In the Inner Hebrides the Gribun Conglomerate Formation (possibly Maastrichtian in age) lies above the Cretaceous Chalk and below the Palaeocene basalts. It is best developed on the Island of Mull, but is also found further north in Skye. The Gribun Formation and the Chalk record several episodes of widespread silicification during the Late Cretaceous and possibly again very early in the Palaeocene. This silicification is evidence of arid or semi-arid terrestrial conditions. The possible absence of Campanian sediment may have been caused by magmatic underplating.