The National Park Service site lists a 42nd Regiment, Arkansas Infantry. I have assumed that like the other 40 series regiments, this one was a unit raised in 1864 for Price's Misouri Expedition and was thus a "Mounted" Infantry Regiment, but I have been unable to find information on this unit. It list the following members:

1
Burns, A.J. F Private Private
2
Cary, Francis C Private Private
3
Howe, William O. D Private Private
4
Phillips, P.J. B Private Private

Any idea's on the commander of this unit?