402 WALTON : SOME NEW SECTIONS IN THE IIESSLE GRAVELS. 
a well-marked line of erosion where the contorted gravel lies on the 
sand. This contorted gravel seems to show that the gravels are 
older than the boulder cla/ ; that the direction of approach of the 
ice was from the eastward ; and that the ice could rise upon the 
slope of the gravels and so surmount the abrupt face of the buried 
cliff without disturbing them, except in a few places, to any great 
depth. That the gravels are older than the boulder clay is, I think, 
also proved by the relative composition of the gravels and the clay 
with its contained bonlders. 
Details of the Sand and Gravel. 
After many hours careful search on different occasions I have 
been unable to find a single particle of any shell (except Chalk fossils) 
in either the sand or gravel ; there are no fragments showing any 
pholas or other borings ; and with the exception of one rounded 
pebble of quartzite no stones, except chalk or flint, have been found 
in either the sand or the gravel. The pebble of quartzite I myself 
found near the east end of the pit, about 20 feet from the surface, 
and a little below the reach of the contorted part. Since writing the 
above Mr. Sheppard has given me two small fragments of quartzite 
which lie found. The workmen have shown me one or two more 
small quartzite pebbles which, they said, were found in the sand low 
down, but as there had recently been a fall of boulder clay in that 
part of the pit I do not think it wise to record them. 
The microscopic examination of the sand shows that it is com- 
posed principally of clean rounded grains, with some platy and angular 
fragments. In fact on putting some of the blown sand from the 
Bridlington Cliff at the other end of the slide and comparing the 
two, I could not tell the slightest difference. 
The gravel is found both in distinct layers and irregularly mixed 
with the sand ; in several places / especially in the west and south of 
the large pit, and in one or two of the small trial pits adjoining, the 
sand forms almost the entire thickness of the strata, and contains 
only a very few fragments. The layers of gravel always have a large 
amount of sand mixed in with it. 
The gravel is composed entirely of fragments of chalk and flint, 
it is generally small in size, but a few large pieces of flint are found. 
