190 The Metallurgical Industry of Cleveland. [April, 



are now conducted upon a most gigantic scale. A few details bear- 

 ing on these points may not be out of place at this stage. 



The ironstone of Cleveland is an impure carbonate, but it does 

 not belong to the Carboniferous series of strata, as do the black- 

 bands and the argillaceous or clayband ironstones. It occurs in 

 some nine or ten seams, distributed chiefly through the Middle Lias 

 group of the Oolitic series ; but they are not all worked, nor, from 

 a commercial point of view, are they all workable. The chief 

 source of the ironstone which is at present being worked is the 

 Main Cleveland Seam, the thickness of which is sometimes from 

 17^ to 20 feet, as at the Eston mines. At other mines it varies 

 from this extraordinary thickness down to 15, 11, and even to 

 7 feet. At the Eston mines the ore is worked at a depth of nearly 

 600 feet from the top of the shaft, which opens out on a bleak and 

 uninhabited Yorkshire moor. Sometimes the main seam is split up 

 into two seams by shale and other beds, the upper being distinguished 

 palseontologicalry as the peden seam, and the lower as the avicular 

 seam. Where the main seam is undivided it is generally richer in 

 metallic iron than where it is split into two seams : in the former 

 case the ore may yield from 30 to 31 per cent, of metal, while in 

 the latter the yield is frequently from 28 to 26 per cent, of 

 metallic iron. Cleveland ironstone is highly fossiliferous — indeed, 

 it may be said to be quite charged with animal remains, and conse- 

 quently there always occurs in the iron extracted from it a notable 

 quantity of phosphorus, the presence of which has hitherto rendered 

 the production of steel from it, without puddling, a scientific impos- 

 sibility. Analyses of Cleveland pig-iron give not unfrequently from 

 1-2 to 1*3 per cent, of this troublesome element ; and yet, although 

 it is generally regarded as an undesirable ingredient of manufactured 

 iron, it would almost seem that Cleveland iron, in the form of rail- 

 way bars, has a greater degree of durability than iron which is 

 practically free from phosphorus. Besides the seam referred to — 

 the Main Cleveland Seam — there is another workable seam, known 

 as the Top Bed. Geologically, it is from 230 to 250 feet higher 

 up, resting on the top of the Upper Lias, the chief feature of 

 which is the well-known Whitby alum shale. This Top Bed is 

 only worked at three places — Grlaisdale, Eosedale, and Port Mul- 

 grave, on the coast. At Eosedale there is also a peculiarly depo- 

 sited bed of rich magnetic ironstone, occupying the same geological 

 position as the Top Bed just spoken of. It sometimes yields as 

 much as 49 per cent, of metallic iron. 



In a number of places throughout Cleveland the ironstone 

 deposit has been completely removed by denudation. The total 

 extent of the denuded area is about sixty square miles, but even 

 after making allowance for that fact there is an iron-bearing area 

 of about 420 square miles. In one portion of that area the deposit 



