Gottesfeld, A. S.; Swanson, F. J.; Johnson Gottesfeld, L. M. 1981. A Pleistocene low-elevation subalpine forest in the western Cascades, Oregon. Northwest Science. 55(3): 157-167.
A boulder diamicton exposed in the low Lookout Creek valley, western Cascades, Oregon, containsfossil wood, needle, and pollen material representative of a Pleistocene flora > 35,500 radiocarbonyears in age. The deposit was probably formed by a debris torrent from a tributary watershed. Someof the wood fragments are abraded and randomly oriented, suggesting transport from upslope areas.Abies sp., Pseudotsuga menziesii, and Thuja plicata are represented in these wood specimens. Othermaterials, including unabraded wood, needles, and pollen occur in a continuous, horizontal layerthat may represent a small piece of locally formed forest floor litter. This valley bottom flora con-tained abundant Picea cf. englemannii and Abies cf. lasiocarpa. These fossils suggest the occurrenceof Picea englemannii/ Abies lasiocarpa forest in a cold valley bottom with more xeric forest com-munities on adjacent hillslopes.
Present arboreal vegetation at the site is dominated by Tsuga heterophylla, Thuja plicata, andPseudotsuga menziesii. Modern examples of the community represented by the fossil assemblageoccur at elevations over 1000 m higher than the Lookout Creek site. The Lookout Creek assemblageprobably represents a flora of an early Wisconsin or previous glaciation under conditions signifi-candy drier than those prevailing during late Wisconsin glaciation.