Nibley Knoll (grid reference ST744956) is a 3.2-hectare (7.9-acre) geological Site of Special Scientific Interest in Gloucestershire, notified in 1974.

[2] The site is in the Cotswold Area of Outstanding Natural Beauty and is a significant geological location which shows a thick section of Lower and Middle Jurassic rocks.

The section above, which is the Cephalopod bed (top of the Aalenian Stage), is similar to the exposures on Wotton Hill.

The Lower Inferior Oolite Freestones, are topped by 'hardground', which is a thin layer of tough limestone which is encrusted with fossil mollusc shells.

There is an absence of Middle Inferior Oolite as a result of the effect of an important phase of uplift (warping) of the crust during the Lower Bajocian time interval.