Detailed documentation and interpretation is given of a thin band of limestone nodules in the Lower Lias of Dorset, which has been subjected to early lithification, exhumation on the sea bed and incrustation and boring by organisms in a more turbulent and shallow‐water regime than that of deposition. Final burial has been followed by extensive pyritization. The stratigraphical gap during which these events took place is less than two ammonite zones.