hayes.]       IRON    AND    NONMETALLIFEROUS    ECONOMIC    MINERALS.  31 
ouglily  investigated.  The  results  of  this  work  have  been  summarized 
in  a  Congressional  document  oji  the  mineral  resources  of  the  Tom- 
bigbee  River  basin  in  Alabama  and  Mississippi,  and  will  be  given  in 
full  in  a  bulletin  on  the  geology  and  mineral  resources  of  Mississippi. 
Work  on  the  summary  of  information  regarding  the  slate  industry 
of  the  United  States,  begun  in  1903,  has  been  practically  completed 
during  the  past  year.  Prof.  T.  Nelson  Dale  has  visited  all  the  slate 
quarries  in  Virginia,  Maryland,  and  Maine,  and  a  report  on  the  slate 
deposits  of  the  United  States  is  now  being  prepared. 
In  connection  with  the  survey  of  the  Penobscot  Bay  quadrangle  by 
George  Otis  Smith  and  assistants,  special  attention  was  paid  to  the 
granite-quarrying  industry.  Maine  ranks  first  among  the  States  in 
production  of  granite,  and  this  quadrangle  contains  a  majority  of  the 
quarries  in  the  State.  Its  survey,  therefore,  afforded  an  excellent 
opportunity  for  a  thorough  study  of  the  industry.  A  special  report 
>n  this  subject  will  be  published  in  advance  of  the  geologic  folio. 
The  investigation  of  clay  deposits  and  the  clay-working  industry 
las  been  carried  on  by  a  large  number  of  geologists  in  connection 
vith  area!  mapping.     In  addition,  some  special  investigations  have 
>een   made.     Clay   forms   perhaps   the  most   important   mineral   re- 
ource  of  Mississippi,  and  special  attention  has  been  paid  to  it  by 
lessrs.  Eckel  and  Crider  in  connection  with  the  collection  of  mate- 
ial  for  the  bulletin  above  referred  to.     The  formations  containing 
eposits  of  valuable  clays  have  been  traced  and  mapped,  and  samples 
ollected  have  been  submitted  to  burning  tests  and  chemical  analysis. 
"he  results  of  this  work  will  afford  much  needed  information  con- 
erning  a  valuable  natural  resource  of  the  State. 
While  State  geologist  of  Arkansas  Prof.  J.  C.  Branner  collected 
large  amount  of  information  on  the  clays  of  that  State,  and  he  has 
nee  prepared  a  report  for  publication  by  the  United  States  Geo- 
•gical  Survey.    Some  time  was  spent  in  the  field  by  Mr.  Eckel  dur- 
g  the  past  year  for  the  purpose  of  bringing  this  report  up  to  date, 
rticularly  with  reference  to  the  clay-working  industry.     It  is  ex- 
cted  that  this  report  will  go  to  press  in  a  short  time. 
A  report  on  the  clay  deposits  and  clay  industry  of  Washington  is 
ing  prepared  by  Prof.  Henry  Landes,  and  a  summary  appears  in 
is  volume. 
Clay  having  peculiar  physical  properties  which  render  il   valuable 
r  a  variety  of  uses  in  the  arts  has  for  some  time  been  known  to 
ur  in  the  Benton  formation  of  Wyoming.     This  clay,  called  ben- 
ite,  has  been  investigated   by  Messrs  Darton  and   Fisher,  and   a 
ef  summary  of  its  distribution,  mode  of  occurrence,  and  properties 
s  been  prepared  for  this  volume  by  Mr.  Fisher. 
