8  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1905. 
confined  to  Survey  publications,  though  a  few  titles  of  important  papers  published  else- 
where by  members  of  the  Survey  are  included. 
The  results  of  the  Survey  work  in  economic  geology  have  been  published  in  a  number  of 
different  forms,  which  are  here  briefly  described  : 
1.  Papers  and  reports  accompanying  the  Annual  Report  cf  the  Director,  United  States 
Geological  Survey. — Prior  to  1902  many  economic  reports  were  publish*  d  in  the  royal  octavo 
cloth-bound  volumes  which  accompanied  the  Annual  Report  of  the  Director.  This  form 
of  publication  for  scientific  papers  has  been  discontinued  and  a  new  series,  termed  Profes- 
sional Papers,  has  been  substituted. 
2.  Bulletins  of  the  United  States  Geological  Survey. — The  bulletins  of  the  Survey  comprises 
a  series  of  paper-covered  octavo  volumes,  each  containing  usually  a  single  r<  port  or  paper. 
Tin  se  bulletins,  formerly  sold  at  normal  prices,  are  now  distributee!  free  of  charge1  to  those 
interested  in  the  special  subject  discuss*  el  in  any  particular  built  tin.  This  form  of  publica- 
tion facilitates  promptness  of  issue  for  economic  results,  and  most  economic  reports  are 
therefore  published  as  bulletins.  Their  small  size',  however,  precludes  the  use  *>f  large 
maps  or  plates,  and  reports  containing  largo  illustrations  are  therefore  issued  in  the  series 
of  Professional  Papers. 
3.  Professional  Papers  of  the  United  States  Geological  Survey. — This  seri(  s,  paper  cover*  el, 
but  quarto  in  size,  is  intended  to  include  such  papers  as  contain  maps  or  other  illustrations 
requiring  the  use  of  a  large  page'.  The  publication  of  the  seuies  was  commenced  in  1902, 
and  the  papers  are  distributed  in  the1  same  manner  as  are  the  bulletins. 
4.  Monographs  of  the  United  States  Geological  Survey. — This  seri<  s  consists  of  cloth-bound 
quarto  volumes,  and  is  designed  to  include  exhaustive  treatis*  s  on  economic  or  other  geologic 
subjects.     Volumes  of  this  seu'k's  are  sold  at  cost  of  publication. 
5.  Geologic  folios  of  the  United  States  Geological  Survey. — Under  the  plan  adopted  for  the 
preparation  of  a  geotagic  map  of  the  United  States  the-  entire  area  is  divided  into  small 
quadrangles,  bounded  by  certain  meridians  and  parallels,  and  these  quadrangles,  which 
number  several  themsand,  are  separately  surveyed  and  mapped.  The  unit  of  survey  is  also 
the  unit  of  publication,  and  the  maps  and  discriptions  *)f  each  quadrangle1  are1  issued  in  the 
form  of  a  folio.  When  all  the  folios  are  completed  they  will  constitute  a  Gcol*)gic  Atlas 
of  the  United  States. 
A  folio  is  designated  by  the  name  of  the  principal  town  or  of  a  prominent  natural  feature 
within  the  quadrangle.  It  contains  topographic,  geologie-,  economie',  and  structural  maps 
of  the  quadrangle,  and  occasionally  other  illustrations,  together  with  a  general  description. 
Under  the  law  copies  of  each  folio  are  sent  to  certain  public  libraries  and  educational 
institutions.  The  remainder  are  sold  at  25  cents  each,  except  such  as  contain  an  unusual 
amount  of  matter,  which  are  priced  accordingly. 
Circulars  containing  lists  of  these  folios,  showing  the  locations  of  the1  quadrangular  areas 
they  describe,  their  prices,  etc.,  are  issued  from  time  to  time,  and  may  be  obtained  on  appli- 
cation to  the  Director  of  the  United  States  Geological  Survey.  The  following  list  shows  the 
folios  issued  to  date  and  the  economic  products  discussed  in  the  text  of  each,  the1  products 
of  greatest  importance  being  printed  in  italic. 
List  of  geologic  folios,  showing  mineral  resources  described. 
No. 
Name  of  folio. 
State. 
Area 
in 
sq.m. 
Author. 
Mineral  products  described 
as    occurring   in    area    of 
folio. 
1 
Livingston 
3,354 
980 
932 
969 
Iddings,  J.  P.;  Weed, 
W.H. 
Hayes,  C.  W 
Gold,   copper,   clays,    lime 
stone,  coal. 
Coal,  iron,  manganese,  lime, 
clays,  stone,  road  metal. 
Gold,    eop|  er,    quicksilver 
chromite,  stone. 
Coal,  iron,  lime,  stone,  road 
metal,  clay. 
0 
Ringgolel 
Ga.-Tenn 
Cal 
Tenn 
3 
Placerville 
Lindgren,    W.;    Tur- 
ner. II.  YV. 
Hayes,  C.  W 
4 
Kingston 
