Northcott Mouth anticline - detail

A closer view of the chevron fold anticline in mainly sandstones of the Bude Formation (upper Carboniferous), just south of Northcott Mouth, near Bude, north Cornwall. The 'space' problem along the fold axis has been partly accommodated by bedding plane slippage along the more shaly bands (darker), which have 'flowed', being squeezed out along the fold limbs and and accumulating as thicker cusps in the fold crests.

The Bude Formation consists mainly of deltaic and some turbidite sandstones interbedded with shales. The sandstones are relatively thick, compared with those in the underlying Crackington Formation, and as a result, more competent.

The response to the Variscan earth movements at the end of the Carboniferous was to form more open, mostly upright or slightly asymmetric angular folds, compared with the cascades of tight recumbent folds which characterise the Crackington Formation a few kilometres to the south.