Anthony,
You ask: "I am wondering if he means they served in Hogg's command and Van Dorn later rather than when they were in NE AR in 1861/62?"
Based on the information below, it appears that Locke's regiment was unassigned to any brigade [but under Van Dorn's orders] until the order of April 9, 1862, as Van Dorn was crossing his army to Memphis. As you know, there was a substantial reorganization of the army about this time, and also after the army arrived at Corinth.
I have attempted to extract pertinent information regarding the 10th Texas Cavalry from my notes on the Army of the West. Hope this will be of some help, although most of it will be obvious to you.
1. A search of the Texas message board for Locke reveals such postings as these [extracts]
http://history-sites.com/mb/cw/txcwmb/index.cgi?index
Posted By: Jerry CoffeeDate: Tuesday, 28 February 2006, at 3:23 p.m.
.......In 1861 Locke was elected State senator but declined the office due to his military obligations. Col.M.F.Locke conveyed property SE of Pittsburg,Texas to his son, Lafayette, and raised the 10th Texas Cavalry in Upshur and the surrounding counties. The town of Lafayette, Texas was established on the M.F. Locke land patent. The 10th Texas Cavalry consisted of 900 recruits and underwent four months of training at Camp Tally near Coffeeville, Texas. My great, great, great grandfather, Samuel Wyatt, had a State of Texas land grant just north of Pittsburg Texas (now in Camp County) and was close friends with Matthew Locke and his family.
In December 1861, the 10th Texas Cavalry moved out of Camp Tally with marching orders to join Gen. Ben McCulloch in Missouri. My great, great grandfather Elijah D. Wyatt went with the regiment as a sutler of harness and leather goods.Unfortunately the 10th Texas Cavalry never obtained suitable cavalry mounts. A measles and typhoid fever epidemic took the lives of about 200 men of the 10th Texas Dismounted Cavalry during the march to Little Rock and after they arrived at Camp Henry E. McCulloch. My great, great grandfather was one who died of measles and is one of 428 Confederates who are buried in unmarked graves in the Confederate Cemetery, at Camp Nelson east of Cabot, Arkansas. In 1862, Gen. Allison Nelson also died of camp (typhoid) fever. After Gen. Nelson's death, Camp McCulloch was changed to Camp Nelson in his honor........
Posted By: Jerry Coffee Mon, 5 December 2005, at 2:12 p.m.
My great, great grandfather Elijah D. Wyatt was a sutler with the 10th Texas Cavalry. He operated a tannery in Coffeeville and provide harness and leather goods to the recruits at Camp Tally. Col. M.F. Locke was placed in command of the 10th Texas Cavalry (dismounted) and it was raised in Upshur,Smith, Rusk and Cherokee Counties with new recruits from Camp Tally at Coffeeville in Upshur County.
In December 1861, my great great grandfather loaded several wagons with harness and leather goods and was marched to Little Rock Arkansas with the 10th Texas Cavalry. The regiment was marched to Clarksville Texas and by the spring of 1862 the regiment was in Little Rock Arkansas. Many of the troops of the 10th Texas Cavalry suffered from a measles epidemic and exposure during the long march. My great, great grandfather died of measles in early 1862 and is buried in the Confederate Cemetery in Little Rock.
The suvivors of the epidemic were sent east of the Mississippi River and were combined with Ector's Brigade and saw their first action at Richmond Kentucky then at Murphresboro,Tennessee. They remained with Ector's Brigade for the remaineder of the warand saw action at Vicksburg and other locations in Mississippi. At the end of the war, only about 200 of the original 1000 recruits of the 10th Texas Cavalry returned to their homes. That created a severe economic hardship in the area and on the families in particular. Many families left the region for the new settlements in central and west Texas.
Posted By: Jerry Coffee Sunday, 5 June 2005, at 10:59 a.m.
....My great, great grandfather, Elijah D. Wyatt, had a tannery at Coffeeville in Upshur County Texas. He made harness and leather goods and supplied the Confederate troops training at Camp Talley which was located at Coffeeville, Texas. In 1861, Locke's and Earp's 10th Texas Cavalry Regiment was raised in Smith, Upshur and Cherokee County and was in training at Camp Talley. In 1861, the 10th Texas Cavalry (dismounted) had 900 effectuals.
The 10th Texas Cavalry (dismounted) was moved from Camp Talley to Clarksville and was marched to Little Rock Arkansas. My great great grandfather Elijah Wyatt was 42 years old and was too old to enlist when the 10th Texas moved out. He loaded several wagons with harness and leather goods and accompanied the regiment to Arkansas as a sutler. A measles epidemic took 150 men on the march to Little Rock and upon arriving at Little Rock, the 10th Texas was marched to Fort Smith and a few days later, was ordered back to Little Rock. My great, great grandfather died of measles in 1861 and is buried in the Confederate Cemetery in Little Rock.
Weakened by poor rations and the long road marches, by the time the 10th Texas arrived back in Little Rock, the regiment had lost 350 men to disease and exposure....
Posted By: Jerry Coffee Mon,12 December 2005, at 10:59 a.m.
During the winter of 1861-1862, Col. M.F. Locke's 10th Texas Cavalry (dismounted) had about 30% casulties in Arkansas from a measles epidemic and exposure during the winter road march from Camp Tally in NE Upshur County Texas to Little Rock. When the 10th Texas arrived in Little Rock, they were marched to Fort Smith then immediately returned to Little Rock and sent across the Mississippi River to join Ector's Brigade in Tennessee. No doubt the unnecessary road march after they arrived in Little Rock, the lack of provisions and exposure caused additional casualties..........
2. Official Records [Extracts]
EXECUTIVE DEPARTMENT, Austin, Tex., October 22, 1861. General P.O. HEBERT: SIR: Your communication of the 16th instant was duly received. I am gratified that you have ordered Colonel Parsons, with his regiment, south. He was anxious to obtain service in Texas. One object of my writing at this time is to procure, if possible, the acceptance of Colonel Locke's regiment. From information just received I fear that he has taken up the line of march in the direction of the coast. If so, it has been done without orders from me, and I presume in consequence of advices given him by Colonel Parsons. Though the duty of the soldier is to await and obey orders, I am disposed to excuse his non-observance of this obligation, for the reason that they have promptly responded to my call for their services and are exceedingly anxious for service. This regiment would have gone to Missouri without hesitation, but are now of the opinion that Texas may need them; and, if so, they prefer to stay at home. I am aware that you do not desire a very large cavalry force, not more perhaps than you now have. It may occur, however, that you may need additional cavalry troops; and, indeed, I see through the papers that you are in some instances authorizing the raising of cavalry companies. Would it not suit your views to receive this regiment now, in expectancy of future contingencies? Might it not be well employed at Brownsville until the forces desired for that post be obtained? We have an extended seaboard, and, if invaded in that quarter, I should think a considerable cavalry force would be needed. It is now very late, too, to send men to Missouri; and, for this reason and the probable necessity that comes upon us for our volunteers at home, I would be greatly gratified if you would accept this regiment, and request, if consistent with your opinions of duty and propriety, that you do so. In addition to the impracticability of their now going to Missouri, I will state that they have been some time organized, and equipped themselves at considerable expense. Many of them have abandoned their employment to engage in their country's service, and, if disappointed or disbanded, the consequences would be ruinous to them. Colonel Young's regiment, as also that of Colonel Sims, I feel satisfied, from advices received, have been started to Missouri. While I do not wish to embarrass you, and by no means to control your operations, I sincerely desire and request that you have this regiment immediately put to service in Texas, if you can. . . .....EDWARD CLARK.
JACKSONPORT, March 15, 1862. General VAN DORN: The enemy under General Steele is advancing on Pocahontas with a force variously estimated from 5,000 to 12,000. I shall send all the troops I have here to re-enforce Colonel McCarver.......General Rust telegraphed me to send all the Arkansas troops that were armed to Clarksville. I could not do it. I have but four companies here, and Locke's regiment, who were taken with the measles at the rate of thirty a day. The steamers are all so high that his regiment would be of no service up there. I shall keep them here.... W. L. CABELL.
3. Army of the West orders:[abbreviated transcriptions]
April 9, 1862 Des Arc S O #45--Hogg is assigned to the brigade now under Greer, to which Locke's Tex cavalry regiment is added. Hogg is to proceed to Memphis for organization of his brigade.
4/13 During the transfer of the army from Arkansas to Mississippi, Van Dorn, on April 13, 1862, ordered units including Col Locke's 10th Texas cavalry to report to Gen Price at Memphis [after dismounting], and as soon as it could cross the Miss. River.
4/15 Des Arc-Locke's Tx cav reg't-after dismounting per S O #4[3?] to Memphis and report to Price.The order for Col Locke to remain as post cdr of Des Arc is hereby revoked
4/18 Memphis S O # 55-Until the organization into brigades-Gen Hogg is asgd to the camp of troops that are not incl in Price's Division
4/21Memphis S O # 59-Following is organization of 1st brigade/2nd div Army of the West
Hogg [dismounted cavalry]
Young reg't
Locke reg't
Greer reg't
Crump bn
Goode btry
4/29 On April 29th, Van Dorn published orders in Memphis announcing the organization of the Army of the West. The organization of this particular date included the new brigade to be commanded by Gen Hogg. This brigade [on that particular date] included McCray's Ark battalion [later became the 31st Ark infantry regiment], the 10th and 11th Texas Dismounted cavalry regiments, and Crump's [battalion] Texas cavalry [later the 15th aka 32nd Texas Cavalry]. There were several revisions to this organization in the weeks and months ahead.
5/16 Hogg died on May 16, and was replaced by Cabell in brigade command.
6/13 S O # 113-Col Locke of 10th Tx cav is discharged
6/30 By the June 30, 1862, table of organization, the 14th Texas dismounted cavalry regiment was also included in Cabell’s brigade along with the 10th Texas Dismounted Cavalry. Of course, after this date, the 10th and 14th Texas were assigned to Ector’s brigade and detached from the Army of the West for the Perryville campaign, and Cabell was given an Arkansas brigade for the battle of Corinth.
Other sources include:
4. web site for the 10th Texas Cavalry
http://gen.1starnet.com/civilwar/10cvmain.htm
5. Bio of Colonel [General]Hogg
http://www.tsha.utexas.edu/handbook/online/articles/HH/fho18.html
6. Supplement to the Official Records