Sella Formation

The Sella Formation is a Dapingian to Darriwilian geologic formation of southern Bolivia. The grey to green bioturbated siltstones interbedded with thin sandstone layers bear lenticular shell beds. Other parts of the formation contain yellow-green limy shales and grey sandy limestones. Coquinas often fill gutter casts and included brachiopods, trilobites, bivalves and nautiloids. The sediments were deposited in an open marine environment.^{[1][2][3][4][5]} The species Coxiconchia sellaensis was named after the formation.

Sella Formation
Stratigraphic range: Dapingian-Darriwilian ~478–450 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Lithology
Primary	Siltstone, sandstone
Other	Shale, limestone, coquina
Location
Coordinates	21.4°S 64.6°W / -21.4; -64.6
Approximate paleocoordinates	42.8°S 131.6°W / -42.8; -131.6
Region	Tarija Department
Country	Bolivia
Sella Formation (Bolivia)

Fossil content

The formation has provided the following fossils:

• Baltograptus minutus^[6]
• Coxiconchia sellaensis
• Desmorthis segnis
• Glyptorthis imbrex
• Hemiprionodonta lusitanica
• Lingulocystis boliviensis
• Natasia boliviensis
• Pliomeridius sulcatus
• Redonia riojana
• Ribeiria spinosa
• Peelerophon cf. oehlerti
• Ampyx sp.
• Boeckaspis sp.
• Branisaspis sp.
• Bucania sp.
• Colpocoryphe sp.
• Cosmogoniophorina sp.
• Ctenodonta sp.
• Cyptendoceras sp.
• Didymograptus sp.
• Endoceras sp.
• Eothinoceras sp.
• Famatinolithus sp.
• Haploprimitia sp.
• Hoekaspis sp.
• Lecanospira sp.
• Lonchodomas sp.
• Maclurites sp.
• Quadrilobella sp.
• Parapyxion sp.
• Protocycloceras sp.
• Sibiritella sp.
• Suriaspis sp.
• Synhomalonotus sp.
• Technophorus sp.
• Trinucleus sp.

See also

• List of fossiliferous stratigraphic units in Bolivia