anybody know what this W H JONES button is about?

[luckyeddee]

found this detecting. the button eye is gone. on the back it says w h Jones extra. on the front is a picture of a cannon, eagle and cannon balls with the word "corps" printed on the bottom. any help appreciated.

 

[CreakyDigger]

It looks like a Militia Artillery button, 1814-1821. Link here.