Fossil woods were collected from the Upper Cretaceous to Paleocene beds distributed around Heilongjang (Amur) River area of China and Russia.A total of 43 specimens were collected from Baishantou,Longgushan,and Yong 'ancun in Jiayin,China,and 85 specimens from Zeya-Bureya Basin lying southeast of Blagoveshchensk in Russia.Selected specimens were sectioned and studied anatomically.The source deposits of almost all identifiable specimens belong to the Upper Cretaceous (Campanian) Taipinglinchang Formation and the Paleocene Wuyun Formation in China,and the Paleocene Upper Tsagayan Formation in Russia.Although the results obtained are still far from complete,the taxonomic composition of the fossil woods show marked stratigraphic differences between the two horizons beyond the K/T boundary in China.There is also a strong similarity in wood flora between the Wuyun Formation of China and the Upper Tsagayan Formation of Russia.All identified specimens from the Taipinglinchang Formation are Xenoxylon latiporosum.This is one of the stratigraphically younger records of Xenoxylon,which is a conifer morphogenus of uncertain affinity most common in the Triassic to Early Cretaceous.Only one specimen with possible derivation from either the Wuyun or the Maastrichtian Furao Formation in China was identified as Taxodioxylon sp.The Wuyun Formation yielded both conifers and dicotyledonous woods.The conifers include Taxodioxylon sequoianum of the Taxodiaceae,and Protopiceoxylon amurense,which is attributable to the extant genera Keteleeria or Nothotsuga of the Pinaceae,both are at present endemic to China.At least two morphotypes of dicotyledonous woods were recognized,with one identified as cf.Hamamelidoxylon,and the other diffuse porous wood is characterized by numerous heterogeneous rays.From the Zeya-Buleya Basin of Russia,Taxodioxylon sequoianum and cf.Hamamelidoxylon sp.were identified from the Upper Tsagayan Formation.The similarity of wood composition in both Wuyun and Upper Tsagayan Formations support lithological as well as biostratigraphic correlations proposed for the two formations.