The Upper Jurassic Morrison Formation has yielded an abundant flora of the so-called ""transitional conifers"". Recently, a silicified axis of one of these conifers, which may be araucarian and having only an occasional indistinct growth ring, was collected from the Salt Wash Member in essentially the same horiwn and adjacent to a partially preserved Stegosaurus skeleton. The axis was collected from fluvial sediments indicating that the log was transported and then deposited. Two other axes of conifers were also collected at the same locality. Paleoecological considerations have been extrapolated from the coniferous flora, vertebrate fauna and associated lithologies. Thus, suggested paleoclimatic conditions of these conifers and associated reptilian fossils will be discussed.