Antlers Formation
The Antlers Formation is a stratum which ranges from Arkansas through southern Oklahoma into northeastern Texas. The stratum is thick consisting of silty to sandy mudstone and fine to coarse grained sandstone that is poorly to moderately sorted. The stratum is cemented with clay and calcium carbonate. In places the sandstone may be conglomeratic or ferruginous (rich in iron oxides). Based on correlation with the Trinity Group of Texas, the Antlers Formation is estimated to be late Aptian-early Albian. This age range is supported by the presence of two dinosaurs that are also known from the Cloverly  Formation, "Deinonychus" and "Tenontosaurus". Amphibians. Indeterminate frog remains. Possible indeterminate salamander remains. Fish. References: Cifelli "et al." 1999; Wedel "et al." 2000, Kielan-Jarorowska and Cifelli 2001; Nydam and Cifelli 2002. Ray-finned fish. Possible indeterminate amid remains. Possible indeterminate lepisosteid remains. Possible indeterminate semionotidae remains. Mammals. Possible indeterminate deltatheroidan material. Indeterminate multituberculate remains. Indeterminate tribosphenidan remains. Reptiles. Crurotarsans. Possible indeterminate atoposaurid remains. Possible indeterminate goniopholidid remains. Possible indeterminate pholidosaurid remains. Lepidosaurs. Possible indeterminate scincid remains. Saurischians. Possible indeterminate bird remains are known from the formation.