Old Red Sandstone
The Old Red Sandstone is a large group of rocks of late Silurian and Devonian age. They were formed in a semi-arid desert environment which has given them their conspicuous red colouring through the intense weathering of iron-bearing minerals. Nevertheless, they are highly variable in outcrop with red, green, purple or brown colourings, coexisting in many cases.
Sandstones, mudstones, calcretes and conglomerates (both pebbly and intraformational) are interbedded with one another as a result of deposition in seasonal, shifting, braided rivers. Sandstones form the best and most widely used building material with calcretes and cornstones generally used only very locally and most likely as a by-product of lime burning.
Generally used quite locally, it is the most important building stone across most of Herefordshire. The variable nature of the stone can give very local character to individual villages.
Particularly notable areas of use include the Golden Valley, the Bromyard Plateau, Ross-on-Wye and the Teme Valley (for instance the village of Clifon upon Teme) however they are extremely ubiquitous across the area of their outcrop.