Hey, good job digging this up, Collin!
Not very many folks interested in this stuff but this chapter comes from the 2006 report,
"Stone Quarries and Sourcing in the Carolina Slate Belt", and is the most
recent and definitive published research done yet on the "lithic" rocks of the slate belt.
This was a combined effort of archaeologist, geoarchaeologist, and geologist from around the state.
The main goal of the project was to collect samples of rock from known prehistoric quarry sites in the slate belt
and do extensive visual and chemical analysis on the specimens to see if a "singular" trait or signature
could be found to identify one source of rock from another.
One of the big questions for archaeologist is, "where did the lithic material come from?", and this project
was to try and get some answers to that integral question. That is what the word "Sourcing" refers to in the title of the report.
And if you Google the title above you can now find all 195 pages of the report online.
I was very happy and honored to take part in this project.
They ended up using 3 of the 5 quarry sites I showed them, 1 in Chatham Co., 1 in Durham Co., and 1 in Person Co.
Despite my pleas not to, they named one of the Chatham County quarries after me in the report.
You can see it listed on the graph there in Chapter 3, page 19.
Let me know if you have any questions about this report.
The professionals were really hoping to find a key identifying signature with the chemical analysis,
chiefly Neodymium and Samarium Isotope ratios. I have always been in favor of a physical/visual identification database.
The chemical analysis was not unique enough to tell one source in a cluster area from another close source,
but there were some notable differences between "areas" further apart.
The 70'some thin sections and petrography done on the specimens, in my opinion, was work that really needed to be done.