The input of plant matter of allochthonous origin contributes energy, nutrients, and substrates in a variety of important ways.
-- Thomas F. Waters, "Dynamics in Stream Ecology," Production of Juvenile Atlantic Salmon, Salmo Salar, in Natural Waters, 1993
However, coals which have formed from plant remains which have been transported considerable distances from their original growth site are known as allochthonous coals, e.g. large rafts of peat or trees drifting on lakes or estuaries.
-- Larry Thomas, Coal Geology, 2002
Allochthonous entered English in the late 19th century. It was modeled as an antonym to autochthonous, meaning "indigenous."