The Physical Environment

THE PHYSICAL ENVIRONMENT

Shropshire divides naturally into two halves whose contrasting physical characteristics (fn. 1) provide the controlling conditions for agriculture. The Severn, flowing south-east through the county from Melverley to Alveley, drains virtually all Shropshire (fn. 2) and almost everywhere (fn. 3) marks a convenient boundary between the two halves. South and west of the river is an upland country of Palaeozoic rocks, forming the greater part of the Welsh border hills and in the west including the eastern edge of the central Welsh plateau. It is a land of hills and ridges ('edges') separated by dales and drained by rivers and brooks for the most part of no great size; in the west it gives way to the plateau dissected by the river Clun. By contrast the eastern and northern regions of the county are part of the wide rolling plain formed by the foundering of the Palaeozoic floor in early Mesozoic time; it extends into mid Staffordshire and Cheshire and forms one of the principal lowland interruptions of highland Britain. The Shropshire portion of the plain, like the Staffordshire and Cheshire portions, is interrupted here and there by sandstone hills (fn. 4) which do not, however, alter the essentially gentle landscape characteristics which link it with the English midlands. In north-west Shropshire the plain runs up to the foothills of the Berwyn Mountains and an abrupt change to a Welsh upland landscape.

Rich in the great variety of its geology, Shropshire features most of the geological periods, and in more recent geological times glaciation has had profound effects. During the last major glaciation, from about 40,000 B.C., two great ice sheets, known as the Irish Sea Ice and the Welsh Ice, were active in the Shropshire area. By erosion, deposition of debris (gathered from as far as Scotland and the Lake District), and drainage diversions, important modifications of the landscape occurred. Though the upper soil coverage often closely reflects the underlying solid or drift geology, the effects of climate, relief, and vegetation sometimes produce different soils on similar rocks. Western Shropshire, mostly in the upland regions, has significantly higher rainfall than the eastern parts of the county (fn. 5) and the lighter, better drained soils are found mainly in the east too. In terms of soil types, agricultural use, and settlement pattern therefore the county cannot be divided into natural regions simply on the basis of relief. A consideration of geology, relief, soils, climate, and drainage, however, enables a more accurate picture of the Shropshire environment to emerge and reveals eight major regions with a number of sub-regions.

SOUTH SHROPSHIRE

South Shropshire seems capable of minute division into sub-regions: 'every ridge and dale... is highly individual in both its structure and relief, as are the Clee Hills to the east and the mass of Clun Forest to the south-west. Innumerable pays here form perfect examples of the French concept of small sub-regions.' (fn. 6) Despite the area's complexity, however, a broad division does seem possible, and the regions between the Worcestershire boundary and the Stretton Hills may be distinguished from those further west extending to the Welsh border.

The Clee Hills plateau

In the Devonian period the recent closure of the Iapetus Ocean left a continental mass with mountains over central and northern Britain, and to the south a retreating sea. Old Red Sandstone, the non-marine facies of the Devonian, forms a wide triangular plateau around the peaks of the Clee Hills. The Clees are the eastern outpost of the Welsh border hills towards the midland plains. Two table-topped masses rise from the broad Old Red Sandstone plateau. They are the Titterstone Clee (533 m.) and, to the north, the Brown Clee with its twin knolls of Clee Burf and Abdon Burf (545 m.), the highest land in Shropshire. Outcrops of Carboniferous Millstone Grit and Lower and Middle Coal Measures form the base of the Clee Hills, which are capped by thick layers of volcanic dolerite or basalt (the black 'Dhu Stone'). (fn. 7) At Titterstone Clee a narrow band of Carboniferous Limestone encompasses the northern and southern flank of the hill. The sandstone plateau tilts down to the south-east where, in the valley of the Borle brook, the Lower and Middle Coal Measures are encountered again at Highley and Kinlet on the northern edge of Wyre forest. (fn. 8)

The plateau supports a large area of leached brown soils, sometimes with gleying, which can cause waterlogging. There is little drift on the plateau, however, and the sandstone decomposes and weathers easily into marl producing silty loam over silty clay loam. The porosity of the underlying rock and the undulating landform provide some natural drainage, (fn. 9) and rich brown earths are found as high as 335 m. on the Brown Clee. (fn. 10) Early settlers favoured both the defensible summits of the Clee Hills (crowned with forts in the Iron Age) and the loams of the alluvial silts and clays in the valleys. (fn. 11) The plateau itself, however, was capable of cultivation, though more adapted to grass and cereals than to fruit or roots. The predominant soil types on the outcrop of Coal Measures to the east are acid-brown and surfacewater gley soils; those soils also occur on the slopes of Titterstone Clee where finetextured head containing occasional dolerite boulders occurs. The soil is poorly drained and of a sandy loam or loam or clay texture. The summits of the Clees show areas of well drained acid-brown soils and podzolized soils, but altitude, slope, and the thin, shallow, infertile soils, often wet or stony, produce only poor vegetation and rough moorland grazing, much of it still uninclosed in the 1980s. (fn. 12) The platforms surrounding the summits tend to support surface-water gley soils or peaty gley podzols. The Brown Clee is pocked with small spoil banks of coal shale and waterlogged man-made holes. The heavy leaching of the podzols and acid-brown soils restricts their agricultural use, though grass and cereals can be grown. In south Shropshire generally the cattle-corn economy flourished mainly in the valleys until the late 18th century but during the wars of 1793-1815 the need for more home-grown cereals caused a great extension of arable in the region (fn. 13) and gained for it the name 'Wheatland'; the name-used in Bridgnorth c. 1740 to distinguish lands west of the Severn from those on the east (the Ryeland)- indicated that wheat was the chief cereal that could be grown in the area. (fn. 14) The fall in corn prices after the 1870s caused most of the area's arable to be laid down to grass by c. 1900, primarily for the raising of store cattle. By the late 1930s a sparse though fairly even distribution of small arable fields did not detract from the region's character as a major stretch of improved grassland. (fn. 15) It is the flatter lands over the sandstone plateau that tend to be used for arable, while the steeper valley sides are fit only for rough grazing. Thin arms of richer brown warp and ground-water gley soils intrude into the plateau wherever riverine alluvial silts and clays have built up.

A significant sub-region is formed by the southern slopes of the plateau dropping down to the Teme valley. The area eventually became a small extension of the Herefordshire and Worcestershire cereal and fruit-growing region. The area's geology and soil are the same as those of the plateau to the north and the advance of mixed farming that was achieved by c. 1750, with good cereal acreages (including winter corn), the spread of hopyards, and the growth of new crops like clover and turnips, doubtless owed much to the southern aspect of the land. Orchards were spread over some 10-20 per cent of the farm land by the late 1930s. (fn. 16) Oast houses remained a common feature of the landscape in the early 1950s but only a very small acreage of hops was then grown. (fn. 17) The meadows and pastures of the Teme and the South Rea valleys also favoured some dairying.

Wenlock Edge and the dales

The region, encompassing all the land between the Clee Hills plateau in the east and the south Shropshire uplands and south-west Shropshire in the west, is one of very varied relief, an undulating landscape composed of the ridge of Aymestry Limestone bounding Corve Dale on the west and the parallel Wenlock Edge, with Corve Dale, Hope Dale, and Ape Dale intervening. A picturesque and well settled area, a regular belt of scarp and vale topography running SSW.-NNE. in line with the Church Stretton Fault, it is broken at its southern end by the plunging Ludlow anticline. Corve Dale runs down almost 20 km. south-west from its head near Bourton, in Much Wenlock, to Stanton Lacy; there it opens into a plain between Onibury and Ludlow, where the Onny and the Corve flow into the Teme. Westwards the intermontane plain and Corve Dale are bounded by the Upper Silurian Ludlow beds which form the limestone hills of Stokesay and Onibury parishes and the long escarpment of Wenlock Edge. (fn. 18) Much visited and well recorded by geologists, the area displays a folding of the limestone and shale beds forming curving infacing escarpments surrounding the lowland Wigmore Basin, just in Herefordshire; it contains classic Silurian outcrops whose fossils have led to significant discoveries in the geological and tectonic history of southern Britain. The succession of SSW.-NNE. scarps and dales is based on underlying Silurian rocks of varying hardness. All are beds of a shallow-water shelf facies formed under marine conditions, with the sea gradually retreating at the end of the period. Southern Britain then lay south of the equator but was drifting north. Some of the region's fossil beds have yielded important insights into the climatic and marine conditions then affecting Britain.

At the western escarpment (fn. 19) of the Clee Hills plateau the Old Red Sandstone is thrown down to form the floor of Corve Dale. The redness of the ploughed fields on the dale's eastern side derives from the non-marine Downtonian sandstones and marls before the Silurian Upper Ludlow siltstones and limestones emerge; those formations have been reclassified as Leintwardinian and Whitcliffian Beds, mainly through the identification of their fossils. There is a change from marine to non-marine facies at the top of the Upper Ludlow Shales or Whitcliffe Beds as witnessed by the appearance of gastropods and bivalves in the area. Immediately above the Upper Whitcliffe Beds lies the famous Ludlow Bone Bed, once viewed as the Devonian base but now placed at the end of the Silurian. The bed is made almost entirely of organic remains and contains the earliest sizeable grouping of British vertebrate fossils.

On the west Corve Dale is bounded by the escarpment of emerging Aymestry Limestone now known as the Bringewood Beds. Owing to faulting the scarp is frequently dissected by the valleys of streams. Beyond, to the west, lies Hope Dale, a valley or step feature based on the older, softer beds of Lower Ludlow Shales, now reclassified as Eltonian Beds. The Bringewood Beds contain thick shell banks in places but only solitary corals; Wenlock Edge, however, the succeeding parallel ridge of richly fossiliferous Much Wenlock Limestone, contains corals built up into a patch reef facies. The Wenlock Limestone has resisted erosion longer than the softer shales which (topographically and in geological time) lie either side of it. Wenlock Edge therefore stands proud of Hope Dale (Eltonian shales) and Ape Dale (Buildwas and Coalbrookdale shales), forming a straight ridge running 40 km. north-east from Craven Arms to Much Wenlock. It is unbroken for many kilometres, though in places dissected by valleys of streams draining (through the more frequent gaps in the Aymestry Limestone ridge) to the Corve. Both limestone scarps have been quarried and both are extensively wooded, though with bare grey crags on the summits.

The wooded scarp of Wenlock Edge is regarded as an outstandingly beautiful part of the county; nevertheless its heights, even though they rise to no more than c. 300 m., can be severe and inhospitable. On the upper slopes of Wenlock Edge and in Ape Dale and the Plaish brook (fn. 20) valley the typical soils, derived from silty shales and naturally poorly or imperfectly drained, are brown silt loams over silty clay loam. (fn. 21) In Corve Dale the valley floor is alluvial over the Old Red Sandstone (fn. 22) and there are silty loams and good heavy red soils. The central raised sandstone ridge offers drier sites for settlement, situated as it is above the damp river pastures. In the region as a whole there are few obvious signs of prehistoric lowland settlement, though there is evidence of prehistoric settlement on the alluvium around Bromfield and there was Roman settlement in Ape Dale and the Plaish brook valley and perhaps in Corve Dale too. Saxon settlement, possibly based on a residual Romano-British settlement pattern with Corfham (later a royal estate) as a nucleus, probably dates from the 7th or early 8th century (fn. 23) and most settlement in Corve Dale is on marl and gravel ridges. (fn. 24) Corve Dale is one of the more favoured parts of south Shropshire and in the mid 17th century, when there were large arable acreages, mixed farming was taking hold despite the persistence of open fields (albeit perhaps fragmented) on one large estate there. By the 1820s the Corve Dale farmers were prosperous by comparison with those on the Clee plateau. (fn. 25) Imperfect drainage gave rise to long-surviving areas of open waste, (fn. 26) but underdrainage, installed by one large Corve Dale landowner in the 1830s and 1840s, (fn. 27) enables good cereal crops to be grown and excellent grass, (fn. 28) and the area has rich fattening pastures and some very good arable land. (fn. 29)

Also of the Silurian era is the double horseshoe-shaped escarpment just west of Ludlow, caused by folding of the rocks during late Ludlovian times. The movement created uplift in the earth's surface in the area and is known as the Caledonian Orogeny. The corresponding syncline, or dip feature, is north-west of Ludlow.

The east Shropshire coalfield

The geology and relief of the coalfield and the Wrekin associate the region with south Shropshire rather than the north. The region's undulating plateaux, mostly over 122 m. and rising to 407 m. at the Wrekin summit, and its productive Coal Measures extend north from Shirlett across the Severn Gorge to Lilleshall and interpose a distinctive landscape between the plains of east and north Shropshire. On the east, near Kemberton and Priorslee, the Upper Coal Measures disappear beneath the Carboniferous (Permian) sandstones and marls that form the fringe of the eastern plain. On the north-west the Lower and Middle Coal Measures run up against the volcanic rocks of the Wrekin and its Cambrian and Silurian foothills; farther south they are faulted against the Silurian Upper Ludlow Shales. The western edge of the region, beyond the productive coalfield, is formed by the major Church Stretton Fault and the lesser Brockton Fault, and to the south-east lies another lesser fault, the Wrekin Fault. The Church Stretton Fault, like the Pontesford-Linley Fault farther west, was initiated during the Pre-Cambrian period, and all Shropshire's Pre-Cambrian outcrops occur along the line of, or between, those two great fault systems. The metamorphic Rushton Schists, southwest of the Wrekin, are only a small outcrop but could be the basement to a larger area of Shropshire; they are probably older than the Pre-Cambrian volcanics and Longmyndian sedimentary rocks found west of the coalfield. An even smaller area of Pre-Cambrian metamorphics at the south-western end of the Wrekin displays Primrose Hill Gneisses and Schists similar to the Malvernian Gneisses. Later in the Pre-Cambrian sequence comes the igneous complex of Uriconian Volcanics occurring in two belts across the county. The eastern belt runs SSW.-NNE. along the Church Stretton Fault line. The northernmost outcrop is at Lilleshall, and more volcanic rocks occur on the Wrekin and the Ercall and also near Wrockwardine along the Brockton Fault.

During the Cambrian period Shropshire contained the shoreline of a still widening Iapetus Ocean, and the rocks of that period are mainly a shallow-water marine sequence. Like the Pre-Cambrian rocks, the Cambrian rocks are closely associated with the major fault systems running through the coalfield. The Cambrian period in the region is represented by the Wrekin quartzite and a large area of Shineton Shales extending from a point south of the Severn to the southwest end of the Wrekin. There is also a small outcrop of Cambrian Lower Comley sandstone at Lilleshall. The northern end of the belt of marine Silurian rocks known as Wenlock Edge also runs into the coalfield, comprising shallow-water shelf sediments left by the retreating Iapetus Ocean.

The onset of the Carboniferous period brought a return to marine conditions followed by a gradual change to terrestrial sedimentation. It was during that phase that the coalfield's rich natural resources were laid down: coal, ironstone, refractory clays, and limestone.

The hummocky terrain of the plateaux either side of the Severn Gorge, particularly visible at Windmill Hill, represents drumlins formed of boulder clay during the glaciation of north Shropshire. Valleys such as Coalbrookdale were etched across the plateau on the fringe of the Irish Sea Ice. As the ice retreated to the plains of north Shropshire and Cheshire, Lake Lapworth was formed. Owing to the northerly drainage being blocked by ice the entire lake had to drain over the watershed between Benthall Edge and Lincoln Hill to a tributary of the river Stour. The meltwaters then gouged out the deep gorge that became the course of the Severn, whose upper catchment area had formerly drained north. The soft clays and sandstones through which the Severn Gorge is cut make its sides unstable, as testified by continuing landslips. Smaller tributary streams, cutting down slower than the Severn, created hanging valley effects above the Severn valley floor. The rapid streams in the side valleys provided industrial power from the 17th century.

The main drift cover is boulder clay. (fn. 30) Acid-brown and surface-water gley soils cover much of the area, usually resting on the Coal Measures. Drainage varies from good to poor and the soil is generally a sandy loam. A siltier loam mix characterizes the leached brown soils found mostly in the east. Smaller patches of well drained acid-brown and podzolized soils also occur, overlying Pre-Cambrian volcanic rocks. In the Middle Ages the district was heavily wooded, with a wood-pasture economy; even today large areas of wood remain. Increasing industrialization from the late 17th century transformed the landscape, especially in the central area around Dawley and Oakengates, with mining spoil, clay workings, and sprawling settlements, and over the next two centuries agriculture gradually became a relatively less important part of the region's economy. Away from the central parts of the coalfield, however, the region's landscape remained largely agricultural and rural. Even in the central area agriculture survived. In the 1930s there was a considerable amount of dairying, and some of the farming around Willey, Broseley, Madeley, and Stirchley was arable. In places there was rough grazing on levelled pit mounds or between surviving ones as, with the ebb of industrial prosperity after the 1840s, agriculture was reinstated in areas from which it had been displaced. In the 1960s and 1970s, as Dawley (later Telford) new town was built, agriculture virtually ceased in the central part of the coalfield region north of the Severn. (fn. 31)

The central uplands

The central uplands contain perhaps the most varied and spectacular scenery in Shropshire and some of Britain's oldest rocks. The region runs from the western watershed of Ape Dale and the Plaish Brook valley to the Welsh border west of the Shelve Plateau, and from Linley and Wistanstow in the south to Pontesbury in the north. Most of it lies over 183 m. and many parts over 300 m. The topography ranges from the line of whale-backed volcanic hills along the Church Stretton Fault through the fertile valleys either side of the Long Mynd to the bleak open plateau lands of the Long Mynd and the Shelve district and the jagged skyline of the Stiperstones ridge; its diversity reflects to a great degree the underlying rock beds.

Glacial deposits apart, the region's geological sequence is almost entirely early, starting with the Pre-Cambrian (4,600 million to 570 million years ago) and continuing through the succeeding Cambrian, Ordovician, and Silurian periods. All the Pre-Cambrian outcrops lie between, or along the line of, two great SSW.NNE. fault systems, the Church Stretton and the Pontesford-Linley faults, and the major part of both runs through the region. The fault systems played a fundamental role in the process of sedimentation in the region, as can be seen from the way that the geological strata follow the direction of the fault lines. The igneous suite of Uriconian volcanics is divided into two belts (the Eastern and Western Uriconians) along the line of the two faults. They form a line of hills and comprise a great variety of volcanic rock types, varying from basalt and rhyolite lavas to coarse- and fine-grained tuffs (ashes). The Eastern Uriconians appear as a line of hog-backed hills on the eastern flank of the Long Mynd: Ragleth, Hazler, Helmeth, Caer Caradoc, and the Lawley. The outcrop is found again north of the Severn, and east of Helmeth and Caer Caradoc it continues with the large mass of the Hope Bowdler, Willstone, and Cardington hills. The Western Uriconians start in the south at Linley and, after a 5-km. gap, continue with the ancient masses of Earl's Hill, Pontesford Hill (possessing important dolerite intrusions), and Plealey. Newer, but still Pre-Cambrian, are the Longmyndian sedimentary rocks. They are late Pre-Cambrian shallow-water sediments deposited in a subsiding shallow marine trough between the two fault systems, close to the shore line of the widening Iapetus Ocean when Shropshire lay just within the continental mass on its south eastern margin. The Longmyndian group is divided into the higher Wentnor Group of purple sandstones and conglomerates and the lower Stretton Group of sandstones, siltstones, and shales. The whole sequence forms c. 8,000 m. of sediments. The major outcrop is the massive smooth-topped Long Mynd plateau formed of slates and sandstone. It covers c. 50 sq. km. and rises to 517 m.; most of it remains uninclosed pasture. (fn. 32) Its uncompromising outline is interrupted by deeply cut narrow valleys, known locally as batches or hollows.

A complete Cambrian sequence, including Comley sandstones and limestones and also shales, outcrops east of the Lawley and around Hill End on the eastern side of the Cardington hills. On the western flank of the Long Mynd, however, the line of Cambrian beds following the Pontesford-Linley Fault forms a very different landscape of deep open valleys and long ridges. Thick boulder clay covers the higher spots, and Ice Age lake deposits are found lower down. The landscape is based on a long narrow outcrop of Shineton Shales deposited in a thin shallowwater marine environment.

A great belt of Ordovician strata runs SSW.-NNE. between Wenlock Edge and the Church Stretton Fault, extending from the Onny valley in the south and running north on the eastern side of the Stretton Hills and Caer Caradoc. The outcrop is called the Caradoc Sequence and is entirely a shallow-water deposit with abundant shelly fauna. Various limestones, sandstones, shales, flags, and grits are included in the group, some of them folded and faulted by movements along the Church Stretton Fault. The igneous type Ordovician rocks found farther west are practically non-existent but the Shelve Plateau contains the full Ordovician sequence, igneous and sedimentary: 4,500 m. of shallow-water sandstones, deeperwater shales and siltstones, some limestones, and beds of volcanic ashes and lavas. There are also pockets of intrusive and extrusive andesites, basalts, and dolerites, notably the great rounded dolerite cone of Corndon Hill (Mont.), rising to 513 m. All the underlying geology gives rise to wild bleak upland scenery punctuated by rugged peaks formed of the harder beds. Most pronounced of the SW.-NE. ridges, the Stiperstones are formed of tilted Arenig quartzite eroded into the sort of jagged hill-top crowns seen on Dartmoor. The Stiperstones slopes are strewn with great quartzite boulders resulting from Ice Age action. The local volcanoes responsible for the (relatively thin) Ordovician igneous beds were situated in or near the Shelve area. The Shelve Plateau lies at c. 365 m., with the Stiperstones rising 150 m. higher. It is an inhospitable land supporting only rough uninclosed pasture. (fn. 33) Lead was formerly mined from Late Ordovician mineralization.

The last geological era represented in the region (apart from the recent Pleistocene) is the Silurian, whose strata appear west of the Church Stretton Fault as a thick basin facies like those of the Long Mountain on the region's western edge; the Long Mountain is composed of soft sedimentary Upper Silurian strata folded into a syncline. Most of the area is formed of marine Silurian, though there is a small pocket of Downtonian near Vennington. The Long Mountain attains 408 m., and the effect of folding is to give it a softer relief than the Shelve and Long Mynd plateaux to the east. Boulder clay from Ice Age frost action overlies the sedimentary beds.

Over the region's highest areas, such as the Shelve Plateau, and over the steep valleys and scarp of the Long Mynd and the belt of volcanic hills by the Church Stretton Fault, the soils are largely acid-brown and podzolized. They overlie the Pre-Cambrian volcanics, sandstones, and siltstones, and the Ordovician beds. The extensive acid-brown soils tend to be well drained and a silt loam or loamy sand. Leaching on such soils, with loss of important nutrients, can be severe and is worst on the infertile, highly podzolized soils of exposed areas like the Stiperstones or the bleaker ridges of the western Shelve area. Many such areas support only heath, open moorland, or rough pasture. On the Long Mountain surface layers have been disturbed by landslips and solifluxion, producing scree and some large blocks of rock. The well drained, stony, acid-brown soils are head, derived by colluvial processes from the Silurian strata beneath. The acid-brown soils in the western Shelve area tend to be siltier and deeper, except for the steeper slopes where the soil is thinner.

Surface-water gley soils and leached brown soils with gleying predominate on the region's lower land and at the feet of the ridges. They mostly rest on Ordovician or Silurian beds, themselves sometimes overlain by glacial boulder clay. Natural drainage on such soils is often poor and their use may depend on artificial drainage. Most soils of the type, however, can grow good wheat; they vary from a silt loam to a sandy clay loam or a sandy loam. Impermeable boulder clay often fills valleys west of the Stiperstones, as it does in the upper reaches of the West Onny. Where layers of glacial sands or gravels occur, as in the northern section of the Long Mynd, the soil type is a sandy acid-brown soil of a sandy loam quality. The river courses usually support ground-water gley soils or brown warp soils (formed from the recent build-up of alluvial silts), clays, and possibly some glacial drift deposits. Drainage varies.

Much of the region is bleak wild upland interspersed with heath and moorland, but there are fertile valleys, such as Stretton Dale and the upper Rea valley, and land successfully supporting mixed farming. Mainly, however, it is stock rearing country (fn. 34) with an emphasis on sheep. The region's villages, as in most upland areas, are usually small and widely scattered, and the region has never been highly populated.

South-west Shropshire

South-west Shropshire is a remote upland region of grass pasture and moorland. Much of it was part of Wales in the Middle Ages and many of the place names are Welsh. Morphologically the region is an extension of the Welsh Plateau and a continuation of the Kerry Hills (Mont.). The Clun and Teme river systems have deeply dissected the plateau, forming a series of broad-backed ridges divided by steep narrow valleys. The Teme and the Clun drain the region in the south and centre, the Onny and the Camlad in the north. Slopes vary from moderate to steep, and the higher summits join up with the old plateau surface. The highest point, Beacon Hill (Radnors.), rises to 547 m. The landscape becomes softer in the east, breaking into a series of isolated rounded hills.

The region is based entirely on Silurian beds, namely the marine Silurian and sizeable outcrops of Downtonian. The Silurian rocks represent sedimentation left as the Iapetus Ocean finally retreated west in southern Britain. The thick basin facies Silurian deposits are the same as those of the Long Mountain farther north. The beds in the basin are all of the Ludlow and Downton series in age and are mostly graptolitic. A deep layer of siltstones and mudstones, c. 2,000 m. thick, makes up the Ludlow series and a thinner layer of mudstones, shales, and siltstones, c. 600 m. deep, the Downton series. The latter are situated around Clun and in a large block on the region's western border. Both series contain fossil-rich silty beds, the basic beds of the Downton Castle sandstone. Some time after the Downton beds were deposited Caledonian folding affected the area.

Most of the region supports well drained acid-brown soils of a silt loam texture. The underlying Silurian rocks are all either non-calcareous or only slightly calcareous. The surface layers of the beds have been disturbed by landslips or solifluxion, as is shown by the build-up of scree-like material or head. Consequently the overlying soils are largely developed from colluvium and head; colluvial soils predominate on the steep slopes, head on the lower slopes. Boulder clay occurs infrequently but is more likely to be found in the east, particularly around river terraces and alluvial deposits. Acid-brown soils in the upland areas are most suited to grass for sheep grazing and in their natural state usually support bracken and dry heath grassland. Leaching of such soils is intense, but not as intense as with the podzolized acid-brown soils found on the gentler hill slopes of summits over 365 m. Those imperfectly or well drained soils often support heather and bilberry. Where there are patches of boulder clay or head, peaty gleyed podzols may occur. The presence of fairly impermeable boulder clay beneath subsoils often produces a waterlogged peaty surface layer. Such areas generally remain semi-natural moorland. On other slopes of hills above the 365-m. contour, pockets of surfacewater peaty gley soils occur. They are usually very poorly or imperfectly drained, and of a silty clay loam texture. Again such areas are more particularly suited to sheep grazing because the combination of high acidity, high rainfall, and poor drainage makes successful agriculture very difficult. The semi-natural vegetation may be heather and bilberry, and in the wetter areas moor grass, rushes, and cotton grass. Groups of rushes mark the presence of flushes where springs keep the soils wet. Long thin arms of brown warp soils and ground-water gley soils intrude into the uplands and mark the courses of the Clun and Teme. This silty clay loam mix is based on alluvial silts and clays.

The upland soils, brown, naturally free-draining silt loams, mostly between 245 m. and 365 m., are generally suitable for cultivation and there is much evidence of prehistoric settlement. (fn. 35) In medieval times the valleys of the Teme and its tributaries gave access to a remote upland section of the middle march (fn. 36) where Clun and Bishop's Castle became the main settlements. Population and settlement figures have never been high and the commonest form of settlement remains the isolated farmstead. Much of the area is heath or moorland. Trees and hedges are oftener found in the valleys than on the windy uplands, though from 1924 the western part of the area was extensively planted by the Forestry Commission, and by 1939 c. 1,200 ha. were growing conifers. (fn. 37) In the 1930s there was a higher proportion of arable in the region, mostly in the eastern part, than elsewhere in south Shropshire, (fn. 38) and there was a certain amount of dairying. Sheep farming, however, remains the area's most characteristic enterprise.

NORTH SHROPSHIRE

Compared with south Shropshire the regions largely east and north of the Severn appear much more uniform in terms of geology and relief and there is little land over 122 m. Yet there too sub-regions can be identified, perhaps more easily indeed than in the more complex south.

The eastern sandstone plain

Geologically and scenically the eastern sandstone plain belongs to the west midlands. The rich red sandstone countryside, most of it below 122 m., combines wide tracts of flat land, cut by deeply bedded streams, with gently rolling hills and patches of hummocky glacial terrain. The underlying Carboniferous, Permian, and Triassic deposits are the same as those in the west midlands. In 1086 much of the region was in Staffordshire, and in terms of geology and soil coverage it has little in common with Shropshire's upland regions to the west. The annual rainfall is lower than in western Shropshire, annual hours of sunshine are greater, and average temperatures are somewhat higher.

Upper Coal Measures fringe the plain to the west and south. Near Bridgnorth lies the northern end of the Wyre Forest coalfield, positioned over the Symon Fault where the lower layers have eroded. Most of the plain is floored by Bunter deposits of the intermediary Permo-Trias age. The Bunter sandstone, a useful reservoir of underground water, (fn. 39) is found extensively in the region; now known as the Bridgnorth or Lower Mottled sandstone, it is part of the Permo-Triassic New Red Sandstone, which underlies large areas of east and north Shropshire but in both regions is thickly overlain by glacial clay or sand and gravel. The Bunter Pebble Beds, now known as the Kidderminster formation, represent the base of the succeeding Triassic period in east Shropshire. They contain many quartz and quartzite pebbles and were probably laid down in a delta environment at the end of the Permian age 280-225 million years ago. The period was marked by subaerial erosion of the local highlands and deposition in the developing graben system. The breccia formation of that time, such as the Clent breccia exposed 4 km. south of Claverley, consists of angular calcareous scree material plucked from the limestone uplands and deposited in a mix of red marl in a red sandstone matrix. Evidence for the continuation of such airborne deposition, with some intermontane lake deposition, is provided by the Bridgnorth sandstone already referred to.

After the formation of the intermediary Permo-Trias Bunter sandstone and pebble beds the Triassic period proper (225-190 million years ago) began, when the stretch of Keuper sandstones and marls, found in the extreme east of the plain, was deposited. The Keuper sandstone (now known as the Wilmslow Sandstone) and the succeeding Keuper marls (now known as the Mercia Mudstone group) were both formed in largely non-marine, semi-arid conditions. The terrestrial landscape was subject to narrow horst and graben structures, which directed sedimentation, including intensive fluvial deposition, in east Shropshire. The finertextured Wilmslow Sandstone of east and north Shropshire probably signifies a slowing down of some of the river systems, caused by the erosion of the nearby uplands. After a short-lived marine incursion, the former terrestrial environment was restored and the saliferous marls of the Mercia Mudstone group were then deposited. These impermeable red-brown marls, layered with other rocks like sandstone, quartz, and shales, were formed by deposition in shallow water.

East Shropshire, like the northern plain, bears distinctive reminders of Pleistocene glacial activity. Near the eastern county boundary, by Weston under Lizard (Staffs.), the low swell of boulder-clay end moraines represents the halt of the Irish Sea Ice in its northerly retreat. Other glacial mounds of sand and gravel are particularly prominent near Blymhill (Staffs.) and Boscobel and along the valley of the Back brook near Newport. The mounds may be worn down eskers or kames deposited at right angles to the ice sheet. Of course the main impact of glacial action in the region is the general blanket of glacial deposits which often obscures all earlier geological formations.

Because there is so much underlying sandstone and overlying sands and gravels, a very large proportion of the region exhibits light, sandy, acid-brown and podzolized soils with poor water retention properties; there is almost no surface water and there are few shallow wells. Properly managed, the soils are well suited to market gardening and intensive agriculture, though the danger of drought makes them less suited to permanent pasture. Particularly sandy and more sterile soils usually occur over the mounds of glacial sands and gravels, and coniferous trees are often the only vegetation they support. Such poor podzolized soils once supported great stretches of natural heath, some of which has been reclaimed for conifer plantations. The old areas of scrub-heath, themselves the product of still earlier woodland clearance, usually denoted underlying beds of Bunter pebbles. Over the Keuper (Wilmslow) Sandstone the soil is noticeably moister and richer than it is over the Bunter pebbles and sandstones. The belt of Keuper marls at the eastern edge of the region displays an opposite extreme in soil coverage. There, as with the areas thickly covered by glacial boulder clay, the drainage is poor or imperfect, and the often impermeable nature of the deposit creates frequent surface streams. The soil is generally a sandy clay loam or a loam over clay loam or clay. In the extreme southern and western parts of the region, over the Coal Measures, siltier leached brown soils predominate, with a more variable free or imperfect drainage. Finally the flood plain of the Severn, particularly near Bridgnorth, has a build-up of alluvial silts and clays, and imperfectly drained gley soils are common there.

Originally almost the whole region was occupied by a great extent of woodland stretching from Staffordshire to Worcestershire. The creation of the royal forest of Morfe in Norman times inhibited the spread of settlement but there had been earlier settlement, often in the valleys or in the form of isolated farmsteads and hamlets. The shrunken villages and small moated medieval farms found to the south speak of restricted settlement and small-scale land reclamation in a marginal forest or heathland environment. Nevertheless there are also a few notably large and prosperous villages, such as Alveley, Claverley, and Worfield, of a type not found in the more extreme marginal environment of the meres and mosses of the northern plain. By the 18th century Morfe forest had lost its woodland character and was more or less scrub-heath. At inclosure (1812) the cleared land that had remained common waste was formed into regular fields. In many parts, however, the eastern plain still displays remnants of a more ancient landscape, marked by smaller irregular fields and high-banked winding lanes. By the early 18th century the region was known as the Ryeland from the suitability of its fine, dry sandy soils for rye and barley, (fn. 40) and in recent centuries the region has been more distinctly arable than any other part of Shropshire. (fn. 41)

The northern plain

In terms of relief the northern plain forms a very distinct region of Shropshire. It lies between 80 m. and 110 m., an extensive level region interrupted here and there by low red sandstone hills forming a gently undulating lowland landscape. The effects of glaciation, the soils, and the present landscape, however, are varied. The plain encompasses both arable and pastoral areas, as well as extremes of wild fenland vegetation and heathlands. The Severn, moreover, winds its way across the southern part of the plain, cutting into the eastern coalfield through the Severn Gorge, a legacy of glaciation. The fertile deposits of the Severn flood plain make a distinctive southern sub-region of the plain, both in terms of soils and of the resulting settlement and agriculture.

Much of the plain is based on Triassic or Permo-Triassic rocks, mostly sandstone and marls, but they are in turn heavily overlain by glacial drift and more recent deposits. The extensive area of Bunter (now called Bridgnorth) Sandstone was deposited in terrestrial conditions on a semi-arid continent 280-225 million years ago. It results from the sub-aerial, or wind-blown, erosion of the Varsican uplands and is typically red and lacking in fossils. Next in geological sequence are the Triassic Keuper sandstones and marls laid down under similar terrestrial conditions interrupted by marine incursions. Those deposits, occurring extensively in the central and northern parts of the plain, comprise a series of cross-stratified orangered sandstones, such as the Sherwood sandstone and the Wilmslow sandstone (originally called Keuper sandstone) and silts and mudstones like the Mercia Mudstone (originally known as the Keuper marl). Less extensive outcrops in the area are the Upper Coal Measures to the far south, around Shrewsbury, and the far east and west, and a patch of more recent Jurassic Lower and Middle Lias clays and silts south-east of Whitchurch. Lastly a spur of the much earlier PreCambrian Longmyndian sedimentary rocks intrudes into the plain, outcropping at Longden, Lyth Hill, Bayston Hill, and Sharpstone Hill and dividing the Cound and Rea drainage systems; north of the Severn it outcrops again east of Shrewsbury as Haughmond Hill.

Most of north Shropshire is covered by glacial drift and fluvio-glacial deposits, a legacy of the Welsh and the Irish Sea ice sheets. The Irish Sea Ice left the bulk of the drift and it is usually reddish brown in colour and composed of boulder clay intermixed with sands and gravels and rocks from the Lake District and southwest Scotland. The plain also shows the physical marks of glaciation more clearly than other parts of Shropshire: its varied topography of glacial or morainic hills, smaller drumlins, and boggy meres and mosses was created by late Pleistocene glaciation.

Discontinuous ranges of morainic hills running from Ellesmere and Cockshutt towards Whitchurch, evident for example at Breaden Heath, represent accumulated debris left by the retreating ice. Hills on the crest of the moraine can be quite steep sided, in contrast to the gentler slopes of the drumlins, as shaped and elongated by the slow-moving ice. The low drumlins provide useful islands of drier land in a generally damp area, and some farms are sited eligibly on them. Where hollows occurred in this glacial drift (possibly the result of pockets of slower melting ice) small meres have developed, as around Ellesmere, and some of them have developed into wet peaty hollows. Such shallow hollows contain the mosslands of the plain. Thick beds of fen peat began to accumulate as the hollows silted up; tests on Whixall Moss indicate that the process began soon after 8000 B.C. In the early modern period those inhospitable marginal lands accommodated a number of squatter settlements. Despite some 19th-century reclamation, the wetter mosses like Whixall Moss have retained their wild fenland character (fn. 42) and are still used for peat cutting.

Drift largely determines the nature of the region's soils. The boulder clay areas are capped by surface-water gley soils and leached brown soils with some gleying. They tend to be heavy textured loamy soils with imperfect or poor drainage, suitable for extensive cultivation only if effectively drained. Traditionally such soils, which cover large parts of north Shropshire, have been used for pasture, though with careful management wheat can be grown. The northernmost arc of land in the county, extending from Market Drayton by Grinshill to Oswestry and centring on Whitchurch, was increasingly notable from the 17th century as a dairying district with pig feeding as an important subsidiary enterprise until c. 1940. (fn. 43) Where the boulder clay is more intermixed with sands and gravels, as it is around Ellesmere, Cockshutt, and Welshampton, the soil tends to be somewhat loamier, more organic in the upper layers, and so more fertile; that has allowed successful arable cultivation.

Where the drift is mostly sands and gravels, lighter textured acid-brown soils or podzolized soils occur. They are sandy loams, usually greyish brown in colour and well drained. They are widespread over the plain, but the two largest areas lie in its north-eastern and north-western parts: one between Market Drayton and Ercall Magna with extensions north through Prees to Whitchurch and south to the lower Tern valley around Upton Magna, the other between Oswestry and the Severn (at Montford). The light sandy soils found on sandstone hills such as Nesscliff, Pim Hill, Grinshill, and Hawkstone attracted prehistoric settlement. Iron Age earthworks like Oliver's Point and Bury Walls cap the hills or (as at the Berth) lie in the low ground between them. Organic deficiency means that such soils are not inherently fertile, but they respond to treatment and are well suited to roots or oats. The north-eastern area was fitted for arable in the early modern period as sheep and cattle fattening developed, and the extensive remaining heaths (fn. 44) of the north-east and north-west were inclosed at the end of the 18th century when wartime cereal prices brought them into cultivation. The north-east, long retaining its identity as an area of improved heathland, contains smaller areas of podzols, gley podzols, and leached brown soils. The podzols tend to be sandy soils sitting on the glacial sands and gravels, and the leached brown soils, mainly along the northern edge of the improved heathlands, form a richer silty loam based on the Keuper marls and sandstones and the Coal Measures. There, in the 1920s and 1930s, dairying spread from the northern part of the plain. (fn. 45)

Areas of pure peat and peaty soils with poor or blocked drainage are found in the glacial morainic country to the north-west and in the east, notably in the Weald Moors. Their agricultural and settlement potential is severely limited without the aid of artificial drainage. From the late 16th century, when landowners were beginning to inclose and improve thousands of acres there, the Weald Moors were specializing as a livestock-fattening area. (fn. 46) In the later 18th century some of the ill drained peaty areas of the north-west, such as the Baggy Moor, were drained and cultivated.

Valleys like those of the Severn, the Tern, and the Rea give rise to rich alluvial silts and clays which form brown warp and ground-water gley soils of variable drainage. The light loamy soils of the Severn flood plain have attracted some of the earliest and most intense agricultural activity in Shropshire. Settlement has been severely limited on the flood plain itself, but in the river valley abundant crop marks signify both settlement and agricultural activity as far back as the Bronze Age. The flood plain of the Vyrnwy also yields evidence of prehistoric settlement. The southern part of the plain, south-east and south of Shrewsbury, includes the lowland valleys of the Bullhill and Cound brooks; south-west and west of Shrewsbury it includes the lowland parts of Pontesbury and Westbury parishes (the lower Rea valley) and the parishes to the north bordering the river. Those two southern extensions of the plain (fn. 47) were early occupied by relatively prosperous settlements with large open fields in Alberbury, Cardeston, and Ford on the free-draining soils of the breccia outcrop between Loton and Cardeston, an area where arable cultivation (with an emphasis on barley) remained notable even in the 1930s. (fn. 48) East of the county town as far as the lower Tern valley and including the Cound brook valley south of the Severn, light free-draining soils occur more frequently, and on the lower land correspondingly large arable fields are found from an early date; (fn. 49) the range of that area's arable enterprises was increased by the cultivation of sugar beet after 1927. (fn. 50) Mixed farming was widespread over the southern fringe of the plain in modern times, though here and there local conditions produced a different emphasis. (fn. 51)

Settlers in the north Shropshire plain have conspicuously taken advantage of the islands of higher and drier ground. Between the scattered nucleated villages lie isolated farms and hamlets, and man's recent efforts in the way of inclosure, drainage, and land reclamation have made an impact on the landscape. That is particularly noticeable in the formerly ill drained and inhospitable fenlands east of Ellesmere. Eighteenth-century inclosure left a rash of small squatter settlements which were often eradicated by the reclamation of large areas for cultivation in the next century. The whole area remains largely rural in character, thinly populated, and with remnants of a more ancient landscape in the wild fens and heathlands.

The north-west uplands

More than any other part of Shropshire the north-west uplands west of Oswestry bear a distinctly Welsh character with a hilly terrain, scattered pastoral farms, and small stone cottages. Tectonically the region is part of the Welsh system and on the far western edge of the region the underlying Ordovician sedimentary and igneous rocks represent the easternmost fringe of the Berwyn Mountains. A thick sequence of those earlier Ordivician rocks passes under the Carboniferous Limestone, and farther east the region is dominated by stretches of Carboniferous Millstone Grit (basically grits, sandstones, and shales) and the Lower and Middle Coal Measures. Those deposits were laid down under returning marine conditions followed by a slow change to terrestrial sedimentation when deltaic and swamp material built up, eventually forming the sandstone and Coal Measures found today. Marine layers with distinctive fossil fauna can be found extensively through the Coal Measures.

The region represents an eastern extension of the Welsh Plateau, which ends in steep scarp slopes just north of the region, beyond the county boundary. The land rises from 80 m. in the east to over 300 m. in the west at the Welsh border. Intensive glaciation over the last few million years affected the whole of north and central Shropshire and in the north-west uplands a reddish brown drift of boulder clay, gravels, and silts left by the Irish Sea Ice covers the solid geology. Particularly thick glacial deposits lie on the broad valley bottoms, on ledges on the valley slopes, and on the flatter hilltops. Glaciation also resulted in common rocky outcrops on valley sides.

The resulting topography is an irregular hilly terrain with deeply incised, broadbottomed valleys. The region has a higher than average rainfall for the county, 30-40 in. a year being recorded, with the highest figure reached in the west. Because of the porous nature of the rocks surface drainage takes the form of deeply engraved water courses such as the Morlas brook, the river Morda, and the river Tanat and its tributaries.

The soils based on the Carboniferous Sandstones are largely acid-brown. They tend to be shallow and strong but relatively well drained on the ridges and steepest slopes. The good drainage enables them to produce a good grass crop, generally used for rearing stock. On the more exposed summits infertile leached podzols support only poor rough grazing. The well drained leached brown and calcareous soils found in the Carboniferous Limestone areas tend to be shallow, subject to summer drought, and of limited agricultural value. Finally surface-water gley soils and leached brown soils with some gleying are also found in patches (over boulder clay deposits) throughout the region. They are poorly drained and often waterlogged in autumn or winter, though potentially good agricultural land if properly drained.

Because of the relief and the often infertile nature of the soils, the area has not seen intense agricultural activity and has been characterized by mixed woodland and rough grazing. The settlement pattern of isolated farmsteads and small hamlets has also been affected by the limitations of the physical environment, though in the warmer periods of prehistory there may have been more extensive use of the upland areas.