Abstract: In the regional stratigraphic classification and correlation, the Lower Tertiary strata are absent in Guyang basin, Inner Mongolia. A suite of patchy-colour detrital rock system is identified in the Early Cretaceous Lisangou Formation determined by our predecessors. The present research into the stratigraphic features, sedimentary sequence, paleontologic assemblage, diagenesis and tectonic pattern of the said strata shows that this suite of strata overlying unconformably the Early Cretaceous Lisangou Formation is characterized by loose cementation, poor diagenesis, simple tectonic style (dominated by the fault-block movement) and Angiosperm-herb pollen assemblage. Furthermore, the distinctive differences are present between this suite of strata and the Early Cretaceous Lisangou Formation in terms of biological assembly, diagenesis and tectonic pattern. The analysis of the biologic assemblage of this suite of strata indicate the formation age of the strata at the Early Tertiary.