Actually the 2nd Arkansas Battalion at Seven Pines was assigned to Pettigrews Brigade. General Pettigrew was severely wounded and I believe taken Prisoner during the engagement. In Miears Diary he says that they were in Ransom Brigade. I am making a guess here that he confused about these two commanders since both were from North Carolina.

Richmond Daily Dispatch Newspaper
Friday morning...June 27, 1862.

To the Editors of the Dispatch:
The 35th Georgia in the battle of "Seven Pines"

On Saturday morning, the 31st of May, Gen. Pettigrew, with his brigade, composed of the 35th and 49th Georgia, 22d North Carolina, 47th Virginia, and 2d Arkansas battalion, left the encampment between the Meadow Bridge and Mechanicsville road, and moved down the Nine-Mile road toward the Chickahominy. Arriving near the scene of the day's action, the brigade, intended as a reserve force, was halted and allowed to rest two or three hours. About five in the afternoon the command was given for the brigade to move forward in double-quick time. The action had commenced some time before this, and the enemy had been driven from their entrenchments and camps in the first piece of woods. The brigade moved down the Nine-Mile road, turned to the left through the deserted camp of the enemy, entered the wheat field fronting the woods in which the enemy had planted a battery, and there formed the line of battle. Upon the 35th Georgia, commanded by Col. E. L. Thomas, which was the first regiment of the brigade to enter the field, fell the duty of bearing the brunt of the battle at this point. It was ordered to move forward and clear the woods in which the enemy's battery was placed, which order was executed in gallant style. When the regiment arrived within about fifty paces of the battery, under an appalling fire which came from an invisible foe, a retrograde movement on the part of some troops to the right swept back a portion of the right wing of the regiment, while the right of Hampton's Legion overlapped part of the left wing. While occupying this position, the regiment was exposed to a fierce and destructive cross fire from the enemy. Under this fire fell the gallant and noble General Pettigrew, in the woods fronting the battery, while urging on the troops to take the battery. Near him fell the young and gifted Lieut. Colonel of the 35th, Gustavas A. Bull. The Adjutant of the regiment, J. H. Ware, here had his horse shot under him while gallantly performing his duty. Under the terrible cross fire of the enemy, with its right wing swept back as above mentioned, and its left embarrassed by the right of Hampton's Legion, the 35th fell back. Its Colonel, E. L. Thomas, with a daring which brought back the confidence and courage of his wavering troops, seized the color of the regiment in his hands, rode in advance of his troops, and called on them to rally and follow their leader. Struck by the devoted conduct of then Colonel, the men rallied with enthusiasm under their banner, and again charged, but fell back under the deadly fire which poured forth from the battery. Again, and for the third time, their leader rallied and led them to the charge.
But it was in ruin — their courage and tenacity were not to prevail. Night coming on, the 35th withdrew slowly from the wood, immediately under the battery, to the Yankee camp, some three hundred yards distant, where the regiment passed the night. How the olivaceous Colonel of the 35th escaped death, seems a miracle. Exposed to the hottest of the fire from first to last, his position on horseback making him a conspicuous mark for the enemy's sharpshooters frequently in advance of his regiment, encouraging his men, he escaped, strange to say, without the smell of fire on his clothes. He has been in seven engagements, and came out of all unharmed.
I regret that I am not posted as to the particular parts played by the other regiments which compose the rest of the brigade in the stirring scenes of the day. They were ordered up to support the 35th when it made its charge on the battery. I have said little of them, because I am uninformed as to particulars. That they did is worthy of record, is well attested by the list of killed and wounded. In the whole brigade there were but two or three field officers who escaped unharmed and of the staff officers not one returned from the field without receiving a wound or having his horse shot under him.

During the Seven Days Battle they were assigned to Pender.