April 28, 192 1] 



NATURE 



261 



British Iron Ores. 



Memoirs of the Geological Survey. Special 

 Reports on the Mineral Resources of Great 

 Britain. Vol. xii., Iron Ores (continued). 

 Bedded Ores of the Lias, Oolites, and Later 

 Formations in England. By G. W. Lamplugh, 

 C. B. Wedd, and J, Pringle. 1920. 125. bd. 

 \'ol. xiii., Iron Ores (continued). Pre-Carhon- 

 iferous and Carboniferous Bedded Ores of 

 England and Wales. By Sir A. Strahan, Dr. 

 W. Gibson, T. C. Cantrill, Dr. R. L. Sherlock, 

 and Henry Dewey. 1920. ys. 6d. (His 

 Majesty's Stationery Office.) 



THESE two volumes complete the series of 

 six volumes devoted to an account of the 

 iron ores of Great Britain, which will probably 

 form the most enduring- monument of Sir Aubrey 

 Strahan 's tenure of the Directorship of the Geo- 

 logical Survey. We now need only an account 

 of the iron ores of Ireland, which are far from 

 being negligible, in order to complete our know- 

 ledge of the iron-ore resources of the British 

 Isles ; the iron industry of this country is 

 deeply indebted to Sir Aubrey Strahan for the 

 invaluable information which he has placed at 

 its disposal in this series of reports. It cannot 

 be suggested that the work has been done before 

 its time ; the last official account of British iron 

 ores was issued so far back as 1856 to 1862, 

 when Sir Roderick I. Murchison was Director of 

 the Geological Survey, and this consisted for the 

 most part of a collection of analyses of ores made 

 under the direction of Dr. John Percy. 



The best evidence of the care and accuracy with 

 which these analyses were made under the instruc- 

 tions of "the father of British metallurgy" is to 

 be found in the fact that they are still often 

 quoted, and many of them are repeated even 

 in the reports now under consideration. The 

 whole character of the iron industry has, how- 

 ever, been radically transformed within the last 

 sixty years, and ores that were then compara- 

 tively neglected are to-day of the highest im- 

 portance, whilst those that were then being most 

 actively worked are now almost abandoned. This 

 is especially true of the ores to which the present 

 two volumes refer; at that time the bedded iron- 

 stones of the Coal Measures formed the main- 

 stay of the iron manufacture of England, whilst 

 the ores of the Lias and of the later formations 

 had scarcely been touched ; to-day the great bulk 

 of English iron is made from the latter ores, the 

 Carboniferous iron ores being worked only on a 

 very small scale for quite special purposes in a 

 few districts. 



The pre-Carboniferous bedded ironstones are 

 NO. 2687, VOL. 107] 



not to-day of any great importance, but they have 

 been fully and carefully described, and rightly 

 so, for it is scarcely possible as yet to foresee what 

 their economic importance may some day be. 

 The authors might have pointed out with advan- 

 tage the close correspondence between these ores 

 and the ores that have formed the basis of an 

 important industry in Normandy, the latter being 

 also bedded deposits of Oolitic ores consisting 

 essentially of siliceous carbonate of iron, occur- 

 ring just below the Armorican grit of Ordovician 

 age. 



The chief interest in the iron ores of Car- 

 boniferous age will probably attach to the esti- 

 mates of the quantity of such ore that may still 

 remain. Sir Aubrey Strahan's estimate is close 

 upon 7230 million tons ; large as this figure 

 is, it is no doubt far below the quantity that 

 actually exists ; but it is equally beyond doubt 

 that it is far in excess of the quantity that will 

 ever be wrought. In illustration of the former 

 thesis, the ironstones of Northumberland and 

 Durham may be referred to. The only figure that 

 Sir Aubrey Strahan gives for these is 1,500,000 

 tons for Redesdale and district; these particular 

 ores occur at various horizons in the Carbon- 

 iferous Limestone series, and have been worked 

 only at a few points where they happen to out- 

 crop, as at Redesdale, Bellingham, Haltwhistle, 

 etc. The yield of ironstone is stated by two dif- 

 ferent authorities to have been respectively 8470 

 and 9680 tons of ironstone per acre, so that the 

 estimate of quantity here given corresponds to 

 less than 200 acres. Yet these ores are known 

 in places some miles apart; they accompany beds 

 of coal that are notable for their persistence, and 

 there is no reason whatever for assuming that 

 the ironstones are an outcrop formation and do 

 not continue in depth. 



It is, therefore, quite possible that these 

 ironstones may extend over many hundreds 

 of square miles, and, if so, the estimate 

 of the quantity of ore given in the report is 

 but a minute fraction of the amount that actu- 

 ally exists in this area. Furthermore, the iron- 

 stones of the Coal Measures are altogether 

 omitted from the calculation ; yet these ironstones 

 were actually worked, and a century ago gave 

 rise to a quite important iron industry in the 

 northern part of Durham and the adjoining parts 

 of Northumberland, in many places, such as 

 Waldridge Fell, Urpeth, Birtley, Wylam, Hedley, 

 Tow Law, Bedlington, etc., covering an area of 

 probably quite 200 square miles. Mr. William 

 Cargill estimated the yield at Shotley Bridge 

 to be 5324 tons per acre; this appears to 

 have been one of the richest sections, and if, for 



