Tectonic Unit: mPPW
         Name: Purcell - Wernecke
 
  Description: mainly shallow-water, grey, green and red
               argillite, siltstone and orange and buff dolomite,
               locally stromatolitic and grey limestone grading
               from a clastic carbonate platform into offshelf,
               locally turbiditic, siltstone-quartzite and
               argillite; marine and nonmarine
 
    Formation: Omineca Belt
                  Ancestral North America
                       mP   Purcell: Mt. Nelson, La France Cr., Coppery Cr.,
                            Creston, Aldridge, Gateway, Nicol Cr., Van Cr.,
                            Kitchener, Ft. Steele, Belt: Missoula: Libby,
                            Bonner, Mt. Shields, Striped Pk., Wallace;
                            Ravalli: St. Regis, Spokane, Revett, Burke,
                            Prichard, Deer Trail
               Foreland Belt
                  Ancestral North America
                       mP   Wernecke: Gillespie L., Quartet, Fairchild L.;
                            Purcell: Roosville, Phillips, Gateway, Sheppard,
                            Purcell Lava, Siyeh, Grinell, Appekunny, Altyn,
                            Waterton, Tombstone Mtn., Haig, Brook, Belt:
                            Missoula: Garnet Range, McNamara, Bonner,
                            Mt. Shields, Shepard, Purcell Lava, Snowslip,
                            Helena; Spokane, Empire, Greyson, Altyn
    
    Age Range: Middle Proterozoic
  Maximum Age: 1600 Ma
  Minimum Age: 1000 Ma