Examining a piece of broken glass

 I was back at the Edwin S. Wilder Wildlife Management area in Raynham, in the same spot where I previously found a piece of deliberately flaked glass (see here) and found another bit of old broken glass that caught my attention. Thick, dark green, edged (deliberately?), and scratched on its front and back surface. Let's take a look:

These things have a sort of beauty. 

Note the two edges on either side of the tip. This one...

...looks like it was pressure flaked. 

And this one...

...looks like it was battered or damaged. 

Looking at the surface, one notices directional scratches. The curious thing is that the scratches on one surface are more or less perpendicular to the scratches on the opposite surface. 

Note the scratches are perpendicular to the axis running up to the tip. Turning the piece over:

These scratches are roughly aligned with the axis up through the tip, perpendicular to the ones on the opposite side. So, if used, both sides were used.

Update: This indicates that prehistoric technologies remained in use long after you would expect. The same could be said about rock piles. Finding little sharp blades makes one kind of sense: you might need a scalpel. But a scraper? That indicates continued hide preparation activities. I am wondering what kind of trapping or souvenir industries would have that need?