6io Jet* Glass-sand, &c. 



clay is also often used in manufactures, and the silts of 

 the Wash and of many another river. An abundance of 

 material is found in all of these formations for the 

 manufacture of bricks, earthenware pipes, and so on ; 

 and it is interesting to observe how in this respect 

 the architecture of the country is apt to vary accord- 

 ing to the nature of the strata of given areas. In 

 Scotland and the north of England, where hewable 

 stone abounds, almost all the houses are built of sand- 

 stone, grey and sombre; in many of the Oolitic dis- 

 tricts they are of limestone, and generally lighter and 

 more graceful ; while on the Eed Marls, Lias, and in the 

 Woodland area of the Weald we have still the relics of 

 an elder England in those beautiful brick and timbered 

 houses that speak of habits and manners gone by. 



In the upper Lias clay in Yorkshire, beds of lignite 

 and jet are found near Whitby, which locally forms a 

 not unimportant branch of manufacture. 



The glass-sand used in this country is chiefly derived 

 from the Eocene beds of the Isle of Wight, and from 

 the sand-dunes on the borders of the Bristol Channel. 

 In the Isle of Wight, the sandy strata lie above the 

 London Clay, and are the equivalent of part of the 

 Bagshot sands. They are remarkably pure in quality, 

 being formed of fine white silicious sand. These sands 

 are largely dug and exported to be used in glass-houses 

 in various parts of the country, as in Birmingham and 

 elsewhere, 



A large proportion of the cement-stones of our 

 country comes from the Lias limestone. These lime- 

 stones are not pure carbonate of lime, but are formed 

 of an intermixture of carbonate of lime and aluminous 

 matter. It is found by experience that the lime from 

 this kind of limestone is peculiarly adapted for setting 



