George Martin
Hack (Harry) Vandiver enlisted as a Private in Company I, 18th (Newsom's) Cavalry May 1, 1864 at Jackson, paroled at Brownsville, Tennessee May 31,1865
This regiment was consolidated about March 1865 with the 20th (Russell's) Regiment Tennessee Cavalry and the consolidated regiment was paroled at Gainesville, Alabama, in May, 1865, as the 19th and 20th Regiment Tennessee Cavalry.
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Company C, 19(20)th Tennessee Cavalry, resident of Madison County, Tennessee recorded on a list of absentees and deserters from the 19th and 20th Tennessee Cavalry Regiments at Verona, Mississippi dated February 28, 1865
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Consolidation
In late January of 1865, Forrest reorganized his command. Many of the units raised in late 1863 had experienced significant losses from action and disenchantment. One report suggests that Company I was down to well under a dozen men:
Everybody in low spirits about the War. All talking about going home and quitting the War for it is a failure. (Chester (1988))
The shrunken units made consolidation necessary.
Initially, companies were combined within the regiment. By the end of February 1865, Company E of Russell's regiment combined men from the earlier Companies C, H, and I. Company G may also have been included at this time. A "new" Company K was assembled from the Henry County companies -- E, F, and K. Companies A, B, and D remained as separate units.
Later, apparently in early March, consolidation of regiments took place. An attempt was made to group units along geographical lines, and all of the Tennessee troops were placed in a single division reporting to General W.H. Jackson (Official Records, I-49-1, p. 933).
Russell's 20th regiment was consolidated with Newsom's 19th regiment to form the 19/20th Consolidated Cavalry Regiment. Smaller bands of men were also incorporated into the consolidated unit -- notably the 1864 command raised by A.T. Gay (into Co. E, 19th/20th) -- as were Tennesseeans from Faulkner's 12th Kentucky regiment (into Co. G, 19th/20th) and Ballentine's 2nd Mississippi Partisan Rangers.
http://home.olemiss.edu/~cmprice/cavalry/history.html#consolidation
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18th (NEWSOM'S) TENNESSEE
CAVALRY REGIMENT
Usually called 19th Tennessee Cavalry Regiment
Organized May 11, 1864; consolidated March, 1865 with 20th (Russell's) Regiment; paroled at Gainesville, Alabama May, 1865 as the 19th and 20th Tennessee Cavalry Regiment.
http://www.tngenweb.org/civilwar/csacav/csa18cav.html