492 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



And it is precisely the same with all the great varieties 

 of clays, of which, in the form of bricks, most of our great 

 towns are built. They have all their known and their 

 ascertainable positions, and it is the duty of the geologist 

 to ascertain and study and describe the various rocks and 

 rock-sheets themselves in detail, and it is his business to 

 be familiar with those not only available for building 

 purposes, but also those suitable for road making and the 

 like. Over most of our English geological formations the 

 local road metals are soft and indifferent, but in certain 

 districts, such as Charnwood Forest, Shropshire, Cornwall 

 and Devon, rocks excellent for ro>ad making purposes 

 occur, all familiar to the working geologist. Every single 

 district in Britain is bound down irrevocably by the 

 geological conditions of that district as respects its fuels, 

 its building stones, its road metals, its cements and the 

 like, conditions which render these materials relatively 

 cheap and relatively costly, as the case may be. But each 

 district can repair its own deficiencies from elsewhere, or 

 can enrich itself by parting with its surplus, by taking 

 advantage of the geological conditions of other areas. The 

 information obtained and codified by the geologist, 

 properly interpreted, enables the landowner and the 

 business man to ascertain in what other districts the rock 

 he requires is obtainable, where there is likely to be 

 monopoly or a superabundance, and where there is likely 

 to be the greatest demand ; and it is to geology and the 

 geologist that 'the District Councils, contractors and 

 engineers must apply for information as to the nearest 

 district or locality whence they can obtain the minerals 

 they require in the needful abundance and of the necessary 

 quality. 



In matters of water supply, again, the knowledge and 

 the special training of the practical geologist are of the 



