That picture is upside down. That is a 1st regiment light artillery button. It has a script "LA" for light artillery and below is the regiment number. Amazing find! And it's in beautiful shape.
I hunt in northeast MA, and at this site in particular I've found:
2 William III Half Pennies (1694, 1696)
1 George II REX Half Penny (1732)
An awesome trade weight with the cyphers: w/m Royal, St Paul dagger, London House, another I'm not sure (looks like an "A")
Multiple of buttons
Multiple buckles
Three-ring roundball
very simple bracelet (chained metal rings, simple designs)
Various bits of metal, ie: spoon pieces, tool handles
1928 Standing liberty (nearby, not in cellar hole)