44> Mr. P. J. Martin on the Anticlinal Line of 



them to you to be published, if you please, iii your Magazine. 

 And, with only two corrections, which I had })roposed to make 

 before their appearance in the Society's publications, I pledge 

 myself to the general fidelity of the details both of fact and theo- 

 retical inference. In the last paragraph of my unfortunate paj)er, 

 you will observe that I propose to myself and to the Geological 

 Society a continuance of the investigation into other parts of the 

 great anticlinal line. This I shall now do with your permission ; 

 and I shall unreservedly and without hesitation finally reproduce 

 my original proposition of the contemporaneity of upburst and 

 denuding Hood over an area of at least four degrees of longitude, 

 from the chalk of the Pas de Calais to where the line of eleva- 

 tion at Devizes is met by that of the general line extending from 

 S.W. to N.E. from the Dorsetshire to the Yorkshire coasts. I 

 should also say, of as many degrees of latitude, but, except as a 

 speculation of the highest order of probability, I am not prepared 

 to include the parallel lines of elevation of the Isle of Wight in 

 this disquisition ; and it would be an area inconveniently large 

 for the discussion of matters of a practical natm'c. 

 I am, dear Sir, 



Yours very truly, 



P. J. Martin. 



[Read before the Geological Society, December 16, 1840.] 



A paper was read before the Geological Society in 1827, 

 afterwai-ds enlarged into a small quarto volume, published the 

 following year, under the title of a '^ Memoir on a part of West- 

 em Sussex, with some observations on the Weald Denudation,'^ 

 &c. In this paper some new facts and some speculations were 

 advanced on the construction of the Weald, — its cross fractures, 

 drainage and other phsenomena, illustrative of the simultaneous 

 operations of upheaving force, and violent aqueous abrasion. 



In pursuance of the subject, some additional remarks were 

 offered to the public in the Philosophical Magazine for February 

 1829, on the extent and magnitude of the abraded materials; 

 and to show also, that although the word " denudation " was 

 usually restricted to the Weald valley, the chalk country, espe- 

 cially that of Hampshire and Wiltshire, ought to be included in 

 the same category ; and, in fine, that the upburst of the Wealden, 

 and the area comprised in the chalk-boundaries of what was 

 called '* the great denudation of the Weald,'' did not present any 

 features attributable to disturbing forces, distinct and separable 

 from those of the surrounding districts. 



The object of the present inquiry is to trace the lines of dis- 

 turbance from and into the Weald, through the great expanse of 

 chalk which separates the western parts of the basins of London 



