For some reason your book won't allow me in.
I'm very familiar with the Murray Springs Site having Black Mat samples, a marvelous Clovis hammer stone rescued from a flash flood & some crumbs that are all that remain when mammoth bone is exposed to the environment.
IIRC Vance finally came out against the BM theory and I had read his thoughts on the subject some time ago. BTW the Murray Springs dig was finally written up, ~40 yrs after work was completed.
The dating on your beach mat is ~10Kyr too young, but I have read that finds have been made in Northern Europe, possibly England? One of the easy ways to eliminate false finds is a strong magnet - the BM contains magnetic particles. Enclosing the magnet in a condom will allow the particles to be removed easily.
Not aware if you have any ice age bones lying about in your region, but if the black mat is there, it will drape them, but never be found under them.
That is one beautiful beach - I'm envious!
We used the strata as a marker to know when we were close to ice age or Clovis goodies decades before anyone had any idea of what it was it why it was there.
Goodyear and Firestone are still the authorities when it comes to the BM, although a very well thought of anthropologist at ROM (Royal Ontario Museum) in Toronto has told me that after finding magnetic particles embedded the upper portions of most of the Mammoth and Mastodon tusks in their collection, he's become a true believer.
He gave a wonderful lecture a few years back for the OAS (Ontario Archaeologist Society) with samples, tusks and a magnet, ever brought a ball thrower for his dog as an example of a modern atlatl
- I provided some samples from further afield.
[size=78%] [/size]Terry
BTW If I'm drifting into the pedantic please, gently, make me aware of it.