( ( Some ( are ( in ( ( lowlands , ) ( some ( on sideslopes ) ) ) ) ) ) ( , ( some ( ( ( are ( in ( ( mountains , ) some ) ) ) ( by oceans ) ) . ) ) ) )
(ROOT (S (S (NP (DT Some)) (VP (VBP are) (PP (IN in) (NP (NP (NNS lowlands)) (, ,) (NP (NP (DT some)) (PP (IN on) (NP (NNS sideslopes)))))))) (, ,) (NP (DT some)) (VP (VBP are) (PP (IN in) (NP (NP (NNS mountains)) (, ,) (NP (DT some)))) (PP (IN by) (NP (NNS oceans)))) (. .)))
Some are in lowlands, some on sideslopes, some are in mountains, some by oceans.
(ROOT (S (NP (NNS Scientists)) (VP (VBP know) (SBAR (IN that) (S (NP (DT some) (NNS mountains)) (VP (VBD were) (ADVP (RB once)) (PP (IN at) (NP (NP (DT the) (NN bottom)) (PP (IN of) (NP (DT an) (NN ocean))))) (SBAR (IN because) (S (NP (JJ marine) (NNS fossils)) (VP (VBP have) (VP (VBN been) (VP (VBN found) (PP (IN on) (NP (NP (DT the) (NNS peaks)) (PP (IN of) (NP (DT some) (NNS mountains)))))))))))))) (. .)))