630  INDEX    TO    PUBLICATIONS    OF    U.    S.    GEOL.    SURVEY,     [bull.  177. 
Potomac  clays,  description  of MR  1891,  p  492 
Potomac  coal  field  of  West  Virginia Ann  14,  n,  pp  573-588 
Potomac  formation,  comparison  of,  with  Wealden  of  England.. Ann  16,  i,  pp 471-500 
fossil  wood  and  lignite  of Bull  56 
geologic  position  of Bull  82,  p  250;  Bull  145,  pp  142-147 
Hay  Creek  coal  field,  Black  Hills,  compared  with Ann  19,  n,  pp  570-579 
in  District  of  Columbia GF  70,  pp  3-4 
in  Maryland Ann  7,  pp  546,  613-616; 
Bull  138,  p  125;  GF  13,  p  4;  GF  23,  p  3;  GF  70,  pp  3-4 
in  New  Jersey Bull  82,  p  215 
in  North  Carolina Ann  10,  p  174;  Bull  82,  p  91 
in  Pennsylvania Bull  84,  p  45 
in  South  Carolina Bull  138,  p  208 
in  Virginia Bull  82,  pp  90-91;  Bull  138,  pp 
162-163;  Bull  145;  GF  13,  p  4;  GF  23,  p  3;  GF  70,  pp  3-4 
stratigraphic  and  paleontologic  relations  of Ann  15,  pp  307-397 
unconformity  between  Columbia  formation  and Ann  7,  pp  582-583 
Potomac  and  Tuscaloosa  formations Ann  12,  i,  pp  421-424 
Potomac  or  younger  Mesozoic  flora Mon  xv 
Potomac  plants,  geologic  affinities  of Mon  xv,  pp  333-348 
Potomac  River,  drainage  area  of Bull  140,  p  43 
geologic  conditions  determining  location  of Ann  14,  n,  pp  391-393 
hydrography  of  basin  of Ann  14,  n,  pp  134-140 
pollution  of Ann  19,  iv,  pp  134-146,  147-149,  153,  155, 161 
profile  of WS  44,  pp  20-21 
rainfall  and  run-off  in  basin  of Ann  20  iv,  pp  1 17-121 
stream  measurements  in  basin  of .Ann  18,  iv,  pp  18-35;  Ann  19,  iv,  pp  132- 
162;  Ann  20,  iv,  pp  117-132;  Ann  21,  iv,  pp  95-100;  Bull 
131,  pp  87-89;  Bull  140,  pp  41-61;  WS  11,  pp  8-11;  WS  15, 
pp   15-22;    WS    27,    pp   19-22,   23-25;    WS   35,    pp   84-95 
water  power  on . . .  Ann  21,  iv,  pp  100-106 
Potosi  limestone  of  Missouri,  character  and  occurrence  of Bull  132,  pp  17-18 
Potosi  rhyolite  series  of  Colorado GF  57,  pp  5-6,  9, 14 
Potsdam  horizon  of  Nevada,  fossils  of Bull  30,  pp  32-33 
Potsdam  horizon  and  pre-Potsdam  land  surface  in  Grand  Canyon  region Ann  7, 
p414 
Potsdam  sandstone,  description  of  the  rock  as  one  of  the  educational  series Bull 
150,  pp  79-80 
fossils  from .Bull  81,  pp  222-235 
in  Alabama Bull  81,  pp  305-307 
in  Arizona,  literature  of,  references  to Bull  81,  pp  219-221 
in  Black  Hills  region Bull  86,  p  257 
in  Canada  and  Great  Lakes  region Bull  81,  pp  207-208;  Bull  86,  passim 
in  Colorado Bull  81,  pp  209-210,  352-354 
in  Dakota,  references  to  literature  of Bull  81,  pp  214-216 
in  Delaware Bull  81,  p  123 
in  Iowa Ann  11,  i,  pp  333-334;  Bull  81,  pp  187-188 
sections  showing  relations  of Ann  10,  i,  pp  559,  560,  561,  562,  564 
in  Lake  Superior  region Bull  81,  pp  190-199 
in  Maryland Bull  81,  pp  289-290 
in  Michigan,  Crystal  Falls  district Ann  19,  in,  p  151;  Mon  xxxvi,  p  481 
in  Minnesota Bull  81,  pp  181-187 
in  Missouri Bull  81,  pp  199-201,  340-341 
in  Montana Bull  81,  p  326 
