PHYSICAL STRUCTURE AND RELIEF

Highland Britain

Britain has a great diversity of physical characteristics and, despite its small area, contains rocks of nearly all the main geological periods. There is a contrast between the generally high relief of western and northern Britain and the lowland areas of the south and east. In general, the oldest rocks appear in the highland regions and the youngest in the lowland regions.

England

Though England cannot be considered as a very hilly country still it is far from being flat everywhere. The most important range of mountains is the Pennine range, regarded as 'the backbone of England'. It stretches from the Tyne valley in the north to the Trent valley in the south — a distance of about 250 km. The whole range forms a large table-land the highest point of which is Cross Fell (983 in), in east Cumbria above the Eden valley. Being an upland region the Pennines form a watershed separating the westward-flowing from the eastward-flowing rivers of Northern England. They also form a barrier between industrial areas (Lancashire and Yorkshire) on their opposite sides. Both sets of rivers have cut valleys into the uplands, two of which have created important gaps — the Tyne Gap and the Aire Gap. They have road and rail routes, which follow the rivers and link West Yorkshire with Lancashire and Cumbria. Some rivers flowing from the central Pennines have cut long open valleys, known as dales, which attract tourists because of their picturesque scenery. Rainfall in the Pennines is abundant, and their swiftly flowing streams used to provide power for woollen mills. Today the area is used for water storage: reservoirs in the uplands supply water to the industrial towns on each side of the Pennines.

Across the north end of the Pennine Range there are the grassy Cheviot Hills. The highest point is the Cheviot (816 m), near the Scottish border. The Cheviot Hills serve as a natural borderland between England and Scotland.

In north-west England, separated from the Pennines by the valley of the river Eden lie the Cumbrian mountains. These mountains form a ring round the peak of Helvellyn (950 m). Other peaks are Scafell (978 m) and Skiddaw (931 m).

The valleys which separate the various mountains from each other contain some beautiful lakes (Windermere, Grasmere, Coniston Water, Ennerdale Water, Thirlmere, Ullswater, Hawswater). This is the celebrated Lake District, where many tourists resort every year, and where the famous poets Wordsworth, Coleridge, Southey, Quincey lived and wrote.

Thirlmere and Hawswater are in use as reservoirs for the Manchester area, and permission has been granted for Manchester to take water from Ullswater and Windermere. Crummock Water supplies Workington and other towns of West Cumberland.

The region is sparsely populated and sheep rearing is the main occupation of the farmers. A typical lakeland farmhouse is built of stone, quarried locally, and roofed with slate, also obtained in the region. Around it are a number of small fields, separated from one another by dry stone walls.

The Lake District is exposed to the westerly winds and rainfall is exceptionally high. The village of Seathwaite, with an annual average rainfall of 3,300 mm, claims to be the wettest inhabited place in the British Isles.

The South-West Peninsula of Great Britain includes the counties of Cornwall, Devon and Somerset. The region is made up of a number of upland masses separated by lowlands, which, apart from the Plain of Somerset, are of limited extent. The uplands of the South-West Peninsula are not ranges of mountains or hills, but areas of high moorland, the most extensive being Dartmoor and Exmoor. On the north side of Dartmoor the land rises to over 600 m (Yes Tor — 619 m, High Willhays — 621 m). These are the highest summits in England south of the Pennines. Much of the area has been eroded, resulting in a series of platforms between 150 and 300 metres.

The South-West region is essentially an agricultural area. The areas of best soil occur around the southern borders of Dartmoor, in northern Devon and in the Vale of Taunton. On the lower land between the moors, both in Cornwall and Devon, are fertile river valleys.

The westernmost point of the English mainland is Land's End, a mass of granite cliffs which plunge with dramatic steepness into the sea. The most southerly point of Great Britain is Lizard Point, a mass of serpentine, greenish metamorphic rock, which people living in the neighbourhood carve and polish into attractive ornaments.

The South-West Peninsula presents numerous attractions for the holidaymakers and the artists, and tourism is one of the most important activities of the region.

Wales

Wales is the largest of the peninsulas on the western side of Britain. It consists of a complex of worn down mountain ranges, representing high plateaux. They are called the Cambrian Mountains. The highest and most glaciated area occurs in the north, especially around Snowdon (1,085 m), and often the mountains approach close to the sea.

The Cambrians largely comprise the upland areas, generally and collectively described as the Welsh Massif. In the south the massif includes an important coal-field, on which an industrial area has grown. It is the most densely populated part of Wales, with some two-thirds of the total population of 2.8 million inhabiting about one-eighth of the area. Two relief divisions may be distinguished in South Wales: a coastal plain which in the south-eastern part around Cardiff becomes up to 16 km wide, and the upland areas of the coalfield proper, which rise between 245 and 380 metres. In recent years the region has experienced very acute problems with the decline in the coal industry and high unemployment rates.

Much of the remainder of Wales consists of bare rock, barren moorland and rough pasture, with only a few people to the square kilometre. But this region constitutes the heartland of Wales, for centered upon the massif is the Welsh culture where the traditions and language of a Celtic people are best preserved.

In the upland areas sheep are the basis of the rural economy, and in the low-lying parts near the coast and in the valley bottoms dairy farming predominates.

Scotland

Scotland may be divided into three major physical regions: the Highlands, the Southern Uplands and the Central Lowlands.

The Scottish Highlands lie west of a line from Aberdeen to the mouth of the Clyde. They form the most extensive and the most sparsely populated of the three regions. The mountains are separated into two parts by Glen More, or the Great Glen, a long crack in the earth's crust, running from north-east to south-west. To the south are the Grampians, which are generally higher than the North-west Highlands, and contain the loftiest summits, including Ben Nevis (1,347 m)-, the highest peak in the British Isles, and Ben Macdhui (1,309 m). They have also been more deeply cut by the action of glaciers and rivers. Glen More contains three lakes: Loch Ness, Loch Oich and Loch Lochy, and the first is said to be the home of a 'monster'. In the early nineteenth century the lochs were joined to form the Caledonian Canal which was equipped with 29 lochs and was almost 100 km in total length. Along the west coast the Highlands rise quite abruptly from sea level, so that westward-flowing rivers are short and swift. Rivers which flow generally east, such as the Tay and the Dee, have a relatively long course.

Climatically the region has some of the most severe weather experienced in Britain. The highly dissected nature of the landscape means that there are considerable local variations in climate over quite small distances and these variations are important.

The Highlands comprise forty-seven per cent of the land area of Scotland. At the same time, they house less than fifteen per cent of the Scottish population. The population is largely concentrated on the periphery of the massif, and nowhere else in Britain are the problems of depopulation and economic decline seen so clearly.

The economy of the region has traditionally been that of crofting, subsistent farming, in which the farmer (crofter) and his family consume all the produce. The crofter grows crops on a patch of land near his cottage, the main crops being potatoes, oats and hay. His sheep graze on the nearby hill slopes, and he may have one or two cows, to keep the family supplied with milk, and some poultry.

The Southern Uplands extend from the Central Valley of Scotland in the north to the Pennine Hills and Lake District in the South. Although for the most part an upland area, the boundaries of the region are not clear-cut in physical terms. The Cheviot Hills, composed largely of volcanic rocks, mark the central part of the boundary between England and Scotland. Upland areas extend into the Central Valley, just as the Cheviots merge into the Pennines and the lowlands on both east and west coasts merge into the lowlands of Northumbria and those that surround the dome of the Lake District.

These uplands form a plateau, which glaciation has eroded into smooth, rounded hills. The general level of this plateau-like surface descends from the higher northern margins in a series of steps.

The present-day economy of the region is dominated by agriculture. The region is clearly divided between the sheep pastures of the uplands and the more diversified farming areas of the lowlands. Sheep have been grazed on the uplands for the past six centuries and hardy local breeds, such as Cheviot and Black-face, have been developed which can withstand the snows of winter and produce excellent mutton as well as wool.

Throughout the Uplands population distribution is sparse and limited to isolated farmsteads and occasional villages and towns usually clustered in the valleys on the periphery of the uplands, particularly in Galloway, the name is given to the dales and lowlands of the south-west, and in the Tweed Basin.

The Central Lowlands of Scotland, sometimes known as the Midland Valley, lie between the Highlands and the Southern Uplands. For the most part this region is a lower-lying north-east to south-west trending area some eighty kilometres or so wide.

The Central Lowlands are by far the most densely populated of the three main regions of Scotland: they occupy about 15 per cent of its area, but contain about 80 per cent of its people.

Many of the people who left the Highlands during the eighteenth and nineteenth centuries settled in the Central Lowlands, particularly in the Glasgow region where industrial development was taking place at a rapid rate. The area was one of the major industrial centres of Britain, with important coal, steel, ship-building and engineering industries. The twentieth century has seen increasing problems in these industries and there has been a movement of population from the area.

In the fertile sandy soils in the south-west the farmers grow early potatoes. They also cultivate oats and in the sheltered Clyde Valley many are engaged in fruit growing and market gardening. Throughout the region sheep are reared on the hills.

Ireland

Ireland is predominantly a rural island, with a generally low density of population and indeed few large towns other than those situated on the coast. The regional geography of the island is simpler than that of Great Britain, and especially than the regional geography of England.

The Central Plain of Ireland stretches west-east across the country from coast to coast. Glacial action has created hollows, enlarged by solution of the underlying limestone by rain water, and many shallow lakes have been formed. A large proportion of Ireland's terrain consists of either bleak and uninhabitable mountain masses, or valleys and lowlands containing large loughs, innumerable smaller sheets of water, and great peat bogs that are useless except as a source of fuel. Lough Derg, on the River Shannon, is narrow, irregular, and nearly forty kilometres in length.

Around the plain is a broken rim of mountains. In the extreme north-east is the Antrim Plateau or Mountains of Antrim, which rise above 400 m and are composed of basalt. Off the north coast is the famous Giant's Causeway, where the basalt solidified in remarkable hexagonal columns. In the north and northwest are the Sperrin Mountains and the Ox Mountains, which with several other uplands reach more than 500 m in height. The loftiest mountains of Ireland are in the south-west — the Macgillycuddy Reeks, which contain Carrantouohill (1,041 m), the highest peak on the island. In the south-east the Wicklow Mountains rise to 926 m in Lugnaquillia. They form one of the most extensive masses of granite in the British Isles. And in the north-east there are the Mourne Mountains which rise steeply from Carlingford Lough to reach a height of 852 m in Slieve Donard.

Being geographically an island and a single unit, Ireland is politically divided into the Irish Free State and Northern Ireland, or Ulster, comprising today six counties: Antrim, Londonderry, Tyrone, Fermanagh, Armagh and Down.

Lowland Britain

Lowland Britain offers a striking contrast in many ways. Though so much less rugged, there are few parts where level land is uninterrupted by hills. One of the most extensive plains in the British Isles is in the English Midlands, consisting of river valleys and plains interspersed with scattered hills. It is the Midland Plain, which is best described as an undulating lowland rarely rising above 100 metres. To the north of it are the Pennines, to the south the Thames Basin, to the east East Anglia and to the west the Welsh Borderlands.

Another important plain in Britain is the London Basin in South East England. The master stream of the basin is Britain's second longest river, the Thames, which enters the region from the west. The Hampshire Basin includes a wide plain area of central southern England.

The geographical region described as the Lancashire and Cheshire Plain, includes the lowlands to the west of the Central and Southern Pennines. The Lowlands themselves are linked to the Midland Plain by a broad gap between the Welsh mountains and the Pennines, known as the Midland Gate. In Yorkshire, along the eastern edge of the Pennines lies the extensive Yorkshire Lowland.

The chief characteristic of East Anglia is its low relief with few hills, the area is mainly founded on chalk.

RIVERS AND LAKES

There is a wide network of rivers in the British Isles, though generally short in length and navigable but in their lower reaches, especially during high tides. Mild maritime climate keeps them free of ice throughout the winter months.

In the Middle Ages, river transport played a major role in the British internal transport system, and all the large towns of the time were situated on navigable rivers. But since the beginning of the nineteenth century the waterways, including numerous canals, have steadily declined in importance, and many have fallen into disuse.

The drainage map of the British Isles seems to contain no very clear pattern. The largest river of Great Britain, the Severn (390 km), for example, follows a particularly puzzling course. After rising on the slopes of Plynlimmon, in central Wales, it flows at first north-eastwards, but later turns sharply through the Iron bridge gorge and then runs southwards and southwestwards to the Bristol Channel. The courses of the Trent (274 km) and the upper Thames (332 km) also show many changes of direction. Many of the largest rivers in Scotland, such as the Tweed, Forth, Dee and Spey, drain directly to the North Sea. Scotland's longest river, the River Tay, some 170 km long, also follows this course. Among other important rivers, which flow eastwards, to the North Sea, are the rivers Trent, Tyne, Tees, Humber, Ouse, in England.

A number of streams flow down to the west coast, to the Irish Sea, including the Clyde in Scotland, the Eden, Ribble, Mersey and the Severn. A few small rivers flow to the English Channel.

There are many rivers in Ireland, They are short but navigable due to an abundant and even distribution of precipitation throughout the year. The longest river in Ireland is the River Shannon (384 km), flowing from north to south of Ireland. Among other more or less important rivers are the Foyle, flowing to the north, the Lagan, Boyne, Liffey, Slaney — to the east, the Barrow and the Blackwater — to the south.

Most of the British lakes are in part the result of glacial erosion and in part due to chemical solution of the underlying limestone. There is a host of small winding lakes in Scotland, in Cumbria and in Ireland.

The largest lake in Great Britain and the biggest inland loch in Scotland is Loch Lomond, covering a surface area of 70 square km, although the longest lake is Loch Ness (56 square km) which also has the greatest volume of water. In England the largest lake is Lake Windermere (the Lake District) with a surface area of 15 square km.

The largest fresh water lake in the British Isles is Lough Neagh in Northern Ireland (381 square km).

The Quaternary glaciation has further modified the river patterns in many areas. This is especially true of central Ireland, where the uneven surface of the drift cover has led, as in the basin of the Shannon, to much bad drainage, many peat bogs and numerous large lakes, such as Loughs Ree and Derg.

Date: 2015-12-11; view: 1568