adjective
also al·loc·tho·nous -_thənəs
Etymology: all- + -chthonous (as in autochthonous )
1.
a. : of or relating to the rocks of an allochthon
b. of coal : formed elsewhere than in situ and hence not autochthonous
c. of limestone : composed largely of organic debris moved far from the place where the base organisms lived
2. biology : of foreign origin : introduced — compare autochthonous