26  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull.  225. 
and  has  prepared  a  brief  summary  report  on  the  structure  of  the  field 
and  the  character  and  distribution  of  the  coal. 
Mr.  W.  T.  Griswold  has  continued  his  detailed  investigation  of  the 
geologic  structure  in  the  southeastern  Ohio  oil  fields,  the  methods  and 
results  of  which  were  described  in  the  last  economic  bulletin  (Bulletin 
213).  The  work  has  been  extended  eastward  from  the  Cadiz  quad- 
rangle over  the  adjacent  Steubenville  quadrangle.  Important  conclu- 
sions have  been  reached  regarding  certain  necessary  modifications  of 
the  anticlinal  theory  of  oil  and  gas  accumulation,  a  statement  of  which 
will  be  made  in  a  forthcoming  bulletin  of  the  Survey. 
During  the  past  season  George  I.  Adams  and  assistants  made  a  detailed 
investigation  of  the  lola  oil  and  gas  district.  Special  attention  was 
given  to  the  measurement  of  gas  pressures  and  volumes  in  order  to 
determine  the  probable  life  of  the  field. 
Mr.  N.  M.  Fenneman  has  completed  the  investigation  of  the  Boulder 
oil  field,  and  is  preparing  a  full  report  on  the  geology  and  mineral 
resources  of  this  district.  A  summary  of  this  report,  giving  important 
conclusions  regarding  the  structure  of  the  field  and  its  relation  to  the 
oil  pool,  appears  in  this  volume. 
One  of  the  most  important  investigations  on  the  fuel  resources  of 
the  countiy  undertaken  during  the  past  season  was  that  by  G.  C. 
Martin  on  the  petroleum  fields  of  Alaska  and  the  Bering  River  coal 
fields.  While  the  amount  of  development  in  the  oil  fields  has  not  yet 
been  sufficient  to  enable  conclusions  of  great  importance  to  be  reached, 
Mr.  Martin's  work  has  brought  to  light  extremely  valuable  coal  depos- 
its, which  must  be  of  the  highest  importance  to  the  entire  Pacific  coast 
of  America. 
Cement,  stone,  and  other  building  materials.— -The  policy  of  summa- 
rizing each  year  all.  available  information  regarding  some  important 
mineral  product  has  been  carried  out  during  the  past  season  by  the 
investigation  of  the  cement  resources  of  the  United  States.  The  work 
has  been  in  charge  of  E.  C.  Eckel,  who  visited  all  producing  cement 
districts  and  personally  examined  a  large  proportion  of  the  cement 
plants.  The  results  of  his  work  on  this  industry  will  therefore  contain 
much  more  than  a  summary  of  existing  knowledge,  since  he  has  been 
able  to  make  extensive  observations  on  the  geological  occurrences  of 
the  cement  materials  and  the  technical  and  commercial  conditions  sur- 
rounding its  manufacture.  Special  attention  was  given  to  the  investi- 
gation of  the  industry  in  Alabama  and  Mississippi  in  view  of  the  great 
activity  of  the  industry  in  those  States  in  preparation  for  the  probable 
demand  in  the  construction  of  an  Isthmian  canal.  The  geological  rela- 
tions of  the  Alabama  cement  materials  were  investigated  by  State 
geologist  E.  A.  Smith,  and  he  has  prepared  for  this  volume  a  brief 
summary  of  his  report.  The  Lehigh  district  received  special  attention 
by  Mr.  Eckel,  on  account  of  the  great  volume  of  its  production, 
and  a  short  paper  on  the  district  appears  in  this  bulletin.     Mr.  Eckel 
