eckel.]  IKON    ORES    OF    NORTHEASTERN    TEXAS.  349 
LIST  OF   REFERENCES  ON   TEXAS  IRON    ORES. 
The  following  brief  list  contains  practically  all  recent  publications 
on  the  iron  ores  and  iron  industry  of  Texas.  The  two  papers  by 
Comstock  deal  with  the  Llano  magnetites  of  central  Texas;  all  the 
others  describe  the  brown  hematites  of  eastern  and  northeastern 
Texas.  The  two  most  important  papers  are  those  marked  with  an 
asterisk : 
Comstock,  T.  B.  A  preliminary  report  on  the  central  mineral  region  of 
Texas.     In  First  Ann.  Kept.  Texas  Geol.  Survey,  pp.  230-391.     1890. 
Comstock,  T.  B.  Report  on  the  geology  and  mineral  resources  of  the  central 
mineral  region  of  Texas.  In  Second  Ann.  Rept.  Texas  Geol.  Survey,  pp. 
555-064.     1891. 
Johnson,  L.  C.  Report  on  the  iron  regions  of  northern  Louisiana  and  eastern 
Texas.     House  Document  No.  195,  50th  Cong.,  1st  sess.     1888. 
*  Kennedy,  W.,  and  others.  Reports  on  the  iron-ore  district  of  eastern  Texas. 
In  Second  Ann.  Rept.  Texas  Geol.  Survey,  pp.  7-32C.      1891. 
.     The  age  of  the  iron  ores  of  east  Texas.     In  Science,  vol.  23,  pp.  22-25. 
1891. 
* .     Iron  ores  of  east  Texas.     In  Trans.  Am.   Inst.   Mining  Engineers, 
vol.  24,  pp.  258-288,  862-863.     1S95. 
Penrose,  R.  A.  F.  A  preliminary  report  on  the  geology  of  the  Gulf  Ter- 
tiaries  of  Texas  from  Red  River  to  the  Rio  Grande.  In  First  Ann.  Rept.  Texas 
Geol.  Survey,  pp.  3-101.     1890. 
.     The  Tertiary  iron  ores  of  Arkansas  and  Texas.     In  Bull.  Geol.  Soc. 
America,  vol.  3,  pp.  14-50.     1892. 
GENERAL  GEOLOGY  OF  THE  AREA. 
The  area  included  under  the  heading  northeastern  Texas  comprises 
a  group  of  counties  in  the  extreme  northeastern  corner  of  the  brown- 
hematite  district.  There  exists  a  certain  definite  commercial  basis 
for  this  subdivision  of  the  ore  field,  for  the  deposits  occurring  in 
these  counties  are  so  located  that  any  iron  industries  based  on  them 
must  be  considered  as  tributary  to  two  possible  distributing  points — 
Texarkana,  Bowie  County,  and  Jefferson,  Marion  County. 
Within  the  area  under  consideration  five  geologic  formations 
occur,  representing  the  Tertiary  and  Quaternary  periods.  The  five 
formations  named,  in  descending  order,  are  as  follows: 
Formation.  Period. 
Alluvial  deposits Quaternary. 
Lafayette  sands  and  gravels i 
Claiborne  sands  and  greensands 
Sabine  clays  and  sands 
Wills  Point  clays 
The  alluvial  deposits  consist  of  mud  and  silt,  and  occupy  the  bot- 
tom lands  along  the  larger  streams. 
The  Lafayette  formation  consists  of  yellowish  sands,  with  occasional 
beds  of  coarse  gravel.     These  gravel    beds  occur   at   several   points 
Tertiary. 
