smith!  CEMENT    RESOURCES    OF    ALABAMA.  425 
Measures.  Although  these  materials  have  not  yet  been  utilized  for 
this  purpose  in  Alabama,  they  have  been  so  used  in  other  States,  and 
there  is  no  reason  to  doubt  that  the  future  will  witness  their  utiliza- 
tion in  Alabama. 
AVAILABLE  LIMESTONES. 
General  geology. — In  northern  Alabama  the  combined  effects  of 
geologic  structure  and  erosion  have  resulted  in  certain  definite  topo- 
graphic types  with'  which  the  geologic  outcrops  are  closely  connected. 
Structurally,  northern  Alabama  is  made  up  of  a  series  of  parallel 
synclines  and  anticlines,  trending  usually  a  little  north  of  east.  The 
anticlines  are  sharp,  narrow  folds;  the  synclines  are  flat,  wide  basins. 
The  effect  of  erosion  has  been  to  cut  away  the  synclines,  and  the 
streams  of  the  region  now  run  along  anticlinal  valleys  bordered  by 
flat-topped  synclinal  plateaus. 
The  plateaus  throughout  most  of  northern  Alabama  are  capped  by 
conglomerates,  shales,  and  sandstones  of  the  Coal  Measures.  The 
lower  Carboniferous  limestones  commonly  outcrop  along  the  sides  and 
at  the  immediate  base  of  the  plateaus.  The  Ordovician  (lower  Silu- 
rian) beds  occur  as  long,  narrow  outcrops  in  the  valleys.  The  middle 
of  the  valley  is  usually  occupied  by  Cambrian  shales  and  the  Knox 
dolomite.  The  Trenton  limestones  would  normally  outcrop  as  two 
parallel  bands  in  each  valley — between  the  middle  of  the  valley  and 
the  foothills  of  the  plateaus.  Faulting  has,  however,  been  so  common 
that  only  one  of  these  bands  is  usually  present,  the  other  being  cut 
out  by  a  fault. 
Lower  Carboniferous. — Limestones  of  suitable  quality  for  cement 
manufacture  occur  in  the  Mountain  limestone  or  Chester  formation 
of  the  lower  Carboniferous.  Perhaps  the  most  accessible  occurrences 
of  this  rock  are  in  the  Tennessee  Valley  to  the  west  of  Tuscumbia  and 
south  of  the  river  and  railroad.  Here  the  quarries  of  Fossick  &  Co. 
were  formerly  located.  Their  quarries  at  this  time  are  farther  east- 
ward, but  at  a  greater  distance  from  the  river,  in  Lawrence  County 
north  of  Russellville.  This  outcrop  extends  thence  eastward  along  the 
base  of  Little  Mountain  as  far  as  Whitesburg,  above  which  place  to 
Guntersville  the  river  flows  through  a  valley  floored  with  lower  Car- 
boniferous limestone.  The  Southern  Railway  passes  over  outcrops  of 
this  rock  in  most  of  the  mountain  coves  east  of  Huntsville,  and  from 
Scottsboro  to  the  Tennessee  line  the  country  rock  is  almost  entirely 
of  this  formation.  The  Louisville  and  Nashville  Railroad  south  of 
Decatur  nearly  to  Wilhite  is  mostly  in  the  same  formation.  These 
two  lines,  together  with  Tennessee  River,  would  provide  ample  means 
of  transportation  for  the  rock  or  for  the  finished  product.  Analysis 
of  the  rock  from  the  Fossick  quarries  is  given  in  the  table  on  p.  432. 
In  Browns  Valley  south  of  Brooksville  the  Mountain  limestone  is 
