. ▁It ▁is ▁also ▁called ▁Sl ieve ▁Russell ▁or ▁Lig ave gra ▁( Also ▁Leg av ag ra , ▁Lig av ag ra ). ▁It ▁has ▁an ▁elev ation ▁of ▁ 4 0 4 ▁metres ▁above ▁sea - level . ▁OS ▁ 1 / 5 0 k ▁Maps heet : ▁ 2 7 A ▁& ▁ 2 6 . ▁Grid ▁Ref : ▁H 2 3 4 ▁ 2 2 6 . ▁ ▁The ▁mountain ▁is ▁made ▁up ▁of ▁grey ▁lim estone ▁with ▁a ▁cap ▁of ▁sand stone ▁and ▁sh ales ▁and ▁is ▁extens ively ▁quar ried ▁by ▁local ▁companies . ▁The ▁surface ▁is ▁mostly ▁covered ▁with ▁pe at , ▁p ine ▁for ests ▁and ▁gra zing ▁fields . ▁The ▁mountain ▁contains ▁several ▁c aves ▁and ▁sw allow - hol es ▁including ▁Pol ln ag oll um ▁( Sl ieve ▁R ush en ) ▁and ▁T ory ▁H ole ▁which ▁are ▁a ▁popular ▁destination ▁for ▁p oth ol ers , ▁both ▁situ ate ▁in ▁Leg av re ag ra ▁town land . ▁It ▁forms ▁part ▁of ▁the ▁Sl ieve ▁R ush en ▁Bog ▁Natural ▁Heritage ▁Area ▁. ▁A ▁recent ▁addition ▁to ▁the ▁mountain ▁is ▁the ▁Sl ieve ▁R ush en ▁Wind ▁Farm ▁for ▁generating ▁electric ity . ▁ ▁Et ym ology ▁ ▁The ▁name ▁Sl ieve ▁R ush en ▁der ives ▁from ▁the ▁G ael ic ▁" S li ab h ▁Ros - in " ▁which ▁means ▁" The ▁Mountain ▁of ▁the ▁Little ▁Wood ". ▁However ▁an ▁alternative ▁explanation ▁of ▁the ▁name ▁is ▁given