1) There is a death of a George Fulton, born 1840, in the Marine Register for 1879. Looks like he met the usual seaman's death
2) Otherwise, there is also a George Fulton, born 1843, who died in Dennistoun, Glasgow City in 1876. Since the age is off a bit on this one, and your George was a sailor, I would tend to go for the Marine Register death.
You have a lot of new information to digest here-- good luck!
All the best,
Sarah