(S (S (BASENP (PRP It)) (VP (VP (VBZ is) (VP (VBN believed))) (SBAR (IN that) (S (NP (BASENP (QP (RB about) (NN 80))) (PP (IN of) (BASENP (DT such) (NN bluestone) (NNS blocks)))) (VP (VBD were) (VP (VP (VBN transported) (PP (IN from) (NP (BASENP (DT the) (NNP Preseli) (NNPS Hills)) (PP (IN in) (BASENP (NNP Pembrokeshire) (COMMA ,) (NNP Wales)))))) (PP (TO to) (BASENP (DT the) (NNP Salisbury) (NNS plains))))))))) (PERIOD .))