Complex sentence: Of his 4 children, Arthur P. Morton and Pierce Edward Morton I am uncertain as to what happened-except that Pierce Edward Morton was living with his uncle Edward Morton in East Gwilbury Canada when the 1861 Census was taken.
Split into simpler sentences: Of his 4 children, I am uncertain as to what happened to his son Arthur P. Morton. His other son, Pierce Edward Morton was living with his uncle Edward Morton in East Gwilbury Canada when the 1861 Census was taken.