| A so-called "cannonball" ammonoid--genus Arcestes sp.--photographed as it resided in-situ (greenish-colored corners were later photoshopped in) in the upper Triassic portion of the upper Triassic-lower Jurassic Gabbs Formation, Ammonite Canyon, Nevada--in actual dimension, the ammonite is roughly 15 centimeters (6 inches) in diameter. Specimen came from the Rhaetian Stage of the Triassic Period, approximately 202 million years ago. |