THE IROX BEvVRlNG MEMBER. 



281 



Auah/ftei-i of dotjehh' iron ort-s. 

 [The aualyses from tlio (Jolbj- are averages. The analysi.s from the Ashhiml i;s the average of 4R cargoes.] 



Colby. 



MoiiDt Hope. 



formerly 

 Iron King. 



TCnrrie. Aurora. Aahlaml 



Korth. ; South. , Kortb. 



Iron . 



I 6100 



Manganese 2*00 



Alumina 1*75 



Lime ' 'll 



Magne.sia '23 



Silicji 4-50. 



Phosphorus 049 



Sulphur -07 



59-30 



4-00 



1-68 



■10 



■25 



2-50 



•049 



•06 



60^85 

 1^30 



o 

 (*) 

 (') 



5-44 

 ■027 

 (♦) 



South. 



55^74 



12-28 

 (*) 

 (*) 



(*; 



3-47 

 •034 

 (*) 



I 



62-83 



(') 

 (') 

 (*) 

 (•) 

 518 

 •0474 

 (*) 



62-93 



CI 

 (') 

 (*) 

 (*) 

 365 

 -0278 

 0*) 



64-50 



(•) 

 (*) 

 (*) 

 (■) 

 3-65 



-047 

 (*) 



' Undetermined. 



The soutli (lepo.sits carry iiptin an average more niang'ane.se than tlie 

 nortli deposits. The content of inauo-anese in the south Mount Hope is 

 much gi'eater tlian tlie a\erag-e for the di.strict, althoug-li some quantity of 

 ore has been taken from tlie Colby which runs aliove 30 per cent in 

 metallic raano-anese. In the mine itself streaks varyino- from a mere film 

 to those a number of inches in width, compo.sed of almost pure pyrolusite, 

 may be" seen intersecting- the main mass of the iron ore. "Alumina is 

 found in most of the ores, the amount var\iiig from O-fi to 5 per cent. 

 The sulphur varies from 0-()3 to (»13 per cent. Water to the extent of 5 

 per cent exi.sts in the hard ores, and to a greater amount in the softer vari- 

 eties." It a])pears that a ])ortion of this water is combined; that is, that 

 the hematites are somewhat hydrated. • 



The original condition of the rocks of the ore formation, the series of 

 alterations by which the}' have become changed to a ferruginous chert 

 and t<:) othier varieties of rock in the formation, have been fully considered. 

 In several localities the exact facts observed as to these alterations have 

 been recorded. We then have before us the character of the iron ores, the 

 shajie of the deposits, their relations to the rocks immediately about them, 

 the nature of the rocks of the inm formation above the ore horizon, and the 

 character of tlie rocks above and below the iron foiination. An .-ittempt 

 will now lie made to a[)ply these facts to tlic changes which have occurred 

 to the particular area of the iron formation in which the ore occurs, and 

 to suggest an explanation of the character and location of the ore bodies. 



