So MIDDLE ALBIAN STRATIGRAPHY 



These borings in the area of the Kent Coalfield show that the sequence in the Lower 

 Gault expands considerably eastwards from the outcrop between Folkestone and 

 Maidstone. In this trough area the eodentatus and lyelli Subzones are well developed. 

 The whole sequence thins towards the coastal margin of Kent from the Isle of Thanet 

 to St. Margaret's Bay northeast of Dover. 



F. Selection of sections in France 



It is not possible here to describe the Middle Albian stratigraphy of northern and 

 central France in the same detail as the English sections. The French sections 

 require just as long and careful study, and must include temporary sections seldom 

 available on a chance visit and which are thus the prerogative of our colleagues in 

 France. The purpose of this portion of the work is to make a comparison of the 

 English sequence with a representative selection of sections of four regions ; (i) the 

 Boulonnais ; (ii) the outcrop extending from the River Ornain (Meuse) to the River 

 Armance (Yonne) which includes also parts of the Departements of Meuse, Marne, 

 Haute-Marne, Aube and Yonne ; (iii) the Pays de Bray ; and (iv) the Pays de Caux 

 (text-fig. 33). 



(i) COMPARISON BETWEEN WISSANT & FOLKESTONE 



The Albian deposits of the Boulonnais describe a narrow outcrop at the foot of the 

 Chalk escarpment extending from the coast at Petit Blanc Ne'z south-eastwards to 

 Lottinghen and then roughly westwards towards the coast to disappear beneath the 

 dunes at Hardelot Plage. The deposits rest upon Aptian sediments at Wissant, but 

 inland they may rest directly upon Aptian, ' Wealden ', Jurassic, and, near Caffiers, 

 on Palaeozoic rocks. The exposures in the shore and in the cliffs between Wissant 

 and Petit Blanc Nez are indicated in text-fig. 34. 



The Gault of the Wissant area was briefly described by Barrois (1873, 1875, 1878, 

 but particularly 1879 ; 27-28), Price (1879, I 88o ; 34 etc.) and Jukes-Browne (1900 ; 

 378-381), but it was not until 1938 (a 98-121) that a good detailed description was 

 given by J. -P. & P. Destombes. Barrois had considered that the sequences at 

 Folkestone and Wissant were not comparable in detail, a conclusion with which the 

 present writer agrees. Destombes & Destombes, however, followed Price in consider- 

 ing that the Wissant succession is comparable to that of Folkestone, although reduced 

 in thickness ; a view accepted by Spath (1943 ; 721). 



P. & P. -J. Destombes have written an emended account of the Wissant sequence 

 (1965 ; 257-260), the lithological accuracy of which can be confirmed by the writer's 

 own examination of the section. However, their subzonal classification of 1938 and 

 the implied classification of 1965 requires some revision at certain levels as also does 

 the account by Marie (1965 ; 280-284, table 1). In April 1967 the writer observed 

 good clean sections in the Lower Gault both in the cliffs and in the foreshore, and 

 from the study of these the graphical section (text-fig. 35) has been drawn. The 

 primary bed numbers employed are those used by Destombes & Destombes (1965 ; 

 258), and the correlation with Folkestone is shown in text-fig. 36. 



