It was laid down in the shallows of the Jurassic sea and is part of the more widely defined Great Oolite Group.

In the hot, shallow sea, the water partially evaporated so that the dissolved calcium carbonate (CaCO3) was precipitated onto minute nuclei to form tiny spheres which together resemble hard fish roe.

Subsequently, the site was submerged less deeply so that the overlying Blisworth Clay was deposited in brackish conditions.

Blisworth limestone is a generally thin but widely spread deposit in eastern England.

Its exposure continues southward in a similar relationship to the Jurassic ridge, to the west of Peterborough.