ABSTRACT
The Carboniferous, Permian and Jurassic beds at the junction of highland and lowland zones are particularly rich in minerals (Eastwood, 1964). Coalmeasures outcrop over large areas of the Upper Palaeozoic beds (1.3). Up to forty seams contain many types of coal. Workable coals are also present in the Millstone Grit and Carboniferous Limestone beds below the Coalmeasures themselves, and spread beneath Mesozoic strata as concealed coalfields, especially to the east and south of the Pennines where faulting was less intense than to the west or on the margin of the Welsh Massif. Coalmeasures even rise to shallow depths beneath later strata in western Oxfordshire (discovered in 1877) and Kent (discovered in 1895) (Hull, 1905). The scattered pockets of coal in later strata were locally important in the nineteenth century. The seat earths at the base of many coal seams, especially the lower ones, and the highly aluminous clay produced by the weathering of Millstone Grit lava in central Scotland, provide the raw material for refractory and sanitary wares; Etruria Marl for hard blue engineering bricks. Ironstone bands and nodules in Coalmeasure shales, particularly abundant in Scotland, west Yorkshire, Staffordshire and south Wales, supplied the bulk of the iron ore used in Britain until the second half of the nineteenth century. Even higher quality haematite ore was present in the Carboniferous Limestone in south and north Wales, the Forest of Dean, Furness and Cumberland, whilst the lodes of iron ore that occur as siderite or chalybite in the same strata in the Pennines, Devon and Cornwall and the pockets of haematite and other iron ores in western Scotland gave rise to brief but frantic mining activity in the nineteenth century. After the exhaustion of the Carboniferous ores the majority of home-produced iron ore was raised from the lower quality Jurassic deposits, which are particularly abundant in Cleveland, north Lincolnshire, Northamptonshire and north Oxfordshire.
