underground [Adjective] + cavern [Noun]

Strength Strength Dispersion
A:
14
CHISQ:
3,289.8
AWT:
8,296,841
TTEST:
3.73
G2:
137.01
FAWT:
6.55
MI:
7.89
LOGLOG:
30.03
JD:
0.71
MI3:
15.5
DICE:
2.1
RANGE: