An important early material, obsidian, was discovered on the island of Milos.
( ( ( ( ( An ( important ( early material ) ) ) , ) obsidian ) , ) ( ( was ( discovered ( on ( ( the island ) ( of Milos ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT An) (JJ important) (JJ early) (NN material)) (, ,) (NP (NN obsidian)) (, ,)) (VP (VBD was) (VP (VBN discovered) (PP (IN on) (NP (NP (DT the) (NN island)) (PP (IN of) (NP (NNP Milos))))))) (. .)))
They discovered obsidian on Milos and took it back with them.
( They ( ( ( ( ( discovered obsidian ) ( on Milos ) ) and ) ( ( ( took it ) back ) ( with them ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VP (VBD discovered) (NP (NN obsidian)) (PP (IN on) (NP (NNP Milos)))) (CC and) (VP (VBD took) (NP (PRP it)) (PRT (RP back)) (PP (IN with) (NP (PRP them))))) (. .)))