The following Roberts were in the 6th Texas Cavalry Regiment. Note your John C. Roberts was on an official roster of the 6th Texas Cavalry. Though I do not have any direct info on your Roberts, I do have a lot on the company and regiment. Peter Ross was the Company commander and another private in the company was Lawrence Sullivan Ross who was elected the Regimental commander in May 1862 andd went on to be the Governor and the President of Texas A&M.
Any direct descendent of a civil war soldier can become a member of the Daughters of the Confederacy or a Son of the Confederacy. These organizations promote the heritage of the South and rememberance of those who faught and died for their country. They are not radical and they do love our country. You can visit my web site below to learn more about the 6th. If you have any mor questions of the United Daughters you can contact me or go to their website at <http://www.hqudc.org/about/index.html>. If you ar interested in the SCV send me an e-mail or go to <http://www.scv.org/> the National web site.
There are several more Roberts in the Ross Texas Cavalry Brigade which included 4 regiments of north Texas.

ROBERTS NAPOLEON B. D ROBERTS, Napoleon B., Co. "D”, 1stSgt. 1st SGT
ROBERTS MARK R. D ROBERTS, Mark R., Co. "D” PVT
ROBERTS SAMUEL B. D ROBERTS, Samuel B., Co. "D” PVT
ROBERTS WILLIAM W. D ROBERTS, William W., Co. "D” PVT
ROBERTS JOHN C. G ROBERTS, John C., Co. "G” PVT
ROBINSON, Calvin, Co. "F” F ROBINSON, Calvin, Co. "F”
ROBERTS ABRAM M. H ROBERTS, Abram M., Co. "H” PVT