Sella Formation
Geologic formation of southern Bolivia
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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 ~ | |
| Type | Geological formation |
| Lithology | |
| Primary | Siltstone, sandstone |
| Other | Shale, limestone, coquina |
| Location | |
| Coordinates | 21.4°S 64.6°W |
| Approximate paleocoordinates | 42.8°S 131.6°W |
| 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.