178  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1906,  PART    I. 
It  is  interesting  to  compare  this  average  with  the  analyses  in  Table 
III,  which  shows  the  analyses  made  for  this  paper  by  R.  S.  Hodges, 
chemist  of  the  Geological  Survey  of  Alabama. 
Table  III. — Analyses  of  gray  ore  from  Tallaseehatchee  mine,  Alabama. 
Location. 
Si02. 
A  1,(>:(. 
Fe. 
Mn. 
P. 
s. 
TiOs. 
1.  Middle  of  east  vein 
32.71 
-17.(12 
19.89 
28.34 
35.68 
111.  IS 
35.38 
20.36 
25. « 17 
13.  17 
35.96 
11.21 
ILL'S 
0.016 
0.53 
a  Aboul  36  feel  wide. 
>>  Win  at  this  point  38  feet  wide.     Hard  ore. 
c  Vein  at  this  point  42  feet  wide    Many  slate  partings  in  the  ore. 
The  most  noticeable  facts  shown  by  the  analyses  in  Table  III  are 
the  relatively  low  iron  content  and  the  high  silica.  The  greatest 
amount  of  iron  occurs  in  the  bard,  massive  variety  of  ore  (analysis  4). 
Although  Tables  I  and  II  represent  a  much  greater  number  of  analyses 
than  Table  III,  the  bitter  is  probably  more  trustworthy,  for  the  ore 
was  not  subjected  to  any  sorting  in  the  sampling.  The  higher  per- 
centage of  alumina  in  the  only  complete  analysis  in  Table  111  shows 
that  much  more  slate  was  included  in  the  ore  than  would  be  inferred 
from  the  other  analyses.  The  average  iron  content  of  the  five  san  - 
pies  calculated  as  r-V..().,is  46.14  percent  as  opposed  to  68.73  per 
cent,  the  average  obtained  from  the  analyses  of  Tables  I  and  II. 
The  silica  is  also  much  higher,  averaging  38.73  as  against  20.78. 
Calculating  the  iron  as  Fe.O...  the  sulphur  as  S02,  the  manganese  as 
MnO.,.  and  the  phosphorus  as  P205,  the  complete  analysis  of  sample 
1  of  Table  III  would  be— 
Completi  analysis  of  samplt  of  gray  iron  orefrom  Tallaseehatchee  mine. 
SiU2 
Al.,<>, 
32.7J 
10.  IS 
rv.o, 
50. 54 
P20, 
.65 
MnO., 
.38 
S02.~.... 
.  03 
Tin,  
53 
95.02 
The  difference  between  this  total  and  100  per  cent  is  probably 
mainly  H20. 
ORIGIN    OF    THE    ORE. 
The  origin  of  the  gray  ores  of  Alabama  has  been  discussed  in  some 
of  the  earlier  reports,  but  misconceptions  regarding  the  precise  char- 
acter of  the  ore  have  led  to  untenable  hypotheses.     In  the  earliest 
