From 1907 Census.
Daniel William Hollis: Present Post office address: Vernon, Alabama; born 16 Sep 1840 in Tallahassee, Miss; first entered service as private in 1863 at Tuscumbia, Ala in Loyd's Co Roddy's Cav and continued until disbanded at Fayette C.H., Ala in May 1865.

I wasn't really sure which regiment Loyd's Co belonged to but now thanks to some helpful post it appears to be the 5th.

This is all the info that I have on Daniel besides a census or two. The Derrill that you mentioned was his brother. My information shows that Derrill was born in 1836. Also I have Derrill on page 595 of the 1860 Marion Co Census. Derrill was listed with His wife Jane Guyton Hollis and brother in law Nathaniel Guyton (26/32 MS INF.).

Michael