Page:Transactions of the Geological Society, 1st series, vol. 4.djvu/26

 texture, and it seems to be intermediate between common and cannel coal.

These varieties are not found to occupy separate and peculiar seams of the coal formation, but alternate irregularly with one another, as layers of the same bed.

At Wylam they are met with in the following order.

Splint coal is also found at Throckley, Kenton, and some of the Lambton collieries situated on the Wear. Coarse coal occurs at Cockfield and many other places. These two varieties, containing little bitumen and less sulphur, are used in iron foundries, potteries, &c.; and splint serves as a material for building cottages and outhouses in the neighbourhood of Throckley Fell.

Potter's clay is found immediately below the vegetable soil. Its colour is blueish or smoke grey, and sometimes yellow approaching to orange, in consequence of a mixture of iron ochre. It is used in the manufacture of coarse earthenware, bricks, and tiles.