Austin Chalk

formation in the Gulf Coast region of the United States. It is named after type section outcrops near Austin, Texas. The formation is made up of chalk and marl.^[1]

galloanseran bird Austinornis lentus has been found in the Austin Chalk.^[2][3] The general absence of dinosaurs is a reflection of the Austin limestone being marine in origin, primarily composed of microscopic shell fragments from floating sea organisms known as "coccolithophores" (the same organisms that contributed to the White Cliffs of Dover, on the south coast of England).^[4] Nevertheless, the Austin Chalk will occasionally produce fossils of larger creatures, such as Inoceramus clams, ammonite cephalopods, and large marine vertebrates such as Xiphactinus, a predaceous