142  INDEX    TO    PUBLICATIONS    OF    U.    S.    GEOL.    SUKVEY.     [bull.  177 
Aporhyolite,  thin  section  of,  from  Michigan,  Crystal  Falls  district,  showing 
perlitic  parting Mon  xxxvi,  pp  274-275 
thin  section  of,  from  Minnesota,  Lake  Superior Bull  150,  pp  348-349 
from  Pennsylvania,  South  Mountain  (amygdaloidal) Bull  136, 
pp  118-119,  120-121 
South  Mountain,  showing  altered  and  unaltered  spherulites Bull  136, 
pp  110-111,  112-113 
showing  altered  spherulites Bull  150,  pp  346-347 
showing  axiolites Bull  136,  pp  108-109 
showing  flow  structure  and  chain  spherulites..  Bull  136,  pp  102-103 
showing  perlitic  parting Bull  136,  pp  106-107, 108-109 
showing  perlitic  spherulitic  and  lithophysal  structures Bull 
150,  pp  348-349 
showing  rhyolitic  structure Bull  136,  pp  114-115, 116-117 
Aporhyolite  breccia,  thin  section  of,  from  Michigan,  Crystal  Falls Mon 
xxxvi,  pp  276-277 
Aporliyolite-porphyries,    analyses    of,    from    California,    Downieville    quad- 
rangle  Ann  17,  i,  p  647 
Aporhyolite-porphyry  of  Michigan,  Crystal  Falls  district Ann  19, 
in,  p  51;  Mon  xxxvi,  p  87 
Aporrhaidse  from  Chico-Tejon  series  of  California Bull  51,  pp  19-20 
from  Colorado  formation Bull  106,  pp  143-146 
from  Cretaceous  of  Pacific  coast Bull  133,  p  72 
Appalachian  coal  field,  extent  of Ann  14,  n,  pp  573-574 
Appalachian  crystalline  belt,  igneous  granites  in,  distribution  and  relative  ages 
of Ann  15,  pp  666-670 
Appalachian  group,  geologic  name  proposed Bull  80,  p  60 
Appalachian  Mountain  region,  structure  of Bull  111,  pp  19-27 
Appalachian  Mountains  and  Valley,  brief  description  of Ann  19,  n,  pp  12, 15 
Appalachian  oil  field Ann  21,  vi  cont,  pp  29,  62-88 
Appalachian  province,  geologic  history  of GF  59,  p  2 
structure  of GF  61,  p  5 
subdivisions,  altitude,  drainage,  rocks,  etc.,  of GF  4,  pp  1,3; 
GF  8,  pp  1,  2-3;  GF  10,  pp  1,  3-4;  GF  12,  pp  1,  3;  GF  14, 
pp  1,  3;  GF  16,  pp  1,  5;  GF  19,  pp  1,  2-3;  GF  20,  pp  1,  3; 
GF  21,  pp  1,  2-3;  GF  22,  p  1;  GF  25,  pp  1,4;  GF  26,  pp 
1,  3-4;  GF  27,ppl,  3-4;  GF  28,  pp  1,  4;  GF  32,  pp  1,  4; 
GF33,  pp  1,  3;  GF  34,  pp  1,  3;  GF  35,  pp  1,  3;  GF40,  pp 
1,  3;  GF  44,  pp  1,  4;  GF  59,  p  1;  GF  61,  p  1;  GF  69,  p  1 
subdivisions  of  southern Ann  19,  n,  pp  11-13 
Appalachian  ridges,  examples  of TF  2,  p  8 
Appalachian  structure,  mechanics  of Ann  13,  n,  pp  211-281 
Appalachian  type  of  structure  in  Catoctin  belt Ann  14,  n,  pp  358-366 
Appalachians,  Cambrian  and  pre-Cambrian  rocks  of Bull  86,  p.  487 
gold  fields  of  southern,  geography,  history,  geology,  etc.,  of Ann  16, 
in,  pp  251-331 
Appomattox  or  Lafayette  formation.     (See  Lafayette  formation.) 
Appomattox  River,  profile  of WS  44,  p  23 
Appropriations  for  the  United  States  Geological  Survey Ann  1, 
p  15;  Ann  3,  p  xvii;  Ann  5,  p  xxxvi;  Ann  6,  p  xxviii;  Ann 
7,  p  42;  Ann  8,  i,  pp.  10-11,  92,  257;  Ann  9,  p  152;  Ann 
10,  i,  pp  80,  252;  Ann  11,  i,  pp  24-25,  140;  Ann  12,  i,  pp  18, 
210;  Ann  13,  i,  pp56, 185;  Annl4,  i,  pp  11-12,  61,  278;  Annl5, 
i,  pp  9-10, 108,  212;  Ann  16,  i,  pp  9-10,  89;  Ann  17,  i,  pp  14- 
15, 121;  Ann  18,  i,  pp  16-17, 130;  Ann  19,  i,  pp  25-26, 142-143; 
Ann  20,  i,  pp  25-28,  159-160;  Ann  21,  i,  pp  59-60,  186-187 
