Scattered deposits of Tertiary fossil (petrified) woods are to be found throughout most of the Western Cascades adjoining the eastern side of Oregon's Willamette Valley, but those deposits making up the area known as the Sweet Home Petrified Forest in Linn County are among the most abundant and well known.That article makes for some interesting reading. In particular, the list of identified taxa is pretty amazing, in terms of diversity and the climates they indicate. The photo above is of the narrower but much taller stump at the Sweet Home Community Museum. The two pieces displayed there are outside, so you can stop and see them, even if the museum is closed. As Gregory comments in the article, the quality of preservation is remarkable. In thin section, it's essentially identical to modern, unfossilized, wood slices of the same type.
The abundance of the area's fossil wood is evident even to the casual traveler. It may be seen crushed or as fill in driveways, in fences and retaining walls, and in decorative garden work. Larger pieces -- stumps and logs -- mark driveway entrances and hold up mailboxes; barn floors have been built of it and abandoned wells filled with it. Farm people of an earlier day considered it a great nuisance -- a feeling perhaps carried over, justifiably, by today's landowners at times harried by avid rock hunters.
Photo unmodified. March 9, 2012. FlashEarth location.