Excise duty cap for stone and plaster goods limits levy to a prescribed ad valorem rate, reducing excess duty. The Central Government, under sub rule (1) of rule 8 of the Central Excise Rules, 1944, exempts goods falling under sub heading No. 6807.00 of the Central Excise Tariff Schedule from so much of the excise duty as is in excess of the amount calculated at the prescribed ad valorem rate.