Iron Patch is correct, your button shows the US Marines emblem, not Navy. But there is no EXACT match-up for your button in the Albert button-book or the Tice button-book. So, you've either found a previously-unknown variety, or your 1-piece button is a modern-era civilian clothing "Fashion" button.
Unfortunately, your photos of it are somewhat blurry. At the moment (until you can post several well-focused photos of both sides of it) I lean toward it being a modern-era "Fashion" button, for three reasons:
1- You indicate that you dug it, but it has no oxidation/patina (on either its front or back), which a long-buried brass button should show.
2- It has no backmark, but instead appears to be completely blank/plain, not even a circle on it. ALL of the 1-piece Marines buttons in the Albert and Tice books have some kind of backmark. Repro and "Fashion" 1-piece buttons typically lack a backmark.
3- No exact match-up for its emblem in the Tice and Albert button-books.
Please make and post several well-focused photos of your button's front and back, so we can figure out the mystery conclusively. If it turns out to be a previously-unknown 1820s/30s US Marines button, Warren Tice definitely will want to see it.