220 GEOLOGY AS AN ECONOMIC SCIENCE 



engineer must acquaint himself before his work is 

 commenced, unless he is willing to run the risk of 

 unnecessary labour and expenditure. We have 

 only to turn to the accounts of such undertakings 

 as the laying out of the Great Western Railway 

 by Brunei, the cutting of the Suez Canal by De 

 Lesseps, the piercing of the Alps, the projected 

 Channel Tunnel, and the complicated system of 

 tube-railways beneath the metropolis, to see how 

 dependent these schemes are for their success on 

 the information that geology is in a position to 

 supply. 



Agriculture. 



The modern science of Ecology, if demonstration 

 were needed, has clearly shown how close is the 

 connexion between geology and agriculture. It is 

 obvious that the character and composition of the 

 soil and subsoil of any particular area are dependent 

 upon the weathering and disintegration of solid 

 rocks, and on various geological processes that have 

 operated within the district. There is no doubt 

 that large-scale geological maps showing the dis- 

 position of the superficial accumulations are of 

 considerable use to the agriculturist, for, as con- 

 structed by the Geological Survey, they clearly 

 distinguish between soils due to disintegration and 

 those due to transport. 



Questions as to the suitability of certain soils 

 for certain purposes, as to matters of drainage and 



