This early cabinet card has no information on it, but we can make a few reasonable assumptions. The cabinet card format was introduced in London in 1863 and in the United States in 1866. The two boys lying on the ground are wearing dark blue hats of the type worn by Union soldiers during the American Civil War (1861-1865). The hats, called kepis, must have been popular for some years afterward. The Confederate kepi was grey.
The presence of a dark-skinned young woman, who is presumably African American, also tells us this photo was likely taken in the North, rather than in the South, where schools were segregated by race. She looks older than most of the kids, as do two young women standing in the same row on the left side. Were they helping to tutor kids who weren’t at the same academic level as the rest of the group? Everyone in the photo is holding a book, but I haven’t been able to read the title, even at high magnification.
I’ve cropped the photo into several pieces, below, so you can see everyone in more detail.
Everyone in the group looks very dignified. For some of them, this may have been the first time they were ever photographed.