Very interesting photo collage CDV published by Alexander Gardner. All photos I believe were taken c. 1864-1865. I recognize most of them but some I do not believe I have seen before which I will go into in my next posts.
If you want to reference a certain photo, you can use coordinates such as "A1" to identify the first photo at the very top, extreme left.
From Getty. Source: http://www.getty.edu/art/collection/objects/91476/alexander-gardner-copy-of-a-photo-collage-of-grant's-campaign-american-1864-1865/