Wealden District and the Bas Boulonnais. 



49 



SECTIONS OF THE BAS BOULONNAIS. 



26. 



W.N.W. 



Maninghen. Hesdres. 



Houillefort. 



E.S.E. 

 8 



^ 7 



27. 



Oxford Clay. f3.) 



Coast Section. 



La CrSche. 



29. 



Boulogne. 



Kimmeridge Clay. 



References. 

 8. Chalk, Upper Greensand and Gault. 

 7. Beds between the Gault and Kimmeridge Clay. 

 6. Kimmeridge Clay. 

 5. Sand beds in the Kimmeridge Clay. 



4. Coral Rag. 



3. Oxford Clay. 



2. Oolite. 



1. Mountain Limestone. 



Description of the Sections of the Bas Boulonnais. 



The preceding group represent sections of the Bas Boulonnais. The first three 

 (26), (27), (28), are nearly parallel to each other, and nearly perpendicular to the 

 direction of the coast north and south of Boulogne. The first shows the unconform- 

 able position of the lower oolite on the mountain limestone about Marquise and 

 Leulinghen, and of the cretaceous system in the north-eastern corner of the district. 

 The second section shows the superposition of that system on the Oxford clay. 

 The third (28) exhibits the structure of Montlambert, the highest hill within the 

 chalk boundary. The rapid rise of the beds on its east side brings up the Oxford 



VOL. VII. SECOND SERIES. H 



