1. Geological Museum of Jilin University, Changchun 130026, China;
2. Research Center of Palaeontology & Stratigraphy, Jilin University, Changchun 130026, China;
3. Key Laboratory of Paleontology and Stratigraphy of the Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

In this paper, fossil spores and pollen from the Lower Cretaceous Longjiang Formation in the Pi? geon Hill fossil locality, Daur Autonomous Banner of Morin Dawa, Hulun Buir, Inner Mongolia, are systematically reported. Forty?nine genera and seventy species were identified. Gymnosperm pollen is dominant, among which un? differentiated bisaccate “ancient” pollen is the main component, while pollen of Taxaceae, Pinaceae, Podocarpace? ae and Cycadales accounts for a certain percentage. Spores of pteridophytes take the second place. They are mainly of Cyatheaceae, followed by spores of Lycopodiaceae, Lygodiaceae and Selaginellaceae. Angiosperm pollen occurs in small quantities. According to the composition characteristics, the present assemblage is named as Cyathidites ??Taxodiaceaepollenites ??Tricolpopollenites. Based on the index taxa, the geological age indicated by this palynological assemblage is assigned to Aptian??Albian. The ecological habits of the mother plants in the present palynoflora indi? cated that the Early Cretaceous climate in the Pigeon Hill area was warm and humid, possibly accompanied by sea? sonal drought.