Poulbruíon

Alternate name :-

Townland :-

Civil Parish :-

County :-

I.T.M. :-

Lat / Long :-

Elevation :-

Length :-

Depth :-

Faunarooska

Killonaghan

Clare

514461 x 705150

53.090082° N 009.276962° W

250 metres

0 metres

6 metres

Historical – introduction

Since the early 1980s northwestern Sliabh Eilbhe received intermittent attention from “The L.A.D.S.” (Mark Lumley, Steve Milner, Mike McDonald and author); their partially successful efforts somewhat limited by visiting annually.

As Covid-19 constraints eased, the Sliabh Eilbhe Project was resumed. December 2020 saw a solitary survey of the windswept mountain. Initial findings were somewhat confusing. Requiring checking of relevant records to identify known cave entrance locations. During this stage of the survey, using two G.P.S.R’s, each entrance was recorded as an I.T.M. map reference, (Irish Traverse Mercator). By end of January 2021, seventy new sites had been recorded. More to the point, almost each of the sites; sinks, collapses and depressions were taking, at the very least a trickle. Most sites are invisible, thrashing through the dense ground cover, until encountered. Exploring the landscape with a staff became the norm. Gradually, the landscape was examined to within the area of the two northern sinks feeding into Faunarooska, F5 and F6. Latterly, the location of the sink F5 is believed to have been successfully identified, though requires confirmation to be absolutely sure. Thus far F6 is another matter, research suggesting it is located much further up slope, toward the summit, from the limestone - shale boundary.

Theory

A large cave should exist beneath the extensive western flank of Sliabh Eilbhe. Past efforts hampered by an apparent scarcity of streams draining the shale cap slopes. Springs do exist, though small, they are utilized to supply farm stock water troughs: under no circumstance whatsoever impede or interfere with them.

Thoughts turned, yet again, to quantify rainfall for the western flank of Sliabh Eilbhe. Using the ancient Drover’s Road to conservatively limit the western boundary. Betwixt summit ridge of Sliabh Eilbhe, Pollantobar and Faunarooska exists almost one square kilometre of catchment area. Extended to the coast, it increases to six sq. kilometres.
One millimetre of rain over 1 Sq. Km equates to 10⁶ litres, (1,000,000 litres). Over six Sq. Km = 6 x 10⁶ litres; Six million litres of rain. Such a volume of rainfall goes a long way toward explaining why these steep, sloping limestone pastures, with shallow soil depth, remain fertile and lush throughout the year. Significant 24 hour rainfall events, such as 20mm, recorded Carnaun, 3rd August 2024, if similar fell on the western flank could produce 30,000,000 litres = 30,000 tonnes. Attempt to visualize 30,000 one meter cube, one tonne plastic water containers.

Site description

Poulbruíon is a shallow, narrow, linear depression, aligned almost north-south. Formed, some fifteen metres back from the edge of the low terrace, overlooking the pasture sweeping the two kilometres down to the coast. Discovered whilst conducting the long term Sliabh Eilbhe Project. This rift feature is quite similar to Pollapooka.
Permission was once again sought from the landowner, further to him previously granting permission to dig Poulfantaiseach and investigate the landscape southwards to the vicinity of F5 and F6, feeders to Faunarooska Cave.
It is a ‘busy’ area: Poulfantaiseach is one hundred, twenty metres southeast, adjacent to Halliday’s Hole, (named for Pegasus member Simon Halliday, lost whilst pushing Lancaster Hole, terminal sump). Pluais Gabhar, (aka Goat Hole), is located near the top of a rugged valley, giving the appearance of a significant geological fault. Around the upper, southern end, of this fault is a cluster of sites, in addition to those mentioned above. Further to these sites, some recorded as lost, between late 2020 and early 2021, over seventy other sites were recorded, consisting of sinks depressions and collapses. The Project covers a large area owned by multiple landowners; permission must be sought prior to any visit.

Image showing sites immediately adjacent the south end of the apparent fault.

Digging

Poulbruíon was accurately recorded 21st August 2023, work commencing 28th October 2023. Bushes, cultivated, to prevent stock incursion, were cleared. Replacement prevention to avoid harm to stock set in place. Reviewing the site the deep part of the rift chosen to sink a shaft was a fortunate choice. This point appears a boundary, separating the south, silt and clays and occasional boulders. From the northern, compacted boulders, tight against each other, their gaps filled with dense compacted clays. August 2023, work continues…

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