The Nehemiah Manross who was born in 1722 could not possibly be the father of Samuel, also born in 1722. I have obtained quite a bit of circumstantial evidence that Samuel's father was Nehemiah Manross (sometimes given as Montrose or Monroe), born in 1690. This Nehemiah was married to Esther Bishop and the father of her seven children. Esther died in 1742 so he may have married Thankful Cooper for his second wife.
All the children and descendants of his line have used the Manross spelling as their surname.
All the children and descendants of his line have used the Manross spelling as their surname.