The fact that he served in the French - Indian Wars is confirmed by an entry for him in the book "Westchester County New York and the French and Indian Wars. 1755 - 1762." by Fredrick O. Haacker. 1952.

The entry for John Slawson states that he enlisted on March 31st of 1756, he gave his age as 22, and stated he was born in Stamford. His trade is listed as labourer. The muster roll also states that he was 5 ft 7 inches tall, and served with Captain Reuben Lockwood.

Jonathan is also mentioned in "History of Stamford Connecticut", written by Rev. E.B. Huntington. In a chapter entitled "The period of the French and Indian Wars", Huntington states the following: "Jonathan, Sylvanus and Deliverance, sons of Deliverance and Hannah ‎(Hoyt)‎
Slason, of whom Jonathan was in the Navy of the war. Neither of the sons ever returned."

The implication of Huntington's statement is that all three were killed in the French and Indian War. The evidence cited in the Slawson book seems to contradict Huntington's statement. Both Jonathan and Deliverance seem to have been alive many years after the war.

The will of Jonathan's father, Deliverance states the following:

"Item. To Jonathan Slason, the son and heir to my oldest son Jonathan, who is supposed to be dead, I give and bequeath five pounds New York tender, to be paid within a year after my decease."

The use of the word "supposed" is very odd. It obviously implies some doubt as to the status of his son, when he wrote his will in April of 1775. I imagine that this statement in his fathers will, is the source for the statement in the Slawson book the Jonathan died before 1775.

Two items that could still be investigated. Is there a burial record for Jonathan Slason in Hortonville, Vermont, around 1775. Secondly, can Huntington's implication that Jonathan served in the Navy during the French and Indian Wars be verified.