Ron,

It is difficult to determine exactly which Federal units Johnson's men tackled, no easier in fact than most of the other Confederate divisions which attacked that day. That being said, in my opinion, Johnson's men hit the section of the Union line held by the 107th Illinois, 129th Indiana, and 23rd Michigan, troops from Orlando Moore's Brigade. Sharp's men, being on the front left when the attack began, may have hit the area defended by the Indiana and Michigan troops. I think this is supported by the fact that Brantley was on the rear left and his men took horrific casualties, likely the result of enfilading fire from the 23rd Michigan.

Unfortunately, the overall evidence is scanty. Hope this helps, at least somewhat.

Eric