SINGH, J. - (1.) The Revising Authority, Meerut, has referred the following questions of law for the opinion of this Court : " (1) Whether, on the facts and in the circumstances of the case, the question whether the notice under section 21 was served on the assessee was open to be canvassed after remand ? (2) Whether, on the facts and in the circumstances of the case, the assessee had due notice of the proceedings under section 21 of the U. P. Sales Tax Act ?" The reference is being treated as a revision in view of section 20 (6-A) of U. P. Ordinance No. 27 of 1978. The two questions in dispute in the present revision are as to whether the assessee had due notice of proceedings under section 21 of the Act and, secondly, whether the question of validity of the notice could be urged by the proceedings under section 21 of the Act, the controversy as to whether objection to the validity of the notice could be taken by the assessee on remand becomes academic. It will, therefore, be convenient to consider the question as to whether the assessee had notice of the proceedings under section 21 of the Act. The dispute arises in the following context. The assessee did not file any return for the assessment year 1957-58. A notice under section 21 of the Act dated 17th April, 1961, was sent to the assessee, and it was treated to have been sufficiently served. However another notice dated 6th March, 1962, was sent to the assessee, service of which was effected by registered post intimating the assessee that the case under section 21 of the Act had been postponed for 17th March, 1962. On 17th March, 1962, one Sri B. B. Gautam, Manager, appeared before the Sales Tax Officer, and asked for an adjournment, which was granted and the case was fixed for 4th April, 1962. On 4th April, 1962, a lawyer on behalf of the assessee appeared, and on his request the case was adjourned to 5th April, 1962. Another adjournment was granted on 5th April, 1962, and the case was fixed for 6th April, 1962. The matter was postponed on the 6th to 16th April, 1962, when the counsel for the assessee appeared. After discussion of the case with the counsel for the assessee, it was adjourned to 18th April, 1962. On 18th April, 1962, certain documents were filed and, thereafter, assessment order was passed on 27th April 1962. The assessee appealed against this order which was allowed on the ground that the assessment could be made only under section 7 (3) of the Act, and not section 21 of the Act, and as the assessment was completed on 27th April, 1962, it was barred by time. As a consequence of this finding, the assessment was annulled. A revision was filed against this order by the Commissioner of Sales Tax, wherein it was held that the proceedings under section 21 could be taken even though the recourse to section 7 (3) had not been taken earlier. As the appeal had not been disposed of on merit the revising authority remanded the case to the appellate authority. The appeal was again allowed on 3rd March, 1970, on the finding that no notice under section 21 of the Act was served on the assessee in accordance with law. A revision filed against this order by the Commissioner of Sales Tax failed, and hence the present reference, which has been converted into a revision. As has been stated earlier, the department relied on two notices, one dated 17th April, 1961, and the other dated 6th March, 1962, for establishing that the assessee had notice of the proceedings, and that the proceedings were not barred by time. So far as the notice dated 17th April, 1961, is concerned, that was served on one Sri O. P. Sharma, and not on the proprietor of the firm. This notice has rightly been held by the appellate authority and the revising authority not to be sufficient for purposes of section 12 of the Act. The real controversy is as regards the second notice dated 6th March, 1962, the copy of this notice is not on the record. There is a receipt of slip in a printed form, which states that proceedings under section 21 of the Act have been adjourned for 17th March, 1962. In the objection filed by the assessee, it is admitted that this notice was received by him. Although this notice is not the initial notice under section 21 of the Act, it undoubtedly informed the assessee that the proceedings under section 21 are being taken against him and the matter has been adjourned for consideration to 17th March, 1962. It is settled that a notice under section 21 is a jurisdiction notice, and no assessment or reassessment in respect of escaped turnover can be made unless a valid notice under section 21 of the Act is issued and served upon the assessee within the time prescribed in that behalf : See Sri Krishna Chandra v. State of Uttar Pradesh [1972] 29 STC 635 (All ). This case is also an authority for the proposition that mere knowledge of the proceedings under section 21 will not validate the reassessment proceedings, in case there has been failure to serve the assessee with a notice under section 21, Thus, a notice of proceedings under section 21 is prerequisite for taxing the escaped turnover of an assessee. The Act does not, however, prescribe any particular form of notice. Therefore, it is not necessary to specify the details as are required by a notice under section 148 of the Income-tax Act : See Hira Lal Ayodhya Prasad v. Sales Tax Officer, Shahjahanpur [1972] 30 STC 365 (All ). Nevertheless, there must be a communication by the Sales Tax Officer to the assessee, apprising him that proceedings under section 21 will be taken against him, and calling upon to put in appearance, so that he may have an opportunity of putting in appearance, and participating in the proceedings. A formal defect in a notice, for example, the mention of a wrong section has been held to be inconsequential, in case the assessee understood the purpose of the notice : See Pawansut Bangle Stores, Firozabad v. Assistant Sales Tax Officer, Firozabad [1966] 18 STC 87 (All ). Does the mention of 6th March, 1962, inform the assessee that proceedings under section 21 are being taken against him and call upon him to put in appearance ? It undoubtedly does. The notice specifically mention section 21 of the Act, and intimation to the assessee that the proceedings have been adjourned to 17th March, 1962. A reasonable and prudent assessee, from this notice, would have no difficulty in concluding that proceedings under section 21 have been started by the Sales Tax Officer against him, and they have been adjourned to 17th March, 1962, on which date he should put in appearance. As is apparent from the order sheet, the assessee did put in appearance and objected to the proceedings both on facts and law. This being so, the notice of 6th March, 1962, though only intimating the adjourned date of hearing of the proceedings under section 21, can be treated as a notice under section 21. This notice was given before the limitation for making the assessment had expired and as such extended the period of limitation, in view of the proviso (i) to section 21 (2) of the Act. The revision is accordingly allowed. The revising authority should decide the case on merits in accordance with law and in the light of the observations made in the judgment. A copy of this judgment will be sent to the revising authority under section 11 (8) of the Act. There shall be no orders as to costs. .;