6 1 2 Building Stones. 



Parliament were chiefly built of this stone. In dis- 

 tricts where it occurs, in Nottinghamshire and York- 

 shire, there are churches, and castles such as Conisbro', 

 built of it, wherein the edges of the stones are as sharp 

 as if fresh from the mason's hands. You can see the 

 very chisel-marks of the men who built the castle, in 

 days possibly before, but certainly not long after the 

 landing of William the Conqueror. 



The Carboniferous Limestone also is an exceedingly 

 durable stone. The Menai bridges were built of it. 

 In Caernarvon Castle the preservation of this lime- 

 stone is well shown. The castle is built of layers of 

 limestone and sandstone, the sandstone having been 

 chiefly derived from the Millstone Grit, or from sand- 

 stones interstratified with the limestone, and the lime- 

 stone from quarries in Anglesea, and on the shores of 

 the Menai Straits. The limestone has best stood the 

 weather. Sandstone, though durable, is rarely so good 

 as certain limestones, which, being somewhat crystal- 

 line, and sometimes formed to a great extent of 

 Encrinites, also essentially crystalline in structure, have 

 withstood the effect of time. 



The Carboniferous Sandstones in Lancashire, Derby- 

 shire, Yorkshire, and in Wales and Scotland, afford 

 large quantities of admirable building material, which 

 has been used almost exclusively in the building of 

 Leeds, Edinburgh, Glasgow, and many other towns. 

 Some of it is exceedingly white, is easily cut by the 

 chisel, and may be obtained in blocks of immense size. 

 But in some of the beds there is so much diffused iron, 

 not visible at first sight, that in the course of time this, 

 as it oxidises, produces stains which discolour the ex- 

 terior of the buildings. 



Unlike limestones, basalts and other hard and tough 



