The southern Bathgate Hills, in the eastern part of the Midland Valley basin of Scotland, were the site of a volcanic rise during late Dinantian to early Silesian times and a sequence of basaltic lavas and tuffs up to 600 m thick accumulated. The volcanic pile interrupted the regional sedimentary deposition, which involved a cyclical sequence of marine limestones and mudstones followed by estuarine, lagoonal and deltaic clastic deposits. During the Brigantian Stage of the Dinantian, freshwater terrestrial environments developed locally on the volcanic rise between eruptive phases, but later in the Brigantian the rise was transgressed by marine limestones. Intermittent basaltic eruptions continued into the Amsbergian Stage of the Silesian, accompanied by intrusion of high-level alkaline doleritic sills and associated with strata-bound Zn—Pb mineralisation. Folding later in the Silesian was followed by the intrusion of a suite of quartz-dolerite sills and dykes. These latter were commonly intruded along penecontemporaneous E—W trending faults. The intrusion of the quartz-dolerites may have resulted in remobilisation of earlier strata-bound mineralisation into epigenetic veins.