New information, and the help of Alan Pitts, has convinced me that Dr. Sampson Noland Ferguson was actually the Captain of Company C of the 5th Alabama Infantry and Company I of the 7th Alabama Cavalry.

There is still the possibility that Sydenham "Sidney" H. Ferguson was involved with the recruitment of another cavalry company. I believe, though, that it is more likely that this, too, was Sampson Noland Ferguson.