Pollen diagrams made from the sub-surface Late Quaternary sediments of Upper Assam, India, reveal palaeoecological and vegetational patterns which include associations of a large number of temperate ferns and other subtropical/temperate plants. A peat sample at a depth of 1.80 m dates back to 17,930 +/- 575 yr BP. The occurrence of north-east Asian elements like Carya, Pterocarya, and Tsuga suggests a trans-migratory link between India and countries of north-east Asia during the time of deposition which has been subsequently eliminated due to climatic change or some other natural phenomenon.