109 - Midvale Ridge : Description

Physical and functional links to other National Character Areas

Midvale Ridge National Character Area (NCA) is completely enclosed by the surrounding Upper Thames Clay Vales NCA and offers wide views across the adjacent countryside from many points. In places it is possible to see the hills of the Chilterns NCA to the south-east, the Berkshire and Marlborough Downs NCA to the south-west and the Cotswolds NCA to the north-west.

At Oxford, the Thames cuts through the ridge to flow south from its source in Gloucestershire on towards Reading and London. The Thame, a tributary of the Thames, flows along the lower reaches of the ridge in the south-eastern half of the area and joins the Thames just south of Dorchester. Much of the ridge functions as a minor aquifer, eventually feeding into the rivers Thames, Thame and Ock, also a tributary of the Thames.

To the east, several major transport links between London, Oxford and the Midlands, including the M40, A40 and the Chiltern Railways line, cross the area. Although part of the city of Oxford lies within the NCA, the historical centre is in the neighbouring Upper Thames Clay Vales NCA. Many of Oxford’s most notable buildings, for instance the Radcliffe Camera, are built from stone quarried on the ridge. To the west, the Great Western Community Forest stretches from Royal Wootton Bassett in the Upper Thames Clay Vales NCA to Faringdon. (Groundwater Quality Review: The Corallian, Environment Agency, April 2004)

The Midvale Ridge today

The Midvale Ridge is a low-lying, irregular outcrop of limestone rising as a distinctive feature above the surrounding flat clay vales, running westwards from the Vale of Aylesbury to Swindon. Tabular hills at its eastern end give way to a thin ridge that in some places is low and narrow, but in others stands out as a striking feature. In all directions there are sweeping views across the adjacent countryside.

The Thames cuts a steep valley at Oxford to flow south across the ridge and the Thame flows along its south-east edge. Springs and streams rising on the ridge drain into the rivers Ock and Thame. The bedrock of the NCA is very porous and much of the ridge is a minor aquifer.

The area is mainly agricultural and the landscape is one of arable fields or pasture interspersed with woodland and many small settlements. Fields are generally large and rectilinear, mostly resulting from late 18th- and 19thcentury enclosure and re-organisation as well as later agricultural changes, with boundaries of hedgerows and regularly spaced hedgerow trees. A mix of heavy rendzinas, stagnogleys and lighter sandy brown earths with small areas of sandy soils form the main soil types.

The ridge has good tree cover. On moister soils, particularly around Oxford, ash, oak, hazel and field maple are common. Elsewhere, on the drier soils across the ridge, the characteristic tree types are oak and birch with significant plantations of conifers. To the east of Oxford lies Shabbington Wood, the largest surviving remnants of the former Royal Forest of Bernwood, important for the rare black hairstreak butterfly. While significant parts were managed as conifer plantations, most are now being managed to gradually return them to predominantly broadleaved woodland. Around Swindon, several new plantations of woodland have been established as part of the Great Western Community Forest project, one of 12 Community Forest projects set up across the country with the aim of regenerating areas of land in the urban fringe for recreation, biodiversity, forestry and socio-economic benefits.

On the lower slopes, where the permeable limestone meets the impermeable clay of the surrounding clay vales, water percolating through the limestone emerges in a series of springs and flushes. These support several large fens which are home to a number of rare plant and invertebrate species such as the narrowleaved marsh orchid and the southern damselfly – both nationally rare. The largest fen, Cothill Fen, has been designated a Special Area of Conservation (SAC) for its alkaline fen vegetation.

To the south-west of Oxford, around Frilford and Cothill, are areas of calcareous grassy heaths comprising one of the most characteristic and important semi-natural habitats of the Midvale Ridge. These were once more extensive but are now greatly diminished and fragmented in character but still provide a home for several rare species of solitary bees including the girdled mining bee and the six-banded nomad bee as well as uncommon plant species such as the grass of Parnassus. Although small, the NCA is host to other areas of uncommon habitat including dry acid grassland and the only area of heathland known in Oxfordshire.

Hill top villages are a distinctive feature of the ridge. They are often clustered round a village green and are linked by small sunken lanes enclosed by low hedges. To the east, houses are built of the local limestone or sometimes red brick and timber frame with thatch or tiled roofs. In contrast, to the west houses are typically of local limestone, either Cornbrash or Corallian, with stone slate roofs. Settlements have also grown up along springlines. Isolated farmsteads mostly result from late enclosure.

The past is reflected in the landscape with the remains of Roman settlements still visible and the nationally important examples of ridge and furrow ploughing at Ashendon, Dorton, Quainton and North Marston. Windmills are a characteristic feature of the area and can be found throughout the ridge top.

Notable buildings include the barn at Great Coxwell, built at the height of the arable expansion and population growth of the 13th century, and the 19th-century manor house at Waddesdon designed by the French architect Gabriel- Hippolyte Destailleur.

The landscape through time

The Midvale Ridge was laid down mainly during the Upper Jurassic, about 157-146 million years ago, when sands and limestones were deposited in what was then an area of coral reefs in a shallow tropical sea. Fossils found locally are evidence for an abundance of marine life in the area at that time, including many species of ammonites and marine reptiles such as plesiosaurs and ichthyosaurs. Over time the softer clay of the surrounding Upper Thames Clay Vales NCA eroded more quickly than the limestone of the ridge, leaving it today as a prominent feature. Watercourses have since laid down layers of clays, silts, sands and gravels and small areas of peat developed around the fens.

Evidence for the first significant occupation of the area during the Bronze Age is seen, for instance, in possible bronze-age round barrows found across the area, including those at Buckland. Occupation continued into the Iron Age and the Romano-British period with settlements such as the Romano-British temple complex, villa and amphitheatre at Frilford,

Oxford first developed during the Anglo-Saxon period as a fording place. From the 6th to 9th centuries the area was disputed between the Anglo-Saxon kingdoms of Mercia and Wessex with the Thames eventually forming the boundary between the two. In the early 10th century, the town was fortified to resist the attacks of Danish invaders, becoming part of the burh system established to defend Wessex. From the 13th century onwards, the university colleges were established and Oxford’s international reputation as a place of learning grew.

Throughout the region in the Middle Ages the open field system of agriculture was widespread and ridge-and-furrow earthworks can still be seen, particularly in the eastern half of the region. Enclosures and reorganisation of farmland during the 18th and 19th centuries saw the introduction of large regular fields. The area is described in Domesday Book as being well forested but in a national context the extent of woodland cover was probably low at that time. Bernwood Forest, remnants of which are still extant in the eastern half of the NCA, was a popular hunting spot for Anglo-Saxon royalty and following the Norman Conquest attained the status of a Royal Forest. The area subject to forest law was reduced over time and Bernwood Forest finally lost its legal status in 1632. The removal of legal protection also saw the reduction in forest cover.A number of windmills, such as that at Brill, provide distinctive landmarks throughout the area.

Industry has also played an important part in the area’s history. The clay deposits at Brill provided the material for a pottery, brick-making and tile industry.Corallian Limestone was quarried at Wheatley from the 12th century and at Headington from the 15th century. In the 16th and mid-17th centuries, Oxford was famous for its tanning and woollen industries. In 1624, an Act of Parliament allowed navigation to be improved on the Thames between Burcote and Oxford and by 1790 the Oxford Canal was opened, linking the city to the rest of the canal network. During the 19th century, Oxford developed as a centre for light engineering, particularly for agricultural tools. The first steam rollers and ploughs were invented by John Allen of Oxford. The association with engineering continued with the founding of Morris Motors at Cowley in the early 20th century. The motor industry continued to be an important employer.

Prior to the 19th century, Swindon had been a small market town. It was boosted by the opening of the Wiltshire and Berkshire Canal in 1810 and the North Wiltshire Canal in 1819 but the arrival of the Great Western Railway in 1840 and the subsequent decision to site the company’s works there provided a spur for rapid growth. Until the early 20th century, it remained the city’s largest employer.

The M40 was constructed between 1967 and 1974, later being extended to link London and Birmingham.

A History of the County of Oxford: Volume  – The City of Oxford, Alan Crossley and C.R. Elrington (eds), Victoria County History (1979)

Buckinghamshire County Council website (URL: http://apps.buckscc.gov.uk/eforms/ medieval_life/history1.htm)

Brill: Historic Town Assessment Report, Consultation Draft, English Heritage (undated) A History of the County of Oxford: Volume 4 – The City of Oxford, Alan Crossley and C.R. Elrington (eds), Victoria County History (1979)

A History of the County of Wiltshire: Volume 9, Elizabeth Crittall (ed.),Victoria County History (1970)