La Ciénega Formation is a Sandbian to Katian geologic formation of south-central Bolivia. The formation comprises silty, clayey, micaceous, fine-grained sandstones with thin intercalations of grey-green to light grey shales.

The formation has provided the following fossils:

• Dinorthis sp.
• Lingula sp.
• Lingulepis sp.
• Orbiculoidea sp.
• Orthoceras sp.

• List of fossiliferous stratigraphic units in Bolivia

• R. Suárez Soruco. 1976. El sistema ordovícico en Bolivia. Revista Tecnica YPF Bolivia 5(2):111-123