The Digital Library on American Slavery holds a lot of information about Native as well as mixed people. http://library.uncg.edu/slavery/index.aspx
In the petition below, presented to the North Carolina General Assembly, and subsequently rejected, we catch a glimpse of the remnants of Chowan Indians in 1790.
PAR Number 11279002
State: North Carolina Year: 1790
Location: Gates Location Type: County
Abstract: William Lewis and Samuel Harrell ask that a law be passed validating the title to a tract of land acquired by a group of people descended from American Indians and blacks. They state that in 1724 the Chowan Indians received 11,360 acres of land from “the true and absolute Lords proprietors of North Carolina” lying in Chowan County, now Gates County. Noting that “the whole of the Said Chowan Indian Men is dead,” they point out that that left “a parcel of Indian Women, which has mixed with Negroes, and now there is Several freemen and Women of Mixed blood as aforesaid which have descended from the Sd. Indians, who consider themselves “intitled to the Small Remnants of the aforesaid Tract of Land that was not sold nor conveyed by the aforesaid Indians in their Lifetime.” Lewis and Harrell state that the said freemen “have for a valuable Consideration Conveyed the Said Remnants of Land to your Petitioners,” whereby they pray that a law may be passed “authorizing the said free men of mixed blood as aforesaid to sell and make titles” to the said land and that said titles “shall be good and valid in Law.” Supporters of Lewis and Harrell aver that “the freemen aluded to in the petition Did in the late Contest with Great Brittain behave themselves as good and faithful soldiers in behalf of this and the United States.”