The Descendants of John Allison of Washington County, Pennsylvania by James R Allison
"During the Wevolutionary War, Gavin served in the Washington County Pennsylvania Militia. He served as a private in the 4th Company, 3rd Battalion. He lived in Cecil Township at the time. The area later became part of St. Clair Township, Allegheny County, Pennsylvania. In 1834, Gavin and Mary moved to Mercer County, Pennsylvania.
Many variations of Gavin Allison`s first name have been recorded in the public records and remembered by his descenants. These spellings include Gaius, Gian, Gaines, Gauyn, etc. However, they all refer to the same person."