I found at Ancestry that Shubael was a Civil War veteran. If you want to get into it more deeply there seem to be pension files, one filed in 1889 claiming invalid status and one in 1894 claiming Mary J as widow. Note that the index at least at Ancestry has Mary J as Mary F, but this is because the person indexing did not notice that part of the stroke making the cursive J was hard to see and called it F.
This is what Ancestry has for his service.
I don't know if Footnote.com has this sort of record online yet or if you'd have to go to the National Archives films.
Shubael Norton ,
Residence: Tisbury, Massachusetts
Enlistment Date: 28 Aug 1863
Side Served: Union
State Served: Massachusetts
Service Record: Enlisted in Company B, 34d Infantry Regiment Massachusetts.
Enlisted as a Sergeant on 28 August 1863 at the age of 23.
Enlisted in Company F, 3rd Heavy Artillery Regiment Massachusetts on 16 Sep 1863.
Mustered Out Company F, 3rd Heavy Artillery Regiment Massachusetts on 18 Sep 1865 at Washington, DC.