Union General George H. Thomas' lines protecting Nashville against the advance of John Bell Hood. If you look closely at the left side of the picture, you can see the Nashville court house in the distance. The rifles are piled in "stacks" which allowed soldiers to not only keep their guns out of the mud, but also helped them get back into the battle line quickly. Visible in the picture is maybe a brigade's worth of soldiers (about 400-800 at this point in the war).
Susie King Taylor (August 6, 1848 - October 6, 1912) was an African American army nurse; she worked with black Union troops during the Civil War. As the author of Reminiscences of My Life in Camp with the 33d United States Colored Troops, Late 1st S.C. Volunteers, she was the only African American woman to publish a memoir of her wartime experiences. She was also the first African American to teach openly in a school for former slaves in Georgia.