The photograph shows a core sample from a borehole drilled at GR 871 314. This is an example of an evaporite deposit.
Such rock types are never preserved in surface outcrops in this area. Why is this?
Scale: scale bar is marked in 1 cm divisions.
Grid reference: 871
314. This is the position of the top of the borehole. Unit P22 is not
at the surface here.