Warnham, at Theall near 

 Slinfold, three miles west of Horsham, at Stammerham, two miles south-west of it, 

 and at Tower Hill near Horsham. In all these places there was scarcely a sensible 

 deviation from perfect horizontality*. There was no evidence of the continuation 

 of any distinct anticlinal line west of St. Leonards Forest. 



Cuckfield Line. — On the south of the valley just mentioned as passing between 

 Balcombe and Cuckfield is a small elevated range, sufficiently determinate to give 

 to the valley which it bounds a perfectly distinct character. It is a subordinate 



* Dr. Mantell has remarked, that " the dip of the strata around Horsham and Tilgate Forest is ex- 

 ceedingly variable ; the general inclination is towards the S.E." He also states that the beds in the 

 Forest are nearly horizontal. The fact is, that all around Horsham the beds are so nearly horizontal, that 

 I think it impossible to assign to them any prevailing dip. In such a case the slightest local cause might 

 determine the existing small dip in each locality. 



