Synopsis Outcrops of Middle-Upper Jurassic rocks in northern Scotland are restricted to two sedimentary basins. In the east exposures at Brora (Sutherland) and Balintore (Ross-shire) are part of the Moray Firth basin. In the west major exposures at Staffin and in Strathaird (Isle of Skye) belong to the Minch basin. A formal lithostratigraphy is erected with five formations and twenty-six members, which have been correlated with the standard ammonite zone. Each basin presents a pair of sections, with thick sandy onshore sequences at Brora and Strathaird and condensed argillaceous offshore sequences at Balintore and Staffin. The two onshore/offshore localities show marked facies similarities, but are affected by different transgressions in the Oxfordian. A new species of Longaeviceras is described. It is the first authenticated record of this genus from the Oxfordian.