HEMATITE IN CUMBERLAND AND LANCASHIRE. 429 



times in the manner of beds, and sometimes in the manner of veins, 

 and occasionally occupying depressions on the surface of the limestone, 

 immediately beneath the drift. Examples of the bed-like deposits 

 occur at the top of the Carboniferous limestone, as at Frizington, at 

 Winder Gill, and at Bigrigg. Sometimes the floor is uneven, some- 

 times the roof is uneven, and the floor is often nearly all silica, 

 forming a substance called by the miner's " whirlstone." 



Other limestone bands are similarly more or less replaced by 

 hematite. The vein-like deposits are shown by Mr. Kendall's map 

 to lie in lines of fault. Among these are the Salter Hall mines and 

 the Eskelt mines. Of the superficial dish-like deposits, one of the 

 most important occurs at Hod barrow, and in Furness deposits of this 

 kind are common. Some of the vein-deposits, like those of Salter 

 Hall and the Cleator district, run north and south, while others, as at 

 Bigrigg and Frizington, run east to west. 1 



The percentage of peroxide of iron varies with the percentage of 

 silica, so that the ore is poorer as it is more siliceous. In the upper 

 coal measures hematite is found at Millyeat, near Frizington. The 

 formation of the ore is usually dated as prior to the Permian period, 

 because hematite fragments occur in the lower Permian breccia. 



Mr. E. W. Binney, F.R.S., described hematite as interstratified 

 in the lower coal, and there is no doubt that occasionally coal 

 plants are mineralised with hematite. 



In Furness the chief ores are the hard compact purple blue ore, 

 lined with kidney-like concretions and spar, similar to those which 

 occur in the Whitehaven district. This ore specially occurs at 

 Lindal Moor, where it is worked for a thousand yards in a direction 

 running north-west to south-east, in a vein which varies from a few 

 inches to over ninety yards in width. A similar deposit is worked at 

 the Stank mines, and the Yarlside mines. One of the most charac- 

 teristic features of the hematite deposits is the way in which they 

 are interstratified with the surrounding limestone and shale ; but 

 this condition is always due to replacement of the limestone in the 

 planes of bedding by iron ore. It is impossible to speak with any 

 certainty concerning the source of this or other ores ; but although 

 the hypothesis of emanations of vapour and solutions of metallic 

 matter from the deep-seated regions of the earth offer a simple ex- 

 planation, it is probable that we may with more confidence attribute 

 the iron deposits to the insoluble residue left, when limestones are 

 denuded by solution, and attribute their occurrence in veins to in- 

 filtration from above, slowly and during long periods of time. The 

 chemical processes involved in making hematite out of carbonate 

 of iron, are certainly consistent with the ordinary processes of 

 denundation. 2 



Veins of ironstone in the Carboniferous limestone of South 

 Wales extend from near Pontypool to Lydstep Point in Pernbroke- 



1 J. D. Kendall, " Hematite in the Silurians," Q. J. G. S., vol. xxxii. p. 180. 



2 J. D. Kendall, " Hematite Deposits of Cumberland and of Furness," Proc. 

 North of England Institute of Mining Engineers, vol. xxxi., 1882. 



