Cool find. I found the top of one in a school soccer field that used to be an apple orchard. There is a BIG signal that I haven't dug out there just because of the size of the hole I'll have to dig but I'm thinking it might be the rest of the flask.
One of these days I'm gonna dig it. The field has been very nice to me with childrens' silver rings.
Thanks for sharing and GOOD LUCK, ALL.