The image is a vintage scientific illustration of a cross-section of an ammonite fossil. The ammonite is depicted as a spiral, with numerous chambers separated by septa. The chambers are filled with a textured, dark brown material, and the septa are visible as curved lines dividing the chambers. The overall color palette is pale yellow, brown, and sepia, giving the illustration a vintage feel. At the bottom of the image, there is text and a small geometric shape. The text reads "Pl. 2. 1863. Published by J. Sowerby, London." There is also a small square and a circle with lines inside. The number "12" is visible in the top right corner.