or ers ▁had ▁passed ▁the ▁newly ▁named ▁George ' s ▁Ch oke . ▁The ▁end ▁of ▁the ▁cave ▁was ▁reached , ▁ ▁down stream , ▁at ▁the ▁terminal ▁sum p ▁( sum p ▁ 3 ) ▁beneath ▁another ▁large ▁b ould er ▁cho ke , ▁and ▁the ▁extension ▁to ▁this ▁point ▁was ▁named ▁" The ▁May fly ▁Ext ension ". ▁ ▁While ▁discover ies ▁were ▁being ▁made ▁in ▁Sh annon ▁C ave ▁in ▁ 1 9 8 0 , ▁attention ▁was ▁also ▁being ▁paid ▁to ▁a ▁large ▁dol ine ▁less ▁than ▁a ▁kilomet re ▁away ▁in ▁County ▁F erman agh . ▁M embers ▁of ▁the ▁Rey f ad ▁Group ▁( including ▁the ▁a for ement ioned ▁Rev . ▁Pitt ) ▁and ▁the ▁Irish ▁C aving ▁Club ▁worked ▁together ▁to ▁dig ▁their ▁way ▁into ▁passage ▁leading ▁to ▁a ▁ ▁under ground ▁sh aft , ▁with ▁b ould er ▁ch okes ▁and ▁craw ls ▁at ▁its ▁base . ▁They ▁named ▁this ▁cave ▁Co - operation ▁Pot ▁in ▁honour ▁of ▁their ▁collaboration , ▁but ▁later ▁the ▁name ▁Pol lt ul ly ard , ▁after ▁the ▁local ▁town land , ▁was ▁adopted . ▁▁ 1 9 9 0 s – 2 0 0 0 s : ▁Pol lah une ▁collapse ▁and ▁new ▁entrance ▁ ▁The ▁Pol lah une ▁entrance ▁to ▁Sh annon ▁was ▁always ▁dangerous , ▁often ▁dump ing ▁rocks ▁on ▁passing ▁ca vers ▁and ▁finally ▁in ▁ 1 9 9 5 ▁it ▁col lapsed , ▁making ▁the ▁cave ▁in access ible . ▁During ▁subsequent ▁years ▁attention