292 



NATURE 



[June i, 1916 



THE SEARCH FOR NEW COAL-FIELDS IN 

 ENGLAND:' 



'T^ HE search for concealed coal-fields was one of the 

 -*■ subjects considered by two Royal Commissions 

 appointed to consider our coal resources. Since the 

 publication of the report of the second Commission, 

 in 1905, much progress had been made both in 

 locating new coalfields and in defining the areas in 

 which concealed coal-fields could not exist. By 

 "visible coal-fields " were meant those areas in which 

 Coal Measures, with or without a covering of super- 

 ficial materials, cropped out at the surface. These 

 areas alone were shown as coal-fields on geological 

 maps, and to them collieries were at first confined. 

 As the geological knowledge of the country progressed 

 it became clear that the Coal Measures might, and 

 did in certain cases, pass under newer formations, and 



had been proved around the northjem and western 

 borders of the Kent coal-field and under London, and 

 thence in a general north-westerly direction through 

 Buckinghamshire, Oxfordshire, and Northampton- 

 shire, towards Warwickshire and Leicestershire. The 

 existence of this barren tract had been proved by a 

 number of borings in and near London and in the 

 counties named, but its limits had not been ascer- 

 tained. On its north-eastern side rocks older than 

 Coal Measures had been proved at Culford, Lowestoft, 

 and Harwich, rendering the existence of coal under 

 central and eastern Suffolk improbable, though there 

 still remained unexplored a tract extending north- 

 westward through Essex, Bedfordshire, and Rutland. 

 On its south-western side there lay a great area of 

 unexplored ground. The south coast, from Folkestone 

 to Devonshire, and adjacent areas in Sussex, Hamp- 

 shire, and Dorset, with parts of Devonshire, Somerset, 



w 



CRICM 



VISIBLE 



COALFIELD 



^■*cnes;an 



N 



LIMESTONE 



L D E 



TRENT VA L LE Y 



KELHAM 

 BORE HOLE 



VERTICAL SCALE. THREE TIMES THE HORIZONTAL 



Fig I. — Section across the Nottinghamshire coal-field. 



form "concealed coal-fields." A map was shown on 

 which were distinguished (a) areas occupied by forma- 

 tions older than Coal Measures, (&) visible coal-fields, 

 (c) areas occupied by formations newer than Coal 

 Measures. On the last-named concealed coal-fields, 

 so far as they had been found to exist, and the dis- 

 tricts in which the absence of Coal Measures had 

 been proved, were distinguished. Thus the visible 

 coal-fields of Cumberland, Durham with Northumber- 

 land, Yorkshire with Nottinghamshire and Derby- 

 shire, Staffordshire, Shropshire, Warwickshire, 

 Leicestershire, and Somerset with Gloucestershire, 

 were all bordered on one side or the other by con- 

 cealed coal-fields, while in Kent a coal-field not asso- 

 ciated with any visible outcrop had been proved to 

 exist. In South Wales, however, there was no more 

 than a trifling part of the coal-field concealed in the 

 sense mentioned above. 

 On the other hand, the absence of Coal Measures 



1 Abridged from a discourse delivered at the Royal Institution on Friday, 

 March 17, by Dr. A. Strahan, F.R.S. 



NO. 2431, VOL. 97] 



and Wiltshire, were unproved in the sense that no 

 boring had yet reached the base of the Secondary 

 rocks. What these rocks rested upon it was impos- 

 sible to say, but their thickness was likely to be great 

 near the south coast. 



Three examples were selected in order to illustrate 

 the nature of the problems which arose in the search 

 for concealed coal-fields. 



The Nottinghamshire coal-field was illustrated by a 

 section (Fig. i) drawn from near Crich, in Derby- 

 shire, to Kelham, near Newark-on-Trent. Com- 

 mencing in the Carboniferous Limestone, the line of 

 section crossed the visible coal-field in a distance of 

 about 65 miles. Thus far it was founded on observa- 

 tions made at the surface, but it then entered a region 

 in which Permian (Magnesian) Limestone, Bunter 

 Sandstone, Keuper Sandstone, and Keuper Marl in 

 succession formed the surface of the ground. These 

 formations lay unconformably upon the Coal Measures ; 

 they were inclined at a gentler angle, and had not 

 been affected by the folds which had bent the Coal 



