of the London and Hampshire Basins, Sfc. 113 



everywhere the same geological features, except where it is 

 broke in upon by the sea ; and those features, as far as regards 

 the Weald Valley, have long been considered as dependent 

 upon denudation. 



It might be supposed that this anticlinal ridge was the ori- 

 ginal form of the strata which compose it, and was one of 

 those undulations which are supposed to take their rise at the 

 period of deposit, — were it not for the appearance of a system 

 of transverse valleys, corresponding with, and produced by 

 cracks and fissures in the basset edges of its strata; with such 

 divergences and ramifications of those fissures, and other 

 signs of fracture, as might be expected to be produced in 

 the stretching and bursting up of ponderous and frangible 

 bodies. 



But it will be said, that although the elevation of an anti- 

 clinal line explains the longitudinal fracture of the incumbent 

 strata, it does not satisfactorily account for the transverse fis- 

 sures ; and we are naturally led to look for evidence of some 

 obliquity in the long diameter of the ridge correspondent 

 with them, and with a force acting transversely to it, — and 

 we shall not be disappointed. The order of succession in the 

 emergence of the inferior strata, and the manner in which 

 they attain a geographical pre-eminence over the superior 

 ones, in the direction of the short axis of the ridge, or north 

 and south, are sufficiently obvious, and are familiarly known 

 by the sections of Smith, Conybeare, &c. But the same 

 order, in a direction east and west, or of the long diameter of 

 the ridge, is not so apparent ; but a gentler inclination in that 

 direction is easily demonstrated. The lowest bed, brought 

 up by the act of denudation on the English side of the Chan- 

 nel, belongs to the lower part of the Wealden ; and it rises 

 at Crowboro' Hill, about the middle, and in the widest part, 

 of the Weald, to the height of 800 feet above the level of 

 the sea ; whilst, in the western part of the ridge, the same 

 stratum may be computed to have sunk 900 feet* below 

 it. This is proved by subtracting the thickness of the 

 overlying strata at Inkpen Beacon, or the highest elevations 

 of the chalk platform in Hampshire and Wilts. This mode- 

 rate obliquity, a rise of 1700 feet in 80 or 100 miles, cor- 

 responds with the order of denudation f, and also explains 



* It is not to be supposed that this is any thing more thon an approxi- 

 mation to the true adnieasurenicnt. 



t Mr. Murchison has ol)Scrved the inclination of the lower beds towards 

 the chalk of the Alton-Hills (Geol. Trans, vol. ii. New Series, p. 101). 

 that is, westward, or in the direction of the long nxis of the ridij;e; and 

 this inclination or lateral bearing is to be observed in every considerable 

 advance of the upper strata, toward the centre of the Valley of the Weald. 

 New Series. Vol.5. No. 26. Feb. 1829. Q why 



