It is theorized that the key to this can be found with this gentleman.  

Christoph Reifenbergers Homepage - www.reifi.de

Homepage von Christoph Reifenberger - reifi.de

The page is in Deutsch, not English, so be forewarned.  The good news is that Google can translate the page for you.  Once there you can select the TREE at the TOP of the page and begin to explore.  From here you will discover Oberreifenberg of Schmitten and the paradox of where they went to is being investigated presently.  If you are interested in confirmed Royal Knights of this area you can Google Cuno/Kuno von Reifenberg and Walther von Reifenberg the only known Knights of Riefenberg.  

It is very well documented in the papers of Christoph von Graffenried, 1st Baron of Bernberg, also known as Christoph de Graffenried himself a Swiss Palatine gathering settlers from the poor German and disenfrachied Swiss and others sought settlement of several thousand Swiss Palatines, German Lutherans and Palatines including many Bernese settlers. 

Christoph was a Swiss, British Peer authorized to settle new lands in Carolina.  Christoph is credited with funding, transporting and then founding the new English Colony at New Bern in the Province of Carolina in 1710.  The colony was formed at the confluence of the Trent River and the Neuse River and was home to the Tuscarora an Iroquoian People.

After severe hardships in their own countries, the group, now going were willing to try starting over again, this time in Carolina. He sailed with the colonists to Carolina in 1710. On the sea voyage the settlers were attacked by French privateers who stripped them of everything they brought with them. Whereas, on a similar voyage of nearly 3000 German Palatines departing London for New Amsterdam where nearly decimated with one-third be laid to rest during the sea voyage, or shortly thereafter as they arrived to New Amsterdam and were Led by John Lawson.  John Lawson is most famous in North Carolina.  He lived from 1674c – 1711.  He was an English explorer, naturalist and writer. He played an important role in exploring the interior of colonial North Carolina, South Carolina and Georgia, publicizing his expeditions in various books. He founded two settlements in North Carolina: Bath and New Bern, both at the coast.

During the settler’s first season, their crops did not perform well. Von Graffenried quickly returned to Europe to obtain supplies and additional settlers. He returned to the colony unscathed. In addition to a lack of food and supplies, there was great tension between the settlers and the Tuscarora Indians of the Neuse River region. The Tuscarora are an Iroquoian-speaking people, closely related to the Five Tribes of the Iroquois Confederacy based in central and western New Amsterdam. The settlers had unwittingly planned their new settlement on the site of an old Tuscarora village.

In 1711, von Graffenried and the settlers evicted a group of Tuscarora from nearby lands without payment, and von Graffenried had now assumed the title "Landgrave of Carolina." Retaliatory raids by the Tuscarora, under a leader named Hancock, led to many casualties for the new settlers.  

During the summer of 1711, von Graffenried, John Lawson and an unidentified African slave handling their baggage ventured up the Neuse River in hopes that they would be able to locate a suitable native grape to hybridize with his native European ones.  It was not long that the  Tuscarora took captive; von Graffenried, John Lawson, and an enslaved African whom they had entrusted with their baggage. While in captivity, John Lawson and von Graffenried were given three separate trials, each held at different Tuscaroran villages. In one trial the men were found not guilty.  The two remaining trials produced unanimous judgements as guilty of crimes against the Tuscarora. The verdict of The Tuscarora was then passed and they both were sentenced them to Ritual death.  However, upon much discussion spanning several weeks, the leaders decided von Graffenried would be released. The notation is that he wore such fine clothes they had mistook him for the Governor of Carolina. In this instance, believing Graffenried was the Governor, they pardoned him and his slave.

It is also stated that the chief told them of their impending attack being mounting against all the settlements of the Virginians that were in their lands.  The following day, the  Tuscarora Priests began their ritual torture of John Lawson.  Von Graffenried was released only with the promise and condition that no new European settlements should be made in this region without first obtaining sanction by the native chiefs who lived upon and cared for these lands.  When he finally reached New Bern, he found it totally abandoned and in flames.

Unbenounced to Graffenried, a group of almost 500 were escaping up the Trent River into what today is Jones County, North Carolina.  At the head of the Trent, the Northeast Cape Fear River is only a few miles away and flows to the Cape Fear and down to Wilmington.  This is evidenced within a Map created by Edward Moseley in 1733, we see his indication of a Palatine Settlement near to Rockfish and the Little Rockfish Stream and Creek.  I believe that these are the lost descendants of all Rivenbark lines worldwide.  

In my experience, this is exactly the timeframe where the old German spelling of the surname was lost and perhaps it did come from Riefenberg when they said it in German to the Irish and Scottish Gaels that were already present and knew of good lands suitable for farming and for little fear of the native inhabitants that were scarce there.