LAMPLUGH : GLACIAL SECTIONS NEAR BRIDLINGTON. 293 
is first especially necessary to find out what relationship exists 
between the upper members of the series in the two regions. 
Another point worthy of attention in our section is the great 
irregularity of the upper surface of the Basement Clay and the 
absence of the stratified bed seen to overlie it in the cliffs to the north 
and to the south. The question arises whether this is due to unequal 
deposition or to erosion, and to this question it is difficnlt to give a 
decisive answer, though I think the evidence favours the view of unequal 
deposition. The shearing of the cracked boulder at the top of the Base- 
ment Clay, shown in fig, 2, indicates that there has been sliding pressure 
applied to the surfjice of the bed such as might well effect erosion, 
and the character of its junction with the Purple Clay in the adjoin- 
ing section (see fig. 1, Part I.) seems to show a considerable disrup- 
tion of its surface, so that stratified beds may have existed and have 
been afterwards removed. But on the other hand the Laminated 
Clay seems always to have been a low -level deposit, for on neither 
side of the town does it rise above the level of the highest tides, and 
when favourable circumstances enabled me to trace it towards 
Sewerby, it appeared to pass into chalky gravel and stratified stoney 
boulder-clay when it left the beach. It cannot, therefore, be used as 
evidence of wide-spread aqueous denudation and deposition at this 
period. The Yorkshire Boulder-clays were evidently deposited very 
unequally, being piled up in one place and scarcely developed at all in 
another, and they must have been left with an extremely irregular 
and uneven surface. This has no doubt in some cases been intensi- 
fied by later erosion, but the drainage of Holderness since the glacial 
period has been so sluggish that the erosive work performed by it 
cannot have been great. 
Whether it be believed that the Basement Clay is the product 
of land-ice or of floating-ice, it is very evident that in either case the 
current which deposited it came down from the northward or north- 
east. On the north side of Flambro' Head, as shown by certain very 
interesting surface-contortions in the chalk near Selwicks Bay, its 
course seems to have been from almost due north ; but on the south 
side it may in places have been from nearly due east, and at Bridling- 
ton Quay from the north-east. In studying the drifts of the headland 
