400 MK. G. W. LAMPLUGH ON THE 



The slielly sand occurs as a twisted seam, about 24 feet long, 

 but never exceeding four inches in thickness, iu a thin band of 

 Boulder-clay which dies out rapidly between stratified beds. It 

 has yielded about 20 species of moUusca ; while in the stratified 

 beds above and below the strip of Eoulder-clay there is no con- 

 temporaneous fauna. Its position is about 60 feet above sea-level, 

 this being the only instance in which a fossiliferous patch has been 

 found more than two or three feet above high-water mark, or in 

 which it has been possible to examine the underlying section. It 

 fully confirms my previously expressed views as to the transported 

 character of the shell-bearing patches, and also satisfactorily 

 completes the identification of the lower Boulder-clay of Plam- 

 borough Head with the Basement Clay of Holderness. 



(k) SoutJi Sea Landinc/ to High JStacJcs. — Beyond the last-men- 

 tioned section for upwards of a mile there is nothing to call for special 

 comment. The cliff, generally about 125 feet in height, is capped 

 with 30 to 60 feet of drift, which is usually separable into two 

 Boulder-clays about equal in thickness ; but in a few places the lower 

 division disappears into stratified beds,- and only the Upper Clay 

 persists, over sands or chalkj^ gravels. In the neighbourhood of Old 

 Falls (where a very precipitous path leads to the beach) the clif?- 

 line intersects two or three small but sharply-defined mounds, and 

 in each case, as in Beacon Hill, it is to a rapid thickening of the 

 intermediate gravels under the Upper Clay that the surface-feature 

 is due. In one of these instances this clay distinctly passes into rough 

 morainic drift-gravel. 



Beyond Old Ealls the Chalk surface rises gradually, till there is 

 in one place oulj'^ about 12 feet of drift above it, consisting chiefly 

 of gravelly red Boulder-clay ; but whether this clay re2)resents the 

 upper or lower division, or both, it has not been found possible to 

 decide, though the evidence favours the first-mentioned supposition. 



In the neighbourhood of Cattlemcre Hole, within half a mile of the 

 extremity of the headland, the solid rock sinks rapidly again, and the 

 drifts proportion atel}'' thicken till they once more attain a depth of 40 

 or 50 feet. Here the section shows many points of resemblance to that 

 west of Danes' Dyke, chalky gravels, with sand and laminated silt, 

 being developed at the expense of the Boulder-clays, till they 

 monopolize for a short space the whole section, save that a thin 

 band of Basement Clay, so chalky as to be scarcely distinguishable 

 from the underlving chalk-rubble, persists at the base. 



(1) HigJi Stack (PI. XIII. fig. 8).— At High Stacks the easternmost 

 point of the headland is reached, and the cliff'-line swings round to the 

 northward. Here the section intersects another hidden valley in the 

 Chalk, a broad, shallow hollow, with a steep but narrow ravine in the 

 centre. This seems to be the prolongation of the Bempton valley, and 

 is evidently the result of stream erosion. The approach of the little 

 ravine to the cliff'-line has caused a curious feature. In two places 

 between High Stacks and Selwicks the sea, which here assails the cliff 

 far more violently than on the sheltered southern shore of the pro- 

 montory, has driven caves through the firm flinty chalk of the outer 



