The Hueco Formation is a geologic formation in west Texas and southern New Mexico.Richardson 1904Richardson 1908Richardson 1914 It preserves fossils dating back to the early Permian period.Nelson 1940Bachman and Hayes 1958
Description The formation is composed most of massive gray fossiliferous limestone with some shale and sandstone, with a thickness in excess of . It overlies the Panther Seep FormationKelley and Matheny 1983 with a slight disconformity, and its base is typically a thick biostromal limestone bed.Kues and Giles 2004 The formation unconformably underlies the Wilkie Ranch Formation.Cys 1976 It intertongues with the Abo Formation in the southern San Andres Mountains.
In the Robledo Mountains, the Hueco is promoted to group rank and divided into (in ascending stratigraphic order) the Shalem Colony, Community Pit, Robledo Mountains, and Apache Dam Formations.Lucas et al. 1998 In the Hueco Mountains, the uppermost formation is the Alacran Mountain Formation.Williams 1963
The Hueco Formation is contemporary with the Abo Formation and represents continued marine sediment deposition south of the prograding Abo deltas.
History of investigation The formation was first defined by G.B. Richardson in 1904, but mistakenly thought to be Pennsylvanian in age. Nelson dated the formation as earliest Permian in the Franklin Mountains in 1940. Spencer G. Lucas et al. promoted the formation to group rank in 1998.
See also
List of fossiliferous stratigraphic units in Texas Paleontology in Texas
Footnotes
Bibliography