This document is a representation of the legend that accompanied the

original 1974 King and Beikman Geology of the United States.  It is in

plain text and there are no colors or patterns in the unit boxes. 

 

 

                                                                                                                               LEGEND

 

 

                                      STRATIFIED SEQUENCE                                                                EUGEOSYNCLINAL                                                                  PLUTONIC AND                     METAMORPHIC

                                        (Mainly marine)                              CONTINENTAL DEPOSITS                   DEPOSITS                              VOLCANIC ROCKS                        INTRUSIVE ROCKS                      ROCKS

                                                                                                                                                                                                                    

                   +------------------------------------------------------------+ +-----------------------+ +---------------------------------------+ +---------------------------------------+ +----------------------------------+ +------------------+

 

                                                                                 ¦                         ¦                                         ¦                                         ¦                                    ¦                  

                         Most complete                            Combinations                                                                                                                                                                           

   +                       sequences                                             ¦                         ¦                                         ¦                                         ¦                                    ¦                    

   ¦         +                          +                                                                                                                                                                                                                

   ¦         ¦       +------+           ¦ Atlantic                               ¦                         ¦                                         ¦                                         ¦                                    ¦                    

   ¦         ¦       ¦  Qh  ¦           ¦ and                                                                                                                                                                                                            

   ¦         ¦       +------+           ¦ Gulf                                   ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       HOLOCENE           ¦ Coastal                                                                                                                                                                                                      

   ¦         ¦                          ¦ Plains                                 ¦                         ¦                                         ¦                                         ¦                                    ¦                   

   ¦         ¦       +------+           ¦ and                         +                                                                                                                                                                                

   ¦         ¦       ¦  Qp  ¦           ¦ part          +------+      ¦          ¦                         ¦                                         ¦            +-------------+              ¦                                    ¦                  

   ¦         ¦       +------+           ¦ of            ¦  Q   ¦      ¦                                                                                           ¦  Qv  ¦  Qf  ¦                                                                      

   ¦         ¦       PLEISTOCENE        ¦ Great         +------+      ¦          ¦                         ¦                                         ¦            +-------------+              ¦                                    ¦                  

   ¦       Q ¦       Glacial deposits   ¦ Plains.       QUATERNARY    ¦ Western                                                                                   QUATERNARY                                                                           

   ¦       U ¦       not included,      ¦               Only large    ¦ United   ¦                         ¦                                         ¦            VOLCANIC ROCKS               ¦                                    ¦                  

   ¦       A ¦       see below.         +               areas and     ¦ States.                                                                                   Qf, Felsic volcanic                                                                  

   ¦       T ¦                                          thick         ¦          ¦                         ¦                                         ¦            rocks.                       ¦                                    ¦                  

   ¦       E ¦       +------+           +               deposits      ¦                                                                                                                                                                                

   ¦       R ¦       ¦      ¦           ¦               shown.        ¦          ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦       N ¦       +------+           ¦                             +                                                                                                                                                                                

   ¦       A ¦       LIMITS OF          ¦                                        ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦       R ¦       PLEISTOCENE        ¦                                                                                                                                                                                                               

   ¦       Y ¦       GLACIAL DEPOSITS   ¦ Northern                               ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       Solid line,        ¦ interior                                                                                                                                                                                                      

   ¦         ¦       Wisconsin  gla-    ¦ region,                                ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       ciations; broken   ¦ Pennsylvania                                                                                                                                                                                                  

   ¦         ¦       line, older        ¦ to                                     ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       glaciations.       ¦ Montana.                                                                                                                                                                                                      

   ¦         ¦       North of these     ¦                                        ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       lines, extensive   ¦                                                                                                                                                                                                               

   ¦         ¦       areas of bedrock   ¦                                        ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       are concealed.     ¦                                                                                                                                                                                                               

   ¦         +                          +                                        ¦                         ¦                                         ¦                                         ¦                                    ¦                  

C  ¦           --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --

   ¦         +                                                                   ¦                         ¦                                         ¦                                         ¦                                    ¦                  

E  ¦         ¦       +------+                                                       +------+                                                            +-------------+                                                                                

   ¦         ¦       ¦  Tp  ¦                                                    ¦  ¦ Tpc  ¦               ¦                                         ¦  ¦ Tpv  ¦ Tpf  ¦                        ¦                                    ¦                  

N  ¦         ¦       +------+                                                       +------+                                                            +-------------+                                                                                 

   ¦         ¦       PLIOCENE                                                    ¦  PLIOCENE CONTINENTAL   ¦                                         ¦  PLIOCENE                    +          ¦                                    ¦                  

O  ¦         ¦                          +                                           DEPOSITS                                                            VOLCANIC ROCKS    +------+  ¦             +------+                                             

   ¦         ¦       +------+           ¦ Includes                               ¦  Includes Miocene and   ¦                                         ¦  Tpf, Felsic       ¦ uTa  ¦  ¦          ¦  ¦  Ti  ¦                          ¦                  

Z  ¦         ¦       ¦  Tm  ¦           ¦ Pliocene                                  Quaternary deposits                                                 volcanic rocks.   +------+  ¦             +------+                                             

   ¦         ¦       +------+           ¦ in                                     ¦  in places.             ¦                                         ¦                    UPPER     ¦ Cascade  ¦  TERTIARY                          ¦                  

O  ¦         ¦       MIOCENE            ¦ Southeastern                                                                        +                         +-------------+   TERTIARY  ¦ Range       INTRUSIVE                                             

   ¦         ¦       Pliocene included  ¦ U.S.                                   ¦  +------+               ¦  +------+        ¦                      ¦  ¦ Tmv  ¦ Tmf  ¦   ANDESITE  ¦ of       ¦  ROCKS                             ¦                  

I  ¦         ¦       in places.         ¦                                           ¦ Tmc  ¦                  ¦ Tmoe ¦        ¦                         +-------------+             ¦ Wash-       Plugs, stocks,                                        

   ¦         ¦                          +                                        ¦  +------+               ¦  +------+        ¦                      ¦  MIOCENE           +------+  ¦ ington   ¦  and laccoliths                    ¦                  

C  ¦         ¦       +------+                                                       MIOCENE CONTINENTAL       MIOCENE AND     ¦                         VOLCANIC ROCKS    ¦ lTa  ¦  ¦ and         of all Tertiary                                       

   ¦         ¦       ¦  To  ¦                                                    ¦  DEPOSITS               ¦  OLIGOCENE       ¦                      ¦  Tmf, Felsic       +------+  ¦ Oregon.  ¦  ages; some                        ¦                   

   ¦         ¦       +------+                                                                                 EUGEOSYNCLINAL  ¦                         volcanic rocks.   LOWER     ¦             granite plutons                                       

   ¦         ¦       OLIGOCENE                                                   ¦  +------+               ¦  DEPOSITS        ¦ Olympic              ¦                    TERTIARY  ¦          ¦  of early to                       ¦                  

   ¦       T ¦    +                     +                                           ¦ Toc  ¦                                  ¦ Pennin-                 +-------------+   ANDESITE  ¦             middle Tertiary                                      

   ¦       E ¦    ¦  +------+           ¦                                        ¦  +------+               ¦  +------+        ¦ sula,                ¦  ¦ lTv  ¦ lTf  ¦             +          ¦  age.                              ¦                  

   ¦       R ¦    ¦  ¦ Te3  ¦           ¦                                           OLIGOCENE CONTINENTAL     ¦ Toee ¦        ¦ Wash-                   +-------------+                                                                                

   ¦       T ¦    ¦  +------+           ¦                                        ¦  DEPOSITS               ¦  +------+        ¦ ington.              ¦  LOWER TERIARY                          ¦                                    ¦                  

   ¦       I ¦    ¦  JACKSON GROUP      ¦                                                                     OLIGOCENE AND   ¦                         VOLCANIC ROCKS                                                                                 

   ¦       A ¦  E ¦                     ¦ Atlantic                               ¦  +------+               ¦  EOCENE          ¦                      ¦  Oligocene and Eocene;                  ¦                                    ¦                  

   ¦       R ¦  O ¦  +------+           ¦ and           +------+                    ¦ Tec  ¦                  EUGEOSYNCLINAL  ¦                         some Cretaceous                                                                                

   ¦       Y ¦  C ¦  ¦ Te2  ¦           ¦ Gulf          ¦  Te  ¦                 ¦  +------+               ¦  DEPOSITS        ¦                      ¦  included in Arizona                    ¦                                    ¦                  

   ¦         ¦  E ¦  +------+           ¦ Coastal       +------+                    EOCENE CONTINENTAL                        ¦                         and elsewhere.                                                                                

   ¦         ¦  N ¦  CLAIBORNE GROUP    ¦ Plains.       EOCENE                   ¦  DEPOSITS               ¦  +------+        ¦                      ¦  lTf, Felsic volcanic                   ¦                                    ¦                  

   ¦         ¦  E ¦                     ¦                                                                     ¦ Tee  ¦        ¦                         rocks in southwestern                                                                          

   ¦         ¦    ¦  +------+           ¦                                        ¦  +------+               ¦  +------+        ¦                      ¦  Colorado and New Mexico.               ¦                                    ¦                  

   ¦         ¦    ¦  ¦ Te1  ¦           ¦                                           ¦ Tel  ¦                  EOCENE          ¦                                     +                                                                                  

   ¦         ¦    ¦  +------+           ¦                                        ¦  +------+               ¦  EUGEOSYNCLINAL  ¦                      ¦  +--------+  ¦ Coast                    ¦                                    ¦                  

   ¦         ¦    ¦  WILCOX GROUP       ¦                                           EOCENE LACUSTRINE         DEPOSITS        ¦                         ¦  Teb   ¦  ¦ Ranges                                                                           

   ¦         ¦    +                     +                                        ¦  DEPOSITS               ¦                  +                      ¦  +--------+  ¦ of                       ¦                                    ¦                  

   ¦         ¦       +------+                                                                                                                           EOCENE      ¦ Wash-                                                                            

   ¦         ¦       ¦  Tx  ¦                                                    ¦  +------+               ¦                                         ¦  MARINE      ¦ ington                   ¦                                    ¦                  

   ¦         ¦       +------+                                                       ¦ Txc  ¦                                                            PILLOW      ¦ and                                                                              

   ¦         ¦       PALEOCENE                                                   ¦  +------+               ¦                                         ¦  BASALT      ¦ Oregon.                  ¦                                    ¦                  

   ¦         ¦       Includes Midway                                                PALEOCENE CONTINENTAL                                                           +                                                                                  

   ¦         ¦       Group of Gulf                                               ¦  DEPOSITS               ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       Coastal Plain.                                                                                                                                                                                                                     

   +         +                                                                   ¦                         ¦                                         ¦                                         ¦                                    ¦                  

     --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  -

                                                                                 ¦                         ¦                                         ¦                                         ¦                                    ¦                  

   +         +    +                     +                                                                                                                                                         +------+       +                                     

   ¦         ¦    ¦                     ¦                                        ¦                         ¦                                         ¦                                         ¦  ¦ Kg3  ¦       ¦                  ¦                  

   ¦         ¦    ¦  +------+           ¦                                                                                                                                                         +------+       ¦                                     

   ¦         ¦    ¦  ¦ uK4  ¦           ¦                                        ¦                         ¦                                         ¦                                         ¦  LATEST         ¦                  ¦                  

   ¦         ¦    ¦  +------+           ¦                                                                                                                                                         CRETACEOUS     ¦                                     

   ¦         ¦    ¦  NAVARRO GROUP      ¦                                        ¦                         ¦                                         ¦                                         ¦  GRANITIC       ¦ Arizona,         ¦                  

   ¦         ¦    ¦  (=Laramie and      ¦                                                                                                                                                         ROCKS          ¦ Colorado,                           

   ¦         ¦    ¦  other formations)  ¦                                        ¦                         ¦                                         ¦                                         ¦  Laramide gran- ¦ and              ¦                  

   ¦         ¦    ¦                     ¦                                                                                                                                                         itic rocks of  ¦ Montana.                            

   ¦         ¦    ¦  +--------+         ¦                                        ¦                         ¦                                         ¦                                         ¦  common usage.  ¦                  ¦                  

   ¦         ¦    ¦  ¦   ¦uK3b¦         ¦                                                                                                                                                         Mainly 70 to   ¦                                      

   ¦         ¦    ¦  ¦uK3+----¦         ¦                                        ¦                         ¦                                         ¦                                         ¦  80 my, but     ¦                  ¦                  

   ¦         ¦    ¦  ¦   ¦uK3a¦         ¦                                                                                                                                                         includes early ¦                                      

   ¦         ¦    ¦  +--------+         ¦                                        ¦                         ¦                  +                      ¦                                         ¦  Tertiary in    ¦                  ¦                   

   ¦         ¦  U ¦  TAYLOR GROUP       ¦                                                                     +------+        ¦                                    +                              places.        +                                      

   ¦         ¦  P ¦  (=Montana Group)   ¦                                        ¦                         ¦  ¦  Ke  ¦        ¦                      ¦ +------+    ¦                           ¦                                    ¦                   

   ¦         ¦  P ¦  In Montana plains, ¦                                                                     +------+        ¦                        ¦  Kv  ¦    ¦ Montana,                     +------+       +                                     

   ¦         ¦  E ¦  separated into     ¦ Atlantic                               ¦                         ¦  CRETACEOUS      ¦                      ¦ +------+    ¦ Arizona,                  ¦  ¦ Kg2  ¦       ¦                  ¦                  

   ¦         ¦  R ¦  uK3a and b at      ¦ and                                                                 EUGEOSYNCLINAL  ¦ North-                 CRETACEOUS  ¦ and New                      +------+       ¦                                     

   ¦         ¦    ¦  base of Judith     ¦ Gulf                                   ¦                         ¦  DEPOSITS        ¦ western              ¦ VOLCANIC    ¦ Mexico.                   ¦  UPPER          ¦                  ¦                  

   ¦         ¦    ¦  River Formation.   ¦ Coastal                                                             Mainly Upper    ¦ Cali-                  ROCKS       ¦                              CRETACEOUS     ¦                                     

   ¦         ¦    ¦                     ¦ Plains                                 ¦                         ¦  Cretaceous,     ¦ fornia.              ¦             +                           ¦  GRANITIC       ¦                  ¦                  

   ¦         ¦    ¦  +------+           ¦ and           +------+                                              some Paleocene  ¦                                                                   ROCKS          ¦                                     

   ¦         ¦    ¦  ¦ uK2  ¦           ¦ western       ¦  uK  ¦                 ¦                         ¦  and Eocene.     ¦                      ¦                                         ¦  80-90 my       ¦ Sierra           ¦                  

   ¦       C ¦    ¦  +------+           ¦ interior      +------+                                                              +                                                                                  ¦ Nevada,       ^                     

   ¦       R ¦    ¦  AUSTIN AND EAGLE   ¦ region.       UPPER CRETACEOUS         ¦  +------+               ¦                                         ¦                                         ¦  +------+       ¦ California.   ¦  ¦                  

   ¦       E ¦    ¦  FORD GROUPS        ¦                                           ¦  Kc  ¦                                                                                                      ¦ Kg1  ¦       ¦               ¦                     

   ¦       T ¦    ¦  (=Colorado Group)  ¦                                        ¦  +------+               ¦                                         ¦                                         ¦  +------+       ¦               ¦  ¦                  

   ¦       A ¦    ¦                     ¦                                           CRETACEOUS                                                                                                    LOWER          ¦               ¦                     

   ¦       C ¦    ¦  +------+           ¦                                        ¦  CONTINENTAL DEPOSITS   ¦                                         ¦                                         ¦  CRETACEOUS     ¦               ¦  ¦                  

   ¦       E ¦    ¦  ¦ uK1  ¦           ¦                                           Includes Upper and                                                                                            GRANITIC       ¦               ¦                     

   ¦       O ¦    ¦  +------+           ¦                                        ¦  Lower Cretaceous,      ¦                                         ¦                                         ¦  ROCKS          ¦               /  ¦                  

   ¦       U ¦    ¦  WOODBINE AND       ¦                                           depending on                                                                                                  105-120 my     +              /                      

   ¦       S ¦    ¦  TUSCALOOSA GROUPS  ¦                                        ¦  locality.              ¦                                         ¦                                         ¦                               /    ¦                  

   ¦         ¦    ¦  (=Dakota Group)    ¦                                                                                                                                                          +-----------------------------+                     

   ¦         ¦    ¦  Lower Cretaceous   ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦                             ¦  ¦                  

   ¦         ¦    ¦  included in parts  ¦                                                                                                                                                          ¦ +-------------+  +          ¦                     

   ¦         ¦    ¦  of Rocky Mountain  ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦ ¦  Kg  ¦ Kgn  ¦  ¦          ¦  ¦                  

   ¦         ¦    ¦  and High Plains    ¦                                                                                                                                                          ¦ +-------------+  ¦ Western  ¦                     

M  ¦         ¦    +  regions.           +                                        ¦                         ¦                                         ¦                                         ¦   ¦ CRETACEOUS       ¦ United   ¦  ¦                  

   ¦         ¦                                                                                                                                                                                     ¦ GRANITIC ROCKS   ¦ States.  ¦                     

E  ¦         ¦    +  +------+           +                                        ¦                         ¦                                         ¦                                         ¦   ¦ Kgn, border      ¦          ¦  ¦                  

   ¦         ¦    ¦  ¦ lK3  ¦           ¦                                                                                                                                                          ¦ gneiss of Idaho  ¦          ¦                     

S  ¦         ¦    ¦  +------+           ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦ batholith.       +          ¦  ¦                  

   ¦         ¦    ¦  WASHITA GROUP      ¦                                                                                                                                                          ¦                             ¦                     

O  ¦         ¦  L ¦                     ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦ +------+         +          ¦  ¦                  

   ¦         ¦  O ¦  +------+           ¦               +------+                                                                                                                                   ¦ ¦  Ki  ¦         ¦          ¦                     

Z  ¦         ¦  W ¦  ¦ lK2  ¦           ¦ Texas.        ¦  lK  ¦                 ¦                         ¦                                         ¦                                         ¦   ¦ +------+         ¦          ¦  ¦                  

   ¦         ¦  E ¦  +------+           ¦               +------+                                                                                                                                   ¦ CRETACEOUS       ¦          ¦                     

O  ¦         ¦  R ¦  FREDERICKSBURG     ¦               LOWER CRETACEOUS         ¦                         ¦                                         ¦                                         ¦   ¦ INTRUSIVE        ¦ Arkansas.¦  ¦                  

   ¦         ¦    ¦  GROUP              ¦                                                                                                                                                          ¦ ROCKS            ¦          ¦                     

I  ¦         ¦    ¦                     ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦ Small plugs      ¦          ¦  ¦                  

   ¦         ¦    ¦  +------+           ¦                                                                                                                                                          ¦ and stocks of    ¦          ¦                     

C  ¦         ¦    ¦  ¦ lK1  ¦           ¦                                        ¦                         ¦                                         ¦                                         ¦   ¦ alkalic rocks.   +          ¦  ¦                  

   ¦         ¦    ¦  +------+           ¦                                                                                                                                                          ¦                             ¦                     

   ¦         ¦    +  TRINITY GROUP      +                                        ¦                         ¦  +------+        +                      ¦                                         ¦   +-----------------------------+  ¦                  

   ¦         +                                                                                                ¦ uMze ¦        ¦                                                                                                                         

   ¦           --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  - ¦--  --  --  --  --  --  -+  +------+--  -- -+  --  --  --  --  --  +-  --  --  --  --  --  --  --  --  --  --¦ --  --  --  --  --  --  --  --  -- ¦--  --  --  --  --  --  -

   ¦       J +                                                                                  +             UPPER MESOZOIC  ¦                                                                                                                         

   ¦       U ¦       +------+                                                    ¦  +------+    ¦ Minne-   ¦  EUGEOSYNCLINAL  ¦ Western              ¦ +------+    + Central                   ¦  +------+                          ¦  +------+         

   ¦       R ¦       ¦  J   ¦                                                       ¦  Jc  ¦    ¦ sota,       DEPOSITS        ¦ Calif-                 ¦ lMzv ¦    ¦ Nevada,                      ¦  Jg  ¦                             ¦      ¦        

   ¦       A ¦       +------+                                                    ¦  +------+    ¦ Iowa,    ¦  Lower Cretaceous¦ ornia,               ¦ +------+    ¦ southern                  ¦  +------+  +------+  +             ¦  +------+        

   ¦       S ¦       JURASSIC                                                       JURASSIC    ¦ and         to Upper Jur-   ¦ Oregon,                LOWER       ¦ Arizona,                     JURASSIC  ¦ Jmi  ¦  ¦                AREAS OF        

   ¦       S ¦                                                                   ¦  CONTINENTAL ¦ Mich-    ¦  assic, but with ¦ and                  ¦ MESOZOIC    ¦ and New                   ¦  GRANITIC  +------+  ¦ Western     ¦  PHANEROZOIC     

   ¦       I ¦       +------+           +               +------+                    DEPOSITS    ¦ igan.       uncertain lim-  ¦ Wash-                  VOLCANIC    ¦ Hampshire.                   ROCKS     JURASSIC  ¦ Nevada.        METAMORPHISM    

   ¦       C +       ¦ JTr  ¦           ¦ Colorado      ¦ lMz  ¦                 ¦              +          ¦  its; includes   ¦ ington.              ¦ ROCKS       +                           ¦            MAFIC     ¦             ¦  Shown by over-  

   ¦         +       +------+           ¦ Plateau.      +------+                                              Franciscan as-  ¦                                                                             INTRUS-   ¦                print pattern;  

   ¦         ¦       LOWER JURASSIC AND ¦               LOWER MESOZOIC           ¦                         ¦  semblage of     ¦                      ¦ +------+    +                           ¦            IVES      +             ¦  generally of    

   ¦         ¦       UPPER TRIASSIC     ¦                                                                     California.     +                        ¦ Trv  ¦    ¦                              +------+                             amphibolite     

   ¦         ¦       Glen Canyon Group. +                                        ¦                         ¦                                         ¦ +------+    ¦ Central                   ¦  ¦ Trg  ¦                          ¦  grade or higher,

   ¦       T ¦                                                                                                +------+        +                        MAFIC LAVA  ¦ Appalachians                 +------+                             but distinctions

   ¦       R ¦       +------+                                                    ¦                         ¦  ¦ lMze ¦        ¦                      ¦ INTERBEDDED ¦ and                       ¦  TRIASSIC  +------+  +             ¦  are relative.   

   ¦       I ¦       ¦ Tr   ¦                                                                                 +------+        ¦                        IN TRIASSIC ¦ New England.                 GRANITIC  ¦ Tri  ¦  ¦                Includes higher 

   ¦       A ¦       +------+                                                    ¦                         ¦  LOWER MESOZOIC  ¦ Western              ¦ NEWARK      ¦                           ¦  ROCKS     +------+  ¦             ¦  grade blueschist

   ¦       S ¦       TRIASSIC                                                                                 EUGEOSYNCLINAL  ¦ United                 GROUP       +                                        TRIASSIC  ¦ Appa-          metamorphic     

   ¦       S ¦       Mainly marine, but includes                                 ¦                         ¦  DEPOSITS        ¦ States.              ¦                                         ¦            MAFIC     ¦ lachian     ¦  rocks near west 

   ¦       I ¦       continental Dockum Group in                                                              Middle and      ¦                                                                             INTRUS-   ¦ region.        coast.          

   ¦       C ¦       Texas and New Mexico, and                                   ¦                         ¦  Lower           ¦                      ¦                                         ¦            IVES      ¦             ¦                  

   ¦         ¦       Newark Group in Appalachian                                                              Jurassic and    ¦                                                                             In Newark ¦                                

   ¦         ¦       region.                                                     ¦                         ¦  Triassic.       +                      ¦                                         ¦            Group.    +             ¦                  

   +         +                                                                                                                                                                                                                                          

     --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  -- -+  --  --  --  --  --  -- ¦--+------+  -- -- +--  --  --  --  --  --¦ --  --  --  --  --  --  --  --  --  --  +-  --  --  --  --  --  --  --  --  -+  --  --  --  --  --  --

   +         +                     +                        +                                                 ¦ TrPe ¦        ¦                                                                                                                        

   ¦         ¦       +------+      ¦              +------+  ¦                    ¦                         ¦  +------+        ¦ Oregon,              ¦                                         ¦                                    ¦                  

   ¦         ¦       ¦  P4  ¦      ¦              ¦  P4  ¦  ¦                                                 TRIASSIC AND    ¦ Cali-                                                                                                                   

   ¦         ¦       +------+      ¦ Mid-         +------+  ¦                    ¦                         ¦  PERMIAN         ¦ fornia,              ¦                                         ¦                                    ¦                  

   ¦         ¦       OCHOAN        ¦ continent    OCHOAN    ¦                                                 EUGEOSYNCLINAL  ¦ and                                                                                                                     

   ¦         ¦       SERIES        ¦ region       SERIES    ¦                    ¦                         ¦  DEPOSITS        ¦ Nevada.              ¦                                         ¦        +                           ¦                  

   ¦         ¦       +------+      ¦ (central               ¦ West                                            Dominantly      ¦                                                                         ¦  +------+                                    

   ¦         ¦       ¦ P3b  ¦      ¦ Texas to               ¦ Texas              ¦                         ¦  volcanic.       +                      ¦                                         ¦        ¦  ¦      ¦                 ¦                  

   ¦         ¦       +------+      ¦ Kansas),               ¦ standard.                                                                                                                                 ¦  +------+                                    

   ¦         ¦       UPPER PART OF ¦ New Mexico,  +------+  ¦                    ¦                         ¦                                         ¦                                         ¦        ¦  DIKES                    ¦                  

   ¦         ¦       GUADALUPIAN   ¦ and          ¦  P3  ¦  ¦                                                                                                                                           ¦  Mainly Triassic in                          

   ¦         ¦       SERIES        ¦ northern     +------+  ¦                    ¦                         ¦                                         ¦                                         ¦        ¦  Appalachian region,      ¦                  

   ¦       P ¦       +------+      ¦ Arizona.     GUADALUP- ¦                                                                                                                                           ¦  Precambrian in                              

   ¦       E ¦       ¦ P3a  ¦      ¦ Note-        IAN       ¦                    ¦                         ¦                                         ¦                                         ¦  Units ¦  Minnesota, Tertiary      ¦                  

   ¦       R ¦       +------+      ¦ Subdivisions SERIES    ¦           +                                                     +                                                                   not   ¦  in western United                           

   ¦       M ¦       LOWER PART OF ¦ of                     ¦ +------+  ¦        ¦                         ¦  +------+        ¦                      ¦                                         ¦  dif-  ¦  States.                  ¦                  

   ¦       I ¦       GUADALUPIAN   ¦ Guadalupian            ¦ ¦  P   ¦  ¦ Colo-                 +             ¦  Pe  ¦        ¦ Klamath                                                           feren-¦                                               

   ¦       A ¦       SERIES        ¦ and                    ¦ +------+  ¦ rado   ¦  +------+    ¦          ¦  +------+        ¦ Mount-               ¦                                         ¦  tiated¦  +------+                 ¦                  

   ¦       N ¦       +------+      ¦ Leonardian             ¦ PERMIAN   ¦ Plateau   ¦ P2ac ¦    ¦             PERMIAN         ¦ ains                                                              as to ¦  ¦  um  ¦                                     

   ¦         ¦       ¦ P2b  ¦      ¦ Series are             ¦ Smaller   ¦ and    ¦  +------+    ¦          ¦  EUGEOSYNCLINAL  ¦ and                  ¦                                         ¦  age.  ¦  +------+                 ¦                   

   ¦         ¦       +------+      ¦ operational            ¦ areas     ¦ Great     CONTINENTAL ¦             DEPOSITS        ¦ North-                                                                  ¦  ULTRAMAFIC ROCKS                             

   ¦         ¦       UPPER PART OF ¦ units,       +------+  ¦ included  ¦ Basin. ¦  DEPOSITS    ¦          ¦  Mostly not      ¦ ern                  ¦                                         ¦        ¦  Of Paleozoic age in      ¦                  

   ¦         ¦       LEONARDIAN    ¦ which        ¦  P2  ¦  ¦ in undif- ¦           OF EARLY    ¦ Northern    separated from  ¦ Sierra                                                                  ¦  Appalachian region;                         

   ¦         ¦       SERIES        ¦ are not      +------+  ¦ feren-    ¦        ¦  LEONARDIAN  ¦ Texas,   ¦  undifferentiated¦ Nevada,              ¦                                         ¦        ¦  of upper Paleozoic       ¦                  

   ¦         ¦       +------+      ¦ necessarily  LEONARD-  ¦ tiated    ¦           AGE         ¦ southern    upper Paleozoic ¦ Cali-                                                                   ¦  and Mesozoic age                            

   ¦         ¦       ¦ P2a  ¦      ¦ correlative  IAN       ¦ upper     ¦        ¦              ¦ Okla-    ¦  eugeosynclinal  ¦ fornia.              ¦                                         ¦        ¦  in western United        ¦                  

   ¦         ¦       +------+      ¦ from one     SERIES    ¦ Paleozoic.+           +------+    ¦ homa,       deposits.       ¦                                                                         ¦  States; a few of                            

   ¦         ¦       LOWER PART OF ¦ area to                ¦                    ¦  ¦ P1c  ¦    ¦ and      ¦                  +                      ¦                                         ¦        ¦  Precambrian age.         ¦                  

   ¦         ¦       LEONARDIAN    ¦ another;               ¦                       +------+    ¦ New                                                                                                   +                                              

   ¦         ¦       SERIES        ¦ see          +------+  ¦                    ¦  CONTINENTAL ¦ Mexico.  ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       +------+      ¦ diagram.     ¦  P1  ¦  ¦                       DEPOSITS    ¦                                                                                                                                                      

   ¦         ¦       ¦  P1  ¦      ¦              +------+  ¦                    ¦  OF          ¦          ¦                                         ¦                                         ¦                                    ¦                  

   ¦         ¦       +------+      ¦              WOLFCAMP- ¦                       WOLFCAMPIAN ¦                                                                                                                                                      

   ¦         ¦       WOLFCAMPIAN   +              IAN       ¦                    ¦  AGE         ¦          ¦                                         ¦                                         ¦                                    ¦                  

   ¦         +       SERIES                       SERIES    +                                   +                                                                                                                                                      

   ¦      --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  -+  --  --  --  --  --  -- --  --  --  --  +-  --  --  --  --  --  --  --  --  --  --¦ --  --  --  --  --  --  --  --  -- ¦--  --  --  --  --  --  -

   ¦    +    +    +                     +                                                                                                                                                                     +                                 +      

   ¦    ¦    ¦    ¦  +------+           ¦                                        ¦                         ¦                                         ¦                                         ¦  +------+    ¦                     ¦  +------+ ¦      

   ¦    ¦    ¦    ¦  ¦ PP4  ¦           ¦                                                                                                                                                         ¦ Pzg3 ¦    ¦                        ¦ cat  ¦ ¦      

   ¦    ¦    ¦    ¦  +------+           ¦                                        ¦                         ¦                                         ¦                                         ¦  +------+    ¦                     ¦  +------+ ¦      

   ¦    ¦    ¦    ¦  VIRGILIAN SERIES   ¦                                                                                                                                                         UPPER       ¦                        CATA-    ¦      

   ¦    ¦    ¦  U ¦  (= Monongahela     ¦ Central                                ¦                         ¦                                         ¦                                         ¦  PALEOZOIC   ¦                     ¦  CLASTIC  ¦ Pied-

   ¦    ¦    ¦  P ¦  Group)             ¦ interior                                                                                                                                                GRANITIC    ¦                        ROCKS    ¦ mont 

   ¦    ¦    ¦  P ¦                     ¦ region, from                           ¦                         ¦                                         ¦                                         ¦  ROCKS       ¦                     ¦  Produced ¦ prov-

   ¦    ¦    ¦  E ¦  +------+           ¦ Appalachians                                                                                                                                            About 250-  ¦                        by       ¦ ince.

   ¦    ¦    ¦  R ¦  ¦ PP3  ¦           ¦ to Kansas                              ¦                         ¦                                         ¦                                         ¦  300 my.     ¦                     ¦  Paleo-   ¦      

   ¦    ¦  P ¦    ¦  +------+           ¦ and central                                                                                                                                             Mainly in   ¦                        zoic or- ¦      

   ¦    ¦  E ¦    ¦  MISSOURIAN SERIES  ¦ Texas.                                 ¦                         ¦                                         ¦                                         ¦  southeast   ¦                     ¦  ogenies. ¦      

   ¦    ¦  N ¦    ¦  (= Conemaugh       ¦                                                                                                                                                         part of     ¦                                 +      

   ¦    ¦  N ¦    +  Group)             ¦                                        ¦                         ¦                                         ¦                                         ¦  Piedmont    ¦                     ¦                  

   ¦    ¦  S ¦                          ¦                                                                                                                                                         province,   ¦                                        

   ¦    ¦  Y ¦    +  +------+           ¦                             +          ¦                         ¦                                         ¦                                         ¦  where they  ¦                     ¦                  

   ¦  C ¦  L ¦    ¦  ¦ PP2  ¦           ¦                +--------+   ¦                                                                                                                           are post-   ¦                                        

   ¦  A ¦  V ¦  M ¦  +------+           ¦                ¦uPz ¦ P ¦   ¦          ¦                         ¦                  +                      ¦                                         ¦  metamor-    ¦                     ¦                  

   ¦  R ¦  A ¦  I ¦  DES MOINESIAN      ¦      +------+  ¦----+---¦   ¦                                       +------+        ¦                                                                   phic; rare  ¦                                        

   ¦  B ¦  N ¦  D ¦  SERIES             ¦      ¦  PP  ¦  ¦uPzc¦   ¦   ¦          ¦                         ¦  ¦ uPze ¦        ¦                      ¦                                         ¦  in New      ¦                     ¦                  

   ¦  O ¦  I ¦  D ¦  (= Allegheny Group)¦      +------+  +--------+   ¦                                       +------+        ¦                                                                   England.    ¦                                        

   ¦  N ¦  A ¦  L ¦                     ¦      PENNSYL-  UPPER        ¦          ¦                         ¦  UPPER PALEOZOIC ¦                      ¦                                         ¦              ¦                     ¦                  

   ¦  I ¦  N ¦  E ¦  +------+           ¦      VANIAN    PALEOZOIC    ¦ Western                               EUGEOSYNCLINAL  ¦ Western                                                                       ¦                                         

 P ¦  F ¦    ¦    ¦  ¦ PP1  ¦           ¦                P, Permian   ¦ United   ¦                         ¦  DEPOSITS        ¦ United               ¦                                         ¦              ¦                     ¦                  

   ¦  E ¦    ¦    +  ¦------¦           ¦                separated in ¦ States.                               Permian sep-    ¦ States.                                                                       ¦                                         

 A ¦  R ¦    ¦    +  ¦ PP1a ¦           ¦                part; uPzc,  ¦          ¦                         ¦  arated in a few ¦                      ¦                                         ¦              ¦                     ¦                  

   ¦  O ¦    ¦    ¦  +------+           ¦                clastic wedge¦                                       places: see     ¦                                                                               ¦                                         

 L ¦  U ¦    ¦  L ¦  ATOKAN AND         ¦                facies in    ¦          ¦                         ¦  above.          ¦                      ¦                                         ¦              ¦                     ¦                   

   ¦  S ¦    ¦  O ¦  MORROWAN SERIES    ¦                Nevada and   ¦                                                       +                                                                               ¦                                         

 E ¦    ¦    ¦  W ¦  (= Pottsville      ¦                Idaho; Dia-  ¦          ¦                         ¦                                         ¦                                         ¦              ¦                     ¦                  

   ¦  S ¦    ¦  E ¦  Group)             ¦                mond Peak,   ¦                                                                                                                                       ¦                                        

 O ¦  Y ¦    ¦  R ¦  PP1a, Jackfork     ¦                Wood River,  ¦          ¦                         ¦                                         ¦                                         ¦              ¦                     ¦                  

   ¦  S ¦    ¦    ¦  Sandstone of Mor-  ¦                Milligen and ¦                                                                                                                                       ¦           +                            

 Z ¦  T ¦    ¦    ¦  rowan age in Ouach-¦                associated   ¦          ¦                         ¦                                         ¦                                         ¦              ¦ +------+  ¦         ¦                  

   ¦  E ¦    +    +  ita Mountains.     ¦                formations.  ¦                                                                                                                                       ¦ ¦ Pzmi ¦  ¦                            

 O ¦  M ¦                               ¦                             +          ¦                         ¦                                         ¦                                         ¦              ¦ +------+  ¦         ¦                  

   ¦    ¦    +    +  +------+           ¦                                                                                                                                                                     ¦ PALEOZOIC ¦                            

 I ¦    ¦    ¦    ¦  ¦  M3  ¦           ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦ MAFIC     ¦ Appala- ¦                  

   ¦    ¦  M ¦  U ¦  +------+           ¦                                                                                                                                                                     ¦ INTRU-    ¦ chian                      

 C ¦    ¦  I ¦  P ¦  CHESTERIAN SERIES  ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦ SIVES.    ¦ region. ¦                  

   ¦    ¦  S ¦  P ¦                     ¦                                                                                                                                                                     ¦ Of var-   ¦                           

   ¦    ¦  S ¦  E ¦  +------+           ¦    +------+                            ¦                         ¦                                         ¦                                         ¦              ¦ ious ages,¦         ¦                  

   ¦    ¦  I ¦  R ¦  ¦  M2  ¦           ¦    ¦  M   ¦                                                                                                                                                         ¦ not dif-  ¦                           

   ¦    ¦  S ¦    ¦  +------+           ¦    +------+                            ¦                         ¦                                         ¦                                         ¦              ¦ feren-    ¦         ¦             +    

   ¦    ¦  S ¦    +  MERAMECIAN SERIES  ¦    MISSISSIPPIAN                                                                                                                                                    ¦ tiated.   ¦            +------+   ¦    

   ¦    ¦  I ¦                          ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦           +         ¦  ¦  ms  ¦   ¦    

   ¦    ¦  P ¦  L +  +------+           ¦                                                                                                                                                                     ¦                        ¦------¦   ¦    

   ¦    ¦  P ¦  O ¦  ¦  M1  ¦           ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦                     ¦  ¦  m1  ¦   ¦    

   ¦    ¦  I ¦  W ¦  +------+           ¦                                                                                                                                                                     ¦                        ¦------¦   ¦     

   ¦    ¦  A ¦  E ¦  OSAGEAN AND        ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦                     ¦  ¦  m2  ¦   ¦

   ¦    ¦  N ¦  R ¦  KINDERHOOKIAN      ¦                                                                                                                                                                     ¦                        ¦------¦   ¦

   ¦    ¦    ¦    +  SERIES             ¦                                        ¦                         ¦                                         ¦                                         ¦              ¦                     ¦  ¦  m3  ¦   ¦

   ¦    +    +                          +                                                                                                                                                                     ¦                        ¦------¦   ¦

   ¦           --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --¦ --  --  --  -- --  --  -+  --  --  --  -- --  --  --  --  --  --  +- --  --  --  --  --  --  --  --  --  -- ¦--  --  --  --¦ --  --  --  --  --  +- ¦  m4  ¦ --¦ --  --  --

   ¦         +                          +                                                       +                                                                            +                                ¦                        +------+   ¦ P

   ¦         ¦       +------+           ¦                                        ¦  +------+    ¦          ¦                                         ¦            +------+   ¦                 ¦  +------+    ¦ Appalachian         ¦  METAMOR-   ¦ i

   ¦         ¦       ¦  D3  ¦           ¦                                           ¦ D3c  ¦    ¦                                                                 ¦  Dv  ¦   ¦                    ¦ Pzg2 ¦    ¦ region (New            PHIC       ¦ e

   ¦         ¦       +------+           ¦                                        ¦  +------+    ¦          ¦           +                             ¦            +------+   ¦                 ¦  +------+    ¦ England and         ¦  COMPLEXES  ¦ d

   ¦       D ¦       UPPER DEVONIAN     ¦                                           UPPER       ¦             +------+ ¦                                          DEVONIAN   ¦                    MIDDLE      ¦ Piedmont               Metamor-   ¦ m 

   ¦       E ¦                          ¦                                        ¦  DEVONIAN    ¦          ¦  ¦  De  ¦ ¦                             ¦            VOLCANIC   ¦                 ¦  PALEOZOIC   ¦ province),          ¦  phosed     ¦ o

   ¦       V ¦       +------+           ¦ +------+                                  CONTINENTAL ¦ New         +------+ ¦                                          ROCKS      ¦                    GRANITIC    ¦ rarely in              during     ¦ n  

   ¦       O ¦       ¦  D2  ¦           ¦ ¦  D   ¦                               ¦  DEPOSITS    ¦ York,    ¦  DEVONIAN ¦                             ¦                       ¦                 ¦  ROCKS       ¦ western             ¦  Phanerozoic¦ t

   ¦       N ¦       +------+           ¦ +------+                                              ¦ Pennsyl-    EUGEOSYN-¦            +                                        ¦                    About 350-  ¦ United                 orogenies. ¦

   ¦       I ¦       MIDDLE DEVONIAN    ¦ DEVONIAN                               ¦  +------+    ¦ vania,   ¦  CLINAL   ¦   +------+ ¦                ¦            +------+   ¦                 ¦  400 my. In  ¦ States.             ¦  Ages of    ¦ p

   ¦       A ¦                          ¦                                           ¦ D2c  ¦    ¦ and         DEPOSITS ¦   ¦ DSe  ¦ ¦                             ¦ DSv  ¦   ¦                    New Eng-    ¦                        original   ¦ r

   ¦       N ¦       +------+           ¦                                        ¦  +------+    ¦ Maine.   ¦           ¦   +------+ ¦                ¦            +------+   ¦ A               ¦  land, New   ¦                     ¦  rocks un-  ¦ o

   ¦         ¦       ¦  D1  ¦           ¦                                           MIDDLE      ¦                      ¦   DEVONIAN ¦                             DEVONIAN   ¦ p                  Hampshire   ¦                        certain; in¦ v

   ¦         ¦       +------+           ¦                                        ¦  DEVONIAN    ¦          ¦           ¦   AND      ¦                ¦            AND        ¦ p               ¦  Plutonic    ¦                     ¦  Piedmont   ¦ i

   ¦         +       LOWER DEVONIAN     ¦           +------+                        CONTINENTAL ¦                      ¦   SILURIAN ¦                             SILURIAN   ¦ a                  Series and  ¦                        province   ¦ n

   ¦                                    ¦           ¦  DS  ¦                     ¦  DEPOSITS    ¦          ¦           ¦   EUGEOSYN-¦                ¦            VOLCANIC   ¦ l               ¦  others,     ¦                     ¦  may be     ¦ c

   ¦         +       +------+           ¦           +------+                                    +                      ¦   CLINAL   ¦                             ROCKS      ¦ a                  related to  ¦                        largely    ¦ e

   ¦         ¦       ¦  S3  ¦           ¦           DEVONIAN                     ¦                         ¦           ¦   DEPOSITS ¦                ¦                       ¦ c               ¦  Acadian     ¦                     ¦  Precambrian¦ 

   ¦         ¦       +------+           ¦           AND SILURIAN                                                       ¦            ¦ N                                      ¦ h                  orogeny; in ¦                        Z, but with¦ a

   ¦         ¦       UPPER SILURIAN     ¦                                        ¦                         ¦           ¦            ¦ e              ¦                       ¦ i               ¦  Piedmont    ¦                     ¦  some lower ¦ n

   ¦       S ¦       (Cayugan)          ¦                                                                              ¦            ¦ w                                      ¦ a                  province,   ¦                        Paleozoic; ¦ d

   ¦       I ¦                          ¦                                        ¦                         ¦           ¦            ¦                ¦                       ¦ n               ¦  synmeta-    ¦                     ¦  in northern¦ 

   ¦       L ¦       +------+           ¦ +------+                                                            +------+ ¦            ¦ E                           +------+   ¦                    morphic.    ¦                        Washington ¦ n

   ¦       U ¦       ¦  S2  ¦           ¦ ¦  S   ¦                               ¦                         ¦  ¦  Se  ¦ ¦            ¦ n              ¦            ¦  Sv  ¦   ¦ r               ¦              ¦                     ¦  may be     ¦ o

   ¦       R ¦       +------+           ¦ +------+                                                            +------+ ¦            ¦ g                           +------+   ¦ e                              ¦                        largely    ¦ r

   ¦       I ¦       MIDDLE SILURIAN    ¦ SILURIAN                               ¦                         ¦  SILURIAN ¦            ¦ l              ¦            SILURIAN   ¦ g               ¦              ¦                     ¦  lower to   ¦ t

   ¦       A ¦       (Niagaran)         ¦                                                                     EUGEOSYN-¦            ¦ a                           VOLCANIC   ¦ i                              ¦                        upper      ¦ h

   ¦       N ¦                          ¦                                        ¦                         ¦  CLINAL   ¦            ¦ n              ¦            ROCKS      ¦ o               ¦              ¦                     ¦  Paleozoic. ¦ e  

   ¦         ¦       +------+           ¦                                                                     DEPOSITS ¦            ¦ d                                      ¦ n                              ¦                        ms, schist ¦ r

   ¦         ¦       ¦  S1  ¦           ¦                             +          ¦                         ¦           ¦            ¦                ¦                       ¦                 ¦              ¦                     ¦  and phyl-  ¦ n

   ¦         ¦       +------+           ¦             +------+        ¦                                                ¦            ¦   +------+ + W                         ¦                                ¦                        lite; m1,  ¦   

   ¦         ¦       LOWER SILURIAN     ¦ Eastern     ¦ lPz  ¦        ¦          ¦                         ¦           ¦  +------+  ¦   ¦ lPze ¦ ¦ e ¦                       ¦                 ¦              ¦                     ¦  felsic par-¦ W

   ¦         +       (Alexandrian)      ¦ United      ¦  +---¦        ¦ Western                                        ¦  ¦ SOe  ¦  ¦   +------+ ¦ s                         ¦                                ¦                        agneiss and¦ a

   ¦                                    ¦ States.     ¦  ¦ C ¦        ¦ United   ¦                         ¦           ¦  +------+  ¦   LOWER    ¦ t ¦                       ¦                 ¦              ¦                     ¦  schist; m2,¦ s

   ¦         +       +------+           ¦             +------+        ¦ States                                         ¦  SILURIAN  ¦   PALEOZOIC¦ e                         ¦                                ¦                        mafic para-¦ h

   ¦         ¦       ¦  O3  ¦           ¦             LOWER PALEOZOIC ¦ and      ¦                         ¦           ¦  AND       ¦   EUGEOSYN-¦ r ¦                       ¦                 ¦              ¦                     ¦  gneiss (=  ¦ i

   ¦         ¦       +------+           ¦             C, Cambrian     ¦ Piedmont                                       ¦  ORDOVICIAN¦   CLINAL   ¦ n                         ¦                                ¦                        hornblend- ¦ n

   ¦         ¦       UPPER ORDOVICIAN   ¦             separated in    ¦ province.¦                         ¦           ¦  EUGEOSYN- ¦   DEPOSITS ¦   ¦                       ¦                 ¦              ¦                     ¦  ite and am-¦ g

   ¦         ¦       (Cincinnatian)     ¦             part.           ¦                                                ¦  CLINAL    ¦            ¦ U                         ¦                                ¦                        phibolite);¦ t

   ¦         ¦                          ¦                             +          ¦                         ¦           ¦  DEPOSITS  ¦            + S ¦                       ¦                 ¦              ¦                     ¦  m3, migma- ¦ o

   ¦         ¦       +------+           ¦ +------+                                                            +------+ ¦            +                             +------+   ¦                                ¦                        tite; m4,  ¦ n

   ¦         ¦       ¦  O2  ¦           ¦ ¦  O   ¦                               ¦                         ¦  ¦  Oe  ¦ ¦                             ¦            ¦  Ov  ¦   ¦                 ¦              ¦                     ¦  felsic or- ¦ 

   ¦         ¦       +------+           ¦ +------+                                                            +------+ ¦                                          +------+   ¦                                ¦                        thogneiss  ¦

   ¦       O ¦       MIDDLE ORDOVICIAN  ¦ ORDOVICIAN                             ¦                         ¦  ORDO-    ¦ Appalachian                 ¦            ORDOVICIAN ¦                 ¦  +------+    ¦                     ¦  (= granite ¦ 

   ¦       R ¦       (Mohawkian)        ¦                                                                     VICIAN   ¦ region.                                  VOLCANIC   ¦                    ¦ Pzg1 ¦    ¦                        gneiss).   ¦ 

   ¦       D ¦       Upper Ordovician   ¦                                        ¦                         ¦  EUGEOSYN                             ¦            ROCKS      ¦                 ¦  +------+    ¦                     ¦             +

   ¦       O ¦       included in        ¦                                                                     CLINAL   ¦                                                     ¦                    LOWER       ¦                                       

   ¦       V ¦       places.            ¦                                        ¦                         ¦  DEPOSITS ¦                             ¦                       ¦                 ¦  PALEOZOIC   ¦                     ¦   

   ¦       I ¦                          ¦                                                                              ¦                                                     ¦                    GRANITIC    ¦                          

   ¦       C ¦       +--------+         ¦                                        ¦                         ¦           ¦                             ¦                       ¦                 ¦  ROCKS       ¦                     ¦   

   ¦       I ¦       ¦   ¦O1b ¦         ¦                                                                              ¦                                                     ¦                    About 400-500 my.  In New          

   ¦       A ¦       ¦O1 +----¦         ¦                                        ¦                         ¦           ¦                             ¦                       ¦                 ¦  England, Highlandcroft and        ¦

   ¦       N ¦       ¦   ¦O1a ¦         ¦                                                                              ¦                                                     ¦                    Oliverian Plutonic Series,         

   ¦         ¦       +--------+         ¦                                        ¦                         ¦           ¦                             ¦                       ¦                 ¦  related to Taconian               ¦

   ¦         ¦       LOWER ORDOVICIAN   ¦                                                                              ¦                                                     ¦                    orogeny; in Piedmont                

   ¦         ¦       (Canadian)         ¦                                        ¦                         ¦           ¦                             ¦                       ¦                 ¦  province, premetamorphic.         ¦

   ¦         ¦       In Ozark Plateau   ¦                                                                              ¦                                                     ¦                                ¦                           

   ¦         ¦       of Missouri, div-  ¦                                        ¦                         ¦           ¦                             ¦                       ¦                 ¦              +                     ¦  

   ¦         ¦       ided into O1a and  ¦                        +                                                     ¦                                                     ¦                                                            

   ¦         ¦       b at base of       ¦      +------+          ¦ New           ¦                         ¦           ¦                             ¦                       ¦                 ¦                                    ¦   

   ¦         ¦       Jefferson City     ¦      ¦  OC  ¦          ¦ York                                                ¦                                                     ¦                                                           

   ¦         +       Dolomite.          +      +------+          ¦ and           ¦                         ¦           ¦                             ¦                       ¦                 ¦                                    ¦   

   ¦                                           LOWER ORDOVICIAN  ¦ western                                    +------+ ¦                                          +------+   ¦                    +------+   +                         

   ¦         +       +------+                  AND CAMBRIAN      ¦ New           ¦                         ¦  ¦  Ce  ¦ ¦                             ¦            ¦  Cv  ¦   ¦                 ¦  ¦  Cg  ¦   ¦                      ¦  

   ¦         ¦       ¦  C   ¦                  CARBONATE ROCKS   ¦ England.                                   +------+ ¦                                          +------+   ¦                    +------+   ¦ Oklahoma                     

   ¦         ¦       ¦------¦                                    +               ¦                         ¦  CAMBRIAN ¦                             ¦            CAMBRIAN   ¦                 ¦  CAMBRIAN   ¦ and                  ¦  

   ¦       C ¦       ¦  Cq  ¦                                                                                 EUGEOSYN-¦                                          VOLCANIC   ¦                    GRANITIC   ¦ Colorado.                    

   ¦       A ¦       +------+                                                    ¦                         ¦  CLINAL   ¦                             ¦            ROCKS      ¦                 ¦  ROCKS      ¦                      ¦  

   ¦       M ¦       CAMBRIAN                                                                                 DEPOSITS ¦                                                     +                    About 500  ¦                         

   ¦       B ¦       Cq, basal Lower Cambrian                                    ¦                         ¦           +                             ¦                                         ¦  my.        +                      ¦      

   ¦       R ¦       clastic rocks, Chilhowee                                                                                                                                                                                              

   ¦       I ¦       Group and equivalents,                                      ¦                         ¦                                         ¦                                         ¦                                    ¦    

   ¦       A ¦       shown separately in                                                                                                                                                                                                     

   ¦       N ¦       parts of Appalachian                                        ¦                         ¦                                         ¦                                         ¦                                    ¦    

   ¦         ¦       region.                                                                                                                                                                                                                    

   +         +                                                                   ¦                         ¦                                         ¦                                         ¦                                    ¦  

     --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  -- --  --  --  --  --  --  --  --  --  --  --  -- --  --  --  -- --  --  --  --   --  --  --  --  --  --  --  --  --  --

   ¦            +                                                                ¦                         ¦                                         ¦                                         ¦                                    ¦                   

   ¦            ¦        +------+                                                                                                                                +------+                         +------+                                 

   ¦            ¦        ¦  Z   ¦                                                ¦                         ¦                                         ¦           ¦  Zv  ¦                      ¦  ¦  Zg  ¦                          ¦      

   ¦            ¦        +------+                                                                                                                                +------+                         +------+                                 

   ¦     800    ¦        Z SEDIMENTARY ROCKS                                     ¦                         ¦                                         ¦           Z VOLCANIC                    ¦  Z GRANITIC                        ¦           

   ¦     my to  ¦        Includes (among other units): In Appalachian region,                                                                                    ROCKS                            ROCKS                                   

   ¦     begin- ¦        Ocoee Supergroup and Lynchburg Formation including      ¦                         ¦                                         ¦           In Appalachian                ¦  About 650-                        ¦                      

   ¦  Z  ning   ¦        rocks older than 800 my: in Lake Superior region,                                                                                       region, Catoctin                 800 my.                                     

   ¦     of Cam-¦        Bayfield Group, Jacobsville and Hinckley Sandstones;    ¦                         ¦                                         ¦           Greenstone and                ¦                                    ¦                     

   ¦     brian  ¦        in northwestern United States, Windermere Group; in                                                                                     related units,                                                             

   ¦            ¦        Great Basin, Noonday, Johnnie and other formations; in  ¦                         ¦                                         ¦           including                     ¦                                    ¦         

   ¦            ¦        Grand Canyon, Chuar Group of Grand Canyon Supergroup.                                                                                   rocks older                                                              

   ¦            +                                                                ¦                         ¦                                         ¦           than 800 my.                  ¦                                    ¦         

   ¦               --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --   --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --

   ¦            +    +                   +                                       ¦                         ¦                                         ¦                                         ¦                         +          ¦                  

 P ¦            ¦    ¦   +------+        ¦           +------+                                                                                                    +------+                         +------+     +------+  ¦             +------+        

   ¦            ¦  B ¦   ¦  Y3  ¦        ¦           ¦  Y   ¦                    ¦                         ¦                                         ¦           ¦  Yv  ¦                      ¦  ¦  Yg2 ¦     ¦  Ys  ¦  ¦          ¦  ¦  Ym  ¦      

 R ¦            ¦  E ¦   +------+        ¦           +------+                                                                                                    +------+                         +------+     +------+  ¦ Adi-        +------+      

   ¦       1600 ¦  L ¦   MISSOULA GROUP  ¦ North-    Y SEDIMENTARY ROCKS         ¦                         ¦                                         ¦           Y VOLCANIC                    ¦  YOUNGER Y    SYENITE   ¦ rondack  ¦  PARAGNEISS     

 E ¦  Y    to   ¦  T ¦                   ¦ western   Includes (among other                                                                                       ROCKS                            GRANITIC               ¦ Moun-       AND SCHIST    

   ¦       800  ¦    ¦   +------+        ¦ Montana   units): In Lake Superior    ¦                         ¦                                         ¦           Mafic lavas in                ¦  ROCKS                  ¦ tains    ¦       

 C ¦       my   ¦  S ¦   ¦  Y2  ¦        ¦ and       region, Oronto Group of                                                                                     Keweenawan                       About 1000             ¦ and               

   ¦            ¦  U ¦   +------+        ¦ northern  Keweenawan Supergroup, and  ¦                         ¦                                         ¦           Supergroup.                   ¦  my.          +------+  ¦ else-    ¦       

 A ¦            ¦  P ¦   WALLACE, SIYEH, ¦ Idaho.    Sioux Quartzite; in                                                                                         Felsic                                        ¦  Ya  ¦  ¦ where.                    

   ¦            ¦  E ¦   AND HELENA      ¦           northwestern United States, ¦                         ¦                                         ¦           volcanic                      ¦               +------+  ¦          ¦                

 M ¦            ¦  R ¦   FORMATIONS      ¦           undivided Belt Supergroup;                                                                                  rocks in                                      ANORTHO-  ¦                           

   ¦            ¦  G ¦                   ¦           in Utah, Big Cottonwood     ¦                         ¦                                         ¦           Missouri.                     ¦  +------+     SITE      +          ¦  +------+        

 B ¦            ¦  R ¦   +------+        ¦           Group; in southwestern                                                                                                                       ¦  Yg1 ¦                             ¦  Ygn ¦       

   ¦            ¦  O ¦   ¦  Y1  ¦        ¦           United States, Pahrump      ¦                         ¦                                         ¦                                         ¦  +------+     +------+  +          ¦  +------+       

 R ¦            ¦  U ¦   +------+        ¦           Group, Unkar Group of Grand                                                                                                                  OLDER Y      ¦  Ymi ¦  ¦             ORTHOGNEISS    

   ¦            ¦  P ¦   RAVALLI GROUP   ¦           Canyon Supergroup, Apache   ¦                         ¦                                         ¦                                         ¦  GRANITIC     +------+  ¦ Lake     ¦          

 I ¦            ¦    ¦   AND PRICHARD    ¦           Group and Troy Quartzite;                                                                                                                    ROCKS        MAFIC     ¦ Superior              

   ¦            ¦    ¦   FORMATION       ¦           in northern Adirondack      ¦                         ¦                                         ¦                                         ¦  About 1300-  INTRU-    ¦ region.  ¦          

 A ¦            ¦    ¦                   ¦           Mountains, Grenville Group.                                                                                                                  1400 my.     SIVES     ¦                       

   ¦            ¦    ¦                   ¦                                       ¦                         ¦                                         ¦                                         ¦               Includes  ¦                       

 N ¦            ¦    ¦                   ¦                                                                                                                                                                     Duluth    ¦                       

   ¦            ¦    ¦                   ¦                                       ¦                         ¦                                         ¦                                         ¦               Gabbro    ¦                       

   ¦            ¦    +                   +                                                                                                                                                                     Complex.  ¦                       

   ¦               --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --¦ --  --  --  --  --  --  +-  --  --  --  --  --  --  --  --  --  --¦ --  --  --  --  --  --  --  --  --  --  +-  --  --  --  --  --  --¦ --  --  -+  --  --  --  --  --  --

   ¦            +                                                                                                                                                                                                                                 

   ¦            ¦        +------+                                                ¦                         ¦                                         ¦           +------+                      ¦  +------+                          ¦  +------+       

   ¦            ¦        ¦  X   ¦                                                                                                                                ¦  Xv  ¦                         ¦  Xg  ¦                             ¦  Xm  ¦          

   ¦            ¦        +------+                                                ¦                         ¦                                         ¦           +------+                      ¦  +------+                          ¦  +------+         

   ¦     2500   ¦        X METASEDIMENTARY ROCKS                                                                                                                 X VOLCANIC                       X GRANITIC                           ORTHOGNEISS   

   ¦  X  to     ¦        Includes (among other units): In Lake Superior region,  ¦                         ¦                                         ¦           ROCKS                         ¦  ROCKS                             ¦  AND    

   ¦     1600   ¦        Animikie Group and Marquette Range Supergroup; in South                                                                                 Associated                       About 1700-                          PARAGNEISS    

   ¦     my     ¦        Dakota and Wyoming, units in Black Hills and Medicine   ¦                         ¦                                         ¦           with X sed-                   ¦  1800 my.                          ¦  Extensive in western

   ¦            ¦        Bow Mountains; in Arizona, Mazatzal Quartzite, Yavapai                                                                                  imentary rocks                                                        and southwestern

   ¦            ¦        Series, Pinal Schist, and metavolcanic formations.      ¦                         ¦                                         ¦           in northern                   ¦                                    ¦  United States; of

   ¦            ¦        Iron formations of Lake Superior region separately                                                                                      Wisconsin.                                                            varied compositions

   ¦            +        shown in red.                                           ¦                         ¦                                         ¦                                         ¦                                    ¦  and origins. 

   ¦               --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --   --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --  --

   ¦            +                                                                ¦                         ¦                                         ¦                                         ¦                                    ¦       

   ¦            ¦        +------+                                                                                                                                +------+                         +------+     +------+                +------+          

   ¦            ¦        ¦  W   ¦                                                ¦                         ¦                                         ¦           ¦  Wv  ¦                      ¦  ¦  Wg  ¦     ¦  Wmi ¦             ¦  ¦  Wgn ¦            

   ¦            ¦        +------+                                                                                                                                +------+                         +------+     +------+                +------+            

   ¦     2500   ¦        W METASEDIMENTARY ROCKS                                 ¦                         ¦                                         ¦           W VOLCANIC                    ¦  W GRANITIC   W MAFIC              ¦  ORTHOGNEISS     

   ¦  W  my and ¦        Includes (among other units): In                                                                                                        ROCKS                            ROCKS        INTRUSIVES              AND     

   ¦     older  ¦        Lake Superior region, Knife Lake                        ¦                         ¦                                         ¦           Ely Greenstone                ¦  2500 my      Stillwater           ¦  PARAGNEISS     

   ¦            ¦        Group; in Montana, Cherry Creek                                                                                                         and other units                  and          Complex of                   

   ¦            ¦        Group; various units in Wyoming.                        ¦                         ¦                                         ¦           in Lake Superior              ¦  older.       Montana.             ¦       

   ¦            ¦                                                                                                                                                region.                                                              

   ¦            ¦                                                                ¦                         ¦                                         ¦                                         ¦                                    ¦     

   +            +                                                                                                                                                                                    

 

 

 

+-------------------------------------------------------------------------------------------------------------------------------------------+

¦                                                                                                                                           ¦

¦        GREAT             NORTHERN             NEW              CENTRAL             OKLA-            KANSAS &           WEST TEXAS         ¦

¦        BASIN             ARIZONA             MEXICO             TEXAS              HOMA             NEBRASKA            STANDARD          ¦

¦                                                                                                                                           ¦

¦                                           +----------+-------+----------+-------+----------+--------------------------+----------+        ¦

¦                                           ¦P4        ¦       ¦P4        ¦       ¦P4        ¦                          ¦P4        ¦        ¦

¦                                           ¦RUSTLER FM¦       ¦ QUARTER- ¦       ¦ QUARTER- ¦                          ¦          ¦        ¦

¦                                           ¦SALADO FM ¦       ¦MASTER FM ¦       ¦  MASTER  ¦                          ¦  OCHOAN  ¦        ¦

¦                                           ¦CASTILE FM¦       ¦Clayton-  ¦       ¦    FM    ¦                          ¦  SERIES  ¦        ¦

¦                                           ¦          ¦       ¦ville Dol ¦       ¦          ¦                          ¦          ¦        ¦

¦     +----------+- - - - - - - - - - - - - ¦----------¦-------¦----------¦-------¦----------¦-------+----------+-------¦----------¦        ¦

¦     ¦P         ¦                          ¦P3b       ¦       ¦P3b       ¦       ¦P3b       ¦       ¦P3b       ¦       ¦P3        ¦        ¦

¦     ¦          ¦                          ¦          ¦       ¦  CLOUD   ¦       ¦  CLOUD   ¦       ¦          ¦       ¦          ¦        ¦

¦     ¦          ¦                          ¦ ARTESIA  ¦       ¦ CHIEF FM ¦       ¦ CHIEF FM ¦       ¦WHITEHORSE¦       ¦          ¦        ¦

¦     ¦          ¦                          ¦    GP    ¦       ¦WHITEHORSE¦       ¦WHITEHORSE¦       ¦    GP    ¦       ¦  GUADA-  ¦        ¦

¦     ¦          ¦                          ¦          ¦       ¦    GP    ¦       ¦    GP    ¦       ¦          ¦       ¦  LUPIAN  ¦        ¦

¦     ¦          ¦                         /¦----------¦\------¦----------¦-------¦----------¦-------¦----------¦       ¦          ¦        ¦

¦     ¦          ¦                        / ¦P2b       ¦ \     ¦P3a       ¦       ¦P3a       ¦       ¦P3a       ¦       ¦          ¦        ¦

¦     ¦ PERMIAN  ¦                       /  ¦          ¦  \    ¦BLAINE FM ¦       ¦          ¦       ¦          ¦       ¦  SERIES  ¦        ¦

¦     ¦          ¦                      /   ¦   SAN    ¦   \   ¦   SAN    ¦       ¦ EL RENO  ¦       ¦ VARIOUS  ¦       ¦          ¦        ¦

¦     ¦          ¦                     /    ¦          ¦    \  ¦  ANGELO  ¦       ¦    GP    ¦       ¦  UNITS   ¦       ¦          ¦        ¦

¦     ¦          ¦                    /     ¦  ANDRES  ¦     \ ¦    SS    ¦       ¦          ¦       ¦          ¦       ¦          ¦        ¦

¦     ¦          ¦       +----------+/ - - -¦          ¦- - - \¦----------¦-------¦----------¦-------¦----------¦-------¦----------¦        ¦

¦     ¦          ¦       ¦P2b       ¦       ¦    LS    ¦       ¦P2b       ¦       ¦P2b       ¦       ¦P2b       ¦       ¦P2        ¦        ¦

¦     ¦          ¦       ¦ KAIBAB   ¦       ¦          ¦       ¦CLEAR FORK¦       ¦          ¦       ¦NIPPEWALLA¦       ¦          ¦        ¦

¦     ¦          ¦       ¦    LS    ¦       ¦          ¦       ¦    GP    ¦       ¦ HENNESSY ¦       ¦    GP    ¦       ¦          ¦        ¦

¦     ¦          ¦       ¦ TOROWEAP ¦       ¦          ¦       ¦ LEUDERS  ¦       ¦   SH     ¦       ¦  Stone   ¦       ¦  LEON-   ¦        ¦

¦     ¦          ¦       ¦    FM    ¦       ¦          ¦       ¦    LS    ¦       ¦          ¦       ¦Corral Fm ¦       ¦  ARDIAN  ¦        ¦

¦     ¦          ¦       ¦----------¦-------¦----------¦-------¦----------¦-------¦----------¦-------¦----------¦       ¦          ¦        ¦

¦     ¦UNDIVIDED ¦       ¦P2a       ¦       ¦P2a       ¦       ¦P2a       ¦       ¦P2a       ¦       ¦P2a       ¦       ¦          ¦        ¦

¦     ¦          ¦       ¦ COCONINO ¦       ¦ GLORIETA ¦       ¦WICHITA GP¦       ¦          ¦       ¦          ¦       ¦  SERIES  ¦        ¦

¦     ¦          ¦       ¦    SS    ¦       ¦    SS    ¦       ¦          ¦       ¦  GARBER  ¦       ¦ VARIOUS  ¦       ¦          ¦        ¦

¦     ¦          ¦       ¦  HERMIT  ¦       ¦ YESO FM  ¦       ¦ Coleman  ¦       ¦    SS    ¦       ¦  UNITS   ¦       ¦          ¦        ¦

¦     ¦          ¦       ¦    SH    ¦       ¦          ¦       ¦ Jct. Mbr ¦       ¦          ¦       ¦          ¦       ¦          ¦        ¦

¦     ¦          ¦       ¦          ¦- - - /¦----------¦-------¦----------¦-------¦----------¦-------¦----------¦-------¦----------¦        ¦

¦     ¦          ¦       ¦  SUPAI   ¦     / ¦P1c       ¦       ¦P1        ¦       ¦P1        ¦       ¦P1        ¦       ¦P1        ¦        ¦

¦     ¦          ¦       ¦    FM    ¦    /  ¦          ¦       ¦ CISCO GP ¦       ¦WELLINGTON¦       ¦          ¦       ¦   WOLF-  ¦        ¦

¦     ¦          ¦       ¦          ¦   /   ¦  ABO SS  ¦       ¦  (part)  ¦       ¦    FM    ¦       ¦ VARIOUS  ¦       ¦  CAMPIAN ¦        ¦

¦     ¦          ¦       ¦          ¦  /    ¦          ¦       ¦Saddle Cr.¦       ¦   ETC.   ¦       ¦  UNITS   ¦       ¦  SERIES  ¦        ¦

¦     ¦          ¦       ¦          ¦ /     ¦          ¦       ¦   Mbr    ¦       ¦          ¦       ¦          ¦       ¦          ¦        ¦

¦     +----------+       +----------+/      +----------+-------+----------+-------+----------+-------+----------+-------+----------+        ¦

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¦                                                                                                                                           ¦

¦                                         DIAGRAM OF PERMIAN STRATA, NORTHERN ARIZONA TO MIDCONTINENT                                       ¦

¦                                                      [SHOWING UNITS USED ON U.S. MAP]                                                     ¦

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