Thank you for your reply.
Alex Rose's land petition says that he came to Canada in 1780(Que/Ont?) and has been in Glengarry since 1784. He was stationed at the "Cascades" in 1781 with a detachment of Sir John Johnston's Regiment Royal Yorkers under Captain Law and in 1782 the detachment was sent to Lake Champlain as marines under command of Ensign Smith. He was on the Maria Sloop of War.

Alex also says he emmigrated from Scotland in 1773 to Bermuda. In 1774 he went to Virginia and in 1775 to New York.