GEOLOGY IN ECONOMICS AND EDUCATION. 49B 



very first importance. The relative thicknesses or special 

 natures of the local geological formations round a village, 

 town or city make all the difference between success and 

 failure in a water supply both as regards quality and 

 quantity. But it is almost like carrying coals to New- 

 castle to make an assertion like this in Liverpool. All 

 the city is well aware that its original water supply owed 

 its first success, as well as its subsequent failure, if I may 

 call it so, purely to geological considerations, namely, to 

 the thickness, the characters and dislocations of geological 

 formations in and around the city itself ; and all the water- 

 bearing formations of the British Islands, like those of 

 Liverpool, have each their fixed geological position, which 

 the trained geologist knows, or should be able to ascertain 

 for himself or for his employers. Or further, if we have 

 to deal with the great surface water supplies brought 

 from a distance, like that of Vyrnwy brought into your 

 own city, Thirlmere for Manchester, or Rkuyader for 

 Birmingham, we find that the water engineer is dependent 

 upon the facts furnished to him by geology and the 

 geologist. The catchment basins of the reservoirs must 

 be floored by an impervious geological formation, his great 

 retaining dams must lie on solid geological ground and 

 guaranteed safe by the practical geologist. It is to the 

 geologist that he applies for information for the necessary 

 materials of which his dam is to be constructed — puddle, 

 clay and building stone. From the geologist and the 

 geological maps and sections he should obtain the desired 

 information respecting the extent, the character and the 

 range of all the rocky material his aqueduct must be cut 

 through — whether in open work or in tunnel — along its 

 entire track from his storage reservoirs to his district of 

 supply. When W3 realise that the original cost of such 

 great overground waterwork undertakings to companies or 



