Homeowner said any excavation for the new place keeps uncovering more glass. These were a couple pieces from job clean up, nobody wants rusty nails/metal or glass to be stepped on including me.
There are a lot of 'surface dumps' where a load of trash was just dumped on the ground in an out of the way place. If you can probe the area you can probably find if there was a pit of some sort. In some areas trash was burned in one location and the ashes and other residue hauled away periodically. If that is the case, there isn't much hope. You can tell because items will show burn or scorch marks. Your shards look like the right age, now just get that probe and find a pit (or privvy). Good Luck!!
i think any location which is turning up a lot of broken glass is worth some further exploration to determine why and what time period its from . but if it will produce anything worth while is tough to say