CLARK : GLACIAL SECTIONS. 
435 
one of the centre pits, 7^ feet below the ground level. Six inches 
from its upper edge is a band of black clay. The bed is highest 
on the S. side of the S. platform-cellar, where its appearance is 
shown by Photo. V (Plate XXIII., Fig. 3). 
The black boulder clay, it will be noticed, arches more 
steeply on the E. than on the W. side. At the base a second, 
and thick band of the same pure black clay is exposed, as well 
as in the horizontal section along the floor. After this the 
sand begins to sink again, being met at a lower level in the next 
section, the purple clays again closing over the black. 
In the X, and mid platform-cellars, a second bed of boulder 
clay rested against this red, but disappeared at the surface before 
the S. platform-cellar, so that the succeeding bed of purple boulder 
clay met the first, the two, however, thinning out slightly as they 
proceeded across the S. platform-cellar and large cellar. In the 
S.E. corner of the latter appeared black clay, purple clay, both 
with boulders and sand, the first two being reversed on the other 
side of the sand and thining out rapidly above. Thus the sand is 
united to the next bed of sand, of which, indeed, it was only a 
contortion. For this succeeding bed was a series of remarkably 
contorted sands, the twists being shown by lines and masses of 
the same unctuous, black clay seen in Photo. V. Where first 
seen at its M .W. end in the N. drainage trench it presented a 
dome of sand leaning over towards what we have called the 
central axis of Photo. V. Its varied character is shown iu Photos. 
1. to IV. I. is from the N. side of the N. foundation trench. 
Here the top of the dome has already risen above the levelled 
surface. A large scratched limestone boulder lies in the purple 
clay above it. In Photo. IV. the bed is seen at its best. Here, 
especially, micaceous lines and lines of grit help to show the 
contortions ? elsewhere there are also lines of coal dust. In the 
cellar floors the sands occupy a much larger area. The disjointed 
pieces of black clay, specially well show at Photo. IV., must have 
formed a continuous band. Further beds of sand and red clay 
