210 GEOLOGY AS AN ECONOMIC SCIENCE 



a clear idea as to the actual and possible limits of 

 our coal-fields, and definite indications as to where 

 further prospecting would be either useful or 

 profitless. Unfortunately, even since detailed geo- 

 logical maps have been available for public reference, 

 ignorance or lack of confidence has caused much 

 capital to be expended in the abortive search for 

 coal in places where the very nature of the geological 

 formations forbids its presence. 



The topographical re-survey of Great Britain, 

 on a scale of six inches to one mile, has allowed of 

 those beautiful maps of the Ordnance Survey being 

 made the foundation on which to place the detailed 

 geological work that was found by experience to 

 be necessary for the correct understanding of the 

 superficial and underground structure of mining or 

 industrial areas. 



There is, perhaps, a feeling amongst those less 

 acquainted with geology and its applications that 

 the construction of a geological map is a mechanical 

 process, and that when once the surface has been 

 surveyed and the information recorded nothing more 

 remains to be done. This, however, is far from the 

 truth, for in a country such as ours where vegetation 

 and superficial accumulations occupy large areas, 

 the natural exposures are not continuous but are 

 hidden locally. It is one of the duties of the 

 geological surveyor to note all these natural ex- 

 posures, and from a study of them to lay down on 

 his map a suggested continuation of the solid strata 



