I have been working with a local land conservancy, the Cherokee Ranch, to help them develop a research and education program for archaeology. They already have a geology program started, and the geologists invited me to go on a field visit to look at petrified wood on the ranch property a few days ago.
They have a lot of it on the ranch and you can see a couple of logs in these pictures. I asked to go along for two reasons: One, I think petrified wood is cool, and Two, petrified wood was a major source of tool stone for the prehistoric people in this area. I figure mapping the extent of this stuff is helping define prehistoric quarry sites for me.
I learned a couple of things on the hike. These deposits date to the Paleocene (56-66 million years ago) and apparently petrified wood from the period is rare in North America. Also, the oval cross-section of the logs is due to the fact they were deformed by pressure from the weight of deposits above them before they were mineralized. The geologists are bringing out an expect on petrified wood from North Carolina this summer to identify the tree species. They are currently guessing laurel for most of it, but want confirmation.
You need to look closely at this last log for important detail.
This log was one of the quarry sites I was looking for. The white egg-looking object is a quartz hammerstone that is surrounded by a scatter of flakes. Looks like someone sat on the end of the log and started making tools. Two hundred years ago, five hundred years ago, a thousand years ago?