604 SCIENCE PROGRESS 



to the north and the south " (the italics are mine). In other 

 words, we should have to all intents and purposes a ridge of 

 wealden beds above the chalk, with which I agree. 



Breaks in the continuity of any deposit must constantly 

 occur ; and, if in order to account for the present non-exis- 

 tence of the chalk in the central Weald it is assumed that it 

 never was there, one is on safer ground than in assuming a 

 method of plain production by the sea, which is not even a 

 plane surface ; nor, as far as experience goes, the ordinary 

 result of sea action, which tends to forming concave surfaces 

 rather than convex. 



One has only to postulate instead of a " comparatively 

 plane surface sloping north and south from a central line" a 

 ridge of wealden beds thrust up higher than their adjacent 

 chalk to explain all the present phenomena, ab initio, without 

 the intervention of the sea at all. 



Mr. Topley very justly disposes of the probability of sea 

 or ice-action having moulded the Weald features, from the 

 absence of any of the indications usually left by ice-sheets or 

 glaciers ; and shows also how all the gravels of the Weald are 

 such as would be furnished by the wealden strata themselves 

 and by the relics of the worn-back escarpments of the chalk. 



Though it is certain that during this long geological period, 

 perhaps reaching back to the " London Clay," changes of 

 elevation have taken place in the body of the chalk, there is 

 no evidence of any great relative change in its several por- 

 tions. Various problems still remain for investigation ; viz. 

 that of the Clay with flints, the Lenham Beds, 1 the Coomb 

 Rock, etc. ; but the new interpretation of the glacial periods, 

 which I have given elsewhere, 2 together with a juster view of 

 the processes that have been at work within the Weald, serves 

 to explain this Rock, and incidentally to punctuate the 

 immense antiquity of man, who has inhabited this area 

 during a succession of climates each with its special fauna, 

 and has outlived the span of existence allotted to successive 

 species of elephant, with perhaps only one break in continuity 



1 These beds, which are found at different elevations on the Downs, have 

 lately, from their fossil contents, been assigned to the Miocene period by Mr. 

 Bullen Newton. 



8 Changes in Climate (The Glacial Epoch explained). Price I s. id. (W.Baxter, 

 Printers, Lewes.) 



