BISHOP CONGLOMERATE--Clasts of red quartzite, gray chert, and limestone in a gray to
     white tuffaceous sandstone matrix.  Tbi
WHITE RIVER FORMATION (AGE 31 TO 35 Ma)--White to pale-pink blocky tuffaceous
     claystone and lenticular arkosic conglomerate.  Twr
 Upper conglomerate member--Light-gray soft conglomeratic tuffaceous sandstone and
     conglomerate of Precambrian clasts.  Twru
 Brule Member--Pale-pink to white blocky tuffaceous claystone and lenticular sandstone.  
     Locally includes the upper conglomerate member.  Twrb
 Chadron Member--Light-gray to dark-red tuffaceous claystone, sandstone, and lenticular
     conglomerate.  Twrc