HYPOTHETICAL COMBINATIONS OF THE ORE ELEMENTS 483 



Computing the excess Silica as Chloropal. 



Limonite. 



Goethite.. . 

 Chloropal, Fe 2 3 , 



3Si0 2 5H 2 



Wavellite 



Kaolin 



Quartz 



Fe 2 3 : H 2 (molecular 



63.60 



26.52 



8.60 

 .39 



.77 



489 : 660 

 3 : 4 nearly. 



34.78 

 50.73 



8.62 



.99 



1.29 



2.60 



471:564 



4 : 5 nearly. 





36.85 







59.10 







5.92 







.45 







.26 







.44 





510 



:599 





5 



: 6 neai 



]y. 



33.66 



57.85 



3.01 



.76 



3.61 



.44 



505 : 595 



5: 6 nearly. 



If the silica is combined with the iron in the form. of anthosiderite, it 

 will be seen that the remaining iron and water in number 5 will be in 

 the proper ratio to form limonite, and hence this seems a probable com- 

 bination ; but in numbers 1, 2, and 6 the iron and water are in the pro- 

 portion of 3 : 4 and 4:5. If chloropal is formed, the iron-water ratio is 

 3 to 4, 4 to 5, and 5 to 6. It is possible that iron and water may com- 

 bine in these variable ratios; but until it can be proven in some way, it 

 seems better to consider them as forming mixtures of the established 

 compounds, limonite and goethite or turgite. 



Chloropal has been found associated with the iron ores in at least one 

 locality in Lehigh county, and it is likewise a better known mineral than 

 anthosiderite, and in this respect its occurrence is more probable. 



Associated Minerals 



Besides the iron oxides already mentioned, namely, limonite, goethite, 

 turgite, hematite, and magnetite, the other iron minerals present in the 

 ore deposits are ilmenite, siclerite, and iron pyrite.* Manganese is asso- 

 ciated with the iron ores in many places, and in several different localities 

 the manganese oxides, psilomelane, and pyrolusitehave been mined and 

 shipped. The analyses show the presence of manganese in all the ores. 



Wavellite occurs associated with the iron ores in several localities, and 

 in one place near Mount Holly Springs it is found in commercial quan- 

 tities. At Glen Loch the wavellite occurs in crystal forms in the old 

 iron ore pit. Quartz crystals are found in a few localities, while chert 

 and hornstone are quite common. Fluorite has been observed in at 

 least three localities, and the quite rare mineral ceruleolactite occurs at 

 the Glen Loch ore mines, in the Little Chester valley. 



Associated Rocks 



In the valley regions the prevailing rock is limestone, which varies in 

 composition from nearly pure carbonate to a form with a high percent- 



* Second Pennsylvania Geol. Survey, D, p. 26, 

 LXIX— Bull. Geol. Soc. Am., Vol. 11, 1899 



