I have not been able to connect the Isaac MARTIN of Burke, NC so cannot say for sure but it does appear that this line was English and married into Cherokee. Many of the Cherokee were as much white as Cherokee, many having European surnames, and many did not leave during the Removal of 1818, making it impossible to locate them in any of the Indian rolls. It is possible to "lose" an ancestor because of this and the fact that Native Americans were not counted in the Census at that time.