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Abstract Cercidiphylloxylon spenceri(Brett) Pearson is described from the Lizigou Formation, Palaeocene in China. The growth rings are distinct; pores are diffuse, solitary, with somewhat angular outlines in cross section; vessel elements long with long scalariform perforation plates; intervessel pitting is opposite to scalariform; fiber-tracheids are present; axial parenchyma is scarce; rays are mostly biseriate and heterogeneous. All wood characters of the fossil specimen fall into the range of those of extant Cercidiphyllum(Cercidiphyllaceae). The finding is one of the earliest fossil wood records of Cercidiphyllaceae.

A sedimentary rock complex overlays the deep layers of oceanic crust in the Mussau Trench (and the conjugated underwater ridge) of the Caroline Basin. Paleontological analyses supported the previous idea of Oligocene-Quaternary deposits. In addition, Upper Cretaceous (Acila ex gr. demessa, Anisomyon sp., and others) and Eocene (Heterostegina sp., Discocyclina sp., and others) deposits have been found, suggesting shallow water environments in Late Cretaceous-Early Cenozoic time. Later on, regional submergence started. The complex of the deep-seated formations of the Mussau Trench is not younger than the Early Cretaceous oceanic crust of the Ontong-Java Plateau.