I think he may have been Egbert Benson Hull.The info on his stone is 12 Jul 1864, died Petersburg.Buried in Center Berlin Cemetery.
If you go to findagrave.com and plug in the surname Hull, New York, Rensselaer County, you will find him there & a pic of the stone.The wife on his stone is Abigail S Thomas tho.....
Also look at Hezekiah Hull Jr in same cemetery.He was Egbert's father & the mother was Sarah Gray.Her parents, Daniel Gray and Sarah Harris are buried there too.There are pictures of stones and family info for everyone.Also there are Hezekiah Sr, father of Hezekiah Jr & wife Lucy Randall.
Daniel Hull, father of Hezekiah Hull Sr & wife Mary Betts are buried in Hull Cemetery - there are links to parents & children and more family info.
So the line appears to be - Egbert, Hezekiah, Hezekiah, Daniel, Ebenezer, Cornelius, (from whom I descend), Cornelius and then the immigrant George b 1590 Crewkerne England & Thamzen Mitchell.
The Hulls of Fairfield & Redding CT seem to be rather well-documented.I saw mine in many church records looking at films from LDS.Also try the CT Genweb.
As far as Mary goes - perhaps she was Abigail Mary or Mary Abigail or even a first wife, or perhaps it is a mistake?I have some duplicate pictures that have the names of people that copies were meant to be sent to - perhaps it is something like that....
Here's census for Egbert - hoping maybe some of the names might present a pattern....
1850 Berlin, Rensselaer, NY
Egbert Hull34NY Abigail S36 Lydia V(Virginia)11 Cethora/Seflora/Sefloria1 Laura L6
Notice the gap between Lydia & Laura - room for a first wife?
Egbert B Hull 43 Abigail S45 Sfloria18 Florence L (Laura?)16 Lydia V21 Winfield Gray7 - perhaps related to Sarah Gray ?
New York Town Clerk's Registers of Men Who Served in the Civil War ca 1861-1865:
Egbert Benson Hull Birth1818 birthplaceBerlin father - Hezekiah Hull mother - Sarah Gray ResidenceTroy, NY Enlisted 26 Dec 1862 Enl locationBerlin, Rensselaer, NY Regiment - 125th Infantry Rank1st Lt Racewhite marital statusmarried