The Cade Fields is the most extensive Stone Age monument in the world dating from 5000-6000 years ago. and lies Beneath the wild unspoilt bogland of North Mayo.
Megalithic burial and ceremonial monuments survive in many areas of Ireland and Western Europe, but little or nothing remains of their contemporary landscape. North Mayo not only has the greatest concentration of court tombs in the country but, uniquely, the entire layout of the associated farmed countryside. The story of the Ceide Fields (Ceide in Irish means “a flat topped hill”) is not just the story of the oldest known enclosed landscape but is also that of a changing climate and natural environment over several thousand years.
The Neolithic or Stone Age farmed landscape which is the Ceide Fields dates to between five and six thousand years ago. It consists of ten square kilometres of enclosed farmland divided up into regular field systems bounded by dry stone walls as well as dwelling enclosures, which survived under the blanket bog. On Ceide hill the fields are the most regular, indicating they were carefully measured in a large scale and highly organised operation. A series of parallel walls over 1.5km long divide the land into long strips, varying from 90m to 150m in width. To the west of the Ceide Fields Visitor Centre these walls seem initially to follow the contour of the Behy valley and then continue over the spur of the hill, merging with a second similar parallel system following the alignment of the Glenulra valley. This continues onto the next hillside. Despite “meanders” in the walls, the parallel strips remain remarkably consistent in width. Each strip of land was subdivided by “cross walls” into rectangular fields, but these cross walls do not continue directly from one strip into the next.
Most of the fields are quite large, up to several hectares in size, and were used as pastureland. At that time, the climate was on average up to 2°C warmer than today, and this would have resulted in grass growth for at least eleven months of the year, allowing permanent grazing for cattle. A few smaller more irregular shaped fields in the vicinity of the Visitor Centre may have been used for growing cereal, probably emmer wheat. Excavations prior to the construction of the Centre uncovered some plough marks, or grooves in the subsoil made by an ard or primitive plough while cereal pollen was identified in samples of the soil filling the grooves. Areas of stone clearance and some lynchetting (fine loose soil washed downslope), may also indicate tillage. A broken stone tip of an ard was found in the same area and one had also been found in the dwelling enclosure. A saddle quern used for grinding the corn was found on the east side of the Glenulra valley.
The field walls were originally uncovered during turf-cutting in the 1930′s at Belderrig by a local schoolteacher, Patrick Caulfield. However, their significance only became apparent when his son Seamas began their archaeological excavation a few decades later. An old technique of probing the bogs with metal rods to locate tree stumps was used to locate the stone walls, which are still totally hidden beneath up to 4.5m of bog. The walls are not confined to the Ceide Fields but extend 7km to the west as far as Belderrig. Beyond Belderrig there is a gap in the archaeological remains for a further distance of 15km. It appears that the bog was already well established there by Neolithic times, as indicated by radiocarbon dating of pine stumps preserved in the bog. Further west, in the area north of Carrowmore Lake, pre-bog Neolithic field boundaries, including some earthen banks, have been located.
To the east of Ceide Fields the Neolithic landscape extends to the south and east of Ballycastle as far as Rathlackan, 15km away. Here a complex of field walls and house structures of various shapes and sizes have been found. Excavations at Rathlackan revealed a fine three chambered court tomb. A 20m diameter enclosure, surrounding a small 3m wide stone square shaped house was built onto its side. The only gaps in the pre-bog field systems between Ceide Fields and Rathlackan are in low-lying areas such as around Ballycastle where hog never developed. However the existence of court tombs in this area provide evidence of Neolithic occupation.
The pathway to the rear of the Visitor Centre follows the outline of a field, two hectares in size. The bog has been excavated in places, exposing the walls on the Neolithic land surface. When built, these walls were quite substantial, and at least lm high, but had generally collapsed before the bog formed. The walls have been left as they were discovered so that what you see are stones that have not been moved in over fifty centuries. Where the walls have not been excavated, white stakes mark their location.
Within this rectangular field a separate oval shaped stone walled enclosure, measuring 25m by 22m was excavated by Dr Seamas Caulfield in 1970 and 1971. Within the enclosure, the portholes of a round house about 6m in diameter were found. The house would have been constructed from wood and other organic materials, which have left no trace. Typical habitation debris of Neolithic round-based pottery and stone material mostly of chert, as well as charcoal from a hearth indicated this was a dwelling house of a single family. The enclosure wall is similar in construction to the field walls and would probably have served to exclude farm animals rather than being a defensive structure. Similar enclosures in other strips of land are presumed also to be dwelling enclosures and they show a settlement pattern of dispersed single-family dwellings, with each family possibly owning or using one strip of land.
Down the slope from the dwelling enclosure, a small egg shaped stone walled structure, 7m by 4m, incorporating part of the cross wall was discovered during excavations of the field walls prior to the construction of the Visitor Centre. At first it was thought to be a dwelling house but showed no evidence of this when excavated. It may have been used as an animal pen.
The vast area of bogland forming a soft blanket over the landscape from cliff edge to hilltop in north Mayo today is a result of the continually damp but mild climate. Here there is well over the minimum of 1,250mm of rain spread over at least 225 days per year required for the growth of blanket bog in Ireland. This is a very different vista and climate
to what our Neolithic ancestors encountered nearly six millennia ago. They would have found a forest of predominantly pine and birch with some hazel, oak, willow and alder in a drier and warmer climate. However, some low-lying areas such as that west of Belderrig and a small basin about 100m diameter in Glenulra were already covered by bog. Detailed analysis of the pollen preserved in a deep core through this basin has revealed much about the changing environment. Peat preserves pollen and so counting the various species of pollen found at any particular level in the core will give an indication of the trees and vegetation growing in the vicinity at the time the bog was at that level. These levels can also be dated by radio-carbon analysis. The Neolithic farmers cleared most of the forest in order to lay out 4,300 year old pine tree in Visitor Centre. Some trees were undoubtedly kept to provide such resources as firewood, materials for building, baskets, tool handles and food such as hazelnuts. Huge increases in the amount of pollen from grasses and herbs such as ribwort plantain, dock, buttercup, dandelion and white clover in the peat core confirm the archaeological evidence for extensive pastureland.
After about five centuries, however, changes to a cooler, damper, climate came about. This lead to the widespread expansion of the blanket bog leaving their way of life unsustainable. The fields were abandoned, maybe over a couple of generations, and, when not kept maintained, the stone walls collapsed bit by bit and quickly became hidden under the bog vegetation. There was some regeneration of woodland and, later, a widespread colonisation of the bog by pine trees, many of which have been preserved in the peat. These include the magnificent example from Patrick Caulfield’s turf bank in Belderrig, which forms the centrepiece in the Visitor Centre. The pine forest died out about 4,600 years ago due to increased wetness in climate and since then the ever deepening bogland would have appeared much like today.
The overall significance of the Ceide Fields is that they reveal a unique insight into a highly organized farming system. A population of a few hundred people in the Ceide Fields area alone were living in a peaceful settled community for five centuries from about 5,700 to 5,200 years ago. Initially the communities co-operated in clearing the forest and dividing 1,000 hectares of land amongst the families, indicating a high degree of social development. A major question is whether these field systems were unique at the time or are simply unique in their preservation.