ILLUSTRATIONS. 
Page. 
Plate  I.  Geologic  map  of  Hahns  Peak  and  vicinity,  Colorado,  showing  distribution 
of  rock  formations  and  placer  ground. ' 28 
II.  Hahns  Peak  and  vicinity,  Colorado 30 
III.  Map  showing  the  distribution  of  the  productive  copper  mines  of  the  United 
States 94 
IV.  Map  of  the  St.  Joe  River  district,  Idaho 130 
V.  Map  of  the  Warrior  coal  basin  in  the  Birmingham  quadrangle,  Alabama. .       212 
VI.  Map  of  Yampa  coal  field ,  Routt  County,  Colorado 226 
VII.  Reconnaissance  map  of  part  of  Durango-Gallup  coal  field,  showing  out- 
crops of  coal-bearing  rocks 242 
VIII.  Sketch  map  of  pari  of  Sanpete  Valley,  Utah,  showing  sections  across  the 
Wales  and  Sterling  coal  beds. 280 
IX.  Map  of  Book  Cliffs  coal  field,  west  of  Green  River,  Utah,  showing  outcrops 
of  coal-bearing  rocks. 290 
X.  Map  of  coal  fields  of  southern  Uinta  County,  Wyoming 336 
XI.  Geologic  map  of  southern  Uinta  County,  Wyoming,  showing  economic 
data  relating  to  oil,  underground  water,  and  copper 342 
XII.  A,  Cross  section  along  line  AA,  Pis.  X  and  XI,  showing  geologic  relations 
of  oil  springs  at  Billiard  and  of  wells  in  the  Spring  Valley  region;  B, 
cross  section  along  line  BB,  Pis.  X  and  XI,  showing  geologic  relations  of 
coal  beds,  and  oil  springs  and  wells  in  the  fossil  region 350 
XIII.  Map  showing  clay-producing  localities  of  western  Tennessee  and    Ken- 
tucky         418 
Fig.  1.  Cross  section  through  Hahns  Peak  and  Farwell  Mountain 29 
2.  Outline  map  of  northern  Idaho  and  northwestern  Montana 42 
3.  Sketch  map  of  southwestern  Nevada  and  eastern  California,  showing  loca- 
tion of  mining  camps 54 
4.  Map  of  New  Mexico 75 
5.  Diagram  showing  production   and  prices  of   copper  in  the    United    States 
from  1893  to  1905 94 
6.  Map  showing  location  of  St.  Joe  River  basin 1 30 
7.  Geologic  map  of  the  Franklin  Mountains,  Texas 147 
8.  Generalized  section  at  Iron  Gate,  Va 185 
9.  Theoretical  section  from  the  Stone  Canyon  coal  mine,  Monterey  County. 
Cal.,  northward  to  the  main  ridge,  showing  relation  of  Upper  Miocene  beds 
to  the  coal-bearing  formation. 224 
10.  Sketch  map  of  northeastern  Kentucky  and  portions  of  adjacent  States 260 
11.  Sketch  map  of  southern  Clearfield  and  parts  of  Indiana  and  Jefferson  coun- 
ties, Pa 272 
12.  Map  of  the  Salt  Lake  oil  field,  7  miles  west  of  Los  Angeles,  Cal 358 
13.  Map  showing  distribution  of  limestone  and  locations  of  quarries  in  vicinity 
of  Rockport,  Me 393 
14.  Map  showing  distribution  of  limestone  and  locations  of  quarries  in  vicinity 
of  Rockland  and  Thomaston,  Me 394 
15.  Diagrammatic  geologic  section  across  the  principal  limestone  belt,  south- 
west of  Rockland ,  Me. 307 
16.  Gypsum  measures  of  the  Uncompahgre  region 401 
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