title: Panther Seep Formation
text: # Panther Seep Formation
  
  The Panther Seep Formation is a geologic formation found in the mountain ranges of south-central New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.
  
  ## Description
  
  The formation is highly variable in lithology, consisting of interbedded black to reddish sandy, silty, or calcareous shale; brown to olive calcareous siltstone, brown to gray calcareous arkosic sandstone; gypsum; and gray argillaceous to silty limestone. It varies in thickness from 200–2,640 feet (61–805 m). It overlies the Lead Camp Limestone or Bishop Cap Formation and is overlain by the Hueco Group.
  
  The unit likely correlates with Bar B Formation in the Caballo Mountains and the Holder Formation in the Sacramento Mountains.
  
  ## Fossils
  
  The formation includes patch reefs and numerous fusulinids of Virgilian (Gzhelian) age. The formation also contains algae and some invertebrate fossils typical of the Virgilian. The lower beds may be Missourian (Kasimovian) in age while the uppermost beds may be Wolfcampian (Cisuralian) in age.
  
  ## History of investigation
  
  The formation was first defined by F.E. Kottlowski and coinvestigators in 1956, who divided it into informal upper and lower members.
  
  