IRON ORES. 



353 



become an inducement for the growth of a vigorous mining industry in the 

 district of which the town of Llano is now the commercial centre. The dis- 

 tribution of these ores is sufficiently indicated by the localities given in the 

 table. 



TABLE II. MAGNETITES. 



Localities. 



1. Iron Mountain, Llano County. 



2. Iron Mountain, Llano County. 



3. Iron Mountain, Llano County. 



4. Iron Mountain, Llano County. 



5. Iron Mountain, Llano County. 



6. Gillespie County (J). Lodestone. 



CD 



<x> 

















5 



o 











.2 



o 





o 



o 



3 

 o 





a 



a 





CD 



a 



o 



"IN 



Sri 







H 



o 



a 











CD 





r3 





S3 



z< 



?< 





fe 



fe 



CQ 



< 



h} 



S 



Ph 



0D 



H 



74.14 

 81.31 



15.41 

 8.12 



3.50 

 4.70 



6.25 

 6.17 



Trace . 





1.02 

 0.02 



0.24 

 Trace . 



100.56 

 100.97 



0.65 



Trace . 



65.40 



16.53 



5.80 



11.07 



0.78 



Trace . 



Trace . 



0.18 



99.76 



65.70 



23.20 



4.70 



4.44 



1.40 





Trace . 



Trace . 



99.50 



77.10 



16.54 



4.65 



0.76 



Trace . 





Trace . 



.75 



99.80 



68.64 



26.49 



5.10 





0.01 









100.24 









63.87 

 63.23 

 58.62 

 64.02 

 66.82 

 68.63 



*Analysis by J. H. Herndon. 



t Analysis by L. Magnenat. 



2. HEMATITES. 



The analysis of iron ores given in Tables II, III, and IV represent really 

 more classes than are indicated by the arrangement adopted. As explained 

 in the preceding pages, there are real magnetites occupying a definite geolo- 

 gic position, and there are also true hematites, with stratigraphic relations al- 

 most as closely restricted, while a variety of the limonites* are distributed 

 according to principles to be explained in another place. In addition to 

 these three classes it might be possible to make up one or two other sets with 

 characters sufficiently distinctive to entitle them to separate consideration. 

 But it is best for the present purpose to group them as in these tables, thus 

 allowing the term hematite to assume a commercial rather than a strictly min- 

 eralogic significance. This adjustment is not at variance with the modes of 

 occurrence of the ores, which naturally fall under three general heads when 

 considered from this standpoint. 



In the Central Mineral Region the true hematites occupy a position midway 

 between the magnetites and the Umonites, in age, in composition, and in mode 

 of origin. Some of them have too little ferrous oxide to be fairly rated as 

 magnetites, although they are anhydrous and resemble magnetite in texture 



*A general name of hydrated iron oxides, as here used. 

 W 



