1. All these three cases raise the question relating to liability to tax under S.7 - A of the Tamil Nadu General Sales Tax Act, 1959 . In these cases, the dealer buys raw bones. The raw bones are converted into crushed bones. The process is done through breaking the bones in a disintegrator. In the process of breaking the bones into pieces of 3/8" and 5/8" bones, bone grist, bone - meal, fluff horns and hoof are obtained. Roughly 50 per cent of raw bone is obtained as crushed bone; 15 per cent of raw bone is obtained as bone grist; about 15 per cent is obtained as bone - meal; about 10 per cent is obtained as fluff; about 5 per cent is obtained as horn hoof. The rest becomes waste. The dealers in T.C. No. 337 of 1979 exported crushed bone, but all the three dealers sold bone - meal, bone grist, fluff and horn hoof locally. As far as export is concerned, the Tribunal has remitted the matter back to the assessing officer in order to decide the question whether those sales fall within the scope of S.7 - A(1)(b) or 7 - A(1)(c) of the , and whether the purchase tax is payable with reference thereto. With regard to the others, namely, bone - meal, bone grist, fluff and horn hoof, etc.