Geology

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 Devonian period, 400 to 350 million years ago. The sediments of which the old red sandstone is formed came from the erosion of a range of mountains which included parts of Scandinavia and Scotland, together with the Catskill Mountains in what is now North America. These sands were then laid down by rivers crossing a broad flat semi-arid tropical plain to the south of the equator. 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'.

The Old Red Sandstone of Herefordshire was formed in a tropical climate south of the equator.

Although many millions of years of sedimentation formed newer strata of rocks above the sandstone, including those formed in the Cretaceous period by the great Chalk Sea which once covered England, all of these have subsequently been eroded away. The Cretaceous period was the last one in the Mesozoic (middle life) era.

Most of the named divisions of geological time are named from the fossils found within the rocks of the Cambrian period. There was a growth in the number of fossils representing the sudden appearance of many groups of animals. The Cambrian was the earliest bit of the Phanerozoic eon. The name Phanerozoic derives from Greek and means visible life. It is the eon in which we live and has lasted for about 545 million years.

The Phanerozoic eon is sub-divided into the Palaeozoic, Mesozoic and Cenozoic eras.

The Palaeozoic

Palaeozoic means 'old animals', and is named from the fossils of ancient animals founds within its rocks. The earliest rocks in the series were first identified in Wales and so the ancient name for Wales - Cambria - is used for them. The Cambrian was followed by the Ordovician (named for the Ancient British tribe of central Wales) which saw the replacement of many of the life-forms of the Cambrian with newer ones. This seems to have followed a major extinction event - the Cambrian-Ordovician extinction.

Another Ancient British tribe, the Silures of south Wales, gives the name Silurian to the third division of the Palaeozoic. It was during the Silurian that life, in the form of mosses, colonised the land.

The Herefordshire Lagerstätte - it is from the Silurian period that some of the most interesting fossils found in Herefordshire come and they are international importance. This group of invertebrate animals were living on the bed of the ocean 425 million years ago when they were killed and buried, and finally preserved by, a sudden fall of volcanic ash.

One of these small animals was a previously unknown arthropod, which was given the name Cinerocaris magnifica. Another previously unknown species was Acaenoplax hayae, known to the discoverers as 'the spiny worm'. Acaenoplax is a type of mollusc, therefore in the same phylum as squids, slugs and snails. There was also a species of Bdellacoma, a genus of starfish and early barnacles. The area that these fossils were found in is one of the few parts of the county where the later Devonian rocks have not buried the Silurian formations.

One of these areas is the Woolhope Dome, a geological anticline where rocks of the older, Silurian period, form an island within the Old Red Sandstones of the Devonian. At Hough Woods the oldest rocks of the Silurian come to the surface, these are the rocks of the Llandovery series and were deposited world-wide 444 to 428 million years ago. In decreasing age the rocks surrounding this formation are the Woolhope, Much Wenlock and Aymestrey limestones which form the concentric scarps of the 'dome'.

Herefordshire rocks of the old red sandstone near Ross-on-Wye. For many millions of years these rocks were covered by later rocks which were then eroded away. Glacial outwash gravels have covered these rocks in the area of the City of Hereford.

The Devonian was followed by the Carboniferous, which takes it name from the coal beds which for many years were its most significant economic characteristic. It is the period in which primitive conifer trees made their appearance. Generally rocks of this period are absent from Herefordshire -  less than 1% of the county’s surface area is carboniferous rock- but in the Symonds Yat area Devonian Old Red Sandstone is overlain with strata  of the Carboniferous Limestone Series.

The final period in the Palaeozoic is the Permian. The name was given to this period by Sir Roderick Impey Murchison after the ancient kingdom of Permia, not after the Russian town of Perm.  It was during this period that the first fully terrestrial animals evolved. The Permian period, and the Palaeozoic era, ended with the greatest extinction event known- the Permian-Triassic extinction event. in which over 90%  of marine species and perhaps70% of land species became extinct. Permian rock formations are absent from the area of Hereford but outcrops in Worcestershire as the geological strata of England slopes downwards from west to east: the oldest rocks are on the surface in the west where the younger rocks have been eroded from above them.

The Mesozoic

Mesozoic means 'middle animals', and the era is sometimes known as the 'Age of the Dinosaurs'. At the beginning of the Mesozoic almost all the land on earth formed a single continent, known to geologist as Pangaea which gradually split up, so that by the end of the era, the continents that we now know were formed.

The Cenozoic

the Neogene

The Miocene was the first epoch of the Neogene. Warmer than those in the preceding Oligocene or the following Pliocene, it saw the expansion of grasslands and the creation of kelp forests.

The second Neogene epoch, the Pliocene, saw global cooling and the enormous spread of grasslands encouraging the proliferation of grazing mammals. Ice began to accumulate at the poles. This would lead to the ice ages.

It is only in the third and fourth epochs of the Neogene, the Pleistocene and the Holocene that humans began to inhabit the Herefordshire landscape.

The Ice Ages

The most recent ‘hard’ geology in Herefordshire is the Carbiniferous rock formations of the Symonds Yat area. Much, much more recently than the Carbiniferous, the latest events which have shaped the landscape of the Hereford area are associated with the more recent of the periods of glaciation which took place during the Pleistocene. These glaciations or 'Ice Ages' were separated by periods of relatively warmer climate - the interglacials. It was during the Pleistocene that early humans first came to the area which is now Britain.

Lower Palaeolithic

About 700,000 years ago what is now Britain was a peninsula of mainland Europe and human-type creatures were living at Pakefield, Suffolk. Only their tools have been found so we cannot be sure what type of people they were, but at Boxgrove in West Sussex archaeologists have excavated 500,000 year old human remains. The Boxgrove people were Homo Heidelbergensis and are found in both Africa and Europe. These are ‘hominids’ and were probably ancestral to both Neanderthals and Homo Sapiens. This period is known to archaeologists as the early or ‘lower’ Palaeolithic.
 

The major river of southern Britain in this period is known as the Bytham. This ran eastwards through the southern midlands and East Anglia and what is now the North Sea but was then dry land. Stone tools found along its course suggest that this was the route that the earliest inhabitants followed into the Midland area.

The Thames followed a slightly more northerly route than it now does and another river, the Mathon, flowed south through Herefordshire.

About 450,000 years ago an Ice Age known as the Anglian glaciation totally obliterated the Mathon and Bytham river and diverted the Thames further south. The Anglian glaciation was followed by the Hoxnian interglacial (425,000 – 380,000).  Although thousands of hand axes and other stone tools have been found in southern Britain suggesting widespread occupation at this time, there is very little evidence from the Midlands.

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.
 

Upper Palaeolithic

Caves at Symond's Yat in south Herefordshire have produced evidence of prehistoric human activity. 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 Palaeolithic 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.

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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.

By about 7,500BC temperatures had risen to an average of several degrees higher than today. The River Wye had established something approaching its modern course and trees began to appear in the central Herefordshire plain. There has been a tendency to over-estimate the density of woodland in this period; it seems likely that the thick forests of popular imagination never existed and that there was always much open grassland.
 

The divisions of the Palaeolithic (the old stone age)

Palaeolithic

Mesolithic

In 2001, a small group of Mesolithic flint tools was found during an archaeological excavation in the centre of Hereford.  Although no structures were found, these finds may indicate that there was a habitation site in the immediate area.  The Mesolithic was the period in which human beings first re-occupied land from which the ice had retreated, moving into the area before Britain was an island.  It was these people who would form the bulk of the population of the area until the present day.

It used to be thought that Mesolithic people were nomadic, but recent archaeological evidence suggests that in Britain some at least were living in permanent houses by 7500BC.  Any settlement at Hereford would have had access to all the resources it needed to support a relatively comfortable life.  The people would have gathered a range of food which grew naturally in the neighbourhood – nuts, roots and fruit.  They would also have hunted birds, deer, wild pigs, hares (there were no rabbits) and other mammals.  Nearby, fish were available in the River Wye.  Not all wildlife was harmless of course: wolves might have posed some risk to small children, and hunting wild boar was certainly dangerous for adults.  There were bears in the Mesolithic woods.

The Palaeolithic to the end of the Bronze Age in Britain

Neolithic

Agriculture originated in the Fertile Crescent - Palestine, Syria and Iraq - and gradually spread west into Europe, and this introduction of farming as a way of life defines the beginning of the Neolithic period. It was probably not brought about by a movement of people but rather by a diffusion of culture which changed the diet of the population with surprising rapidity.

What is missing from sites of this period in Britain is much evidence of large-scale processing of grain, once thought to be the mainstay of Neolithic populations. There is some; charred bread ‘made partly of crushed grains of barley’ was found in an early Neolithic pit at Yarnton, eight kilometres north of Oxford, and grain was found in a Neolithic pit beneath what is now the Asda supermarket in Hereford. But by and large the British Neolithic diet was animal products and gathered fruits and nuts - arable agriculture made a negligible contribution to it.

There was certainly a sudden change of diet in the British Neolithic. Mesolithic people, particularly on coastal sites, consumed a lot of fish, particularly shellfish. These source of food was ignored in the Neolithic in favour of mammals. The Neolithic inhabitants of Britain were herders, usually of cattle, but perhaps of sheep in some areas.