A comparative analysis of Late Jurassic-Early Cretaceous strata have been done for the SanjiangMiddle Amur basin, a coal-and oil-bearing area spanning the eastern Heilongjiang of northeastern China and southeastern Far East of Russia. On the basis of various fossils occurring in the formations, particularly by means of the Tithonian-Valanginian indexBuchia and the late Barremian-middle Albian indicator Aucellina assemblages, the marine and non-marine Late Jurassic-Early Cretaceous strata in the basin are correlated. The Mesozoic international chronostratigraphic chart (http://www.stratigraphy.org) is established basically based on the marine rocks. To accurately date the non-marine strata, it is necessary to correlate them with the marine deposits. This study sheds new light on the dating and correlation of non-marine Upper Mesozoic. Additionally, the results would help understand the tectonics and paleogeography and thus aid the exploration of energy resources. Upper Jurassic-Lower Cretaceous, marine and non-marine, correlation, Sangjiang-Middle Amur basinThe Sanjiang (Heilong (Amur) River, Songhua (Sungari) River, Wusuli (Ussuri) River; Jiang means river in Chinese)-Middle Amur (Heilong) sedimentary basin situated on the northwestern coast of Paleo-Pacific during the Late Mesozoic presently spans the boundary of Russia-China. Its southwestern part is situated in eastern Heilongjiang, northeastern China and the northeastern part in southeastern Far East of Russia (Figure 1). This basin contains Late Mesozoic marine and alternating marine and non-marine deposits, commonly associated with volcanic rocks, and yielding abundant coal and even oil [1][2][3][4][5][6][7][8][9][10] . In the basin there exist the Jurassic-Cretaceous boundary [9,[11][12][13] and the mixed boreal and Tethyan fauna recording the paleocurrent events [14][15][16][17] , recordings of the transgressions along the Tan (Tancheng)-Lu (Lujiang) fault system [10,18] .Consequently, Sangjiang-Middle Amur basin is a unique area for the study of the Late Mesozoic paleontology, stratigraphy, paleogeography, tectonics, and energy resources. Although much has been published on paleontology, sedimentology, stratigraphy, paleogeography (including the transgression and paleocurrents), and tectonics of the basin, most of them are concentrated on either the Chinese part or the Russian part without correlations between them. Four UNES-COIUGS IGCP Projects (350, 434, 506, 507) and a joint Russian-Chinese project [1,18] made it possible to examine the boundary structure and the evolution of the basin. Even though the Jurassic-Cretaceous boundary of the basin was globally discussed [11] , the correlation between