| A seeker of Mesozoic paleontology explores geological exposures in Ammonite Canyon, Nevada; he is standing at the contact between the Upper Triassic portion of the Upper Triassic-Lower Jurassic Gabbs Formation, which here yields abundant and well preserved ammonoids, colonial scleractinian corals, gastropods, and pelecypods some 205 to 203 million years old (late Norian through early Rhaetian Stage geologic age) and the late lower Jurassic Dunlap Formation of Toarcian Stage age, approximately 180 million years old. The large brownish boulders are conglomerates and fanglomerates that belong to the terrestrial late Lower Jurassic Dunlap Formation; slope-forming strata directly behind the individual are shales that accumulated in the upper Triassic section of the upper Triassic-lower Jurassic Gabbs Formation. |