330 REPORT— 1888. 



consisting of clialk, which is overlain by about 35 feet of Grlacial beds ; 

 bat, when we go a few yards to the southward, the chalk is seen to end 

 abruptly in a cliff that is quite vertical, and in some places overhanging ; 

 and beyond this point no solid chalk is seen in the section. On the sur- 

 face this bold feature is so well masked by the thickening of the drifts 

 that its presence would not be suspected. There is, indeed, an obscure 

 line to be traced for a short distance across the fields, where the ground 

 sinks for a few feet, but this is quite uncertain, and is probably nothing 

 more than a bank of the uppermost gravel, such as is common in the 

 neighbourhood. 



When this cliff formed part of the ancient shore-line, though the sea 

 stood at somewhere about its present level, the physical geography of the 

 country must have been quite different. 



The headland must then have been a far more prominent feature than 

 it is to-day, that rubble heap of drift which we call Holderness having 

 then no existence, except as a shallow sea-bottom, across which through- 

 out Yorkshire, and probably throughout Lincolnshire also, the waves 

 washed till they reached the eastern foot of the Wolds. There is evidence, 

 moreover, that the sea has reached into the hollow ground on the northern 

 side of the headland, now occupied by the drift, since at Speeton an 

 estuarine shell-bed is found below the Glacial series, resting on the 

 Speeton Clay, at a short distance from the edge of the chalk escarpment. 

 This bed, however, is at least 85 feet above high-water mark, and is, there- 

 fore, probably not exactly contemporaneous with the Sewerby Cliff-beds. 



It is where the present shore-line intersects this ancient shore-line 

 at Sewerby that our excavation has been carried out, and as the lines 

 cross each other at a low angle — the recent beach striking N.E. and S.W. 

 nearly, while the old cliff strikes about E.N.E. and W.S.W. — we have been 

 able to work for some distance along the denudation-slope of the recent 

 cliff, where the ancient beach deposits are stripped of their covering of 

 boulder clay; but the gradual recession of the old cliff inland has brought 

 us so far into the slope that this mode of working can no longer be 

 carried on. 



The face of chalk in the old cliff above the old tide-level is every- 

 where smoothed and rounded in a manner strikingly different from the 

 angular mode of weathering of the recent cliff adjoining. 



Against it are banked the deposits we have excavated, in the order 

 now to be described. 



The Old Sea-beach. — At the bottom, resting on the terraced ' scaur' of 

 the chalk, is a sea-beach composed of water-worn chalk pebbles of all 

 sizes, from fine gravel to large stones over a foot in diameter. These 

 are nearly always of the flat oval form that characterises this chalk as a 

 beach material. Many are perforated by the borings of Pholas, Saxicava 

 and Cliona, which shows that an uncovered scaur of chalk has ex- 

 tended at least to near low-water mark. Besides chalk there are also 

 pebbles of grey flint, some rather large in size, of the kind found in the 

 Middle Chalk on the north side of the headland. The chalk in the imme- 

 diate neighbourhood has no flint, and these pebbles must have drifted 

 not less than four or five miles. They are more plentiful than in the 

 recent beach at this place. 



The old beach also contains a few pebbles that are not of local origin. 

 These are comparatively very rare, but we have this year found more of 

 Buch stones, and some of larger size, than in our last year's excavation, the 



