( ( When ( ( the glaciers ) melted ) ) ( , ( they ( ( left ( behind ( deposits ( composed ( of ( ( a ( complex mixture ) ) ( of ( ( ( coarse and ) fine ) ( grained ( unconsolidated sediments ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (NNS glaciers)) (VP (VBD melted)))) (, ,) (NP (PRP they)) (VP (VBD left) (PP (IN behind) (NP (NP (NNS deposits)) (VP (VBN composed) (PP (IN of) (NP (NP (DT a) (JJ complex) (NN mixture)) (PP (IN of) (NP (ADJP (JJ coarse) (CC and) (JJ fine)) (JJ grained) (JJ unconsolidated) (NNS sediments))))))))) (. .)))
When the glaciers melted, they left behind deposits composed of a complex mixture of coarse and fine grained unconsolidated sediments.
(ROOT (S (NP (NNS Glaciers)) (VP (VB deposit) (NP (PRP$ their) (NN sediment)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VB melt))))) (. .)))