The rocks beneath the greater part of the county of Herefordshire are Old Red Sandstone, which gives the characteristic colour to the local soil. These rocks originated in the Palaeozoic period as sediment laid down by rivers crossing a broad flat tropical plain. This material was the product of the gradual erosion of older rocks. The red colour is due to the presence of oxygen during the creation of these rocks - these sandstone layers have been described as the 'rust of the earth'. Although many millions of years of sedimentation formed newer strata of rocks above the sandstone, including those of the great Chalk Sea which once covered England, all of these have subsequently been eroded away. The Old Red Sandstone of Herefordshire was formed in a tropical climate south of the equator. The Ice Ages

Much, much more recently, the latest events which have shaped the landscape of the Hereford area are associated with the eight more recent of the periods of glaciation which have been taking place for the last 2½ million years. These glaciations or 'Ice Ages' were separated by periods of relatively warmer climate - the interglacials.

The most recent interglacial occurred between 128,000 to 118,000 years ago. This was the Ipswichian interglacial and was characterised by extreme variations in temperature, which may have altered by an average of 10º C within twenty, or perhaps even ten, years. Despite global warming, we are fortunate that our present interglacial is so stable.

Arthur's Stone Neolithic Chambered Tomb. The Black Mountains are in the distance. Caves at Symond's Yat in south Herefordshire have produced evidence of human activity spanning over 25,000 years. In these caves have been found stone and bone tools and the bones of species of giant deer, hyena, woolly rhinoceros and mammoth. These animals roamed a treeless tundra landscape where they became victims of the Paleolithic or 'Old Stone Age' hunters who inhabited these caves. The final extent of the last glaciation was a glacier which terminated just to the west of where the city of Hereford now stands. During this period there would have been no humans or any other mammals in the area - there was nothing to eat.

The latest retreat of the ice at the beginning of the present interglacial was quite rapid. The outwash from the melting of this glacier formed the gravel beds on which the centre of Hereford is built. The retreat of the ice left behind a treeless tundra landscape into which grazing animals and their predators, including humans, migrated. There was no sea to cross - present-day Britain was not an island at the time and the Thames was a tributary of the Rhine.