I believe there are three spellings of the name: Jernegan, who settled in Martha's Vineyard, MA, Thomas Jarnagin (Above) of Tennessee, and the Jernigans, who settled in North Carolina. William Jarnagin did indeed do a chart of the Jarnagin family. I have the original of this and am not sure if there are any copies left. However, I might be able to help with specific questions if the answers are on the chart.