11M5 MINERAL PRODUCTS 



§ 1. B&OWH HEMATITE, \M' "\li MANGANESE. 



The brown hematite and oxide of manganese arc associated in the same beds, and arc 

 derived from sources originally the same. I bave already stated thai the Stockbridge lime- 

 stone often passes into thin talcose Btrata, in which a peculiar ferruginous Looking sub- 

 Btance abounds. These layers, bj exposure to the atmosphere, become yellow from the 

 presence of ochre which appears diffused through them. Bui they always disintegrate 

 rapidly, and form deep j cllow daj s, u Inch, on being penetrated, furnish nodules of oxide 

 of iron; or, in places where there is a greal accumulation, beds of the ore are found lying 

 wholly disconnected with the rock in the common acceptation ol the word. In some in- 

 stances the ore is collected in beds in a line drift, or soft material containing round pebbles, 

 frequently granular quartz, and occasionall] Btockbridge limestone. It is difficult to de- 

 termine whether the materials forming these beds have been transported or not. The} 

 appear to have been carried into depressions by the slow operation of common or ordinary 

 causes, simultaneously with the disintegration and decomposition thai detached and sepa- 

 rated the panicles from their common matrix. The beds thus formed may have been 

 enveloped in drift, with the partial destruction of the accumulated materials. 



hematite embraces the usual varieties of imitative forms, as botryoidal, mammillary, 

 Btalactitic, etc. Large globular hollow masses are often met with in the excavations, of 

 sufficient capacity to hold a barrel of water, and sonu ■limes water is found in them. The 

 interior of these large globes is lined with a splendent coating of manganesian matter, 

 spread over the vertical fibres which terminate inwards. The outside is always rough with 

 projecting points of hardened ore. 



The manganese is usually collected in masses amidst the iron ore : it is in imperfectly 

 compacted masses, or in that condition called wad. In other instances, it is in hard rough 

 black masses, with a fine granular or earthy texture; and sometimes in fine necdleform 

 crystals of excet dingl] high metallic lustre. 



A range of beds of hematite extends from Westchester county, through Salisbury, 

 Ann tiia. Stockbridge, Richmond, Bennington, and onwards to the Canada line. All 

 the independent ranges Of the Taconic rocks furnish beds of hematite. 



Associated with the same beds is the gibbsite, an aluminous mineral occurring in the 

 form of incrustations, and pendent among the masses of ore in stalactites or tuberous 

 masses. Fine whin- clays also abound, which appear of the same composition as the 

 gibbsite. White carbonate of iron is also quite common, usually in rounded or kidney- 

 form masst s. 



The different minerals enumerated above are derived from the magnesian slates and 

 limestones, and not from the taconic slate. 



