Nevada's Gabbs Formation preserves fossils from the Late Triassic and Early Jurassic and is one of the few formations in the United States to include the Triassic-Jurassic boundary. Its record of ammonites, bivalves, and other marine invertebrates makes it important for studying life across this major transition in Earth history. Several ammonites from the formation were newly described in 2021. An exposure at New York Canyon drew attention in 2007 as a proposed global reference point for the Hettangian, the first stage of the Jurassic. Although Austria's Kendlbach Formation was chosen instead in 2010, the Gabbs Formation remains a significant American record of the transition.