Upper Cretaceous continental red beds in West B¾c Bé in particular, and in Southeast Asia in general, were formed in a hot and arid climatic regime, yielding evaporites, but containing a few fossils, causing difficulty in the sediment dating. During the first field work season of the project "Geological mapping and mineral resource survey of the Yªn Ch©u sheet group at 1:500,000 scale", for the first time fauna and flora fossils have been found in red beds at Yªn Ch©u, allowing to date the host rocks as Late Cretaceous.