My best guess is a pill bottle. Liver pills, asprin, heart pills.
I have a "hoods pills - dose to cure liver ills, GI Hood and co lowell Mass"
about 1" tall, and 1/2" thick. I dug it in a spot where it had been dug all to heck. This is so small, it was overlooked. Kovels lists it at 55 dollars I think. You can fit it in your watch pocket.