514  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1904.         L bull.  260. 
On  the  east  side  of  the  creek,  about  100  yards  in  Alabama,  the  Selma 
chalk  forms  a  bluff  a  little  higher  than  on  the  opposite  bank  in  Mis- 
sissippi. Here  what  is  taken  to  be  the  top  of  the  Selma  chalk"  is 
found.  The  top  of  the  bluff  is  capped  by  a  coarse-grained  sandstone, 
cemented  by  lime  carbonate.  In  it  are  lime  concretions  the  size  of  a 
closed  hand. 
The  upper  beds  of  the  Selma  chalk  also  appear  in  the  bluff  on  the 
east  side  of  Quilby  Creek,  7  miles  east  of  Sucarnooche. 
An  outcrop  of  Selma  chalk  shows  on  Scooba  and  Fox  Prairie  road 
where  it  crosses  the  Bodea  Creek,  about  2  miles  west  of  the  State  line. 
A  sample  collected  from  this  outcrop  was  analyzed  in  the  labora- 
tory of  the  United  States  Geological  Survey  by  W.  S.  McNeil. 
Analyses  of  Selma  limestone,  Bodea  Creek,  Mississippi. 
Silica    (Si02) 10.60 
Alumina     (A1203) 
Iron  oxide  (Fe,03) 
Lime  carbonate   (CaC03)__  82.47 
Magnesium  carbonate    (MgC03) Trace. 
Water .82 
Three  miles  north  of  Scooba  the  west  border  of  the  Selma  chalk 
outcrops  in  a  series  of  hills  forming  the  south  bank  of  Wahalak 
Creek.  The  bottom  of  the  Wahalak  here  is  about  1^  miles  wide, 
the  south  bank  retreating  more  rapidly  than  the  north  side.  The 
creek  has  cut  its  channel  into  the  Selma  chalk,  which  outcrops  almost 
continuously  throughout  its  course.  The  limestone  occurs  up  the 
creek  about  6|  to  7  miles  northwest  of  the  town  of  Wahalak,  but  the 
clay  belonging  to  the  Porters  Creek  formation  occupies  the  country 
on  either  side  of  the  creek.  The  hill  just  east  of  Wahalak  is  of 
Porters  Creek  clay,  which  is  not  over  15  feet  thick. 
A  sample  of  limestone  was  collected  from  the  bed  of  Wahalak 
Creek  about  1-J  miles  south  of  Wahalak.  This  sample  was  analyzed 
by  W.  S.  McNeil  in  the  laboratory  of  the  United  States  Geological 
Survey,  with  the  following  results : 
Analysis  of  Selma  limestone  near  Wahalak,  Miss. 
Silica    (Si02) 20.00 
Alumina     (A1203) -> 
Iron  oxide  (Fe203) J     8' 92 
Lime  carbonate   (CaC03) 68.91 
Magnesium  carbonate   (MgC03) , Trace. 
Water   I 1.03 
A  sample  of  the  Selma  limestone  was  taken  from  the  bed  of 
Wahalak  Creek  \\  miles  south  of  the  town,  and  another  sample  was 
taken  on  the  range  of  low  hills  on  the  south  side  of  Wahalak  Creek, 
1^  miles  southeast  of  where  the  Mobile  and  Ohio  Railroad  crosses 
the  creek. 
