ENGLISH AGRICULTURE. 83 



are generally replaced by boulder clay, and soils of somewhat 

 inferior agricultural value. 



In the next place, we must notice a large class of soils in 

 association with the coal measures. The coal-fields of this 

 country come in geological order below the magnesiau lime- 

 stone ; they are therefore associated with the magnesian lime- 

 stone and with the new red sandstone. The principal coal- 

 fields are the Northumberland and Durham, the Yorkshire, 

 the Lancashire, the Staffordshire, the Forest of Dean, the 

 Bristol, the Leicestershire, or the coal-field of Ashby de la 

 Zouch, the Warwickshire, the great South Wales coal-field, 

 and others. 



These coal-fields are a source of great national wealth, 

 and have an important agricultural value, because they give 

 us markets for our produce. The black spots on the geo- 

 logical map will be found to contain the names of most of our 

 great manufacturing centres. Within the limits of the 

 Lancashire coal-field we have Wigan, Chorley, Warrington, 

 Blackburn, Oldham, Bury, Preston, Rochdale, Manchester, 

 Birkenhead, and Liverpool ; in the Yorkshire field we find 

 Bradford, Leeds, Sheffield, Halifax, Wakefield, Burnley, 

 Huddersfield, Rotherham, Staleybridge, Chesterfield, and Not- 

 tingham ; and again we may instance Birmingham, Wolver- 

 hampton, Bristol, and Cardiff. 



These coal-fields or black countries give us an unrivalled 

 market for our produce, but it is a singular fact, that for agri- 

 cultural purposes they are not of the highest value ; they are 

 not particularly favourable for agricultural pursuits, and that 

 for more than one reason. In the first place, in the coal-fields 

 agriculture ceases to be a first-class occupation ; it is over- 

 shadowed by the greater mineral wealth which lies beneath the 

 surface. In the second place, there is such a large population, 

 such a large number of roads, and such an immense amount 



>f traffic as to render it rather difficult to carry on agricultural 



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