▁in ▁ 1 9 8 7 ▁and ▁now ▁displays ▁ 3 ▁white ▁flash es ▁separated ▁by ▁ 2 . 5 ▁seconds ▁and ▁repeated ▁every ▁ 2 0 ▁seconds . ▁The ▁light ▁is ▁ 1 8 2 , 0 0 0 ▁cand le power ▁and ▁on ▁a ▁clear ▁night ▁can ▁be ▁seen ▁for ▁approximately ▁ 4 2   km . ▁ ▁The ▁buildings ▁within ▁the ▁grounds ▁of ▁the ▁l ighth ouse ▁are ▁now ▁priv ately ▁owned . ▁C ars ▁are ▁not ▁allowed ▁along ▁the ▁road ▁leading ▁from ▁Fer ry den ▁to ▁the ▁l ighth ouse ▁but ▁it ▁is ▁a ▁popular ▁walk ▁and ▁sight ings ▁of ▁se als ▁and ▁dol ph ins ▁are ▁not ▁unusual . ▁Wh ales ▁are ▁sometimes ▁seen ▁in ▁the ▁area ▁including ▁rare ▁sight ings ▁of ▁hum p back ▁wh ales . ▁ ▁Ge ology ▁Sc ur die ▁N ess ▁is ▁a ▁Ge ological ▁Conserv ation ▁Review ▁( GC R ) ▁site . ▁The ▁Old ▁Red ▁Sand stone , ▁la vas ▁and ▁associated ▁sed iment ary ▁rocks ▁found ▁there ▁are ▁part ▁of ▁the ▁Mont rose ▁Vol can ic ▁Form ation . ▁These ▁rocks ▁were ▁formed ▁around ▁ 4 1 0 ▁million ▁years ▁ago ▁from ▁la va ▁being ▁er upt ed ▁from ▁a ▁vol cano ▁lying ▁to ▁the ▁north - east ▁in ▁the ▁North ▁Sea ▁and ▁known ▁as ▁the ▁Mont rose ▁vol can ic ▁centre . ▁Sc ur die ▁N ess ▁is ▁ren owned ▁for ▁its ▁ag ates ▁formed ▁by ▁flu ids ▁flow ing ▁through ▁the ▁la va ▁and ▁depos iting ▁sil ica