A search of Memphis National Cemetery revealed this.

Adkins, William H, d. 08/03/1863, PVT B 10 IOWA INF, Orig Bur Memphis Tn, Plot: A 2193, *

Note however the asterisk.

* Records with an asterisk at the end indicates those that have not been verified by the U.S. Department of Veterans' Affairs. Please visit "The National Cemetery Administration Records Verification Project " for details on what this means.