Frank Mitchell (1912–97) was a distinguished but unassuming academic, environmental historian, archaeologist and geologist. While he had many academic writings his best known book was The Irish Landscape (1976) about which he was typically modest. In 1990 Mitchell published ‘a semi-autobiography’ The way that I followed. The title was a play on Robert Lloyd Praeger’s, The way that I went (Dublin, 1937). Praeger in his peregrinations was less kind to Laois and Offaly than Mitchell with Praeger’s observation that neither county need detain us long (p. 235) and ‘there is not much of special interest’ (p. 237). Westmeath he found to be more hospitable than Offaly having less than half of the amount of bog in Offaly and more pasture. We may look at the Praeger account in another blog
Someone who Mitchell would have known (at TCD) and admired was the geographer T.W. Freeman. The latter’s Ireland a general and regional geography (1950, third edition, 1963) provides a valuable account of the boglands east of the Shannon and the eskers of the Central Lowland with a brief disquisition on the market towns ‘that differ so strangely in their material prosperity’ Freeman was fascinated by the unexpected and haphazard nature of economic life in some of the towns – he seems to have had in mind Tullamore and Clara. In any case let us go back to look at what Mitchell wrote of the terrain of east Offaly Shannon as part of this Grand Canal series.
From The way that I followed, pp 233–36.
CROGHAN
Twenty-six kilometres east-north-east of Athlone, the Hill of Uisneach, an isolated relict knob or hum of limestone, rises to a height of 180m. It is reputed that on a clear day twenty of the thirty-two counties of Ireland can be seen from its top, and throughout prehistory and history it has been a very important site, with many remains of antiquities.[1] Praeger and Macalister excavated here in the twenties, though not with any distinction. A large erratic boulder, now surrounded by a circular earthen bank, was described by Giraldus Cambrensis as the navel of Ireland. [Birr made this claim also]
I prefer to give this title of distinction to another upstanding isolated hill, Croghan, which lies near Daingean, 25km south-east of Uisneach. Croghan, which rises to a height of 230m, is a mass of volcanic rock. The rock was formerly embedded on the local limestones, but as erosion lowered the surface of the limestone, the more resistant volcanic rock held its level. Its antiquities show that it too has been frequented by people for a very long time, but they are less impressive than those at Uisneach.
I choose Croghan, because although it may not be at the geographical centre of Ireland, it lies in the heartland of the great raised-bog of the midlands; bogs which reach an elevation of 100m lap up against it on all sides. I do not know how many counties are visible from its top, but the cooling-towers of at least four peat-fired generating-stations can be seen. In addition, it emphasises for me once again the fantastic drainage pattern of Ireland. I am sure that before man stated his attack on the bogs, a continuous ring of living bog surrounded the hill. From the bog on the west water drains away to the Shannon and to the Atlantic; the bog on the north-east sends its surplus water to the Boyne and the Irish Sea, while water on the couth-east goes to Barrow and the Celtic Sea. Each of these rivers has to abandon open country, and negotiate a rocky gorge before it reaches the sea; the Shannon at Killaloe, the Boyne below Navan, and the Barrow below Graiguenamanagh.
CLONSAST BOG
I feel I should have written an account of The Rape and Cremation of an Irish Raised-bog. Clonsast bog was one of the largest and finest of Irish raised-bogs, and so it was early marked out for development by Bord na Mona.
The bog lies about 7km north of Portarlington, and while in places it merged into other nearby bogs, it was essentially an independent unit, about 6.5km long and 4km across. The peat was 6m deep, and its domed top rose to about 10m above the surrounding countryside. I saw it first in 1938 when I walked it with Tony Farrington, Felix Hackett, a professor in University College, Dublin, and a man of very wide scientific interests, and some members of the staff of Bord na Mona.
The top of the bog was very wet and quaky, and here I was glad I had mastered the art, necessary for bog survival, of walking with one’s weight on the foot in the air. There was an extensive system of very large pools, known locally as the Duck Loughs, because they were used as a refuge by wildfowl in the winter. Discussing the ponds someone suggested that they were fed by deep springs at the bottom of the bog, but this seemed unlikely. The origin of these pools is not clearly understood. In some bogs they are aligned with one another, and suggest expansion-tears in the living membrane of vegetation that clothes the bog surface.
At times raised-bogs appear to be overcharged with moisture, and some of this escapes by sub-surface channels, which may have a tunnel-like exit towards the bog margin. Such exits are called soaks, and Clonsast had one splendid example near its south-west margin, from which water emerged so steadily that it was marked as a river on the OS map. Today, alas, opportunities for further study of this feature in Ireland have vanished, as most of the big bogs with good pool systems and soaks have been developed.
To initiate development at Clonsast an extensive series of drains and development trenches were cut into the bog surface, which gradually sagged towards the cuts as water drained away. After some time the surface became firm enough to carry complicated peat-harvesting machinery. The mechanical engineers of Bord na Mona showed considerable ingenuity in design, as the machines had to be as big as possible, so as to handle large quantities of material, without at the same time becoming so heavy that they would sink into the bog. These machines aroused wide international interest.
An electricity transformer station was erected flush with the bog surface, supported on columns which went down to the soil below the bog; as the years went by it was amusing to watch the station appear to climb higher and higher into the air, as the peat around it continued to sink. Much of the peat-winning machinery was powered by electricity, and it always seemed to me to smack something of the pelican engrailing in that some of electricity produced by the bog had to be fed back to it to further its own destruction.
Sad as the destruction of the bog was, the sections cut into it afforded a wonderful opportunity to study the phases of its development. But the times could have been a little more favourable; it was in the war years, and cars had disappeared, and with them one might think the possibility of transporting my relatively heavy drilling-rods. Unfortunately I came across a photograph in a paper on bog survey in Sweden, which showed a keen worker with the rods strapped to the bar of his bicycle, and I realised I was still mobile. I found cycling with the loaded machine rather hazardous, as the centre of gravity was high, and one had to bend one’s knee first outwards to get round the rods, and then in again to reach the pedal. So I continued to work at Clonsast cycling out from the hotel in Portarlington. Once at the bog matters were easier, as the bog was now covered with a light railways, and the workers at the depot were very accommodating about running me out to the various parts I wished to visit. Levelling presented no problem as the bog had been very accurately surveyed.
About 7500 years ago woods in which pine and yew were common covered the area. Progressive formation of peat nearby was steadily blocking the local drainage system, and waterlogging killed off the trees which gave way to fen plants. After these had formed about 2m of fen-peat, they could no longer get sufficient nutrient from the soil below, and they gave way to plants of the Sphagnum moss community, which could gain all its needs from rainwater. At first peat-growth was slow, and decayed moss-peat built up to a thickness of about 1m. Bog-growth then accelerated, and about 3.5m of fresh moss-peat built up the upper layers of the bog-dome.
Unfortunately for the Bord, this simple pattern of growth had been interrupted by climatic periods when bog-surface became drier, and the trees which had been driven out reinvaded the surface. Renewed bog-growth killed off the trees, but they left behind a horizon of tough, often interlaced, tree stumps, which caused great problems for machines designed to slice up soft wet peat. This was a problem the Bord were to meet over and over again throughout the country.
The last major invasion by trees was about 4000 year ago, and in that invasion pine was prominent. After that pine dropped back in Ireland, though it did survive at least into the early centuries AD in some localities. It was then that it made a last feeble invasion of the bog surface at Clonsast. In one restricted area I saw a lot of uprooted small pine trees. At first sight they looked like weeping willows that some vandals had torn up in a nursery-garden. But closer examination showed that the projections that curved away from the stems were roots, not branches. The pines were trying to grow on a wet bog-surface; as tree-weight increased, the stem sank into the bog bringing the roots down into an over-wet layer. The roots responded by trying to climb back to the surface, with the result that when pulled from the bog the young tree looked like an umbrella inside out.
By 1988 the development of Clonsast bog had run its full cycle, and the power-station near Portarlington was dismantled. That operation brought its own problems. In the forties asbestos was perfectly respectable building-material, and it was used in parts of the station. But by 1988 asbestos was a dirty word, and its removal and disposal caused difficulties.
But the greatest problem was the ‘cutover’, the derelict area from which the peat had been removed. Strenuous experiments were carried out to see how best to reclaim the area. A dairy farm was set up, vegetables were grown, trees were planted. The possibility of ‘biomass’ production, that is the growing of woody bushes which would be harvested mechanically at a young stage and burned to produce electricity, was considered. But one is forced back again to the observation Charles Smith made in Cork over two hundred years ago: ‘It may be a question, whether the labour and expense will not be more than the value of the land, after it has thus been reclaimed?’ The European Community does not want more land, certainly not poor-grade land, and the wisest course is probably to let the cutover revert to the wetland from which it started. Possibly the slow cycle of raised bog development might begin all over again.
[1][ See, for example, Edel Breathnach, ‘St Brigit – who was she? History Ireland, vol. 32, no. 2 (March-April 2024), pp 14-17. ]
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