The Coal Measure clays of Shropshire are noted for the manufacture of red roofing tiles, especially in the neighbourhood of Broseley.
Agriculturally, the Coal Measure clays are usually poor, but are occasionally of good quality. The shales produce heavy, cold clays and the yellow subsoil produces soils of a light, hungry character so that the two should, if possible, be mixed together.
Permian clays are of little value except for the manufacture of red building bricks. The Nottinghamshire Permian clays make excellent roofing tiles, flower pots and red bricks.
Agriculturally, the Permian clays are a free working loam yielding large crops of most of the ordinary farm products.
Triassic clays are of great importance in the Midlands, those upper portions of them known as the Keuper Marls being much used for the manufacture of bricks.
They are specially known amongst clayworkers as the material from which the Midland red bricks of Nottinghamshire and Leicestershire and the Somersetshire tiles are prepared.
Jurassic clays are an important group, of marine origin, occurring in close association with limestone. For this reason they form a valuable source of material for the manufacture of Portland cement, but are of less value to the brick and tile manufacturer. The Jurassic System contains so large a variety of clays, of such widely different ages and characteristics, that no general description of them can be given in the present volume.
