East Anglia is not a rocky part of the country, but the lack of crags and mountains does not mean that it is uninteresting from a geological point of view. The Fens to the west of the county of Norfolk were, until drainage changed wet lands to rich agricultural land, expanses of water and marsh. This drainage can be traced back to Roman times, but it really got underway in the 17th century when Dutch engineers introduced extensive dykes and wind pumps. Bog oak, which is still regularly turned up in the subsoil, is a feature of the Fenland. This wood can be thousands of years old, but it is not fossilized, having been preserved by the acidic peat bog surrounding the fallen timber. The anaerobic conditions and tannin rich water kept the wood from rotting. It is very hard and dark in colour.
From Neolithic times Grimes Graves near Brandon in Suffolk has been recognised as the source of the best flints for working into tools. Even in my lifetime there were still flint knappers working in Brandon, making gunflints which were used in remote corners of the empire. Flint is the commonest stone found in East Anglian, and has not been widely used since the Bronze Age produced metal for making edged tools. The necessary copper ore was not found locally, but iron ore is found in places in East Anglia, and was used for smelting in the Iron Age. Stones of interest include iron rich carstone; strata including carstone appear in decorative contrast in the cliffs of Hunstanton. Carstone is used extensively in West Norfolk as a building material, now as an expensive feature, but in the past as the natural local choice. Slightly further round the coast hard chalk – clunch – is used very locally as a building material at Thornham and nearby. In Suffolk the honey coloured stone septaria is available in sufficient quantities to form the building material for the bulk of Orford castle.
Much of the Norfolk coast is made up of sandbanks and saltmarsh. The Holt Cromer ridge is where the cliffs appear to the east of Weyborne, and extended to Paston near Mundesley. To the west the coast is mostly marshes and sand-dunes. These cliffs contain the highest ground in Norfolk at Beeston ‘Bump’ and are the terminal moraine of the advancing glaciers which deposited their debris at the edge of East Anglia during the last ice age. There were several ice ages in the past, which affected East Anglia –proof that there is nothing new about climate change! It has been going on for millions of years. The global warming that followed these ice ages can have owed nothing to fossil fuel use. I am not disputing the current man-made increase in CO2 and its possible result in rising temperatures; I just wish to point out that not all climate change is down to human activity.
All along the East Anglian coast, from Snettisham to Southwold, among the beach pebbles one may discover the translucent semi-precious gemstones known as carnelians. East Anglia is particularly rich in these stones. A hoard of unmounted but engraved carnelians dating from approximately 155 A.D. was found in Snettisham in 1985. This hoard once belonged to a Roman jeweller; it includes finished and unfinished gems. There were over one hundred of the gems awaiting completion, when for some unknown reason they were hidden and never retrieved.
The geological interest now switches from rocks to fossils. West Runton is famed for revealing an elephant during the 1990s. This 10 ton mammoth is about half a million years old. Further along the coast at Trimingham the marl cliffs have huge numbers of belemnites which constantly fall into the sea. Also found are fossilized sea urchins and ammonites. All along the north-east coast of Norfolk, when the tides scour the shore, the stumps of ancient trees are revealed; unlike the bog oak these trees are fossils. When these trees were growing, England was joined to the continent and the mouth of the river Rhine lay in the heart of what is now the North Sea. The Thames and all the rivers as far as the Yare were its tributaries.
THE BLOG FOR THE STORY OF EAST ANGLIA