Barton Creek / Zilker Park Austin Chalk exposures

Exposures of the Upper Cretaceous Austin Chalk and associated limestones are visible along Barton Creek within Zilker Park and the Barton Creek Greenbelt, and these bedrock exposures have produced marine fossils such as inoceramid bivalves, ammonite fragments, and shark teeth. Geologic guides to the Austin area cite these creek-side outcrops as local sites where Cretaceous marine fossils are found in place. These fossiliferous beds record the shallow marine environment that covered the Austin area during the Late Cretaceous.