CHAPTER XXII. 
Denudation of the Valley of the Weald, continued — The alternative of the pro- 
position that the chalk of the North and • South Downs were once continuous, 
considered — Dr. BueMand on the Valley of Kingsclere — Rise and denudation 
of secondary rocks gradual — Concomitant deposition of tertiary strata gradual 
— Composition of the latter such as would result from the wreck of the secon- 
dary rocks — Valleys and furrows on the chalk how caused — Auvergne, the 
Paris basin, and south-east of England one region of earthquakes during the 
Eocene period — Why the central parts of the Loudon and Hampshire basins 
rise nearly as high as the denudation of the Weald — Effects of protruding 
force counteracted by the levelling operations of water — Thickness of masses 
removed from the central ridge of the Weald — Great escarpment of the chalk 
having a direction north-east and south-west — Curved and vertical strata in the 
Isle of Wight — These were convulsed after the deposition of the fresh-water 
beds of Headen Hill— Elevations of land posterior to the crag — Why no Eocene 
alluviums recognizable— Concluding remarks on the intermittent operations of 
earthquakes in the south-east of England, and the gradual formation of valleys 
— Recapitulation. 
Extent of denudation in the Valley of the Weald. — ' It would 
be highly rash,' observes Mr. Conybeare, speaking of the denu- 
dation of the Weald, c to assume that the chalk at any period 
actually covered the whole space in which the inferior strata 
are now exposed, although the truncated form of its escarpment 
evidently shows it to have once extended much farther than at 
present 
We believe that few geologists who have considered the 
extent of country supposed to have been denuded, and who 
have explored the hills and valleys of the central, or Forest 
ridge, without being able to discover the slightest vestige of chalk 
in the alluvium % will fail to participate, at first, in the doubts 
here expressed as to the original continuity of the upper secon- 
dary formations over the anticlinal axis of the Weald. For our 
own part, we never traversed the wide space which separates the 
North and South Downs, without desiring to escape from the 
conclusions advocated in the last chapter ; and yet we have 
* Outlines, p. 144. f See above, p. 29.5, 
