170 
LAMPLUGH : GLACIAL BEDS. 
which the bottom of the " Basement " clay has been clearly 
seen, it is impossible to correlate this bed with any elsewhere, 
and equally impossible to say whether it is merely a local 
patch, belonging to the so-called " Basement" clay, or is 
really an older clay ; but at Dimlington, south of "Withern- 
sea, where the thick " Basement " clay is seen in the cliff, the 
great depth which must occur between it and the chalk, which 
is far beneath the surface, renders it quite possible that there 
may be other glacial beds between them, older than this so- 
called "Basement " clay. If this be not the case, the "Base- 
ment clay " must be here of immense thickness. 
The Bo alder clay overlying this Brown band I imme- 
diately identified as being the same, in all respects, as the 
" Basement " clay at Bridlington and elsewhere. It was of 
a bluish tinge, and contained a considerable quantity of 
chalk. It also contained many shells of the same species as 
those found by me at Bridlington. But besides the shells, 
which were scattered indiscriminately through the clay in the 
same way as the boulders, and were generally broken, there 
were also some curiously-twisted streaks, formed in part of a 
fine blue clay, free from stones, and in part of a dark clayey 
sand. These streaks contained many shells, Cardita borealis 
being particularly abundant. Nearly all these shells were 
crushed, and the fragments somewhat separated, as though 
through the shearing of their clayey matrix. These streaks 
have their exact counterpart in similar, though more con- 
siderable, patches at Bridlington, which form outliers to the 
shelly mass long known as the " Bridlington Crag." They 
are probably the remnants of an old sea-bottom of sand and 
mud which the ice- sheet has almost obliterated, and from 
which come the shells now seen in this Boulder clay. 
I do not know that this clay can be seen in the cliff any- 
where in Filey Bay, and had I not witnessed this exposure, 
I should have remained ignorant of its presence there. It 
