Geological Guide to Watton Cliff

The lower succession at Watton Cliff comprises of the Frome Clay Formation. Of this, three beds have been identified. In total, nearly 30m of this formation can be seen, the bulk of which (25m) are the lowest beds of the Frome Clay, the Grey Marls. Above this, a thin bed 0.84m thick has gard, fissile white marl, whilst at the top of this formation there are some 2.74m of bluish-yellow mark containing a thin band of hard white marl.

The uppermost succession is the 'Forest Marble Formation' being the most complete succession in Dorset. Here, the lowest thin bed (0.30m thick), make up the Boueti Bed where microfossils can be found. This bed is hard, sandy and stained reddish brown.

Above this is the Blue Flaggy Limestones, and blue and yellow clays. This bed is some 9.15m thick. Two thin beds can be found above this, a hard white or grey marl bed containing thin seams of shelly limestone (0.15m), and a grey clay layer around 0.50m thick, but missing at some places along the cliff.

The best bed for finding microfossils is above this, and is known as the Calcirudite (or mammal) bed. This is 3-4.60m thick and can be identified by cross-bedded shelly limestones, sandy and oolitic in places. It also has irregular clay seams and lignite.

Directly above this bed, a layer of clays with 'race', shaley limestone and thin shelley limestone with thin leaves of sandy limestone is some 6m thick with the uppermost beds of Flaggy blue limestone making the remaining 3m.