Two buttons.

One button has a rope twist edge. Within a raised circular border on a lined background is a pre-1901 crown with a fouled anchor below it. The rope is attached to the ring at the top, then goes under the right-hand side of the stock, under the shank to the left, then back under the shank to the right and disappears under the right arm. Officer's button between 1843 - 1891.

One button has a smooth edge. On a smooth background is a pre-1901 crown above a fouled anchor. The rope is tied to the ring at the top, then goes under the left-hand side of the stock, under the shank to the right, then under the shank to the left, before going under the left-hand shank to curl under the crown and under the right arm. Possibly a warrant officer 1812 - 1860.