gradient of 1 in 25 in that part. Only 48 feet in height is shown in
fig. 23. The sketch is to natural scale; so that the angles of the
escarpment of chalk are not exaggerated.
Fig. 23.—Section in Crayford Pit.
Fig. 24 is a view near the curved line E F, of the eroded surface
of the chalk (A), with rearranged Thanet sands (B) 4 or 5 feet thick.
Fig. 24.—Section in Crayford Pit.
enclosing large flints from the basement-bed. The deposition of
6 feet of coarse flint-gravel (C), on the bed B, in a hollow of the chalk
excavated prior to the gravel-period, is well exposed just where the
tramway cuts through it.
The brick-earths above the gravel have been excavated. The brick-earth generally is more valuable than the sand and gravel, and the workmen often leave the lower beds in the state shown in fig. 24
