the big cross of mounds was thick stones .
(ROOT_0 (S_0 (ATS_3 (NP_1 (NP_6 (ATNP_1 (DT_0 the) (JJ_1 big)) (NN_1 cross)) (PP_0 (IN_1 of) (NP_4 (NNS_1 mounds)))) (VP_4 (VBD_1 was) (NP_2 (JJ_1 thick) (NNS_1 stones)))) (DOT_0 .)))