.0                                                                              
                SEDIMENTARY ROCKS OF TERTIARY AGE                               
                                                                                
                              EAST                                              
To     OGALLALA FORMATION--Loose to well-cemented sand and gravel               
Tgv    BOULDERY GRAVEL ON OLD EROSION SURFACES IN FRONT RANGE AND NEVER SUMMER  
         MOUNTAINS                                                              
Ta     ARIKAREE FORMATION--Sandstone; contains abundant volcanically derived    
         material                                                               
Twr    WHITE RIVER FORMATION OR GROUP--Ashy claystone and sandstone.  Includes  
         Castle Rock Conglomerate in region southeast of Denver                 
Th     HUERFANO FORMATION--Shale and sandstone.  Includes Farisita              
         Conglomerate in northwestern Huerfano County                           
Tcu    CUCHARA FORMATION--Sandstone and shale                                   
Tpc    POISON CANYON FORMATION--Arkosic conglomerate, sandstone, and shale      
Tdu    UPPER PART OF DAWSON ARKOSE--Arkosic sandstone, conglomerate, and        
         shale.  Includes Green Mountain Conglomerate south of Golden           
                                                                                
                            NORTHWEST                                           
Tbp    BROWNS PARK FORMATION--Sandstone and siltstone; west of Park Range       
Tt     TROUBLESOME FORMATION--Sandstone and siltstone; in Middle Park           
Tnp    NORTH PARK FORMATION--Sandstone, siltstone, and conglomerate; in North   
         Park and Laramie basin                                                 
Tos    OLIGOCENE SEDIMENTARY ROCKS--Includes Duchesne River Formation           
         (sandstone and shale; includes some rocks of Eocene age) and Bishop    
         Conglomerate near Utah border                                          
Twr    WHITE RIVER FORMATION--Ashy claystone and sandstone; in North Park       
Tu     UINTA FORMATION--Sandstone and siltstone; in Piceance basin.  Formerly   
         Evacuation Creek Member of Green River Formation                       
Tb     BRIDGER FORMATION--Claystone and mudstone; in Sand Wash basin            
Tg     GREEN RIVER FORMATION--Marlstone, sandstone, and oil shale               
Tgp     Parachute Creek Member--Oil shale, marlstone, and siltstone; in         
         Piceance basin                                                         
Tgl     Lower part--Shale, sandstone, marlstone, and limestone in Anvil         
         Points, Garden Gulch, and Douglas Creek Members; in Piceance basin     
Tglm    Laney Member--Claystone, oil shale, and sandstone; in Sand Wash basin   
Tgt     Tipton Tongue--Claystone and oil shale; in Sand Wash basin.  In         
         extreme northwest includes rocks of Wilkins Peak Member                
Tglu    Luman Tongue--Carbonaceous shale and marlstone; in Sand Wash basin      
Tglw   LOWER PART OF GREEN RIVER FORMATION AND WASATCH FORMATION--Shale and     
         sandstone                                                              
Tw     WASATCH FORMATION--Claystone, shale, and sandstone