This is not what it appears to be (Jack Bell mooning in the direction the Confederates came up the road for the first shot of Gettysburg), but it is him inspecting the cannon that fired the first shot beneath Buford's statue:
Here is Dean sitting out of the strong wind atop Little Round Top. This is a couple feet from where Hazlett was killed. Gouverneur Warren's statue is in the backgroundt. Below and in the background is the Wheatfield and beyond. Basically this view is down the length of the Union lines.