(S (S (S (ADVP (RB So) (RB far)) (COMMA ,) (S (BASENP (DT the) (NN dig)) (VP (VBZ has) (VP (VBN revealed) (NP (NP (QP (ADVP (IN at) (JJS least)) (NN 8)) (NNS houses)) (NP (QP (RB roughly) (NN 14-16)) (BASENP (NNS feet) (NN square)))))))) (CONJP (COMMA ,) (CC but)) (S (BASENP (NNS scientists)) (VP (VBP say) (SBAR (IN that) (S (BASENP (PRP they)) (VP (VBP think) (SBAR (S (NP (EX there)) (VP (MD may) (VP (VB have) (VP (VP (VBN been) (BASENP (QP (ADVP (IN at) (JJS least)) (NN 25)))) (ADVP (RB altogether))))))))))))) (PERIOD .))