Here is a post from the Texas boad that relates to transfers from Texas regiments to Stirman's battalion:

http://history-sites.com/mb/cw/txcwmb/index.cgi?read=3661

Additionally, Whitfield's Texas Legion was formed with 13 companies in April of 62, including Catterson's Arkansas company. This company wound up in Stirman's battalion, and perhaps some of the other excess companies of this Legion did as well. See

“Ross Texas Brigade” by Victor Rose

Whitfield Legion was organized on 4.2.62 by the addition of 9 new companies to Whitfield battalion
and now had 11 cos from Texas and 2 from Ark. .... short time after the reorgianization [5/8] when the Ark Co B Capt. W. Catterson transferred to an Arkansas command.

Order # 105 dtd June 4, 1862
Capt. Catterson’s company of Arkansas cavalry transferred from Whitfield’s Texas Legion to Brooks Battalion of Arkansas Cavalry

And---

Order #98 dated May 25
for the continued transfer of companies from Williamson's Ark Bn. 1 co to McCray Ark Battalion, and the balance [those not already assigned to other units] to Brooks Battalion