There is the following in Land Grants & Petitions:

John Cameron, the younger son of John Cameron a U.E.L. of Lot 16, 4th of Cornwall 9th July 1802. (This is the 4th and not the 5th Concession)

John Cameron Land Grant No. 872 Roxboro son of Daniel Cameron of Lot W 6, 1st Concession Roxboro. Lot 20, 9th Fitzroy. This is Daniel and not Donald but see next listing.

Charles and William Cameron Land Grants 3636 and 3637 son of Donald Cameron sometimes called Daniel, of S.S.M.B.R.R. Cornwall, a U.E. Loyalist, Roxborough.

On the lot next door to your Donald Cameron of Lot 16 Concession 5 Cornwall is:

Margery MacPhail Petition # 163 (3rd Section) Reel: C-2184 Cornwall – 5th Lot 15 December 28, 1842 wife of the late Archibald MacPhail, Twp of Cornwall, daughter of Donald Fraser of lot 15, SSMBRR 5th Cornwall a UE Loyalist, deceased who died upwards of ?? years ago and was then aged about 80. Rec. 200 acres…Donald Fraser a deceased late soldier in 84th Regiment.

There is no more information about Margaret Fraser Cameron than what I gave you.