Millook Haven cliff detail 6

Detail of part of the turbidite sequence of the Crackington Formation (upper Carboniferous) at Millook Haven, north Cornwall, lit by the late afternoon sun.

This photo shows alternating sandstone (pale) and shale bands on the inverted limb of one of the recumbent chevron folds. The compass-clinometer is located on the stratigraphic base of one of the sandstone bands, which displays a fining-up sequence (in this case downwards, since it is inverted). Just to the left of the compass-clinometer, the coarser sandstone base has slumped stratigraphically down (in this case appearing up) into the underlying muddy layer (now grey shale).

This shows how you can use sedimentary structures to deduce whether the rocks are the right way up, or whether as in this case, they have been subsequently turned upside-down.