ABSTRACT
The former group is very ancient appearing 450 million years ago as plants first began colonizing land during the Devonian Period. Seedless plants include liverworts, mosses, horsetails, and ferns. Conifers constitute the biggest group of gymnosperms, and modern conifer forests are dominant over large areas of landscape, as in much of modern Alaska. The Cretaceous rocks of Alaska contain an abundance of extraordinary fossil floras, and the overwhelming majority of these floras are dominated by fossil plants with seeds. The Nanushuk flora is composed of ferns, ginkgos and their relatives, cycads and their relatives, conifers, and angiosperms. The thickest exposures of non-marine sections of the Nanushuk Formation are in the western part of northern Alaska. The Prince Creek Formation is a Late Cretaceous to Paleocene non-marine to marine sedimentary unit in northern Alaska. The original stratigraphic work on this rock unit had extended it into the in the form of the Tuluvak Tongue of the Prince Creek Formation.
