Fossil flora of the Paleocene Ravenscrag Formation, southwestern Saskatchewan, Canada

The Paleocene Ravenscrag Formation of southwestern Saskatchewan, Canada, is a lignite-bearing clay, silt, and sand unit which, in places, bears abundant, well preserved plant fossils. These sediments conformably overlie Maastrichtian dinosaur-bearing deposits and are interpreted as including the earliest Paleocene. Examination of the fossil materials at the Ravenscrag Butte study site indicate that the depositional environment was that of a broad alluvial plain dominated by meandering streams, ponds, swamps, and lowland forests. The paleoclimate was mesothermal, humid, and without a dry season. Rain was abundant and frost, if it occurred, was rare. A mean annual temperature of about 150C and mean annual range in temperature of 230C are proposed for the region giving an effective temperature of 140C and an equability of M 49. Forty-five distinct fossil plant species are identified and described from these sediments, with an additional 20 types of fossil remains described. The study of these fossil plants indicates that during earliest Paleocene time this region of southwestern Saskatchewan was covered with the lush vegetation of a mainly broadleaf deciduous local flora