An Outline Geography of Ireland

An Introduction to Ireland's Geography

 

Introduction
Ireland is an island on the western fringe of Europe between latitude 51 1/2 and 55 1/2 degrees north, and longitude 5 1/2 to 10 1/2 degrees west. Its greatest length, from Malin Head in the north to Mizen Head in the south, is 486 km and its greatest width from east to west is approximately 275 km. Since 1921 the island has been divided politically into two parts. The independent twenty-six county area, comprising 70,282 sq. km, has a population of 3,523,401 (1991). Northern Ireland, which is part of the United Kingdom and contains six of the nine counties of the ancient province of Ulster, has a population of 1,569,971 (1991). In 1973 Ireland became a member of the European Union (EU).

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Physical Landscape
The two great mountain systems of Europe, north of the Alps, converge westwards to meet and mingle in Ireland. The older (Caledonian) extends from Scandinavia through Scotland to the north and west of Ireland, where it gives rise to the rugged and mountainous landscapes of Counties Donegal, Mayo and Galway. The higher mountains are of quartzite which weathers into bare, cone-shaped peaks such as Errigal (752 m) in Donegal, Croagh Patrick (765m) in Mayo and the Twelve Bens in Galway. Structures of similar age are responsible for the Wicklow and Blackstairs mountains which extend south-westwards from Dublin Bay for a distance of more than 100 km. In these, long-continued denudation of a great anticlinal structure has exposed a granite core which now forms rounded peat-covered uplands, the crests being notched in places by glacial cirques. The mountains are penetrated by deep glacially modified valleys of which the best known is Glendalough in County Wicklow.

The younger structures (Armorican) extend from central Europe through Brittany to southern Ireland, where they reappear as a series of east-west anticlinal sandstone ridges separated by limestone or shale-floored valleys. The hills rise in height westwards culminating in Carrantouhill (1041 m) in the Magillycuddy Reeks, the highest mountain in the country. The famous Upper Lake of Killarney nestles in the eastern slopes of this range. The valleys separating the western extension of these mountains have been flooded by the sea, giving rise to a number of long deep inlets.

In north-eastern Ireland basaltic lavas spread widely over the existing rocks in Eocene times and now form the bleak plateau of east Antrim. Westwards the basalt is downwarped and the resultant drift-covered lowland is occupied in part by Lough Neagh, the largest lake in Ireland.

The heart of the country is a limestone- floored lowland bounded on the south by the Armorican ridges and on the north and west by the Caledonian mountains. This lowland is open to the Irish Sea for a distance of 90 km between the Wicklow Mountains and the Carlingford peninsula, giving easy access to the country from the east. It also extends westwards to reach the Atlantic Ocean along the Shannon Estuary, in Galway Bay, in Clew Bay and again in Donegal Bay. Numerous hills break the monotony of the lowland which rises westward towards the coast in County Clare where it terminates in the cliffs of Moher, one of the finest lines of cliff scenery in Western Europe.

Much of Ireland was covered by ice during the Pleistocene period. This ice finally melted away about twelve thousand years ago, leaving behind evidence of its former presence in most of the minor physical features of the landscape. Throughout the greater part of the lowland the bedrock is hidden by glacial deposits which, in the north central part of the country, form a broad belt of small hills (drumlins). The glacial cover also modified the early drainage pattern and in places created groundwater conditions which facilitated the growth of peat bogs.

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Rivers
The lowland is drained by numerous slow- flowing streams, the largest of which is the River Shannon, 340 km in length. In its middle course this river broadens into a number of attractive lakes but as it approaches the sea its gradient steepens. This is the location of Ireland's earliest hydro-electric power scheme. The main rivers draining eastwards are the Lagan, which flows into Belfast Lough, the Liffey, with Dublin at its mouth, and the Slaney, which enters the sea at Wexford. In the south of Ireland the long east-west synclinal valleys are occupied by such rivers as the Suir, the Lee and the Blackwater which reach the coast by making right-angled turns to pass southwards through the sandstone ridges in narrow gorge-like valleys.

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Climate
Ireland's mild and equable climate is a reflection of the fact that its shores are bathed by the relatively warm ocean waters of the North Atlantic Drift. Valencia, in the extreme south-west, has an average January temperature of 7¡C and a July temperature of 1 5¡C, a range of only eight degrees. The figures for Dublin are 4.5¡C in January and 1 5.5¡C in July, a range of eleven degrees. Extremely high or low temperatures are virtually unknown.

Rainfall is heaviest on the westward facing slopes of the hills where it may exceed 3,000 mm in Kerry, Mayo and Donegal. The east is much drier and Dublin records on average only 785 mm annually.

The outstanding feature of the Irish weather is its changeability, a characteristic which it shares with all the countries that lie in the path of the temperate depressions. However more stable atmospheric conditions may arise in winter with the extension of the continental high pressure system bringing clear skies and cool conditions, especially to the eastern part of the country. In summer an extension of the Azores high pressure system may bring periods of light easterly winds and bright sunny weather.

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Soils
Most of the soils of Ireland are derived from glacial drift and reflect its varied composition and texture. There are large areas of fertile grey-brown podzolic soils on the better drained parts of the lowland. These give way to less fertile acid brown earths where the parent material is low in lime or to gleyed soils where the drainage is poor. Thin acid peaty soils are widespread on the hills.

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Vegetation
The visitor to Ireland is immediately impressed by two aspects of the vegetation cover. The first is an impression of intense greenness, the result of the abundant grasses responding to the mild moist air. The second is the relative absence of trees, especially along the western seaboard where strong winds are the main limiting factor to growth. The once extensive oak woodlands of the midlands were cleared over most of the country by the seventeenth century and remain today only as remnants in remote areas. The flora is of more limited variety than elsewhere in Europe but it has some interesting features. In the extreme south- west (Cork/Kerry) there is a vegetation with Mediterranean affinities which includes the Arbutus. The numerous bryophytes and lichens reflect the mildness and high humidity of this part of Ireland. In the Burren in County Clare an Arctic-Alpine flora survives from a colder period in the past.

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Fauna
Apart from seals which breed around the coast and whales which occasionally visit coastal waters, Ireland has twenty-seven species of mammal. These include the red deer, pine marten, badger, otter, hare and stoat which are native to the country, as well as introduced species such as the fallow deer, rabbit and other rodents. Ireland's only reptile is a small lizard and there are three amphibia, the newt, the frog and the toad. The rivers and lakes have salmon, trout, char, pollan, perch, pike and eels. Of the three hundred and eighty species of wild bird recorded in Ireland, only about one-third breed in the country.

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People
Ireland has been inhabited since Stone-Age times and for more than five thousand years has been the recipient of peoples moving westwards across the European continent. Each new group of immigrants has contributed something to its population and culture and no group ever entirely obliterated the character of the earlier ones. It is these diverse elements that have come together to form the distinctive Irish nation of today.

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