IN THE ANGLO-PARIS BASIN 145 



has exactly the same degree of representation as at Sandling. There is strong 

 evidence to indicate that in lithological sequence and Subzonal representation the 

 remainder of the Gault sequence is uniform between Brabourne and the A 249 Clover 

 Leaf on the Maidstone By-Pass, and they are certainly identical from Hollingbourne 

 to the A 249. 



In the area of the Kent Coalfield to the east, the pattern is not so clear but the 

 eodentatus and lyelli Subzones sediments are well developed to the N. and NW. of 

 Dover in the Guilford, Tilmanstone, and Chislet collieries. The Lower Gault as a 

 whole is much thicker here than at the outcrop, but further east, on the Thanet and 

 E. Kent coast, the Gault in its entirety thins rapidly. 



At the valley of the Medway north of Maidstone, the outcrop swings westwards 

 through an arc of about 12 °. The change in the lithological sequence is striking 

 (text-fig. 3, p. 14) as the outcrop turns away from the line parallel to an axes to one 

 that cuts across the structural trend. From the four-division sequence in the Maid- 

 stone By-Pass, the Lower Gault expands into the six-division sequence recognisable 

 from Paddleworth near Snodland westwards at least as far as Dunton Green. The 

 central area of this Middle Albian trough seen in section at the outcrop occurs 

 roughly in the position of the Sevenoaks Brick Works but it migrated slightly NE. 

 during Middle Albian times. At Sevenoaks, the top of the Folkestone Beds contain 

 developments of soft sandstone in regular beds. This is overlain by a comparatively 

 thick development of the mammillatum Zone sediments. The top of lyelli Subzone 

 and the lower part of the spathi Subzone are represented by fine clays in contrast to 

 glauconitic clays or loam at Ford Place on the one side and at Dunton Green on the 

 other. The overlying ' upper dentatus-spathi nodule bed ' contains an ammonite 

 assemblage identical to that seen in all sections from Parsons Corner, Snodland, 

 to the Shere By-Pass. The remainder of the Lower Gault Divisions at Seven- 

 oaks when compared with Ford Place show the offset of the trough axes towards 

 the NE. 



The whole Middle Albian sequence thins from the Sevenoaks Brick Works towards 

 Dunton Green. Further west, the eodentatus, lyelli, and spathi Subzones at least, 

 expand and are well developed in the area between Brasted and Covers Farm west 

 of Westerham. Unfortunately the rest of the Lower Gault is not exposed although 

 from the Brasted well it also is expanding west of Dunton Green. This boring also 

 demonstrates that the mammillatum Zone troughs do not always correspond to those 

 of the Middle Albian sediments, for here the mammillatum Zone sediments are much 

 thicker than those to the east and west and are little condensed. In the Addington 

 Pumping Station situated 9! miles WNW. of Dunton Green the Lower Gault is of 

 much the same thickness and probably lies near a common ridge axis, running NW. 

 from Dunton Green. 



At the Buckland Sand & Silica Co's pit together with Wray Common, at Reigate, 

 the sequence although in general thicker and the sediments coarser, shows a similar 

 succession to that seen at Ford Place. At Shere, however, the eodentatus, lyelli and 

 basal spathi Subzones are again relatively well developed, but from here westwards 

 to Farnham the information is either poor or of uncertain value. Moreover, the 

 outcrop is faulted over much of this stretch of country. 



K 



