The Llallagua Formation is a Rhuddanian to Homerian geologic formation of western Bolivia. The formation comprises siliciclastic sediments. The fossil fauna suggests a warm water, nearshore current was active allowing northern hemisphere benthos to exist in the formation.

The formation has provided the following fossils:

• List of fossiliferous stratigraphic units in Bolivia
  • Lipeón Formation

• G. Laubacher, A. J. Boucot, and J. Gray. 1982. Additions to Silurian stratigraphy, lithofacies, biogeography and paleontology of Bolivia and southern Peru. Journal of Paleontology 56(5):1138-1170