I believe it to be an old fashion button, Jeff, called Waterbury anchor style 29444, or anchor with rope edge. http://www.waterburybutton.com/cart/pc/viewPrd.asp?idcategory=0&idproduct=27996 I have seen it posted here before. Yours is a nice old example. I believe this backmark was used from 1849-1965. WATERBURY BUTTON CO. *