in the South English Chalk. 365 



The subzone in Sussex corresponds palseontologically in the closest 

 way with the same subzone in Hants. The only guide fossil for 

 Hants which may be rare in Sussex is Terehratulma Rowei; but 

 several specimens have been found, and their relative scarcity is 

 probably due to the absence of clean unbattered surfaces, which alone 

 are favourable for finding so small a fossil. 



In the matter of lithological details the upper belt of O.pilula offers 

 some strikingly minute correspondences. It is invariably the rule 

 in Hants as it is in Sussex that the lowest 12 to 18 inches are marked 

 off by marl seams, and that the highest 3 feet or so, characterized by 

 0. pilula of exceptional size and shape, are marked off by marl seams 

 (with a flint seam almost always about midway). 



C. Zone of A. quadratiis. 



All the synclines which have been defined contain as their highest 

 element outliers at least of this zone. In the relatively shallow 

 Rottingdean syncline the outlier is split by Rottingdean Gap into two 

 parts, which occupy the summits of the hills east and west of 

 Rottingdean and are quite inaccessible from the shore; but a fair 

 though scanty section through some of the lower beds is afforded by 

 the road cutting down the east side of East Hill. 



At the west edge of the Telscombe syncline there is probably an 

 outlier of this zone on the east slope of Portobello Hill. In the 

 centre of the Telscombe syncline we get the base of the zone 

 descending to some 8 feet below high-tide level, but unfortunately 

 there is no beach here, and so only a small thickness of wave-washed 

 chalk becomes accessible. (It is, however, interesting to note that the 

 12feet or so which is accessible agrees most closely in lithological details 

 with the JS^ewhaven and Seaford Head sections.) The deepest part 

 of the syncline is about a quarter of a mile west of Telscombe Stairs. 

 Here the cliff, which is practically solid chalk, just exceeds the 

 100 feet contour and the top of tlie zone of O.pilula is about 7 feet 

 above low-water mark, so that there must be over 90 feet of the 

 zone of A. quadratus preserved. The bed-to-bed thickness of the 

 greater part can only be estimated here but the lower 70 feet can be 

 measured at Telscombe Stairs. 



From Telscombe to Newhaven Harbour this zone never ceases to 

 occupy the top of the cliff. In the Castle Hill syncline it comes 

 down almost to beach level (here a few feet above high-water mark). 

 The lower beds are easily accessible (though very dirty) over a long 

 distance, and a considerable thickness, amounting to about 55 feet, is 

 measurable at Burrow Head, while a further 15 feet (about) appears 

 to be preserved at the top of the cliff in the centre of the syncline. 



When chalk reappears on the east side of the Ouse Valley at the 

 Buckle Inn it is chalk of this zone which is at the surface and 

 composes the low cliffs immediately round the Buckle Inn. A fair 

 section of probably rather higher beds used to be furnished by a low 

 cliff between here and Seaford, which is now sloped, and liidden in 

 the lower part by a sea-wall. 



Finally we come to the Seaford Head section, easily measurable 

 owing to the dip. The full thickness preserved here beneath the 



