366 



R. M. Brydone — Zone of faster pilula 



Tertiaries is just about 55 feet, as at Burrow Head, so that there are 

 at least 35 feet of chalk at Telscombe and some 15 feet in the centre 

 of the Castle Hill syncline higher than anything at Seaford. 



The following general section will apply to all the chalk of this 



Zone of A. quadratus in the Sussex Cliffs. 



Chalk inaccessible at Telscombe, estimated at 

 Chalk measm-ed at Telscombe, inaccessible at New- 

 haven and only partly preserved at Seaford 



ft. 

 30 



19 



ft. in. 

 49 



ft. in. 

 49 



Strong flint seam. 



Chalk 5 6 to 7 



Strong flint seam. 



Chalk 60 66 



Strong flint seam. 



Chalk 11 13 



(In the upper part of this bed there may be a thin 

 seam of O. pilula at Newhaven, of which there is 

 no trace at Seaford. The Telscombe section 

 affords no test.) 



Strong flint seam. 



Chalk 9 10 3 



(There are two marl seams in this bed at Tels- 

 combe and traces of marl seams at Newhaven, 

 but none at Seaford.) 



Strong flint seam. 



Chalk 60 60 



(There is a thin marl seam just above the base of 

 this bed at Newhaven.) 



Broad seam of loosely set flints. 



Chalk 36 56 



Weak marl seam. 



Chalk 16 26 



Flint seam. 

 Chalk ^ . . .10 16 



92 6 to 101 3 



Marl seam marking top of zone of 0. pilula. 



Attention is called to the fact that the lowest 3 to 4 feet are 

 marked off by a mai'l seam and embrace a flint seam. This will be 

 found to be repeated in the Isle of "Wight, and it is also the case at 

 Hursley, Compton, and WestMeon in Hants, where the bounding marl 

 seam is very faintly marly and little more than a parting. It forms 

 a striking combination with the even more widely constant bed at 

 the top of the zone of 0. pilula and immediately preceding it. 



There is little to be said about the general fauna of the zone, only 

 the lowest beds being in practice accessible for any distance, and these, 

 as I have previously pointed out,' being characterized chiefly by the 

 gradual dying out of such of the leading fossils of the subzone of 

 abundant 0. pilula as succeeded in outliving it. Thus, while 



^ ' ' The proposed recognition of two stages in the Upper Chalk ' ' 

 Mag., February, 1913, p. 61. 



Geol. 



