I think it's from the early Paleo-Sebenzoid Era.
Lol. Yes... I bet the action is very smooth. It predates the ATS-34 period a little; CPM-FLNT?
Jill is our local river-stalker. A beautiful collection, and there are even a couple of pieces that show similarity of shape to the one found by the OP.
Thanks, Jill.
Yeah, it looks close to the one in the center. Maybe for skinning, scraping bone? I didn't really see much of a pattern until the fourth photo, showing the edge. It's hard to tell. Oceans and rivers can create shapes in stone and minerals that look manufactured... the salt deposits left on the shore of the Dead Sea, in almost perfect crystalline cubes. The fewer the trace elemental impurities, the more exactly they mimic their tightly-packed molecular matrix at the macro scale -- there actually
are straight lines in nature, relative to what's detectable by the human eye. There's video around, of tourists collecting them, like ice-cubes, but glassier. But those do look like tool marks.
These all were found on the Ohio River, within 10 miles of me.
It's strange they're not particularly valuable -- at least not in North America, since they don't date back that far, 16 000 years, max, and most much earlier (the arrow-heads might only be a few hundred years old). If a Paleolithic tool turns up that radio-carbon-dating places earlier than
that, it would support claims of artifacts dating as far back as 50 000 years B.P. -- another matter entirely. I was also surprised when I first learned that actual Mammoth Ivory was being used on knives -- it seemed to me they should be prohibitively expensive or of great value scientifically... but seeing the sheer tonnage found in places like Siberia, it's not as rare as I assumed.
