Recent field observations indicate that no dinosaur remains are known to occur above the Nevis coal seam. Therefore, previous conclusions which placed the Cretaceous–Tertiary boundary at the base of the Ardley coal seam are modified. A microfloral change recorded at the top of the Nevis seam in south-central Alberta corresponds to similar palynofloral changes at the Maestrichtian–Paleocene boundary in the northwestern interior of the United States. This microfloral change is considered synchronous in the region stretching from Alberta to Colorado and coincides with the dinosaurian extinction at the Maestrichtian–Paleocene boundary. In the light of this new evidence, it is proposed that the Cretaceous–Paleocene boundary be placed at the top of the Nevis coal seam in Alberta.