3The material in Group 1 comprises only—
(a)rock;
(b)clay;
(c)sand;
(d)gravel;
(e)sandstone;
(f)limestone;
(g)crushed stone;
(h)china clay;
(i)construction stone;
(j)stone from the demolition of buildings or structures;
(k)slate;
(l)sub-soil;
(m)silt;
(n)dredgings.