20  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull. 225. 
Professional  Taper  No.  21,  Geology  and  Ore  Deposits  of  the  Bisbee  Quadrangle, 
Arizona,  by  F.  L.  Ransome. 
Professional  Paper  No.  24,  Zinc  and  Lead  Deposits  of  Northern  Arkansas,  by 
George  I.  Adams. 
Professional  Paper  No.  25,  Copper  Deposits  of  the  Encampment  Quadrangle, 
Wyoming,  by  A.  C.  Spencer. 
Professional  Paper  No.  26,  Economic  Resources  of  the  Northern  Black  Hills,  by 
J.  D.  Irving. 
Professional  Paper  No.  27,  Geological  Reconnaissance  Across  the  Bitterroot  Range 
and  the  Clearwater  Mountains  in  Montana  and  Idaho,  by  Waldemar  Lindgren. 
Professional  Paper  No.  — ,  Ore  Deposits  of  the  Bingham  Mining  District  of  Utah, 
by  Arthur  Keith  and  J.  M.  Boutwell. 
Professional  Paper  No.  — ,  Copper  Deposits  of  the  Clifton-Morenci  District,  Ari- 
zona, by  Waldemar  Lindgren. 
An  abstract  of  Professional  Paper  No.  26  appears  in  subsequent 
pages  of  this  volume.  Abstracts  of  all  the  others  have  already  been 
published  in  Bulletin  No.  213. 
The  following  geologic  folios,  which  contain  matter  of  economic 
importance,  are  also  in  more  or  less  advanced  stages  of  preparation: 
Franklin  Furnace,  New  Jersey,  by  J.  E.  Wolff. 
Globe  District,  Arizona,  by  F.  L.  Ransome. 
Nampa,  Idaho,  by  Waldemar  Lindgren. 
Silver  City,  Idaho,  by  Waldemar  Lindgren. 
Bisbee  District,  Arizona,  by  F.  L.  Ransome. 
Silverton,  Colorado,  by  Whitman  Cross. 
Bradshaw,  Arizona,  by  T.  A.  Jaggar,  jr.,  and  Charles  Palache. 
Redding,  California,  by  J.  S.  Diller. 
Sturgis-Spearfish,  South  Dakota,  by  T.  A.  Jaggar,  jr. 
ECONOMIC   WORK    ON    METALLIFEROUS  DEPOSITS  IN  PROGRESS. 
The  economic  work  done  during  the  past  field  season  is  briefly 
noticed  below,  by  geographic  sections,  States,  and  Territories,  alpha- 
betically. 
ALASKA. 
Field  work  in  Alaska  was  actively  carried  on  during  the  last  season 
by  geologists  under  the  general  charge  of  Mr.  A.  H.  Brooks. 
Concise  statements  of  the  results  accomplished  are  given  in  the  follow- 
ing pages  under  these  titles: 
(1)  Placer  Mining  in  Alaska  in  1903,  by  Alfred  II.  Brooks. 
This  paper  gives  a  broad  general  review  of  the  present  conditions  of 
placer  mining  in  various  parts  of  the  Territory,  with  recommendations 
as  to  their  possible  amelioration. 
(2)  The  Juneau  Gold  Belt,  by  Arthur  C.  Spencer. 
This  is  an  account  of  the  geological  relations  and  developments  of 
the  gold-bearing  deposits  in  the  neighborhood  of  Juneau,  in  southeast 
ern  Alaska,  which   also  includes   the  famous   Alaska  Treadwell  and 
adjoining  mines. 
