Coal-measures under Oxfordshire. 461 



remarked, to the north of the line in question. Both indicate a 

 PalEeozoic area in Suffolk and northern Essex older than the Coal- 

 measures, and similar to that on the same meridian in South Wales 

 and Gloucestershire which lies to the north of the western Coal- 

 fields. We have, therefore, not merely a well-defined Pembroke- 

 Mendip anticlinal forming the southern boundary of the Coal-fields 

 both in the west and in the east, as proved by the south-eastern 

 Coal-field at Dover, but also evidence of the continuation of the 

 South Welsh pre-Carboniferous barrier of Hull, which forms the 

 northern boundary of the visible Coal-fields due eastwards into 

 Suffolk. It may, therefore, be reasonably inferred that similar 

 Coal-fields, isolated from each other by tracts of older rocks, are to 

 be found in the South Welsh syncline, where it lies buried beneath 

 the Secondary and Tertiary strata. In other words, we may conclude 

 that there are Coal-fields in North Wilts, in the counties of Berks, 

 Oxford, and Buckingham, and the Tertiary basin of the Thames 

 within the limits laid down above, and in a direction indicated in 

 1871 by the Coal Commissioners. 



One such Coal-field, indeed, has already been discovered in a deep 

 boring at Burford, near Whitney, in the valley of the Windrush. 

 The discovery, however, has unfortunately not been followed up, 

 and we do not know whether it is of wide east and west range, 

 similar to that of South Wales, or of Bethune and Namur, or 

 whether it is small and unimportant, like some of the smaller 

 Coal-basins north of the Mendip Hills. It offers a sure basis for 

 other Seep borings, which might have the same industrial effect on 

 Oxfordshire as those which have extended the range of the buried 

 Coal-measures in northern France, ninety miles to the west of 

 Charleroi, and converted a purely agricultural into a great manu- 

 facturing district. There is no practical difficulty arising from the 

 depth at which the Coal-measures may be expected to occur in this 

 region. At Burford they were struck at 1184 feet from the surface, 

 and at Dover at 1113 feet below high-water mark. 



The borings in the area of the London Tertiaries prove that the 

 PalcBOzoic rocks are not buried to a greater depth than about 1200 

 feet below sea-level, and in Hertfordshire to as little as 796 feet. 

 The most important collieries in England are carried on at depths 

 ranging from 1500 to more than 3000 feet. The new light thrown 

 upon the question of the buried Coal-fields by recent discoveries 

 places it in a very different position from that which it occupied 

 in 1871, when Godwin-Austen, Prestwich, and Hull gave their 

 evidence before the Eoyal Commission. 



The boring at Dover, revealing the existence of a valuable Coal- 

 field, now offers a fixed point for further discovery in south-eastern 

 England. That at Burford offers a similar basis for the proving 

 of the Oxfordshire Coal-field. The many other wells and borings 

 made in the area of London, and as far north as Bury St. Edmunds, 

 also afford important information as to the northern boundary of the 

 productive South Welsh syncline. The development of our mineral 

 wealth is of such vast importance that it would be quite worth the 



