Poulacapple Project

This overview presents the results, to May 2026, of prospecting Poulacapple Mountain, upon mothballing Poulbruíon dig, (Sliabh Eilbhe Project). Ongoing work is represented by regular Pegasus Club Nottingham log book entries taken from the author’s Personal Logs.
The Burren Way public footpath meanders within twenty metres of Poulacapple Pot, descending from the summit to the Feenagh Road, adjacent flows the intermittent Rathborney River. The majority of new sites have developed along the northeastern slopes of Poulacapple Mountain. Logistical issues arise from the remoteness of dig sites - conveying heavy timber, tools and galvanised scaffold shoring, takes a significant amount of time and effort. A factor that will affect associated issues, such as L227, a large steep sided, ancient sink, requiring a walk in of almost a mile from the nearest parking spot. Once again, prior to commencement, permissions were sought and eagerly granted to members of The Pegasus Club Nottingham.

Introduction

Among the surprisingly few recorded caves near the summit of Poulacapple Mountain, Poulacapple Pot may rightly be considered a prime site. A substantial sink, potentially offering 300 metres of depth and 7 kilometres of distance, issuing from its believed submarine resurgence off shore of Ballyvaughan. Over the previous decade enquiries realised the adjacent sites of Gragan West Cave, Green Stream Cave and The Green Grove attract lesser interest, likely due to difficulties locating entrances among the dense, natural ground cover. Their small entrances, in overgrown depressions, are scattered across ankle wrecking terrain, conditions proving problematic in the 1970s, on attempting to establish a cave entrance map reference using a compass, experience shows a compass is not up to the precision demanded in such a landscape, with the few available landmarks to sight to.

Relief Map of Northwest Clare, The Burren

Source, Archaeology.ie

Navigation

G.P.S.R. (Global Positioning Satellite Receiver), software systems are widely accessible; mobile phone users may also enjoy this time based navigation facility, reducing time and effort locating oft obscure entrances in featureless landscapes.
The Irish Ordnance Survey Grid, (1965), is being gradually replaced by ITM, (Irish Traverse Mercator), a far more accurate system. Yet, use of electronic navigation is only practicable if a precise cave entrance map reference is available, and the GPSR or mobile phone, has enough battery charge for the entire trip.
Pegasus Projects often deploy GPSR’s in pairs to obtain maximum precision - most commonly used are the Garmin Oregon 300, Garmin GPSmap 62s and the Garmin GPSmap 64s. Such precision is pursued to assure confidence for inclusion in the Pegasus Cave Entrance Database, (PCED): upon completion the database will be complementary to any visiting the Burren, hopefully encouraging the prospecting of areas hitherto overlooked, or believed without obvious potential, to be examined.

View east, L227, a sink. Photo: Paul McGrath

Map referencing

Attempting to convert Irish National Grid (IRNG) directly to ITM, and visa versa, will produce errors, due to inherent errors in the Irish National Grid (1965). Accuracy, on converting, may only be assured by converting firstly to Latitude and Longitude then to the chosen destination.

Irish National Grid (1965) – Latitude/Longitude - Irish Transverse Mercator.

The website below can also offer conversion to another navigation software system, ‘That Three Words’.

The following website may be of some assistance. https://irish.gridreferencefinder.com/

Prospecting

On resuming work at Poulacapple Pot, (2025), and subsequent, albeit temporary setback, a systematic examination of nearby depressions revealed several steep sided, conical shakeholes up to 7 metres deep. Multiple surface, and shallow sub-surface conduits seem to drain toward Poulacapple Pot, yet appear to drain southwest opposite to the believed submarine resurgence at Ballyvaghan, six kilometres northeast.
On a brief visit onto adjacent private land, within an hour, several unrecorded speleological features were encountered. Their presence in a karst landscape, close to Poulacapple Pot, prompted the owner be swiftly sought, a telephone conversation produced permissions. The next day, on meeting the owner, his enthusiasm was obvious. Over the following week 94 features – depressions, large and small, springs, collapses and one small resurgence were recorded. Such numbers of sites, increasing on an almost weekly basis, presented issues of individual site identification, therefore a numerical system, prefixed ‘L’, was applied, adopted in the 1980s by the ‘L.A.D.S’, (Let’s ‘Ave a Drink Speleo’s).

View Southeast, L199, Bedding top right. Photo: Paul McGrath

Recording Sites - Assigning an ID

When recording an entry to a GPSR it automatically assigns its own numeric ID – when downloaded to a computer each entry may then be edited, at this point its unique (L) identification number is assigned simultaneously with its I.T.M. map reference. It is understood some electronic equipment cannot access the ITM system, therefore a Google Earth system, Decimal Degrees, is being added as an adjunct, this extra level of service will, however, take some time to complete.
It should be clear, this project has - grown legs – and must be considered a dynamic work in progress. Log Book entries by the author - recording regular progress, will occasionally have accompanying aerial images, that may show the GPSR assigned number, such representations are working images, and not finished images.
Each speleological feature has been recorded to identify potential drainage patterns, normally obscure in the wider, wilder, landscape – this approach successfully identified one sink, L118. Here, two lines of features, curvi-linear linear, the other linear, converge at the base of a low limestone terrace face. Its excavation offers an insight of formation, and subsequent deposition of stratified clays, minerals and course gravels, with an east wall of bedrock.
Shoring the unstable ground, though time consuming, has been made straightforward bracing the galvanized and timber shoring off the eastern wall of bedrock. It is possible the narrow entry may present issues removing larger boulders, yet, so far the crystalline structure of the limestone, when struck with a sledge hammer, fractures reasonably easily.
Another identified pattern led the Team to L199 - a shallow dig down through a boulder filled hole, in the base of a five metre deep, steep sided, conical depression, is leading towards a bedding. (see above image)

Poulacapple Project, as of May 2026

As the Project expanded southeast, along the edge of the summit, it approached the vicinity of Green Stream Cave, (GSC), The Green Groove, (TGG) and Gragan West Cave, (GWC). To avoid ‘rediscovering’ known sites prospecting was suspended whilst the nearest, GSC was located, and precise map reference established, being ninety metres NNW of its 1970s recorded position, among numerous depressions, deep, dense, heather, briars and grasses, its ten metre diameter depression lay athwart the townland boundary of Cahermacun and Gragan West.
Mid-May, ENE of GSC, another ancient resurgence has been identified, downstream of which is large, now, dry sink, L227. Though previously assured of encountering no trespass issues traversing the mountain by the Farmer, this southern extremity makes the author uneasy, requiring confirmation of the Farmers ownership, and/or permission from his neighbour, before further work is conducted.
From Poulacapple Pot the Project has also expanded, anti-clockwise, from the northern summit contour toward Cullaun Zero-1, this area also requiring the Farmers confirmation, or clarity of actual ownership.

Pat Cronin 3rd May 2026

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