554 Waters of the Pennine Chain, &c. 



called cornstones, and the waters are harder. The 

 waters are apt to be still harder in the Carboniferous 

 Limestone tracts that sometimes rise into high escarp- 

 ments round the borders of the great South Wales 

 coalfield, and in Flintshire and Denbighshire. 



Again, the waters that flow from the northern part 

 of the Pennine chain, as far south as Clitheroe and 

 Skipton, are apt to be somewhat hard, because they 

 drain kreas composed partly of Carboniferous Lime- 

 stone. But, as a rule, wherever they rise in, and flow 

 through strata formed of Yoredale shales and sand- 

 stones and Millstone Grit, the waters are soft ; and 

 this is one reason why so many reservoirs have been 

 constructed in the Millstone Grit regions of Lancashire, 

 Yorkshire, and Derbyshire, for the supply of large 

 towns and cities such as Bradford, Preston, Manchester, 

 and Liverpool. All the waters of the Carboniferous 

 Limestone of Derbyshire, such as the Dove and the 

 Wye, are hard. All the rivers that flow over the 

 Permian rocks and New Red Sandstone and Marl, are, 

 as a rule, somewhat hard, and the waters of the Lias, 

 and the Oolitic and the Cretaceous rocks, are of necessity 

 charged with those substances in solution that make 

 water hard, because the Lias and Oolites are so largely 

 formed of limestones, and the Chalk is almost entirely 

 composed of carbonate of lime. 



It thus happens that, as a general rule, most of the 

 rivers that flow into the sea on the eastern and southern 

 shores of England, as far west as the borders of Devon- 

 shire, are of hard water. The waters of the Severn are 

 less so, but still they contain a considerable amount of 

 bicarbonate of lime in solution. The waters of the 

 Mersey, the Dee, and the Clwyd, are also somewhat 

 hard, while those that flow westward in Wales are soft 



