A third Union brigade, under the command of Brigadier General John D. Stevenson, had held back in the rear because of dust clouds kicked up by Smith's brigade. As the battle grew in intensity, Stevenson began moving his men to a position behind the 8th Michigan Battery, but was ordered by McPherson to support Dennis and Smith when the Confederate attack hit. The brigade was split up, with the various regiments sent to different areas, depending on what was considered to be most threatened. On the Gallatin road, the two Confederate regiments on the flank prepared to attack the Union line with hopes of capturing McPherson's artillery. When some of the men of the 50th Tennessee opened fire on the Union line, the element of surprise was lost. The unit's commander also realized that the Union force was much larger than expected, and attempted to inform Gregg of this development. However, the messenger sent to find Gregg was unable to do so, and the message was not delivered. The unit then fell back to a defensive position without informing other Confederate units. On the other end of the Confederate line, an attack by the 20th Illinois Infantry Regiment drove back the 7th Texas. At this point in the fighting, the lines had realigned so that the Union troops held the of the creek east of the bridge and fired north, while on the other side of a curve in the creek, the Confederates held and fired south.