CONCEALED COAL-FIELDS 213 



were abandoned, so that now the cost of unwatering 

 the old workings practically prohibits the exploita- 

 tion of the lower seams, and should this task be 

 undertaken it is carried on at considerable risk. 

 Further, the caving in of the chambers in a thick 

 seam has often reduced higher coals to an unwork- 

 able condition. 



Geology now furnishes a means of determining 

 not only the horizontal and vertical extent of 

 mineral-deposits, but at the same time will act as 

 a guide to the most profitable method of extraction. 

 To this end every available piece of information 

 with regard to our existing coal-fields is being 

 collected and utilised by the Geological Survey. 



It is with respect to concealed coal-fields, those 

 coal-bearing rocks overlain, and therefore hidden, 

 by newer formations, that geology has rendered, 

 and will continue to render, such signal service to 

 the nation. It is due to the careful labour of the 

 geologist that extensions of our visible coal-fields 

 have been proved to exist, and that new and entirely 

 concealed fields have been discovered. The great 

 extensions of the Yorkshire and Nottinghamshire 

 coal-fields, as well as those of Northumberland, 

 Durham, Lancashire, Somerset and Gloucestershire, 

 are cases in point; while the discovery of the 

 Kentish coal-field was also the direct result of 

 scientific deduction. 



It is interesting to note that according to the 

 report of the Royal Commission in 1905, in a period 



