(S (S (BASENP (NN Radiocarbon) (NN dating)) (VP (VBZ indicates) (SBAR (IN that) (S (BASENP (DT the) (JJ original) (NN bluestone) (NN circle)) (VP (VBD was) (VP (VBN built) (PP (IN around) (BASENP (NN 2300) (NN BC))))))))) (PERIOD .))