502 J. W. Davis— The Valley of the Calder. 



sandstone, and only differ from the Millstone rocks above them 

 in this : that the Yoredale rocks are mainly shales with a com- 

 paratively small quantity of sandstone interbedded, whilst in the 

 Millstone-grits, the sandstone beds of which are used for millstones 

 in grinding corn, the characteristic features of their composition 

 are the thick beds of sandstone which occur abundantly through- 

 out the series, and may be seen capping all the hills in this 

 neighbourhood. Just in the same way, the lower and upper 

 members of the great Carboniferous system are characterized; the 

 former by the immense quantities of thick-bedded limestone com- 

 posing it, and the latter by the frequent occurrence of beds of 

 coal. The one called the Carboniferous Limestone, the other the 

 Coal-measures. 



By far the greater portion of the 400 square miles drained by the 

 Eiver Calder and its tributaries is composed of Millstone-grits 

 and Lower Coal-Measures. The Millstone-grits extend from the 

 boundary of the county eastward to a line extended roughly from 

 Halifax a little west of Huddersfield, which would separate them 

 from the Lower Coal-measures. 



The Millstone-grit rocks, with the superincumbent Coal-measures, 

 form parts of an immense anticlinal ridge, whose apex extends 

 along the summit of the chain of hills dividing Lancashire from 

 Yorkshire. On the side of Lancashire the dip or slope of the 

 rocks is very rapid, whilst that on the Yorkshire side of this 

 chain of hills is comparatively gentle. The woodcut on page 504, 

 to which I shall again refer, will explain this relationship. 

 Originally, the Coal-fields of the two counties were united, 

 and formed one large, and, we may suppose, level plain, over 

 which the sea occasionally encroached for long periods. During 

 the Millstone-grit age the sea had the best of it, and during the 

 deposition of the great thicknesses of shale which lay between the 

 grit rocks, the land was under water. The gritstones themselves 

 formed the sea-bed, but were near the shore, and probably washed 

 and ground by every advancing and receding tide — the grains of 

 sand composing the sandstones, when examined with the assistance 

 of a magnifying lens, will be found to be more or less spherical ; 

 the hard, sharp, corners having been removed by the constant 

 rubbing of one particle against another whilst they formed the sands 

 on the shore of this old land. A specimen from the quarry on the 

 edge of the moor will abundantly prove what I have said, and 

 if a piece of stone be chosen with large quartz pebbles inclosed, 

 such as very frequently occur, the rounded and waterworn form 

 will be easily identified. Both the sandstones and the shale are 

 the result of the disintegration of a still older land, just as the 

 Permian Limestone, which stretches in a line N. and S. across the 

 county, a little beyond the confluence of the Calder with the 

 Aire, has been derived from the Mountain Limestone of the Fell 

 district to the north of the Calder valley. The Millstone-grits 

 were probably deposited near the shore, being brought down by 

 rivers from the laud adjoining, whilst the finer and more impalpable 



