A small surface hole opens after 10m into a wide, flask-shaped chamber, descending a further 42m to the floor. The waterfall from Polliniska enters at the base of the ‘neck' of the flask and pours on to the floor at its northern end before draining south to a second waterfall that pours over boulders to a lower floor. Part way down this descent, on the right, an extended crawl called Paris Passage leads south for 85m to mud chokes and a rift continuation to a final choke, mostly rocks and gravel. Paris Passage is straight and almost certainly joint controlled.
Continuing down at the second waterfall, the stream flows through a narrow crawl before entering Black Arrow Inlet, following the line of a strongly pronounced joint. The entrance to the passage is guarded by a 5m wade, (the Chert Canal), and then continues as an uncomfortable cherty crawl for 80m, ending at the foot of a shingle slope (the Sliding Scale). A further slope and crawl turns a right angle corner to the right into a high, spacious rift (Old Man's Rift). Past a boulder blockage and an unstable boulder collapse on the left (with a possible dig beneath), the rift ends after 30m in a crawl and climb into Frog Chamber, the entrance chamber of Pollprughlisk (entered over the border in the Republic of Ireland in County Cavan). This part of the system has a double shaft entrance with a total depth of 60m that leads to over 350m of mostly tight, joint controlled passages, with a small chamber continuing to a final boulder strewn chamber.