Samuel and Bathsheba Barrett Oxford had one chld, a son James, who remained in North Carolina, and left descendents there.
About fifteen years ago, a descendent of James, living in North Carolina, became interested in genealogy. He started a publication, soon subscribed to by a few genealogists, and otherwise subscribed to by a great many people just looking for names with which to fill in blanks on their genealogical charts. (This is what usually happens!)
In one of his last publications, this man said he'd tried to find Samuel Oxford Sr,'s parents by going through the few English records he could access. He was simply looking for a couple surnamed Oxford, who'd named a son Samuel within a limited time frame. He found several, and explained that he thought, of those he'd found, Thomas and Sarah Lulpeck Oxford, seemed the most likely. He specifically warned this wasn't proven though, and more research had to be done.
He wasted his breath! The name collectors grabbed the names, and rushed to the internet where, not citing their sources, or the fact it was unproven, announced to the other name collectors that Samuel Oxford Sr. was certainly the son of Thomas and Sarah Lulpeck Oxford. And the other name collectors, of course, couldn't wait to pass it on to still more people like themselves - those utterly unconcerned with making sure what they're accepting, and reporting, is fact.
I know of only one person who did what everyone should have done. He wrote to England, asking for more information on Samuel Oxford, son of Thomas and Sarah Lulpeck Oxford. He was told there was no more information on the son of Thomas and Sarah Lulpeck Oxford. Their son, Samuel, died in childhood. (No, I haven't personally verified this. There's no reason to. We don't know when Samuel Sr. was born, or where he was born either, and even if we did, we couldn't possibly identify his parents by trying to attach him to anyone surnamed Oxford who had a son named Samuel.)
The date and location of Samuel Jr's birth was discovered in the same way. The same man simply looked for a couple surnamed Oxford, who had a son named Samuel, born in Virginia within a certain time frame. He found only Samuel and Mary Oxford in Stafford County. He didn't look far enough though to learn Samuel and Mary Oxford weren't the only adult Oxfords there, or that there was an earlier Oxford settler in the county from which Stafford was formed. And he had no proof, or evidence, of where they were before they showed up in Stafford, or of where they went when they disappeared off record there. Except for the fact they shared the same surname, and he had the same given name as their son, there's nothing to connect them to Samuel Oxford Jr..
As for Samuel Sr. having married Mary Ann Brown, that comes from the same publication. It's based entirely on a legend exclusive to the descendents of James, and utterly unknown to descendents of Samuel and Bathsheba's many other children. For a time though, it looked promising. The Oxfords did know a member of a Brown family; one of the Oxfords bit his ear off in a fight, and there was a Mary Ann Oxford there too. Further research though has found no connection to the Browns, and evidence strongly suggesting Mary Ann is either the aunt, or sister-in-law, of Samuel Oxford Jr., not his mother.
As for Jonathan Barrett having married Jarfly Jarman, I won't even go into that. I'll just say the man who started the publication which, through little fault of his, resulted in all this nonsense being spread all over the net, did truely to believe the legend. He stopped the publication within about a year because he wasn't getting any new information. Most people subscribing weren't doing research, just looking for people who''d done it, or would do it, for them. (Yes, there were a couple of notable exceptions!) After stopping the publication, the man spent two years doing intensive and extensive work on the Catawba reservation. He finally concluded there was no such person as Jarfly Jarman, or Abel Barrett, and no evidence Jonathan Barrett had ever been involved with the Catawba in any way. He's since stopped doing research altogether, which is regretable.
You've now been warned. If you're reporting Samuel Oxford Sr. is the son of Thomas and Sarah Lulpeck Oxford, married Mary Ann Brown, and that his son, Samuel Oxford Jr., was born in Stafford County, Virginia, and married a daughter of Jarfly Jarmin Barrett, you're reporting as fact things which are not only unproven, but for which, after diligent research, not one bit of supportive evidence has ever been found. It's all just a combination of legends of unknown age and origin, shored up by supposition and conjecture. By all the rules of genealogical research, none of it can be recorded, or reported, as fact.
I'll close with a reminder there is wisdom behind the old adage - "Genealogy without documentation is mythology". If you don't document it yourself, don't accept it, and if you haven't proven it yourself, don't pass it on to anyone else. You owe it to your ancestors, to your decendents, and to yourself, to make sure what you're recording, and reporting, is true. The only way you can do that is to follow the cardinal rule of genealogy, and personally verify it from the source document itself. It takes time, and it isn't fun, but if you're not doing it, you're not doing genealogival research. If you're not doing it, what you're doing instead is like playing a game, trying to win a prize, but without any way of differentiating between the real prizes and the booby prizes. Needless to say, that's a good way of getting yourself stuck with a lot of booby prizes!