Tectonic Unit: CDRP
         Name: Rocky Mountains
 
  Description: resistant dolomite, limestone and local sandstone
               interbedded with recessive red, green and grey
               shale and detrital carbonate that together form
               several carbonate-shale grand cycles.  These pass
               westward into offshelf shale, siltstone and
               thin-bedded carbonate with minor alkalic tuff,
               breccia and amygdaloidal basalt of Cambrian (Cv),
               Cambro-Ordovician (COv), Silurian (Sv) and Devonian
               (Dv) ages but mainly of Ordovician (Ov) age.
               Chert and greywacke also occur in Cariboo
               subterrane; marine
 
    Formation: Foreland Belt
                  Porcupine Terrane
                       CD   unnamed mainly carbonate units spanning
                            Alaska-Yukon boundary
 
    Age Range: Cambrian - Devonian
  Maximum Age: 570.0 Ma
  Minimum Age: 362.5 Ma