390 
LAMPLUGH : GLACIAL SECTIONS. 
very few signs of disturbance. It contains a few very small 
fragments of marine shells — such only as might have been deriv- 
ed like the drift pebbles from the washings of a boulder clay. 
The Purple Boulder Clay (3) is a hard, tough boulder clay of 
dark brownish -purple colour* ; contains more boulders than the 
Basement Clay and they are generally larger ; has an occasional 
marine shell fragment, worn and sometimes scratched, and probably 
a mere pebble. The disturbance of its upper part has already 
been touched upon ; the sides of the steep hollow between C and 
D in section 1 showed slickensides, and their bases were grooved 
into deep steps. The protruding masses also in some cases ex- 
hibited the same signs of movement, and some detached patches 
of laminated clay included in its base near A showed similar symp- 
toms. Indeed, throughout section 1 this clay seems to have been 
disturbed to a great depth; near C the upper eight feet appeared 
to have slid over the dome shaped masses below, and the top of it 
was arranged in thick plates which did not look like bedding. At 
the southern end of the section there is great confusion ; isolated 
patches of gravel and sand, probably of two or three ages ; of 
laminated clay ; and of the Basement Clay, were all mingled 
with the Purple Clay in a manner far too intricate to be faithfully 
rendered on a small scale. 
In section No. 2, a little distance be3 r ond Sands Cottage 
the Purple Clay divides and admits the gravel 2a, as has already 
been described. The upper band, 3a, has suffered severe erosion, 
and is cut and dragg-ed much in the same way as the top of the 
clay in No. 1 , but not on so large a scale. In one or two places 
it is broken quite through, and then the red tinge of the upper 
gravel spreads into the lower. I have already referred to the 
doubt as to whether this upper band may not represent the newer 
* The attempt to describe in words the mixed indefinite tints of such 
beds as these is very futile. In most cases the description fails to convey- 
any clear impression to the reader unacquainted with the bed, or gives him 
an erroneous idea. They are only of use as comparing one bed with 
another. 
