LIMESTONE  AND  DOLOMITE,  BIRMINGHAM  DISTRICT,  ALABAMA.       255 
the  dolomite  about  1  mile  north  of  Greene  station,  on  the  Louisville 
and  Nashville  Railroad.  The  outcrop  east  of  Cemetery  Ridge  extends 
northward  as  a  narrow  belt  through  East  Lake,  running  to  a  point  and 
disappearing  beneath  the  dolomite  one-half  mile  west  of  Hoffman.  In 
Murphree  Valley  a  belt  of  this  limestone  half  a  mile  wide  extends  from 
Remlap  to  Chepultepec. 
The  Conasauga  limestone  can  be  readily  distinguished  from  the  over- 
lying dolomite  by  the  following  differences:  The  limestone  is  blue  or 
dark  gray,  without  granular  texture,  and  effervesces  freely  when 
treated  with  cold  dilute  acid ;  the  dolomite  is  generally  light  gray  with 
distinct  granular  texture  and  effervesces  in  cold  dilute  acid  very  feebly 
or  not  at  all. 
It  is  probable  that  the  Conasauga  formation  in  this  region  is  not  all 
limestone,  but  is  composed  of  alternating  layers  of  limestone  and  shale. 
The  Conasauga  limestone  is  separated  from  the  younger  rocks  on  the 
west  by  a  fault  which  has  brought  it  into  contact  successively  with  all 
the  overlying  formations  as  high  as  the  coal  measures.  The  beds  gen- 
erally dip  at  a  high  angle.  It  seems  probable  that  they  are  affected 
by  minor  folding  or  wrinkling  to  a  considerable  extent.  Such  wrink- 
ling can  be  seen  along  the  road  from  Dolcito  to  Tarrant  Gap,  and  it 
probably  occurs  elsewhere  as  well.  On  account  of  such  irregularities 
in  the  dip  no  reliable  estimate  of  the  thicknesss  of  the  Conasauga  lime- 
stone can  be  made.  It  seems  hardly  probable,  however,  that  it  is  less 
than  1,000  feet,  and  it  may  be  much  greater.  No  use  has  been  made 
of  this  limestone  so  far  as  known  to  the  writer. 
Below  is  an  average  analysis,  by  William  E.  Janes,  of  two  samples 
from  an  old  quarry  near  Wheeling,  northeast  of  Bessemer.  It  was 
kindly  furnished  by  Mr.  A.  Lodge,  of  the  W^oodward  Iron  Company: 
Average  analysis  of  Conasauga  limestone  from  Wheeling  quarry. 
Silica  (Si02) 1.  20 
Iron  oxide  and  alumina  (Fe203+ A1203) .49 
Lime  carbonate  (CaC03) 89. 03 
Magnesium  carbonate  (MgC03) 8. 04 
Sulphur  dioxide  (S02) 115 
This  rock  is  suitable  for  flux  and  for  lime,  but  it  contains  too  much 
magnesia  for  cement  making.  It  would,  however,  manifestly  be 
unsafe  to  draw  any  conclusions  as  to  the  general  composition  of  this 
limestone  from  these  two  analyses. 
The  outcrop  of  the  formation  is  always  on  low  ground,  little  above 
drainage,  and  the  dips  are  high,  so  that  conditions  for  quarrying  are 
very  unfavorable.  Since  there  is  abundant  material  in  the  region  of 
as  good  or  even  better  quality  and  better  situated  for  quarrying,  there 
is  little  likelihood  that  this  limestone  will  be  utilized  to  anv  extent. 
