James Graham Goodenough was a British Royal Naval officer who was Commander-In Chief, Australia Station. He died in August 1875 on board his ship, HMS Pearl, off the coast of Australia after being fatally wounded in an attack by natives of the Santa Cruz Islands.(Solomon Islands). Your medal appears to be one that was awarded as a Gunnery Memorial Prize possibly for competition between junior officers in the Royal Navy.It looks to be in excellent condition. Sorry, can't help with the value.