Two natural rock formations are always pointed out on excursions.
( ( Two ( natural ( rock formations ) ) ) ( ( ( are always ) ( ( pointed out ) ( on excursions ) ) ) . ) )
(ROOT (S (NP (CD Two) (JJ natural) (NN rock) (NNS formations)) (VP (VBP are) (ADVP (RB always)) (VP (VBN pointed) (PRT (RP out)) (PP (IN on) (NP (NNS excursions))))) (. .)))
Natural rock formations on visible on excursions.
( ( Natural rock ) ( ( ( formations ( on visible ) ) ( on excursions ) ) . ) )
(ROOT (S (NP (JJ Natural) (NN rock)) (VP (VBZ formations) (PP (IN on) (ADJP (JJ visible))) (PP (IN on) (NP (NNS excursions)))) (. .)))