and other Valleys of the East of England. 189 



sions, pretty nearly in the condition that their respective seas 

 had left them, — the only exception, and that of a very moderate 

 nature, consisting of the early tumefaction that began over the 

 Wealden area prior to the deposit of the older tertiaries, as shown 

 by Mr. Prestwich. 



In concluding, I wish to withdraw an opinion expressed by 

 me in a paper published in the Philosophical Magazine for 

 April 1863, that the departure of the Wealden Valley between 

 Maidstone and Dover from the linear east and west direction was 

 due to the influence of a production of the palaeozoic barrier of 

 the Pas de Calais beneath that part of Kent. It is evident, 

 from the views put forward in this paper, that such an opinion 

 is no longer tenable by me. At the same time that I adhere 

 fully to the other views there expressed as to the direction of the 

 extension of that barrier, I can no longer attribute that depar- 

 ture to any other than the causes shown in the Map, — that is to 

 say, to the rectilinear upheavals of the South of England having 

 never reached in Kent further east than the verge of the innermost 

 Kentish circle — a part of whose periphery forms the Dover extre- 

 mity of the Downs between that place and Maidstone, while 

 the other, or Maidstone extremity, is formed of a powerful 

 example of the series of inequalities of the third group, caused 

 by the invasion of the Isle of Wight circles into those of 

 Kent. 



I have little doubt, from the investigation that I have already 

 been able to give to the subject, that the river- and other val- 

 leys of the secondary and tertiary basins of Northern France 

 and of Belgium have been formed by the action of that portion 

 of the arcs of the two series of circles which are (after allowing 

 for the hiatus of the British Channel) complementary to those 

 delineated in the coloured Map. I have not, however, yet had 

 the time to perfect my evidence sufficiently to embody it in a 

 satisfactory form. 



P.S. Since the above went to press, the Map of the Geological 

 Survey for the north-west side of the Weald has appeared. It 

 shows the Isle of Wight arc made by Chobham ridges distinctly 

 formed by the upper Bagshot brought out by denudation, pre- 

 cisely as I have by survey myself ascertained to be the case in 

 the Kentish arcs in Eastern Essex, where the lower Bagshot is 

 brought out over the London Clay by denudation. The Kentish 

 arc running through Leith Hill and directly opposing Chobham 

 ridge, is also brought out by the lower tertiary outliers upon the 

 chalk that follow the curve. The continuation of the Kentish 

 arc across the Weald is also to be followed by a ridge of Paludina 

 limestone in the Weald clay. I look with interest to the future 



