Derryvree’s Silted Tundra – Emerald Archives

Dateline

The label 31,857 BCE is useful only as a modern point of reference. No community in Ireland counted years in this way, and neither archaeology nor Quaternary science can identify an event that happened in one particular year so deep in time. Arithmetically, it corresponds to roughly 33,800 calendar years before present, where “present” in radiocarbon convention is 1950. The appropriate setting is the later Middle Palaeolithic world of Marine Isotope Stage 3: an unstable cold period before the Last Glacial Maximum, when environments, sea levels and ice margins could change greatly over centuries and millennia. The evidence closest to this nominal date is therefore environmental and faunal, not historical in the usual sense.

Dating a Landscape, Not a Year

The most important Irish archive for this broad interval lies at Derryvree near Maguiresbridge in County Fermanagh. Roadworks in 1969 cut through a drumlin and exposed organic silts and fine sands trapped between two separate beds of glacial till. Such a sequence matters because it records a time when water, plants and animals occupied ground that was later overridden or enclosed by ice-derived sediment. The organic layer produced a radiocarbon determination of 30,500 years before present, with a large original uncertainty of roughly a millennium either side. The deposit is not a diary entry for a single season, still less for a single calendar year; it accumulated over time and its date must be calibrated against changing atmospheric radiocarbon levels.

When discussed in calibrated terms, the Derryvree evidence is commonly placed within a broad range of approximately 36,900–31,700 calendar years before present. That span overlaps the modern numerical point represented by 31,857 BCE, but overlap is not identity. It permits a responsible conclusion that parts of northern Ireland had recently been, or could still have been, ice-free during this wider interval. It does not prove that the Derryvree basin was open on the exact notional year, nor that the same conditions applied without variation across the whole island. The distinction is essential: sediments give dated evidence for environmental phases; historians’ annual chronology does not yet exist here.

Open Country in Fermanagh

The fossils preserved at Derryvree point to a full-glacial, periglacial environment: cold, open and largely treeless. Rather than imagining the familiar green and wooded Ireland of later millennia, it is better to picture a low, exposed landscape of mineral ground, wet hollows and shallow freshwater, with tundra vegetation adapted to short growing seasons. Organic silts, pollen, plant remains and small animal evidence are the basis for that reconstruction. “Tundra” is an interpretation of several proxy records, but a strongly supported one; the original investigators concluded that open tundra vegetation and a periglacial climatic regime prevailed around the basin.

This was not necessarily an unchanging white desert. A periglacial landscape could include snow cover and frozen ground in winter, summer thaw, sedge-rich wet places, streams and ponds, and patches of vegetation sufficient for grazing animals. The word “muskeg”, used in discussions of the Derryvree deposits, conveys wet, peaty ground rather than a dry steppe. Seasonal contrasts may have been marked. Yet the available Irish evidence cannot provide a reliable temperature for this particular year, nor can it tell us exactly how long any particular pond lasted. What it securely shows is that life persisted between episodes of glaciation, and that the later drumlin landscape conceals fragments of an earlier, colder living world.

Ice Was Advancing, Unevenly

At roughly 33,800 calendar years before present, Ireland stood before the principal expansion of the last British–Irish Ice Sheet. Modern reconstructions stress that ice-sheet growth was neither simple nor simultaneous. Ice was already established in northern and upland areas of Britain and Scotland; from about 31,000 years ago it grew rapidly and spread across Ireland and Britain, eventually extending over much of the continental shelf. The maximum overall ice-sheet extent is reconstructed at about 26,000 years ago, not at the date considered here. Thus 31,857 BCE belongs to a threshold period: cold conditions and local ice histories mattered greatly, but it should not be presented as though every Irish valley was already buried beneath the later maximum ice cover.

That uncertainty also affects the map. Lower global sea levels exposed extensive areas now beneath the seas around north-west Europe, while ice loading depressed parts of the crust and altered relative sea level locally. It would be rash to draw a simple, continuous land bridge into a scene set at this date. Research on Ireland’s changing insularity shows that the existence, height and usefulness of possible routes depended upon time, local topography and sea level; the better-known later connections and disconnections cannot simply be projected backwards. People or animals might have moved through a changing wider landscape, but a particular route to Ireland around 31,857 BCE has not been demonstrated.

Animals at Castlepook

Southern Ireland supplies another crucial, though differently complicated, body of evidence. Castlepook Cave near Doneraile in north County Cork has produced a rich assemblage of Pleistocene animal remains, collected principally during antiquarian and early twentieth-century excavations and reassessed through the Irish Quaternary Fauna Project and later work. Reindeer, red deer, giant deer, brown bear, hare, fox, wolf, spotted hyaena and woolly mammoth are among the animals associated with the cave’s Ice Age deposits or collections. The assemblage establishes that southern Ireland formed part of a changing north-west European cold-stage faunal world during portions of Marine Isotope Stage 3. It does not demonstrate that every species named was alive together, or at Castlepook, in the nominal year under discussion.

Recent radiocarbon reassessment has made the cave more important and more difficult to summarise. Improved pretreatment of bone collagen showed that some older determinations for southern Irish fauna were substantially too young. The revised results suggest that certain animals, notably giant deer and spotted hyaena, may have disappeared locally before the Last Glacial Maximum, around 40,000 calibrated years ago. That finding cautions against assembling an attractive but false snapshot of a single “Irish Ice Age fauna”. Castlepook instead records repeated episodes of animal presence, carnivore activity, bone transport and preservation within a cave system over a long period.

The Human Question

The possibility of people in Ireland at this depth of time centres on a reindeer femur from Castlepook. Re-examination identified a mark interpreted by Ruth Carden as a cut made with a sharp stone tool during butchery; the bone has been publicised as dating to about 33,000 years ago or, in an approximate BC rendering, around 31,000 BC. If that interpretation is accepted, it would indicate a fleeting Upper Palaeolithic human encounter with reindeer in Ireland well before the peak of the last glaciation. It would not, however, establish a permanent settlement, a named population or a continuous ancestry leading to later Irish communities.

The limits are as significant as the possibility. The marked bone came from an old cave collection rather than a modern, tightly excavated occupation surface. No securely associated lithic toolkit, hearth, dwelling, human remains or repeated domestic debris has yet supplied the fuller archaeological context that would turn a modified bone into an indisputable settlement site. The cave may even have received discarded or scavenged bones carried by carnivores after an animal was processed elsewhere. Renewed excavation at Castlepook has sought undisturbed Pleistocene deposits precisely because stratified finds, direct dating and detailed taphonomic study are needed to test these questions. The evidence is intriguing and potentially transformative, but it remains evidence for a possible episode, not proof of an Irish society in 31,857 BCE.

What Cannot Be Recovered

There were no recorded kingdoms, political institutions, treaties, raids or diplomatic exchanges in Ireland at this date. Nor is there evidence from which to identify religious practice, language, art, formal learning, trade networks or social rank. To fill these headings with imagined hunter bands, shamans, chiefs or tribal territories would give fiction the appearance of history. Even if a small Upper Palaeolithic group reached Ireland, its social arrangements cannot be reconstructed from one contested or provisional trace. Comparisons with contemporary hunter-gatherers elsewhere in Europe can suggest possibilities—small mobile groups, seasonal movement and skilled animal processing—but they are analogies, not Irish facts.

The most defensible account of everyday life is therefore environmental. Reindeer and other large herbivores would have found food in open vegetation; predators and scavengers used caves and carcasses; freshwater basins accumulated the sediments that now preserve clues to plants, insects and climate. If humans were present, animal resources may have been central to survival, and mobility would have been more plausible than villages or farms. But neither farming, pottery, monuments nor settlement structures belong to the evidence for this period. Ireland’s documented prehistoric sequence begins much later, after deglaciation, and cannot be read backwards into this Ice Age interval.

A Record Beneath the Drumlins

The significance of Ireland around 31,857 BCE lies not in an invented event but in a rare survival: organic sediment beneath a drumlin, cave bones recovered from Cork limestone, and a landscape whose later ice cover erased far more than it preserved. Derryvree shows that cold, open, living terrain existed in northern Ireland within a broad date range overlapping this point. Castlepook shows that Ice Age mammals occupied southern Ireland during related but not necessarily identical phases, and it raises a serious, unresolved question about early human visits. Together they replace the misleading notion of a timeless frozen emptiness with a more compelling reality: a changing land at the edge of advancing ice, intermittently habitable for plants and animals, and perhaps briefly entered by people whose presence has barely survived.

Primary Sources

Tags: County Cork, Derryvree’s Silted Tundra, Early Holocene, Ireland Year by Year, Irish Ice Shee, Last Glacial Maximum