The Discovery of Ironstone at Conisbro’.

The following communication with reference to the discovery of ironstone at Conisbro’ appears in a Sheffield paper:—In accordance with your instructions, I have made a geological examination of the neighbourhood of Conisbro’ with a view of reporting upon the ironstone recently discovered, and have pleasure in handing you my report. I was informed on proceeding thither that no information whatever could be obtained from the gentlemen interested in the discovery with respect to the exact locality in which the iron ore had been found, so that the result of my investigation would altogether depend upon my own skill in alighting on the exact situation of the ironstone bed. In this, however, I experienced little or no difficulty, the exact spot having been so frequently mentioned in the report, together with the name of the landowner, that very little inquiry sufficed to bring me to the proper place at which to make an examination. I was likewise sufficiently fortunate to obtain the services of a man who knew the neighbourhood well, and who had taken part in some of the exploring operations.

On alighting at Conisbro’, I soon found the neighbouring hills were principally formed of magnesian limestone of more than ordinary purity, the village of Conisbro’ itself being pleasantly situated on the escarpment or outcrop of the magnesian limestone, which fact will explain the hilly character of the village. The valley, I found, were occupied by the coal measures, and to anyone having the slightest knowledge of field geology, the distinguishing features of the respective formations were most easily traced. So far as the geological aspect of the country did not seem at all favourable to the discovery of a hematite ore deposit, to which I at once directed my attention. The proportion of pure iron obtained from the Conisbro’ iron ore is given in the newspaper report as varying from 37 to 75 per cent., and in one paper I saw it stated that some of the specimens actually contained as much as 90 per cent. of pure iron, being in fact, very little short of pure iron. The variation in quality is certainly greater than usual, and for the sake of comparison I give the yield of the principal iron ores smelted in this country:

Cumberland and Barrow-in-Furness hematite …….. from 50 to 65 per cent.

Forest of Dean . “ 45 to 65 “
Dylas, from Spain “ 45 to 55 “
Northamptonshire “ 30 to 50 “
Frodingham (Lincolnshire) “ 25 to 45 “

Cleveland “ 25 to 45 “

The above figures will speak for themselves, and anyone having had any experience with iron ore deposits will find considerable difficulty in understanding how a much purer iron ore than the one found in the Barrow in-Furness district could be deposited. The Conisbro’ iron ore deposit is said to extend from against the Holywell Brewery to Micklebring, the surface of which I found to be occupied by coal measures all the way, and on several occasions I saw thin seams of coal in the bed of the brook. On reaching a point alongside the brook, and opposite the Barks Farm, I found a bed of ironstone some four or six inches thick, which I was informed Messrs Warburton and Rother had been working at the day before, and which was stated to constitute part of the discovery. This bed of ironstone was nothing more or less than ordinary coal measure ironstone, which may be found in all the coal formations of the country, better beds of ironstone than the one I saw having been abandoned at Elsecar, Thorcliffe, and other places because they would not pay for working. My attention was next called to a supposed site of old works in the same field that the Doncaster water shafts are sunk, where I found distinct traces of old cinder heaps, the age of which does not appear to be known. The method of smelting the ironstone appears to have been rude, small furnaces, probably constructed of clay, may have been erected at different spots, where the thin seams of coal measure ironstone came to the surface.

From an antiquarian point of view this discovery is exceedingly interesting, and if further pursued might lead to valuable results; but as far as the deposits of ironstone are concerned, they are such as might anywhere be found along the coal measures from Conisbro’ to Sheffield. The fact that the ironstone extends from Holywell Brewery to Micklebring is sufficient to associate it with the coal measures, which happens to be the exact range of the middle coal measures, from which supplies of ironstone were obtained so long as the beds would pay for working. These remarks apply to the bed of ordinary coal measure ironstone which abound in the neighbourhood of Conisbro’, and I will now explain the other ferruginous deposits which are to be found in this locality.

To the east of Conisbro’ several interesting sections of the coal measures are to be seen, which appear to be higher up in the coal measures than any other exposures in the Yorkshire coalfield. A very good section of these upper coal measures is to be seen in the brickyard east of the village of Conisbro’ and on the right hand side of the road leading to Clifton. The base of this section is fireclay, but higher up are to be seen beds varying from light to a deep red colour, upwards of 30 feet in thickness, on which are to be seen resting the lower beds of the magnesian limestone formation. Although the colouring of these red beds denotes the presence of iron, the beds of red shale and sandstone on proceeding along the road in the direction of the village of Clifton, we walk along the lower beds of the magnesian limestone formation until we begin to ascend into another small valley, on what used to be an open piece known as the name of Clifton Common. I met here with abundance of a very deep red colour, and containing very sparingly nodules of hematite, varying in size from that of a marble to an ordinary boulder. In a few places I found cinders containing a considerable quantity of metal, and showing the ropy structure peculiar to furnace slags. This discovery is, however, nothing new, as in the “Geology of the Yorkshire Coalfield,” a memoir published in connection with the geological survey of England and Wales, is to be found, on page 478, the following paragraph:—“On Clifton Common there is a broad spread of a red or dull purple sandstone. The rocks was strongly impregnated with sesquioxide of iron, and contained nodules of hematite. It seemed to have been once smelted as an iron ore, for at places were lying about. We also picked up a few flint flakes and fragments of rude pottery.” Since the geological survey was made Clifton Common has been enclosed, but there are still to be seen the red beds mentioned and old slags. The hematite nodules are only of local occurrence, and certainly would not pay at the present day for working, while the red beds associated with them, although impregnated with iron to a larger extent than most sandstones, do not contain sufficient iron to be looked upon as a valuable iron ore.

The most correct term perhaps to call them would be ferruginous sandstones, and there can be no hesitation in placing them with the coal measure formation. It therefore appears that little practical good can result from the “find;” in fact, the beds have been seen, examined, and passed over quite ten years ago, and while such able field geologists as those employed on the Geological Survey of England and Wales do not attach much importance to the beds, there is little possibility of gentlemen who only dabble in geology making much valuable discoveries as the one at Conisbro’ has been reported to be in the newspapers.

In connection with the above discovery it has likewise been mentioned that remains of ancient dwellings have been found in close proximity to the iron ore deposits, but Messrs Warburton and Rother appear to have mistaken old coal shafts for ancient dwellings, on part of Clifton Common being literally riddled with them. There is, however, some excuse for this mistake, as the coal appears to have been worked by what are known as “bellpits,” this method of working being of the rudest description, necessitating shafts being sunk within ten yards of each other. Conisbro’, however, is a very interesting spot, and is well worthy of a visit from anyone who takes any interest in antiquarian pursuits.