Much appreciated, George. (I own M258, six rolls, including 120, but had not gotten into M269 r70.) Routh's service is, indeed, interesting and difficult for an "East Coast researcher" working remotely. Among the complications, he was b. in Natchez, MS, but identified with "the family plantation" in Tensas, LA across the river, splitting queries between two message boards. He was a "junior," requiring a separation of on-line data. He was not the only Stephen M. Routh of his time (one in MO association has to be separated, for example). Among "pre-war" refs found on-line, I had been trying to settle identification with Bondurant's company, 15th Bn (Harrison's) LA Cav and the Tensas Cavalry of 1860, wherein he is identified as having been "employed" 17 Mar 1861 (i.e., prior to CMSR info) "to drill cavalry troops." (What was source of his military knowledge, I wonder? His father, who d. 1858, had been a cadet at Norwich, but no info on son's mil experience.)

At this point, I am reasoning that he may have had some involvement with the local (Tensas, LA) post-John Brown vol militia (cav) preparedness, yet, when the time came to sign up, he went in with a cavalry unit from his birthplace in Natchez, MS.