Thank you Bryan.
It appears the 3rd Ark Cav left Cornith after organization and went to Camp Armstrong, where Gen Van Doran left two divisions with Gen Price, in which 3rd Ark was in one, possibly in Bowen's Brigade. That being where the officers of the 3rd wrote their letter to Gen Price to be remonted, and on 28 Aug Special Order #72 was issued appointing Lt O C GRAY incharge of horses and recurits. Muster roll shows he was in Ark Sep 1st gathering horses, a forage bill from Little Rock is dated 14 Nov, and Forage bill at Camp Rogers states forage from 23 Nov to 11 Dec, 1852. So it appears; Lt O C GRAY went to Little Rock from Camp Armstrong, then to Princeton to gather horses, leaving Princeton 23 Nov arriving at Camp Rogers, Lumpkin's Mill, near Gernada, Miss the 11 Dec, and was promoted to captain the 13th while in Bowen's brigade according to dates and locations in his service record and his wife's entry in her published diary on 23 Nov 1863, stating it was a year ago he left with the horses.
Thank you and Alan for your help.