The traditional naming pattern was followed often enough, to make it a reliable clue for finding or confirming other data. But remember that if the first son or daughter died at an early age, on the frontier, there may not be a record of the birth or death, and an apparent inconsistency when none really existed. I did some research recently on Quaker naming patterns -- some of my Virginia ancestors appear to have been Puritans (normally associated with New England) who later became Quakers. The Puritans, of course, seemed to have used the dictionary for names -- Original, Temperance, Cotton, for examples. The Quakers, who sometimes made it a community project, put great importance on name selection and had reasons for their choices other than family heritage. I think the use of surnames, as first names, may have had Quaker origins, but I'm not sure that there is any conclusive evidence to that. Incidentally, in the Middle Ages (circa 1100) the law of primogeniture applied to surnames. Only the eldest son could keep the family surname; all of the other children would have to find their own. If the eldest son died without issue, the name would go to his younger brother, etc. That is why there are so many English surnames based on places ("locative" names), occupations, and other descriptive methods.