"Histories of the Several Regiments and Battalions from NC in the Great War 1861-'65" is available on line at http://behind.aotw.org/2010/01/04/a-hypertoc-for-histories-of-the-several-regiments-and-battalions/

Also, John T. Mebane has 17 records in his CSR file under 68th North Carolina & Clark's Special Battalion. These is available to order through this message board, from the National Archives, subscription to Footnote.com, or perhaps at some North Carolina libraries.

Good luck with your search.