Twenty-four samples were collected and processed for palynomorphs from the type section of the Mattson Formation at Jackfish Gap, Northwest Territories. One hundred and fourteen palynomorph species were identified including seven new ones. The new species are Auroraspora hybo, Corbulispora trana, Crassispora bipartita, Densosporites asperus, Mooreisporites manus, Raistrickia multipusa and Secarisporites scaurusa. Four of the samples were found to be Early Cretaceous in age and are included in the Buckinghorse Formation. These samples indicate that a previously unmapped basal Cretaceous sandstone is present at Jackfish Gap. Two spore zones, the Densospore zone and Convolutispora zone, are described. Within the Densospore zone Rotaspora fracta, Densosporites asperus n. sp., and Converrucosisporites armatus can be used to establish subzones. On the basis of environmental interpretations, the section can be divided into a lower marine zone, a middle nonmarine zone, and an upper marine zone. Several lines of evidence are used in interpreting environments including the presence of scolecodonts, fossiliferous dolomites, relative abundance of spores, Densospore/Lycospora ratio, and number of species present.