Anglo-Saxon Romsey
The Evidence in the Landscape
The Geology of the Lower Test Valley
The study area for the Anglo-Saxon project included parishes surrounding Romsey on either side of the Test valley. Most of this area lies within the Hampshire Basin, a large geological depression. The down-folded strata within the basin are made up from material deposited by ancient rivers, consisting mainly of gravel, sand, silt and clay. This basin extends west beyond Poole Harbour and east into Sussex and is bordered on the north by Cretaceous chalk. Its southern rim runs east-west through the centre of the Isle of Wight where it appears as a prominent landmark, The Needles. The underlying geology has a significant impact on the appearance of the landscape and on the lives of the people living in it. This was particularly the case in past centuries when people relied on their local environment to supply their basic needs for daily life.
A satellite image of the drought-stricken landscape in the summer of 2022. North of the Isle of Wight the colours of the parched fields have mapped the bedrock geology. The yellow-brown chalk outlines the arc at the northern edge of the Hampshire Basin.
The chalk at the southern edge of the Hampshire Basin forms The Needles on the Isle of Wight. Less dramatically, its northern edge is visible as the higher ground on the horizon looking north from Hillier Gardens over the valley of the Fairbourne.
Photos by Karen Anderson
3D Google satellite image with modern surface water. The view extends from the valley of the Test on the left to the Itchen on the right. The tributaries of the two rivers flow west, south and east, draining this section of the Hampshire Basin. The topography changes on the Chalk geology with the rising ground at the rim of the Basin. The map is tilted slightly, foreshortening the view. It covers an area 8.5 miles wide and 7 miles north to south.
Google satellite image of the lower Test and Itchen Valleys with surface water added. The two rivers flow into Southampton Water.
The parishes in the lower Test valley mapped along with the river systems. The Test with its multiple channels runs from north to south through the centre. Parishes lacking streams lie on the Chalk.
The Test divides the study area into two parts. The river has created a wide valley, appearing on the map as a complex network of channels, many of them man-made or man-managed. The water traces very different patterns either side of the Test. Two tributaries enter the Test from the west. The Blackwater, to the south running through East and West Wellow, has a large catchment area with numerous streams draining rainwater from the gravels. Further north the Dun flows through East and West Dean, Lockerley and Mottisfont. This stream flows along a small syncline, a down-folding of the underlying bedrock. This geological structure lies near the edge of the Hampshire Basin, another, larger, syncline. The two are separated by a chalk ridge which forms Dean Hill. The place-name Dean comes from the Old English word denu meaning a valley, an appropriate name for a distinctive, wide valley formed by the erosion of the softer sediments flanked by chalk bedrock. The Dun receives much of its water from springs. Chalk acts as an aquifer, a reservoir of groundwater. Rather than draining from the surface and feeding directly into streams, rainwater percolates into the chalk bedrock and is stored in a network of fractures. This water flows along the fracture lines and emerges downslope as springs. Streams fed by chalk springs tend to have a stable flow with the chalk regulating the water supply. Heavy rainfall on chalk will not result in flash flooding on its rivers. Having a consistent and reliable supply of water, chalk streams like the Dun and the Test were valuable sources of water power for driving mills. The Anglo-Saxons undertook extensive engineering projects to harness the Test for their mills.
The drainage pattern on the east side of the Test is very different from that on the opposite side of the valley. Here the Test has only two small tributaries joining it from the east. The Fairbourne runs through Michelmersh and Timsbury on the northern boundary of the parish of Romsey Extra, while the Tadburn enters the valley on the southern edge of Romsey town. Minor rivulets flowing westwards further south have been captured by the Andover to Redbridge canal. The east boundary of Romsey Extra follows a watershed. Streams further to the east drain towards the tidal estuary of the Test or flow south into the Itchen. This north-south drainage pattern is related to the formation of a step-like series of river terraces along the Test and the Itchen during the Pleistocene, the Ice Age. This climatic upheaval shaped the landscape we see today.
The superficial geology of the lower Test valley mapped with a LiDAR hillshade image and surface water. The deposits are:
Brown - Clay-with-flints
Orange - River terrace
Yellow - Alluvium
Pink - Head
This material overlies, and is much younger than, the bedrock. It was deposited over the past 2.6 million years, from the beginning of the Pleistocene to the present.
The superficial geology deposits record the impact of the Pleistocene on the landscape. The Pleistocene began 2.6 million years ago and ended only about 11,500 years ago. The ice advanced and retreated a number of times, dividing the epoch into glacial and interglacial periods. The ice sheets did not extend into southern England. Here there would have been a periglacial environment similar to the Arctic tundra with heavy winter snow and permafrost. Warmer summer weather would thaw the surface while the subsoil remained frozen. On top of the chalk bedrock are deposits of Clay-with-flints, brown on the map. This is the residue produced by the erosion of chalk and other deposits that had previously overlain the remaining chalk. This material has been mixed and distorted by repeated freezing and thawing. The small patches of pink represent Head, a deposit that slumped downhill during the seasonal thaw to infill the valleys.
The two other main superficial deposits are related. Together they trace the evolution of our landscape through the Pleistocene to the present day. Yellow on the geological map represents alluvium, sediments consisting of gravel, sand, silt and clay deposited by a river. The presence of this alluvium indicates the extent of the current, active floodplain, the area that has been flooded by the river and is liable to future flooding. Orange represents river terrace deposits. A river terrace is a former, abandoned floodplain created when a river was flowing at a higher level. The terraces were formed by the Test and Itchen and their tributaries in response to tectonic uplift during the Pleistocene along with the fall in sea level during periods of glaciation.
The river terraces are composed mainly of flint gravel and sand derived from the chalk downs to the north, combined with reworked sediments from within the Hampshire Basin. The deposition of the large volume of material making up each terrace would have taken place at the close of a period of glaciation. Initially, meltwater formed wide, braided rivers carrying heavy loads of the sediments released from the permafrost. Rivers evolved from their braided form, with multiple small channels separated by temporary islands of gravel and sand, to a single channel. The river then cut through the sediments of the floodplain to flow at a lower level, creating a new floodplain and a terrace.
There are extensive river terrace deposits along the Test and Itchen with remnants of additional terraces between the two rivers. The terraces have been numbered from 1 to 11 according to their height, roughly correlating with their age. A staircase of terraces flanks the Test. Romsey lies on the most recent terrace, numbered 1, with a series of steps, 2 to 5, to the east, each terrace stepping back in time. A steep scarp on the west side of the Test rises to terraces 6 and 7. Romsey’s river terrace started to develop at the end of the Ice Age, 11,500 years ago. As the glaciers to the north melted, the silt incorporated in the ice was blown from the surface and deposited on the top of of the terrace gravels. Known as brickearth due to its suitability for making bricks, it provided a rich and fertile soil. With good land for growing crops and water for livestock nearby, Romsey was an ideal location for settlement.
The river terraces rising up the side of the Test valley are apparent in the topography along Cupernham Lane. Roads heading east, such as Durban Close on the left of the photo, climb the terrace steps. The houses on the west side of the lane are at a lower level, with the roads dropping down to the first terrace.
Combined superficial and bedrock geology. The superficial deposits, yellow for alluvium and orange for river terrace gravels, mask much of the bedrock between the valleys of the Test and the Itchen. The terrace on the east side of the Test is the first, youngest terrace. The broad area of terrace gravels west of the Itchen represents several levels of river terrace. The soil here was of poor quality, lacking the topping of brickearth found on Romsey’s terrace. This flat and undeveloped landscape provided the space for the development of Eastleigh and its railway works in the 19th century and Southampton Airport in the 20th century.
The first edition OS map shows the newly built railway lines crossing a sparsely populated landscape. Little Eastley and Great Eastley Farms are isolated within the fields on the river terrace west of the Itchen.
The flat river terrace provided an ideal location for the railway works and the new town of Eastleigh, shown here on the early 20th century 3rd edition OS map.
Bedrock Geology
The bedrock geology of the northern Hampshire Basin with parish boundaries, pre-1851, in red. Chalk formations are coloured in shades of green. A small syncline, a down-folding of the strata, lies on the northern rim of the basin west of the Test. An anticline, part of the Portsdown Anticline, underlies Nursling, Chilworth and North Stoneham.
The Hampshire Basin is a large syncline. The geological formations within a syncline decrease in age from the outer rim towards the centre, from north to south on the map. The formations shown on the map are:
Lambeth Group - represented here by the Reading Formation with deposits of pebbles, sand and clay mapped separately
Thames Group
Bracklesham Group
The geological sequence from older to younger formations has been altered by the upfolding of the strata, raising the Thames Group formations to the surface along the Portsdown Anticline. A shallow syncline to the north underlies Baddesley Common and Emer Bog. The nearly horizontal clay layers within the Wittering Formation impede drainage, creating an area of mire, wet woodland and grassland.
Wood pasture and grassland on Baddesley Common. The Hampshire and Isle of Wight Wildlife Trust manages Emer Bog and part of the common as a nature reserve.
Anglo-Saxon potters in Michelmersh made use of the Reading Formation clay, which ranges in colour from red/orange to blue/grey. Several kilns producing Michelmersh Ware have been excavated, one of which was still filled with pots. The colour of the pots was not determined by the colour of the raw clay, but by the conditions in the kiln during the firing. A smokey environment, lacking oxygen, reduced the iron to produce grey pots. The pots would have been red if the potter had allowed sufficient air into the kiln to oxidise the iron in the clay.
A report on the Saxon pottery kilns was published in Vol. 51 of the Hampshire Field Club journal.
Pebble beds of the Reading Formation outcrop in a field named as Popley Hill on the Michelmersh tithe map. The hill might be the boundary landmark in the 10th century Michelmersh charter - populfinige means ‘pebble heap’.
Flint nodules were moved to the edges of ploughed fields to avoid damage to the plough. These concentrations of flints are sometimes misidentified as the metalling of a Roman road, particularly where a hedge has been removed leaving a line of flints at the former field edge. Flints shattered by the impact of a plough share create flakes that superficially resemble flint tools, but lack the characteristics of a deliberately fashioned flint implement.
Bedrock geology combined with LiDAR. Much of the London Clay is heavily eroded by a network of small streams. Within the Thames Group the Nursling Sand and Whitecliff Sand Members underlie the higher ground. The Earnley Sand Formation forms much of the higher topography in the landscape of the Bracklesham Group bedrock.
Hillier Gardens extends east beyond the Romsey parish boundary to include part of Ampfield Wood. This land, bounded by the Bishop’s Bank, was owned by the Anglo-Saxon Bishops of Winchester and was probably used as a deer park. The wood is on the high ground. The photo looks north towards Braishfield across the landscape of the eroded London Clay. The Chalk rim of the Hampshire Basin is on the horizon.
Hillier's Woods of the World and the Woodland pigs lie within the Saxon deer park. A map of Hillier Gardens can be downloaded from the website:
An outline version of the 1588 Hursley estate map superimposed on the bedrock geology. The northern half of the estate lies on the Chalk. Open areas in the southeast, labelled as ‘Heathe’ on the original map, are located on the Whitecliff Sand.
The Wittering and Earnley Sand Formations of the Bracklesham Group underlie North Baddesley shown here on the 1826 estate map. The church and the various farms and cottages are located on the higher ground on the Earnley Sand.
Detail of the 1826 North Baddesley estate map with bedrock geology. The manor house with its outbuildings, paddocks and orchard is south of the road opposite the church, to the left of the map.
3D view looking south. The church is located on the edge of the higher ground with an extensive view across the landscape as far as Farley Mount, a beacon site up on the Chalk, beyond the edge of the Hampshire Basin. The site for the church and manor might have been chosen for its strategic importance.
North Baddesley church with the manor house in the background, on the opposite side of the road.
The view from North Baddesley churchyard, looking north.
The 1755 Chilworth estate map with bedrock geology. Most of the estate lies on London Clay with areas of Whitecliff Sand, with Wittering and Earnley Sand Formations to the north. Woodland covers much of the estate.
3D map of the bedrock geology with the 1755 Chilworth estate map. Parallel ridges and valleys have formed in the London Clay. Roads run along the ridges. The M27 has cut a deep scar across the landscape.
LiDAR hillshade showing the Test from Romsey to Nursling. The river has created a wide valley within the geological formations of the Hampshire Basin, an easily eroded bedrock of gravel, sand and clay. A network of channels, many man-made or man-managed, cover the floodplain. Roads and field banks are visible on broad river terrace on the valley floor, with earlier terraces flanking the valley.
LiDAR hillshade of the Itchen valley south from Winchester. The river runs through Chalk bedrock with its distinctive topography of dry valleys.
The outline of Roman Winchester can be traced in the LiDAR at the top of the image. The town extended onto the floodplain of the Itchen.
LiDAR image with surface and tidal water showing the Test and Itchen rivers flowing south from the Chalk and through the Hampshire Basin. The river valleys widen as they reach the more easily eroded geology. Rain water falling on the Chalk reappears at springs along the edge of the Basin, creating a well-watered landscape - a striking contrast to the dry valleys of the chalk bedrock.