302 



H. A. Baker — The Pre-Thanetian Erosion 



Future quarrying operations in the neighbourLood sliould prove 

 interesting. 



To the writer the point of greatest interest was the discovery that, 

 as the concealed zonal outcrops approach within the sphere of 

 influence of the ancient Charnian ridge, they suffer an abrupt change 

 of strike and take on a northerly as well as a westerly trend. The 

 evidence seems convincing that in this area the belt of maximum 

 denudation of the Chalk in pre-Thanetian times possessed a 

 N.W.-S.E. alignment, and this fact must be ascribed either to 



Miles. 

 5 lO 



20 



/ 



/" 



Map shovitng coatbiirs ui ' 



the SuT^-Eoccne and Sub-^'^A^orwlck 



Pliocene ChaiK surface \\^l}en f^^Y'''^ [ 



Lhekisecf fe chaiK is cor- ^-*-~i\\ \\ \ 



recced fo 'hcfiTfntaii^ at „^ \ \ \ \ \ 



sea-le\)e[ \( \ \ \^ 



The line^ also seroe as the. +\ 1 \\ v \ NfajLi \ A' 



isopachyks of IheChalk \ \\ v ^ | \ \ \ ^f^'^''^ \ 



QicdK. Siirfo.C£ConIairsx. _ ^ p \ \ \\y ' j ' 



-o — o-3ound<3ri'eicf 7€rfori<25'.)^_ ^/ ) 1 \V ..q/ i \ 

 — + — +3our(C[ary of Cra<3. +«,yv / \ , / ^^' ' ' 



ji^ 



\ II055' I 



ryoTLraa- + ^,y7 / \ \ / ^X" // / 

 b-oundancs. /^'Ve** V , \ \ / ^'^^ 



Coran<}i/in(/in 



'A^i 



.Cu!fcrc( M \ )^ 



\o^Sr] 



I OOO 



/ 



Marsvbih 



&l'ul'^o^-^, > 



!//es 



quadratvd 



r,g2. 



surroLK 



ARE.A 



the influence exerted by the form of the Palaeozoic floor at that time 

 or else to the operation of Cliarnian posthumous movement during 

 the erosion of the Chalk. The area furnishing this evidence of 

 a tendency on the part of the Chalk zonal outcrops to assume a 

 N.W.-S.E. alignment is very small, but considering the great extent 

 to which the erosion of the Chalk has been carried during later 

 times, the fact that even some evidence of this tendency has been 

 preserved to us can only be regarded as a fortunate accident. 



We are, perhaps, hardly in a position to consider the question of 



