.0                                                                              
                                                                                
Tiql   INTRA-ASH-FLOW QUARTZ LATITIC LAVAS                                      
Tpl    PRE-ASH-FLOW ANDESITIC LAVAS, BRECCIAS, TUFFS, AND CONGLOMERATES         
         (GENERAL AGE 30-35 M.Y.)--Includes several named units                 
Twm    WALL MOUNTAIN TUFF (OLDER THAN TUFFS OF SAN JUAN PROVENANCE; AGE 35-36   
         M.Y.)--Early ash-flow tuff of Sawatch Range provenance                 
Tv     VOLCANIC ROCKS IN NORTHWESTERN COLORADO (AGE <7-33 M.Y.)--Mainly of      
         intermediate compositions                                              
Tui    UPPER TERTIARY INTRUSIVE ROCKS (AGE <20 M.Y.)--Intermediate to felsic    
         compositions                                                           
Tmi    MIDDLE TERTIARY INTRUSIVE ROCKS (AGE 20-40 M.Y.)--Intermediate to        
         felsic compositions