Thanks Tentis. You may be correct, but it seems old, and was down fairly deep located in a old area. I was thinking jeans or work cloths. What come to my mind are Levi, Lee, Wrangler. I'm not sure of other older brands.
Congrats on your finds. It does look like a snap button, but maybe you did not know that Levi Strauss was granted the patent for blue jeans in 1873. I do now know when the snap buttons may have started to appear.
Even though snaps were invented in the 1860's and patented in 1885, and didn't become popular until just after 1900, so the snap is modern to many.
On the west coast of NA your find would be "Old" in England your find would be termed "Modern" given the history in both examples.
You stated "My gut says it's old but I just don't know. I did ID the rifle bullet casing as a Remington arms 1917 so I know the area is old." Though it's 100yrs old it only represents 1/4 of our modern history basically.
Regardless of terminology they are recovered pieces of history, so well done.