Len, I found them on "The Civil War in Virginia" website under "Military Units in Virginia". It says: see Louisiana 12th Artillery Battalion, Company D, Captain Balfour's Company. I've done some searching on The 12th LA but haven't found mention of The Bethel Heavy or why they would have been detached to a Louisiana Battalion. The 12th Louisiana was instrumental in the defense of Port Hudson. I'll keep digging.