Reportably this was taken at site of battle of Gaines Mills:
http://www.mikelynaugh.com/VirtualCivilWar/New/Originals2/pages/GainesMill.html
Are those entrenchments in the background?

"Wilderness" picture at http://en.wikipedia.org/wiki/File:SkullsAtWilderness1864.jpg
Taken near the Orange Plank Road?

Was this taken about the same time as "Cold Harbor" grave openings in 1865 by Reekie?
http://www.mikelynaugh.com/VirtualCivilWar/New/Originals2/pages/ColdHarborBones.html
Another "Cold Harbor" pictures?
http://en.wikipedia.org/wiki/File:ColdHarborBreastworks1864.jpg {What Extreme left would that be?}
http://en.wikipedia.org/wiki/File:ColdHarborBattlefield1864crop1.jpg