Wealden District and the Bas Boulonnais. 51 



Description of the Map. 

 Plate I. 



The map contains the Bas Boulonnais on the east, and the disturbed district, 

 mentioned in the memoir, as far west as Southampton. The greater part of the 

 great Wiltshire plateau of chalk lies still further to the west, and is too extensive 

 to be included. 



The boundary of the disturbed district, denoted by a black dotted line, com- 

 prises that extent of country (as far as the map extends) which I conceive to have 

 been simultaneously disturbed. The interior dotted black line indicates that part of 

 the district in which the elevatory force is conceived to have acted generally with 

 greater intensity than in the remaining portion. It comprises the whole district 

 of the Weald (as defined by the great Wealden denudation) and that of the Bas 

 Boulonnais. These boundaries are, of course, to be considered as only approximate, 

 and independent of local irregularities. 



The red lines are lines of elevation, whether they be faults, anticlinal lines, or 

 lines of curvature. The continuous red lines denote lines of elevation clearly 

 established by observation ; the dotted lines denote those the existence of which 

 rests on less positive evidence. Synclinal lines are not marked. 



The map has been engraved on a reduced scale from that of the Ordnance 

 Survev. 



