Rev. Dr. Irving — Elevation of the Weald. 405 



simultaneously commensurate throughout the whole distance from 

 east to west; but I think it can be shown that there are fairly 

 strong grounds for doubting this. 



1. We have the record of at least two important lines of move- 

 ment : (a) the Isle of Wight and Purbeck anticlinal ; (b) the 

 anticlinal axis of Kingsclere and Inkpen — the latter probably 

 initiated at the age of the Upper Chalk as worked out by Dr. 

 Barrois. 1 The former of these must have been initiated at about 

 the beginning of the Oligocene period, in order to account for the 

 relative lie and position of the Eocene and Oligocene strata of the 

 island : 2 the latter (as I have previously pointed out elsewhere 3 ) 

 was, in all probability, somewhat advanced in later Eocene time. 



Along each of the lines of movement the strata have been 

 thrown into a position of much greater inclination on the north 

 than on the south side. This seems to follow as a simple mechanical 

 result of the resistance offered by the greater proximity of the great 

 Mesozoic area (and perhaps the underground conformation of the 

 Palaeozoic rocks) of central Mercian England. Such movements 

 could scarcely leave the western end of the Weald unaffected. These 

 conditions fail when we attempt to apply them to the eastern part 

 of the Weald. There are also such minor axes of elevation as those 

 of Winchester and Portsdown, probably later Eocene. 4 



2. An examination of the stratigraphical structure of the Weald 

 shows that the resultant displacement of the strata in the western 

 part of the Weald is greater than that of the eastern part. This is 

 well seen in the high angle of inclination of the chalk of the Hog's 

 Back, and of the Neocomian strata of the Hindhead anticlinal. 3 It 

 is reasonable to suppose that these recorded movements were initiated 

 much earlier than those which have brought up the strata of the 

 eastern part of the Weald to their present position ; and this sup- 

 position is supported by the fact that the general axis of elevation 

 of the Weald, which can be traced from its exposure in the cliffs 

 east of Hastings, through Crowborough Beacon (the highest point 

 in the Hastings Sands), Horsham, and Petersfield, 6 seems to be 

 independent of, and posterior to, certain earlier movements which 

 determined the initiatory stages of elevation of Hog's Back and 

 Hindhead. 



8. Mr. Topley, 7 has given us a table of culminating points of the 

 chief formations of the Weald, showing, for each of the formations, 

 the Chalk (both north and south), the Lower Greensand, and the 

 Hastings Beds — "a general fall of the summits" from west to east; 

 a result scarcely to be accounted for by greater denudation towards 

 the east, but probably connected with the greater disturbance to 

 which the western part of the Weald has been subjected. It is in 



1 See " Recherches sur le Terrain Cretace superieur," figures 4 and 8 on the plate 

 at the end; also p. 113. 



2 See [e.g.) the section (No. 3) of Ramsay's Geological Map of England and 

 Wales. 3 Q.J.G.S. vol. xliv. p. 181. 



4 Barrois, op. cit. p. 115. 



5 See Topley, "Geology of the Weald," p. 232. 



6 Topley, ibid. 7 Ibid, pp. 240, 241. 



