A HISTORY OF NORTHAMPTONSHIRE 



pebbles ; in others newer erratics predominate, 

 such as chalk and flint. It is possible that some 

 of the very chalky gravels, such as are met with 

 at East Haddon, Little Brington, and other 

 places, may be post-glacial in age. 



Gravels of almost entirely local material are 

 met with at Pytchley and Brigstock, the former 

 consisting of Great Oolite limestone, and the 

 latter of Lincolnshire limestone. 



River Gravels or Valley Gravels. — The 

 gravels which occur below the present river 

 level of the Nene, and are seldom worked as 

 gravel because of water, are mid-glacial gravels,^ 

 but the true valley or river gravels occurring 

 at various heights above the present River Nene 

 have been worked at many places between 

 Northampton and Peterborough, largely for ballast 

 for the railway line in the past, though little so 

 now. The low-lying gravels are rather inferior 

 in quality, that is to say they are dirty.^ 



IRON ORES 



The Iron industry of Northamptonshire can 

 claim no continuous history from the period of 

 Roman occupation, in spite of its probable exis- 

 tence at that time and even earlier.' Domes- 

 day, however, furnishes more certain evidence'' 

 that ironworkers were then to be found in the 

 county, and furnaces were probably still alight in 

 the reigns of the early Plantagenets.^ Soon after 

 all trace of iron-smelting is lost, and when 

 Morton wrote, in the reign of Queen Anne, 

 the very existence of native ore within the 

 county boundaries was denied.^ Not till the 

 middle of the last century did this ancient 

 industry, through the re-discovery of the metal, 

 awake to vigorous life. The re-discovery of 

 Northamptonshire iron ore took place about the 

 year 1850, and was initiated by Colonel (after- 

 wards General) Arbuthnot taking a piece of the 

 ore, not a very good piece, however, to Dr. 

 Percy, at Birmingham. Colonel Arbuthnot was 

 referred to Mr. L. H. Blackwell, of Dudley, 

 who visited the county and sent specimens of the 

 ore to the Great Exhibition of 185 1. 



The first ore smelted in the district was in 

 February, 1852, by Mr. Thos. Butlin, who a 

 little later commenced the manufacture of iron 

 commercially at the East End, Wellingborough, 

 under the title of Messrs. T. Butlin & Co. 



The iron in the Northampton sand that is 

 mostly worked for smelting is in the form of 



' y.C.H. Northants, i, 28. 



' Beeby Thompson, ' The Cow Meadow Gravel 

 Pit,' Journ. Northants Nat. Hist. Sec. xi, 207. 



' F.C.H. Northants, i, 152, 206. 



' Ibid, i, 304 ». 



' Harl. Ch. 49 G. 51 (B.M), and of. Morton, 2V<?A 

 Hist, of Northants, 550. 



' Morton, op. cit. 549. He believed the early 

 smelters had imported ore from other counties. 



brown hasmatite, or Limonite, a hydrated ferric 

 oxide ; but this is not always the case, and it gives 

 little idea of the variableness of the rock in 

 which the iron occurs. For instance, the colour 

 may be either yellow, red, brown, almost black, 

 grey, green, or bluish green ; and the matrix be 

 essentially either siliceous, calcareous, or argilla- 

 ceous (earthy) ; indeed, different beds in the same 

 quarry might give all these three different kinds, 

 hence a proper selection of the ore may be a 

 matter of considerable importance in producing a 

 uniform quality of iron. Taken as a whole, the 

 ore may be described as siliceous, and limestone 

 is used as the flux for it, though it should be 

 mentioned that the most compact ore has oolitic 

 grains disseminated in it, and all forms are pretty 

 sure to yield some rounded and subangular grains 

 of quartz. 



So far as colour goes, any one of the three 

 main kinds of stone mentioned above may be 

 yellow to dark brown ; the more sandy beds being 

 pretty uniformly coloured, and the calcareous and 

 argillaceous ones irregular, and very commonly 

 consisting of one mass of cells of various sizes, 

 composed of concentric layers, oval or subangular, 

 of rich dark iron ore, enclosing a nucleus of yellow 

 or red argillaceous or sandy matter, or green 

 oolitic carbonate of iron, the so-called cellular 

 ironstone. 



The green and grey ironstone is essentially 

 oolitic carbonate of iron, the oolitic granules being 

 from yjj to ruTJ of an inch in diameter. The 

 grey variety is especially characteristic of deep- 

 seated iron ore, where percolating water has not 

 been able to oxidize and redistribute the iron, 

 and in these situations, as a rule, a much greater 

 thickness of the grey ore occurs than is ever 

 found of the green. 



The workable ironstone is always low down 

 in the Northampton sand, and may vary in thick- 

 ness from 4 ft. to 20 ft., the average being 9 ft. or 

 10 ft., but occasionally the lowest beds, those 

 resting on the Upper Lias clay, are discarded for 

 one reason or another. At Pen Green, near to 

 Corby, they are discarded because too argil- 

 laceous ; at Duston and other places they are 

 discarded because containing too much phos- 

 phorus. These bluish-green beds that are refused 

 because of the supposed presence of phosphate of 

 iron in them, however, contain no more, and 

 maybe less, phosphoric acid than some of the 

 brown ore. The blue-green colour may be due 

 to silicate of iron in part. 



The average yield of ore per acre has been 

 put at 10,000 to 12,000 tons,' but, of course, is 



" For information on many points that cannot be 

 included in this article, see ' On the Northampton 

 Iron Ore District,' by W. H. Butlin, B.A. Camb., 

 a paper read at the annual meeting of the Iron and 

 Steel Institute, May, 1883 ; and also, by the same 

 author, an article ' On the Smelting of Northampton- 

 shire Iron Ores,' in the Iron and Coal Trader Retieui 

 (1884). 



306 



