Lesley.] -Lt)- 1 [March , 



Fig. 11, were got in the north gangway, one at 400 yards in, and the other 

 at 475 yards. 



III. Quality of Ore. — The three beds seem to preserve their three 

 individually distinct and different characters. 



The top bed is a hard fossiliferous ore. 



The middle bed is hard, and almost a limestone. 



The bottom bed is soft, rich in iron, and holds but little lime. It looks 

 (theoretically) as if it had always been the water-bearing stratum, and 

 has suffered therefore so complete a washing out that all its original shells 

 have disappeared, and their places and forms been assumed by the oxide 

 of iron. This, however, will be its state only to a certain depth below 

 the present valley bottoms. It will then become a rocky calcareous ore, 

 something like the middle bed. The same is true of it (and the other 

 beds to a less extent) when mined down from the outcrop. They will 

 lose in iron and gain in lime. 



At Bloomsburg " soft ore" holding 85 per cent, perox. iron and only a 

 trace of carbonate of lime, turns into "hard ore" holding 61 per cent, 

 perox . iron and 33 per cent, carbonate of lime. 



At Hopewell furnace "soft ore" of 78 per cent, perox. iron and a trace 

 of carbonate of lime, becomes a "hard ore " of 55 per cent, perox. iron 

 and 31 per cent, carbonate of lime. 



A multitude of analyses show the soft ore to range in its peroxide of 

 iron between 30 and 75 per cent. "Where the dip is steep the breast of 

 soft ore is of course short ; where the dip is flat the breast of soft ore is 

 very extensive — as between Griffith's and Walter's, and so on into Dutch 

 Corner. Where the bed spreads as a surface-coating to a broad and gen- 

 tle hillslope it is in its highest prime condition, both of richness and for 

 cheap and abundant mining. It is here about a 50 per cent, ore ; that is, 

 it will allow of getting oue ton of iron from two tons of ore, or practically 

 two tons and a quarter. Prof. H. D. Rogers, who made a careful, special 

 study of this important subject at Danville and Bloomsburg, concluded 

 that when the hillside sloped 15° and the ore beds dipped into it 30° the 

 softened part of the bed extended downwards about 40 yards, and he as- 

 sumed this as the basis of his calculations of quality. 



IV. Quantity of Ore. — From St. Clairsville to Griffith's ; steep dip. — 

 (a.) From opposite St. Clairsville to Weiset's the outcrop descends the 

 mountain slope 3,200 yards to water level in the brook. Taking 40 yards 

 as the depth of the soft ore, thickness (in 12 feet of measures) 40 inches 

 (1 1-9 yard) of ore, and 2 tons to the cubic yard, we have 280,000 tons 

 of soft ore ; say one-half of this lies above brook water level. 



(6.) From Weiset's to Griffith's; dip growing less steep. — Outcrop always 

 from 25 to 35 feet above brook level, on east side of Black Oak Ridge, 

 1,900 yards. Soft ore say 50 yards down ; tons 210,000 ; mostly below 

 brook water level. 



(c.) From Griffith's to (shaft 100 yards east of road north of) Walter's ; 



