284 
LAMPLUFII : GLACIAL SECTIONS NEAR BRIDLINGTON\ 
local characters developed incidentally in the mass of drift deposits 
which cover Holderness. Indeed there is no doubt that it is essentially 
liable to great local changes, and that these changes are often of a 
perplexing nature ; but recent researches have satisfied me that its 
chief characteristics, its earthy or sandy texture, jts distinctive 
greenish or bluish colour, and its irregular composition, are preserved 
• over wide areas, and are sufficiently marked to warrant its separation 
from the higher clays, and to demand special explanation. 
With regard to its thickness in our section there was 15 feet of 
it in the cliff near the southern extremity, and the engineer for the 
sea-wall informed me that its base was not reached at this place in a 
boring of twenty feet below the cliff-foot. At the northern end, 
however, there was not more than four or five feet in the cliff, and 
here, fortunately, I am able to give exact information, as we tested 
its thickness during our investigation of the Sewerby Clifi* Beds 
last year by means of the boring-rods of the Geological Survey, 
which were most considerately placed at our disposal. We selected 
a spot on the foreshore where the clay happened to be conveniently 
exposed (marked by an'^', fig. 1), and there sunk through 22 feet of 
dark Boulder-clay with a few silty streaks, and reached at that depth 
fine chalky rubble or gravel yielding a little water, into which we 
bored for three feet further. This chalky stuff resembled that 
seen below the Boulder-clay in the cliff-foot near Sewwby, whence we 
traced it by means of the rods for some distance in the direction of 
our section. There is, therefore, every probability that it was the 
same bed, and that we had reached the base of the clay in our boring, 
and we may, therefore, conclude that at this place the clay has a 
total thickness of about 30 feet, and that it rests on the same chalk- 
rubble seen further to the eastward. Above it, as already mentioned, 
there is here little or no intercalary material between it and the 
Lower Purple Clay, but the junction is nevertheless so clear and 
decided that a knife might be inserted on the plane of separation. 
But both north and south of Bridlington Quay, as soon as the 
Basement Clay sinks below sea-level, we find stratified beds making 
their appearance at this horizon, consisting, as shown in my previous 
papers (Pt. I., fig. 2, and Part II., fig. 1), of a thickish bed of finely- 
