Sentence:  The Mesozoic rock units in the Békés-Doboz trough appear to correlate to similar age rock units of the Bihor <WSD>autochthon</WSD> in the Apuseni Mountains of Romania rather than to rock units of the Codru nappe system. Rock units of the Bihor <WSD>autochthon</WSD> differ from rock units of the Codru nappe system in 3 main aspects: ... 
Meaning of the word marked with <WSD> tags:  A large mass of rock in the place of its original formation, rooted to its (id=geology) (foundation rock) as opposed to an allochthon or nappe which has shifted from the place of formation; an autochthonous rock formation.