title: Barreirinha Formation
text: # Barreirinha Formation
  
  The Barreirinha Formation is a late Frasnian geologic formation of the Amazon Basin in the state of Amazonas of northern Brazil. The group comprises deep marine black shales and sandstones.
  
  ## Fossil content
  
  The formation has provided conodont fossils of:
  
  * Mehlina gradata
  * Ozarkodina aff. sannemanni
  * Cryptotaxis sp.
  * Polygnathus sp.
  * ?Prioniodina sp.
  